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PANGANI RIVER SYSTEM

Future of the Basin Report - 2011 Tanzania

Project Partners

The Pangani River Basin Management Project is generating technical information and developing participatory forums to strengthen Integrated Water Resources Management in the Pangani Basin, including mainstreaming climate change, to support the equitable provision and wise governance of freshwater for livelihoods and environment for current and future generations.

The Pangani Basin Water Board is implementing the project with technical assistance from the World Conservation Union (IUCN), the Netherlands Development Organization (SNV) and the local NGO PAMOJA. �� !��"��European Commission through a grant from the EU-ACP Water Facility, and the Global Environment Facility through UNDP.

Contents

Future of the Basin Report .................................................................................................................1

Team ...................................................................................................................................................2

Foreword ............................................................................................................................................5

Overview of the Basin.........................................................................................................................6

Hydrology of the Basin .......................................................................................................................8

Summary of present condition ..........................................................................................................10

Site summary of river condition ........................................................................................................ 11

Integrated Water Resource Management ........................................................................................12

Environmental Flows ........................................................................................................................14

The Pangani Integrated Flow Assessment approach .......................................................................16

The Pangani water development scenarios ....................................................................................17

How the scenarios were interpreted and evaluated .........................................................................18

Our starting point for the Pangani scenarios: the present day .........................................................20

Summary of the development scenarios ..........................................................................................32

Effects of Climate Change ................................................................................................................34

��!�� #�$� ......................................................36

Conclusion ........................................................................................................................................37

Way forward .....................................................................................................................................38

Further reading .................................................................................................................................39

Published by: Pangani Basin Water Board IUCN - Eastern and Southern Africa Regional Programme

Copyright: © 2011 Pangani Basin Water Board and International Union for Conservation of Nature and Natural Resources

Reproduction of this publication for education or other non-commercial purposes is authorized without prior written permission from the copyright holder, provided the source is fully acknowledged. Reproduction of this publication for resale or other commercial purpose is prohibited without prior written permission of the copyright holder.

Citation: PBWB/IUCN (2011). Pangani River System - Future of the Basin Report. Moshi, Tanzania: PBWB and Nairobi, Kenya: IUCN Eastern and Southern Africa Regional Programme. 39pp.

ISBN: 978-2-8317-1250-5

Designed by: Gordon Arara, ESARO Publications Unit

Printed by: Kulgraphics Ltd

Photos: Photos were contributed by the Environmental Flow Assessment team members, IUCN staff, Job de Graaf and Taco Anema.

This publication is based on the South African River Health Programme Reports.

Available from:Pangani Basin Water BoardBox 7617 Moshi [email protected]

�� Box 68200 Nairobi 00200 [email protected]

��$ ��%�� #�� !��!��"��IUCN. The designation of geographical entities in this book and the presentation of the material do not imply the expression of any opinion whatsoever on the part of the Government of Tanzania or IUCN concerning the legal status of any country, territory or area or of its authorities or concerning the delimitation of its frontiers or boundaries.

Credits

Future of the Basin Report

In 2002, a detailed situation analysis of water and environmental issues was done for the Pangani Basin. Following that, a series of pilot projects funded by the Water and Nature Initiative (WANI) of IUCN and by DFID led to the development of a Pangani River Basin Management Project (PRBMP) that continued until 2011. The project consists of an Integrated Flows Assessment, strengthening water governance and community participation, assessing vulnerability to climate change and promoting appropriate adaptations, and supporting integrated water management planning for the basin.

�� &''*��&''+�� !��"�� $��;�� <�� <��!� ��=��<��>��?� ��Q�� !�#�$� �� physical, chemical and biological nature of the river ecosystem, and the importance of the river in peoples’ lives. From this work, the Project Partners published a State of the Basin Report in 2007. This summarised present understanding of the nature and health of the river ecosystem, and of how people use it.

Seven groups of Tanzanian specialists then reviewed key topics on which information was sparse: climate ��<�X�� X�� !�� X�� X��$��X�� !��lakes and swamps; and the riverine vegetation.

Following this, the Team completed the next phase of the project. Working with the Pangani Basin Water Z!��=��<��?��[*�� !��$�� !�� ranging from rehabilitation and high-level protection of the river to maximum exploitation of its water for hydropower or irrigated crops. The 15 scenarios were analysed, using all the understanding gained to date, to predict how each of them could change the river from the headwaters to the estuary, and also how these changes in the river system could affect the people who use it. The team recorded this work in a Scenario Report.

�� <��$� � �� <�� !��Q�� \��\�� !� ��change were used to re-run three of the scenarios with climate change added. By comparing the three scenarios with and without climate change, the additional changes that could occur simply because of climate became apparent.

�� ]��!��?� ��>�� < Q�� !��!��!��^��!� ��?� ��>��%�� !� ��=��<��?� ��Z!��?��provides some information on the hydrology of the basin. It then outlines the approach used to develop �� !��_��!!��!�� <��change. This will help the government and other stakeholders to understand what the future could be like, and to discuss and negotiate on the future that they wish for.

��>�� $�� $��!��$��Q

1THE FUTURE OF THE BASIN REPORT

Name Organization Title

Project Design and Implementation

`�Q�{��"��^��;�� =��<��?� ��?�� ?� ��Z!��

`�Q�|�� ^��}�� =��<��?� ��?�� ?� ��Z!��

Mr. Sylvand Kamugisha IUCN/PRBMP Project Co-ordinator

Mr. William Luanda IUCN/PRBMP Administration

Dr Kelly West** IUCN Regional Programme Co-ordinator

Ms. Katharine Cross IUCN Regional Co-ordinator (Acting) � � ��

`�Q�|��Z$�� =��<��Z!��

Dr Emmanuel Mwendera* * * IUCN Regional Co-ordinator Water and Wetlands Programme

International Environmental Flow Assessment MentorsDr Jackie King Southern Waters/ University of Cape Town Project Manager

Dr Cate Brown Southern Waters Leader Rivers module

Dr Alison Joubert Southern Waters Decision Support System

Dr Jane Turpie Anchor Environmental Leader Socio-economic module

Dr Barry Clark Anchor Environmental Leader Estuary module

Mr. Hans Beuster Emzantsi Systems Hydrology

��

�� !!"��#��!�$��#��%��&'%(�)��*�� '��(��)��$��#��+UNEP)

�� )��!��.��#��&��!��#��&��+IWMI)

Team

2PANGANI RIVER SYSTEM

University of Dar es Salaam Institute of Marine Sciences

Tanzanian Environmental Flow Assessment Team

Dr Benaiah Benno University of Dar es Salaam Fisheries Ecology

Dr. George Lugomela Ministry of Water and Irrigation Hydrologist

Ms Lilian Kukambuzi National Environmental Marine Ecology Management Council - NEMC

Mrs. Dotto Salum Intitute of Marine Sciences Marine Ecology

Mr. Aloyce Hepelwa University of Dar es Salaam Socio-economics

Mrs. Eudosia Materu Ministry of Water and Irrigation Water Quality

Mrs. Lulu Tunu Kaaya University of Dar es Salaam Freshwater ecology

Eng Ingonya Nkuba Ministry of Water Engineer/Economist

Mr. Frank Mbago University of Dar es Salaam Botany

Ms Arafa Maggidi Pangani Basin Water Board Environment

Mr. John Mbaga Pangani Basin Water Board Hydrology Technician

Mr. Erasto William Pangani Basin Water Board Driver/Logistics

Mr. Moses Chillah University of Dar es Salaam Enumerator

Mrs. Kanasia Malisa University of Dar es Salaam Enumerator

Mr. Myige Busumba University of Dar es Salaam Enumerator

Mrs. Dorothy Mungure University of Dar es Salaam Enumerator

Mr. Rustis Bernard University of Dar es Salaam Enumerator

Mr. Shedrack Wililo Sokoine University of Agriculture Enumerator

Mr. Bwagalilo Fadhili University of Dar es Salaam Enumerator

Mrs. Evaclotilda Mathew University of Dar es Salaam Enumerator

Mr. Felix Peter Ministry of Water GIS

Philipo Mwakabengele Pangani Basin Water Board Hydrologist


4 PANGANI RIVER SYSTEM

Foreword

The Tanzania National Water Policy (NAWAPO) of 2002 provides a framework for the management of Tanzania’s water resources to meet both goals of socio-economic wellbeing of its people as well as maintaining the ecological integrity of the freshwater ecosystem maintenance. The Environmental Management Act (2004) further stresses the importance of water for the environment by requiring the Basin Water Boards to allocate enough water for ecosystems. The challenge that exists is therefore to balance water allocation to sustainably meet these two goals i.e. water for socio-economic wellbeing (development) ��$�� <�� <��Q�� <� �� #�$ �� this challenge and assist decision makers in water allocation decisions that take into account the balance between development options and environmental considerations.

Since 2005, the Ministry of Water and Irrigation, through the PBWB with technical support from the International ��!�� !�� !��!��"��=�GEF, European Union and IUCN Water and Nature Initiative (WANI) has undertaken a series of studies to �� $��#�$ ��=��<��?� ��Q�� <�� !�� =��<��?� ��?��=?�?�� !� �� !��$�� !�� $��!!�� $��<��#�$�!��$�� $��estuary. The scenarios also indicate how these changes in the river system could affect the people who ��$�� ?� ��Q�� "� �� < Q

The next step would be for Tanzanian experts and the PBWB to undertake an awareness campaign, among a wide variety of stakeholders from local to national level and across sectors, on interpretation of the scenarios. Decision-makers need to seek a preferred scenario, which will describe a desired development pathway and indicate the agreed water-allocation priorities in the basin river system. We expect this output will greatly contribute to the Integrated Water Resource Management and Development Plan of the basin currently under preparation.

It is our hope that this pioneering work that has been done in the Pangani River Basin will be replicated in other basins in Tanzania.

Washington Nyakale MutayobaDirector of Water ResourcesMinistry of Water and Irrigation, Tanzania


Overview of the Basin

The Pangani River Basin is described in the State of the Basin report. In summary, 95% of it lies in Tanzania and the remainder in Kenya. The river starts as a series of small streams draining Mt Kilimanjaro, Mt Meru, and the Pare and Usambara Mountain ranges, which join to create the main Pangani River. From its headwaters to its estuary on the Indian Ocean at the town of Pangani the river is 500 km long. The river changes in nature along the way, from mountain streams through foothills to a mature lower river. Major features of the system are Lake Jipe on the Ruvu tributary, the Kalimawe Dam on the Mkomazi, and Nyumba ya Mungu (NyM) Dam, Kirua Swamps (now virtually eradicated by �� <��!�#�� `��Hale and Pangani Falls hydropower stations, all on the Pangani mainstem.


The mountains create a cool, wet, high-altitude rim around the northern and eastern parts of the basin, with a hotter and drier region of lowlands in the south west. Annual rainfall ranges from more than 2500 mm on Kilimanjaro and Meru to less than 500 mm in the arid lowlands.

There are eight relatively homogeneous socio-economic zones based on land use and how people use the river. These are the Northern Highlands, Eastern Highlands, Swamps and Lakes, Kirua Swamp, Western Arid, South-western Arid, Mesic (wet) Lowlands and Coast. The people in the Western and South-western Arid Zones do not have strong links with the river system and these areas were not considered further in this project. Strongest links with the river are in the Northern Highlands (irrigation) and the Lakes area �� <�Q�


Topographically, the Pangani Basin can be �� \�� _��!!�� !��#�$��>��Kikuletwa, Mkomazi, Luengera and Pangani. Flow is measured using a network of measuring stations, which allow for the further division of the sub-basins into 15 small catchments.

The Pangani Basin Water Board (PBWB)set up a computer model that described the �� !� #�$� �� Q�� \��#�$ ��so that it was possible to see how these have changed from natural over time as dams have been built and croplands expanded.

The model showed that the Mkomazi sub-basin is the most changed, with about 58% �!� �� #�$��!��Q��Kikuletwa sub-basin is next, with 25% of its #�$�� Q�� !�� the dry season for irrigation, when the streams run the risk of drying out. Overall, about 56% of the Basin’s water is used, with much of the ��<��#�� !��being easily available for use. Only about 14% of the overall use consists of diversions from the river to supply irrigation, rural domestic, and urban water requirements. The remaining 42% is reserved for hydropower generation in the lower basin and is therefore not available for use in the upper and middle parts of the basin. If the water requirements for hydropower are excluded, then 90% of other use basin-wide is !��<��Q�� <�� as best estimates because of the gaps in the ��!�� #�$ ��\�� $�� #�$�� < � ��groundwater and the incomplete knowledge on how much water the basin’s people are taking from the river.

��#�$��!��$��=��<�� in the wet season is much less than natural, �� <��!�#�� Q�These release stored water for hydro-power generation throughout the year and, because �� <� ��<��\��\�� #�$ �� #�$ � �� at that time of the year are closer to natural despite irrigation abstractions.

Hydrology of the Basin

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FlFlFlowowo c catata egegory NNaNatuturar ll PrPresent DaDaDay

MeMeM anananan a a aannnnnnnuaual l flflowwow (( ((mimimim lllllllioioiooonsnsnss o o ooff f f cucucucubibbibicc c meememetrtrtrtreseeses ppp perererer yy yyeaeaeaear)r)r)r) 18181 3030 87878787555

LoLow w flflowowwwss s inin w wetet seaeasososonnn n (m(m(m(millilillililionononnssss ofofofof c cc bububiicicic m metres per yeyeararr))) 7070000 282828281111

LoLoLow flflows s inin d ddryryyy s seaeasosos nn (m((m(m(mililillililiono s fof ccububbiic m tetreess peper r yeyey ar))) 97979999 56565660000

Smalall annuala ffloods (number) 9 1

LaLargrge e ininter-anannunualal floodods s (1( iin n 2 2 yryr; ; 5y5yr,r, 11 10 0 yry and 20 yr) All prresesent AlA l absent

�� !�"��#�� $� �� %�� %

��!� #�$ � �� \by-day, season-by-season and year-��\�� #�$� ��<��Q��!!�� !� ��#�$��<��different roles in keeping the river ��Q� ^�� #�� !�� <�� <�� <�� << X� ��<�� #�� #�� <� ��!��<�� !�� X��$� #�$ � �� ;�� trees and reeds along the banks alive. Comparing the natural and present-day #�$� ��<�� !�� !�� !!��;�� !�#�$� ��$ ��$�� #�$� ��<�� <��<� �� helps us to understand how the river ecosystem as a whole might change. �� !�#�� !�� (see table), has resulted in the Kirua Swamps drying out with a reduction in ��$�� Q


Summary of present condition

The present state of the river and its users is described in the State of the Basin Report. In summary, the basin is quite changed from natural, with some areas more degraded than others. The main changes have been to:� ��3��#� – because of dams and diversions

to urban and irrigation areas, with several parts of the system, such as sections of the Kikuletwa, Mkomazi and Luengera Rivers, now drying out for part of the year;

� �� !� �� – caused by bridges, roads, abstraction of building materials, �� <��#�� !�coarse sediments now trapped behind dam walls;

� �� 4��!��" – which has deteriorated due to �� !#�� !�� !�� areas, and dams releasing turbid water low in oxygen;

� the vegetation – with a loss of the protective riparian trees because of human disturbance, and �!�#��<��;��!�#��<X�

� �4�� – a general trend toward loss of diversity and sensitive species, with increases in robust species that could become health pests;

� ��!��", which is declining:�� ;�� |�� $�� ;��

and encroachment by vegetation�� ^$�� !�

#��<�� $��=��<��

releases of water from the hydropower stations

�� #�$��and water quality changes;

�� " in NyM reservoir, which is declining due to the lower water levels as a result of increased abstractions upstream of the �� !�� <�<��X��

�� invasion of exotic plants into the riparian zones �� #�$��<�� !�disturbance.


Most of the river system � � ��$� �� moderately or largely ��Q�

The changes in the river system reduce its capacity to perform functions that are important to people, such as diluting or removing pollutants, storing #�� <�harvestable goods such � � � �� Q� �� means the livelihoods of people living in the basin who depend on the river for water, income and subsistence are being negatively impacted.

It is not easy to know how big this impact has been as there are no comprehensive historic records of how much people used the river in the past. We do know that at present 75% of the people in the basin live near the river system ��!��!�their income from it. The � �� worth about Tshs 5-7 billion, and the total value of river resources about Tshs 9-12 billion.

Any further deterioration in river condition will impact on this present use. It will reduce the ability of households to spread risk and to use the river as a safety net after shocks such as loss of employment or death of a breadwinner.

Site summary of river condition


The map showing “Site summary of river condition” has incorrect colour coding in the State of the Basin report (p.44) and the correct colour coding is provided in this report.

water quality

riparian vegetation

aquatic invertebrates

� �

B: largely natural

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��<��

��

n/a

Integrated Water Resource Management

Rivers are the lifeblood of national economies, and the source of most water for drinking, washing, ��;��<�� $��<�� Q�� $�� $��!�� <��!�#��$�� $�� \��<��<��!�<��$�� <��!��$�� areas of great beauty for recreation, and more.

Through population growth and over-use, most rivers across the world are now in poor condition, and can no longer provide all the �� the past. Water has been taken without realising that the rivers themselves need water in order for them to remain healthy. As they lose condition they change, and this can have many different kinds of costs for humans, such � � �� #��<�� !�infrastructure, increased droughts as the wetlands that store water are destroyed, declines in wild � �� !�treating water once the natural �� damaged.


We now understand that we need to share rivers in ways that allow careful development of their resources without destroying them, or we may lose more than we gain. We need to agree on and then manage an appropriate balance between development and resource protection. This point of balance, sometimes �� <��differ from river to river. We might wish to keep some rivers, such as those running through national parks, in very good condition and so they would need most of their ��#�$��$�� !��\producing areas might be kept in a lower condition as much of their water is needed for irrigation. There is a limit to how far they should be allowed to deteriorate, however – rivers in very poor condition can be health hazards and liabilities in many other ways.

��<��>� ��`��<��>`�� #�� $�$��!��;��<Q�� based on the four Dublin Principles, which state that development, if it is to be sustainable into the future, must address three fundamental issues: environmental integrity, economic wealth and social justice. IWRM seeks to promote economic and social development in a fair way that also safeguards the rivers.


Environmental Flows

Taking better care of rivers, in line with the Dublin Principles, has become a major international concern �� '�� Q��!�� <��!��#�$�� #�$�� most important driver of river health. Once society, through government and stakeholders, has decided �� !��#�$��<��;�� <�� #�$ ��$��Q��?��$��$�� $��$��;��$�$�� #�$��<��

A desired state can be agreed on by considering many different possible states for the river from pristine to �� !��Q�� !��$�� the system could support; if the water supply would be reliable; if the water would be of good quality and suitable to be drunk by people and livestock without health risks; how much cropland could be irrigated; how much hydropower could be generated; and if endangered species would be protected.


Each of these possible states, with its implications, is called a scenario. A scenario is a way of exploring ideas and possibilities for the future. It does not describe what WILL happen to the river and its people, ��$��Z��!��<�� <��expansion of cropland or river rehabilitation, are carried out.

Each scenario starts with use of the hydrological model to produce a description of how the management ��$��!!�� #�$� ��<��Q� �� $� ��#�$� ��<��$��<�� $�� ecosystem, and then how the river change would affect people, both positively – perhaps by use of the water ��<��%�� <�� <�� "��!�� Q

The scenario that represents the most acceptable trade-off between negative and positive impacts describes �� Q�� $��$�� \�!!�� X�� <�� <�� <��Q�Z�� #�$� ��<�� ;�� #�$�!��Q�� _�� be monitored to ensure it is being maintained in the river. Many countries, including Tanzania, now have �� <� ��_��<��#�$�� !��!�� Q


The Pangani Integrated Flow Assessment approach

The aim of the Pangani River Basin Management Project is 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.

?�� !� ��<�� #�$��<�� <�� <��kinds of data needed. Instead both developing and developed countries have had to begin new ways of studying and managing rivers. The Pangani River Basin Management Project recognised that data on the river were sparse and the Team devised ways of using a mixture of Pangani data, international and national understanding of how rivers behave, and local wisdom, to help them make predictions of the likely results of possible future management actions.

Order of water allocation in the original 15 scenarios (1 = top priority, 6 = residual); U = upper basin; L = Lower Basin


Scenario� [Q�`�%� &Q�`�%�� Q�Z��=�� Q�Z��=�� *Q�`�%�� +Q�`�� Q�`�% Agric HEP (Agric) (HEP) health rainfall Agric, -20% (Agric) (Agric) rainfallBasic Human Needs 1 1 1 1 1 2 2Urban 2 2 3 3 3 3 3Agriculture 3 4 4 6 4 4 4HEP 4 3 6 4 6 5 5Rivers 6 6 2 2 2 6 6Climate change n/a n/a n/a n/a n/a 1 1

The PBWB inserted different kinds of management options into the basin hydrology model. One scenario, for instance, inserted extra irrigation areas in any part of the basin where this might be possible. Another scenario kept irrigation at present-day levels but inserted hydropower dams in several additional places. ^�� #�$� ��;� �� <�� $� �� improved, and how this would affect food production and hydropower generation. Others looked at how changing rainfall patterns might affect the basin’s water resources. Fifteen scenarios were created in this way, which took into account projected changes in urban populations and assumed a 30% increase in the �!��!��<��$�� Q��[*� �� !�$�� the water. Water for basic human needs was almost always given top priority (No 1 in the table below) and urban areas given priority 2; both of these are small demands. Hydropower, irrigation or the river itself then followed in some order as priorities 2 to 6. The hydrological model showed that each of the scenarios would �� !!��#�$��<��Q

The effects of climate change on three of these scenarios was then investigated (see page 34). Climate change was given priority 1 in these scenarios, because it would over-ride any human use of water and dictate its availability.

The Pangani water development scenarios


8. Max 9. Max 10. Max 11. Upper 12. Lower 13. Combo 14. Mixed 15. Opt PD � �<��\�'�� {�=��\&'�� {�=��\�'�� [[��[&Q� �� $�� rainfall rainfall rainfall storage storage storage 2 2 2 1 1 1 1 1 3 3 3 2 2 2 2 3 4 5 5 3 U3, L4 U3, L4 U3, L6 4 5 4 4 4 U4, L3 U4, L3 U4, L3 6 6 6 6 6 6 6 6 2 1 1 1 n/a n/a n/a n/a n/a

Order of water allocation in the original 15 scenarios (1 = top priority, 6 = residual); U = upper basin; L = Lower Basin

How the scenarios were interpreted and evaluated

��<��[*� �� $�� !��<��#�$��<��!�� <�� Q�� #�$ �$�� !��$��change the river at each of the sites. Twenty-three important attributes of the river ecosystem were chosen �� $��<��<��<��

�� Q<Q��;�� $��_��Q<Q��%�<�� <�� Q<Q�Tilapia�� _�� Q<Q��;#�� <��Q<Q�$��\��;�<��

]��$��<�� <� ��<�� !�� $��summarised for each of the socio-economic zones, and these were used to make predictions about changes in social wellbeing and the economic value of the basin. Wellbeing was evaluated in terms of percentage change in household income. Changes to the economic value of the system were evaluated both in terms of conventional outputs such as agricultural, natural resource and hydropower production, and in terms of the value of non-marketed ecosystem services provided by the river system. It is important to include this last value because, if left unrecognised, valuable services can be lost due to ecosystem degradation, which �� %�� Q�� <�� <��regulating and cultural services. The non-marketed services considered here were two kinds of regulating �� $�� !��!�$�� !�� Q


Site Name

1 Upper Kikuletwa

2 Lower Kikuletwa

3 Upper Ruvu

4 Lower Ruvu

6 Pangani @ Kirua

7 Lower Mkomazi

8 Lower Luengera

9 Lower Pangani

The river sites

�� <� �!� ��$� �� $�� <�� #�$ � ��<�� $� �� ^�� ^� �� ^^�Q� �� #�$� ��<�� !�� scenario was inserted into the DSS, the knowledge base was used to produce a prediction of how each attribute would change. The DSS detailed how the whole river ecosystem – banks and channel, water quality, plants and animals - was expected to change all along the length of the river system under each of the 15 scenarios. The DSS also housed the Team’s understanding of the social links with the river, using indicators such as household income and wellbeing. Each scenario’s predictions of river change automatically linked through to predictions of social impact. All of these predictions are reported in the project’s Scenario Report. As many of the scenarios �� _��$�� !��$��<��<� Q


Provisioning services

� edible plants and animals

� freshwater� raw materials - wood,

rocks and sand for construction, firewood

� genetic resources and medicines

� ornamental products for

handicrafts and decoration

Regulating services

� groundwater recharge� dilution of pollutants

� soil stabilisation� water purification

� flood attenuation� climate and disease

regulation� refugia/nursery functions

Cultural services

� �� <��

enrichment� aesthetic appeal

� inspiration for books, music, art and photography

� advertising� recreation

Supporting servicesnutrient cycling, soil formation, pollination, carbon sequestration, primary production

Pangani Basin Integrated River Basin Management Decision Support Tool

Socioeconomics tool

Hydrological model

Ecological tool Overall assessment

Rivers Lakes Swamp Estuary

Social wellbeing Economic value6 zones

basin

Ecosystem health

Societal wellbeing

Economic efficiency

Agriculture HEP

Natural resources

Ecosystem services

Household income Intangible

benefits

Our starting point for the Pangani scenarios:the present day

Water allocationsWhere water is scarce, as in the Pangani Basin, some potential users may not be able to obtain as much as they would like. There are many demands for water, for growing food, for generating electricity, for mining and other activities. At the moment, farming is generally <�� Q�

��!�� !��!��<��$��<�� <��$��may be diverted from the river, with most usually taken in the drier �� $�� #�$� � � �� $Q� �� 80,000 hectares of land under irrigation, with most of this being small-scale agriculture.

The generation of electricity by hydropower (HEP) dams is also an important use of water in the basin. HEP dams do not use much water ��<��!�#�$ �� <��<��#�$ �and releasing them during drier times so that a relatively constant and reliable amount of electricity can be produced. The Pangani Basin presently produces about 602 647 MWh per year.

�� !�"��%�>��#�$��<�� !�� $�<��!��Q�� !�� #�$��<��$�� !��;��$��<��`;��"��>�� #�$��<��<�� $�� $��!��!�� Q��<��#�� each year are becoming smaller, partly because some are stored in dams, such as for the main Pangani >��$� ��!��`�� Q��<��#�� Q�

Changes in the river ecosystem�� #�$��\� ��<� �� !�#�$��$��_�� <�� $�� condition. The once-extensive Kirua Swamp in the middle of the system has now almost dried out.

Socio-economic implicationsPoor rural households are obtaining fewer natural resources from the river, but as we do not know the extent of historical use, the social and economic implications of past change are poorly understood.

Agricultural production is presently worth annually about Tsh200 billion, and natural river resources add another Tsh35 billion. HEP production is worth over Tsh2000 billion. Ecosystem �� $�� !�� presently worth about Tsh327 million.


`�>��`��>��!!��<��#�$ ��$��one year)

Mm3 /a = Millions of cubic metres of water per yearWSLF = Wet Season Low Flows (total volume)DSLF = Dry Season Low Flows (total volume)�� [� ��#�� $�� [��<� ��

largest[�&��[�*��[�['��[�&'��#�� <��&�*��['��&'�� X�[�&'��

largestP = Present; A = Absent


Natural flows Site1 2 3 4 6 7 8 9

MAR (Mm3) 142 884 220 947 1830 91 113 1438

WSLF - Volumes (Mm3 /a ) 68 458 107 524 700 29 39 722

DSLF - Volumes (Mm3 /a ) 63 350 98 250 979 44 46 1200

Class 1 - Annual Frequency 1 0 0 3 0 0 1 0




1:2 P P P P P P P P

1:5 P P P P P P P P

1:10 P P P P P P P P


Present flows Site1 2 3 4 6 7 8 9

MAR (Mm3) 63 661 206 897 875 38 105 1241WSLF - Volumes (Mm3 /a ) 23 374 96 494 281 11 39 574DSLF - Volumes (Mm3 /a ) 27 155 87 219 560 13 40 499Class 1 - Annual Frequency 5 2 0 2 0 1 2 0Class 2 - Annual Frequency 3 3 0 3 1 3 7 1Class 3 - Annual Frequency 2 4 3 3 0 2 4 2Class 4 - Annual Frequency 1 4 3 3 0 1 2 21:2 P P P P A P P P1:5 P P P P A P P P1:10 P P P P A P P P1:20 P P P P A P P P

Scenario 1: Maximise AgricultureDescriptionThe scenario describes what could be expected if current growth and development trends continued. Agriculture would be prioritised after meeting the water demands for basic human needs and urban areas. There would nevertheless be less water for agriculture than at present, because the growing urban population would need more water than currently used. Any remaining water after these two needs would be used for HEP generation. If any water was left (the residual), this was allocated to the river ecosystem (the environment).

Details of water allocations in order of priority1. Full Basic Human Needs and urban allocation for

2025 to Arusha and Moshi2. As much water as can be abstracted at a 75%

level of assurance allocated to agriculture 3. The remaining water used to generate HEP4. Environment received residual

$�� !�"��%��%�� 1. �� $�#�$ ��

season (Sites 1- 4 in upper catchment and Site 7 in the Mkomazi River)

2. >��^��+��=��<��>��$��#�$ ��`�� <��!�#�� 3. ]�� $��#�$ �� &+�� Q


Site1 2 3 4 6 7 8 9

MAR (Mm3) 53 415 157 781 571 9 105 904

WSLF - Volumes (Mm3 /a ) 17 269 71 463 246 1 39 420

DSLF - Volumes (Mm3 /a ) 24 66 59 146 301 5 40 344





1:2 P P P P A A P P

1:5 P P P P A A P P

1:10 P P P P A A P P

1:20 P A P A A A P P

Predicted changes in irrigated agricultureIn spite of slightly less water being available, irrigation areas would increase throughout the basin because �!�� !��!�� Q

Predicted changes in hydropower generationOutput would be reduced to 71% of current output.

Predicted changes in the river ecosystem?�� !�� !�#�� %�� !��<��$�� !��<�� !�� `;��"�Q��$�� $�� in conductivity particularly obvious in the Kikuletwa and Mkomazi. Fish would be substantially impacted, with a severe decline of the Tilapia group in the lower Pangani and toward possible extinction in the Lower `;��"�Q��<��!��^$�� #��$��!�� !��&�Q�Overall health of the river system would show a mild decline at most sites, a more noticeable decline in the Kikuletwa and a very severe decline in the Mkomazi. The estuary would further decline in condition to very ��<��Q

Predicted changes in socio-economic conditionsAggregate household income would increase by up to 5% in the Highland areas and very slightly in the Mesic Lowlands. In the remaining zones there would be a decrease in income, particularly in the Lakes Zone where income would decrease by up to 12%. Recreational and spiritual wellbeing among households in the Highlands and Lake areas would decline by about 10 – 30%, with very little change elsewhere. Overall $��<�$��<��!��;� ��$��$�� <��Q��

Predicted changes in economic values There would be a loss of value in terms of ecosystem regulating services, but a gain in terms of direct value added by the natural resources sector. Much larger gains would be obtained through direct value added by the agricultural sector. These gains would be eclipsed by very large losses in the energy sector.


DescriptionThe scenario describes what could be expected if hydropower generation was prioritised to operate at maximum capacity throughout the basin.

Details of water allocations in order of priority1. Full Basic Human Needs and urban

allocation for 2025 to Arusha and Moshi2. Abstraction for agriculture restricted,

particularly in the upper catchment, in order to maximise the amount of water used by Nyumba ya Mungu and Kalimawe Dams for HEP generation.

3. Water that could not be used for HEP generation allocated to agriculture

4. Environment received residual.

Scenario 2: Maximise Hydropower


$�� !�"��%��%�present day1. ^��<�� \ �� #�$ ��

the upper catchment as agricultural demands give way to water needed for the HEP dams

2. ^��<�� \ �� #�$ ��^��in the Mkomazi River and Site 9 in the lower Pangani River

3. �� <�� #�$ ��$��would inundate a greater portion of the swamp

4. Flows into the estuary increase although #��#�$ �� <��

Site1 2 3 4 6 7 8 9

MAR (Mm3) 66 535 184 863 889 29 109 1524

WSLF - Volumes (Mm3 /a) 21 306 74 502 308 3 37 579

DSLF - Volumes (Mm3 /a) 31 139 72 189 523 18 46 780





1:2 P P P P A A P P

1:5 P P P P A A P P



Predicted changes in irrigated agricultureThere would be a major reduction in irrigation area in the Northern Highlands, but little impact in the remaining zones.

Predicted changes in hydropower generationOutput would be increased by 30% over present day.

Predicted changes in the river ecosystem�� #�$ �� {�=�� $�� %��!��the Lower Mkomazi where dam releases would be used downstream for agriculture, resulting in much the same river condition as in the Maximise Agriculture scenario. Water would be less pure, with increases in conductivity particularly obvious in the Lower Kikuletwa and Lower Mkomazi. Fish numbers would substantially increase in the Kirua area and downstream but decline in the Lower Mkomazi with the Tilapia and Labeo�<�� <� ��$�� %��Q��<��!��^$�� #��$��increase from the present 4% of natural to 15%. Overall health of the river system would decline slightly in the Kikuletwa and Ruvu Rivers, and substantially in the Lower Mkomazi. The lower Pangani and estuary would slightly improve in condition.

Predicted changes in socio-economic conditionsAggregate household income would decrease in all but the Estuary Zone. Income would decrease by about 12% in the Lakes Zone, and by up to almost 10% in the Northern Highlands and Pangani-Kirua areas because of losses in agricultural income. There would be no measurable impact on recreational and spiritual $��<� �� "�� !��;� ��$��$�� <�� <��decrease in utility in the Eastern Highlands. There would be a major decline in overall wellbeing in the Lakes �� <�� {�<�� =��<��\��Q�{�� would be slightly better off.

Predicted changes in economic values Changes in environmental quality and function would lead to a loss of value in terms of ecosystem regulating services, but a similar-sized gain in terms of direct value added by the natural resources sector. Much larger losses would be incurred in terms of direct value added by the agricultural sector. These losses would be offset to some extent by gains in the energy sector.


DescriptionThe scenario describes what could be expected if the present amount of water in the various rivers of the basin was re-arranged to provide the best �� #�$� ��<�� !�� Q�Hydropower generation is then given priority use of �� #�$ �� $�� Q

Details of water allocations in order of priority1. Basic Human Needs supply2. >�� #�$� ��<�� [�&��+��

and 9, and at Kirua Swamps and the estuary, � ��<�� !��#�$

3. Allocation of water to Arusha and Moshi toward, but not necessarily reaching, the projected 2025 demand

�� hydropower


4. {��{�=��#�$��_��Q*�m3/s)

5. Agriculture>� ��{��{�=�� <��#�$��_��*��3/s)

$�� !�"� ��%�� %� �� day1. ��$�#�$ �$�� \��

in the dry season – at Sites 1-4 at the top of the basin and in the Mkomazi

2. ^�� #�� $�� \�� $� ��of Nyumba ya Mungu at the Kirua Swamp

3. ]�� $�� #�$ � ��<� �� $�� <��!�� $�� #�� Q

Site1 2 3 4 6 7 8 9

MAR (Mm3) 79 674 214 898 953 40 107 1293

WSLF - Volumes (Mm3 /a) 22 339 88 522 344 10 39 569

DSLF - Volumes (Mm3 /a) 43 253 107 229 546 12 44 571

Class 1 - Annual Frequency 10 4 0 3 5 3 1 1Class 2 - Annual Frequency 5 6 0 3 14 3 8 2Class 3 - Annual Frequency 2 5 3 4 2 3 5 9Class 4 - Annual Frequency 2 4 6 3 0 1 2 21:2 P P P P A P P P1:5 P P P P A P P P1:10 P P P P A P P P1:20 P P P P A P P P

Predicted changes in irrigated agricultureThere would be about 50% decrease in the area under irrigation in the Northern Highlands. The Mesic Lowlands would experience a slight increase in available water.

Predicted changes in hydropower generationOutput would be increased by 6% over present day.

Predicted changes in the river ecosystem��<�� !� #�$ �$�� <�� #��Q��_��<� �$�� #��<��$�� $�� %!�� and Tilapia particularly in the Lower ��;��$��$��=��<��Q��\#��<��^$��$��%��&&��!�� [*��!�� Q�� $�� <��in condition.

Predicted changes in socio-economic conditionsAggregate household income would increase by about 10% in Pangani Kirua. In the Northern Highlands and Lakes Zones it would decrease by up to 15%. There would be a marked decline in spiritual wellbeing ��<�� ;��Q�{�� "�� $�� !!�� <�� !��wellbeing ,but there would be an improvement in the Pangani Kirua area. The Mesic Lowlands and Estuary would be unaffected.

Predicted changes in economic value�� <��$�� <�� $�� $�� <��loss. Ecosystem regulating services would increase by a small amount. Gains in HEP value outweigh the losses in the other sectors, leading to an overall gain.


DescriptionThe scenario describes what could be expected if water was allocated primarily for improving the health of the river ecosystem, with only Basic Human Needs allocations receiving a higher priority. Existing infrastructure such as dams was taken into account but present operating rules were not. The presence of infrastructure limits the degree to which river health could be enhanced.

Scenario 5: Maximise river health


Details of water allocations in order of priority1. Supply of water for BHN2. >�� #�$� ��<�� !�� %�� <� ��

health at river sites 1, 2, 3, 4, 6, 7, 8 and 9, and at Kirua Swamp and the estuary.

3. Allocation of water to Arusha and Moshi toward, but not necessarily reaching, the 2025 demand.

4. Any remaining water abstracted at a 75% level of assurance for agriculture

5. >��#�$ �\�� #�$ �- used to generate HEP.

$�� !�"��%��%�� day1. ��$� #�$ � $�� \��

particularly in the dry season : at Sites 1-4 at the top of the basin and in the Mkomazi

2. Floods would be re-instated downstream of Nyumba ya Mungu at the Kirua Swamp to a greater extent than in Scenario 4

3. �� !� !�� $��#�$ �reaching the estuary in the dry season

Site1 2 3 4 6 7 8 9

MAR (Mm3) 102 674 214 898 953 50 105 1277

WSLF - Volumes (Mm3 /a) 30 339 88 522 369 26 39 574

DSLF - Volumes (Mm3 /a) 56 253 107 229 414 13 40 499





1:2 P P P P P P P P

1:5 P P P P P P P P


1:20 P P P P A P P P

Predicted changes in irrigated agricultureThe area under irrigation would decrease in the Lakes, Northern Highlands and Mesic Lowlands, but remains relatively unchanged in the Eastern Highlands. Overall irrigation area would be about 69% of present.

Predicted changes in hydropower generationOutput unchanged.

Predicted changes in the river ecosystemThe changes in river and estuary health would be much the same as under Scenario 4, but with some mild additional improvement. Further enhancement of the ecosystem is not possible because of the existing dams on the system.

Predicted changes in socio-economic conditionsAggregate household income would decrease by up to 19% in the higher zones. There would be slight increases in the other zones of up to 9% (Pangani Kirua). There would be a large increase in the recreational and spiritual wellbeing experienced by households in the Northern Highlands, and a decline in the Lakes Zone. Overall wellbeing would decline in the Northern and Eastern Highlands and would decline in the Lakes Zone by almost 15%, but would increase by 7% in Pangani-Kirua.

Predicted changes in economic valueChanges in environmental quality and function would lead to a slight gain of value in terms of ecosystem ��<��<� �� Q�{�$��$�� <�� !��{�=�and agriculture, which would outweigh these gains. The overall impact would be a substantial loss in value mainly because of the decline in agriculture.


DescriptionThe scenario describes what could be expected if the present amount of water in the various rivers of the �� $� ��\��<�� #�$��<�� !��Q��%� ��<��!�� such as dams was taken into account, but present operating rules were not. Additional storage was added in �� $��!� ��#�� do not dry out.

�� additional water storage


Details of water allocations in order of priority1. Basic Human Needs2. ^��!�� !��#�$��

�� !� #�$ � �� condition at river sites 1, 2, 3, 4, 6, 7, 8 and 9, and at Kirua Swamps and the estuary.

3. Allocation of water for Urban/Industrial to Arusha and Moshi towards the 2025 demands.

4. ^��<�� !� �� $�� #�$ � �� catchment: 56 Mm3 storage in the Kikuletwa catchment and a 10 Mm3 storage in the Ruvu River.

5. Any remaining water abstracted at a 75% level of assurance allocated to agriculture.

6. >��#�$ � ��!��#�$ �� <��{�=Q

$�� !�"��%��%�� day1. ��$� #�$ � $�� \��

particularly in the dry season, at Sites 1-4 at the top of the basin and in the Mkomazi

2. ^��#�� $��\�� $� ��of NyM and Kirua Swamps would be inundated to a greater extent than in Scenario 4

3. Less of an abnormal elevation of freshwater #�$ ��

Site1 2 3 4 6 7 8 9

MAR (Mm3) 78 636 214 884 839 39 107 1175

WSLF - Volumes (Mm3 /a) 22 313 88 515 278 10 39 512DSLF - Volumes (Mm3 /a) 42 254 106 234 506 11 43 512Class 1 - Annual Frequency 5 1 0 2 6 2 1 0Class 2 - Annual Frequency 4 5 0 3 15 3 7 9Class 3 - Annual Frequency 2 5 2 4 1 3 4 5Class 4 - Annual Frequency 2 3 5 3 0 1 2 21:2 P P P P A P P P1:5 P P P P A P P P1:10 P P P P A P P P1:20 P P P P A P P P

Predicted changes in irrigated agricultureThe area of irrigation would decrease to 49% of current area in the Lakes, and 60-70% in the Northern Highlands and Mesic Lowlands, but remain relatively unchanged in the Eastern Highlands. Overall irrigation area would be about 69% of present.

Predicted changes in hydropower generationOutput unchanged.

Predicted changes in the river ecosystem��<� � �� $�� ^��$�� <�� $��<�� !� ��Q��$��improvement in river condition and a greater improvement in Kirua Swamp, which would expand to 117% of its present extent. The condition of the estuary would decline very slightly (by 2%).

Predicted changes in socio-economic conditionsAggregate household income would decrease by up to 15% in the Northern Highlands and to a lesser extent in the Eastern Highlands and Lakes, and there may be a slight improvement in Pangani-Kirua. There would be a 20% increase in recreational and spiritual wellbeing among households in the Northern Highlands and no change in the remaining zones. There would be a slight negative impact on overall wellbeing in all of the upper zones, but a slightly positive effect in Pangani-Kirua.

Predicted changes in economic valueThere would be large losses in HEP and agriculture leading to an overall large loss of value. Ecosystem regulating services and natural resources would increase by very small amounts.


�� $��$�!��!��$�� $�� $��compare with present-day conditions. Prioritising water allocation to maximise agriculture (Max Agric) would lead to a worsening in the ecological health of most parts the basin, whilst maximising hydropower generation would result in it remaining much as at present (Max HEP). Scenarios that focus on the pattern �!�#�$ ��Z�� \��#�$ ��%�� <�� ecological condition. Increasing water storage capacity in the basin (Scenario 15) does not have ecological �� !��=��<��>��$��`Q

��%��&��

��

Summary of the development scenarios


Present Day

1. Max Agric

2. Max HEP

4. Opt PD + HEP

5. Max river health

15. Opt PD Add Store

Urban/Industry (Mm3 /a water) 31.1 54.7 54.7 53.6 50.9 53.6

Irrigation (Mm3 /a water) 1042 1032 634 558 497 591

HEP (103 MWh.y-1) 603 428 783 639 601 580

NyM Lake area (ha) 104 66 60 65 64 94

Kirua flooding (% of natural) 5 2 15 22 25 17

Fish catch @ Kirua (t) 133 53 389 549 643 154

Overall change in river health (%) 0 -4.3 -0.3 1.4 2.5 0.7

Scenario/Site Present Day 1. Max Agric2. Max HEP

4. Opt PD + HEP

5. Max river health

15. Opt PD Add

Store

Upper Kikuletwa B/C C C B/C B/C C

Lower Kikuletwa D D D D D D

Upper Ruvu C/D D D C/D C/D C/D

Lower Ruvu D D D D C D

Pangani at Kirua C C C/B B/C B B

Lower Mkomazi C/D D/E D C/D C C/D

Lower Luengera C C C C C C

Lower Pangani C C C C C C

Estuary D E C C C D

A Natural B Largely natural

C Moderately modified

D Largely modified

E Highly modified

F Completelymodified

1. M

ax A

gric

2. M

ax H

EP

3. O

pt P

D (

Agr

ic)

4. O

pt P

D +

HE

P

5. M

ax ri

ver

heal

th

6. M

odifi

ed ra

infa

ll

7. M

ax A

gric

, -20

%

rain

fall

8. M

ax A

gric

, -30

%

rain

fall

9. M

ax H

EP

, -20

%

rain

fall

10. M

ax H

EP

, -30

% ra

infa

ll

11. U

pper

bas

in

stor

age

12. L

ower

bas

in

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age

13. �

��

�[[�

��

12.

14.

Mix

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its

15. O

pt P

D A

dd

stor

age

Socially, maximising agriculture leads to a gain in agricultural income, but at the expense of hydropower production and ecosystem services, with an overall loss in economic output from the basin. The other four scenarios lead to losses in agricultural production, but where hydropower production is high the overall �� \$��<�� <��Q�

Gain/loss in value compared to Present Day (Tsh millions per year)

There are trade-offs involved in every scenario – something is gained and something lost. The overall ��<��$� ��$ �� !��(economic, social and ecological) .

Economic outputs were generally the most sensitive, with differences between scenarios frequently being greater than 20%. Social wellbeing within the basin changes negatively under most scenarios, but by a relatively small percentage.

Expected overall degree of ecological, social and economic change under all scenarios analysed


Present Day 1. Max Agric 2. Max HEP4. Opt PD +

HEP5. Max river

health15. Opt PD Add Store

Hydroelectric Power 2 380 642 -606 842 547 991 118 225 -4 037 -75 998Agriculture 202 391 15 540 -38 871 -59 077 -62 798 -51 778Natural Resources 34 809 175 -516 -15 661 11Ecosystem services 327 -91 183 250 322 5Total 2 618 170 -591 218 508 788 59 383 -65 852 -127 759% change -22.58 19.43 2.27 -2.52 -4.88

-80-70-60-50-40-30-20-10

0102030

% c

hang

e fro

m c

urre

nt

Ecosystem Integrity

Social well-being

Economics

Effects of Climate Change


The threat of climate change is increasing, and with it will come changes in temperature, rainfall and water availability. Using predictions from state-of-the-art models, three of the water development scenarios (Max Agric, Opt PD HEP, and Opt PD with storage) were compared to predict their impacts with and without climate ��<�Q� �� <�� !� �� #�$ � !�� $�� for changes in rainfall, and then the order of priorities in water allocation remained the same as for the corresponding scenarios without climate change.

Compared to the same scenarios without climate change, the climate change scenarios predict a reduction in ��$��!�� <��{�=Q�� #��<��!�� $�� Q

Status of some of the key descriptors with and without climate change (CC)

Ecological condition with and without climate change (CC)

Scenario/Site 1. Max Agric 16. Max Agric (CC)

4. Opt PD + HEP

17. Opt PD + HEP(CC)

15.Opt PD Add Store

18. Opt PD Add Store

(CC)

Upper Kikuletwa C C B/C B/C C C

Lower Kikuletwa D D D D D D

Upper Ruvu D D C/D C/D C/D C/D

Lower Ruvu D D D D D D

Pangani at Kirua C C B/C B/C B C

Lower Mkomazi D/E D/E C/D C/D C/D C/D

Lower Luengera C C C C C C

Lower Pangani C C C C C C

Estuary E E C C D D

1. Max Agric

16. Max Agric(CC)

4. Opt PD + HEP


15.Opt PD Add

Store

18. Opt PD Add

Store (CC)

Urban/Industry (Mm3 /a water) 54.7 54.7 53.5 49.7 53.6 51.9

Irrigation (Mm3 /a water) 1032 946 558 469 591 505

HEP (103 MWh/a) 428 414 639 611 580 554

NyM Lake area (ha) 66 64 65 64 94 88

Kirua flooding (% of natural) 2 3 22 20 6 6

Fish catch @ Kirua (t) 53 87 549 502 154 149

Change in river health % (change from present day) -4.3 -4.9 1.4 1.1 0.6 -0.1


Whereas there was an overall economic gain under the Opt PD HEP scenario without climate change, climate change leads to losses in overall economic outputs under all three water development scenarios. This overall picture is mainly driven by the reduction in HEP outputs compared with the situation without climate change. With or without climate change, gains in HEP value are only experienced under Opt PD with HEP. Agricultural outputs are also reduced, such that gains under Max Agric are reduced, and the losses under the other scenarios are exacerbated. Likewise, the values derived from natural resource harvesting and ecosystem services are reduced under climate change in all three cases.

Gain/loss in value (Tsh millions per year)

�� <��$� ��$ � ��<��$��<�� !�� three major sectors, with all three scenarios showing a worse situation than present day and than the same scenarios without climate change. The Opt PD + HEP scenario (number 4) remains the one with the least negative impacts, even under climate change.

Expected overall degree of ecological, social and economic change under all scenarios analysed

1. Max Agric 16. Max Agric (CC)

4. Opt PD + HEP


15. Add Store OPT

PD

18. Add Store OPT

PD(CC)

-30-25-20-15-10

-505

10152025

% ch

ange

fro

m c

urre

nt

Ecosystem Integrity

Social well-being

Economics

1. Max Agric

16. Max Agric (CC)

4. Opt PD + HEP


15. Add Store OPT

PD

18. Add Store OPT

PD(CC)

Hydroelectric Power -606 842 -657 496 118 225 26 762 -75 998 -161 735

Agriculture 15 540 2 611 -59 077 -77 050 -51 778 -69 738

Natural Resources 175 -216 -15 -151 11 -47

Ecosystem services -91 -85 250 211 5 0

Total -591 218 -655 186 59 383 -50 229 -127 759 -231 520

Implementation of the desired state and its � �� %� ��!�"�

��!!�� !��#�$�� !��<�� !�$��<��#�$�� <��!�� <�� Q��$�� !�$��$� ��achieve truly sustainable use of rivers, we have to look at a much wider and more complex set of issues and this will take quite a long time. Adjusting water management to achieve sustainability could well take one, two or maybe three decades, even where the political will, funds and technical skills exist.


Activities necessary for sustainable use of rivers

Development of appropriate policy, legislation and international basin agreements

Re-organisation of institutions to meet new laws

Structured and continual engagement with stakeholders at every stage of the process

��!�#�$�� <�� $��as economic ones

Design of new kinds of infrastructure and operating rules to deliver and monitor environmental #�$

Development of local regulatory mechanisms for licensing or re-licensing water use

Creation of awareness among governments and other stakeholders

Continual investment in research and capacity building

`��!��#�$��

`��<��!� ��#�$�� <�� !�necessary

Following the technical work already completed in this project, focus now switches to stakeholders and government. If a scenario could be agreed on, then the next sequence of technical work could begin. This would be to help lay out a basin water-management plan, which would guide future decisions ��$�� <��<��$��$��;��!��#�$ ��being maintained in the river, and the agreed desired river state is being achieved.

Conclusion

Some important principles came from the Pangani River Basin Management Project, including the following:

�� !��#�$��<��!��<� �� $��<�� Q�=� ��<�� <��!��Q��<��<��$�� ecological and social issues in a structured and agreed way into water-resource management plans so that the future implications can be understood and an acceptable future chosen.

�� \$��<��#�$�� <��!�$��\�� planning, so that a fair trade-off between development and river protection can be agreed. This should then guide all future water-management decisions for the river.

�� It is never too early to get started – there is always some knowledge on the river and its people, and #�$\� � �� %� �� ;��$��<��$�;�� !��!��to stakeholders and decision makers.

�� !��<�� #�$�� <��%�� ;Q�Government, scientists, and stakeholders including local subsistence users of the river need to work together as a team to achieve truly sustainable use of the river.


Way forward

The stakeholders of the basin now have available considerable insights into the implications for them of alternative water-management strategies. These strategies will affect their future livelihoods, wellbeing, and local and national economies. They can choose to manage that future, or just let it happen, as has happened globally in the past.

Climate change and population growth will further affect water availability in this already water-stressed basin, ��$��;��<�$��<�� <�� !��!��Q�^� �� of water can only be achieved if the trade-offs between development and resource protection are carefully weighed up and a future chosen that all stakeholders can understand, see as fair and wish to adhere to. It is better to choose a long-range future together and manage to achieve it, than to react to each day-by-day emergency with no master plan.

��<��!��<�� !�� Q�� $��also have to be made between levels of hydropower generation, crop production and ecosystem health, as not all of these can be sustained simultaneously at their highest possible level. It is not economically or socially wise to assume that the natural ecosystem is dispensable; instead some level of protection should be afforded it, in recognition of its status as one of the three pillars of sustainable use.

��=��<��?� ��Z!��"��!� �� ;�� basin’s stakeholders further explore the 18 scenarios, or to investigate new ones, as they seek the optimum trade-off between development and resource protection for this basin. The Pangani Basin has strong social and governance structures that can help identify this desired trade-off point and drive the process of setting up a basin-wide water-allocation plan. Appropriate infrastructure design, operating rules and monitoring for compliance would be important parts of ensuring success of the basin plan.

�� $��;�� "�� $��\�� <� ��management among African countries. It would join a growing international movement towards building economic and social resilience based on sustainable management of its natural water resources.


Further reading�� `Q��?��<;��Q��^��|Q� �� Q�&''�Q�]��$Q�� !�� #�$ Q� ��

Gland, Switzerland and Cambridge, UK. 118 pp.

King, J.M. and Brown, C.A. 2010. Integrated Basin Flow Assessments: concepts and method development in Africa and South-east Asia. Special Issue of Freshwater Biology 55(1):127-146.

Postel, S. and Richter, B. 2003. Rivers for life: managing water for people and nature. Island Press, London. 253 pp.

King, J. and Pienaar, H. in press. Sustainable use of South Africa’s inland waters: A situation assessment of Resource Directed Measures 12 years after the 1998 National Water Act. Water Research Commission, Pretoria.

Reports of the Pangani River Basin Flow Assessment Initiative*!!��!��!��$��#��

�� Hydrology of the Pangani River Basin, volume 1. 2006. +57 pp

�� Basin Delineation Report. 2006. 51 pp.

�� Scenario Selection Report. 2006. 22 pp.

�� River Health Assessment. 2006. 185 pp.

�� Estuarine Health Assessment. 2006. 115 pp.

�� Socio-economic Baseline Assessment. 2006. 58 pp.

�� Specialist Reports:

1. {Q�`;��=Q��Q��Q��!��<�� 2. G. Kahyarara. Macro-economic model of the Pangani River Basin3. ZQ�{��;��`Q�Q�>��Q�`��^Q>Q�`$��<�Q�]� ��!��

histories and important fisheries of the Pangani River Basin4. �Q=Q��<��^Q��""�Q�{��$��<� ��5. �Q�Q��̂ Q{Q�̀ ;��|Q��=Q`Q��=Q��]Q�Q�̀ ��Q�{��

of Lake Jipe, Nyumba ya Mungu reservoir and Kirua Swamp6. =Q�Q�Q� `�� Q� ��;�� ^�;��Q� �� <�� !� �� =��<�� >�� ?� ��

association with flow regimes7. �� `Q��=Q�� ;�Q�&'['Q��<��<�!��=��<��?� ��

the IWRM planning process.

�� Task 5 Report: an assessment of understanding and knowledge gaps. 2008. 65 pp.

�� Hydrology of the Pangani River Basin, volume 2: development and application of a system model for the Pangani River Basin. 2009. 96 pp.

�� Scenario Report: the analysis of water-allocation scenarios for the Pangani River Basin. 2009. 335 pp.

�� Final Project Summary Report. 2009. 98 pp.


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