A WATER QUALITY ANALYSIS OF AN URBAN POND IN THE CITY OF SPOKANE, WASHINGTON

We investigated the water quality of a pond located in a city park in Spokane, Washington. The pond, which has a greenish-tan and cloudy appearance year round, typically contains a large waterfowl population and their waste has contributed to the decrease of the water quality. In an effort to improve the water quality, the City of Spokane removed dozens of birds and posted no-feeding signs around the pond. To investigate the current status of the pond, we measured pH, temperature, alkalinity, and metal concentrations of filtered and unfiltered samples. Concentrations of As and Fe were below EPA’s aquatic life standards. Concentrations of Fe, P, and Mn were positively correlated in the unfiltered samples which indicate their presence in the fine sediments in the water. Phosphorous was at high enough concentrations, 0.097 mg/L, that eutrophication of the pond may occur. To improve the quality of the pond water and its appearance our study suggests that removing and treating pond sediments and suspended particulates may help to reduce the sorbed nutrients, like phosphorous, that lead to algal growth. Developing a method to manage nutrients sorbed to suspended pond sediments will help solve problems associated with stagnant pond algal growth, both in and out of urban areas.