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Aquifer storage recovery (ASR) was tested in the Santee Limestone/Black Mingo Aquifer near Charleston, South Carolina, to assess the feasibility for subsurface storage of treated drinking water. Water quality data obtained during two representative ASR tests were interpreted to show three things: (1) recovery efficiency of ASR in this geological setting; (2) possible changes in physical characteristics of the aquifer during ASR testing; and (3) water quality changes and potability of recovered water during short (one‐ and six‐day) storage durations in the predominantly carbonate aquifer. Recovery efficiency for both ASR tests reported here was 54%. Successive ASR tests increased aquifer permeability of the Santee Limestone/Black Mingo Aquifer. It is likely that aquifer permeability increased during short storage periods due to dissolution of carbonate minerals and amorphous silica in aquifer material by treated drinking water. Dissolution resulted in an estimated 0.3% increase in pore volume of the permeable zones. Ground water composition generally evolved from a sodium‐calcium bicarbonate water to a sodium chloride water during storage and recovery. After short duration, stored water can exceed the U.S. Environmental Protection Agency maximum contaminant level (MCL) for chloride (250 mg/L). However, sulfate, fluoride, and tri‐halomethane concentrations remained below MCLs during storage and recovery.

From 2005 to 2006, the U.S. Geological Survey worked cooperatively with the South Carolina Department of Transportation in Beaufort and Colleton Counties, South Carolina, to assess the performance of 4 different structural devices that served as best management practices to mitigate the effects of stormwater runoff on waterways near State roads. The South Carolina Department of Transportation is required to address the quality of stormwater runoff from Statemaintained roadways as part of the National Pollutant Discharge Elimination System stormwater program mandated in the Clean Water Act. The performance assessment of the 4 structural best management practices was based on storm flow measurements and chemical analyses of storm-waterquality samples collected over a 20-month period from March 2005 to November 2006 that represented a range of seasons and rainfall intensities. A total of 49 sample sets that included storm water from the inlet and outlet of each of the 4 structural devices were collected as flowweighted composites to provide event-mean concentrations of suspended sediment, nutrients, and trace metals. In addition, each set included grab samples that were collected to provide the "first-flush" concentrations of oil and grease and fecal indicator bacteria.

No abstract

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