APPENDIX A.

REPORT OF THE ENGINEER OF MAINTENANCE.

THE PANAMA CANAL,

OFFICE OF THE ENGINEER OF MAINTENANCE,

Balboa Heights, Canal Zone, July 20, 1917.

SIR: I have the honor to submit the following report of work done under the jurisdiction of this office during the fiscal year ended June 30, 1917:

ORGANIZATION.

The duties of the engineer of maintenance have remained as in the past, excepting that on July 1, 1916, the construction of fortification work was transferred to the district engineer officer, United States Army; on December 1, 1916, the office of the engineer of docks was transferred from the Panama Railroad Company to this office; and on February 9, 1917, the office of the resident engineer, building division, was transferred to this office from the department of operation and maintenance.

The office was under your charge, with the undersigned as assistant to the engineer of maintenance, until January 11, 1917, upon which date the undersigned was appointed engineer of maintenance upon your vacating that office upon your appointment as Governor.

The various divisions and sections have been in charge of the following personnel:

Electrical division.-Maj. William H. Rose, United States Army, continued as electrical engineer until his relief from duty with The Panama Canal on June 1, 1917, when Maj. Theodore H. Dillon, United States Army, was appointed electrical engineer.

Building division. Mr. Hartley Rowe, resident engineer, has been in charge of the building division since February 9, 1917, when he succeeded Mr. George M. Wells.

Locks divisions.-The Atlantic locks continued under the direct charge of Capt. T. H. Dillon, United States Army, until March 5, 1917, when Capt. E. J. Atkisson, United States Army, was appointed superintendent. Mr. E. D. Stillwell was appointed superintendent effective April 15, 1917, vice Capt. Atkisson, relieved from duty with The Panama Canal. Mr. W. R. Holloway was appointed superintendent of the Pacific locks, effective August 16, 1916, vice Mr. R. H. Whitehead, resigned.

Municipal division. Mr. D. E. Wright, municipal engineer, continued in charge of this division.

Terminal construction. Mr. T. B. Monniche, engineer of docks, has been in charge of the Atlantic dock construction (excepting the Cristobal coaling plant) throughout the year. Mr. F. H. Cooke, designing engineer, was in charge of the Cristobal dock construction and all Pacific dock construction work until his relief from duty with the canal, after which date Mr. Bernard Duchscher, assistant engineer, had charge of all coaling plant inspection work and Mr. A. R. Brown, assistant engineer, had charge of other construction work at

the Pacific terminals. Since April 14, 1917, Mr. A. R. Brown has also had charge of the work of completion of coaling plants.

Section of meteorology and hydrography.—Mr. F. D. Willson, chief hydrographer, continued in charge of this section.

Section of office engineer.-Mr. C. J. Embree, office engineer, continued in charge of this section.

Section of surveys.-Mr. O. E. Malsbury, assistant engineer, continued in charge of this section.

LOCK OPERATION AND MAINTENANCE.

LOCKAGES.

The following table gives the total commercial and noncommercial lockages of the year:

Complete data as to Gatun Lake hydrography are given hereinafter, but for your information the following data have been compiled for the past fiscal year.

During the exceptionally dry season of last winter the lake was drawn from plus 86.70 feet on January 2 to a low point of plus 83.14 on April 27. During this period there were used for power development 12.910.57 million cubic feet of water, an amount which is not greatly below the storage capacity of the lake between these two levels. In other words, if the hydroelectric station had been withdrawn from service throughout the dry season, and if no spilling had been enforced, Gatun Lake would have passed through the dry season with a loss of level of only 0.7 foot, although supplying water for an average of 166 through lockages per month.

The new hydroelectric station when developed to its ultimate capacity will call for about 150 per cent more water than the existing station, a monthly consumption of about 7,700 million cubic feet, as against 3,080 million cubic feet at present. A study has been made as to the effect this enlargement of the station will have on the lake. storage in an exceptionally dry season, and the following results may be briefly stated:

Between the levels of +87 (which may be regarded as the practicable maximum at which the lake may be held during the month preceding the dry season drop in elevation) and +80 (42.67 feet over upper miter sills and 40 feet draft through the lake channels) there is storage capacity for 31,890 million cubic feet of water. Assuming inflow and all losses, except those for lockage and power, the same as during the last dry season, the study shows that without any use of water for power, the lake would have provided sufficient water for an average of 40 through lockages per day.

There is no doubt as to the ability of the lake to enter on the dry season at its maximum level, even with this increased use of water for power purposes, throughout the wet season, and with an increased use of water for lockage up to the capacity of the canal for traffic. The increase in the water consumption by the hydroelectric station will simply utilize some portion of the water supply which would otherwise be wasted over Gatun spillway, and the plant may be operated at full capacity during at least eight months of the year, and at partial capacity during the dry season, depending upon the amount of traffic passing through the canal. During successive dry seasons it will be necessary to closely observe the growth in traffic and the accompanying increase in demand for water for lockage purposes. As the locks demand an increasing amount of water, the power output of the hydroelectric station may be decreased, supplying the deficiency in power from the steam station at Miraflores. This arrangement of using Miraflores steam plant as a reserve for power is preferable to any plan involving an additional hydroelectric-power site, as its installation would involve a heavy expense and heavy maintenance charges on a long transmission line through the jungle, without eliminating the auxiliary steam plant, which is necessary at all times as an emergency reserve.

GATUN DAM.

Monthly surveys of Gatun dam disclosed the fact that a slight settlement had been taking place in the dam west of the locks. When work was started on the hydroelectric-station penstock excavation, it was decided to take advantage of the opportunity and use the earth

for bringing this section of the dam back to grade, and 15,000 cubic yards of earth were emplaced on the dam, to an average depth of about 2 feet 9 inches. The remainder of the earth and rock removed, 25,700 cubic yards, was dumped on the Mindi levee.

REGULATING VALVES.

The regulating valves were installed complete upon the following dates:

Arrangements are being made to install new fender timbers at lower Miraflores locks. The upper wooden buffers are in fair condition, but the lower set which are immersed at high tide are rotting badly and have to be replaced.

TOWING LOCOMOTIVES.

During the year the mechanical division completed the construction of four towing locomotives for the locks, these machines being the same as those now in service except that the cabs have been increased in height to allow the operators a better view of the vessels being towed.

BACKFILL AND GRADING.

At Miraflores locks the filling on the lower level of the east bank and the slope between the lower and upper levels was completed during July, 1916. The grading of the lower west side backfill was completed in June, 1917.