Rand Water Zanzibar – Gelsenwasser, OOWV

The project participants

  • International partner
  • German partners

Rand Water Zanzibar

Rand Water Zanzibar is a semi-autonomous water supply utility responsible for the overall management of water supply in Zanzibar, including the main islands of Unguja and Pemba. The main task of Rand Water Zanzibar is to invest in, operate, and maintain the water supply and wastewater infrastructure, and to ensure a clean and safe water supply in accordance with legal regulations. With 308 boreholes on Unguja and Pemba, groundwater is the most important water source for Rand Water Zanzibar. A continuing challenge is the approximately 22,000 unregulated private boreholes. Zanzibar faces significant challenges in water supply, as Rand Water Zanzibar is able to cover only about 60% of the total demand across all sectors.

Die GELSENWASSER AG

GELSENWASSER AG (Gelsenkirchen, Germany) is a diverse infrastructure company for water supply, wastewater management, electricity and gas supplies and off-grid power generation. The public listed company with over 5,500 employees in the group is one of Germany’s largest water utilities. The water works in Haltern is one of the largest in Europe.

Oldenburgisch-Ostfriesische Wasserverband (OOWV)

Oldenburgisch-Ostfriesischer Wasserverband (Oldenburg, Germany) supplies water to more than one million people in north-western Germany. With 46 sewage treatment plants, the water association is also responsible for controlled wastewater management in 38 municipalities and for one wastewater services association. OOWV has around 850 staff members. As a corporation under public law, it operates on a non-profit basis and re-invests all surpluses.

The project

The project covers practical technical aspects (with a focus on groundwater management, optimisation of pumping operations, operation of transmission and distribution networks, and reduction of water losses), as well as capacity building made accessible through partnerships with German water supply companies.

The cornerstone of the partnership is the peer-to-peer exchange between the utilities. This forms the basis for the bilateral exchange with Rand Water Zanzibar. The aim is to improve and expand the knowledge and skills of the staff. A work plan specifically tailored to the partnership is intended to support capacity building within the collaboration.

Work Packages of the Partnership

To ensure a comprehensive approach that meets the needs of the partnership, two working groups will be established: water supply and well construction.

Water distribution (GW)

Gelsenwasser will be engaged in the area of drinking water distribution. In particular, given the number of leakages and the need for their prompt detection and repair, a revision of processes is required.

Initially, a District Metered Area (DMA) will be established. Using ultrasonic measurements, insights into the condition and characteristics of the supply network will be obtained. From this, measures can be derived to achieve optimisation. It will also be necessary to assess the extent to which leak locations can be identified using simple electroacoustic methods.

Personnel training is also of considerable importance. Regular training sessions for Zanzibari colleagues, both on site and in Germany, are intended to lead to a more routine handling of tasks. This will be complemented by the development of guidance materials and tools, such as a pipe damage report. These will subsequently enable the structured management of construction sites and the identification of defective sections of the pipeline network. These will subsequently enable the structured management of construction sites and the identification of defective sections of pipeline.

Inventory management is also to be optimised so that repair materials are readily available in sufficient quantities and in a hygienically safe condition, ensuring that work can be carried out promptly.

Well construction and rehabilitation (OOWV)

The well construction working group has two focal points: quantity / abstraction and quality. With regard to the focus on quantity and abstraction, the “flow rate vs. total volume” concept will be pursued. In the first step, findings from exploratory surveys as well as suitable geological profiles will be discussed. This serves to gain familiarity with and understanding of the overburden, as well as to determine the maximum hydrologically effective distance from the coastal strip. In the second step, groundwater monitoring points will be discussed and optimised where possible. Thirdly, the design of well intakes and their advantages is to be considered.

The quality focus is addressed through visual inspections, hygiene and structural measures, as well as cleaning and rehabilitation. This includes consideration of the need for visual inspections, the construction of protective casings or wellheads, possible subsequent annular space sealing, as well as various methods of effective mechanical well cleaning.

As of: April 2026

Factsheets

Knowledge transfer and cooperation between Ukraine and Germany

Fact sheet about the cooperation between Kyivvodokanal and HAMBURG WASSER in the frame of a solidarity partnership and for the future of the City of Kyiv and the Free and Hanseatic City …

Project profile

Duration

September 2025 – April 2027

Focal topics

  • Water distribution
  • Well construction and rehabilitation