02-22-1977 Planning Packet - Laserfiche WebLink

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aquatic (^osystem. the ailed eutrophication. It > in nil wetlands to a on local availability of :er the system, and the ihicution is a process ■ filling-in of lakes. As [;r supports more plant ic bottom of the water eater plant population *nger so that it is not trap the.so nutrients, peat tleposits. Under do not build up as m take thou.sands of m of a bog. ic.s can compress the an from centuries to a ts and nutrients from d damage the natural a settling basin of iter. •n is an unpleasant ►roduces smelly algae e«ds, and it depletes > the plants start to ess night, the rate of is high, no light is e oxygen is :iddf d to g or dt!con'j»().sing at ery low and kill the »nd shallower than a trients from a given flativc surface area ulimerged, fl<»aling, the bottom mud is ■al proce.sses occur , when agitated by are stirred up and conditions tend to quite sen.sitive to t filters, they can ed. 'I'his is exactly •hication. 'i'hrough itili/.er.s and urban eutniphicalion is fa.st as the natural it Would have acted M) years may cmly is overlo.»di*<l. for overland runoff hat apply to their ng wetlands will increasing the flow act t(» hold duv.'n artk le.s ir. waier- through the tangle is. 1 he reau ’ling I the natiir:.! catch joint* sedifiunl .ho ..nKtaMliiy of ,h. upland »« nfluenml by msion and the other with water and onto, fc bottom inDtorifli from b hoAlthy marsh Thnn cs»* h win clet ;nttir b^f-e lurbidity drastically reduces water quality in marshes ZLnt n, S“»P»<led pa^Ucles Xe te the bottom and thus give a nlnnt^ "if ^ Certain plant species. Top growing plants such as algae or submerged plants with*^ 1^ light rt-quimments wUl dominate. These suspended TrSa also influence the animal life in the marsh. Fish wS trt feeding-which inclu^ air he desirable game fish-wUI be seriously affected Thl scavenger fish, such as carp and suckem. Sire not ^ht f^ers, will be at an advantage. This change in fish population also adds to sflUtion. since scavenged fi^L are iS" i ‘trough the bottom as they feedand thus keep the silt in suspension. In these ways agricultural and suburban development siltation in a wetland's watershed, overload and cfegrade the wetland's natural fUtcring system. An experiment conducted in Wisconsin shLs how sUtatlon. The amount IlcdfTfi *" ^ wouldtake 16,000 years under fallow land; 27,400 years under forest: and 171,500 years under grasslands Sinerthe i^irfWH *"®ent>ve of preserving as much of the soil V speculate about the even higher rate of erosion from construction sites where no •ttch incentive exists. Even e one time silUng from constructron can have a long-term impact on^mersh ecol^y smee silt is slowly flushed out of wetlands and is «mstantly stirred np by wind and scavenger fish ami abUhv 17 ’'’”''’.'"' "’“SI l“ko into seconnt man ’s , eutrophication and sUtation of iJe.11 . k * ‘he KMl IS clean water, wc must do more than n.?l, '■ '','■“**'"8 “"<1 filling of wetlands. We cannot \v1 m^s."’ “"“""K basins or nutrient traps. W t musi mimmice nutrient inputs so that wetlands wiU ~M.nne u. act as fUters as long as ,K.ssiblo. and we m«t . “““ ''"'“"'Is "illn„re, . '’“P Mdtments from runoff. By regulating marlhll Jilh g"*""'"*, "“*• ““ <■“” "'""‘“in healthy marshes w ith diverse plant and animal communities ■ an „ «gc..n,.oK abe ,vs wiodollow precipitation ... ~~ Period ol hiQh precipitation ‘bey during dry'peS' ZZu itTnck d^ Thni krepmg the water tahio high and relatively s^ble. A wom ho has straggled to get petunias to grow in a w indow box understands how wetlands perform^his Tnlctl Pe« the organ,c material depositeel al the bottom of rweulnd k I t u ®*’f»®"*c material to window l)ox soil helps the .soil to withstand the do ing eff “u Jf til sl^l irants'™! 1'“^ ‘''1' ‘bo "ecessao moisture for the wtu inrls iisiiural sponges which reduce the risks of flooding and drought. * The complete relationship between marshes ^ounrlwater hydrology is more complicated; here wet- lands m.ay have one of three general 1haracu.ris.rs': Kiniire '* * ’“ob “''eo area for groundwater. (Sec addition..! amounts of it arc able to rep wish therihf:r;irr win 'rr "t ■- koepmg the groundwater rllXtaTr ' li ill!1 iaWaiittJi •>-lo '• » /4-. 4 - .“."IPP Water collected and stored in the wetland fiiters down to nehMrge the groundwater I. S Ground Welter is discharge to the wetland j. • V { i r^- 7 , f 'rh»* lt*\ t*l.s of u a h«' equal After ii • occurs, water will I will |H*rcol:ite into obout I he same. Al the wetland due t< somewhat by gre groundwater becon up. 'I’his process i: meadows or sh. "temporary" wetla that dry up during t hummocks of vegc capacity during pei upon contact with drought. Since thes fill, they are most them means drainir 2. The wetland is 12.) Although this overland flow, it a seepages. Such wet regions of the West, by evaporation, bul Because they are fed are likely to support higher quality than overland flow for the str.ble water level mj 3. The wetland is its basin floor is seah this case, there is m and the water table, basin for overland precipitation the basi the rest of the water c In this way it functio total amount of watc figure 13. EFFECT < i m "1. r ■■ r fc- -—I y v"' r Ms h,Ffeiwwalflfnl.e ■’dljwaihnjuqn ’: 2-. . it.fr m