Orange County NC Website
Browse       Search
5 <br /> Attachment C. DRAFT Water in Orange County information sheet <br /> Water in Orange County <br /> 1. Each year, Orange County receives approximately 45 inches of precipitation. This <br /> equals 1.2 million gallons of water per acre per year, or a total of approximately 308 <br /> billion gallons of water each year over the entire county! <br /> 2. Much of this precipitation flows over the ground surface as stormwater runoff, and <br /> enters waterways shortly after reaching the ground. <br /> 3. The amount and velocity of stormwater runoff increases as more impervious <br /> surfaces (roads, buildings and other hard materials) are built. <br /> 4. Stormwater runoff also increases when wooded areas are turned into lawns or other <br /> types of managed landscape. Steeper slopes also produce more runoff than <br /> flatter areas. <br /> 5. As the amount and velocity of stormwater runoff increases, the amount of soil <br /> erosion can increase, leading to more sediment in streams and lakes. Sediment is <br /> the main pollutant affecting waterways. Land disturbance, including farming and <br /> the construction of residential, commercial and industrial buildings, can also result in <br /> increased soil erosion. <br /> 6. Increases in the amount and velocity of stormwater runoff can increase the <br /> temperature of the water in surface water bodies. Adding impervious surfaces that <br /> get very warm during summer months can result in warmer water leaving these sites <br /> and affecting the fish and other aquatic organisms that live in this water. <br /> 7. Increasing the amount of precipitation that becomes stormwater runoff reduces the <br /> amount of water that infiltrates the soil and becomes groundwater, a process <br /> known as groundwater recharge. This reduction in infiltration can reduce the <br /> amount of groundwater available to residents for use as drinking water. <br /> 8. Reducing infiltration (recharge) will decrease the amount of baseflow. Baseflow is <br /> shallow groundwater that enters streams and other surface water bodies. During <br /> periods of dry weather, baseflow is the main source of water sustaining small <br /> streams. Up to 55 percent of the water present in the streams in Orange County is <br /> supplied by baseflow. Consequently, baseflow is critically important for <br /> maintaining aquatic ecosystems. <br />