using forecasted inflow to address rpm 3 - united states army

10440 Shaker Dr., Ste. 104 811 Mordecai Dr., Ste. 200

Columbia, MD 21046 Raleigh, NC 27604

410-715-0557 919-856-1288

HydroLogics, Inc. Office Locations

Advancing the management of water resources

Using Forecasted Inflow to Address RPM 3

Daniel P. Sheer, Ph.D., P.E.Megan W. Rivera, Ph.D.

Drought Provision Workshop on the Jim Woodruff Interim Operations Plan 13 December 2006

13 December 2006 2

Objectives

Introduce forecasting methodsGive an example of using forecasts to implement RPM 3Demonstrate the potential benefits of forecasts in alternative operations

13 December 2006 3

Mid Range Forecasting Techniques

Monthly serial correlation--HirschNWSRFS—Sacramento SMAMThese techniques do not rely on weather forecasts, only basin conditionsBoth produce information about shift in expected mean and variance of future inflows

13 December 2006 4

Provide highest minimum flow possible while refilling system by 6/1

WWR(flow) = Water required to maintain the flow at Woodruff90%

Water available = forecasted inflows90% - demands - IFrequirements- evap - voidWWR(flow) = Water available

13 December 2006 5

WWR(flow) using 90th percentile of historic inflows

Minimum supportable flow at Woodruff

0

500

1000

1500

2000

2500

5000 10000 15000

min flow (cfs)

Stor

age

need

ed to

su

ppor

t flo

w (k

af)

JanuaryAprilJulyOctober

13 December 2006 6

Calculating WWR(flow)

For a range of flows:Calculate difference between the desired flow and historic BI each day— this gives water needed from storage each day, if any Sum needed flows between now and June 1 to get required storage

13 December 2006 7

Determine Water Available and Maximum Supportable Flow

Forecast inflow to Lanier between now and June 1

Lanier used as a surrogate for system storage—when Lanier is full, the system is fullCurrently, using 90th percentile of forecasts

Subtract out volume needed for metro min flow requirement, local demands, evap, and refillUse graph to determine maximum supportable flow

13 December 2006 8

What can forecasts achieve?

A demonstration of alternative methodology …This has not been refined: we’re sharing an approach, not proposing a specific solutionSo we can compare apples to apples, the following are the same as the IOP in BiOp(IOP_23K_70_2RI)

2000 demandsMin Flows:

Atlanta = 750 CFS; Columbus = 1,850 CFS when WP > 621.6’,

1,200 CFS when WP < 621.6’Reservoir conservation pool rulesRamping rates for mussels

13 December 2006 9

Evaluation

BiOp figuresAdditional measure of sustained low flowsReservoir storage

Recreational impactPreserve water for future droughts

This is not a full evaluation, additional performance measures are needed

13 December 2006 10

Summary of Results: the demo run compared to IOP

Significantly better for musselsHigher flows for longer periods of time in 5 – 10k cfs range

More water in system storage/less recreation impactArguably better sturgeon habitatComparable floodplain connectivity

13 December 2006 11

Higher flows in critical range for mussels

BiOp 4.2.2.A Flow Frequency at the Chattahoochee Gage

0

2500

5000

7500

10000

12500

15000

65 70 75 80 85 90 95 100Frequency exceeded (% of days)

Dis

char

ge (c

fs)

10_20_O5BaselineRoRIOP

Demonstration of alternative methodology

13 December 2006 12

Fewer years with low flowsFigure 4.2.5.A

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

< 5000 < 6000 < 7000 < 8000 < 9000 < 10000

Discharge (cfs)

Freq

uenc

y(%

of y

ears

)



13 December 2006 13

More consecutive days of low flow in worst year: Consistent with RPM3

Figure 4.2.5.C

0

50

100

150

200

250

< 5000 < 6000 < 7000 < 8000 < 9000 < 10000Discharge (cfs)

Max

imum

con

secu

tive

# da

ys/y

r



13 December 2006 14

Fewer consecutive days of low flow in general: Consistent with RPM3

Figure 4.2.5.D

0

20

40

60

80

100

120

< 5000 < 6000 < 7000 < 8000 < 9000 < 10000

Discharge (cfs)

Med

ian

# da

ys/y

r



13 December 2006 15

Fewer occurrences of sustained low flows

Frequency of Sustained Low Flows 1975-2001

0

10

20

30

40

50

60

70

80

90

Baseli

ne RoR IOP

10_2

0_O5

Baseli

ne RoR IOP

10_2

0_O5

Baseli

ne RoR IOP

10_2

0_O5

Baseli

ne RoR IOP

10_2

0_O5

Baseli

ne RoR IOP

10_2

0_O5

Threshold / Flow Data

num

ber o

f tim

es fl

ow re

mai

ns b

elow

th

resh

old

for a

t lea

st 7

con

secu

tive

days

5000 cfs6000 cfs7000 cfs8000 cfs10000 Demonstration of alternative methodology

13 December 2006 16

More water in system storage

0 10 20 30 40 50 60 70 80 90 100Frequency Exceeded (% of days)

2500

2600

2700

2800

2900

3000

3100

3200

3300

3400

3500

3600

3700

3800

stor

age

(kaf

)

System Storage

Alt_Ops_10_20_O5 IOP


13 December 2006 17

More water in LanierLanier frequency of stages

1050

1055

1060

1065

1070

1075

1080

0 20 40 60 80 100% days stage exceeded

stag

e (ft

)

IOPHist10_20_O50initialimpactrestriction

initial

impact

restriction


13 December 2006 18

Slightly more water in West PointWest Point frequency of stages

620

622

624

626

628

630

632

634

636

638

640


stag

e (ft

)


initial

impact

restriction

13 December 2006 19

Still more water than historical in WF George

WF George frequency of stages

182

184

186

188

190

192

194

196


stag

e (ft

)


initial

impact

restriction


13 December 2006 20

Little Reduction of Total Sturgeon Habitat Days

BiOp 4.2.3.A Frequency of Spawning Habitat Availability

0

2

4

6

8

10

12

14

16

18

20

0 20 40 60 80 100Frequency exceeded (% of days)

habi

tat (

acre

s)

10_20_O5HistoricalRoRIOP


13 December 2006 21

Increase in sustained sturgeon habitat at RM 105

Max Habitat Sustained for at least 30 days during Spawning at RM 105

0.00

2.00

4.00

6.00

8.00

10.00

12.00

0 20 40 60 80 100Frequency exceeded (% years)

acre

s of

hab

itat



13 December 2006 22

Comparable Floodplain ConnectivityBiOp 4.2.6.A Frequency of Floodplain Connectivity to the Main Channel

During Growing Season

0

10,000

20,000

30,000

40,000

50,000

60,000

70,000

80,000

90,000

0 10 20 30 40 50 60Frequency exceeded (% of days)

habi

tat a

rea

(acr

es)



13 December 2006 23

What else is in the demo run?

Protect public health and safetyPreserve and enhance endangered species

Preserving endangered speciesIn demo run:

Mussels: 5000 cfs min and ramping rates as defined in IOPSturgeon: 6000 cfs min flow during spawning season

Sufficient storage must be reserved to meet these requirements in droughts

Enhancing endangered speciesIn demo run: provide the highest maintainable minimum flowBalanced with other project purposes

Other project purposesProject authorizations are interpreted by the USACE to determine relative priorities and balancing of benefits

13 December 2006 24

Protect Public Health and Safety

Reserve enough water to meet public health and safety requirements

Maximum system drawdown over a multi-year period to meet 2030 demands and minimum instream flows plus a margin of safetyDetermined by model runs

13 December 2006 25

Protect Endangered Species

Reserve enough water to maintain 5000 cfs and respect ramping rates over a multi-year period

13 December 2006 26

06/16/76 08/15/76 10/14/76 12/13/76 02/11/77 04/12/77 06/11/77Date

2000

2200

2400

2600

2800

3000

3200

3400

3600

3800

stor

age

(kaf

)

Carry-over Storages

system storage safety storage 5000 cfs stor

Safety and 5000 cfs carry-over storages

Safety storage

5000 cfs storage

Storage available for enhancement releases


13 December 2006 27

Releases made below Woodruff

Storage available for enhancement releases is managed to avoid the last two cases for the entire historical record

No requirementSystem storage < safety storage

5000 cfsSystem storage > safety storage

Enhancement releases = max supportable flow

System storage > 5000 cfscarry-over

Releases needed to maintain flood protection

System storage > full

13 December 2006 28

Managing storage available for enhancement

Maintain maximum supportable flow, but no more than 10,000 cfsRationale

No apparent value to musselsIncrease in sturgeon spawning habitat levels off at 10,000 cfs

Effect on spawning habitat shown on the next slides

13 December 2006 29

Relationship between habitat and flow

Flow (cfs)

Hab

itat (

acre

s)

13 December 2006 30

Overall Spawning Season Flows are close to historical and IOP

Spawning Season Flow Frequency at the Chattahoochee Gage

0

50000

100000

150000

200000

250000


Dis

char

ge (c

fs)

10_20_O5BaselineIOP


13 December 2006 31

Infrequent flows are lower, but …Spawning Season Flow Frequency at the Chattahoochee Gage

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

20000


Dis

char

ge (c

fs)

10_20_O5BaselineIOP


13 December 2006 32

… the difference in total habitat is small

BiOp 4.2.3.A Frequency of Spawning Habitat Availability

8

10

12

14


habi

tat (

acre

s)



13 December 2006 33

… the difference in habitat at RM 105 is even smaller

Frequency of Spawning Habitat Availability at RM 105

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5


habi

tat (

acre

s)



13 December 2006 34

… and there is more sustained habitat at RM 105

Max Habitat Sustained for at least 30 days during Spawning at RM 105

0.00

2.00

4.00

6.00

8.00

10.00

12.00

0 20 40 60 80 100Frequency exceeded (% years)

acre

s of

hab

itat



13 December 2006 35

This is because of the relationship between habitat and flow

Flow (cfs)

Hab

itat (

acre

s)

13 December 2006 36

Results can be counter-intuitive

The sturgeon habitat results highlight the importance of evaluating operations based on performancerather than volumes of waterA full range of performance measures is needed

13 December 2006 37

Conclusion

Using forecasted inflows in conjunction with current storage to implement RPM 3 can identify the largest minimum flow that will not compromise next year’s flows.Implementing RPM 3 in a manner similar to the implementation in the demo run will provide significantly more benefits to all users. The operating rule used in the demo run can be further improved

Consider other performance measuresConsider other factors in determining Woodruff releasesReservoir balancingOptimize parameters

10440 Shaker Dr., Ste. 104 811 Mordecai Dr., Ste. 200

Columbia, MD 21046 Raleigh, NC 27604

410-715-0557 919-856-1288

HydroLogics, Inc. Office Locations

Advancing the management of water resources

Thank You!

using forecasted inflow to address rpm 3 - united states army

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