| Porce III Dam | |
| Name Official: | Presa Porce III |
| Location Map: | Colombia |
| Coordinates: | 6.9386°N -75.1386°W |
| Country: | Colombia |
| Status: | O |
| Construction Began: | 2004 |
| Opening: | 2011 |
| Owner: | Empresas Publicas de Medellin (EPM) |
| Dam Type: | Embankment, concrete-face rock-fill |
| Dam Height: | 151m (495feet) |
| Dam Length: | 426m (1,398feet) |
| Dam Width Crest: | 80NaN0 |
| Dam Width Base: | 400m (1,300feet) |
| Dam Volume: | 4155000m2 |
| Dam Crosses: | Porce River |
| Spillway Capacity: | 10850m3/s |
| Res Capacity Total: | 170e6m3 |
| Res Capacity Active: | 127e6m3 |
| Res Catchment: | 3756km2 |
| Res Surface: | 4.6km2 |
| Plant Operator: | EPM |
| Plant Commission: | 2010-2011 |
| Plant Turbines: | 4 x 172MW Francis-type |
| Plant Capacity: | 660MW |
| Plant Annual Gen: | 3106GWh[1] |
The Porce III Dam is an embankment dam on the Porce River northeast of Medellín in Antioquia Department, Colombia. The dam was constructed between 2004 and 2011 for the primary purpose of hydroelectric power generation.
Between 1974 and 1976, hydrological studies were carried out on the Porce River and between 1982 and 1983, studies regarding the river's hydroelectric development were completed. The study recommended the five projects, Porce I, Porce II, Porce III, Porce IV and Ermitaño. In December 1984, the feasibility report for Porce III was submitted and complementary studies were carried out between 1986 and 1996. In 2002, the design and consultancy contracts were awarded along with the environmental license issued.[2] In 2004, construction on the dam began and the river was diverted by 2007. By 2010, the dam began to impound the reservoir and was complete by 2010. Between 2011, all four generators were commissioned.[3]
The Porce III Dam is a tall and long concrete-face rock-fill type embankment dam. Its base width is about and it has a fill volume of . The dam's spillway is a chute-type and is located on its left side. It is controlled by four radial gates and has a maximum discharge of . The reservoir created by the dam has a 170000000m2 capacity of which 127000000m2 is active capacity. The reservoir has a surface area of . The catchment area for the dam and reservoir is . A submerged intake on the reservoir's left bank conducts water to the power station initially via a 12m (39feet) long and 10.2m (33.5feet) diameter upper headrace tunnel. At the terminus of this short tunnel, the water drops vertical shaft to the lower headrace tunnel which has the same diameter of the upper but is long. At the end of the lower headrace, it converts into four penstocks to supply each of the underground power house's 211MW Francis turbines with water. Once ejected from the power plant, it enters over of tailrace tunneling and is returned to the Porce River.[2]