Santa Margarita Groundwater AgencyOctober 25, 2018

City of Santa Cruz Water System and Supply Augmentation Strategy

2

3

Santa Cruz’s San Lorenzo River Water Rights

4

Santa Cruz’s Sources of Supply

5

Beltz Wells

4%

Tait Wells

3%Loch

Lomond

22%

San Lorenzo

River

46%

North Coast

Streams

25%North Coast Streams

(1890)

Loch Lomond Reservoir

(1960)

San Lorenzo River

(1924)Beltz Wells

(1964)

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7

The 20 year water demand forecast, including projected growth and consistency

with the City’s General Plan, is FLAT

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Service Area Population and Population Forecast*

20101 2020 2025 2030 2035

Inside City2 59,946 66,860 70,058 73,375 76,692

Outside City3 31,342 32,543 33,562 34,614 35,698

Service Area Total

91,288 99,403 103,620 107,989 112,390

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* – As used in City of Santa Cruz 2015 Urban Water Management Plan 1 – Actual population per 2010 Census2 – AMBAG 2014 Regional Growth Forecast (adopted June 11, 2014), includes UCSC population3 – Developed by Water Department Staff from 2014 Regional Growth Forecast data

Santa Cruz’s Supply

is Highly Variable

10

0

50

100

150

200

250

300

350

400

Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct

Loch Lomond

Tait Street

North Coast

Beltz Wells

TOTAL DEMAND

Mill

ion

of

Gal

lon

s

The projected worst year gap is BIG – peak season shortage with DFW-5 flows is 1.2 bg

billion gallons

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Fish Flow Commitments

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Putting the City’s Summer Fish Flow Commitments in Context

June Fish Flow Releases

0

2

4

6

8

10

12

Year Type

Mill

ion

s o

f G

allo

ns

pe

r D

ay

Driest Dry Normal Wet Wettest

June Water System Production

0

2

4

6

8

10

12

June Production

Mill

ion

s o

f G

allo

ns

Pe

r D

ay

2012 (Normal) 2013 (Dry) 2014 (Dryest)

2015 (Dry) 2016 (Normal) 2017 (Wettest)

2018 (Dry) 13

Water Supply Advisory CommitteeApril 2014 – October 2015

• 14 citizens appointed by the City Council

• Interests represented included: inside and outside city water customers, the Chamber, Coastal Watershed Council, Desal Alts, Sierra Club, Surfrider, Sustainable Water Coalition, the Water Commission and 3 community-at-large members.

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WSAC’s Problem StatementJuly 2015

• Limited Storage

• Need to meet fish flow requirements and prepare for potential climate change impacts

• Resulting peak-season gap: ≈1.2 billion gallons worst year shortage

• Water conservation alone is not enough

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Our Water, Our Future: the October 2014 “Santa Cruz Water Supply Convention,” showcased more than 40

water supply solutions and attracted 350 people

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Nearly 100 Alternative Water Supply Solutions Identified and Screened

• Expanded conservation, e.g.,

– Peak season demand reduction

– Water neutral development

• Decentralized systems, e.g.,

– Graywater

– Rainwater catchments

– Water from humidity in the air

• Winter flow harvest, e.g.,

– Passive and active recharge

– Water transfers and exchanges

• Water reuse

– Various approaches to non-potable and potable reuse

• Desalination

– Various locations and technological approaches to seawater desalination

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WSAC Supply Augmentation Recommendations

1. Implement additional water conservation efforts

2. Explore the feasibility of winter water harvest to create drought supply of 3 billion gallons to provide for 2 years of back to back drought

A. In-lieu water transfers/exchange with Soquel Creek Scotts Valley and/or San Lorenzo Valley water districts

B. Aquifer storage and recovery (ASR) in the Santa Margarita and/or Santa Cruz Mid-County Basins

3. Explore the feasibility of alternative water supplies to supplement existing sources during droughts

A. Recycled water

B. Desalination

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19

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Strategy 1Element 1 –

In Lieu

Strategy 1 Element 2 –

ASR

Strategy 1Combined In Lieu and ASR

Strategy 2Element 3 –

Purified Recycled

Water

Strategy 2 Element 3 –Desalination

Thre

sho

ld M

etri

cs

(qu

anti

tati

ve

ind

icat

ors

)

TechnicalFeasibility

Y/N Y/N Y/N Y/N Y/N

Cost (ACAYY) Annual $/mg of yield

Annual $/mg of yield

Annual $/mg of yield

Annual $/mg of yield

Annual $/mg of yield

Yield Billion gallons Billion gallons Billion gallons Billion gallons Billion gallons

Timeliness Meets/Does Not Meet

Meets/Does Not Meet

Meets/Does Not Meet

Meets/Does Not Meet

Meets/Does Not Meet

Gu

idin

gP

rin

cip

les

(qu

alit

ativ

e, c

on

sum

er

rep

ort

typ

e in

dic

ato

rs) Public Health

Public Acceptance

Regional Collaboration

Plan Goal

Incremental Implementation

Ad

dit

ion

al

Val

ue

s SystemRobustness

System Resilience

System Redundancy

Adaptive Flexibility

QUESTIONS?