Basin Hydrology, 

Water Years 2018-2019 

Operations 

Glen Canyon Technical Work Group

June 25, 2018

<•~!U"!N' 0, !Hf INr 

•·• :::_ U.S. Department of the Interior 

•· .. ~;;;.;,,.-./ Bureau of Reclamation 
Snow Conditions

2

SWE peaked at 73 % 

of the peak seasonal 

median on 3/30/2018

Snowpack has melted out

Updated on 6/22/2018

24 

22 

20 

18 

16 

14 

12 

10 

8 

6 

4 

2 

0 

(\ 

't av 

(\ 

~ 

~o 

Upper Colorado River Basin Snotel Tracking 

Aggregate of 104 Snotel Sites in the Upper Colorado River Basin 

(\ 

cf ()<Q 

.. .. .. . .. .. . .. .. . ,~ . ~· . ,.. . ~~ 

Month 

125 W 

100 

~ 

"" "' &: 

"' C 

0 

I 

V) 

75 C 

"' '5 

., 

:E 

0 

50 ill, 

i¥ ., 

!:! 

., 25 ll. 

- comparison Year Basin-wide S1NE W\'2017 - current Year Basin-wide SVI/E W\'2018 - 30 Year Basin-wide Median S1/1/E I 

Data Provided by the Natural Resource Cons.rvation Service {NRCS} 

RECLAMATION 
1

-Ocl 

15-0ct 

29-0ct 

12-Nov 

Flow Rate, cfs 

~ ~ ~ N 

._Ln p ~· .p .y, 

0

8 8 8 g 8 0 C O O 0 

26-Nov 

1

~ it I I 

10-Dec -.ai~ t ~ ?/ t I a, 

0 

~ 24-Dec "-~ ,I t I -

("") 

~ I I .....a. 1 I ~ 

7-Jan 

21-fan - I .I -1..;._; I ! ~ ~ tD 

4-Feb ~ 1, C' t I Cl> "'tJ 

~ 0 

18-Feb ,a t I ; ::: 

4-lvlar ~ =-if.• t E .L t I ~ !'.!!,. -II> - 18-Mar -•lliii-- I -~ I I 

1-Apr ' ) , - iiiii• I C t I ! 

ro 

15-Apr J· ,2 · 1 · · :S.. t I ~-

o 

29-Apr ii .... !!'""' ,..::::== I I ::I 

13-M ay 

27-M ay 

10-.lun 

24-Jun w w w ~ ~ ~ ~ w 

~ ~ ~ ~ ~ ~ ~ i ~ 0 ~ ~ ~ ~ ~ 0 Elevations. feet 
4

94%

59%

53%

70%

88%

1 percent of average based on period 1981-2010.

https://www.usbr.gov/uc/water/basin/index.html

Reservoir

A-J 

Forecast

(KAF)

Percent 

of 

Average1

Fontenelle 980 135%

Flaming Gorge 1,100 112%

Blue Mesa 260 39%

Navajo 174 24%

Powell 2,650 37%

Basin Storage

As of 

6/24/2018

Upper Basin Storage

2018 April to July 

Inflow Forecast

Issued June 18, 2018
5

June Mid-Month: 2.65 maf (37%)

18 

" A~ril - Jul~ 2018 Forecast " -

u. 

4; 16 

== 

Most Prob: 3.0 maf (42%) 

Min Prob: 2.08 maf (29%) 

-Cl) 

14 E 

::::I 

" M ax Prob: 4.18 maf (58%) 

" 

~ 12 

~ ;: - - C 10 

- - "Cl - Cl) 

.!!! - 8 ::::I - - - - Cl 

Cl) 

.. 

C 

::, 6 " - - +- -- - -

>, " 

- - - .., 

'3 - 4 I 

-·::::: 

Q. 

<( 2 . -

... 

0 

'SI" 

<D 

O') 

<D 

<D 

J> 

00 

<D 

O') 

0 

..... 

O') 

N 

rO') 

'SI" 

rO') 

<D 

..... 

O') 

00 

rO') 

- - - - - - - -

Lake Powell Unregulated Inflow 

April - July 2018 Forecast 

Issued June 4th 

-

- - Average: 7.16 maf (1981-2010) 

- - - - -- - -

- - - - •• -

- - - -- - - - - - - - - - - - -

~ 

0 N 'SI" <D 00 0 N 'SI" <D 00 0 N 'SI" <D 

00 00 00 00 00 O') O') 0) O') 0, 0 0 0 0 

O') O') O') O') O') O') O') O') O') O') 0 0 0 0 

- - - - - - - - - - N N N N 

Year 

-

-

- - -- - -

- -

- -

00 0 N 'SI" <D 00 00 

0 - ~ 

0 0 0 0 - 0 - 0 - 0 - N N N N N N N 

C: t; X ·- 0 «:S 

~ ::E ~ 
6

Lake Powell 2018 Operating Tier

Upper Elevation Balancing

• Tier was set in August 2017

– Start with 8.23 maf release

• Use April 24-Month Study 

projections of end of water 

year storage to potentially 

adjust

1. Stay with 8.23 maf

2. Balancing: 8.23 - 9.0 maf

3. Equalization: > 8.23 maf

3,700 

3,63; -31666 

(2COO-Ki25) 

3,676 

3,490 

3,370 

M th@ lntt11im Gui!tflliria~ 

Equaililation Tier 

Equalize, t:\~io spi Is 

or release 8.23 maf 

-----------------------------------------------

Upper Elri1111icn 

Balancing Tier 

t-iel1:::ase 8.23 rmll, 

11 L• k• M,-;~ < 1,0•) 1,., 

l,al<11l0e, oonterrts witil 

.: min/ma:< '= ease of 

10 Md9.C ITl~f 

Mld·Ele•aJ Ion 

Release Tier 

R.:-lcasc 7,4S maf. 

H ake Mead< 1.:>Z5 feet 

reltat.e 8.23 m.if 

Lower E!c\'alion 

Balancing Tier 

Balance contentr. with 

a min/max 'E ease of 

103nd ~.E rn3f 

16.0 -19.3 

('20M-2C26) 

9.6 

5.9 

,.o 

0 
7

Potential Lake Powell Release Scenarios 

Water Year 2018 Release Volume as a Function of Unregulated Inflow Volume 

based on June and April 2018 24-Month Study Conditions I I 

Water Vear 2018 

Powell releases controlled by ba lancing 2018 Most Probable 

9.5 contents of Powellseμ,o and Meadsev:;o WY Unreg Inflow= 5.25 mat (48%) 

(Release= 8.23 up to 9.0 maf) Powell Release= 9.0 maf 

9.0 

8.5 

YTD Measured Unreg Inflow = ·---, ______ .. / ,,,,,,,,' 

4.4 mat (WY18 as of 6/24/18) ... ,,,,,,,,-✓• 

- -

I • . -. , __ 

' \\ ----------------- ' ' ' 2018 MaKimum Probable \\ 

I ' WY Unreg Inflow = 7. 76 mat (72%) -

M inimum Inflow Scenario Powell Release= 9.0 maf 

WY Unreg Inflow = 4.32 mat (40%) 

Powell Release= 9.0 mat 

8.0 - coordinated Ops Main Line I0 Probable Max {Apr 18) 

7.5 

O Probable Min (Apr 18) 

• Most Probable (Jun 18) 

• WY Unreg Inflow (to date) 

7.0 

0 2 4 6 8 10 

Potential Water Year Unregulated Inflow Volume (maf) 
8

1,600 

1,400 

1,200 

C 

ro 

-"' 

~ 1,000 

QJ 

E 

::, 

0 

> 800 

QJ 

(/) 

ro 

QJ 600 © 

0::: 

400 

200 

Projected Lake Powell Monthly Release Volume Distribution 

Release Scenarios for Water Year 2018 

Based on June and April 2018 modeling 

WY 2018 Release Scenarios 

Apr Probable Min: 9.0 maf 

Jun Most Probable: 9.0 maf 

Apr Probable Max: 9.0 maf 

G40 630 

8bU 

C 

ro 

--, 

..Q 

QJ 

LL 

llOO 

(0 

705 705 

(0 

• Probable Min • May Most Probable • Probable Max 
9

Water Year 2018 projections

Most: 9.0 maf release

MIN: 9.0 maf release 

MAX: 9.0 maf release 

End of May 2018 Elevation:

3611.0 feet (53% full) End of CY 2018 Projection:

3588.5 feet (44% full)

Min/Max Range: 3580 to 3612 feet

Water Year 2019 projections

Most: 9.0 maf release

MIN: 8.8 maf release 

MAX: 9.0 maf release 

3,700 

3,675 

3,650 

3,625 

= -; 3,600 

0 

~Cl): 3 575 

. jjj 

3,550 

3,525 

3,500 

3,475 

I I 

Lake Powell End of Month Elevations 

Historic and Projected based on June and April 2018 Modeling 

Equalization Tier (ET) 

Upper Elevation Balancing Tier (3575'-ET) 

I I I Fi.Jtl re ·~ 

3,154 3,655' 

, 

, 

, 

, I - - L I ~

,._1 i 

/ -==L-- . r---1---rl - ---

I I I 

Mid-Elevation Release ner (3525'-3575') 

Lower Elevation Balancing Tier (<3525') 

i,..,. ... _ - w-..._ .. 

.. .. ~--..._ __ ._ __ -.. ...... _ ,' .... ... _., __ .. ~-

, 

, 

, 

--......... , 

---r-_:;;, ~ 

• I I I I 

... 

--

I 

, ,,, 

-- ;~~ P;; e; P~ol -1---13,i90: -t---' -, ----------------------1-1-1-. ' ' ' ' I ' ' 

I'-- I'-- I'-- I'-- r-. I'-- I'-- I'-- I'-- r-- I'-- I'-- co co co co co co co co co co co co a, a, a, a, a, a, a, a, a, ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 

' o!. o!. >- . c, a. t5 > l) ' o!. ' >- C: . c, 6. t5 l) • o!. ' >- C: C .Q C • c, 6. :::, C .Q ~ 

:::, > C .Q ~ :::, (!l Q) '" a. «I :::, :::, Q) 0 Q) (!l QJ cu a. «I :::, :::, Q) 0 Q) (!l Q) cu a. 11) :::, :::, Q) -, LL ~ <( ~ -, -, <( (/) 0 z 0 -, LL ::1; <( ~ -, -, <( Cl) 0 z 0 -, LL ::1; <( ~ -, -, <( Cl) 

--Observed --June 2018 Most Prooable - - -Apr 2018 Mi1 Probable • --• Apr 2018 Max Probable 
10

Most Probable End of CY 2018 

Projection: 1,077.7 feet (38% full)

Min/Max Range: 1,077 to 1,081 feet

Most Probable End of CY 2019 

Projection: 1,073.3 feet (36% full)

Min/Max Range: 1,062 to 1,079 feet

1,150 

1,125 

- 1.,100 (D 

E 

(I) 

> 

0 

.c 1,075 "' ai 

(I) 

--

.2 1.,050 -

"' > 

(I) 

iii 

1,025 

1,000 

Surglus Condition, 

1, .... -1 n ana u,ove 

Normal Con bition 

1,075 tc 1,1• 5 ft 

- .... l~I 

Lake Mead End of Month Elevations 

Projections from the April and June 2018 24-Month Study Inflow Scenarios 

I 

Hi: ton1cal Funm 

,.,I J:--+. 

---- ... ~ I I ..... ---:.:.--i-~~;;"1'-=}i~, , , "' ~ I -4f----··--

Level 1 Shortage Condit on ----~rt:-=

.:ri= 

1,060 I 1.076ft I 

.... 

... 

-, 

~ 

-it•~<-Ion 

1,025 i 1, 50 ft 

Level ! Sh! rtage Condi 

1,025 ~ •r below 

ion 

... ... .... ... ... ... ... ... .... ... ... 00 CD CD 00 CD CD CD CD CD co CD CD 0, en en Cl en en en ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... "' ...• • • ' • '5 . • . > • • • • • . • '5 . • . > • • • • • ' • '5 . ,c ~ ... >- C a, Q, - " C ,c ~ ... ~ C a, Q, - " ~ ,c ~ ... ~ C a, 

Cl) 

~ "' :::J :::J ., " 0 ., "' Cl) a, :::J :::J Cl) " 0 ., ., a, :::J :::J 

i.. :ii: :: -, -, < II) 0 z Q -, i.. :ii: <( :: -, -, < II) 0 z Q -, i.. :ii: <( :: -, -, < 

-----Aprtl 2018 Probable Maximum lnftowwtth Lake Powell Release ot 9.00 mar In WY 2018 and WY 2019 

- - June 2018 Most Probable Inflow wtth Lake Powell Release of 9.00 mar In WY 2018 and WY 2019 

---- Aprtl 2018 Probable Minimum Inflow with Lake Powell Rel ease of 9.00 mar In WY 2018 and 8.81 mar In WY 2019 

"' "' cn en ... ... ... ... • . > • Q, - " Cl) " 0 ., 1/) 0 z Q 
Unit 

Number

Oct 

2017

Nov 

2017

Dec 

2017

Jan 

2018

Feb 

2018

Mar 

2018

Apr 

2018

May 

2018

Jun 

2018

Jul 

2018

Aug 

2018

Sep 

2018

1

2

3

4

5

6

7

8

Units 

Available 6 6/4 4/6 6 4/6 5/6 5/6 5 6/7 7 7 5

Capacity 

(cfs) 21,000 13,200 13,200 20,600 13,000 12,000 15,700 15,600 12,200 23,900 23,900 12,600

Capacity 

(kaf/month) 1,290 970 1,170 1,260 780 1,060 1,130 980 1,210 1,470 1,470 1,190

Max (kaf) 1 667 630 740 860 730 800 705 705 760 860 900 670

Most (kaf) 2 640 630 740 860 730 800 705 705 760 860 900 670

Min (kaf) 1 630 630 740 860 750 780 683 700 760 860 900 670

11

Glen Canyon Power Plant Planned Unit Outage Schedule for Water Year 2018

1 Projected release, based on Apr 2018 Min and Max Probable 

Inflow Projections and 24-Month Study model runs

2 Projected release, based on June 2018 Most Probable Inflow 

Projections and 24-Month Study model runs

9.0

9.0

9.0

(updated 6-11-2018)

CII D 

" 

[J CJ 

[J .. CJ 

• .. • 

I I I 

I I I 

RECLAMATION 
Experimental Macroinvertebrate

Production Flow (Bug Flow)

• Approved by Assistant Sec. Water & Science on April 13.

– Experiment is for May through August

– Steady weekend flows.

– Normal hydropower production flows during week days.

– No monthly or weekly volumes flow changes.

– Week day fluctuating flows follow LTEMP guide lines.

12
13

"' "' "' "' "' "' ... a, co 0 "' .c,. a, a, 0 "' .c,. a, a, 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 

en 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 

;;r 5/01 - Tu e 

(D 

Cl. 

C: 5,U2 - Wed 

ar G) Cl. 

I 

5:U3 - Thu 

-

Cl) 0 

C: 5.104 - Fri ::I 

'< 51

U5 - Sat 0 ;:o 

!!!. Cl) 

(D 5/06 - Sun ::I 

., 

Ill '< 

(D 5/07 - Mon 0 Ill ::I 5/08 - Tu e 

5/09 -Wed 0 Cl) 

[IJ 5/10 - Thu 3 C: 

'° "Tl 

5/11 - Fri I 

0 0 :E 5112 - Sat C 

m -, 

X 511 3 - Sun '< "tJ (D 

:::,. 5/14 - Mon OJ 3 

(D C 

3. 0 5/15 - Tu e <C ::0 Ill 5/16 -Wed -n IS- r+ (D 0 ., I 5i17 - Thu !fl :r 

Ill 0 C 

5/18-Fri 'iJ --, 

I 5i19 - Sal Cl) 

)> 5/20 - Sun 

--

Cl) 

g_ -, 

C: 5/21 - Mon ::I 

I!!. I 5122 - Tu e ?:: 

0 0) C: 5/23 - Wed '< 

::0 5124 - Thu I'\) 

(D 0 ar 5.1'25 - Fri ., -->. 

Ill co (D Ill 5/26 - Sat 
14

"' "' "' "' "' "' ... a, co 0 "' .c,. a, a, 0 "' .c,. a, a, 0 0 0 0 0 0 0 0 0 0 0 0 0 0 

0 

0 0 

0 

0 

0 0 

0 0 

0 

0 

0 0 

0 0 

0 

0 

0 0 

0 0 

0 

0 

0 0 

0 0 

0 0 

6/01 • Fri 

6/02 • Sat 

7J 

6/03 - Sun 0 

.-+ 

6,'04 • M

on (1) 

:J 

6i05 • Tue .-+ 

Q) 

6!ll6 - Wed 

G') 

6i07 • Thu (1) 

6.108 · Fri ::I 

6/09 • Sat (") Q) 

6/10 • Sun :J '< 

6/11 - M

on 0 :J 

6/12 • Tu e 0 

6/1 3 - W

ed Q) 

6i14 • Thu 3 

0 I 

Ill 6/15 - Fri 0 

..+ C <D 6116 • Sal I ::::!.. 

:r 6117. 

Sun '< 0 

C 

--, a:J 6/1 8 • Mon C 

6/19 • Tu e (0 

,, 

6/20 • W

ed 

-

0 

6/21 • Thu 

6/22 • Fri 7J Q) 

6/23 • Sat --(1) 

6/24 - Sun .... ::I 

6.1'25 - Mon L 
15

"' "' "' "' "' "' ... a, co 0 "' .c,. a, a, 0 "' .c,. a, a, 0 0 0 0 0 0 0 0 0 0 0 0 0 0 

0 

0 0 

0 

0 

0 0 

0 0 

0 

0 

0 0 

0 0 

0 

0 

0 0 

0 0 

0 

0 

0 0 

0 0 

0 0 

7101 • Sun 

7!02 - Mon 

7103 - Tu e 7J 0 

7,U4 • Wed 

-

(1) 

::I 71U5 • Thu 

-

7.106 - Fri 

0) 

-

7,U7 - Sat G) 

(1) 7/08 • Sun ::I 

7l09 • Mon () 

0) 

7110 - Tu e ::I 

7/11 - Wed '< 0 

7112 - Thu ::I 

7/1 3 • Fri 0 0) 

7114 - Sat 3 

0 7115 . Sun I 

Ill 7/1 6 • Mon 0 ..+ C <D 

I ..... 

:r 7i17 - Tu e '< 0 

C 

--, 7/18 -Wed OJ C 7i19 • Thu (0 

7.120 • Fri "Tl 

7/21 - Sal 0 

7122. 

Sun :E 

7J 

7.123 - Mon 0) 

7124 - Tu e 

--

(1) 

7!'25 • Wed 

..... 

::I 

7126 

Thu c_ 
16

"' "' "' "' "' "' ... a, co 0 "' .c,. a, a, 0 "' .c,. a, a, 0 0 0 0 0 0 0 0 0 0 0 0 0 0 

0 

0 0 

0 

0 

0 0 

0 0 

0 

0 

0 0 

0 0 

0 

0 

0 0 

0 0 

0 

0 

0 0 

0 0 

0 0 

8/01 - Wed 

81U2 - Thu 

8/03 - Fri 7J 0 

..... 

B,U4 - Sal CD 

::J 

8l05 - Sun ..... 

8.106 - Mon 

0) 

-

8/07 - Tue G) 

CD 8/08 -Wed ::J 

8109 - Thu () 

8.110- Fri 0) ::J 

8/11 - Sal '< 0 

8112 - Sun ::J 

8/1 3 -

M

on 0 0) 

8114 - Tu e 3 

O 8/15 - \",led I 

Ill 

8116 - Thu 0 ,-+ C: <D 

I -, 

:r 811 7 - Fri '< 0 

C 

--, 

8/18 - Sal OJ 

C: 8,'19 - Sun (0 

8.120 - Mon "Tl 

8/21 - Tue 0 

t.122 -Wed :E 

7J 

6/23 - Thu 0) 

8.124 - Fri 

..... ..... 

CD 

-, 

8/25 - Sal ::J 

8;26 - Sun • 
Water Year 2019

Projected Operations

17
Lake Powell 2019 Operating Tier Scenarios 

Based on June and April 2018 modeling 

Inflow 

Scenario

Operating Tier

Release Volume

Minimum

Probable

Upper Elevation Balancing

8.8 maf

Most

Probable

Upper Elevation Balancing

9.0 maf

Maximum 

Probable

Upper Elevation Balancing

9.0 maf

18
19

LTEMP Monthly Release Volumes 

1 /i!lfl 

,,,on 

n uu 

-

~ " 

~ u 1000 

"' 0 

-0 "'

"' C: Rm 

"' ;;, 

0 

,::_ 

,_ 

OJ 

V> 

"' bOO 

,!? 

"' "' 

4L\) 

() 

OCT NOV DEC JAN f EB MAR \1AY JUN JU_ AUG SEP 

Monthly J)P.r WVT~rgP.t, Mill ioM ot ~r.rP.-tP.P.t 

• I • l.48 • 8.B • Y • Y., • 10., • 11 • n • B • 14 
LTEMP Monthly Release Volumes

Month 7.00 7.48 8.23 9.00 9.50 10.50 11.00 12.00 13.00 14.00

OCT 480 480 640 640 640 640 640 640 640 640

NOV 500 500 640 640 640 640 640 640 640 640

DEC 600 600 720 720 720 720 720 720 720 720

JAN 660 720 760 860 920 1040 1100 1230 1350 1470

FEB 590 640 680 750 810 920 970 1080 1190 1300

MAR 620 675 710 800 860 970 1030 1150 1260 1370

APR 550 600 640 710 760 870 920 1020 1120 1220

MAY 550 600 630 710 760 860 910 1020 1120 1220

JUN 580 630 660 750 800 910 960 1060 1170 1280

JUL 650 710 750 850 900 1020 1080 1200 1320 1440

AUG 700 760 800 900 970 1090 1160 1280 1410 1540

SEP 520 565 600 670 720 820 870 960 1060 1160
1,600 

1,400 

1,200 

<P 

ro 

.:.:: 

~ 1,000 

<I) 

E 

::, 

g 800 

<I) 

rJ) 

ro 

<I) 600 <I) 

0:: 

400 

200 

Projected Lake Powell Monthly Release Volume Distribution 

Release Scenarios for Water Year 2019 

Based on June and April 2018 modeling 

WY 2019 Release Scenarios 

Apr Probable Min 8.80 maf 

Jun Most Probable: 9.0 maf 

Apr Probable Ma)(; 9.0 maf 

co 

.--

8 

co 

.--

::?-

0 

z 

0) 

.--

c: 

ro 

7 

0) 

r-

..c 

Cl) 

IL 

O> 

.-- C: 

::, 

7 

~ Probable Min • June Most Probable D Probable Max 

!JOU 
Unit 

Number

Oct 

2018

Nov 

2018

Dec 

2018

Jan 

2019

Feb 

2019

Mar 

2019

Apr 

2019

May 

2019

Jun 

2019

Jul 

2019

Aug 

2019

Sep 

2019

1

2

3

4

5

6

7

8

Units 

Available 6 8 6 6 6 4/6 6 7 8 8 8 6

Capacity 

(cfs) 19,100 26,100 19,100 19,100 19,100 12,200 19,000 22,700 26,100 26.100 26,100 19,100

Capacity 

(kaf/month) 1,240 1,550 1,200 1,170 1,060 1,140 1,190 1,480 1,550 1,600 1,600 1,180

Max (kaf) 1 640 640 720 860 750 800 710 710 750 850 900 670

Most (kaf) 2 640 640 720 860 750 800 710 710 750 850 900 670

Min (kaf) 1 640 640 720 820 730 760 690 680 710 810 860 644

22

Glen Canyon Power Plant Planned Unit Outage Schedule for Water Year 2019

1 Projected release, based on Apr 2018 Min and Max Probable 

Inflow Projections and 24-Month Study model runs

2 Projected release, based on June 2018 Most Probable Inflow 

Projections and 24-Month Study model runs

9.0

8.7

9.0

(updated 6-11-2018)

Possible HFE

I 117 ., ., u lJ u 

1= 1 

1= 1 

•Iii 

I 

RECLAMATION 
Questions?

Paul Davidson

801-524-3642

PDavidson@usbr.gov

Hydraulic Engineer, Glen Canyon

Reclamation, Upper Colorado Region

Resource Management Division

Water Resources Group