Historical Changes in the Streamflow in Kansas Streams: Variation, Causes, and Implications

Over the past decades, the streamflow characteristics in the Great Plains streams have changed substantially. These changes have affected the use and allocation of water in the watershed, as well as the lotic ecosystem in the stream network. Changes have affected and will continue to affect the management decisions within the watershed. Our study was undertaken to determine the extent of change in the median and low flows of streams across the state of Kansas and to identify the probable factors affecting these changes, as well as its implications. Several unregulated streams were analyzed by using streams with more than 60 years of daily discharge data. The analysis focused on the median and low flows of the streams. The state of Kansas was divided into four regions, representing roughly the west, central, northeast and southeast sections of the state. Several factors believed to affect the streamflow were identified and their influence was modeled over time. A multi-variate statistical model was run. The results show changes in streamflow pattern have been experienced by Kansas streams. Over the decades, western and central Kansas streams are losing flow, while the eastern streams are gaining flow. Results also show that a climate factor, in terms of water deficit, dictates the regional differences in streamflow. It was apparent that anthropogenic activities of land use, water use and water conservation practices play a significant role in streamflow changes. The role of the physical factors, such as soil type and potential recharge, cannot be downplayed. An interesting result in this study shows that the magnitude and the effects of the factors on the streamflow pattern differed across the regions of the state. There is convincing evidence that the riverine ecosystem has been affected by the changes in the streamflow patterns. Results of this study could be useful to decision makers, water users, watershed stakeholders, and environmental conservation advocates in addressing problems and concerns related to stream and river management.