21. Description of highway.-A highway will connect with the end of the construction highway being constructed under a separate contract and will descend by light grades to the crest of the dam on the Nevada side of the river, passing the top of the inclined freight elevator. After crossing over the canyon to the Arizona side on the roadway along the crest of the dam, the highway grade will rise to a terminus above the canyon rim, where it will connect with a State highway which, it is contemplated, will be constructed at a later date. It is contemplated that the length of the highway on the Nevada side of the river will be about 4,000 feet, with a maximum grade of 6 per cent, and the length on the Arizona side of the river will be about 1,400 feet, with a maximum grade of 8 per cent.

22. List of drawings.-The following drawings are made a part of these specifications: (94.101) 45—D—901—Colorado River basin—General map. 2. (24102) 45–D–902—Dam and appurtenant works—Location map. 3. (24.108) 45—D—903—Hydrograph of Colorado River—Lees Ferry. 4. (24104) 45–D–904—Hydrograph of Colorado River—Bright Angel. 5. (24105) 45–D–905—Hydrograph of Colorado River—Topock. 6 7 8

1

. (24.106) 45—D—906—Gage heights of Colorado River—Yuma (1878–1915).

. (24.107) 45—D—907—Hydrograph of Colorado River—Yuma (1902–1930).

. (24.108) 45–D–908—Black Canyon gaging station—Discharge curves.

9. (24109) 45—D—909—Profile and log of drill holes—Centerline of river.
10. (24.110) 45–D–910—Profile and log of drill holes—Line “U” 940.
11. (24.111) 45—D—911–Profile and log of drill holes—Line “U” 200.
12. (241.12) 45–D–912—Profile and log of drill holes—Line “D.”
13. (24113) 45–D–913—Profile and log of drill holes—Line “D” 200.
14. (24.114) 45—D—914—Profile and log of drill holes—Line “D’’ 400.
15. (24115) 45–D–915—Profile and log of drill holes—Line “D” 600.
16. (241.16) 45–D–916—Profile and log of drill holes—Line “D” 1000.
17. (24.117) 45—D—917—Area and capacity curves—Black Canyon dam site.
18. (241.18) 45—D—918—Government space reservation.
19. (24119) 45–D–919—Mass concrete yardage.
20. (24.120) 45—D—920–Construction progress chart—By features.
21. (24121) 45–D–921—Construction progress diagram—Pictorial.
22. (241.22) 45–D–922—Dam and appurtenant works—General layout.
23. (24123)45–D–923—Dam and appurtenant works—Sectional elevation.
24. (241.24) 45–D–924—Maximum section of dam–Grout and drainage system.
25. (24125) 45–D–925—Contraction joint layout–Plan and sections.
26. (24.126) 45–D–926–Contraction joint layout—Detail perspective.
27. (24197) 45–D–927–Grouting system layout. -
28. (24128) 45–D–928—Cooling system layout.
29. (24.129) 45—D—929–Shafts and galleries.
30. (24.130) 45—D—930—Parapet and roadway.
31. (24181) 45—D—931—Tunnel alignment layout.
32. (24.182) 45—D—932—Upper and lower tunnel plug adits.
33. (94.133) 45–D–933—Profiles and sections—Spillway tunnels.
34. (24.134) 45—D—934—Profiles and sections—50-foot penstock tunnels.
35. (24.135)45–D–935—Profiles and sections—30-foot penstock tunnels.
36. (24.136) 45–D–936—Outer diversion tunnel portal-Inlet structure.

37. (24137)45–D–937—Outer diversion tunnel portal–Concrete bulkhead,

38. 39. 40. 41. 42. 43. 44. 45. 46. 47. 48. , 49. 50. 51.

52.

53. 54. 55. 56. 57. 58. 59. 60. 61. 62. 63. 64. 65. 66. 67. 68. 69.

70.

71.
72.
73.
74.
75.
76,

(94.188) 45–D–938—Inner diversion tunnel portal—Trash rack structure.
(2/139) 45–D–939—General plan and sections—Arizona spillway.
(24140) 45—D—940—General plan and sections—Nevada spillway.
(24141) 45–D–941—Spillway tunnel plug-Typical design.
(241/2) 45—D—942—Spillway tunnel portal—Outlet structure.

(24143) 45—D—943—Upstream plug outlet works—Nevada side.

(24144) 45–D–944—Upstream plug outlet works—Arizona side.
(24.145) 45–D–945—Upstream plug outlet works-Reinforcing details.
(24146) 45–D–946–Upstream plug outlet works—Gate installation.
(94.147) 45—D—947—High pressure emergency gates—General assembly.
(24148) 45—D—948–Canyon wall outlet works—Typical design.
(24149) 45–D–949–Canyon wall outlet works—Sections—Arizona side.
(24.150) 45—D—950–Canyon wall outlet works—Sections—Nevada side.
(94151) 45–D–951—Canyon wall outlet works—Reinforcing details—Elevation
945.
(94.152) 45–D–952–Canyon wall outlet works—Reinforcing details—Elevation
820. - -
(24153) 45–D–953–Canyon wall outlet works—Gate and valve assembly.
(94.154) 45–D–954—Downstream plug outlet works—Typical design. .
(24.155) 45–D–955—Downstream plug outlet works—Gate and valve assembly.
(24156) 45–D–956–50 foot by 50 foot Stoney gate—Typical design.
(24167) 45–D–957–50 foot by 50 foot Stoney gate—Leaf assembly.
(24.158) 45–D–958–50 foot by 50 foot Stoney gate—Hoist assembly.
(24159) 45–D–959–50 foot by 50 foot Stoney gate—Counterweight assembly.
(24.160) 45–D–960–Cylinder gate intake towers—Typical design.
(34161) 45–D–961–Cylinder gate intake towers—Concrete bridge.
(24163) 45–D–962–Cylinder gate intake towers—Cylinder gate assembly.
(24,168) 45–D–963–Cylinder gate intake towers—Gate-hoist assembly.
(34164) 45–D–964–Hoover power plant—Elevations. *
(34165) 45–D–965–Hoover power plant—General plan.
(34166) 45–D–966–Hoover power plant—Typical wing sections.
(24! 67) 45–D–967–Hoover power plant—Partial wing plans.
(34168) 45–D–968–Hoover power plant—Central section.
(84.169) 45–D–969–Hoover power plant—Central portion floor plans—Above
elevation 710.

(24.170) 45–D–970–Hoover power plant—Central portion floor plans—Below

- elevation 710. -
(34171)45-D-971–Hoover power plant—Structural steel details.
(84.17%) 45–D–972–Hoover power plant—Section through penstock tunnels.
(84.173) 45–D–973—Inclined freight elevator. -

(34174) 45–D–974–Passenger elevator layout.
(34175) 45–D–975—Black Canyon highway.

(34.176) 45–D–97 6-Canyon cross sections.

The drawings show the general arrangement of all features. Where required, as determined necessary by the contracting officer, additional drawings showing details of the work will be fur. to the contractor during the progress of the work. The contractor will be furnished such additional copies of the *Pecifications and drawings as may be required for carrying out the work.

Contact prints of the original drawings from which the attached reductions were made will be furnished to the contractor for construction purposes upon request. Two reproductions from photographs (Plates 1 and 2) are included in these specifications. The reproductions show the topography and general nature of the site of the work. Prior to the reproduction of the photographs, the dam and other features were sketched thereon as they may appear after completion. 23. Preference rights of ex-service men and citizens of the United States.—The contractor and/or his subcontractor or subcontractors shall, so far as practicable, give preference at the time of employment, first, to qualified persons who have served in the United States Army, Navy, or Marine Corps during the War with Germany, the War with Spain, or in the suppression of the insurrection in the Philippines, and who have been honorably separated or discharged therefrom or placed in the Regular Army or Navy Reserve, and second, to qualified citizens of the United States. 24. Commencement, prosecution, and completion of work.-The contractor shall begin work within thirty (30) calendar days after date of receipt of notice to proceed. Each part of the work shall be completed within the number of calendar days after the date of receipt of notice to proceed as follows: - ^ (a) All that portion of the two wings of the power house sufficient to permit installation of the 6 upstream power units on each side of the river;+he-pertier ae—building—e #g—#ke—t wings; the substructure of the power house, for installation of two additional power units on each side of the river immediately downstream from the other power units, up to elevation 660; and all other portions of the power plant and other works which must be completed before the necessary power machinery and other equipment to be installed by the Government for the operation of power units N1, N3, N5, A1, A3, and A5 can be placed, within one thousand six hundred (1,600) calendar days. (b) All other portions of the dam, power plant, and appurtenant works which will permit, without damage to any part of the required works, the permanent storage of water up to a maximum elevation of 935 and the operation of power units N1, N3, N5, A1, A3, and A5, within one thousand nine hundred and sixty-five (1,965) calendar days. (c) All of the remainder of the work under the schedule, including the completion of th power house and power plant for 6 power units on each side of the river, within two thousand five hundred and sixty-five (2,565) calendar days: Provided, That if the Government gives the contractor written notice within one thousand six hundred (1,600) calendar days, after date of receipt of the original notice to proceed, that a total of 7 or 8 power units will be required on each side of the river, instead of 6, then the work required for the additional units shall be completed within the same period, i. e., within two thousand five hundred and sixty-five (2,565) calendar days. The contractor shall at all times during the continuance of the contract prosecute the Work with such forces and equipment as, in the judgment of the contracting officer, are sufficient to complete it within the specified periods of time. 25. Liquidated damages.-The damages that may result from any delay in completion of any part of the work by the time agreed upon will be difficult, if not impossible, of ascertainment. If any part of the work is not completed on or before the date fixed for its completion by the terms of the contract, the contractor shall pay to the Government as fixed, agreed, and liquidated damages the sum of three thousand dollars ($3,000) per day for each part of the work, as Subdivided in paragraph 24 for each calendar day's delay until it is satisfactorily completed or until such time as the Government may reasonably procure the completion of the work by another contractor or complete the work itself. Whatever sums may be due as liquidated damages for delay may be deducted from payments due to the contractor or may be collected

from the contractor or the contractor's Surety or sureties. The provision for liquidated damages shall not prevent the Government from terminating the right of the contractor to proceed in

case of default, as provided in article 9 of the contract. - 26, construction program.-The construction program shall be at all times subject to the approval of the contracting officer. The capacity of the construction plant, sequence of operations, and methods of operation shall be such as to insure the completion of the work within the periods of time of completion specified. The construction program shall meet all the requirements of these specifications in connection with the stripping of the canyon walls of loose rock; the construction of the diversion tunnels, cofferdams, and other diversion Works; excavations for foundation; sequence in placing concrete; installation of gates and the control of river flow; grouting of contraction joints; and other parts of the work. A tentative construction program has been outlined by the Government, which, if followed, would permit all parts and features to be completed as specified in paragraph 24, and is shown on the drawings. This program assumes that the date of receipt by the contractor of notice to proceed will be April 15, 1931. It calls for completion of the diversion tunnels by October 1, 1933; the cofferdams by May 1, 1934; and the placing of the first mass concrete in the dam not later than December 1, 1934. It contemplates that the construction of all necessary features for the beginning of storage of water by June 15, 1936, and of all other necessary features for the generation of power, as provided in paragraph 24, by September 1, 1936, with the storage of water to elevation 935, will be completed by the required dates. The necessary features include installing the Stoney gates in the outlets of the inner diversion tunnels; placing the upstream tunnel plugs, with high-pressure slide gates for temporary use, in the inner diversion tunnels during the fall of 1935; constructing the bulkheads for the inlets of the outer diversion tunnels, lowering the bulkheads into position by June 15, 1936, and constructing the solid tunnel plugs in the outer diversion tunnels immediately thereafter; completing portions of the power house and other work as specified in paragraph 24 (a), by September 1, 1935; completing the intake towers and appurtenant parts, except the bridges, by July 1, 1936; and completing the entire canyon-wall outlet works connected with the downstream intake towers by September 1, 1936. Although the tentative construction program calls for completion of the spillways by November 1, 1933, this date could be postponed a year or more, but the spillways and the concrete in the dam, except the parapets, should be completed by such dates as will permit ample time for building up the storage to the spillway crests; the construction of the downstream plugs, including the installation of the needle valves therein and the construction of the canyon-wall outlet works connected with the upstream intake towers; and other work required before the date of completion of the contract, the construction of which is dependent on the prior completion of the spillways. It is contemplated that, if required, the completed upstream intake towers and the tunnel plug and downstream canyon-wall outlet works will serve as spillways in passing the flood water of 1937, and possibly a portion of the flood water of 1936. The construction program shown on the drawings is tentative only and the Government assumes no responsibility for any use that bidders or the contractor may make of this program or for any deductions or conclusions that may be made by them from the study thereof. It is included in the specifications solely to assist bidders and the contractor in preparing their 9Wh construction programs, and takes into consideration work which has been, or will be pero o o or by the Government. None of the statements in this paragraph, o o o so. program, shall reliev € the contractor from the

27. Materialso no i. o o: Complete the work as provided in paragraph 24.

use in concrete gro ut it y d e Government—The Government will furnish cement for 3 8", and mortar; reinforcement bars, rails, and fabric; anchor bars, rods, and bolts; metal pipe and fittings; conduit lining castings and plate-steel conduit linings for power penstocks and outlet works; copper sheets and rivets for contraction joints and other seals; gates and hoists; needle valves; traveling cranes; operating machinery; structural steel for trash racks, bridges, and other structures; sheet piling; rails and structural-steel guides for the inclined freight elevator; pipe for hand railings; all necessary doors, windows, and hardware except as otherwise provided; metal floor plates and stairways; steel partitions; fabricated parts for sheet metal work; metal lath, hair or fiber, and hydrated lime for lath and plaster wall; paint materials; plumbing and hardware; hollow tile, lime putty or plastic fire clay, and white Portland cement for hollow-tile walls; ceramic tile for walls and floors; roofing materials except back fill; corrugated metal pipe and coupling bands for highway drains and culverts; resistance thermometers; electrical conduits; forms for concrete relief work as provided in paragraph 122; well casing and steel pipe forms for concrete bulkhead gate supports as provided in paragraph 116; and all other materials not specifically mentioned in this paragraph or in paragraph 28 that will become a part of the completed construction work. All materials furnished by the Government will be delivered to the contractor f. o. b. cars at the delivery yard near Boulder City as shown on the location map and further described in paragraph 40 for construction railroad. The contractor shall haul all such materials from the point of delivery to the work, shall provide suitable warehouses or other means of protection satisfactory to the contracting officer for such of the materials as, in the opinion of the contracting officer, require storage or protection, and will be charged for any materials lost or damaged after delivery, except as otherwise specifically provided, the same amounts that the materials cost the Government at the point of delivery to the contractor. The contractor shall be responsible for the prompt unloading of material delivered and the proper care of the materials, and will be held liable for any demurrage charges incurred due to failure to unload cars promptly, and for any rental or other charges incurred on rolling stock while in the possession or under the control of the contractor. The contractor shall report to the contracting officer in writing, within 24 hours after unloading, any shortage or damage to materials when delivered. The cost of unloading, hauling, storing, and caring for all materials furnished by the Government for use or installation by the contractor shall be included in the prices bid for the work in which the materials are to be used. The cost of handling and installing minor miscellaneous items of timber or other work, except metal work, for which specific unit prices are not provided in the schedule shall be included in the unit prices bid for the work to which they are appurtenant. The contractor shall return to the Government at the delivery yard, at the dam site, or at any point on the construction railroad, as directed by the contracting officer, all unused materials, and will be charged for any materials not used and not returned the same amounts that the materials cost the Government at the point of delivery to the contractor. 28, Materials to be furnished by the contractor.—The contractor will be required to furnish all sand, broken rock or gravel, and cobbles for concrete; sand for grout, sand blasting, gunite, and mortar; stones for rubble-masonry walls; all form materials, including oil for oiling forms, except as otherwise provided in paragraph 122; all lumber for temporary timbering in tunnels, shafts, and adits, if required, and for stop planks for inlet of inner diversion tunnel; steel liner plates, steel ribs, and arch ring segmental bars or I-beams for tunnels, if required; all spikes and nails for forms and other uses; all wire, wire ties, or other appliances used for holding forms and for securing reinforcement steel; all embankment and back-fill materials; all water used for mixing, cleaning, and curing concrete, for grouting, for cooling plant and accessories, and for drinking purposes at the site of the work; joint compound for joints in gate control piping and cooling pipes; pipe and fittings not required for the permanent installations; oakum or other suitable