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Monongahela River Water Quality

Kathy Knauer, M.S.

Our water quality study in 2001 focused on the upper Monongahela River from Locks and Dam #2 at Mile Point 11.3 near Braddock, PA to the Allegheny County line at Mile Point 35.

Dry Weather:

Our sampling indicates that dry weather water quality conditions are quite good. They meet our target water quality standard for recreational use most of the time. In the 2001 recreational season (May 15 - September 30), 70 of 138 days were considered safe for direct contact with river water by Allegheny County Health Department River Water Advisories. (51% of the time)

Wet Weather:

Our data suggest that in Pool 3, Mile Point 35 to 27.8, little lasting impact on fecal coliform concentrations is seen with storms less than 0.70 inches. Higher fecal coliform concentrations were seen for a wet weather event with 1.2" of rain. Pool 2 data from Mile Point 16.7 and 14.3 indicated a larger impact on fecal coliform concentrations for the 3 wet weather events sampled compared to Pool 3. Pittsburgh Pool data shows higher concentrations and apparent duration during the same sampling events than the upper pools.

Tributary Streams:

During dry weather, fecal coliform vary among the tributary streams studied. While several streams had fecal coliform concentrations under 200 CFU/100ml, three streams had samples greater than 105 CFU/100ml. Chemical and field tests indicate most parameters within an expected range for this region and within state water quality standards. However, many of these tributary streams flow through municipal parks or neighborhoods.

While the problem of fecal contamination problem is present in many the tributary streams, the ecological potential of these streams cannot be overlooked.