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loading from the watcrshed, a largc art�ount of phosphorus has been adsorbed by the sediment in <br />the lake. If the nutrient load from the watershed is recfuced — always a�ood idea — and its <br />concentration in the water drops, phosphorus release from the bottom sediments of the lake can <br />become an irr�portant nutrient source for the algae. This delays the response of the iake water <br />concentration ta the reduction of loading from the watershed. There are other ecological <br />mechanisms assaciated with the biology of a disturbed lake that tend to perpetuate a turbid �vater <br />state as well_ <br />This is not to say that reducing the flow of nutrients from a lake's watershed to the lake should <br />not be done. Reduction of incoming nutrients and other pollutants ta urban lakes is always a <br />good idea_ Tt c�oes mean that careful consideration of the costs and ]ikely benefits (some of <br />which may take a lonb time to appear) is needed. In addition, a lake system itself is inherently <br />variable over time due in part to differences in precipitation and temperature patterns as well as <br />land mana;ement activities in the watershed. Thus, visible improvements may follow a"two <br />steps forward, one step back" irack. Finally, it means that no single action is likely to change an <br />urban �ake dramatically. There are numerous "tools in the toolbox" and nnany need to be used in <br />order to generate an improvement in lake quality, especially in lakes that have been severely <br />impacted for alon� period of time. <br />Or�anization af Management Options <br />A matrix of management options was developed to guide future manage�nent activities for <br />Langton and Bennett lakes_ The options are based on the results of field surveys, watershed and <br />zn-lake water quality modeling, and — most importantiy — on actual experience in restoration <br />efforts on urban lakes elsewhere in the Metro area and the upper midwest. The management <br />options are assi�ned to one of three phases. Those in Phase I can be pursued now with no little <br />or no additional resources from the City, supplemented perhaps by volunteer assistance. Options <br />assigried to Phase 2 are more costly and in some cases require a more detailed assessment <br />beyond the scope of this study. Those assigned to Phase 3 require a significant commitment of <br />financial resources and may not move farward unless supplemental outside funding is secured. <br />Also, additional �vork to esta�lish feasibility, re�ne costs, and develop de�i�ns will Iikely be <br />necessary. In most cases, these nnana�ement actions can also be expected to have the great�st <br />potential for improvin� the quality of the iar�et resource. <br />City of Roserille �3 <br />Parks Natura112esorrrce tblcrracrgement <br />