The canal effort was begun by a French company (
La Compagnie Universelle du Canal Interoceanique) in 1880 to 1889. With poor exploration of the options and with poor information of the costs, the French company planned to construct a sea-level canal linking the two coasts. They initially thought they could do this for about $120 million. After spending about one billion Francs (about $300,000,000), losing about 22,000 workers and going bankrupt, the French effort essentially ceased. A sea level canal would not have required the dam to be built but would have still required extensive provisions made to accommodate the ever-changing Chagres River flow. The United States took over the wide
Canal Zone and resumed building the canal on 4 May 1904. Almost two years were spent in infra-structure preparation, mosquito abatement (the newly discovered
vector spreading
Yellow fever and
Malaria),
Panama Railroad improvements, and planning before the work got up to full speed. After reviewing the options and costs, in 1906 a lock-based canal was decided upon and agreed to by President
Theodore Roosevelt. Even before the lock canal decision was made, Major
George Washington Goethals (
United States Army Corps of Engineers), the chief engineer from 1907 to 1914 of the construction effort, had already carried out an investigation under
John Frank Stevens (chief engineer, 1905–1907) into determining the suitability of the land at Gatun for the building of a large dam there. Extensive test borings were made to determine the suitability of the land, and pressure tests were carried out on the material to be used in construction to determine its durability. The Gatun Dam serves two important purposes: it controls the ever varying Chagres River and creates Gatun Lake. The lake at about elevation provides an elevated path for ships across most of the
Isthmus of Panama including through the treacherous V-shaped Culebra Cut (Gaillard Cut). This saved excavating literally millions of cubic yards of material that would have been necessary for a sea-level canal. The lake height is regulated by spillways that control the water flow out of the dam to obtain an almost constant height in wet or dry seasons. The lake also acts as a massive reservoir to work the locks on both the
Pacific Ocean and
Atlantic Ocean ends of the canal and provides via hydro-electric generators about 6 MW of electrical power needed to run the locks and dam. After finishing the dam and filling Gatun Lake it was dredged where necessary to obtain a clear ship channel across the lake. The Gatun location was in most ways ideal for a dam; upstream of the dam site the hills enclosing the Chagres River opened very wide around the area that is now Gatun Lake. Over a narrow gap the hills close to a relatively narrow gap with a natural rock-based channel in the centre. This allows a moderately sized dam to enclose a huge body of water, which both provides passage for ships across much of the isthmus, and provides a
reservoir of water with which to operate the locks. The central hill was the ideal solid base for the construction of the concrete spillway and its dam, the main part of the dam being earth. The only problem was the huge scale of the dam required massive rock and dirt fill that was provided by about 100 trainloads of waste rock deposited into two parallel walls of waste rock about apart every day for several years from the Gaillard Cut (now called the Culebra Cut) and the Gatun Locks excavation. Between these waste rock walls an impervious core was created by using a
hydraulic fill technique which pumped millions of cubic yards of clay material and water into the area between the rock walls. This fill was made by digging up the soft clay present in the valley below, where dredges excavated the clay and water and loaded it into pumps that delivered it up into a pond created between the inner and outer walls of the dam. The pumped mixture was allowed to sit until the clay settled out, with the excess water being drawn off and pumped back downstream. This dried and hardened material created a solid core of "natural" cement at the core of the dam. After the dam was built to its desired height, the entire up-stream side was armored to prevent wave action damaging the dam by placing large boulders on the face, particularly where there is strong wave action. The dam contains some of material and is about wide at its base, about high and long. The dam weighs some . It covers of ground, and contains enough earth and rock to build a wall metres high and 29 cm thick (or four foot eight inches high and a foot thick) around the Earth at the equator. ==Water level==