DWP has plan to cap­ture stormwa­ter that now en­ters the ocean

Los Angeles Times - - CALIFORNIA - By Monte Morin

It may not rain much in Los An­ge­les County, but when it does, a sin­gle storm can send up to 10 bil­lion gal­lons of wa­ter surg­ing into a vast net­work of storm chan­nels with a sin­gle des­ti­na­tion: the Pa­cific Ocean.

For decades, en­vi­ron­men­tal ac­tivists such as Andy Lip­kis have ar­gued that this rit­ual f lush­ing of stormwa­ter was a form of profli­gacy Los An­ge­les could ill af­ford. That wa­ter could be cap­tured be­fore it picked up ground con­tam­i­nants and used for ir­ri­ga­tion and other pur­poses.

Yet when the pres­i­dent and founder of TreePeo­ple be­gan propos­ing more than 20 years ago that the city “harvest” rain­wa­ter from the sky, the re­sponse was al­ways the same.

“They asked me what planet I was from. What was I smok­ing?” Lip­kis said with a laugh.

To­day, how­ever, at­ti­tudes are very dif­fer­ent. Af­ter four years of drought, un­prece­dented re­stric­tions on ur­ban wa­ter use and steady in­creases in the cost of im­ported wa­ter, of­fi­cials in Los An­ge­les and other cities are now look­ing at stormwa­ter runoff as more than just a f lood risk.

At a public hear­ing Thurs­day, the Los An­ge­les Depart­ment of Wa­ter and Power will present its Stormwa­ter Cap­ture Master Plan, an ini­tia­tive that of­fi­cials say will re­duce the city’s fu­ture re­liance on im­ported wa­ter and per­haps ad­dress a pre­dicted trend to­ward heav­ier, more in­tense rain­fall.

The plan in­cludes three largescale projects in the San Fer­nando Val­ley that would col­lect rain­fall in basins or washes and then slowly feed it into the city’s pri­mary un­der­ground wa­ter source — a process known as aquifer recharge.

The pro­posal also lists a va­ri­ety of smaller fea­tures that would be lo­cated on public, pri­vate and com­mer­cial prop­er­ties through­out the city: Wa­ter- per­me­able sur­faces that would help recharge the San

Fer­nando Val­ley ground­wa­ter basin, as well as re­designed “green streets” and pocket parks.

In­cen­tive pro­grams would be used to en­cour­age home­own­ers, schools or busi­nesses to in­stall large cis­terns, or cre­ate so- called rain gar­dens and swales that would help clean stormwa­ter runoff and di­rect it to land­scap­ing or cap­ture basins.

Cur­rently, the city col­lects an av­er­age of 27,000 acre- feet of rain­wa­ter each year. That wa­ter is cap­tured in f lood con­trol dams and spread­ing grounds, where it is al­lowed to f il­ter into the aquifer.

Un­der the Stormwa­ter Cap­ture Master Plan, the city could col­lect 100,000 to 200,000 ad­di­tional acre- feet of rain­wa­ter each year by 2035, depend­ing on how ag­gres­sively it pur­sued the plan, of­fi­cials say. One acre­foot of wa­ter is equal to 326,000 gal­lons, or about enough to sup­ply two house­holds with wa­ter for a year.

Ac­cord­ing to the DWP, the plan would cost $ 600 to $ 1,100 for each acre- foot of ad­di­tional stormwa­ter cap­tured — or $ 60 mil­lion to $ 220 mil­lion, depend­ing on what el­e­ments were im­ple­mented.

David Pet­ti­john, di­rec­tor of wa­ter re­sources at DWP, said the depart­ment does not en­vi­sion fund­ing the en­tire cost of the master plan pro­posal.

Projects within the plan would be ap­proved on a case- by- case ba­sis by the depart­ment’s board of di­rec­tors, and the DWP would seek fund­ing help from other agen­cies, such as the Los An­ge­les County of Depart­ment of Public Works, which would also have to ap­prove the projects.

“We rarely do these projects by our­selves with­out other par­ties help­ing us to fund them,” Pet­ti­john said.

At least one vo­cal critic of the DWP has ques­tioned how that ex­pense will be di­vided. Jack Humphre­ville, a mem­ber of the Greater Wil­shire Neigh­bor­hood Coun­cil, has writ­ten that he fears DWP ratepay­ers will be sad­dled with most of the cost.

The stormwa­ter plan has been in the works for two years and is part of a larger ini­tia­tive that in­cludes wa­ter con­ser­va­tion, re­cy­cled wa­ter and cleanup of the Val­ley aquifer.

Although the aquifer amounts to an enor­mous un­der­ground reser­voir, it con­tains zones of chem­i­cal con­tam­i­na­tion that limit its use.

“We need to get that ground­wa­ter basin cleaned up,” Pet­ti­john said. “That’s kind of a foun­da­tional ac­tion for our stormwa­ter cap­ture pro­gram.”

TreePeo­ple has been ad­vis­ing the DWP, and has funded sev­eral test projects in the lead- up to the plan­ning process.

Lip­kis said he be­lieves wide­spread de­vel­op­ment of de­cen­tral­ized projects will re­sult in more stormwa­ter cap­ture than DWP of­fi­cials an­tic­i­pate.

Large cis­terns that hold thou­sands of gal­lons of rain­wa­ter should be in­stalled in residential prop­er­ties through­out the city with gov­ern­ment help, he said.

He said that in Aus­tralia, more than a quar­ter of the res­i­dents in many cities in­stalled large cis­terns due to drought and ag­gres­sive in­vest­ment of in­cen­tives.

In an av­er­age year, Los An­ge­les re­ceives about 15 inches of rain.

Prior to ur­ban­iza­tion, much of this pre­cip­i­ta­tion would soak into the earth and make its way to un­der­ground aquifers.

Now, im­pen­e­tra­ble sur­faces such as streets, side­walks, rooftops and park­ing lots pre­vent this.

As a re­sult, runoff f lows into the ocean, car­ry­ing an­i­mal waste, trash, met­als, automotive oils and other con­tam­i­nants.

Re­searchers ar­gue that be­cause of cli­mate change, South­ern Cal­i­for­nia and other re­gions will even­tu­ally ex­pe­ri­ence fewer episodes of rain­fall, but that storms will oc­cur with greater in­ten­sity and gen­er­ate even more runoff.

“We do have fa­cil­i­ties in place that can catch quite a bit of stormwa­ter, but we want to in­crease that ca­pac­ity,” Pet­ti­john said. “Think of it this way. If all the rain fell on a sin­gle day, you’d have to build a fa­cil­ity big enough to cap­ture ev­ery sin­gle drop.”

The f inal hear­ing for the Stormwa­ter Cap­ture Master Plan is sched­uled for 6 p. m. at DWP Head­quar­ters, at 111 N. Hope St., Los An­ge­les.

‘ Think of it this way. If all the rain fell on a sin­gle day, you’d have to build a fa­cil­ity big enough to cap­ture ev­ery sin­gle drop.’

— David Pet­ti­john,

DWP’s di­rec­tor of wa­ter re­sources

Don Bartletti Los An­ge­les Times

WA­TER FLOWS into the Los An­ge­les River and from there to the ocean. Los An­ge­les col­lects an av­er­age of 27,000 acre- feet of rain­wa­ter each year, but un­der the DWP’s plan, could cap­ture 100,000 to 200,000 ad­di­tional acre- feet of rain­wa­ter each year by 2035.

Joel P. Lu­ga­vere Los An­ge­les Times

A TRUCK splashes through a f looded street in North Hol­ly­wood. The DWP hopes to build large- scale projects in the Val­ley that would col­lect rain­fall.

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