Water dynamics in the Umba river sub-catchment of Tanzania: water resource allocation for livelihoods

Abstract

This study seeks to answer the question: how do changes in biophysical environment and social dynamics that include institutions affects water resource availability and allocation for livelihoods in the Umba River sub-catchment? I combined qualitative and quantitative methods within a single investigation whereby: quantitative methods traced and assessed land use and cover changes from 1975-2015 as well as tracing rainfall trends and extremes events since the 1960s across the study villages to understand how these changes affect water resource availability and livelihoods. Qualitative methods were used to gather information on livelihood capital, histories and how policies have been changing, especially the villagisation programme, as well as communities’ perceptions on water scarcity and how they react and adjust to those changes. I argue that mixed methods increase opportunities for data triangulation and corroboration of results to understand contemporary water related challenges in the global south.

The conceptual framework combined the concepts of resilience, hydrosocial territories and waterscapes to demonstrate how human-environmental interactions and related changes that include power relations are linked to water access and allocation challenges and how these shape livelihood pathways in the Umba area. This approach revealed how changes in both biophysical environment (including land use and climate) and social dynamics that include institutions together have affected water resources availability, access and allocation and that in turn have affected water dependent livelihoods and related trajectories in the Umba area. Hydrosocial and waterscapes lenses revealed that available legal institutions have challenges and are influenced by politics and interference from government officers with interest in water and that the situation has caused some water infrastructures and water access to be allocated for some groups and places while denying other groups within the same sub-catchment. This has led to contestations and conflicts among water users themselves and institutions. I argue that the availability of water resources for livelihoods is complex and uncertain due to changes in biophysical environment, social dimensions, institutions and power relations which are interlinked and cannot be understood using a single based discipline and approach.

Results demonstrate that the study area has experienced significant changes in land use and climate over the last 40 years. Settlement and scattered cultivation have increased by 1761% and 395% respectively. Linked to that, natural forests have decreased by 48%, bushland decreased by 28% and grassland by 55%. Trends in annual mean rainfall appear to be declining but the Mann-Kendall test did not detect any statistically significant trend (P > 0.05). However, extreme events assessed using the SPI for 55 and 33 years at two weather station locations indicated that the Umba area is experiencing increasing droughts events compared to wet events and the trend test has proved to be statistically significant (P < 0.05). Also, the seasonal analysis indicates interannual and interseasonal rainfall variabilities in terms of amount, onset, cessation and length of the season.

Water access for livelihood is shaped by how it is allocated. Due to skewed power relationships within formal institutions, water is allocated in such a way that some groups within the catchment have water access while others not. Also, in the sub-catchment some locations such as midstream and downstream have water infrastructures while those in off-stream and upstream areas have limited infrastructure rights. This has led to contestation and conflicts. In the Umba area, there are six types of water related conflicts which include; farmers versus pastoralists; farmers versus formal institutions; community versus conservationists; upstream versus downstream; irrigators versus other water users; and farmer (s) versus farmers. Therefore, rather than simply being the effect of changes in land use and climate, changes in water availability in the sub-catchment are due to a combination of variations in rainfall, changes in land use and land cover, and the politics and practice of allocation of water via complex hydrosocial waterscapes. Over time, this combination of forces has affected availability and access to water leading to struggle, contestations and conflicts between people living in different locations along the river, and within each area.