This digital dataset contains the climate data used for the Lower Salinas Valley Hydrologic Models (Salinas Valley Integrated Hydrologic Model (SVIHM) and Salinas Valley Operational Model (SVOM)). The monthly climate data for the Lower Salinas Valley Hydrologic Models are based on the regional climate data for the Salinas Valley Hydrologic System [Hevesi and others, 2022]. To develop the monthly climate grids, the regional climate data were resampled to a monthly timescale and area weighted to the model grid. The climate data include spatially distributed monthly precipitation and potential evapotranspiration for the model grid for October 1967 to September 2018.

This digital dataset contains the climate data used for the Salinas Valley Hydrologic System, including the Salinas Valley Watershed Model (SVWM) and the Lower Salinas Valley Hydrologic Models (Salinas Valley Integrated Hydrologic Model (SVIHM) and Salinas Valley Operational Model (SVOM)). The climate data include spatially distributed daily precipitation, maximum and minimum air temperature, and potential evapotranspiration for the period from 10/1/1947 to 9/30/2023. This data set includes the following files: raster of the extent used in the Salinas Valley Hydrologic System; shapefiles of the input climate stations and daily gridded climate data for daily precipitation (PPT), maximum and minimum air temperature (TMN and TMX respectively), and potential evapotranspiration (PET).

This digital dataset contains the datasets related to agricultural and municipal water supply and groundwater in the Lower Salinas Valley Hydrologic Models (LSVHM), including the Salinas Valley Operational Model (SVOM) and the Salinas Valley Integrated Hydrologic Model (SVIHM). Groundwater inflow and outflow data include reported groundwater pumpage and groundwater elevations obtained for the period from October 1, 1967, to September 30, 2018. Groundwater pumpage in the Lower Salinas Valley Hydrologic Models is grouped into (1) pre-estimated and specified municipal and industrial (referred to as water supply) and (2) simulated pumpage from all irrigation wells used to supply water for irrigation (referred to as agricultural supply). Groundwater pumpage is provided in units of acre-feet per month for each water balance subregion (Henson and Jachens, 2022). Groundwater pumpage was defined by water supply wells and agricultural supply wells. Additionally, water levels from wells were used to evaluate groundwater levels in the simulation. To support the agricultural water demand and supply estimates, surface water diversions and non-routed delivery are included for the water-balance subregions (WBS) that receive surface water for irrigation. To support the evaluation of groundwater levels in the Lower Salinas Valley Hydrologic Models, this data release includes groundwater-level contour maps and groundwater level time series for wells used to define head-dependent flow boundaries in water balance subregions 5 and 6 in the northwestern coastal area in the Lower Salinas Valley Hydrologic Models. Water-level maps were provided by the Monterey County Water Resources Agency (MCWRA) for fall of 1994, 2003, and 2011 for a composite of shallow aquifers (<201 feet below land surface) and deep aquifers (>201 to 420 feet below land surface). These contours can be used for spatial comparison of the model-simulated groundwater values with observed data. Head-dependent flow boundaries were simulated using the General Head Boundary Package (GHB) of MODFLOW (Harbaugh, 2005) and are implemented to represent lateral groundwater underflow. Citations: Harbaugh, A.W., 2005. MODFLOW-2005, the U.S. Geological Survey modular ground-water model-the Ground-Water Flow Process: U.S. Geological Survey Techniques and Methods 6-A16, https://doi.org/10.3133/tm6A16. Henson, W.R., and Jachens, E.R., 2022, Lower Salinas Valley Hydrologic Models: Discretization Data: U.S. Geological Survey data release. https://doi.org/10.5066/P9850MAK.

This digital dataset contains the land use data used for the Salinas Valley Hydrologic Models (SVHM): the Salinas Valley Watershed Model (SVWM), the Salinas Valley Integrated Hydrologic Model (SVIHM), and Salinas Valley Operational Model (SVOM). Land use data were compiled from available state, local, and federal datasets. Available multi-year composite land use data were integrated with national scale land use and land cover data and supplemented and refined with information from the California Pesticide Use Reporting (CalPUR) database (California Department of Pesticide Regulation, 2024) to provide a comprehensive edge-to-edge land use map for each year. Native vegetation was defined using the National Land Cover Database (NLCD) (U.S. Geological Survey, 2000; U.S. Geological Survey, 2003; U.S. Geological Survey, 2011; U.S. Geological Survey, 2014; Dewitz, 2021) and intersected in a GIS with other available land use data. If available land use data for an irrigated crop was present where NLCD data showed a native land use cover class, the irrigated land area was preserved. There were 56 land use types developed to represent native vegetation, urban areas, and crops in the Salinas Valley. The land use types can be grouped into the four land use analysis categories based on the frequency with which crops may change (high frequency rotational, annually stable, multi-year) or as native or urban classes (native/urban). There is a climate gradient across the valley that could lead to differences in crop management and demands in the coastal and inland areas, for example, gradients in precipitation and PET. Additionally, coastal areas can have differences in fog occurrence and cloud cover relative to inland areas. Inland and coastal climate zones were used to support the delineation of different growth rates for the land use types. Of the 56 land use types, 40 were defined as irrigated land use with an inland and coastal sub-type. Discriminating crops between these regions and climate zones allows for the simulation of potential differences in climate, water demands, and crop management.

This dataset provides time series for the ungaged watershed inflows and associated inflow points for the Lower Salinas Valley Hydrologic Models (SVHM), including the Salinas Valley Integrated Hydrologic Model (SVIHM) and the Salinas Valley Operational Model (SVOM). Monthly outflows from watersheds that do not have gages that surround the Salinas River Valley are used in the Lower Salinas Valley Hydrologic models are provided by the Salinas Valley Watershed Model (SVWM) (Hevesi and others, 2025) for the period from October 1, 1967 to September 30, 2018. The streams and tributaries that are not gaged and that are outside the active area simulated in the Lower Salinas Valley Hydrologic Models are provided as basin-wide estimates. The catchments are described as part of the surface water dataset (Henson and others, 2022). The surface inflows provided by the watershed inflows are used as part of the boundary conditions applied at model cells at the interface between outside of the model domain and within the active model domain. This data release contains a time series of input inflows for the 180 ungaged watersheds.

This digital dataset contains the surface water data used for both the Salinas Valley Watershed Model (SVWM) and the Lower Salinas Valley Hydrologic Models (Salinas Valley Integrated Hydrologic Model (SVIHM) and Salinas Valley Operational Model (SVOM)). The surface water dataset includes two regions of the Salinas River Watershed; the upper region is primarily within San Luis Obispo County, California and lower region of the Salinas River Watershed is contained within Monterey County, California. Subcatchments within the Salinas River watershed were delineated using the U.S. Geological Survey (USGS) 10m digital elevation model (DEM), USGS National Hydrography Dataset Best Resolution (NHD) watershed boundaries, and the NHD stream data (U.S. Geological Survey, 2019). For each defined subcatchment, a pourpoint was defined that connects the watershed outflow to the tributary streams or ephemeral stream channels defined for the Salinas River in the lower and upper Salinas Valley Watershed. For the stream network of the lower Salinas River Watershed, NHD defined streams were used to initially define the network. The lower Salinas River Watershed stream network was refined to account for diversion canals and undefined ephemeral channels that drain into the Lower Salinas Valley in cooperation with Monterey County. For the lower Salinas Valley, the stream network and subcatchment data were defined simultaneously. For the upper Salinas Valley the pourpoints were defined based upon where previously defined subcatchments intersected with the stream network defined by the Paso Robles Basin Model (Fugro West, Inc and Cleath Associates, 2002; Fugro West, Inc, ETIC Engineering, Inc, and Cleath and Associates, 2005). The stream network spatial data were not provided from San Luis Obispo County as a vector shape, and the USGS did not develop the Paso Robles Basin Model (PRBM), therefore a shapefile of locations where the PRBM grid contained a stream reach was used as a proxy for linear features of the stream network in the upper Salinas River Watershed. This data set includes the following files: - Shapefiles for stream network, both lower and upper watersheds - Streamflow gage data and location - Ungaged tributary inflow points, both lower and upper watersheds

The Lower Salinas Valley Hydrologic Models’ discretization data includes a shapefile of the model domain and layers and a shapefile of the water balance subregions. The Lower Salinas Valley Hydrologic Models (LSVHM) include a historical model, the Salinas Valley Integrated Hydrologic Model (SVIHM) and a reservoir operations model, the Salinas Valley Operational Model (SVOM). While the Lower Salinas Valley Hydrologic Models have different purposes, they have the same model extent and many of the same input datasets, including the discretization data included in this data release. The model domain for the Lower Salinas Valley Hydrologic Models includes the Salinas Valley groundwater basin and extends offshore to include offshore aquifers to represent potential seawater intrusion. The aquifer system is bounded by faults and depositional or formational boundaries; Some of these faults cut across some of the aquifer layers, these faults in the interior of the model domain are simulated as potential hydrologic flow barriers. The model grid is uniform, where each grid cell is approximately 6.46 acres (530-by-530 ft). There are 976 rows, 272 columns, and 9 layers having a varying number of active cells in each layer. The 9 model layers correspond to locally defined hydrostratigraphic units that represent aquifer systems that are separated by confining units (Feeney and Rosenberg, 2003; Kennedy/Jenks Consultants, 2004; Brown and Caldwell, 2015; Sweetkind, 2023). . These include the saturated portions of the younger and older alluvium that represent the shallow aquifer that is underlain by the Salinas Valley Aquitard. These units overlie the Pressure 180-Foot Aquifer and the Pressure 180/400-Foot Aquitard, which in turn overlies the Pressure 400-Foot Aquifer, the underlying deep aquitard, and the basement bedrock of the Monterey Formation. The geologic units that comprise the aquifers and confining units above the Monterey Formation include the recent Alluvium, Aromas Formation, Paso Robles Formation, and Purisima Formation (Sweetkind, 2023). The top of the Lower Salinas Valley Hydrologic Models' is represented by the altitude of the land surface, but because hydrostratigraphic units are discontinuous across the study area, the uppermost active layer is a composite of model layers 1, 3, 5, 7, and 9. The following are brief descriptions of the layers: (1) the uppermost shallow Quaternary Alluvial aquifer, (2) the Salinas Valley Aquitard, (3 & 5) the Pressure 180-Foot Aquifer, (4 & 6) the 180/400-Foot Aquitard, (7) the Paso Robles Formation, (8) the Purisima Formation, and (9) the basement bedrock. Within the model domain, a mass balance is maintained for 31 water balance subregions (WBS). The delineation of the WBS is based on the management areas of the Monterey County Zone 2C jurisdictional region offshore regions, and areas outside of the Zone 2C jurisdictional region that are inside the active model domain that represents the groundwater basin (MCWRA, 2015; MCWRA, 2018). Citations: Brown and Caldwell. 2015. State of the Salinas River Groundwater Basin, Consultants report prepared for Monterey County Resources Management Agency, January 16, 2015, 240 p. https://www.co.monterey.ca.us/home/showpublisheddocument/19678/636232750207170000. Feeney, M. and Rosenberg, L., 2003, Deep Aquifer Investigation – Hydrogeologic Data Inventory, Review, Interpretation and Implications, Technical Memorandum to WRIME, Inc., 40 p. https://www.co.monterey.ca.us/home/showdocument?id=61923. Kennedy/Jenks Consultants, 2004, Hydrostratigraphic Analysis of the Northern Salinas Valley, Consultants report prepared for Monterey County Water Resources Agency, 14 May 2004, 112p., https://www.co.monterey.ca.us/home/showdocument?id=61922. Monterey County Water Resources Agency (MCWRA), 2015, Monterey County Water Resources Agency, https://digitalcommons.csumb.edu/hornbeck_cgb_6_a/21. Monterey County Water Resources Agency (MCWRA), 2016, Boundary of the Monterey County