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Missouri Nutrient Criteria Development. Mark Osborn. Lakes & Reservoirs. Natural Lakes (very few) Sinkhole ponds (in karst areas) Ox-bow lakes, blew holes, wetland lakes 1 tectonic Artificial Lakes and Reservoirs ~2900 > 5 ac in area 22 > 1000 ac in area
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Missouri Nutrient Criteria Development Mark Osborn
Lakes & Reservoirs • Natural Lakes (very few) • Sinkhole ponds (in karst areas) • Ox-bow lakes, blew holes, wetland lakes • 1 tectonic • Artificial Lakes and Reservoirs • ~2900 > 5 ac in area • 22 > 1000 ac in area • 456 listed as Waters of the State
History of Reservoir Construction in Missouri (reservoirs > 10 acres in surface area) • Year Completed No. of reservoirs Percentage 1800 – 1920 122 8 1920 – 1940 267 18 1940 – 1960 68 5 1960 – 1980 909 61 1980 – 1995 121 8
Lake Regions in Missouri (12) (53) (82)
th Chl - a (25 TP Chl - a TP percentile) (median) Plains 8.2 22.5 15.4 43.9 Big Rivers 24.8 70.3 42.7 130.7 Ozarks 2.8 10.9 6.3 19.8 Potential TP criteria based on chlorophyll-a response(ug/L)
Other factors to consider • Designated Uses • Area, Depth, and Volume • Watershed size and characteristics • Residence time
Residence Time outflow 50 inflow 50 Volume 100 RT = 2 years outflow 100 inflow 100 Volume 100 RT = 1 years outflow 200 inflow 200 Volume 100 RT = .5 years