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

                    hio
                    epartment of
                    atural
                   esources                                       COASTAL ZONE
                                                                  INFORMATION' CENTER

                                            COASTAL HAZARDS:

                                       RECESSION, EROSION AND FLOODING

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                 1977

                                                                                                Ohio Coastal Zone Management Program

                   COASTAL ZONE
                   INFORMATION CENTER

                                             STATE OF OHIO
                                   DEPARTMENT OF NATURAL RESOURCES
                                           DIVISION OF WATER
                                   COASTAL ZONE MANAGEMENT SECTION

                         COASTAL HAZARDS: RECESSION, EROSION AND FLOODING

                                          prepared for the
                                   Coastal Zone Management Program
                                                  by
                              Charles H. Carter and Bruce E. McPherson

                                               PrOPOZt1? Of CSC Library
                         LiEPARTMENT.OF COMMERCE NOAA
                    COASTAL SERVICES CENTER  October 1977
                    2234 SOUTH HOBSON AVENUE
                    CHARLESTON , SC 29405-2413

                           This publication was financed in part by a  federal
                           grant from the Office of Coastal Zone Management,
                           National Oceanic and Atmospheric Administration,
                           under the provision of Section 305 of the Coastal
                           Zone Management Act of 1972 (P.L. 92-583).

                                        Alm   AOL
                                        UZIG            1 L EC 11
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         0  W

            @15        JAMES A. RHODES, Governor ROBERT W. TEATER, Director WAYNE S. NICHOLS, Chief

                                                   CONTENTS

                                                                                       page
                         SHORELINE RECESSION AND EROSION

                            Introduction   . . . . . . . . . . . . . . . . . .             I

                            Shore Processes   . . . . . . . . . . . . . . . . .

                         Lucas County

                            Setting . . . . . . . . . . ... . . . . . . . . .              3

                            Shore Processes   . . . . . . . . . . . . . . . . .            3

                            Shoreline Changes   . . . . . . . . . . . . . . . .            4

                            Structures   . . . . . . . . . . . . . . . . . . .             4

                            Beaches . . . . . . . . . . . . . . . . . . . . .              5

                            Recession Rates 1877-1940     . . . . . . . ... . . .          5

                            Recession Rates 1940-1973     . . . . . . . . . . . .          5

                            Recession Rates 1877-1940 to 1940-1973        . . . . .        6

                         Ottawa County
                            Setting .. . . . . . . . . .. . . . . . . . . . . .            7
                            Shore Processes   . . . . . . . . . . . . . . . . .            7
                            Shoreline Changes   . . . . . . . . . . . . . . . .            8
                            Structures   . . .  . . . . . . . . . . . . . . . .            8

                            Beaches . . . . . . . . . . . . . . . . . . . . .              9

                            Recession Rates 1877-1939     . . . . . . . . . . . .          9
                            Recession Rates 1939-1973     . . . . . . . . . . .. ..      .10

                            Recession Rates 1877-1939 to 1939-1973        . . . . .       10

                         Erie and Sandusky Counties
                            Setting . . . . . . . . . . . . . . . . . . . . .             11

                            Shore Processes   . . . . . . . . . . . . . . . . .           12

                                                        iii

                        Shoreline Changes  . . . . ... . . . . . . . . . .       12

                        Structures  . . . . . . . . . . . . . . ... . . .        12

                        Beaches . . . . . . . . . . . . . . . . . . . . .        13

                        Recession Rates 1877-1937   . . . . . . . . . . . .      14

                        Recession Rates 1937-1973   . . . . . . . . . . . .      14

                        Recession Rates 1877-1937 to 1937-1973     . . . . .     14

                        Present and Future Considerations   . . . . . . . .      15

                      Lorain County

                        Setting . . ... . . . . . . . . . . . . . . . . .        17

                        Shore Processes  . . . . . . . . . . . . . . . . .       17

                        Shoreline Changes  . . . . . . . . .   . . . . . . .     17

                        Structures  . . . . . . . . . . . . . . . . . . .        18

                        Beaches . . . . . . . . . . . . . . . . . . . . .        19

                        Recession Rates 1876-1937   . . . . . . . . . . . .      19

                        Recession Rates 1937-1973   . . . . . . . . . . . .      19

                        Recession Rates 1876-1937 to 1937-1973     . . . . .     19

                      Cuyahoga County

                        Setting . . . . . . . . . . . . . . . . . . . . .        21

                        Shore Processes  . . . . . . . . . . . . . . . . .        .21

                        Shoreline Changes  . . . . . . . . . . . . . . . .       21

                        Structures  . . . . . . . . . . . . . . . . . . .        22

                        Beaches . . . . . . . . . . . . . . . . . . . . .        22

                        Recession Rates 1876-1937   . . . . . . . . . . . .      23

                        Recession Rates 1937-1973   . . . . . . . . . . . .      23

                        Recession Rates 1876-1937 to 1937-1973                   23

                                                    iv

                        Lake County

                           Setting . . . . . . . . . . . . . . . . . . . . .       25

                           Shore Processes . . . . . . . . . . . . . . . . .       27
                           Shoreline Changes . . . . . . . . . . . . . . ....      27

                           Recession Rates 1876-1937  . . . . . . . . . . . .      28

                           Recession Rates 1937-1973  . . . . . . . . . . . .      29

                        Ashtabula County

                           Setting . . . . . . . . . . . . . . . . . . . . .       31

                           Shore Processes . . . . . . . . . . . . . . . . .       31

                           Shoreline Changes . . . . . . . . . . . . . . . .       31
                           Structures        I. . . . . . . . . . . . . ... .      3 2

                           Beaches . ... . . . . . . . . . . . . . . . . . .       32

                           Recession Rates 1876-1938  . . . . . . . . . . . .      33

                           Recession Rates 1938-1973  . . . . . . . . . . . .      33

                           Recession Rates 1876-1938 to 1938-1973     . . . . .    33

                        Potential Protection Considerations    . . . . . . . .     35

                        FLOODING

                           Introduction  . . . . ... . . . . . . . . . . . .       37

                           Geological History   . . . . . . . . . . . . . .        37

                           Natural Attraction   . . . . . . . . . . . ... . .      37

                           Riverine Flooding . . . . . . . . . . . . . . . .       38

                           Lake Flooding . . . . . . . . . . . . . . . . . .       39

                           Flood Plain Information  . . . . . . . . . . . . .      41

                           Management Considerations  . . . . . . . . . . .        42

                                                      v

                            SHORELINE RECESSION AND EROSION

                   Introduction

                        The shoreline erosion section of this report presents
                   a summarized county by county description of the Ohio shore
                   of Lake Erie including information on the rates at which
                   the shore of Lake Erie is receding. It is based on the data
                   compiled by the Ohio Department of Natural Resources, Divi-
                   sion of Geological Survey for detailed shore erosion
                   investigation reports to be published over the next two
                   years. Many natural, cultural, and manmade features along
                   the shore affect the rate of erosion and the natural
                   littoral deposition process. This information facilitates
                   decisions and planning related to shore erosion. Such
                   decisions are necessary because of increased development
                   along the shore and the greater probability of increased
                   damage. Erosion not only causes loss of property, but also
                   results in sedimentation of silt and clay which contributes
                   to the eutrophication of Lake Erie.

                        Maps and photographs from three years--1876, 1937, and
                   1973--were selected for use in calculating the rate at
                   which erosion has occurred alon- the south shore of Lake Erie.
                   The 1876 maps are the first detailed maps of the entire
                   Ohio shore of Lake Erie. The 1937 photographs are one of
                   the first series of aerial photographs taken of the entire
                   Ohio shore of Lake Erie, and the 1973 photographs are one
                   of the latest series.

                        The recession rate information provided in this report
                   is described according to various rate classes such as slow,
                   moderate, rapid, etc. The quantitative equivalents of these
                   rate classes are as indicated below.

                          Recession Rate Class           Rate  (Ft/yr)
                               Very slow                       <1
                               Slow                            1-3
                               Moderate                        3-5
                               Rapid                           5-7
                               Very Rapid                      7-9

                   Shore Processes

                        Shore erosion, the loss of shoreland, can be related to
                   many processes, but along the Lake Erie shore, there are two
                   principal shore erosion processes: wave erosion and mass
                   wasting. Of the two processes, wave erosion is by far the
                   more significant. These processes erode the Lake shore at
                   different rates because of two primary factors: the physical
                   setting and the weather. Variation in.recession rates among

                                                  1

               different reaches along the shore and through time generally
               can be related to these two factors..

                    Surface waves, which are generated by wind blowing across
               the lake, are the principal cause of recession along the Lake
               Erie shore because waves contain a great deal of energy that
               is released when the waves deform and break. Although some of
               the energy is returned to the lake through reflection and
               other types of wave-related movement, much of the energy is
               expended in wave erosion of the nearshore, beach and shoreline,
               and shore zones.

                    The effect of nearshore slope on wave energy can be
               looked at in this general way: (1) wave energy is related
               directly to wave height; (2) waves deform and break (lose
               their height) when the water depth is about one to two times
               the wave height; (3) therefore the gentler the nearshore slope,
               the farther offshore waves break and the greater the decrease
               in wave energy reaching the shoreline. Once the waves reach
               the shoreline a wide beach will absorb most of the wave energy,
               but along the stretches with narrow beaches a much greater
               proportion of the wave energy will reach the shore.

                    Lastly, because of the nearly continuous removal of
               slumped or inplace material, which acts as a resisting moment
               at the base of the slope or bluff, the shore bluff or slope
               does not at any time reach a long-term equilibrium. Therefore,
               recession is continuous.

                    Mass wasting is basically the downslope movement of
               material by gravitational stress. Along the Ohio shore of Lake
               Erie the principal mass-wasting processes are block falls,
               rotational slumps, debris flows, and piping.

                    Block falls, which are the relatively free-falling move-
               ment of coherent material, are caused by wave erosion
               undercutting the base of a bluff. Rotational slumps, which
               are a shearing and rotary movement of material along a curved
               slip surface, appear to be controlled by laminated clay zones
               within or above the till. When a clay zone becomes lubricated,
               either from water updip or from surface water percolating down
               along joint planes, the zone acts as a slip plane upon which
               the shore material slumps. Debris flows, which are the down-
               ward movement of a mass of incoherent material, are most
               pronounced where there are interbedded sands. Water percolat-
               ing down from the overlying sands and/or running along the
               sand-clay interface saturates the clay. This increase in
               moisture reduces the internal shear resistance of the clay and
               this, as well as the weight of the overlying sand, causes the
               clay to deform and flow. Piping, which is erosion by percolat-
               ing water, is common along sand-clay contacts. Water flowing
               through an overlying sand layer is concentrated at the clay
               contact; the consequent decrease in the shear strength of the
               sand at the contact causes the sand to collapse.

                                                2

                                           LUCAS COUNTY

                  Setting

                       The sparsely to densely built-up Lucas County shore
                  fronts 23 miles (37 km) of the westernmost portion of Lake
                  Erie and lies between Michigan to the northwest and Ottawa
                  County to the east. Shore deposits consisting largely of
                  glaciolacustrine clay make up the low relief banks of about
                  5 feet (1.5 m) that border Maumee Bay, whereas sand and
                  marshes make up the low relief slopes of about 5 feet (1.5 m)
                  that border Cedar Point to the Lucas-Ottawa County line
                  (western basin shore). Sand beaches are small or nonexistent
                  along the Maumee Bay shore, whereas discontinuous beaches
                  front 44% of the open lake shore. In addition to the beaches,
                  shore protection structures or manmade fill fronts much of
                  the Maumee Bay shore and some of the open lake shore, parti-
                  cularly in front of Reno Beach. Over 244 shore-protection
                  structures were inventoried in 1973. The nearshore slope is
                  gentle along the entire county; the average water depth
                  500 feet (152 m) offshore at a lake-level elevation of 570.0
                  feet is about 4 feet (1.2 m) in Maumee Bay and about 7 feet
                  (2.1 m) in the open lake. The nearshore bottom, within
                  2,000 feet (610 m) of shore, consists of mud and/or glacio-
                  lacustrine clay along Maumee Bay and sand and/or
                  glaciolacustrine clay along the western basin shore. The
                  sand for the most part is no more than 5 feet (1.5 m) thick.

                  Shore Processes

                       Storm waves appear to be the principal cause of erosion
                  along the Lucas County shore. Wave erosion removes in-place
                  and slumped material near lake level, thus maintaining an
                  unstable bank or slope. Lake level is a major factor in
                  this process. The higher the lake, the closer the waves
                  break to the shore and the.greater the wave energy expended
                  on the shore deposits, resulting in greater recession rates.

                       Mass wasting follows wave erosion in the glaciolacustrine
                  clay deposits along Maumee Bay. Block falls are fairly
                  common in this cohesive shore deposit; failure of the clay
                  blocks takes place days, weeks, or even months after wave
                  erosion.

                       Inundation (flooding) is a major problem along most of
                  the Lucas County shore because of low relief and location at
                  the-western end of the lake. Northeast storms generated by
                  low pressure systems passing to the south are largely
                  responsible for the wind setup which can reach several feet
                  above the lake's still-water level. Northeast storms in
                  combination with record high lake levels, were responsible
                  for the damaging floods in late 1972 and in 1973.

                                                3

               Shoreline Changes

                    The principal change in the Luc as County shore from 1877
               to 1973 has been the increase in unevenness of the shore. The
               1877 shore, in general, had a fairly even, uniform shape,
               whereas the 1973 shore has a much more uneven, nonuniform
               shape, particularly in the more intensely developed areas. The
               change in shape can be related directly to manmade structures--
               these structures are also largely responsible for the changes
               in beach size and distribution.

               Structures

                    In 1877 waves impinged upon a largely natural Lucas County
               shore. However, since the construction of manmade structures
               the effect of the waves has been altered. The structures,
               largely by disrupting the longshore drift of sand and/or by
               armoring the shore, have caused a decrease in the recession
               rates along some stretches and at the same time have caused
               an increase in the recession rates along other stretches.

                    Stickout structures--largely groins and jetties--by
               modifying the longshore drift of sand, have had a great
               influence on shoreline changes and recession rates along the
               western basin shore; however, along the Maumee Bay shore these
               structures have had little effect because of the lack of sand.
               Entrapment of sand on the updrift side of a structure results
               in a wider beach and a gentler nearshore slope; loss of sand to
               the adjacent downdrift shore results in a narrower beach and a
               steeper nearshore slope. The increase in beach width and
               decrease in the nearshore slope on the updrift side reduce the
               amount of wave energy impinging upon the shore and cause a
               decrease in the recession rate; on the downdrift side the
               decrease in beach width and increase in nearshore slope in-
               crease the amount of wave energy impinging upon the shore,
               causing an increase in the recession rate. Particularly note-
               worthy among the stickout structures for their effect on the
               shore are the ones at Lakemont Landing and west of Crane Creek
               State Park.

                    Parallel structures--seawalls and breakwaters--have
               reduced erosion along the Maumee Bay and western basin shore
               by protecting the base of the shore. The most notable examples
               of this type of protection are along the stretches fronting
               Point Place and Oregon on Maumee Bay and between Wards Canal
               and Lakemont Landing along the western basin. Unlike the
               stickout structures, the parallel structures, which consist
               largely of seawalls, do not appear to have a detrimental effect
               on the adjacent shore because these structures do not directly
               affect the longshore transport of sand. In general, in the
               late period, along stretches where there is a concentration of
               structures, the recession rate is slower than that of the early
               period, when there were fewer structures.

                                                4

                   Beaches

                        Nearly continuous, but narrow, beaches front the western
                   basin shore; beaches are essentially nonexistent in Maumee
                   Bay. In general, the stretches with the largest beaches,
                   such as the stretch fronting Crane Creek State Park and the
                   stretch east of Lakemont Landing, have low recession rates.
                   On the other hand, where there are narrow beaches less than
                   50 feet wide (15.2 m) in combination with an unprotected
                   shore or where the beaches were eroded away--as along stretches
                   to the west (downdrift) of Crane Creek State Park and the
                   stretch downdrift of Lakemont Landing--the recession rates
                   are high.

                   Recession Rates 1877-1940

                        The modal recess ion rate was between 5-7 ft/yr (1.5-2.1 m)
                   and the range in recession rates was very slow, less than
                   1 ft/yr (A m), to'13-15 ft/yr (3.9-4.5 m) along the western
                   basin shore; the modal recession rate was very rapid,
                   7-9 ft/yr (2.1-2.7 m), and the range in recession rates was
                   very slow to 9-11 ft/yr (2.7-3.3 m) along the Maumee Bay
                   shore. In general, the principal factor contributing to the
                   high rates along both the western basin shore and the Maumee
                   Bay shore is the type of shore deposit. The sand making up
                   the western basin shore has no cohesive resistance to surface
                   waves, and once the glaciolacustrine clay along the Maumee-
                   Bay shore becomes weathered it offers only slight resistance
                   to surface waves. The basic reasons for the lower recession
                   rate in sand is that the beaches can build back up given an
                   adequate sand supply and/or a lower lake level; the cohesive
                   deposits cannot do this.

                   Recession Rates 1940-1973

                        The modal recession rate was very slow and  the range in
                   recession rates was very slow to 13-15 ft/yr (3.9-4.5 m) along
                   the western basin shore; the modal recession rate was slow
                   and the range in recession rates was very slow to 17-19 ft/yr
                   (5.1-5.7 m) along the Maumee Bay shore. Overall, the princi-
                   pal factor contributing to the low recession rates in this
                   period is the presence of the manmade structures; high
                   recession rates have taken place along unprotected stretches
                   fronting the easily eroded sand and glaciolacustrine clay
                   deposits.

                                                 5

              Recession Rates 1877-1940 to 1940-1973

                   For the Lucas County shore (the reaches between the Ottawa-
              Lucas County line to Cedar Point and along Maumee Bay) the
              overriding factor contributing to the decrease in the modal
              recession rate as well as the overall decrease in the length
              of the shore, which underwent recession at the highest reces-
              sion rates, is the presence of manmade structures. The
              increased number of structures, as well as the greater
              length of shore protected by these structures, is responsible
              for the decrease in the modal recession rates as well as for
              the general decrease in shore length receding at high reces-
              sion rates.

                                                6

                                            OTTAWA COUNTY

                  Setting

                       The sparsely to densely built-up Ottawa County shore
                  fronts about 73 miles (117 km) of shoreline between Lucas
                  County to the west and Erie and Sandusky Counties to the east
                  and south. The shore consists largely of low relief, about.
                  5 foot (1.5 m) slopes made up of sand and marsh between the
                  Lucas-Ottawa County line to the Port Clinton area; the shore
                  consists largely of rock which reaches 50 feet (15.2 m) in
                  height from the Port Clinton area around Catawba Island to
                  the Marblehead lighthouse (including the Bass Islands); and
                  the shore consists largely of 5 to 10 foot (1.5-3.0 m) high,
                  till and glaciolacustrine clay banks south of the lighthouse
                  and along Sandusky Bay except for Bay Point. Sand beaches
                  front much of the shore from the Lucas-Ottawa Countv line to
                  the Port Clinton area; for the remainder of the county
                  beaches front small coves or are nonexistent except for two
                  prominent exceptions: the East Harbor State Park area and
                  Bay Point. In addition to the beaches, shore-protection
                  structures front much of the county shore, particularly along
                  the more intensively developed stretches made up of sand,
                  till, or glaciolacustrine clay. Over 995 shore protection
                  structures were inventoried in 1973. The nearshore slope is
                  variable. The average water depth 500 feet (152 m) offshore
                  at a lake level elevation of 570.0 feet is about 3 feet (.9 m)
                  between the Lucas-Ottawa County line and the Port Clinton
                  area; variable, a range of about 2-20 feet (.6-6 m) along
                  Catawba Island, Marblehead, and the Bass Islands; and about
                  4 feet (1.2 m) along Sandusky Bay. The nearshore bottom,
                  within 2,000 feet (610 m) of shore, consists primarily of sand
                  and glaciolacustrine clay between the Lucas-Ottawa County line
                  and the Port Clinton area; of sand, mud, and/or rock along
                  Catawba Island, Marblehead, and the Bass Islands; and of mud
                  along Sandusky Bay.

                  Shore Processes

                       Storm waves appear to be the principal cause of erosion
                  along the Ottawa County shore. Wave erosion removes in-place
                  and.slumped material near lake level, thus maintaining an
                  unstable bank or slope. Lake level is a major factor in this
                  process. The higher the lake, the closer the waves break to
                  the shore and the.greater the wave energy expended on the
                  shore deposits; consequently, the greater the recession rates.

                       Mass wasting follows wave erosion in the till and
                  glaciolacustrine deposits along Sandusky Bay as well as in
                  places north and east of the Port Clinton area. Block falls
                  are common in these cohesive deposits, with failure taking
                  place days, weeks, and even months after wave erosion.

                                                 7

    		Flooding is a major problem along the Ottawa County shore
    	from the Lucas-Ottawa County line to Port Clinton and along
    	Sandusky Bay, because of low relief and location at the western
    	end of the lake.  Northeast storms generated by low pressure
    	systems passing to the south are largely responsible for the
    	wind setup which can reach several feet above the lake's still-
    	water level.  Northeast storms in combination with record high
    	lake levels were responsible for the damaging floods in late
    	1972 and 1973.

    	Shoreline Changes

    		The principal change in the Ottawa County shore from 1877 or
    	1939 to 1973 has been the increase in unevenness of the shore.
    	The early shore, particularly from the Lucas-Ottawa County line
    	to Rock Ledge and along Sandusky Bay, was essentially continuous
    	and had a fairly even, uniform shape, whereas the 1973 shore is
    	discontinuous in places and has a much more uneven, nonuniform
    	shape.  These changes can be related to manmade structures.
    	These structures are also largely responsible for the changes
    	in beach size and distribution.

    	Structures

    		In 1877 waves impinged upon a largely natural Ottawa County
    	shore.  However, since the construction of manmade structures
    	the effect of the waves has been altered.  The structures,
    	largely by disrupting the longshore drift of sand and/or by
    	armoring the shore, have caused a decrease in the recession
    	rates along some stretches and at the same time have caused
    	an increase in the recession reates along other stretches.

    		Stickout structures--largely groins and jetties--by
    	modifying the transport of sand, have had a great in fluence
    	on shoreline changes and recession rates along the western
    	basin shore.  However, along the Sandusky Bay shore, these
    	structures have had little effect because of the lack of sand.
    	Entrapment of sand on the updrift side of a structure results
    	in a wider beach and a gentler nearshore slope; loss of sand
    	to the adjacent downdrift shore results in a narrower beach
    	and a steeper nearshore slope.  The increase in beach width
    	and decrease in the nearshore slope on the updrift side
    	reduce the amount of wave energy impinging upon the shore
    	and cause a decrease in the recession reate.  On the down-
    	drift side the decrease in beach width and increase in
    	nearshore slope increase the amount of wave energy inpinging
    	upon the shore, causing an increase in the recession rate.
    	These structures have had the greatest effect along the
    	shore from the Lucas-Ottawa County line to Rock Ledge.
    	Stickout structures particularly noteworthy for their effect
    	on the shore are the ones at Turtle Creek (which
    	interrupts the net west-to-east drift).

    							8

                        Parallel structures--seawalls and breakwaters--have
                   reduced erosion along several Ottawa County stretches by
                   protecting the base of the shore. The most notable examples
                   of this type of protection are along the stretches fronting
                   Rock Ledge east of Port Clinton and Hickory Grove along
                   Sandusky Bay. Unlike stickout structures, parallel structures
                   (which consist largely of seawalls) do not appear to have a
                   detrimental effect on the adjacent shore because these
                   structures do not directly affect the longshore transport of
                   sand. In general, in the late period, along stretches where
                   there is a concentration of structures, the recession rate
                   is slower than that of the early period, when there were
                   fewer structures.

                   Beaches

                       Narrow, but nearly continuous beaches lie between the
                   Lucas-Ottawa County line and Rock Ledge; the widest beaches
                   front the East Harbor and Bay Point areas. In general, along
                   the shore fronted by beaches, the stretches with the widest
                   beaches--such as the ones on the updrift side of the jetties
                   at Turtle Creek and LaCarpe Creek, as well as East Harbor
                   and Bay Point--are characterized by low recession rates. On
                   the other hand, where there are narrow, less than 50 feet
                   wide,(15 m) beaches in combination with an unprotected shore
                   or where the beaches were eroded away--as along stretches
                   downdrift of the jetties at Turtle Creek and LaCarpe Creek
                   or along the stretch east of Sand Beach--the recession rates
                   are high.

                   Recession Rates 1877-1939

                       The modal recession rate was very slow, less than 1 ft/yr
                   (.3 m), and the range in recession rates was very slow to
                   9-11 ft/yr (2.7-3.3 m) along the six reaches for which 1877
                   maps were prepared--the reaches along the mainland shore from
                   the Lucas-Ottawa County line to Bay Point. In general, the
                   principal factor contributing to the low rates.along the sand
                   shore west of the Rock Ledge-Port Clinton area was an adequate
                   sand supply; the beaches can build back up given an adequate
                   sand supply and/or a lower lake level. Along the shore from
                   Rock Ledge to Bay Point it is the resistance of the rock to
                   erosion which contributes to low recession rates. The stretches
                   of shore which receded at the highest rates are made up of
                   the least resistant deposits (sand, till, or glaciolacustrine
                   clay).

                                                 9

              Recession Rates 1939-1973

                   The modal recession rate was very slow and the range in
              recession rates was very slow to greater than 19 ft/yr (5.7 m).
              The highest recession rates are found along the shore made up
              of sand, till, or glaciolacustrine clay, whereas the lowest
              recession rates are found along the shore composed of rock or
              fronted by wide beaches or manmade structures.

              Recession Rates 1877-1939 to 1939-1973

                   For the reaches that can be compared (between the Lucas-
              Ottawa County line and Bay Point) the overriding factor
              contributing to the higher recession rates (as well as the
              overall increase in shore length which underwent recession
              at the highest rates) appears to be the high lake periods in
              the early 1950's and 1970's in concert with northeast storms.
              The much greater wave energy reaching the relatively long
              unprotected, easily erodable stretches of shore composed of
              sand, till, or glaciolacustrine clay has caused the shore to
              recede more rapidly in the 1939-1973 period.

                                               10

                                     ERIE AND SANDUSKY COUNTIES

                   Setting

                       The physiographically diverse shore of Erie and Sandusky
                   Counties lies along Lake Erie in north-central Ohio. The
                   mainland shore extends from the Lorain-Erie County line to
                   the Cedar Point jetty, a distance of about 21 miles (33 km).
                   It consists (from east to west) of bluffs and slopes of till
                   with a relief of 20 to 30 feet (6-9 m); bluffs, slopes and
                   banks of till and glaciolacustrine clay with a relief of 5 to
                   10 feet (1.5-3 m); and sand dunes with a relief of 10 feet
                   (3 m) along the Cedar Point spit. Manmade shore-protection
                   structures, which number more than 172, front these deposits
                   along the shore. Adjacent to the structures are beaches
                   which form a discontinuous band all along the shore. The
                   beaches have an average width of less than 50 feet (15.2 m).
                   except for the ones updrift (east of) and adjacent to the
                   sizeable jetties at Huron and Cedar Point. The average water
                   depth 500 feet (152 m) offshore at a lake level elevation of
                   570.0 feet is about 5 feet (1.5 m) along the eastern one-third
                   of the shore and increases to about 7 feet (2.1 m) to the west.
                   From the Lorain-Erie County line to the Cranberry Creek area
                   the bottom deposits to at least 2,000 feet (610 m) offshore
                   consist of sand and/or shale. Farther to the west the sand
                   at the shoreline grades into silt and finer deposits off-
                   shore. These noncohesive deposits for the most part cap
                   till or glaciolacustrine clay, which caps rock.

                       The south shore of Sandusky Bay, which extends from the
                   Cedar Point causeway to Raccoon Creek, a distance of 23 miles
                   (37 km), consists (where not made up of manmade fill) of
                   banks.of glaciolacustrine clay with a relief of 5 to 10 feet
                   (1.5-3 m). Manmade shore-protection structures (excluding
                   the nearly totally protected shore fronting the city of
                   Sandusky from the causeway to Mills Creek) front the small
                   communities along the shore. Beaches are narrow to non-
                   existent. The average water depth 500 feet (152 m) offshore
                   at a lake level of 570.0 feet is about 3 feet (.9 m). The
                   bottom, except for a band of glaciolacustrine clay which
                   borders the shore, is made up of mud; the mud caps glacio-
                   lacustrine clay.

                       Kelleys Island, which has a shoreline distance of about
                   11 miles (18 W, consists of banks of limestone-dolomite and
                   till which have a relief of from 5 to 20 feet (1.5-6 m). Man-
                   made shore-protection structures are few in number, as are the
                   narrow gravel beaches. The average water depth 500 feet
                   (152 m) offshore at a lake level of 570.0 feet is about 9
                   feet (2.7 m). The nearshore bottom is made up of rock or
                   poorly sorted sediment consisting of gravel, sand, silt,,and
                   clay-size particles.

               Shore Processes

                    Storm waves appear.to be the principal cause of erosion
               along the shore of Erie and Sandusky Counties. Wave erosion
               removes in-place and slumped material near lake level, thus
               maintaining an unstable bluff or slope. Lake level is a major
               factor in this process. The higher the lake, the closer the
               waves break to the shore and the greater the wave energy ex-
               pended on the shore deposits; consequently, the greater the
               recession rates.

                    Mass wasting follows wave erosion. Falls, slumps, and
               flows are most common where there are stratigraphic or
               structural differences such as bedding planes, zones of lami-
               nated clay within the till, or joints. Because of the
               largely cohesive nature of the shore deposits, failure of a
               bluff, slope, or bank may take place days, weeks, or even
               months after wave erosion.

               Shoreline Changes

                    The principal change in the shore of Erie and Sandusky
               Counties from 1877 to 1973 has been the increase in the
               unevenness of the shore, specifically along the Sandusky Bay
               and Lorain-Erie County line to Cedar Point (mainland) reaches.
               The shape of the 1877 shore, with the Vermilion, Huron, and
               Sandusky areas as exceptions, had a relatively even, uniform
               outline, whereas by 1973 the shape of the shore was uneven
               and nonuniform. The changes in shape can be related directly
               to manmade structures. These structures are also largely
               responsible for the changes in beach size and distribution.

               Structures

                    In 1877 waves impinged upon a largely natural Erie and
               Sandusky Counties shore. Wave erosion and subsequent mass
               wasting of the unprotected shore provided sand and gravel to
               form a nearly continuous ribbon of coarse-grained sediment
               along the shore in the beach and shoreline and nearshore
               zones, especially along the mainland shore. Wave erosion
               and mass wasting are continuing today, but, because of the
               manmade structures that have been built along the shore, the
               effect of the waves has been altered. The structures,
               largely by disrupting the longshore drift of sand and/or by
               armoring the shore, have caused a decrease in the recession
               rates along some stretches and at the same time have caused
               an increase in the recession rates along other stretches.

                    Stickout structures--largely groins and jetties--by
               modifying the longshore drift of sand, have had the greatest
               influence on shoreline changes and recession rates along the

                                               12

                   mainland shore.  Entrapment of sand on the updrift side of a
                   structure results in a wider beach and a gentler nearshore
                   slope. The increase in beach width and decrease in the near-
                   shore slope on the updrift side reduce the amount of wave
                   energy impinging upon the shore and cause a decrease in the
                   recession rate; on the downdrift side the decrease in beach
                   width and increase in nearshore slope increase the amount of
                   wave energy impinging.upon the shore, causing an increase in
                   the recession rate. These changes are most readily seen
                   between Vermilion and Huron, where unprotected stretches just
                   downdrift of the larger stickout structures show moderate
                   recession rates, and stretches just updrift of the structures
                   have very slow recession rates.

                       Parallel structures--seawalls and breakwaters--have re-
                   duced erosion along the mainland and Sandusky Bay reaches by*
                   protecting the base of the shore. The most notable examples
                   of this type of protection are along the Penn Central Railroad
                   to Raccoon Creek reach, where there are stretches where the
                   recession rate was as high as 19 to 21 ft/yr (A m) in the
                   1937 to 1973 period. Unlike the stickout structures, the
                   parallel structures, which consist largely of seawalls, do
                   not appear to have a detrimental effect on the adjacent shore
                   because these structures do not directly affect the longshore
                   transport of sand. However, because the principal source of
                   the beach material is the shore, as it is along the mainland--
                   Lorain-Erie County line to Cedar Point jetty stretch--by
                   protecting the shore the source of beach sediment is largely
                   cut off. In general, in the late period, along stretches
                   where there is a concentration of structures the recession
                   rate is slower than that of the early period, when there were
                   fewer structures.

                   Beaches

                        In stretches along the mainland shore (Lorain-Erie County
                   line to Cedar Point) where there were wide, greater than
                   100 feet (30 m) beaches--for example, the beaches on the up-
                   drift (east side) of the jetties at Huron River and at Cedar
                   Point--the recession rate within a given period was very slow.
                   On the other hand, where there were narrow, less than 50 feet
                   (15 m) beaches in combination with an unprotected shore--as
                   along stretches downdrift of stickout structures between
                   Vermilion and Old Woman Creek--the recession rates were slow
                   to moderate. The lack or scarcity of beaches along the
                   Sandusky Bay reaches and the Kelleys Island reach precludes a
                   discussion of the effect of beaches for these reasons.

                                                 13

              Recession Rates 1877-1937

                   The modal recession rate was between very slow and slow,
              less than I to 1-3 ft/yr (.3-.9 m) and the range in recession
              rates was very slow to moderate between 3-5 ft/yr (.9-1.5 m)
              along the mainland shore, excluding the Sawmill Creek to Cedar
              Point jetty reach; the modal recession rate was rapid, between
              5-7 ft/yr (1.5-2.1 m) and the range in recession rates was very
              slow to 21-23 ft/yr (6.4-7 m) along the Penn Central Railroad
              to Raccoon Creek reach; and the modal recession rate was very
              slow and the range in recession rates was very slow to moderate
              along the Kelleys Island reach. In general, the principal
              factors contributing to the relatively low rates along the
              mainland shore are the manmade structures and gentle nearshore
              slope along the Lorain-Erie County line to Cranberry Creek
              reach and the beaches along the Cranberry Creek to Sawmill
              Creek reach. The high rates along the Penn Central Railroad
              bridge to Raccoon Creek reach as well as the low rates along
              the Kelleys Island reach are largely due to the shore deposits--
              easily weathered and eroded glaciolacustrine clay for the
              Sandusky Bay shore and resistant rock for Kelleys Island.

              Recession Rates 1937-1973

                   The modal recession rate was very slow, less than 1 ft/yr
              (A m) and the range in recession rates was very slow to 9-11
              ft/yr (2.7-3.3 m) along the mainland shore; the modal recession
              rate was very slow and the range in recession rates was very
              slow to between moderate, 3-5 ft/yr (.9-1.5 m) and 15-17 ft/yr
              (4.5-5:1 m) along the two Sandusky Bay reaches; and the modal
              recession rate was very slow and the range in recession rates
              very slow to moderate along the Kelleys Island reach. Overall,
              the principal factors contributing to low recession rates along
              the mainland shore include manmade structures, a gentle near-
              shore slope, and beaches. Manmade structures are the principal
              factor contributing to low rates along the two Sandusky Bay
              reaches, particularly the Cedar Point causeway to Penn Central
              Railroad bridge reach; and the rocky shore is the principal
              factor contributing to the low rates along the Kelleys Island
              reach.

              Recession Rates 1877-1937 to 1937-1973

                   For the four reaches for which there are recession rate
              data for the two periods (Lorain-Erie County line to Cranberry
              Creek, Cranberry Creek to Sawmill Creek, Penn Central Railroad
              bridge to Raccoon Creek, and Kelleys Island) the overriding
              factor contributing to the decrease in the modal recession rate
              for the mainland and the Sandusky Bay reach and the overall
              decrease in the range in recession rates is the presence of
              manmade structures. The increased number of structures, as

                                              14

                   well as the greater length of shore protected by these struc-
                   tures are responsible for the decrease in the modal recession
                   rates as well as the general decrease in the range in
                   recession rates.

                   Present and Future Considerations

                        Corrective measures are being cons  idered for a major
                   problem area, the stretch downdrift of the Huron Harbor jetties.
                   The Buffalo District office of the U.S. Army Corps of Engineers
                   has undertaken a study of the Huron Harbor area, at the request
                   of the Ohio Department of Natural Resources. The Corps is
                   authorized under section III of Public Law 483, U.S. 90th
                   Congress, to investigate, study, and construct projects for
                   the prevention or mitigation of shore damages attributable to
                   Federal navigation works. The cost of installing, operating,
                   and maintaining such projects shall be borne entirely by the
                   United States. No such project shall be constructed without
                   specific authorization by Congress if the estimated first
                   costs exceeds $1,000,000 ... (U.S. Dept. of the Army, 1970,
                   Appendix 1, p. 1-9). It is hoped that within the    next few years
                   a solution can be worked out to reduce the effect of the Huron
                   River jetty complex on the downdrift shore.

                        In addition, another section III study has been undertaken
                   by the Buffalo District office on-a smaller, yet more con-
                   troversial, structure: the jetty-breakwater complex at
                   Vermilion.

                        If one assumes that the shore of Erie and Sandusky
                   Counties will one day be reasonably well protected from storm
                   waves, there will then be another problem--that of beach sand.
                   Because the shore can be shown to account for much of the
                   sand in the longshore drift system (for example, Carter,
                   1975, p.2), if the natural supply is not maintained by reces-
                   sion and the sand in the longshore drift system continues to
                   be transported along the mainland shore to the west to be
                   trapped by the jetties at Huron or Cedar Point, then the
                   beaches will decrease in size, the nearshore slope will in-
                   crease, and the shore will be subjected to greater wave
                   energy. Therefore, if by protecting the shore we lose the
                   source of the sand, but we want beaches and gentle nearshore
                   slopes for shore protection as well as for recreational
                   pursuits, we are going to have to either recycle the sand
                   that we are now trapping, perhaps within cells defined on the
                   downdrift side by major stickout structures, or nourish our
                   beaches with sand from an outside source, presumably off-
                   shore deposits..

                                                 15

                                           LORAIN COUNTY

                  Setting

                       The moderately to densely built-up Lorain County shore
                  fronts 21 miles (33.7 km) of Lake Erie in north-central Ohio
                  between Erie County to the west and Cuyahoga County to the
                  east. Twenty to twenty-five foot (6-7.6 m) high bluffs and
                  slopes make up the shore, with shale exposed in the wave erosion
                  zone to the west in the Vermilion-on-the-Lake area and to the
                  east, east of the Sheffield Lake area. Till, capped in places
                  by glaciolacustrine clay, makes up the shore in the intervening
                  area. Discontinuous sand beaches, commonly less than 50 feet
                  (15.2 m) wide, front the shore; there is also a variety of shore-
                  protection structures, largely groins and seawalls. There are
                  over 765 structures along the shore; most of these structures
                  are located along the more easily eroded till bluffs and slopes
                  of the central portion of the shore.' The most dominant struc-
                  tures are the jetties and breakwaters which surround Lorain
                  Harbor. The nearshore slopes are least offshore of the shale.
                  The water depth 500 feet (152 m) offshore at a lake level
                  elevation of 570.0 feet is about 5 feet (1.5 m) for the areas
                  bordering shale and about 10 feet (3 m) for the areas bordering
                  till. Similarly, for the eastern and western areas bordered
                  by shale, the bottom to 2,000 feet (610 m) offshore consists
                  largely of shale; for the central portion of the shore-bordered
                  by more easily eroded till and glaciolacustrine clay, the
                  bottom is largely till.

                  Shore Processes

                       Storm waves appear to be the principal cause of erosion
                  along the shore of Lorain County. Wave erosion removes in-
                  place and slumped material near lake level, thus maintaining
                  an unstable bluff or slope. Lake level is a major factor in
                  this process. The higher the lake, the closer the waves break
                  to the shore and the greater the wave energy expended on the
                  shore deposits; consequently, the greater the recession rates.

                       Mass wasting follows wave erosion. Falls, slumps, and
                  flows are most common where there are stratigraphic or struc-
                  tural differences such as bedding planes, zones of laminated
                  clay within the till, or joints. Because of the largely
                  cohesive nature of the shore deposits, failure of a bluff,
                  slope or bank may take place days, weeks, or even months after
                  wave erosion.

                  Shoreline Changes

                       The principal change in the Lorain County shore from 1876
                  to 1973 has been the increase in unevenness of the shore. For

                                               17

               the most part the increase is slight along the irregular shale
               shore fronting the western and eastern portions of the shore
               and greatest along the intensely developed, more easily eroded
               central portion of the shore. The change in shape for the most
               part can be related directly to manmade structures. These
               structures are also largely responsible for the changes in
               beach size and distribution.

               Structures

                   In 1876 waves impinged upon a largely natural Lorain County
               shore. Wave erosion and subsequent mass wasting of the unpro-
               tected shore, particularly between Vermilion-on-the-Lake and
               Avon Lake, provided sand and gravel to form a nearly continuous
               ribbon of coarse-grained sediment along the shore in the beach
               and shoreline and nearshore zones. Wave erosion and mass
               wasting are continuing today, but, because of the manmade
               structures that have been built along the shore, the effect of
               the waves has been altered. The structures, largely by dis-
               rupting the longshore drift of sand and/or by armoring the
               shore, have caused a decrease in the recession rates along
               some stretches and at the same time have caused an increase in
               the recession rates along other stretches.

                   Stickout structures--largely groins and jetties--by
               modifying the longshore drift of sand, have had the greatest
               influence on shoreline changes and recession rates. Entrapment
               of sand on the updrift side of a structure results in a wider
               beach'and a gentler nearshore slope. The increase in beach
               width and decrease in the nearshore slope on the updrift side
               reduce the amount of wave energy impinging upon the shore and
               cause a decrease*in the recession rate. On the downdrift side
               the decrease in beach width and increase in nearshore slope
               increase the amount of wave energy impinging upon the shore,
               causing an increase in the recession rate.

                   Parallel structures--seawalls and breakwaters--have reduced
               erosion by protecting the base of the shore. Unlike the stickout
               structures, the parallel structures, which consist largely of
               seawalls, do not appear to have a detrimental effect on the
               adjacent shore because these structures do not directly affect
               the longshore transport of sand. However, because the principal
               source of the beach material is the shore, then by protecting
               the shore the source of beach sediment is largely cut off.
               Lastly, in general, along stretches in the late period where
               there is a concentration of structures the recession rate is
               slower than that of the early period, when there were fewer
               structures.

                                                18

                   Beaches

                       Along the few  stretches where there were wide, greater
                   than 100 feet (30 m) beaches, for example the beach west of
                   the Lorain Harbor structures, the recession rates are very
                   slow or slow. On  the other hand, where there were narrow, less
                   than 50 feet (15 m) beaches in combination with a largely
                   unprotected till shore--as along the stretches on either side
                   of the Elyria Waterworks--the recession rates are slow or
                   moderate.

                   Recession Rates 1876-1937

                       The modal recession rate was very slow, less than 1 ft/yr
                   (.3 m) and the range in recession rates was very show to
                   moderate 3-5 ft/yr (.9-1.5 m) within this period. In general,
                   the main factors contributing to the low recession rates are
                   rock along the western and eastern portions of the shore and
                   the combination of beaches and manmade structures along the
                   central portion of the shore. For the most part, the stretches
                   which receded at a moderate rate were located in the Lorain
                   area and were fronted by narrow beaches or lacked adequate
                   structural protection.

                   Recession Rates 1937-1973

                       The modal recession rate and the range in recession rates
                   were the same as in the 1876-1937 period, very slow, less than
                   1 ft/yr (.3 m) and very slow to moderate, 3-5 ft/yr (.9-1.5 m).
                   The same factors--rock shore, manmade structures, and/or
                   beaches--contributed to the low recession rates in this period.

                   Recession Rates 1376-1937 to 1937-1973

                       Even though the mode and range in recession rates were
                   the same in both periods there was about a 97 percent reduction
                   in the length of shore receding at the moderate rate and a 56
                   percent reduction in the length of shore receding at the slow
                   rate in the 1937-1073 period. The increased number of struc-
                   tures as well as the greater length of shore protected by
                   these structures is probably the reason for the overall de-
                   crease within the recession rate classes. On the other hand,
                   the stretches showing an increase in recession rates (very slow
                   to slow) are for the most part unprotected and downdrift of
                   stickout structures.

                                                19

                   Corrective measures are being undertaken to protect
              Lakeview Park from shore erosion.  The 2.5 million dollar
              project to be financed by the Ohio Department of Natural
              Resources, the U.S. Army Corps of Engineers, and the City of
              Lorain began in 1977. The project will protect the shore as
              well as provide a large sand beach.

                                              20

                                           CUYAHOGA COUNTY

                   Setting

                        The densely built-up Cuyahoga County shore lies along
                   Lake Erie in northeastern Ohio between Lorain County to the
                   west and Lake County to the east. Fifty to sixty foot high
                   (15-18 m) bluffs and slopes made up largely of shale charac-
                   terize the western shore; manmade structures consisting
                   largely of seawalls and breakwaters characterize the central
                   portion of the shore--which fronts downtown Cleveland, and
                   25 foot (7.6 m) bluffs and slopes made up largely of till
                   characterize the eastern shore. Discontinuous sand beaches,
                   commonly 50 to 100 feet (15-30 m) wide, front the shore, along
                   with a 'variety of shore-protection structures. There are many
                   structures along the shore; most of these structures are
                   located along the more easily eroded till of the eastern shore.
                   The most dominant structure is the Cleveland breakwater, which
                   protects about 5 miles of the Cleveland shore from surface
                   waves. The nearshore slopes are comparable along the western
                   and eastern shores. From the western edge of the county to
                   Edgewater Park the bottom to 2,000 feet (610 m) offshore is
                   made up of shale or sand; behind the breakwater the bottom is
                   mud; east of the breakwater to the county line the bottom is
                   largely sand, with,shale exposed in the Euclid area. For the
                   most part the sand is thin and rarely has a thickness of more
                   than a few feet.

                   Shore Processes

                        Storm waves appear to be the principal cause of erosion
                   along the shore of Cuyahoga County. Wave erosion removes
                   inplace and slumped material near lake level, thus maintaining
                   an unstable bluff or slope. Lake level is a major factor in
                   this process. The higher the lake, the closer the waves break
                   to the shore and the greater the wave energy expended on the
                   shore deposits; consequently, the greater the recession rates.

                        Mass wasting follows wave erosion. Falls, slumps, and
                   flows are most common where there are stratigraphic or struc-
                   tural differences such as bedding planes, zones of laminated
                   clay within the till, or joints. Because of the largely
                   cohesive nature of the shore deposits, failure of a bluff,
                   slope, or bank may take place days, weeks, or even months after
                   wave erosion.

                   Shoreline Changes

                        The principal change in the Cuyahoga County shore from
                   1876 to 1973 has been the increase in unevenness of the shore.
                   For the most part, the increase is slight along the western

                                                21

              and eastern reaches and marked behind the Cleveland breakwater,
              where there has been extensive manmade modification (fill).
              The change in shape for the most part can be related directly
              to manmade structures. These structures are also largely res-
              ponsible for the changes in beach size and distribution.

              Structures

                   In 1876, waves impinged upon a largely natural Cuyahoga
              County shore. Wave erosion and subsequent mass wasting of the
              unprotected shore, particularly east of the Cuyahoga River,
              provided sand and gravel to form a nearly continuous ribbon
              of coarse-grained sediment along the shore in the beach and
              shoreline and nearshore zones. Wave erosion and mass wasting
              are continuing today, but, because of the manmade structures
              that have been built along the shore, the effect of the waves
              has been altered. The structures, largely by disrupting the
              longshore drift of sand and/or by armoring t@e shore, have
              caused a decrease in the recession rates along some stretches
              and at the same time have caused an increase in the recession
              rates along other stretches.

                   Stickout structures--largely groins and jetties--by
              modifying the longshore drift of sand, have had the greatest
              influence on shoreline changes and recession rates. Entrap-
              ment of sand on the updrift side of a structure results in a
              wider beach and a gentler nearshore slope. The increase in
              beach width and decrease in the nearshore slope on the updrift
              side reduce the amount of wave energy impinging upon the shore
              and cause a decrease in the recession rate; on the downdrift
              side the decrease in beach width and increase in nearshore
              slope increase the amount of wave energy impinging upon the
              shore, causing an increase in the recession rate.

                   Parallel structures--seawalls and breakwaters--have re-
              duced erosion by protecting the base of the shore. Unlike
              the stickout structures, the parallel structures, which con-
              sist largely of seawalls, do not appear to have a detrimental
              effect on the adjacent shore because these structures do not
              directly affect the longshore transport of sand. However,
              because the principal source of the-beach material is the
              shore, by protecting the shore the source of beach sediment
              is largely cut off. In general, in the late period along
              stretches where there is a concentration of structures, the
              recession rate is slower than that in the early period, when
              there were fewer structures.

              Beaches

                   Along the few stretches where there were wide, greater
              than 100 feet (30 m) beaches, for example the beach on the

                                               22

                   updrift (west side) of the jetty at Euclid Creek--the recession
                   rate within a given period was very slow. On the other hand,
                   where there were narrow, less than 50 feet (15 m), beaches in
                   combination with a largely unprotected shore--as along the
                   stretch downdrift of the jetty at Euclid Creek--the recession
                   rate was slow.

                   Recession Rates 1876-1937

                        The moda 1 recession rate was very slow, less than I ft/yr
                   (.3 m) and the range in recession rates was very slow to slow,
                   1-3 ft/yr (A-A m) within this period. In general, the main
                   factors contributing to the low recession rates are the rock
                   shore along western Cuyahoga County and combinations of
                   beaches, manmade structures, or rock shore along eastern
                   Cuyahoga County.

                   Recession Rates 1937-1973

                       The modal recession rate and the range in recession rates
                   were the same as in the 1876-1937 period, very slow, less than
                   1 ft/yr (.3 m), and very slow to slow, 1-3 ft/yr (A-A M).
                   The same factors7-rock shore, manmade structures, and/or
                   beaches--contributed to the low recession rates in this period.

                   Recession Rates 1876-1937 to 1937-1973

                        Even though the mode and range in recession rates were
                   the same 'in both periods there was about an 80 percent re-
                   duction in the@length of shore receding at the slow rate in
                   the 1937-1973 period. The increased number of structures as
                   well as the greater length of shore protected by these
                   structures is probably the reason@for the overall decrease
                   within the recession rate class of slow. On the other hand,
                   the stretches showing an increase in recession rates (very
                   slow to slow) are for the most part unprotected and downdrift
                   of stickout structures.

                                                 23

                                             LAKECOUNTY

                   Setting

                        Lake County, one of eight Ohio counties  that border the
                   southern shore of Lake Erie, lies along the eastern part of
                   the Ohio shore and is bordered on the lake by Ashtabula County
                   to the east and Cuyahoga County to the west. The shoreline
                   length of Lake County is about 30 miles (48 km).

                        The shore can be divided into two geographic areas, which
                   are separated by the Grand River. The shore west of the river
                   is for the most part urban and built up, whereas the shore
                   east of the river is more sparsely settled and there is some
                   agricultural and forest land. The more densely populated
                   centers include Willowick, Eastlake, 'Mentor-on-thelLake,
                   Mentor Headlands, Fairport Harbor, and Madison-on-the-Lake.

                        The shore is made up of 30 to 40 foot (9-12 m) high
                   bluffs and slopes composed of till overlain by glaciolacust-
                   rine deposits. Lakeward of the shore are narrow sand beaches
                   (generally several tens of feet wide) and gentle nearshore
                   slopes [about one degree within 500 feet (152 m) of the shore-
                   line]. Along this shore erosion is the crucial Drocess.
                   Erosion of in-place or slumped material by storm--generated
                   surface waves reduces the resisting moment at the base of the
                   bluff or slope, leading to and perpetuating shore recession.

                        The Lake County shore has a flat, glaciated appearance
                   that is interrupted here and there by small hills or stream
                   valleys. From the Cuyahoga-Lake County line to Redbird this
                   appearance changes abruptly at the shoreline, where 30 to 40
                   foot (9-12 m) bluffs and/or irregular hammocky slopes com-
                   monly mark the interface between the land and the lake. At
                   Redbird and east to the Lake-Ashtabula County line and land-
                   scape is much less precipitous, and banks and gentle slopes
                   less than 15 feet (5 m) high are common.

                        Aside from the shore-lake interface, the most noticeable
                   topographic breaks are the river valleys. Both the Chagrin
                   and Grand Rivers have cut wide, deep c@annels into the sur-
                   ficial depostis; the Mentor Harbor-Mentor Marsh depression
                   is an abandoned Grand River channel. East of Fairport Harbor,
                   the valley of Chapel Creek in Madison Township is the most
                   noticeable topographic break.

                        There are four principal deposits that make up the Lake
                   County shore: shale (the bedrock), till, glaciolacustrine
                   clay, the glaciolacustrine sand. These denosits are best
                   exposed along the lakeshore bluffs, although exposures can
                   be found in and along the stream channels.

                                                25

                    Shale underlies the entire Lake County study area. The
               shale contains thin resistant siltstone beds and has a northeast
               strike and a gentle southeast dip.

                    Along the entire county shoreline the bottom surface to
               about 2,000 feet (610 m) offshore has a slope of less than one
               degree. However, the slope is not cons  'tant; in general the
               slope decreases. from the western border to the eastern border
               of the county. For example, the mean water depth 2,000 feet
               (610 m) from the shoreline west of Grand River was 24 feet (7 m),
               with a range of 14.5 to 30 feet (4-9 m), whereas the mean water
               depth 2,000 feet (610 m) from the shoreline east of Grand River
               was 21 feet (6 m), with a range of 17 to 24 feet (5-7 m).
               Within 500 feet (152 m) of the shoreline--in the zone where most
               of the wave energy is expended on the bottom--the mean water
               depth is less than 13 feet (4 m). At 500 feet (152 m) the
               depth of the water decreases from about 13 feet (4 m) along the
               westen=st reach to about 9 feet (3 m) along the easternmost
               reach. Structures have influenced the slope in places. The
               natural slope west of Grand River has been reduced because of
               sand accumulation on the windward side of the west Jetty at
               Grand River. Just to the east of the Grand River a scarcity
               of sand has contributed to a steeper slope.

                    Sand beaches, which differ greatly in size, form a dis-
               continuous ribbon along nearly the entire Lake County shoreline.
               The longest continuous stretA of moderate-to-large (greater
               than 50 feet (15 m) wide) beaches is from North Perry Park to
               the Lake-Ashtabula County line. Other sizeable beaches are
               present on the windward (west) side of the jetties at Chagrin
               River, Mentor Harbor, and Grand River.

                    The beaches are composed of medium-to very coarse grained,
               subangular to subrounded, well-sorted sand composed largely of
               rock fragments and quartz. The beaches from the Cuyahoga-Lake
               County line to Grand River have an average thickness of about
               5 feet (1.5 m), whereas the beaches east of Grand River to the
               Lake-Ashtabula County line have an average thickness of about
               3 feet (I m). Most of the beaches west of Grand River lie on
               till; the beaches east of Grand River lie on shale.

                    Manmade structur'es as well as sand beaches are a signi-
               ficant part of the Lake County shoreline. Almost without
               exception such structures have a direct effect on the physical
               proc esses operating along the shoreline. The structures can
               be divided into four basic types: breakwaters, jetties, groins,
               and seawalls. Included in the 402 structures are 26 break-
               waters, 13 jetties, 200 groins, 46 groin fields, and 81
               seawalls. The structures range in size from a few feet wide
               and several feet long to several feet wide and several hundred
               feet long. Groins and seawalls are distributed along the entire
               shoreline, whereas breakwaters and jetties are located primarily
               at the mouths of rivers and harbors. The number of structures

                                                26

                   is directly proportional to land development. The 195
                   structures located west of Grand River are fairly evenly dis-
                   tributed along the built-up shoreline. Along the sparselv
                   populated shore between Grand River and the Redbird area and
                   the Lake-Ashtabula County line, a much more built-up shoreline
                   only about half the length of the Grand River to Redbird shore-
                   line, there are 128 structures.

                   Shore Processes

                        Shore erosion can be related to many processes, but along
                   the Lake County shore, there are two principal shore erosion
                   processes: wave erosion and mass wasting. Of the two pro-
                   cesses, wave erosion is by far the more significant. These
                   processes erode the shore at different rates because of two
                   primary factors: the physical setting and the weather.
                   Variation in recession rates among different reaches along
                   the shore and through time generally can be related to these
                   two factors. Along the shore of Lake,County the principal mass-
                   wasting processes are block falls, rotational slumps, debris
                   flows, and piping.

                        Block falls are common along the high till bluffs east of
                   Painesville-on-the-Lake; rotational slumps are common along
                   most of the Lake County shore, especially between Mentor
                   Harbor and Camp Roosevelt. Debris flows are common in the
                   thick clays east of Camp Roosevelt; and piping is common in
                   the thick sands of Camp Roosevelt.

                   Shoreline Changes

                        The best approximation for a natural (pre-structure)
                   recession rate is the rate during the 1876-1937 period; the
                   modal recession rate in this period was slow. In the 1937-
                   1973 period the modal rate was very slow, although there was
                   a sizeable length (15 percent) of the reach that receded at
                   a moderate rate. The greater variability in the recession
                   rates in the 1937-1973 period than in the 1876-1937 period
                   resulted from the manmade structures. Seawalls and similar
                   structures help protect the shore immediately landward of
                   the structures. Groins and similar stickout structures, by
                   trapping sand on the updrift side, reduce the nearshore slope
                   and widen the beach to help protect the updrift shore. At
                   the same time, however, these types of structures deprive the
                   downdrift shore of sand, increase the nearshore slope, narrow
                   the beach, and thus contribute to accelerated recession rates
                   downdrift. This is particulary true along structurally
                   unprotected areas immediately downdrift of substantial
                   structures. Further evidence of this influence can be seen
                   in the more irregular shoreline shape in the 1937-1973   period
                   especially in areas protected by stickout structures adjacent

                                                27

              to unprotected areas. Overall, the recession rates have
              been reduced by these structures from slow to very slow in some
              areas and have been increased from slow to moderate in other areas.

                   Study of maps and aerial photographs of Lake County shows
              major shoreline changes between 1976 and 1973. In 1876 the Lake
              County shoreline had a fairly even outline and was fronted by a
              continuous beach and several manmade structures. In 1973 the
              shore had an uneven outline and was fronted by discontinuous
              beaches and about 400 manmade structures. These changes in out-
              line, beaches, and manmade structures are reflected in recession
              rates, determined from a 1:4,800 recession-line map of the
              entire county shore. The principal rate of recession decreased
              from slow, 1-3 ft/yr (.3-.9 m), in the 1876-1937 period to very
              slow, less than 1 ft/yr (.3 m), in the 1937-1973 period.
              However, the range of recession rates increased from very slow
              to moderate 3-5 ft/yr (.9-1.5 m) to very slow to very rapid
              7-9 ft/yr (2.2.7 m).

                   Manmade structures are the principal cause of these
              changes in recession rates. The increased number of struc-
              tures has helped protect the shore from wave erosion by
              trapping sand (groins) or by directly armoring the shore
              (seawalls). On the other hand, the few large jetties and
              large groins, by significantly disrupting the longshore drift,
              have caused a downdrift increase in nearshore slope and a
              decrease in beach width, leading to accelerated wave erosion
              of the shore downdrift of these structures.

                   The longshore drift is primarily from southwest to north-
              east. Reversals in longshore drift to take place from time to
              time, especially during the northeast storms, but, because of
              the shoreline orientation and the greater fetch for onshore
              winds from the west, the overall result is a net drift to the
              northeast. Evidence for this west-to-east movement is seen
              most readily on the windward (west) side of large structures
              such as the intake jetties at Chagrin River, the Mentor Harbor
              jetties, and the Grand River jetties, where large amounts of
              sand have been trapped by the structures.

                   Because of the somewhat northerly orientation of the
              shore from the Cuyahoga-Lake County line to Grand River, the
              longshore drift along this part of the shore is probably
              more unidirectional than it is from Grand River to the Lake-
              Ashtabula County line, where the shore has a more easterly
              orientation and is less sheltered from easterly winds.

              Recession Rates 1876-1937

                   The recession,rates were quite consistent in this period.
              A slow, 1-3 ft/yr (.13-.9 m), rate was exceeded only in a
              650-ft (198 m) stretch that had a moderate (3-5 ft/yr)

                                               28

                 recession rate. This stretch receding at a moderate rate was
                 unprotected by structures in 1937; however, there were stickout
                 structures on either side of the stretch.

                 Recession Rates 1937-1973

                      The recession rates in this period were mainly verv slow,
                 less than 1 ft/yr (A m) and slow, although two stretches with
                 a combined length of over one-half mile (over 800 m), receded
                 at a moderate rate. Both of these stretches were structurally
                 unprotected and lay adjacent to and east of substantial stick-
                 out structures.' In general, areas that have a high structure
                 density have lower recession rates than areas with a low
                 structure density.

                                                29

                                        ASHTABULA COUNTY

                  Setting

                       The sparsely to moderately bu ilt-up Ashtabula County shore
                  lies along Lake Erie in northeastern Ohio between Lake County
                  to the west and Pennsylvania to the east. The shore deposits,
                  which are composed largely of till, make up the banks, bluffs,
                  and slopes, which increase in elevation from about 15 feet (5 m)
                  along the western edge of the county to about 65 feet (20 m)
                  along the eastern half of the countV. Discontinuous sand
                  beaches, commonly 50 to 100 feet (15 to 30 m) wide, front the
                  shore. There are a variety of shore-protection structures
                  along the shore as well as two major jetty complexes which ex-
                  tend out into the lake for several hundred feet (a few hundred
                  meters). The nearshore slope is gentle and fairly constant
                  along the entire county. The average water depth 500 feet
                  (152 m) offshore at a lake-level elevation of 570.0 feet is
                  about 6 feet (2 m). The nearshore bottom within 2,000 feet
                  (610 m) of shore consists of a narrow (a few to several hundred
                  feet wide) band of sand adjacent to the shore and shale farther
                  offshore. The sand for the most part is no more than 3 feet
                  (1 m) thick.

                  Shore Processes
                       Storm waves appear to be the p@incipal  cause of erosion
                  along the shore.of Ashtabula County. Wave erosion removes in-
                  place and slumped material near lake level, thus maintaining an
                  unstable bluff or slope. Lake level is a major factor in this
                  process. The higher the lake, the closer the waves break to
                  the shore and the greater the wave energy expended on the
                  shore deposits. Consequently, high lake levels cause greater
                  recession rates.

                       Mass wasting follows wave erosion. Falls, slumps, and
                  flows are most common where there are stratigraphic or struc-
                  tural differences such as bedding planes, zones of laminated
                  clay within the till, or joints. Because of the largely
                  cohesive nature of the shore deposits, failure of a bluff,
                  slope, or bank may take place days, weeks, or even months after
                  wave erosion.

                  Shoreline Changes

                       The principal change in the Ashtabula County shore from
                  1876 to 1973 has been the increase in unevenness of the shore.
                  The 1876 shore, with the exception of the Ashtabula and
                  Conneaut areas, had a fairly even, uniform shape, whereas the
                  1973 shore has a much more uneven, nonuniform shape. The
                  change in shape can be related directly to manmad.e structures.

                                                 31

              These structures are also largely responsible for the changes in
              beach size and distribution.

              Structures

                   In 1876 waves impinged upon a largely natural Ashtabula
              County shore. Wave erosion and subsequent' mass wasting of the
              unprotected shore provided sand and gravel to form a nearly con-
              tinuous ribbon of coarse-grained sedimenIt along the shore in
              the beach, shoreline and nearshore zones. Wave erosion and mass
              wasting are continuing today, but, because of the manmade
              structures that have been built along the shore, the effect of
              the waves has been altered. The structures, largely by disrupt-
              ing the longshore drift of sand and/or by armoring the shore,
              have caused a decrease in the recession rates along some stretches
              and at the same time have caused an increase in the recession
              rates along other stretches.

                   Stickout structures--largely groins,and jetties--bv modify-
              ing the longshore drift of sand! have had the greatest influence
              on shoreline changes and recession rates. Entrapment of sand on
              the updrift side of a structure results in a wider beach and a
              gentler nearshore slope. The increase in beach width and de-
              crease in the nearshore slope on the updrift side reduce the
              amount of wave energy impinging upon the shore and cause a
              decrease in the recession rate; on the downdrift side the de-
              crease in beach width and increase in nearshore slope increase
              the amount of wave energy impinging upon the shore, causing an
              increase in the recession rate.

                   Parallel structures--seawalls and breakwaters--have reduced
              erosion bV protecting the base of the shore. Unlike the stick-
              out structures, the parallel structures, which consist largely
              of seawalls, do not appear to have a detrimental effect on the
              adjacent shore because these structures do not directly affect
              the longshore transport of sand. However, because the principal
              source of the beach material is the shore, by protecting the
              shore the source of beach sediment is largely cut off. In
              general, in more recent time, along stretches where there is a
              concentration of structures, the recession rate is slower than
              that in the earlier period, when there are fewer structures.

              Beaches

                   In stretches where there were wide beaches, greater than
              100 feet (30 m), for example the beaches on the updrift (west
              side) of the jetties at the Ashtabula River and at Conneaut
              Creek, the recession rate within a given period'was very slow.
              On the other hand, where there were narrow beaches, less than
              50 feet (15 m), in combination with an unprotected shore--as
              along stretches downdrift of stickout structures between

                                               32

                  Geneva-on-the-Lake and Ashtabula--the recession rates were slow
                  to moderate.

                  Recession Rates 1876-1938

                       The modal recession rate was very slow, less than   1 ft/yr
                  (.3 m), and the range in recession rates was very slow   to
                  moderate, 3-5 ft/yr (.9-1.5 m) within this period. In    general,
                  the main factors contributing to the low recession rates are
                  the gentle nearshore slopes and the beaches. The gentle near-
                  shore slopes have helped to protect the shore along the entire
                  county, as have the beaches except for the reach directly
                  downdrift of the Ashtabula jetties. This reach, the Ashtabula
                  River to Whitman Creek reach, is the only one to have moderate
                  recession rates. The structures, in trapping sand from the
                  west-to-east longshore drift, have deprived the downdrift reach
                  of sand, thereby reducing the beach width and contributing to
                  the relatively high recession rates.

                  Recession Rates 1938-1973

                       The modal recession rate was very slow, less than I ft/yr
                  (.3 m), and the range in recession rates was very slow to rapid,
                  5-7 ft/yr (1.5-2.1 m) within this period. As in the 1876-1938
                  period, the main factors contributing to the overall low
                  recession rates are the gentle nearshore slopes and the beaches.
                  The stretches receding at moderate and rapid rates are located
                  downdrift of structures which lie between the Lake-Ashtabula
                  County line and Red Brook.

                  Recession Rates 1876-1938 to 1938-1973

                       The overall, but slight, reduction within the recession
                  rate classes from the 1876-1938 period to the 1938-1973
                  period can most likelylbe related to the manmade structures.
                  The increased number of structures, as well as the greater
                  length of shore protected by these structures, is probably
                  the reason for the decrease within the recession rate classes,
                  whereas the stretches showing an increase in recession rates
                  are unprotected and for the most part downdrift of stickout
                  structures.

                                                 33

                               POTENTIAL PROTECTION CONSIDERATIONS

                      The recession rates along the entire shore of Lake Erie
                  vary from one location to another. Areas with shore lengths
                  up to a few hundred feet, (less than 100 m) can probably be
                  most easily protected by manmade structures, particularly if
                  the stretch is between protected areas. The type of protection
                  naturally will depend on the physical setting. Stretches
                  with shore lengths up to several hundred feet (greater than
                  100 m) can be protected by either a nonstructural method such
                  as increasing the supply of sand along the stretch (beach
                  nourishment) or a coi6ination nonstructural and structural
                  method such as increasing the supply of sand as well as build-
                  ing structures to retain it.

                      The shore accounts for much of the sand in the longshore
                  drift system. If the natural supply is not maintained by
                  recession and the sand in the longshore drift system continues
                  to be transported along the mainland shore then the beaches
                  will be sublected to greater wave energy. Therefore, by
                  protecting the shore we lose the source of the sand, but
                  because we want beaches and gentle nearshore slopes for shore
                  protection as well as for recreational pursuits, we are going
                  to have to either recycle the sand that we are now trapping,
                  perhaps within cells defined on the downdrift side by major
                  stickout structures, or nourish our beaches with sand from an
                  outside source, presumably offshore deposits.

                     Last but not least, in any consideration of solutions for
                  shore protection is lake-level regulation. A decrease in the
                  level of the lake would reduce the amount of wave energy ,
                  reaching the shore; the greater the decrease in lake level,
                  the greater the decrease in wave energy reaching the shore.
                  Perhaps in the distant future, if shoreland becomes expensive
                  enough and lake sedimentation becomes,a tangible problem, this
                  solution will become feasible enough to help protect the entire
                  Lake Erie shore.

                                                35

                                             FLOODING

                  Introduction

                      No geographic area in Ohio is more inherently ripe for con-
                  flict than where the land and water meet. This is expecially
                  true in regard to the threat of flooding. The flooding problem
                  along the Lake Erie shoreline is especially hazardous since
                  it is plagued by floods resulting from riverine and lake
                  sources including the critical area where these two forces
                  collide. The damage suffered in the coastal area in the past
                  and the continual threat of flooding in the future make this an
                  issue-of vital concern in Ohio's Coastal Zone Management Program.

                  Geological History

                      Four major phases of glaciation have formed the relief and
                  drainage pattern of,the Great Lakes Basin. The sediments that
                  overlay the bedrock consist of glacial drift deposited by the
                  continental ice sheets, streams created by the melting ice,
                  stratified beds laid down in ancient glacial lakes, and sand
                  consisting of materials picked up and redeposited by the wind.
                  These unconsolidated, readily erodible sediments have been
                  partially reworked by post-glacial streams and deposited as
                  alluvium in the Great Lakes and their flood plains.

                      There is also a slow geological tilting of the earth's
                  surface around Lake 'Erie. The southwest part of the basin is
                  being lowered at the rate of about'one foot per century. It
                  is believed that this is a consequence of the "springing back"
                  of the earth's surface at the northeast end of the basin after
                  the last glacier retreated.

                  Natural Attraction

                      Geographic location is the key in the history of Ohio's
                  shoreline development. From the first fLir traders and settlers
                  to the current thousands of businesses and residents in the
                  coastal area it was the attractiveness of the lake and its
                  estuaries that has influenced dev6lopment patterns and loca-
                  tion. The advantage of large quanticies of water for
                  transportation, power, industry, human consumption,. and
                  recreation was evident from the ba-ginning.

                      Although the advantages of such locations for many of these
                  needs has faded with modern '@-echnology, the desire to locate
                  along the lake still influences development patterns in the
                  coastal area. Today, the aesthetic aspect is one of the most
                  influential attraction factors in lake-shore location.

                                                37

                   Unfortunately the lack of understanding or adequate con-
              sideration of the natural forces associated with shoreline
              locations has created a critical flood hazard for a considerable
              portion of the region's coastal develoDment. This lack of con-
              sideration must be corrected in future development plans so that
              succeeding generations are not plagued by the problem and
              financial burden of flood-prone development. The consideration
              .of flood-prone areas and the adoption of regulatory controls on
              development in these areas is'referred to as flood plain
              management. A review of the natural flooding processes will
              give us a better appreciation of the need for flood plain
              management.

              Riverine Flooding

                   Flooding may occur at any time, but throughout the Lake
              Erie region most major floods have occurred during late winter
              or early spring.   Rainfalls combined with snowmelt on frozen
              or nearly saturated ground during these seasons produce Deak
              runoff conditions and have created very destructive floo@s.
              The problem is often aggravated by ice jams in the bends of
              stream channels and at the mouths of the streams emptying into
              the lake. The problem is complicated further when the lake is
              frozen. Flood waters can not  get out into the lake during these
              conditions and they are "backed up" in the stream channel in-
              creasing flood heights upstream. Severe thunderstorms during
              the summer months have also produced destructive floods,
              although damage is usually confined to local tributary areas.

                   Rapid urbanization has contributed another aspect to the
              flooding problem. Intensified storm runoff in metropolitan
              areas overloads existing drainage systems which have not kept
              pace with the rate of growth. This creates higher flood levels
              in existing flood-prone areas, sewer backup conditions, and new
              flood-prone areas due to the increased flood levels. Many of
              these flood problems have been aggravated by the loss of flood
              storage and carrying capacity in the flood plains due to con-
              tinued development and filling in these areas. This causes
              even higher flood levels.

                   The flood plain of a river or stream is the area of a
              river channel and the adjacent land, built up by sediments of
              the present stream regime, which is covered with water during
              maximum flood stages. Since the maximum flood stage can never
              be technically known, common practice is to refer to a flood
              plain of a particular frequency of occurrence or magnitude.
              For example the 100 year flood plain (the standard for state
              and federal government programs) is the area flooded by the
              stage associated with a hundred year frequency flood. A hun-
              dred year frequency flood is a flood which has a one percent
              chance of being exceeded in any year. Although calculation of

                                               38

                  possible recurrence is often based upon historical records,
                  there is no guarantee that a 100 year flood will occur with a
                  100 year period or that it will not recur several times during
                  that period.

                      A riverine flood plain (Figure 1) can be divided into two
                  zones or areas for regulatory purposes--the floodway and the
                  flood fringe (also called floodway fringe). The floodway is the
                  portion consisting of the stream channel and overbank areas
                  necessary to convey the flood discharge without increasing flood
                  heights and velocities above adopted levels. The floodway is
                  usually not limited to the actual stream channel. Rather it is'
                  the area calculated to be of sufficient width and flood con-
                  veyance characteristics to pass the flood waters along a reach
                  of stream without increasing flood heights more than the stated
                  level (one foot, one-half foot, etc.) or substantially increas-
                  ing velocities over what they would have been without the
                  assumed confinement. In this calculation the floodway itself
                  is assumed to remain in an open condition (or condition at time
                  of calculation). Floodway areas are subject to frequent, high
                  velocity flooding, often at considerable depths.

                      The flood fringe area is the portion of the regulatory
                  flood plain beyond the limits of the floodway. It is subject
                  to less frequent, lower velocity flooding and does not play a
                  major role in passing flood flows; however, it does provide
                  storage area during the flooding event.

                      With flood plain regulation, development is tightly con-
                  trolled in the floodway to preserve flood flow capacities and
                  protect public safety. In the flood fringe areas most land
                  uses are permitted, provided they are individually protected to
                  a level above the regulatory flood. Unless local flood plain
                  regulation programs are adopted and enforced, flooding problems
                  will continue to compound an already hazardous condition and
                  create a financially unacceptable public burden.

                  Lake Flooding

                      Flooding along Lake Erie occurs when conditions in or on
                  the lake cause water levels to rise above normal. The level of
                  Lake Erie is the result of an integration of the hydraulic
                  characteristics of the connecting channels of the other Great
                  Lakes and the St. Lawrence River and the total water supplies
                  received (Figure 2). The total water supplies are the inflows
                  from Lake Huron, plus the runoff from the land in the Lake Erie
                  Basin, plus the preci-'Pitation falling directly on the lake, less
                  the evaporation from the lake. Figure 3 shows the numbers for
                  these water supply factors for an average ten-year period which
                  includes both high and normal supplies.

                                                39

                     The level of Lake Erie depends on the balance between the
               total water supplies received and its discharge to Lake Ontario.
               If supplies received are greater than those discharged the lake
               level gradually rises. Conversely, if the discharge is greater
               than supplies received the lake level slowly drops. These
               hydrologic factors are the dominant cause of the protracted
               fluctuations in the levels of Lake Erie.

                     Precipitation in the form of rain and snow is the-source
               of all water supplies to the Great Lakes. The low lake levels
               during the mid-1930's and 1960's were the result of abnormally
               low precipitation, while the high lake levels of the early
               1950's an@ 1970's were caused by excessive precipitation. The
               annual precipitation in the Lake Erie Basin has varied from
               24.5 to 42.6 inches. The peak runoff usually occurs in
               March; however, high runoffs also occur during the fall and
               winter as a result of rainfall and snowmelt when land evapora-
               tion and transpiration is least and the ground is either
               saturated or frozen. Such was the case in 1972 with the high
               water levels.

                     The higher levels in the spring and early summer and
               gradual lowering of levels the remainder of the year reflect
               the variations of runoff and evaporation in the Lake Erie
               Basin. In any given year the variations from winter lows to
               summer highs are small, usually averaging about one and one-
               half foot.

                     These natural phenomena are the dominant causes of the
               long-term fluctuations of the Great Lakes. The mean monthly
               levels for Lake Erie since 1860 are shown in Figure 4. The
               magnitude and duration of these fluctuations are irregular
               and for this reason high and low water levels do not occur in
               any regular cycles.

                     The most dramatic changes in water levels are the short-
               term fluctuations caused by strong winds and by sharp
               differentials in barometric pressure. They usually are of
               short duration, lasting less than one da    'v, and do not repre-
               sent any changes in the volume of water in the lake.

                     The winds are caused by the passage of weather systems.
               The strong winds which cause most of the shoreline damage
               occur primarily in the spring and fall. Winds keep the water
               surface of the lake in constant motion and influenc-e the
               littoral currents which build and destroy the beaches.

                     During periods of strong winds, deep water waves generated
               by the wind can reach a height in excess of 25 feet from trough
               to crest. It is the energy released by these waves as they
               break on the shore that causes erosio   .n. When superimposed on
               high water levels, the damage caused by waves is incr      eased.
               This is illustrated in Figure 5. Strong winds tend to build

                                                 40

                 up the level at the downwind shore and reduce the water.level
                 along the upwind shore. Sustained high winds along the
                 southwesterly axis of Lake Erie have caused differences  in the
                 water levels between Buffalo and Toledo of up to 13 feet.
                 Movement of weather systems can produce local changes in
                 atmospheric pressures which in turn cause sudden changes in
                 water levels.

                      In summary, the principal cause of long-term water level
                 fluctuations on Lake Erie is extended periods of excessive or
                 deficient precipitation. The regular annual fluctuations in
                 levels are due to seasonal variation in water supplies. The
                 .short-term fluctuations are the result of wind and meteoro-
                 logical disturbances. When the high seasonal or annual
                 variations accompany high long-term fluctuations the effects
                 are exaggerated and flooding can be quite severe.

                      Since coastal flood conditions differ from riverine
                 flooding, the lake flood plain also differs. Lake flood plains
                 do not have floodway areas since they do not convey flood
                 discharges. However, most of the inundated area of the lake
                 flood plains is susceptible to damaging wave,action at the same
                 time. Therefore, the hazard to development is uniform through-
                 out the lake flood plain area. For this reason development
                 should be discouraged in the lake flood plain area unleiss it
                 can be constructed above the lake flood levels or otherwise
                 protected to that level. The 100 year flood level is the
                 recommended standard for regulatory programs in lake flood
                 plains as well as riverine flood plains.

                 Flood Plain Information

                      An effective flood plain regulation program, whether it
                 includes riverine flood plains, lake flood plains, or both,
                 requires a firm commitment on the part of local and state
                 governments to enforce the standards and safeguards necessary
                 in dealing with the flood hazard. This requires adequate
                 flood plain data to support the regulations and their imple-
                ,mentation. Since the beginning of Ohio's CZM program, the
                 State has given priority to the Lake Erie shoreline area in
                 its flood plain delineation program. The primary source for
                 detailed flood plain information is through the National
                 Flood Insurance Program. The U.S. Army ICorps of Engineers's
                 efforts in flood plain information have been reoriented to
                 the completion of flood insurance studies. The flood
                 insurance studies provide the detailed flood information
                 necessary for supporting local flood plain regulation
                 programs. Table 1 provides a current list and status of
                 flood insurance studies for the coastal counties. Other,
                 less detailed flood information is also available from
                 U.S. Army Corps of Engineers, U.S. Geological Survey and
                 Soil Conservation Service studies.

                                              41

              Management Considerations

                   The main emphasis of Coastal Zone Management is to promote
              the wise use of the coastal resources. The following management
              considerations are set forth in accordance with that premise.

                   1.   A local flood plain regulation program should be
                        adopted and enforced in all coastal communities
                        (municipalities and unincorporated county areas).
                        Criteria should be adopted to prohibit structural
                        development in the floodway portion of the 100 year
                        frequency flood plains. Construction in flood fringe
                        and lake flood plains should be allowed only if
                        protected to levels above the 100 year flood eleva-
                        tions, either by fill or other standard flood proofing
                        measures.

                   2.   All coastal communities should participate and
                        maintain eligibility in the National Flood Insurance
                        Program. Flood insurance coverage is available to
                        protect existing buildings against flood and flood-
                        related damages including flood related erosion damages.

                   3.   New construction in urban and other developing areas
                        should be designed such that the resultant runoff
                        from these areas would not appreciably increase
                        above levels prior to development.

                   4.   Statewide support should be continued for the
                        International Joint Commission's proposal for
                        lowering levels of Lake Erie by a diversion channel
                        in Squaw Island, New York.

                   5.   Deed descriptions for property in flood hazard areas
                        should include a statement concerning the flood-
                        prone nature of that respective property.

                                              42

                                                                                                               DATE DUE

                                                                                             GAYLORDINo. 2333                                PRINTED IN US A,

                   W0-"'DNR
                            Ohio Department of Natural Res
                                                                                                -(Dij
                                         Fountain Square - Columbus, Ohio 43
                         JAMES A. RHODES, Governor - ROBERT W. T

                                                                                                     36668
                                                                                                                    14.108