Project Spotlight: Costa Rica's Paacume water mega-project

A significant percentage of the economic activity of Costa Rica's Chorotega region, located in the northern province of Guanacaste, is agriculture-based or dependent on hydroelectric power generation. The Arenal Tempisque irrigation district (DDRAT), which serves the area by drawing water from the Tempisque river, helps the country obtain between US$150-200mn a year thanks to its agricultural production.

However, the region's location in the so-called Central American dry corridor, makes it extremely vulnerable to droughts (most of the area sees no rainfall during five months of the year). This, in turn, creates major negative social and economic impacts for population.

Without the irrigation district, the area located in the left margins of the Tempisco river -which includes the subdivisions of Carrillo, Santa Cruz, and Nicoya - would have low agricultural productivity. Ironically, however, said area is the one with more possibilities to adapt to climate change effects, according to authorities. The aforementioned subdivisions include some 40,000ha of land that is suitable for agricultural production. 

As a consequence of this, the government has recognized the importance of launching a comprehensive project that can help ensure water in the area for irrigation purposes, but also for water consumption, sustainable tourism and power generation.

Project details

The administration of President Luis Guillermo Solís is moving forward on a comprehensive US$500mn water supply project for human consumption and irrigation, also known as the water supply system for the mid-river basin of the Tempisque river and coastal communities (PAACUME).

The initiative is being managed by national groundwater, irrigation and drainage service Senara, and involves building the following infrastructure:

• A dam on the Piedras river with a 485m-long, 29.5m-high wall, which is expected to cover an area of 850ha;

• Widening 20km of the second section of the western canal of the Arenal Tempisque irrigation district, as well as building a new 35km stretch - the canal's third - from the Cabuyo river to the village of Palmira;

• Construction of a 300km distribution network to supply water to 1,000 farmers in the localities of Carrillo, Santa Cruz and Nicoya;

• The relevant infrastructure for the dam to produce between 36-44GWh of hydro power to meet the demand of 14,500 homes.

Once complete, the new infrastructure will supply water for different uses: 16.5m3/s will be used to irrigate 18,800ha of agricultural land, 2m3/s will go to human consumption and 1.5m3/s to supply tourist areas. Some 36GW of power will also be produced each year.

The water that will be used for human consumption will be managed by national water utility AyA, which will be tasked with treating the water and distributing it to local residents.

More specifically, the water will be delivered to AyA at the towns of Sardinal, Filadelfia, Santa Cruz and Nicoya. The amount of water to be distributed will serve to supply 500,000 people for the next 50 years.

The project will directly benefit the town of Bagaces (with the construction of the dam), and the subdivisions of Santa Cruz, Carrillo, and Nicoya (through the irrigation component of the initiative).

Project progress

The preliminary studies and the environmental impact assessment for the initiative have already been completed. 

The studies were carried out with a US$175,000 technical cooperation grant from the Central American Bank for Economic Integration (Cabei).

As for the investment, Cabei is expected to provide US$425mn in financing to complete the works, while the Costa Rican government will provide the remaining US$75mn.

The government has already presented a bill to advance the project. The bill calls for establishing new limits for the Lomas de Barbudal biological reserve, part of the Tempisque conservation area, located near the proposed site.

If approved, the proposal would entail changing the area's land-use designation and authorizing the national system of conservation areas (Sinac) to use the wood resulting from the logging of trees that will take place during the construction works.

The construction works for the aforementioned infrastructure will lead to the flooding of some 113ha of the reserve. For that reason, authorities will purchase a total of 531ha of land neighboring the protected area as compensation.

The legislature is now set to review the bill and vote on its approval. If the bill is passed according to schedule, the contracting process for the works is expected to begin next year, allowing construction to begin by 2019.

The deadline to conclude the works has been set for 2022.

PICTURED: Map showing the location where the project's dam (the initiative's first component) will be built. CREDIT: Senara.