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B. Impacts of Ground-Vltater Base Flow on VNater Supplies and <br />Aquatic Life (ERCD, County Engineer, Planning, OWASA} <br />Providing assistance to the County Engineer regarding base flaw to streams, and <br />impacts on water supply and aquatic resources, should be helpful. Base flow is <br />the ground-water component of stream flow, and it sustains stream flow during <br />dry periods of the year. Base flaw studies of streams in the county would assist in <br />management of surface water based supplies (reservoirs), especially during <br />draughts. <br />C. Impacts of Land Use Patterns on Flooding (ERCD, Planning) <br />Flooding and drought are both extremes, but the underlying mechanisms and the <br />ways to address these hazards are different. In the case of floods, monitoring of <br />changing land use patterns -- and the passible resultant effects on intensity of <br />flooding and increase of flood-prone areas - is a priority need. This function <br />could include review of FEMA floodplain maps and evaluation of any unmapped <br />streams where new development may result in increased potential for floods. <br />Following flood events, indirect measurements of peak flood heights should be <br />made, and related to recurrence intervals determined by the USGS, Corps of <br />Engineers ar other responsible agencies. These data need to be compared to <br />any existing flood-prone area maps to ensure their accuracy, especially in areas <br />undergoing development. Additional areas that may need to be mapped should <br />also be identified. <br />Issue 2. Ground-Water Contamination and other Threats <br />Along with an adequate supply of water, it is also important that water be fit to <br />drink. The 2002 State of the Environment Report noted that only 45% of reported <br />groundwater contamination incidents have been "closed-out," due largely to State <br />staf~rng limitations. The 200? USGS Study also found elevated radon in ground <br />water samples that may warrant further study, along with more detailed sampling <br />for organic contamination to more accurately assess the status of our ground <br />water quality. To the extent that these hazards exist, it is urgent that the County <br />ensure that its citizens are protected. Therefore, the Water Resources Initiative <br />proposed the fallowing actions; <br />A. Further Research on Elevated Radon Findings {ERCD, Health) <br />One of the findings of the 2001 USGS cooperative study {"Investigation of <br />Ground-Water Availability and Quality in Orange County, NC") was that in some <br />areas of the County there were elevated levels of radon, a situation that could put <br />residents of those areas at great risk. Of the total wells sampled, 67% of the <br />radon analyses in the study exceeded the USEPA proposed maximum <br />contaminant level {MCL) of 300 pCi/L (picocuries per liter). In addition, the <br />3 <br />