The Pressure of Society on Water Quality: A Land Use Impact Study of Lake Ripley in Oakland, Wisconsin

Abstract

Eutrophication of lakes occurs naturally over time, but the eutrophication rate can be accelerated by human activities. Agriculture land use can negatively impact water quality of lakes due to nutrient pollution. This research investigates the impacts of agricultural land use on the water quality of Lake Ripley in Oakland, Wisconsin from 1993 to 2011. This study performs a regression analysis which incorporates four years of National Land Cover Database (NLCD) data, eight spatial categories based on hydrological flow length across topographic surface, and a weighting technique to calculate land use percentages. The results indicate that the combination of agricultural land use and rainfall variables are significantly related to chlorophyll a and total phosphorus concentrations, while these variables do not appear to affect Secchi depth measurements. Due to the near flat topography of the Lake Ripley watershed, agricultural land use within the two spatial regions closest to Lake Ripley and its inlet stream had the largest impact on Lake Ripley's water quality.

Keywords

• Agriculture
• eutrophication
• Lake Ripley
• land use
• nutrients
• trophic state index
• National Land Cover Database
• and water quality