The 8,212-acre (12.8-square-mile) Ulao Creek Watershed drains north to south and spans three municipal boundaries (the Village of Grafton, Town of Grafton, and City of Mequon) before discharging into the Milwaukee River. Increasing development within these communities has altered many aspects of the natural environment, including the natural hydrology, or flow of surface water into streams and rivers. Agricultural and urbanization activities generate pollutants at numerous runoff points that eventually drain into surface water systems, especially after rain events. The “diffuse nature” of these contaminants, known as nonpoint source pollution, compounds the difficulties in not only controlling stormwater runoff, but also in assessing its impact on the environment. The contaminated, untreated water accumulates in drainage ways and is usually channeled directly into streams, rivers, and lakes. Ultimately, these contaminants filter into natural wildlife habitats and groundwater (drinking water) sources. The quality of area streams, especially during heavy rains, directly impacts both animals and people.

To assess the water quality of Ulao Creek, the Ozaukee County Land & Water Conservation Department has teamed up with UCP volunteers to monitor five sites along the Creek for turbidity, temperature, dissolved oxygen, water velocity, and biotic index. Studying these water quality parameters should indicate how effectively the Creek can support life and also determine how adjacent land uses may be impacting stream water quality. Each site has been monitored once a month (May – Sept) for the last 3 years. No definitive conclusions have been reached, but the current results indicate the following:

• Average Temperature ~ 64^oF => too warm for large game fish

• Average Turbidity ~ 10-20 NTUs => not a concern, YET

• Average O² Concentration ~ 7.0 mg/L and 76% saturation => reduced biodiversity

• Average Habitat Score ~ 37 => slightly above average

• Average Biotic Index ~ 1.75-2.0 => poor stream health