MMODFLOW-OWHM used to characterize the flow system of the Petaluma River Watershed, Sonoma County, California

The Petaluma Valley integrated hydrologic model (PVIHM) was developed by the U.S. Geological Survey (USGS) in cooperation with the Sonoma County Water Agency and the City of Petaluma. The PVIHM simulates the 99,000-acre Petaluma valley watershed and includes 54,000 acres where groundwater flow is active. The model simulates 56 years of historical hydrology (water years 1960–2015) that includes a range of wet and dry climatic conditions. The model incorporates data collected from local (Sonoma County Water Agency and City of Petaluma), State, and Federal sources. The PVIHM is an integrated hydrologic model that simulates groundwater-flow, surface-water flow, and land-surface process systems in a single model using MODFLOW-OWHM. The model was calibrated using observed groundwater altitudes from 41 groundwater monitoring wells and measured streamflow data from 3 USGS streamflow gages. The model generates monthly water budgets for water use, groundwater flow, and streamflow for water years 1960–2015 as well as groundwater altitude hydrographs, simulated streamflow hydrographs, and maps of simulated groundwater altitude. This USGS data release contains all of the input and output files for the PVIHM model, which are described in the associated Scientific Investigation Report (https://doi.org/10.3133/sir20225009).

The Petaluma Valley Integrated Hydrologic Model (PVIHM) provides a tool that local water managers, such as the Petaluma Valley Groundwater Sustainability Agency (GSA), Sonoma County Water Agency (SCWA), and the city of Petaluma, can use to evaluate groundwater sustainability. The PVIHM simulates groundwater altitudes, groundwater storage, and groundwater and surface-water exchange, which are three of the six criteria used to evaluate groundwater sustainability under the Sustainable Groundwater Management Act (SGMA). Model-simulated scenarios can evaluate natural changes, such as the hydrologic effects of historical and future climate scenarios. In addition, model simulations can be used to evaluate effects of management actions, such as water conservation; enhanced recharge projects; and the conjunctive use of surface water, recycled water, and groundwater. This USGS data release contains all of the input and output files for the PVIHM model, which are described in the associated Scientific Investigation Report (https://doi.org/10.3133/sir20225009).

Support is provided for correcting errors in the data release and clarification of the modeling conducted by the U.S. Geological Survey. Users are encouraged to review the model documentation report (https://doi.org/10.3133/sir20225009) to understand the purpose, construction, and limitations of this model. The model will run successfully only if the original directory structure is correctly restored. The model archive is broken into several pieces to reduce the likelihood of download timeouts. Instructions for reconstructing the original directory structure and running the model included in this data release and described in the model documentation report can be found in the readme.txt ASCII file which can be downloaded as part of this data release.