Praia do Lago by PROAP – Estudos e Projectos de Arquitectura Paisagista Lda

Built in 2024 / 2025 Built Landscapes / 2025 Entries / 2025 Infrastructure Projects / Portugal /
proap.pt

Alqueva dams the Guadiana river and two of its aflluents; it was designed to alleviate the water shortage problem in the Alentejo region and in this way revitalise agricultural activity in the region. Although it also contributes to energy production, it constitutes the main point of a vast water distribution system, both for public supply and irrigation of agricultural fields; it has a surface area (at maximum altitude) of 250 km² serving 120.000m2 of irrigated land, making it the largest artificial lake in Europe. Given its surroundings and the quality of its water, tourism and recreational aspects also play an important economic role.

The Praia do Lago project arose from the need to utilise an irrigation and hydropower infrastructure for the creation of a recreational facility in an area subject to high temperatures, where the use of water can be of extreme importance to the population. The creation of a river beach was proposed in the vicinity of the nautical post and caravan parking area.

Since it is a rainwater retention basin, fluctuations in water level (due not only to rainfall but also to water use for irrigation) and evapotranspiration dynamics – especially in summer –affect the surrounding landscape by revealing or flooding portions of land, leaving debris, mud and dust, offering ever-changing scenarios depending on the weather and the seasons. The access and use of the river beach areas are variable, as are the conditions of usability (due to the presence of mud, dust, algae, etc.), and the project has to deal with the variability of these parameters: it is a pulsating project, working from the observation of dynamics that prefigure different conditions of accessibility and usability depending on the water level in the basin.

In drafting the project, we worked considering a water level elevation range of 8 metres, trying to give shape to a changeable and comfortable space, capable of responding to the needs of use at different times and circumstances of use, while maintaining a coherent and quality image.

In addition to the creation of the leisure and bathing space, which provides an important shelter from the summer heat over a large period of time, the intelligence of the project also lies in the exploitation of the main purpose of the infrastructure (irrigation) as a tool for both the redevelopment of the water and the creation of green sectors in the areas that are being uncovered as the water level drops.

By means of a circular pumping system powered by photovoltaic panels (thus a system with no energy consumption and neutral in terms of carbon), water is pumped from the dam and subsequently decanted, purified and recirculated: in this way, the very operation of the system ensures that the water quality of the beach is increased and upgraded.

A second subterranean irrigation system makes it possible to irrigate the areas that can be used as beaches: as these are uncovered following the reduction of the dam’s storage quota sector by sector, a simple seeded area creates comfortable and mud- and dust-free resting spaces (a green beach), also guaranteeing evapotranspiration that helps reduce temperatures and increase comfort.