|2009 Portland GSA Annual Meeting (18-21 October 2009)|
|Paper No. 244-29|
|Presentation Time: 9:00 AM-6:00 PM|
DO REACH-SCALE GEOMORPHICALLY DEFINED PROCESS ZONES PREDICT SENSITIVITY OF CHANNEL SYSTEMS AND HYDROLOGIC PROCESSES IN THE MOUNTAINS OF THE CENTRAL GREAT BASIN?
LORD, Mark1, MILLER, Jerry1, GERMANOSKI, Dru2, VILLARROEL, Lionel3, TURY, Rachael1, WALSH, Danvey1, and CHAMBERS, Jeanne4, (1) Department of Geosciences & Natural Resources, Western Carolina University, Cullowhee, NC 28723, email@example.com, (2) Geology and Environmental Geosciences, Lafayette College, Easton, PA 18042, (3) Geosciences and Natural Resources, Western Carolina University, Cullowhee, NC 28723, (4) Rocky Mountain Research Station, USDA Forest Service, Reno, NV 89512|
Riparian corridors in the mountains of the central
Channel-slope systems in 7 basins, representing different geomorphic states, were mapped for 9 major units based on 1) valley form (hollow or valley), 2) presence or absence of a channel, and 3) material type (alluvium, colluvium, bedrock). In addition, non-channelized segments, common on alluvial/colluvial fans, were mapped because of the importance to sediment and hydrologic connectivity. Topographic cross sections, slopes, grain size, lithology, and hydrologic traits were determined for dozens of sites in all basins to characterize each map unit. Two subbasins were instrumented with hydrologic monitoring equipment to directly assess hydrologic processes and connectivity in relation to process zones.
Work is preliminary, but in basins analyzed unincised hollows and valleys are the most common process zone units by frequency and cumulative length. Percent connectedness of a basin is the area of the basin/subbasin with continuous channels that can contribute sediment and surface water to axial channels. At basin scale, connectedness varies from 74 to 83 % with higher percents in basins that have more axial channel incision. Groundwater and surface water traits show a general, but not exact, correspondence to process zones. Non-connected segments, pending channel formation by big events, block transport of surface water and sediment decreasing the likelihood of downstream channel change, but promote groundwater recharge important to sustaining riparian ecosystems. Further work will complete spatial and structural analysis of map units, and develop models that can, at least conceptually, predict reach and basin scale response for different magnitude events
2009 Portland GSA Annual Meeting (18-21 October 2009)
General Information for this Meeting
|Session No. 244--Booth# 70|
Oregon Convention Center: Hall A
9:00 AM-6:00 PM, Wednesday, 21 October 2009
Geological Society of America Abstracts with Programs, Vol. 41, No. 7, p. 624
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