TABLE NO. 13.-Hydrology of Chagres River, dry season, 1917.1 Day of month, Apr. 26 and 27. Elevation (feet above mean sea level). Discharge (second-feet). Percentage of yield at Gatun. Length of records (years) Compared with station average, same seasons, per cent below. 1 Dry-season months are January, February, March, and April. 2 Compared with total yield. TABLE NO. 14.-Monthly discharge, Chagres River, Alhajuela, 1916. 686 93.90 3,830 90. 72 268 51 16 49 Discharge in second-feet. Run-off (depth in inches on Maximum. Minimum. Mean. 2,400 924 2,968 709 2,074 548 TABLE NO. 16.—Principal freshets of year 1916, and dry season 1917. TABLE NO. 17.-Monthly maximum, minimum, and mean elevations for Gatun Lake, Miraflores Lake, and Chagres River, 1916. January. 86.75 86.44 86.59 86.76 86.50 86.25 86.37 86.52 86.85 85.90 86.37 86.76 86.49 86.63 86.50 86.30 86.41 86.52 86.09 86.33 86.55 86.07 86.36 86.54 86.14 86.37 86.25 85.91 86.06 86.26 85.91 86.05 86.26 85.95 86.07 86.51 85.90 86.26 86.49 85.93 86.22 86.51 85.94 86.25 86.56 86.29 86.41 86.52 86.23 86.39 86.67 86.31 86.44 86.57 86.24 86.40 86.55 86.20 86.39 86.56 86.31 86.43 86.84 86.25 86.41 86.84 86.22 86.39 86.89 86.27 86.45 86.49 86.23 86.35 86.46 86.21 86.34 86.48 86.29 86.38 86.59 86.26 86.37 86.57 86.20 86.33 86.67 86.22 86.38 86.85 86.25 86.39 86.80 86.20 86.37 87.11 86.26 86.41 86.68 86.29 86.48 86.70 86.19 86.44 86.72 86.29 86.50 86.84 85.91 86.36 87.11 85.94 86.39 86.45 86.62 86.28 86.40 86.80 86.79 86.53 86.66 86.53 86.34 86.44 86.55 86.17 86.40 86.28 86.42 86.86 86.26 86.41 86.51 86.73 86.29 86.51 86.40 86.88 85.93 86.41 TABLE NO. 17.-Monthly maximum, minimum, and mean elevations for Gatun Lake, Miraflores Lake, and Chagres River, 1916—Continued. The section of surveys has attended to all Panama Railroad land and lot work and has continued its work of the care and maintenance of the established Canal Zone boundary monuments, triangulation stations, and bench marks; also the installation of new monuments, triangulation stations, and bench marks as required. This section has made surveys and prepared maps for other divisions and for the Joint Land Commission, and has continued its studies of the various features of the canal under observation. The details of the work accomplished by this section are covered in the report of the assistant engineer which follows: Colon monuments.-Surveys were made and 19 block monuments were set. An iron fishplate monument was set in Manz. 2, Folks River. Strangers Club lease.-A survey was made of the vacant ground between Second and Third Streets and Bottle Alley and the Panama Railroad. The quarter of the track lying adjacent to Second Street was staked out for lease to the Strangers Club, and a map was prepared on a scale of 1 to 600, showing location, dimensions, and area. Canteens. A survey was made and the restricted area line, 25 meters from the Zone line, was established by 16 monuments. Sketches were made showing the locations of the canteens. Cristobal. A survey was made of the block to the east of the Italian Steamship Company's lot, and a map made up on a scale of 1 inch to 20 feet for fitting in a lot 48 by 87 feet for the United Fruit Company. A lot was staked out on Roosevelt Avenue for the French Steamship Line and its location and area shown on plan No. 3517. The area of lot No. 11, Roosevelt Avenue, was determined in square feet and square meters. Folks River.-A map was prepared showing the location and area of lot No. 13, Manz. 2. A replot was made of lots 1, 2, 3, and 31, Manz. 1, and a map prepared showing the new layout with areas. Las Esplanadas, Panama.—The property line through the alley of section B was staked out for the municipal engineering department on account of construction work; the property line on section H was staked out on account of construction work on adjacent private property. A survey was made of section A for the new dimensions of lots 12-19-bis, inclusive, on account of a 16-foot roadway at the rear. Lots 16, 17, and 18 were consolidated into two lots and the map revised accordingly. Three bundary monuments were set in section B. Balboa.-A lot was staked out for the International Petroleum Company, and its location was shown on blue-print map, file No. 5048-1. Panama yard.-Lot No. 30 was staked out in Panama yard, and its location, with dimensions and area, shown on a map. GATUN DAM. Settlement hubs.-Readings were taken on the settlement hubs once a month, showing the normal settlement throughout the year. Bench marks D and L2.-The settlement of bench mark D for the year was 0.255 foot, while that of Le was 0.005 foot. Both are in the east valley, D being opposite the upper gates and near the bed of the Old East Diversion, while L is about 1,000 feet from the center gate of the spillway in a line toward the mouth of the French Canal, and is over original high ground of about 40 feet elevation. Soundings.—Ranges were established and soundings taken to the west of the south approach wall and over the old channel of the East Diversion. The east axis was rerun for the movement of the axis hubs toward the lake. The results were plotted onto map file No. 6031-1. Fill.-Grade stakes were set for a fill on the east valley, south toe. Hydroelectric plant.-The elevations of the old bench marks were checked and new ones established for use in the turbine tests. Mindi.-A profile was taken over Mindi levee, showing normal settlement. South approach wall.-Elevations were taken over the south approach wall twice each month, showing a maximum settlement of 0.233 foot for points 4 and 6, a minimum settlement of 0.046 foot at point No. 1 near the break, and an average settlement of 0.181 foot. Four new points were established, two at the break and two at the end, and the two old points, E and W, in the pits at the end of the wall were abandoned. Grades were given on 350 feet of rack track over the break for leveling off the wall. Cano Saddle.-Levels were run over Cano Saddle twice during the year, showing normal settlement. BENCH MARKS. Repairs. The following precise level bench marks were cleared and repaired: 9A, 10A, 11A, 13A, 14A, 15A, 16A, 17A, P.R.R.B.M.634+50, 7A, 39A, 32, 33, 34, 35, 37, 38, 38A, 43, 43A, 44, 44A. Transfers.-Precise level bench marks were transferred as follows: P.B.M.39 (Pedro Miguel), account of building construction; P.B.M.45A (Sosa), account of near-by construction work. Tide gauge, Colon.-The Colon tide gauge bench mark was checked up, and found to be O.K. Venado Island.-A permanent bench mark was established on Venado Island by the method of simultaneous high tide readings on the island and at Balboa. PRECISE TRIANGULATION. Slide commission.-The angles between the stations on Gold, Zion, and Contractors Hills were read in May and October, 1916, and in April, 1917, showing no movement. Stations along Panama Railroad.-Ten triangulation stations were established along the Panama Railroad as follows: 1, Balboa station; 2, P.B.M.43A at Corozal; 3, tunnel; 4, Pedro Miguel; 5, New Culebra; 6, bridge; 7, T 29-03, opposite Old Gorgona; 8, T 27-13, opposite Old Caimito; 9, New Frijoles; 10, Monte Lirio. The elevations were determined and descriptions written. Other new stations.-The following additional new stations were established: 1, Colon wireless (east one of the new towers); 2, Farfan; 3, Groundhog (2 and 3 are Old Pacific Division stations); 4, Amador; 5, Buena Vista; 6, Buzzard; 7, Calle Trece; 8, Chorillo; 9, Cocoa Grove; 10, harbor; 11, hospital; 12, market; 13, Pta. Paitilla S.; 14, sea wall; 15, Shine; 16, Pena Prieta; 17, Tivoli (16 and 17 are three pointers). Elevations have been determined for all except Farfan, Groundhog, and Pta. Paitilla S. Repairs. Sixty-seven Zone triangulation stations were cleared and repaired, and trochas opened up to sight stations. The clearing amounted to 92.7 acres. West Bas Obispo.-The geodetic coordinates of West Bas Obispo were found to be in error as originally reported, and were accordingly corrected. New Culebra.-The monument for triangulation station, New Culebra, was referenced out on account of stable construction by the supply department. Sosa High. The elevation of triangulation station, Sosa High, was found to be 370.06 feet by a closed circuit of Y levels. CANAL ZONE BOUNDARY LINES. Panama.-Monument A at Punta Mala was referenced out on account of road construction to Gabilan Island. Colon. The proposed new lines of the boundary between the Canal Zone and the city of Colon were traversed, the coordinates of the angle points determined, map prepared, and a description written up by metes and bounds. Monument No. 8 was set. 100-foot contour, Gatun Lake. The final field sheet data were transferred to the office copy, making two complete sets of blue prints, showing the 100-foot contour monuments. |