USA > California > History of California, Volume V > Part 33
Note: The text from this book was generated using artificial intelligence so there may be some errors. The full pages can be found on Archive.org (link on the Part 1 page).
Part 1 | Part 2 | Part 3 | Part 4 | Part 5 | Part 6 | Part 7 | Part 8 | Part 9 | Part 10 | Part 11 | Part 12 | Part 13 | Part 14 | Part 15 | Part 16 | Part 17 | Part 18 | Part 19 | Part 20 | Part 21 | Part 22 | Part 23 | Part 24 | Part 25 | Part 26 | Part 27 | Part 28 | Part 29 | Part 30 | Part 31 | Part 32 | Part 33 | Part 34 | Part 35 | Part 36 | Part 37 | Part 38 | Part 39
532
HISTORY OF CALIFORNIA
8.1 miles long. Including the channel dredged from the shore to deep water in the Bay of Panama, the length was to be 46.6 miles. All locks were to have twin chambers, giving two routes to vessels. The chambers were to be 738 feet long and 82 feet wide. The bottom width of the channel was fixed at 164 feet in Lake Bohio and the Bay of Panama, 118.1 feet in the summit level, and 98.4 feet elsewhere.
It was the hope of the new company to omit the summit level, described above, making the Lake Bohio level continuous to Pedro Miguel, thus saving two locks on each slope, but making the cut through the ridge correspondingly deeper. This was to be done in case experience in the early work on the first plan should demonstrate the feasibility of the change.
The work of the New French Company was confined principally to excavation in the summit level. Under its control about ten million cubic yards of material were removed, and data of great value were collected, bearing upon the regimen of the Chagres River and the topographic and hydrographic characteristics of the region bordering the canal. The first French Canal Company expended about $254,000,000, of which about $152,000,000 were spent on the isthmus. The second French Company expended in all about $11,000,000, principally on the isthmus.
AMERICAN CONTROL
By act of March 3, 1899, the Congress of the United States empowered the President to make full and com- plete investigation of the Isthmus of Panama with a view to the construction of a canal. To accomplish
533
THE PANAMA CANAL
this, he appointed a commission of nine members, headed by Rear Admiral J. G. Walker, U. S. N., which reported in November, 1901, in favor of the Nicaragua route, having in view the fact that the New Panama Canal Company demanded what was regarded as an excessive price for its rights and property. The com- pany, after further negotiation, reduced its demands from $109,000,000 to $40,000,000. In consequence of this reduction, which made the estimated cost via the Panama route less than that via the Nicaragua route, the commission in January, 1902, submitted a supple- mentary report favoring the Panama route. Congress then passed the "Spooner Act," of June 28, 1902, empowering the President to proceed with the con- struction of a canal by the Panama route, provided that the New Panama Canal Company would sell its rights and property for a sum not exceeding $40,000,000 and that suitable arrangements could be made with the Colombian government for the control of the neces- sary right of way. Failing fulfilment of these condi- tions, the Nicaraguan route was to be adopted. The law required the canal to be of sufficient capacity and depth to "afford convenient passage for vessels of the largest tonnage and greatest draft now in use, and such as may be reasonably expected."
The condition as to the acquisition of the French company's property was readily fulfilled. A treaty known as the Hay-Herran treaty, empowering the United States to build the canal, was formulated after negotiations with Colombia. This treaty was thought to be satisfactory to both governments, and was ratified by the United States senate, but was finally rejected by
534
HISTORY OF CALIFORNIA
the Colombian congress in 1903. The province of Panama thereupon seceded from the Republic of Colombia, on November 3, 1903, and achieved its independence. The United States recognized the new government at once, and negotiated a treaty by which it agreed to pay Panama $10,000,000 outright and an annual sum of $250,000 beginning nine years from the date of the treaty, acquiring in return the right to build the canal, and the exclusive sovereignty over a strip of land across the isthmus, ten miles wide, five miles on each side of the axis of the canal. The cities of Panama and Colon, although geographically within the Canal Zone, are reserved as Panamanian territory.
There is no doubt that the United States received fair value for the sum of $40,000,000 which it paid the New Panama Canal Company for its rights and property. The Panama Railroad alone had cost the French $18,000,000, although the par value of the stock was only $7,000,000. The machinery and buildings which the United States acquired were worth a large sum, the land holdings were valuable, and the work done by the French in places where it proved useful to the Americans, was also an asset of great importance. A careful appraisal made by a committee in 1911 placed the total value of the property and rights acquired from the French Company at $42,799,826. It appears, therefore, that the bargain was a fair one.
PROPOSED SEA-LEVEL PLAN
Under authority of the Spooner Act a commission of seven members, with Admiral Walker as chairman, was appointed in 1904 to prosecute the work. The
535
THE PANAMA CANAL
type of canal to be built was decided after discussion of the subject by an international board of consulting engineers appointed by the president of the United States on June 24, 1905. This board consisted of eight members from the United States and five appointed upon nomination of Great Britain, France, Germany, and the Netherlands, one of the foreign members being also connected as consulting engineer with the Suez Canal. Seven of the twelve, of whom two only were Americans, reported in favor of a sea-level canal, with bottom width of 150 feet in earth cutting and 200 feet through rock, and with a low-water depth of 40 feet, ex- cept in Panama Bay where it was to be 35 feet. The canal was to follow a line consisting practically of a series of curves, and was to have a tide lock near the Pacific end, where the extreme tidal oscillation is about 20 feet. At the Atlantic end, where the tidal oscilla- tion is only about 2 feet, no lock was deemed necessary. The Chagres River was to be regulated at Gamboa by a dam with devices by which the water of the impounded reservoir could be admitted to the canal at a rate not to exceed 15,000 cubic feet per second. This amount is larger than the mean discharge of the river in the wet season. Floods of greater volume were to be absorbed temporarily by the reservoir, and admitted gradually through the regulating gates. The main tributaries were to be diverted from the canal, but smaller ones were to be admitted, a possible current of 2.6 feet per second being contemplated. The cost was estimated at $247,000,000 and the time of construction at from 12 to 13 years.
536
HISTORY OF CALIFORNIA
ADOPTED PLAN (SEE PLATE I)
The minority of the consulting board, consisting of five members, all American engineers, favored the con- struction of a lock canal. The plan as formulated and finally adopted placed the summit level at 85 feet above mean sea level. This level is formed and maintained by a dam across the Chagres River at Gatun. The total length of the canal is 50 statute miles. From deep water in Limon Bay to Gatun, a distance of 7.7 miles, the canal lies at sea level with width of 500 feet and depth of 40 feet at low water. The rise from sea level to the surface of Gatun Lake is accomplished by three locks in flight. From Gatun to Gamboa, a dis- tance of 23.3 miles, the channel lies in Gatun Lake, with a width varying from 1,000 to 500 feet. From Gamboa to Pedro Miguel, 8.4 miles, the channel, with surface still at the summit level of 85 feet above mean tide, passes through the Culebra Cut, and was origi- nally planned with a bottom width of 300 feet for 3.4 miles, and 200 feet for the rest of the way. This latter width was increased during construction to 300 feet. At Pedro Miguel a lock is placed to overcome the differ- ence of 301 feet between the level in the Culebra Cut and the intermediate level next below, which is 2.2 miles long and 543 feet above mean tide, and is formed by a lake impounded by a dam at Miraflores. A flight of two locks in this dam allows vessels to pass into the sea-level stretch below, which is 8.4 miles long. In the intermediate level below Pedro Miguel and in the sea- level stretch extending to deep water in Panama Bay
PLHala Remo Cafeta, AS
añoPrincipal
L.H.
ELH.
COLON
CRISTOBA
3Bay off Manzanillo
LIMO
Vierajal
RAY
Mt.Hopen/
Co(Ruinsk
ag es
BBRAZOS
RIO
ACH
Mindi
Çalı
GATUN LOCKS AND DAM
GATUN
Kontokirill
PRange Ligtos Lio nHills
PANAMA
CANAL
.OF PANAMA ZONE
V.
Frijoles
Pihiva
PaloGrande ON Road
Gamboa Bridge
CerroGrande Matarlifn
Bast bispo Hassanbi CampElliet RIO
Cruces
Campotis. Immette
Empire .S
Gold H
Hebya
CAMACHO RES Y
. RIO GRANDE IRES PEDRO MIGUEL LOCKS
- Miraflores L.
MIRAFLORES LOCKS
;Corozal
Coroli L
Pt.Paitilla
RC Ancona
Punamallar bor
Ar
jan
RALBO.
PANAM
BREAKWATER
IR Velazquez PaloSeco ; Culebr
Napsl.
R Aguacate
.(Leper Ch /1 Chang
0
vrro de Cabra
SPt.Bruje
&Venado!
&Cocc
Pt.Vacamonte
Rio Malerique
Bohi
RL
REPUBLIC
Patos
Rio Più0
PLATE 1
ES
/ REPUBLIC
U!
Gor
CAN
(1000 Ft )
ONE
PANAMA !
TINENTAL
Margarita 1.
FOTO BREAKWATER
THAGRES
537
THE PANAMA CANAL
the width is 500 feet. The least low-water depth is 412/3 feet in fresh water and 40 feet in salt water, except in the Pacific sea-level stretch where it is 35 feet.
The dam below Pedro Miguel was originally planned to close the valley of the Rio Grande near its mouth in Panama Bay. Because of difficulties which developed after construction began, and because of military considerations, it was later moved inland to Miraflores.
The canal alignment consists of a series of tangents widened at the points where the direction changes. It has 22 angles with a total curvature of 600° 51', of which 281º 10' are measured to the right, going south.
The minority members of the consulting board estimated the cost of the plan at $139,705,200 and the time of construction at nine years.
The report of the minority was indorsed favorably by the Isthmian Canal Commission excepting one mem- ber, by the chief engineer of the commission, by the Secretary of War, and by the President. Construction along the lines recommended therein was authorized by Congress in the act of June 26, 1906.
The decision to build a lock canal instead of a sea- level channel, although based principally upon the initial estimate and the greater convenience to naviga- tion of the lock canal proposed, justified itself on other grounds during the period of construction. Difficulty much greater than had been anticipated was experi- enced in the course of the dry excavation, because of earth and rock movements or slides. Even in the shallower cuts of the lock-level plan, the increase in excavation due to these movements had reached the total of 22,870,000 cubic yards on the first of July, 1913,
538
HISTORY OF CALIFORNIA
and there were at that time several formidable slides still moving. The slides increased in volume and fre- quency as the cutting grew deeper from season to season, and the amount of material removed because of them increased even more rapidly. In the period from 1904 to 1909 the material removed from slides was 7.87 per cent of the total removed in the Central Division. This percentage shows a steady gain from year to year until, in the year ending June 30, 1913, out of a total of 12,773,338 cubic yards of material removed from the Central Division, 5,889,200 cubic yards, or 46.67 per cent, were due to slides, and the material thus added was more than usually difficult to remove. One can only conjecture what the result of such earth move- ments would have been, had the cut through the summit level been 85 feet deeper, as for a sea-level canal of equal navigable depth; but no one can doubt that the addition in material to be removed would have been far greater than was experienced in the plan actually followed, and that the duration of the work would have been more than correspondingly increased.
The difficulties in cutting a sea-level channel through the marshes which now lie at the bottom of Gatun Lake cannot be so directly estimated by experience, since the plan adopted wisely avoided such excavation altogether; but they would certainly have been serious. On the whole, it is probable that any nation, however rich, which should have undertaken the construction of a sea-level canal, would have become so discouraged in the progress as either to abandon the work, or to change to a lock-level project, as did the French.
539
THE PANAMA CANAL
PREPARATORY WORK
The first three years after the appointment of the commission under the Spooner Act were devoted largely to the preparatory work of organization, sanitation, and equipment. Comparatively little was done in the way of actual excavation until the year 1907. During the time of preparation the commission, as a body, did not reside on the isthmus, but made periodic visits there and administered the work from an office in Washington. The personnel of the commission was changed from time to time, the chairmen before April 1, 1907, being successively Rear Admiral John G. Walker, U. S. N., retired, Theodore P. Shonts, and John F. Stevens. The chief engineers were successively John F. Wallace and John F. Stevens. By executive order of March 4, 1907, the president of the United States appointed Lieutenant-Colonel George W. Goethals, Corps of Engineers, U. S. A., a member of the commission, and named him chairman April 1, 1907, upon which date he was also appointed chief engineer. At the same time the personnel of the commission was changed, and the members were all required to live on the isthmus in close touch with the work. This plan was followed until the completion of the canal.
The main constructive features were the excavation, the lock and dam construction, and the harbor and terminal work.
EXCAVATION
The excavation was divided between dredging and dry excavation. Of the entire amount removed by the French about 29,908,000 cubic yards were useful in
540
HISTORY OF CALIFORNIA
the plan adopted by the Americans. In addition, the work required the removal of about 232,000,000 cubic yards, of which about 129,000,000 cubic yards were dry excavation and the remainder dredging. The progress made by years is given in the following table:
May 4 to December 31, 1904 243,472
January I to December 31, 1905
1,799,227
January I to December 31, 1906 4,948,497
January I to December 31, 1907 15,765,290
January I to December 31, 1908 37,116,735
January I to December 31, 1909 35,096,166
January I to December 31, 1910 31,437,677
January I to December 31, 19II 31,603,899
January I to December 31, 1912 30,269,349
January I to October 1, 1913 22,767,886
Total 211,048,198
The highest monthly record made at any time was in March, 1909, when a total amount of 3,889,327 cubic yards was removed from the canal prism, of which 1,527,434 cubic yards were dredged and the remainder taken out in the dry.
The equipment for dry excavation consisted of IOI steam shovels, of which 45 had 5 cubic yard dippers, 43 had 212 cubic yard dippers and the remainder were smaller. The record for a single shovel was 4,823 cubic yards loaded in one day of eight hours. In the month of March, 1911, the average daily performance of 50.6 shovels was 1,434.6 cubic yards each in eight hours under steam. To remove the earth handled by the shovels, 1,760 flat cars, unloaded by plows, and 1,803 side dump cars, with an adequate supply of locomotives and auxiliary rolling stock, were provided.
541
THE PANAMA CANAL
For the wet excavation there were available in all-
7 small ladder dredges, old French
I large ladder dredge, new
4 pipe line suction dredges, new
3 pipe line suction dredges, old
3 5-yard dipper dredges, new
2 sea-going suction dredges, new
I clamshell dredge
2 15-yard dipper dredges, received in 1914.
The floating equipment included the necessary tugs, scows, drill barges, and one Lobnitz rock crusher.
The end of the dry excavation was practically reached in September, 1913. Up to that time, the Culebra Cut had been excavated in the dry, the trench being drained by gravity both to north and south, and being closed at the north end by a dike at Gamboa, which protected it, first, from the floods of the Chagres, and, later, from the rising water of Gatun Lake. The drainage flowing to the north was pumped through the Gamboa dike into the river outside. On September 10, 1913, all the excavation in the Cut which it was practicable to do by dry methods had been finished, the material remaining to be removed being principally that due to slides, which could be handled most advantageously after the admission of water to the prism should provide some support to the banks and partially check the movement of the lower strata. After removal of equipment from the Cut, the pump valves at Gamboa were opened on October 5th, and water gradually admitted, and on October 10, 1913, the Gamboa dike was blown up. The water in the Cut rose at once to the level of the lake outside, and the remaining excavation was accomplished by dredging.
542
HISTORY OF CALIFORNIA
LOCK AND DAM CONSTRUCTION
The work of construction of the locks and dams was localized at three places, Gatun, Pedro Miguel, and Miraflores. At Gatun a dam closes the Chagres Valley, making Lake Gatun, and having as one of its abutments a flight of three locks to raise vessels from sea to lake level, a distance normally of 85 feet. The dam is of earth and rock, the crest being 105 feet above sea level, or 20 feet above the normal level of the water retained. The ground upon which it is built was in part low and soft. It was necessary, therefore, to make the base very wide and the slopes gentle, in order to avoid overloading the foundation. The dam is about 7,800 feet long, measured on the crest, and about 2,500 feet wide at the base of the highest portion. It contains about 23,000,000 cubic yards, of which about 12,000,000 cubic yards are dry material and the re- mainder hydraulic fill. Two rows of hard rock were first deposited along the site of the dam, 1,200 feet apart, and parallel to the axis. The natural surface between these rows of rock was cleared and a bonding trench dug. A mixture of sand and clay, excavated by hydraulic dredges from borrow-pits above and below the dam was then pumped between the rows of hard rock, and these were at the same time extended upward on the selected slope by dumping dry material toward the axis of the dam. The base was also widened out- ward in the same way (see plate 2).
A spillway is built near the middle of the length of the dam, in the rock of a natural hill. It is arched in plan, and consists of a concrete dam with crest 16 feet
PLATE ?
CHAGRES
R
)
WESI
DIVERSION
--
FRENCH
-
-
FAST
DIVERSION
Panama
R
Old Line
R
R
=
CANAL
Panama
ATUM
STA
LOCK
5
Srole
0
5.00
250"
900GD **
GATUN
DAM
CHAGRES
SPILLWAY.
543
THE PANAMA CANAL
below normal lake level, surmounted by fourteen regu- lating gates, the tops of which are three feet above normal lake level, and which may be raised between piers 45 feet apart, as a window sash is raised between its jambs. When a regulating gate is raised the water flows out under the lower edge and over the crest of the concrete dam. With all the gates raised, the dis- charge with the lake level at +-87, or two feet above normal level, would be about 154,000 cubic feet per second, or more than the greatest discharge of the river at flood. Work on the dam began in July, 1907, and was finished six years later. The spillway was closed on June 27, 1913, and the lake was allowed to rise until it reached full height.
Gatun Lake extends over an area of 164 square miles and has a watershed of 1,320 square miles. It covers the line of the canal from Gatun to Pedro Miguel, a distance of 32 miles. At Pedro Miguel the water is retained by an earth dam with crest 105 feet above mean tide, extending northward from the west wall of the lock and parallel to it, forming an artificial bank to the canal, which, with the lock, closes the old valley of the Rio Grande. The dam is 1,800 feet long and contains 696,000 cubic yards of material. It was built of dry fill and consists of a core of puddled clay retained by parallel toes or masses of rock and earth. A twin lock with single lift enables vessels to pass between the waters of the Culebra Cut at the Gatun Lake level of +-85 and those of the Miraflores Lake at level of +-543. The normal lift of the lock is therefore 30} feet.
544
HISTORY OF CALIFORNIA
Miraflores Lake, which has an area of 114 square miles, constitutes a level of the canal intermediate between Gatun Lake and the sea at Panama Bay. It is retained by Miraflores dam and lock. The dam with crest at elevation+70 extends southward from the head of the upper lock in a direction nearly parallel to the lock wall for about 2,400 feet to a hill opposite the foot of the lock flight, closing the valley of the Cocoli River, a tributary of the Rio Grande. The lock and spillway close the remainder of the old Rio Grande valley. The main dam is of earth and rock. It con- tains 2,370,000 cubic yards of material of which 661,000 are hydraulic fill.
The spillway is similar to that at Gatun, except that it has eight regulating gates instead of fourteen, and is straight in plan instead of curved. It is much larger than would be needed to regulate the small lake above it, and was designed to provide against the flow which would come from Gatun Lake if the gates in one of the Pedro Miguel locks should be carried away. A flight of two locks lowers vessels from Miraflores Lake to the sea level below. The lift varies with the tide from 643 feet to 442 feet. The sea-level stretch extends to deep water in the Pacific Ocean, eight miles below Miraflores locks.
The locks are similar at all the dams, there being a flight of three at Gatun, two at Miraflores, and one at Pedro Miguel. Plate 3 shows the upper lock of the Gatun flight. Each lock is double, having twin cham- bers separated from each other by a middle wall. Each chamber has useful dimensions of 1,000 feet in length and I10 feet in breadth, capable of taking in the largest
7
IC
LE
PLATE B
IF
F
'5
. .
545
THE PANAMA CANAL
ship now afloat, with some margin for growth. Inter- mediate gates divide the chamber into two locks 600 and 400 feet long, either of which may be used in order to save water. For reasons connected with the tidal oscillation, the lower Miraflores lock has no inter- mediate gates. The locks are filled and emptied through culverts in the base of each wall. These cul- verts, which have a cross sectional area of 254 square feet, the equivalent of a circle 18 feet in diameter, run the entire length of each lock wall, from the intake in the fore-bay to the outlet in the tail-bay. They communicate with the chamber by means of lateral culverts, at right angles to the main culverts, which run under the lock and open upwards through holes in the floor (see plates 3 and 4). The entrance to the side wall culverts is by three openings closed by gate valves. The middle wall culvert is also entered through three openings into the fore-bays on each side. At each lift the main culverts are closed by gate valves in pairs, each valve closing one-half of the culvert area. The side culverts have similar valves at the intermediate gates, permitting the lock chamber to be divided. At the head and foot of each lock there are two sets of main culvert valves, one of which can be used when the other is out of service for any reason. The gate valves are all of the "Stoney" type. The lateral culverts from the middle wall to the chamber on each side are controlled by individual cylindrical valves, in order that the water in the middle culvert may be sent into one or the other of the twin lock chambers at will.
The lock gates are of steel, cellular in construction, 7 feet deep, and ranging in height from 47 to 82 feet.
546
HISTORY OF CALIFORNIA
There are 92 gate leaves on the canal. They are hung by collar and pintle only, no rollers being used. The heaviest leaf weighs 730 tons and the lightest 390 tons of 2,000 pounds. If piled on top of each other, end to end, they would make a tower more than 1 14 miles high.
The most important of the gates are guarded by fender chains stretched across the lock near the water level, when in use, and lying in a groove of the lock floor, when not in use. The chains pay out against a hydraulic resistance when struck, and are capable of arresting a vessel weighing 10,000 tons and moving at 372 miles per hour, before the gate would be reached.
Above the upper guard gates of each lock is placed an emergency dam, for use in case, through an accident, the gates should be carried away and the water of the upper level allowed to flow through the lock. The dam, which can be turned like a pivot drawbridge, would then be swung across the lock, girders dropped from the lower chord to a bearing on a sill in the lock floor, and wickets of rectangular form lowered along the runway formed by the upstream flanges of the girders. These wickets are placed in horizontal tiers, thus progressively closing the waterway in the face of the current and enabling the gates below to be closed or repaired.
Need help finding more records? Try our genealogical records directory which has more than 1 million sources to help you more easily locate the available records.