02-07-1977 Planning Packet - Laserfiche WebLink

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V. ■ i. .vw nsporttd on • aoon ro- no eattaila ubaargod cut or torn man kinda, are not weeda in opean kinda are lutoonia t propagatea ir* The ateno jid drift aaliore* ied« The leaf Dugh their ependent• B in the aquatic Bto food for *eaa than where ihwater ahrinp ; naterial* ly nests of narshy areas ler nutrient algae for the r if too aany Some kinds of chenicals. (ae, give off ih and other les and reeds« Ids and tubers Lly valuable and ixcellent shelter I enjoy* The » waterliliest >th as oma* 1 include aquatic i r-- I. V; 'i: I*- -■ I) it I < it.' ^mi/?,-//. ; 1 Bconewic values—Wild rice, which is an emergent aquatic plant, produces seeds that dre hand harvested* This local industry is worth at least €2 million to the economy of Minnesota* Aquatic plants are the basis of much of the fishing on which more than 1100 million per year is spent in Minnesota* Factors Influencing Plant Abundance Excessive growths of aquatic plants are caused by a combination of factors* All aquatic plants require suishine, water, and chemical nutrients* Rooted forras also need a suitable substrate or soil* The kinds and concentrations of plant nutrients are very important in determining the abundance of aquatic plants* The nutrients needed are the same general types necessary for the growth of land plants; such as phosphate, nitrate, potassium, cal* cium, etc* The source of these nutrients, under natural conditions, is the soil of the surrounding watershed* Nutrients are dissolved as water flows over or percolates throu^ the soil and they reach a body of water in surface runoff and in the flow of ground water* For this reason lakes and ponds in areas of high soil fertility, such as southern Minnesota, are more apt to develop excessive growths of aquatic plants than are waters in less fertile northern forest areas* In lakes and ponds these nu* trients accumulate in the water and in bottom soils* The pattern and amount of rainfall and surface runoff in a given year influences the nutrient supply to a lake or pond and the availability of stored nutrients* During periods of heavy riinfall nutrient supplies tend to be greater because of in creased runoff and because nutrients may be released from flooded soils* If there is little rainfall and water levels are normal, nutrient levels are not increased and plant*growth is stabilized* Conversely, continued low water levels can promote plant growth by making more shallow water areas and submerged soil available for the growth of water plants* Activities of man also influence the growth of aquatic plants* Intense culti vation and fertilization of land surrounding a body of water can increase the growth of aquatic plants by providing them with more nutrients than they would normally re ceive* Nutrients in wastes such as effluent liquids from sewage treatment plants and drainage from septic tanks can also promote pleuit growth* Drainage from barayards and livestock feed lots likewise can add to the fertility of a body of water* For these reasons lakes and ponds that had no serious weed problems in their natural state may sometimes develop problems because of human activities* Water depth and clarity have a strong influence on plant growth* All green plants require light to manufacture food* Rooted submerged aquatic plants therefore will letot grow well in water too deep for light to penetrate or in water that is excessively tur bid or colored* In most Minnesota lakes vegetation does not grow at depths greater than 15 feet. Lakes and ponds with clear water and shallow basins often have bottoms that are completely covered by vegetation* In some lak<^<> free-floating plankton algae may become so abundant that they create a "bloom" that ol^ds the water and shades out submerged aquatic plants. Growth of plankton algae r^noted and sustained by nu trients continually being added to the water* Such nut> ^ents can come from the bottom soil in shallow water, from runoff from adjacent lands, fr^m wastes, and from stirring up of the bottom by such fi rhes as carp and bullhead'll>• Rooted plants require a suitable soil to grow on* Certaxn species of plants are quite specific as to type of bottom but most kinds prefer a mixture of mucky organic soil and sand or gravel. Generally, as a lake or pond ages and organic material accumulates on the bottom, conditions become more suitable for the growth of rooted S'/,’;'-"" , .i I slow process n The kinda water chemistr mota, others g auch as are fo The facto are related no also to the na Under Min property of tfe Natural Resoui Order on aquat Applicati condition or 1 partment of Na on forms provj 390 Centennial automatic* A] for evaluatioB area to valuat other lakeshoi Once a pe fore control c be notified aa signs fumishc of the treatec required to rc amount of chea area after the The Depai control of aqi: provides genei of Natiiral Rea or arbitrate x work rests v .t The costa property oimei villages, bore General infom There ara controlled: bi usuadly suit at such as cuttin u4_WTL