No Snow_No Flow; The 2015 Snow Drought in the Oregon Cascades; Raw and Modeled Hydrologic and Geomorphic Data
|Authors:||Laura Hempel Sarah Lewis|
|Resource type:||Composite Resource|
|Storage:||The size of this resource is 29.9 MB|
|Created:||Aug 21, 2018 at 7 p.m.|
|Last updated:|| Sep 06, 2018 at 6:48 p.m.
|Citation:||See how to cite this resource|
|Content types:||Single File Content Geographic Feature Content|
Hydrologic extremes, such as drought, offer an exceptional opportunity to explore how runoff generation mechanisms and stream networks respond to changing precipitation regimes. The winter of 2014-2015 was the warmest on record in western Oregon, US, with record low snowpacks, and was followed by an anomalously warm, dry spring, resulting in historically low streamflows. But a year like 2015 is more than an outlier meteorological year. It provides a unique opportunity to test fundamental hypotheses for how montane hydrologic systems will respond to anticipated changes in amount and timing of recharge. In particular, the volcanic Cascade Mountains represent a “landscape laboratory” comprised of two distinct runoff regimes: the surface-flow dominated Western Cascade watersheds, with flashy streamflow regimes, rapid baseflow recession, and very low summer flows; and (b) the spring-fed High Cascade watersheds, with a slow-responding streamflow regime, and a long and sustained baseflow recession that maintains late summer streamflow through deep-groundwater contributions to high volume, coldwater springs.
We hypothesize that stream network response to the extremely low snowpack and subsequent recharge varies sharply in these two regions. In surface flow dominated streams, the location of channel heads can migrate downstream, contracting the network longitudinally; the wetted channel width and depth contract laterally as summer recession proceeds and flows diminish. In contrast, in spring-fed streams, channel heads “jump” to the next downstream spring when upper basin spring flow diminishes to zero. Downstream of flowing springs, wetted channel width and depth contract laterally as flows recede.
To test these hypotheses, we conducted a field campaign to measure changing discharge, hydraulic geometry, and channel head location in both types of watersheds throughout the summer and early fall. Multiple cross-section sites were established on 6 streams representing both flow regime types on either side of the Cascade crest. In addition we took Isotopic water samples to determine recharge elevations of receding streams. Taken together these measurements reveal the processes by which drainage networks contract as flows diminish – a fundamental property of montane stream systems both now and in the future.
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|xml metadata||Laura Hempel; Sarah Lewis; 20140930-20150501; Other- Anne Nolin; Gordon Grant; Mohammad Safeeq; Sarah L Lewis; Jason B Dunham; Marshall Gannett; Christina Tague; Karl Morgenstern; Mark Kramer; Brian Staab. Climate Change and Peak Flows: Knowledge-to-Action to Help Managers Address Impacts on Streamflow Dynamics and Aquatic Habitat. Corvallis, OR; DOI Northwest Climate Science Center; observed; Complete; No plans to update; measured discharge; streamflow; Regional Hydro-Ecologic Simulation System (RHESSys); Anderson Creek; Boulder Creek; Canyon Creek; Jack Creek; Users are advised to read the data set's metadata thoroughly to understand appropriate use and data limitations.; Sarah Lewis, College of Earth, Ocean, and Atmospheric Sciences, Oregon State University mailing address 3200 SW Jefferson Way Corvallis OR 97331 USA; firstname.lastname@example.org; No form attribute accuracy tests were conducted, or is not applicable.; No formal logical accuracy tests were conducted.; Data set is considered complete for the information presented, as described in the abstract.; A formal accuracy assessment of the horizontal positional information in the data set has not been conducted.; A formal accuracy assessment of the vertical positional information in the data set has either not been conducted, or is not applicable.; Anne Nolin Oregon State University mailing address Wilkinson 120 Oregon State University Corvallis OR 97333 USA 541-737-8051 email@example.com; FGDC Content Standard for Digital Geospatial Metadata; FGDC-STD-001-1998|
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