Agenda - 11-01-1993 - VIII-A - Laserfiche WebLink

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{ ti conditions. The drainage area, percent imperviousness, and average annual t! loads are summarized for each jurisdiction. s 1. ?a3 Under average rainfall conditions, the existing land use pattzrn is estimated to produce total-P discharges into Lake Michie of about 20 tons per year while total-P discharges into Little River Reservoir are about 12 tons per year These estimates represent the medium, or most likely, loading rates based upon application of the medium nonpoint pollution loading factors. The high (95th percentile) and low (5th percentile) loading factors produce annual total-P loading estimates ranging from about 10 tons per year to 55 tons per year for Lake Michie and about 5 tons per year to 30 tons per year for Little River watershed. Average annual total-N loads are approximately 235 tons per year for Lake Michie and 130 ton per year for Little River watershed. Metals loadings are directly related to the amount of urban development within the watershed. Under existing conditions, less than 5% of the watersheds is developed, therefore, metals loadings are relatively low. 4= Medium estimates of lead and zinc loads discharged to Lake Michie are 1.1 tons per year and 3.1 tons per year, respectively. Little River Reservoir, which has slightly less urban development receives approximately ' S1 0.7 tons per year of lead and 1.9 tons per year of zinc. The high (95th percentile) and low (5th percentile) loading factors.produce a range of lead discharge estimates of 0.8 ton per year to 1.8 ton per year_-for lake, Michie and 0.5 ton per year to 1.0 ton per year for Little River Reservoir. _ Comparisons of future and existing loadings presented later in this report • will show that the relative impacts (e.g. , percentage increase) of different land use alternatives are the same for medium, low, and high • loading factors. ' <f 3-29