Relationships between military land use and storm-based indices of hydrologic variability

This paper examines the influence of military land use parameters on dimensionless indices related to storm flow, baseflow, and precipitation for five watersheds with areas ranging from 0.76 to 25.01 km2 within the Fort Benning Military Installation in southeastern US. Average magnitude and variability of these indices are grouped into four key hydrologic regimes-magnitude, frequency, duration, and rate of change. Correlation and regression analyses were performed to determine the relationship among the watershed physical characteristics and indices. A number of significant relationships were found. The correlation results show that the increase in road density increased the variability in the peak discharges and the slopes of the rising limb. The increase in the military training land increased the variability in the time base. The number of roads crossing streams is positively correlated with the response lag. Stepwise multiple correlations showed that the storm-based magnitude and variability in peak discharge, baseflow index, and the bankfull discharge have been significantly affected by military management related watershed characteristics. The relationship among the watershed physical characteristics and the storm-based hydrologic indices indicated that the greatest impact of land management is found with statistically significant predictive models for indices of time base, response lag, and time of rise. Military training land, road density, and the number of roads crossing streams were the three management variables that impacted storm responses.