The Upper Klamath Watershed lies between the Cascade Range and the Basin and Range Province in southern Oregon and northern California. Bedrock stratigraphy in the area includes volcanic deposits, volcanic ejecta, and fluviolacustrine deposits. This creates three general hydrologic layers: 1) Highly permeable basalt with an older depositional age serving as the principle aquifer, 2) fluvial deposits made up of tuff, shale, agglomerate, sandstone, and volcanic ash that are collectively known as the Yonna Formation and act as a groundwater cap, and 3) more recent eruptive volcanic deposits that overlie the aquifer. Little water is able to permeate through the upper volcanic deposit layers to the principle aquifers. Groundwater is able to move freely throughout the upper basin despite geologi