Drainage Density in Drift-Covered Basins

Drainage density, as determined for three drift-covered basins in north-central Wisconsin, has been correlated with mean annual flood flows and base flows. Deviations in the relationship for base flow from two basins are caused by groundwater gains and losses. Correcting for these deviations, drainage density has been related to the streamflow components of surface runoff and groundwater flow, taken as a percentage of total annual runoff. The original analysis of the data, and dimensional analysis, indicate that these streamflow components should be related to drainage density by a power function. This function is not continuous, and therefore a semi-logarithmic relationship is developed which satisfies the basic requirement that the sum of surface runoff and baseflow must be total streamflow. The results are indicative of the influences of the soils and geology of the three basins on the streamflow components.