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lines were run for a high-line canal south of the sand hills through Mexican territory. - (d) In 1913 the Imperial irrigation district made a preliminary survey for an all-American aqueduct of a capacity of about 3,667 second-feet through the sand hills. This survey followed along and parallel with the international boundary from a point just west of the Hanlon Heading to a point near the present East High-Line Canal. (e) In 1916 and 1917 the Imperial-Laguna Water Co. made surveys for an all-American canal along practically the same route followed by the Imperial irrigation district in 1913, except it only extended westerly to a point where the msea lands could be served. The early plans of this company contemplated a canal of 1,865 second-feet through the sand hills. Later the company planned a larger canal, but of a much less capacity than the canal here planned. (f) The data and maps of these different surveys were available and have been made use of in making the surveys and estimates.

4. SURVEYS.

(a) In 1917 a survey was made by the Reclamation Service for a power canal from Siphon Drop to a proposed power site near Araz. Very careful and complete topography had been taken over this section. The year prior cross sections had been taken on the main Yuma Canal from Laguna Dam to Siphon Drop. It was found that we could use all of this work, and therefore the Survey was taken up at the end of the proposed power canal near Araz and extended southwesterly to a point on the east side of Pilot Knob, where we found it would be necessary to either cut or tunnel through a narrow rock spur of Pilot Knob for 800 feet in order to avoid interfering with the quarry of the Imperial irrigation district. From this point the line continues in the same general course to a point 400 feet north of the international boundary, and thence parallels the boundary to a point well within the blow-sand area. From this point the line runs to the northwest, keeping well on the mesa floor among small sand dunes not exceeding 12 or 15 feet in height. At a point about 2 miles north of the international boundary the line takes a southwesterly course through an open mesa for more than a mile, and then again swings to the northwest over a high blow sand ridge 3,000 feet across, into what is locally known as Government Gap. From the western end of Government Gap the line takes a southwesterly course, crossing two main sand ridges which total about 1% miles to reach the mesa on the west of the blow-sand hills; thence on the same general course until it reaches a point 400 feet north of the boundary line: thence along the boundary to monument No. 213, where the line runs somewhat north of the boundary, keeping generally a westerly course in order to take advantage of the topography of the ground. As the line nears the East Side High-Line Canal it again approaches the boundary and follows along it to the west side main except for a detour in order to get around the city of Calexico and to obtain a better crossing of New River. (b) Through the blow-sand area two alternate routes were surveyed, one along the boundary, which is about 1% miles shorter than the line above described, but containing 1,800,000 cubic yards more excavation, and the other to the north of the adopted line and being for the purpose of avoiding the first big sand ridge described above. This latter line is nearly a half mile longer and contains 200,000 cubic yards less excavation. (c) Topography was completed and extended on the section south of Pilot Knob, and a strip of topography 2,000 feet in width was taken on the lines through the sand hills. Additional topography was taken at Laguna Dam, along the Southern Pacific tracks near Araz, Alamo River, and New River crossings. (d) All the topography taken and available was plotted on a scale of 400 feet to the inch. This is shown on 37 sheets, which are on file in the Yuma office. A profile of the canal from Siphon Drop to the West Side Canal on a scale of 500 feet to the inch is also on file in the Yuma office.

5. IRRIGABLE ACREAGE.

(a) The irrigable acreage of the Imperial irrigation district now within the district boundaries is about 515,000 acres, all of which could be reached by gravity through an all-American canal, with the exception of two or three sections near the international boundary west of New River, upon which it will

be necessary to pump the water. The West Side Main Canal can be made to serve another possible 40,000 acres.

(b) In the East Side mesa district there is estimated to be 140,000 acres, and to the north of the Southern Pacific Railroad, east and north of the Salton Sea, including the Coachella Valley, there is another 200,000 acres, making a total of 895,000 acres that can be served by a gravity system.

(c) In consultation with the Board of Engineers it was decided to adopt 900,000 acres as the basis upon which to make the estimates.

6. WATER DUTY.

(a) With as large an acreage as it is here contemplated to serve, and the fact that a considerable portion of the irrigable acreage has been under irrigation for some years, it was deemed that a diversion duty of 1 cubic foot to 100 acres was sufficient.

(b) The losses in the canals are not anticipated to be excessive after they are thoroughly seasoned. It is estimated that there will be delivered to the land 75 per cent of the amount diverted.

6a. CANAL SECTIONS AND CAPACITIES.

(a) With the above duty, 900,000 acres will require a diversion at Laguna Dam of 9,000 second-feet in addition to the amount required for the Yuma project of 1,600 second-feet or a total of 10,600 second-feet from Laguna Dam to Siphon Drop.

(b) All the larger sections of the canals were designed to give a velocity of 3.5 feet per second when running full and 2.5 feet per second or better when running at half capacity.

(c) Below are given some of the dimensions of principal sections of the canal from Laguna Dam to the West Side main canal. The types of the cross sections are shown on the profile. These are marked " sections" and numbered both on the “ section” and on the profile to which that “ section” applies.

1. The 'canal from Laguna Dam to Siphon Drop will have a bottom width of 162 feet, a depth of 16 feet, side slopes of 2 to 1 on the lower side and 11 to 1 on the upper side, a grade of .0000792, and a carrying of 10,640 second-feet.

2. From Siphon Drop to the sand hills the bottom width will be from 146 to 164 feet, a depth of 15 feet, side slopes from 11 to 1 to 2 to 1, a grade of .0000786 to .0000862 and an estimated carrying capacity of not less than 9,000 second-feet. The different widths, slopes, etc., are due to the different cross sections adopted to fit the varying character of the material to be excavated.

3. Through the sand hills the bottom width is 146 feet, a depth of 15 feet, side slopes 2 to 1 with a berme of 30 feet on either side at the surface of the mesa floor, which is the base of the sand dunes, a grade. of .0000813 and a carrying capacity of 9,000 second-feet.

4. From the west side of the sand hills to Mesa Canal No. 1 the dimensions are the same as those used from Siphon Drop to sand hills.

5. Mesa (anal No. 1 to Mesa Canal No. 2 the bottom width is 125 feet, a depth of 12 feet, side slopes 11 to 1, a grade .00012 and a carrying capacity of 6,006 second-feet.

6. From Mesa Canal No. 2 to the East Side main canal a bottom width of 113 feet, a depth of 12 feet, side slopes 11 to 1, a grade of .00012 and a carrying capacity of 5.502 second-feet.

7. From the East Side main canal to near Allison Heading, a bottom width of 108 feet, depth of 105 feet, side slopes 11 to 1, a grade of .00014 and a carrying capacity of 4.546 second-feet.

8. From near Allison Heading to the Alamo River, a bottom width of 93.5 feet, depth 10 feet, side slopes 11 to 1, a grade of .000156 and a carrying capacity of 3,797 second-feet.

9. From the Alamo River to the Central main canal a bottom width of 82 feet, depth of 9.5 feet, side slopes 11 to 1, a grade of .00017 and a carrying capacity of 3,199 second-feet.

10. From the Central main canal to the West Side main canal, a bottom width of 46.5 feet, depth 8 feet, side slopes 11 to 1, a grade of .0002 and a carrying capacity of 1.495 second-feet.

(d) No diminution has been made in the canal sections in this preliminary estimate, due to the loss of water, as we get farther away from the dam, as occasional storm waters must be cared for in the canal and it was thought

best that the lower stretches of the canal should be over rather than under sized. The canal banks from Laguna Dam to Pilot Knob have been designed to give a 6-foot freeboard, in order that ample capacity may be provided to carry all possible storm waters without endangering the canal.

7. STRUCTURES.

(a) All the structures along the line of canal are planned to be of concrete and steel. The approximate location of the several structures is shown on the map attached to this report. The cost of the structures is given under the heading “ Estimates of Cost." Pencil sketches of the several types of structures have been prepared as a basis for estimates and are on file in the Yuma office. A brief statement of the type of structure is as follows:

(1) Laguna Dam and Sluiceway Improvements.--It is contemplated to raise the crest of Laguna Dam 2 feet, if after a thorough study of the conditions this is deemed safe and advisable. The grades and sections of the canals are based upon the assumption that it is practicable to make this addition to the dam. The sluiceway and regulating gates are to be of the same type as those now in use, but are to be enlarged to handle 10,600 cubic feet. It is contemplated to add another Stoney gate of the same size as the three now in use.

(c) Waste gates.-At a point about 7,000 feet below Laguna Dam, near Araz and at Pilot Knob, waste gates of the Stoney type are planned, of sufficient capacity to drain the canal and to give a sluicing velocity. Wasteways are also provided for at the Alamo and New Rivers.

(d) Checks.-(hecks are provided below all the principal turnouts of the flashboard type.

(e) Turnouts.-All the turnouts from the main canal are planned of concrete with steel gates and appropriate lifting devices.

(f) Drops.—The location and height of drops are shown both on the map and the profile. These are of the inclined chute type. At two of the larger drops on the Mesa, plans are made for power development and designated as Mesa Power Plants Nos. 1 and 2. The small drop above Mesa Power Plant No. 1 may in the future be added to the drop at the power plant by raising the banks of the canal and the structures at Power Plant No. 1. No provision, however, has been made for this future work in the estimates.

8. UNIT costs.

In arriving at unit costs for this work in consultation with the board of engineers it was decided that costs should be based upon what this class of work could be done for under present conditions with standard equipment now in use upon work of like magnitude. The unit prices adopted and used are as follows: Earth excavation-Laguna Dam to Pilot Knob----------per cubic yar:1.- $0. 20 Earth excavation-Pilot Knob throught sand hill section.Earth excavation-for Mesa (cuts less than 35 feet) --Earth excavation--for structures Rock excavation.-.-Concrete (massive) --

15.00 Concrete (formed).

18.00 Concrete (Alamo and New River flumes

20.00 Reinforced steel (in place) -

--------------per pound.. .07 Right of way --

--------

----per acre- 100.00 Power plants -----

per turbine horsepower.. '90.00 Engineering and contingencies -

------per cent

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9. ESTIMATES OF COST.

(a) Estimates have been prepared and given below upon the basis, first: Of providing for the diversion of 10,600 cubic feet of water at Laguna Dam, to serve the Yuma project, the present Imperial Irrigation District and the avail. able new land which it is possible to irrigate.

(b) Second. For the diversion of 7,600 cubic feet of water at Laguna Dam, to serve the Yuma project and the Imperial Irrigation District. Ia this latter

1 Does not include penstocks, by-pass tail race, or excavation for the buildings.

estimate, all structures are estimated of a size and capacity sufficient for the larger development. Only such structures as are required solely for the purpose of placing water on the new land are omitted. The division of costs between the Reclamation Service (for the Yuma project) and the Imperial Irrigation District for the enlargement of the canal from Laguna Dam to Siphon Drop and the construction of a new canal from this point to the proposed power plant near Araz is fixed by the contract of October 23, 1918, between the Secretary of the Interior and the directors of the Imperial Irrigation District. This division of costs is taken into account in the final analysis. No division of costs has been attempted as between the Imperial Irrigation District lands and the Mesa lands. (c) Table of estimates of costs. (See accompanying sheets.)

Estimates—All-American canal of capacity to $erve Imperial irrigation district and additional Mesa lands.

Laguna Dam to Siphon Drop (canal capacity 10,600 second-feet):

Excavation— Earth —4,808,240 cubic yards, at 200___________ $961, 648 Rock—724,579 cubic yards, at 75c ------------ 543, 435 Total_______ - 1, 505, 083 15 per cent contingency----------------------- 225,762 $1,730,845 Structures— Alterations at Laguna Dam------------------- 745,000 Sluice about 1% miles below dam______________ 240,000 Turnout Reservation Canal_------------------ 10, 500 Check below T. O. Res. Canal_________________ 27, 500 Picache Road bridge------------------------- 34, 000 Raising Siphon Drop------------------------- 20,000 Walapai Lateral Turnout_______-------------- 7, 100 Check below Siphon Drop -------------------- 22,000 10 miles telephone line_-________________––––– 2, 250 Total —- --- 1, 108, 350 15 per cent contingency---------------------- 166,252 1, 274, 602 Imperial Valley—Cost of connection with Laguna Dam (contract of Oct. 23, 1918) ------------------- 1, 900,000 Total --- --- 1--------------------- 4, 905, 447 Siphon Drop to Araz (9,000 second-feet canal): Excavation— Earth—2,522,000 cubic yards, at 200-----_____ $504, 400 15 per cent contingency -------- — — — — — — — — — — — — — — 75, 660 - 580,060 Structures— Highway bridge ----------------------------- 34,000 Double track railway bridge at Araz siding---- 85,000 Highway bridge ––––––––––––––––––––––––––––– 34,000 Wasteway____ 235,000 Check- 22,000 Highway bridge ----------------------------- 34,000 5 miles telephone line------------------------ 1, 125 Total ------------------------------------- 445, 125 15 per cent contingency---------------------- 66,769 - 511, 894

Total ------------------------------------------------ 1, 891, 954

Araz to Pilot Knob (9,000 second-feet canal):
Excavation—

Total ------------------------------------15 per cent contingency----------------------

Structures—
Railway bridge
Sluiceway
Check
Highway bridge
3 miles telephone line------------------------

Total ------------------------------------

Pilot Knob to East Side Mesa Canal (No. 1 Sta. 1525)
(9,000 second-feet canal) :
Excavation—
Earth—45,935,684 cubic yards, at 25c --_______
Earth—1,769,739 cubic yards, at 200--_________
Rock—312,307 cubic yards, at 75c --__________

Total
15 per cent contingency-----------------------

Structures—
East Mesa Canal, No. 1 Turnout______________
Drop and Check-----------------------------
26 miles telephone line-----------------------

Total ---
15 per cent contingency----------------------

Mesa Canal No. 1 Sta. 1525 to Mesa Canal No. 2 Sta.
1915: -
Excavation—

Earth—2,344,556 cubic yards, at 180___________
15 per cent contingency----------------------

Structures— -
24 feet Drop Sta. 1740–-----------------------
Turnout for Mesa Canal No. 2––––––––––––––––
5 miles telephone line------------------------

Total
15 per cent contingency----------------------

Total ---------------------------------------

Mesa Canal No. 2 Sta. 1915 to end :
Excavation—

Earth—6,836,400 cubic yards, at 186___________

15 per cent contingency---------------------

Structures—
47-foot Drop Sta. 2004------------------------
Turnout_
Check__
Drop---

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