Thesis

The development of artificial drainage ditches has become extensive in South Central Minnesota in the last 120 years. This study examines the effects of artificial drainage on surface water hydrology using quantitative geomorphic analysis. Eighteen quantitative geomorphic parameters and seven descriptors for 269 artificial drainage ditches were determined.

Nutrient input to a southern Minnesota hypereutrophic lake from the combined watershed of a second-order stream and an agricultural drainage ditch was monitored for a 14 month period, from July 1975 to September 1976. The stream-ditch watershed was divided into subwatersheds and the water quality of each was sampled approximately every seven to ten days during the ice free period and monthly during the ice cover period. Subwatershed flow rates were measured for each sample period and used to calculate subwatershed and total watershed nutrient loading.

Ecological information on the annual cycle of distribution and abundance in the cladoceran and copepod species in a south central Minnesota dolomite quarry was collected during 1972-1973. Collections were made biweekly except for the period of winter ice cover when they were taken at approximately monthly intervals. Biological collections were supplemented with physicochemical determinations of water temperature, dissolved oxygen, and pH. Three sampling stations were selected to physically compartmentalize the quarry waters on the basis of vertical and horizontal differences in habitat types.

This study involved the analysis of the relationships of morphometric parameters and sediment chemistry. The morphometric parameters included area, mean depth, maximum depth, volume, volume development index, shoreline and shoreline development index. The sediment chemistry analysis involved phosphorus, total nitrogen, percent inorganic, percent organic, percent calcium carbonate, and percent ash. The sediment chemistry was based on short cores from the deepest basin of each lake.