Water Education Foundation
This is just one post in the Drought, Weather & Snowpack Category
Click here to view all posts

A look at the drought monitor and reservoir levels

Posted by: Maven on March 13, 2009 at 7:55 am

Here’s a look at the latest drought monitor, which shows improvement over last week’s. Is the drought over? The Accu-Weather Western Weather blog weighs in:

While the extreme drought area in northern California is gone, and the severe drought area in northern and central California has shrunk a little, widespread moderate to severe drought conditions continue through south-central portions of the state.

The weather pattern for the next week will not help this one bit, especially in Central California. There will be some rain and mountain snow in the northern third of the state Saturday night and Sunday but this will not be a heavy event for most. From about the central and south Bay Area to Stockton and south no rain is expected for at least the next 7 days, perhaps longer. Northern most California will be dry from Monday through Wednesday.

A Capital Press editorial puts the numbers into perspective:

For the record, across the state last week, storage reservoirs were at 66 percent of capacity with less than 45 days before shifting weather patterns will all but remove chances of precipitation until November.

The Sierra Nevada snowpack, after a dismal winter, has climbed to about 80 percent of average on the strength of a couple of good February storms.

That snowpack number needs to be put into perspective. One year ago in early March, it was 114 percent. Then a record dry spring came along. The snow vanished, much of it straight into dry soil rather than running downstream. Reservoirs were then drawn down to augment streamflow and partially meet 2008 obligations of irrigation districts.

And indeed, the snowpack doesn’t look that bad. However, normal snowpack does not mean normal runoff, and it’s the runoff that counts. As the snowpack melts, if the ground is parched and dry, much of the melt will rewater the watershed. If it is a dry spring, the snowpack can directly sublimate into the atmosphere.

The state’s largest reservoirs (Shasta, San Luis, and Oroville) remain about half full. Here’s a look at reservoir levels statewide:

(Sorry for the small size – I’m in Sacramento at the Water Education Foundation’s Executive Briefing and am running from a laptop this week. Click on the picture to see it directly from the DWR website.)

For a lot more information on California’s drought and hydrologic conditions, check out this 16-page summary of water conditions from the Department of Water Resources by clicking here.

March 13, 2009 · Filed Under Drought, Weather & Snowpack

Comments

Leave a Reply