USGS LOGO
2002 California Hydrologic Data Report

11399000 LAKE ALMANOR AT PRATTVILLE, CA.

 

LOCATION - Lat 40°12'46", long 121°09'43", in SW 1/4 NE 1/4 sec.11, T.27 N., R.7 E., Plumas County, Hydrologic Unit 18020121, Lassen National Forest, at intake tower to Butt Valley Tunnel at Prattville, 4.7 mi northwest of Lake Almanor Dam, and 5.6 mi northwest of Canyondam.
 

DRAINAGE AREA - 491 mi2.

 

PERIOD OF RECORD - July 1913 to current year. Monthly contents only for some periods, published in WSP 1315-A. Published as "near Prattville" 1937.60. Prior to October 1964, records published as usable contents.

 

REVISED RECORDS - WSP 1931: Drainage area.

 

GAGE - Nonrecording gage read once daily. Datum of gage is 10.23 ft below sea level (levels by Pacific Gas & Electric Co. Prior to June 1, 1965, nonrecording gage at site 4.7 mi southeast at same datum.

 

REMARKS - Lake is formed by earthfill dam; storage began in July 1913; dam raised to gage height 4,455 ft in 1917 and 4,515 ft in 1927. Usable capacity, 1,175,000 acre-ft, between gage heights 4,422 ft, invert of outlet, and 4,495.5 ft, maximum storage limit. Dead storage, 8,948 acre-ft. Water is diverted by tunnel and penstock to Butt Valley Powerplant (station 11400600) and then is used for power development in the North Fork Feather River. Figures given, including extremes, represent total contents at 2400 hours. See schematic diagram of North Fork Feather River Basin.

 

COOPERATION - Records were collected by Pacific Gas & Electric Co., under general supervision of the U.S. Geological Survey, in connection with a Federal Energy Regulatory Commission project. Contents not rounded to U.S. Geological Survey standards.

 

EXTREMES FOR PERIOD OF RECORD - Maximum contents, 1,142,960 acre-ft, June 8, 1982, gage height, 4,494.00 ft; minimum, 5,230 acre-ft, Feb. 5, 1918, gage height, 4,416.1 ft.

 

EXTREMES FOR CURRENT YEAR - Maximum contents, 909,943 acre-ft, June 30, gage height, 4,485.06 ft; minimum, 604,959 acre-ft, Nov 9, 10, gage height, 4,471.89 ft.

 

Capacity table (gage height, in feet, and contents, in acre-feet)

(Based on surveys by Pacific Gas & Electric Co. in 1924 and 1926)

4,422

8,948

4,432

34,173

4,445

156,414

4,470

565,519

4,424

10,067

4,434

49,510

4,450

220,848

4,480

787,304

4,426

11,260

4,437

74,189

4,455

94,531

4,490

1,036,269

4,428

13,480

4,440

101,869

4,460

376,686

4,495.5

1,183,835

4,430

21,200

 

                

RESERVOIR STORAGE (ACRE-FEET), WATER YEAR OCTOBER 2001 TO SEPTEMBER 2002

DAILY OBSERVATION AT 2400 HOURS

Day

Oct

Nov

Dec

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

1

659,522

610,473

622,452

647,693

693,454

729,792

773,635

839,330

893,318

908,947

878,539

832,584

2

657,541

609,411

626,333

651,622

694,349

730,715

775,284

840,779

895,051

908,947

877,308

830,182

3

655,126

609,198

626,765

653,592

695,244

732,100

777,172

842,472

895,794

908,449

876,816

827,305

4

652,716

609,198

627,629

655,565

696,141

733,255

780,218

843,683

895,051

908,698

875,832

823,939

5

650,311

608,561

658,201

658,201

697,038

735,338

782,324

845,864

895,299

909,196

873,867

821,527

6

647,693

607,076

629,794

661,064

697,711

736,716

784,434

847,806

894,804

908,449

872,394

819,360

7

645,952

606,017

630,227

663,493

700,183

739,466

786,782

849,508

895,051

907,454

870,433

817,196

8

643,535

605,171

630,444

665,484

700,859

741,072

788,663

851,445

895,299

905,963

869,209

816,716

9

642,218

604,959

630,661

667,478

701,759

742,451

791,490

853,139

895,794

904,969

867,741

814,556

10

640,903

604,959

630,661

669,699

702,435

744,752

794,322

854,835

896,290

902,984

866,518

811,921

 

11

639,372

605,806

630,227

670,588

703,112

746,596

796,688

856,776

897,282

901,002

865,297

810,964

12

637,842

608,349

630,661

672,146

704,014

748,443

799,294

858,233

897,530

899,019

865,541

808,574

13

636,751

609,198

632,397

673,483

704,917

750,292

801,905

859,692

898,522

898,522

865,297

806,666

14

635,007

610,048

634,137

674,599

705,821

751,218

805,236

861,639

899,019

897,778

863,589

804,283

15

633,267

610,899

633,049

675,939

706,952

752,144

807,858

863,101

900,011

896,786

862,126

801,905

16

631,529

611,750

632,397

676,833

707,857

753,535

810,486

865,053

900,754

895,547

859,692

799,294

17

629,794

612,602

632,832

677,728

709,443

754,463

812,400

867,007

901,497

894,061

858,233

797,161

18

628,062

613,455

633,484

678,624

710,351

755,391

813,837

868,719

901,993

893,071

856,776

794,795

19

626,333

614,308

634,137

679,520

713,304

756,321

815,756

871,413

902,984

891,341

855,078

792,669

20

625,038

614,522

636,751

680,866

715,353

757,483

817,677

873,867

903,480

890,600

853,623

790,547

                       

21

623,313

615,590

637,187

682,214

717,177

758,647

819,120

875,341

904,225

889,612

851,929

788,192

22

621,592

615,590

638,061

683,113

717,405

760,278

820,805

876,324

905,218

888,378

850,236

785,842

23

619,659

615,590

638,497

684,013

721,062

761,911

822,492

878,293

905,714

887,146

848,535

783,730

24

619,016

617,944

638,716

684,914

722,895

763,312

824,422

879,771

906,460

886,161

846,835

781,621

25

619,230

617,730

639,372

685,815

724,730

764,481

826,587

880,752

907,205

884,930

845,137

779,282

26

617,515

617,515

638,934

688,297

725,649

765,651

829,223

882,225

907,952

883,208

843,199

777,172

27

615,804

616,873

639,153

689,202

727,259

767,056

832,103

883,700

908,449

882,962

841,989

774,813

28

614,522

618,372

640,903

690,326

727,949

767,994

834,027

885,914

908,947

882,717

841,021

772,693

29

614,308

619,445

641,999

691,219

---

769,402

835,953

887,885

909,445

881,489

838,847

770,341

30

613,455

619,874

644,193

691,889

---

770,811

837,882

889,859

909,943

880,998

836,435

767,994

31

611,963

---

645,732

692,783

---

772,222

---

891,835

---

879,771

834,749

---

                       

Max

659522

619854

645732

692783

727949

772222

837882

891835

909943

909196

878539

832584

Min

611963

604959

622452

647963

693454

729792

773635

839330

893318

879771

834749

767994

a

4472.22

4472.59

4473.78

4475.90

4477.45

4479.36

4482.12

4484.33

4485.06

4483.84

4481.99

4479.19

b

-50655

+7611

+25858

+47051

+35166

+44273

+65660

+53953

+18108

-30172

-45022

-66755

 

CAL YR 2001 MAX 796688 MIN 604959 b -78769

WTR YR 2002 MAX 909943 MIN 604959 b +105376

 

a Gage height, in feet, at end of month

b Change in contents, in acre-feet