TMDL

The Total Maximum Daily Load requirements for Rainbow Creek can be found HERE on the San Diego Regional Water Quality Control Board's website.  A Total Maximum Daily Load (TMDL) is used to address water quality impairments in creeks and rivers.  The TMDL for Rainbow Creek addresses the Total Nitrogen and Total Phosphorous levels.  The TMDL allocates or assigns stormwater pollution sources in the watershed.  It also provides the framework for taking action to reducing the stormwater pollution entering the creek and, thus, restoring the health of the watershed.

Rainbow Creek was placed on the list of impaired water bodies (the 303(d) list) in 1996 because it was found that the water quality was such that the beneficial uses of the creek were impaired.  The San Diego Regional Water Quality Control Board's Water Quality Control Plan for the San Diego Basin (9) (otherwise known as the Basin Plan) lists the nutrient concentration levels that are deemed acceptable for San Diego creeks and rivers (including Rainbow Creek).  The nutrient concentrations found in prior to and in 1996 exceeded the Basin Plan limits and, thus, Rainbow Creek was placed on the 303(d) list.  In addition to impairing the beneficial uses, the high nutrient concentrations also caused excessive algal growth in sections of the creek, which impact the natural ecosystem of the waterbody.

For more information regarding TMDLs and Rainbow Creek, please visit the San Diego Regional Water Quality Control Board's TMDL by clicking on the SDRWQCB's logo below.

                                                Last Updated: June 10, 2008