Citizens Advisory Committee

State College, Pennsylvania

August 13, 2004

• Historic highs: 9 million tons per year

• Current transported load: 3.1 m/tons

• Lower Susq dams: 50-70% trapping efficiency

• Net delivered load to Bay: .9 to 1.1 m/tons

• Net delivered load 1985: 1.178 m/tons

• Net delivered load 2002: 1.060 m/tons

Susquehanna Sediments

Holtwood Dam

Conowingo Dam

Safe Harbor Dam

3,100,000 tons sediment

75,000 tons nitrogen

4,350 tons phosphorus

2,210,000 tons sediment (70%)

1,500 tons nitrogen (2%)

1,740 tons phosphorus (40%)

890,000 tons sediment

73,500 tons nitrogen

2,610 tons phosphorus

AVERAGE ANNUAL

INPUT TO RESERVOIR SYSTEM

AVERAGE ANNUAL

AMOUNT TRAPPED IN

RESERVOIR SYSTEM

AVERAGE ANNUAL

OUTPUT TO CHESAPEAKE BAY

70%

40%

2%

SEDIMENT

NITROGEN

PHOSPHORUS

Percentage trapped in reservoir system:

0 6 0 , 0 0 01 0 , 0 0 0 2 0 , 0 0 0 3 0 , 0 0 0 4 0 , 0 0 0 5 0 , 0 0 0

D I S T A N C E U P S T R E A M F R O M C O N O W I N G O D A M , I N F E E T

5 0

4 0 0

1 0 0

1 5 0

2 0 0

2 5 0

3 0 0

3 5 0

VE

RT

IC

AL

C

RO

SS

-S

EC

TI

ON

AL

A

RE

A,

I

N

SQ

UA

RE

F

EE

T

(´

1,

00

0)

E

A P P R O X I M A T E L E V E L O F

R E M A I N I N G S T O R A G E C A P A C I T Y

M A X I M U M S E D I M E N T - S T O R A G

C A P A C I T Y

1 9 2 8

1 9 5 9

1 9 9 0

1 9 9 3

1 9 9 6

SEDIMENT DEPOSITION

0

• Conventional estimate 17-20 years

• With assumptions: 20-30 years1. 10% decrease in transported load2. Statistically expected scour3. Trapping efficiency of 60%

Storage Capacity Status

• Bay-wide: 5.8 m/tons

• Susquehanna: 1.2 m/tons (20%)

• James River: 1.3 m/tons (22%)

• Potomac: 2.0 m/tons (35%)

1985 Sediment Loads

• Bay-wide: 4.15 m/tons

• Susquehanna: 0.96 m/tons

• James River: 0.94 m/tons

• Potomac: 1.49 m/tons

2010 Cap Load Allocations

• C2K: “By 2003, work with the SRBC and others to adopt and begin implementing strategies that prevent the loss of the sediment retention capabilities of the lower Susquehanna River dams.”

• Pennsylvania tributary strategy: 1.1 m/tons with full implementation

Moving Forward

• Reservoir feasibility study

• What about the wild cards?- scour- episodic nature of precip- flow and bank loss - system storage and the great purge

• Stay the course, but manage expectations

Lingering Issues

The Water Quantity-C2K

Connection:

The Implications of Flow for Water Quality and Vital Habitat

Protection and Restoration

Basin Overview• 27,510 square mile

watershed.

• 32,000+ miles of streams.

• Normal Flow of Susquehanna River is 18 million gallons per minute at Havre de Grace, MD.

• Susquehanna River is largest tributary to Chesapeake Bay.

• Population of 4.2 million

Project Review Regulations

• Consumptive Water Use > 20,000 gpd

• Surface-Water Withdrawals > 100,000 gpd

• Ground-Water Withdrawals > 100,000 gpd

Surface-Water Withdrawals

• Regulatory threshold; 100,000 gpd

• Protection of instream/downstream uses

• Conservation releases

• Passby flow requirements

• Cold water fisheries – IFIM analysis

• Warm water fisheries – 20 % ADF

Groundwater in the Susquehanna Basin

• Nearly 69 billion gallons. • Most of the potable water is within 300 ft of

ground surface.• Groundwater supplies stream flow, upwards

of 90% of base flow during extended droughts.

• Withdrawing groundwater results in about a 1-to-1 reduction in flow downstream.

Drought Years19919911

19919955

19919977

19919988

19919999

20020022

Groundwater in the Susquehanna Basin

• Over 50% of the basin’s population uses groundwater for water supply

• To date, SRBC has approved the withdrawal of more than 232 million gpd of groundwater.

Groundwater Use in the Susquehanna Basin (1995

data)

• Water Supply 195 mgd = 50%• Mining 90 “ = 23% • Industrial 48 “ = 12% • Agriculture 42 “ = 11% • Other 16 “ = 4%• Total 391 mgd

Ground-Water Withdrawals

• Regulatory threshold; 100,000 gpd

• Avoid impacts to resource and other users

• Pump test guidance

• Ground-water availability analysis

• 48-hour constant-rate pump test

Consumptive Water Use

• Regulatory threshold; 20,000 gpd

• Water used and not returned to the basin

• Out-of-basin diversions

• Compensation requirements

Compensation Options For Consumptive Water Use

• Discontinuance

• Releases from storage

• Payment into the Water Management Fund

• 30,000 acre/ft of pooled water storage

PEAK CONSUMPTI VE WATER USE I N THE SUSQUEHANNA RI VER BASI N

0

100

200

300

400

500

600

700

800

1970 1990 2020

YEAR

JUL

Y T

OT

AL

CO

NS

UM

PT

IVE

US

E (m

gd

)

STREAM FLOW AND CONSUMPTI VE USE

SUSQUEHANNA RI VER BASI N

0

5

10

15

20

25

30

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC

PE

RC

EN

T

MO. CONSUMPTIVE USE AS % OF YEARLY TOTAL

MIN. MEAN MO. DISCHARGE AS % OF YEARLY TOTAL

Past, Present and Projected Consumptive Use as a Percentage of Susquehanna River Historic Low Flow

(1250 mgd)

Additional Consumptive

Use up to 2020

Additional Consumptive

Use up to 1990

Consumptive Use up to 1970

Remaining Flow

(22%)

(56%)

(36%)

Moving Forward

• Warm Water IFIM

• Groundwater Management Plan

• PA Act 220 State Water Plan

• Water Budgeting

• Protected Area Designations