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Chief Federal Canals in the United States Source (as of June, 1941): Chief of Engineers, U. S. Army. Canals in italics are ship canals
Project Dimensions (Min.)
Status Length Width Depth
(Miles) (Feet) (Feet)
Atlantic Intracoastal System
13.5 500 32 Inland Waterway, Md. & Del... Chesapeake Bay-Delaware River
(includes Chesapeake & Dela-
80 (a) 10 Inland Waterway....
Beaufort to Cape Fear River,
90 12 Intracoastal Waterway
Cape Fear River, N. C., to St.
90 12 Intracoastal Waterway Jacksonville to Miami, Fla, 1935
100 Intracoastal Waterway Miami to Florida Bay, Fla
Apalachicola River to Mobile Bay 1938 217,4 100 9
9 Intracoastal Waterway
New Orleans-Corpus Christi,
125 30 Houston Ship Channel.
94% 57.3 200 34 Great Lakes System Kruerndw llateru.
300 25 Sturgeon Bay-Lake Michigan Ship (anal
130 22 St. Mary's Falls Canal, Vorth.
80 24.5 St. Mary's Falls ('anal, South
1.56 100 18 St. Mary's Riret. Including St. Mary's Falls Canal 1937 63
1500 (0) 20.6 (0)
300 (d) 25 (d) Detroit Rinet.. Incl. Channels in Lake St. Clair 99% 31
9 Illinois Waterway (8 locks and dams)
81% 325.6 300
9 Ohio River (46 locks and dams)
125 7-9 Allegheny River, Pa.. Pittsburgh to East Brady, Pa. 198 %
4 Kanawha River, W. Va. (4 dams Kanawha Falls, W. Va, to Point and 8 locks).. Pleasant. W. Vå.
95% (h) 90.6
9 Columbia River, Oregon. Mouth to Dalles, Oregon.. 158 (1) 190
27 (a) Width through Dismal Swamp Section, 50 feet.
(b) Route via Harvey Canal. Alternate route through Plaquemine Lock, 639.5 miles. (c) Upstream Channel
(d) Downstream Channel. (e) Lock width for Locks 2 to 26, incl.; Lock No. 1 has chamber width of 56 feet.
in Channel open to navigation. Construction under way to obtain full project dimensions. (8) Ninefoot depth available. Locks and dams completed but not all auxiliary works.
(h) Project depth available, Work remaining acquisition of fiowage easements.
(i) Project depths available except between Vancouver and Bonneville. This reach now under construction
(1) Columbia River, Mouth to Bonneville, 300-500 ft. wide. Bonneville to Dalles, Ore., ample width in open lake.
Completion status of Okeechobee, Houston Ship, Keweenaw, Warrior River, and Columbia River is as of Jan., 1941; the others are as of June, 1940.
Cargo Traffic on Chief American Canals
Source: Board of Engineers for Rivers and Harbors, U. S. War Department
Duluth-Superior IN. Y.State
Dollars Tons 82,514,457 1,021.528.978 71,290,304 882,263,141 40,494,672 368,802.154 1.858,114 1920.. 80,410,082 1,135,390,357 79,282,496 1,119,774.214 46,808,613 552,900.033 1,421,434 1925. 90,400,529 1,233,967,221 81.575,108 1,117.817,292 51,334.641 471,675,972 2,344,013 1930.. 94,155,889 982,987,481 72.897,752 760,968.185 45,726,085 347,271,631 3,605,457 1935.
75,779,230 1,079,854,740 48,293,308 658.004,883 29,184,768 270,865.557 4,489,172 1936. 96,777,290 1,112,938,835 69,528,600 799,786,656 44.516.827 356,021.355 5,014,206 1937. 113.836.956 22.214.171.124 87,633,699 925,644,409 57,138,579 446,071.717 5.010.464 1938 61,826,844 868,364,123 40,042,739 581,521,592 23,060.630 272,066,115 4,709,488 1949 91.643.043
38,048, 406 343.062,814 4,689,037 1940 111,340.567
54,147,695 407,484,967 4.768, 160 Value figures for the Detroit River and Sault Ste. Marie have not been compiled since 1938. The Duluth-Superior valuations for the commodities, the U. S. Engineers Office states, were largely derived from daily or weekly prices current and from quotations by principal shippers, owners, and carriers, and represent valuations at Lake Superior ports. The valuations of all Canadian and foreign commodities were obtained from the U. S. Customs Service.
Description of the Panama Canal
Source: Governor of the Canal Zone The Panama Canal is a lock and lake type canal, Lake. Madden Lake covers approximately 22 traversing the Isthmus of Panama between the square mlles at maximum level, 260 feet above sea Atlantic Ocean (Caribbean Sea) and the Pacific level, providing reserve storage of 22 billion cubic Ocean (Gulf of Panama) with headquarters in
feet of water for use in maintaining the level of
Gatun Lake during dry seasons. Balboa Heights, Canal Zone. It is approximately go
Gatun Lake covers approximately 165 square North latitude and 79° West longitude, almost due
miles at normal level. It is impounded behind south of Pittsburgh, Pa., and Charleston, S. C.
Gatun Dam, built of rock and earth across the There is no difference between the average mean Chagres River at Gatun, connecting the hills op level of the Pacific at Panama and the Atlantic either side with a low hill near the center of the at Colon. But at Colon there are small tides of i valley. foot and at Panama large tides of 10 feet above The Canal Zone is a strip of land extending five and below the average level.
miles on either side of the center line of the Canal On the Atlantic slope the Canal follows the former but excluding the cities of Colon, at the Atlantic valley of the Chagres River, on the Pacific, that of end. and Panama, at the Pacific, which remain the Rio Grande. Dams were built across these within Panama. It has by the census of 1940 a valleys to form lakes on which the ships are floated, population of 51,827. Work on special defense and connection between the two valleys, through projects and for building a third set of locks has the intervening divide, was made by excavating resulted in a considerable increase of civilians in Culebra Cut (officially named Gaillard Cut).
the past year. The summit elevation, i. e., the surface of Gatun The Zone was granted to the United States by Lake and of Gaillard Cut, which is an artificial arm the treaty with Panama of February 26, 1904. The of the lake, is normally 85 feet above sea level, and United States paid Panama $10,000,000 and $250,the bottom of the Cut was excavated to 40 feet 000 per year after the ninth year, and subsequently above sea level, giving normal depth of 45 feet. paid Colombia $25,000,000 under the treaty of 1922. The channel through Gatun Lake is 2334 miles The United States has acquired title to all of the long, and the Cut is 8 miles long.
land in the Canal Zone, reimbursing private The locks serve to raise ships from the sea to the owners, and no land is now available for private summit level, or to lower them to sea after they ownership. have crossed the Isthmus, On the Atlantic side American occupation of the Canal Zone began on the lift is made at Gatun Locks, which have 3 steps May 4, 1904, and the Canal was opened to traffic on or chambers, called lower, middle, and upper. On August 15, 1914. Traffic in the early years was the Pacific side, one step is made at Pedro Miguel hampered
by slides and reduced by war conditions, end
and the Canal was declared officially opened on at Miraflores Locks, about a mile to the south; July 12, 1920. The end of the fiscal year 1921 was between them is Miraflores Lake, with its surface adopted as the date the Canal could be considered normally 54 feet above sea level. Sections at sea completed, and the cost as of June 30, 1921, with level extend between the Atlantic Ocean and Gatun interest on the investment in earlier years comLocks. 623 miles, and between the Pacific and Mira- pounded annually at 3% was established by the flores Locks. 8 miles.
Bureau of Efficiency at $525,812.661. The line of the Canal is northwest-southeast, and The Canal Zone is a Government reservation adthe Pacific end is 27 miles east of the Atlantic end. ministered by the organization known as The
The Canal is 44.04 nautical miles or 50.72 statute Panama Canal, This is an independent organizamiles in length, at least 300 feet wide at the bottom tion in the Government service whose head is the of excavated channels, 110 feet wide in the lock Governor, directly under the President. AS a
chambers, which have a usable length of 1,000 feet. matter of executive arrangement, the Secretary of • Depth varies but is not less than 41 feet in sea level War represents the President in the administration sections or with surface of Gatun Lake.
of Canal Affairs. The Zone is fortified and occupied The Canal can handle any ship except the Nor- by a garrison in addition to the civilian employees mandie, the Queen Mary, and the Queen Elizabeth. of the canal and railroad. which are too large for the lock chambers.
The Army maintains air ports at France Field on A concrete dam across the Chagres River at the Atlantic side and Albrook Field on Balbos Alhajuela was completed in 1935, creating Madden 'Heights on the Pacific side.
Third Locks Project The Third Locks Project, providing for the construction of an additional set of locks located approximately parallel to, but at some distance from, the existing locks at Gatun, Pedro Miguel and Miraflores, and for the construction of the necessary by-pass channels connecting the new locks with the present Canal channel, together with such appurtenant facilities as may be deemed necessary, at a total cost not to exceed $277,000,000, was authorized by Act of Congress, approved August 11, 1939.
This legislation authorizing the construction of additional facilities in the Canal Zone was enacted for the purpose of more adequately providing for the defense of the Panama Canal and for increasing its capacity for the future needs of interoceanic shipping.
The locks of this new project are to have available dimensions of 140 feet by 1.200 feet, with a 45-foot salt water draft over the sills. Actual work on the new project started July 1, 1940.
Cargo Traffic on Chief Foreign Canals
Source: Official Reports of the Several Waterways
Panama Manchester Short Tons Short Tons Short Tons Net Reg. Tn's Long Tons Long Tons 1915
3,061,012 4,409, 167 15,198.803 15,266.155 4,893,101 5,434,046 1920
2,276,072 2,067,962 8,735,383 17,574.657 11.232,865 4,387,363 1925
5,640,298 5.206,983 14,130,667 26,761,935 23,697.285 5,881,691 1930
6,087,910 6,179,023 14.803,334 28,511,000 27,853.635 6,290.625 1931
7.273,886 6,036.980 16,189.074 25,332,000 22,034,433 5,898.289 1932
8,537,460 6.693.800 17.960.650 23,632,000 18.087.786 5,318,935 1933
9,194,130 6,951,064 18,780.489 26.915,000 21,146,760 5,389.069 1934
9,280,452 6,660,052 18.069.252 31.751,000 25,900.152 5,949,970 1935
8.953,383 6,873,655 18,205,989 32,810,968 24,701.904 6,135.003 1936
10,436,803 8.238,416 21,466,810 32,378,883 27,369,615 6,373,308 1937 11,747.950 9,195,439 23,348,477 36,491,332 29,298.766
12,629,054 9,236,318 24.636,462 34,418,000 26,227,268 6,409,873 1939
11.727,553 8,340,165 20,067.718 29,573,394 29.081,360 1940 12,909,597 7,479,617 22,875,668
26,546,579 There are no official traffic figures for Suez or Europe. Suez has been the object of attack from Manchester since the outbreak of the war in the air by German planes.
The cargo traffic on the Panama Canal (1940) (April, 1859) and was opened in Nov., 1869. The from the Atlantic to the Pacific totaled 9,954,009 canal is open to all nations and free from blockade. tons; Pacific to the Atlantic 16,592,570 tons.
by the Convention of Constantinople, signed (Oct. Passengers (1940) numbered 80,751.
29, 1888) by Britain, Austria-Hungary, France. The Suez Canal, which is 104.50 miles long, and Germany, Italy, the Netherlands, Russia, Spain, is at sea level, dates from 1869. It was begun and Turkey
Great American Dams
Height Million of Dam
Sta te Purpose Compl. (feet) (Gal.) (Dollars) Boulder
Ariz.-Nev. F. C., Irr., P. 1936 726 10.000.000 77.843,000 Shasta Sacramento Calll. F. C. Irr., P.
958.000 71,000,000 Grand Coulee, Columbia
Wash. F.C., Irr., P. 1941 553 3,131,000 118,000,00. Bonneville Columbia Ore.-Wash. P. N.
1937 170 Tuolumne Hetch Hetchy
Calit. W.S., P.
430 1,466,000 10,000,000 Kingsley.. North Platte Nebr.
6,534,000 19,300,000 Owyhee
3.880 2,514.770 Mokelumne Pardee
96,000 4,927.710 Mokelumne Salt Springs.
6.930,000 Merced Exchequer Calil. Irr., P.
94,200 5,116,073 Shoshone Shoshone.
228,000 9,000,000 Morris. San Gabriel
20.700 5.770,005 Lewis Ariel
N. M. Irr.
79,800 2,873.000 New Croton..
28,110 7.631,185 San Gabriel No 2. San Gabriel
4,560 3,007,5 Friant.. San Joaquin Calll. Irr.
290 147,000 19,900,000 Tuolumne Don Pedro
533,500 3,890,187 Cushman Skokomish
Calir. W. S.
17,500 Lake Spaulding. South Yuba
24,300 2,353,776 Verde
4,040,000 Dix River. Dix Kentucky P.
97,800 7,000,000 San Diego El Capitan.
38,400 3,124,908 Norris.
Nav. F.C.,P. 1936 265 1,108,400 13.800.000 Marshall Ford. Colorado Texas F. C., Irr., P.
1,000,000 25,500,000 Cobble Mountain. Little Massa W. S., P. 1932 263
264,500 6,000,000 Baker
8,000,000 No. Platte Seminoe,
F. C., Irr., P.
325,800 3.938,000 Lake Pleasant. Agua Fria
56,500 Olive Bridge.
1928 249 391.000 4,500,000
247 Copco No. 1..
25,100 1,544,000 Spokane Long Lake
1915 247 Calli. F.C.
1932 Big Tujunga No. 1. Big Tujunga Cr.
2,040 1,117,025 Fort Peck. Missouri
1939 242 6,350,000 86.000.000
1927 Big Santa Anita
1,208,000 Tygart W. Va
F.C Tygart River
232 106,600 15,700,000 No. Platte Alcova.
26,100 1,000,000 Little Tennessee Calderwood.
20,600 Calit. P.
10.400 Bouquet Cr.
3,007,586 Bouquet Canyon Note: F. C.=Flood Control; P.-Power; Irr. Irrigation; W. S.=Water Supply; Nav.=Navigation.
GRAND COULEE DAM, OREGON The Grand Coulee Dam turned over its first 1933, under the provisions of the National Ingenerator on March 22, 1941 (2 years ahead of dustrial Recovery Act. The project was formally schedule), and sent 10,000 of an ultimate capacity authorized by Congress in the River and Harbor of 1,974,000 kilowatts, or 2,475,000 horsepower, into Act approved August 30, 1935. It is located on the network of transmission lines of the Bonne- the Columbia River about 42 miles east of Portland, ville Power Administration. This agency is charged Oregon, and may be reached by railroad and highwith distribution of power from the Grand Coulee way. The main features of the work are a dam, and Bonneville projects over the Pacific Northwest. a powerhouse, a ship lock, and fishways. The
Improvement of the Columbia River at Bonne- total estimated cost of the project, with an inville, Oregon, was undertaken on September 30, stallation of ten power units is $75,000,000.
BONNEVILLE DAM, OREGON Improvement of the Columbia River at Bonne- direction of the Secretary of War and the superville, Oregon, was undertaken on September 30, vision of the Chief Engineer, U, S. Army. Present 1933, under the provisions of the National In- installed generating capacity at Bonneville is 194,
The project was formally dustrial Recovery Act.
400 kilowatts. Money has been appropriated. authorized by Congress in the River and Harbor numerous contracts have been let, and work is now Act approved August 30, 1935. It is located on the going forward toward the purchase or installation Columbia River about 40 miles east of Portland of the remaining six units in the powerhouse. Oregon, and may be reached by railroad and Transmission and sale of electric energy generated highway. The main features of the work are a at Bonneville along with that generated at Grand
Coulee dam is under the direction of the Secretary dam, a powerhouse, a ship lock, and fishways. The total estimated cost of the project, with an in- of the Interior and the supervision of the Bonnestallation of ten power units is $75,000,000.
ville Power Administrator, Portland, Oregon By The dam, locks, existing power plant with its April 15, 1941, a total of 38 contracts for sale of present installation of four units and appurtenant power had been signed. Of these, 28 were with works at Bonneville have been constructed, and public distributing agencies, three with private are being maintained and operated, under the utility companies and seven with industries.
BOULDER DAM (BOULDER CANYON) PROJECT
River 584 feet, Its length along the crest is 1.244
The dam rises 726.4 feet above bedrock, and is '26. 1936, during the construction period. Lake
Mead is the world's largest man-made lake, hav- John C. Page, Commissioner, Bureau of Reclamaing a capacity of 32,359,274 acre-feet of water, and tion, reported that the sale of power at Boulder Dam being 115 miles long and 8 miles in maximum for the fiscal year of 1940 amounted to $4,461,393.89 width. In February 1941, it had filled to more present power contracts will return the entire inthan 23,400,000 acre-feet.
vestment in the dam with interest at 4 per cent, Boulder Dam impounds in Lake Mead flood and will create a surplus in fifty years, Page's waters of the Colorado River for use in irrigation, report stated. The Bureau of Reclamation operin regulating the river, in flood control, silt control, ates the dam, and Boulder City: Los Angeles and improvement of navigation and in generating hy- the Southern California Edison Co., are in charge droelectric energy. The Imperial Valley, which lies of the power house; Lake Mead is controlled by below sea level in southern California, is dependent the National Park Service, for purposes of recreaupon Boulder Dam for protection from overflow, tion. The United States Government holds title to water shortage, and silt accumulation.
dam, power house, and equipment, Boulder City, The Boulder Dam power house will have an in- and the lake. stalled capacity of 1,835,000 horsepower. The first Erosion has so shortened the useful life of the unit was put in operation on Sept. 11, 1936. The water-supply reservoirs in the United States that power-house is to be equipped with 15 generating a hundred years hence only 54 per cent will provide units of 115,000 and two of 55,000 horsepower sufficient storage to meet present requirements, capacity. A battery of 8 of the big generators, according to H. S. Bennett, chief of the Soil Conlargest installed to date, and one of the smaller servation Service, said today. Over 20 per cent of generators are in operation. Two additional large the 12,000 or more reservoirs and dams have a useunits are being installed and one other is being ful life of fewer than fifty years and another 25 manufactured
per cent will be lost in fifty to 100 years, he stated.
FORT PECK DAM, MONTANA The Fort Peck Dam, constructed by the Army suction, dredge units; 4,000,000 cubic yards of Engineers on the Missouri River in northeastern gravel, and more than 1,000,000 cubic yards of rock Montana, is the largest earth-fill dam in the world. Four tunnels, 24 feet and 8 inches in diameter Construction was started in October, 1933. and the bypass water releases from the reservoir through dam was raised to its final height of 250 feet in the east abutment of the dam. All tunnels are October, 1940. The primary purpose of the dam, equipped with vertical-lift, tractor-type, emergency expressed in the authorizing acts, is for the im- gates. Discharges through three of the tunnels are provement of navigation on the Missouri River, controlled by cylindrical gates installed in and for the production of hydroelectric power con- vertical, circular shaft, 50 feet in diameter; and sistent with the primary demands of navigation. the discharge through the fourth or power tunnel Releases from the Fort Peck Reservoir for naviga- is controlled at the power house. A spillway with tion purposes were started in 1938.
16 vertical-lift gates, 25 feet by 40 feet, is located The dam has a total crest length of 4 miles, in the rim of the reservoir 3 miles east of the dam. comprised of the main section across the river A power plant, located at the outlet of one of valley of 10,578 feet and a large dike section on the tunnels and designed for an ultimate installathe west bank 10,448 feet in length. The average tion of three 35,000-kilowatt generators with an width of the base of the main structure is 3,500 initial installation of only two geenrators with a feet, and the top, on which a hard-surfaced road combined capacity of 50,000 kilowatts, is under will be constructed, is 100 feet wide. The dam construction at the present time. contains about 123,000,000 cubic yards of earth-fill It is expected that construction of all major material, placed almost entirely by full-electric, features of the project will be completed in 1943 FOREIGN DAMS
Hgh.ft. Mill. Gal. Cost Marathon, near Athens, (water supply) (1929)
10,800 $2,200,000 Sennar, Sudan, Blue Nile, near Makwar (1926); irrigation.
140,000 43,000,000 Assuan, Egypt, on the Nilc (1912, then enlarged); irrigation
144 1,322,955 29.000.000 Krishnaraja, British India: for irrigation..
45.000 13,000,000 Cauvery-Mettur, British India irrigation, power (1934)
214 5,978.750 16,000.00 Lloyd Barrage. Indus River, British India (1928-1932): irrigatlon
73,730,000 Hartebeestpoort, South Africa (1923)
410,000 8,000,000 *Dnelper River, Russia: power, etc.. (1932)
291,800 110,000,000 Sautet, Drac (Rhone trib.) River, French Alps, power (1936)
34,540 Barberine, Switzerland, Alps (1921); power.
82,809 20.000.000 Jandula, near Andujar, Spain (1930): power.
118,890) 5.000.000 Esla, near Zamora, Spain; power
264,200 12,000,000 Don Martin, Tamaulipas, Mexico (1930); power, etc.
131 359,267 8,000,000 Jerry O'Connell, Bananeiras, Bahia, Brazil; power
23.1001 5.000.000 *Destroyed by the Russians in August, 1941, to prevent its seizure and use by German war forces. The Cauvery-Mettur irrigation project; in Brit- beneath amounting to 1312 tons per square foot. Ish India, inaugurated in 1934, has the largest dam The reservoir behind the dam is 13 miles long, in the British Empire and one of the largest in 415 miles in its extreme width; its area is 60 the world. The dam, at Mettur, on the Cauvery square miles, with 180 miles of shore line. River, 180 miles southwest of Madras, is 5,300 One of the legendary sites of the Garden of feet long, and contains 5415 million cubic feet Eden is watered from a dam in Iraq, put in operaof masonry. weighing 3,640.000 tons. It is 171 tion in March, 1939, by King Ghazi. The dam. feet thick at the base and 2014 feet thick at the which was begun 16 years ago, has cost 512 million top; and It exerts a pressure on the ground dollars. The barrage is 1,615 feet long.
St. Lawrence Seaway Canal Project
Source: Reports to Congress The project calls for the construction of a 27-foot | ing a flow of 100,000,000 gallons of water per channel through the St. Lawrence River from minute and with foundations from 50 to 80 feet Montreal to Lake Ontario and from there through below water level the Welland Canal and other interconnecting lake In their report to the two governments dated rivers and canals. The total distance from Duluth November 16, 1926. the Joint Board of Engineers to open ocean would be 2,351 miles, and from estimated that the total cost to both countries Chicago to open ocean 2.250 miles.
would be approximately $427,000,000. Of this To make possible passage between the lakes, ob- amount, they estimated that $251,000,000 would be structions in the St. Marys River between Lakes the United States share and $176,000,000 the Superior and Huron have to be removed. The same Canadian cost. situation applies to the St. Claire River, Lake St. The Brookings Institution, in its St. Lawrence Claire, and the Detroit River between Lakes Huron report of 1929, estimated that $25,000,000 would and Erie.
have to be spent for each of 10 lake ports. The The total difference in water levels between Lake engineering department of the city of Buffalo has Superior and Lake Ontario would be overcome by estimated that complete Improvement of that harthe construction of a new lock in the St. Mary's bor would cost approximately $47,000,000, which River and by the improvement of the channels in sum would cover both private and public expense. the Welland Canal which has a total lift of 3252 The Department of Research of the United States feet.
Maritime Commission shows that for the calendar The most important part of the work is in the St. year of 1938 the total water-borne foreign comLawrence River where it is necessary to construct merce of the United States moving via the St. 9 locks, several side canals in the Lachine and Lawrence route amounted to 1,900,000 tons, and Soulange sections, and great dams and levees. that of this total 123,000 tons, a little over 6 per
Dams would be constructed across the river hay- cent, was handled in American ships.
The Great Lakes
Superior Michigan Huron Erie Ontario Length in miles.
192 Breadth in miles
53 Deepeut soundings in feet
778 Area (sq. miles) water surface-U. S.
20,710 22,400 9,110 4,990 3,560 Canada. 11,110
13,900 4,950 3,980 Total
31,820 22.400 23.010 9,940 7,540 Area (89. miles) entire drainage basia-U.S.
24,850 23,570 18.710
47.570 11,110 15.920 Total
80.900 69,040 72,420 34.680 34,630 Mean surface above mean sea level in feet.
602 13 579.74 579.74 571.86
245.62 Latitude, north...
46° 25' 41° 37' 43° 00 41° 23' 43° 11'
49° 00 46° 06. 46° 17' 42° 53 44° 15' Longitude, west.
84° 22' 84° 45' 79° 43' 78° 51 76° 03'
92° 06' 88° 02' 84° 45' 83° 29 79° 53' National Boundary line in mlles..
282.8 None 260.8
174.6 United States shore line in miles
303 Figures for mean surface above mean sea level 599.94 (April, 1926). Michigan, 582.28 (July, 1929); are the average for 41 years-1900-1940.
577.25 (Jan., 1926). Huron, 582.32 (July, 1929) Maximum and minimum monthly mean eleva. 577.35 (Feb., 1926). Erie, 584.27 (June, 1929) tions since 1900 of the surface of the Great Lakes 569.43 (Feb. 1936), Ontario, 248.62 (June, 1908); above sea level--- Superior, 603.64 (Sept., 1916): 242.68 (Nov., 1934).
LAKE ST. CLAIR Lake St. Clair is an expansive shallow basin of surface 180 is in the United States and 280 in the waterway through which Lake Huron dis- Canada. charges into Lake Erie. It has low marshy shores
The St. Clair river, about 40 miles long and and a natural maximum depth of about 21 feet. 8 to 14 mile wide, is the outlet from Lake Huron Its low-water datum is 573.5 feet above mean sea
to Lake St. Clair, and the Detroit river, about 27 level. Its extreme length is 26 miles and extreme
miles long and varying in width from one-hali width 24 miles. The improved steamer channel is Erie.
to three miles, flows from Lake St. Clair to Lake 186 miles long, with least width of 700 feet and Shoal sections of the rivers are improved and a depth of 25 feet. Of the 460 square miles of water 25-foot channel is maintained by the United States,
Area of Islands
Islands Miles Australia. 2.974,581 Greenland
827,300 Martha's Vine
375 Azores. 922 Great Britain. 88,745 yard
29.100 Batin Land 231.000 Guadeloupe..
1.307 Bahamas. 4,404 Guam
9,299 Balearic 1,935 Hawaiian 6,449 Marquesas 480 Scilly
30 Barbados 166 Hayti 28.954 Melville Land. 20.000 Seychelles
156 Bermudas 20 Hebrides 3,000 Mindanao 36.906 Shetland
351 Bismarck 15,752 Heligoland.
9.935 Borneo 306.906 Hainan 13,000 Nantucket
210 Bornholm 210 Hokkaido 30.340 Newfoundland 42.734 Solomon.
3,807 Canary.. 2.807 Hongkong
32 New Britain. 10.000 St. Helena Cape Breton 3,120 Honshiu.
87,426 New Guinea 330,000 Spitzbergen 30,880 Cape Verde 1,480 Iceland 39.709 New Hebrides. 5.100 Skye..
535 Carolina 560 Ireland 32,586 New Ireland
4.600 Southampton 17.800 Celebes 72.697 Isle Royal, Lak.
New Zealand 103. 568 South Georgia. 1.000 Ceylon
163,138 Channel 75 Jamaica. 4,2071 North Island. 45.068 Tahiti.
600 Corlu 277 Japan. 146, 106 North Devon 24,000 Tasmania.
26.215 Corsica. 3,367 Java
48,400 North Somerset 12,000, Terra del Fuego 18.500 (rete. 3,326 Jersey 45 Novaya Zernlya 30,000 Teneriffe
785 Cuba 44,164 Leeward
385 Curacao 403 Long Is, N. Y. 1.680Pemba.
1,750 Cyprus 3,584 Luzon 40,814 Penang
16,400 Ellesmere 40,600 Madagascar 225,000 Phillippines. 115,026 Victoria
74,000 Falkland 6,300, Madeira
132 Fiji ... 7,435 Madura.
2.000 Prince Albert L. 60,000 Whldby, Wash. 166.93 Formosa 13,911 Malta.. 118 Prince Edward 2,184 Windward
516 Frid. of Nansen 227 Prince of Wales 15,000 Wrangell.
18,000 Galapagos 2.868 Manhattan
21.9 Porto Rico
640 Gotland. 1,150
9701 Areas cover groups whenever the name itself in
Governors Isiand, in New York Harbor, has an dicates a group--Azores, Bahamas, Bermudas, etc. area of 172.35 acres.
Knots and Miles The U. S. and British Statute Mile is 5,280 feet the area of the surface of the earth. in length. On the Continent most of the old miles, The Geographic Mile is 6,087.1 feet in length which varied in length from about 3,300 feet to and equal to one minute of longitude of the equator. over 36,000 feet, have been replaced, officially at The Knot is a measure of speed; a speed of one least, by the kilometre, which eguals 0.62 statute knot being a speed of one nautical mile per hour. mile or 3,280.8 feet.
A Nautical Mile 1.152 statute miles; a Fathom The Nautical or Sea Mile at any place is con- -6 feet; a Cable-0.1 nautical mile, or 608 feet; sidered, for purposes of navigation, to be equal to also, 120 fathoms or 720 feet. the length of one minute of latitude at that place. To convert statute miles into nautical miles,
The Ŭ. S. Nautical Mile is 6.080.20 feet in length multiply statute miles by 0.8684; to convert nautiral and equal to one-sixtieth of a degree of a great miles into statute miles, multiply nautical miles by circle of a sphere whose surface is equal in area to 1.15157