Main 1-2 Rouge Storm Water Management Area

Hydrology. At two Main 1-2 stream gages, Maple Road (US4) and Beech Road (US5) the mean streamflow recorded in 2002 was the lowest recorded since 1994 and was approximately 50 percent of the 1994 through 2001 average. The mean streamflow during the 2000 monitoring period remained the highest recorded since 1994. In the Main since 1994, 2000 remained the wettest season on record and 2002 was the driest season on record. The precipitation total in 2002 was 59 percent of the long-term average precipitation total for 1994 through 2001.

Water Quality. In 2002, continuous DO and water temperature monitoring was conducted at Beech Road (US5) and has been collected annually since 1997. Continuous and grab DO monitoring at Maple Road (G45) from 1997 through 2001 and at Lahser Road (M03) from 1994 through 2001 were also included in trend analysis for the Main 1-2 SWMA. The DO concentrations in the Main 1-2 SWMA are improving during both wet and dry weather conditions. In particular, conditions have improved significantly starting in 1998 after upstream CSO control activities were completed. Sampling conducted prior to 1998 showed frequent occurrences when the DO dropped below the State water quality standard of 5 mg/L. In 2002, nearly 100% of the continuously monitored DO recorded at Beech Road (US5) met the State standard. Continuous temperature monitoring did not exceed a maximum temperature of 29.4°C (85°F).

E. coli. In general, E. coli bacteria levels have been poor in the Main 1-2 where a substantial percentage of measurements taken since 1994 have been above the State water quality standards for both total and partial body contact recreation. Overall, concentrations of E. coli bacteria are improving in the Main 1-2, with the possible exception of two sites on tributaries to the Main Rouge River and one site several miles downstream from CSO control activities. Substantial improvement is occurring directly downstream of now controlled CSO outfalls, particularly during wet weather. Generally, although improving, bacteria levels are still not meeting State water quality standards for partial body contact recreation of 1,000 cfu/100 ml.