Saving Poechos

The efforts to avoid the major artificial mirror of water in Peru gives up to the sedimentation.

 

 

By Nelson Peñaherrera Castillo

 

 

    LANCONES, Peru – What lacks in Piura Region is water. It’s nhot a new story, it’s lifetime’s rather. RThat is why the long agricultural tradition was looked for keeping on, what received more pushing in the last 100 years. The first irrigation projects for Middle Chira and Middle Piura Valleys are older than 19^th-century ending.

 

 

Engineers had considered to transfer Quiroz River, Chira Basin, for providing water to a barren sector between Las Lomas and Tambogrande Districts. The project was ignited until 20^th-century midwhen San Lorenzo Irrigation started the slow transformation of a desert into an exuberant valley.

 

 

However, San Lorenzo’s wáter flow –projected to supply the whole Piura Valley—was not enough, so more sources were needed to assure the most coverage as possible. In 1969, Piura-native Juan Velasco alvarado’s military government approved an irrigation project that, taking Chira River’s water, the hugest in the region, could enlarge the agricultural frontier of that valley but also supplying Middle and Lower Piura ones.

 

 

Three years later, Poechos Reservoir was started to build, the largest artificial mirror of water in Peru that could become to hold until 1 billion cubic meters, so the needs of farmers around the cities of Sullana and Piura should be satisfied.

 

 

The work finished and opened in 1976… with 885 million cubic meters of water accumulated in the reservoir, but its first fireproof came in 1983 – El Niño had brought heavy rains sslamming the zone during the first half of that year, the strongest in almost half a century. Poechos did not suffered from considerable damages and the enough water amount could be controlled to avoid more floods than the already caused by the rainy episode.

 

 

The story repeated in 1998. Although less intense, a 4-month rainy period caused by El Niño tested the structure again, and at least externally, there were no considerable damages. But the problem was not in the dry infrastructure but in the bottom of the water – the rainy periods had carried alluvial matter that was accumulating on the reservoir’s floor, beginning a slow sedimentation process.

 

 

    The veredict of the sediment

The Piura City-based Chira-Piura Special Project (PECHP as its acronyme in Spanish), that manages the Poechos facilities  and the whole irrigation estimates 70 million cubic meters of sediment accumulated in 1983, and 80 million in 1998. The forecasted was 6 million cubic meters per year, according to its own comments.

 

 

“The sedimentation is fundamentally caused by the soil erosion that is produced at highlansdue to those areas are unprotected by the deforestation in the zone ,” PECHP explained on a report made by its Surveys & Environment Office. According to it, until 2004the amount of sediment in Poechos was 397 .3 million cubic meters, reducing its capacity to 44.9%.

 

 

The regarding concern is general. The late Antonio Brack, a recognized Peruvian ecologist, and Cecilia Mendiola belief that, at that rhythm, the reservoir is about 35 years lasting, after what would turn a swamp, a low storage capability. Add to this the hydric stress periods and the existence of rice croplands, that require more water flow.

 

 

Vilcazán Project was approved in May 2016, that consists in building a little dam on the course of Quiroz River, a Chira River’s tributary, between the districts of Ayabaca and Pacaipampa, but its water would not be diverted to Poechos but San Lorenzo.

 

 

14 years before, then Sullana City-based agrinomical engineer Jorge Córdova opined that the choices to save the water mirror were: rising the reservoir level, digging the bottom, or dynamiting the water floor. The most expensive would be digging it. Mr Córdova estimated the useful life of the reservoir in a decade counted up since 2002.

 

 

    Satellite reservoirs

Working to assure the water flow, the farmers themselves projected their own solutions. The Miguel Checa Irrigators Committee belief that one alternative to Poechos’ sedimentation was building two smallest reservoirs supplied by the big reservoir’s water but guaranteeing the liquid stock.

 

 

The first mirror would be built in Santa Victoria Zone, next to Poechos, for storing 150,000 cubic meters of water. The second one would be projected 9 miles to the southwest, in Casuras, that would store until 180,000 cubic meters of water. Both reservoirs would be connected by a simple canal, while Santa Victoria’s could get the water from Poechos by an abductor canal. The idea is both reservoirs store liquid during the overflow times.

 

 

The proposal was introduced on September 9^th, 2005, during a meeting organized by PECHP for explaining the advances of its enhancing of Poechos’ Development Project, developed in coordination with the Regional Government of Piura. Joaquín Balarezo, then PECHP’s chairman, commented to include the proposal into the profile. The project was signed up on the National System of Public Investment.

 

 

    And the inspiration made a model

The farmers were not alone advocating to introduce the alternative reservoirs project. In fact, they inspired a bunch of high-school students.

 

 

Since July 2005, the Sullana City-based Miguel Cortés’ 1^st Grade High-School students began to research on that idea by checking out on media reports and talking to the own farmers. “The point is having awareness, that the people learn the water is life,” their tutor and advisor teacher Cecilia González Cobeña opined.

 

 

The students who joined the work team were: Josselin Adrianzén Parra, Guillermo Gómez Ramírez, Miluska Guerra Guerra, Rodrigo Herrera Godos, Luis Muñoz Sánchez, and Lucyana Rivera Condori.  

 

 

They visited santa Victoria, Lancones District, and Casuras, Querecotillo District, to check out that most farmers supported the initiative. “The communities have no water, they consume polluted waterfrom the creeks,” the students commented. “The people mostly harvest rice and fruits, but lands have no production because of water lack.” The most impacting them was many locals got it from wells.

 

 

As a result of their research, they performed about 1351 square miles on a scale model that shows clearly the assessment and the quantity of granted people, 7000 families in a first phase, at the Middle and Upper Chira Valleys, although the benefit is for the whole valley. The effort deserved them the second place at the 11^th School Festival of Science & Technology, organized in 2005 by the Education authorities in Sullana.

 

 

A frustrated presentation in a fórum about the wáter, organized by another school in that city, updated the need to build the reservoirs. The students ignored how much the project costedand how long it was going to build, but they had gifted its model to Irrigators Committee for having a visual that eases to explain it.

 

 

With reports by Bilma Castro and El Regional de Piura in Sullana, El Tiempo and Cipca in Piura, and CEPES and Perú ecológico in Lima.

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