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Climate change, whether natural or due to human action, will have an impact on many aspects of our environment. The nature of streamflow changes will depend on the magnitude and direction of the climate change. However, since the principal climatic factors that control streamflow are precipitation and evapotranspiration (which can be estimated from air temperature data), the sensitivity ofstreamflow to variations in climate can be studied through the use of plausible scenarios of climate change.
A simple water budget model was used to reconstruct streamflow from monthly temperature and precipitation data for locations within and immediately surrounding the Little Blue River basin in south-central Nebraska. Then, climate change scenarios corresponding to changes in monthly temperature of 1 °C and 3 °C and to differences in monthly precipitation of 10% and 20% were used to estimate the sensitivity of streamflow to climate change. Results of this procedure show the sensitivity of streamflow to climate variability. For example, a 20% increase in precipitation would more than double the average annual streamflow, while a 20% precipitation decrease would almost halve the average annual streamflow. The effects of temperature changes are similar, with a 3 °C increase resulting in an almost 60% decrease in streamflow, and a 3 °C decrease causing streamflow to increase by more than 80%. Scenarios with both temperature and precipitation changes can either enhance or nullify the effects of a single change.