IMPLICATIONS OF LAND USE CHANGE ON BASEFLOW AND STORMFLOW OF THE RED RIVER OF THE NORTH

A proactive strategy to alleviate increasing flood damage is to better understand flood pattern changes and pinpoint physical causes that are responsible for them. Among all factors, anthropogenic land use change imposes fundamental stresses on the hydrologic system. This study investigated the changes of land use patterns, baseflow and stormflow, and the correlations of land use change index with flow parameters in the Red River of the North in North America. The magnitude and timing of the respective contribution of baseflow and stormflow were estimated using recursive digital filtering techniques. The correlations between specific types of land use and variations of flow parameters were evaluated using nonparametric Kendall’s rank correlation tests. Results indicate that annual baseflow and stormflow of the Red River have increased significantly since the early 1900s. Significant correlations were documented predominantly between cultivation of seasonal row crops and baseflow. Rising baseflow levels are responsible for a majority of the streamflow increases in the Red River. The greatest increases in streamflow and baseflow in the dry and pre/early growing season of March, April, and May indicate that land use change, in particular the rapid expansion of seasonal row crops, is responsible for the elevated Red River streamflow. Transition from perennial prairie plants to seasonal row crops in the Red River basin since 1950s has reduced evapotranspiration rate and increased groundwater recharge, baseflow, and streamflow. This understanding of the temporal variations of baseflow and stormflow and the distribution of baseflow versus stormflow is fundamental to land and water resources management, and it provides information critical to alleviating the flood risks in the Red River and other rivers of the world that are affected by flooding.