LADM-NO 1130-2-24 Sepulveda Dam FCB OM Manual 12-1970.pdf

L A D M NO. 1130-2-24

OPERATION AND MAINTENANCE

MANUAL

FOR

SEPULVEDA DAM

LOS ANGELES RIVER IMPROVEMENT

LOS ANGELES COUNTY DRAINAGE AREA

CALIFORNIA

ttM~_

~ DEPARTMENT OF THE ARMY, LOS ANGELES DISTRICT

CORPS OF ENGINEERS

DECEMBER 1970 -----

LADM NO. 1130-2-24 Department of the Army, Los Angeles District, Corps of Engineers December 1970

F 0 R E W 0 R D

1. This manual prescribes standard procedures for the operation and maintenance of the federally constructed Sepulveda Dam, Los Angeles County Drainage Area, California.

2. The Operations Branch of the Construction Division is responsible for the preparation of this manual and for keeping the manual up to date.

Suggestions for revisions should be forwarded through channels to that branch.

3. All exhibits not attached to this manual may be found in the Operations Branch, Construction Division.

4. This manual rescinds LADM No. 1130-2-24, Sepulveda Dam, dated April 1963.

NO.

TABLE OF CONTENTS

TITLE

PART I - GENERAL

Introduction

PAGE

1. Authority

2. Purpose

3. Parts of manu a 1.......................................... l

4. Scope of manua 1

Project Description

5. Authorization

6. Project location .......................... ;

7. Description of project

8. Recreational development

9. Pertinent data

10. Construction history

PART II - OPERATION AND MAINTENANCE

General

l. Information

2. Reference drawings and manuals

3. Functions of the Construction Division .............. ·

4. Functions of the E ngi neeri ng Division

5. Functions of the Real Estate Division

6. Functions of the U. s. Geological Survey

7. Functions of the Safety Office c

8. Uuties of the Dam Operator

Reservoir Area and Embankment

9. Description

10. Method of reservoir operation

11. Dam Operator 1 S house

12. Inspections and maintenance

Outlet Works

13. Description

14. Los Angeles River improvement

15. Approach channel

16. Control house

17. Trash racks

18. Outlet channel

1 Y. Foundation drainage

20. Fences

21. Inspection and maintenance

Spillway

22. Description

23. Walls

24. Slabs

25. Spillway bridge

26. Location of controls and access tunnel

27. Inspections and maintenance

Slide Gates and Crest Gates

28. S 1 ide gates

29. Slide gate control ................................... ·

30. Automatic gate hangers

31. High pressure oil lines

32. Gate air vents

33. Crest gates

34. Crest gate centro 1

35. Crest gate operation

36. Inspections, tests, and maintenance

Electrical Facilities

37. Electrical supply

38. Standby genera tor

39. Diesel oil storage

40. L i gh ti ng

41 . Switchboard

42. Traveling crane

43. Inspections, tests, and maintenance

44. Five-year inspection and maintenance

Hydrographic Installations

45. Staff gages

46. Reservoir water stage recorder

47. Crest gate recorders

48. Crest gate indicators

49. Slide gate position recorders

50. Slide gate position indicators

51. Standard rain gage

52. Automatic rain gages

53. Outflow gaging station

54. Inspection, servicing, maintenance, and reporting

Communication Facilities

55. Radio station

56. Telephones

57. Maintenance of radio facilities

58. Telephone maintenance

59. Maintenance of intercommunication telephone service

Water Supply and Sewage

60. Water supply system

61 . Sewage sys tern

62. Inspections and maintenance

Fire-Fighting Equipment and Fire Prevention and Accident Prevention

63. Control house

64. Dam Operator•s house

65. Garage

66. Inspections, tests, and maintenance

67. Accident prevention

Foundation and Materials Instrumentation

68. Instrumentation at Sepulveda Dam

69. Responsibility for instrumentation measurement

NO.

A

B ( c

D

E

F

G

H

I

J

K

L

EXHIBIT

TITLE

Project Location

Drawings Half-size (Unattached)

Master Recreation Plan

Reference Manufacturers Manuals (Unattached)

1 Sheet

1 Sheet

Maintenance Chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sheet

Inspection Check List .. .. . .. .. .. .. .. .. .. .. . .. .. .. .. .. .. Sheet

Test Reports............................................ Sheet

Instructions for Operation of Gates and Appurtenances... 3 Sheets

Operation of Crest Gates................................ 4 Sheets

Starting the 0320 Diesel Standby Unit . . . . . . . . . . . . . . . . . . 2 Sheets

Operation of Switchboard............................... 1 Sheet

Foundation and Materials Instrumentatio~ .. .. ... ........ 2 Sheets

OPERATION AND MAINTENANCE MANUAL

FQR

SEPULVEDA DAM

LOS ANGELES RIVER IMPROVEMENT

LOS ANGELES COUNTY DRAINAGE AREA, CALIFORNIA

PART I - GENERAL

Introduction

1. Authority.-- This manual was prepared pursuant to ER 1130-2-304, dated 25 March 1966, which directs the preparation and prescribes the coverage of operation and maintenance manuals for completed civil works projects operate~ by the Corps of Engineers.

2. Purpose.-- The purpose of this manual is to provide guidance and instructions to the Dam Operator and District operating personnel for proper operation and maintenance of Sepulveda Dam. These instructions provide for the continuous maintenance of structures and equipment and their operation in such a manner and at such times as will produce optimum benefits.

3. Parts of manual.-- This manual has been prepared in two parts:

(1) general description of the completed project~ and (2) Operation and Maintenance instructions, for the major and critical project equipment and facilities installed at Sepulveda Dam.

4. Scope of manual.-- The scope of this manual is limited to essential operation and maintenance instructions and covers the operating parts, their purpose, and technique of operation in sufficient detail to insure proper operation.

Project Descrirtion

5. Authorization.-- Sepulveda Flood Control Basin was constructed under author1zat1on of the Flood Control Act of 22 June 1936, as amended by the Flood Control Act of 28 June 1938 and was incorporated into the comprehensive plan of the improvement for the control of floods in the Los Angeles County Drainage Area by the Flood Control Act of 18 August 1941.

6. Project location.-- The Sepulveda Dam is located in the San Fernando Valley on the upper Los Angeles River at river mile 43, about 2 miles southwesterly of the community of Van f~uys and west of Sepulveda Boulevard, within ·the city limits of Los Angeles, California.

The location of the project is shown on Exhibit A. The drainage system above the damsite has an area of 152 square miles, comprising about 82 square miles of relatively steep mountainous terrain and about 70 square miles of comparatively flat valley floor. The boundary (.

of the catchment area on the south is formed by the crest of the Santa Monica Mountains, having an average elevation of about 1,700 feet;

on the west by the crest of the Simi Hills, having an average elevation of about 1 ,800 feet; on the north by the crest of the Santa Susana Mountains, having an average elevation of about 2,800 feet; and on the east by a line extending approximately north and south across the valley and along Sepulveda Boulevard. The highest point in the drainage area is San Fernando Peak, having an elevation of 3,741 feet. (See drawing 133/ll of Exhibit B.)

7. Description of project.-- The principle construction features of the Sepulveda Flood Control Basin are:

a. Sepulveda Basin, which is used exclusively for flood control, has a storage capacity of 17,300 acre-feet at crest of spillway gates raised (elevation 710 feet), and will reduce the standard project flood from a peak inflow of 42,500 cubic feet per second (c.f.s.) to a regulated outflow of 16,500 c.f.s. with the water surface at crest of spillway gates.

b. The Dam, consisting of an unzoned impervious rolled-earth embankment and a reinforced-concrete spillway and outlet structure, is 15,444 feet long. The embankment has a maximum height of 57 feet, and a volume of 2,541,000 cubic yards. (See drawings 133/22 and 133/23 of Exhibit B.)

c. The outlet works are at the right of the spillway section in the central part of the dam. There are 4 gated outlets, 6 feet wide by 9 feet high, and 4 ungated outlets, 6 feet wide by 6.5 feet high, with inverts and gate sills all at elevation 668 feet. These outlets discharge through separate conduits, 47 feet long, into a rectangular outlet channel, tapering in width from 83 to 50 feet, bordering the right side of the spillway. Beyond the end of the spillway the channel ( continues 50 feet wide for about 1,840 feet downstream. (See drawing 133/25 of Exhibit B.)

d. The spillway is a concrete ogee section, crest elevation 700 feet with seven 57 feet by 10 feet automatic drum gates. Spillway flow is discharged upon a rectangular concrete slab, 469 feet wide and 488 feet long terminated by a sheet piling cutoff and a derrick stone apron 200 feet long. (See drawing 133/27 of Exhibit B.)

e. Access roads.-- Access to the Dam and flood control basin can be obtained from Burbank Boulevard, a city street running east and west through the flood control basin. Another access is from the Haskell Avenue west bound on-ramp to the Ventura Freeway.

8. Recreational development.-- Under the terms of ~ 50-year re creational license granted 11 June 1951, approximately 2,000 acres are being developed and maintained for public recreational activities by the City of Los Angeles, Department of Parks and Recreation.

(See Exhibit C.)

9. Pertinent data.--

Drainage area .................................... sq. mi... 152

Reservoir:

Elevation

Flood-control pool (spillway gates raised).ft., m.s.l .. .

Spillway design surchar~e level ............ ft., m.s.l .. .

Area (survey of June 1961) S pi 11 way crest ..................................... ac .. .

S p i 1 1 way g a te s r a i sed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . a c . . .

Spillway design surcharge level .................... ac .. .

Top of dam ......................................... ac .. .

Capacity, gross (survey of June 1961)

717.6

1 ,340 1 ,800 2,510

Spillway crest ................................. ac.-ft... 6,830 Spillway gates raised ................. ; ........ ac.-ft. .. 17,300 Spillway design surcharge level ................ ac.-ft. .. 29,120 Top of dam ..................................... ac.-ft... 44,720 Allowance for sediment ......................... ac.-ft... 0

Dam- type .................................................. Earth fi 11 Top elevation .............................. ft., m.s.l... 725 Height above original streambed .................... ft... 57 Top length (including spillway) .................... ft... 15,444 Top width .......................................... ft... 30 Freeboard .......................................... ft... 7.4

Spillway-type .............. concrete ogee with 10ft. crest gates Overall length (7 gates at 57 feet) ................ ft... 399 Ogee crest elevation ....................... ft., m.s.l... 700 Gate crest elevation (gate in raised position) ............... ft.,m. s.l .. .

Maximum surcharge on ogee crest .................... ft .. .

Discharge at design surcharge ................... c.f.s .. .

Outlets:

Ungated:

17.6

108,900 i~umber Size .............. ; ..................................... 6 1 WX6. 51 H Entrance invert elevation .................. ft., m.s.l... 668 Gated:

Number Size .................................................... 6 1 WX9 1 H Entrance invert elevation Gate type ........................................... Vertical lift

Conduits Number Length ................................. · · · · · · · . · · · · · · · · ·

Maximum capacity (spillway gates in raised position) ......................... c.f.s .. .

Regulated capacity (spillway gates in r,aised position) ......................... c. f. s .. .

16,500

16,500

Reservoir design flood: (original design) Duration ..................................... days .. .

Total volume ............................... ac.-ft .. .

Inflow peak ................................. c.f.s .. .

Outflow peak ................................ c.f.s .. .

Reduction in peak ........................... c.f.s .. .

Spillway design flood:

Duration ..................................... days .. .

Inflow volume for 24-hour period of greatest runoff ............................... ac. -ft .. .

Inflow peak ................................. c.f.s .. .

Outflow peak ................................ c.f.s .. .

Reduction in peak ........................... c.f.s .. .

Standard project flood: (current flood-control operation) Duration ............................... · ...... days .. .

Total volume (including base flow) ......... ac.-ft .. .

Inflow peak ................................. c. f. s .. .

Outflow peak ................................ c. f. s .. .

Reduction in peak ........................... c.f.s .. .

Maximum probable flood:

Duration ..................................... days .. .

Inflow volume .............................. ac.-ft .. .

Inflow peak ................................. c. f. s .. .

Outflow peak (current flood-control operation plan) ........................ c.f.s .. .

Reduction in peak ........................... c.f.s .. .

52,880 69,000

7 '100 61 ,900

70,380 177,000 108,900 68 '100

63,900 42,500 16,500 26,000

121 ,940 220,000

158,000 62,000

10. Construction history.-- Construction was accomplished under the foll owi'ng major contracts:

a. Dam and appurtenant work.--

Contractor:

Contract No.:

Work Started:

Work Completed:

b. 6 Feet wide by 9 Feet high--Slide gates.--

Contractor:

Contract No.:

Work Started:

Work Completed:

c. 57 Feet wide by 10 Feet high- Cre~t gates.~-

Contractor:

Contract No.:

Work Started:

Work Completed:

d. Training Walls.--

Contractor:

Contract No.:

Work Started:

Work Completed:

John-Bressi-Bevanda Constructors, Inc.

J. A. Dowling and D. G. Gordon

W-509-ENG-966

31 December 1939 30 December 1941

Commercial Iron Works

W-509-ENG-1035

November 1940 July 1941

Consolidated Steel Corporation

W-509-ENG-995

1 December 1940 July 1941

Fricke Barrington 66-174 6 July 1966 28 July 1966

PART II - OPERATION AND MAINTENANCE

General

l. Information.-- Special terms used in this manual are:

a. 11 Fl ood Season 11

- refers to the peri ad from 15 October to

15 April when most past floods have occurred.

b. 11 Emergency Flood Conditions 11

- refers to periods during which the reservoir water surface rises above the crest of the spillway at elevation 496.

c. All elevations refer to feet above 11 mean sea level 11 datum.

2. Reference drawings and manuals.-- Drawing file numbers in this manual refer to ''as-constructed 11 drawings; half-size reductions are included as Exhibit Band are separately bound. Drawings, manuals, and instructions for manufacturers' equipment are listed in Exhibit D and are on file in the District Office, Maintenance Yard, and at the project.

3. Functions of the Construction Division.-- Operation and maintenance and all inspections are under the superv1s1on of the Construction Division, which assigns this responsibility to the Operations Branch.

The general duties include the following:

a. The Operations Branch shall train key personnel in order that regular inspection, operation, and maintenance work will be performed efficiently, an~ to insure that unexpected problems related to flood control may be handled in an expeditious and orderly manner. The men shall become familiar with the provisions of this manual, the supplements A, B_, and C of LAD OM 500-1-1, and the 11 as-constructed 11 drawings.

b. The Operations Branch shall report violations of outgrant terms to Real Estate Division for official action when they cannot be handled informally.

c. The Operations Branch prepares and executes all flood fighting plans and through the Regulation and Meterorology Section directs the Dam Operator or his alternate in the operation of the gates. The Dam Operator or his alternate shall keep records of reservoir stages, inflow to the reservoir, releases through the outlet structures, and spillway flow.

d. The Regulation and Meteorology Section, Operations Branch is responsible for the inspection, servicing, and maintenance of all hydrographic installations and radio installations. (Their routine inspections are made by the Dam Operator.)

e. Periodic inspections shall be made by the Engineering Evaluation and Inspection Section, Operations Branch, in order to determine maintenance measures necessary to insure serviceability of the works in time of flood. Such inspections shall be made immediately following ( each major highwater period, at intervals not to exceed six months, and at such other times as may be necessary. Immediate steps shall be taken to correct dangerous conditions disclosed by such inspections, and regular maintenance repair measures shall be accomplished during the appropriate season as scheduled by the Chief, Operations Branch.

All repairs shall be made in accordance with standard engineering practice to line, grade, and quality and in accordance with relevant details shown on 11 as-constructed" drawings, Exhibit B.

f. The Engineering Evaluation and Inspection Section, Operations Branch, reviews plans and furnishes comments to Real Estate Division on requests from public or private interests for collateral use of land and water areas and performs inspections during construction to assure compliance with approved plans.

g. The Maintenance Section, Operations Branch, shall establish a file of all reports and records concerning the operation and maintenance of the project works. (See Exhibit E.)

4. Functions of the Engineering Division.--

a. Conducts or participates in periodical condition surveys of the project with representatives from Construction Division, South Pacific Division, and Office of the Chief of Engineers. These surveys serve a two-fold purpose: (1) ascertain the condition of the various parts of the project; and (2) see that all repairs and improvements have been carried out that were previously recommended.

b. Performs engineering review of plans of proposed development on project land or water areas, as requested by the Construction Divisi@n.

c. Furnishes engineering comments on request of public or private interests for collateral use of land and water areas as requested by Construction Division.

d. Reports to Construction Division all trespass or violation of outgrants discovered by Engineering Division personnel.

5. Functions of the Real Estate Division.--

a. Processes all permits, licenses, easements, or leases through appropriate channels and administers completed instruments.

b. Insures compliance through periodic inspections and acts upon all violations of outgrants.

c. Furnishes the Construction Division copies of all permits, licenses, easements, or leases.

6. Functions of the U. S. Ge·ological Survey.-- By agreement with the Corps of Engineers, the U. · S. Geo 1 ogi ca 1 Survey (USGS) services the outflow gaging station below the dam on the Los Angeles River.

The USGS makes discharge measurements and compiles and publishes the pertinent records in the U. S. Geological Water Supply papers.

7. Functions of the Safety Office.-- All functions involving safety are under the supervision of the Chief, Safety Office. The Safety Office shall perform periodic inspections to insure compliance with appropriate safety codes and standards of all activities in the project a rea.

8. Duties of the Dam Operator.-- The Dam Operator or his alternate is required to perform the following duties:

a. Be present at the dam when rainfall or runoff occurs.

b. See that all equipment at the project, including recording and indicating gages, gate mechanism, power units, radio, etc., is in operating condition.

c. Operate the gates in accordance with instructions from the Operations Branch, Construction Division.

d. Follow the fixed gate operation schedule posted in the control house in the absence of communications with the Operations Branch, Construction Division, or in the absence of a representative from that group.

e. Upon rece1v1ng written instructions from Regulation and Meterorology Section services all gages and recorders, wind the clocks, install new records, paper, etc.

f. Guard the project against vandalism, sabotage, and fires.

g. Guard against unsafe conditions in the project area.

h. Report on trespassing and encroachment on rights-of-way.

i. Maintain records, including water surface elevations, outflow gage heights, precipitation amounts, gate openings, and log all radio and telephone calls on prescribed forms.

j. Keep premises and equipment clean ahd in good repair; painting will be performed by the Dam Operator when necessary. On larger jobs requiring sandblasting and painting, the maintenance crew will assist.

k. Periodic inspections of structures, equipment, and the project area shall be made by the Dam Operator or his alternate to determine maintenance measures that are required. These inspections during the non-flood seasons shall be made at intervals of not more than 90 days;

during the flood seasons at intervals of not more than 30 days; also c-immediately following each flood. More frequent inspections shall be made if required, for the safety and efficient maintenance of some features of the project. During each inspection, items requiring maintenance shall be checked and described on the inspection check list included as Exhibit F. After each inspection, one. inspection check list shall be promptly submitted to Chief, Engineering Evaluation and Inspection Section, Operations Branch, through Chief, Maintenance Section. Maintenance shall be performed by the Dam Operator, if feasible. Note: If maintenance requires additional labor or equipment, the Dam Operator shall notify the Chief, Maintenance Section of the recommended maintenance measures required. Normal maintenance shall be made without delay.

1. The Dam Operator or his alternate shall test-operate the gates and electrical facilities in the control house every 30 days and the standby power unit every 15 days. Test operation reports (Exhibit G) shall be completed in triplicate after each test. One copy shall be promptly submitted to Chief, Maintenance Section, one copy to Chief, Engineering Evaluation and Inspection Section, and one copy kept on file in the control house of the dam.

Reservoir Area and Embankment

9. Description.-- The Sepulveda Flood Control Reservoir, one unit of a comprehensive plan of flood control, was constructed solely for its value in reducing the peak flows in the Los Angeles River from the dam to the mouth of the river, a distance of about 43 miles. No provision for sedimentation or water conservation storage was planned. The embankment cross section has a top width of 30 feet with an upstream slope of 1 vertical on 3 horizontal and a downstream slope of 1 vertical on 4 horizontal. The upstream face is protected by a 12-inch stone paving laid on 8 inches of graded-crushed rock' the downstream face is covered with grass. The downstream slope has a 20-foot wide berm at ( elevation 710 running parallel with the axis of the dam. (See drawing 136/88 of Exhibit B.)

10. Method of reservoir operation.-- The capacity necessary for flood control storage was predicated upon the volume of inflow from the reservoir design flood and the capacity of the outlet works. From consideration of these factors, the following method of operation was adopted:

a. At the beginning of the flood, all gates will be open and low waterflows will pass through the approach channel, within the basin and thence, through the outlets.

b. When the water in the pool reaches elevation 710.4, the gates will be operated to maintain a constant outflow of 16,500 cubic feet per second, including the discharge through the ungated openings.

c. After the peak flow into the reservoir, a maximum outflow of 16,500 cubic feet per second will be maintained until the pool recedes to elevation 710.4, when all the gates will be completely open.

11. Dam Operator's house.-- The Dam Operator's house is located between the San Diego Freeway and the dam, just northeast of the spillway and is connected with the crest of the dam by a short, un paved road. The house consists of five rooms,and patio. Nearby is a two-car garage with storage space and a tool shed.

12. Inspections and maintenance.-- The Dam Operator or his alternate shall perform periodic inspections and maintenance and shall complete inspection check list as shown in Exhibit F. Maintenance work is described in detail in the following paragraphs:

a. Embankments.-- Maintenance methods for repair or recon struction of the embankments shall depend upon the extent of the damaged section. If the embankment damage is small, sand and gravel or other coarse granular material may be placed in 6-inch layers to restore the embankments. If the damage is large, the fill shall be made in the same manner as the original construction; homogenous material from borrow pits approved for the project shall be placed in uniform horizontal layers not more than 6-inches in depth and compacted to a density equal to the original embankment section.

b. Rock paving and riprap.-- Damaged stone paving, spall blankets, and riprap on the upstream side, the toes and rock-paved gutters shall be repaired promptly. An indication of settlement, uplift, or failure of the riprap structures shall be reported to the Chief, Operations Branch, for recommendation on remedial action.

c. Access roads and berms.-- Access roads and embankment berms shall be adequately maintained for vehicular travel so that ordinary maintenance of the project and flood-fighting operations will be facilitated. ·

d. Burrowing animals.-- Burrowing animals in or near the dam shall be exterminated. Their runways and dens shall be opened, backfilled, and thoroughly compacted at the same time they are backfilled. Trapping and poisoning may be used for the extermination of burrowing animals.

Information about the best methods of animal extermination may be obtained from the county agricultural agent.

e. Hazardous obstruction.-- Reservation area used by authorized personnel shall be kept free from obstruction that may cause injury or impede inspections, maintenance, or flood-fighting operations.

Materials and auxillary construction equipment shall be stored in such a way that they are not hazardous to personnel or capable of floating into the gate structure.

f. Dam Operator 1 s house and appurtenances.-- Painting, re decorating, and similar types of work should be done during the dry season.

g. Vehicles.-- Vehicles and equipment, including tools, shall be kept in first-class condition. Government-owned motor vehicles will be inspected and maintained in accordance with the Operations and Maintenance Motor Vehicles Manual, m~ 56-1-1.

h. Landscaping.-- Landscaping maintenance work includes irrigation, pruning, trimming, and other work required to keep trees, shrubs, flowers, and grass in first-class condition. The area around the Dam Operator 1 s house shall be kept free of excessive equipment or rna teri a l.

i. Miscellaneous.-- Minor structures and facilities, not specifically ~escribed in this manual, shall be inspected at the same time that major adjacent structures and facilities are inspected;

maintenance work shall be performed in accordance with that pre scribed for structures of similar material. The Dam Operator shall be familiar with approved safety measures and first-aid treatment, which are under supervision of the Safety Branch of the district.

The Safety Branch shall arrange for essential instruction in safety and first-aid for the Dam Operator and other key personnel.

Outlet Works

13. Description.-- The outlet structure is situated between the west end of the ogee spillway section and the earth embankment. It is a mono lithic tower, roughly 90 feet wide, 65 feet long and 60 feet high. The control house for the gates is situated on top of this tower and is monolithic with it. The whole structure is supported on piles. The ( ungated outlets are in pairs adjacent to the gated outlets grouped _ in the center of the outlet section. The ungated outlets are provided to allow low-water flows to pass through the dam without operation of the gated outlets. (See drawings 138/17 and 138/28 of Exhibit B.)

14. Los Angeles River improvement.-- Improvement of the Los Angeles River Channel through the basin from the outlet structure (station 1003+58.37) to a point upstream of Louise Avenue (Station 1130+20.42) is included as an appurtenance to Sepulveda Dam. Downstream from station 1130+20.42 to station 1115+00 the channel is a trapezoidal section 250 feet wide with 3 on 1 side slopes paved with grouted rock.

At station 1130+20.42 the unpaved invert is protected by a 25-foot long rock fill. Between station 1115+00 and station 1105+00 a transition of similar construction is provided from the full capacity section to the low-water channel. The downstream end of the transition section is protected by a steel sheet pile cutoff and a 25-foot rock fill section. The low-water channel is fully excavated, unlined, and has a base width of 150 feet and 3 on 1 side slopes. It is designed solely as a low-flow channel to prevent too frequent flooding of the reservoir area. At station 1009+34.87 the unpaved channel terminates at a steel sheet pile cutoff and rock fill protecting a grouted rock paved transition section extending to the outlet structure at station 1003+58.37. (See drawings 133/3 and 139/86 of Exhibit B.)

15. Approach channel.-- The approach channel is a continuation of the ·Los Angeles River Channel and starts 1,000 feet upstream from the axis of the dam on the extension of the centerline of the outlet works.

It is lined with grouted rock paving and has side slopes of 1 vertical on 3 horizontal. For a length of 353 feet the bottom width is 150 feet;

then follows a 500-foot long transition to a bottom width of 88 feet into the upstream dam embankment. A recorder well intake is located on the right bank of the channel. (See drawings 133/3 and 133/25 of Exhibit B.)

16. Control house.-- The control house, constructed of reinforced concrete, is an integral part of the control tower. The overall in side dimensions are 50 feet long by 25 feet wide and 24 feet high.

The elevation of the floor is 726.0 feet. The structure contains the hydraulic gate hoists, standby power unit, switchboard, gate position indicators, and overhead traveling crane and hydraulic oil tank. Access from the roadway on the crest of the dam to the control house is provided by a service bridge over the ogee of the spillway.

(See drawings 138/25 and 139/85 of Exhibit B.)

17. Trash racks.-- Four trash racks are provided on the upstream embankment in front of the outlet works. The arches supporting the trash racks are of reinforced concrete and form a rigid frame with the main structure. The vertical columns of the trash rack frames are restrained structural steel members. Individual trash rack units are removable. The bottom trash rack units have been omitted. The four bays of the trash racks are interconnected to allow free lateral flow of water between the racks and the discharge openings. (See drawings 137/38, 138/75, and 138/17 of Exhibit B.)

18. Outlet channel.-- Below the conduit outlet portals, transitional piers, 13 feet in length, are provided for smooth junction of the flow from the several conduits. Below the piers, the outflow is carried in a rectangular concrete channel, 83 feet wide, for a distance of 294 feet, thence through a 400-foot long transition to a channel width of 50 feet. The channel invert from the end of the portal piers to the lower end of the transition has a constant slope of 0.00924, which is sufficient to prevent backwater on the conduits and to insure smooth flow through the transition for the entire range of discharge. Below the transition, a 50-foot rectangular concrete channel extends ( 1,827.71 feet to join the Los Angeles River Channel. (See drawing 133/25 of Exhibit B.)

19. Foundation drainage.-- The foundation drainage for the outlet works and the spillway is described as follows:

a. Upstream apron.-- Uplift pressure on the 50-foot wide upstream apron of the outlet works and spillway ogee is relieved with 4-inch diameter weep holes at approximately 15 feet center to center each way.

Under each weep hole is a 2-foot cube of graded gravel. The filter formed by the gravel allows the passage of water but hinders the inflitration of fine material.

b. Outlet channel.-- The walls of the outlet channel are protected from ground water pressure with weep holes. The invert is protected with weep holes and longitudinal 12-inch open joint tile drains. The weep holes are backed up by graded gravel pockets. The open joint drains are surrounded by approximately 12 inches of graded gravel and empty into the outlet channel through subdrain risers protected with hoods.

c. Ogee section.-- The foundation of the ogee section is drained with an 18-inch open tile drain surrounded with approximately 30 inches of gravel. The drain runs the length of the spillway and is placed under the downstream toe of the ogee. It empties by gravity into the outlet ch anne 1 downstream of the outlet works. A flap gate on the end of the drain prevents the possibility that high water in the outlet channel might back up into it. This drain intercepts practically all of the water percolating under or through the ogee cutoff.

d. Outlet works.-- A drain, similar in type and location to that under the ogee, protects the outlet works. It empties into the outlet channel through the subdrain risers. (

e. Downstream spillway slab.-- The 18-inch slab extending 500 feet downstream of the ogee section is underlaid with a 12-inch continuous gravel blanket. This gravel blanket is drained with transversed 8-inch open joint tile drains spaced at 30-foot centers. These drains empty into the outlet channel. This system of drainage gives complete and positive uplift protection to this slab. As weep holes are not used, the joints of the slabs are made leakproof with water stops.

f. Joint drains.-- The spillway is divided into a series of monoliths. The joints between these monoliths are made watertight with water stops. Behind these water stops and on the joints are 8-inch formed drains which will intercept any water that may pass the water stops. These drains empty into the outlet channel downstream of the outlet works. (See drawing 133/31 of Exhibit B.)

20. Fences.-- Safety guard fences are provided on top of the east wall of the spillway channel. They consist of 2-inch diamond mesh galvanized chain link fencing, 3 feet wide stretched tightly and secured firmly to 1-5/8-inch O.D. galvanized barbed wire. Galvanized steel tubing braces, 1-5/8-inch 0. D. are provided at changes in grade or alignment.

The posts and braces are cement grouted in 2-inch diameter black pipe sleeves. (See drawing 137/37 of Exhibit B.)

21. Inspection and maintenance.-- The Dam Operator or his alternate shall inspect each year, before the flood season starts, the interior of the outlet works structure and the full length of the outlet conduits and shall complete an inspection check list as shown in Exhibit F.

In addition to inspections and maintenance work described in Part II, paragraph 8, and applicable to this section, the Dam Operator shall perform maintenance work on the following:

a. Channels.-- Channels shall be kept free of driftwood, trash, silt, and other debris. Driftwood, brush, weeds, and any other combustible trash and incombustible accumulations shall be hauled away and dumped in approved disposal areas.

b. Weep holes.-- All weep holes shall be kept clean and open.

Plant growth, bird nests, and animal den accumulations shall be re moved from the weep holes, using a piece of heavy wire bent into a hook at one end. Weed killers will discourage plant growth. Silt deposits shall be removed from the holes by flushing with a hose and nozzle.

c. Fences.-- Maintenance of the safety guard fences shalt in clude (1) line posts firmly set and gates hung in good alignment; (2) barbed wire tight and broken strands repaired; (3) corner posts, gate posts, and braces firmly set; (4) posts, braces, and gates that require paint properly brush-painted; (5) chains and locks attached to all gates; and (6) gate keys available at the Dam Operator 1s house to permit authorized travel throughout the property.

Spillway

22. Description.-- The spillway structure is located near the center of the dam over the old Los Angeles River Channel. The approach channel is excavated to elevation 680. The crest is a Creager and Justine ogee section with a 1 on 1 sloping upstream face. The crest at elevation 700 has an overall length of 459 feet, consisting of 7 bays at 57 feet each, and 6 crest piers 10-foot wide. The piers support a bridge and provide space for crest gate operating equipment. A concrete-lined rectangular (-channel below the crest, 469 feet wide,is constructed downstream approximately 320 feet below the toe of the embankment. A 40-foot steel sheet piling cutoff wall and a 200-foot long derrick stone section, extending to a maximum depth of 20 feet, is located at the end of the concrete channel. For protection against undermining of the outlet works channel, steel sheet piling, penetrating to a depth of 25 feet, and extending a distance of 400 feet downstream from the spillway, is provided under the left wall of the outlet channel. (See drawings 133/25 and 133/26 of Exhibit B.)

23. Walls.-- Retaining walls are provided at each end of the spillway structure and one on each side of the spillway and outlet channels. The retaining walls are of the counterfort and cantilever type design. The counterfort walls downstream from the spillway are on piles. (See drawings 133/24 through 133/27 of Exhibit B.)

24. Slabs.-- The invert slabs, except those integral with the walls, may be grouped into three sections as follows: (1) The upstream apron slab is 18 inches thick and provided with a 6-foot cutoff. (2) The horizontal section of the invert slab downstream from the ogee is 18 inches thick and drained directly in the outlet channel by means of lateral tile and gravel drains. (3) The horizontal section of the invert slab below the control structure is 18 inches thick and drained by means of longitudinal tile and gravel drains. Weep holes and gravel drains are provided to relieve the uplift. (See drawings 133/25 and 133/27 of Exhibit B.)

25. Spillway bridge.-- The design of the bridge is architecturally pleasing, economical of material, and capable of successfully resisting earthquake shocks and wide temperature changes without affecting the spillway ogee of which it is an integral part. The reinforced concrete bridge is 459 feet long, 18 feet wide and consists of seven rigid frame spans. The 12-foot wide roadway for vehicular traffic is flanked ( by 3-foot wide curbs with pipe railings 3 feet 4~ inches overall height. _ (See drawings 133/26 and 133/27 of Exhibit B.)

26. Location of controls and access tunnel.-- Floatwells and crest gate control chambers are located in the bridge piers; access to control chambers is by vertical shaft and ladder from the bridge curb, elevation 725.75, at each pier. An access tunnel 7 feet 3 inches high, 4 feet wide and about 466 feet long, running the entire length of the spillway section, interconnects the gate control chambers and the control house. Manholes in the access tunnel and gate control chambers afford access to the gate retess for maintenance and repair.

(See drawing 133/27 of Exhibit B.)

27. Inspections and maintenance.-- The Dam Operator or his alternate shall perform periodic inspections and maintenance according to Part II, paragraph 8, and shall complete inspection check list as shown in Exhibit F. The spillway shall be inspected at least once each year during the dry season. Inspection and maintenance of concrete and derrick stone structures, channels, and weep holes, and the elimination of hazardous obstructions have been previously described. The surface drains on each side of the spillway shall be kept free from weeds, trash, and accumulations of soil from the excavated banks. Broken or displaced concrete shall be promptly repaired.

Slide Gates and Crest Gates

28. Slide gates.-- The main service gates are of the slide type and are 6 feet wide by 9 feet high. The gate speed is approximately one-foot per minute. Total weight of each of the 4 slide gates with gate hanger assembly is approximately 115,840 lbs. (Moving parts of one gate is 13,000 lbs.) Maximum gate travel is 9 feet 5/16-inches.

Under normal conditions the gates remain open. Each cast iron gate leaf is designed to withstand all actual stresses with sufficient section to minimize casting and machining difficulties, and with web depth adequate for the proper attachment of the gate leaf stem. The gate leaf and the gate leaf guide are provided with bronze strips.

The bottom gate leaf seal is of high-grade rubber; the gate leaf stem of copper-nickel alloy and the bronze gate stem nuts are of ample capacity to raise and lower the gate. The bonnet cover is a steel casting; the hoist cylinder consists of a pierced and rolled steel forging with butt-welded forged steel flanges; the hoist cylinder piston is cast iron; the gate leaf stem extension is of nickel-copper aluminum alloy. (See drawings 138/27 and 138/28 of Exhibit B.)

29.- Slide gate control.-- The slide gates are hydraulically con trolled from a manually operated valve manifold-located in the control room. A motor driven high pressure rotary pump supplies oil to the gate operating cyclinders. An identical spare unit is provided to insure continuous operation in the event of failure of the pump in service. The entire system operates full of oil at all times.

Relief valves and an air shock absorber chamber are provided in the pressure control system to prevent the development of excessive pressure.

An oil storage tank of 200 gallons capacity is installed near the pumps in the control room. Pump capacities and efficiencies are based on hydraulic oil having a viscosity of 172 SSU at 100°F. For operation of slide gates see Exhibit H.

30. Automatic gate hangers.-- Locking of the four gates at any desired position between and including fully open and fully closed is accomplished by hydraulic automatic gate hangers mounted on the c· head of the gate operating cylinders and controlled by the oil pressure which operates the gates. The locking device consists of clamping jaws actuated by heavy coiled springs. Upon the admission of oil under pressure to the gate hanger, these clamping jaws release the gate stem, allowing the gate to be.raised or lowered as desired;

but as soon as this pressure is relieved by the opening of the gate operating valve at the valve manifold in the control room, the clamping jaws again grip the gate stem, locking the gate 1n position pending further manipulation. Visual indication to the operation of the proper functioning of the automatic gate hanger is afforded by a signal light mounted on the gate indicator panel in the control house. (See drawing 138/28 of Exhibit B.)

31. High pressure oil lines_.-- The high pressure oil 'lines are welded throughout. The fittings rated at 600 lbs.(cold water or oil non-shock) provide an ample margin of safety for any excess pressure due to hammer caused by stoppage in the lines or the too rapid closing of a control valve. Pipe is supported at such location and in such a way as to render unnecessary the use of expansion joints. All pipe lines are flanged at suitable intervals to permit easy removal of piping should the necessity arise. (See drawings 138/26 and 138/27 of Exhibit B.)

32. Gate air vents.-- Air vents are provided for admission of large quantities of air near the downstream face of each gate leaf in order to prevent creation of a vacuum and to keep the walls of the water passages free from cavitation effects. Two vertical vent pipes, 2 feet 2 inches in diameter, extend between the air intakes in the downstream wall and the ducts in the gate chamber. The in takes are located at elevation 715.5 and consist of circular openings protected by grills of bronze wire meshing. (See drawings 138/28 and 137/85 of Exhibit B.)

33. Crest gates.-- A sector type drum gate, 57 feet long and 10 feet high, is installed in each of the seven 57-foot clear openings between 10-foot wide piers. These gates permit storage of water in the reservoir to elevation 710 when the crest gates are in the raised position. The gates permit discharge of flood waters at elevation 700 when in a lowered position. The gates are designed for a net lift of 10 feet and are constructed of structural steel.

The weight of each gate is approximately 100,000 lbs. for a complete gate assembly. Each gate is hinged on castings anchored along the downstream side of the gate recess. When the gates are in lowered position, they rest on stops located at the bottom of the gate recess. The top surface of the gate conforms to the outline of the spillway ogee. (See drawings 138/5 and 137/78 of Exhibit B.)

34. Crest gate control.-- Gate control is a combination of manual and/or full automatic operation. Under automatic operation water flows through the inlet pipe into the gate recess as the reservoir fills. When the water in the recess reaches approximate elevation 692.5, the gate commences to float and will rise approximately 5 feet ahead of the reservoir level until the gate reaches the maximum raised position, elevation 710. When the level in the reservoir reaches elevation 712, the level of the water in the control valve float chamber will be approximately the same and the float will begin to rise. The float then opens the control discharge valve, the dis charge from the gate recess exceeds the inflow, and the gate begins to descend. If the water in the reservoir continues to rise, the gate will be lowered completely at such a time as the reservoir level reaches elevation 715. In the event that the balanced valve fails to function properly, the gate recess may be emptied by the use of a manually operated valve provided for this purpose. (See drawings 137/77, 137/78, 138/5, and 139/48 of Exhibit Band Exhibit I.)

35. Crest gate operation.-- Under normal operation the gates are entirely automatic and depend upon the principle of buoyancy to rise and descend. The gate is floated to the raised position by the admission of water to the gate recess and is lowered by draining the recess through a valve which is operated automatically or manually.

The maximum rate of rise of the reservoir is 6 feet per hour and the gates rise at approximately the same rate. Assuming all seals being intact and all leakage at a minimum, the gates can be lowered in about 15 minutes. The gate recess is connected to the reservoir by an inlet pipe that includes a manually-operated valve for emergencies.

The discharge from the gate reservoir is through a combination float and manually-operated, balanced valve. This balanced valve is by-passed by an 18-inch manually~operated gate valve as a safety measure in case the balanced valve becomes inoperative. City water, piped into the dam through suitable control valves, permits operation of the gates for inspection, testing, or in an emergency. Manholes are provided for access to the interior of the drum gates for inspection and repair.

Facilities are provided for draining the drums, should any leakage occur. (For crest gate operation, see Exhibit I.)

36. Inspections, tests, and maintenance.-- The Dam Operator or his alternate shall perform periodic inspections, tests, and maintenance as described in Part II, paragraph 8, and shall complete inspection check lists as shown in Exhibit F, and a test-operation report for service gates as shown in Exhibit G. l~aintenance work pertaining to service gates is described in the following paragraphs:

a. General.-- The gate and hoist assemblies shall be maintained in the best possible operating condition. They shall be tested once every month and a report (Exhibit G) shall be submitted to the Chief, Engineering Evaluation and Inspection Section, through the Maintenance Section. Repairs, which shall be made by electricians and mechanics from the Maintenance Section, shall conform to the standards in the contract specifications for the original work. Loose, damaged, unserviceable, or missing parts shall be promptly tightened, repaired, or replaced. (

b. Gates.-- Gates must come to a true watertight closure against the bottom seals. Each gate shall stop automatically at the fully open position and shall close tightly without shock. The Chief, Operations Branch, shall be notified, whenever the gates fail to close tightly or the seals are damaged. Gate seal surfaces shall be kept clean and free from rocks or other obstructions. To minimize the adhesion of abrasive dust and sand, the gate seals and frame seals shall never be lubricated.

c. Hoists and motors.-- The hoists and motors shall be kept properly lubricated and maintained by qualified personnel from the Maintenance Section. Each motor assembly shall operate smoothly and without abnormal noise or vibration. Each bearing shall be checked once a year by pumping grease into each fitting while the drain plug is removed. Removal of the drain plug, while pumping grease, prevents excessive pressure and injury to the grease seals.

d. Crest gate hinge bearings.-- The bearings, housed in castings of the crest gate hinges, shall be lubricated every year before the rainy season by inserting grease into the fittings located at each bearing.

Every five years the bearings shall be thoroughly cleaned by removing the coverplates, washing out the old grease and refilling with fresh lubricant. The cover plate is then replaced and, if necessary, repainted.

The cleaned sealing surface should be resealed with varnish or equivalent.

e. Painting.-- Painting of exposed metal surfaces shall be dones as required. Surfaces shall be thoroughly cleaned before painting; oil and grease shall be removed with suitable solvents and clean cotton rags, rust spots and loose paint with stiff wire brushes. Paint shall be applied in a workmanlike manner and in accordance with the applicable paragraphs of the original construction and supply specifications. Gates, sheaves, trash racks, and other metal surfaces exposed to water shall be ( painted with rust preventives.

f. Hydraulic test.-- The crest gates shall have a…