Lake Murray Dam flows and striped bass spawning in Congaree River

Objective

• Consider Congaree River striped bass flow needs in Lake Murray dam license

– Importance

– Biological needs

– Affect of Flow and Temperature

• i.e. it is ‘under the influence’ of the dam

– DNR recommendation

– Questions/Discussion

LakeMurray

LakeWateree

LowerSaluda

River LakeMarion

LakeMoultrie

Importance of Striped Bass

• State Fish of SC

• Initial inland population

• Aquaculture developed

• Economic, recreational -$260 million

• Representative migratory species

• Well-studied

• Santee-Cooper population collapse

84 86 88 90 92 94 96 98 00 02 04 06

Year

Ab

un

dan

ce

> 2 years old

Total catch

Striped Bass Abundance

18” 5/day

21”

5/acre 15/acre

4/1/06 8/1/06 12/1/06 4/1/07 8/1/07

Syste

m K

M

-50

0

50

100

150

200

250Fish 3508

Date

Syste

m K

M

-50

0

50

100

150

200

250Fish 3517

Cong-Wat Confluence

Sal-Broad Confluence

Pinopolis Dam

Diversion Canal

Cong-Wat Confluence

Sal-Broad Confluence

Pinopolis Dam

Diversion Canal

Watere River

Cooper River

Santee River

Broad River

Saluda River

Congaree River

Lake Marion

Lake Moultrie

• > 80% of spawning in Congaree River

• Most spawning from CNP to I-77

•Peak spawning in April through mid-May

0

5

10

15

20

25

0 10 20 30 40 50 60 70 80 90 100

Ave

rage

dai

ly T

em

pe

ratu

re

Date - where '1' is March 1 and '92' is May 31.

Broad

Sal Cola

Sal Dam

0

50

100

150

200

250

300

0 5,000 10,000 15,000 20,000 25,000 30,000

Rec

ruit

men

t o

f ag

e-2

str

iped

bas

s

Average April discharge (cfs)

Average LSR contribution

• LSR @ Cola, 1926-2007

– Mean annual flow = 2,749 cfs

• Congaree R. @ Cola, 1956-2007

– Mean annual flow = 8,872 cfs

• By subtraction, mean flow in Broad = 6,123 cfs

• LSR supplies, on average, 31% of Congaree River flow

• LSR mean flow is 45% of Broad’s mean flow

DNR recommendation

• Period of concern is April 1 through May 10

• Assume base minimum flow is 1,300 cfs

• No flow augmentation when Broad > 7,700

• On a continuous basis each ‘day’, release into LSR– 45% of previous days flow within Broad, OR

– the release needed to reach 9,000 cfs in Congaree (whichever is lower)

• No augmentation needed when Broad < 2,700

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

0 10 20 30 40 50 60

Flow, cfs

Broad R. flow

Lower Saluda flow

Congaree R. flow