{"pk":62436,"title":"Principal Hydrologic Responses to Climatic and Geologic Variability in the Sierra Nevada, California","subtitle":null,"abstract":"Sierra Nevada snowpack is a critical water source for California’s growing population and agricultural industry. However, because mountain winters and springs are warming, on average, precipitation as snowfall relative to rain is decreasing, and snowmelt is earlier. The changes are stronger at mid-elevations than at higher elevations. The result is that the water supply provided by snowpack is diminishing. In this paper, we describe principal hydrologic responses to climatic and spatial geologic variations as gleaned from a series of observations including snowpack, stream-flow, and bedrock geology. Our analysis focused on peak (maximum) and base (minimum) daily discharge of the annual snowmelt-driven hydrographs from 18 Sierra Nevada watersheds and 24 stream gage locations using standard correlation methods. Insights into the importance of the relative magnitudes of peak flow and soil water storage led us to develop a hydrologic classification of mountain watersheds based on runoff versus base flow as a percentage of peak flow. Our findings suggest that watersheds with a stronger base flow response store more soil water than watersheds with a stronger peak-flow response. Further, the influence of antecedent wet or dry years is greater in watersheds with high base flow, measured as a percentage of peak flow. The strong correlation between 1) the magnitude of peak flow, and 2) snow water equivalent can be used to predict peak flow weeks in advance. A weaker but similar correlation can be used to predict the magnitude of base flow months in advance. Most of the watersheds show a trend that peak flow is occurring earlier in the year.","language":"en","license":{"name":"Creative Commons Attribution 4.0","short_name":"CC BY 4.0","text":"Attribution — You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.\n\nNo additional restrictions — You may not apply legal terms or technological measures that legally restrict others from doing anything the license permits.","url":"https://creativecommons.org/licenses/by/4.0"},"keywords":[{"word":"Sierra Nevada"},{"word":"snowmelt"},{"word":"peak discharge"},{"word":"base flow prediction"},{"word":"climatic response"}],"section":"Research Article","is_remote":true,"remote_url":"https://escholarship.org/uc/item/2743f2n3","frozenauthors":[{"first_name":"David","middle_name":"H.","last_name":"Peterson","name_suffix":"","institution":"U.S. Geological Survey","department":""},{"first_name":"Iris","middle_name":"","last_name":"Stewart","name_suffix":"","institution":"Santa Clara University","department":""},{"first_name":"Fred","middle_name":"","last_name":"Murphy","name_suffix":"","institution":"U.S. Geological Survey","department":""}],"date_submitted":"2007-05-11T07:00:00Z","date_accepted":"2007-05-11T07:00:00Z","date_published":"2008-02-01T08:00:00Z","render_galley":null,"galleys":[{"label":"","type":"pdf","path":"https://journalpub.escholarship.org/jmie_sfews/article/62436/galley/48265/download/"}]}