Overview of Proposed Water Supply ProgramMarch 9, 2021

Agenda

Water Supply History and Planning Efforts

Program Purpose and Need

Program Elements Considered

Recommended Program

Program Timeline

Financial Evaluation of Proposed Program

Next Steps

2

Water Supply History and Planning Efforts

Groundwater Supplies

The Waldorf Water System is supplied

by 16 groundwater wells

As population has grown, new wells

were drilled into deeper aquifers

The effect of water withdrawals on the

aquifers has been studied for nearly 40

years

Charles County has worked with MDE

to balance withdrawals with aquifer

recharge to minimize drawdown

3

reprinted from Staley, 2015

Water Supply History and Planning Efforts

Groundwater Supplies

Drawdown is the change in water level

caused by pumping

Drawdown can be controlled by:

• shifting withdrawals between

aquifers (as permitted by MDE)

• considering alternative water

sources

• minimizing demands for finished

water

• conservation measures

• water reuse

4

Charles County Water Resources

Overview Presentation, 2011

Water Supply History and Planning Efforts

WSSC Interconnection

Drawdown Management Efforts

5

Alternative water supply efforts

• Developed Agreement for Supplemental Water Supply from WSSC in 1987

• Started utilizing the supply in 2009 (up to 1.4 MGD)

Non-potable reuse efforts

• PANDA Power Plant started use of treated effluent in 1996

• CPV Power Plant started use of treated effluent in 2017

Water conservation efforts

• Formed Water Resource Advisory Committee in 2005

• Introduced a “Tiered Rate Water Bill Structure” to encourage conservation in

2010

Water Supply History and Planning Efforts

Ongoing Planning Efforts

6

Water Resources Advisory Committee (WRAC) formed in

late 2005

Members

•County Staff

•Town Staffs

•County Health Department

•MDE

•Well Drillers

•Small Water System Operators

Recommendations provided to County Commissioners in 2006

Strategic Plan issued in 2011

Water Source Feasibility Study

completed in 2018

Reviewed recent groundwater usage and aquifer data

Developed demand forecasts

Developed alternatives and performed Triple Bottom Line evaluation

Water Supply Program efforts initiated in 2019

Water Resources Roadmap initiated in 2019/2020

WSSC water supply agreement discussions initiated in 2020

Currently working with MDE on renewing Groundwater Appropriation Permits and approval of alternative water sources

Program Purpose and Need

• Provide long-term water supply reliability for the Waldorf and Bryans Road systems

• Balance economic, social and environmental objectives

• Provide opportunities for potential water supply regionalization

Purpose of the Water Supply Program

• Changes in reliability of groundwater supplies

• MDE groundwater appropriation considerations

• Projected growth in population and employment

Need for the Water Supply Program

7

Program Elements Considered

Initial Screening of Alternatives

Surface Water Options

• Upper / Lower

Reaches Potomac

River

• Patuxent River

• Riverbank Filtration

• Other Surficial

Withdrawals (e.g.,

power stations)

Groundwater Options

• Surficial Aquifer

Wellfield

• Aquifer Storage and

Recovery

• New Wells in Magothy,

“Down-Dip” Lower

Patapsco or Patuxent

Aquifers

Other Options

• Indirect and Non-

Potable Reuse

• Increased WSSC

Supply

• Wellfield Management

Plans

• Water Efficiency

Programs

8

Program Elements Considered

Patuxent River adjacent to Charles CountyLower reaches Potomac River adjacent to

Charles County

Upper reaches Potomac River adjacent to

Charles County

River Withdrawal-Based Surface Water Options

9

Program Elements Considered

Riverbank Filtration and Potential Indirect Potable Reuse Options

10

Examples of riverbank filtration wells – horizontal

collector (Ranney) well (left) and vertical well (right)

Membrane-based indirect potable reuse treatment

train

Ozone / BAF / GAC indirect potable reuse treatment

train

Program Elements Considered

Final Round Scenarios

Scenario 1: Increased Allocation from WSSC

Scenario 2: Upper Reaches Potomac River

Scenario 3: Potomac River + WSSC

Scenario 4: Managed Aquifer Recharge + WSSC

Scenario 5: Increased Groundwater + Surficial

Wellfield + WSSC

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*

Recommended Program

12

Short Term

Additional 2 - 6 mgd from

WSSC

• Early implementation of

distribution upgrades

• Full implementation by 2026-2027

Long Term

Potomac River Supply

• 5-10 mgd

• Timing likely extends past

2031

GW Near Term

Filling the gap until

short-term plan is

implemented

Recommended Program

Planned Activities Reflect Interconnected Program Elements

13

Initiate MDE GW

Appropriations

Process

Informs potential

need for greater

WSSC Water supply

near-term

Implement new

well(s) and / or

increased withdrawals

from existing wells

Additional flow

available and in-use

Initiate Discussions

with WSSC Water

• Supply availability / reliability

• Water quality and quantity

• Required infrastructure

• Timeline

Plan for and

Implement

Infrastructure

• Pipelines

• Water quality and treatment

• Operational planning

Potomac River

Supply Concept

Refinement

• Intake / plant siting

• Initial regulatory

coordination

Continue Long-

Term Water Quality,

Treatment and

Permitting Efforts

Consider source salinity in

conjunction with groundwater

and WSSC supply operations

GW Near Term Short Term Long Term

Recommended Program

Conceptual Infrastructure Plan

14

Program Timeline

Planning and Near-Term

15

MDE Permitting Needs

Financial Evaluations

CIP Planning

+

Program Timeline

Short-Term

16

Hydraulic Evaluation

Water Quality Evaluation and

Blending Scenarios

Agreement Negotiation

Early Implementation of

Distribution Upgrades

New Connection Implementation

+

Program Timeline

Long-Term

17

Natural and Historic Evaluation

Water Quality and Salinity Evaluation

and Analysis

Intake Location and Plant Selection

Alignment Studies and Easements

MDE Permitting

Process Selection/Piloting

Implementation of Treatment and

Distribution

+

Financial Evaluation of Proposed Program

Projected Capital Costs of Program Components

18

$27.7 $27.5

$122.0

$57.9

$0

$20

$40

$60

$80

$100

$120

$140

Expanded WSSCInterconnection -

Distribution

Expanded WSSCInterconnection -

Treatment

New Potomac WTP DistributionImprovements for New

Potomac WTP

Mill

ion

s$236M

Total Program

Costs

Financial Evaluation of Proposed Program

Estimated Contribution to Quarterly Bill Amount and Quarterly Rate Increase by Fiscal Year (FY22 – FY35)

19

Next Steps

20

MDE Permit

• Continue development of documentation to support interim MDE Groundwater Appropriations

• Consider opportunities to partner on Regional Water Supply

• Obtain Groundwater Appropriation permit and identify permit term

WSSC Supply

• Execute MOU with WSSC Water for Water and Sewer Agreement Changes

• Secure amendment to the 1987 Water Supply Agreement

• Initiate detailed project planning and design

• Continue to evaluate water quality and treatment needs

Overview of Proposed Water Supply Program