2019-2020 water resources planning

October 24, 2019 Water Resources Planning

2019-2020 Water Resources Planning

Workshop #2October 24, 2019

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Agenda for the WorkshopIntroduction & PurposeDry Year Groundwater Operations

HistorySustainable Groundwater Management ActPlanning-Level Modeling of Future ScenariosBalancing Objectives

Recycled Water Planning & DirectionConclusions & Next Steps

2October 24, 2019 Water Resources Planning


Introduction & Purpose

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Purpose of Water Resources Planning Workshop Series 2019-2020

Discuss key planning objectives, criteria & elements of the District’s 1995 Integrated Resources Plan in light of changing timesObtain Board’s permission to “step outside the lines” of 1995 policy criteria for planning-level assessmentsEvaluate widest array of options for long-term water supplies & initiatives


Meeting #1 – July 25, 2019

Reviewed significant upcoming changes affecting water supplies & demandsDiscussed guiding policies from the 1995 Integrated Resources Plan (IRP)

Level of ServicePotential New Planning Objectives

Received input for the Water Efficiency Master Plan

October 24, 2019 Water Resources Planning 5

Meeting #1 – Thank you!Board Feedback Received Staff ActionsLevel of Service (LOS) GoalsBoard is willing to evaluate an 80% LOS as well as our current 90% LOS

Modeling 80% & 90% LOS to look at a wider range of cost-effective future planning scenarios

Potential New Planning ObjectivesResiliencyClimate ReadyFuture Ready / Enhances Flexibility

Including these potential objectives in discussion & evaluation of future planning scenarios

Water Conservation / Water Use EfficiencyContent with current level of programmingCost effective: ‘Conservation before Capital’

Provided feedback to Water Efficiency Master Plan (WEMP) team for customer saturation survey and WEMP development

Cost is a Top Priority & Interest Will continue to provide cost information for all analyses


Purpose of Second Workshop

1. Review and receive feedback on dry year groundwater usage constraints established in 1995 IRP

2. Review and receive feedback & direction for water reuse planning

3. Confirm feedback received to inform future planning-level analyses


Acronym KeyAHF = Above Hayward FaultARP = Aquifer Reclamation ProgramBHF = Below Hayward FaultDWR = California Department of Water Resources ECHO-SED = a set of water supply assumptions to be used until impacts of Bay-Delta Water Quality Control Plan implementation are knownIPR = Indirect Potable ReuseIRP = Integrated Resources Planmsl = Mean Sea LevelSGMA = Sustainable Groundwater Management Act


Tonight’s Dry YearGroundwater Discussion

General discussion only – no proposed operational changesIdeas discussed are only meant to inform planning-level modeling analyses of long-term water supply alternatives Changes to policy objectives & criteria would be pursued through a full Integrated Resources Plan update* with stakeholder engagement

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*Currently scheduled for 2025.October 24, 2019 Water Resources Planning

July WorkshopLevel of Service Goals (90% vs. 80%)Water Conservation Program

October Workshop (tonight)Use of Dry Year Groundwater ReservesWater Reuse Planning

IRP Components to Revisit in 2019


1995 IRP Components for Tonight

Policy Objectives

• “Environmental Impacts” – Avoid or mitigate

Evaluation Criteria

• “Protect Groundwater Resources” – Limit “Dry year groundwater mining” to -5’ msl

StrategyElements

• Quarry Lakes regrade; Newark Desalination Facility; Semitropic Bank; Recycled Water


Some Terminology and Definitions

“Dry Year Mining”Term used in IRP to describe dry year operation of pumping more water than is recharged within the year

Conjunctive Use Groundwater Management (Active)

Surplus wet-year water is stored for use in a dry yearACWD practices sustainable conjunctive use management whereby long term pumping demand is in balance with recharge


A Note on Changing Terminology

SGMA is sensitive to the term “mining”As a stand-alone term, “mining” suggests an unsustainable operationOur Policy Objective requires groundwater sustainabilityInstead of “Dry Year Mining” we will use the term “use of dry year reserves,”specifically referring to those in Niles Cone unless otherwise stated



Overview of Groundwater Planning and Operations

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Groundwater Resources Protection

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Key items evaluated in 1995 IRP:Salinity Barrier Wells Differing ARP and Potable production operations Desalination of ARP water Various hardness goals (vary by season or year-type; no goals at all)“Dry year mining” (as low as -40’ msl)

Evaluation Criteria



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1995 Recommendations:Abandon Salinity Barrier wellsBuild 8 mgd of desalination to recover discharged brackish water from ARP programVary ARP pumping with production wells150 ppm hardness year roundManage groundwater above +3’ mslLimit “dry year mining” to -5’ msl

Evaluation Criteria



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How we operate today: “Static” ARP rules (annual avg.) 10 mgd of Desal, operated more as a

production facility than a “recovery” facility Hardness 150ppm; flex during droughts or

other water management challenges Keep normal year levels above 10’ msl “Dry year mining” to -5’ msl

Evaluation Criteria


Groundwater Level Operating Conditions

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BHF Groundwater Level Operating Conditions

AHF Groundwater Level Operating Conditions


Question for tonight: Would the Board like staff to evaluate Planning Solutions that consider deeper cycling of Niles Cone?

Policy Objectives

• Avoid or minimize Environmental Impacts (i.e. must demonstrate sustainability)

EvaluationCriteria

• Protect Groundwater Resources: Allow use of dry year reserves below*-5’ msl

StrategyElements

• New Projects needed to implement? Possibly none*


*To be discussed further tonight & confirmed through additional analyses

Use of Dry Year Reserves

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ACWD’s existing criterion (-5’ msl) was evaluated in 1995 before:

Quarry Lakes regrade Desalination commissionedModeling could properly analyze benefits

“Clean up” intended to increase storageIRP recommended reevaluating this limit over time, once strategy elements are implemented and with better modeling

Evaluation Criteria


Sustainable Groundwater Management Act (SGMA)


Sustainable Groundwater Management Act (SGMA)

November 10, 2016: Groundwater Sustainability Agency July 17, 2019: Alternative to a Groundwater Sustainability Plan (Alternative) approved by the Department of Water Resources (DWR)

22Source: Department of Water ResourcesOctober 24, 2019 Water Resources Planning

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Alternative

Reflects existing recognized authority and framework for management of groundwater Continues the District’s existing groundwater

management practices and programs Preserves the successful sustainable

management already being performed by the District


Alternative Update Submitted for Re-evaluation by DWR every 5 yearsAlternative Update Due on January 1, 2022Areas Identified for Improvement in the District’s AlternativeDWR’s Recommended Actions

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Groundwater Model

UpgradeAlternative

Update

Alternative Update and

Model Upgrade Project

After an Alternative Has Been Approved


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SGMA and Sustainability

Undesirable ResultsSignificant and Unreasonable

SustainabilityGoal

Sustainable Yield

Sustainable Groundwater Management

• Achieved by 2040/42• Avoid Undesirable Results

October 24, 2019 Water Resources Planning Source: Department of Water Resources

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Seawater Intrusion Reduction

of GW Storage Lowering of GW Levels

Water Quality Degradation Land Subsidence Depletion of

Interconnected Streams

October 24, 2019 Water Resources Planning Source: Department of Water Resources

AHF BHF

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(Potential) Undesirable Results (Under Current/Foreseeable Ranges)

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Six Undesirable Results AHF BHFLowering of Groundwater Levels (Possible Declining Well Yield)

Yes No

Reduction of GroundwaterStorage

No No

Seawater Intrusion No Yes

Land Subsidence No No

Water Quality Degradation No No

Surface Water Depletion (Includes Impact Surface Water/GW Ecosystems)

No No


How do we currently avoid undesirable results?

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UndesirableResult

Sustainability Indicator Minimum Threshold

Below Hayward Fault (BHF)

Groundwater Levels in Indicator Wells

0 ft. MSL (default)-5 ft. rare, short-term

Groundwater Levels and Chloride Concentrations

Fresh water area: 250 ppm

Above Hayward Fault (AHF)Groundwater Levels 15 ft. presently;

future may be lower

In other words: Add enough recharge and don’t over-pumpOctober 24, 2019 Water Resources Planning

Groundwater Level Operating Conditions

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BHF Groundwater Level Operating Conditions

AHF Groundwater Level Operating Conditions


Sustainability Analysis

Programs that Ensure Sustainable Yield Artificial Recharge Integrated Planning and Operations Groundwater Monitoring Annual Reporting Conservation

Sustainable Yield has and will continue to be met


-80

-60

-40

-20

0

20

40

19351940194519501955196019651970197519801985199019952000200520102015

Elev

atio

n (ft

. NG

VD29

)

Year

1962 State Water

Project Deliveries

1974 Start of Aquifer Reclamation Program (ARP)

1964 Contract with San

Francisco

1961 ACWD Replenishment

Assessment Act

1972 Water level in the Newark Aquifer returned to above sea level,

1989 Rubber Dam #3 installed to improve recharge operations.

1993 Completed

Water Treatment Plant #2

1999 Completed

Quarry Lake Rehabilitation

Project

Historical BHF Indicator Well Water Levels and Milestones

2014 Construction

of Shinn Pond Re-

diversion 2 Pipeline


Planning and SGMA

Replenishment Assessment Act Integrated Resources Planning Study (1995,

2006, 2014) Urban Water Management Plans City General Plans District’s 25-Year Capital Improvement

Program


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Input Data

• Water Demand based on City General Plans

• All Groundwater Use• Water Year Type• Imported Water

Supply Availability• Other Local Supply

Integrated Resources Planning

• Used to Test Water Supply Initiatives, concepts, and operating scenarios

• Simulates Groundwater Supply Needs

Groundwater Model

• Verify Predicted Groundwater Storage

• Compare to Sustainability Criteria

Planning and SGMA (Cont’d)


Planning and SGMA (Cont’d)

• Alternative Update (Maintain Current Groundwater Operation Criteria)

2022

• Integrated Resources Plan Update

2025• Alternative

Update(Incorporate IRP Updates)

2027


Near Term Next Steps (Cont’d)

Continue implementing Alternative and submitting annual reportsGrant Application for Alternative Update and Model Upgrade ProjectAlternative Update Due on January 1, 2022Continue to coordinate with adjacent basinsOngoing coordination with planning efforts & IRP Update

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Submittal of Alternative to a

GSP(January 1, 2017)

Implementation of Alternative to a

GSP (Upon Submittal of Alternative)

Submit Annual Reports

(April 1 Each Year)

5-Year Alternative Update

(January 1, 2022)



Planning-Level Modeling of Future Scenarios

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Conceptual Example: 1987-1992 Drought / ECHO-SED

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Jan-85 Jan-90 Jan-95

Groundwater Level

Concept Baseline

SEA LEVEL

At -5’ supply is exhausted resulting in Shortages of 30%

With past IRP investments -we can fully recover within 3 years

Deeper cycling of Niles Cone, only 10% shortage, No new investments needed to achieve

Full recovery within the same period(Includes Fisheries bypass flows)


Use of Dry Year Reserves

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Increased use of dry year reserves could provide much of the benefits observed in other Water Supply InitiativesStaff recommends studying these options and adding them to the array of water supply initiatives for consideration

Evaluation Criteria


Discussion & Review:Confirm Direction



Recycled Water Planning & Direction

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ACWD has been evaluating Recycled Water since at least 19921995 IRP non-potable recommendation:

1,600 AF by year 20102,700 AF by year 2020Evaluate Potable Reuse in future as technology improves

Recycled Water PlanningStrategyElements


The 1995 IRP identified Recycled Water for several key reasons:

Displace demand for potable supplies with a new supply Frees up potable supply for banking in Semitropic for dry year useDisplaced production demand at potable water facilities Aided in District ability to meet 150 ppm hardness during peak months

StrategyElements

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Recycled Water Feasibility Studies

1993, 2000, 2003, 2010, and 2015


Recycled Water Feasibility Studies

Market AssessmentCurrent & Future Non-potable DemandsAssumed Increasing Future Demands

High Unit CostsHigher O&M Costs than Potable SuppliesCapital Costs to Build the Non-potable System


Recycled Water– Purple Pipe


Recycled WaterKey Factors Affecting “Future Demands”


0

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

4,500

$0

$1,000

$2,000

$3,000

$4,000

$5,000

$6,000

$7,000

$8,000

$9,000

$10,000

1990 1995 2000 2005 2010 2015 2020

Pote

ntia

l Yie

ld (A

F/yr

)

Year of Study

Unit Cost of Existing and Future Customers

Potential Recycled Water Customer Demand

Cap

italiz

ed U

nit C

ost (

2019

$/AF

)

50



Recycled Water – 2015/16 Study Advances in treatment technology Demonstrated safe reuse of treated wastewater Streamlined permitting Evaluated “Indirect Potable Reuse” (IPR)

Advanced Treatment Recharge Niles Cone Natural Filtration and Dilution Production as Potable Supply


The 2019 Joint ACWD/SFPUC/USD Purified Water Feasibility Evaluation in progress will consider this concept in greater detail

Recycled Water – 2015/16 Study Evaluated a

4,000 AF/yr. concept Compared to non-

potable, potable reuse has: Greater potential

yield Lower capital cost

(due to no non-potable distribution system)


Figure ES-5: Pipeline from WWTP to the Quarry Lakes

WWTP

Quarry Lakes

Recycled Water – Planning Recommendations

Given the present high cost and low-yield of a non-potable program, combined with the continued decline in demand for such water, it is Staff’s recommendation that:

1) The District’s vision for recycled water be focused on potable water reuse options.


Non-Potable Distribution System

The District contemplated use of “raw groundwater” in a non-potable distribution system as an interim measure until a recycled water source is developed.

Without a non-potable recycled supply future, concept benefits do not justify the cost and operating complexity that a non-potable system would create.


Recycled Water – Planning Recommendations

Given the present high cost and low-yield of a non-potable program, combined with the continued decline in demand for such water, it is Staff’s recommendation that:

1) The District’s vision for recycled water be focused on potable water reuse options.

2) The District no longer pursue the construction of a purple-pipe network to support a non-potable system.


Recycled Water – Next StepsContinue to assume recycled water is the District’s next source of supply, consistent with 1995 IRPComplete 2019 Joint Purified Water Feasibility EvaluationAs part of the District’s next Integrated Resources Planning (IRP) Study:

The District should continue to evaluate the potential timing for a future potable reuse project in the service area.


Workshop Wrap-Up & ConclusionsUse of Dry Year Groundwater Reserves

Water Reuse Planning


Next StepsAnticipated Spring/Summer 2020 Workshops

March 2020Water Efficiency Master Plan UpdatesReview planning strategies & modeling results

April 2020Preview 2020 Urban Water Management PlanOther planning topics

Additional Regular Board Meeting PresentationsAs needed



Thank you!

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2019-2020 water resources planning

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