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.9.,6;A <br /> AGENDA ATTACHMENT 5 <br /> MANAGERS REPORT <br /> WEED INFESTATION OF LAKE ORANGE <br /> Shortly after Christmas received a complaint from a person owning pro- <br /> perty on Lake Orange concerning weed infestation at the Lake. This person <br /> asked would the County take the necessary steps to resolve the problem' In <br /> the summer this weed covers a large Portion of the Lake's surface, and seriously <br /> interferes with recreational activities there. I asked the Extension Service for <br /> assistance with this problem. The weed was not readily identifiable, but now <br /> they are satisfied it is the "Southern Naiad". The weed is not native to this <br /> area and is not located in nearby waters. Since Lake Orange is a water supply, <br /> treatment of the condition, if that ig the course selected, will be difficult., <br /> There are three possible methods of treating this condition: <br /> 1. A winter water drawdown of some six to eight feet. As the <br /> Lake is the primary source of the water for Hillsborough and the <br /> Orange Alamance Water System, this procedure is a calculated risk. <br /> This winter we are experiencing a severe drought. A drawdown of <br /> six to eight feet during the winter months to allow the weed to <br /> freeze, (it only grows in shallow water) results in removing about <br /> one half the water in the Lake. If the winter is not severe not <br /> much is accomplished. If the spring is dry we enter the summer <br /> with only a partly charged Luke. <br /> If a winter drawdown were done we might consider deepening <br /> the Lake along the shoreline to three feet' This action would <br /> eliminate most of the problem but would be prohibitively expensive. <br /> 2. Chemical Treatment: <br /> This treatment is moderately costly (S8OOO-lO,UVO 'for chemicals <br /> alone) but also introduces a hazardous material into the community <br /> water supply. The treatment should be applied during the spring <br /> just as the weed starts to grow. To reach the entire weed crop the <br /> Lake should be nearly full. Yet this is the wettest time of the year. <br /> As the treatment continues for a ten day period we cannot know with <br /> reasonable certainty a hard rain will not cause the Lake to over' <br /> flnw and introduce quantities of chemically treated water into the <br /> drinking water system. <br />