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River Gauging

River Gauging & JeffThe goal of this project is to provide water quality data to the SMS4s (Horry County, Georgetown County and the City of Conway) that lie in HUC 03040206. These data are designed to support the NPDES Phase II Stormwater programs undertaken by these SMS4s as covered by SC DHEC Permit #SCR030000. The data will be used to assess: (1) site-specific "normal" conditions for the Waccamaw and Pee Dee Rivers, (2) long-term trends, and (3) the occurrence of illicit discharges.

The data are collected via biweekly sampling at 8 sites within the Waccamaw and Pee Dee River basins. Measurements of temperature, conductivity, dissolved oxygen and pH are made in situ. Depth- integrated grab samples are returned to the lab for analysis of: (1) nutrients (filtered TN and TP), (2) chlorophyll (and phaeophytin), (3) bacteria (Fecal Coliform), (4) 5-Day Biochemical Oxygen Demand (BOD5), (5) turbidity, and (6) water toxicity. Validated results are provided to the SMS4s and the public at this site. Data collected concurrently, include water quality, height, velocity and discharge by the USGS. The former are collected at 15-min intervals. SC DHEC samples are collected monthly, with some sites being active only during basin study years, the last of which was 2008. Grab sampling is staggered with the SC DHEC schedule such that the pooled data represent three samplings per month.

Other project deliverables include: (1) an annual report containing a data summary, statistical analyses of temporal trends, exceedances of known water quality standards, a narrative interpretation and (2) emergency notification if sample results exceed SC DHEC's water quality standards or the US EPA's recommended water quality criteria.


For a map of our sampling sites, interactive graphs of our data, and our Quality Assurance Project Plan, go here.