The shallow Sabaki estuary experiences greater rates of water and sediment exchange as compared to the relatively deeper Tana estuary. However, the cohesive clay sediments are trapped within the estuaries in mangrove forest wetlands and in sheltered intertidal areas that are now occupied by mudflats. This has resulted in net export of sediments out of the two estuaries. The tidal asymmetry in the two estuaries is characterized by ebb tidal flow dominance due to presence of mangrove forests, wide intertidal areas and freshwater input. This has led to deepening of the estuary channels with the result that tidal wave penetrates much deeper into the estuary and seawater intrudes up to 10 km inside the estuary. On the other hand, there has been a substantial reduction in both freshwater input and sediment supply into the Tana Delta. The shallow nature of the Sabaki estuary ensures reduced penetration of the semi-diurnal tidal wave into the estuary and seawater intrusion is restricted to 2.5 km of the estuary.

In the much smaller Sabaki estuary, there has been a reduction in freshwater input and an increase in sediment supply leading to heavy accretion. The study shows that the hydrologic dynamics controlling water circulation including the trapping and exchange of terrigenous sediments in the two estuaries is a function of the river discharge and tidal forcing. The two estuaries are important for biodiversity conservation, sustainability of socio-economic livelihoods and provision of global environmental benefits. The horizontal and vertical distributions of tidal current velocities, salinity and total suspended sediment concentrations (TSSC) within the estuaries enabled determination of the degree of stratification and the extent to which mixing of seawater and freshwater leads to the formation of the maximum turbidity zone (TMZ) in the two estuaries.

The study involved the determination of river freshwater and sediment fluxes, as well as water exchange and sediment fluxes at the mouths of the two estuaries. ‘‘I would call upon the locals not to provoke the animals by stoning them and destroying their habitats, as this would only escalate the conflicts,’’ he said.This study is focused on the determination of the extent to which changes in river freshwater and sediment input affects the sustainability of the Tana Delta and Sabaki estuaries in Kenya. He also said they have begun constructing a watchtower on his one-acre plot of land near the river to guard the animals and warn people of their presence.Īdriano Graldello, an honorary KWS warden, promised to support the trust to conserve the estuary and protect the animals. ‘‘We are working together with stakeholders including KWS and locals, to guard the animals,” he said. Kene called on the government to gazette the Sabaki estuary as an important bird area as it was home to unique bird species.įurther, he called on the Kenya Wildlife Service to establish a camp in the area to help prevent human-wildlife conflicts. They said the rogue hippos have also destroyed acres of farm produce in the area leaving residents to suffer. Locals said the hippos normally attack at night and a dusk to dawn curfew in areas adjacent to the river was in place. Kene who took journalists on a tour of the estuary on Saturday said a donor had already been identified and was willing to construct the wall or set up a solar-powered electric fence.

‘‘There are more than 50 hippopotamuses at the Sabaki estuary, they should be confined so that residents can live in peace and stop attacking them,’’ he said. Kene said that due to the constant attacks residents were threatening to kill the hippos in self-defence. Trust founder Dominic Kene said the hippos were terrorising residents because their grazing areas have been turned into farmlands and residential areas. The hippos have killed over four people and injured four others in the last one year, leading to an outcry by residents of the area that action be taken to avert more. The Hippo Campus Sabaki Conservancy Trust wants the hippos to be confined to the river and its riparian area to prevent the frequent attacks by the wildlife. A Malindi conservationist has urged authorities to build a wall on the River Sabaki estuary to protect more than 50 hippos and avert human-wildlife conflicts.