SURFACE-WATER CHEMISTRY OF THE FOREST PARK WATERSHED (ST. LOUIS, MO): INITIAL RESULTS OF THE FOREST PARK WATER QUALITY PROJECT

Forest Park covers approximately 1400 acres in St. Louis, Missouri, and is the seventh largest urban park in the United States. Until recently, surface water in the Park was isolated in many non-contiguous lakes. Now the lakes have been reconnected and five wetlands created, resulting in a continuous more-natural surface-water ecosystem in the Park.

The primary water in the system is from the municipal provider of drinking water to the St. Louis metropolitan area. The water is piped into a pond at the western edge of the Park and flows approximately four km to the east where discharges into the St. Louis sewer system. The Forest Park Water Quality project was established in the summer of 2003 to monitor the water chemistry at four localities along the water course. Following the preliminary work of collaborator David Bradley, we have obtained water chemistry for five days between late October and middle November (with the generous help of Pamela Weston). Samples were analyzed using the LaMotte field test kit for water temperature, pH, alkalinity, calcium, nitrogen, dissolved oxygen, carbon dioxide, phosphate, chlorine, sulfide, and silica. Concentrations of the latter three constituents have been consistently below the detection limits and thus are no longer monitored each time.

Several general observations can be made from the limited data set. First, the pH changed approximately 1 ½ to 2 units within the first kilometer of the water course. Second, the carbon dioxide concentration was zero for the first kilometer of the water course, increased to ca. 4 ppm in the second kilometer, and then increased more slowly in the last two kilometers. Third, the carbon dioxide increased and dissolved oxygen and pH decreased systematically from late October to middle November. The spatial (downstream) and temporal changes in the water chemistry might restrict some aquatic life to the latter three kilometers of the water course.