Impact of weather modification and land cover change on streamflow

Shifts in the temporal and spatial distributions of water have resulted in a need to improve existing water management practices. In order to meet the growing demand for water, the Wyoming Weather Modification Program coordinated with the National Center for Atmospheric Research (NCAR) to evaluate cloud seeding operations for snowpack augmentation in the North Platte basin. There is a critical need to evaluate the impact of weather modification and quantify the increase in streamflow as a result of increase in snowpack. In this research, the Variable Infiltration Capacity (VIC) model is developed for the North Platte basin to understand and quantify its snowpack-streamflow relationship. The VIC model is calibrated and validated using the historical hydro-meteorological data of the basin. Figure 1 compares observed streamflow to the output of the calibrated VIC model that shows a reasonable match with RMS error of 0.0267 million acre-feet (MAF) and correlation of 0.89. The North Platte VIC model is forced under various land use change and weather modification what-if-scenarios to understand their impact on streamflow. Figure 2 illustrates the simulation of two land use change scenarios and shows that conversion of forests and woodlands to grassland in 1980 causes increase in the streamflow in following years. Similar simulations are performed by changing weather conditions (e.g., storm characteristics) over selected grid points. Simulation results are used to develop statistical relationships between snowpack and streamflow. The optimum relationships are developed and applied to quantify streamflow volume increase due to snowpack increase as a result of weather modification