Hydrogeologic framework of the Treasure Valley and surrounding area, Idaho and Oregon

Abstract

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Groundwater-flow model of the Treasure Valley, southwestern Idaho, 1986–2015

“…Hundreds of published and unpublished reports on various aspects of the geology and hydrology of the WSRP have been prepared by government agencies, universities, and consultants. Bartolino (2019a) contains a discussion of reports deemed most relevant to preparing the 3D HFM. Most relevant to the current report are eight prior groundwater-flow models of all or part of the WSRP.…”

“…The northern part of the study area is separated by an east-west line of uplands that forms the interfluve between the Boise River watershed to the south and the Payette River watershed to the north. The altitude generally ranges from about 4,810 ft at Prospect Peak along the north-central boundary down to 2,140 ft at the Snake River (Bartolino, 2019a).…”

“…and typically occurring in January (Western Regional Climate Center, 2019). A more complete discussion of the climate of the study area may be found in Bartolino (2019a). Bartolino (2019a, b) created a 3D HFM (fig.…”

“…1) is "the agricultural area that stretches west from Boise into Oregon" (U.S. Board on Geographic Names, 2019), although it is commonly referred to as "the lower Boise River watershed" or "the Boise River drainage basin downstream of Lucky Peak Lake"; it lies within the westernmost part of the western Snake River Plain (WSRP). Groundwater withdrawals provide most of the domestic and municipal water in the valley and surrounding area, except for 30 percent of Boise's municipal supply taken from the Boise River (Bartolino, 2019a).…”

“…In 2016, the U.S. Geological Survey (USGS), in cooperation with the Idaho Water Resource Board and the Idaho Department of Water Resources (IDWR), began a project to collect additional streamflow data (in the form of 10 new continuous streamgages and 3 additional synoptic streamflow-measurement sites) at 13 ditches and streams that serve as the primary outflow points for the expansive network of agricultural ditches and drains, develop a revised hydrogeologic framework, and create a groundwater-flow model of the Treasure Valley (Hundt, 2023). This is the third USGS report documenting the various components used to develop a groundwater-flow model: the first report described the project and summarized existing studies (Bartolino and Vincent, 2017), and the second report described the process used to build a three-dimensional hydrogeologic framework model (3D HFM) of the WSRP aquifer system (Bartolino, 2019a).…”