Low cost shore protection design criteria, adverse impacts, expected results, and model municipal ordinance

[From the U.S. Government Printing Office, www.gpo.gov]

Low Cost Shore Protection: Design Criteria,
Adverse Impacts, Expected Results and Model
Municipal Ordinance

Paul Knuth
Coastal Research Associates Inc.
September 1981

LOW COST SHORE PROTECTI
DESIGN CRITERIA, ADVERSE IMPACTS EXP2qOE8q@4q4 RESULTS, AND
MODEL MUNICIPAL ORDINANCE

PAUL D. KNUTH
COASTAL RESEARCH ASSOCIATES

for

LAKE ERIE INSTITUTE FOR MARINE SCIENCE
ERIE, PENNSYLVANIA

SEPTEMBER, 1981

Fund6 Jot thiq.6 investigation we12qAe 6q6u12qAni6hed by a g8qAant 0qd08qtom the
Nationat Oceanic and Atmoq.6phe2qAic Admiqn0qi8qzt0qf0qtq-aticn uqnde8qt pq)0qt0qoqvq'04q"q'ioqn4qz o6q@q, the
Coa8qsta44qt Zone Management Act o2q4 1971, (P.L. No. 92-583) and the ammend-
0qme12qxtq,6 o0q6 1976, (P.L. No.94-3q70) thAoqugh the Pennq,8q6y44qZvania 6qrqi8qepa2qttment o2q@q,
Envi8qA0qonqmenta40qt 2qRe8qz0qou08qAce0qz, C0qo0qn4qztat Zone 6qVqana6qgement 6qF4qAaqr-c4qhq.

CONTENTS

I. Shore Erosion Protection: Types of Structures and Their
Relative Success in Preventing Shore Losses.

ii. The Cause and Effect Relationship Between Erosion Control
Structures and Subsequent Downdrift Erosion.

III. Design Criteria That Must Be Met to Provide at Least a
Measure of Success for Erosion Control Structures.

IV. Model Erosion Control Plan

Appendix I. Bibliography

Appendix II. Local Examples of Erosion Control Structures, Their
Application, Success, and Relative Cause aind Effect
on Shoreline Stability.

Work Element 4.a.

SHORE EROSION PROTECTION: TYPES OF
STRUCTURES AND THEIR RELATIVE SUCCESS
IN PREVENTING SHORE LOSSES

General Introduction
The purpose of this section of the report"is to discuss

the various types of shore protection structures and to

determine their relative success in application toward

reducing losses due to erosion and recession. Included in

the discussion is a brief examination of the dynamics of

beach equilibrium. Both structural and non-structural

alternatives will be discussed. The focus of attention is

on the low cost structures and a variety of non-structural

alternatives. Major works undertaken usually at the Federal

level will not be discussed. Such structures require signi-

ficant outlays of money for planning, engineering, and

construction and are beyond the economic means of the

property owner. It is the express intent to develop a

concept that can be adopted by individual property owners as

well as local governments.

Shoreline Dynamics

Shoreline stability in any unprotected natural coastal

zone is controlled by the supply, transfer, and loss of

material (McGill, 1980). In a simple equation sand

accumulation at any point on the shore is equal to the amount

of sand in the system minus the amount lost downshore and/or

the amount lost offshore. Stability of any shore area then

-2-

is a condition dependent on the active agent of erosion in

the shore zonenwaves. Rather than being stible for any

length of time the beach is in a process of dynamic equilib-

rium through time unless the natural processes are thrown

out of balance by a drastic change in beach material or by

storm waves in a 50-100 year event. The supply of sand to

the system originates updrift. The sources are streams

carrying sediment to the littoral and/or material wasted from

the shoreline itself including the sand content of the eroded

bluff. A beach may be temporarily eroded by storm waves and

th en restored by the milder constructional wave. In addition,

the erosion and accretion patterns may occur seasonally. The

long-term configuration of the beach is totally dependent on

supply. For example, the shore will accrete sand and will

prograde when the rate of supply of sand exceeds the rate of

loss.

The*size and character of sediments on a beach are

related to the forces to which the beach is exposed and the

type of material available at the shore. Most beaches are

composed of fine sand, coarse sand, or shingles or gravel

(Shore Protection Manual, 1975).

Quite apart from the problem of long-term shoreline

evolution lies the issue of whether erosion is more

effectively reduced by natural processes or by man-made

devices. The superior recuperative powers of unaltered

-3-

coastal systems are widely recognized. In fact, many

believe that investment in,areas of critical erosion should

be discouraged and we should Leave the systems to achieve a

state of dynamic equilibrium.

This physical process of erosion has not been perceived

as a problem until it has induced an economic impact on

either an individual or a community (Kerns, 1980). Where

beaches protect shore development it may not be necessary to

provide additional works that might interfere with the

natural system. One important reason why individual property

owners are noticing less beach is due primarily to the fact

that updrift structures are trapping sand that would

ordinarily be distributed over a longer reach of shoreline.

In fact most of the structures built are designed to trap

sand. The principal benefit of shore structures is to retain

a narrow protective beach derived from the beach sized

materials eroded from the bluffs and offering potential

protection or, retard to some degree, further recession

(Omholt, 1974).

The principal cause of shore damage is development

historically occurring along the shore. Many of these

structures are now vulnerable to the physical processes of

change and will, in time, be destroyed completely. Separate

protection over the shore reach of a single property within

a larger zone of erosion is difficult and costly. Such

-4-

protection usually fails at the flanks producing accelerated

impact mostly in a downdrfit direction. Development repre-

sents an encroachment resulting in monetary loss to storms

and the increased cost of shore protection.

Selection of an Appropriate Structure

Because of the tremendous variability of physical and

man-related factors, no single protection is considered a

best choice. The physical factors include littoral drift,

sediment supply, nearshore bottom configuration, and the

nature of the bluff material. Man-related factors may

include value of the property being protected, presence or

absence of other shore protection, and the location of

structures with respect to an active bluff or beach.

Unfortunately, the type of protection chosen is limited

to the dollars an individual has to invest in a shore

protection device. The range is complete. We have seen

scrap materials, brush, old cars, appliances as well as

well engineered (and expensive) works.

Given the correct tools and information, it should be

possible to design a "fool-proof" seawall or groin field

which functions as intended without negative side effects.

However, each site offers a different set of circumstances

creating a need for individual site design. It is not

possible to entirely anticipate the particular problems

existing at individual sites (Brater et al, 1974).

-5-

The owner has five basic choices when considering shore

structures:

(1) Pay the high cost of a properly engineered and

proven structure,

(2) Sell the property to an unsuspecting buyer,

(3) Develop his own solution,

(4) . Do nothing, or

(5) Utilize low cost, temporary designs.

Given the heavy cost of conventional beach protection,

the result is a variety of ill-conceived and poorly coordi-

nated private protection schemes which frequently do little

more than exacerbate existing problems.

The most effective structures are very expensive,

usually greater than $400 per foot of protected shore.. The

cost of some structures may be as little as $10 per foot but

this is for rudimentary works that are not expected to last

over time or to sustain a serious storm. In many cases the

cost of the structure may exceed the value of the property

being protected (U.S. Army, Corps of Engineers, 1977).

Low Cost Structures

As stated in the introduction, the focus of this section

is not on the high cost structure. Because of costs the

shoreowner is left with the low cost alternative or one of

the other choices listed above.

-6-

'With few exceptions no low cost structure can ensure-

permanent protection against high lake levels and periodic

severe storms. Low cost structures are exposed to forces

that they are not designed to handle. The ultimate protec-

tion then cannot be provided the property owner at a

reasonable cost. The low cost design can experience damage

by the five to ten year frequency storm. It cannot be

implied that low cost structures or a low cost solution is

acceptable or even available for most erosion situations.

In sheltered waters low cost structures are better

suited. Such structures are defined by cost; less than

$50.00 per front foot for materials and can be installed

without the use of heavy equipment or, less than $125.00

per front foot for materials and,placlement using heavy

construction equipment (Edge, 1976).

Whereas permanent structures are expensive low cost

structtres have the advantage of low first cost. However,

higher maintenance costs and reduced functional life are the

consequence. Private shoreline owners need more accurate,

reliable information about effective low cost protection

methods (Armstrong, 1976).

The Shoreline Erosion Control Demonstration Act of 1974

directed the Secretary of the Army, acting through the Corps

of Engineers "to establish and conduct for a period of five

-7-

years, a national Shoreline Erosion Control and Demonstration

Program." The intent of the program is to 'develop and

demonstrate to the public and technical community methods for

low cost shore protection. Specifically, these methods are

to be developed and demonstrated in sheltered waters.

Sheltered waters are defined as those areas where the design

breaking wave is less than six feet. In addition, the Act

specifically calls for widespread dissemination of the results

of this program (Section 54, Shoreline Erosion Control Act of

1974).

Congress found that "because of the importance and

increasing interest in the coastal and estuarine zone of the

United States, the deterioration of the shoreline within this

zone due to erosion, the harm to water quality and to marine

life from shoreline erosion, the financial loss to private

and public landowners to obtain satisfactory financial and

technical assistance to combat such erosion, it is essential

to develop, demonstrate, and dissemina@te information about

low cost means to prevent and control shoreline erosion"

(Shoreline Erosion Control Demonstration Act of 1974).

Because of the funding available, a great variety of

low cost structures have been experimented with. Of greatest

interest are those sites and techniques used in the Great

Lakes. (see Figures 1-8)

-dew:
-4-0

.-JS_ -

olmoll,it POO Winq

46
47-C:

-@ve!.rrent
Ot.

Vegetation site at Ludington State Park
3.

A-

71 v-,

r7-

Vegetation site at Presque Isle

Breakwaters at Beach 10. Presque Isle. Vi

Oemonstration project at Geneva State Park
liv

:7 2@
..........

4
Sand-filled
nylon tube
groin 3 miles
South of Port
Sanilac, Mi.

Gabion groin, 3
Miles South ot
Port Sanilac. Mi.

-12-

General Discussion on-the Relative Success or Failure of
Shore Structures

A failed structure can be defined as one that was subject

to extreme damage well within the life of the structure and

which, without major repairs, would be a total failure.

Conversely, to be successful, a structure must withstand

the energy of wave attack over the calculated life of the

structure. A full evaluation on relative success can come

only after years of observation.

Durability of a shore structure depends on the number of

storms, their intensity and duration, as well as soil type,

geologic structure of the lake bottom and shore, and the
topography of the shoreline. Site specific variable's prevent

broad comparisons of structural effectiveness (Armstrong,

1976).

A piecemeal approach to solving shore erosion problems

is the major cause of continued failure and consequent finan-

cial losses (Clemons, GLBC). It is entirely possible to

construct a seawall that may be successful in protecting a

beach. Howevert the seawall may experience pressures from

land failure (landslides and slumping) and consequently be

destroyed from the flank or from the rear. The structure

fails because groundwater seepage problems were ignored.

Similarly,.a well-drained slope may fail if the toe remains

unprotected. What is needed to prevent structural failure

-13-

is a comprehensive approach taking into consideration all

aspects of shore processes.

Problems frequently encountered during and after

installation of an erosion control-device include:

(1) Improper Planning.

Often a property owner makes the wrong decision regard-

in g the method or methods of protection. As stated above, a

combination of erosion control structures may be indicated.

(2) Inadequate Construction Methods.

Lack of experience, carelessness or a misjudgment of

forces may result in poor construction. Such structures

have been found to fail in a short period of time.

(3) Improper Maintenance and Repair.

As in the case of any man-made structure, frequent

maintenance and periodic repair is critical to the overall

survival of the structure and to the continuing success of

the design.

In addition, the lack of performance of many structures

is due to the lack of information about the best available

technology. A critical part of the coastal zone management

efforts must be to continue to.bring the most current infor-

mation to the shore owner and the perspective builder of

erosion control structures. The design of effective controls

-14-

is dependent on on-going research and tests of a variety of

designs. The owner and contractor must be @qilling to abandon

traditional designs that have been shown to give only mediocre

results.

Conclusion

It can be argued that coastal stabilization is futile in

the long run. Shorelines are naturally subject to large-scale

recessions and advances through time. Hence, seawalls and

nourishment projects, etc., are at best, only temporary

solutions (Mitchell, 1975). The protection of a particular

piece of property within the context of an eroding shoreline

is difficult, costly, and may prove to be ineffective.

The most effective and economical means of protection

is achieved through coordinated action under a comprehensive

plan which considers the erosion processes over a long period

of time and over the full length of the receding shore (A

Plan for Michigan's Shorelands).

The ten to twenty-five year frequency storm is capable

of destroying shore protection projects and the property they

were designed to protect. Construction of a major protective

device capable of withstanding such a storm is generally

beyond the economic means of the majority of shore owners.

It is important to realize that past practices have

evolved no single "best" design resistant to failure. When

-15-

it is realized that a tremendous percentage, probably well

over 80%, of the money spent by private or'public property

owners on protection has provided ineffectual protection, it

is obvious that it is very important to investigate addi-

tional designs and assess the causes of failure more closely.

The most effective methods of shore protection are

designed to slow the process of erosion. This can be done

by attenuating the erosive wave or preventing.destructional

waves from impacting the shore directly. To be even moder-

ately successful, such structures must have an adequate

foundation and be designed to prevent incremental failure

by flanking or undercutting. In addition, the structure must

be secure from landward influences.

The following section describes the types and methodology

of a variety of designs available. It is emphasized that the

successful application of any design is predicated on a

thorough examination of the site and a careful application

of engineering principles.

TYPES OF STRUCTURAL AND
NON-STRUCTURAL 'TECHNIQUES

All of the various types of structural alternatives can

be reduced to four main types. They are:

(1) Structures designed and intended to establish and

hold a line that limits the lakes encroachment are called

rigid sea defense lines. This category included seawalls,

bulkheads, and revetments.

(2) Structures designed to capture or retain sand in

compartments. The principal example of this category is the

groin structure.

(3) Structures designed to attenuate wave energy. The

primary purpose is to reduce the energy delivered to the

beach face. Within this category are breakwaters of various

design and jetties.

(4) Shore and beach stabilization techniques which

closely approximate the natural processes. Examples in this

category are beach restoration-projects, beach nourishment

projects, and the use of vegetation to stabilize beaches and

bluffs.

In addition, there are several non-structural alterna-

tives available. By definition non-structural alternatives

are things done.to regulate the activities of man in coastal

areas (Parker, 1980). There are two main non-structural

categories. They are:

-17-

(1) Those non-structural techniques that are considered

within the institutional framework of local or state govern-

ment. The category includes structural setbacks, zoning

ordinances, storm water management, insurance programs, and

acquisition.

(2) Those non-structural techniques that are considered

the perogative of the individual property owner. Included in

this category are relocation and site planning. Vegetation

management, dewatering techniques, and runoff control are

considered prop er site planning alternatives.

The choice between structural and non-structural

approaches involves a given level of risk (Parker, 1980).

The structural alternative imparts.a certain confidence that

the threat is being met "head-on" and positive results are

expected immediately. The non-structural technique recognizes

the limitations of structures and considers the long term

advantages of co-existence with the natural processes.

So little effort has been directed toward adopting the

numerous non-structural alternatives that it is difficult to

judge whether erosion costs would be reduced more significantly

by investing additional money in techniq ues or broadening

the range of adjustments to include presently neglected

options such as land use controls, insurance, erosion fore-

casts, etc. (Mitchell, 1975).

-18-

Trends in Structural Alternative Application

During the 1930's and the 1940's seawalls and bulkheads

were the favored techniques used against the forces of

erosion. These structures are very much in evidence in areas

of the coast where development took place preceding that

time, particularly on the Atlantic Coast, but on the Great

Lakes as well.

During the 1950's the trend, headed by the Corps of

Engineers, was with beach nourishment projects. Research at

that time demonstrated the positive nature of sand accumula-

tion as a buffer against erosion. As supplies of sand

dwindled and the costs related to moving it around increased,

the trend moved to sand by-passing systems.

The late 1960's to the present has seen the trend move

toward (1) land use management techniques, and (2) the design

and installation of lower cost structures. The section will

concentrate on seawalls, bulkheads, revetments, groins and

beach nourishment as structural solutions, with passing

comment on jetties and breakwaters. As mentioned previously,

these structures are outside the financial capabilities of

most property owners. Each of the types of shore protection

has its own inherent advantages, disadvantages, and

limitations for a variety of applications.

I. Structures Designed and Intended to Establish and Hold a
Line That Limits the Seats Encroachment

Revetments, Bulkheads, Seawalls

General Introduc tion

Generally, revetments, bulkheads, and seawalls can be

defined as follows:

(1) Revetment - A revetment is the lightest of the

three in terms of construction. It is designed to protect a

shoreline against erosion by currents or light wave action.

It is most often constructed with respect to existing or

prepared slopes.

(2) Bulkheads - Next largest in size, they function to

retain fill placed behind the finished structure. Ideally

they are not sUbject to severe wave action on the open coast.

(3) Seawalls - Seawalls are the most massive of the

three. They are well engineered, complicated structures

designed to resist the full force of the waves (Shore

Protection Manual).

The above definitions should be used in referencing

these structures. Some confusion exists about the difference

between seawalls and bulkheads but the above definitions

clearly separate them according to mass and application as

shore protection devices.

-20-

The three, however, have some things in common. They-

function to separate land and water by the placement of a

physical barrier. They are used where it is necessary to

maintain the shore in an advanced position relative to that

of the adjacent shoreline. They are used when no naturally

occurring beach serves as protection for the shore and,

finally, they are used where it is necessary to maintain a

depth of water adjacent to the structure as in the case of

mooring facilities.

The general advantages of these structures are as

f-ollows:

.(l) They provide positive protection allowing more

intensive use of the adjacent shoreline.

(2) They maintain the shore in a fixed position,

important in cases of shore development.

(3) They can be engineered to provide protection for

an area without a severe incidental amount of damage to

adjacent shore areas.

The general disadvantages include:

(1) They are not as effective in maintaining a beach.

(2) They provide no protection to adtacent areas which

will continue to erode and ultimately expose the flanks of

even the best engineered structure.

-21-

Revetments

Specifically, a revetment is a sloped facing built to

protect existing land or newly created embankments gLgatnst

erosion by wave action and/or currents. They are constructed

shore parallel and serve as armor for the face of the land.

Construction materials vary but all serve to dissipate wave

energy by allowing a degree of run-up as opposed to the

vertical wall which confronts the wave energy more or less

"head-on". There are three essential types based on

construction methods and material used (Dradeau, 1978).

(1) Single Component Revetment (See Figures 9 and 10)

A single component revetment is composed by individual,

unattached components placed directly on the bank or shore or

over a filter material. Construction materials include stone

rip-rap, concrete blocks, tetrapods, sacks (longard tubes),

sand bags, automobile bodies, cellular blocks, or rubble.

Occasionally some inspired application s of assorted debris

is observed.

(2) Pavement Revetment

A pavement revetment is an impermeable application of

concrete or asphalt over the slope serving as an armor plate

against loss of material from the slope. It is used where

applications of-any of the above single component types is

impractical.

(3) Mattress Revetment

Rough Concrete Curb 18 20
with grouted Stone only

4
.EXTREME HIGH V)
HIGH SPRING

MEAN SPRING

MEAN SUMMER

RIP-RAP REVETMENT
LOW
(LOOSE STONE OR SURFACE GROUTED)

Typical Riprap Revetment

RIPRAP (1000 lbt TO 6000 lbs)
WITW ONE-MAN: STONE

LOW, DUNES
12!

CRUSH E D. STONE: UNSCRMNED
NATURAL BEACH
man
SLOPE Z VZ" AND UNDER

-24-

Mattress revetments are broad, flat applications of

gabions or a network of attached concrete, wood, stone, etc.

designed to be flexible allowing some movement while retaining

structural integrity. They may range from articulated concrete

mattresses to automobile tires strapped together.

Generally, revetments have been found to be.successful.

For example, a U.S. Army Corps of Engineers study found that

"the most suitable, least cost structure for protecting that

lake's (Ontario) U.S. shore is a revetment" (Staats, 1981).

Revetments are sometimes placed at the toe of the bluff

to prevent scour due to wave attack. To be effective, revet-

ments need toe protection, provisions for drainage, and must

be built high enough so that most storm waves will not overtop

them. Revetments may be highly effective if properly con-

structed, although they require maintenance to restore

materials used in construction (Michigan Seagrant).

As mentioned above, they are not effective in maintaining

a beach. Built back at the bluff toe and used in combination

with a groin, for example, they may be part of a comprehensive

program of shore protection.

Bulkheads

A bulkhead is a structure or partition installed to

prevent erosion of the land behind it. It is usually vertical

-25-

or consists of vertical sections stepped back from the water

and built parallel to the shore (Shanks, 1978).

Bulkheads are generally constructed of steel or timber

interconnecting piles or of concrete. Some structures stand

many years while many fail after the first storm. Obviously,

the design and construction of the bulkhead must be able to

withstand severe forces not only from the lakeside but from

the land behind it as well. Failures in these structures

result from excavation of the footing by wave action or as

cracks develop as soil and water pressures build in the

landward side. If they are to be a long term solution,

provisions must be made to protect the footing by burying

it deeply, tying into bedrock, or-placing rip-rap in front

to help absorb wave energy. A concrete apron behind assists

in preventing washouts while drains relieve water pressure to

a certain extent. Since its chief function is to hold back

land, it should only be used in protected waters. (See Fig. 11&12)

Seawalls

A seawall is a structure separating land and water areas.

It is primarily designed to prevent damage to an upland area

while retaining its seaward limit in a fixed position (Corps

of Engineers, 1972). Seawalls are massive in design to

withstand the constant attack by waves. They must be able to

maintain structural integrity over time to be considered cost

EXTREME HIGH
HIGH SPRING
-C\l U) F
MEAN SPRING

20
MEAN SUMMER

MASS CONCRETE WALL

Typical Steel Sheet Pile Bulkhead

TOP OF BULKHEAD
SAND FILL

FORMER GROUND
SURF CE
ROUND TIMBER
PILING

TIMBER STRUT

STEEL SHEET PILING

WATER LEVEL
DATUM

12
A

-28-

effective. Structural failure in seawalls is common due to

under design. Proper design elements include:

(1) A capability to withstand large wave forces,

(2) A foundation safe from undermining (a rule of thumb

is two-thirds buried to one-third exposed),

(3) A heightsufficient to prevent overtopping,

(4) A design which limits the effects of flanking, and

(5) A structure which is appropriate for the site. (See Fig. 13)

Seawalls fail for the following reasons:

(1) Scour - The general design of most seawalls presents

an obstacle to the on-rushing wave. The enormous energy of a

large storm wave is driven downwards. If the seawall lacks

protection at its base, continued scour will cause the

structure to fail. (Figure 14)

(2) Omission of tie-backs - The structure must incor-

porate properly engineered tie-backs into the shore material.

Lack of-tie-backs makes the structure vulnerable to toppling

as the soil and water pressures persist.

(3) Lack of return walls - Return walls protect the

seawall from the flanking action that takes place as adjacent

unprotected shorelines recede. As the structure is flanked by

wave action and structural integrity is lost, the consequence

is toppling. As mentioned above, the bulk of the structure

should be below the lake bottom by two-thirds of its mass.

This allows for the natural cycle of sand movement to take

place without endangering the structure.

Typical Concrete Curved - Face Seawall

VARIES

N, 0", ORIGINAL GROUND
SURFACE
BACKFI LL 0*'o

0.
LLJ .0 .0,

U-
A0.0,

0
1@ . ...

001 .0 0
A

M. L. WATER
FOUNDATION
P ILES
W 61 J-*-@SHEET PILES
13

Ak,

- 5t,-5-A'l

OIL

-31-

The greatest disadvantages of the seawall are the

erosional losses of beach material and the difficulty of

recreational access. Some designs, however, largely

eliminate this problem. The normal seawall is vertical but

large successes are reported from convex, concave, sloped, or

stepped faces.

A convex or sloping design is the least effective in

stopping overtopping but are well designed to solve the

problem of scour at the base since the wave is allowed to

11run up" dissipating its energy. The distinct advantage of

this design is in application in protecting the toe of a

bluff from wave erosion while minimizing scour induced erosion

on the beach.

A concave structure is most effective against overtopping

but increases the problem of scouring. As waves hit the

curved face they are deflected back toward the water and

downward. The wave energy is concentrated in front of the

structure increasing the scouring action on bottom sediments.

A stepped wall reduces scouring while improving access

to the beach. A stepped structure is more complicated and

thus more expensive than a simple vertical or sloped structure.

The distinct advantage of the stepped design is the surface

texture. This texture reduces run-up and dissipates wave

energy more than the smooth surface of the other designs.

-32-

II. Structures Designed to Capture or Retain Sand in
Compartments

Groins

General Information

On the Erie County, Pennsylvania shoreline groins are by

far the most common type of defensive structure. The reasons

for this are not clear save for the fact that earlier groins

achieved a moderate amount of success in general application.

Despite their wide use in Erie County, as well as on other

shores of the nation, the detailed operation of the groin is
poorly understood. Failures @an be traced to a lack of

understanding of the functional design of groins and the

littoral processes to which the structures are subjected

(Shore Protection Manual). (Figure 15) (See also, Appendix II)

Groins or groin systems in many locations have achieved

the intended purpose while in other areas only negligible

benefits have resulted. Groins will do exactly wha t they are

intended.to do if they are appropriate to site problems and

objectives (Parker, 1980). When properly placed in a series

along the shoreline, groins-have proven to be a most

effective means of stabilizing a shoreline or creating beach

where there was adequate longshore sediment transport.

Opinions vary on the benefits of groins as protective

structures. The conditions for success vary with site and

wy@ "'A'

-34-

design and the structural integrity of the completed struc-

ture. The purpose, conditions for use, and-the advantages

and disadvantages are discussed below. As in the case of all

structures, prior to construction a complete knowledge and

understanding of the natural processes is critical. Their

functional success and their structural adequacy cannot be

assured without a solid understanding of the natural forces

and processes at work in the area (Parker, 1980)

A groin is defined as a shore protection structure built

perpendicular to shore and designed to build a protective

beach or to retard erosion of an existing or restored beach

by trapping sediments in the littoral drift. Groins define

compartments within which the longshore transport of sand is

largely reduced.

The cost of constructi ng a groin varies widely and is

dependent on location, size of structure, materials used in

construction, and access to the shore zone. They are gener-

ally very expensive as an alternative for the individual

property owner though, as mentioned, they are the preferred

type in Erie County.

Two or more groins on a particular site would constitute

a groin field. Research on the subject shows that the

effectiveness of the fields is dependent on the relative

value of each individual groin in the field. Generally, the

-35-

costs, advantages, and disadvantages are magnified with

additional structures while the benefits expected of multiple

groins do not always occur proportionately. The purpose of

a groin or a groin field can be stated as follows:

(1) To build or widen a beach by trapping littoral

drift,

(2) To stabilize a beach subject to excessive storms

or seasonal periods of advance and recession by reducing the

rate of loss,

(3) To reduce rate of longshore transport out of an

area by reorienting a section of the shoreline to an align-

ment more nearly perpendicular to the predominate wave

direction,

(4) To reduce losses of material out of an area by

compartmenting the beach, usually a relatively short section

of beach artificially filled seaward of adjacent shores, and

(5) To prevent accretion in a downdrift area by acting

as a littoral barrier (Shore Protection Manual).

The typical construction materials for groins include

timber, steel, concrete, or rock. Each provides its own

unique advantages and disadvantages in site specific applica-

tions. Many structures have been built using a combination

of materials. For example, a sheet pile structure may be

given further structural integrity by the placement of rock

on the updrift side to assist-in breaking the force of storm

waves. (See Figures 16 and 17)

TOP VIEW

Q)
SHORELINE

SIDE VIEW

I I Ifill", -LL I [LAI

J-U-i@ -1-1-1. ILLUL L1-11 Ll u.
v Iv LL LJ LL LL i-LI I
7

TIMBER GROIN
L4

11;;-, V-

'00. 1 %-W

oe r

-38-

Depending on wave climate, water level fluctuations, rate

and direction of littoral drift, and, if adsociated with

artificial beach nourishment, a groin or groin field may be:

(1) Effective as shoreline protection,

(2) Detrimental to the beach system by causing

accelerated downdrift erosion,

(3) Ineffective for trapping sediment (Gutman, 1979).

A groin is effective only when one longshore direction

prevails and there is a sufficient supply of materials in

transport (Sanko, 1978) and ineffective where onshore-

offshore movement prevails (Parker, 1980).

In addition, groins are ineffective when they are highly

permeable.and are both too short or too low. Scarcity of

sand in the littoral is also a cause for ineffectiveness,

lacking sufficient volume to build a protective beach.

Artificial nourishment, discussed below, is an additional

structural alternative which, when used in combination, can

reduce the ineffectiveness due to insufficient materials in

transport. In general, the advantages of groin construction

can be listed as:

(1) The resultant beach provides protection to uplands

as well as establishing a potential recreational site,

(2) Groin systems interfere less with the use of a

beach than any other structure,

(3) Their effect may spread over considerable distance

of shore on the updrift side as sand accumulates, and

(4) At those locations where groins viould be effective,

protection can.generally be provided at a lower initial cost

than the other major shore protection works (breakwaters,

seawalls, or revetments).

The disadvantages may be listed as:

(1) They are not as effective as a seawall for contin-

uous.upland protection,

(2) They may be out flanked as storm waves combine with

high water levels removing more of the backshore area on the

updrift side than the structure was designed to protect,

(3) They are ineffective in areas of low sediment

transport,

(4) The area immediately downdrift of the groin may be

subject to increased scour, and

(5) They may be ineffective as isolated units.

Conclusion

A groin or series of groins should be considered only

after a careful analysis of the shore processes predominating

on the site, including an evaluation of the direction of

longshore drift and the volume of sand in transport. If

there is insufficient sand and the additional expense of

artificial nourishment cannot be borne, the concept should

be abandoned as an alternative in favor of another

-40-

structural alternative. Additionally, the impact of the groin

on downdrift areas should be considered.

overall, a groin design'can function as intended if all

conditions are met. As in the case of all structural alter-

natives, the benefits should exceed negative impacts to be

at once cost effective and en-virnomentally safe.

-41-

III. Structures Designed to.Attenuate Wave Energy

Breakwaters

As stated previously, the breakwater concept is not

suitable for individual protection of private property due

mainly to the high cost of construction including a thorough

engineering study. A discussion of breakwaters is provided

mainly to acquaint the reader with their advantages and

disadvantages and to introduce the floating tire breakwater

as a moderate cost structural alternative in sheltered waters.

Breakwaters are seldom built solely for shore protection.

The concept is used mainly to provide protection for naviga-

tion purposes. The size, of course, varies with the amount

of harbor desired and the severity of the prevailing

conditions.

Breakwaters are designed to reduce or eliminate wave

action in their lee. A side effect and a response making

them somewhat suitable as a shore protection device is the

effect on littoral drift. The breakwater, when constructed

fairly close to the shore, blocks the littoral drift by

denying wave energy to the shore. This can cause accumula-

tions of sand behind them as the energy needed to move

material is largely eliminated. The classic example is the

breakwater at Santa Monica, California and a local example

can be seen at Budny Beach on Presque Isle State Park where

-42-

a prototype rubble mound segmented breakwater system was

completed in 1978. The structure at Presque isle was built

for the sole purpose of capturing sand in the longshore trans-

port system. To this extent they have succeeded. However,

the amount of downdrift erosion that has occurred since

construction creates some doubt as to the overall benefits of

the design concept. (See Figures 5 and 18)

By definition, the breakwater is installed parallel to

the shoreline to attenuate wave energy to protect a shore

area, harbor, anchorage, or basin to provide for the safe

handling of boats and ships. They may be fixed (shore

connected or detached) or floating in the case of the

floating tire breakwater (FTB) design.

The advantages then, are primarily:

(1) To protect a beach area without impairing the use-

fulness of the beach, and

(2) To provide sheltered waters for navigation.

The disadvantages include:

(1) A relatively high cost of construction,

(2) A protection only of the shore behind them,

(3) An adverse effect on the downdrift area by removing

sand from the transport system, and

(4) Because of the side effect of sand accumulation, the

area behind a breakwater requires periodic dredging to remove

unwanted sediment in navigation lanes.

Typical Rubble - Mound Groin
41

VARIABLE

WATER LEVEL
DATUM
':J -"'
PROFIL-E

VARIES

ARMOR
STONE

CORE STONE
(QUARRY RUN) t'

7
@
CORE ONE @@ARM@ @NE
U
(QUARRY @RN)

-44-

The Floating Tire Breakwater Design (FTB)

Resea@--(-h,and experience have shown that FTB's are effec-

tive for improving coastal protection under specific wave

conditions (DeYoung, 1978).

The advantages of the FTB are listed as:

(1) Construction costs are lower than those of conven-

tional breakwaters, and large quantities of material are

generally available. Their construction can be done by

unskilled labor and light equipment.

(2) Effectively designed, a FTB can reduce wave height

and prevent facility damage in the sheltered area behind the

structure.

(3) Location and size can be modified to improve wave

damping characteristics for a coastal zone.

(4) The FTB can be used in some regions where conven-

tional bottom resting breakwaters are not feasible because

of soft bottom, deep water, or sediment transport problems.

(5) They enhance biological resources in a localized

area by providing an artificial reef for organisms.

(6) Their low profile in the water does not inhibit

the scenic values of coastal areas.

(7) Currents are not impeded by a solid barrier. There

are no stagnation problems common with conventional breakwater

design.

(8) Compared with rock, wood, or metal breakwaters,

-45-

FTB's are of less physical hazard to boaters.

Their disadvantages include:

(1) Maintenance requires time and money not typically

invested in conventional breakwaters.

(2) The breakwater cannot be moored year-round in

coastal areas where ice is prevalent.

(3) The breakwater does not provide the degree of

wave protection of conventional bottom resting structures.

(4) It can be a hazard to navigation and a source of

liability if not properly marked.

(5) If the longshore transport is significant in a

predominate direction, a FTB could produce negative downdrift

impacts.

(6) The FTB can only be used in a sheltered area

where waves do not exceed three feet with a long wave period.

The design is in a test and demonstration mode. The

relative past success of the structure is an encouragement

to researchers looking for the 1ow-cost alternative to

expensive shore protection schemes. It is offered here as

an alternative to the rigid, bottom resting breakwater

concept.

Jetties

A jetty is a structure extending into the water to direct

and confine river flow into a channel and to prevent or reduce

-46-

shoaling of the channel by littoral drift. It is typically

employed at inlets in connection with navigation improve-

ments.

Jetties and groins are similar in that they are both

built parallel to shore and function to interrupt the

littoral drift. The distinction is in the purpose of

construction, The jetty is designed to prevent deposits in

the lee of the structure while the groin is built to encour-

age deposits on the updrift side. Generally, the jetty is

much larger than a typical groin. There is only one true

jetty on the open coast of Erie County, located at the mouth

of Walnut Creek. Constructed by the Pennsylvania Fish

commission, it is of rubblemound construction and designed

to keep.an open channel for the boat launch facilities in a

man-made turning basin located 200 meters from the mouth of

the stream.

Jetties are not constructed as shore protection works.

They are mentioned here to prevent further confusion about

terminology as applied to shore structures.

-47-

IV. Shore and Beach Stabilization Techniques Which Clos ely
Approximate,the Natural Processes

Beach Nourishment and Conservation of Natural Beaches

Beach restoration and nourishment is accepted as a

structural alternative in erosion prevention since large

quantities of sand are moved about using heavy equipment.

The function of the natural beach was discussed at the

beginning of this section. Beach restoration and nourishment

projects are designed to approximate natural beach conditions.

Because of high utility in dissipating wave energy, a properly

maintained beach affords maximum protection for the adjoining

backshore.

When conditions are suitable for artificial nourishment

long reaches of shore may be protected by this method for a

relatively low cost per foot of protected shore (Shore

Protection Manual).

It should be noted that the cost is low compared to

breakwaters or seawalls. Beach nourishment for the individual

property owner can be expensive and unlikely to be maintained

over time. Artificial nourishment is a "quick fix" solution

to the major cause of most erosion problems--a deficiency in

natural sand supply.

Beach nourishment is an increasingly preferred adjustment

because it involves minimum interference with beach dynamics

-48-

and can be accomplished with little ecological disruption and

can quickly produce a usable and protectiver beach (NOAA, 1976).

Conservation of Sand

"Experience and study have demonstrated that sand from

dunes, beaches, and nearshore areas is the best material

available naturally in suitable form to protect shores"

(Shore Protection Manual).

Inventories of submarine sand supplies and improvements

in dredging technology have increased the prospect of contin-

uous beach nourishment from offshore sources (NOAA, 1976).

If sand is generally available in quantity, protection

of the shore is greatly simplified. However, large areas of

coast no longer receive large amounts of sand by natural

processes. It becomes apparent that sand, as a resource,

must be conserved by preventing losses of sand offshore and

by discouraging excess entrapment along the shore.

Beach nourishment projects offer distinct advantages:

(1) It is aesthetically pleasing as it preserves the

beach in a natural condition.

(2) It benefits rather than damages the shore beyond

the immediate problem area.

(3) It can provide immediate short-term protection.

There are some disadvantages. They include:

-49-

(1) The nourishment concept requires that beach nourish-

ment be continued indefinitely.

(2) Supplies of sand reaching the downdrift shore can

produce intermittent instability.

(3) Where littoral currents are active, the method can

be impractical and expensive.

Beach nourishment, if carried out properly can be an

effective means of shoreline erosion control. A commitment

must be made to provide constant maintenance in a highly

mobile beach environment. Where the littoral drift is less

active the technique can be used in conjunction with a groin

to maintain a beach without taking sand from the natural

system.

The Protective Influence of Vegetation in Steep Slope Conditions

The bluffs along the Pennsylvania portion of the Lake

Erie shoreline exhibit various rates of recession and erosion

in response to varying conditions. The factors influencing

these rates include:

(1) Undercutting of the bluff by wave attack accelerated

by high water levels,

(2) The movement of groundwater between layers of

permeable and impermeable layers,

(3) Runoff from shoreland area as sheet flow, from

drainage ditches, septic tank outfalls, etc.,

(4) Sheet runoff on-bluff surface,

-50-

(5) Soil creep,

(6) Raindrop impact, and

(7) Frost action.

The role of vegetation in retarding the relative rates

of erosion and/or recession is to delay the movement of water

in the system. It should be noted that in the case of internal

stress (slope failure), no amount of vegetation on the bluff

face will prevent this falure. An example would be the

movement of groundwater exiting as a spring line somewhere

on the slope. The weakening is internal and slumping will

occur carrying any vegetation with it. Another instance

involves undercutting of the bluff by wave attack. The bluff

becomes oversteep and slope failure occurs. Assuming no

protection is planned for the base of the bluff, noamount

of vegetation will prevent erosion. (See Figure 19)

The rate of groundwater flow can be slowed by a dense

vegetative cover in the area behind the bluff crest. The

plants act to retard the infiltration of water thereby

minimizing the impact on the bluff face. Ideally, a strip

of vegetation should remain as a buffer along the entire

bluff line. If new plantings are to be mad e, it should be

recognized that the bluff will recede and sufficient width

be provided to guarantee maximum benefit through time.

In the case of three (3) through seven (7) above, each'

factor can be reduced as to impact by proper vegetative

0 V\

-52-

management. In each case the vegetation acts to slow the

movement of water.

The role of the vegetative root mat at theimmediate edge

of the bluff should no t be underestimated. On-site examina-

tion shows the retention qualities very well. It has been

pointed out that often mature trees can produce a negative

impact. As the root structure is undermined by movement on

the bluff high winds can topple the tree taking several cubic

yards of material with it. In such cases it would be wise to

cut the tree before this can occur. If the species is of the

variety that produces shoots from the main trunk the cutting

can be made several feet from the ground in the hope that

removal of the crown will prevent toppling while the roots

remain alive to continue offering a measure of retention.

The recommendations made by the State of Michigan as

to the role of vegetation and the various species considered

important are as follows:

Tree cutting and removal of other vegetative cover
along the shores of the Corridor should be regulated to
protect scenic beauty, control erosion, and reduce
effluent and nutrient flow from the shoreland.

Many plants, densely root and densely spaced, can
aid in shore stabilization, particularly in noncritical
erosion areas.

Native, established vegetative cover should be
maintained where it exists; additional plantings should
be made to increase density where shown to be beneficial
for purposes of either shore stabilization or scenic
enhancement.

-53-

New cover should be established on exposed,
erodible shorelands in conjunction with structural
protection measures, or alone.

Plants considered important in terms of shore
stabilization along the Great Lakes include:

Native Species

Pioneer Zone

Ammophila breviligulata (beach grass)
Cakile endentula (sea rocket)
Calamovilfa longifolia (dune grass)
Ammophila breviligulata (sand reedgrass)

Scrub Zone

Prunus serotina (black cherry)
Salix syrticola (dune willow)
Corrus stolonifera (red osier dogwood)
Juniperus horizontalis (creeping juniper)

Forest Zone

Arctostaphylus uva ursi (madrona)
Populus deltoides (cottonwood)
Populus tremuloides (quaking aspen)

Exotic Species

Pioneer Zone

Agropyron dasystachyum (hairy wild wheat)
Agropyron species (wild wheats)
Artemisia species (wormwood)
Elymus arenarius (sea lymegrass)
Pteridium species (brachen fern)

Scrub Zone

Cystisus species (brooms)
Eleagnus srgentata
Erica species (heaths)
Populus species (aspens and poplars)
Pyrecantha species (firethorns)
Rosa species (roses)

Forest Zone

Prunus virginiana (choke cherry)

-54-

The manner in which shore cover is maintained,
removed, restored, or reinforced is also important in
aesthetic terms. Thinning out of trees is preferred to
clear-cutting. Clear-cutting or severe thinning should
not be allowed on highly erodible soils and slopes.

Shore cover regulation should extend to a strip
depth which reflects both the vegetative type and the
resource priority status of the shoreline. A minimum
depth of 50 feet* in conifer--dominant regions, and 100
feet* in deciduous dominant regions, should be main-
tained in General Use Districts to ensure sufficient
screening of structures and accessories. In Conserva-
tion Districts, the minimum depth dimensions should be
150 and 300 feet respectively. [In "hardship" cases,
property owners could be allowed exceptions on the
condition that a state-approved or locally approved
landscape plan be first accepted.]

Where done, clear-cutting should not extend to
more than 30 percent of the length of the shore strip
of any property frontage.

Cutting that is more extensive than the 30 percent
limit should be executed only in accordance with an
approved cutting plan that would ensure suitable screen-
ing of structures and accessories.

Natural shrubbery should be preserved as far as
practicable, and where removed, replaced with other
vegetation equally effective in preventing erosion
and preserving natural beauty.

Tree seedlings and shrubs should be made available
at a nominal cost to shoreland owners to encourage
restoration or reinforcement of shore cover.

The planting of new trees and shrubs as screens
should utilize species, planting patterns, and plant
heights that are compatible with the structural
images they are intended to disguise.

(A Plan for Michigan's Shorelands)

*Greater widths may be necessary in stands of old,
tall trees because of proneness to wind topping.

-55-

Summary of Key Points in Considering Vegetation (Clemons,
GLBC)

(1) Shallow rooted.grasses provide a favorable habitat

for the establishment of deeper rooted shrubs and trees.

(2) Vegetation removes water from bluff areas through

uptake and transpiration.

(3) Roots hold soil particles in place while deeper

roots of woody vegetation prevent slipping of soil layers.

(4) Vegetation slows runoff and acts as a filter to

catch sediment.

(5) Vegetation can improve the visual quality of a

shoreline.

(6) Vegetation slows w ind velocity and traps wind-blown

sediment.

(7) Vegetation absorbs the energy of falling rain.

(8) Vegetation helps to maintain absorptive capacity

of the soil.

(9) Vegetation can reduce frost penetration.

Vegetation will not:

(1) Stop erosion due to wave action, or

(2) Control deep-seated movements associated with bluff

failure.

There are few, if any, proven and guaranteed vegetative

shore protection techniques that can function independently.

-56-

Combining vegetation and structural alternatives to stabilize

bluffs should definitely be encouraged.

The preceding information in this section has dealt with

the major ty pes of shore protection techniques. The following

information deals with the types of materials being experi-

mented with to implement traditional construction techniques.

The following will be discussed;

(1) The use of fabrics as filter materials,

(2) Sandbags and longard tubes,

(3) Gabions, and

(4) Miscellaneous (rubblemounds, rock-mastic, concrete

blocks, planter box revetment).

This section is intended to give examples of some new

techniques and is not a review of all the ideas being

suggested as shore protection devices.

Fabric

Apart from the use'of fabrics as containment devices

described under sandbags and longard tubes below, fabric has

general utility when combined with other materials as a

filtering device. A woven sheet of polypropylene yarn, for

example, permits water, under pressure of wave action, to

pass through but prevents fine particles of sediment from

was hing away. The applications include the following:

(1) Separation - used to create zoning of materials or

-57-

separation of materials by size;

(2) Reinforcement - slope stabilization, retaining wall

construction, soil containment systems, and concrete reinforce-
ment; (3) Drainage - internal drai .nage in earthen dams,

drainage behind retaining walls; and

(4) Erosion control and/or prevention (Welsh and

Koerner, 1979).

Generally, the -fabrics are woven nylon, polyester,

polypropylene, polyamide, polyethelene, or combinations of

the above. The resultant cloth is anywhere from 3-151 mils

thick and are priced from $.15 per square foot.

Sandbags and Longard Tubes

A longard tube is constructed in layers. Essentially,

a woven material is coated with a polyvinyl sheeting. The

tubes are 42" to 69" in diameter and are available in varying

lengths. Sand is pumped into the bag as a slurry with-the

sand being trapped at the other end by the use of a filter

material. The result is a semi-rigid structure that can be

used in a variety of shore erosion prevention applications.

Some key points offered by Armstrong and Kureth (1979) are as

follows:

(1) It is difficult to generalize on the applicability

of a wide variety of potential sites.

-58-

(2) The use requires a s ubstantial period of time over

which the structure must be closely watched-to gauge its

performance and effective ne-q.

(3) It appears to have enough favorable observation to

now be defined as a concept that has moved from "unusual" to

some respectability.

(4) The longard tube is definitely low cost (approxi-

mately $30 per foot of protection) with respect to more

familiar concepts.

(5) The device has reasonable endurance. Vandalism

(slashing the bag) seems to be a specific problem mentioned

by many-researchers.

(6) A structure of longard tubes can be constructed in

a relatively short period of time.

(7) Placing of a longard tube is not a do-it-yourself

project though it can be done easily by a contractor equipped

for the job. (See Figure 20)

Three applications of the longard tube as part of the

Shore Erosion Control Demonstration Project are described

below.

In an experiment at Empire, Michigan some shifting of

the bags was noted. Also, a single tube was unable to

withstand wave forces.

At Lincoln Township, Michigan longard tubes were used to

construct a groin at a cost of $57 per foot of protection.

_60-

Problems encountered included a lack of sufficient tie-in

with the shore and some settlement. It was'judged to be a

good but temporary solution as it performed its basic function

of accumulating sand behind it but was not expected to with-

stand wave forces beyond a two to three-year period.

A revetment of longard tubes was built at a Moran,

Michigan beach at a cost of $57 per foot of protection.

Again, shifting of the tubes presented some problems although

there was some positive effect in protecting the bluff.

Experimentation has shown (Brater, 1974; Gutman, 1979;

Machemehl,, 1977; Armstrong, 1976) that giant sandbags may be

used with a measure of success. Similar to the longard tube,

the bags measure 101 x 51 x 1.51 and hold 2.5 cubic yards

of sand. Marketed under the name of "Durabag" and "Sand

Pillow" they are being used for groins, low cost revetments,

or as a supplement to traditional construction techniques.

With an economic life of two years, they compare favorably

with other, low cost techniques. For example, a sand bag

groin can be built at a cost of approximately $40 per foot

of protection and a revetment could cost as little as $12

per foot of protection. One method used was some creative

stacking to help attenuate wave energy over an irregular

surface. (See Figure 21)

#jjk
It
'@A_ lit P33
51 "A"

,l3v

-63-

Some problems encountered in placement include filling

the bag... finding the right materials offsite and, as in the

case of the longard tubes, vandalism.

An experimental revetment was constructed at Moran,

Michigan using sand bags. For some time after construction

researchers claim it was working to protect the shore and

the bluff behind it (Brater, 1974).

If the property protected is valuable, sandbags placed-

and maintained over two to three year periods cou ld offer

low cost protection to a shore with a mild wave climate.

Longard tubes, grout filled bags, and giant sandbags
have been tested at Presque Isle State Park. 'As an experiment

the configurations used failed to protect the eroding shores.

Because of the severe wave climate the structures were easily

overtopped and flanked. It is interesting to note, however,

that many of the bags are essentially still in place with a

minimum of shifting and/or settling.

Gabions (See Figure 23)

Gabions are wire mesh baskets approximately 31 x 1.51 x

1.51 in size holding up to five cubic yards of material. The

material placed in them varies from natural stone to concrete

rubble. As in the case with all such structures, the materials

should not come from the shore to be protected but rather

AbP1

7n:
.:k

Gabion groin, 3
miles South of
Port Sanilac. Mi.

23,

-65-

from offsite landward locations. The baskets, in various

arrangements can be used to construct groiris and revetments.

The advantages of gabions include:

(1) Property owners can construct them themselves if

suitable materials for filling them can be found and

delivered to the site.

(2) They are durable, yielding to some pressures but

essentially maintaining shape and position.

(3) They are permeable, retaining sediment while allow-

ing water to pass through.

.(4) The coarse texture assists in attenuating wave

energy.

Gabions can be an effective, low cost, tem porary means

of retarding shore erosion. Placed in front of existing

structures (bulkheads, revetments, or groins) the gabion

assists in attenuating wave forces and reinforcing the

existing structure.

Miscellaneous Structures and Techniques

Rubblemound Structures and Rip Rap

Rubblemound structures have been increasingly used as

a low cost alternative to more rigid structures. They are

not used by individual property owners because of the diffi-

culty and expense of handling large rock but have utility in

major construction works such as,breakwaters and large groin systems.

-66-

A large amount of engineering data are now available as

a result of concentrated effort by researchers interested in

their utility. However, major and costly failures in rubble

mounds continue to occur (Edge, 1976). According to Edge (1976)

the following are indicated

(1) Structures built in deep water should question the

traditional methods of design and construction.

(2) Use of large armor units indicate a need to recon-

sider criteria by which damage to structures is defined in

model studies.

(3) Hydraulic model tests should also model actual

strength of the individual armor units.

(4) Constant monitoring of the structure should

determine early signs of structural failure.

Despite the fact that rubblemounds are not generally

used by the individual property owner, the concept should be

investigated by municipalities as an alternative given the

cautions expressed abo%@e.

Rip rap rock revetments are seen with increasing frequency

as a shore protection device. As with the rubblemound

structures, the individual property owner cannot consider it

due to the large size of the material used with the consequent

cost. They are successful if carefully engineered with the

stone size in keeping with the expected wave forces. Rip rap

can be used in association with rigid structures as a first

-67-

line of defense to reduce scouring at the base. In use the

rip rap revetment should be constructed in keeping with the

previous discussion on revetments.

Rock Mastic Combinations (See Figure 24)

Typical structures employing this technique would

include groins and revetments. Mounds of rock 6" to 12" in

size are covered with asphalt as a paving material.. They

should only be used by experienced asphalt materials

specialists with the heavy equipment needed for installation.

An experimental rock mastic revetment was constructed

at Michigana, Michigan as part of the Erosion Control

Demonstration Program. According to researchers (Brater,

1974) the structure performed well during the first year

stopping erosion in that area and showing great promise as

an erosion control device.

Planter Box Revetment

The planter box concept involves a steel reinforced,

locally precast, site assembled massive concrete box. The

technique is based on the principle of terracing. The boxes

are placed on a 30-35% prepared slope and underlain by a

filter fabric. The boxes are filled with soil and plant

growth is encouraged. It would appear that the concept has

some utility on a low wave climate shore.

JOT POURED
ASPHALT MASTIC
LQZO-q1F7
60 POUND ROCK
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-69-

Concrete Building Blocks

A structure assembled from concrete blocks can be

expected to collect sediment as part of their function.

However, most configurations cannot be expected to protect a

shore against any wave greater than one meter. They are

easily overtopped by higher waves and are easily undermined

by scour at the base. Advantages include:

(1) The materials are readily available at low cost.

(2) They can be handled easily by the individual

property owner and can be installed without the need for

skilled labor.

(3) The installation does not limit recreational access.

(4) In some cases, vegetation can be established on the

revetment face (Giles, 1977).

Others

other materials that have been experimented with include

modifications of the traditional timber crib design, zig zag

panels designed to interfere with wave energy, preformed

concrete rings, dolos, etc. Structures built of such-

diverse materials have some utility and may function as

designed in-areas where a more traditional design may be

successful but where economics dictate a lower cost alternative.

The above has been a general examination of many types

of structural alternatives. Further information is available

-70-

in a variety of sources and specifically in the U.S. Army,

Corps of Engineers' publications Help Yourself and the.Shore

Protection Manual. These materials should be consulted for

detailed descriptions and applications as well as engineering

design "do's and don'ts".

Non-Structural Alternatives
For Shore Erosion Protection

There are many alternatives to building a structure to.

reduce losses due to erosion. They should be given serious

consideration before the expense of complicated shore

structures is incurred. They include:

A. Institutional Arrangements

1. Structural setbacks and zoning

2." Stormwater management

3. Insurance

4. Acquisition

5. Relocation

B. Private Arrangements

1. Site Planning

a. Vegetation Management

b. De-watering

c. Runoff control

Each of the above points will be covered illustrating the

key concepts of each.

-71-

Institutional Arrangements: Structural setback requirements
and Zoning

"Development of land on the top of the bluffs has

resulted in acceleration of the natural erosion process.

Development activities result in the removal of soil

stabilizing vegetation, alteration of the surface drainage

patterns, and increased impacts from runoff and wave action"

(OSPD, 1978).

ItTo protect banks and bluffs and minimize hazards, (the)

community will need to enforce setbacks and controls on such

factors as water seepage and physical alteration" (Conservation

Foundation, 1980).

Development should be set back from the unstable bluff

areas so that an erosion prone zone adjacent to the bluffs

is maintained free of development. Structures should not be

allowed to diminish the scenic quality of the bluffs, and

public access to the bluff areas should be assured. Vegeta-

tion at the bluff edges*should be maintained, and land

disturbing activities should be discouraged (OSPD, 1978)..

Crowding of the water's edge and improper construction,

a frequent cause of excessive property damage, can be

controlled by the establishment of set back lines and building

code restrictions (Environment Canada, 1973).

-72-

Through.the Coastal Zone Management Program, Pennsylvania

.has successfully passed enabling legislatioh providing for the

establishment, at the municipa 1 level, of a Bluff Recession

and Setback Act. -As a result, the local governments involved

have created zoning ordinances which establish a recession

line with a prohibition on construction lakeward of the line.

These ordinances have been established after preliminary

studies revealed the extent of the hazard (Knuth, 1974). Any

ordinance of this nature, to be successful, must be based on

scientific evidence of its necessity and should be imposed

only after proven.

A community may assure that future development is set

back--not just from the present edge, but ideally from an

anticipated future edge (Conservation Foundation, 1980).

Establishing a setback presents four principal problems:

(1) To calculate a setback requires extensive data

collection.

(2) There may be a need to re-evaluate setback distances

as changing physical phenomena dictate.

(3) What is the optimum time over which erosion can be

expected to cause bluffs to recede. Should it be 50 years?

(4) What should be done about non-conforming buildings

and unbuildable lots?

-73-

The municipal ordinances in Erie County cover these key

points. In particular, variances are provided for certain

conditions. It should be stressed, however, that liberally

granting variances may render the ordinance ineffective.

Not present in the majority of the ordinances are provisions

for protecting the bluff face.

Specifically, the ordinances should be expanded to:

(1) Discourage activities that physically alter the

face or toe of banks and bluffs.

(2) Prohibit removal of vegetation and excavation that

increase the chance of bluff failure.

(3) Prevent removal of rubble or debris from the toe

area. Such removal fosters increased erosion of the base.

(4) Prohibit structures of any type on the bluff face.

Proper setback ordinances have two distinct advantages:

(1) If the area is kept in a natural or semi-natural

condition, slope stability is fostered, and

(2) Proper maintenance of the bluff and proper setbacks

landward will reduce the need for structural measures at the

bluff toe.

In addition to bluff recession, there is the continued

problem of shore erosion. There is no provision in the Bluff

Recession and Setback Act for ordinances covering the area

between the bluff crest and lakeward of the toe of the bluff.

-74-

Such an ordinance could be established at the municipal level

and should provide for the following elements:

(1) Locate all structures away from the beach slope

area. If there 4S insufficient space between the beach

backshore and the toe of the bluff, construction should be

prohibited.

(2) Avoid removing sand from parts of the beach-system,

including the shallow nearshore zone.

(3) Maintain natural beach processes by discouraging

structures that adversely affect littoral drift (Conservation

Foundation, 1980).

Non-Structural Alternatives: Insurance

Up-to-date information related to insurance programs

covering losses due to erosion in the Great Lakes comes from

the Great Lakes Basin Commission's position paper on the

Coastal Hazards Element of the comprehensive plan (GLBC, 1980).

"Amendment of the erosion hazard insurance provisions (sections

1302(g) and 1370(c) of the National Insurance Act of 1968, as

amended, is needed in order to eliminate the insurmountable

technical and administrative problems that have resulted since

1973 from attempts to implement an insurance program for

coastal erosion."

And further;

"FEMA should promulgate specific standards for payment

of erosion related claims, and make the strongest possible

-75-

effort to insure that notice and complete understanding of

these standards reach all involved parties."

Non-Structural Alternat ives: Acquisition, Relocation

The literature is mixed with regards to relocation as

witnessed by the following.

Due to the prohibitive costs and significant political

and social disruption, acquisition of entire coastal hazard

areas is not feasible as a major means of coastal hazard

mitigation (McKinney, 1980).

While according to NOAA (1976), "in inany places, either

acquisition or relocation can be a preferred alternative to

structural protection," and,

"Directed abandonment or relocation of established uses

is beyond the realm of social and economic reality" (Jones,

1978).

Clearly, removing an endangered structure, with conse-

quent government acquisition, is a proven method. However,

an examination of the financial costs involved place the

concept beyond the means of most municipalities who, usually,

have their hands full protecting what they already have in

the shore zone in the way of public lands and/or structures.

-76-

Non-Structure Alternatives: Private Arrangements

A companion report will deal extensively with the issue

of stormwater management and the role of groundwater in caus-

ing erosion and recessional losses and will not be dealt with

here. A publication of the Great Lakes Basin Commission,

The Role of Vegetation in Shoreline Management, discusses that

issue extensively.

Work Element 4.b.

THE CAUSE AND EFFECT RELATIONSHIP
BETWEEN EROSION CONTROL STRUCTURES
AND SUBSEQUENT DOWNDRIFT EROSION

General Introduction

This section should, properly deal with the impact of

shore structures on physical forces at work in the beach zone.

The literature strongly suggests the cause and effect pheno-

mena between the two. The following is a summary of current

thought as well as an investigation into the kinds of side

effects that can be expected . In some cases the position

taken is strong. "In spite of mounting evidence that we are

dead wrong, we persist in the practice of putting rigid

barriers in the way of natural forces. We insist on occupying

land that needs to move'to survive" (Speight, 1975).

Others suggest that proper planning and design can miti-

gate the impact but no serious researcher denies that the

construction of any barrier will produce a negative effect

somewhere in the system.

The shoreline of Erie County, Pennsylvania is undergoing

development, largely in the conversion of farmland to residen-

tial use. This changing land use has brought the homeowner

into direct conflict with the natural forces. Land that has,

historically, been developed is now facing increased threats

due to persistent high lake levels. The solution is generally

an attempt to reduce the threat by placing barriers on the

-79-

shore. These attempts to stabilize a particular site usually

compounds the problem offsite. We are learning that these

devices are, in the long run, destructive of the very features

we mean to preserve. (See Appendix II)

Researchers generally agree that the -shore is a dynamic

system undergoing constant cycles of erosion and accretion.

It is also agreed that natural beaches are the best defense

against loss of property. During the erosion phase of the

cycle the placement of any structure will destroy the flexi-

bility of beaches to respond to changing conditions. "There

is inadequate information to assess the coastal system as an

integrated system of sediment erosion, transportation and

deposition operating over an extended peribd of time" (McGill,

1980). "The problem of shoreline damage due to littoral

barriers is now widely recognized and must be considered in

the planning of all coastal structures (Roellig, 1978).

The key to understanding the cause and effect relation-

ship between erosion and subsequent impact is in understanding

the nature of the longshore transport system. Longshore

transport is dependent on wave climate, beach profile, shore-
line configuration, sediment budget,'currents, offshore

bathymetry, and existing shoreline structures with waves as

the primary driving force (Noble, 1978).

The Pennsylvania Coastal Zone Management Program, through

extended research, is attempting to look at some of these

-80-

parameters and will, as a result, be in a better position to

make recommendations concerning the placement of shore

structures. Essentially, we now know that sand, or the lack

of it, is of prime importance. Any sand taken from natural

processes is a loss to downdrift users and-erosion of those

beaches follows (Parker, 1980). Although there are many

examples of man's intervention in coastal processes .... man's

critical modification of the balance of sediment and depletion

of the supply of sand to the beaches of the world has reached

a critical state (Inman, 1978). This is as true for Lake Erie

as it is for the Atlantic or Pacific shores.

The historic development of barriers (usually groins)

in the Erie County Coastal Zone has significantly reduced the

amount of sand available and has created a redistribution of

sediment to the benefit of the builder and to the detriment

of others. Any structure placed in the water will have some

effect, however minimal, on the wave and current patterns with

which it interacts (Kureth, 1980). Structures such as groins,

built perpendicular to the shoreline into the surf zone will

obstruct the longshore current resulting in the depositio n of

sediments on the updrift side of the structure (Terich, 1975).

Any artificial structure that produces a local accretion of

sand by interrupting the transfer along the coast will cause

a corresponding local erosion just downcoast from the area

of accretion (Inman, 1980).

Impacts will vary with the type and size of the structure

built. Simison et al (1978) offers five parameters for evalu-

ating the impact of structures.

(1) The length of the structure relative to its

offshore distance,

(2) The incident wave length relative to the offshore

distance of the structure,

(3) The depth of water at the shoreward face of the

structure,

(4) The incident wave vector of wave approach at the

structure and the resultant wave shadow in the lee of the

structure, and

_(5) The position of the structure relative to the

active littoral zone.

Unfortunately, the usual structure is placed bearing on

a variety of factors having little relationship with the

above. Generally a structure is evaluated by the property

owner based on a perception of the success of a similar

structure nearby or is promoted because the nearby structure

is having a negative effect on his property. In this case

the problem is merely being passed off to the next downdrift

owner.

The following section is a discussion of.the specific

types of structures commonly built and the direct and indirect

impact on the total reach.

-82-

Groins

"It is well known that groins constructed on coast

stretches with a longshore material transport cause a reduc-

tion or cutoff of the transport in the beach zone (Mikkelsen,

1977).

By far, the most dramatic coastal interference occurs

when man interrupts the longshore transport of sand by the

construction of .... groins"(Inman, 1978).

Groins by design are intended to entrap sand moving in a

shore parallel direction. The rationale is that such sand

will act as a buffer causing waves to lose energy as run-up.

Storm waves will, of course, serve to remove the accumulated

sand in an offshore direction. The sand lost off shore will

in turn be replaced by the longshore transport system. By

design, most groins function exactly as intended. The

problem, as stated above and re-stated by any number of

researchers is that the sand entrapped is prevented from

reaching the downdrift beach. The result is a starved

sediment budget downdrift with consequent erosion.

The extent of the d'owndrift erosion depends on the

efficiency of the groin or groin system in trapping sand and

the amount lost offshore as the sand passes around the end

of the groin (Everts, 1979). Both of the above serve to reduce

the volume of sand reaching the downdrift beaches.

-83-

Everts (1979) makes a very valuable comparison between

a shore without groins and one with groins.- The comparison

is as follows:

Coast without groins:

(1) Sediment transport along a coast is a combination

of onshore or offshore and longshore movements.

(2) If a net longshore transport of sediment exists,

this movement is probably occurring in a complex zig zag

pattern with a downcoast component.
(3)* Net losses from, or gains to, the beach from the

offshore region are usually small in comparison to the net

longshore transport rate past a point on the beach.

(4) Shore parallel movement occurs on the foreshore,

in the surf zone, at the wave breakpoint and on the existing

longshore bars.

Coast with groins:

(1) For sand to pass by a groin system in a shore

parallel direction, it must move seaward of the groin ends.

(2) The sand moves about of mid-point axis that is

further from shore, in deeper water, less on longshore bars.

(3) The consequences of this seaward deflection of the

littoral zone will likely be a decrease in the transport rate

and an increase in offshore deposition rate off the groin

system.

In other words,the groin forces the river of sand

-84-

offshore where some is lost to the deep and is thus unavail-

able to the shore downdrift.

The following should be kept in mind by those proposing

construction as well as by planners and permitting agencies:

(1) Groins which capture all littoral drift should not

be constructed since they aggravate or encourage beach

erosion.

(2) Downdrift beaches will recede until the groins.are

filled and sand by-passing occurs.

(3) A series of groins will take longer to fill prolong-

ing the period during which downdrift shorelines are exposed

to erosive forces (Shanks, 1978).

(4) If it can be determined that problems created by

construction outweigh any expected benefit they should not

be permitted.

(5) Property owners on the downdrift side are usually

forced also to construct groins lest they lose their beach

(Terich, 1978).

(6) Even with an adequate supply of sand in the system,

downdrift beaches may erode while the updrift side is filling.

(7) Updrift sides of groins should be artificially

filled and artificially maintained to reduce amount of lost,

naturally occurring sand.

(8) Some erosion downdrift will always occur (Sanko,

-85-

In summary, groins serve to redistribute sand in the

system by trapping it on the updrift side thus diminishing

the amount downdrift. One property owner with a structure

will create a chain reaction whereby downdrift property

owners will be forced to construct protection measures,

usually another groin. Unfortunately, there is not enough

sand in the system to fill them all and the majority do not

function as designed. A starved groin is generally lost to

scour, flanking, or breaching.

Groins should be discouraged as a structural alternative

unless arti ficially filled and maintained.

Bulkheads, Seawalls, Revetments

Key Points:

(1) The presence of a seawall, bulkhead, or revetment

on a shore often promotes erosion of the foreshore in front

of the structure caused by waves reflecting off the face of

the structure (Shanks, 1978).

(2) When built on a receding shoreline, the recession

will continue and may be accelerated on the adjacent s hores

promoting flanking (Shore Protection Manual).

(3) Attempts to reduce erosion by maintaining a static

shoreline by the construction of shore parallel structures

such as seawalls, bulkheads or revetments has resulted in

losses and damage to the beach systems and related resources

(McKiney et al, 1980).

86-

(4) During storms,,seawalls prevent landward erosion of

the natural beach profile. Typically, the natural profile of

the sections of beach without seawalls will erode during

storm conditions and establish a submarine bar offshore

which, in turn, provides protection by tripping the higher

waves and preventing them from reaching the beach (Walton,

1979).

(5) Any downdrift impacts related to the construction

of bulkheads, seawalls, and revetments comes from the fact

that the shoreline is now protected and is not contributing

sediment to the longshore transport system (Sanko, 19

Breakwaters

Key Points:

(1) A solid breakwater can decrease circulation, inter-

fere with waves and currents, and obstruct littoral drift

(Shanks, 1978).

(2) In the absence of wave action to move sand, it is

deposited lakeward toward the breakwater. The consequent

build-up serves as a barrier which also blocks the movement

of littoral materials producing an "end of groin field

phenomena" starving the downdrift beach. The segmented

breakwaters at Presque Isle State Park are a classic example

of this negative impact.

(3) Detached breakwaters produce only minimal impact

when the offshore distance of the structure is greater than

-8 7-

six times the breakwater length (Simison et al, 1978; Noble,

1978; Inman and Frautschy, 1965).

Jetties

Key Points:

(1) Nearshore currents can be disrupted; erosion and

accretion can occur locally in patterns far different than

pre-existing patterns.

(2) Jetties at stream mouths alter the rate of both

river outfall and interfere with the littoral current (Shanks,

1978).

(3) Sand is impounded at the updrift side of the jetty

and the supply of sand to the shore downdrift from the inlet

is reduced, thus causing erosion of that shore. The

Pennsylvania Fish Commission jetty at Walnut Creek is a

classic case of producing cause and effect.

Conclusion

It is apparent that any structural methodology designed

to reduce shore erosion will produce some negative effect or

impact. In a design analysis of a shore improvement project

provisions should be made to mitigate, to the extent possible,

any adverse impact.

For example, groin induced damage can be mitigated by:

(1) making groins permeable; the optimum design for permeable

_88-

groins would allow a sufficient amount of sediment into the

downdrift reach while continuing to provide protection, or

(2) by artificial beach nouris hment at the time of construc-

tion and as a continuing maintenance item.

Artificial nourishment is also useful to establish a

feeder beach to introduce sediment into the longshore drift

as a means of establishing beaches in front of bulkheads,

seawalls, or revetments and removing the threat of downshore

erosion as the result of construction.

Effects on adjacent lands should be considered to the

extent of providing the required protection with the least

amount of disturbance to currents and future land use,.

environmental factors, and aesthetics of the shore (Shore

Protection Manual).

Conflicts between human activities and physical shore-

line processes cannot be easily resolved resulting in:

(1) some coastal areas have become hazard zones where

the risk of destruction by wave induced activity or flooding

is high, and

(2) Areas have become artificially protected reducing

the risk of destruction but often altering the natural

coastal system causing extreme physical impact elsewhere in

that system (McGill, 1980).

Work Element 4.c.

DESIGN CRITERIA THAT MUST BE MET
TO PROVIDE AT LEAST A MEASURE OF
SUCCESS FOR EROSION CONTROL STRUCTURES

"Poorly conceived and improperly designed protection

projects function poorly at best" (Parker, 1980).

Before an approach can be rationally selected, the

problem must be identified and described, its cause deter-

mined, and an objective established.

(1) Why is the shoreline retreating?

(2) Is sand being lost to longshore transport or

offshore?

(3) Are losses due to updrift structures?

(4) Are such losses temporary or continuing?

(5) What is the value of property and/or structures to

be protected?

(6) Should wave energy be opposed or absorbed?

(Parker, 1980).

These are the question that should be properly answered

as a first step in the planning process. Most can be answered

by observing a particular site over a brief time. Making a

wrong decision at this stage will act to diminish the success

possibilities of the alternative chosen.

The next step is to involve a qualified engineer to

reduce the risk of failure by designing protection for the

_91-

conditions at a specific., problem area. The design of shore

protection works is complex and.good engineering principles

must be followed.

An individual contract may or may not have engineering

expertise at his disposal. Most contractors design their own

structures and have little knowledge of forces or processes

involved along the shoreline.

The second phase in planning should consider the

following categories of information:

- Function

- Site Characteristics

Engineering and Economic Factors

Construction Material

Expected Life Span

Physical Impacts

Review of Structural and Non-Structural Alternatives

1. Function

The function of the erosion control structure should be

clearly defined. The builder has a definite goal in sight,

whether it is the intent to trap sand or to oppose wave

forces, there is an express result in mind. This result

should clearly be compatible with the type of structure

proposed. The design of the structure should be in keeping

with the desired function. Over design will have direct

-92-

bearing on the offsite impact which must be kept at a minimum.

The design must be just enough to affect piotection.

If the express intent is for recreational beach, boat

launch facilities, or other non-protective use, the builder

should be discouraged from continuing through the planning

process.

2. Site Characteristics

the plan should contain a detailed sketch of the

physical location. Included in the sketch should be the

following:

(1) Width of beach,

(2) Beach profile (to a depth of 2 m),

(3) Nature of beach materials (fine sand, coarse sand,

gravel, cobbles, etc.)

(4) Condition and configuration of bluff, and

(5) Orientation from north.

In addition, some consideration should be given the

following:

(1) Hydraulic Considerations

a. Wind-predominate direction and force

b. Waves-to include the wave climate parameters
of height, period and storm frequency

C. Currents

d. Offshore bathymetry (presence of bars, etc.)

-93-

(2) Sedimentation Considerations

a. Type of sediment in transport

b. Rate of transport

C. Predominate longshore drift direction

d. Sediment budget

The above data are relatively easy to gather for an

individual site. Part of the coastal zone management educa-

tion function should be a brochure outlining the methodology

for site data collection. With this information as part of

the plan, some intelligent decisions can be made relative to

the suitability of a particular design.

3. Geograp4ic Prevalence

What is the nature and extent of other shore protection

structures in the area? Are they functioning as intended?

What is the probable impact of adding an additional structure?

4. Engineering and Economic Factors

Information on specific engineering design criteria

follow this section. In addition, the booklet, Help Yourself

(U.S. Army, Corps of Engineers): details the types of engineer-

ing information and procedures that should be considered.

The cost of the structure should be carefully weighed

against the most probable results. It has been found that

-94-

the cost of some structures far exceeds the value of the

property that would otherwise be lost during the expected

lifespan of the proposed structure.

The types of structures affordable by most property

owners are definitely in. the low cost category. Care should

be taken to ensure that low cost structures once built will

be properly maintained. Property owners should be h eld

responsible for clearing failed structures if they present a

navigation hazard or an aesthetic impact. The property owner

should be told the probable lifespan of the proposed structure

to avoid false expectations and financial disappointments.

5. Construction Materials

Inadvisable solutions for erosion problems include debris

dumped on bluffs, sewer pipes used as bulkheads, small sandbag

revetments, tires on poles, or randomly placed large concrete

blocks, small stone revetments, and low cost seawalls. Poor

methods usually offer no effective protection, are unsightly,

and may result in greater shoreline problems (Michigan

Seagrant).

Care should be taken to prevent "mining" of existing

beach for building material. Such removal or redistribution

will adversely affect natural physical processes and possibly

create more problems than their use as structural components

may solve.

-95-

6. Expected Life Span

No low cost structures will escape some damage from the

25-50 year frequency storm. As mentioned previously, the

life span of most low-cost structures is 2-3 years and

amount to temporary solutions that require constant mainte-

nance and repair.

Generally speaking, emergency protection may provide a

reasonable degree of protection through the first storm with

the degree of protection diminishing as additional storms

occur. Cost is a factor. It is estimated that the annual

cost of maintenance of emergency protection could well be

twice the initial construction costs (Corps of Engineers, 1972).

7. Physical Impact

Care should be taken in the development of a shoreline

so as not to aggravate the erosion process. Moreover, it is

imperative that each property owner realize the potential

consequences of his actions on adjacent properties as he seeks

to alleviate the erosion of his own land (Terich, 1975).

A full examination of cause and effect relationships is

offered in Section 2 of this report.

S. Review of Structural and Non-Structural Alternatives

The property owner should properly complete the planning

process by carefully reviewing his alternatives to ensure the

-96-

proposal is the best possible choice and that the structure

proposed answers the basic questions posed-above. Then, and

only then,should he be encouraged to enter the permit

seeking phase of construction.

The construction of new shore protection structures

such as jetties, groins, seawalls, bulkheads, or revetments

can be conditionally accepted in the permitting process if

they meet the following specifications:

(1) The structure is essential to protect water-dependent

facilities or heavily used public recreational beach areas

from erosion or to protect existing structures and infra-

structure in developed shorefront areas from erosion.

(2) The structure is designed to eliminate or mitigate

adverse impacts.on the local shoreline sand supply.

(3) The structure will not create net adverse shoreline

sand movement conditions downdrift, including erosion and

shoaling.

(4) The structure will cause minimum adverse impact to

living marine resources (McKinney, 1980).

Conversely:

(1) Sound compliance innovations will receive proper

considerations rather than automatic rejection.

(2) Every justifiable criterion will be considered.

(3) Imposed standards will be no more rigorous than

necessary.

-97-

(4) Requirements unnecessary for specific.situations

will not be imposed arbitrarily (Jones, 1978)..

Each criterio n should be thoroughly evaluated and

modified as necessary to be certain that it is consistent with

risk concepts proper for long term public purposes, long term

public shoreline needs, and-potentially critical environmental

protection needs (Jones, 1978).

Groins

Key Points:

(1) Two points expressed in the published literature

seem to be in agreement: (a) there is no standard or stock

groin design, and (b) the best groin spacing (for groin

fields) is somewhere between two and four times the groin

length (Berg and Watts, 1971).

(2) Because of its limitations, a groin should be used

only after a careful consideration of the many factors

involved.

(3) Groin length is a function of water depth or a

function of the di stance from the shoreline to the average

breaking point of plunging waves.

(4) It is suggested that groin length is a function of

the distance from the shoreline to the first inner bar.

(5) A permeable groin could cause the required deposi-

tion yet allow a significant amount of littoral drift to pass

through to alleviate some end of groin field effect.

-98-

(6) The interests of sound coastal management demand

that the benefits of groin construction, repair and removal

be carefully analyzed when and where possible (Wang et al,

1979).

(7) A high groin, extending through the breaking zone

for ordinary or moderate storm waves initially entraps nearly

all of the alongshore moving sand.

(8) Low groins (no higher than desired beach dimensional

high point) allows some sand to pass over the top.

(9) Groin dimensions depend on the wave forces to be

withstood, type of groin, and the construction material used,

(10) The length, profile, and spacing of groins in a

system, direction of wave approach, and the rate of longshore

transport are important functional considerations.

(11) Since most of the littoral drift moves in the zone

landward of the normal breaker zone, extending a groin

lakeward of that depth is generally uneconomical (Shore

Protection Manual).

(12) The design of a groin system should consider the

worst possible event.

(13) If conditions are not right or if the groin is

improperly designed, the erosion problem that prompted the

groin may not be solved (Sanko, 19

Seawalls, Bulkheads, Revetments

Key Points:

_91-

(1) It has been recommended that shore parallel

structures such as bulkheads,,seawalls and'revetments in

areas characterized by sandy beaches, be prohibited.

(2) Such structures impede the natural migration and

storm responses of sandy shores and result in significant

increased losses of natural beach areas (McKinney, 1980).

(3) The major considerations for structures of this type

are foundation conditions, exposure to wave attack, avail-

ability of materials and cost.

(4) other factors in planning and design are the depth

of wall penetration to prevent undermining, tie-backs or end

walls to prevent flanking, stability aga inst saturated soil

pressures, and the possibility of soil slumping under the

wall. (See Figure 25)

(5) Concave curved or reentrant faced structures are

the most effective for reducing wave overtopping.

(6) Factors to be considered in design include (a) use

and overall shape of the structure, (b) location with respect

to the shoreline, (c) length and height, (d) stability of

soil landward, and (e) lake level.

(7) Usually erosion may be expected at both ends of a

structure; wing walls or tie-ins must be provided to prevent

flanking and possible progressive failure of the structure

at the ends.

(8) Scour may be anticipated at the toe of the structure

as an initial short term effect. A rubblemound structure may

Or
AD

Initial shoreline position under
normal wove conditions

Shoreline due to storm or long
I e m erosion, without seawall
Shoreline- due to storm or long
term erosion,with seawall

Waves
Seawall of limIted length
Return Wall

4@1
ql@

PLAN VIEW

-101-

sink due to scour.

(9) As ageneral rule,:.the maximum ddpth of a scour

trough below the natural- bed is about equal to the height of

the maximum unbroken wave that can be supported by the

original depth of water at the toe of the structure.

(10) The placement of a rock blanket with an adequate

.bedding material lakeward from the toe will prevent erosion

at the toe resulting in a more stable structure.

(11) Buttresses can be added to bulkheads and seawalls

to provide additional support.

(12) Small groins are sometimes used in conjunction with

bulkheads and seawalls to help collect protective sand.

(13) A seawall is generally warranted only if reducing

wave overtopping is urgent. Examples might include road
protection, high density development, etc.

(14) The importance of any specific design used must

take into account the consequences of seawall failure as well

as the initial cost of the seawall. In the past, seawall

design has been governed by the amount of money the upland

owner has been willing to spend (Walton, 1979).

(15) A cooperative approach of neighboring properties

should be promoted for greater protective strength and the

elimination of flanking.

Artificial Nourishment, Protective Beachbs

Key Points:

-102-

(1) Determination of the predominant direction of

longshore transport and deficiency of material supply in the

problem area are important considerations.

(2) Determination of the composite average characteris-

tics of the existing beach materials or native sand in the

zone between the 30 foot depth and the bluff face should be

a priority.

(3) Evaluation and selection of borrow material for

initial beach fill and periodic nourishment, including the

determination of any extra amount of borrow material

required for placement based on the comparison of the native

beacfi sand and borrow material is critical.

(4) In addition, the following should be determined:

(a) beach berm elevation and width, (b) wave adjusted

foreshore slopes, and (c) feeder beach location (Shore

Protection Manual).

.I
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I SECTION THREE: MODEL EROSION
I CONTROL PLAN
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1(
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CONTENTS

(1) Introduction

(2) Basic Assumptions

(3) Management Alternatives

(4) Land Use Controls

(5) Required Information

(6) Statutory Authoritv

(7) Need for Plan

(8) objectives of the Ordinance

(9) SamDle Erosion Hazard Ordinance

(10) Summary Criteria: Model Ordinance

(11) Permits

(12) The Issue of General Permits

INTRODUCTION

"...Natural systems are dynamic; the survival of an

organism or an environment depends on its ability to change

in and around it. This knowledge has a way of burying

itself when we lay out a property line and a piece of earth

becomes real estate" (Speight, 1980).

Land use has been based on the concept that once land

is used for a particular purpose that change ceases and

attempts at change should be met head on. If we maintain

a value for land it is in the best interests of the occu-

pant to maintain stability as well and consider any

natural change as undesirable.

It must be accepted that erosion and coastal flooding

along the shores of Lake Erie are naturally occurring events

and that these events pose a hazard to the coastal zone

occupant. Attempts to reduce or eliminate erosion often

produce negative impact. A component of the eroded material

is the sand-sized particle that serves to protect the

beaches and bluff wherever it accumulates. To prevent

erosion of this material. is to deny some protection else-

where in the system.

Essentially problems in beach morphology are caused by

human actions. If nothing is built on the beach, there is

no "damage" if the beach changes shape. A beach will remain

7106-.

in various shapes as long as the process of natural replen-

ishment continues. It may shift with the seasons, yield

sand temporarily to storm erosion, slowly recede landward

with rising water levels or accrete seaward with natural

shifts in the flow of currents. Mobile and responsive, the

beach will remain over the years (conservation Foundation,

1980).

The main threat to any beach area and the bluff behind

the beach is development. To "freeze" this natural area in

space and time requires structural controls. Such controls

require management and thus present the case for erosion

control ordinances. When shore property is threatened by

erosion of beach or bluff, the first reaction is generally

to contrive a structural remedy. Such activity must be

regulated.

Wherever there is a discussion of the desirability of

public regulation' of private land use as a means of coping

with the hazard of extreme events, a specific statement

should be made of the probable effects of permitting con-

tinued development of that area. The majority of the

problems with coastal erosion are the direct result of

ignoring shore development in the past (NOAA, 1976). A

single response by a property owner to abate shore erosion

can produce a chain reaction of events as outlined in

Section 2

-107-

There are three subjects that bear upon shoreline

development (Jones, 1978). They are:

- Natural hazards

-The rights of the general public to develop shore

areas, and

-Restrictions and/or regulations concerning develop-

ment from the federal or state perspective.

What is needed for effective management is a strategy

whereby local authority can control construction of shore

protection works, the issuance of permits for structures,

the removal of sand and gravel from the beach foreshore and

any changes in the use of bluff slope, as well as continued

administration of the bluff set-back ordinance.

Two basic problems confront the coastal planner; (1) how

best to regulate land on which existing occupance is threa-

tened with damage, and (2) how to regulate unoccupied land in

hazard zones for which permission to construct is sought.

The sample ordinance developed here should, if adopted,

provide the municipality with regulatory authority to manage

construction of works in four zones:

- Beach Foreshore

- Beach Backshore

- Bluff Slope

- Bluff Crest and Landward to the Recession Line

_108-

BASIC ASSUMPTIONS

The following are basic assumptions that can be made

relative to hazard response by the community:

(1) Shorelines are a dynamic system, seldom at equi-

librium, and subject to great changes in morphology in

response to environmental conditions prevailing at any

particular time. The full impact of these changes is, at

times, difficult to perceive by casual observation. Only

when forces combine to produce a catastrophic event do

people become alarmed. The most serious events tend to be

periodic and at random places along the shoreline.

Occupance of the coastal zone considers the 99% of the

time when erosion is not accelerated. The lack of planning

for the 1% event has caused great concern and produced

various responses that are altogether too little and too

late. A major function of the planning ordinance should be

to alert the innocent or uninformed prospective occupant to

the 1% probability event.

(2) Natural changes are increasingly predictable and

quantifiable. Recent research activity sponsored in part

by the coastal zone management program has provided govern-

ment with technical dat-a related to cause and effect responses

in the shore zone. As more dollars are channeled into

research, the obvious beneficiaries are the property owners. As

_109-

awareness of.physical processes increases, the public has

been less likely to spend large sums of moi@ey on shoreline

development in hazard areas. The warnings that researchers

provide will have a positive impact on mitigating future'

loss potential.

(3) Natural changes are potentially endangering to

property. Each new permitted shoreline occupancy or exploi-

tation action, though incremental and seemingly negligible

in its significance to -the community, cumulatively increases

degradation of environmental quality in addition to property

or structure loss (Jones, 1978). Consideration of hazards

implies an added incentive for protection of the remaining

undeveloped shoreline.

The Coastal Zone Management Program has'given responsi-

bility to the municipality to maintain the shoreline in a

safe and healthful cond.ition. In addition, the municipality

should protect against costly shore erosion, control building

sites, control placement of structures, and regulate land

use. It should also act to preserve shore cover and natural

beauty.' This responsibility has been recognized generally

with respect to:

(a) Public Health

Development pressures on the coastal fringe create

a demand for additional services not now existing.

Specifically, the placement of leach fields and-septic

-110-

tanks in highly permeable sand layers adversely impacts

water quality in higher density development areas.

(b) General Welfare

The increased use of shoreland areas effectively

removes the opportunity for non-shoreland property

owners to access the coastal fringe.

(4) Potential endangerment is likely to imply public

costs that will vary according to the scale of the disruption.

A threat related to high density development is the likely

pollution rising from improperly treated sewage. This

generally involves great public expenditure by all levels of

government to install and maintain proper sewer and storm

water systems.

Ih addition, government must consider the loss of revenue

due to decrease in value of properties having appreciable

losses from erosion. A property owner seeking tax relief

from this decreased value can generally convince the courts

that such tax relief is indicated (Kerns and Scheid, 1980).

Despite the fact that increased development will increase the

tax base, expenditures for public works, sewers, culverts,

controlled drainage, etc., far exceed the amount collected.

Additional expenditures for solutions to the erosion problem

are often requested by the property owner.

Erosion losses of beach and bluff significantly decrease

both the amount and value.of shorefront property. As shore

erosion and bluff recession continue over time, the munici-

pality may expect a lower tax return while-still faced with

the problem of providing essential services.

(5) Governments should avoid or minimize costs in

keeping with the mandate to promote health, safety, and

general welfare.

(6) Governments may avoid or minimize public costs

by prohibiting or regulating development within known

endangered areas. Rather than planning for site specific

problems, regulations should be comprehensive, considering

erosion processes over the full length of the municipal

shoreline. Such an approach is more efficient and cost-

effective. Regulating the shore by ordinance and imparting

accumulated knowledge can increase understanding and respect

for the natural shoreline processes. This can minimize

future damage.

It can be forcefully argued that the strategy which

would yield the greatest long-term benefit to all of the

people .... would be a total cessation of development in

shoreland areas. Further development will diminish the

quality of the shorelands; with no further development, the

integrity of the natural shoreland ecosystem can be consi-

dered to the maximum degree" (A Plan for Michigan's Shorelands,

1973).

A regulatory policy is not likely to meet with popular

approval where restrictions on property or-on structures to

protect property combine with natural processes to diminish

value. Nor would they meet with acceptance where a particu-

lar reach is undergoing real estate growth. The regulations

would have maximum effect in promoting sound practices in

areas of new development. or in undeveloped areas.

While citizens may desire increased federal or state

funding for protection, they rarely welcome its side effect--

increased public access to "their" beach as a result of

governmental projects facilitating such access. Nor are they

likely to endorse strict regulations over what can and what

cannot be done on their property. A possible answer to this

dilemma is discussed in Section I.

-112-

MANAGEMENT ALTE RNATIVE S

From a review of pertinent literature two courses of

action dominate in attempting to mitigate erosion and

flooding:

(1) Engineering Techniques

(2) Management Techniques

The first seek s to meet the forces of nature head on

with works designed to 'keep the impact of natural events

from adversely affecting occupance of lands in the shore

areas. Such works should be regulated by the local govern-

ing authority to ensure proper design.

The second is an attempt to control development in the

coastal zone to remove as much threat as possible to struc-

tures and appurtenances.

Engineering techniques are designed to influence the

physical interface of land and water while management tech-

niques are intended to influence people in their use and

development of the shorelands (A Plan for Michigan's Shore-

lands, 1973).

The enactment of land use controls to mitigate erosion

hazards is a post W.W. II phenomena stemming from disenchant-

ment with traditional structural protection practices and

also from a growing need to resolve coastal conflicts (NOAA,

1976).

-113-

The adjustments to coastal erosion follow one of the

following:

(1) Adjustments to loss, including loss-bearing and

insurance programs,

(2) Modification of loss potential including coastal

zoning, building codes, acquisition, and relocation,

and

(3) Modification of erosion hazard through groins,

bulkheads, revetments, seawalls, beach nourishment,

and breakwaters (White, 1976).

Number one above is clearly a poor choice for most people

who have large sums invested in shore property. Number two

includes those adjustments generally considered as non-

structural while three utilizes the structural alternative.

The major issues in dealing with the above include:

(1) How to provide least expensive, most effective and

most acceptable protection,

(2) How to avoid conflicts with property owners.

(3) How to finance structural alternative if cost has

to be borne by government.

(4) How to resolve the public access and ownership

question.

(5) How to resolve disagreements about environmental

impact (Mitchell, 1975).

-114-

Adoption of a specific response to erosion can increase,

decrease, or have no effect on the likelihood of other

adjustments being adopted. For example, if erosion control

and protection structures are adopted, it is likely that

they will be complimented by warning systems and relief and

rehabilitation programs. It is less likely that non-

structural controls and land use management tools will be

employed (NOAA, 1976). A mix of alternatives promises to

be the most effective program. An example might be an

ordinance for hazard occupance coupled with beach nourishment

or other structural alternative.

Land regulation of coastal hazards:., and sensitive areas

can provide a long term mechanism for effective mitigation

of erosion losses. Such regulations should be put into

effect immediately to prevent additional losses and a

continuance of poor land management. Regulations enacted

now will do little to prevent short-term losses to existing

development in hazard areas.

The currently available-information shows that control

of development along the coast, in many instances, may be

the best practical way of reducing shoreline damage

(Environment Canada, 1973).

Regulation should not arbitrarily impose obstacles to

proper occupancy. It should require sound occupancy

-115-

standards and should allocate shoreline areas to uses that

will be in harmony with both the environmental and antici-

pated human needs.

-116-

LAND USE CONTROLS

There are generally three responses to erosion hazard.

They are:

- Modification of the loss potential

- Modification of the erosion hazard

- Acceptance of unavoidable loss

The following are examples of management alternatives

that generally modify the potential for loss:

- Density credits

- Compensable set-backs

- Set-backs

- Planned unit development

- Acquisition

- Permits

- Moritoria on building construction

- Building codes

- Scenic easements

- Transfer of development rights

- Erosion and sediment control laws

- Subdivision review process

- Zoning

The following are examples of strategies that generally

modify the erosion hazard:

Beach sand protection.laws

-117-

- Grading and slope ordinances

- Drainage and sanitation codes

- Standards for seawalls, revetments, bulkheads and

groins

- Regulations on tree cutting

Regulations on filling, dredging and grading

The following are those alternatives that can generally

be considered for bearing the unavoidable loss by erosion:

- Flood insurance

- Relocation

It should be pointed out that not all of the above will

likely be adopted by any municipal ordinance or group of

ordinances. It is anticipated that a mix of the above will

be utilized to achieve the desired results for the munici-

pality. In fact, some of the above may already exist in

municipal ordinances. The above strategies are offered as

a means of dealing with particular problems related to-

specific sites.

REQUIRED INFORMATION

It should be apparent t-hat to successfully construct,

administer, or enforce an erosion control ordinance, a

considerable amount of information must be in hand. To

preserve the qualities of the coastal zone through proper

planning, government must undertake a careful examination

of construction practices, structural protection techniques,

and engineering, as well as a comprehensive examination of

conservation needs and the natural processes affecting the

shore. Understanding nearshore processes is essential to

planning and the development of shorelines (Inman, 1978).

Finalizing any ordinance seeking to prevent haphazard

development of the shore zone requires-the expertise of

engineers and geomorphologists specializing in coastal

phenomena.

In addition to a comprehensive data base, the plan should

include both the natural and socio-economic resources and

general condition of the shore area. In planning for the

shore structure section ofthe ordinance, it is important to

examine the legal and social consequences where such protec-

tion results in significant impact on the physical and

ecological aspects of the environment.

As expressed in the Coastal Erosion Element of the Great

Lakes Basin Commission's comprehensive coordinated joint plan,

several questions he ed to be asked in the construction of

a plan. Specifically:

(1) Has the area in which the property is situated

been mapped for its susceptibility to erosion?

The Erie County, Pennsylvania shoreline of Lake Erie was mapped

early in the Coastal Zone Management effort. Various reaches were

classified as low, moderate, or critical hazard dependent on the

evidence of slight, moderate, or severe erosion taking place at the

time of the observation. These estimates were necessarily subjective.

Information generated by a planned geotechnicaZ examination of the

bluffs and beach areas will be available for incorporation into the

planning effort.

(2) How fast is the erosion occurring?

Bluff recession rate (:kzta is presently available as a result of

work done in L974 (Knuth, Crowe., Z975). This data will be upgraded

during L981 as a result of a monitoring program planned as a part of

a geotechnical examination of the shore zone. Erosion of the shore

itsetf is difficult to determine. Examination of aerial photographs

and old navigation charts promises to reveal more information about

shore erosion (Carter, Z976). Changes in lake level can "create" or

diminish the amount of beach area at a given point through time.

(3) Are there any shore protection structures nearby

that might interrupt nearshore currents that carry sediment?

-120-

A shore structure inventory (Knuth, Z978) was conducted by the

U.S. Army Corps of Engineers in Z978 for the Pennsytvania portion of

Lake Erie. The occurrence of existing structures and the impact they

have on erosion and recession ss an &tem for further study. Some

cause and effect statements can be made relative to breakwater design

at Presque IsZe State Park and a jetty at a Pennsylvania Fish

Commission access point at Walnut Creek. The impact that additional

structures may have on erosion must be considered during any planning

efforts in the future.

(4) How far are existing structures from the edge of

the bank or bluff?

Existing structures are located variously from the very edge of

the bluff to some landward distance away. Several structures are in

imminent danger of failure due to persistent recession. The Bluff

Recession and Setback Act provides that all municipalities shall deter-

mine a safe setback distance from the bluff crest and provide an

ordinance that can control construction in the future.

(5) Can existing structures be relocated if necessary?

If relocated, how much will it cost?

The relocation of most structures on the shoreline would generally

provide an expense out of proportion with the value of the structure. In

many cases property boundaries are not sufficiently deep to accommodate

relocation on the same site. Many structures would provide insurmountable

difficuZties due to design even given enough property and a more modest

-121-

reLocation expense.

(6) Is property adequately drained?

Current investigation into storm water management in Erie County

wiZZ hopefuZZy shed more tight on this important eZement. There

exists a definite cause and effect reZationship between overZand and

interior drainage and recession rates of the btuffs saturated with

ground water or eroded by runoff from beyond the bZz,(ff crest. ControZZing

drainage is a necessary first step in preventing or stowing recession

in the future.

(7) If it is necessary, is structural protection

affordable?

As mentioned etsewhere in this report, attempts at Zow-cost shore

protection can frequentZy be detrimentaZ beyond any positive effects

the structure may have. The best protection is quite expensive sur-

passing $500 per foot of shore protected. Few, if any, individuaZa can

provide this measure of protection and it is doubtfuZ if the amount

couZd be justified given current market vaZues.

The Above questions are p timarily posed to provide a

planner with guidelines with which to judge requests for

building permits for shore protection structures. if

proper answers are to be given the property owner the above

serv*mp&s to indicate the need for additional information. To

be of maximum utility the plan should answer these questions

-122-

as a primary first step in the local permit process.

Essentially, each of the following needs to be addressed

in the planning sequence! (White, 1978):

(1) Areas potentially affected by extreme natural

events must be delineated. Such hazard areas can be divided

into:

(a) bluff recession hazard

(b) shoreline erosion hazard

(d) stream mouth flooding

(2) Estimates of vulnerability must recognize that

human occupation-of a vulnerable area always involves the

beneficial use of a resource and the risk of possible loss.

(3) More than one adjustment should be offered to

mitigate each of the above hazard factors. For example, the

following range of adjustments are available to the munici-

pality for inclusion in an ordinance or a set of regulations:

(a) Subdivision regulations

(b) zoning

(d) Building ordinances

(e) Easements;

On an advisory basis the following could be offered:

-123-

(a) New or improved warning systems including pre-

paredness plans. Effective hazards disclosure statements

should be made part of any one or combination of the

following:

- Environmental impact reports

- Hazard warning in deeds

- Hazard warning in mortgage agreements

- Covenants

- Law stipulating a hazard disclosure at time of

sale

(b) Control and Protection works information and

advisory bulletins

Insurance Programs.

In some hazardous areas, site specific investigation

may be required in order to determine whether development

anywhere on a given parcel would be safe. The developer

could be prepared to provide local authority with a profes-

sionally prepared, site specific report which indicates

that the proposed development would be safe.

An alternative to establishing an erosion plan and

ordinance would be a continuation of existing coastal hazards

(status quo). For example, with no increase in research and

data collection, some permit applications and development

-124-

proposals will continue to receive inadequate analysis and

evaluation (GLBC, 1980).

An ordinance should ensure wise coastal development

and also place the burden of the cost of protection on the

property owner who knowingly chooses to live in a hazardous

area.

-125-

STATUTORY AUTHORITY

State and local governments should exercise regulatory

authority to control development in coastal hazard areas in

an effort to prevent future flood and erosion damages (GLBC,

Great Lakes Basin Plan, 1980).

states have the authority to grant powers to cities,

towns and townships to regulate the use of land within

their boundaries. In addition to building codes and zoning

ordinances, the municipality may enact regulations on exca-

vations, dumping or construction of shore structures. if

the municipality has enacted a specific ordinance, shore

protection works above ordinary high water fall within

municipal-authority. The local government then has the

responsibility to see things broadly and to plan for the

long term welfare of its; citizens on the local level.

In Pennsylvania local governments retain the power to

regulate land use and perform comprehensive planning. The

Municipalities Planning Code grants local governments a

great deal of discretion in exercising these powers. It is

legally possible to institute new and different land con-

trols as long as they do not violate constitutional princi-

ples. The following are some possibilities:

- Storm water management controls

- Zoning to conserve valuable natural resources

-126-

Development controls for hazard areas

The subdivision and land development regulation may

include provisions to ensure that "land that is subject to

flooding, subsidence... shall be made safe for the purpose

for which such land is proposed to be used, or that such

land shall be set aside for uses which shall not endanger

life or property or further aggravate or increase the

existing menace." (Pennsylvania Municipalities Planning Code)

Zoning ordinances may include additional classification

within districts "for regulation, restriction, or prohibition

of uses and structures at or near ... natural or artificial

bodies of water, places of relatively steep grade or slope...

floodplain areas and other areas having a special character

or use affecting and affected by their surroundings."

(Pennsylvania Municipalities Planning Code)

-127-

DAM SAFETY AND ENCROACHMENTS ACT

While not delegating specific authority to local

municipalities, the Dam Safety and Encroachments Act never-

theless provides oversight to any planning elements conceived

at the local level. The purposes of the Act are to:

- Provide for the regulation of dams, reservoirs, water

obstructions, and encroachments in the Commonwealth,

in order to protect the health, safety, and welfare

of the people and property.

- Assure proper planning, design, construction, main-

tenance, monitoring, and supervision of dams and-

reservoirs, including such preventative measures as

are necessary to provide an adequate margin of safety.

- Protect the natural resources, environmental rights

and values secured by the Pennsylvania Constitution

and conserve the water quality, natural regime, and

carrying capacity of watercourses.

- Assure proper planning, design, construction, main-

tenance, and monitoring of water obstructions and

encroachments, in order to prevent unreasonable

interference with. water flow and to protect navigation.

-128-

THE BLUFF RECESSION AND SETBACK ACT

The Bluff Recession and Setback Act gives local

authority a specific mandate to provide setback ordinances

for the construction of structures on the bluff crest.

This ordinance shall be properly incorporated into any

shoreline erosion ordinance. The purposes of the Act are to:

- Encourage planning and development in bluff areas

which is consistent with sound land use practices.

- Protect people and property in bluff areas from the

dangers and damage associated with the inevitable

recession of bluffs.

- Prevent and eliminate urban and rural blight which

results from the dama ges of bluff erosion and

recession.

- Minimize the expenditures of public and private funds

for shoreline protection and bluff stabilization

structures and activities.

- Authorize a comprehensive and coordinated program

to regulate development activities through the use

of setback ordinances in bluff recession hazard areas,

designed to prevent continuing destruction of private

property and structures.

-129-

Encourage local administration and management of

bluffs consistent with the Commonwealth's duty as

trustee of natural resources, and the people's

constitutional right to the preservation of the

natural, scenic, aesthetic and historic values of

the environment.

_130-

THE TAKING ISSUE

The taking issue is relevant only in a small portion

of land use control decisions. In fact)land use controls

should withstand a taking challenge where:

The owner of the land is left with a reasonable,

profitable use, even though it is substantially less

than the most profitable use.

-The restriction can be shown to be necessary to

protect the public health, safety or welfare

(environmental hazards such as floods, landslides,

sinks, limited water supplies, susceptibility to

erosion and runoff damage, and temporary restrictions

to protect mineral resources are the easiest to

document).

The local government has not attempted to use zoning

controls where it: should actually purchase land for

a given activity such as public recreation.

-131-

NEED FOR PLAN

There is an obvious need for a comprehensive planning

effort for the placement: of erosion control structures and

development of lands ad-acent to or within a hazard area.
J

As erosion continues as a threat to individual property

owners the response is generally to prevent losses of

property by the construction of various shoreline protection

devices. The crucial issue is the extent to which a landowner

may take protective measures without incurring a liability

for injury to his neighbor. (Hildreth, 1980)

In an attempt to control haphazard development in hazard

areas developmental controls are obviously needed. Weak

controls will create indecision in response while too strict

-controls could'be challenged as a governmental "taking" of

private property without. just compensation. A challenge

would probably succeed if scientific accuracy is lacking in

the information relied upon in determining developmental

controls. Two aspects of Common Law apply.

(1) The Common Enemy Doctrine

The Common Enemy Doctrine states that a landowner may

do anything to repulse surface waters from his land without

liability for damages to others caused by his actions. A

neighboring property owner has the.right to protect his

property as well. Any injury to neighboring land is said

-132-

to be damnum absque injuria. A property owner may apply

this law only in the face of imminent harm.

(2) Civil Law

Civil Law states that an upstream owner may not impede

the downstream flow; applicable in the case of shore struc-

tures when littoral drift is considered as flow. A property

owner could collect damages as a result of such interference

by his updrift neighbor and could enjoin unreasonable

behavior.

The rights of property owners are determined by

assessing all of the pertinent data including-

- Surrounding circumstances of the particular issue,

- Nature of the improvement,

- Extent of interference with surface water,

- Value of improvement compared to injury to a neighbor,

and

Foreseeability of: the harm. (Hildreth, 1980)

To be successful a regulatory plan must recognize the

rights of all citizens. In addition it must respect the

natural processes active in bluff recession and beach

erosion. The complicated nature of the interaction of

natural processes and human occupance is the essential

element in any ordinance written for hazard zone occupance.

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OBJECTIVES OF THE ORDINANCE

To be successful a shore erosion ordinance must act to

guide both public and private decisions related to shore

zone occupance and, as a result, realize the goals and

objectives of the plan.

The plan should have a positive rather than a negative

or restrictive tone. The emphasis should be placed on guid-

ing development in areas where such development will not

create a negative impact on the environment or be affected

by environmental changes.

The following can be considered as objectives and are
gleaned from various'sources (McKinney, 1980, The Conser-

vation Foundation, 1980, Michigan Department of Natural

Resources, 1973).

(1) New Development in the shorelands should be limited

to those activities and facilities specifically requiring

a shoreland location.

(2) Permissible development should be planned,

designed, constructed, and operated and maintained as to

harmonize with the capacities and tolerance limits of the

natural shoreland ecosystem.

(3) Public policy should foster and facilitate to

the maximum extent possible the acquisition of key shoreland

environmental areas into the public ownership and their

management for present objectives.

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(4) Restrict construction of new buildings in the

shore zone to remove developmental pressures.

(5) Provide information about protective structures

for eroding shorelands.

(6) Manage coastalwatersheds for least alterations

of natural patterns of stormwater runoff.

(7) Preserve ecologically vital areas such eks edge

zones and beach areas.

(8) Preserve the integrity of coastal geologically

protective structures--beaches, erodible banks and bluffs.

(9) Protect the configuration of coastal water basins

against adverse alterations (dredging or cutting).

(10) Protect coastal waters from pollution.

(11) Protect public health and welfare with regard to

dangers associated with coastal hazard areas.

(12) Provide a long-term, cost effective strategy for

the reduction of infrastructure losses to developed

coastal areas.

(13) Protect and enhance'the natural coastal resource

systems of the beach bluff interface so as to obtain maximum

level of natural storm protection; the environment of

recreational beaches and environmental quality as related

to these ecosystems should also be realized.

(14) Provide increased opportunity for the general

public to have unrestricted beach access.

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(15) Minimize expenditures of public monies for costly

erosion protection structures.

(16) Protect the land water interface by controlling

shoreline alterations.

(17) Control building sites, placement of structures

and land uses through:

(a) s eparating incompatible land uses

(b) prohibiting certain uses detrimental to the

shoreland area.

(18) Preserve shore cover and natural beauty through:

(a) restricting the removal of natural shoreland

cover

(b) regulating shoreline encroachments by struc-

tures

(19) Provide an information service to prospective

owners warning of the erosion hazard that may exist at the

particular site.

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SAMPLE EROSION HAZARD ORDINANCE

The following erosion hazard ordinance is an adaptation

after D. A. Yanggen's work for the.Wisconsin Coastal Zone

Management Program. As, a working model, it incorporates

many of the elements that would have prime consideration

for the Pennsylvania portion of the Lake Erie Shore. It is

well known that there are great similarities among all

coastal Great Lakes States.

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SAMPLE EROSION HAZARD ZONING PROVISIONS

The following coastal erosion hazard provisions are

designed for inclusion in a municipal comprehensive zoning

ordinance. These sample coastal erosion hazard provisions

are more detailed and elaborate than those a local govern-

ment would likely include in its own zoning ordinance.

Setting forth a full array of provisions gives a better

picture of possible items for inclusion in a particular

ordinance. More detailed provisions and accompanying

commentary give insight: into some of the factors that should

be considered in administering a simpler ordinance. Some of

the provisions could be adopted as an erosion hazard policy
p.la'n which would be incorporated into the regulations by

reference. The choice of the most appropriate provisions

will depend on the local land use policies, the type of

hazard, and the data available.

1.1 Finding of Fact

The coastal erosion hazard areas of are subject

to substantial erosion. These hazard areas have been iden-

tified on the basis of studies of shoreline recession,

stable slope angles, and other engineering and geological

studies and principles. Improper land use within these

areas causes erosion damages in the form of property losses,

environmental degradation, and the impairment of public

rights in navigable waters. These erosion damages are the

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result of: (1) structures placed in areas which will be

undermined by erosion; (2) land use activities that accel-

erate erosion; and (3) improperly designed, installed, and

maintained protective measures which accelerate erosion on

nearby properties and cause environmental damage.

1.2 Statement of Purpose

It is the purpose of these regulations to protect the

public health, safety, and general welfare and to reduce

erosion damages by: (1) establishing a setback line designed

to minimize losses over a year period; (2) restricting

uses which are vulnerable to erosion damage; (3) regulating

land disturbance, stormwater drainage and other activities

which increase erosion; and (4) requiring that proposed

protective works are properly designed, installed and

maintained

2.0 Lands to Which Regulations Apply

(Option #1) These regulations shall apply to all lands

which are within feet of the ordinary high water mark

of Lake Erie.

(Option #2) These regulations shall apply to all lands

within the erosion hazard areas as shown on the final coastal

zone boundary map. Where specific distances from the

ordinary high water mark are described on the map, these

distances shall control.

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3.0 General Provisions

3.1 Effect on Other Provisions

3.11 These provisions are intended to supplement

and not to repeal other applicable regulations;

however, where these provisions impose greater

restrictions they shall control.

3.12 No lot shall hereafter be created, subdi-

vided or otherwise established without sufficient

depth to accomodate structures in compliance with

these provisions.

3.2 Warning and I)isclaimer of Liability

These provisions are considered to be the minimum

reasonable requirements necessary for reducing erosion

damage for a year period. These requirements are

based upon engineering, geological, and other scientific

studies and principles. Faster rates of erosion may occur.

Erosion rates may be increased by natural causes such as

major storms or high lake levels or by manmade causes such

as the construction of erosion control structures or land

disturbing activities. These regulations do not guarantee

or warrant that development in compliance with its terms

will be free from all erosion damage. Reliance on these

regulations shall not create liability on the part of the

enacting government or any officer or any employee thereof.

4.0 Erosion Hazard Setback Lines

Within the boundaries of the erosion hazard areas

established by Section 2.0 the minimum erosion setback shall

be as follows:

4.1 Bluffs

4.11 A stable slope angle setback shall be

established at a ratio of 2 1/2 feet horizontal

distance to every one foot vertical distance.

The measurement shall be made from the ordinary

high water mark perpendicular to the shoreline.

There shall be two such measurements made for

every 100 feet of shoreline at points not less

than 50 feet apart. The stable slope angle set-

back shall be! a line connecting these two poin-ts

or such line extended. In cases of an irregular

shoreline or where the lots are not perpendicular

to the shoreline, the Zoning Adm inistrator may

require that additional points of measurement be

used to determine the stable-slope angle setback.

4.12 An additional recession rate setback shall

be measured from the stable slope angle setback.

The year recession rate shall be calculated

using the average annual recession rate indicated

on the official map. Where no recession rate is

known, the safety factor shall be calculated by

assuming a foot per year average annual

recession rate.

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4.13 A "bluff" is that segment of the shoreline

which is 10 feet or more in height and which has

a rise of 10 feet or more vertical distance in

less than 25 feet horizontal distance.

4.2 Ravines

A stable slope angle setback shall be measured at

a rate of 2 1/2 feet horizontal distance to every one

foot vertical distance for all ravines 10 feet or

deeper. The measurement shall be made from the center

of the deepest part of the ravine.

4.3 Dunes and Beaches

4.31 A recession rate setback shall be measured

from the ordinary high water mark. The

year recession rate shall be calculated using the

average annual recession rate indicated on the

official map. Where no recession rate is known,

the safety factor shall be calculated by assuming

a foot -per year average annual recession

rate.

4.32 "Dunes and Beaches" are those erodible

segments of the shoreline which are not in bluffs.

4.4 There shall be a minimum setback of 75 feet from

the ordinary high water mark in all cases. ordinary

high water mark means the point on the bank or shore

to which the presence or action of surface water is

so continuous as to leave a distinct mark such as by

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erosion, destruction or prevention of terrestrial

vegetation, predominance of aquatic vegetation, or

other easily recognized characteristic. Where the

bank or shore at any particular place is of such

character that it is difficult or impossible to

ascertain where the point of ordinary high water is,

recourse may be had to the opposite bank of a stream

or to other places on the shore of the lake to

determine whether a given stage of water is above or

below the ordinary high water mark.

4.5 The ordinary high water mark and setback lines

shall be determined by the Zoning Administrator on the

basis of data submitted by a licensed surveyor or on

the basis of a field inspection. Where conflicts arise

the Zoning Officer shall contact the Department of

Environmental Resources to make an official determina-

tion of the ordinary high water mark.

4.6 The Zoning Agency may issue a conditional use

permit as provided in Section 6.0 allowing modification

of the erosion hazard setback upon presentation by the

applicant of acceptable engineering studies documenting

(1) lower recession rates, (2) more stable slope condi-

tions, (3) plans for structural protection against

wave attack, (4) plans for stabilization of the bluff

or shoreline.

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5.0 Regulation of Uses Within Erosion Hazard Setbacks

These provisions supplement the underlying zoning

which remains in effect to the extent its provisions are

more restrictive. The following uses are prohibitive uses,

permitted uses and conditional uses within the erosion

hazard setbacks established by Section 4.0.

5.1 Prohibited Uses

5.11 Residential, institutional, commerical,

industrial, agricultural and public buildings

designed for permanent use at the proposed

location.

5.12 Septic tank systems and other on-site-waste

disposal facilities.

5.2 Permitted Uses

5.21 Open space uses

5.22 Storage of portable equipment, machinery or

materials

5.23 Accessory buildings which can be easily and

economically moved, such as storage sheds

5.24 Minor structures such as driveways, walkways,

patios, and fences

5.3 Conditional 'Uses

5.31 Buildings and structures which are readily

removable in their entirety provided they are so

located and constructed that they may be removed

prior to erosion damage

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5.32 Other uses similar to those permitted in

5.2 and 5.3 which are determined by the Zoning

Administrator to be compatible with the intent

and purpose of these regulations. (See also 6.0

Regulation of Shoreline Protection Devices and

Land Disturbances.)

6.0 Regulation of Shoreline Protection Devices and Land

Disturbances

6.1 The following shoreline protection activities are

conditional uses:

6.11 All structures or deposits, which are

shoreline protection devices, below the ordinary

high water mark.

6.12 The placement of shoreland protection

devices above the ordinary high water mark

6.13 "Shoreline protection devices" means break-

waters, groins, revetments, seawalls, bulkheads,

rip rap, deposition of materials such as stone

and concrete rubble, bluff stabilization projects

and similar measures.

6.2 The following land disturbing activities are

conditional uses when conducted within feet of

the ordinary high water mark or the erosion hazard

setback, whichever is the greater distance.

6.21 Alteration of more than square feet

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of wetlands. For purpose of this regulation

"wetlands" are defined as those areas where

water is at, near or above the land surface long

enough to be capable of supporting aquatic plants,

and which have soils indicative of wet conditions.

6.22 Filling or grading on all slopes of 20%

or more

6.23 Filling or grading of more than square

feet on slopes of 12-20%

6.24 Filling or grading of more than square

feet on slopes of 12% or less

6.25 Dredging, construction or other work on any

artificial waterway, canal, ditch, lagoon or

similar waterway

6.26 Removal of more than square feet of

vegetation. Where vegetation is removed-it shall

be replaced, as far as practical, with other

vegetation that is effective in retarding runoff,

preventing erosion and preserving natural beauty.

7.0 Conditional Uses

7.1 General

Conditional uses are uses which may create special

problems and hazards if allowed as a matter of right.

Whether such uses can be appropriately established

depends on the facts and circumstances of the particular

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situation. The conditions which may be attached to

development permission can, in some instances, avoid

adverse effects on adjoining property or the public

welfare.

Conditional uses are allowable only upon written

approval by the Zoning Agency authorized to issue

conditional use permits. The Zoning Agency may, after

public notice and hearing, permit, deny, or permit the

use subject to attached conditions. In passing upon

a conditional use the zoning agency shall specify the

information to be supplied, evaluate the proposed use

according to specified standards, and attach appro-

priate conditions to development permission.

7.2 Procedure

7.21 Any use listed as a conditional use shall be

permitted only upon application to the Zoning

Administrator and issuance of a Conditional Use

Permit by the Zoning Agency.

7.22 Before passing upon an application for a

Conditional Use Permit the Zoning Agency shall

give notice and hold a public hearing.

7.23 The Zoning Agency shall, when appropriate,

seek technical review assistance from the Depart-

ment of Environmental Resources or the U.S. Army

Corps of Engineers, and other agencies having

relevant expertise.

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7.3 Information -to be Supplied

The Zoning Agency may require the applicant to

furnish the.following data which it finds pertinent

and necessary for its determination:

7.31 A plat of survey prepared by registered land

surveyor, or other maps drawn to scale showing

the location and dimensions of: property bound-

aries, the ordinary high water mark, contours of

the site, required and proposed yards and setbacks,

existing and proposed vegetative cover and land-

existing and proposed buildings, struc-

tures, driveways, parking and loading areas and
streets, existing and proposed areas for *the

storage of equipment, machinery and materials,

areas of proposed grading, filling, dredging and

vegetative removal, and existing and proposed

methods of controlling stormwater runoff and

problem groundwater conditions.

7.32 Plans of buildings or other structures,

sewage disposal facilities, water supply

facilities.

7.33 A description of the method of operation

of industrial and commercial uses.

7.34 A report, prepared by a registered profes-

sional engineer, certifying that the site is or

can be made suitable for the proposed development.

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The report shall consider, describe, and analyze

the following:

(1) past, current, and future wave induced

erosion based upon recession rates and

wave energy calculations;

(2) geologic conditions including the soils

and stratigraphy of the site and an

analysis of the properties and stability

of the materials present;

(3) ground and surface water conditions and

variations including changes that will.,

be caused by the proposed development;

(A) plans and specifications for bluff and

shoreline stabilization measures and

plans and specifications for measures

to protect against wave erosion, includ-

ing the estimated life of such structures,

thiBir.cost, the maintenance required,

and the effect on nearby properties and

the shoreline of the lake environment;

(5) where a modification of the erosion

hazard setback is proposed the minimum

setback required to provide a reasonable

degree of safety to the proposed use for

a period of years;

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(6) methods to be used to control surface

erosion and storm watdr runoff during

and after construction;

(7) the elevation of the 100 year flood and

storm surges where the site is subject

to flooding

7.35 Other pertinent data necessary to determine

if the proposed use and location is consistent

with the requirements of these regulations.

7.4 Standards Applicable to all Conditional Uses

In passing upon a conditional use, the Zoning

Agency shall evaluate the proposed use in terms of:

7.41 The erosion and flooding hazard

7.42 The need of the proposed*use for a shore-

line location

7.43 Compatibility with nearby land uses

7.44 Adequacy of proposed waste disposal and

water supply systems

7.45 Location with respect to existing or

proposed roads

7.46 The demand for public services engendered

and the adequacy of existing services to meet the

demand

7.47 Protection of the scenic beauty of the

shoreline

7.48 Protection of public rights in navigable

waters I

7.5 Conditions Which May be Attached to Conditional
Uses 7.51 Upon consideration of the factors listed

above, the Zoning Agency may attach such condi-

tions, in addition to those required elsewhere in

this ordinance, that it deems necessary to

further the purpose and intent of these regula-

tions. Such conditions may include, without

limitation because of specific enumeration:

bluff and shoreline stabilization measures;

measures to protect against wave'attack;.control

of groundwater seepage; revegetation and land-

scaping; control of surface water runoff; the

continued and regular maintenance of the above

listed measures; design and construction of

structures to be moveable in accordance with

accepted architectural or engineering standards;

the removal and relocation of uses prior to

erosion damages; type of construction; construc-

tion commencement and completion dates; perfor-

mance standards and operational controls;

dedication of land; sureties, and performance

bonds; deed restrictions; and other measures

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designed to ensure the satisfactory location and

maintenance of uses in accord with the purpose

and intent of these regulations.

7.52 When a conditional use is approved a record

shall be made of the land use and structures

permitted, and the conditions attached to such

permission. Violations of conditions attached to

a conditional use shall constitute a violation of

this ordinance. The Zoning Agency may, after

notice and hearing and opportunity for corrective

action, revoke the permit and seek a forfeiture

or injunctional order as provided by law.

7.53 All legal existing uses which would be

classified as conditional uses if they were to

be established after the effective date of this

ordinance or its amendment are hereby declared to

be conforming conditional uses to the extent of

the existing operation only. Any addition,

alteration, extension, or any other change in

the conditional use procedures as if such use were

being established anew.

8.0 Non-conforming Uses

The lawful use of a building or premise existing at the

effective date of this ordinance or its amendment may con-

tinue in the same manner and to the same extent subject to

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the following requirements:

8.1 Routine repairs and maintenance,are permitted.

8.2 No alterations, additions, or expansions shall

occur which increase the dimensional nonconformity

within the erosion hazard setback unless a variance

is obtained as provided in Section 9.0.

8.3 The use of any vacant lot or parcel shown on a

recorded subdivision plat, assessor's plat or a

conveyance, recorded in the office of the Register of

Deeds, which does not conform to the erosion hazard

setback shall be permitted only upon the issuance of

a variance by the appropriate Board.

8.4 The other provisions of the ordinance relating

to nonconforming uses-and the provisions of

are complied with.

9.0 Variances

A variance from-the erosion hazard setback may be

granted by the Board of based upon the following

standards:

9.1 No variance shall be gran ted which would have the

effect of allowing in any district a use not permitted

in that district.

9.2 No variance shall be granted which would have the

effect of allowing a use of land or property which

would violate state laws or administrative rules.

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9.@ A variance may be granted where strict enforce-

ment of the terms of this ordinance results in

unnecessary hardship and where a variance will not be

contrary to the public interest, and will allow the

spirit of the ordinance to be observed, and substantial

justice done.

9.4 Conditions shall be attached in writing to all

approved variances where such conditions will achieve

compliance with the standards of this ordinance. Such

conditions may include:

9.41 The proposed use is located as far landward

of the erosion hazard setback as is practical.

9.42 Septic tank systems and other on-site waste

disposal facilities are placed landward of the

principal structure

9.43 The proposed structure is designed, con-

structed, and located so as to be moveable to a

safe location prior to erosion damage and a deed

restriction is recorded requiring removal.

9.44 Those conditions which may be attached to

conditional uses as specified by 7.5.

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SUMMARY CRITERIA: MODEL ORDINANCE

The comprehensive plan and companion ordinance for

erosion control will contain the following:

� Public expenditures for coastal hazard management

efforts will be reduced; i.e. with a decrease in the

amount of hazard prone development, there will be a

concomitant decrease in government effort to aid in

flood or erosion prevention or mitigation.

� The quality of the coastal environment should be

enhanced. Properly planned and sited development would

in many cases, obviate the need for structural protec-

tion. Relatively more shoreline would remain in an

unprotected, natural condition.

0 Shoreline occupancies that will permanently degrade

sensitive land-water environmental interfaces should

not be permitted. Changes considered may be due to

land development practices or the nature of the

subsequent human use.

0 Land development and construction operations should

not permanently degrade sensitive land-water environ-

mental interfaces. Temporary degradation of conditions

affecting only the renewable oreasily replaceable life

forms should be permitted.

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0 Proper federal and other permits for construction must

be obtained. Penalties should be established for

violation of this criterion and violators should be

legally and enforceably responsible for restoration

of pre-violation natural conditions.

-157-

PERMITS

At the real risk of adding another layer to the

already weighty permit structure, the municipality should

consider a permit system for the construction of structures

designed to ameliorate erosion hazard. To assure that all

parties in the shoreline areas are considered, there needs

to be a comprehensive plan whereby a municipality can

regulate development in the best interests of all concerned..

Such structures are regulated by the Corps of Engineers

to assure that structures in, or adjacent to, waterways do

not impede navigation. Permits required by the state

generally provide for control of structures resting on, or

affecting, Commonwealth. waters. A local permit could and

should regulate structures to ensure that the sensitive

shore areas are not impacted adversely by the addition of

erosion control structures.

The decision by the property owner to provide a

structural alternative to the erosion hazard has selected

from one of the following four choices:

- Pay the high cost of proven, engineered structures

- Devise a low-cost alternative that offers temporary

protection at best,

- Sell the property thereby transferring the problem,

-jr-8-

Do nothing.

Since the alternative most frequently chosen is a

low-cost structure, the municipality has the responsibility

to regulate the construction to assure the health, safety

and general welfare of all.

Most of the protective works on the Great Lakes have

been constructed by private shore owners. Many of these

structures have not been properly designed and do not

adequately protect the shorelines and, in some cases, can

aggravate erosion in their vicinity. (Environment Canada,

1973)

It should be accepted that erosion can and should only

be controlled in isolated locations, prudently selected.

It should also be accepted that such control shifts the

damage from one area to another.

In establishing standards for protective structures,

the community should ensure that they are compatible with

federal and.state criteria. In addition, such standards

should provide additional restrictions to fulfill the

responsibility as a local government but should be clearly

expressed. If the process for reviewing applications for

permits cannot be made more expedient and predictable,

some of the basic environmental protections are threatened

-159-

by lack of adherence to ambiguous 'and superfluous regula-

tions. (DeHart, 1979)

It should be noted that there is a certain risk implied

in granting a permit. For example, a California Superior

Court decision has held that a county is responsible for

private property damage resulting from development in a

hazardous area for which the county had issued a permit.

(NOAA, 1976)

The decision to issue a permit is based on an evalua-

tion of the possible impact of the proposed action or

activity on the public interest as a result of interest

not only in protection of property but in protecting

resources as well.

The benefit which may reasonably be expected to occur

from the proposal must be balanced against its reasonably

forseeable detriment. All factors which may be relevant

to the proposal should be considered; they are:

- Conservation

- Economics

- Aesthetics

- General Environmental Values

- History Values

- Fish and Wildlife Values

- Land Use Classification

-160-

- Navigation

- Recreation

- Food Production

- Water Supply

- Water Quality

- Energy Needs

- Safety

- Needs and Welfare of the Public

Additional to the cost of capital construction then

are the indirect and intangible costs of social, environ-

mental and aesthetic disruption. Some present structures,

if designed properly, cost more than the land is worth.

Very little cost-benefit analysis is taking place. Erosion

damages conti.nue to increase and strategies depending

solely on structural alternatives have had little success.

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THE ISSUANCE OF GENERAL PERMITS

A model erosion control plan or ordinance ought to

spell out the kinds of activities taken as a group that

might fall under the concept of the general permit. Some

regulatory programs have issued broad general permits

covering new construction of certain structures within

their jurisdiction while others have looked to in-de pth,

site specific studies to determine permitting problems.

The overall objectives of a general permit can:

- Result in issuance of a general permit,

- Be economical when compared to future savings in

manpower!

- Protect from adverse impacts if generally permitted

construction is taking place, and

- Be accepted and generally understood by the general

public.

And the advantages include:

- Provides definite and positive approach to assisting

regulatory agencies,

- Reduces processing time,

- Ensures orderly development,

- Improves respect and awareness, and

- Protects the aesthetics of the coastal zone.

It should be clear, however, that a general permit is

-162-

issued only if and when the proposed action meets all the

criteria for that particular type of action. Deviation
from the generally permitted design will be cause for site

specific examination.

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APPENDIXI
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BIBLIOGRAPHY
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BIBLIOGRAPHY

Alberstadt, Joseph, 1973, Untitled, Letter to the Editor,
Erie Morning News, Erie, Pennsylvania, April 4

Allen, J. R. and K. F. Nordstrom, 1977, "Beach Form Changes
in the Lee of Groins at Sandy Hook, New Jersey", Coastal
Sediments 177, ASCE Specialty Conference, Charleston,
S.C.

Armstrong, J. M., 1976, "Low Cost Shore Protection on the
Great Lakes", Coastal Engineering 176, ASCE Specialty
Conference, Honolulu, Hawaii

Armstrong, J. M. and C. L. Kureth, 1979, "Some observations.
on the Longard Tube as a Coastal Erosion Protection
Structure," Coastal Structures 179, ASCE Specialty
Conference, Alexandria, Virginia

Armstrong, J. M. and R., B. DenUyl, 1977, "An Investment
Decision Model for Shoreland Protection and Management,"
Coastal Zone Manageient Journal, 3:3

Arno, N, (undated), "Help Yourself: A Discussion of the
Critical Erosion Problems on the Great Lakes and
Alternative Methods of Shore Protection," U.S. Army
Corps of Engineers, North Central Division, Chicago, Ill.

Basillie, J. H. and Dennis Berg, 1977, "State of Groin
Design and Effectiveness," Proceedings 13th Conference
on Coastal Engineering, ASCE Specialty Conference, New
York, New York

Berg, Dennis and George Watts, 1971, "Groins and Groin
Systems: A review of Research," Shore and Beach,
October, 1971

Berkemeier, W. A., 1979, "Effects of Structures and Lake
Levels on Bluff and Shore Erosion in Berrien County
Michigan, 1970 to 1974," U.S. Army Corps of Engineers,
Coastal Engineering Research Center, Ft. Belvoir, Virginia

Bludau, Owen W., 1980, "Beachfront Restoration Using Water
Quality Programs,".Coastal Zone 180, ASCE Specialty
Conference, Hollywood, Florida

Boberschmidt, L., D. Carsten, R. Hobberger, S. Saari, 1976,
"Considerations for Environmental Impact Assessment,of
Small Structures and Related Activities as Applied to
the Chicago District," U.S. Army Corps of Engineers and
the Mitre Corp., McLean, Virginia

-165-

Brater, E. F.,-1975, "Low Cost Shore Protection for the'
Great Lakes," Lake Hydraulic Lab, University of Michigan,
Ann Arbor, Michigan

Brater, E. F., J. M. Armstrong, and M. McGill, 1974,
"Michigan's Erosion Control Program: Evaluation Report,"
Michigan Department of Environmental Resources, Ann
Arbor, Michigan

Brater, E. F., J. M. Armstrong, and M. McGill, 1977, "The
Michigan Demonstration Erosion Control Program in 1976,"
Michigan Sea Grant Program, Technical Report No. 55,
Ann Arbor, Michigan

Caldwell, Joseph, 1977, "The.Shoreline Erosion Control
Demonstration Act of 1974," Shore and Beach, 45:4, October

Caldwell, Kenneth C., 1.980, "Response to a Changing
Environment," Coastal Zone 180, ASCE Specialty
Conference, Hollywood, Florida

Candle, R. D., and W. J. Fischer, 1977, Scrap Tire Shore
Protection Structures, Goodyear Tire and Rubber Co.,
Akron, Ohio

Carter, Charles H., 1976, Lake Erie Shore Erosion, Lake Co.
Ohio: Setting, Proces .ses, and Recession Rates from 1876
.to 1973, State of Ohio, Department of Natural Resources,
Columbus, Ohio

Carter, Charles, et al, 1979, "Shore Protection Structures:
Effects on Recession. Rates and Beaches from the 1870's
to the 1970's Along the Ohio Shore of Lake Erie," Proc.
The Coastal Society, Newport, R.I.

Clark, J., 1974, "Coastal Ecosystems: Ecological Consid-
erations for Management of the Coastal Zone," The
Conservation Foundation, Washington, D.C.

Clemons, Robert, undated, The Role of Vegetation in
Shoreline Management: A Guide for Great Lakes Shoreline
Property.Owners, Great Lakes Basin Commission, Ann Arbor,
Michigan

, 1980, "Coastal Environmental Management,"
The Conservation Foundation,-Washington, D.C., FIA-4,
June

1979, "Community Erosion Protection System
Analysis," Coastal Zone Laboratory, University of
Michigan, Ann Arbor, Tech. Report No. 117

-166-

Combe, A. J. and D. W. Berg, 1974, "Guidelines for
Monitoring Shore Protection Structures in the Great
Lakes," U.S. Army Corps of Engineers, Coastal Engineer-
ing Research Center, Fort Belvoir, Virginia

Carstea, D, A. Bender, et al, 1975, "Guidelines for
Environmental Impact Assessment of Small Structures and
Related Activities in Coastal Bodies of Water," The
Mitre Corp., McLean, Virginia, Tech. Report No. MTR-6916

Carstea, D., J. Golden, and L. Thomas, 1975, "Guidelines
for the Analysis of Cumulative Environmental Effects of
Small Projects in Navigable Waters," The Mitre Corp.,
McLean, Virginia, Tech. Report No. MTR:6939

Cronin, L. E., G. Gunter, and S. H. Hopkins, 1969, "Effects
of Engineering Activities on Coastal Ecology," Office
of the Chief of Engineers, U.S. Army Corps of Engineers,
Washington, D.C.

Darseau, Elba A., Jr., 1978, "Guide for the Identification
of Activities Requiring a Corps of Engineers Permit,"
Environmental Laboratory, U.S. Army Corps of Engineers,
Waterways Experiment Station, Vicksburg, Mississippi

DeHart, Grant, 1979, "Gray's Harbor: An Example of
Regional Planning to Implement Coastal Zone Management
Programs." Proc. The Coastal Society Conference,
Newport, R.I.

DeYoung, Bruce, 1978, "Enhancing Wave Protection With
Floating Tire Breakwaters," New York Sea Grant, Cornell
University, Ithaca, New York, Information Bulletin No.
139

Eberhart, R. C. and D. A. 14auer, 1980, "Pressures on the
Edges of Chesapeake Bay: 1973-1979," Applied Physics
Laboratory, The Johns Hopkins Univeristy, Laurel,
Maryland

Eberhart, R. C., and Thomas Dolan, 1980, "Chesapeake Bay
Development Pressures: RAMS Data Base Analysis,"
Coastal Zone '80, ASCE Specialty Conference, Hollywood,
Florida

Edge, Billy, and Adrian J. Combe 111, 1978, "Low Cost Shore
Protection," Coastal Zone 178, ASCE Specialty Conference,
San Francisco, California

-167-

Edge, Billy, John G. Housely and George M. Watts, 1976,
"Low Cost Shoreline Protection," Coastal Engineering 176.,
ASCE Specialty Conference, Honolulu, -Hawaii

Edge, Billy, and Orville Magoon, 1979, "A Review of Recent
Damages to Coastal Structures," Coastal Structures 179,
ASCE Specialty Conference, Alexandria, Virginia

Ekman, Mark R., 1978, -"Erosion Control in a High Energy
Coastal Environment," Coastal Zone 178, ASCE Specialty
Conference, San Francisco, California

1978, "Environmental Areas with Development
Constraints in Northwest Pennsylvania," Office of State
Planning and Development, Harrisburg, Pennsylvania

Everts, Craig H., 1979, "Beach Behavior in the Vicinity of
Groins: Two New Jersey Field Station Examples," Coastal
Structures 179, ASCE. Specialty Conference, Alexandria,
Virginia

Gantt, L. K., 1975, "Ecological Considerations Regarding
Use of Bulkheads and Rip Rap in the Chesapeake Bay
Estuary for Erosion Control," U.S. Fish and Wildlife
Service, Washington, D.C.

Gifford, Charles A., Jeffrey A. Fisher and Todd Walton, Jr.,
1977, Bull. SUSF-SG-77-002, Florida Sea Grant

Giles, Michael L., 1977, "Evaluation of a Concrete Building
Block Revetment," Coastal Sediments 177, ASCE Specialty
Conference, Charleston, S.C.

Giles, M. L., and R. M. Sorenson, 1979, "Determination of
Mooring Loads and Wave Transmission for a Floating Tire
Breakwater," Coastal Structures 179, ASCE Specialty
Conference, Alexandria, Virginia

11 r
Graber, Peter H. F., Che Law of the Coast in a Clamshell,"
Shore and Beach, 48:4 Oct. 1980

Great Lakes Basin Commission, 1980, "Great Lakes Basin Plan:
Coastal Hazards Element and Draft Environmental Impact
Statement" (Draft)

Great Lakes Basin Commission, 1978, "Erosion/Insurance
Study," Standing Committee on Coastal Zone Management,
GLBC, Ann Arbor, Michigan

-168-

Gutman, Andrew L., 1979, "Low Cost Shoreline Protection in
Massachusetts," Coastal Structures '79, ASCE Specialty
Conference, Alexandria, Virginia

Haras, William, 1975, "Canada-Ontario Great Lakes Shore
Damage Survey," Canadian Centre for Inland Waters,
Burlington, Ontario, Tech. Report

Harrison, Samuel, 1975, Letter to Colonel R. L. Moore, U.S.
Army Corps of Engineers, Buffalo District

Healy, Robert G., ed., 1978, Protecting the Golden Shore:
Lessons from the California Coastal Commission, The
Conservation Foundation, Washington, D.C.

Herbich, J. B. and R. E. Schiller, 1976, "Shore Protection,"
Marine Advisory Bulletin, Sea Grant Publication TAMU-SG-
76-504

Hildreth, Richard G., 1980, "Legal Aspects of Coastal Hazards
Management," Coastal Zone 180, ASCE Specialty Conference,
Hollywood, Florida

Holton, James W., Jr., 1980, "General Permits: Method of
Criteria Development," Coastal Zone 180, ASCE Specialty
Conference,. Hollywood, Florida

Inman, D. L., 1976, "Man's Impact on the California Coastal
Zone," Department of Navigation and Ocean Development,
State of California, Sacramento

Inman, D. L., 1978, "The Impact of Coastal Structures on
Shorelines," Coastal Zone 178, ASCE Specialty Conference,
San Francisco, California

Inman, D. L. and J. D. Frautschy, 1966, "Littoral Processes
and Development of Shorelines," Coastal Engineering
Proc., ASCE Specialty Conference, Santa Barbara, California

1977, "Introduction to Environmental Planning for
Local Decision Makers," Bureau of Environmental Planning,
Department of Environmental Resources, Harrisburg, Pa.

Jones, D. Earl, 1978, "Housing and Related Coastal Programs:
Current Practices Offer Improved Solutions," Shore and
Beach, 46:1, Jan. 1978

Kerns 'Waldron R., 1979, "A Decision Strategy for Management
of Coastal Erosion," Proc. The Coastal Society, Newport,
R.I., Nov., 1979

-169-

Kerns, Waldron R. and Janet Scheid, 1980, "A Strategy for
Financing Coastal Erosion Control," Coastal Zone '80,
ASCE Specialty Conference, Hollywood, Florida

Kethchum, B. H., 1972, "The Water's Edge: Critical
Problems of the Coastal Zone," MIT Press, Cambridge,
Mass.

Knuth, P. D., 1978, "A Shore Structure Inventory of the
Pennsylvania and New York Portion of Lake Erie and the
Niagara River, U.S. Army Corps of Engineers, Buffalo
District, Buffalo, New York

Knuth, P. D. and R. Crowe, 1975, "Shoreline Erosion and
Flooding: Erie County," Department of Environmental
Resources, Harrisburg, Pennsylvania

Knutson, P. L., 1977, "Designing for Bank Erosion Control
With Vegetation," Coastal Sediments 177, ASCE Specialty
Conference, Charleston, S.C.

Knutson, P. L., 1977, "Summary of CERC Research on Use of
Vegetation for Erosion Control," Proc. Great Lakes
Vegetation Workshop, Great Lakes Basin Commission,
Ann Arbor, Michigan

Koerner, R. M. and J. P. Welsh, 1979, "Construction and
Gecxtechnical Engineering Using Synthetic Fabrics,"
Wiley and Son, New York, N.Y.

Koerner, R. M. and J. 11. Welsh, 1979, "Innovative.Uses of
Synthetic Fabrics in Coastal Construction," Coastal
Structures 179, ASCE Specialty Conference, Alexandria,
Virginia

Koppleman, Lee and John G. Housely, 1977, "The Shoreline
Erosion Control Act: institutional and Legal Arrange-
ments," Shore and Beach, 45:4, Oct., 1977

Kowalski, T. and N. Ross, 1975, "How to Build a Floating
Tire Breakwater," University of Rhode Island, Marine
Bulletin No. 21, Narragansett, R.I.

Kuhn, Gerald G., Elizabeth Baker and Carrie Campen, 1980,
"Greatly Accelerated Man-Induced Coastal Erosion and New
Sources of Beach Sand, San Onofre State Park and Camp
Pendleton, Northern San Diego County, California," Shore
and Beach, 48:4, Oct. 1980

-170-

Kureth, C. L., J. M. Armstrong, et al, 1980, "A Community
Approach to Coastal Erosion Protection," Coastal Zone
'80, ASCE Specialty Conference, Hollywood, Florida

Lake Hydraulics Lab. undated, "Low Cost Shore Protection
for the Great Lakes," Research Publication No. 3,
University of Michigan, Ann Arbor, Michigan

Machemehl, J. L., 1977, "An Engineering Evaluation of
Low-Cost Stabilization Projects in Brunswick County,
North Carolina," Coastal Sediments 177, Charleston, S.C.

Mandelker, Daniel R., 1.975, "Critical Area Controls: A
New Dimension in American Land Development Regulation,"
AIP Journal, Jan. 1975

Marks, William D., 1977, "A Five-Year Review of the Michigan
Demonstration Erosion Control Program," Shore and Beach,
45:4, Oct., 1977

McCartney, B. L., 1976, "Survey of Coastal Revetment Types,"
U.S. Army Corps of Engineers, Coastal Engineering
Research Center, Fort Belvoir, Virginia, Misc. Report
No. 76-7

McGillivray, Daniel G. and Brian Greenwood, 1978, "Physical
Impact Assessment and Coastal Structures," Coastal
Zone '78, ASCE Specialty Conference, San Francisco,
California

McKinney, Thomas F. et al, 1980, "New Jersey Shore
Protection Planning," New Jersey Department of
Environmental Protection

Mickelson, D. M. et al, 1977, "Shoreline Stabilization and
Bluff Stability Along Lake Michigan and Lake Superior
Shorelines of Wisconsin," Coastal Zone Management
Program, Madison, Wisconsin

Mikketsen, S. C., 1977, "The Effects of Groins on Beach
Erosion and Channel Stabilization at the Limfjord
Barriers, Denmark," Coastal Sediments 177, ASCE
Specialty Conference, ChaMi-ston, S.C.

Mitchell, James K., 1975, "Issues involved in United States
Beach Preservation and Protective Programs," Shore and
Beach, April, 1975

Noble, Ronald M., 1978, "Coastal Structures Effects on
Shorelines," Coastal Enqineering 178, ASCE Specialty
Conference, HTFFurg, Germany

-171-

Nordstrom, K. F., J. R.. Allen and P. A. Gares, 1979, "The
Effects of Groin Removal on Shoreline Stability,"
Coastal Structures `79,, ASCE Specialty IConference,
Alexandria, Virginia

Omholt, T., 1974, "Effects Of Small Groins on Shoreline
Changes on the North Shore of Suffolk County, N.Y.,"
New York Ocean Science Lab, Montauk, N.Y., No. 0028

Omholt, T., 1974, "Small Groins on the Shores of Long
Island," Shore and Beach, April, 1974

Pallet, N. and C. H. Dobbie, 1969, "The Terminal Problem
in Coast Protection," ASCE Specialty Conference, Proc.
llth Conf erence

Parker, Neill, 1980, "Barrier Islands, Beach and Coastal
Engineers," Shore and Beach, 48:4, Oct., 1980

11 1974, "Permits for Construction of Shore
Protection Works on Lake Michigan," Sea Grant Advisory
Service, University of Wisconsin

11 1973, "A Plan for Michigan's Shorelands," Mich.
Department of Natural Resources

Pilkey, Orrin H., Jr. and Orrin H. Pilkey, Sr., (undated),
"How to Live With an Island: A Handbook to Bogue
Banks, N.C.," North Carolina Department of Natural and
Economic Resources, Raleigh, N.C.

Porraz, M., J. A. Maza and M. L. Munoz, 1977, "Low Cost
Structures Using Operational Design Systems," Coastal
Sediments 177, ASCE Specialty Conference, Charleston,
S.C.

Raynor, A.*C. and R. L. Rector, 1961, "Groins on the Shores
of the Great Lakes," J. Waterways Harbor Devel., American
Soc. of Civil Engineers, 87:4

, 1979, "Resource Allocation Issues in the Coastal
Environment," The Coastal Society, Arlington, Virginia

Roberts, Wm. H., 1980, "Environmental Developmental Trade-
offs in the Coastal Zone," Draft

Roellig, D. A. and L. W. Hiipakka, 1978, "Mitigation of
Shore Damage in the Great Lakes," Coastal Zone 178,
ASCE Specialty Conference, San Francisco, California

-172-

Sanko, Peter, (undated), "Shoreline Protection Guide for
Property Owners," New York Sea Grant Advisory Service,
Albany, New York, No. NYSSGP-AS-75-001

Schiff, J. B., 19.59, "Generalities on Coastal Processes and
Protection," J. Waterways and Harbor Division, ASCE,
85:1-12

Shanks, Larry R., 1978, "Small Coastal Structures--A Review,"
Coastal Zone 178, ASCE Specialty Conference, San
Francisco, California

, 1959, "Shore Erosion in Ohio," State of Ohio,
Department of Natural Resources, Columbus, Ohio

, 1973, "Shore Erosion on the Great Lakes," Part
I, Summary Report, Environment Canada, Ottawa

197 7, "Shoreland-Floodplain Ordinance for
Sheboygan County (Wisc.)," Sheboygan County Planning and
Resources Department, Sheboygan, Wisconsin

(undated), "Shoreline Erosion: Questions and
Answers," Michigan Sea Grant Program, University of
Michigan, Ann Arbor

Shuisky, Yuri D. and Maurice Swartz, 1980, "Influence of
Beaches on Development of Coastal Erosion Slopes in the
NW Part of the Black Sea," Shore and Beach, 48:4, Oct.

Simison, E. J. et al, 1978, "Potential Shoreline Impacts
from Proposed Structures at Point Conception, California,"
Coastal Zone 178, ASCE Specialty Conference,
San Francisco

Speight, Carol, 1980, "Irresistible Forces Movable
Objects," South Carolina Wildlife, July-Aug. 1980, 27:4

Staats, David, 1981, "What You May Need to Know About
Owning Shore Property," Great Lakes Communicator, 11:5,
Great Lakes Basin Commission, Ann Arbor

Stembridge, James E., 1979, "Beach Protection Properties
of Accumulated Driftwood," Coastal Structures 179, ASCE
Specialty Conference, Alexandria, Virginia

Terich, Thomas A., 1975, "Property Owner Response to Beach
and Shore Bluff Erosion in Northern'Puget Sound," Shore
and Beach, April, 1975

-173-

Terich, Thomas A., 1978, "Beach Erosion Protection''in Puget
Sound," Coastal Zone '78, ASCE Specialty Conference,
San Francisco, California

Terich, T. A., and S. Milne, 1977, "The Effects of Wood
Debris and Drift Logs on Estuarine Beaches of Northern
Puget Sound," Department Of Geography and Regional
Planning, Western Washington University

Thomas, Bill, 1980, "Our Restless Islands," South Carolina
Wildlife, July-Aug.

Tubbs, Donald, 1974, "Landslides in Seattle," State of
Washington, Department of Natural Resources, Division
of Geology and Earth Resources, Info. Cir. No. 52

U.S. Army Cor@s of Engineers, Coastal Engineering Research
Center, 1977, Shore Protection Manual, U.S. Govt. Printing
Office

U.S. Army Corps of Engineers, Buffalo District, General
Permit for Shore Protection in Lake Erie, Buffalo
District, Buffalo, New York

U.S. Army Corps of Engineers,.1975, "Guidelines for
.Monitoring Shore Protection Structures in the Great
Lakes," Coastal Engineering Research Center, Fort
Belvoir, Virginia, Misc. Paper No. 2-75

U.S. Army Corps of Engineers, North Central Division, 1972,
"Great Lakes Shoreline Damage: Causes and Protective
measures"

U.S. Army Corps of Engineers, North Central Division, 1971,
National Shoreline Study, Great Lakes Inventory Report,
Vol. 5

U.S. Department of Commerce, National oceanic Atmospheric
Administration, 1976, Natural Hazard Management in
Coastal Areas, Washington, D.C.

Walton, Todd'L., Jr. and William Sinsabaugh, 1979, "Seawall
Design on the Open Coast," Sea Grant No. 29, State
University System of Florida

Wang, Yu-Hwa, Walter W. Howard, Ted H. Chang and Morton
Smutz, 1979, "A Field Study on the Interaction of Groin
and Sediment Transport," Coastal Structures 179
Alexandria, Virginia, ASCE Specialty Conference

-174-

White, Gilbert, et al, 1976, Natural Hazard Management in
Coastal Areas, NOAA, OCZM, Washington, D.C.

White, Gilbert, 1978, "'Natural Hazards Management in the
Coastal Zone," Shore and Beach, 46:1 Jan., 1978

Wood, Lydia, et al, 1979, "The Effectiveness of Coastal
Structures at Selected Sites in Massachusetts," Proc.
The Coastal Society, Newport, Rhode Island

Yanggen, D. A., 1981, "Regulations to Reduce Coastal
Erosion Losses," University of Wisconsin, Extension,
Wisconsin Coastal Zone Management Program, Madison,
Wisconsin

I
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I APPENDIX II
I SOME LOCAL EXAMPLES OF STRUCTURAL CONTROL
I TECHNIQUES
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-176-

Figure A-1

Located in an area off Route Five in Erie County at Woodmere,

the site has been experiencing rapid shoreline retreat and erosion

at the toe of the bluff. The principal reason is elevated water

levels since 1973. As can be seen in the photo, the property owner

has attempted to mitigate his losses by the application of debris

consisting of tree trunks, concrete rubble, and stone. Some

attempt to confine the debris is clearly apparent. A concrete

wall has failed. This is a rather typical example of individual

response to the erosion problem. Generally the high cost of

proper design and construction is beyond the means of this prop-

erty owner as it is for so many others. The result of such

placement is visual blight'and a very temporary ameilioration

of the problem. (See section I)

-178-

Figure A-2

Located in the Baer Farm Estate, this cottage, like so

many others in the area, has been increasingly exposed to storm

waves and high water levels.. That the forces associated with

storm waves is not understood is the rudimentary structure

(bulkhead?) constructed as a defense measure. The structure.did

not live past the first storm. Constructed of railroad ties,

this type of defensive measure is a total waste of time. Per-

haps it gave the owner a small measure of comfort in the knowl-

edge that he tried something. It certainly reveals a lack of

information that should now be more generally available.

-180-

Figure A-3

As mentioned in Section II, groins are the preferred type

of remedial measure used in Erie County to prevent erosion of

beach materials and to protect property. This series of groins was

constructed by property owners in Millcreek Township to protect

beaches and to preserve a narrow strand of developable land..

High water levels and incremental losses have put these cottages

in jeopardy. At the time the buildings were constructed water

levels were far below present levels burying a significant

portion of beach. In addition to the groins, three of the owners

have constructed bulkheads as minimum protection against anything
larger than a five foot wave*event.

. . . . . . . . . .

59-1 1 ml

_183-

Figure A-4

The structure at the edge of the bluff is clearly in

imminent danger of loss to bluff recession. Coupled with the

need to provide a minimum recreational beach at the camp (Eriez-

on-the-Lake) a groin was constructed to accumulate sand. It is

apparent that the groin is serving to accumulate some sand pro-

ducing a measure of protection at the toe of the bluff. However,

equally apparent is the starved condition of the beaches down-

drift (left of the groin in the picture). The beaches downdrift

exhibit..wave cutting in the foreshore. The effects are not as

pronounced as they might be. While the bluff downdrift is receding

the rate is not out of character with the bluff being protected

by the groin.

7773

-185-

Figure A-5

This gabion was constructed at Kelso Beach, Millcreek

Township as a low-cost, short-term solution to beach erosion.

The baskets were filled with native stone. The gabion sur-

vived one season and was not replaced by the owner. While

the low cost of such structures is attractive, the user most

often does not maintain the structure over time. The obvious

explan ation is that the relative non-success of such struct-

ures beyond one season does not justify reconstruction or

maintenance. In the meantime, the effects produced on shore

equilibrium are significant. (See Section II)

M-9-4, wl,
loom a kiwis
-21

-187-

Figure A-6

Also located at Kelso Beach is this cast concrete groin.

The structure is tied back in the backshore and has withstood

several seasons of storm waves. A possible explanation for its

success is the generally good supply of sand in the drift

system at this location. In addition, the presenece of offshore

bars serve to "trip" storm waves and reduce the energy receipt

on shore.

44-

J'A

@ ft@
fl,i

_189-

Figure A-7

These bulhead and groin combinations are the rpsult of

individual response by the owners to protect year-round residences

at the foot of Powell Avenue in Millcreek Township. They are

generally haphazard affairs accomplished with limited dollars.

The predominate material behind the groins is shingle-sized

fragments eroded*from the bedrock at or near water level on site

and up drift. The accumulation of this larger sized material

has assisted in protecting valuable property perched precariously

at the zone between the high.bluffs and the beach area. It is

an area of high risk as lake levels continue high. Structural

response is the only response available. Cost is the deterrent.

_191-

Figure A-8

Located near the mouth of Godfrey Run in Girard Township,

the structure is fairly typical of groins constructed in the

western part of the county. The initial structure was poured in

place and subsequently improved by extensions of height and

length with pre-cast concrete blocks. An accumulation of mater-

ial can be seen on the updrift side. The negative influences

are apparent on the downdrift side. A starved beach has enabled

storm waves to attack the base of the bluff, destroying stability.

Such structures almost always cause negative impacts downdrift.

See Section II.

em 7.

-193-

Figure A-9

Attempts to mitigate the downdrift effects of groins

consist of placing rubble on the downdrift side to prevent

losses of beach material. The procedure illustrates that tamper-

ing with beach equilibrium is going to result in negative impact

followed by additional costs either on-site or on sites down-

drift. (See Section II)

-195-

Figure A-10

A more innovative approach to bulkheading was attempted at

Freeport, Northeast Township. The barrels are tanks cut in half,

tied together, firmly founded, and backfilled. Bulkheads in

low lying areas with no pressure from mass wasting behind, have

a good chance of survival if properly designed. See Section III.

This particular structure has survive eight seasons with a minimum

of maintenance consisting og backfilling the structure. As

stated in Section I, such structures preclude beach building at

the lakeward side. The structure then, must be strong enough

to survive without the protection of a well developed beach.

-197-

Figure A-11

At the Gunkle residence in Girard Township a groin con-

structed by the up drift property owner has produced a negative'

impact on the Gunkle property. Combined with a starved beach,

bluff instability has produced a hazard to the high-cost dwel-

ling located at the edge of the bluff crest. Unfortunately,

high bluff conditions preclude remedial measures on the bluff

face. One alternative would be to construct an additional groin

on the downdrift side of the property. It is not known if there

is a sufficient supply of sand in the system to feed an additional,

structure. See Section II.

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