Water situation: spring-like conditions, storage still good
February 9, 2018
Ranchers and land managers are already having to deal with spring-like conditions, according to the National Resources Conservation Service monthly report covering the water supply outlook for Nevada it issued for February on Friday.
In its February report for the first time, the NRCS report included information on rangeland conditions for ranchers and land managers to use in such areas as deciding livestock grazing. The report also provides a preliminary glimpse of what wildfire conditions could be as plants such as cheatgrass already began to grow in January.
The report, though, also continued to state water storage for the most part should be adequate to mitigate summer drought concerns. It also stated much of the state had its warmest fall in more than 120 years.
Statewide, this past fall was one of the driest and warmest on record, the report stated. The southern and central portion of the state had the warmest fall since 1895. Little to no measurable precipitation from Oct. 1-Dec. 31 was recorded in these areas.
Feb. 1 snow cover is minimal on Nevada's lower elevation rangelands, the report said. "This is of concern because seasonal snow cover replenishes soil moisture and provides water for plant growth," the report stated. "Plant growth has started across the state at low to mid-elevations. Annual non-native plants, such as cheatgrass, red brome, bur buttercup and mustards began growth in January. Cool-season perennial grasses, such as Sandberg bluegrass and crested wheatgrass have also begun green-up."
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February snowpack percentages are 26-50 percent of median across most of the region, the report stated. The report also stated the area is now facing conditions similar to the drought years of 2012, 2014 and 2015. In the Lake Tahoe, Truckee, Carson and Walker basins, current snow amounts are slightly better than 2015, while for the Humboldt Basin and Eastern Nevada there's less snow than 2015. SNOTEL data indicates the Upper Humboldt has its lowest Feb. 1 snowpack since the stations were installed in 1979. The Lower Humboldt is fourth lowest and Eastern Nevada is third lowest. Based on history, other years with snowpacks this low on Feb. 1 were unable to recover to normal April 1 levels, the report stated.
Monthly precipitation in January was 50-70 percent of average across most of Northern Nevada and the eastern Sierra basins. As of Feb. 1, water year to date precipitation since Oct. 1 is below average for Nevada ranging from 44 percent in eastern Nevada to 83 percent in the Owyhee River Basin. This is the driest start to a water year in eastern Nevada since SNOTEL sites were installed in 1981. The Lake Tahoe, Truckee, Carson and Walker basins have received between 63-80 percent of average, while the Humboldt basin has had 74 percent.
While the streamflows are expected to be low, the report stated reservoir storage is good and should stem summer drought concerns for water users and municipalities with rights to stored water. But with little additional water, streamflow will be reduced unless the weather changes.
The report calls for streamflow forecasts to be below average across the state with most in the 20-69 percent of average range. Humboldt River is expected to be just 12 percent of average streamflow from March through July.