Modeling & Water Budget

The U.S. EPA VELMA model is regarded as one of the best watershed modeling programs because it models the interactions of multiple ecosystem parameters on a daily time scale. The SWRCB drainage area ratio model was used to scale the differences between the three watersheds as a result of differing watershed size. Finally, the Nash and Sutcliffe Efficiency coefficient (NSE), which is an important statistical tool that hydrologists use to assess the performance of their models, was used to improve results so that they more closely simulated discharge to approach observed discharge.

The California Department of Water Resources (DWR) has released the Handbook for Water Budget Development: With or Without Models. DWR developed the Water Budget Handbook to provide the California water resources community with a resource to help inform the development of water budgets for any geographic area and time period, using modeling, and non-modeling approaches alike. This handbook is not intended to be used as a prescriptive method of water budget analysis  but rather a tool and inventory of information to aid in development of water budgets