<?xml version="1.0" encoding="iso-8859-1" ?>
<doc callnum="GB459.5.E73 C37 1977">
<metadata>
	<titleStmt>
		<mainTitle nfc="0"><title>Coastal hazards</title>:<titleExt>recession, erosion and flooding</titleExt>/<respStmt>prepared for the Coastal Zone Management Program by Charles H. Carter and Bruce E. McPherson.</respStmt></mainTitle>
	</titleStmt>
	<authorStmt>
		<persAuthor mainEntry="y"><name type="surname">Carter, Charles H.</name><fullName>(Charles Henry)</fullName></persAuthor>
		<persAuthor><name>McPherson, Bruce E.</name></persAuthor>
		<corpAuthor><name>Ohio Coastal Zone Management Program.</name></corpAuthor>
	</authorStmt>
	<imprint>[<pubPlace>Columbus, Ohio</pubPlace>] :<pubName>State of Ohio, Dept. of Natural Resources, Division of Water, Coastal Zone Management Section</pubName>,<pubDate>1977.</pubDate></imprint>
	<classStmt>
		<locClass>
			<subject cat="top">Coast changes</subject>
			<subject cat="geo">Ohio</subject>
			<subject cat="geo">Erie, Lake.</subject>
		</locClass>
		<locClass>
			<subject cat="top">Erosion</subject>
			<subject cat="geo">Ohio</subject>
			<subject cat="geo">Erie, Lake.</subject>
		</locClass>
		<locClass>
			<subject cat="top">Shorelines</subject>
			<subject cat="geo">Ohio</subject>
			<subject cat="geo">Erie, Lake.</subject>
		</locClass>
	</classStmt>
</metadata>

<text xml:space="preserve">
<pb n="1" />

                hio
                epartment of
                atural
               esources                                       COASTAL ZONE
                                                              INFORMATION' CENTER

                                        COASTAL HAZARDS:

                                   RECESSION, EROSION AND FLOODING

           "M
           V,                                                          ffi I n-T
                                                                       ULL

             GB
             459.5
             . E73
             C37                                                                                                  I 00"W"A OMNI I
                                                                                                    13
                                                                                            lu

                                                                                                      MW

             1977

                                                                                            Ohio Coastal Zone Management Program
<pb n="2" />

               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
                                               C
                                                                U

     0  W

        @15        JAMES A. RHODES, Governor ROBERT W. TEATER, Director WAYNE S. NICHOLS, Chief
<pb n="3" />

                                               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
<pb n="4" />

                    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
<pb n="5" />

                    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
<pb n="6" />

                        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                       &lt;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
<pb n="7" />

           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
<pb n="8" />

                                       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
<pb n="9" />

           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
<pb n="10" />

               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
<pb n="11" />

          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
<pb n="12" />

                                        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
<pb n="13" />

		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
<pb n="14" />

                    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
<pb n="15" />

          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
<pb n="16" />

                                 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.
<pb n="17" />

           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
<pb n="18" />

               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
<pb n="19" />

          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
<pb n="20" />

               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
<pb n="21" />

                                       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
<pb n="22" />

           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
<pb n="23" />

               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
<pb n="24" />

               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
<pb n="25" />

                                       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
<pb n="26" />

          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
<pb n="27" />

               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
<pb n="28" />

                                         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
<pb n="29" />

                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
<pb n="30" />

               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
<pb n="31" />

          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
<pb n="32" />

             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
<pb n="33" />

                                    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
<pb n="34" />

          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
<pb n="35" />

              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
<pb n="36" />

                           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
<pb n="37" />

                                         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
<pb n="38" />

               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
<pb n="39" />

              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
<pb n="40" />

                 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
<pb n="41" />

             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
<pb n="42" />

          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
<pb n="43" />

                                                                                                           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
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