CWCB Water Availability Task Force: Monster snowpack across the northern basins, southern basins not so much

A picture named snowpackcolorado04152011

Below are my notes from Thursday’s meeting:

Flooding outlook

It’s too early in the season to know what to expect from the monster snowpack. The state is watching the Yampa, White and Upper Colorado rivers closely. Localized flooding is expected and could be exacerbated by precipitation events or warming temperatures shortening the runoff season. The large main stem reservoir operators are drawing down right now in anticipation of the above average streamflows expected across the northern part of the state.

The CWCB is watching streamflow gages around the state and has set alarms for 5 or 10 year flows for advance flood warning.

The state’s Flood DSS website startup is May 1. There is some information there now. Here’s the URL:

[Macintosh users: The viewer app doesn’t work in Safari. I hope the state fixes that.]

Report from the CWCB:

Veva DeHeza mentioned the drought workshops taking place over the first part of the summer:

At the CWCB meeting, May 17-18 in Durango, the board will consider, for the first time, a set of revised guidelines for approving municipal drought plans.

Another round of outreach is planned for phase one of the Colorado River Water Availability Study. Phase one of the study is not yet complete and phase two is on hold.

Report from the State Climatologist

Colorado had above average temperatures over most of the state in March. For the period of April 1-11 the northern mountains are doing very well with 1-2 in. of precipitation. Becky Smith reported above average precipitation for the Upper Colorado River. Fort Collins was near normal until March and has dropped since then. Boulder is showing below average precipitation for the water year.

Report from the Natural Resources Conservation Service

Snowpack/reservoir storage/streamflow forecast:

Yampa/White — snowpack 131% of average (the best since 1996 and second highest since the SNOTEL program began), this year has exceeded maximum values for the basin, streamflow forecast for the North Platte is 174% of average and the Yampa forecast is 157% of average.

Colorado — Snowpack is 131% of average, again the highest since 1996, reservoir storage is 113% of average.

South Platte — This is an interesting year for this basin. Echo Lake (Bear Creek watershed) is below average and the SNOTELS above Antero are all below average. Overall the basin is 120% of average and reservoir storage is 99% of average.

The forecasted streamflow for Clear Creek is 136% of average up from 121% of average last month. The streamflow forecast for the South Platte River is 112% of average and the forecast for the Poudre is 135% of average.

Gunnison — Snowpack is 114% of average, reservoir storage is 96% of average and inflows to Blue Mesa Reservoir are forecasted to be 111% of average.

San Miguel/Dolores/San Juan — Snowpack is 86% of average. Things have flattened down there with precipitation coming in at 94% of average — most of that due to a big storm in December. Without that storm things would now be very alarming. Reservoir storage is 105% of average. The streamflow forecast for inflows to McPhee Reservoir is 70% of average.

Rio Grande — The April 1 snowpack is 76% of average and reservoir storage 82% of average. The Sangre de Cristos are very dry. For example, the streamflow forecast for Culebra Creek is only 42% of average. That’s down from the forecast of 57% of average in March.

Arkansas — Snowpack is 103% of average but the number is misleading. The upper Ark valley is doing very well but the southern tributaries are very dry. Precipitation for the basin is 91% of average and reservoir storage is 90% of average. The streamflow forecast for the Arkansas River at Salida is 129% of average.

Long Term Weather Outlook

According to Klaus Wolter the current La Niña is the biggest event in 35 years. He forecasts a slight chance of above normal precipitation in May and June. The next week should be on the cool side helping to preserve the snowpack. There have been 3 dust events, “in the San Juans at least,” he said. Over the next two weeks he is forecasting that the northern mountains could get 1 – 2 inches of moisture and if those storms hit the plains some areas could see one half – 1 inch. The next two weeks may be wetter than normal.

Other task force reports

The representative from the Ag Task Force said, “Conditions have gone from bad to worse.” There are record low numbers of cattle in Colorado due to sell-offs of herds during the 2002 — numbers have not recovered and won’t this year. 60% of pasture and rangeland is in poor to very poor condition. 80% of the winter wheat crop is poor to very poor.

The representative from Colorado Springs Utilities said that there is virtually no snowpack above their South Slope collection system.

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