Brown, R.D. Coplen, T.B. Reid, L.T. 20250509 comma separated values https://doi.org/10.5066/P1STRX3R In this data release, hydrogen-2 and oxygen-18 isotope ratios are presented for 158 unique sites in central and eastern Washington. There are 16 unique surface water sites with a total of 140 samples, and 142 groundwater sites with a total of 167 samples. Sample dates range from February 1993 to February 2021. Stable isotope analysis of water utilizes slight differences in the mass of water molecules due to naturally occurring stable isotopes of oxygen and hydrogen replacing the lighter and more common oxygen-16 and hydrogen-1. These differences in water molecule mass influence behavior during physical processes within the hydrologic cycle, such as evaporation and condensation. These mass differences lead to isotopic fractionation, where the lighter isotopes (for example: oxygen-16 and hydrogen-1) are preferentially enriched in the vapor phase, while the heavier isotopes (for example: oxygen-18 and hydrogen-2) are enriched in the liquid phase. The extent of fractionation is controlled by local factors such as temperature, relative humidity, and distance from the ocean which, combined, create an isotopic signature. Measuring these variations in isotopic ratios caused by local processes can be valuable for identifying groundwater sources and understanding hydrologic connectivity and flow paths in regional systems (Clark and Fritz, 1997). Stable isotopes of water (hydrogen-2 and oxygen-18) are particularly useful as groundwater tracers because they are part of the water molecule and move unhindered within the aquifer matrix. In addition to conservative transport, hydrogen-2 and oxygen-18 mix conservatively and can be used to assess mixture ratios of water parcels from distinct sources. References cited: Clark, I.D., and Fritz, P., 1997, Environmental Isotopes in . CRC Press, 342p, https://doi.org/10.1201/9781482242911 Data was collected as a part of a larger national effort to characterize water isotopes in surface and groundwater. This data release, which is a subset of the larger unpublished dataset, supports the SIR titled, "Source of groundwater discharging from Rocky Ford Springs, Grant County Washington." This SIR discusses potential groundwater sources for Rocky Ford Springs based on stable water isotopes. 19930207 20210227 ground condition Complete None planned A Region in central and eastern Washington state, extending from the eastern slope of the Cascades to the Idaho border -120.3029 -117.0352 47.8714 46.2540 ISO 19115 Topic Category inlandWaters USGS Thesaurus hydrology isotopic analysis light stable isotope analysis groundwater surface water (non-marine) climatology meteorology atmospheric and climatic processes USGS Metadata Identifier USGS:6788363dd34e60ddd4de2c19 None Climatology Meteorology None. Please see 'Distribution Info' for details. None. Users are advised to read the dataset's metadata thoroughly to understand appropriate use and data limitations. Reid D Brown USGS - NW-PACIFIC ISLAND REG Hydrologist mailing and physical

WA WSC,Kress/PAyless Building

Tacoma WA 98402 253-552-1606 rdbrown@usgs.gov Authors and reviewers reviewed the data to ensure values fell within expected ranges. Most values fell within expected ranges, those that did not were flagged. All tables were checked for duplicate or omitted data. 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 for additional details. No formal horizontal accuracy tests were conducted. No formal vertical accuracy tests were conducted. Samples were analyzed for stable hydrogen and oxygen isotopic compositions at the Reston Stable Isotope Laboratory of the United States Geological Survey in Reston, VA. Hydrogen and oxygen isotopic results are reported in per mil relative to VSMOW (Vienna Standard Mean Ocean Water) and normalized (Coplen, 1994) on scales such that the hydrogen and oxygen isotopic values of SLAP (Standard Light Antarctic Precipitation) are -428 per mil and -55.5 per mill, respectively. The 2-sigma uncertainties of hydrogen and oxygen isotopic results are 2 per mil and 0.2 per mil, respectively. This means that if the same sample were resubmitted for isotopic analysis, the newly measured value would lie within the uncertainty bounds 95 percent of the time. Reference cited: Coplen, T. B., 1994. Reporting of Stable Hydrogen, Carbon, and Oxygen Isotopic Abundances, Pure and Applied Chemistry, v. 66, p. 273-276. 2021 Tyler B Coplen U.S. Geological Survey, WATER Director, Reston Stable Isotope Laboratory Mailing address

Mail Stop 431, 12201 Sunrise Valley Dr

Reston VA 20192 US 703-648-5862 703-648-5832 tbcoplen@usgs.gov Central_WA_SW_GW_Stable_Isotope_Data.csv Comma Separated Value (CSV) file containing data. This data file contains the stable hydrogen and oxygen isotope data measured at each of the sites. Some sites have multiple site visits. Producer Defined FieldID Common Name used on field sheets Producer Defined alphanumeric text d2H Stable hydrogen isotope-delta value of the sample relative to Vienna Standard Mean Ocean Water (VSMOW). Producer Defined -134.5 -78.2 per mil d18O Stable oxygen isotope-delta value of the sample relative to Vienna Standard Mean Ocean Water (VSMOW). Producer Defined -17.08 -6.69 per mil Medium_Code Sample Medium Identifier per USGS: https://help.waterdata.usgs.gov/code/medium_cd_query?fmt=html USGS 9 Legacy Surface Water USGS WS Surface Water USGS 6 Legacy Groundwater USGS WG Groundwater USGS SiteName Descriptive name of sample location. For wells that are registered with Washington Department of Ecology those IDs are used. Producer Defined alphanumeric text SiteNumber Site ID numbers for each site. The ID numbers are two different lengths: 8 numbers signify Surface water Sites (WS) and 15 numbers signify Groundwater (WG) Producer Defined Numeric Text CountyCode Numeric County Code for county site is located in https://help.waterdata.usgs.gov/code/county_query?fmt=rdb&inline=true USGS Defined Numeric Text 001 Adams County 003 Asotin County 005 Benton County 007 Chelan County 009 Clallam County 011 Clark County 013 Columbia County 015 Cowlitz County 017 Douglas County 019 Ferry County 021 Franklin County 023 Garfield County 025 Grant County 027 Grays Harbor County 029 Island County 031 Jefferson County 033 King County 035 Kitsap County 037 Kittitas County 039 Klickitat County 041 Lewis County 043 Lincoln County 045 Mason County 047 Okanogan County 049 Pacific County 051 Pend Oreille County 053 Pierce County 055 San Juan County 057 Skagit County 059 Skamania County 061 Snohomish County 063 Spokane County 065 Stevens County 067 Thurston County 069 Wahkiakum County 071 Walla Walla County 073 Whatcom County 075 Whitman County 077 Yakima County StateCode Numeric State Code for state site is located in https://www2.census.gov/geo/docs/reference/state.txt USGS Defined Numeric text 53 = WA Latitude Decimal Degree latitude for site location USGS Defined << empty cell >> No Data Producer defined 46.25396111 47.87141667 decimal degree Longitude Decimal Degree longitude for site location USGS Defined << empty cell >> No Data Producer defined -120.3029278 -117.0351528 decimal degree str_LatLongAccuracy Accuracy code for lat/long USGS << empty cell >> No Data Producer defined S Accurate to + or - 1 sec. Producer defined F Accurate to + or - 5 sec. Producer defined Collection Date and time sample was collected Producer Defined << empty cell >> No Data Producer defined date and time of sample collection Elevation Elevation of site. Units defined in LengthUnit column. Can be either meter or feet. Producer Defined << empty cell >> No Data Producer defined 352.0268211 2740.0 meter or feet LengthUnit Units for the Elevation column. m = meter, f = feet Producer Defined << empty cell >> No Data Producer defined f feet Producer defined m meter Producer defined U.S. Geological Survey - ScienceBase mailing address

Denver Federal Center

Building 810

Mail Stop 302

Denver CO 80225 United States 1-888-275-8747 sciencebase@usgs.gov Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (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. Digital Data https://doi.org/10.5066/P1STRX3R None 20250818 Reid Brown U.S. Geological Survey, WATER Hydrologist mailing and physical

934 Broadway

STE #300

Tacoma WA 98402 USA 259-365-8275 rdbrown@usgs.gov FGDC Biological Data Profile of the Content Standard for Digital Geospatial Metadata FGDC-STD-001.1-1999