Browsing by Author "Kilungu, Halima"

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    Assessment of water requirements to sustain ecological functions
    (University of Dar es Salaam, 2008) Kilungu, Halima
    The study employing the habitat simulation method to assess water requirement for sustaining aquatic ecological functions. It was conducted at three representative river reaches namely Amala River near Kapimolwa bridge-BBM1, mid Mara-BBM2 and lower Mara near Kenya Tanzania border-BBM3 in the Mara River. Hydraulic parameters such as water discharge, velocity, and depth as well as ecological parameters (e.g. channel index and fish) collected at the three sites in March 2007 (corresponding to low flow conditions) were used in physical habitat simulation model-PHABSIM to simulate changes in river physical microhabitats and weighted usable area (WUA) for key river biota due to change in river flow. The customized database for most flow sensitive fish species found in Mara River, Labeo victorianus, was used as an indicator of suitable flows to maintain ecosystem heath. Based on simulated flows at different life stages of this species, the ecosystem, as a whole, will function well at a discharge range of 1-11 m3/s. At the existing river management regime such discharges can be achieved at Q50 and Q85. Recommended river management options for maintenance of reasonable flow are discharges of 1.24-4 m3/s for BBM1, 2.5-11 m3/s for BBM2, and 3.2-9.4m3is for BBM3. These flows have to be maintained to mimic the natural river flow regime.