Hydro-Meteorology and Water Budget of the Mara River Basin Under Land Use Change Scenarios

Abstract

Mara is a transboundary river located in Kenya and Tanzania and considered to be an important life line to the inhabitants of the Mara-Serengeti ecosystem. It is also a source of water for domestic water supply, irrigation, livestock and wildlife. The alarming increase of water demand as well as the decline in the river flow in recent years has been a major challenge for water resource managers and stakeholders. This has necessitated the knowledge of the available water resources in the basin at different times of the year. Historical rainfall, minimum and maximum stream flows were analyzed. Inter and intra-annual variability of trends in streamflow are discussed. Landsat imagery was utilized in order to analyze the land use land cover in the upper Mara River basin. The semi-distributed hydrological model, Soil and Water Assessment Tool (SWAT) was used to model the basin water balance and understand the hydrologic effect of the recent land use changes from forest-to-agriculture. The results of this study provided the potential hydrological impacts of three land use change scenarios in the upper Mara River basin. It also adds to the existing literature and knowledge base with a view of promoting better land use management practices in the basin

Modelling the rainfall–runoff process of the Mara River basin using the Soil and Water Assessment Tool

“…The one‐way forest–rangeland–agriculture conversion pattern of land use and the rainfall variability in amount and occurrence due to climate change were reported as the probable causes of extreme low flow and peak flows affecting the Mara ecosystem (Mati et al , ). Similarly, Mango et al (; ) looked at the effect of land use/cover and climate change on the discharge of the Amala and Nyangores Rivers and suggested that these changes may possibly affect the water flux in the upper Mara River. Available literature on hydrologic model applications in the MRB so far fall short of either the necessary detail (Mati et al , ) or spatial coverage (Mango et al , , b) to provide complete picture of rainfall–runoff process.…”

Water Demand and Allocation in the Mara River Basin, Kenya/Tanzania in the Face of Land Use Dynamics and Climate Variability

“…The model was calibrated over five years (1978 -1982) using observed discharge at Bomet, Mulot and Mara Mines stations ( Mango et al (2011a) for rain gage data (of negative NSE values for two years of calibration), the model performance was significantly improved in this study. The improvement could be attributed to the quality of input data such as rating curve used to estimate discharge data and longer period of simulation.…”

“…Recently, Mango et al (2011a;2011b) applied SWAT on the Nyangores and Amala tributaries of the upper Mara River to assess the impact of land use change using gage rainfall records and satellite rainfall estimates from 2002 to 2006. They reported that RFE performed better than gage rainfall records with NSE of (0.62, 0.39, Amala River) and (0.43, 0.23, Nyangores River) for the calibration and validation periods, respectively.…”

“…Available literature on hydrologic model applications in the MRB so far fall short of either the necessary detail or spatial coverage (Mango et al 2011a), (Mango et al 2011b) to provide complete picture of rainfall-runoff process. Understanding the interaction among the natural processes and human activities in the watershed may require a reliable and robust representation of relevant hydrologic processes.…”

“…Similarly, Mango et al (2011b;2011a) assessed the effect of land use/cover and climate change scenarios on the discharge of the Amala and Nyangores rivers (Figure 2.1), and concluded that these changes may result in 20 % -31 % increase in overland flow.…”