Los viajes del agua (III)

- Recreational infrastructure for rainwater collection, treatment and visibility -

The Añorga quarry in San Sebastian is located within a territory where water and hydraulic infrastructures have played a determining role in the definition of the site.
However, these architectures are often invisible and remain alien to the pulse of people and the physical context. Valuing as an opportunity the high rainfall in the quarry as well as its topographical condition - a large impermeable surface where the water flows -, a large recreational infrastructure is proposed.

It collects, treats and uses this rainwater understanding the potential that the infrastructures and the water itself have as the germ of programmes and spaces.
The intervention reactivates the quarry with water as the protagonists, where with its different qualities, qualities and speeds, it runs through permeable and hydrophilic architectures that make it visible together with its processes.

4. The pools

Rainwater, once in continuous movement, after being treated is now treated in a series of pools.
The stereotomic architecture that forms the base is composed of a system of concrete vessels for the formation of the pools. The space is crowned by barrel vaults, which create a space in semi-darkness only interrupted by the introduction of patios and skylights.

Floor plan

Vault and pool details

5. The natural pools

Vault - pool formation

Vaults - patios intersection

Vaults geometries

Axonometric view

The natural swimming pools are arranged in pairs, the smaller of which contains the gravel and purifying plants necessary for the natural renewal of the water.
The organic matter suspended in the water generates NH3 ammonia. Ammonia is a nutrient for algae but not for higher plants, and is also toxic to fish and people. A biological filter transforms NH3 ammonia into NO3 nitrate by providing oxygen.
The nitrate is perfectly assimilable by the plants that absorb it and remove it from the system so that it is not available for algae. This process of ammonia oxidation is carried out by a series of beneficial bacteria that live in the biological filter, the nitrosomes.

Light introduction

The concrete vaulted architecture creates a space in penumbra, which is punctually interrupted with the introduction of skylights and cylindrical shaped courtyards at the ends of the space.