Looking at Environmental Flows in the upper Colorado River Basin - PowerPoint PPT Presentation

Looking at Environmental Flows in the upper Colorado River Basin Adam Csank Department of Geography University of Nevada-Reno

They are particularly interested in projected changes in streamflow timing. Interested in learning how often their low flow thresholds are met. Interested in changes in the percentage of wet vs dry years.

Indicators of Hydrologic Alteration

Sojka et al. (2016)

Parameter Group 1 Magnitude of monthly water conditions mean or median flow for each month

Parameter Group 2 Magnitude and duration of extreme water conditions

Parameter Group 3 Timing of extreme water conditions Date of each annual maximum & minimum Number and duration of low pulses Number and duration of high pulses

Parameter Group 4 Rate and frequency of water condition changes Rise rates, fall rates & number of hydrologic reversals. https://waterdata.usgs.gov/usa/nwis/uv?09058000

Test Case: Yampa River https://www.oars.com/adventures/yampa-river-rafting/

Projected Changes in streamflow timing

How often are low flow thresholds met?

Threshold target Yampa River Between 93 and 135 cfs (ideally >120) during the baseflow period (August- October)

Yampa River days with discharge below threshold <120 cfs <93 90 150000 80 70 60 100000 number of days 50 40 50000 30 20 10 0

August September October 100000 90000 80000 70000 60000 50000 40000 30000 20000 10000 0

Yampa River Baseflow recon obs 10 per. Mov. Avg. (recon) 10 per. Mov. Avg. (obs) 250000 200000 Aug-Oct Streamflow (acre-ft) 150000 100000 50000 0 1550 1600 1650 1700 1750 1800 1850 1900 1950 2000

Which (if any) of the IHA might be useful to you?

Any recommendations for other directions or things to look at?

Ecological Limits of Hydrologic Alteration (ELOHA) Scientific Process Hydrologic Foundation River Classification Baseline Hydrologic Geomorphic Hydrographs River Type Classification sub-classification Flow data and modeling Flow Alteration Measures Developed Analysis of Flow of Flow Hydrographs Alteration Alteration Monitoring Flow-Ecology Relationships Flow Alteration- Flow-Ecology Ecological Ecological response hypotheses for Data for each relationships for each each river type analysis node river type Social/Management Process Acceptable Environmental Societal Values and Implementation Ecological Flow Standards Management Needs Conditions