A Hydrogeologic Framework for Understanding Local Groundwater Flow Dynamics in the Southeast Deschutes Basin, Oregon, USA

Abstract

Understanding local hydrogeology is important for the management of groundwater resources and the ecosystems that depend on them. The main objective of this study conducted in central Oregon, USA was to characterize the hydrogeologic framework of a part of the semiarid Upper Deschutes Basin. Information on local geology and hydrology was synthesized to construct a hydrogeologic framework and a conceptual model of groundwater movement in shallow and previously unmapped deeper aquifers. Study results show that local geology drives many of the surface water and groundwater connections that sustain groundwater-related ecosystems and ranching-related activities in the geographical area of interest. Also, the findings of this study suggest that ecohydrological investigations can be used to mitigate concerns regarding groundwater development. Likewise, newly-developed conceptual models of the hydrogeology of previously unstudied areas within a groundwater basin undergoing regulation offer opportunities to not only address concerns regarding integrated surface water–groundwater interactions but also provide supplemental sources of water for nearby areas undergoing groundwater depletion through proposed bulk water transfers.

Overstory–Understory Vegetation Cover and Soil Water Content Observations in Western Juniper Woodlands: A Paired Watershed Study in Central Oregon, USA

“…This study adds to the body of knowledge by providing a watershed-scale understanding of the long-term effects of juniper removal on soil water and vegetation cover in a semiarid woodland ecosystem in central Oregon, in the Great Basin region of the United States. Results from this and other recent research [25,53] we have conducted at this study site show there are significant ecologic and hydrologic benefits associated with western juniper control. However, it is also evident that juniper is reestablishing at a relatively rapid pace in the treated watershed.…”

The Seasonal Water Balance of Western-Juniper-Dominated and Big-Sagebrush-Dominated Watersheds

“…Clarno and John Day formations dominate the geology in this region, with alluvium in the valleys. The low permeability of the deeper geologic strata has resulted in transient unconfined shallow aquifers that primarily follow surface topography and that are recharged during the winter precipitation and spring snowmelt runoff seasons [52]. The topography of Mays WS and Jensen WS are similar and are characterized by a relatively low gradient landscape.…”

“…In many instances, seasonal precipitation or irrigation inputs percolating below the effective rooting zone contribute to the replenishment of the shallow aquifer [30,51]. Groundwater recharge can be influenced by geologic characteristics, such as the presence of fractured bedrock or basalt [30,52], and precipitation timing and quantity [53] or vegetation [54].…”

“…Research addressing the effects of woody vegetation on water yield in cool climates is limited. Only a few studies (see, for example, [30,52]) have addressed vegetation and groundwater relationships in sagebrush-and juniper-dominated landscapes. More studies focused on the linkages between seasonal winter precipitation and water distribution throughout the landscape are needed to enhance base knowledge of the biophysical mechanisms that influence surface water and groundwater connectivity in rangeland ecosystems.…”

Using an Open-Source Tool to Develop a Three-Dimensional Hydrogeologic Framework of the Kobo Valley, Ethiopia

“…Three-dimensional geological models can play a vital role in understanding the stratigraphic framework of aquifer systems and are used to create hydrogeologic representations of a groundwater flow system [18,19]. Three-dimensional geological models can also help estimate the geometry and related volumes of stratigraphic units or subregions delineated as aquifers or aquitards [20][21][22][23][24][25][26].…”