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by-pass marshes, thereby curtailing the benefit to be derived from them. On the <br />other hand, by anticipating problems of localized flooding, development can be <br />restrained in those areas, storm sewers can be avoided and storm water can be <br />allowed to meander naturally through the natural filtration system of the marshes. <br />Therefore, the Harza Study recommended that "the present policy of preserving <br />lakes and marshes from filling be continued. It is further recommended that the <br />future construction of storm sewers be minimized to those required to alleviate local <br />problems. Storm runoff from the watershed should be encouraged to flow over <br />marshes, not through them in conduits or around them. <br />An attempt should be made to locate those areas adjacent to marshes which may be <br />flooded intermittently because of increased runoff caused by future developments. <br />These areas should be reserv ed from further development just as tho’igh they were <br />a portion of the adjacent marsh". <br />The Metropolitan Council's Storm Water Impact Investigation (1973) included <br />several pertinent conclusions, as follows; <br />1. The total quantity of storm water runoff will increase if present urban <br />development practices are continued. <br />2. The impact of converting an area of undeveloped land to dense <br />residential use w ill increase the pollution load from that area by more <br />than ten (10) times. <br />3. The storm water from dense residential areas averagesfourteen limes <br />greater phosphorus concentrations than the lakes, based on the <br />results of this study, other similar studies in Minnesota, and that <br />found in literature. These concentrations are over nine times greater <br />than the concentrations associated with nuisance algae blooms. <br />4. Storm water runoff accounts for almost all of the nitrogen and <br />phosphorus added to the lakes and streams. This conclusion is based <br />on average flows and quality of the effluents from sewage treatment <br />plants compared to the flow s and quality of the storm water runoff. <br />Based on this data and the previous published studies, the Storm Water Study <br />included the following recommendations; <br />I.The objectives of storm drainage design should be revised from rapid <br />disposal to concepts w hich w ill decrease the impact of storm water <br />by reducing peak flows and improving quality. <br />CMP3A- 17 <br />I <br />I <br />I <br />I