| dc.description.abstract | Historically, water has been managed from a supply perspective with an emphasis on
short-term economic growth from the use of the water. In this respect many
municipalities, water service boards and other local authorities strive to supply water in
abundance to their community. This has led to unprecedented environmental
degradation.
This has been witnessed in the over-consumption of Upper Athi River and Upper Tana
River for supply to the City of Nairobi. There is a danger of similar situation recurring
on the Kibos River for abstraction to the City of Kisumu. The water-resources planners
such as water supply, hydropower, and irrigation engineers, need to give due
emphasis to understanding of the need for environmental flows required to maintain
the health of the ecosystem of these rivers.
Most of the ~ethods developed so far are project specific or basin specific and cannot
be readily applied in Kenya as hydrological and physical characteristics of the
rivers/basins for which the methods are developed, are different from that of Kenyan
rivers/basins. There is therefore a need to select standard methods and software/s
which can be used at national level irrespective of the type and scale of project under
consideration. his research has used HEC- Ecological Functioning Model (EFM) an
open source software in water resources planning (in the Kenyan context) through
modeling of Kisumu Water Supply and Sanitation Long Term Action Plan, using Kibos
River as source of water.
The three environmental indicators employed for the research are fish (Labeo, Clarias
and Barbus), micro-invertebrates in general and Nyamasaria swamp as wetland.
The methods applied for assessment of risk level are modified method derived from
Davies and Humphries (1996) for Risk Levels Assessment based on Modified Key
Ecological Variables and the method developed by Tannent in 1976 for identified critical
minimum flows required for Fish, Wildlife and Recreation in streams. .
The research has revealed that there will be environmental change on Kibos River due
to the proposed intake/diversion weir on Kibos River. It is expected that there will be
significant migration of fishes from the affected reach of the river to the reach upstream
of the diversion weir and to the river reach downstream of Awach and Kibos
confluence. This can only happen if the run-of-river. scheme treatment plant is operated
at 48,000 m3/day throughout the year.
July 2013 Page xii of xii
If the city is supplied at 36,000 m3/day as run-of-river scheme and if necessary
mitigation measures are taken the water supply project can be compatibly integrated in
the ecosystem. | en |
