Submitted by: Jennifer Johnson_1, Bureau of Reclamation, PN-6216, 208-378-5225, jmjohnson@pn.usbr.gov
Proposal ID: 60
| Title |
| Development of a multi-aquifer hydrologic modeling package to support Reclamation water use planning in rural/urban landscapes. |
| State the Problem. How Do Your Research Outputs Contribute to Achieving Reclamation's Mission, and The S&T Program Mission and Performance Measures? | Groundwater hydrologists use analytic element method (AEM) models and finite-difference (FD) models to answer hydrologic questions about changes in land use practices. AEM models are better suited to answer local scale questions while FD models are often used to answer regional scale questions. Both model types require large amounts of data and can demand significant amounts of time to pre- and post-process the model data. Presently, a public-domain hydrologic modeling package that combines a multi-layer analytic element method (AEM) model, a finite-difference model and a data processing tool does not exist. The purpose of this proposal is to create just such a software package. AEM models are computer programs that can be used to simulate the interactions between features, such as streams and wells, and the underlying aquifer (i.e. groundwater/surface water interactions). Single layer AEM models have been used by groundwater hydrologists to investigate many situations including: the effects of pumping on surrounding canals and reservoirs, the interactions between the rivers and nearby canals, and the implications of removing a portion of a canal. While these single layer models provide a useful preliminary solution to the problem, they are not entirely accurate in all cases because many aquifers contain more than one aquifer layer. To be more accurate in these studies, it is necessary to use a multi-layer AEM model. TimML is a public-domain multi-layer AEM model. Recent TimML investigations by Reclamation groundwater hydrologists include estimating leakage from dams and investigating well interactions in multi-layered systems. FD models are computer programs that provide a numerical solution to general equation for groundwater flow. FD models are fundamentally different from AEM models because FD model resolution is limited by a defined grid resolution. On the other hand, AEM model resolution is limited by the distance of one element to another and the resolution of the input data. The most commonly used and most trusted FD model is MODFLOW (developed by USGS). MODFLOW has been in use for many years and has been used in numerous Reclamation applications. ArcGIS is a geographical information system that can be used to organize and view spatially referenced data. Many groundwater hydrologists use ArcGIS to organize and process groundwater data, including high resolution elevation data such as green LiDAR. Separately, AEM and FD models provide answers to some conjunctive water management questions. However, combining the capability of these models would provide a powerful decision-making tool for groundwater hydrologists and water managers. |