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      Department of Public Works Bureau of Sanitation
Nitrogen TMDLs

Los Angeles River

On March 23, 2004, the Nitrogen TMDL became effective and numeric targets for nitrogen compounds into the Los Angeles River were established. Reaches of the Los Angeles River and its tributaries were listed as impaired for nitrogen compounds (ammonia, nitrate, and nitrate) and related effects such as algae, pH, odor, and scum on the StateÕs 2002 303(d) list. These reaches were listed because numeric and narrative water quality objectives for nitrogen compounds and related effects were exceeded, thereby impairing warm, freshwater, and wildlife habitats, and recreation beneficial uses.

The principal source of nitrogen compounds to the Los Angeles River is from Publicly Owned Treatment Plants (POTWs). Discharges from the Donald C. Tillman Water Reclamation Plant (WRP), the Los Angeles-Glendale WRP, and the Burbank WRP are contributors to the Los Angeles River. During dry weather period, the major POTWs contribute 84% of the total dry weather nitrogen load. Urban runoff, stormwater, and groundwater discharge may also contribute to the nitrogen loadings.

A workplan will need to be submitted to the LARWQCB one (1) year after the effective date of the TMDL. Meetings with stakeholders in the watershed will be started soon to develop this workplan.