Integrated Flow Assessment

Tanzania's National Water Policy provides that water for maintenance of the environment will be accorded second priority in allocation, after water for basic human needs. Also, the Environmental Management Act requires Basin Water Boards to reserve water for ecosystems. But how do we know how much water the environment needs? Pioneered by Australia, South Africa and other countries struggling with allocating limited water resources, Integrated Flow Assessment (EIFA) methodologies have become accepted internationally as an appropriate tool for determining the water requirements of the environment.

Tanzania has little experience and capacity in conducting such flow assessments to support the provisions of its national water policy. The International Union for Conservation of Nature (IUCN), through its Water & Nature Initiative, the European Commission through a grant from EU-ACP Water Facility, and the Global Environment Facility (GEF) through the UNDP, supported an integrated flow assessment in Pangani River Basin as a part of the Pangani River Basin Management Project.

The IFA developed an understanding of the hydrology of the river basin, the flow related nature and functioning of the river ecosystem and the links between the ecosystem and the social and economic values of t he river’s resources. The information generated from the flow assessment was used to organise ecological, social and economic knowledge of the basin to aid future planning and management of its water resources. A scenario based approach was used so that many possible pathways into the future – the scenarios – could be explored.

Objectives
• To generate baseline data on the condition of rivers, wet lands and the estuary against which the impact of water-related decision-making can be monitored in future
• To enhance the understanding among PBWB and Ministry of Water and Irrigation staff of the relationship between flow, river health and the people who use the river;
• To create an awareness of the trade-offs to be made between water development and natural-resource protection;
• To develop simple tools to help guide water-resource management and water allocations in the Pangani River Basin;
• To build capacity that will enable Pangani Basin Water Board (PBWB) to act as a nucleus of expertise for flow assessment related work in other areas;
• To support the National Water Policy (NAWAPO 2002) and the National Environmental Management Act (2004).

Action Plan
South African (from Southern Waters, Anchor Environmental and Emzantsi Systems) and Tanzanian specialists consulted for more than a year to design a custom flow assessment program for Pangani River Basin to both provide necessary technical information to support decision making about water resources and build capacity within Tanzania for conducting flow assessments.
The flow assessment produced a number of outputs (containing valuable information for the Pangani Basin Water Board (PBWB) to use in decision making) such as:
• a hydrology model for the basin;
• delineat ion of the study areas to select representative sampling areas;
• a health assessment of the rivers and estuary report ;
• a baseline socio-economic assessment report – describing people’s relationship to water and river resources;
• state of the basin report – a synthesis of the understanding of the river systems and its economies;
• specialist studies reports - hydraulics, hydropower operations, riparian vegetation, fisheries and invertebrates, macroeconomic and climate change;
• a flow assessment scenario evaluation Decision Support System (DSS) tool
• future of the basin report - outlines the approach used to develop scenarios and describes five scenarios in detail along with how climate change will impacts the future flow regime in the basin

Coupled with these outputs was capacity building and training on environmental flow concept s, how to enter information into the DSS, and how to interpret output s from the scenarios developed and evaluated through the DSS. There was also awareness raising to the general public on the importance of allocating water to the environment as well as other sectors.

Flows for the Future
The PBWB inserted different kinds of management options into the basin hydrology model. Some scenarios added flow back into the river to investigate how river health and fisheries could be improved, and how this would affect food product ion and hydropower generation. Others looked at how climate change might affect the basin’s water resources. Fifteen scenarios were created in total. All assumed more efficient use of water. The hydrology model showed that each of them would result in a different flow regime.

For more information read – Future of the Basin report [insert link]
Integrated Flow Assessment briefing note [insert link]

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Our Contacts

Pangani River Basin Management Project
P. O Box 7617 - Moshi, Tanzania.

Tel.: +255 (0)27 275 2780
Fax: +255 (027) 2753097
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