Cabrera was a surveying engineer from Canelones, and former senator of the Republic, who participated in the previous civil revolution of 1897. In 1904 he was political head of the Department of Rivera, and in the 1904 revolution he joined the army of Aparicio Saravia with the rank of Colonel, second Chief and Head of Division No. 13.

At the beginning of the revolution, the bulk of the Saravia army was south of the Negro River, fighting with the army of the General Justino Muniz government. On January 14, Muniz defeats Saravia in Mansavillagra, the first major battle of the revolution. The army of Saravia must retreat to the North, until receiving support weapons from Buenos Aires by the War Council and members of the Directory exiled in this city.

The three bridges mentioned were; first bridge in the “Paso de Carpintería”, second bridge in the “Paso de Mazangano”, third bridge in “Picada de Osorio” or “Puerto Osorio”.

In order to make inland navigation effective, in 1906 the Minister of Development, engineer Juan Capurro, ordered the construction of three cargo steamers from the English firm Harrow & Co., at a price of 2,140 pounds each. Subsequently, two further passenger steamers are ordered at a cost of £2,700 each. All of these are named “Peace”, “Order”, “Liberty”, “Progress” and “Liberty”.

In 1906, the first “Inland River Navigation Office” was installed in Santa Isabel, currently Paso de los Toros, dependent on the Ministry of Development (current Ministry of Transportation and Public Works of Uruguay), which will have particular relevance for the subsequent collection of all the hydrometry information (scales, gauges, profiles) necessary for the subsequent construction of the Rincón del Bonete dam. The Office had the new river steamers with a large nautical beam and low depth, which allowed passengers to navigate from “Paso Ramírez” to Mercedes (Uruguay) "Mercedes (Uruguay)") and to Montevideo through the Uruguay River and the Río de la Plata.

Víctor Soudriers, a Uruguayan engineer in bridges and roads, a civil engineer working for the army, is sent to the Negro River to inspect the bridges built by Carmelo L. Cabrera during the 1904 Revolution, envisioning the hydroelectric use of the Negro River. Soudriers served in the national army, where he participated in the construction and removal of floating bridges over the Negro River, directly witnessing the flooding of the Negro River. The place chosen for the bridges is the pass over the river called “Picada de los Ladrones”.

Since 1906, the Negro River was an important navigation route, with height scales installed at various points, which were read and recorded daily. The leveling and planimetry of the river was carried out by engineer Alejandro Rodríguez, from the Hydrography Directorate.

In 1906, work on topographical surveying, altimetry and planimetry of the Río Negro began. Between approximately 1910 and 1920, engineer Ale Rodríguez worked for the Military Geographic Service, in a far-reaching task, he carried out a survey of the Negro River to study the possibility of taking advantage of hydraulic resources to produce electrical energy. In parallel, the French artillery colonel and Geodesta, a specialist in geodesy, Paul Gros arrives in Uruguay, and working for the Military Geographic Service"), begins the triangulation of the department of Durazno. This first datum of the Negro River would later determine what is currently called Cero Bonete, when the Río Negro Dam (Rincón del Bonete) was built, referencing its vertical levels against the official zero level of Montevideo at the beginning of the century, which presents a difference of -0.61 m with respect to the current zero +0.00 m current official.

The Hydrography Directorate (current National Hydrography Directorate) was created from the Interior River Navigation Office. Thus began the development of inland navigation in Uruguay as a fundamental activity in the transportation system of the time. It should be remembered that in 1906 there were no roads and the railway system was just in its beginnings, so river transport of both cargo and passengers was the most suitable means of transport at the time. From 1909 onwards, the Hydrography Directorate began the preparation of maps with the topography and altimetry of the Negro River, scales were installed to indicate the height of the waters, based on reference markers, installed by the Military Geographic Service, and referred to the zero of Montevideo (Zero Wharton).

In 1908, the engineer Soudriers requested a technical-economic proposal from the London engineering firm "J.G. White Engineering Corporation", with which he had already worked on the electric tram networks in Montevideo. The engineer Robert Barwell tours the Negro River, choosing the so-called “Picada de los Ladrones” as the appropriate place to build the dam, km 546 upstream of the Uruguay River, a navigation lock and power plant of 20 MVA power and a transmission line to Montevideo of 30 MVA, with a cost of $8,133,950, which was rejected due to excessive cost for the time, in favor of the new Calcagno thermoelectric plant.

In 1916, the engineer Soudriers delivered the preliminary hydrological studies to the company “Ulen & Co”, present in Uruguay in the construction of sanitation and drinking water works, also with experience in dams in the United States. Ulen & Co. presents a detailed report, once again recommending “Picada de los Ladrones” or “Rincón del González” as possible sites to build the dam, with a power of 40 MW, dam lengths of 2000 or 1400 meters respectively, and an estimated cost of about 15 million Uruguayan pesos (pesos at the time).

In 1923, the engineer Pierre de Kalbermatten and the geologist Michel Lugeon were hired to deepen the studies for the Río Negro dam. The sites were evaluated and discarded for various technical reasons; “Isla González”, “Picada de los Ladrones”, “Isla de la Rosa”, and the “Perfil de Sarandí” discarded after drilling, where sandy areas more than 20 meters deep were found. Finally, it was decided to continue the studies of the dam, locating it on “Isla González”, with the objective of damming the river with a water fall of 25 meters, to produce a power of 60 MW.

In 1924, the first gauging station (measurement of the river flow) was installed by the Ministry of Public Works in the Sarandí profile, 171 km upstream from Paso de los Toros.

Cabrera was a surveying engineer from Canelones, and former senator of the Republic, who participated in the previous civil revolution of 1897. In 1904 he was political head of the Department of Rivera, and in the 1904 revolution he joined the army of Aparicio Saravia with the rank of Colonel, second Chief and Head of Division No. 13.

At the beginning of the revolution, the bulk of the Saravia army was south of the Negro River, fighting with the army of the General Justino Muniz government. On January 14, Muniz defeats Saravia in Mansavillagra, the first major battle of the revolution. The army of Saravia must retreat to the North, until receiving support weapons from Buenos Aires by the War Council and members of the Directory exiled in this city.

The three bridges mentioned were; first bridge in the “Paso de Carpintería”, second bridge in the “Paso de Mazangano”, third bridge in “Picada de Osorio” or “Puerto Osorio”.

In order to make inland navigation effective, in 1906 the Minister of Development, engineer Juan Capurro, ordered the construction of three cargo steamers from the English firm Harrow & Co., at a price of 2,140 pounds each. Subsequently, two further passenger steamers are ordered at a cost of £2,700 each. All of these are named “Peace”, “Order”, “Liberty”, “Progress” and “Liberty”.

In 1906, the first “Inland River Navigation Office” was installed in Santa Isabel, currently Paso de los Toros, dependent on the Ministry of Development (current Ministry of Transportation and Public Works of Uruguay), which will have particular relevance for the subsequent collection of all the hydrometry information (scales, gauges, profiles) necessary for the subsequent construction of the Rincón del Bonete dam. The Office had the new river steamers with a large nautical beam and low depth, which allowed passengers to navigate from “Paso Ramírez” to Mercedes (Uruguay) "Mercedes (Uruguay)") and to Montevideo through the Uruguay River and the Río de la Plata.

Víctor Soudriers, a Uruguayan engineer in bridges and roads, a civil engineer working for the army, is sent to the Negro River to inspect the bridges built by Carmelo L. Cabrera during the 1904 Revolution, envisioning the hydroelectric use of the Negro River. Soudriers served in the national army, where he participated in the construction and removal of floating bridges over the Negro River, directly witnessing the flooding of the Negro River. The place chosen for the bridges is the pass over the river called “Picada de los Ladrones”.

Since 1906, the Negro River was an important navigation route, with height scales installed at various points, which were read and recorded daily. The leveling and planimetry of the river was carried out by engineer Alejandro Rodríguez, from the Hydrography Directorate.

In 1906, work on topographical surveying, altimetry and planimetry of the Río Negro began. Between approximately 1910 and 1920, engineer Ale Rodríguez worked for the Military Geographic Service, in a far-reaching task, he carried out a survey of the Negro River to study the possibility of taking advantage of hydraulic resources to produce electrical energy. In parallel, the French artillery colonel and Geodesta, a specialist in geodesy, Paul Gros arrives in Uruguay, and working for the Military Geographic Service"), begins the triangulation of the department of Durazno. This first datum of the Negro River would later determine what is currently called Cero Bonete, when the Río Negro Dam (Rincón del Bonete) was built, referencing its vertical levels against the official zero level of Montevideo at the beginning of the century, which presents a difference of -0.61 m with respect to the current zero +0.00 m current official.

The Hydrography Directorate (current National Hydrography Directorate) was created from the Interior River Navigation Office. Thus began the development of inland navigation in Uruguay as a fundamental activity in the transportation system of the time. It should be remembered that in 1906 there were no roads and the railway system was just in its beginnings, so river transport of both cargo and passengers was the most suitable means of transport at the time. From 1909 onwards, the Hydrography Directorate began the preparation of maps with the topography and altimetry of the Negro River, scales were installed to indicate the height of the waters, based on reference markers, installed by the Military Geographic Service, and referred to the zero of Montevideo (Zero Wharton).

In 1908, the engineer Soudriers requested a technical-economic proposal from the London engineering firm "J.G. White Engineering Corporation", with which he had already worked on the electric tram networks in Montevideo. The engineer Robert Barwell tours the Negro River, choosing the so-called “Picada de los Ladrones” as the appropriate place to build the dam, km 546 upstream of the Uruguay River, a navigation lock and power plant of 20 MVA power and a transmission line to Montevideo of 30 MVA, with a cost of $8,133,950, which was rejected due to excessive cost for the time, in favor of the new Calcagno thermoelectric plant.

In 1916, the engineer Soudriers delivered the preliminary hydrological studies to the company “Ulen & Co”, present in Uruguay in the construction of sanitation and drinking water works, also with experience in dams in the United States. Ulen & Co. presents a detailed report, once again recommending “Picada de los Ladrones” or “Rincón del González” as possible sites to build the dam, with a power of 40 MW, dam lengths of 2000 or 1400 meters respectively, and an estimated cost of about 15 million Uruguayan pesos (pesos at the time).

In 1923, the engineer Pierre de Kalbermatten and the geologist Michel Lugeon were hired to deepen the studies for the Río Negro dam. The sites were evaluated and discarded for various technical reasons; “Isla González”, “Picada de los Ladrones”, “Isla de la Rosa”, and the “Perfil de Sarandí” discarded after drilling, where sandy areas more than 20 meters deep were found. Finally, it was decided to continue the studies of the dam, locating it on “Isla González”, with the objective of damming the river with a water fall of 25 meters, to produce a power of 60 MW.

In 1924, the first gauging station (measurement of the river flow) was installed by the Ministry of Public Works in the Sarandí profile, 171 km upstream from Paso de los Toros.

In March 1935, the Engineer Battalion No. 3 (Uruguay) moved from Rivera to its new headquarters in Paso de los Toros. He passes to this town, occupying the Barracks that the Infantry Battalion No.10 will hand over. Part of the premises, which still remain in their current headquarters, were the warehouses of the first and most important industry that Paso de los Toros has had: the saladeril (salting factory) founded in 1884 by Don Juan André and Don Valentín Piñeyrúa. Among the many tasks assigned to Battalion No. 3, the important one for the history of the dam was the construction of the Rincón del Bonete landing strip (parallel to the road, located on the left hand side reaching Rincón del Bonete and before reaching the gap), which in the 1959 flood allowed the establishment of an air bridge with helicopters with Rincón del Bonete and with Paso de los Toros with civil aircraft, evacuating the dam personnel who remained there to dismantle the generating turbines before the waters covered them.

The initial cost of the work was financed with the issuance of public debt for 48:$ (48 million pesos), law of February 1934. The total final amount of the budget for the work reached close to 50:$ (millions of pesos), almost 1/6 of the GDP (gross domestic product of the time), composed of; 41:$ including interest to be paid to the German consortium, plus 5:$ in expropriations, 1.4:$ for the waterproofing of the subsoil, $740,000 in administration expenses, $300,000 in housing, the railway to Paso de los Toros $130,650, and $400,000 for the diversion of the railway line in Cardozo town.

The contract for the construction of the dam, between the German Consortium and the UTE, was signed on April 15, 1937, establishing that the work should be completed on April 30, 1942. [1] The contract established the total price (the subsoil waterproofing injections were in a separate contract) of the works; $17,744,776.67 (seventeen million Uruguayan pesos), plus £2,344,871 (two million British pounds). By way of comparison, the Grand Coulee Dam, built in its first stage between 1934 and 1943, and about seven times the size of Rincón del Bonete; cost $163 (one hundred and sixty-three million dollars). The payments necessary for the completion of the work, after the events caused by the Second World War, raised the total cost of the work to 107:$ (107 million pesos, equivalent to the cost of 50,000 automobiles). The monitoring and receipt of materials or equipment in the factory would be by Bureau Veritas. The contract, as usual, established multiple amendments to the bidding document, negotiated between UTE and the German consortium. The German generators would be; two part of the house Siemens Schuckerwerke-Gesellschaft A.G. (S.S.W.), and two others by Allgemeine Elektricitats-Gesellschaft A.G. (A.E.G.).

Today it seems difficult to believe that the dam was built with German Portland cement and not with national cement, but in 1937, Uruguay did not have factories capable of producing the volumes and quality of cement that such a work required. The German cement brought into the country would be tested on samples of each shipment, to be carried out at the Materials Testing Institute of the Faculty of Engineering (University of the Republic). The price of German Portland cement was 17 Uruguayan pesos per ton.

On May 18, 1937, the foundation stone was placed on 18 de Julio Avenue, almost Sarandí, in the flowerbed of the avenue in front of the Paso de los Toros plaza. A crowd of 12,000 people, many of them UTE officials, was transported by train from Montevideo to Paso de los Toros, to a party where food was distributed to the needy population, military bands, a barbecue with leather in the Municipal Park, and a flight of Army planes (the Air Force did not yet exist), and PLUNA.

A day before, the 4 new Brill model 60 motorcars (no. 129, 130, 131 and 132) had been expressly sent by rail from Montevideo, coupled together and completely empty, arriving at their destination, at the Paso de los Toros station in the department of Tacuarembó, in the afternoon, the objective of their trip being to exhibit them to the community. The Brill cars caused great admiration, they spent the night at the station and remained detained until the next day, when two trains arrived with the procession. The second of them, towed by the Class S locomotive No. 144, was the one who brought the wife of President Gabriel Terra, since he, fearing an attack on his life, could not attend the event. They had already tried to assassinate him in 1935 at a meeting in Maroñas that he attended with the Brazilian president Getulio Vargas. President Terra sent a one and a half hour speech that was broadcast over a network of speakers, which was followed by the singing of the national anthem and words by the Minister of Public Works Dr. Martín Echegoyen, the German Ambassador to Uruguay Hans Moraht and the representative of the German Consortium Dr. Karl Stoop.

To close, two telegrams were read between the presidents of Germany and Uruguay, on the occasion of the laying of the foundation stone that began the work:

"Berlin, May 17, 1937. Your Excellency President of the Eastern Republic of Uruguay, Dr. Gabriel Terra. On the success of the monumental work of the Río Negro, begun at the initiative of your government, I express to your Excellency my most sincere congratulations. Adolfo Hitler, Chancellor of the Third Reich."

And this answer:

"Montevideo, May 17, 1937. To Your Excellency Mr. Adolfo Hitler. Führer Und Reichkanzler. Berlin. I thank Your Excellency for your cordial congratulations on the occasion of the initiation of the hydroelectric works on the Río Negro. I trust in their success because they will be carried out by German technicians of great scientific reputation and honorable tradition. Our country will never forget everything that Your Excellency's government has done to facilitate the execution of the contract. And I am sure that through these works, whose initial impulse is celebrated today by the Uruguayan people, our two countries will feel more linked every day in their firm friendship. Gabriel Terra, President of the Republic."

On September 28, 1938, at the request of the new elected President, General Architect Alfredo Baldomir, as the “Honorary Commission for Financial Supervision of the Works” (from April 12, 1937) could not adequately fulfill its function as controller, which overlapped with the controller of UTE, the Technical and Financial Commission of the Hydroelectric Works of the Río Negro was created, better known as “The RIONE.”

Law No. 9786; Article 1: The Technical and Financial Commission for the hydroelectric works of the Negro River is created. Its relations with the Executive Branch will be through the Ministry of Public Works, without prejudice to the intervention of the Ministry of Finance in the relevant matters. It will have an honorary character, it will enjoy legal status and its functions will last until the completion of the tasks assigned to it. It will be made up of a President and four members, both appointed by the Executive Branch, one of them as a delegate of the Ministry of Public Works and the other of the Treasury; and will also be integrated as ex officio members with the Presidents of the Bank of the Republic and the U.T.E. and the Directors of the Geological and Hydroelectric Studies Institute.

The commission would be directly dependent on the Hydroelectric Studies Commission, headed by Eng. Víctor Soudriers and headed by the Minister of Public Works, with legal status, and until the end of the work. "You should adjust your budget to the $754,000 planned for the Construction Management").

In August 1937, the assembly of the warehouses, layout of the streets, homes, squares, sports fields, social club, canteen, dining room and school began. Surface covered by constructions adding; 5450 m² in homes and 3230 m² in warehouses.

In particular the homes of CONSAL staff and RIONE construction controllers; 2 temporary wooden bedrooms for CONSAL, 1 kitchen dining room for CONSAL, 8 dormitory sheds for 88 workers each, one for sub-foremen and married officers, 5 series of toilet services, 2 series of 8 homes for foremen, 2 series of 4 homes for engineers and superintendents of the RIONE, series of 8 homes for sub-foremen and married officers of CONSAL, premises for the administrative offices of CONSAL and RIONE construction control, sanitation network, drinking water and low voltage electricity, layout, street arrangement, 200 m³ raw water tank, 100 m³ drinking water tank. Urban planning would be in charge of Architect Julio Vilamajó.

In November 1937, construction of the 11 km of railway between Rincón del Bonete and Paso de los Toros began. The work ended in January 1938, during which time the material arriving from abroad for the work was accumulated at the Paso de los Toros railway station. The 14 km of the road between Bonete and Paso de los Toros, with streams without bridges (El Sauce, Las Nutrias, Sauce de Albuquerque), did not allow passage other than carts pulled by oxen.

The aggregates (stones and gravel) for the work were extracted from the area adjacent to the work, with a crushing plant with 3 breaking machines of 80m3 per hour, washing machines, vibrating screens and cement mixers. The sand was extracted from the river and stored in silos. The movement of aggregates and concrete was carried out in narrow gauge trains and wagons, Via Decauville of 600 mm, which ran through the work, or by means of a cable rail from one bank to the other.

In total the equipment of the quarry was made up of: 1 excavator shovel, 2 160 HP locomotives, 2 percussion drills, 5 pneumatic hammers, 1 dewatering pump. Between August 1, 1938 and November 30, 1939, they were extracted from the quarry; 43,208 m³ of material, of which 37,374 m³ went to the crushing plant and 5,834 m³ were rejected.

In December 1937, work began on the foundations for the crushing facility, which was completed and tested in July 1938. The crushing plant includes: a primary breaker with a performance of 80-100 m/hour, two secondary crushers with a performance of 80 m/hour, two washing machines with a diameter of 2 meters and a drum length of 7 meters, two vibrating screens, in four sections. staggered that separate the material into grain groups of 0-7; 7-15 and 17-60 mm.

For the preparation of intermediate granulated material there are three fine material crushers with a total capacity of 40 m³/hour. It also includes the river sand separation facility with a performance of 50 m³/hour, main tanks, and aggregate silos with their dosing devices at the bottom of these, and the conveyor belt systems necessary for the entire facility.

It consisted of; the cement tank, the endless conveyor for it, the compensating silo directly on the automatic scale that weighs the cement according to the established proportions. The aggregated materials are transported from the already provided silos to the mixer by conveyor belts. Two mixers with a capacity of 1500 liters each.

A cable rail transports the materials to the left bank (Durazno side) of the river, where silos accumulate the aggregates.

About 1,000 workers and numerous machinery were used for concreting (5 Wolf "Crane (machine)" cranes, 4 narrow gauge (600 mm) diesel locomotives). The total reinforced concrete of the dam is 350,000 m³, using 77,000 tons of cement and 60,000 tons of iron.

The D2 "M" type concretes with 280 kg of cement per m³ were tested for compression in specimens; 20 x 20 x 20 cm cubes, resulting in a compression breaking load of 150.7 kg/cm² (average of 199 tests) after 7 days of setting, and a breaking load of 252.4 kg/cm² (average of 192 tests) after 28 days of setting.

The flexural tensile tests on unreinforced beams measuring 15 x 10 x 70 cm resulted in an average breaking load of 37.4 kg/cm² (average of 54 tests) at 7 days of setting, and a breaking load of 51.5 kg/cm² (average of 127 tests) at 28 days of setting.

The permeability tests were carried out on a 10 cm thick plate with a surface area of ​​200 cm². The results were for; 1 atm of pressure for 24 hours: they permeated 0 cm³ of water (average over 115 tests), at 3 atm of pressure for 24 hours: they permeated 1.6 cm³ (over 115 tests), at 7 atm of pressure for 12 hours: they permeated 12.1 cm³ (over 109 tests).

The total number of railway tracks in the workshop and work in the cofferdam ditches 1 and 2 included: 1000 linear meters of normal or international gauge of 1435 mm, 7600 meters of gauge of 900 mm (3', three feet wide), 2000 meters of narrow Decauville gauge of 600 mm (1' 11"), and the cable rail to transfer materials to the left bank. (Peach).

The railway between Paso de los Toros and Rincón del Bonete entered service on January 30, 1938, transporting materials previously stored at the Paso de los Toros train station. Passenger service was inaugurated in May 1938.

On January 17, 1938, construction of the service railway bridge that crosses the Río Negro downstream of the works begins. Construction is interrupted by the flood from April 21 to May 26, 1938, and a second flood from June 27 to September 7, 1938. Construction ends on June 13, 1939. The bridge has a length of 300 meters, in 25 sections of 12 meters each.

It is currently known as the “broken bridge” after the 1959 flood swept away its beams and pillars.

The so-called temporary electric power generation plant includes the building, the cooling water and diesel fuel oil tank, and the electrical installations for a total of 2,500 HP. The engine-generator groups consisted of; 1 auxiliary group of 80 KVA, 2 diesel generator groups of 520 HP each, 2 groups of 500 HP each. A fifth group of 500 HP is installed in 1939. As an example, the energy generated between May 1, 1938 to November 30, 1939 was; 4,442,225 kWh.

The water treatment plant, for the purification of the raw water of the Negro River by flocculation and decantation by application of alumina sulfate, came into service on August 16, 1938. Previously, in 1937, the service water, for the work and the drinking population, still non-potable water, was provided from a temporary water intake, upstream of the cofferdam of Ditch No. 1, passing it through a filter of sand and chlorinator with sodium hypochlorite.

The start of the first cofferdam, Foundation Trench No. 1 (right bank, Tacuarembo side), began to be assembled on September 16, 1937. The two starts of the cofferdam are composed of two rockfills in a concrete core with a total length of 68 meters. On November 6, the placement of the 4,006 steel sheet piles, in 37 round cells, and the filling of clay sand begins. Metal steel sheet piles from Bethlehem type SP 6 and FT 60, lengths 11.0 and 12.2 meters. Ditch No. 1 was completed on February 14, 1938, with a perimeter of 537 meters that enclosed an area of ​​30,000 m². The draining was carried out between February 17 and 19, with 3 160 HP (horsepower) steam locomotives used to move the pumps to first empty and then bilge the water trapped by the cofferdam and subsequent leaks. The openings of Trench No. 2 (left bank, Durazno side) were built in openings 57 meters long. A third cofferdam, Trench No. 1a, was necessary for the excavation of the lower channel, this downstream and outside of Trench No. 1 described above. This auxiliary cofferdam was built as an embankment of material from the same excavation, between March 26 and April 28, 1939, with a volume of 1278 m³ of material.

On October 22, 1937, excavation for the dike began on the right bank outside Trench No. 1. In March 1939, excavation work began inside the ditch itself, which was completed in December of the same year. The total excavated for the dike, buffer bed and guard wall within Trench No. 1 reaches 2,406 m² of loose soil and 60,960 m³ of rock, including additional excavation to deepen the foundation of the landfill buttresses. In the dike area, within Trench No. 1, the volume of rock excavated was 38,300 m³.

On the left bank, Trench No. 2, the loose soil excavation work began on May 24, 1939 at the track and assembly site for the excavators, with 63,678 m³ of loose soil and 1,562 m³ of rock having been extracted by November 30. In the lower channel of the plant, 65,898 m³ of rock were excavated, of which 44,495 m³ were outside the cofferdam of Trench No. 1. Of the rock table, 28,847 m³ were destined for the crushing plant for use in concrete.

The excavation equipment within Trench No. 1 consisted of: 2 Demag shovels of 150 HP and 1,350 m³ capacity, 1 Demag shovel of 150 HP and 1,600 m³ capacity, 1 Demag shovel of 75 HP and 1,000 m³ capacity, 1 M&K shovel of 160 HP with 2,200 m³ capacity, 1 shovel O&K with a 750 liter grapple, 1 O&K shovel with a 300 liter grapple, 1 5 ton pile hammer powered by a compressed air pile driver, 3 locomotives of 160 HP, 3 locomotives of 200 HP. On the left bank, Trench No. 2, the 150 HP-1,350 m³ Demag shovel, the 2 160 HP locomotives and their respective dump cars, 1 52 HP compressor and drilling machines were used. In the area of ​​Trench No. 1, 3 excavator shovels, 3 160 HP locomotives and their dump cars were used.

On August 29, 1939, the concreting of the pump well with 2,406 m³ began, the Assembly Room continued up to a level of +65.00m with 850 m³ of concrete, and the infrastructure of the Machine Room; 29,246 m³. Concreting began on the buffer bed on September 22, 1938 with 3,400 m³, continued on the guard walls with 4,686 m³, and foundation of the buttress with 11,737 m³ and elevation works. Until November 30, 1938, the round-headed buttresses carried 41,749 m³, the water intake structure; 6015 m³, the landfill folder; 523 m³ and buttress foundations 673 m³. The concreting of the pillars of the 170 KV High Voltage Station began on February 25, 1939, with 5,680 m³ of concrete used in the foundation and pillars, a volume of 480 m³ for the slab and beams of the platform of the esplanade adjacent to the power plant.

The concrete placement equipment used consists of 4 60 cm gauge diesel locomotives with special tacho cars, 5 Wolf cranes, 1 conveyor bridge, discharge chutes and vibrators.

The foundations of the dam, despite being within the basaltic region, were reinforced with waterproofing curtains; numerous injections of cement (1500 tons) and chemicals (198 tons of sodium silicate and 73 tons of calcium chloride), into the altered or porous basalt layers. In accordance with the contract of April 15, 1937, a second contract had to be signed to resolve the problems and injections of the subsoil of the foundation of the dam, in order to compact it and waterproof it as much as was technically possible.

Achieving a completely impermeable curtain under the dike was assumed to be something impossible to achieve, which is why a degree of permeability of 1 liter per linear meter per minute was defined, under a water pressure of 4 atmospheres, a pressure measured in a vertical section 4 meters high.

The 9,850 drillings with a diameter of 60 mm (2-3/8 inches) were made dry, inside the trenches and their cofferdams. The start of each drilling using 100mm diameter steel pipes, from which the drilling machines reached a depth of +25.00 m underground, about 25 or 30 meters below the bed of the Río Negro, all along the dam in 3 parallel planes, the drillings separated by 4 meters from each other, and alternating in a staggered pattern. 9 Ingersoll Rand drilling machines, model COROC MD2, were used, and the injections were carried out with 5 Svenska Diamant Borrings A.B. equipment powered by compressed air. Starting before the signing of the drilling and injection contract, in September 1938.

The injections were carried out in 3 stages, at different injection pressures; the first stage at 7 atm. pressure and capacity of 3 liters per minute of cement slurry 1686 tons and chemicals (sodium silicate 198 tons and calcium chloride 73 tons), slurries with a density of 1.8 kg/L, the second stage at 11 atm., the third stage at 15 atm. and the fourth stage at 20 atm. Cement quantities of 2000 kg in stage 1 and 2, and decreasing to tens of kg of slurry; cement dissolved in water. Before and after the final stage, the hydraulic test was carried out at 4.5 atm. of pressure with water, re-drilling a few hours after the injection has been carried out. The overall and average results of all injections were highly favorable, reaching water permeability values ​​of 5 liters per minute per linear meter applying a pressure of 10 atmospheres.

In the scenario of the Second World War, Hitler invades Czechoslovakia on September 30, 1938, which triggers actions due to the imminent stoppage of the Rincón del Bonete construction work. On May 25, 1939, a modification of the Contract was signed between Uruguay and Germany, modifying the payment method provided for on April 15, 1937, and providing for the suspension of work in the event of bankruptcy, insolvency, impossibility of delivering the material in Montevideo, machines and parts, or due to war affecting Germany. In the event of interruption of the work, the return of the pledge as collateral for the clause would be carried out by the German Transatlantic Bank (Deutsche Überseeische Bank). the Montevideo branch. In August 1939, delays in the manufacture of "alternators" in Germany were evident, due to the lack of copper, which could only be acquired by Germany from the United States of America or Canada.

On September 1, the German Invasion of Poland in 1939 began. The J.M. equipment Voith of turbine No. 1; ring of sleepers, spiral box and the support of the A.E.G. generator, are detained in the port of Vigo Spain, awaiting procedures with the Allies to authorize their shipment to South America and Uruguay. Downstream closure boards, upstream closure cofferdams, and two of the four intake roller gates are stopped in Italian ports.

On December 17, 1939, in the so-called Battle of the Río de la Plata, three English warships inflicted serious damage on the German battleship Graf Spee, forcing it to be sunk by its captain near the port of Montevideo. From that fact, it became impossible to ship the electromechanical parts (turbines and generators) from Germany, and to pay for them with merchandise or cash shipments from Uruguay to Germany, even using merchant ships from or to neutral countries"), and between neutral ports (such as those in Spain or Portugal).

In 1941 the British ambassador to Uruguay Sir Ralph Skrine Stevenson; informs the Uruguayan government that the Ministry of War of its country would authorize these parts of the turbines from Germany, which thanks to merchant ships flagged by neutral countries were already in the ports of Santos and Rio de Janeiro in Brazil, and Valparaíso in Chile. This was on the condition that Uruguay did not issue payments for the works that arrived in Germany, and that the remaining orders for supplies of German equipment were cancelled. So the engineer Luis Giorgi begins the steps to acquire equipment in England first; Casa Vikers for the turbines, and English Electric for the generators. Finally, in 1942, the agreement was finalized with the government and the EXIM ("Export-Import Bank) of the United States.

First on a personal initiative, and later as state negotiations, Luis Giorgi began negotiations to purchase electromechanical equipment in the United States of America. The entry into war of the United States with the powers of the Rome-Berlin-Tokyo Axis, after the attack on Pearl Harbor, conditioned Uruguay to break off negotiations with the German consortium. The executive accepted the terms, setting the date of July 1, 1942 for the end of the contract with CONSAL, or an earlier date if the equipment was supplied from the United States. The transaction would be completed with the opening of the letter of credit before the Export and Import Bank, for 4: USD (4 million dollars) for a first generator and transmission line, and 8: USD (eight million dollars) for the remaining generating sets and second transmission line.

Three important floods exceeded 5,000 m³/s in 1941, floods only previously surpassed by the flood of 5,400 m/s in September-October-November 1918, a flood of 5,100 m³/s in 1925, and the flood of 8,300 m³/s in 1888 (historic for reaching the railroad bridge in Paso de los Toros). (elevation +62.43 m on the rails).

The first flood was in the months of February and March 1941, the second in April-May-June and the third in July-August-September 1941, destroying the work on the cofferdam and civil works in Trench No. 2 on the left bank (Department of Durazno side). The 1937 contract anticipated the flooding of the Río Negro up to a level of 60.60m upstream of the work and 59.50m downstream of the work. From those heights, it would be considered a flood in a "force majeure" situation.

On December 9, 1941, Uruguay prohibited trade and transfers of funds with Germany, Italy and Japan. On January 25, 1942, Uruguay broke diplomatic relations with Germany. On May 7, 1942, the Contract with CONSAL was terminated, by Decree of the President of the Republic, General Architect Alfredo Baldomir. Consequently, in July 1942, 95 German technicians and about 20 families left the work.

At the time of termination of the Contract with CONSAL, the dam was almost completed, the pressure tubes in the four turbines, the intake gates and their servomotors, the pump room thereof, the intake grates, the spiral casings, the rings and predistributors, the discharge suction tubes and their service closures, the upstream sieve cleaning crane and the downstream service crane, the civil works of the command house and offices, and the turbine room. No work had been done on the construction of the 150 kV lines by the German Consortium.

Two of the four Kaplan-type turbine runners, built at the Voith House in Germany, could not be shipped to Uruguay, and were installed in the Großraming dam, built with labor (227 prisoners) from the Tenberg concentration camp in Austria.

In addition to the five engineers who traveled to the United States to learn about hydroelectric plants, the continuity of the civil works was possible for the Uruguayan engineers and local workers hired under the administration regime directly by the RIONE. Official electricians and mechanics brought from the UTE, foremen and rural laborers, from all parts of the country, worked on the project, many of them illiterate. The anonymous heroes (the gauchos), despite the little theoretical knowledge they had, solved problems such as having a foundry workshop in Rincón del Bonete, or carrying out the assembly of bridge cranes without having a single assembly plan or diagram. Despite the total lack of adequate safety elements, in the entire construction period of the work, only four deaths were recorded due to work accidents, a figure that is maintained to this day in this type of works, with no deaths occurring in the flood of 1959, the renovation work of the plant, and more than 60 years of operation and maintenance of the same.

In January 1943, the manufacturing of the turbine and generator for Unit 2 was contracted in the USA, a machine that was most advanced at the time the German CONSAL Consortium abandoned the work. The RIONE also had to complete the civil works of the pillars R8, R9 and R10 on the left bank, the AR1 pillar on the right, the machine house, closure of temporary openings in the pillars U8 to U13, emergency generator location, side walls (the buffer bed), disassembly of cofferdams and cleaning, construction of the bridge pass, and diversion of the railway in Cardozo town.

The adaptations had to change the German standardization to English (used in the USA), the dimensions and dimensions in millimeters to inches, the output voltage of the generators was changed from 7 to 13.8 kV, the rotation speed from 136.4 to 125 RPM, the voltage of the high-voltage lines from 170 to 161 kV. The European network frequency of 50 Hz did not change to 60 Hz, given that 50 Hz was the network frequency adopted in Montevideo when the previous thermal plants and the new Calcagno plant were built. The ring of 31.5 kV underground cables in Montevideo, with 4 remote-controlled substations from a new Command Room located in the Batlle Central, which would become the System's Load Dispatch (before its transfer to Melilla with the construction of the Palmar Central and the 500 kV system).

The first easement for electrical wiring in Uruguay was established on June 7, 1889, by the contractor of the company "Luz Eléctrica"; Marcelino Díaz y García, in low and medium voltage lines, which had to fix their posts and measurements in the homes and roads of the city of Montevideo.

First Electrical Easement – ​​year 1889.

A note, dated June 7, 1889, addressed to the Political Chief and Chief of Police of Montevideo said; "The Electric Light contractor Don Marcelino Díaz y García has made this Board aware that some owners and tenants resist him when he tries to install the devices intended for the public lighting service in the buildings. He therefore requests that this Corporation provide him with the necessary assistance, in order to be able to comply with the commitment made on the matter."

"After hearing the direction of the branch, it has been resolved by the Board that I address you. Demanding the necessary assistance, in the interest that the City's lighting can be established, without unjustified opposition, since in the case of a matter related to security and public order, all properties are subject to legally supporting the easement."

"In this sense, I ask you to transmit your orders to the Police Commissioners, so that the public force is provided to the indicated contractor when required in order to overcome the difficulties encountered in the installation of cables, insulators and other electrical light devices."

Telegraphic Easements - year 1877.

The railway companies, like all those authorized to build telegraph lines, could use the easements established by the Decree Law of June 7, 1877, article 688 of the Rural Code for the placement of poles on private land and the passage of employees in charge of the conservation and repair of the lines, the companies being responsible for the damages that for such reasons will be caused to the encumbered private properties.

(SOURCE: Annals of the Universities A7 T9 delivery IV 1898).

Law of September 27, 1906.

This Law creates the new company “Usina Eléctrica de Montevideo”, replacing the old “Luz Eléctrica”, with the monopoly on the generation and distribution of public lighting, selling light and motive power to individuals, in the Department of Montevideo. For wiring, a regime of easements is established.

Servicios and 150 kV lines.

Decree Law No. 10 383, of February 13, 1943, determines the easements and compensation for damages, for the high tension lines between Rincón del Bonete and Montevideo, for the definitive occupation of the towers or masts, security in general and the works of laying the aerial cables. In Uruguay, the easement determines the prohibition of construction and forest plantations under the 150 kV transmission lines in a strip originally of 160 m in total, which was later lowered to 60 m by the Decree of December 27, 1956. Decree 534/976 dated 08/17/1976, which regulated the easements for the transmission lines of the Salto Grande works of 500 kV established an 80 m wide strip whose axis coincides with that of the line in question. Decree 174/969 dated 04/10/1969 established it, for several transmission lines at 30 kV and 60 kV voltage, at 30 m in total width, with an axis coinciding with that of the respective layout.

The laying of the first line began in July 1944, with the assembly of 780 towers, by engineer Víctor Campistrous and Rubén Dal Monte.

Construction of power lines

The first 150 kV high voltage power line in Uruguay was built between 1944 and 1945. Originally, the high voltage towers were to be manufactured in Germany. Because of the war they could not be delivered. After the war, they were confiscated by the Soviet Union and built near Tbilisi (Fig. 1). In their place, high voltage towers from the US were delivered (Fig. 2). In Montevideo, the lines are hosted in one system, further north in two separate systems.

• - Originally planned electric towers[2]​.

• - Electrical towers built[3]​.

On December 19, 1945, at the initiative of engineer Luis Giorgi as a tribute, he invited engineer Víctor Soudriers to start up Rincón del Bonete Unit 2 as tests, which had to remain in service on the 21st as an emergency, due to the failure of one of the machines at the Batlle Central in Montevideo. This first energization to Montevideo was carried out with a power outage for about 5 minutes, since synchronization or parallel was not carried out between Unit 2 and the Batlle Central machines.

The dam was officially inaugurated on December 26, 1945, by the President of the Republic Dr. Juan José Amézaga, and the Ministers of Public Works Tomás Berreta and Public Health Dr. Francisco Forteza, together with the mayors of Tacuarembó and Durazno, the president of the RIONE, the engineer Eduardo Terra Arocena") and the ambassador William Dawson") of the USA, in an event and subsequent lunch attended by some 2000 people. Also attending and speaking were Dr. Alberto Mañe (Colorado politician and supporter of Terra), Senator Ángel Cusano for the National Party, José Antuña and Senator Dr. César Charlone "César Charlone (politician)"), on behalf of the former ministers of Terra. Unit 1 was inaugurated on January 5, 1947, Unit 3 on October 25, 1948, and Unit 4 on December 24, 1948.

The Law of April 12, 1950 determined the cessation of the work of the RIONE (Technical and Financial Commission of the Hydroelectric Works of the Río Negro), making the works depend on the UTE (State Electric Power Plants and Telephones), and the personnel assimilated to it with similar hierarchies, or would be retired with the benefit of additional pay of 2 months per year worked in the RIONE. On May 2, 1950, the RIONE's assets and values ​​were delivered to UTE, leaving only the completion of some subsoil injections, lighting the dam, and fixing the town's roads.

The relocation of flooded populations when the dam reservoirs filled with water, an issue currently planned in the construction of large reservoirs, was not for Rincón del Bonete. This is the case of the town Cardozo (Uruguay) "Cardozo (Uruguay)") or Cardozo Grande, which was partly under water, another part isolated without land communication when the gigantic peninsula resulting from the artificial lake was formed, and its population dispersed (of about two thousand inhabitants before the construction of the dam, only a few dozen residents remain). The solution planned for that time was the expropriation of the entire town, based on the meager real estate value of the properties, with an individual payment to each resident for their relocation. This did not solve the problem since the money was not enough to cover the expenses of moving the residents to collect compensation to Montevideo, and the expenses of moving to a new location (rental or acquisition of a new home). These situations were not repeated, such as the case of the town Andresito (Uruguay) "Andresito (Uruguay)") flooded by the Palmar Dam reservoir, building a new town next to Route No. 3, and relocating all its inhabitants.

The Rincón del Bonete work was designed by Ludin already in 1933, in two stages for the crowning of the dam. In the First Stage, crowning of +84.30 m, for a normal operating level of the reservoir (without discharge) of +80.00 m; The downstream level would be between levels 52 and 53.60 m, and the threshold of the spillway at a level of +76.00 m. This First Stage was executed by the RIONE (1938..1950) for the dam in the section of intake gates of the four turbines, and in the spillway, but not in the right and left bank dams, which were executed at a crown level of +84.30 m.

In the Second Stage, which corresponded to the entry into service of the "Rincón de Baygorria" plant, the crest would be raised to a level of +86.90 m, and the operating level to a level of 83.00 m in order to recover the fall that was reduced as a result of the Baygorria backwater, which would raise the level of the Negro River in Paso de los Toros and downstream from Rincón del Bonete by about 2 meters in height. Also the threshold of the landfill would be raised according to the Ludin project to a height of +79.00 m, but this was not carried out by the RIONE, and until today the threshold is located at a height of +76.00 m.

The continuation of the Second Stage works was planned in 1954, by the Civil Engineering Office of Hydroelectric Works of UTE, with elevation of the riverbank dike to a level of +87.00 m. completed after the 1959 flood, in terms of increasing the elevation of the side dams, but the operation of the lake remained within the elevation range; 70.00..80.00 meters. The sections of the dam in the area of ​​the water intake and the spillway were initially built at a height of 43.30 meters above the deep foundation in the river bed, that is, a level of 86.90 m at the final level of the reservoir according to Adolf Ludin's project of 1933.

The non-optimal geological conditions of the dam's foundation soil led to the pillars being designed so that the compression of the ground was minimal. This was achieved with the Noetzli system), similar to that used in Río Salado in Mexico, a hollow wall and buttresses with solid round heads that transmit the pressure of the reservoir to the ground. The usual compressive stress on the ground of 8 kg/cm, for a vertical gravity dam, was lowered to 3 to 4 kg/cm uniformly distributed. In the abutments of the dam, right and left bank, the most extensive in the Department of Durazno, as the height is smaller, and the foundation rock far from the river bed is more solid, a gravity profile wall was used, more economical than the central pillars of the Noetzli type.

In October 1952, the Engineer Battalion No. 3 was awarded a field located on Lake Rincón del Bonete, known as “field 3”, located at the height of Arroyo Cardozo, which would be used to provide instruction and maintain livestock.

By Law No. 11 407, of March 30, 1950, the so-called RIONE (TECHNICAL AND FINANCIAL COMMISSION OF THE HYDROELECTRIC WORKS OF THE RÍO NEGRO) is dissolved. Article 2 deals; "The tasks of the Technical and Financial Commission of the Hydroelectric Works of the Río Negro (R.I.O.N.E.) are declared completed", Article 3; "All the works that were in charge of the R.I.O.N.E., in their current state, will immediately pass under the dependence of the General Administration of Electric Power Plants and State Telephones (U.T.E), in charge of their completion, as well as their exploitation and administration.",.

Construction control was carried out with a UTE office in Montevideo (Project Manager, 4 engineers, two public accountants, two engineering assistants and 3 administrative officials), and a work monitoring and control office at the dam (Construction Manager, 3 engineers, 8 construction controllers and two administrative officials). The renovation work on site began in November 1993, with the renovation of Unit 3 and the assembly of all the new auxiliary equipment being carried out during 1994. In 1995, Unit 4 was renovated, in 1996, Unit 1 and in 1997, Unit 2. For 3 years, two parallel plants practically coexisted, with two control rooms, two low voltage installations, some generating units renovated and others not renovated. All this was done only with the unavailability of one unit at a time for a total of 10 months; one month of disassembly, 8 months of assembly, one month of rehearsals. Following two months of the so-called semi-industrial test run, with the unit generating, without unavailability (loss of production). The old auxiliary facilities were dismantled in 1997, the old Command Room also went out of service that year.

At the request of the World Bank, who granted the loan to renovate the Central, a consulting firm was hired to support the project (1992 to 1994), and another to monitor the work (1994 to 1997). In the first, the services of the eminent engineer Roberto Maissonave, who was head of the Central for many years, and the engineer Siegmund Antmannn, who was previously director of Comipal, the organization that carried out the Palmar dam project (officially called “Constitución”), also on the Río Negro, were counted on. The construction consultancy was carried out by the English firm Merz and Mc Lellan, with a resident mechanical engineer, engineer Harry Rana, and a resident electrical engineer, engineer Anthony Beaumont.

The 150 kV high voltage power circuit breakers, original Westinghouse brand of the large oil volume type, were preserved until 2005, when they were replaced by three-phase dead tank type circuit breakers (work carried out by the Plant's own personnel), supplied by the manufacturer Areva in Charleroi USA (later Alstom T&D). In 2006, the Wizcon SCADA system and its Siemens remote control units (RTUs) were replaced with new national technology equipment, the Mirage SCADA system and remote controls from the manufacturer Controles S.A. from Uruguay. In 2009, the manufacturer of the new generators, Alstom France, was contracted to repair points damaged by the corona effect between high voltage bars of different phases, in the 4 generators.

In March 1935, the Engineer Battalion No. 3 (Uruguay) moved from Rivera to its new headquarters in Paso de los Toros. He passes to this town, occupying the Barracks that the Infantry Battalion No.10 will hand over. Part of the premises, which still remain in their current headquarters, were the warehouses of the first and most important industry that Paso de los Toros has had: the saladeril (salting factory) founded in 1884 by Don Juan André and Don Valentín Piñeyrúa. Among the many tasks assigned to Battalion No. 3, the important one for the history of the dam was the construction of the Rincón del Bonete landing strip (parallel to the road, located on the left hand side reaching Rincón del Bonete and before reaching the gap), which in the 1959 flood allowed the establishment of an air bridge with helicopters with Rincón del Bonete and with Paso de los Toros with civil aircraft, evacuating the dam personnel who remained there to dismantle the generating turbines before the waters covered them.

The initial cost of the work was financed with the issuance of public debt for 48:$ (48 million pesos), law of February 1934. The total final amount of the budget for the work reached close to 50:$ (millions of pesos), almost 1/6 of the GDP (gross domestic product of the time), composed of; 41:$ including interest to be paid to the German consortium, plus 5:$ in expropriations, 1.4:$ for the waterproofing of the subsoil, $740,000 in administration expenses, $300,000 in housing, the railway to Paso de los Toros $130,650, and $400,000 for the diversion of the railway line in Cardozo town.

The contract for the construction of the dam, between the German Consortium and the UTE, was signed on April 15, 1937, establishing that the work should be completed on April 30, 1942. [1] The contract established the total price (the subsoil waterproofing injections were in a separate contract) of the works; $17,744,776.67 (seventeen million Uruguayan pesos), plus £2,344,871 (two million British pounds). By way of comparison, the Grand Coulee Dam, built in its first stage between 1934 and 1943, and about seven times the size of Rincón del Bonete; cost $163 (one hundred and sixty-three million dollars). The payments necessary for the completion of the work, after the events caused by the Second World War, raised the total cost of the work to 107:$ (107 million pesos, equivalent to the cost of 50,000 automobiles). The monitoring and receipt of materials or equipment in the factory would be by Bureau Veritas. The contract, as usual, established multiple amendments to the bidding document, negotiated between UTE and the German consortium. The German generators would be; two part of the house Siemens Schuckerwerke-Gesellschaft A.G. (S.S.W.), and two others by Allgemeine Elektricitats-Gesellschaft A.G. (A.E.G.).

Today it seems difficult to believe that the dam was built with German Portland cement and not with national cement, but in 1937, Uruguay did not have factories capable of producing the volumes and quality of cement that such a work required. The German cement brought into the country would be tested on samples of each shipment, to be carried out at the Materials Testing Institute of the Faculty of Engineering (University of the Republic). The price of German Portland cement was 17 Uruguayan pesos per ton.

On May 18, 1937, the foundation stone was placed on 18 de Julio Avenue, almost Sarandí, in the flowerbed of the avenue in front of the Paso de los Toros plaza. A crowd of 12,000 people, many of them UTE officials, was transported by train from Montevideo to Paso de los Toros, to a party where food was distributed to the needy population, military bands, a barbecue with leather in the Municipal Park, and a flight of Army planes (the Air Force did not yet exist), and PLUNA.

A day before, the 4 new Brill model 60 motorcars (no. 129, 130, 131 and 132) had been expressly sent by rail from Montevideo, coupled together and completely empty, arriving at their destination, at the Paso de los Toros station in the department of Tacuarembó, in the afternoon, the objective of their trip being to exhibit them to the community. The Brill cars caused great admiration, they spent the night at the station and remained detained until the next day, when two trains arrived with the procession. The second of them, towed by the Class S locomotive No. 144, was the one who brought the wife of President Gabriel Terra, since he, fearing an attack on his life, could not attend the event. They had already tried to assassinate him in 1935 at a meeting in Maroñas that he attended with the Brazilian president Getulio Vargas. President Terra sent a one and a half hour speech that was broadcast over a network of speakers, which was followed by the singing of the national anthem and words by the Minister of Public Works Dr. Martín Echegoyen, the German Ambassador to Uruguay Hans Moraht and the representative of the German Consortium Dr. Karl Stoop.

To close, two telegrams were read between the presidents of Germany and Uruguay, on the occasion of the laying of the foundation stone that began the work:

"Berlin, May 17, 1937. Your Excellency President of the Eastern Republic of Uruguay, Dr. Gabriel Terra. On the success of the monumental work of the Río Negro, begun at the initiative of your government, I express to your Excellency my most sincere congratulations. Adolfo Hitler, Chancellor of the Third Reich."

And this answer:

"Montevideo, May 17, 1937. To Your Excellency Mr. Adolfo Hitler. Führer Und Reichkanzler. Berlin. I thank Your Excellency for your cordial congratulations on the occasion of the initiation of the hydroelectric works on the Río Negro. I trust in their success because they will be carried out by German technicians of great scientific reputation and honorable tradition. Our country will never forget everything that Your Excellency's government has done to facilitate the execution of the contract. And I am sure that through these works, whose initial impulse is celebrated today by the Uruguayan people, our two countries will feel more linked every day in their firm friendship. Gabriel Terra, President of the Republic."

On September 28, 1938, at the request of the new elected President, General Architect Alfredo Baldomir, as the “Honorary Commission for Financial Supervision of the Works” (from April 12, 1937) could not adequately fulfill its function as controller, which overlapped with the controller of UTE, the Technical and Financial Commission of the Hydroelectric Works of the Río Negro was created, better known as “The RIONE.”

Law No. 9786; Article 1: The Technical and Financial Commission for the hydroelectric works of the Negro River is created. Its relations with the Executive Branch will be through the Ministry of Public Works, without prejudice to the intervention of the Ministry of Finance in the relevant matters. It will have an honorary character, it will enjoy legal status and its functions will last until the completion of the tasks assigned to it. It will be made up of a President and four members, both appointed by the Executive Branch, one of them as a delegate of the Ministry of Public Works and the other of the Treasury; and will also be integrated as ex officio members with the Presidents of the Bank of the Republic and the U.T.E. and the Directors of the Geological and Hydroelectric Studies Institute.

The commission would be directly dependent on the Hydroelectric Studies Commission, headed by Eng. Víctor Soudriers and headed by the Minister of Public Works, with legal status, and until the end of the work. "You should adjust your budget to the $754,000 planned for the Construction Management").

In August 1937, the assembly of the warehouses, layout of the streets, homes, squares, sports fields, social club, canteen, dining room and school began. Surface covered by constructions adding; 5450 m² in homes and 3230 m² in warehouses.

In particular the homes of CONSAL staff and RIONE construction controllers; 2 temporary wooden bedrooms for CONSAL, 1 kitchen dining room for CONSAL, 8 dormitory sheds for 88 workers each, one for sub-foremen and married officers, 5 series of toilet services, 2 series of 8 homes for foremen, 2 series of 4 homes for engineers and superintendents of the RIONE, series of 8 homes for sub-foremen and married officers of CONSAL, premises for the administrative offices of CONSAL and RIONE construction control, sanitation network, drinking water and low voltage electricity, layout, street arrangement, 200 m³ raw water tank, 100 m³ drinking water tank. Urban planning would be in charge of Architect Julio Vilamajó.

In November 1937, construction of the 11 km of railway between Rincón del Bonete and Paso de los Toros began. The work ended in January 1938, during which time the material arriving from abroad for the work was accumulated at the Paso de los Toros railway station. The 14 km of the road between Bonete and Paso de los Toros, with streams without bridges (El Sauce, Las Nutrias, Sauce de Albuquerque), did not allow passage other than carts pulled by oxen.

The aggregates (stones and gravel) for the work were extracted from the area adjacent to the work, with a crushing plant with 3 breaking machines of 80m3 per hour, washing machines, vibrating screens and cement mixers. The sand was extracted from the river and stored in silos. The movement of aggregates and concrete was carried out in narrow gauge trains and wagons, Via Decauville of 600 mm, which ran through the work, or by means of a cable rail from one bank to the other.

In total the equipment of the quarry was made up of: 1 excavator shovel, 2 160 HP locomotives, 2 percussion drills, 5 pneumatic hammers, 1 dewatering pump. Between August 1, 1938 and November 30, 1939, they were extracted from the quarry; 43,208 m³ of material, of which 37,374 m³ went to the crushing plant and 5,834 m³ were rejected.

In December 1937, work began on the foundations for the crushing facility, which was completed and tested in July 1938. The crushing plant includes: a primary breaker with a performance of 80-100 m/hour, two secondary crushers with a performance of 80 m/hour, two washing machines with a diameter of 2 meters and a drum length of 7 meters, two vibrating screens, in four sections. staggered that separate the material into grain groups of 0-7; 7-15 and 17-60 mm.

For the preparation of intermediate granulated material there are three fine material crushers with a total capacity of 40 m³/hour. It also includes the river sand separation facility with a performance of 50 m³/hour, main tanks, and aggregate silos with their dosing devices at the bottom of these, and the conveyor belt systems necessary for the entire facility.

It consisted of; the cement tank, the endless conveyor for it, the compensating silo directly on the automatic scale that weighs the cement according to the established proportions. The aggregated materials are transported from the already provided silos to the mixer by conveyor belts. Two mixers with a capacity of 1500 liters each.

A cable rail transports the materials to the left bank (Durazno side) of the river, where silos accumulate the aggregates.

About 1,000 workers and numerous machinery were used for concreting (5 Wolf "Crane (machine)" cranes, 4 narrow gauge (600 mm) diesel locomotives). The total reinforced concrete of the dam is 350,000 m³, using 77,000 tons of cement and 60,000 tons of iron.

The D2 "M" type concretes with 280 kg of cement per m³ were tested for compression in specimens; 20 x 20 x 20 cm cubes, resulting in a compression breaking load of 150.7 kg/cm² (average of 199 tests) after 7 days of setting, and a breaking load of 252.4 kg/cm² (average of 192 tests) after 28 days of setting.

The flexural tensile tests on unreinforced beams measuring 15 x 10 x 70 cm resulted in an average breaking load of 37.4 kg/cm² (average of 54 tests) at 7 days of setting, and a breaking load of 51.5 kg/cm² (average of 127 tests) at 28 days of setting.

The permeability tests were carried out on a 10 cm thick plate with a surface area of ​​200 cm². The results were for; 1 atm of pressure for 24 hours: they permeated 0 cm³ of water (average over 115 tests), at 3 atm of pressure for 24 hours: they permeated 1.6 cm³ (over 115 tests), at 7 atm of pressure for 12 hours: they permeated 12.1 cm³ (over 109 tests).

The total number of railway tracks in the workshop and work in the cofferdam ditches 1 and 2 included: 1000 linear meters of normal or international gauge of 1435 mm, 7600 meters of gauge of 900 mm (3', three feet wide), 2000 meters of narrow Decauville gauge of 600 mm (1' 11"), and the cable rail to transfer materials to the left bank. (Peach).

The railway between Paso de los Toros and Rincón del Bonete entered service on January 30, 1938, transporting materials previously stored at the Paso de los Toros train station. Passenger service was inaugurated in May 1938.

On January 17, 1938, construction of the service railway bridge that crosses the Río Negro downstream of the works begins. Construction is interrupted by the flood from April 21 to May 26, 1938, and a second flood from June 27 to September 7, 1938. Construction ends on June 13, 1939. The bridge has a length of 300 meters, in 25 sections of 12 meters each.

It is currently known as the “broken bridge” after the 1959 flood swept away its beams and pillars.

The so-called temporary electric power generation plant includes the building, the cooling water and diesel fuel oil tank, and the electrical installations for a total of 2,500 HP. The engine-generator groups consisted of; 1 auxiliary group of 80 KVA, 2 diesel generator groups of 520 HP each, 2 groups of 500 HP each. A fifth group of 500 HP is installed in 1939. As an example, the energy generated between May 1, 1938 to November 30, 1939 was; 4,442,225 kWh.

The water treatment plant, for the purification of the raw water of the Negro River by flocculation and decantation by application of alumina sulfate, came into service on August 16, 1938. Previously, in 1937, the service water, for the work and the drinking population, still non-potable water, was provided from a temporary water intake, upstream of the cofferdam of Ditch No. 1, passing it through a filter of sand and chlorinator with sodium hypochlorite.

The start of the first cofferdam, Foundation Trench No. 1 (right bank, Tacuarembo side), began to be assembled on September 16, 1937. The two starts of the cofferdam are composed of two rockfills in a concrete core with a total length of 68 meters. On November 6, the placement of the 4,006 steel sheet piles, in 37 round cells, and the filling of clay sand begins. Metal steel sheet piles from Bethlehem type SP 6 and FT 60, lengths 11.0 and 12.2 meters. Ditch No. 1 was completed on February 14, 1938, with a perimeter of 537 meters that enclosed an area of ​​30,000 m². The draining was carried out between February 17 and 19, with 3 160 HP (horsepower) steam locomotives used to move the pumps to first empty and then bilge the water trapped by the cofferdam and subsequent leaks. The openings of Trench No. 2 (left bank, Durazno side) were built in openings 57 meters long. A third cofferdam, Trench No. 1a, was necessary for the excavation of the lower channel, this downstream and outside of Trench No. 1 described above. This auxiliary cofferdam was built as an embankment of material from the same excavation, between March 26 and April 28, 1939, with a volume of 1278 m³ of material.

On October 22, 1937, excavation for the dike began on the right bank outside Trench No. 1. In March 1939, excavation work began inside the ditch itself, which was completed in December of the same year. The total excavated for the dike, buffer bed and guard wall within Trench No. 1 reaches 2,406 m² of loose soil and 60,960 m³ of rock, including additional excavation to deepen the foundation of the landfill buttresses. In the dike area, within Trench No. 1, the volume of rock excavated was 38,300 m³.

On the left bank, Trench No. 2, the loose soil excavation work began on May 24, 1939 at the track and assembly site for the excavators, with 63,678 m³ of loose soil and 1,562 m³ of rock having been extracted by November 30. In the lower channel of the plant, 65,898 m³ of rock were excavated, of which 44,495 m³ were outside the cofferdam of Trench No. 1. Of the rock table, 28,847 m³ were destined for the crushing plant for use in concrete.

The excavation equipment within Trench No. 1 consisted of: 2 Demag shovels of 150 HP and 1,350 m³ capacity, 1 Demag shovel of 150 HP and 1,600 m³ capacity, 1 Demag shovel of 75 HP and 1,000 m³ capacity, 1 M&K shovel of 160 HP with 2,200 m³ capacity, 1 shovel O&K with a 750 liter grapple, 1 O&K shovel with a 300 liter grapple, 1 5 ton pile hammer powered by a compressed air pile driver, 3 locomotives of 160 HP, 3 locomotives of 200 HP. On the left bank, Trench No. 2, the 150 HP-1,350 m³ Demag shovel, the 2 160 HP locomotives and their respective dump cars, 1 52 HP compressor and drilling machines were used. In the area of ​​Trench No. 1, 3 excavator shovels, 3 160 HP locomotives and their dump cars were used.

On August 29, 1939, the concreting of the pump well with 2,406 m³ began, the Assembly Room continued up to a level of +65.00m with 850 m³ of concrete, and the infrastructure of the Machine Room; 29,246 m³. Concreting began on the buffer bed on September 22, 1938 with 3,400 m³, continued on the guard walls with 4,686 m³, and foundation of the buttress with 11,737 m³ and elevation works. Until November 30, 1938, the round-headed buttresses carried 41,749 m³, the water intake structure; 6015 m³, the landfill folder; 523 m³ and buttress foundations 673 m³. The concreting of the pillars of the 170 KV High Voltage Station began on February 25, 1939, with 5,680 m³ of concrete used in the foundation and pillars, a volume of 480 m³ for the slab and beams of the platform of the esplanade adjacent to the power plant.

The concrete placement equipment used consists of 4 60 cm gauge diesel locomotives with special tacho cars, 5 Wolf cranes, 1 conveyor bridge, discharge chutes and vibrators.

The foundations of the dam, despite being within the basaltic region, were reinforced with waterproofing curtains; numerous injections of cement (1500 tons) and chemicals (198 tons of sodium silicate and 73 tons of calcium chloride), into the altered or porous basalt layers. In accordance with the contract of April 15, 1937, a second contract had to be signed to resolve the problems and injections of the subsoil of the foundation of the dam, in order to compact it and waterproof it as much as was technically possible.

Achieving a completely impermeable curtain under the dike was assumed to be something impossible to achieve, which is why a degree of permeability of 1 liter per linear meter per minute was defined, under a water pressure of 4 atmospheres, a pressure measured in a vertical section 4 meters high.

The 9,850 drillings with a diameter of 60 mm (2-3/8 inches) were made dry, inside the trenches and their cofferdams. The start of each drilling using 100mm diameter steel pipes, from which the drilling machines reached a depth of +25.00 m underground, about 25 or 30 meters below the bed of the Río Negro, all along the dam in 3 parallel planes, the drillings separated by 4 meters from each other, and alternating in a staggered pattern. 9 Ingersoll Rand drilling machines, model COROC MD2, were used, and the injections were carried out with 5 Svenska Diamant Borrings A.B. equipment powered by compressed air. Starting before the signing of the drilling and injection contract, in September 1938.

The injections were carried out in 3 stages, at different injection pressures; the first stage at 7 atm. pressure and capacity of 3 liters per minute of cement slurry 1686 tons and chemicals (sodium silicate 198 tons and calcium chloride 73 tons), slurries with a density of 1.8 kg/L, the second stage at 11 atm., the third stage at 15 atm. and the fourth stage at 20 atm. Cement quantities of 2000 kg in stage 1 and 2, and decreasing to tens of kg of slurry; cement dissolved in water. Before and after the final stage, the hydraulic test was carried out at 4.5 atm. of pressure with water, re-drilling a few hours after the injection has been carried out. The overall and average results of all injections were highly favorable, reaching water permeability values ​​of 5 liters per minute per linear meter applying a pressure of 10 atmospheres.

In the scenario of the Second World War, Hitler invades Czechoslovakia on September 30, 1938, which triggers actions due to the imminent stoppage of the Rincón del Bonete construction work. On May 25, 1939, a modification of the Contract was signed between Uruguay and Germany, modifying the payment method provided for on April 15, 1937, and providing for the suspension of work in the event of bankruptcy, insolvency, impossibility of delivering the material in Montevideo, machines and parts, or due to war affecting Germany. In the event of interruption of the work, the return of the pledge as collateral for the clause would be carried out by the German Transatlantic Bank (Deutsche Überseeische Bank). the Montevideo branch. In August 1939, delays in the manufacture of "alternators" in Germany were evident, due to the lack of copper, which could only be acquired by Germany from the United States of America or Canada.

On September 1, the German Invasion of Poland in 1939 began. The J.M. equipment Voith of turbine No. 1; ring of sleepers, spiral box and the support of the A.E.G. generator, are detained in the port of Vigo Spain, awaiting procedures with the Allies to authorize their shipment to South America and Uruguay. Downstream closure boards, upstream closure cofferdams, and two of the four intake roller gates are stopped in Italian ports.

On December 17, 1939, in the so-called Battle of the Río de la Plata, three English warships inflicted serious damage on the German battleship Graf Spee, forcing it to be sunk by its captain near the port of Montevideo. From that fact, it became impossible to ship the electromechanical parts (turbines and generators) from Germany, and to pay for them with merchandise or cash shipments from Uruguay to Germany, even using merchant ships from or to neutral countries"), and between neutral ports (such as those in Spain or Portugal).

In 1941 the British ambassador to Uruguay Sir Ralph Skrine Stevenson; informs the Uruguayan government that the Ministry of War of its country would authorize these parts of the turbines from Germany, which thanks to merchant ships flagged by neutral countries were already in the ports of Santos and Rio de Janeiro in Brazil, and Valparaíso in Chile. This was on the condition that Uruguay did not issue payments for the works that arrived in Germany, and that the remaining orders for supplies of German equipment were cancelled. So the engineer Luis Giorgi begins the steps to acquire equipment in England first; Casa Vikers for the turbines, and English Electric for the generators. Finally, in 1942, the agreement was finalized with the government and the EXIM ("Export-Import Bank) of the United States.

First on a personal initiative, and later as state negotiations, Luis Giorgi began negotiations to purchase electromechanical equipment in the United States of America. The entry into war of the United States with the powers of the Rome-Berlin-Tokyo Axis, after the attack on Pearl Harbor, conditioned Uruguay to break off negotiations with the German consortium. The executive accepted the terms, setting the date of July 1, 1942 for the end of the contract with CONSAL, or an earlier date if the equipment was supplied from the United States. The transaction would be completed with the opening of the letter of credit before the Export and Import Bank, for 4: USD (4 million dollars) for a first generator and transmission line, and 8: USD (eight million dollars) for the remaining generating sets and second transmission line.

Three important floods exceeded 5,000 m³/s in 1941, floods only previously surpassed by the flood of 5,400 m/s in September-October-November 1918, a flood of 5,100 m³/s in 1925, and the flood of 8,300 m³/s in 1888 (historic for reaching the railroad bridge in Paso de los Toros). (elevation +62.43 m on the rails).

The first flood was in the months of February and March 1941, the second in April-May-June and the third in July-August-September 1941, destroying the work on the cofferdam and civil works in Trench No. 2 on the left bank (Department of Durazno side). The 1937 contract anticipated the flooding of the Río Negro up to a level of 60.60m upstream of the work and 59.50m downstream of the work. From those heights, it would be considered a flood in a "force majeure" situation.

On December 9, 1941, Uruguay prohibited trade and transfers of funds with Germany, Italy and Japan. On January 25, 1942, Uruguay broke diplomatic relations with Germany. On May 7, 1942, the Contract with CONSAL was terminated, by Decree of the President of the Republic, General Architect Alfredo Baldomir. Consequently, in July 1942, 95 German technicians and about 20 families left the work.

At the time of termination of the Contract with CONSAL, the dam was almost completed, the pressure tubes in the four turbines, the intake gates and their servomotors, the pump room thereof, the intake grates, the spiral casings, the rings and predistributors, the discharge suction tubes and their service closures, the upstream sieve cleaning crane and the downstream service crane, the civil works of the command house and offices, and the turbine room. No work had been done on the construction of the 150 kV lines by the German Consortium.

Two of the four Kaplan-type turbine runners, built at the Voith House in Germany, could not be shipped to Uruguay, and were installed in the Großraming dam, built with labor (227 prisoners) from the Tenberg concentration camp in Austria.

In addition to the five engineers who traveled to the United States to learn about hydroelectric plants, the continuity of the civil works was possible for the Uruguayan engineers and local workers hired under the administration regime directly by the RIONE. Official electricians and mechanics brought from the UTE, foremen and rural laborers, from all parts of the country, worked on the project, many of them illiterate. The anonymous heroes (the gauchos), despite the little theoretical knowledge they had, solved problems such as having a foundry workshop in Rincón del Bonete, or carrying out the assembly of bridge cranes without having a single assembly plan or diagram. Despite the total lack of adequate safety elements, in the entire construction period of the work, only four deaths were recorded due to work accidents, a figure that is maintained to this day in this type of works, with no deaths occurring in the flood of 1959, the renovation work of the plant, and more than 60 years of operation and maintenance of the same.

In January 1943, the manufacturing of the turbine and generator for Unit 2 was contracted in the USA, a machine that was most advanced at the time the German CONSAL Consortium abandoned the work. The RIONE also had to complete the civil works of the pillars R8, R9 and R10 on the left bank, the AR1 pillar on the right, the machine house, closure of temporary openings in the pillars U8 to U13, emergency generator location, side walls (the buffer bed), disassembly of cofferdams and cleaning, construction of the bridge pass, and diversion of the railway in Cardozo town.

The adaptations had to change the German standardization to English (used in the USA), the dimensions and dimensions in millimeters to inches, the output voltage of the generators was changed from 7 to 13.8 kV, the rotation speed from 136.4 to 125 RPM, the voltage of the high-voltage lines from 170 to 161 kV. The European network frequency of 50 Hz did not change to 60 Hz, given that 50 Hz was the network frequency adopted in Montevideo when the previous thermal plants and the new Calcagno plant were built. The ring of 31.5 kV underground cables in Montevideo, with 4 remote-controlled substations from a new Command Room located in the Batlle Central, which would become the System's Load Dispatch (before its transfer to Melilla with the construction of the Palmar Central and the 500 kV system).

The first easement for electrical wiring in Uruguay was established on June 7, 1889, by the contractor of the company "Luz Eléctrica"; Marcelino Díaz y García, in low and medium voltage lines, which had to fix their posts and measurements in the homes and roads of the city of Montevideo.

First Electrical Easement – ​​year 1889.

A note, dated June 7, 1889, addressed to the Political Chief and Chief of Police of Montevideo said; "The Electric Light contractor Don Marcelino Díaz y García has made this Board aware that some owners and tenants resist him when he tries to install the devices intended for the public lighting service in the buildings. He therefore requests that this Corporation provide him with the necessary assistance, in order to be able to comply with the commitment made on the matter."

"After hearing the direction of the branch, it has been resolved by the Board that I address you. Demanding the necessary assistance, in the interest that the City's lighting can be established, without unjustified opposition, since in the case of a matter related to security and public order, all properties are subject to legally supporting the easement."

"In this sense, I ask you to transmit your orders to the Police Commissioners, so that the public force is provided to the indicated contractor when required in order to overcome the difficulties encountered in the installation of cables, insulators and other electrical light devices."

Telegraphic Easements - year 1877.

The railway companies, like all those authorized to build telegraph lines, could use the easements established by the Decree Law of June 7, 1877, article 688 of the Rural Code for the placement of poles on private land and the passage of employees in charge of the conservation and repair of the lines, the companies being responsible for the damages that for such reasons will be caused to the encumbered private properties.

(SOURCE: Annals of the Universities A7 T9 delivery IV 1898).

Law of September 27, 1906.

This Law creates the new company “Usina Eléctrica de Montevideo”, replacing the old “Luz Eléctrica”, with the monopoly on the generation and distribution of public lighting, selling light and motive power to individuals, in the Department of Montevideo. For wiring, a regime of easements is established.

Servicios and 150 kV lines.

Decree Law No. 10 383, of February 13, 1943, determines the easements and compensation for damages, for the high tension lines between Rincón del Bonete and Montevideo, for the definitive occupation of the towers or masts, security in general and the works of laying the aerial cables. In Uruguay, the easement determines the prohibition of construction and forest plantations under the 150 kV transmission lines in a strip originally of 160 m in total, which was later lowered to 60 m by the Decree of December 27, 1956. Decree 534/976 dated 08/17/1976, which regulated the easements for the transmission lines of the Salto Grande works of 500 kV established an 80 m wide strip whose axis coincides with that of the line in question. Decree 174/969 dated 04/10/1969 established it, for several transmission lines at 30 kV and 60 kV voltage, at 30 m in total width, with an axis coinciding with that of the respective layout.

The laying of the first line began in July 1944, with the assembly of 780 towers, by engineer Víctor Campistrous and Rubén Dal Monte.

Construction of power lines

The first 150 kV high voltage power line in Uruguay was built between 1944 and 1945. Originally, the high voltage towers were to be manufactured in Germany. Because of the war they could not be delivered. After the war, they were confiscated by the Soviet Union and built near Tbilisi (Fig. 1). In their place, high voltage towers from the US were delivered (Fig. 2). In Montevideo, the lines are hosted in one system, further north in two separate systems.

• - Originally planned electric towers[2]​.

• - Electrical towers built[3]​.

On December 19, 1945, at the initiative of engineer Luis Giorgi as a tribute, he invited engineer Víctor Soudriers to start up Rincón del Bonete Unit 2 as tests, which had to remain in service on the 21st as an emergency, due to the failure of one of the machines at the Batlle Central in Montevideo. This first energization to Montevideo was carried out with a power outage for about 5 minutes, since synchronization or parallel was not carried out between Unit 2 and the Batlle Central machines.

The dam was officially inaugurated on December 26, 1945, by the President of the Republic Dr. Juan José Amézaga, and the Ministers of Public Works Tomás Berreta and Public Health Dr. Francisco Forteza, together with the mayors of Tacuarembó and Durazno, the president of the RIONE, the engineer Eduardo Terra Arocena") and the ambassador William Dawson") of the USA, in an event and subsequent lunch attended by some 2000 people. Also attending and speaking were Dr. Alberto Mañe (Colorado politician and supporter of Terra), Senator Ángel Cusano for the National Party, José Antuña and Senator Dr. César Charlone "César Charlone (politician)"), on behalf of the former ministers of Terra. Unit 1 was inaugurated on January 5, 1947, Unit 3 on October 25, 1948, and Unit 4 on December 24, 1948.

The Law of April 12, 1950 determined the cessation of the work of the RIONE (Technical and Financial Commission of the Hydroelectric Works of the Río Negro), making the works depend on the UTE (State Electric Power Plants and Telephones), and the personnel assimilated to it with similar hierarchies, or would be retired with the benefit of additional pay of 2 months per year worked in the RIONE. On May 2, 1950, the RIONE's assets and values ​​were delivered to UTE, leaving only the completion of some subsoil injections, lighting the dam, and fixing the town's roads.

The relocation of flooded populations when the dam reservoirs filled with water, an issue currently planned in the construction of large reservoirs, was not for Rincón del Bonete. This is the case of the town Cardozo (Uruguay) "Cardozo (Uruguay)") or Cardozo Grande, which was partly under water, another part isolated without land communication when the gigantic peninsula resulting from the artificial lake was formed, and its population dispersed (of about two thousand inhabitants before the construction of the dam, only a few dozen residents remain). The solution planned for that time was the expropriation of the entire town, based on the meager real estate value of the properties, with an individual payment to each resident for their relocation. This did not solve the problem since the money was not enough to cover the expenses of moving the residents to collect compensation to Montevideo, and the expenses of moving to a new location (rental or acquisition of a new home). These situations were not repeated, such as the case of the town Andresito (Uruguay) "Andresito (Uruguay)") flooded by the Palmar Dam reservoir, building a new town next to Route No. 3, and relocating all its inhabitants.

The Rincón del Bonete work was designed by Ludin already in 1933, in two stages for the crowning of the dam. In the First Stage, crowning of +84.30 m, for a normal operating level of the reservoir (without discharge) of +80.00 m; The downstream level would be between levels 52 and 53.60 m, and the threshold of the spillway at a level of +76.00 m. This First Stage was executed by the RIONE (1938..1950) for the dam in the section of intake gates of the four turbines, and in the spillway, but not in the right and left bank dams, which were executed at a crown level of +84.30 m.

In the Second Stage, which corresponded to the entry into service of the "Rincón de Baygorria" plant, the crest would be raised to a level of +86.90 m, and the operating level to a level of 83.00 m in order to recover the fall that was reduced as a result of the Baygorria backwater, which would raise the level of the Negro River in Paso de los Toros and downstream from Rincón del Bonete by about 2 meters in height. Also the threshold of the landfill would be raised according to the Ludin project to a height of +79.00 m, but this was not carried out by the RIONE, and until today the threshold is located at a height of +76.00 m.

The continuation of the Second Stage works was planned in 1954, by the Civil Engineering Office of Hydroelectric Works of UTE, with elevation of the riverbank dike to a level of +87.00 m. completed after the 1959 flood, in terms of increasing the elevation of the side dams, but the operation of the lake remained within the elevation range; 70.00..80.00 meters. The sections of the dam in the area of ​​the water intake and the spillway were initially built at a height of 43.30 meters above the deep foundation in the river bed, that is, a level of 86.90 m at the final level of the reservoir according to Adolf Ludin's project of 1933.

The non-optimal geological conditions of the dam's foundation soil led to the pillars being designed so that the compression of the ground was minimal. This was achieved with the Noetzli system), similar to that used in Río Salado in Mexico, a hollow wall and buttresses with solid round heads that transmit the pressure of the reservoir to the ground. The usual compressive stress on the ground of 8 kg/cm, for a vertical gravity dam, was lowered to 3 to 4 kg/cm uniformly distributed. In the abutments of the dam, right and left bank, the most extensive in the Department of Durazno, as the height is smaller, and the foundation rock far from the river bed is more solid, a gravity profile wall was used, more economical than the central pillars of the Noetzli type.

In October 1952, the Engineer Battalion No. 3 was awarded a field located on Lake Rincón del Bonete, known as “field 3”, located at the height of Arroyo Cardozo, which would be used to provide instruction and maintain livestock.

By Law No. 11 407, of March 30, 1950, the so-called RIONE (TECHNICAL AND FINANCIAL COMMISSION OF THE HYDROELECTRIC WORKS OF THE RÍO NEGRO) is dissolved. Article 2 deals; "The tasks of the Technical and Financial Commission of the Hydroelectric Works of the Río Negro (R.I.O.N.E.) are declared completed", Article 3; "All the works that were in charge of the R.I.O.N.E., in their current state, will immediately pass under the dependence of the General Administration of Electric Power Plants and State Telephones (U.T.E), in charge of their completion, as well as their exploitation and administration.",.

Construction control was carried out with a UTE office in Montevideo (Project Manager, 4 engineers, two public accountants, two engineering assistants and 3 administrative officials), and a work monitoring and control office at the dam (Construction Manager, 3 engineers, 8 construction controllers and two administrative officials). The renovation work on site began in November 1993, with the renovation of Unit 3 and the assembly of all the new auxiliary equipment being carried out during 1994. In 1995, Unit 4 was renovated, in 1996, Unit 1 and in 1997, Unit 2. For 3 years, two parallel plants practically coexisted, with two control rooms, two low voltage installations, some generating units renovated and others not renovated. All this was done only with the unavailability of one unit at a time for a total of 10 months; one month of disassembly, 8 months of assembly, one month of rehearsals. Following two months of the so-called semi-industrial test run, with the unit generating, without unavailability (loss of production). The old auxiliary facilities were dismantled in 1997, the old Command Room also went out of service that year.

At the request of the World Bank, who granted the loan to renovate the Central, a consulting firm was hired to support the project (1992 to 1994), and another to monitor the work (1994 to 1997). In the first, the services of the eminent engineer Roberto Maissonave, who was head of the Central for many years, and the engineer Siegmund Antmannn, who was previously director of Comipal, the organization that carried out the Palmar dam project (officially called “Constitución”), also on the Río Negro, were counted on. The construction consultancy was carried out by the English firm Merz and Mc Lellan, with a resident mechanical engineer, engineer Harry Rana, and a resident electrical engineer, engineer Anthony Beaumont.

The 150 kV high voltage power circuit breakers, original Westinghouse brand of the large oil volume type, were preserved until 2005, when they were replaced by three-phase dead tank type circuit breakers (work carried out by the Plant's own personnel), supplied by the manufacturer Areva in Charleroi USA (later Alstom T&D). In 2006, the Wizcon SCADA system and its Siemens remote control units (RTUs) were replaced with new national technology equipment, the Mirage SCADA system and remote controls from the manufacturer Controles S.A. from Uruguay. In 2009, the manufacturer of the new generators, Alstom France, was contracted to repair points damaged by the corona effect between high voltage bars of different phases, in the 4 generators.