Greening the Islands Foundation

Chumbe Island in Zanzibar: 25 years a Pioneer of Zero-impact Eco-architecture and Operations

Chumbe Island Coral Park (CHICOP) in Zanzibar, Tanzania, is a not-for-profit conservation business that has created from 1992, the first privately managed marine protected area in the world, hosting a fully protected coral reef sanctuary and forest reserve. Park management and comprehensive conservation education programs for local schools and communities are fully funded by a small ecolodge on the island.


Opening for tourists in 1998, CHICOP has from its outset been committed to ecologically sustainable architecture and operations that have close to zero impact on the sensitive terrestrial and marine ecology of Chumbe Island.

Conditions were challenging. Chumbe Island is a pristine fossil coral island that has no fresh water supply other than seasonal rains. In addition, the sensitive coral communities in the fringing Reef Sanctuary had to be protected from any sewerage runoff and pollution. These are the most common problems associated with coastal development that pollute beaches and kill coral reefs.

Therefore, for developing the Visitors’ Centre and the Ecolodge, CHICOP commissioned the best available expertise for Eco-architecture, such as Prof. Per Krusche, the Director of the Institut fuer Entwicklungsplanung und Siedlungswesen of the Technical University of Braunschweig (Germany), and his colleagues.

They created a uniquely innovative design, where each building functions as a self-sufficient unit that generates its own water and energy, with rainwater catchment and filtration, solar water heating and photovoltaic electricity, while sewage is avoided. In detail, outstanding features of the Eco-Architecture and Eco-Technology on the island are:

  • Local building technologies and materials. All buildings on Chumbe Island reflect local architectural low-energy and low-input traditions, cultures and technologies. Constructed from locally available natural renewable building materials and technologies, this also created a thriving market for local producers, particularly also for small farmers who found a market for products from the coconut tree, a crop that had been long neglected.

  • Natural ventilation. The spatial orientation and design of all buildings makes maximum use of the prevailing direction of the annual Indian Ocean trade winds. Guests can regulate the flow of the sea breeze through the bungalow with hand-woven mat panels. Thus no energy-demanding air-conditioning is required.

  • Rainwater catchment. All buildings have been designed to make maximum use of rainwater that is collected by the palm-thatched roofs and filtered through combined gravel and sand filters, to be stored in large cisterns under the floor of each building. To our knowledge, Chumbe Island is the only project harvesting rainwater from palm-thatched roofs worldwide! This could be a model for low-cost water harvesting in rural communities where palm-thatched roofs also predominate.

  • Composting toilets. The eco-bungalows have composting toilets that recycle human and organic waste without using any flush water. They reduce organic waste to one sixth of its original volume and produce compost and fertilizer. Organic kitchen waste is recycled in the compost beds that provide for the compost toilets. Any other waste is removed from the island.

  • Vegetative greywater filtration. To avoid introducing unwanted nutrients, waste water (greywater) from the shower, washbasin and kitchen pass through a filter before entering a plant bed that has been sealed from its surroundings. Plants that absorb large amounts of phosphates and nitrates are used here to remove these nutrients before the water enters the eco-system. All laundry is washed off the island.

  • Solar power for light, communication and water heating. Photovoltaic panels provide for lights and other electricity needs. Batteries for PCs, cameras and mobile phones can be charged from solar batteries at the Education Centre. In all bungalows, shower water is heated by solar water heating panels.

  • Avoiding light pollution at night. To protect nocturnal wildlife from light pollution, the walkways, nature trails and beach areas are not artificially illuminated. Guests are given solar powered torches for walking along the pathways between the eco-bungalows and the Restaurant at night. This protects feeding and breeding patters of nocturnal animals, and also helps preserve and view one of the most stunning attractions of Chumbe Island: the rare giant Coconut Crabs (Birgus latro), red-listed by IUCN. This largest land crab on Earth has now found refuge on Chumbe Island and produced the probably greatest known population concentration worldwide.

  • Cooking energy. Against a backdrop of the rapid deforestation in the country, the search for an appropriate clean and renewable cooking energy was a challenge to the project. To be manageable, a restaurant has to offer a variety of dishes that are prepared and served hot according to a strict time schedule for breakfast, lunch and dinner times, irrespective of the number of guests and of weather patterns and peak sunshine hours. For cooking energy, we have experimented with a wide range of cookers: two models of solar cookers, the so-called solar boxes and a parabolic solar-cooker, a low-pressure gas cooker, kerosene cookers and traditional charcoal stoves. Of the several options examined, gas stoves were the most appropriate and cost-effective option.

  • Zero single-use plastics policy in operations. Rather than importing industrially processed and typically plastic packaged produce as is often done in the hospitality industry, our policy is based on “farm to fork” supply chains, where our restaurant serves the delicious Zanzibari cuisine based on healthy seasonally available fresh foodstuff. These are supplied daily from local farmers’ market and transported in large baskets avoiding any single-use plastics packaging materials. Drinking water is supplied in recycled and refillable glass bottles, while organic waste is composted for re-use in composting toilets, while all inorganic waste is taken off the island.

Article written by: Sibylle Riedmiller, Director, Chumbe Island Coral Park (CHICOP) Ltd.

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