WATER-QUALITY IN MILWAUKEE, WISCONSIN, VERSUS INTAKE CRIB LOCATION

The pollution plume outside Milwaukee Harbor, Wis., is investigated ba sed on data for ammonia, chloride, and turbidity collected by the Milw aukee Metropolitan Sewerage District (MMSD) through the period 1983-94 . Results of stepwise multiple regression show that the turbidity at s tation OH-13,B close to the Howard intake crib is strongly correlated to the turbidity at station OH-02,M in the outfall area of the Jones I sland Wastewater Treatment Plant. For chloride the correlation is also significant, and for ammonia it is insignificant at OH-13,B but measu rable at station NS-07,B close to the Linnwood intake. Kriging interpl ation is used to obtain pollution estimates at unsampled locations dur ing average spring conditions and during two episodic spring runoff ev ents in 1985 and 1987 for which conditions may have been similar to th ose during the 1993 cryptosporidiosis outbreak. The results show that improved water quality can be obtained by extending the present Howard intake pipe up to 4.64 km and/or relocating the intake pipe about 2 k m south of the present location at a larger bearing (N 71 degrees E) r elative to the north-south direction.