Laserfiche WebLink
<br />100 <br /> <br />west). Because of this natural isolation they have been a focal point of <br />adaptation for plants and animals exploiting the resources of ~ter, food, <br />cover and nutrients. As wildlife habitat, wetlands provide cover, shelter, <br />feeding, breeding areas, spawning and nursery si tes, and feeding and resting <br />sites for migratory species. <br /> <br />Shoreline Protection and Erosion Control <br /> <br />Several investigators have documented the shorelin" protection and <br />erosion control function of wetlands (Carter et al., 1978, Novitzki 1978). <br />Erosion is the result of natural events such as heavy precipitation, <br />flooding ~.d wind generated ~ves, but may be accelerat',d by many man-caused <br />activities including water level manipulation, agricultural clearing and <br />drainage, channelization, homesite or industrial development, placement of <br />roads and railroads and poor placement of groins and warer control snd <br />diversion structures. There is substantial evidence that native wetland <br />plants bind soU both under and above the water, reduce current and wave <br />energy by friction, increase deposition of sediment by slowing the current, <br />and stabilize banks. Erosion is naturally cCllItrolled by vegetation that <br />I) binds and stabilizes substrates, 2) dissipates wave and current energy, <br />and 3) traps sediment. <br /> <br />Flood Storage and Storm Flow Modification <br /> <br />There are few studies that quantify the .flood modUication eff',cts 0 f <br />wetlands, however, wetlands in drainage basins do provide flood storage and <br />storm flow..lIOdificatlon in varying degrees through temporary. storage of <br />surface water, aquifer recharge, and deCreaSE! in water '~elocity (Figure 5). <br />Flood peaks have been shown to be significantly lower in basins with <br />substantial ~/'atland and lake area than in basins with no wetland or lake <br />area (Novitzke 1979). The reduction in flood flow is r"lated to the amoun t <br />of wetland and lake acreage in a watershed bE!CaUSe both ecosystems are flat <br />and there is a short term detention storage 011 the surface and in the soil <br />horizons. The storage capacity of wetland soil is related to the water <br />table"in the soil profile, whether the soil ill organic: <lr mineral (Verry and <br />Boelter 1978). The.leaat runoff occurs when the water .table is low beclluse <br />there 18 greater .tor.... "cia1lAelty and the gr.!.test runoH occurs when the <br />water table is high with little storage capac:Lty. <br /> <br />.. <br />~ <br />E <br /> <br />. <br />S <br />.. <br /> <br />~ "En.A"". <br />~.O ""'rI.A.OS <br />".IN 'TOAM <br /> <br />r......-"S:.-eo.,arUOD of flow rata followlll& II ntn .tonl <br />in _... "t" .nd without ..tI...... ' <br />