Decade-Scale Precipitation and Streamflow Variations in the Kansas-Nebraska Region

Decade-long climate variations are natural occurrences and have contributed to the prosperity and hardship of many civilizations. Examples include the Dust Bowl years of the 1930 s and the floods of the 1940 s. Economic sectors that depend on weather and water resources are particularly vulnerable to such climate variations, include agriculture, urban and industrial water supply, hydro-electric power generation, transportation, and drought and flood preparedness. The economic and societal consequences of a long duration climate variations requires that subtle, yet sustained variations in climate be identified early, and adaptive and mitigating strategies be developed to reduce risk and enhance the responsiveness of water resource dependent economic sectors. This study reviewed decade-long precipitation variations in the Central Great Plains of the United States and establishes the relationship between precipitation and streamflow variations for rivers in the Kansas-Nebraska region. Decade-scale variations in precipitation and streamflow are identified using an 11-year moving average filter. A sizable increase in decade-scale precipitation was observed in the closing two decades of the 20th century in Central Great Plains. The signature of this precipitation increase on the streamflow was investigated for several river basins of varying drainage area. This study showed that the general trend of the decade-long precipitation is also observed in the streamflow. A correlation analysis was used to establish the sensitivity of streamflow to precipitation. Streamflow was found to be non-linearly correlated to precipitation. The degree of non-linearity and the sensitivity to years with major floods varied as a function of basin size.