Showing papers by "Minnesota Pollution Control Agency published in 1987"

Analysis of regional patterns in lake water quality: using ecoregions for lake management in minnesota

Abstract: Developing lake management strategies that have utility across diverse geographic areas is difficult. For example, with over 12,000 lakes in Minnesota, determining carrying capacities, restoration goals, and lake protective standards cannot be practically made on a lake-by-lake basis. In light of this, the aquatic ecoregion approach was employed to assess regional patterns in watershed characteristics and inlake parameters such as phosphorus concentration, Secchi transparency, and lake mixing pattern. This approach defined seven distinct ecoregions, of which, the following four contain the majority of lakes in Minnesota: Northern Lakes and Forest (NLF), North Central Hardwood Forests (CHF), Western Corn Belt Plains (WCP) and the Northern Glaciated Plains (NGP). Analysis of total phosphorus data from approximately 1,100 lakes by ecoregion resulted in the following median epilimnetic concentrations: NLF – 23 μg P/L, CHF – 50 μg P/L, WCP – 121 μg P/L, and NGP – 176 μg P/L. Lake mixing patterns may b...

Operational problems with a soil filtration system for treating stormwater

Abstract: This paper discusses the use of a soil filtration system constructed to provide additional treatment of urban stormwater following sedimentation. The system was constructed with a Clean Lakes Grant to remove solids and phosphorus from urban stormwater. The system showed severe operational problems following initial construction. During 1985, Minnesota Pollution Control Agency (MPCA) staff determined that proper system operation required corrective measures. A low cost renovation of the system was undertaken during the spring of 1986. Following filter renovation, a monitoring program studied filter efficiency in removing phosphorus and particulate matter. The renovated system operated well the first month, but following a week-long shutdown of the system, aerial hydraulic loading rate and filter efficiency decreased substantially. After three months of operation it was apparent that the renovation was only temporary because of an improper type of peat used in the system. Peat sand filters have bee...

Incorporating cost–benefit analysis of best management practices for lake management: a negotiation approach

Abstract: Assessment of costs and benefits of lake restoration techniques aids lake management by identifying the most cost effective approach, determining who benefits from the approach, and identifying who should pay for the approach. Traditional lake restoration techniques rely upon fairly straightforward methods for determining costs of the project and identifying the benefits. However incorporating nonpoint source controls into lake water quality management strategies requires understanding the costs of nonpoint source pollution as well as the potential benefits of different management strategies. Yet cost-benefit analyses of nonpoint source pollution impacts and corrective practices have traditionally focused on a narrow range of onsite costs and benefits to the owner-operator. To become an effective water quality management tool, these analyses must encompass a broader view and become sensitive to how political and social processes will influence the negotiation of economic costs and benefits. This ...