Environment & Science

LADWP sloshes in surplus water while other agencies still feel the drought

                               Water coming down the Los Angeles Aqueduct Cascades is slowed by the stair-like concrete baffle chutes.
Water coming down the Los Angeles Aqueduct Cascades is slowed by the stair-like concrete baffle chutes.
Sharon McNary/KPCC
                               Water coming down the Los Angeles Aqueduct Cascades is slowed by the stair-like concrete baffle chutes.
Following years of drought the Morris Dam protects Los Angeles County as part of Flood Control District in Los Angeles County, California on June 7, 2017.
Daryl Barker/KPCC
                               Water coming down the Los Angeles Aqueduct Cascades is slowed by the stair-like concrete baffle chutes.
The Morris Dam built in 1934 is still a central part of the flood control district in Los Angeles County, California on June 7, 2017.
Daryl Barker/KPCC
                               Water coming down the Los Angeles Aqueduct Cascades is slowed by the stair-like concrete baffle chutes.
The San Gabriel Dam provides flood protection and hydroelecric power to the San Gabriel Valley in Los Angeles County, California on June 7, 2017.
Daryl Barker/KPCC
                               Water coming down the Los Angeles Aqueduct Cascades is slowed by the stair-like concrete baffle chutes.
The Morris Dam with its attached spillway in Los Angeles County, California on June 7, 2017. Following a season of heavy rain the reservoir is reaching the dams capacity to retain water.
Daryl Barker/KPCC
                               Water coming down the Los Angeles Aqueduct Cascades is slowed by the stair-like concrete baffle chutes.
The Los Angeles Aqueduct Cascades in Sylmar, June 28, 2017
Sharon McNary/KPCC
                               Water coming down the Los Angeles Aqueduct Cascades is slowed by the stair-like concrete baffle chutes.
Northern California snowmelt water cascades down the Los Angeles Aqueduct in Sylmar at the end of its 233-mile journey.
Sharon McNary/KPCC
                               Water coming down the Los Angeles Aqueduct Cascades is slowed by the stair-like concrete baffle chutes.
Anselmo Collins of the Los Angeles Department of Water and Power oversees the historic Los Angeles Aqueduct. Behind him, snowmelt from Northern California arrives in Los Angeles on the stairstep-like Cascades alongside Interstate 5 in Sylmar.
Sharon McNary/KPCC
                               Water coming down the Los Angeles Aqueduct Cascades is slowed by the stair-like concrete baffle chutes.
Water from Northern California arrives in Los Angeles on a big pipe that is part of the Los Angeles Aqueduct. From this location in Sylmar, it goes to a water treatment plant a mile to the south, then on to L.A. homes and businesses.
Sharon McNary/KPCC
                               Water coming down the Los Angeles Aqueduct Cascades is slowed by the stair-like concrete baffle chutes.
Breana Nunez enjoys a dip in a natural pool formed at the West Fork of the San Gabriel River.
Sharon McNary/KPCC
                               Water coming down the Los Angeles Aqueduct Cascades is slowed by the stair-like concrete baffle chutes.
Markers indicate the current water level at the Morris Dam in Los Angeles County, California on June 7, 2017.
Daryl Barker/KPCC
                               Water coming down the Los Angeles Aqueduct Cascades is slowed by the stair-like concrete baffle chutes.
The Morris Dam Operator, James McGowan, tests water levels at the facility in Los Angeles County, California on June 7, 2017.
Daryl Barker/KPCC
                               Water coming down the Los Angeles Aqueduct Cascades is slowed by the stair-like concrete baffle chutes.
The Morris Dam spillway in Los Angeles County, California on June 7, 2017. The spillway, shown here, is a feature of the dam that is utilized to control excessive water levels in the reservoir.
Daryl Barker/KPCC
                               Water coming down the Los Angeles Aqueduct Cascades is slowed by the stair-like concrete baffle chutes.
Jose Aguilar who works at the Morris Dam, inspects the site with Kerjon Lee from the Los Angeles Public Works Department in Los Angeles County, California on June 7, 2017.
Daryl Barker/KPCC
                               Water coming down the Los Angeles Aqueduct Cascades is slowed by the stair-like concrete baffle chutes.
The San Gabriel Dam reservoir serves as a source of firefighting water in Los Angeles County, California on June 7, 2017. During the Angeles National Forest fire in 2016 this site acted as a primary source of firefighting water for the Los Angeles County Fire Department.
Daryl Barker/KPCC


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On the heels of record rain and snow in California, some local water agencies are experiencing a bonanza of surplus supplies. But others that rely on groundwater are still feeling lingering effects of the state's five-year drought. 

Perhaps the most visible sign of this summer's water feast can be seen from the I-5 freeway north of Balboa Boulevard, where the historic Los Angeles Aqueduct crosses into the San Fernando Valley.

It's at that point where water in the aqueduct tumbles down an open-air staircase of concrete blocks called the Cascades. It's meant to slow the pace of the water as it rushes downhill, but the speed of the flow is still about 700 cubic feet per second. A cubic foot is about the size of a basketball.

This year the Cascades are running full.

“All of a sudden now we have so much water that we got to figure out what to do," said Anselmo Collins, managing water utility engineer for the Los Angeles Department of Water and Power.

All that water is coming from this winter’s record snowpack up in the Eastern Sierra, which saw more than twice the normal amount of precipitation. As it melts, the water flows 233 miles south to this hillside point where, in 1913, water engineer William Mulholland famously told Angelenos to come take the water.
 
This year, after five years of drought, there is finally a lot to take, and Collins is DWP’s point person to figure out what to do with all the water.
 
The snowmelt will produce a million acre feet of icy water, but the L.A. aqueduct can carry only half that running full from April through next March.
 
“The challenge is, there’s more water than we can actually consume,” Collins said.
 
The city had to get creative to cope with all the water. First off, the surplus has allowed L.A. to scale back its purchases of imported water from the Metropolitan Water District.
 
Because of that, city water customers will see a small reduction in their bills. Typically there is a surcharge for water bought from MWD. The city now has a deal to transfer some of its water to MWD in exchange for lower water prices later.

The surplus also allowed the city to refill the empty Silver Lake Reservoir with drinking water instead of treated wastewater.

Even before the aqueduct began delivering snowmelt, DWP knew it would have a surplus. So the it refilled the reservoir with drinking water -- something that would have been unthinkable during the drought.

The original plan to use recycled wastewater also would have required a new pipe to connect the artificial lake to a treatment plant. 

Surplus aqueduct water will also be used to recharge underground aquifers that had become depleted. Workers are renovating two miles of a nearly 100-year-old pipeline known as the Maclay Highline to deliver aqueduct water to some flood control channels that lead to a water spreading ground in Pacoima.
 
“We thought it was a great idea to take the excess water that we have from our own aqueduct and use it to recharge our own groundwater basin,” Collins said.

"Excess water" though is not a luxury all water agencies have.

Rain and snow in the San Gabriel Mountains was above average last winter, but that did not translate into a surplus of water for the 30 to 40 percent of county water users who rely on groundwater supplies.

“We still consider ourselves in somewhat of a drought condition,” said
Mark Pestrella, who oversees the system of dams, reservoirs and water spreading grounds run by the L.A. County Department of Public Works.

That's because years of drought sucked so much soil moisture from the mountains that they acted like a giant sponge during the rains. The parched soil absorbed a lot of the water that otherwise would have drained into the county's flood control system.

“We need two or three more years of the same rain,” Pestrella said.

 He might get his wish. Right now, forecasters say California has a better than 60 percent chance of average to above average rain this winter.