An e-publication by the World Agroforestry Centre
RESEARCH ABSTRACTS AND KEY POLICY
QUESTIONS
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An e-publication by the World Agroforestry Centre |
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RESEARCH ABSTRACTS AND KEY POLICY
QUESTIONS |
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THEME 3. LOSS OF WATERSHED FUNCTIONS Posters on Watershed Functions Reflections on the Upper Ewaso Ng'iro River Basin Studies in Kenya by David N Mungai1, B Kiteme2 and Chin K Ong3 Introduction Mt. Kenya and associated mountain ranges are important in many ways to the welfare of millions people living in the vicinity of the mountains but also to the Kenyan economy in general. The mountains provide water for Kenya's major rivers and their tributaries upon which agriculture, tourism and power generation depend. The rivers also constitute an important source of domestic water supply. The mountain and the associated highlands are endowed with fertile soils and their slopes covered with forests and other vegetation forms which provide timber, fuelwood and a rich biodiversity including rare species and medicinal plants. Mt. Kenya is also one of the international benchmark sites for the study of mountain ecosystems. The importance for research of the Mt. Kenya area was recognized in the mid 1970s by scientists at the Universities of Berne, Switzerland and Nairobi, Kenya. This paper describes the ecological, demographic, planning and policy formulation and implementation studies which have been carried out in the Mt. Kenya and Upper Ewaso Ng'iro region of Kenya at various spatial scales.
An extensive measurement network was established to monitor the climate, water, soil, and vegetation resources as well as landuse and cover. The major aims of this monitoring system are to (1) collect baseline data for climate, water, soils, vegetation and landuse in the catchment, (2) collect long-term data for the assessment of variability or trends of the monitored parameters and their impact on resource availability, productivity and degradation, (3) provide data for detailed analysis of specific processes or of different management strategies and (4) provide data for model adaptation or development for tactical and strategic advisories to all stakeholders including researchers.
The distribution of 100 climatological stations varies from 920 m at the catchment outlet to 4,500 m at the peak of Mt. Kenya. The soils of the Upper Ewaso Ng'iro catchment have been mapped and characterized at various scales. There are numerous other soil studies at farm or settlement level. In addition, runoff, soil loss and soil moisture data have been collected at 20 representative sites for ten different landuse types. In the run off plots, soil cover has been monitored. River discharge measurements have been made since 1960 through a hydrological network initiated and maintained by the Water Department. Sediment discharge has also been monitored for some of the rivers for specific studies where assessment of catchment soil loss was necessary. As at 1997, there were 32 river gauging stations in the Upper Ewaso Ng'iro catchment, all manned by the LRP staff. To assess river water abstraction in the major rivers, 8 river abstraction furrows each fitted with a flume were constructed at various times between 1991 and 1995.Landuse and cover are periodically assessed using remote sensing data. These are complemented by observations of ground cover condition at 5 small catchments.
The growth of the population and the demographic characteristics since pre-colonial times have been documented. The demographic studies show a population growth rate of up to 8% per annum. The indications from these studies is that the population in the Upper Ewaso Ng'iro catchment will continue to grow given particularly the high rates of immigration with consequences on the natural resources of water, vegetation and soil. The translation of research findings into recommendations and the transfer of these to the planning and development agencies in the region have been important activities for the LRP. To address as fully as possible the constraints to sustainable resource use and development, interdisciplinary research and transfer methods of the findings have been given high priority. Self-help groups are common in the area and they act as important vehicles for rural development. A study was carried out between 1986 and 1989 to find out to what extent the self-help groups could function as entry points in the transfer of research findings and development activities. The study was regional in character covering an area of some 10,000 km2 and 354 peasant self-help groups and a time frame of twenty years (1970-1990).
Land use changes and water conflict The drammatic land use changes and intensification of farming activities, due to population increase and the subsequent rise in demand for irrigation water have led to serious degradation of land and water resources. Today, there is less water reaching the lower parts of the basin than thirty years ago due to increased number of abstractions most of which are illegal. The occassional drying up of the Ewaso Ng'iro river and some of its tributaries leading to movements by the pastoral communities and wildlife into the upper reaches of the catchment in search of water and pasture attests to this. This situation has served to increase and complicate conflicts over water resources between farmers in the upper reaches of the basin and other interested groups in the lower areas of the catchment.
Following land use and ownership dynamics in the district, (through subdivision of large scale farms into small-scale holdings) new farming systems have been subsequently introduced. These changes have taken place without adequate information to the new settlers on how to adjust and adapt to the new agroclimatic conditions. This resulted to the development of farming systems that put pressure on the scarce natural resources especially water.
Development efforts and specific intervention policies for water resource use have often proved inadequate to respond effectively to the needs and conflicts arising from competition for water whose causes and effects assume a regional dimension. Moreover, catchment protection has been hindered by a lack of a comprehensive environmental protection policy.
The minimum data set may be defined as the lowest amount of data which can provide an accurate assessment of the baseline biophysical and socioeconomic conditions including the rates at which changes in the state variables are occurring. In defining such a minimum data set, a number of boundary conditions need to be defined. The characterization of a study catchment in terms of the control variables of the various hydrological processes is necessary in determining the sampling intensity. The control variables which should be used include altitude and land use/land cover. A knowledge of the differentiation of areas with different rainfall and storm generating mechanisms would also be very important. Where spatially and temporally representative hydroclimatological data are available, an attempt should be made to regionalize and the use the derived regions to set up a monitoring system. The available long term data should also be used to determine the efficiency in parameter estimation using data of various lengths. The studies in the upper Ewaso Ngiro were lucky in that a fairly representative network existed before the project. The network belonged either to the Government or to private land owners and it monitored only a few parameters.
Interdisciplinary team The combination of research for basic solutions on the one hand and area specific and problem-orientated research on the other, is difficult and is a growing problem. It requires a professionally and highly qualified interdisciplinary team (from both socio-economic and natural sciences) that is necessary for the formulation and implementation of specific research activities.
The building up of an integrated database on ecological processes and socio-economic dynamics is a time -consuming, professionally/scientifically complex and financially demanding process. The most challenging task is to maintain the database updated, consistent, extensive and easily accessible to those who want to use it. Furthermore, it was necessary to integrate information from two scientific disciplines, natural and socio-economic sciences. As the institution expands its activities with more stakeholders and geographical coverage, it became more difficult to integrate individual research projects and accommodate various scientific interests.
The process of database development through research is not complete if it is not linked to development process through extension and transfer activities. The main constraint in accomplishing this task lies in the capacity and ability of the institution and its collaborating partners to maintain a sustained transfer activity to ensure continuous information dissemination to relevant users at all levels of development process throughout the period There is a general lack of technical and financial/logistical capacity among the key collaborating institutions, especially government sector departments, who are expected to take the findings to the beneficiaries.
As the institution establishes itself to a level of sub-national and national scientific recognition, more institution seek for formal association and affiliation. This creates enormous demand on the parts of the research institution in respect of professional, technical, and logistical and financial supports. Consequently, a number of requests could not be granted.
Since every institution is established and operated in accordance with set goals and objectives, it becomes practically difficult to tackle new and emerging environmental issues as well as continue with long term monitoring.
Footnote_______________ 1 University of Nairobi 2 Laikipia Research Programme 3 ICRAF Nairobi, Kenya |