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7 <br /> ORANGE COUNTY PLANNING & INSPECTIONS DEPARTMENT <br /> Craig N. Benedict, AICP, Director <br /> ���r4e' �aaa'� <br /> Erosion Control Division 131 W. Margaret Lane <br /> (919) 245-2588 '� �: P O Box 8181 <br /> v ' az <br /> (919) 644-3002 (FAX) �� Hillsborough, <br /> www.co.orange.nc.us .�,, '� Aa North Carolina 27278 <br /> ff4 ca�A`` ' <br /> .^ <br /> �... N ' � i � '�+Al� <br /> � w..,... _ � � <br /> _ _ ��,.� ���.�w x ,�� <br /> MEMORANDUM <br /> TO: Michael Harvey, Current Planning Supervisor <br /> FROM: Terry Hackett, Stormwater Resource Officer� <br /> DATE: March 14, 2012 <br /> SUBJECT: Stormwater Impacts from Solar Farms <br /> COPIES: Ren ivins, Erosion Control Supervisor <br /> Craig Benedict, Planning Director <br /> Given the current economic conditions, land owners are looking for new, cost effective <br /> ways to provide income from their properties. This, coupled with an increasing <br /> awareness for sustainable practices and alternatively energy, has increased interest in <br /> solar farms. At first glance, solar farms seem to make sense from an environmental <br /> standpoint. They can be installed with minimal impact and provide clean, renewable <br /> energy. However, one concern raised about solar panels is stormwater runoff. <br /> The panels themselves are obviously impervious. Impervious surtaces generally <br /> increase the velocity of the runoff, increasing erosion potential, while decreasing <br /> infiltration. This can result in harmful effects on the aquatic ecosystem, and limiting <br /> impervious surface in a watershed is one tool used to limit impacts of stormwater runoff. <br /> However, many solar farms do not concentrate the runoff. Solar panels are often <br /> installed so that they are movable and track the sun. This allows herbaceous plants to <br /> grow beneath them and stormwater runoff to reach the ground where it can infiltrate. <br /> Unfortunately, rules may not be clear. Should panels from solar farms be included in <br /> the calculation of impervious surface? In New Jersey, the state actually passed a law in <br /> April 2010 exempting solar panels from the calculation of impervious surface. Here in <br /> North Carolina, it "depends." <br /> According to Julie Ventaloro, Coordinator of the Water Supply Watershed Protection <br /> Program for the NC Division of Water Quality, Wetlands & Stormwater Branch, solar <br /> panels mounted so that they move with the sun are not considered impervious by the <br /> state, provided there is no reduction in infiltration of precipitation. The state <br /> recommends reviewing each proposed solar farm on a case by case basis, because <br /> S:\5 Erosion Control and Water Quality\Erosion Control and Water Quality�Erosion Control Div\correspondence�2012U-Iarvey Solaz Memo <br /> 03142012.docx <br />