Phoenix hasn't seen rain in 4 months. Too bad all that water rushed away this spring

I started saying months ago that it was going to get hot and dry this summer — and when it did, it would hit metro Phoenix with a vengeance.

That’s our reality.

One abnormally cool, wet winter is typically followed by an abnormally hot and dry summer. And fall. And maybe the winter after that.

Which means the precipitation on which we rely is increasingly becoming a matter of feast or famine:

Either there is so much that we can’t contain it, or there is nothing.

40% of SRP's runoff rushed downstream

Such is the case this year.

Arizona had one of the deepest, wettest snowpacks on record.

When it melted, a whopping 1.8 million acre-feet of runoff flowed down the Salt and Verde rivers and into the reservoirs that supply water to millions in metro Phoenix.

But about 40% of that runoff — or about 730,000 acre-feet, nearly enough to serve every Salt River Project customer for a year — overflowed our reservoirs and was sent rushing downstream.

Only about a quarter of that overflow is estimated to have sunk into the ground as it flowed, recharging aquifers along the way.

Meaning that most of the 730,000 acre-feet rushed out of town before it could be used or stored for later.

We could use that water for dry times

Now metro Phoenix’s heat is breaking records, and we’ve gone four months without rain.

And while SRP’s reservoirs remain close to full, a hot, dry summer will hurt us when that all-important winter runoff begins to flow next spring, because parched soil sucks it up like a sponge.

Imagine how much more water we’d have in reserve for times like those, if we simply had the infrastructure in place to handle it.

In fact, SRP has a fairly good idea.

3 projects could help us store most of it

A future Bartlett Dam expansion could provide space for an extra 350,000 acre-feet of water, or nearly half of what overflowed this spring, allowing it to stay in storage instead of flowing downstream.

SRP estimates this is enough water to serve about 1.1 million homes for a year.

A second project would create a two-way valve between SRP and the Central Arizona Project (for now, water can only flow downhill from CAP into SRP, not the other way around).

This Salt River Project-Central Arizona Project Interconnect Facility could move at least 50,000 acre-feet of excess runoff to underground storage facilities served by the CAP system, plus potentially more to CAP users.

That could lessen their need for Colorado River water in the short term and save more water underground, where a portion of it would not evaporate.

Slowing the flow can boost recharge

The third project requires no construction, simply federal permission to keep water for longer in existing flood-control space at Roosevelt Dam.

Extending how long water can stay in that space offers two big benefits:

• It would give cities more time to process the water that’s released (because water treatment plants can only intake so many gallons per day), lessening the need for other water sources, including CAP water and groundwater.

• It also would allow less water to be released at once, slowing its flow.

That slower flow would pick up less sediment and debris than a chugging torrent, which makes it less destructive and more useful to folks downstream.

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That water also would have more time to sink in — ensuring that a much larger percentage actually makes it into the aquifer.

SRP estimates that simply keeping water in that flood control space for up to 120 days would have saved 109,000 acre-feet from flowing out of the Valley this spring — enough to serve nearly 330,000 homes for a year.

This is the future of water management

These projects won’t completely stop overflows.

And it’ll be years before all three are online — perhaps 2032, at the earliest.

But they could vastly reduce the overflow and slow its release, providing even more benefits to the streambed and the aquifer than this year’s torrent provided.

That’s critical.

Because water systems across the West were built for steady-as-she goes precipitation, the kind that can provide a certain amount of runoff to replenish what is used each year.

We must become much more flexible to manage supplies in this feast-or-famine reality in which we now live.

And while it’s too late to cry over spilled … water … from this runoff season, at least we’re working to ensure the next wet winter is not a repeat.

Reach Allhands at joanna.allhands@arizonarepublic.com. On Twitter: @joannaallhands.

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This article originally appeared on Arizona Republic: Phoenix hasn't had rain in 4 months, despite a wet winter. What gives?