Groundwater Model Coupling to Reclamation Surface Water Models
Reclamation currently has a suite of surface water numerical models. Reclamation's one-dimensional numerical hydraulics and sediment transport model, SRH-1D, and two-dimensional numerical hydraulics and sediment transport model, SRH-2D, both have extensive capabilities in predicting surface water properties and interactions in rivers, reservoirs, canals, and other hydraulic features. These surface water numerical models, however, do not address the important groundwater and surface water interactions.
This scoping proposal addresses the following question:
How can we improve Reclamation's capability in numerically modeling the interaction between groundwater and surface water resources for various Mission related needs and goals?
Need and Benefit
Reclamation is responsible for the combined effort of meeting water delivery and habitat requirements. In order to meet these needs, several purposes exist for improving the modeling of the interaction between groundwater and surface water resources to provide more benefit to these needs.
Example needs include:
1. An understanding of the importance of hyporheic flow in stream channels, which is the exchange between groundwater and surface water in stream channels. Hyporheic zones are significant in the dynamics of nutrients within the stream-catchment system (Bencala, 2005). For example, the exchange of nutrients due to hyporheic flow in alluvial gravels is important for the survival of salmon eggs (Malcom et al, 2003). Consideration of salmon egg survival is directly applicable to the improvement of the egg-to-smolt survival as part of Reclamation designing and improving habitat conditions for ESA listed Salmonid and Steelheed species as part of the FCRPS Biological Opinion.
2. Quantifying the amount of surface water seepage from rivers, reservoirs, or canals into groundwater features (e.g. shallow or deep aquifers) is necessary to identify methods to improve water delivery and/or endangered species habitat requirements.
3. The ability to describe or quantify the interaction of surface water and groundwater within alluvial fans reduces the uncertainty in designing infrastructure and/or modifications within these highly dynamic systems.
Current methods to couple groundwater and surface water models ignore many two-dimensional surface flow effects and are not able to represent complex stream geometries adequately (see http://water.usgs.gov/ogw/modflow/). Further research on coupling the groundwater and surface water to resolve smaller scale features of the interactions is necessary.
Contact the Principal Investigator for information about partners.
Bureau of Reclamation Review
The following documents were reviewed by experts in fields relating to this project's study and findings. The results were determined to be achieved using valid means.
Groundwater Model Coupling to Reclamation Surface Water Models (final, PDF,
By Sean Kimbrel
Publication completed on September 30, 2015