Day 1: The System is Launched
The project begins with the deployment of 0.5 square kilometers of mycelium-based reflective panels in the shallow, nitrate-rich inflow areas of Theewaterskloof Dam. These panels are produced locally, using mycelium spores combined with wood waste from nearby construction projects. Cape Town’s climate allows the panels to be grown on-site, making production sustainable and efficient.
Once installed, the panels begin to reduce evaporation by 6 liters per square meter per day and serve as the foundation for an aquaponic system that absorbs nitrates from the incoming water. From the very start, the system reduces water loss and begins addressing nutrient pollution.
Month 1: First Harvests and Initial Water Savings
The amount of water saved by covering 1% of the dam roughly equates to a reduction of about 1% in Cape Town’s overall water usage. 4.5 million liters of water are saved daily.
By the end of the first month, the system produces around 34,000 kilograms of salad daily. The food production effectively removes 90 kg of nitrates from the dam daily, helping to maintain a balanced aquatic ecosystem.
The aquaponic system is highly efficient, saving around 13 liters of water per head of salad produced compared to conventional methods.
This results in a total water savings of approximately 442,211 liters daily, bringing the overall daily water saving up to about 4.9 million liters.
Month 1: First Harvests and Initial
Water Savings
One year into the project, the system continues producing 34,247 kilograms of salat daily, more than enough to meet local demand. Additionally, 1.1 million kg of Nitrates have been removed over the year,
reducing nitrate concentrations and preventing ecosystem imbalances.
The system’s efficiency in removing nitrates has lowered nutrient levels, but the project must ensure nitrate levels don’t drop too low for a healthy ecosystem. To address this, the system maintains a steady balance by controlling water flow and nutrient absorption. Water savings continue, saving 1.6 billion liters from evaporation over the past year.
Year 2: Introducing Fish to Balance Nitrogen Levels
In the second year, fish like tilapia are introduced into the inflow zones to prevent nitrogen levels from dropping too low. Without the fish, the system would risk becoming too efficient at removing nitrates, which could lead to nutrient levels falling below what's needed for a healthy aquatic ecosystem.
The fish naturally produce nitrogen through their waste, which cycles through the aquaponic system and provides nutrients for plant growth. This maintains a balanced nitrogen level, ensuring the system doesn’t over-purify the water while continuing to remove excess nitrates. The fish also provide an additional food source, making the system more diverse and resilient
Year 3:
Balanced Water Quality and Food Production
The introduction of fish has stabilized nitrogen levels, allowing the aquaponic system to continue thriving without depleting essential nutrients. With the balanced nutrient cycle, the system continues to produce both salad and fish, contributing to food security and maintaining a healthy water environment.
Farmers involved in this project benefit financially by selling their crops while also receiving compensation for water saved from evaporation. This approach means that farmers do not incur charges for water usage from the dam; instead, they are rewarded for conserving water. Additionally, they enjoy free housing spaces,
promoting a sustainable lifestyle.
This system enables water conservation, provides affordable local food production, and offers free living spaces while improving nitrogen levels and the overall ecosystem health. It strengthens the social fabric of the community by ensuring food security and environmental sustainability.
WATER FARMING
Cape Town is experiencing significant water shortages, worsened by fertilizer and nitrogen runoff into water bodies from agricultural practices. This project at Theewaterskloof Dam aims to tackle these issues by using mycelium-based reflective panels, which function as the aquaponic system. These panels significantly reduce evaporation while food production helps clean the water by absorbing nitrates in the shallow areas, where the runoff enters the lake (red).
Additionally, the panels can be used to construct local buildings that provide good insulation against heat and can float, offering new living opportunities for farmers. The city establishes and provides these new free living spaces for local farmers while also supplying them with free water for the aquaponic system.
Farmers could be further subsidized for the amount of water saved from evaporation, creating an additional income stream alongside sales from freshly produced crops. This approach not only supports water conservation and nitrate removal but also enhances community resilience by enabling locals to provide affordable food while improving water quality and ecosystem health.