Assessing the Hydrological Conditions of the Usangu Wetlands in Tanzania

Shadrack Mwakalila

doi:10.4236/jwarp.2011.312097

Abstract

Although wetlands make up less than 10% of Tanzania, their “critical, life support, ecosystem services” sustain over 95% of lives, of wildlife and of livestock. They provide security as sources of food, water, energy, economy and livelihoods, therefore, the aim of this paper is to address the current hydrologic conditions of Usangu wetlands. Several approaches were used in the collection of data for analysis. Both primary and sec- ondary data was collected and analysed. The key finding shows that, the overall area of the Usangu Wetlands is divided into two main portions, the Eastern Wetland and the Western Wetland, the core wetland, the Ihefu Swamp varies between 30 and 65 km2, whereas the seasonally wetted areas varies between 260 and 1800 km2. Major perennial rivers which feed the Ihefu swamp in Usangu wetlands include Kimani, Mbalali, Ndembera and the Great Ruaha River. The contribution from Mbalali River ranges between 69.17% and 47.78%; from Ndembera River ranges between 25% and 13.83%; from Kimani River ranges between 25% and 8.33% and from Great Ruaha River contribution ranges 24.0% and 2.96%. The irrigated agriculture is most important as a user of water and impacts most heavily on wetlands. Abstraction of water for agriculture is leading to dried up rivers, falling ground water tables, salinated soil and polluted waterways.

Highlights

As natural ecosystems, wetlands are an essential part of the ecology and like any other resources they provide social and economic benefits to human life, whether directly or indirectly
The irrigated agriculture is most important as a user of water and impacts most heavily on wetlands
Abstraction of water for agriculture is leading to dried up rivers, falling ground water tables, salinated soil and polluted waterways

Summary

Introduction

Wetlands are an essential part of the ecology and like any other resources they provide social and economic benefits to human life, whether directly or indirectly These benefits include among others irrigation agriculture, fishing, water supply, timber production, transport, recreation, tourism, papyrus, sediment/ toxicant retention, flood control, groundwater recharge and discharge [1,2,3]. We realize that wetlands make up less than 10% of Tanzania, their “critical, life support services” sustain over 95% of our lives, our crops, our wildlife and our livestock They provide security to 80% of society, the rural poor, as sources of food, water, economy and livelihoods.

Water Inflow to Ihefu Swamp and Vulnerability

Great Ruaha River and the Upper Catchments of the River

Findings

Conclusions