The USGS Alaska Science Center seeks to provide financial assistance for research to quantify the hydrologic function - including collection, storage, and discharge of water- in different wetlands areas of the Mat-Su Valley. The proposed work would accomplish this primary objective through the use of detailed hydrologic modeling. Modeling work in this project would quantify storage and fluxes of water in different wetlands zones. Additional data collection may be necessary to improve model performance. The needs for additional data will be identified in the first phase of the project, conducted in federal fiscal year 2014. The U.S. Geological Survey developed a groundwater model for the Matanuska-Susitna Borough with funding from the State of Alaska, Department of Natural Resources and the Matanuska-Susitna Borough. Further refinement of that model is needed to identify important wetlands that contribute to base flows in area streams. Base flow is a critical component to ensuring sufficient stream habitat is present and adequate for salmon populations, other aquatic species as well as terrestrial species that depend on both salmon and riparian environments. Wetlands are thought to play a critical role in contributing to base flows based on work in other parts of Southcentral Alaska, particularly the Kenai Peninsula, where preliminary studies have shown that peatland-type wetlands can contribute as much as 50% of the base flow to streams.