Total maximum daily loads, sediment budgets, and tracking restoration progress of the north coast watersheds
This article is part of a larger document. View the larger document here.Abstract
One of the predominate water quality problems for northern coastal California watersheds is the impairment of salmonid habitat. Most of the North Coast watersheds are listed as “impaired” under section 303(d) of Clean Water Act. The Clean Water Act requires states to address impaired waters by developing Total Maximum Daily Loads (TMDLs) or implementing another program that will result in the attainment of water quality standards. TMDLs are an estimate of the maximum load necessary to meet water quality standards. In a general sense, a TMDL and its implementation plan is a water quality attainment strategy and provides a framework for assessing the watershed condition, evaluating the sources of pollution contributing to the water quality impairment, and developing a water quality restoration plan for the watershed.
Sediment budgets are useful tools to evaluate sediment impacts to water quality and channel morphology. As part of the TMDL development process, sediment budgets have been developed for twenty northern California watersheds. Anthropogenic activities such as logging and its associated road building, which commonly occur in this region, have dramatically increased sediment loading rates. TMDL studies estimate that is will take several decades or more for streams to transport the excess sediment out of the watersheds.
Tracking recovery of the watersheds from sediment impairments over time will be difficult. The Regional Water Board will use several tools to verify that progress is being made. These tools include sediment budgets, as well as monitoring hillslope and water quality conditions in the listed watersheds.