SOUTH CAROLINA DEPARTMENT OF HEALTH AND ENVIRONMENTAL CONTROL WATERSHED WATER QUALITY ASSESSMENT EDISTO RIVER BASIN Watershed Water Quality Assessment Edisto River Basin 2012 South Carolina Department of Health and Environmental Control Bureau of Water 2600 Bull Street Columbia, SC 29201 803-898-4300 www.scdhec.gov/water PREFACE In 1993, the South Carolina Department of Health and Environmental Control (SCDHEC) published the first in a series of five watershed management documents. The first in that series, Watershed Water Quality Management Strategy: Savannah-Salkehatchie Basin, communicated SCDHEC’s innovative watershed approach, summarizing water programs and water quality in the basins. The approach continues to evolve and improve. The watershed documents facilitate broader participation in the water quality management process. Through these publications, SCDHEC shares water quality information with internal and external partners, providing a common foundation for water quality improvement efforts at the local watershed or large-scale, often interstate, river basin level. Water quality data from the Edisto River Basin was collected during 2002 through 2006 and assessed during this fourth, five-year watershed management cycle. This updated atlas provides summary information on a watershed basis, as well as geographical presentations of all permitted watershed activities. Waterbody, monitoring station and facility indices allow the reader to locate information on specific waters and facilities of interest. A brief summary of the water quality assessments General information on included in the body of this document is provided following the Edisto River Basin Table of Contents. This summary lists all waters within the Edisto Watershed Protection and River Basin that fully support recreational and aquatic life uses, Restoration Strategies can followed by those waters not supporting uses. In addition, the be found under that section on page 27, and summaries list changes in use support status; those that have more detailed improved or degraded over the five years since the last information is located assessment was written. More comprehensive information can be within the individual found in the individual watershed sections. The information watershed evaluations. provided is accurate to the best of our knowledge at the time of writing and will be updated in five years. A major change to this newest assessment is the use of the National Watershed Boundary dataset using the 8-, 10-, 12-Digit Hydrologic Unit Codes for South Carolina. This more accurate hydrologic unit code’s use changes numerous boundaries in the basin and introduces a new numbering system for the watersheds. For comparison, each watershed evaluation will state the prior hydrologic code. As SCDHEC continues basinwide and statewide water quality protection and improvement efforts, we are counting on the support and assistance of all stakeholders in the Edisto River Basin to participate in water quality improvements. We look forward to working with you. If you have questions or comments regarding this document, or if you are seeking further information on the water quality in the Edisto Basin, please contact: Watershed Manager, Edisto River Basin SCDHEC Bureau of Water 2600 Bull St. Columbia, SC 29201 (803) 898-4300 www.scdhec.gov/watershed Table of Contents Water Quality Assessment Summary ....................................................................................................... i Introduction................................................................................................................................................ 1 Purpose of the Watershed Water Quality Assessment ............................................................... 1 Factors Assessed in Watershed Evaluations............................................................................................ 3 Surface Water Quality................................................................................................................... 3 Monitoring ......................................................................................................................... 3 Natural Swimming Areas.................................................................................................... 5 Classified Waters, Standards, and Natural Conditions ....................................................... 5 Water Quality Indicators.................................................................................................... 7 Macroinvertebrate Community............................................................................... 7 Fish Tissue .............................................................................................................. 7 Dissolved Oxygen.................................................................................................... 7 Biochemical Oxygen Demand ................................................................................ 8 pH............................................................................................................................ 8 Fecal Coliform Bacteria.......................................................................................... 8 Nutrients.................................................................................................................. 9 Chlorophyll-a.......................................................................................................... 9 Turbidity ................................................................................................................. 9 Total Suspended Solids........................................................................................... 9 Heavy Metals ........................................................................................................ 10 Assessment Methodology ................................................................................................ 10 Use Support Determination................................................................................... 10 Aquatic Life Use Support ..................................................................................... 11 Macroinvertebrate Data Interpretation.................................................................. 13 Recreational Use Support ..................................................................................... 13 Fish Consumption Use Support ............................................................................ 13 Drinking Water Use Support ................................................................................ 14 Additional Screening and Prioritization Tools................................................................. 14 Long-Term Trend Assessment.............................................................................. 14 Shellfish Water Quality ............................................................................................................... 15 Ocean Water Quality................................................................................................................... 16 Groundwater Quality .................................................................................................................. 16 NPDES Program .......................................................................................................................... 18 Permitting Process ........................................................................................................... 18 Wasteload Allocation Process........................................................................................... 18 Nonpoint Source Management Program ................................................................................... 19 Agriculture....................................................................................................................... 20 Silviculture....................................................................................................................... 20 Urban Areas ...................................................................................................................... 21 Marinas and Recreational Boating.................................................................................... 22 Mining…………………………………………………………………………………... 22 Hydromodification............................................................................................................ 23 Wetlands ........................................................................................................................... 23 Land Disposal .................................................................................................................. 23 Groundwater Contamination............................................................................................ 24 Water Quantity ............................................................................................................................ 25 Interbasin Transfer of Water............................................................................................ 25 Capacity Use.................................................................................................................... 25 Growth Potential and Planning .................................................................................................. 26 Watershed Protection and Restoration Strategies................................................................................ 27 Total Maximum Daily Load