2kakkatin. 23(1977)471-483 OZkevier S5sntificPubIishingCompany. Amsterdam-Frintedin~eNetherianrIa

471

PLAXNIKG 'IOHSST FDTURS WATER REQiiEE'~~ BY OI&7.XGE COLIST. CALJIFOi?XIA

Preston Allen, Hillian Khittenberg and David Argo Orange County Water District Fountain Valley, California

The Orange County Hater District (OCXD) is challenged with nanagenent

of the rxajor groundwater basin in Orange County, California. Its

responsibilities include replenishPent and protection of both quantity

and Tuality of the groundwater. Tine District has historically considered

all possible alternatives for maintaining the groundwater basin. It has

spread local runoff, utilized all available inported water, and produced

reclaimed wastewater to replenish the basin and retard seawater intrusion.

The construction and impltzxentation 0E Water C.zcto_y 21 has deronstratcd

the feasibility and proven the techne‘.. of wastewater reuse projects

to ncet the increased d-ds of the twenty- Lrst century.

In the future, Orange County and other regions of the world will

n.\ longer have the luxury of depending totally upon traditional water

supplies or rnportation of water frozn the distant vatersheds. As a

result, Southern California will not have the water affluence to dispose

nore than half of its water supply to the ocean. Conservation zr.d reuse

will be the guidelines for extending water resources. Because of these

factors, and since Water Factory 21 has opened the door by demonstrating

the feasibility of recleation, OCWD will endeavor to rerzzin in the

forefront by developing innovative projects to produce reusable water.

In the future, options such as the Orange County Irrigation and Reuse

System, the Seal Beach Reclamation Plant, the Anahein Forebay Project

and tke corona Desalter will provide vater supply alternatives. It is

our belief that reclamation, desalting and reuse will have significant

roles in future groundwater cznagaent and water supply,.not only in

Grange County but also throughout the world.

472

orange county is located in southern calffonlia's coastal plain

between the cz,or cities of Los Angeles and San Diego (refer to Figure 1).

of the county's total area of 2036 sq km , approxinately CO percent is

cmprrsed of Dountains and hills; the rexmining 60 percent, gently

sloping lahds entering the Pacific Ocean to the southwest. The Santa

~na hiver, which is the largest in Southern California, provides an

average of 75 million cu m ennually. The clisxate of Orange County carp

be classified as Kediterranean, vith -, dry s1p9ers end nald winters.

The average rainfell is a_pproxims tely 33 QS per year. Esticates of

total local yield of water supplies, including precipitation, return

flows, andbaseand stomflovs through the Santa Ana River, range from

146 to 160 pillion cu n per year , 2 sparse 25 percent of Grange County's

water needs.

Orange cou.ky*s grovtb rate follows e recachzbly close resecblance

to the population 9mwth of the vorid. As shown in Figure 2, frca the

early 1800's to 1940 grcvth was relatively slow, increasing frca appoxi-

nately 20,000 to 130,000 people. Froze 1940 to 1950, population doubled

to 220,000. During the next decade this rapid grovth increased and

population tripled, reaching 705.000. During the 1960's the county's

population doubled Lo 1.420,OOO. Tbegrovthratehasbegun to slovrn

the last six yeers, reaching 1.720.000 in ,7uly, 1976. It is anticipated,

however, that in the next 50 years the population of Orange County will

continue to grov. and by the year: 2026 will have doubled to about 3,350,OOO.

This increase in population has resulted in the transformation of a

predollinmtly agricultural area to an urban cozzxunity with significautly

differeat attitudes and dmands upon the water supplies. FISShOUIlFn

Figure 3. ohly agricultural water decacds have been vithin the Units of

local yield of the basin. Since l Ae 1900's the water demands in Orange

County have been in excess of the natural anount of uater avaFlable to

recharge the besin. In 1926, vhen only 60.000 people lived in Orange

=mty, totaldaccsticuaterusewa~ approxiczately 154millioncumpe.c

year. Today's population of 1,720,WO uses nearly 493 million cu P

annually for dunestic purposes.

PACIFIC

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prom the sfxadpoint of water supply, the vast graunduater basfn

underlying the major portion of Orange County has been a primary factor ihtheaxmty*s populationgmuth. Asurbandemandsiuc~eased,itn~

the graunduater basin which provided additional supplies. Continued

useofthegr0undwater reservoir ioquaritities exceeding uatwal recharge

led to A serious overdraftcoadition. By the year 1956, over 80 percent

of thegroundvaterbasiuvasoverdrafted,bringiug groundwater elevations

belowse~levelaudcausing seawater iutrusionalortg the ax.stliue.

Allof SoutheruCaliforniahas experienced similar growth; local ~udg-rouud~tersupplies havebeen iusufficieuttomeetthe eqzmdiug

needs. Thus SoutileinCalifOruiAAndDrangecouuty. fACedVitb increased

vaterdeztaudacddiniuishiag supply,begau exaniningdistantAlten?ative

watex su9plies. In 1928 the cities of Santa Ana, Anaheim, Fullerton aud

ten other cities and agencies in Los Zingeles, Orange and San Diego

Counties organized an association to form the Metropolitan Kater District

of Southern California @HD). The prime purpose of MHD uas to develop

and build the Colorado River Aqueduct, which is now ca_Sable of deliveriug

up to four billion liters per dry over a distance of 390 lm from the

Colorado River. IA 1951. with water supply demands continuing to 9?xm,

the California Legislature iuitiated the California State Hater Project.

It5 Durpose is to re9ulatGcn4mff fram the massive Saaaflento River

watershed. thus allovikg cont+uxxzs trausport of uater fraa Korthern

California to Southern Califo&a.

As shown in Table 1, the volume of i.cqorted uater increased from

almost 1.9 million cu m in 1940 to over 247 million cu P in 1975. At

the sane the groundrater pxduction aZso increased und in 1975 reached

its third highest level iu history, with ovet 278 million cu m extracted.

Where is the vater cuaiag frtxm to meet the increased demands? The

major portion of the uater no31 being used in Orange County is imported

franoutside thebasiu,withthebalance derived ftom grouudwter and

local surface supplies. IA 1975 total water use uas 439 uiX.ion N m And

consisted of 153 mil1ion.Cl.l m C.f *rt y=cz, 278Patllfoncum ofgrou&-

water and 8 million N m of bz& surface supply.

TABLE I

WATER SUPPLIES IN THE OR&NGE COUNTY WATER DISTRICT*

SEASON IMPORTED WATER ENDING STATE WATER SEPT 30 COLO,RADO RIVER PROJECT

1940 1.796 0

1950 47.437 0

1960 281.335 0

1970 239.453 0

1971 234.545 0

1972 228.970 0

1973 210.752 0.617

1974 189.S70 80.266

J-975 209.056 38.029

*All units are million Cubic meters.

TOTAL GRODNDWATER

1.796 206.981

47.437 252.621

281.335 255.887

239.453 239.766

234.545 251.539

228.970 282.531

211.369 265.182

269.856 269.968

247.053 278.274

418

Inported Water

Construction of the Colorado Rrver Aqueduct began soon after the

forcation of xii in 1926, and in 1941 the initial develo_ment of the

aqueduct was completed. It becarce obvious in the early 1950's that

southern California vould requtre additional water supplies. Tiiuc a

nzjor expansion was cccpleted in 1961, increasing the aqueduct capacity

to 3,785,OOO cu n per day.

The Colorado River Aqueduct enables KWD to cake water deliveries of

core than 1,234 million cu P per year across 390 km of desert and countam

ranges, from the intake pumps on the Colorado River to its teminal

reservoir in Southern California. In the course of the aqueduct, water

is lifted 493 I;I by five separate puoping plants, each of whicn has a

series of nine pucps capable of pmping 340 cu n per minute. Tine kilowatt

rating of the pump adzors vvies according to lift, the largest being

9,321 kw and raising the water over 134 m. A total energy requirement

of 1.69 kwh/cu nil is needed to deliver the water to Orange County.

The Califorria State Water Project began with construction in 1951

of several dams on the tributaries to the Sacrecento River. Once the

dams were completed and runoff controlled, water could be diverted and

tram-ported to the Central Valley and Southern California. Transporting

water froa north to south requirmd construction of the largest aqueduct

in the world, the California Aqueduct. Through a systers of dams,

canals ar.9 puzps. the systen can move 2.447 million cu m of water annually

approximately 725 kn. Eight _pucping plants lift the water frco. near sea

level in the San Joaquin Delta and deliver it southward to the highest

point, about 1,067 P above sea level at Silverucod Lake. Tine A. D.

Edconston pumping station, largest in the system, has 14 units of

59,656 kw elevating watff 587 n in a single litt. A total net energy

requirecent of 2.69 kuh/cu P is used to deliver state water to Southern

California.

Through these import systems large volrnes of water have been

transported to Orange County. During 1975 over 75 percent of the non-

local water supply (imported water and runoff) to the area of OckD for

direct use in groundwater replenfshxuent was purchased through the State

Water project and the Colorado p.iver weduct (see Figure 4).

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Groundwater

In 1933 the Orange County Water District (OCWD) was organized by an

act of the California Legislature for the purposes of: (1) managing the

groundwaterbasin; (2) conservinggroundvater quality and quantity; and

(3) protecting Orange County's water rights and the natural flow of the

se.ntaanaRiver. Currently the District coaprisee 81,810 ha overlying

the coastalbasinof thesanta- River- The District serves about 40

percent of the county land area and 1.5 aillion people, abzost 90 percent

of the county's total population.

Groundwater is usually considered a local source of supply: however,

this is not totally the case in Orange County, since high decands cannot

be replenished from natural resources. Extensive use of the groundwater

basin between the years 1926 and 1956 crea'k!d an overdraft condition.

resulting in lowered vater levels and seawater intrusion. Realizing the

severity of depletion in the groundvater basin, OCWD began recharging

the basin with inported water frcnz the Colorado River when it was first

available in 1949. Since OCUD began its program to ezpand groundwater

storage it has utilized over 2.8 billion cu m of ir_mrted water. Use of

inported water frcnn the Colorado River and the State Water Project for

groundwater replenishnent has elevated the water table and successfully

halted seawater destruction of the basin.

Even with inportation of additional nonlccal supplies. the District's

nanagenent prograns necessitated development of additional supplies to

neet ezpanding needs and to protect against the threat of seawater

intrusion. To fulfill these purposes the District has constructed Hater

Factory 21, a wastewater reuse facility vith the mst advanced design in

the world. Water Factory 21 consists of four elements which, combined,

enable the District to inject over 34 nillion cu III of high quality water

annually. The a&or conponent of the Water Factory is the advanced

wastevater treatnent plant. Tnis facility takes secondary treated

vastewater, treats it with line and rezmves -da, ztnd then filters

the water twice - first through conventional nultinedia filters; second

through activated carbon - to recovedissolvedorganics.

Part of the water that has received the activated carbon treatment

is diverted to the world's larges' c reverse osmsis (PC0 desalting plant. This syste3 vi11 produce 19,000 cu P per day of very hfgh quality mter

with a very low salt content. The other two elements of the Water Factory

481

are a group of four deep wells and 23 injection wells. The deep wells

are 305 to 366 CI deep, penetrating aquifers tha tare unaffectedby the

seawater intrusion. Each uell is capable of producing up to 221 l/see

of low tatal dissolved solids (TDS) water for blending with RY and

advanced waste treatseot (Am?1 water for iojection into the barrier

systels. The 2: injection wells have a total of 81 injection poiots and

allow the blended water to form a hydraulic aumod in four separate

aquifers to retard the influx of seawater,

F73TuRE CICUD UATER SUPPLY PIMGFm45

In keeping with the imaginative aud pioneering philosophy of the

development of Water Factory 21. the District plans to embark on several

other alternative vater supply projects. Future projects include: an

enviromental irrigation system. which will use rechimed water for

greenbelt and park landscape irrigation: tvoplants siatilar toWater

Factory 21, which uould recycle wastewater for grounduater recharge and

injection: and projects which could include desalting of either brackish

waters or seavater.

Orange County Irrigation and Reuse System

Wst isizinsnt of all proposed projects is the wnstruction of the

Orange County Irrigation and Reuse Syste=l, a 57.030 cu P per day system

thatuould allow for eovironueotal irrigation vith treated wastewater.

This project would provide for irrigation of golf courses, caeteries,

packs and greenbelts,aod for limited use in the concrete industry for

boiler cooliog,washdown and dust control. Advancedvaetewater treatsent

of secondary effluent for this project would regutie only direct filtra-

tion, disinfection and pumping into a distribution system. This treatment,

alLtnoughlimited,wouldncetallhealth safequads requiredbythe

Califoroia Kealth DepartmentoFthoutraumviag nutrients thatwould

provide significant fertilizer value to the ~~4. Using reclaimed

water for irrigation of parks and greeobelts,uillraduce the demand cn

groundwater ait ioPorteddomenticwater, therebyconserviogbothpotable

brafez supPlies.

Seal Beach Reclamation Plant

The vicinity of Water Factory 21 is not the only location where

seawater intru+on presents a probiem. Approximately 25 miles north of

the Water Factory, in the Alamitos Gap, GCWD and the far3 Angeles County

Flood Control Dtatrict hiiVe built the Alar&toe Barrier Project to protect

the groundwater basins of central Los Angeles County and northweet

OrangeCounty. This project, in operation since 1965, incorporates a

series of extraction and injection wells about two miles inland from the

mouth of the San Gabriel River. Injection water is supplied from both

the Colorado River end the State Water Project.

The OCWD recently initiated studies to determine the feasibility of

providing a plant similar to Water Factory 21 to produce water for

injection into,the Alamitos Barrier system. This project, the Seal

Beach Reclamation Plant, scald consist of primary, secondary and tertiary

treatment processes to produce 7.8 million cu m per year of high quality

wastewater for injection. Whereas the present barrier project depends

on imported waters , which are subject to curtailment during drought

periods and disaster, a reclamation project would provide a firm supply

not subject to such cutbacks.

Anaheim Forebay Reclamation Plant

Groundwater provides more than 60 percent of the water used within

the OCWD, and recharge of the groundwater basin with imported water is

essential to maintain the quantity of available water. The quality of

the groundwater is also significant. It has been deteriorating for many

years, through rep1enishmer.t *‘ith high 'SDS (750 mq/l) Colorado River

water. Use of imported Colorado River water has resulted in an adverse

salt balance, with an average accumulation of 100,000 tons per year. In

order to reverse the trend of increasing salt accumulation, improve

quality and provide an alternative supply for imported water, the

Anaheim Porebay project has been conceived. This project would include

diverting 47,000 cu m per day of raw municipal sewage to a conventional

primary and activated sludge treatment plant. Secondary treated effluent

would then receive advanced treatment by processes similar to those at

Water Factory 21, including desalting. Brines and sludges would be

disposea Into a Saline waste line to the ocean, currently under

construction. The high quality product water (less than 500 mg/l TDS)

would then be available for recharge to adjacent spreading ponds or for

other beneficial uses.

Corona Desalter

The salt balance in the Orange County basin is also affected by

the discharge of upstream wastes into the Santa Ana River. To alleviate

the massive discharge of salts into the river and subsequently into the

Orange County basin, a large system is currently under construction to

intercept and transport the highly salt-laden wastes to the ocean from

upstream dischargers. Other wastes, such as treated municipal sewage,

will require additional treatment before discharge to the river in order

to meet the mandated regional goals. One project that has been examined

is the Corona Desalter.

The city of Corona, located just northeast of the Orange County

line, discharges its wastes into the Santa Ana River. Planners are

examining several alternatives for meeting discharge requirements for

that area. One of these alternatives is to treat the city wastes with

conventional primary and secondary treatment, percolating part of the

secondary effluent into the local groundwater basin. The remaining

effluent vould receive tertiary treatment, demineralization and discharge

to the Santa Ana River. This process would minimize cost for tertiary

treatment and demineralization ahd would also reduce the problem of

risi:lg water that would result from percolating all of the secondary

effluent. oranqe Cour.ty would benefx 't from this project by receiving

water with low salt ccntent, thax Aproving the quality of the river and

ultimately improvlr,q the salt balance ir. the Orange County basin.