Climate Change, Water Resources and Food Security in the Lower Tana River basin, Kenya Charles Ndegwa, David Kuria, Fridah Kirimi, Felix Mutua*
ackground ana river basin sues  in the Tana basin roposed project approach roject stakeholders
The Tana River basin covers an area of 126,028 km². The upper basin comprises the slopes of the Aberdare and Mount Kenya mountain ranges. Rainfall amounts roughly correspond to the elevation. The highest rainfall (average of 1050 mm) is observed in the upper basin, while the lowest rainfall (average 500 mm) is  in the lower basin.
The upper Tana is characterized by rain-fed cash crop agriculture: tea, coffee, maize but also small tree stands. The middle and lower, drier, areas in the basin are mostly used as pastoralist grazing land, dry land farming and dry land forestry. A number of irrigation schemes are - both perennial irrigation and flood based systems along the main Tana River and some of the tributaries - are also found in this area. The coastal area of Tana Basin, including the islands of Lamu and others, differs from the rest of the lowlands – because of the humidity and also because of the intense development along the coast
Water in the Tana basin is used for electricity generation by five main hydropower stations in Tana  River – with two more being planned The stations are operated by KenGen  providing 40 to 64% of the national electricity demand. Nairobi obtains 70 to 80 % of its drinking water from Ndakaini reservoir The third large water use comprises medium-sized irrigation schemes, covering 68,700 hectares. In addition to these directly productive uses of water, sufficient base flow is also required in the delta area as low base-flows caused damage to the mangrove an reef systems near the Kiunga Marine National Reserve.
Tana Catchment Area also boasts of several protected and gazetted areas. This includes  four National Parks and eight Game Reserves, the major ones being the Aberdare Ranges, Mt. Kenya  Forest, Meru National Park Tsavo East National Park and the Tana River Primate Reserve. In these  natural landscapes ecosystem management is equally important.
Different challenges for upper middle and lower Tana te: National Water Master Plan 1992; Population census 1999
Over-abstraction locally: of surface water and, in some areas, groundwater Catchment degradation from land use changes that may affect recharge in this unit; risk of deterioration of water quality; A significant rate of urbanisation and related surface Agro-based factories which also contribute to water pollution; Encroachment of protected forests   and wetlands Encroachment, landslides, degradation and subsequent siltation and pollution of spring heads Localised heavy abstraction of surface water and groundwater for intensive commercial plantations (eucalyptus in particular); Water quality – fluoride and manganese levels are high in certain locations
Water scarcity – rainfall ranging between 400 m to 700 m; Unevenly distributed groundwater availability and seasonal variation of shallow groundwater levels Salinity of groundwater in several areas; Uncontrolled sand mining Sedimentation in reservoirs; No protection of natural trees stands – leading to removal of trees and no regeneration; No management of grazing areas (with a few exceptions) – as a result most palatable grasses are overgrazed and woody species take the upper hand Invasion of alien species – in particular prosopis juliflora.
ictuation of water levels in the main rivers ater scarcity during the dry season; et season mage due to peak rainfall events croachment of land by invasive species inity of groundwater – with salinity increasing with stance from dry river streams (lagh nited groundwater storage; coastal areas) deterioration of water quality as a result intrusion of saline water.
 n the coastal islands) groundwater pollution from werage er use of the southern wells of the Lamu aquifer bstantial competition for land and water in the Tana lta Droughts and floods  -  perfect catalysts for pastoral conflicts
Investigating and developing all opportunities for the use of local aquifers for artificial recharge, storage, recovery of storm-runoff and any excess riverflows. Dune infiltration in the coastal areas – from several sources – so as to safeguard the curr and future supply for urban and tourist settlements along the coast.  . Developing opportunities for small-scale surface water storage in the arid landscape, Making best use of the flood based farming Develop a coherent participatory plan for the Tana Delta – where there are various high value landscape functions competing related to biodiversity, rangeland, and commercial agriculture. Developing appropriate mechanisms to control the timing and quantity of artificial flood releases from the newly planned reservoirs Planting trees and seeding grass to serve as ecosystem stabilizers.
Basin is poorly observed The best temporal resolution is daily More than 50% of reporting stations  do not have data No  existing   early   warning   system   for
floods and drought Satellite  estimates  of  precipitation compares poorly with the few obs stations It is not clear how climate change will impact this basin More floods? More drought?
egional climate projected to hange tremendously Mean and extreme rainfall likely to increase Temperature likely to increase hat about the East African climate ange paradox?  “ observed drying d higher frequency of droughts in e last 3 decades versus the pjected wetter region by GCMs ? “
o address  some of these issues, we need to: emonstrate quantitative and qualitative improvement of water cycle observations emonstrate flood and drought early warning capability ssess climate change impacts on floods, droughts and crop production rototype data and information integration and sharing systems nprove observational, modeling and application capacity
Demonstrate quantitative and qualitative improvement of water cycle observation Prototype near-real time rainfall observation and data dissemination systems by coupling satellite and in-situ measurements which are used as inputs into flood prediction. Develop comprehensive in-situ and satellite observation data archive for improvin monitoring capability of water cycle and developing hydrological models to be use for early warning. Develop long-term and comprehensive climate observation data archives which an used for climate change analysis climate projection model bias correction. Demonstrate early warning capability of water and food security
Develop coupled hydrological – crop models for converting climatological and meteorological data and information to usable  information of water resources an food management Prototype real-time data management, modeling and information dissemination systems. Evaluate climate change impacts on floods, droughts and food production Select GCMs which can express the regional climate properly. Implement bias correction and downscaling (statistical- and dynamic-) of the selected GCMs.
Develop a socio-economic data archive Compare changes of frequency and intensity of flood, drought and food production. Develop an integrated water portal for improving data accessibility and data sharing. Improve observational, modeling and application capacity Develop training modules of satellite remote sensing, modeling, bias correction an downscaling, make design of training courses on integrated observations, early warning and climate change assessment, and offer the courses. Promote secondary educational programs in collaboration with universities
Water Resource management authority (WRMA) Meteorological Services Department ormerly KML water and Sewerage Companies – Murang’s Nyeri Water and S hyatta University of Agriculture and (JKUAT),The University of Tokyo, Power Generating companies – KenGen, Geothermal Development Company (GDC) Tana Water Services Board, Tana Athi River Development Authority (TÁRDA) Kenya Agricultural Research Institute (KARI) Kenya Red Cross (KRC)
NACOSTI
Ministry of Environment and Mine Resources ,Kenya National Bureau Statistics (KNBS) Regional Center for Mapping of Resources for Development (RCMR ● Department of Resource Surveys a Remote Sensing (DRSRS) Inds. nank you