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Rapid Ecological Assessment

Upper Macal River, Cayo District, Belize

Fieldwork as part of an EIA for the controversial Chalillo hydro project was carried out by Martin Meadows and Jan Meerman from 6-12 April 1999. The resulting EIA report has been widely disputed.

Construction of the facility has meanwhile completed. The picture below shows the situation on August 10, 2004. On the picture, the Macal River comes in from right-hand side and flows out towards the bottom. The finished part of the dam is visible on the northern shore (in the right half of the picture.

The picture below shows the situation on March 20, 2005. The dam covers the entire width of the gorge and is nearly up to its intended height. In the background the smoldering ashes of the forest behind the dam is visible. This forest needed to be removed prior to the filling of the hydro-lake in order to prevent massive quantities of decaying organic matter in the lake. These fires are large enough to be picked up by satellite.

Chalillo Dam in Macal River Belize nearing completion

The dam was completed in September 2005 and commissioned on November 15, 2005 (on the same day BEL announced an electricity rate hike). The picture below shows the situation at April 4, 2006, with the hydro lake still filling up slowly. In spite of above average rainfall figures following the closure of the dam, the lake level rose antagonizingly slow and the lake did not start overflowing until July 12, 2006. The slow rise of the lake has not been explained but could have been caused by karstic nature of the southern edge of the basin, which can be expected to "leak"

Upper Macal Area in Belize

At its highest point the hydro dam is 150 feet tall and its span is 420 feet. It took 200,000 cubic yards of concrete and holds 120 million cubic meters of water. Two turbine motors have a capacity of creating 8.3 megawatts of power. The water is then sent down river about 12 miles to the Mollejon Plant, lower in the same Macal River, where the volume from Chalillo is supposed to increase that plant's output from 80 gigawatts hours to 160 gigawatts hours.

The Chalillo facility was allegedly constructed at a cost of over US$100 million. The dam is owned by BECOL which, like BEL, is owned by Fortis.

During April of 1999, Both Martin Meadows and Jan Meerman collected ecological data along the upper Macal river in the areas designated for inundation. A total of 4 vegetation transects (click to see the transects) were established along which structure and composition of the flora was established. This was the first effort of this nature to be carried out in this area. The map below indicates in red the transects established.

Location of vegetation transects allong the Macal River
Upper Macal Ecosystems. Click for larger image

The Upper Macal/Raspaculo area encompasses 4 major ecosystems (click the map for a larger image):

Tropical evergreen seasonal broadleaf hill forest over calcareous soils.

Tropical evergreen seasonal broadleaf hill forest on acidic soils.

Tropical evergreen seasonal needle-leaf hill forest.

Deciduous broadleaf lowland riparian shrubland in hills.

The latter is the most interesting ecosystem. The total area of “Deciduous broadleaf riparian shrubland in hills” along the Macal + Raspaculo = 4079 acres or 1651 hectares. The total nation wide coverage of this ecosystem is only 6947 acres or 2811 hectares. The proposed hydro lake will flood 1459 acres or 590 ha of this habitat. The area of “Deciduous broadleaf riparian shrubland in hills” along the Macal + Raspaculo that will disappear in the hydro lake is 34% of the Macal habitat surface or 21% of the national surface.

For more information on the ecosystems see the Belize Ecosystems Map.

The (false color) satellite image to the right shows the actual extend of the Chalillo lake on March 21, 2006. The Macal River and thus the proposed hydro lake follows the fault between the sandstones of the Mountain Pine Ridge Massif in the North and the Karst Limestone formations to the south. The difference of the geologic formations and their associated vegetation cover can clearly be seen. Satellite Image of Upper Macal River region. Click for larger image

See results of the 1999 Ecological Assessment of the Upper Macal River

 

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Last modified: April 6, 2007