States back plans for Colorado River

Yuma Sun - - NEWS -

DEN­VER — The Colorado River is ail­ing, af­flicted by a pro­longed drought and in­creas­ing de­mand from seven South­west­ern U.S. states that de­pend on the wa­ter­way.

Those states ten­ta­tively agreed this week on a new plan to put the river on life sup­port.

The Colorado sup­ports about 40 mil­lion peo­ple and 6,300 square miles (16,300 square kilo­me­ters) of farm­land in the U.S. and Mex­ico.

But the out­look is grim. Some sci­en­tists say this isn’t a drought that will come to an end some­day, but a long-term shift to a drier cli­mate.

On Tues­day and Wed­nes­day, the states that de­pend on the river and the U.S. govern­ment rolled out new drought con­tin­gency plans de­signed to keep the river alive. Six things to know about the plans:

THE ROOT OF THE PROB­LEM

When the United States and Mex­ico divvied up the Colorado River and its trib­u­taries, they over­es­ti­mated how much they had.

The first agree­ment was drawn up in 1922, when the ne­go­tia­tors be­lieved they had about 16.5 mil­lion acre-feet a year to work with, based on the river’s known his­tory. An acre­foot, or 1,200 cu­bic me­ters, is enough to sup­ply a typ­i­cal U.S. fam­ily for a year.

But their as­sump­tions were based on an ab­nor­mally wet pe­riod. By 2018, the 100-year av­er­age flow de­clined to about 15 mil­lion acre-feet, ac­cord­ing to the U.S. Bureau of Recla­ma­tion, which man­ages hun­dreds of dams.

Cli­mate change, droughts and de­mand from grow­ing cities has in­creased the gap be­tween how much wa­ter the river sys­tem car­ries and how much peo­ple want — what river man­agers call a “struc­tural deficit.”

THE NEW PLAN

The idea is sim­ple: Use less and save more in the sys­tem’s two gi­gan­tic reser­voirs, Lake Mead and Lake Pow­ell. Stored wa­ter pro­vides a pre­dictable sup­ply even in the dri­est of dry years.

The reser­voirs also have to be kept high enough to turn gen­er­a­tors that pro­duce elec­tric­ity for thou­sands of homes and busi­nesses. In­come from the sale of that power pays for pro­grams that save en­dan­gered species and main­tain the dams.

The plan has two ma­jor com­po­nents. One is for Colorado, New Mex­ico, Utah and Wy­oming, known col­lec­tively as the Up­per Basin, where moun­tains col­lect snow that pro­vides most of the river’s wa­ter. The other is for Ari­zona, Cal­i­for­nia and Nevada, known as the Lower Basin, where the river even­tu­ally winds up.

WHAT THE UP­PER BASIN WILL DO

The Up­per Basin states agreed to try and keep the sur­face of Lake Pow­ell at or above a tar­get level of 3,525 feet (1,074 me­ters) above sea level. That keeps the reser­voir 35 feet (11 me­ters) higher than the min­i­mum re­quired to run the hy­dro­elec­tric plant.

The plan gives the states flex­i­bil­ity to man­age three big up­stream reser­voirs in a co­or­di­nated way to keep Pow­ell above the tar­get. If Pow­ell is pro­jected to drop below the tar­get, the states would come up with a plan to try to pre­vent that.

If the Up­per Basin states have more wa­ter than they need, the plan al­lows them to store some of it in reser­voirs for later use, with­out fear that it will be drained into the Lower Basin and used there.

WHAT THE LOWER BASIN WILL DO

Lower Basin states agreed to use less wa­ter than they’re legally en­ti­tled to as a way to buoy the level of Lake Mead, which is down­stream from Lake Pow­ell. The lower Lake Mead falls, the more they would cut back.

If Lake Mead falls below a set level, Ari­zona would cut back by up to 9 per­cent, Cal­i­for­nia by up to 8 per­cent and Nevada by a fixed 3 per­cent.

Cal­i­for­nia agreed to con­serve much sooner than it is legally ob­li­gated to.

“That’s what makes this so sig­nif­i­cant,” said Pat Mul­roy, an ex­pert on the Colorado River and for­mer head of the South­ern Nevada Wa­ter Au­thor­ity, serv­ing Las Ve­gas and other cities. “They are the ones that needed to come to the table, and they came.”

‘THE LAW OF THE RIVER’

The drought con­tin­gency plans ex­pand what is called “the law of the river,” a col­lec­tion of in­ter­state agree­ments, in­ter­na­tional treaties and court rul­ings that gov­ern the river.

The law of the river gave 7.5 mil­lion acre-feet (9.3 bil­lion cu­bic me­ters) a year to the Lower Basin states, slightly less than that to the Up­per Basin states and 1.5 mil­lion acre-feet (1.9 bil­lion cu­bic me­ters) to Mex­ico.

The new con­ser­va­tion agree­ments are on top of pre­vi­ous cut­backs agreed to in 2007. Those cut­backs proved to be too lit­tle, how­ever, lead­ing to this week’s agree­ments.

WHAT’S NEXT

The drought con­tin­gency plans still must be ap­proved by the seven states and, in some cases, mul­ti­ple agen­cies within states. The U.S. De­part­ment of In­te­rior and Congress also have a say. Mex­ico agreed last year to par­tic­i­pate if the U.S. states came up with a plan.

Most river ex­perts say the new agree­ments amount to first aid, not a cure. In the long run, the states will have to find a way to leave more wa­ter in the river or put some back to re­duce the gap be­tween sup­ply and de­mand.

AS­SO­CI­ATED PRESS

IN THIS MAY 2018 FILE PHOTO, the low level of the wa­ter line is shown on the banks of the Colorado River in Hoover Dam, Ariz.

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