What does it mean?

Jon S. Albright Freese and Nichols, Inc. WATER FOR TEXAS 2017 Texas Water Development Board January 23-25, 2017

Topics

• What is a drought of record (DOR)?

• How is the DOR used quantify water supplies?

• How to identify new DOR conditions?

• What regions potentially have a new DOR?

What is a DOR?

• The historic period of record for a watershed in

which the lowest flows were known to have

occurred based on naturalized streamflow (30

TAC §297.1).

• The period of time when historical records

indicate that natural hydrological conditions

would have provided the least amount of water

supply (31 TAC §357.10).

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

19

40

19

44

19

48

19

52

19

56

19

60

19

64

19

68

19

72

19

76

19

80

19

84

19

88

19

92

19

96

20

00

20

04

20

08

20

12

An

nu

al F

low

Mill

ion

s

How is the DOR used quantify water supplies?

Firm Yield--Maximum water volume a reservoir can

provide each year under a repeat of the Drought of

Record using anticipated sedimentation rates and

assuming that all senior water rights will be totally

utilized and all applicable permit conditions met (31

TAC §357.10).

0%

20%

40%

60%

80%

100%

120%Ja

n-4

0Ja

n-4

2Ja

n-4

4Ja

n-4

6Ja

n-4

8Ja

n-5

0Ja

n-5

2Ja

n-5

4Ja

n-5

6Ja

n-5

8Ja

n-6

0Ja

n-6

2Ja

n-6

4Ja

n-6

6Ja

n-6

8Ja

n-7

0Ja

n-7

2Ja

n-7

4Ja

n-7

6Ja

n-7

8Ja

n-8

0Ja

n-8

2Ja

n-8

4Ja

n-8

6Ja

n-8

8Ja

n-9

0Ja

n-9

2Ja

n-9

4Ja

n-9

6

Pe

rce

nt

Full

Firm Yield Analysis

0%

20%

40%

60%

80%

100%

120%

Jan-50 Jan-52 Jan-54 Jan-56 Jan-58 Jan-60

Pe

rce

nt

Full

Drawdown over Entire 50s Drought

June 1950 to May 1957

0%

20%

40%

60%

80%

100%

120%

Jan-50 Jan-52 Jan-54 Jan-56 Jan-58 Jan-60

Pe

rce

nt

Full

Drawdown Later in 50s Drought

May 1953 to June 1957

0%

20%

40%

60%

80%

100%

120%Ja

n-9

7

Jan

-99

Jan

-01

Jan

-03

Jan

-05

Jan

-07

Jan

-09

Jan

-11

Jan

-13

Jan

-15

Pe

rce

nt

Full

Long Response

March 1998 to June 2016

How to identify new DOR conditions?• Comparison of drawdowns

• Gage flows

• Forecasting and modeling

0%

20%

40%

60%

80%

100%

120%

0 100 200 300 400 500 600 700

Pe

rce

nt

Full

Days into Drought

Comparison of Historical Drawdown Periods

Drought 1 Drought 2

0

100

200

300

400

500

600

700

800

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

Cu

mu

lati

ve F

low Th

ou

san

ds

Months of Drought Conditions

Comparison of Cumulative Flows

50s Drought Recent Drought

0

20

40

60

80

100

120

140

160

180

200Ja

n-1

1

Jun

-11

No

v-1

1

Ap

r-1

2

Sep

-12

Feb

-13

Jul-

13

Dec

-13

May

-14

Oct

-14

Mar

-15

Au

g-1

5

Jan

-16

Jun

-16

No

v-1

6

Ap

r-1

7

Sep

-17

Feb

-18

Jul-

18

Dec

-18

Sto

rage

(ac

-ft)

Tho

usa

nd

s

Forecasting – Repeat Worst Drought

Historical Repeat 2011 No Inflow

0

20

40

60

80

100

120

140

160

180

200

Jan

-11

Jun

-11

No

v-1

1

Ap

r-1

2

Sep

-12

Feb

-13

Jul-

13

Dec

-13

May

-14

Oct

-14

Mar

-15

Au

g-1

5

Jan

-16

Jun

-16

No

v-1

6

Ap

r-1

7

Sep

-17

Feb

-18

Jul-

18

Dec

-18

Sto

rage

(ac

-ft)

Tho

usa

nd

sForecasting – Selected Drought Periods

Historical Mar-51 to Feb 56 Mar-77 to Feb-82 Mar-11 to Dec-13

0

50

100

150

200

250Ja

n-1

1

Jun

-11

No

v-1

1

Ap

r-1

2

Sep

-12

Feb

-13

Jul-

13

Dec

-13

May

-14

Oct

-14

Mar

-15

Au

g-1

5

Jan

-16

Jun

-16

No

v-1

6

Ap

r-1

7

Sep

-17

Feb

-18

Jul-

18

Dec

-18

Sto

rage

(ac

-ft)

Tho

usa

nd

s

Forecasting – Risk Analysis (CRA)

Stage 2 Trigger

Stage 3 Trigger

Stage 4 Trigger

Normal - Dry

Dry

Very Dry

Stage 1 Trigger

Wet

Top of Conservation

Potential new DOR (partial listing)

Jon S. AlbrightFreese and Nichols, Inc.

jsa@freese.com817-735-7267