Influence of Water Resource Use Patterns on the Lorian Swamp Ecosystem

Abstract

River ecosystems are under intense pressure from water user‟s resultant from human or economic activities. Population pressure are over-stretching most of Kenya‟s water towers including the Ewaso Nyiro water catchment areas which was the study area. Developing countries including Kenya have identified water as a vital ingredient in meeting the socio-economic developments as envisioned in Vision 2030. Among the proposed projects was the construction of Isiolo mega dam to support the development of Resort City against the backdrop of depleted water resources in the Ewaso Nyiro River due to water abstractions, large scale irrigation farms and used ranches in the upstream. The study investigated the influence of water resource use patterns on the Lorian swamp ecosystem, which narrowed down on the trend of water levels and pasture in time and space and the overall effects of the proposed Isiolo dam on the ecosystem services namely water and pasture. The data was collected from four sub-location namely, Merti, Mulandanur, Matarba and Saleti in Isiolo County. The respondents were randomly selected using a sampling formula from the targeted sub locations. 100 respondents were administered with questionnaires to obtain the data needed. Additionally, focus group discussion was conducted to gather in-depth information as a triangulation measure. Observations added valuable information to the overall data collection. The field data was uploaded on statistical package for social sciences (SPSS) and the data was analyzed using descriptive statistics. River flow data from CETRAD were calculated and tabulated to triangulate primary data for comparison and validation. The results were presented in bar charts, percentages and mean. The data analysis indicated significant water reduction in Ewaso Nyiro over the years affecting the Lorian Swamp ecosystem. The research finding indicates that from 1960-1969, the cummulative water discharge was 964 million cubic meters and from 2001-2010 it was 572 million cubic meters showing a major decline in water discharge with a difference of 392 million cubic meters translating to 40% reduction over four decades. Further analysis showed that pasture and water are currently adequate but under threat due to loss of traditional governance system, invasive species (Prosopis Juliflora), climate change, water abstraction upstream for farming and other uses, deforestation, encroachment of the catchment arears and ever-increasing population. It was therefore concluded that the further development of proposed dam will have serious effects on water discharge of the Ewaso Nyiro River. The Dam will be anticipated to take 214millions cubic meter against the backdrop of the available annual average water of 583 million cubic meters translating to annual reduction of water in the river by 37%. The future impacts will shrink the Lorian swamp ecosystem from the current 2918-kilometer square to 1809-kilometer square affecting forage production, water reduction including the underground water, Loss of indigenous trees and increased conflict over limited resources. The research further concluded that to balance human developments and sustainability of the Lorian swamp ecosystem the water uptake in the dam be spread over three years at a rate of 71.4 million cubic meter, about 12.3% of annual water discharge. It means that the dam will be filled in three years. The research study further recommends that the National government should explore sustainable timeline to fill the dam in meeting the water demand without compromising the critical Lorian Swamp Ecosystem. Additionally, the County government should constitute an Independent Institution to conduct potential Environmental and Social Impact for the proposed dam. Also, the traditional governance system of the resource management should be formalized and strengthened so as to manage the Lorian Swamp Ecosystem. Finally, the need to curb the serious threat from the invasive species (Prosopis Juliflora) and the concerned Authority should consider innovative ways of taming it.