Publication Summary

During 2002 and 2003, the Department of Ecology conducted a Total Maximum Daily Load (TMDL) study for fecal coliform bacteria in the Nisqually River, the Nisqually Reach of Puget Sound, Ohop Creek, Red Salmon Creek, and McAllister Creek. A TMDL analysis was also conducted for dissolved oxygen in McAllister Creek. Results showed that the Nisqually River and much of Nisqually Reach met fecal coliform water quality standards. Ohop, McAllister, and Red Salmon creeks did not meet standards. Best management practices are recommended for bacteria reduction.

Low dissolved oxygen levels found in McAllister Creek were determined to be largely due to natural conditions.

From March 2002 through September 2003, the Department of Ecology conducted a Total Maximum Daily Load (TMDL) study for fecal coliform bacteria in the Nisqually River, the Nisqually Reach of Puget Sound, Ohop Creek, Red Salmon Creek, and McAllister Creek. A TMDL analysis was also conducted for dissolved oxygen in McAllister Creek.

Results showed that the Nisqually River and most of the Nisqually Reach met fecal coliform water quality standards and showed improving trends. Therefore, no load reductions are recommended; however, continued monitoring is suggested.

Bacteria levels in Ohop Creek have improved greatly since the early 1990s; however, load allocations were needed for several sites downstream of Ohop Lake (dry season) and one tributary, Lynch Creek (wet season).

Three of four sites on Red Salmon Creek required more stringent bacteria targets to meet freshwater and downstream marine standards.

Bacteria levels have improved in the marine water near the mouth of McAllister Creek; however, although two of the upstream sites on McAllister Creek met standards, many of the downstream sites did not. To meet stringent marine bacteria standards, a bacteria target was set at river mile 4.3. Recommendations are made for bacterial reductions in tributaries and tide gates that discharge to the creek.

Best management practices for bacteria reduction are recommended for all load reduction sites.

Low dissolved oxygen levels found in McAllister Creek were determined to be largely due to natural conditions, from a combination of low dissolved oxygen in the groundwater, wetland influence, and physical conditions that impede reaeration of water. It was not possible to quantify the anthropogenic contribution to low dissolved oxygen compared to natural background conditions. High nutrient levels in the creek may contribute to excessive plant growth and thus lower dissolved oxygen levels. Recommendations are made for control of nutrients to the creek and investigation of high nitrate+nitrite nitrogen levels in groundwater.

Link to EIM data for User Study ID DSAR1