From drought to deluge: Phillips Reservoir refills

By JAYSON JACOBY Baker City Herald July 08, 2009 12:00 am

Phillips Reservoir is lapping at the ponderosa pines again.

This is good for the pines.

But it’s better still for the potatoes and the alfalfa.

Boaters and anglers appreciate the situation, too.

The reservoir recently pulled off a feat that was common during the 1990s but has been rare since the turn of the century.

It filled.

Waves that typically splash onto steeply sloping banks of dirt, 10 or more feet below the high-water mark, come ashore today near the bases of the pines that line the long north and south shores of the roughly rectangular reservoir.

Phillips, which impedes the Powder River about 17 miles southwest of Baker City, reached its full-pool capacity, 73,500 acre-feet, on June 22.

(The Baker Valley Irrigation District, which manages the reservoir, can store as much as 90,050 acre-feet if necessary to prevent downstream flooding.)

This is just the second year the reservoir has filled since 2000.

The other was 2006.

Refilling was a routine event at Phillips during the 1990s; it happened every year from 1996-99.

A full reservoir means a couple of things — both of them positive — for Jeff Colton, the irrigation district’s manager.

First, it means the district can supply its dozens of downstream farmers and ranchers with their full allotment of irrigation water this summer: 3fi acre-feet per acre.

(One acre-foot of water would cover one acre of ground to a depth of one foot.)

Second, Phillips should hold enough water at the end of the irrigation season that even an average winter snowpack in the Elkhorn Mountains ought to be sufficient to refill the reservoir in the spring of 2010.

That post-irrigation carryover is crucial.

Conversely, two consecutive shallow snowpacks — or in some cases even one really skimpy one — can leave the reservoir less than half full before the irrigation season even starts.

Which basically describes much of the past decade.

In several years since 2000, Phillips held less than 15,000 acre-feet of water when irrigation ended in late summer.

Refilling the reservoir when it gets that low requires a bountiful snowpack. And we haven’t had many of those the past decade either.

You can monitor the reservoir’s level online at www.usbr.gov/pn-bin/rtgraph.pl/?sta=PHL&parm=AF.