SANTA CRUZ DE TENERIFE, March 2. (EUROPE PRESS) –
The Cabildo de Tenerife has awarded the re-waterproofing of the Barranco de Benijos raft, in the municipality of La Orotava, for 1,076,693 euros. The works will begin in April and will have an execution period of eleven months, a period in which an alternative reservoir will be installed to guarantee the supply of water to the 560 farmers in the area.
The island councilor for Agriculture, Javier Parrilla, and the mayor of La Orotava, Francisco Linares, have visited the facilities together with the manager of the public company Balsas de Tenerife (Balten), Ana Sánchez. During the meeting, the councilor thanked “the involvement of the mayor and the rest of the Municipal Corporation in this important project for the entire Orotava Valley” and recalled that this initiative “is part of the Re-waterproofing Plan started in 2019”.
Currently more than 560 subscribers depend on the water from this pond. “For this reason, a 760-cubic-meter tank will be installed, which will allow farmers in the area to have the peace of mind of being able to irrigate their crops while the cleaning and re-waterproofing work is carried out,” said the councilor.
Francisco Linares valued the Cabildo’s commitment to the primary sector, meeting the demands raised by the City Council to help farmers and ranchers in the area. “Now an important investment is being made with this much-needed project to promote better water quality and use for all irrigators, and from which more than half a thousand farmers will benefit,” he remarked. In the same way, he valued the installation of an auxiliary tank to guarantee the supply during the works.
In 2017, after carrying out several monitoring tests, it was detected that the geomembrane showed wear greater than 59.13 percent in certain areas. “Hence the need to proceed with its re-waterproofing, which will be carried out through a novel containment and slope stabilization system,” said Parrilla.
The works will also focus on water inlets; in the crest of the pond, slopes, bottom and anchoring elements; the installation of a floating water intake; in the demolition of infrastructures that today are useless and in the modernization of the control equipment of the galleries.
The Benijos pond was the fifth of the ten built within the framework of the Island Corporation’s Plan for Ponds in the North of Tenerife. Its construction was carried out between 1985 and 1986, when José Segura Clavell was president, with the aim of serving as a regulating pond for the midlands of the municipality of Realejo and La Orotava.
It is prepared to receive water from the Salto Manuel, Las Palomeras and Caramujo galleries, as well as from the San Jerónimo well, which allows it to maintain the highest quality water from underground sources that Balten manages.
Since 1990, the Benijos raft has undergone several small repairs, however, its first and only waterproofing took place in 1986, with a guarantee period of 10 years, the councilor recalled.
The height it reaches at its crown is 549.20 meters above sea level and it has a storage capacity of 206,373 cubic meters. In addition, it has a pond bottom surface of 6,469.97 square meters (m2), a free surface at the maximum level of the reservoir of 21,018.92m2, a crest surface of 22,082.76m2, and a lateral slope surface to be waterproofed of 17,296.20m2, which allows the pond to have a supply capacity of 19 cubic meters per second of agricultural water.
SLOPES, BOTTOM AND ANCHORAGE ELEMENTS.
Among other tasks, the sludge accumulated during more than 33 years of service will be extracted, as well as all the material from the runoff of 2009. Subsequently, a cleaning will be carried out, “avoiding the removal of the existing geomembrane”, and all the bags of gravel found at the top of the various levels of the pool will be removed.
Javier Parrilla explained that in the partial repair of the slopes damaged in 2009, manual means were used to compact the area, not mechanical means, “which has caused pinching in the current geomembrane.” This problem will be solved by placing a cementitious geocomposite, “an element of first level technological innovation that will avoid problems in the following years”.
On the other hand, a floating intake system will be installed. In this regard, the counselor assures that Balten’s experience in similar ponds has shown that the use of these intakes means that better quality water is distributed, “since it avoids supplying water that contains suspended sludge or that is in the process of eutrophication , which are waters with a high level of organic load”.
Likewise, the existing valves of the water intakes and bottom drainage will be replaced, with an investment of around 3,700 euros, and all the areas of the pond will be waterproofed, starting with the crown anchors in the 539 meters of perimeter. Subsequently, the geotextile will be installed and the waterproofing geomembrane on it.
