Three partner countries in East Africa are involved at this stage of the project, with groundwater observatories established in coastal sites in Comoros, Kenya and Tanzania. The coastal zones in each country provide a diversity of geological, environmental and social typologies to study.
Grande Comore (Ngazidja) island in the Comoros Archipelago
Grande Comore is the largest and most westerly island in the Comoros Archipelago. A volcanic island, its topography is dominated by high peaks rising to 2360m above sea level. The population (~320000) is largely situated around the coastal fringe of the island with most in the island’s capital Moroni in the west. Water infrastructure on the island is poor. Many rely on rainwater harvesting in low capacity and often contaminated tanks. There are issues with saline intrusion in many existing wells and the water table is deep and difficult to access.
Oichili well, Grande Comore, drilled in a recent lava flow in one of the driest area of the island
Situated to the north of Mombasa city on the Kenyan coast, Kilifi is a coastal town lying either side of a creek, estuary of the Goshi river. Geologically the area is underlain by Holocene alluvial sediments at the coast, progressing through Quaternary aeolian and superficial sands, lagoonal sands, coral and coral breccias towards Pliocene Sandstones and Jurassic Shales in the raised, terraced interior. Fishing and tourism are major industries in the area. Upmarket beach resorts and residences contrast with the poverty of the urban area. Issues with water availability and quality are widespread. Though surface water is piped to the area from Taita Taveta to the northwest, most of the population rely on borehole supplies. Our initial surveys reveal many boreholes abandoned due to poor construction, collapse and high salinities and poor source protection resulting in contamination.
The coast at Kilifi, KE.
Kilwa district lies in Lindi province in SE Tanzania, encompassing a peninsula bounded on the west by the Mavudyi, Kikwaju, Msekera and Nahimba river estuaries and a number of populated islands including Kisiwani and Songo Mnara. The peninsula and islands are largely underlain by Miocene clays and mudstones and coral limestone.
Issues with water availability affect both urban and rural populations. The main urban areas are Kilwa Kivinge to the north of the peninsula and Kilwa Masoko at the south. The urban population is growing rapidly and current water needs are inadequate with currently only 50% of needs met in Kilwa Masoko using a combination of wells and piped water from springs in Mpara in the north. The existing infrastructure is aged and there are frequent issues with damaged pumps due to surges in electrical supply to the area. The islands (Kisiwani and Songo Mnara) are of tremendous archaeological importance as a former port city on the Swahili coast and are classified as a UNESCO World Heritage Site. The completion of restoration and conservation works together with a new road south from Dar es Salaam will mean that tourism is a growth area in this region.
View North from Kilwa Kisiwani (island) to Kilwa Masoko