Culling, Daniel P. Larsen, Joshua D. Engott, John A. Seymour, Whitney A. Cromwell, Geoffrey 20250421 integrated model https://www.sciencebase.gov U.S. Geological Survey This is a U.S. Geological Survey model archive data release. The GSFLOW model (https://doi.org/10.3133/tm6D1) extension and future climate scenarios archived here are based on the historical GSFLOW model used to simulate the groundwater and surface-water resources of the San Antonio Creek Valley watershed, Santa Barbara County, California (Woolfenden and others, 2022). https://doi.org/10.5066/P1VGXVD3 Geoffrey Cromwell Daniel P. Culling Matthew Young Joshua D. Larsen 2025 Publication Basel, Switzerland MDPI In the San Antonio Creek Valley Watershed (SACVW) of Santa Barbara County, California, climatic conditions, surface-water diversions, and groundwater withdrawals potentially affect water availability, magnitude of streamflow in San Antonio Creek, and the extent and quality of protected species habitat in the Barka Slough wetland. Future climate in central California may have warmer and drier conditions and more variable precipitation (Flint and Flint, 2012). This may result in an increase in overall water demand from agricultural, military, and municipal entities in the SACVW. In cooperation with the Santa Barbara County Water Agency, the U.S. Geological Survey has developed a suite of future models that represent the SACVW hydrologic system. The previously published integrated hydrologic model of the SACVW (simulating water years 1948–2018; Woolfenden and others, 2022) was extended to include water years 2019–21, and then modified to simulate two versions for future years 2022–51. Two models simulating future years 2022–51 were constructed, each with different climate inputs: 1) a repeated historical climate (SACIMF.1), and 2) a warmer and wetter climate model-based input (SACIMF.2). SACIMF.1 repeats the climate input from 1990–2021 in reverse order to represent the future years, while SACIMF.2 model utilizes the 2070-centered Drier Extreme Warming climate change projection (2070 DEW; California Department of Water Resources, 2020). The model with 2070 DEW climate has warmer temperatures and an increase in average annual precipitation, driven by more frequent large precipitation events, relative to the historical climate. This data release includes these two future models referred to as the San Antonio Creek Integrated models - future 1 and 2 (SACIMF.1 and SACIMF.2). The SACIMF.1 and SACIMF.2 were developed as a tool to simulate the potential long-term effects of changing climatic conditions on 1) water availability, streamflow, groundwater flow, groundwater recharge and other hydrologic conditions throughout the SACVW, 2) groundwater discharge to San Antonio Creek in Barka Slough, and 3) streamflow, stream disconnection, and depth to groundwater as key habitat metrics for protected species in Barka Slough. This data release archives two integrated hydrologic model scenarios (the SACIMF.1 and SACIMF.2). The development of the historical model input and output files (water years 1948–2018) included in this data release are documented in a U.S. Geological Survey Scientific Investigations Report 2021-5139 (Woolfenden and others, 2022). The development of the extended and future model input and output files (water years 2019–21 and 2022–51, respectively) included in this data release are documented in an associated publication(Cromwell and others, 2025). Collectively, these simulations are used to evaluate the potential effects of future climate on water availability in the San Antonio Creek Valley Watershed (SACVW), Barka Slough, and the effects of changing hydrologic conditions on the extent and quality of protected species habitat in the Barka Slough wetland. 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 historical model documentation report (Woolfenden and others, 2022) and the associated extended and future model publication (Cromwell and others, 2025) 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 reports can be found in the ReadMe.txt ASCII file which can be downloaded as part of this data release. 19471001 20510930 publication date Complete Not planned -120.5379 -120.0920 34.8444 34.6866 ISO 19115 Topic Category geoscientificInformation inlandWaters environment USGS Thesaurus streamflow groundwater level modeling groundwater flow None GSFLOW future water availability groundwater pumping San Antonio Creek Valley watershed Barka Slough USGS Metadata Identifier USGS:66ce3e62d34e98e8a9244111 Geographic Names Information System California Santa Barbara County Los Alamos None. Please see ‘Distribution Information’ section for details. Acknowledgement of the U.S. Geological Survey would be appreciated in products derived from this data release. None. Users are advised to read the dataset's metadata thoroughly to understand appropriate use and data limitations. It is requested that the suggested citation for this USGS data release be included in any publications that reference or utilize these data. Daniel Culling U.S. Geological Survey mailing

4165 Spruance Road

San Diego CA 92101 USA 619-225-6111 dculling@usgs.gov https://www.sciencebase.gov/catalog/file/get/6314057ad34e36012efa2cac?name=SIR2021-5139Thumbnail.jpg Image of the model domain and active area of the model. jpg Santa Barbara County Water Agency, Vandenberg Space Force Base None Unclassified None The model may require at least 8 GB of RAM and was successfully run using GSFLOW v 2.1.0 (Markstrom and others, 2008) on a 64-bit Windows 10 Enterprise OS. Geoffrey Cromwell Jill N. Densmore Donald S. Sweetkind John A. Engott Whitney Seymour Joshua D. Larsen Christopher P. Ely 2022 Publication Scientific Investigations Report 2022-5001 Reston, VA, USA U.S. Geological Survey https://doi.org/10.3133/sir20225001 Steven L. Markstrom Richard G. Niswonger R. Steven Regan David E. Prudic Paul M. Barlow 2008 publication n/a US Geological Survey https://doi.org/10.3133/tm6D1 Linda R. Woolfenden John A. Engott Joshua Larsen Geoffrey Cromwell 2022 publication n/a US Geological Survey https://doi.org/10.3133/sir20215139 Geoffrey Cromwell Daniel P. Culling Matthew J. Young Joshua D. Larsen 2025 publication Water Lorraine E. Flint Alan L. Flint 2012 publication n/a US Geological Survey https://doi.org/10.3133/sir20125132 California Department of Water Resources 2020 publication https://data.ca.gov/dataset/2070-extreme-climate-change-scenarios-for-water-supply-planning A.W. Harbaugh 1990 publication n/a US Geological Survey https://doi.org/10.3133/ofr90392 Linda R Woolfenden 2022 dataset https://www.sciencebase.gov U.S. Geological Survey https://doi.org/10.5066/p960eok8 Geoffrey Cromwell Joshua Larsen Christopher Kohel Christopher Ely Donald S Sweetkind David O'Leary 2022 dataset https://www.sciencebase.gov U.S. Geological Survey https://doi.org/10.5066/p9ad7dl8 United States Geological Survey 2024 dataset https://www.sciencebase.gov U.S. Geological Survey https://doi.org/10.5066/f7p55kjn The historical model was calibrated through a combination of trial-and-error and the automated parameter-estimation method PEST++ (White and others, 2020). Transient hydraulic-head observations include 5,477 measurements that represent conditions during periods of groundwater pumping (water years 1948-2018). The 5,329 drawdown observations are based on the transient hydraulic heads and were calculated as the rise or decline in hydraulic head after the first observation. Streamflow observations include the 1,200 monthly mean streamflow values calculated from daily recorded and measured data for 5 streamgages. Other observations include a reported value for precipitation to evapotranspiration and reported annual pumping. Aquifer properties, streambed conductivity, unsaturated-zone parameters, and selected watershed properties were modified until a reasonable match between the measured data and simulated values was achieved. The extended model and future climate scenarios (water years 2019-2051) are based on the calibration of this historical model period. No formal logical accuracy tests were conducted Data set is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record and the associated model documentation reports (Woolfenden and others, 2022; Cromwell and others, 2025) for additional details. No formal positional accuracy tests were conducted No formal positional accuracy tests were conducted United States Geological Survey 1994 dataset https://www.sciencebase.gov U.S. Geological Survey https://doi.org/10.5066/f7p55kjn Digital and/or Hardcopy 20191001 20220930 observed NWIS Water data Jeremy T. White Randall J. Hunt Michael N. Fienen John E. Doherty 2020 publication n/a US Geological Survey https://doi.org/10.3133/tm7C26 Digital and/or Hardcopy 20200101 publication date PEST++ used to calibrate historical model The process used to develop, calibrate, and apply the historical model is fully described in the historical model documentation report (Woolfenden and others, 2022). The process used to develop the future model scenarios is fully described in the accompanying journal article (Cromwell and others, 2025) 2023 Raster Pixel NAD_1983_UTM_Zone_10N 0.9996 -123.0 0.0 500000.0 0.0 row and column 150.0 150.0 meters North American Vertical Datum of 1988 1.0 meters Attribute values SIR2021_5139.shp Attribute Table Table containing attribute information associated with the data set. Producer Defined FID Internal feature number. ESRI Sequential unique whole numbers that are automatically generated. Shape Feature geometry. ESRI Shape type. HRU_TYPE hydrologic response unit Producer Defined 0 1 Area Area of shape Producer Defined inactive inactive model area Producer defined active active model area Producer defined model.zip and output.zip All input and output files associated with this data release are described in detail in the top level ReadMe.txt. Further descriptions of input and output files can be found in the documentation for GSFLOW. Producer Defined Ag_wells_2016_corrected_100820.csv Comma Separated Value (CSV) file containing agricultural well data. Producer Defined Layer Model layer number Producer Defined 1 4 Row Model Row number Producer Defined 26 101 Col Model Column number Producer Defined 8 253 Max Q Maximum flow Producer Defined -7215.0 0.0 meters per day new num New well number Producer Defined 524 698 old num Old well number Producer Defined 449 605 Agwells_corrected_2019.shp Attribute Table Table containing attribute information associated with the data set. Producer Defined FID Internal feature number. ESRI Sequential unique whole numbers that are automatically generated. Shape Feature geometry. ESRI Shape type. FID_ point identification Producer Defined 0.0 156.0 Well_no well number Producer Defined NaN no data Producer defined 007N032W01B001S 009N034W36R1 DDLat latitude Producer Defined 0.0 34.817612 decimal degrees DDLong longitude Producer Defined -120.523222 0.0 decimal degrees row model row Producer Defined 26.0 101.0 col model column Producer Defined 8.0 253.0 layers model layer Producer Defined 3 layer 3 Producer defined 4 layer 4 Producer defined 2 layer 2 Producer defined 1 layer 1 Producer defined X longitude Producer Defined 726636.721242 763351.228859 Y latitude Producer Defined 3844575.0 3855824.99989 WellID Well number Producer Defined 449 605 SACGRID_landuse_011823.shp Attribute Table Table containing attribute information associated with the data set. Producer Defined FID Internal feature number. ESRI Sequential unique whole numbers that are automatically generated. Shape Feature geometry. ESRI Shape type. HRU_TYPE hydrologic response unit Producer Defined 0 1 HRU_ID hydrologic response unit ID Producer Defined 1 33356 DEM_ADJ digital elevation model gridded elevation Producer Defined 19.39 867.94 meters 2016Well well number for water year 2016 Producer Defined 0.0 605.0 2019Well Well number for water year 2019 Producer Defined -999 605 2016Ag Agricultural description for water year 2016 Producer Defined << empty cell >> no agricultural designation Producer defined <<empty cell>> no agricultural designation Producer defined Field Crops Field Crops Producer defined Vineyard Vineyard Producer defined Truck and Berry Crops Truck and Berry Crops Producer defined Subtropical Fruits Subtropical Fruits Producer defined Western Warm Temperature Row Crop Western Warm Temperature Row Crop Producer defined 2019Ag Agricultural description for water year 2019 Producer Defined << empty cell >> no agricultural designation Producer defined << empty cell >> no agricultural designation Producer defined Western Warm Temperate Row Crop Western Warm Temperate Row Crop Producer defined Western Warm Temperate Vineyard Western Warm Temperate Vineyard Producer defined Western Warm Temperate Bush fruit and berries Western Warm Temperate Bush fruit and berries Producer defined Western Warm Temperate Orchard Western Warm Temperate Orchard Producer defined Not Irrigated Not Irrigated Producer defined Truck and Berry Truck and Berry Producer defined LF_EVT Landfire existing vegetation type Producer Defined << empty cell >> no agricultural designation Producer defined << empty cell >> no existing vegetation type Producer defined Western Warm Temperate Row Crop Western Warm Temperate Row Crop Producer defined Western Warm Temperate Vineyard Western Warm Temperate Vineyard Producer defined Western Warm Temperate Bush fruit and berries Western Warm Temperate Bush fruit and berries Producer defined Western Warm Temperate Orchard Western Warm Temperate Orchard Producer defined LF_Code Landfire code. References can be found in the accompanying report. Producer Defined 0 6984 SACr_barka_slough_marshland.zblst.2.csv Comma Separated Value (CSV) file containing data. Zonebudget output file Producer Defined TOTIM Total Time Producer Defined 15.0 37986.0 days PERIOD stress period Producer Defined 1 1248 STEP time step Producer Defined 15 31 ZONE zone number Producer Defined 1 9 STORAGE Storage inflow Producer Defined 0.0 183742.3 cubic meters per day CONSTANT HEAD CONSTANT HEAD boundary inflow Producer Defined 0.0 0.0 cubic meters per day HEAD DEP BOUNDS HEAD DEPendent BOUNDary inflow Producer Defined 0.0 3280.819 cubic meters per day STREAM LEAKAGE STREAM LEAKAGE inflow Producer Defined 1.427854 130552.0 cubic meters per day UZF ET unsaturated zone (UZF) evapotranspiration (ET) inflow Producer Defined 0.0 0.0 cubic meters per day GW ET groundwater ET inflow Producer Defined 0.0 0.0 cubic meters per day UZF INFILTR. UZF infiltration (INFILTR) inflow Producer Defined 0.0 2312209.0 cubic meters per day UZF RECHARGE UZF RECHARGE inflow Producer Defined 0.0 113431.0 cubic meters per day SURFACE LEAKAGE SURFACE LEAKAGE inflow Producer Defined 0.0 0.0 cubic meters per day HORT+DUNN HORT+DUNN runoff inflow Producer Defined 0.0 10438.02 cubic meters per day STORAGE CHANGE STORAGE CHANGE inflow Producer Defined 1.526557e-16 2291303.0 cubic meters per day MNW2 multi-node well (MNW2) inflow Producer Defined 0.0 1054.188 cubic meters per day AG WE agricultural well (AG WE) inflow Producer Defined 0.0 0.0 cubic meters per day From Other Zones From Other Zones inflow Producer Defined 810.0317 15989.32 cubic meters per day Total IN Total INflow Producer Defined 1897.936 4795916.0 cubic meters per day STORAGE.1 Storage outflow Producer Defined 0.0 241321.1 cubic meters per day CONSTANT HEAD.1 CONSTANT HEAD boundary outflow Producer Defined 0.0 0.0 cubic meters per day HEAD DEP BOUNDS.1 Head dependent boundaries outflow Producer Defined 0.0 365.0872 cubic meters per day STREAM LEAKAGE.1 STREAM LEAKAGE outflow Producer Defined 0.0 1872.983 cubic meters per day UZF ET.1 UZF ET outflow Producer Defined 0.0 255373.1 cubic meters per day GW ET.1 GW ET outflow Producer Defined 0.0 36058.73 cubic meters per day UZF INFILTR..1 UZF INFILTRation outflow Producer Defined 0.0 0.0 cubic meters per day UZF RECHARGE.1 UZF RECHARGE outflow Producer Defined 0.0 0.0 cubic meters per day SURFACE LEAKAGE.1 SURFACE LEAKAGE outflow Producer Defined 0.0 12692.97 cubic meters per day HORT+DUNN.1 HORT+DUNN runoff outflow Producer Defined 0.0 0.0 cubic meters per day STORAGE CHANGE.1 STORAGE CHANGE outflow Producer Defined 9.508012e-09 275943.2 cubic meters per day MNW2.1 MNW2 outflow Producer Defined 0.0 23295.88 cubic meters per day AG WE.1 AG WE outflow Producer Defined 0.0 207777.4 cubic meters per day To Other Zones To Other Zones outflow Producer Defined 810.0317 15989.32 cubic meters per day Total Out Total Outflow Producer Defined 1911.427 658966.5 cubic meters per day IN-OUT Inflow - Outflow Producer Defined -530102.6 4610743.0 cubic meters per day Percent Error Percent Error Producer Defined -134.5728 185.1299 FROM ZONE 0 Inflow FROM ZONE 0 Producer Defined 0.0 0.0 cubic meters per day FROM ZONE 1 Inflow FROM ZONE 1 Producer Defined 0.0 15989.32 cubic meters per day FROM ZONE 9 Inflow FROM ZONE 9 Producer Defined 0.0 15174.26 cubic meters per day TO ZONE 0 Outflow TO ZONE 0 Producer Defined 0.0 0.0 cubic meters per day TO ZONE 1 Outflow TO ZONE 1 Producer Defined 0.0 15174.26 cubic meters per day TO ZONE 9 Outflow TO ZONE 9 Producer Defined 0.0 15989.32 cubic meters per day Unnamed: 42 null column Producer Defined << empty cell >> No Data Producer defined nan nan SACr_basin.zblst.2.csv Comma Separated Value (CSV) file containing data. Zonebudget output file with the same attributes as SACr_barka_slough_marshland.zblst.2.csv but using different zones. Producer Defined gsflow.csv Comma Separated Value (CSV) file containing data output from GSFLOW. Full documentation of fields and units can be found in the GSFLOW_Input_Instructions.v.2.1.0.pdf file from the GSFLOW release "doc" directory found online https://doi.org/10.3133/tm6D1 Producer Defined The following describes the location of files and directories described in this entity and attribute section: ./georef/SIR2021_5139.shp ./output/SACIMF.1_RRC/gsflow.csv and ./output/SACIMF.2_DEW/gsflow.csv, Guidance for GSFLOW output files can be downloaded from https://doi.org/10.3133/tm6D1 ./ancillary/Zonebudget/SACIMF.1/SACr_basin.zblst.2.csv and ./ancillary/Zonebudget/SACIMF.2/SACr_basin.zblst.2.csv ./ancillary/Zonebudget/SACIMF.1/SACr_barka_slough_marshland.zblst.2.csv and ./ancillary/Zonebudget/SACIMF.2/SACr_barka_slough_marshland.zblst.2.csv ./ancillary/LandUse/SACGRID_landuse_011823.shp ./ancillary/LandUse/Agwells_corrected_2019.shp ./ancillary/LandUse/Ag_wells_2016_corrected_100820.csv Further details of the GSFLOW and Zonebudget input and output files can be found in their release documentation: Markstrom, S.L., Niswonger, R.G., Regan, R.S., Prudic, D.E., and Barlow, P.M., 2008, GSFLOW-Coupled Ground-water and Surface-water FLOW model based on the integration of the Precipitation-Runoff Modeling System (PRMS) and the Modular Ground-Water Flow Model (MODFLOW-2005): U.S. Geological Survey Techniques and Methods 6-D1, 240 p., https://doi.org/10.3133/tm6D1 Harbaugh, A.W., 1990, A computer program for calculating subregional water budgets using results from the U.S. Geological Survey modular three-dimensional ground-water flow model: U.S. Geological Survey Open-File Report 90-392, 46 p., https://doi.org/10.3133/ofr90392 Culling, Daniel P., Larsen, Joshua D., Engott, John A., Seymour, Whitney A., and Cromwell, Geoffrey, 2025, GSFLOW model to extend the San Antonio Creek Integrated Model and simulate future climate scenarios, San Antonio Creek Valley watershed, Santa Barbara County, California: U.S. Geological Survey data release, https://doi.org/10.5066/P1VGXVD3 U.S. Geological Survey GS ScienceBase mailing address

Denver Federal Center, Building 810, Mail Stop 302

Denver CO 80225 United States 1-888-275-8747 sciencebase@usgs.gov The data have been approved for release by the U.S. Geological Survey (USGS). Although the data have been subjected to rigorous review and are substantially complete, the USGS reserves the right to revise the data pursuant to further analysis and review. Furthermore, the data are released on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from authorized or unauthorized use. Although the data, software, and related material have been processed successfully on a computer system at the USGS, no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty. The USGS or the U.S. Government shall not be held liable for improper or incorrect use of the data described and/or contained herein. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Digital Data https://doi.org/10.5066/P1VGXVD3 None 20250801 Daniel P Culling USGS - SOUTHWEST REGION Hydrologist mailing and physical

4165 Spruance Rd

San Diego CA 92101 (858) 637-6880 dculling@usgs.gov FGDC Content Standards for Digital Geospatial Metadata FGDC-STD-001-1998