Turbidity standards are essential for measuring and analyzing water quality.  In Rockbridge County, monitors are collecting field data but currently have no standards to determine what is acceptable, or to correlate with declines in macroinvertebrate indicators or other stream impairment criteria.  Standards would also help improve the success of TMDL implementation plans in addressing erosion, storm water management, and sedimentation impacts on existing and designated stream uses.

Since as much as half or more of suspended load may be mobilized during storm events, it will also be important to provide guidance on sampling protocols to accurately account for variations in turbidity and provide insight into watershed-specific contributions to turbidity.

Standards for field measurements made with a secchi disk or other qualitative methods, as well as numerical nephelometric measurements should also be considered.  

I urge DEQ to promptly complete the process of developing turbidity standards and protocols that protect Virginia’s citizens, wildlife, and the water quality and health of our streams, rivers, and Chesapeake Bay.