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Lumped parameter models of groundwater age, Spanish Valley Watershed, Grand and San Juan Counties, Utah

Metadata Updated: October 26, 2023

This data release documents two Microsoft Excel tables; one contains data for understanding groundwater ages in the Spanish Valley watershed, and one that describe the data fields. Mean ages and age distributions from 19 groundwater samples were estimated in support of an evaluation of the groundwater resources of the Spanish Valley watershed (Masbruch and others, 2019). Individual groundwater well and spring vulnerability to land-surface contamination and changes in hydraulic conditions (for example, water extraction or reduced recharge) can be assessed using environmental tracer-based groundwater age. The detailed interpretation of groundwater age reported here supplements the apparent tracer ages of Masbruch and others (2019). Multiple age tracers sampled in groundwater were fit using TracerLPM (Jurgens and others, 2012), with working knowledge of the well dimensions, hydrogeology, and geochemistry, to assign a unique age distribution. The age distributions describes the relative contributions of flow-paths of differing age and the extent of flow-path mixing in the sample. Concentrations of tritium (3H), tritiogenic-He (3Hetrit), chlorofluorocarbons (CFC-11, -12, -113), sulphur hexafloride (SF6), and geochemically corrected carbon-14 (14C) were fit by optimizing age distribution parameters. Details of 3Hetrit calculation, 14C geochemical correction, and noble gas based estimates of conditions which were used to correct CFCs and SF6 are described in Masbruch and others (2019). Lumped parameter models (LPM) are described for each sample by the mean age, LPM name, model parameters, and in the the case of binary mixing models (BMM) the mixing fraction and the mean age of the old component. Final mean age for BMMs is calculated as (Mean Age 1 * Fraction) + (Mean Age 2 * (1 – Fraction)).

Access & Use Information

Public: This dataset is intended for public access and use. License: No license information was provided. If this work was prepared by an officer or employee of the United States government as part of that person's official duties it is considered a U.S. Government Work.

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Metadata Created Date June 1, 2023
Metadata Updated Date October 26, 2023

Metadata Source

Harvested from DOI EDI

Additional Metadata

Resource Type Dataset
Metadata Created Date June 1, 2023
Metadata Updated Date October 26, 2023
Publisher U.S. Geological Survey
Identifier USGS:5d5f13e3e4b01d82ce984d40
Data Last Modified 20200827
Category geospatial
Public Access Level public
Bureau Code 010:12
Metadata Context
Metadata Catalog ID
Schema Version
Catalog Describedby
Harvest Object Id 009d0b42-a0a5-44a7-898d-feeab71d74f7
Harvest Source Id 52bfcc16-6e15-478f-809a-b1bc76f1aeda
Harvest Source Title DOI EDI
Metadata Type geospatial
Old Spatial -109.6106,38.2684,-109.0887,38.6179
Publisher Hierarchy White House > U.S. Department of the Interior > U.S. Geological Survey
Source Datajson Identifier True
Source Hash 4a5d7913e027829930fcebc2bd8a3bf13e30a8b480b4a2f766d0bfc82e6a9fbd
Source Schema Version 1.1
Spatial {"type": "Polygon", "coordinates": -109.6106, 38.2684, -109.6106, 38.6179, -109.0887, 38.6179, -109.0887, 38.2684, -109.6106, 38.2684}

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