Aquifer Recharge Plant / SALT Architects

Architects: SALT Architects
Area: 15865 m²
Year: 2024
Photographs: Karl Rogers
Design Engineers: Water & Wastewater Engineering
Project Managers: JG Afrika
Structural Engineers: JG Afrika, WA Structural Design
Geotechnical Engineers: Peregrine Consultants
Contractors: Stefanutti Stocks
Fire Consultants: PMC Consultants
City: Cape Town
Country: South Africa

Aquifer Recharge Plant infrastructure project designed by SALT Architects in Cape Town offers a sustainable response to the city’s water crisis by purifying treated effluent and recharging the Cape Flats Aquifer, located in the False Bay Nature Reserve in Pelican Park. The design addresses the coastal site’s sandy terrain and harsh conditions with durable construction and a gravity-fed system of four linear filtration buildings featuring east-west facades with angled brick fins and narrow windows to filter light and prevent algae. The administrative building, positioned at the highest point, incorporates a brise soleil and glazed atrium, marking the facility’s entry and housing operational and administrative spaces designed for clarity and comfort. Sustainability strategies include thick concrete walls, face brick, passive thermal design, low-flow fixtures, and dune sand reuse. Though public access is restricted, the project elevates essential infrastructure into a civic setting that values its users, responds to its environment, and reflects the innovation required to meet contemporary challenges.

Aquifer recharge plant / salt architects

The Cape Flats Managed Aquifer Recharge (MAR) plant serves as a pioneering response to Cape Town’s ongoing water crisis, providing a sustainable strategy to secure the city’s future water supply. Located within the False Bay Nature Reserve in Pelican Park, the facility meets the need for long-term water management by treating effluent to potable standards and recharging the Cape Flats Aquifer. The site consists of a flat, sandy terrain bordered by dunes and is exposed to strong southeasterly winds and corrosive coastal conditions, all of which influenced the architectural and technical design approach.

At the core of the project is an innovative process developed by the civil engineers to recharge the Cape Flats Aquifer, a vital water resource for the region. Treated effluent is purified to potable standards and reinjected into the aquifer to sustain its levels. This system operates through a sequence of four linear filtration buildings, strategically positioned along an artificial slope to enable gravity-fed filtration. The process starts at the highest filtration building and progresses downward to the lowest, where the purified water is directed back into the aquifer. The long east-west facades of these buildings incorporate angled brick fins and narrow south-facing windows, producing a “gilled” appearance that filters light while inhibiting algae growth in the filtration system. These facades function as membranes, not for water but for sunlight, elevating the act of filtration into both a utilitarian and symbolic architectural gesture.

The administrative building, located at the highest point of the site, functions as the “head” of the facility, serving as a visible marker of human interaction and oversight within the industrial complex. Integrated into the first filtration building, it adopts the formal language of the gilled facades while introducing a subtle variation in rhythm. In this area, the fins open outward to form a loose brise soleil, creating a porous, screen-like layer that filters both light and the transition between interior and exterior. This architectural gesture emphasizes the administrative building’s role as a point of human interface, guiding visitors and marking entry. Behind the brise soleil, a double-volume glazed atrium offers a light-filled yet sheltered entrance space that welcomes users and guests.

Inside, the administrative block is arranged to prioritize both efficiency and comfort. The ground floor contains functional areas designated for plant operators, while the first floor includes offices, meeting rooms, and the plant’s control room. These spaces are intended to facilitate productivity and convey a sense of care and respect for the individuals working within the facility.

The project’s design recognizes the substantial embedded energy involved in the extensive concrete structures necessary for water retention, with walls and floors reaching up to 600 mm in thickness. As a result, sustainability was addressed through an emphasis on durability and long-term resource efficiency. Durable face brick was chosen for the facades, with its warm tones complementing the sandy surroundings while offering resistance to corrosion and requiring minimal maintenance. This focus on enduring construction not only extends the buildings’ lifespan but also supports their potential for future repurposing, reducing the likelihood of demolition at the end of their use.

Smaller, considered measures support this overall approach, including the reuse of dune sand from site excavations as backfill, the installation of low-flow sanitary fittings and waterless urinals, and the implementation of passive thermal strategies to reduce reliance on mechanical climate control. Though modest in scale, these interventions demonstrate a sustained commitment to efficiency and resourcefulness throughout the plant’s operational lifespan.

While the facility remains closed to the general public, its design moves beyond pure utility to affirm the dignity of infrastructure. By enhancing the experience of its operators and creating an environment marked by care and architectural intention, the project expresses respect and fosters a sense of pride. As a flagship initiative for the City of Cape Town, the MAR plant stands not only as a technical solution but also as a statement of the city’s commitment to sustainable and forward-thinking development. Its design accommodates educational visits, offering a physical demonstration of resilience in response to ongoing water scarcity.

The Cape Flats MAR plant exemplifies how architecture can elevate essential infrastructure into something more meaningful: a place that respects its users, engages thoughtfully with its environment, and embodies the innovation required to confront the urgent challenges of the present.