Orange County NC Website
Browse       Search
~J <br />Nutrient Se?rs'tive Water <br />• State surface water classificati\ <br />• Jordan Lake designated in 1983 <br />• 1997 Clean Water Responsibility Act ( 515) ~ <br />- Set nutrient limits (TP = 2 mg/L. TN = 5 5 mg ) <br />- Option to develop a nutrient response model to <br />iustify different nutrient limits <br />Model I ation of <br />Current Condi iops <br />(annml average) \\ <br />Percent Days \ <br />> 40 pg/L <br />(~ 0-5 <br />O 5-10% `\ <br />10-15% u~ "Xr <br />15-20^/0 j~. - <br />20-30% <br />30-00% <br />• Federal requirement under Clea~ater Act <br />• Upper New Hope Arm of Jordan La <br />designated in the 2002 303(d) List <br />• Impairment based on chlorophyll a Stan qrd <br />• Modeling indicates both nitrogen and <br />phosphorus are co-limiting factors <br />Nutrient Res nse Model <br />• Developed by Tetra Tech, Inc \\~ <br />• Originally funded by nine mumclpal Ces~at\ <br />about $400,000 total project cosC <br />• Coupled hydrodynamic and water qualit <br />model (EFDC and WASP) <br />• Model simulates conditions from 1997 to <br />2001 <br />. Model endpoint is chlorophyll a in the lake <br />Modulation of <br />Current Conditions <br />(growing season average) <br />Percent Days <br />> AO pglL <br />0.5 % rc <br />w <br />O 5-10% ' <br />10-IS% <br />O 20-30% <br />O 30-00% <br />W_ ater flu lid ty Management <br />Plannin Cycle <br />~_ <br />0 , ~, <br />tat ~ M1M1 rat n, '' <br />4 `~A loll r1J' ~\ <br />E <br />II <br />~ ~~ i* <br />Gi it,I 'uc ri bb ~~~ <br />P .~~ntlrl : P,t,, : 2d t vti <br />i <br /> <br />