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Integrated Flow Assessment for the Luangwa River Zambia: Phase 1 BASIN CONFIGURATION OF EFLOWS BASED ON A RAPID BASIN PLANNING TOOL

THIS REPORT HAS BEEN PRODUCED IN COLLABORATION WITH

ZMREPORT

2018

Written By: Jackie King, Alison Joubert, and Justine Ewart-Smith

Citation: WWF. 2018. Integrated Flow Assessment for the Luangwa River. Phase 1: Basin Configuration of EFlows.

WWF Zambia, Lusaka, Zambia

Design by: Keti Editorial Services

Front cover photo: © WWF

Printed by: Printech Limited

Published in March 2018 by WWF-World Wide Fund For Nature (Formerly World Wildlife Fund), Zambia. Any reproduction in full or in part must mention the title and credit the above-mentioned publisher as the copyright owner.

© Text 2018 WWF

All rights reserved

ISBN 978 2 940529 71 1

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BASIN CONFIGURATION OF EFLOWS BASED ON A RAPID BASIN PLANNING TOOL

March 2018

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Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows

CONTENTSEXECUTIVE SUMMARY 7

1. INTRODUCTION 10

1.1 Background to the project 10

1.2 Role of aquatic fauna in this assessment 10

1.3 Terms of reference 11

1.4 Key deliverables and report layout 11

2. THE CONCEPT 12

3. DEFINITION OF TERMS USED IN THIS DOCUMENT 14

3.1 Present Ecological State (PES) 14

3,2 Environmental Flows (Eflows) 14

3.3 Flow-Driven Ecological Condition (FDEC) 14

4. APPROACH 14

5. SITE SELECTION 15

6. HYDROLOGICAL ANALYSES 17

6.1 Natural monthly flows for all 39 sites 17

6.2 Natural daily flows for the 21 eflows sites 17

6.3 Rules for determination of FDEC for any flow regime of interest 17

6.4 Analysis of current dry-season flows 19

7. COMPILATION OF THE EFLOWS TABLES 25

7.1 Calculate the hydrological index (hi) for each of the sites 25

7.2 Separate natural low- flow and inter-annual flood volumes 27 7.3 Calculate inter-annual floods for all condition categories 28

7.4 Calculate low flows and intra-annual floods for all FDEC categories 30

7.5 Summarise overall eflows requirement for each Eflows site 33

7.6 Calculate eflows for sites with higher than natural dry-season flows 35

7.7 Import eflows tables into configuration model 35

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8. THE EFLOWS BASIN CONFIGURATION MODEL 36

8.1 Introduction 36

8.2 Assessment of scenarios and the achievement of targets 41

8.3 Translation of FDEC back to overall ecological condition (EC) 42

9. SCENARIO SELECTION AND ANALYSIS 45

9.1 Scenario 1: baseline – the existing situation 45

9.2 Scenario 2: suggested non-negotiables 47

9.3 Scenario 3: eastern province water supply dams 49

9.4 Scenario 4: muchinga province small dams 52

9.5 Scenario 5: hydropower 54

9.6 Scenario 6: combination of scenarios 2 to 5 57

9.7 Comparison of scenarios and interpretation of results 59

10. USING THE BASIN CONFIGURATION MODEL 65

11. CONCLUSION 67

12. RECOMMENDATIONS 68

12.1 Prepare for hand over 68

12.2 Training and further scenario analysis 68

12.3 Field data and enhanced modelling 68

13. REFERENCES 69

APPENDIX A 70

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This document is number 12 in a series of reports produced in Phase 1, in the series:

01 Inception Report02 Luangwa Basin Division 03 Water Resources04 Hydrology05 Hydraulics06 Fluvial Geomorphology07 Water Quality08 Vegetation09 Invertebrates and Fish10 Mammals, Birds and Herpetofauna11 Resource Economics and Sociology12 Basin Configuration of Eflows based on a Rapid Basin Planning Tool

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The EFlows Basin Configuration Model is an Excel-based tool designed for a first, low-resolution assessment of the implications of water resource developments on a basin’s river ecosystem. It can be used to provide a first insight into how development in one part of the basin could impact the

river system, and thus water resources, in other parts.

Developments such as an irrigation area or dam can be inserted in a location of interest in the basin, and a rapid estimate made of their impact on the flow regime and ecological condition of the nearest downstream site and therefore on those of others further downstream.

The tool helps develop an understanding of where in the basin future water resources could be located and where they should perhaps be avoided if they would conflict with other aspirations for the basin. It should not be used for detailed project planning (location, design, operation) of a new water resource development.

The model, which can be used where data are sparse, was set up for the Luangwa Basin. Its inputs were all coarse estimates with varying levels of authentication. These inputs were:• Daily and monthly hydrological simulations for 21 EFlow sites and 18 hydrological sites across the basin, and linked analyses;• An estimate of Present Ecological Condition for the 21 EFlows sites;• Tables of the monthly percentages of natural flow needed to maintain the ecological conditions A (pristine) to E (severely degraded) at each site;• A selection of scenarios chosen to illustrate different possible futures for the basin under different development options;• Estimates of future flow and ecological conditions linked to each of these developments.

In addition to the present-day scenario, five water-resource scenarios were chosen to represent possible futures for the Luangwa Basin. The model predicted the flow condition and ecological condition at each EFlow site under each scenario. The conditions were presented as a symbol, from A (pristine) to E (severely changed) for each site under each scenario.

EXECUTIVESUMMARY

ALL DATA AND INFORMATION

WERE COLLATED INTO A LIBRARY

USING A REFERENCE

MANAGEMENT SYSTEM KNOWN

AS MENDELEY

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The maps below compare present flow conditions with those of Scenario 6, which includes a range of hydropower and other small dams. All the assumed developments under Scenario 6 were placed on tributaries that then show varying levels of decline from a natural flow condition, while the mainstem remains in a near-natural flow condition until close to its confluence with the Zambezi (pale green circle at bottom of map on right).

Figure A

The 21 EFlows sites (e.g. 15.2) and 18 hydrological

sites (e.g. HS14) for the Luangwa Basin

Figure B

Existing flow condition (left) and predicted flow

condition under Scenario 6 (right) for each of the

EFlow sites

The model also predicts the related ecological condition of the river, which may or may not be the same as the flow condition. The ecological condition could be lower if, for example, pollutants were being discharged into the river, as well as there being a change in flow. The maps below, when compared with the maps above, show that under the present condition, and under Scenario 6, the ecological condition is lower than the flow condition, suggesting degradation through other human interventions as well as through flow modification.

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Figure C

Estimated existing ecological condition (left)

and predicted ecological condition (right) for each of the EFlow sites under

Scenario 6

Parts of this document provide background to the running of the EFlows Basin Configuration Model, such as an hydrological analysis, which includes an analysis of existing dry-season flows for all EFlow sites (Section 6); a description of how the EFlow tables were compiled (Section 7); a description of the model (Section 8); and an explanation of how the scenarios were selected and set up in the model as well as the results (Section 9).

It is recommended that the model, which is in a developmental stage, be finalized for the Luangwa Basin, for handover to WWF and WARMA, and a short simple User Manual based on this document be written. A second part of such a document could be a generalized set of activities to guide setting up of the model for any other basin.

It is also noted that tools such as this model often trigger a further round of investigations of development options not considered in the first application. These might include moving the scenario dams to a different part of the basin, for instance, or changing the scale, location or crops of contemplated irrigated agricultural expansion. To aid such exploration, it is recommended that potential users of the model be trained to use it and interpret its outputs. This should be a fairly easy and quick set of training for, for instance, a hydrologist with some ecological experience or a river ecologist with experience in hydrology and modelling.

The assumptions made in setting up this model for the Luangwa Basin are many and varied, and are explained throughout the document. Phase 2 of the Integrated Flow Assessment for the Luangwa Basin should include a structured programme of field data collection; improved hydrological modelling; on-site assessment of the PES of each site; and setting up of an hydraulic model for the mainstem floodplains associated with the South Luangwa and/or North Luangwa National Parks.

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1.1 BACKGROUND TO THE PROJECT

WWF, in collaboration with Zambia’s water management agency, WARMA, has launched a new initiative to address integrated flow management of the Luangwa Basin as part of a wider Zambezi flows programme. The aim is to provide support to WARMA for the

development of the Luangwa’s catchment management strategy. A central part of the strategy will be agreeing on future flows for the river system. These flows are widely referred to as Environmental Flows or EFlows.

The Luangwa EFlows Assessment is planned to take place in two phases. Phase 1 consists of locating and synthesising all available information on the Luangwa Basin, leading to an initial formal division of the basin into homogeneous biophysical and social areas. Another major part of Phase 1, which is the subject of this report, is a rapid desktop estimate of EFlows that would support an A (pristine) to D (largely modified) ecological state in the river at points across the basin, as an input to basin development plans.

Building on this, Phase 2 will be a detailed EFlows Assessment through analysis of several potential development or other management options. Its purpose will be to provide a tool that can aid government and stakeholder discussions and decisions regarding the future of this important basin.

1.2 THE ROLE OF BASIN CONFIGURATION IN THIS ASSESSMENTThe Luangwa River system is largely unregulated and an EFlows Assessment for this basin has never been undertaken. For such situations, King (2012) recommended that a rapid, coarse EFlows Assessment should be carried out, the results of which could guide basin planning until a more comprehensive EFlows exercise could be completed. The purpose of such a coarse assessment for the Luangwa River system would be to:

• Create awareness that water-resource development in one part of the river basin will have repercussions for other parts of the basin, thus requiring a basin-wide approach to developing water resources and managing river flows;• Promote the concept that pro-active planning of development of the river’s water resources will facilitate efficient management and decision making for the basin;• Respond to the requirements of Zambia’s Water Resources Management Act (Act No. 12 of 2011) for an allocation of water to sustain the river ecosystems;• Provide a preliminary assessment of what that amount of water might be for selected sites along the Luangwa River system.

This report addresses the rapid assessment, here called an EFlows Basin Configuration.

1. INTRODUCTION

THE FLOW REGIME IS A FUNDAMENTAL

PART OF RIVERS

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1.3 TERMS OF REFERENCETask 1: Set up the EFlows Basin Configuration ModelSet up the EFlows Basin Configuration Model using the hydrological model outputs created by the team’s hydrologists.

Task 2: Select sites and complete hydrological analysesComplete the selection of sites initiated at the Basin Division workshop, for the EFlows Basin Configuration exercise, and ensure monthly and daily flows are simulated for all sites. Calculate the Hydrological Index for each site.

Task 3: Compile an EFlows table for each site and import into the EFlows Basin Configuration ModelCompile an EFlows table for each site that indicates the monthly volumes recommended to support that river reach in an A/B, B, B/C, C, C/D and D ecological condition. Import these tables into the EFlows Basin Configuration Model.

Task 4: Select a set of scenarios to illustrate the model outputSelect six combinations of possible future flows across the basin to illustrate different potential futures for the basin, using existing and possible future water resource developments in the basin as a guide.

Task 5: Run the scenarios through the EFlows Basin Configuration Model and report on the outcomeRun the six scenarios through the model. Write a report of the findings.

1.4 KEY DELIVERABLES AND REPORT LAYOUTThis report is the key deliverable. After this introduction, Section 2 outlines the concept, Section 3 explains some of the technical terms used, and Section 4 provides an overview of the approach used to complete the basin configuration exercise. Sections 5 to 8 explain the process in detail. Section 9 gives the results of the scenario analysis, and Sections 10 to 12 provide a summary and recommendations.

The EFlows Basin Configuration Model is also potentially a key deliverable in Phase 2. Once refined, it will be provided, already set up, to illustrate the scenarios presented in this report.

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There is no magic amount of water that automatically keeps a river ‘healthy’: as water is abstracted from the river or its flow pattern changes, it will start to degrade from its natural condition. It thus becomes a choice of society how much river degradation people are willing to accept in order to gain the benefits that water-resource development could bring. That is why the fourth bullet in Section 1.2 states what the

amount allocated for river maintenance ‘might be’ – that amount and its corresponding river condition are a societal choice. The process explained in this report illustrates how different water resource options can be rapidly analyzed, in order to help people achieve a first insight of what that choice could be and create awareness of its implications.

WWF’s Luangwa Basin EFlows project follows the left arm of the graphic in Figure 2.1, with the rapid assessment taking place in Luangwa EFlows Phase 1 and the detailed (holistic) assessment in Phase 2. If desired, EFlows for reaches downstream of existing hydropower dams in the basin could be assessed via the right arm of Figure 2.1.

2. THECONCEPT

Figure 2.1

Overview of the suggested EFlows implementation process for the Zambezi

River Basin (King, 2012)

In the rapid EFlows Basin Configuration exercise it is recognised that rivers can be managed to be maintained at different levels of ecological health (or Present Ecological State – PES) from Category A (natural) to Category E (critically modified) (Table 2.1). One of the major drivers of this state of health is the river’s flow regime, which can also be categorised in terms of its deviation from natural on a scale of A to E (the flow categorisation is explained in Section 6). The two categorisations have to be separated because the ecological condition of a river can be different to that expected from the

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state of its flow regime through impacts not related to flow. The flow regime could be essentially natural, for instance, while overall river health could be quite low due to agriculture runoff (pesticides, fertilisers, soil erosion), bank clearance or effluent disposal.

Ecological category Description of the habitat

A Unmodified. Still in a natural condition.

B Near natural. A small change in natural habitats and biota has taken place but the ecosystem functions are essentially unchanged.

CModerately modified. Loss and change of natural habitat and biota has occurred, but the basic ecosystem functions are still predominantly unchanged.

D Largely modified. A large loss of natural habitat, biota and basic ecosystem functions has occurred.

E Seriously modified. The loss of natural habitat, biota and basic ecosystem functions is extensive.

F

Critically modified. The system has been critically modified with an almost complete loss of natural habitat and biota. In the worst instances, basic ecosystem functions have been destroyed and the changes are irreversible.

Table 2.1

Definitions of the Present Ecological State

(PES) categories (after Kleynhans et al. 2008)

As development proceeds in a basin, flow regimes and river health change in ways that we increasingly understand and can predict. The EFlows Basin Configuration Model provides a rapid assessment of how development scenarios of interest to governments and stakeholders could manifest across the basin.

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3.1 PRESENT ECOLOGICAL STATE (PES)The PES is the overall present ecological condition of a river site whether driven by flow or non-flow related impacts on a scale from A (pristine) to E (severely changed), with E being generally recognized as an unacceptable level of ecological degradation. A first, very coarse estimate of PES was made for various parts of the Luangwa Basin in the Basin Division workshop, but it was recognized that there was very little information on which to base these estimates and they should be revised during the fieldwork linked to Phase 2.

3.2 ENVIRONMENTAL FLOWS (EFLOWS)The monthly volumes of flow required to support a specific ecological condition.

3.4 FLOW-DRIVEN ECOLOGICAL CONDITION (FDEC)The FDEC, on a scale from A to E, is an expression

of the expected level of ecological condition that could be supported by a flow regime, all else being equal (i.e. with no other interventions causing a loss in ecological condition).

3. DEFINITION OF TERMS

USED IN THISDOCUMENT

As long as the relevant hydrological information is available (Section 6), it has become possible to tabulate for any point in a drainage network in southern Africa the FDEC as monthly volumes of

flow that would support each ecological condition. It is not possible to decipher from these monthly volumes the recommended daily flows for maintaining specific river attributes, but the monthly amounts are useful for coarse-scale basin planning. An EFlows table was created for each EFlows site in the Luangwa Basin, which showed the monthly volumes of water that would constitute a FDEC category A to E. These tables were entered into the Basin Configuration Model so that scenarios could be explored.

Each scenario required a decision about which FDEC category the sites relevant to the scenario would be held at. One scenario, for instance, might require all the rivers within National Parks to be held at least at a Category B FDEC. The model then determines which FDEC levels would be possible at the remaining downstream sites once these requirements are met and thus how much water would or would not be available in different parts of the basin for development.

Sections 5 to 9 describe the process.

4. APPROACH

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A Basin Division workshop was held in Lusaka on 9-10 December 2015, attended by 10 members of the EFlows team and 12 other specialists from WARMA, DWA, ZESCO, Lunsemfwa Hydropower Company, ZAWA and WWF. Its main objectives were to:

• Divide the Luangwa Basin into relatively homogeneous biophysical and social areas;• Select one or more sites within each to represent its/their area in the analyses;

• Agree on the Present Ecological State (PES) of each site and the key drivers of ecological condition.

Details of the workshop and its findings are given in Report Number 2 in this series. Of relevance here are the division of the basin by the delegates into 15 homogeneous units (HUs) (Figure 5.1), the allocation of 21 EFlows sites representative of these HUs, and the estimated PES agreed for each site (Table 5.1) based on perceptions from delegates at the workshop of these very remote areas. Actual field data are needed for verification.

5. SITESELECTION

Figure 5.1

The 21 EFlows sites selected at the December 2015 workshop (Report 2

in this series)

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EFlows Site River Name HU PES

1.1 Lusiwasi 1 B

11.1 Lukusashi 11 B

2.1 Luangwa 2 B/C

8.1 Luangwa 8 B

9.1 Luangwa 9 B

8.2 Luangwa 8 B

10.1 Luangwa 10 B/C

7.2 Lusiwasi 7 A/B

3.1 Luwumbu 3 B

12.1 Lunsemfwa 12 C/D

12.2 Lunsemfwa 12 C/D

2.2 Msandile 2 B/C

6.1 Msandile 6 C

15.1 Lunsemfwa 15 B/C

4.1 Lundazi 4 C

4.2 Lundazi 4 C

5.1 Lukusuzi 5 B

15.2 Lunsemfwa 15 B/C

7.1 Munyamadzi 7 B

1.2 Munyamadzi 1 B

14.1 Mwomboshi 14 C

Table 5.1

Location of the 21 EFlows sites by HU and river and

their estimated Present Ecological State (PES)

An additional 18 hydrological sites required by the EFlows Basin Configuration Model (Section 8) were mostly analysed in the same way as the EFlows sites: their monthly natural and current day flows were simulated, and their PES and FDEC agreed based on their locations within the HUs and/or proximity to one of the original 21 EFlow sites.

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6.1 NATURAL MONTHLY FLOWS FOR ALL 39 SITES

Natural monthly data for the 21 EFlow sites and 18 hydrological sites, for the period 1920 to 2012, were simulated by the hydrological team. These were needed to improve understanding of the hydrological nature of the sites through an analysis of dry-season flows (Section 6.4), to provide a starting point for the compilation of the EFlows tables (Section 7) and as the starting and reference points in the EFlows Basin Configuration Model (Section 8).

6.2 NATURAL DAILY FLOWS FOR THE 21 EFLOWS SITES

Natural daily flows were also simulated for the 21 EFlow sites, for the period 1948 to 2002, in order to ascertain the proportions of Mean Annual Runoff (MAR) that occur as low flows/ intra-annual floods and as larger floods. As part of this, the Hydrology module of the comprehensive EFlows method DRIFT was used to calculate the size of the 1:2, 1:5, 1:10 and 1:20 year (Section 7.2). As daily flows were not modelled for the 18 hydrological sites, their proportion of MAR contributed by inter-annual floods was estimated based on nearby EFlow sites, their location within the river, and the similarity of their monthly flow pattern and Hydrological Index.

6.3 RULES FOR DETERMINATION OF FDEC FOR ANY FLOW REGIME OF INTEREST

A crucial step in the overall process was allocating a Flow-driven Ecological Condition (FDEC) to any flow regime under consideration. The FDEC, on a scale from A to E, is an expression of the expected level of ecological condition that could be supported by a flow regime, all else being equal (i.e. with no other interventions causing a loss in ecological condition). The FDEC is an essential input into the EFlows Basin Configuration Model and provides a means of comparing the flow regime for each scenario/site with the natural situation. Estimation of its symbol uses two components of the flow regime:• Dry season: August to November• Wet season: January to April.

These seasons were defined based on consideration of the annual pattern of flows (Figure 7.2). The seasons were separated because flow changes can affect them differently: dry-season flows, for instance, can increase or decrease with basin development whereas wet-season flows usually decrease. Additionally, the EFlows tables (next section) are created through separate consideration of high and low flows in the wet season and so the months involved have to be specified. For any scenario, the sum of the monthly average flows for each season is expressed as a percentage of the sum of natural monthly flows for that season. Once known, these percentages have to be evaluated in terms of how much ecological change they are expected to drive. In most cases sites are likely to experience flows that are lower than natural due to abstractions and damming. Some sites, however, may experience flows that are higher than natural, particularly in the dry season,

6.HYDROLOGICAL

ANALYSES

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due to releases from upstream dams. Whether scenario flows are greater or less than natural, they represent changes from natural that could have equal effects on the FDEC categorisation of a site, even if the actual impact is different. A site could have higher than natural flows in one scenario, for instance, and lower than natural flows in the other, but a resulting FDEC categorisation of B in both cases although the actual ecological condition it would support would be quite different. To translate from percentages of seasonal flow changes to FDEC categories, the following rules were developed:• For those scenarios/sites with lower than natural flows, the rules for deciding on the FDEC category were gleaned from the EFlows tables (Section 7). • For those scenarios/sites with higher than natural flows there are no international guidelines on the link between specific higher flows and ecological condition. In these instances, rules were created, guided by the estimated PES of each site provided by the Basin Division Workshop delegates (Table 5.1). For example: a. Site 1.1 currently has dry season flows of about 175% of natural dry season flows. The PES was estimated during the workshop to be a B; b. Site 7.2 has dry season flows at 136% of natural, and the estimated PES was A/B; c. Site HS16 has dry season flows at about 530% of natural and the estimated PES was C/D.

In all three cases, alteration in the flow regime was considered by the delegates to be the key driver of ecological condition and so the proportional increase in flow relative to natural, and the current PES1, could be used as a guideline for developing the FDEC rules. Site 1.1, for example, was used to make the link that dry season flows between 150 and 200% of natural might produce an estimated B category FDEC.

From these considerations, a set of rules was developed (Table 6.1). The season with the greatest change from natural determines the resulting FDEC. Thus, for example:• The flow regime could have dry season flows that are 95% of natural and wet season flows that are 80% of natural. Considering that the greatest proportional change in flow occurs in the wet season and applying the rules below, a FDEC of A/B is returned (Rule 2);• If the dry season and wet season flows are both 70% of natural, then the FDEC would be B (Rule 3);• If the wet season flows are 90% of natural and the dry season flows are 290% of natural, then the FDEC would be C (Rule 5);• If the wet season flows are 30% of natural and the dry season flows are 100% of natural, then the FDEC would be D/E (Rule 8).• More generally: • If the dry season and wet season flows are between 95 and 102 % of natural then the FDEC would be A (Rule 1); • If the dry season and wet season flows are between 80 and 95 % and/ or between 102 and 150 % of natural respectively then the FDEC would be A/B (Rule 2); • If the dry season and wet season flows are between 69 and 80 % and/ or between 150 and 200 % of natural respectively then the FDEC would be B (Rule 3); • And so on (Table 6.1).

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The rules were applied to all 39 sites to determine their existing FDECs (see Section 8.1, Table 8.1). This sometimes resulted in a FDEC category that was lower than the PES category, which would not be the expected relationship because the overall ecological condition should not be higher than the ecological condition that is supported by the flow regime. This anomaly was accepted as part of the uncertainty within the whole process, however, due to the lack of detailed information and assumptions that had to be made. The mismatch may point to the need for either an adjustment to the estimated PES made by the workshop delegates or an adjustment to the rules, or both. None of these adjustments were possible in Phase 1 due to time and data constraints but will be addressed in Phase 2.

Table 6.1

Rules translating seasonal percentages of

natural flows to FDEC

6.4 ANALYSIS OF CURRENT DRY-SEASON FLOWS

Many assumptions had to be made when setting up the hydrological model for the Luangwa Basin because of the paucity of measured flow data, abstraction records and release records for the dams (explained in Report Number 4 in this series). The model provides a reasonable characterisation of flow regimes in the basin rather than accurate daily/monthly flows.

Although not directly needed for the EFlows Basin Configuration Model, an analysis of the flows produced by the hydrological model for the 21 EFlow sites provided some interesting insights into the nature of their flow regimes and how these are changing with time. In this analysis the focus was on the dry season, with monthly flows expressed as a percentage of natural flows for the dry months June to November, for a 20-year period between 1992 and 2012. This rapid assessment, based on monthly volumes, cannot detect impacts on flow that might result from daily fluctuations due to, for instance, peaking hydropower operation.

Ten of the 21 sites had a natural or near-natural (less than 5% deviation from natural) flow regime for each of the dry-season months, that is, they were Category A FDEC but not necessarily with an A Category PES:

• 1.2 – PES B • 6.1 – PES C• 2.1 – PES B/C • 7.1 – PES B• 2.2 – PES B/C • 8.1 – PES B• 3.1 – PES B • 8.2 – PES B• 5.1 – PES B • 11.1 – PES B.

Rule If seasonal flows are between FDEC

1 95 and 102 % of natural, then the FDEC is: A2 80 and 150 ” A/B3 69 and 200 ” B4 61 and 250 ” B/C5 53 and 300 ” C6 47 and 450 ” C/D7 35 and 800 ” D8 28 and 1000 ” D/E9 25 and 2000 ” E

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Their Category A FDEC, together with PESs ranging from Category B to C, indicate that site degradation was probably due to non-flow related impacts.

The remaining 11 sites showed varying degrees of change from natural, as follows.

Sites 4.1 and 4.2, on the Lundazi River on the eastern side of the basin, are downstream of a supply dam on this river near the town of Lundazi, with Site 4.1 closer to the dam and Site 4.2 further downstream. Until about 1997, almost all of the natural flow (100% in most dry season months) was retained at the dam, with Site 4.1 showing little or no flow from July to November (Figure 6.1). Some recovery was apparent by Site 4.2, where 50% of natural flow occurred during the same years and months. Site 4.1 was allocated a category C PES by the workshop delegates, with a category D FDEC. Site 4.2 was allocated a category C PES with a category B/C FDEC.

1 As mentioned in Section 6.3, a FDEC being lower than PES was sometimes unavoidably the case. In the case of site 4.1, the overall PES may have been skewed towards a better than expected condition by relatively good water quality and habitat integrity (each afforded a B PES) with less emphasis placed on flow conditions in the overall assessment of PES.

Figure 6.1

Current monthly dry-season flows as a percentage of natural

monthly flow at Sites 4.1 and 4.2 on the Lundazi

River

The pattern of flows changed from 1997 onwards, with more flow in the river in a widely scattered pattern. In most years, Site 4.1 showed quite high percentages of natural flow in the early dry season (60-80%) but with the percentages still reducing over the dry months (mostly to between 20-60%, but also often down to 0% toward the end of the dry season). Site 4.2 showed higher percentages of flow remaining than Site 4.1, presumably due to inflow from the catchment (80-90% in early dry season and 50-70% later in the season).

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Sites 1.1 and 7.2, on the Lusiwasi River on the western escarpment, are downstream of the Lusiwasi Hydropower Dam, with Site 1.1 closer to the dam and Site 7.2 further downstream.

Low flows are above natural at both sites through much of the dry season, particularly between June and September when they are up to 250% above natural at Site 1.1 and slightly lower at Site 7.2 (Figure 6.2). This is presumably due to the dam releasing stored water.

By the end of the dry season, in November, flows are reduced to about 75-80% of natural, presumably reflecting insufficient dam storage to maintain the early dry-season releases through the whole dry season. The pattern is consistent through the period analysed.

Site 1.1 was allocated a Category B PES with a Category B FDEC. Site 7.2 was allocated a Category A/B PES with a Category A/B FDEC.

Figure 6.2

Present-day monthly dry-season flows as a percentage of natural

monthly flows at Sites 1.1 and 7.2 on the Lusiwasi

River

Sites 12.1 and 12.2, on the upper Lunsemfwa River, are on the south-western escarpment at the upper edge of an important agricultural area. Site 12.1, furthest upstream, has near natural flows (Figure 6.3), never dropping below 80% of natural during the dry season, presumably due to low levels of abstraction.

Abstraction levels are far higher downstream, with Site 12.2 flows dropping to around zero at the end of the dry season in some years.

Site 12.1 was allocated a Category C/D PES with a Category A/B FDEC. Site 12.2 was allocated a Category C/D PES with a Category C/D FDEC.

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Figure 6.3

Present-day monthly dry-season flows as a percentage of natural monthly flows at Sites

12.1 and 12.2 on the upper Lunsemfwa River

Site 14.1, on the Mwonboshi River, is toward the south-west extreme of the basin and downstream of an irrigation dam (Figure 6.4). The river has a flashy hydrograph, indicative of an arid river.

Flows are naturally very low over the dry season, and presently drop to 50-70% of natural (Figure 6.5). October is often the month with the lowest percentage of natural flow.

Site 14.1 was allocated a Category C PES with a Category B/C FDEC.

Figure 6.4

The Lunsemfwa sub-basin, showing the main

river, the location of dams and the EFlow sites

23


Figure 6.5

Present-day monthly dry-season flows as a percentage of natural

monthly flows at Site 14.1 on the Mwonboshi River

Sites 15.1 and 15.2 on the Lunsemfwa River, are near the southern boundary of the basin. They are downstream of the Mita Hills Hydropower Dam, with Site 15.1 closest to the dam. The two sites exhibit very similar flow patterns, with flows substantially above natural throughout the dry season (Figure 6.6) because of releases from the dam to generate hydropower. Both Sites 15.1 and 15.2 were allocated a PES Category B/C with a Category D FDEC2.

Figure 6.6

Present-day monthly dry-season flows as a percentage of natural monthly flows at Sites

15.1 and 15.2 on the Lunsemfwa River,

downstream of the Mita Hills Dam

Site 9.1 is on the mainstem Luangwa upstream of its confluence with the Lunsemfwa River. It experiences both slight decreases and slight increases in flow (Figure 6.7). The increases, to about 105% of natural, are evident at the onset of the dry season, possibly reflecting the tail-end influence of releases from Lusiwasi Dam (Sites 1.1 and 7.2). Slight decreases below natural occur at the end of the dry season, perhaps due to decreasing releases from the dam together with abstraction from tributaries on the eastern escarpment.

24


Site 9.1 was allocated a Category B PES with a Category A FDEC. It has been described here rather than with the other A category sites simply to illustrate the possible extent of influence of the Lusiwasi Dam.

2 The FDEC was lower than the PES in this case because the overall PES was skewed towards better than expected ecological condition by non-flow related factors.

Figure 6.7

Present-day monthly dry-season flows as a percentage of natural monthly flows at Site

9.1 on the Luangwa River, upstream of its

confluence with the Lunsemfwa River

Site 10.1 is on the Luangwa mainstem at the outlet of the basin and just upstream of the confluence with the Zambezi River. All the abstractions and other manipulations for flow within the basin are summarized in the hydrological data for this site.

The end result is a slight to moderate increase above natural flow throughout the dry season (Figure 6.8) indicative of higher than normal flows arriving from the hydropower dams on the Lunsemfwa system.

Flows reach their highest above-natural values in October and November, suggesting dam releases are maintained at a constant volume during the months when flow would naturally be declining.

Site 10.1 was allocated a PES Category B/C with a Category A/B FDEC.

Figure 6.8

Present-day monthly dry-season flows as a percentage of natural monthly flows at Site 10.1 on the Luangwa

River, upstream of its confluence with the

Zambezi River

25


Using the understanding gained from analysis of the hydrological data, an EFlows table was compiled for each of the 21 EFlows sites and 18 hydrological sites; these indicate the monthly volume of flow that it is believed would support the range of ecological conditions from A (natural) to D (highly modified). The tables are a major input to the EFlows Basin Configuration Model. To compile them, five main steps were completed for each site:1. Calculate the Hydrological Index of the site;2. Separate the volumes of total flow residing in the floods and in the low flows;3. Calculate the flood volume for each FDEC level and allocate it to the months of the wet season;4. Calculate the low flow volume for each FDEC level and allocate it to all the months of the year;5. Combine flood and low-flow volumes per month in one table to produce a rapid EFlow recommendation for each FDEC category.

7.1 CALCULATE THE HYDROLOGICAL INDEX (HI) FOR EACH OF THE SITES

Flow regimes differ across landscapes and climates, from flashy, to seasonal or perennial, and with or without great monsoonal flood seasons. The Hydrological Index (HI) (Hughes and Munster, 1993) provides a first insight into the type of flow regime that occurs at any site of interest for which data on monthly volumes of flow are available.

The HI reflects the variability of flow and the strength of base flow, producing a low value for strongly perennial rivers and a high one for ephemeral rivers.

The HI values for all 39 sites were calculated (Table 7.1). The Lusiwasi at Site 1.1, the Lukusashi at Site 11.1 and the Luangwa mainstem have the lowest values, suggesting they are strongly perennial systems.

The Munyamadzi and Mwonboshi Rivers, two tributaries of the Lunsemfwa River, have the highest HI values, indicating seasonal rivers with flashy hydrographs, very low dry season flows and possibly no flow at times.

7. COMPILATION

OF THEEFLOWSTABLES

26


Site River Homogeneous Unit

Natural MAR

(MCM)

Current MAR

(MCM)Hydrological

Index (HI)

2.1 Luangwa 2 870 870 4.03.1 Luwumbu 3 41 41 6.7

HS1 Luangwa 8 3066 3066 3.9HS2 Luwumbu 8 509 509 6.2

8.1 Luangwa 8 3575 3575 4.1

HS4 Luangwa 8 5603 5603 4.294.1 Lundazi 4 81 74 7.84.2 Lundazi 4 175 168 7.6

HS3 Lundazi 8 306 299 7.51.2 Munyamadzi 1 245 245 13.17.1 Munyamadzi 7 606 606 13.0

HS5 Luangwa 8 6197 6189 4.3

HS6 Munyamadzi 8 678 606 10.0HS8 Luangwa 8 6951 6944 4.65.1 Lukusuzi 5 134 134 7.7

HS7 Lukusuzi 8 189 189 7.7HS10 Luangwa 8 8041 8033 4.7

6.1 Msandile 6 55 55 7.42.2 Msandile 2 227 227 7.0

HS9 Lutembwe 8 866 862 7.18.2 Luangwa 8 8907 8896 4.51.1 Lusiwasi 1 208 197 3.47.2 Lusiwasi 7 365 353 5.0

HS11 Luangwa 8 9217 9206 4.5HS17 Luangwa 8 10088 10065 4.4HS18 Mvuvye 8 232 232 7.3

9.1 Luangwa 9 10611 10587 4.4HS12 Luangwa 8 10877 10853 4.411.1 Lukusashi 11 870 870 4.1

HS13 Lunsemfwa 9 3095 3095 6.0HS14 Lukusashi 11 6656 6432 4.912.1 Lunsemfwa 12 411 408 6.212.2 Lunsemfwa 12 1082 1025 6.2

HS15 Mulungushi 15 765 702 9.514.1 Mwomboshi 14 223 219 23.2

HS16 Mulungushi 12 486 427 7.915.1 Lunsemfwa 15 2430 2270 7.215.2 Lunsemfwa 15 3348 3124 7.710.1 Luangwa 10 17642 17395 4.8

Table 7.1

Current and natural Mean Annual Runoff

(MAR), and the Hydrological Index (HI),

for the 39 sites (with sites arranged roughly in order

from the headwaters to the downstream end of

the basin)

27


7.2 SEPARATE NATURAL LOW- FLOW AND INTER-ANNUAL FLOOD VOLUMESAs basin development proceeds and dams store flood water it is becoming increasingly important to set EFlows for floods as well as for low flows. This requires an initial calculation of how much of the total flow volume resides in each of these flow components. This was undertaken for the 21 EFlows sites only, as the daily flow data were not available for the 18 hydrological sites at that time.

The proportions of natural MAR residing in inter-annual floods (i.e. ≥ 1:2 year floods) ranged from 11% to 62% and, in general, sites that are more perennial with lower HI values tended to have the lower proportions in floods (Table 7.2). Sites 1.1 and 11.1, for instance, are on perennial rivers with low HI values and have less than 15% of their flow as inter-annual floods. By contrast, the seasonal Mwomboshi River has a high HI value and 62% of its flow is as inter-annual floods.

For the hydrological sites, the proportion of total volume contained in the inter-annual floods was estimated from the 21 EFlows sites based on proximity, HI values and shape of the annual hydrograph.

Site River% nMAR as

inter-annual flood flows

Total volume in inter-annual floods (MCM)

Hydrological Index (HI)

2.1 Luangwa 14.3 125 4.03.1 Luwumbu 25.5 10 6.78.1 Luangwa 16 574 4.14.1 Lundazi 58.7 48 7.8

4.2 Lundazi 58.7 102 7.6

1.2 Munyamadzi 42.2 103 13.17.1 Munyamadzi 42.2 256 13.05.1 Lukusuzi 59 79 7.76.1 Msandile 38.9 21 7.42.2 Msandile 38.9 88 7.08.2 Luangwa 25.7 2291 4.5

1.1 Lusiwasi 14.7 31 3.4

7.2 Lusiwasi 26.7 98 5.09.1 Luangwa 24.4 2588 4.411.1 Lukusashi 10.9 95 4.112.1 Lunsemfwa 12.6 52 6.212.2 Lunsemfwa 13 141 6.214.1 Mwomboshi 62.4 149 23.215.1 Lunsemfwa 16.3 395 7.215.2 Lunsemfwa 27.3 913 7.710.1 Luangwa 12.6 2221 4.8

Table 7.2

HI value, percentage and volume of the natural

MAR occurring as inter-annual floods at each

EFlows site

MCM = millions of cubic metres; nMAR = natural Mean Annual Runoff

28


The percentages in Table 7.2 (column 3) were used to calculate the total volume of water encompassed in the natural flood season at each EFlows site (shown in column 4 of that table). That volume was allocated to the months of the wet season as follows. The natural proportion of flow occurring in each month of the flood hydrograph was calculated (Step 2 in Table 7.3) and the proportions were then changed to volumes (Figure 7.1; and Step 3 in Table 7.3). The remaining natural flow volume per month was allocated to the low flow regime (step 4).

EFlow Process

Step Description Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep

Separationof naturalflows

1Monthly natural volume (MCM)

2.2 1.8- 4.6 17.4 74.2 77.1 24.6 8.3 5.7 4.5 3.6 2.8

2

Percentage of inter-annual flood volume

in each month (%)

2 8 35 36 12 4 3

3Natural

inter-annual flood volume

(MCM) 1.9 7.3 30.9 32.1 10.3 3.4 2.4

4

Natural low flow and

intra-annual flood volume

(MCM)

2.2 1.8 2.7 10.2 43.3 45.0 14.4 4.8 3.3 4.5 3.6 2.8

Table 7.3

The allocation of water volumes to dry (brown)

and wet (blue) season months, using Site 2.2 as

an example

Figure 7.1

Separation of low flows and intra-annual floods

from inter-annual floods for Site 2.2

7.3 CALCULATE INTER-ANNUAL FLOODS FOR ALL CONDITION CATEGORIESA decision then had to be made as to how much of the natural inter-annual flood volume should remain for each FDEC category.

There is little guidance in the literature on what proportion of the flood season volume should be maintained for each ecological category. Assuming that the larger floods will start to reduce as basin development expands but will not be substantially less during the early stages, inter-annual flood volumes were adopted for each FDEC category as specified in Table 7.4.

29


FDEC % of natural inter-annual flood volume remaining

A/B 99B 95

B/C 90C 80

C/D 70

D 60

Table 7.4

The percent of natural inter-annual flows

apportioned to each FDEC

This resulted in a specific inter-annual flood volume for each site and FDEC (Table 7.5).

These inter-annual flood volumes were allocated monthly through the flood season as per steps 5 and 6 in Table 7.6. At this point, then, the amount of water naturally residing in floods had been reduced per FDEC category and the reduced volumes apportioned to the wet-season months.

Table 7.5

Inter-annual flood volumes allocated to

each EFlows site for each FDEC category

EFlowsSite River

% nMAR

as inter-

annual flood flows

Total volume

in inter-

annual floods (MCM)

Volume allocated per FDEC (MCM)

A/B B B/C C C/D D

2.1 Luangwa 14.3 125 124 119 112 100 87 75

3.1 Luwumbu 25.5 10 10 9.9 9.4 8.3 7.3 6.3

8.1 Luangwa 16.0 574 568 545 517 459 402 345

4.1 Lundazi 58.7 48 47 45 43 38 33 29

4.2 Lundazi 58.7 102 102 98 93 82 72 62

1.2 Munyamadzi 42.2 103 102 98 93 83 72 62

7.1 Munyamadzi 42.2 256 253 243 230 205 179 153

5.1 Lukusuzi 59.0 79 78 75 71 63 55 47

6.1 Msandile 38.9 21 21 20 19 17 15 13

2.2 Msandile 38.9 88 87 84 79 71 62 53

8.2 Luangwa 25.7 2291 2268 2177 2062 1833 1604 1375

1.1 Lusiwasi 14.7 31 30 29 27 24 21 18

7.2 Lusiwasi 26.7 98 97 93 88 78 68 59

9.1 Luangwa 24.4 2588 2562 2459 2329 2070 1812 1553

11.1 Lukusashi 10.9 95 94 90 85 76 66 57

12.1 Lunsemfwa 12.6 52 51 49 47 41 36 31

12.2 Lunsemfwa 13.0 141 140 134 127 113 99 85

14.1 Mwomboshi 62.4 149 138 132 125 112 98 84

15.1 Lunsemfwa 16.3 395 391 375 355 316 276 237

15.2 Lunsemfwa 27.3 913 904 868 822 731 640 548

10.1 Luangwa 12.6 2221 2199 2110 1999 1777 1555 1333

30


EFlow Process




2.2 1.8 4.6 17.4 74.2 77.1 24.6 8.3 5.7 4.5 3.6 2.8

2

Percentage of inter-annual flood volume

in each month (%)

2 8 35 36 12 4 3

3Natural

inter-annual flood volume

(MCM) 1.9 7.3 30.9 32.1 10.3 3.4 2.4

4

Natural low flow and

intra-annual flood volume (MCM) (step

1-3)

2.2 1.8 2.7 10.2 43.3 45.0 14.4 4.8 3.3 4.5 3.6 2.8

Calculation of floods

5

Inter-annual flood % of natural (step 3) for a category A/B FDEC

99 99 99 99 99 99 99

6

Inter-annual flood volume for a category A/B FDEC (MCM)

1.9 7.2 30.6 31.8 10.1 3.4 2.4

Table 7.6

Table 7.6 repeated, with inter-annual flood

volumes allocated in steps 5 and 6, using Site 2.2 and a Category A/B

FDEC as an example

7.4 CALCULATE LOW FLOWS AND INTRA-ANNUAL FLOODS FOR ALL FDEC CATEGORIESWhile the inter-annual flood flows were calculated only for the wet-season months, the volume of water in low flows and intra-annual floods was calculated for every month (Figure 7.1). Entry into this calculation was via the South African Desktop Model (Hughes and Munster, 1999; Hughes and Hannart, 2003). This model uses results from past EFlows Assessments in South Africa to generalise on the proportion of natural flow required to support a river under different ecological conditions ranging from A (pristine) to D (largely modified).

The Desktop Model could not be used directly to provide EFlow estimates for the Luangwa Basin for the following reasons.• It only considers low flows and intra-annual floods, and so cannot provide a complete table of estimated EFlows because the requirement for larger floods is not considered.• It provides different values for rivers with different HI values, on the assumption that a smaller proportion of the overall flow of the river is needed to support a specific condition level in an arid river than a comparable condition level in a perennial river. This assumption is increasingly being challenged and is not adopted for the Luangwa Basin.• It often provides a gradually decreasing percentage of monthly flows with progression through the dry season. Considering that ecosystems become more stressed towards the end of the dry season when the quantity of water is at its lowest, many feel the percentage should be increasing rather than decreasing. In other words, although actual flows may decrease over the course of the dry season, as a percentage of natural, they should be increasing.• It was designed for South Africa, and provides predefined regions based on monthly flow distributions. The hydrographs for the Luangwa Basin do not match well with those for any of the South African regions, indicating that its flow regime is different in important ways. (e.g. the wet season starts later in the Luangwa Basin and is closer to a monsoonal type).

31


• When a ‘best fit’ South African region was chosen as a surrogate based on the monthly distribution of flows and the HI value (this was the Lowveld, Region 18), it produced unrealistic recommended EFlows. In order to maintain an A/B condition, for instance, the percentages recommended were above 100% of natural mean monthly flows for some months at some Luangwa sites, and as low as 20% for other months. Figure 7.2 provides, as an example, the Desktop Model result for Site 2.2 in the Luangwa Basin.• It only considers the relationship between reduced flows and ecological category, not increased flows.

Clearly the Desktop Model outputs could not be used per se. Instead, the Luangwa flow data were run through the Desktop Model to provide the pattern of recommended monthly EFlows. Using this, adjustments were made to the Desktop tables using the following guidelines.• Although the flow volumes declined toward the end of the dry season, the relative proportion was maintained or increased through the season. The driest month received the highest percentage of natural flows.• The month with the lowest proportion of low flows was kept as such. This was mostly represented by January, a wet season month in the Luangwa Basin, when the greater proportion of its flow is represented as flood flows.• The remaining months were adjusted to align with these criteria.

Figure 7.2

EFlows low-flow and intra-annual flood

requirements for Luangwa Site 2.2,

derived from the Desktop Model, as a percentage of

monthly natural low flows for each river condition

from A/B to D

This adjustment for Site 2.2, for instance, dropped the dry-season requirement (August to November) below 100% while retaining it at a higher percentage than the wet-season requirement (Table 7.7; Figure 7.3). The percentages are higher in the dry season when the total flow volumes consist of low flows and intra-annual floods only, unlike the wet season when inter-annual floods contribute a large proportion of the total flow.

Site 2.2 FDEC Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep

Desktop output AB 104 105 73 23 34 30 34 49 65 78 90 100

Adjusted Desktop output AB 97 97 73 70 67 67 64 69 75 93 96 96

Table 7.7

Monthly percentages from the Desktop Model output and the adjusted

output, to achieve an A/B FDEC at Site 2.2

32


Figure 7.3

EFlows low-flow and intra-annual flood

requirements adjusted for Luangwa Site 2.2, as a percentage of monthly

natural low and intra-annual flood flows for

each river condition from A/B to D.

The percentages were converted to a low flow and intra-annual flood volume for each month, condition and site, as per steps 7 and 8 in Table 7.8.

EFlow Process




2.2 1.8 4.6 17.4 74.2 77.1 24.6 8.3 5.7 4.5 3.6 2.8

2

Percentage of inter-annual flood volume in each month (%)

2 8 35 36 12 4 3

3Natural inter-annual flood volume (MCM)

1.9 7.3 30.9 32.1 10.3 3.4 2.4

4

Natural low flow and intra-annual flood volume (MCM) (step 1-3)

2.2 1.8 2.7 10.2 43.3 45.0 14.4 4.8 3.3 4.5 3.6 2.8


5


99 99 99 99 99 99 99

6


1.9 7.2 30.6 31.8 10.1 3.4 2.4

Calculation of low and intra-annual flood flows

7

Low flow and intra-annual flood % of natural for a category A/B FDEC

97 97 73 70 67 67 64 69 75 93 96 96

8

Low flow and intra-annual flood volume for a category A/B FDEC (MCM)

2.2 1.7 2.0 7.1 29.0 30.1 9.2 3.3 2.5 4.2 3.5 2.7

Table 7.8

The allocation of water volumes for monthly

low flows (steps 7 and 8), using Site 2.2 as an

example

The same process was followed for all 39 sites, with the outcomes in terms of recommended monthly low and intra-annual flood flows shown in Table 7.9. Please note that inter-annual flood volumes, as per 7.3, still need to be added (next section).

33


FDECPercentage of natural low and intra-annual flood flows suggested to support specific FDECs (inter-annual flood flows still to be added - see Section 7.5)

Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep

A/B 94-98 90-98 67-88 24-78 50-80 45-79 48-78 43-80 59-88 71-93 82-96 93-96

B 80-89 77-87 57-75 20-68 43-69 38-68 41-68 37-68 50-75 60-79 70-82 79-86

B/C 68-75 65-74 49-64 17-57 36-59 33-58 35-57 31-58 42-64 51-68 59-70 67-74

C 58-64 55-63 43-55 15-50 31-51 28-50 29-50 26-51 36-57 43-60 50-62 57-62

C/D 46-56 44-55 37-50 12-44 26-45 23-44 25-44 22-45 31-50 37-53 43-54 46-54

D 32-49 31-49 26-45 11-39 19-40 17-39 19-39 19-41 26-44 30-46 32-48 32-48

Table 7.9Summary of the estimated

EFlows recommendation for the low and intra-

annual flood component of the flow regime for

all Luangwa sites, as a percentage of monthly

natural flow, to support specified FDECs

7.5 SUMMARISE OVERALL EFLOWS REQUIREMENT FOR EACH EFLOWS SITEThe total EFlows requirement for each condition category for each of the 39 sites was then generated by adding the low and intra-annual flood flows and the inter-annual flood volumes for each month and converting these values to percentages of natural mean annual flow (Table 7.10: steps 9 and 10).

EFlow Process




2.2 1.8 4.6 17.4 74.2 77.1 24.6 8.3 5.7 4.5 3.6 2.8

2

Percentage of inter-annual flood volume in each month (%)

2 8 35 36 12 4 3

3Natural inter-annual flood volume (MCM)

1.9 7.3 30.9 32.1 10.3 3.4 2.4

4

Natural low flow and intra-annual flood volume (MCM) (step 1-3)

2.2 1.8 2.7 10.2 43.3 45.0 14.4 4.8 3.3 4.5 3.6 2.8


5


99 99 99 99 99 99 99

6


1.9 7.2 30.6 31.8 10.1 3.4 2.4

Calculation of low and intra-annual flood flows

7

Low flow and intra-annual flood % of natural for a category A/B FDEC

97 97 73 70 67 67 64 69 75 93 96 96

8

Low flow and intra-annual flood volume for a category A/B FDEC (MCM)

2.2 1.7 2.0 7.1 29.0 30.1 9.2 3.3 2.5 4.2 3.5 2.7

Overall EFlowrequirement

9Total volume for a category A/B (MCM)

2.2 1.7 3.9 14.3 59.6 61.9 19.3 6.7 4.9 4.2 3.5 2.7

10Overall EFlow % of natural for an A/B category

97 97 84 82.1 80.3 80.3 79 81 85 93 96 96

Table 7.10

The total EFlows requirement for an A/B FDEC (steps 9 and 10),

using Site 2.2 as an example

To conclude, the volume of flow that is the total EFlows requirement (step 9 in Table 7.10), was summed for each site and condition, and expressed as a percent of the total natural MAR (Table 7.11). The full EFlows tables detailing monthly volumes for each site are given in Appendix A.

34


Site Names River Names

Natural MAR

(MCM)

Total recommended EFlow (% of natural MAR) for specified FDECs

A/B B B/C C C/D D

2.1 Luangwa 870 80 70 61 54 47 42

3.1 Luwumbu 41 80 71 63 56 49 43

8.1 Luangwa 3575 81 70 62 55 48 42

4.1 Lundazi 81 81 75 69 61 53 45

4.2 Lundazi 175 81 75 69 61 53 45

1.2 Munyamadzi 245 81 74 67 58 50 43

7.1 Munyamadzi 606 81 74 67 58 50 43

5.1 Lukusuzi 134 81 75 69 61 53 45

6.1 Msandile 55 80 72 65 58 51 44

2.2 Msandile 227 81 73 66 59 52 45

8.2 Luangwa 8907 83 73 65 57 50 44

1.1 Lusiwasi 208 82 64 56 50 44 38

7.2 Lusiwasi 365 82 73 64 56 48 41

9.1 Luangwa 10611 82 73 64 57 50 44

11.1 Lukusashi 870 81 70 61 54 48 42

12.1 Lunsemfwa 411 81 70 61 54 47 41

12.2 Lunsemfwa 1082 81 70 61 54 47 42

14.1 Mwomboshi 223 82 76 71 62 54 44

15.1 Lunsemfwa 2430 81 71 62 55 48 42

15.2 Lunsemfwa 3348 83 73 65 58 51 44

10.1 Luangwa 17642 79 69 60 53 47 41

Range 79-83 64-76 56-71 50-62 44-54 38-45

Table 7.11

The total annual EFlows (including low flows,

intra-annual and inter-annual floods) recommended, as a

percent of natural mean annual flow, for all sites

and FDECs

These values were compared with international recommendations.

The Kafue Rapid EFlows Report (King and Brown 2014) summarises emerging norms from various parts of the world as to what the total EFlows should be, and this is repeated here. These regions do not necessarily use the ecological classification A to D as is used in southern Africa, and so the relevant condition levels are estimated from their descriptions.

• Europe and the U.K. The Water Framework Directive (WFD) of 2000 requires EU countries to achieve at least ‘good ecological status’ in most surface and ground waters by 2015. This presumably means a B or B/C condition. To achieve this, the UK has recommended that flow on any one day for most types of rivers should be at least 75% of natural, with higher values in the dry season.• U.S.A. The Nature Conservancy (TNC) concluded that 90% of flow is needed on any one day to sustain a (presumably) A or A/B river; 80-90% for a (presumably) B river; and that less than 80% will lead to moderate (C?) to major (D?) changes in the river.• Australia has suggested that 80-85% of flow would be needed to sustain a river at (presumably) B condition, 50% for (presumably) C condition and 30% for D condition.

Overall, for the studies described above and if one accepts the same proportions for recommended annual flow as for daily flow, about 90% of the natural MAR would be needed for an A/B condition; 75-90% for a B condition; 50-75% of flow for a C condition and 30-50% for a D condition.

The percentages of natural MAR calculated for A/B to D category conditions in the Luangwa Basin (Table 7.11) compare reasonably well with these

35


figures, considering that the ecological conditions being referred to in the international literature had to be assumed.

7.6 CALCULATE EFLOWS FOR SITES WITH HIGHER THAN NATURAL DRY-SEASON FLOWS Whereas most EFlow studies focus on the lower limits of flow that would maintain various ecological conditions, some have to address increases in flows above natural, mainly due to dam releases.

In the Luangwa Basin, Sites 15.1 and 15.2 (Figure 6.6) are downstream of the Mita Hills Dam on the Lunsemfwa River and the Mulungushi Dam on the Mulungushi River, both of which release greater than natural flows in the dry season to meet hydropower requirements. Sites 1.1 and 7.2 on the Lusiwasi River (Figure 6.2) experience both increases and decreases in natural flow in various months, depending on the hydropower releases from the upstream Lusiwasi Dam.

Due to these various combinations of releases, Sites 9.1 and 10.1 on the mainstem Luangwa (Figure 6.7 and Figure 6.8) also experience both increases and decreases in flows at different times of the year. Table 6.1 provides the rules for estimating FDEC in these situations.

7.7 IMPORT EFLOWS TABLES INTO CONFIGURATION MODELThe monthly percentages associated with each FDEC at each site (Appendix A) were translated into monthly volumes and imported into the EFlows Basin Configuration Model.

Where slight inconsistencies arose (e.g. if the percentage contributions of two upstream sites to a downstream site were markedly different from the natural contributions when both were accorded the same (lower than natural) FDEC), adjustments were made to the EFlows table accordingly, and the results re-imported.

Outputs of the model from the scenario analysis are reported in Section 9.

36


8.1 INTRODUCTIONThe EFlows Basin Configuration Model is an Excel-based tool designed for a first, low-resolution assessment of the implications of water resource developments on a basin’s river ecosystem. It can be used to illustrate how development in one part of the basin could impact the river system, and thus water resources, in other parts.

Developments such as an irrigation area or dam can be inserted in a location of interest in the basin, and an estimate made of their impact on the flow regime and ecological condition of the nearest downstream site and others further downstream likely to be affected.

The tool helps develop an understanding of where in the basin future water

resources could be located and where they should perhaps be avoided if they would conflict with other aspirations for the basin.

It should not be used for detailed project planning (location, design, operation) of a new water resource development. In order to run the EFlows Basin Configuration Model, the 21 EFlows sites needed to be linked through the drainage network. This required the addition of 18 hydrological sites at key points in the network, resulting in a total of 39 sites for the analysis (Table 8.1; Figure 8.1).

Information requirements for each site were the incremental3 and cumulative4 natural and current day flows, and the EFlows for each FDEC from the EFlow tables (Appendix A).

8. THE EFLOWSBASIN

CONFIGURATION MODEL

37


Site Names River Existing

PESExisting

FDEC x-coordinate y-coordinate

2.1 Luangwa B/C A 33.0265 -10.2513.1 Luwumbu B A 33.436 -10.767

HS1 Luangwa B A 32.8937 -11.109HS2 Luwumbu B A 32.901 -11.1118.1 Luangwa B A 32.8766 -11.184

HS4 Luangwa B A 32.3418 -12.0634.1 Lundazi C D 33.1626 -12.2714.2 Lundazi C B 32.7266 -12.181

HS3 Lundazi B A/B 32.342 -12.0791.2 Munyamadzi B A 31.7152 -12.0747.1 Munyamadzi A/B A 31.8016 -12.284

HS5 Luangwa B A 32.1465 -12.443HS6 Munyamadzi B A 32.1403 -12.448HS8 Luangwa B A 32.1231 -12.5865.1 Lukusuzi B A 32.5111 -12.734

HS7 Lukusuzi B A 32.1256 -12.6HS10 Luangwa B A 31.8398 -13.07

6.1 Msandile C A 32.4624 -13.3922.2 Msandile B/C A 32.0769 -13.289

HS9 Lutembwe B A 31.8367 -13.0858.2 Luangwa B A 31.8087 -13.0841.1 Lusiwasi B B 31.0243 -13.1867.2 Lusiwasi A/B A/B 31.2849 -13.429

HS11 Luangwa B A 31.3131 -13.514HS17 Luangwa B A 30.8039 -14.032HS18 Mvuvye B A 30.7938 -14.061

9.1 Luangwa B A 30.4632 -14.438HS12 Luangwa B A 30.2192 -14.91411.1 Lukusashi B A 30.6731 -13.606

HS13 Lunsemfwa B A 30.1997 -14.901HS14 Lukusashi B C 29.9924 -14.61112.1 Lunsemfwa C/D A/B 29.2353 -13.65512.2 Lunsemfwa C/D D 29.1324 -13.935

HS15 Mulungushi B/C D 29.1701 -14.89114.1 Mwomboshi C B/C 28.8421 -14.793

HS16 Mulungushi C/D D 28.8598 -14.77815.1 Lunsemfwa B/C D 29.1848 -14.86615.2 Lunsemfwa B/C D 29.6679 -14.74810.1 Luangwa B/C A/B 30.2111 -14.995

Table 8.1

Coordinates, PES and FDEC for the 39 sites

3 Incremental flow: the flow within a sub-basin provided by tributaries and overland flow, which is added to the cumulative flow arriving from the upstream sub-basins.4 Cumulative flow: the total flow at a point in a river.

38


Figure 8.1

The 21 EFlows sites (e.g. 15.2) and 18 hydrological

sites (e.g. HS14) for the Luangwa Basin

To illustrate the need for and purpose of the 18 hydrological sites, an example is provided in Figure 8.2. Hydrological site HS6 on the Munyamadzi River (with Site 7.1 further upstream, and Site 2.1 above that) is needed together with the flows on the mainstem Luangwa immediately upstream of the Munyamadzi confluence (HS5), in order to ascertain the contribution of the Munyamadzi tributary to the mainstem, and allow for the assessment of the effects on the mainstem of altered flows on the Munyamadzi.

Figure 8.2

Example of the location of and need for

hydrological sites to link EFlow Sites through the

drainage network so that the EFlows Basin

Configuration Model can run

39


Site Contributing Sites RiverCurrent

PESCurrent

FDEC

2.1 Luangwa B/C A3.1 Luwumbu B A

HS1 2.1 Luangwa B AHS2 3.1 Luwumbu B A8.1 HS1 HS2 Luangwa B A

HS4 8.1 Luangwa B A4.1 Lundazi C D4.2 4.1 Lundazi C B

HS3 4.2 Lundazi B A/B1.2 Munyamadzi B A7.1 1.2 Munyamadzi A/B A

HS5 HS3 HS4 Luangwa B AHS6 7.1 Munyamadzi B AHS8 HS5 HS6 Luangwa B A5.1 Lukusuzi B A

HS7 5.1 Lukusuzi B AHS10 HS7 HS8 Luangwa B A

6.1 Msandile C A2.2 6.1 Msandile B/C A

HS9 2.2 Lutembwe B A8.2 HS9 HS10 Luangwa B A1.1 Lusiwasi B B7.2 1.1 Lusiwasi A/B A/B

HS11 8.2 Luangwa B AHS17 HS11 7.2 Luangwa B AHS18 Mvuvye B A

9.1 HS17 HS18 Luangwa B AHS12 9.1 Luangwa B A11.1 Lukusashi B A

HS14 11.1 Lunsemfwa B AHS13 HS14 15.2 Lukusashi B B/C12.1 Lunsemfwa C/D A/B12.2 12.1 Lunsemfwa C/D C

HS15 14.1 HS16 Mulungushi B/C D14.1 Mwomboshi C B/C

HS16 Mulugushi C/D D15.1 12.2 Lunsemfwa B/C C/D15.2 15.1 HS15 Lunsemfwa B/C D10.1 HS13 HS12 Luangwa B/C A/B

Table 8.2

Pre-scenario layout of the EFlows Basin

Configuration Model sites

40


Linked to each site within the model are its annual and monthly flows for natural and current day. Natural flow data are used as the baseline, with current day flow data presented as percentages of natural. Further on, scenario flows are also presented as percentages of natural.

In the model, the flows for any one site are added to the flows arriving from upstream linked sites, to determine total flow at each downstream point. An example is provided in Table 8.3 for Sites 4.1, 4.2 and HS3.• Site 4.1 flows to Site 4.2, which then flows to Site HS3 (columns B and C, rows 1, 2, and 3).• The current FDECs of these sites are D, B and A/B, respectively (column D, rows 1, 2, and 3).• The current annual incremental flow contributions are 73.7, 94.2 and 130.9 MCM, respectively (column E, rows 1, 2, and 3).• The current cumulative flow at HS3 is 298.8 MCM (column F, row 3).

A

Row

B

Site

CContributing

Sites

D

FDEC

E

Current incremental flow (MCM)

F

Current cumulative flow (MCM)

1 4.1 D 73.7 73.72 4.2 4.1 B 94.2 167.93 HS3 4.2 A/B 130.9 298.8

Table 8.3

Example of the accumulation of flows in the Basin Configuration

Model for Sites 4.1, 4.2 and HS3

In preparation for scenario analysis, each site is linked to its contributing sites. The current PES and FDEC of all sites are entered, as are the current volume of flow per dry and wet season (expressed as percent of natural (Figure 8.3).

Figure 8.3

Section of the EFlows Basin Configuration Model

showing the flow and sources of information.

Step 1: Initial set up

41


8.2 ASSESSMENT OF SCENARIOS AND THE ACHIEVEMENT OF TARGETSScenario analysis starts by choosing potential future FDECs that will be used as targets in the model.

The target FDECs may be set, for example, to:• Meet conservation purposes or international obligations (e.g. Scenario 2: Section 9.2);• Reflect estimated reduced flows linked to a proposed development (e.g. Scenario 3: Section 9.3);• Reflect the flow consequences of an array of small dams (e.g. Scenario 4: Section 9.4);• Reflect estimated increased flows linked to a proposed hydropower development (e.g. Scenario 5: Section 9.5);• Reflect altered flows due to a combination of management objectives (e.g. Scenario 6: Section 9.6).

For any scenario selected for investigation, a new FDEC category is inserted for the sites targeted (Section 9 provides details of how these FDEC categories were chosen for the scenarios analysed in this document). In the hypothetical example given in Figure 8.4, for instance, a new target FDEC of D was selected for Site 4.2, which was chosen to reflect what was felt to be the likely impact of some planned upstream small dams on its existing FDEC of C. The model accesses the monthly flows for a FDEC category D for Site 4.2. These flows are derived from the percentages of natural in the EFlows table for Site 4.2 (Appendix A). The volumes are routed downstream through all relevant sites, and are used to calculate adjusted percentages of natural dry and wet season flows in each case.

Figure 8.4


showing the flow and sources of information

for a scenario. Step 2: Specify scenario target

FDECs at relevant sites; fetch relevant EFlows

information; determine seasonal percentages

at each site and the consequent downstream

changes in percentages

Using the rules in Table 6.1, the seasonal proportions are then converted back to a new scenario FDEC for each impacted site (Figure 8.5). The current and scenario FDEC categories can then be compared.

42


Figure 8.5


showing the flow and sources of information.

Step 3: Determine the resulting FDEC by

applying the rules in Table 6.1

In this hypothetical example, the key results with a target condition of D at site 4.2 are as follows:

(1) The percentages gleaned from the EFlows table reduce the existing seasonal percentages of natural flow at Site 4.2, particularly in the dry season. The wet season percentage flow is reduced from 97.8 % to 68.3 % of natural, and the dry season percentage flow is reduced from 70.1 % to 38.3 % of natural). The FDEC rules in Table 6.1 indicate that the new flows at Site 4.2 would drop it from a B category FDEC to a D category FDEC, as per the target.(2) As a result of the flow changes at Site 4.2, the downstream site, HS3, also experiences reduced seasonal flows. There is a reduction from 98.7% to 81.9% and from 82.9 % to 64.7% during the wet and dry seasons respectively. This causes its FDEC to drop from A/B to B/C.(3) There are negligible impacts felt at the most downstream site in the basin (Site 10.1) because flow contributions from other parts of the basin reduce the impact.

Once the new FDEC has been predicted for each affected site, an estimate can be made of the ecological conditions it would support. This is explained in the next section.

8.3 TRANSLATION OF FDEC BACK TO OVERALL ECOLOGICAL CONDITION (EC)The new FDEC category for any one site can be translated back to an overall ecological category (EC) based on an understanding of the relationship between the existing overall ecological condition defined by the PES category and existing FDEC.

First, the existing PES and FDEC (Table 8.1) are converted to scores using the ecoclassification5 process of Kleynhans et al. (2008) (Table 8.4). The middle value of the percentage range is taken for each category so that, for instance, an existing B category is scored as 85 %, and a C as 70 %.

43


Overall Ecological category

(PES)

Description of the habitat% of

natural total score

A Unmodified. Still in a natural condition. >95A/B >90.5

BNear natural. A small change in natural habitats and biota has taken place but the ecosystem functions are essentially unchanged.

>85

B/C >80.5

C

Moderately modified. Loss and change of natural habitat and biota has occurred, but the basic ecosystem functions are still predominantly unchanged.

>70

C/D >60.5

D Largely modified. A large loss of natural habitat, biota and basic ecosystem functions has occurred. >50

D/E >40.5

E Seriously modified. The loss of natural habitat, biota and basic ecosystem functions is extensive. >30

E/F >20.5

F

Critically modified. An almost complete loss of natural habitat and biota. In the worst instances, basic ecosystem functions have been destroyed and the changes are irreversible.

>0

Table 8.4

Relationship between scores in the

ecoclassification process and ecological categories (adapted from Kleynhans

et al. 2008)

In a scenario, the numerical difference between the scores for existing PES and existing FDEC is first ascertained. For instance, at Site 4.2, the existing PES is C (score=70) and the existing FDEC is B (score=85), indicating that at least some of the ecological degradation is probably from causes other than flow manipulation.

The difference between the scores is -15. This difference is used to adjust the scenario FDEC score (category D, score = 50) to a scenario EC score (resulting EC score = 50-15 = 35; therefore resulting overall EC is E) (Figure 8.6).

This flow change is felt further downstream, where site HS3 drops from an overall EC of B to C.In the scenario analysis in Section 9, the results are presented in tables,

5 The scores in the ecoclassification process are relative to natural, for each metric and overall.

44


Figure 8.6

Relationship between scores in the

ecoclassification process and ecological categories (adapted from Kleynhans

et al. 2008)

showing the current FDEC, seasonal percentages, the target FDEC for all sites, and the resulting FDECs and seasonal percentages. In Section 9.7, the results are summarized spatially and the FDECs and estimated resulting overall ECs provided for all sites.

45


With the model configured, scenarios were selected that could illustrate different possible permutations of basin development:• Baseline; • Suggested non-negotiables;• Eastern Province water supply dams;• Muchinga Province small dams;• Hydropower in western basin;• All of the above.

Scenarios were entered into the configuration model by specifying a target FDEC for each site (Section 8.3). Where a new target FDEC is not indicated for a site, then it is the same as the current FDEC.

9.1 SCENARIO 1: BASELINE – THE EXISTING SITUATIONThis summarizes the existing flows at each site based on the Phase 1 hydrological simulations (Report Number 4 in this series) (Table 9.1 and Figure 9.1), together with the existing FDEC derived using Table 6.1.

9. SCENARIO SELECTION

AND ANALYSIS

SiteCurrent Configuration

Current FDECWet (Jan-Apr) as

% NatDry (Aug-Nov) as

% Nat

2.1 A 100.0 100.03.1 A 100.0 100.0

HS1 A 100.0 100.0HS2 A 100.0 100.08.1 A 100.0 100.0

HS4 A 100.0 100.04.1 D 95.3 35.54.2 B 97.8 70.1

HS3 A/B 98.7 82.91.2 A 100.0 100.07.1 A 100.0 100.0

HS5 A 100.0 99.0HS6 A 100.0 100.0HS8 A 100.0 99.15.1 A 100.0 100.0

HS7 A 100.0 100.0HS10 A 100.0 99.2

6.1 A 100.0 100.02.2 A 100.0 100.0

HS9 A 99.6 97.18.2 A 99.9 99.01.1 B 84.4 174.77.2 A/B 91.1 136.1

Table 9.1

Scenario 1: current FDEC and seasonal flows as

percentages of natural MAR

46


Figure 9.1

Scenario 1: map of current FDEC for each of the

EFlow sites

SiteCurrent Configuration

Current FDECWet (Jan-Apr) as

% NatDry (Aug-Nov) as

% Nat

HS11 A 99.9 99.0HS17 A 99.6 100.5HS18 A 100.0 100.0

9.1 A 99.6 100.4HS12 A 99.6 100.411.1 A 100.0 100.0

HS14 A 100.0 100.0HS13 C 91.1 261.512.1 A/B 99.6 91.812.2 D 97.8 40.1

HS15 D 74.5 511.214.1 B/C 98.1 62.9

HS16 D 60.7 529.915.1 D 84.2 451.515.2 D 82.5 466.710.1 A/B 95.7 145.0

47


9.2 SCENARIO 2: SUGGESTED NON-NEGOTIABLESIn the Basin Division workshop, it was agreed to explore an initial scenario of ‘non-negotiables’ that would encompass the following:

• Maintain the Lunsemfwa headwaters (Site 12.1) and the Nyika Plateau headwaters (Site 2.1 and Site 3.1) in a Category A or A/B ecological condition;• Maintain the mainstem Luangwa River entering (Site 8.1) and leaving (Site 8.2) South Luangwa National Park and North Luangwa National Park in at least a Category B ecological condition;• Maintain the lower Luangwa (Site 10.1) at its confluence with the Zambezi River in at least a Category C ecological condition, in order to contribute appropriate flows to the Zambezi and on to Mozambique.

In terms of sites, this was interpreted as target FDECs as follows:

• Sites 2.1 and 3.1: maintain a Category A FDEC, which they have at present;• Site 12.1: maintain a Category A/B FDEC, which it has at present;• Sites 8.1 and 8.2: must not drop below FDEC category B (presently at A) and targeted as B;• Site 10.1: must not drop below FDEC category C (present at A/B) and targeted as C.

Under this scenario (Table 9.2 and Figure 9.2) the FDEC targets are met at all sites as shown by the symbols in the ‘Target FDEC’ column and the Predicted FDEC column to its right. For some sites, the scenario exceeds the required FDEC; Site 10.1, for instance, has a target FDEC of C but would achieve an A/B category albeit with some slight reduction of flows in both seasons.

The scenario causes some reductions in FDEC as can be seen by comparing the ‘Current FDEC’ and ‘Predicted FEDC’ columns. Sites HS1, 8.1, HS4, HS8, HS10, 8.2, HS11, HS17, 9.1 and HS12 all experience a drop in their FDEC category.

48


Site

Current ConfigurationTarget FDEC

Scenario Configuration

Current FDEC

Wet (Jan-

Apr) as % Nat

Dry (Aug-

Nov) as % Nat

Predicted FDEC

Wet (Jan-Apr) as %

Nat

Dry (Aug-Nov) as %

Nat

2.1 A 100.0 100.0 A A 100.0 100.03.1 A 100.0 100.0 A A 100.0 100.0

HS1 A 100.0 100.0 B B 79.0 86.0HS2 A 100.0 100.0 A 100.0 100.08.1 A 100.0 100.0 B A/B 81.9 88.1

HS4 A 100.0 100.0 A/B 88.4 92.54.1 D 95.3 35.5 D 95.3 35.54.2 B 97.8 70.1 B 97.8 70.1

HS3 A/B 98.7 82.9 A/B 98.7 82.91.2 A 100.0 100.0 A 100.0 100.07.1 A 100.0 100.0 A 100.0 100.0

HS5 A 100.0 99.0 A/B 89.3 92.4HS6 A 100.0 100.0 A 100.0 100.0HS8 A 100.0 99.1 A/B 90.5 92.75.1 A 100.0 100.0 A 100.0 100.0

HS7 A 100.0 100.0 A 100.0 100.0HS10 A 100.0 99.2 B A/B 88.0 90.4

6.1 A 100.0 100.0 A 100.0 100.02.2 A 100.0 100.0 A 100.0 100.0

HS9 A 99.6 97.1 A 99.6 97.18.2 A 99.9 99.0 B A/B 89.5 92.21.1 B 84.4 174.7 B 84.4 174.77.2 A/B 91.1 136.1 A/B 91.1 136.1

HS11 A 99.9 99.0 A/B 89.8 92.5HS17 A 99.6 100.5 A/B 90.3 94.5HS18 A 100.0 100.0 A 100.0 100.0

9.1 A 99.6 100.4 A/B 90.8 94.7HS12 A 99.6 100.4 A/B 91.0 94.711.1 A 100.0 100.0 A 100.0 100.0

HS14 A 100.0 100.0 A 100.0 100.0HS13 C 91.1 261.5 C 91.1 261.512.1 A/B 99.6 91.8 A/B A/B 99.6 91.812.2 D 97.8 40.1 D 97.8 40.1

HS15 D 74.5 511.2 D 74.5 511.214.1 B/C 98.1 62.9 B/C 98.1 62.9

HS16 D 60.7 529.9 D 60.7 529.915.1 D 84.2 451.5 D 84.2 451.515.2 D 82.5 466.7 D 82.5 466.710.1 A/B 95.7 145.0 C A/B 87.6 141.5

Table 9.2



49


Figure 9.2

Predicted FDECs for each of the EFlow sites to achieve the target FDECs stipulated for Scenario 2

9.3 SCENARIO 3: EASTERN PROVINCE WATER SUPPLY DAMSThe starting points for this scenario were the lists of existing and planned dams in this Province (Water Resources: Report Number 3 in this series). These provided some insight into why some sites were in a pristine or degraded condition, and helped guide the selection of future condition for some other tributaries that would be included in the scenario. There are 160 existing dams in the Districts in Eastern Province that are entirely in the Luangwa Basin:• Chipata: 68 existing; 15 planned• Lundazi: 31 existing; 14 planned• Nyimba: 4 existing; 21 planned• Petauke: 57 existing; 16 planned.

It was not possible to locate all of these and ascertain their nature and capacity, because most of the rivers mentioned could not be found on the GIS maps; capacities, design and operating rules were not specified, so the impact on the streams could not be specified precisely; and some Districts and/or their boundaries did not match with the available maps. Districts that had only small areas in the Luangwa Basin (Katete, Mambwe and Sinda) were excluded, because there was no indication of how many of their existing and planned dams lie within the Luangwa Basin.

The EFlows sites relevant to the Eastern Province scenario are 2.2, 4.1, 4.2, 5.1 and 6.1, with sites 8.2 and 9.1 on the mainstem being responders to flow alterations at these sites.

50


Three of these sites (2.2, 5.1, 6.1) still have natural or near-natural flows despite the small dams scattered in the Province at presently unknown sites. These dams appear to be for local fishing, gardening and similar. Site 4.1 is the only site with a substantial change to its flow regime, because of a water supply dam (Lundazi Dam) immediately upstream. At times this has reduced dry-season flows to zero (Figure 6.1). This site is categorised as a D in terms of its current FDEC with zero flows in the some parts of the dry season in recent years. For instance, in 2010 flows ranged from zero in August and September to around 45% of natural for October and November.

Although monthly flows were higher in 2012, percentage flows ranged from zero midway through the dry season (August and September) to 60% of the natural regime towards the end of the dry season (October and November) in 2012. Site 4.2 reflected some downstream recovery of the flow regime, with about 65-75% of its natural flow regime present at the start of the dry season (June and July 2012) and about 55% of its natural flow regime towards mid-dry season (August and September 2012), increasing to 80% of its natural flow regime at the end of the dry season (October and November 2012).

On average the dry season flows are about 70% of natural at Site 4.2. Therefore, besides the effects of Lundazi Dam, there is no evidence from the hydrological data to suggest that the small dams in this region have a significant impact on the flow regime, although they may have other effects such as on water quality.

In order to provide insights into how further water supply dams (or many small dams) could impact the mainstem Luangwa, this scenario included inserting hypothetical water supply dams upstream of Sites 2.2, 5.1 and 6.1. It was assumed that Sites 5.1 and 6.1 would be impacted to the same extent as Site 4.1, and that Site 2.2 would be impacted to the same extent as Site 4.2. Thus the target FDECs for this scenario were:• Site 2.2: target B (currently A);• Site 4.1: target D/E (currently D);• Site 4.2: target C (currently B);• Sites 5.1 and 6.1: target C (currently A).

Under this scenario (Table 9.3 and Figure 9.3) the FDEC targets are not met at all sites due to the cumulative effects downstream of the proposed dams. At Site 4.2, although the target is a C condition, this is not achieved because the target of D/E at Site 4.16 reduces the cumulative flow at Site 4.2 to a predicted FDEC of D.

The condition at HS3 downstream of 4.2 is also reduced, from an A/B to a predicted FDEC of B/C. At Site 2.2 (downstream of Site 6.1) the target FDEC of a B is met, even though Site 6.1 upstream has a reduced condition (from a current FDEC of A to predicted FDEC of C). However both wet and dry season flows at Site 2.2 are reduced from natural and the wet season percentage of natural (69.5%) is only 0.5% above the threshold for a B/C and so, in effect, the predicted FDEC for Site 2.2 is a B/C.

6 Note that the D/E at Site 4.1 is a target in the sense that the predicted FDECs at Site 4.1 will be D/E as a result of the dam developments of this scenario.

51


Site



Current FDEC

Wet (Jan-

Apr) as % Nat

Dry (Aug-

Nov) as % Nat

Predicted FDEC

Wet (Jan-Apr) as %

Nat

Dry (Aug-Nov) as %

Nat

2.1 A 100.0 100.0 A 100.0 100.03.1 A 100.0 100.0 A 100.0 100.0

HS1 A 100.0 100.0 A 100.0 100.0HS2 A 100.0 100.0 A 100.0 100.08.1 A 100.0 100.0 A 100.0 100.0

HS4 A 100.0 100.0 A 100.0 100.04.1 D 95.3 35.5 D/E D/E 36.7 28.74.2 B 97.8 70.1 C D 49.5 43.6

HS3 A/B 98.7 82.9 B/C 71.1 67.71.2 A 100.0 100.0 A 100.0 100.07.1 A 100.0 100.0 A 100.0 100.0

HS5 A 100.0 99.0 A 98.6 98.2HS6 A 100.0 100.0 A 100.0 100.0HS8 A 100.0 99.1 A 98.8 98.25.1 A 100.0 100.0 C C 60.7 56.4

HS7 A 100.0 100.0 B 72.2 69.2HS10 A 100.0 99.2 A 98.3 97.6

6.1 A 100.0 100.0 C C 56.6 62.12.2 A 100.0 100.0 B B 69.5 77.2

HS9 A 99.6 97.1 A/B 91.6 91.38.2 A 99.9 99.0 A 97.7 97.01.1 B 84.4 174.7 B 84.4 174.77.2 A/B 91.1 136.1 A/B 91.1 136.1

HS11 A 99.9 99.0 A 97.8 97.1HS17 A 99.6 100.5 A 97.6 98.7HS18 A 100.0 100.0 A 100.0 100.0

9.1 A 99.6 100.4 A 97.7 98.8HS12 A 99.6 100.4 A 97.8 98.811.1 A 100.0 100.0 A 100.0 100.0

HS14 A 100.0 100.0 A 100.0 100.0HS13 C 91.1 261.5 C 91.1 261.512.1 A/B 99.6 91.8 A/B 99.6 91.812.2 D 97.8 40.1 D 97.8 40.1

HS15 D 74.5 511.2 D 74.5 511.214.1 B/C 98.1 62.9 B/C 98.1 62.9

HS16 D 60.7 529.9 D 60.7 529.915.1 D 84.2 451.5 D 84.2 451.515.2 D 82.5 466.7 D 82.5 466.710.1 A/B 95.7 145.0 A/B 94.6 143.7

Table 9.3



52


Figure 9.3


9.4 SCENARIO 4: MUCHINGA PROVINCE SMALL DAMSMuchinga is a relatively new Province and spatial information of its boundary or Districts were not available. It has 15 existing dams, but one of its districts (Mafinga) could not be located, and the coordinates for all dams were given in a range of formats that were not obviously decipherable.

It has 48 planned dams, all with good coordinates, which were plotted using GIS. This showed that the sites likely to be affected by the dams were 1.2, 2.1 and 3.1. The first two are situated in the vicinity of the greater number of planned dams, so in the scenario their target FDEC was dropped by two levels. Far fewer planned dams were located in the vicinity of Site 3.1 and therefore its target FDEC was dropped by one level, thus:• Site 1.2: target C (currently A);• Site 2.1: target C (currently A);• Site 3.1: target B (currently A).

Under this scenario (Table 9.4, Figure 9.4) the FDEC targets are met at all sites. Slight reductions in predicted FDEC occur at other sites: for example, Sites 8.1 and 8.2 are reduced from their current FDEC of As to predicted FDECs of A/B.

53


Site



Current FDEC

Wet (Jan-

Apr) as % Nat

Dry (Aug-

Nov) as % Nat

Predicted FDEC

Wet (Jan-Apr) as %

Nat

Dry (Aug-Nov) as %

Nat

2.1 A 100.0 100.0 C C 53.5 61.13.1 A 100.0 100.0 B B 70.0 80.9

HS1 A 100.0 100.0 A/B 86.8 89.2HS2 A 100.0 100.0 A 97.6 98.58.1 A 100.0 100.0 A/B 88.3 90.6

HS4 A 100.0 100.0 A/B 92.5 94.14.1 D 95.3 35.5 D 95.3 35.54.2 B 97.8 70.1 B 97.8 70.1

HS3 A/B 98.7 82.9 A/B 98.7 82.91.2 A 100.0 100.0 C C 57.4 59.17.1 A 100.0 100.0 A/B 82.8 83.5

HS5 A 100.0 99.0 A/B 93.1 93.7HS6 A 100.0 100.0 A/B 82.8 83.5HS8 A 100.0 99.1 A/B 92.3 93.85.1 A 100.0 100.0 A 100.0 100.0

HS7 A 100.0 100.0 A 100.0 100.0HS10 A 100.0 99.2 A/B 93.3 94.8

6.1 A 100.0 100.0 A 100.0 100.02.2 A 100.0 100.0 A 100.0 100.0

HS9 A 99.6 97.1 A 99.6 97.18.2 A 99.9 99.0 A/B 93.9 95.01.1 B 84.4 174.7 B 84.4 174.77.2 A/B 91.1 136.1 A/B 91.1 136.1

HS11 A 99.9 99.0 A/B 94.1 95.2HS17 A 99.6 100.5 A/B 94.2 96.9HS18 A 100.0 100.0 A 100.0 100.0

9.1 A 99.6 100.4 A/B 94.5 97.1HS12 A 99.6 100.4 A/B 94.7 97.111.1 A 100.0 100.0 A 100.0 100.0

HS14 A 100.0 100.0 A 100.0 100.0HS13 C 91.1 261.5 C 91.1 261.512.1 A/B 99.6 91.8 A/B 99.6 91.812.2 D 97.8 40.1 D 97.8 40.1

HS15 D 74.5 511.2 D 74.5 511.214.1 B/C 98.1 62.9 B/C 98.1 62.9

HS16 D 60.7 529.9 D 60.7 529.915.1 D 84.2 451.5 D 84.2 451.515.2 D 82.5 466.7 D 82.5 466.710.1 A/B 95.7 145.0 A/B 92.7 142.5

Table 9.4



54


Figure 9.4


9.5 SCENARIO 5: HYDROPOWERAll existing hydropower dams are on the western side of the basin. Two dams, Mita Hills Dam on the Lunsemfwa River and Mulungushi Dam on the Mulungushi River are operated by the Lunsemfwa Power Company. The Lusiwasi Dam, operated by ZESCO, is situated on the Lusiwasi River. It is planned to increase power generation on the Lunsemfwa system by an order of magnitude, from 56 MW to 500 MW. ZESCO plans to increase power generation on the Lusiwasi from 12 MW to 98 MW (Figure 9.5).

9.5.1 LunsemfwaThe existing dam at Mita Hills has changed flows at Site 15.1 dramatically (Figure 6.6). The changes have been mostly an increase in flows in the dry season: the operators appear to store wet-season water for release in the dry months, presumably to maintain power generation at roughly the same level throughout the year in all years (approximately 65-70 MCM). This means that in drought years, the flows arriving at Site 15.1 are similar from month to month (i.e. between 65-70 MCM) but in average years, large wet season flows are released such that the natural and current flow regimes are similar during peak discharge (February) with increased discharge (approximately 500% increase in some months) during the dry season. Storage seems to occur at the onset of the wet season (January) when discharge is lower than natural at Site 5.1.

55


Figure 9.5

The 21 EFlows sites and 18 hydro-sites (HS) used

in the Basin Configuration Model, with details of

some dams

The rules for assigning a FDEC category to a site with above natural flows are given in Table 6.1. Flows downstream of Mita Hills Dam are already 500% higher at the end of the dry season (i.e. November), placing this site’s flows regime at a seriously modified FDEC Category D. Considering the proposed 10-fold increase in power generation on the Lunsemfwa upstream of Site 15.1 and that the new scheme will be large and able to store even the peak discharges (February), the existing dry season monthly releases for a drought year (e.g. 2001) were doubled for this scenario. Based on these assumed flow increases, the percentage monthly increases relative to natural flows in the dry season would be approximately 1500% of natural reducing the river system at this point in this scenario to a FDEC category E.

9.5.2 LusiwasiSite 1.1 reflects operation of the Lusiwasi HEP Dam upstream. Its flows are about 150% of natural during the dry season except for November when it drops to 70% of natural, suggesting that is reservoir has limited storage. Based on the change in flow from natural and using the guidelines above, Site 1.1 was accorded a present-day FDEC category B. In order to account for the projected increase in power generation the scenario took this dam closer to the operation of the Mita Hills Ddam, altering Site 1.1 from a flow regime that still showed an approximation of natural seasonal variation to one that had the same volume of flow every dry season month. To do this, 20 MCM was allocated to every dry season month of the year, taking its FDEC to E. Under this scenario (Table 9.5 and Figure 9.6) the FDEC targets are met at all sites, but this causes reduced FDECs at other sites. For example, HS13 is reduced from a current FDEC of C to a predicted C/D due to the developments affecting Site 15.1; Site 10.1 is reduced from a current FDEC of A/B to a predicted B/C due to the cumulative upstream impacts.

Dam Purpose ID Category Cap-MCM Ann Releas Catchment

Lundazi Municipal Supply 1 Physical 2 24.22 LZ01-1

New Proposed Dam Irrigation 9Physical - Not yet constructed

0 0 LS01

Muloba Irrigation 8 Dummy, 3 dams 3.19 15.91 LS01

Bushcut Irrigation 14 Physical 2.7 53.77 M

New Mwomoshi Dam Irrigation 15

Physical - Not yet constructed

0 0 L

Lusiwasi Hydro-Power 3 Physical 70 36 LW1-1

Lutembwe Municipal Supply 2 Dummy, 2

dams 4 12.48 LB01

Mulungushi Hydro-Power 13 Physical 850 496.41 MG01-2

Mita Hills Hydro-Power 10 Physical 958 1745.08 LS03

Lunchu (LUC) Municipal Supply 12 Physical 5.11 5.17 LUC01

Tembwe (MUN3) Irrigation 6 Dummy, 8 dams 19.66 58.1 MUN03

Munshiwemba (MUN2) Irrigation 5 Dummy, 8

dams 39.28 100.56 MUN02

Munshiwemba (MUN1) Irrigation 4 Dummy, 4

dams 6.96 25.24 MUN01

Mushimbili Municipal Supply 11 Physical 10 17.35 KAS01

Fulwe Irrigation 7 Physical 1.27 2.64 LS02

56


Site



Current FDEC

Wet (Jan-

Apr) as % Nat

Dry (Aug-

Nov) as % Nat

Predicted FDEC

Wet (Jan-Apr) as %

Nat

Dry (Aug-Nov) as %

Nat

2.1 A 100.0 100.0 A 100.0 100.03.1 A 100.0 100.0 A 100.0 100.0

HS1 A 100.0 100.0 A 100.0 100.0HS2 A 100.0 100.0 A 100.0 100.08.1 A 100.0 100.0 A 100.0 100.0

HS4 A 100.0 100.0 A 100.0 100.04.1 D 95.3 35.5 D 95.3 35.54.2 B 97.8 70.1 B 97.8 70.1

HS3 A/B 98.7 82.9 A/B 98.7 82.91.2 A 100.0 100.0 A 100.0 100.07.1 A 100.0 100.0 D/E D/E 86.8 4284.6

HS5 A 100.0 99.0 A 100.0 99.0HS6 A 100.0 100.0 D/E 86.8 4284.6HS8 A 100.0 99.1 A/B 98.7 144.05.1 A 100.0 100.0 A 100.0 100.0

HS7 A 100.0 100.0 A 100.0 100.0HS10 A 100.0 99.2 A/B 98.9 136.9

6.1 A 100.0 100.0 A 100.0 100.02.2 A 100.0 100.0 A 100.0 100.0

HS9 A 99.6 97.1 A 99.6 97.18.2 A 99.9 99.0 A/B 99.0 132.81.1 B 84.4 174.7 D D 62.5 611.47.2 A/B 91.1 136.1 D D 62.5 612.8

HS11 A 99.9 99.0 A/B 99.0 131.6HS17 A 99.6 100.5 A/B 97.7 147.1HS18 A 100.0 100.0 A 100.0 100.0

9.1 A 99.6 100.4 A/B 97.8 144.9HS12 A 99.6 100.4 A/B 97.9 144.911.1 A 100.0 100.0 A 100.0 100.0

HS14 A 100.0 100.0 A 100.0 100.0HS13 C 91.1 261.5 C/D 89.0 412.112.1 A/B 99.6 91.8 A/B 99.6 91.812.2 D 97.8 40.1 D 97.8 40.1HS15 D 74.5 511.2 D 74.5 511.214.1 B/C 98.1 62.9 B/C 98.1 62.9

HS16 D 60.7 529.9 D 60.7 529.915.1 D 84.2 451.5 D/E D/E 87.5 903.115.2 D 82.5 466.7 D/E 84.8 802.910.1 A/B 95.7 145.0 B/C 92.8 219.5

Table 9.5



57


Figure 9.6


9.6 SCENARIO 6: COMBINATION OF SCENARIOS 2 TO 5Scenario 6 included a combination of the four possible management scenarios described above. In the case where there was a conflict in FDEC targets for any given site between the non-negotiable targets (Scenario 2) and the other development related targets, then the non-negotiable target was selected In the case where there were conflicting targets between the other three scenarios, the lowest FDEC target was selected. Under Scenario 6 (Table 9.6 and Figure 9.7) the resulting FDECs predicted at a number of sites are lower than the scenario target FDECs or lower than its current FDEC. For example:

• Site 4.2 is reduced from a present C FDEC to a predicted D (see Scenario 3, Section 9.3);• HS13 is reduced from a present B/C to a predicted C/D (see Scenario 4, Section 9.4);• Site 15.2 is reduced from a present D to a predicted D/E (see Scenario 5, Section 9.5);

At Site 10.1 despite the upstream developments, the target of a C FDEC is exceeded (i.e. the predicted FDEC is a B/C although reduced from its existing A/B status. This is because the upstream developments in this scenario include both reductions and increases in flow. The overall results at 10.1 show wet season flows at 83% of natural, and dry season flows at 215 % of natural, which results in a predicted B/C FDEC.

58


Site



Current FDEC

Wet (Jan-

Apr) as % Nat

Dry (Aug-

Nov) as % Nat

Predicted FDEC

Wet (Jan-Apr) as %

Nat

Dry (Aug-Nov) as %

Nat

2.1 A 100.0 100.0 A A 100.0 100.03.1 A 100.0 100.0 A A 100.0 100.0

HS1 A 100.0 100.0 B B 79.0 86.0HS2 A 100.0 100.0 A 100.0 100.08.1 A 100.0 100.0 B A/B 81.9 88.1

HS4 A 100.0 100.0 A/B 88.4 92.54.1 D 95.3 35.5 D/E D/E 36.7 28.74.2 B 97.8 70.1 C D 49.5 43.6

HS3 A/B 98.7 82.9 B/C 71.1 67.71.2 A 100.0 100.0 C C 57.4 59.17.1 A 100.0 100.0 D/E D/E 69.6 4268.2

HS5 A 100.0 99.0 A/B 88.0 91.5HS6 A 100.0 100.0 D/E 69.6 4268.2HS8 A 100.0 99.1 A/B 86.5 136.55.1 A 100.0 100.0 C C 60.7 56.4

HS7 A 100.0 100.0 B 72.2 69.2HS10 A 100.0 99.2 B A/B 83.9 126.3

6.1 A 100.0 100.0 C C 56.6 62.12.2 A 100.0 100.0 B B 69.5 77.2

HS9 A 99.6 97.1 A/B 91.6 91.38.2 A 99.9 99.0 B A/B 85.1 123.81.1 B 84.4 174.7 D D 62.5 611.47.2 A/B 91.1 136.1 D D 62.5 612.8

HS11 A 99.9 99.0 A/B 85.6 122.9HS17 A 99.6 100.5 A/B 85.4 139.2HS18 A 100.0 100.0 A 100.0 100.0

9.1 A 99.6 100.4 A/B 86.1 137.4HS12 A 99.6 100.4 A/B 86.5 137.411.1 A 100.0 100.0 A 100.0 100.0

HS14 A 100.0 100.0 A 100.0 100.0HS13 C 91.1 261.5 C/D 89.0 412.112.1 A/B 99.6 91.8 A/B A/B 99.6 91.812.2 D 97.8 40.1 D 97.8 40.1

HS15 D 74.5 511.2 D 74.5 511.214.1 B/C 98.1 62.9 B/C 98.1 62.9

HS16 D 60.7 529.9 D 60.7 529.915.1 D 84.2 451.5 D/E D/E 87.5 903.115.2 D 82.5 466.7 D/E 84.8 802.910.1 A/B 95.7 145.0 C B/C 83.0 214.7

Table 9.6



59


Figure 9.7


9.7 COMPARISON OF SCENARIOS AND INTERPRETATION OF RESULTSThe summary of existing and predicted FDEC categories (Table 9.7 and Figure 9.8) reveals the parts of the basin that are most changed already or most vulnerable to change under the scenarios analysed. Site 4.1 on the Lundazi River already has a drastically altered flow regime due to a dam, as have the sites on the Lunsemfwa River for the same reason (Sites 12.2, 15.1 and 15.2).

The flows are predicted to not materially change at these sites, or to deteriorate further, under the analysed scenarios. Scenarios 3, 5 and 6 show the most additional modification to flows, mostly to tributaries.

60


Sites

Scenario 1:

Current

Scenario 2

Suggested non-

negotiables

Scenario 3

Eastern Province

Scenario 4

Muchinga escarpment

Scenario 5

Hydropower

Scenario 6

Amalgamation

2.1 A A A C A A

3.1 A A A B A A

HS1 A B A A/B A B

HS2 A A A A A A

8.1 A A/B A A/B A A/B

HS4 A A/B A A/B A A/B

4.1 D D D/E D D D/E

4.2 B B D B B D

HS3 A/B A/B A/B A/B A/B B/C

1.2 A A A C A C

7.1 A A A A/B D/E D/E

HS5 A A/B A A/B A A/B

HS6 A A A A/B D/E D/E

HS8 A A/B A A/B A/B A/B

5.1 A A C A A C

HS7 A A B A A B


6.1 A A C A A C

2.2 A A B A A B

HS9 A A A/B A A A/B

8.2 A A/B A A/B A/B A/B

1.1 B B B B D D

7.2 A/B A/B A/B A/B D D



HS18 A A A A A A

9.1 A A/B A A/B A/B A/B


11.1 A A A A A A

HS14 A A A A A A

HS13 C C C C C/D C/D

12.1 A/B A/B A/B A/B A/B A/B

12.2 D D D D D D

HS15 D D D D D D

14.1 B/C B/C B/C B/C B/C B/C

HS16 D D D D D D

15.1 D D D D D/E D/E

15.2 D D D D D/E D/E

10.1 A/B A/B A/B A/B B/C B/C

Table 9.7

Estimated FDEC resulting from the flow changes

under each scenario

61


Figure 9.8

All six scenarios showing predicted FDECs

The conversion of predicted FDEC to predicted overall ecological condition (EC) follows a similar pattern (Table 9.8 and Figure 9.9), with the overall EC dropping as low as category E in some places under scenarios 3, 5 and 6. Category E is largely recognised as representing unsustainable development.

62


Sites

Scenario 1:

Current

Scenario 2

Suggested non-

negotiables

Scenario 3

Eastern Province

Scenario 4

Muchinga escarpment

Scenario 5

Hydropower

Scenario 6

Amalgamation

2.1 B/C B/C B/C D B/C B/C

3.1 B B B C B B

HS1 B C B B/C B C

HS2 B B B B B B

8.1 B B/C B B/C B B/C

HS4 B B/C B B/C B B/C

4.1 C D D/E D D D/E

4.2 C C E C C E

HS3 B B C B B C

1.2 B B B D B D

7.1 A/B A/B A/B B E E

HS5 B B/C B B/C B B/C

HS6 B B B B/C E E

HS8 B B/C B B/C B/C B/C

5.1 B B D B B D

HS7 B B C B B C


6.1 C C D/E C C D/E

2.2 B/C B/C C B/C B/C C

HS9 B B B/C B B B/C

8.2 B B/C B B/C B/C B/C

1.1 B B B B D D

7.2 A/B A/B A/B A/B D D



HS18 B B B B B B

9.1 B B/C B B/C B/C B/C


11.1 B B B B B B

HS14 B B B B B B

HS13 B C C C C/D C/D

12.1 C/D C/D C/D C/D C/D C/D

12.2 C/D D D D D D

HS15 B/C D D D D D

14.1 C C C C C C

HS16 C/D D D D D D

15.1 B/C D D D D/E D/E

15.2 B/C D D D D/E D/E

10.1 B/C B/C B/C B/C C C

Table 9.8

Predicted overall ecological condition

(EC) resulting from the flow changes under each

scenario

63


Figure 9.9

All six scenarios showing predicted ecological

condition

The scenario results indicate that although some developments would have relatively small effects on the basin as a whole, Scenario 6 - which includes all the developments of Scenarios 2 to 5 – would cause significant changes to flow and ecological condition.

The largest changes would be due to the predicted increase in dry season monthly flows, linked to the hypothetical hydropower dams in Scenarios 5 and 6.

64


The scenarios focus on developments in the tributary sub-basins within the Luangwa Basin, but it is predicted that the important mainstem sites of 8.1, 8.2, 9.1 and 10.1 would also experience flow alterations and consequent loss of ecological condition. Site 10.1 is the most downstream site and would experience the cumulative result of all upstream flow changes for any given scenario.

Flow modifications through the scenarios would affect the dry season flows to a greater extent than the wet season flows (Figure 9.10). At the highest levels of development (i.e. scenario 5 and 6), wet season flows would remain above 80% of natural while dry season flows would increase to above 200% of natural.

Figure 9.10

Results of all scenarios at Site 10.1 expressed as

percentages of natural flows

65


The Basin Configuration Model provides a rapid indication of expected outcomes of possible basin development plans and can be used to explore further scenarios of interest.

The model is under development: at the moment, new FDEC levels that are thought to approximate a future development-related flow change can be inserted and the predicted outcomes in terms of flow and ecological condition across the basin produced.

This has been illustrated in this document for a range of new types and locations of dams. New areas of irrigated agriculture could similarly be explored as long as the monthly

hydrological changes they would likely trigger could be predicted in the way needed in the model.

Model development continues and in 2017 it is planned that new simulated hydrological sequences representing developments will automatically produce their consequent FDEC, rather than them being specified ad hoc as happened in this document (Section 9). This will streamline and further standardize the prediction process.

The model outcomes need to be assessed with an understanding of what the FDEC, PES and predicted EC categories A to E represent. A brief guide is that the A and B categories represent a higher and lower ‘conservation river’ and the C and D categories a higher and lower ‘working river’. Category E represents unsustainable development and is generally recognized globally as never to be a management target.

The specifics of what would change cannot be addressed in this rapid method, beyond what is described in Table 8.4; instead, a comprehensive EFlows Assessment, usually done as planning moves from the basin level to the project level, would provide these specifics in terms of predicted changes in, for instance, fisheries, wildlife, floodplains, and a range of expected impacts on people.

The whole discipline of EFlows recognizes that there is a trade-off between water resource development and water resource protection. As flows change, so does the ecological condition of the river, and so there are economic and social gains from development but also social and ecosystem losses due to environmental degradation.

One way of gaining an insight into the trade-offs between these dimensions is through an exploration of the ‘efficient frontier’ (Goodwin and Wright, 1998).

This frontier is found by plotting any two dimensions or criteria of a set of scenarios against each other, and finding the outer boundary (the ‘frontier’). Scenarios behind the frontier are less efficient, as a scenario could be found on the frontier which improves the situation in one or other dimension.

10. USINGTHE BASIN

CONFIGURATION MODEL

66


An example is shown in Figure 10.1, which plots the percentage of natural flows (X-axis) against FDEC. The plotted points are the average condition across all sites.

Figure 10.1

Results of scenarios expressed as percentages

of natural flows versus FDEC

67


The plot for wet season flows (left), shows that Scenarios 1, 2, 3, and 6 define the frontier, and Scenario 5 is the least efficient solution, with a high percentage of natural average wet season flow retained, but a low resulting FDEC as compared with Scenario 6.

Thus, from this perspective, a scenario high on the line between Scenario 3 or 6 would be a better solution than Scenario 5.

With respect to dry season flows (right), there is less differentiation between the scenarios, which form two groups: those with hydropower dams to the right of the plot, and those without to the left.

In this graph Scenario 6 is less efficient than Scenario 5. An exploration of the features of the scenarios that are driving their place on the plots could reveal useful modifications for consideration in planning.

A note of caution however: an efficient frontier analysis is a means of exploring options rather than choosing, because (1) the scenarios on the frontier depend on which dimensions are plotted and (2) scenarios that are slightly behind the frontier may still be preferable, as they may be less extreme in one or other dimension (e.g. Scenario 4 might be preferable to Scenario 3 (on the frontier)). This analysis could be done for any of the sites and compared to any conservation or other targets specified for them.

The suggested non-negotiable for Site 10.1, for example, was an ecological condition C, which, in this coarse assessment, would be met by all the scenarios examined here.

The EFlows Basin Configuration Model is a tool that can be used in coarse-scale basin planning in data-poor situations. Its inputs are all coarse estimates with varying levels of verification. Important points to note are as follows:

• The hydrological data are the basis of all EFlow Assessments. For the Luangwa, Report number 4 in this series explains the limitations of the hydrological modelling, such as the use of a single observed daily

record (historical) to disaggregate the monthly flow volumes for all 21 EFlow sites to daily flows.• The estimates of current ecological condition (PES) were based almost entirely on general impressions of the team of the conditions at the sites or, where no-one had personal knowledge of the sites, on consideration of the level of human population and land-use in their drainage areas.• It was assumed that the same PES value held throughout the relevant Homogeneous Unit, whereas local conditions could well differ. This might be why some PES values were higher than the accompanying FDEC.• The EFlows tables in Appendix A are estimates; in particular, there is little guidance from the international literature on the category of ecological condition linked to declining volumes of natural floods.

11.CONCLUSION

68


12.1 PREPARE FOR HAND OVERThe EFlows Basin Configuration Model has been pushed beyond its original format for this project.

An early part of Phase 2 should be to ensure it is formalized and running smoothly; to finalise

setting it up for the Luangwa Basin, for hand over to WWF and WARMA; and to prepare a short simple User Manual based on this document.

A second part of such a document could be a guide to a generalized set of activities that would allow the model to be set up for any other basin.

12.2 TRAINING AND FURTHER SCENARIO ANALYSISTools such as this model often trigger a further round of investigations of development options not considered in the first application. These might include moving the scenario dams to a different part of the basin or changing the scale of contemplated irrigated agricultural expansion.

It is recommended that potential users of the model be trained to use the model and interpret its outputs. This should be a fairly easy and quick set of training, for instance, a hydrologist or river ecologist.

12.3 FIELD DATA AND ENHANCED MODELLINGThe assumptions made in developing this model for the Luangwa Basin are many and varied, and have been explained throughout the document.

12.RECOMMENDATIONS

• There is no international guidance on the impacts of above-natural flows on ecological condition, and the estimates in Section 7.6 of this document are a first attempt.• The selected future FDECs for each scenario were estimates based on existing similar levels of development in the basin, as described in Section 9, with no on-site experience.

The use of FDEC rather than PES in this model circumvented, to some extent, the lack of detailed knowledge of PES, replacing the largely unknown ecological condition with hydrological simulations and analysis based on accepted modelling techniques. In line with its rapid assessment status, the model uses simulated monthly flows rather than daily flows.

It is therefore unable to detect or account for impacts occurring at the daily level such as peaking hydropower releases or changes in flood hydrographs. For this reason, it is essential that once this first level of basin-level planning has been done, then a holistic EFlows Assessment method be used to produce detailed predictions of the social, ecological and economic implications of individual projects (see Recommendations).

69


Goodwin P and G. Wright. 1998. Decision analysis for management judgement. John Wiley & Sons, Chichester, England.

Hughes, D.A. and P. Hannart. 2003. A desktop model used to provide an initial estimate of the ecological instream flow requirements of rivers in South Africa. Journal of Hydrology 270, 167-181.

Hughes, D.A. and F. Münster. 1999. Hydrological quantification of the quality component for

the desktop model. Resource Directed Measures for Protection of Water Resources: River Ecosystems. Department of Water Affairs and Forestry.

King, J.M. 2012. Establishing the process for developing and implementing environmental flows for the Zambezi Basin. WWF project number 9FO83801. 139 pp.

King J and C. Brown. 2014. Determination of holding Environmental Flow requirements for the Upper and Middle Kafue River. Report Nr GFA/B5/2013. Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) GmbH, Lusaka. 93 pp.

Kleynhans C.J., M.D. Louw and M. Graham. 2008. Module G: EcoClassification and EcoStatus determination in River EcoClassification: Index of Habitat Integrity (Section 1, Technical manual). Joint Water Research Commission and Department of Water Affairs and Forestry report. WRC Report No. TT 377-08.

13.REFERENCES

Phase 2 of the Integrated Flow Assessment for the Luangwa Basin should include a structured programme of field data collection, improved hydrological modelling, on-site assessment of the PES of each site and setting up of an hydraulic model for the mainstem floodplains associated with the South Luangwa and/or North Luangwa National Parks.

70


APPE

NDIX

A.

A PER

CENT

AGES

OF NA

TURA

L MON

THLY

FLOWS

RECO

MMEN

DED T

O SU

STAIN

THE 2

1 EFLO

WS SI

TES A

ND 18

HYDR

OLOG

ICAL S

ITES I

N SP

ECIFI

ED FL

OW CO

NDITI

ONS (

FDEC

).S

ite

FD

EC

Oct

Nov

Dec

Jan

Feb

Mar

Ap

rM

ayJu

nJu

lA

ug

Sep

2.1

A/B

98

97

83

798

08

079

80

80

80

88

96

2.1

B8

48

272

69

706

96

96

970

68

758

2

2.1

BC

7271

636

061

616

061

6158

64

70

2.1

C63

62

5653

5454

5354

5451

576

2

2.1

CD

5655

49

474

847

4747

48

45

5054

2.1

D4

94

84

34

14

24

14

14

14

24

04

44

8

HS1

A/B

98

97

7778

83

82

7877

768

08

89

6

HS1

B8

48

26

86

873

716

86

76

66

875

82

HS1

BC

7271

60

60

64

636

059

5858

64

70

HS1

C63

62

5353

5655

5352

5251

576

2

HS1

CD

5655

46

4750

49

474

64

54

550

54

HS1

D4

94

84

04

14

34

24

14

04

04

04

44

8

8.1

A/B

98

97

7778

83

82

7877

768

08

89

6

8.1

B8

48

26

86

873

716

86

76

66

875

82

8.1

BC

7271

60

60

64

636

059

5858

64

70

8.1

C63

62

5353

5655

5352

5251

576

2

8.1

CD

5655

46

4750

49

474

64

54

550

54

71


Sit

eF

DE

CO

ctN

ovD

ecJa

nF

ebM

arA

pr

May

Jun

Jul

Au

gS

ep

8.1

D4

94

84

04

14

34

24

14

04

04

04

44

8

HS

4A

/B9

89

778

798

48

279

7776

80

88

96

HS

4B

84

82

68

69

7372

69

68

67

68

758

2

HS

4B

C72

716

061

65

6361

60

5958

64

70

HS

4C

636

253

5457

5654

5352

5157

62

HS

4C

D56

5547

4750

49

474

64

64

550

54

HS

4D

49

48

41

41

44

43

41

41

40

40

44

48

HS

5A

/B9

89

78

08

18

58

48

179

788

08

89

6

HS

5B

84

82

7171

7574

7170

706

875

82

HS

5B

C72

7163

64

67

66

64

636

258

64

70

HS

5C

636

256

5659

5856

5555

5157

62

HS

5C

D56

554

94

952

514

94

94

84

550

54

HS

5D

49

48

43

43

45

45

43

42

42

40

44

48

HS

8A

/B9

89

78

08

18

58

48

179

788

08

89

6

HS

8B

84

82

7171

7574

7170

706

875

82

HS

8B

C72

7163

64

67

66

64

636

258

64

70

HS

8C

636

256

5659

5856

5555

5157

62

HS

8C

D56

554

94

952

514

94

94

84

550

54

HS

8D

49

48

43

43

45

44

43

42

42

40

44

48

72


Sit

eF

DE

CO

ctN

ovD

ecJa

nF

ebM

arA

pr

May

Jun

Jul

Au

gS

ep

8.2

A/B

98

97

80

80

84

83

81

7979

80

88

96

8.2

B8

48

271

7175

7472

7070

68

758

2

8.2

BC

7271

6363

67

66

64

636

258

64

70

8.2

C63

62

5656

5958

5656

5551

576

2

8.2

CD

5655

49

49

5251

504

94

84

550

54

8.2

D4

94

84

34

34

54

44

34

24

24

04

44

8

HS1

0A

/B9

89

78

08

08

48

38

179

798

08

89

6

HS1

0B

83

81

7171

7473

7170

69

67

748

1

HS1

0B

C71

7063

636

66

563

62

62

586

46

9

HS1

0C

636

256

5658

5756

5555

5156

61

HS1

0C

D55

544

94

951

504

94

84

84

54

954

HS1

0D

48

48

43

43

45

44

43

42

42

394

347

HS1

1A

/B9

89

78

079

84

82

81

7878

80

88

96

HS1

1B

84

82

7170

7473

716

970

68

758

2

HS1

1B

C72

7163

636

66

56

46

26

258

64

70

HS1

1C

636

256

5558

5756

5455

5157

62

HS1

1C

D56

554

94

951

504

94

84

84

550

54

HS1

1D

49

48

43

42

44

44

43

42

42

40

44

48

HS1

7A

/B9

89

78

079

84

82

81

7878

80

88

96

73


Sit

eF

DE

CO

ctN

ovD

ecJa

nF

ebM

arA

pr

May

Jun

Jul

Au

gS

ep

HS1

7B

84

82

7170

7473

716

970

68

758

2

HS1

7B

C72

7163

636

66

56

46

26

258

64

70

HS1

7C

636

256

5558

5756

5455

5157

62

HS1

7C

D56

554

94

951

504

94

84

84

550

54

HS1

7D

49

48

43

42

44

44

43

42

42

40

44

48

9.1

A/B

98

97

80

80

84

83

80

7878

80

88

96

9.1

B8

48

271

7174

7371

69

69

68

758

2

9.1

BC

7271

6363

66

65

6361

62

586

470

9.1

C63

62

5656

5857

5654

5551

576

2

9.1

CD

5655

49

49

5150

49

48

48

45

5054

9.1

D4

94

84

34

34

54

44

34

14

24

04

44

8

HS1

2A

/B9

89

78

077

83

82

80

7677

80

88

96

HS1

2B

84

82

706

873

7270

67

68

68

758

2

HS1

2B

C72

716

26

06

46

46

26

06

058

64

70

HS1

2C

636

255

5357

5655

5353

5157

62

HS1

2C

D56

554

847

504

94

84

647

45

5054

HS1

2D

49

48

42

41

44

43

42

40

41

40

44

48

3.1

A/B

98

98

768

174

84

7678

7878

88

96

3.1

B8

48

36

872

66

746

86

96

96

675

82

74


Sit

eF

DE

CO

ctN

ovD

ecJa

nF

ebM

arA

pr

May

Jun

Jul

Au

gS

ep

3.1

BC

7272

60

64

596

661

62

62

576

470

3.1

C63

6353

5652

5854

5555

5057

62

3.1

CD

5655

4750

46

5147

48

48

44

5054

3.1

D4

94

94

14

34

04

54

14

24

239

44

48

HS

2A

/B9

89

779

80

84

83

80

7878

80

88

96

HS

2B

84

82

7070

7473

706

96

96

875

82

HS

2B

C72

716

263

66

65

6361

6158

64

70

HS

2C

636

255

5558

5755

5454

5157

62

HS

2C

D56

554

84

951

504

94

847

45

5054

HS

2D

49

48

42

42

45

44

42

42

41

40

44

48

4.1

A/B

96

97

89

728

18

18

179

84

718

29

3

4.1

B8

28

28

36

876

7676

7478

60

7079

4.1

BC

7070

7663

7070

706

873

5159

67

4.1

C59

596

756

62

62

62

60

64

43

5057

4.1

CD

5050

584

954

5454

5356

374

34

8

4.1

D4

34

350

42

46

46

46

45

48

3136

41

4.2

A/B

96

97

89

728

18

18

179

84

718

29

3

4.2

B8

28

28

36

876

7676

7478

60

7079

4.2

BC

7070

7663

7070

706

873

5159

67

75


Sit

eF

DE

CO

ctN

ovD

ecJa

nF

ebM

arA

pr

May

Jun

Jul

Au

gS

ep

4.2

C59

596

756

62

62

62

60

64

43

5057

4.2

CD

5050

584

954

5454

5356

374

34

8

4.2

D4

34

350

42

46

46

46

45

48

3136

41

HS

3A

/B9

69

78

975

81

798

08

18

471

82

93

HS

3B

82

82

83

7175

7475

7578

60

7079

HS

3B

C70

7076

66

706

96

970

7251

596

7

HS

3C

5959

67

586

26

061

62

64

43

5057

HS

3C

D50

5058

5154

5353

5455

374

34

8

HS

3D

43

43

504

34

64

54

64

647

3136

41

5.1

A/B

96

97

90

728

18

18

179

84

718

29

3

5.1

B8

28

28

36

876

7676

7479

60

7079

5.1

BC

7070

766

470

7070

69

7351

596

7

5.1

C59

596

756

62

62

62

616

44

350

57

5.1

CD

5050

584

954

5454

5356

374

34

8

5.1

D4

34

350

42

46

46

46

45

48

3136

41

HS

7A

/B9

69

78

971

81

81

81

788

471

82

93

HS

7B

82

82

83

67

7575

7573

786

070

79

HS

7B

C70

7076

6370

7070

68

7251

596

7

HS

7C

60

60

67

566

26

26

26

06

44

451

58

76


Sit

eF

DE

CO

ctN

ovD

ecJa

nF

ebM

arA

pr

May

Jun

Jul

Au

gS

ep

HS

7C

D52

5258

49

5454

5452

5638

44

49

HS

7D

46

46

514

247

4747

45

48

3439

45

10.1

A/B

98

97

7675

798

079

80

788

08

89

6

10.1

B8

48

26

66

56

96

96

96

96

86

875

82

10.1

BC

7271

5857

60

616

061

60

586

470

10.1

C63

62

5150

5354

5354

5251

576

2

10.1

CD

5655

45

44

4747

4747

46

45

5054

10.1

D4

94

84

039

41

41

41

41

40

40

44

48

11.1

A/B

97

96

7878

82

80

80

82

87

93

96

96

11.1

B8

28

26

76

771

7070

7176

798

28

2

11.1

BC

7170

5959

62

6161

62

66

68

7070

11.1

C6

26

252

5255

5454

5558

60

62

62

11.1

CD

5554

46

46

48

4747

48

5153

5454

11.1

D4

84

84

04

04

24

14

14

24

54

64

84

8

1.1

A/B

97

96

83

798

38

28

08

38

89

39

69

6

1.1

B8

28

26

958

65

64

616

26

779

82

82

1.1

BC

7171

60

5157

5654

5559

68

7070

1.1

C6

26

253

45

504

94

84

852

60

62

62

1.1

CD

5555

474

04

44

34

24

24

653

5454

77


Sit

eF

DE

CO

ctN

ovD

ecJa

nF

ebM

arA

pr

May

Jun

Jul

Au

gS

ep

1.1

D4

84

84

135

3938

3737

40

46

48

48

1.2

A/B

96

97

85

778

28

18

08

08

49

39

69

6

1.2

B8

28

277

7075

7472

7376

798

28

2

1.2

BC

69

7070

636

76

76

56

66

96

76

96

9

1.2

C59

60

6155

5958

5757

60

5759

59

1.2

CD

5051

524

851

504

950

524

950

50

1.2

D4

34

34

54

14

34

34

24

24

44

14

34

3

7.1

A/B

97

97

85

778

28

18

08

08

49

39

69

6

7.1

B8

28

277

7075

7472

7376

798

28

2

7.1

BC

7070

7063

67

67

65

66

69

67

69

69

7.1

C6

06

061

5559

5857

576

057

5959

7.1

CD

5151

524

851

504

950

524

950

50

7.1

D4

34

34

54

14

34

34

24

24

44

14

34

3

HS

6A

/B9

79

78

577

82

81

80

80

84

93

96

96

HS

6B

82

82

7770

7574

7273

7679

82

82

HS

6B

C70

7070

636

86

76

56

66

96

76

96

9

HS

6C

60

60

6155

5958

5757

60

5759

59

HS

6C

D51

5152

48

5150

49

5052

49

5050

HS

6D

43

43

45

41

43

43

42

42

44

41

43

43

78


Sit

eF

DE

CO

ctN

ovD

ecJa

nF

ebM

arA

pr

May

Jun

Jul

Au

gS

ep

7.2

A/B

97

96

83

788

38

379

81

84

93

96

96

7.2

B8

28

274

7073

7370

7275

798

28

2

7.2

BC

706

96

56

26

56

56

26

46

66

76

96

9

7.2

C6

059

5754

5656

5455

5757

5959

7.2

CD

5151

49

46

49

49

474

84

94

951

51

7.2

D4

44

44

24

04

24

24

04

14

24

24

44

4

2.2

A/B

97

97

84

82

80

80

798

18

59

39

69

6

2.2

B8

28

276

7473

7371

7477

798

28

2

2.2

BC

7171

69

67

66

66

65

67

69

68

7070

2.2

C6

26

261

60

5858

5759

616

06

26

2

2.2

CD

5555

5352

5151

5052

5453

5454

2.2

D4

84

84

64

54

44

44

44

547

46

48

48

6.1

A/B

97

97

84

7279

80

798

18

59

39

69

6

6.1

B8

28

276

66

7272

7174

7779

82

82

6.1

BC

7171

69

60

65

66

65

67

69

68

7070

6.1

C6

26

261

5358

5857

5961

60

62

62

6.1

CD

5555

5347

5151

5052

5453

5454

6.1

D4

84

84

64

04

44

44

44

547

46

48

48

HS

9A

/B9

79

78

48

38

28

279

82

85

88

90

90

79


Sit

eF

DE

CO

ctN

ovD

ecJa

nF

ebM

arA

pr

May

Jun

Jul

Au

gS

ep

HS

9B

81

81

7674

7373

7173

7674

7676

HS

9B

C6

96

96

86

76

66

66

46

66

963

64

64

HS

9C

60

60

60

5958

5856

586

054

5555

HS

9C

D52

5252

5151

514

951

5347

48

48

HS

9D

46

46

45

45

44

44

43

44

46

41

42

42

HS1

8A

/B9

79

78

472

798

079

82

85

93

96

96

HS1

8B

82

82

766

672

7271

7477

798

28

2

HS1

8B

C70

706

86

06

56

56

56

76

96

76

96

9

HS1

8C

60

60

60

5257

5756

586

057

5959

HS1

8C

D51

5152

45

49

49

49

5052

49

5050

HS1

8D

43

43

44

394

24

24

24

34

44

14

34

3

12.1

A/B

95

95

83

788

18

178

788

08

89

39

4

12.1

B8

18

172

68

7070

68

68

68

7579

80

12.1

BC

69

69

636

06

26

26

06

058

64

68

69

12.1

C61

6155

5354

5453

5351

576

06

0

12.1

CD

5454

49

46

48

48

46

46

45

5053

53

12.1

D47

474

34

04

24

24

04

04

04

44

647

12.2

A/B

95

95

83

788

18

178

788

08

89

39

4

12.2

B8

18

172

68

7070

68

68

68

7579

80

80


Sit

eF

DE

CO

ctN

ovD

ecJa

nF

ebM

arA

pr

May

Jun

Jul

Au

gS

ep

12.2

BC

69

69

636

06

26

26

06

058

64

68

69

12.2

C61

6156

5354

5453

5351

576

06

0

12.2

CD

5454

49

46

48

48

46

46

45

5053

53

12.2

D47

474

34

14

24

24

14

14

04

44

647

HS1

6A

/B9

49

591

718

176

80

86

88

88

93

94

HS1

6B

80

81

81

64

726

871

7678

7579

80

HS1

6B

C6

96

972

576

561

636

86

96

46

86

9

HS1

6C

596

06

250

5653

5559

60

5558

59

HS1

6C

D53

5456

44

5047

49

5254

5053

53

HS1

6D

48

48

49

394

44

24

34

647

45

474

8

15.1

A/B

95

95

83

798

28

279

758

08

89

39

4

15.1

B8

18

173

69

7171

69

66

68

7579

80

15.1

BC

69

69

64

6163

6361

5858

64

68

69

15.1

C61

6156

5455

5554

5151

576

06

0

15.1

CD

5454

5047

49

49

474

54

550

5353

15.1

D47

474

34

14

34

34

139

40

44

46

47

15.2

A/B

95

95

80

81

83

83

82

788

08

18

89

4

15.2

B8

18

171

7274

7373

706

86

975

80

15.2

BC

69

69

64

65

66

66

65

62

5859

64

69

81


Sit

eF

DE

CO

ctN

ovD

ecJa

nF

ebM

arA

pr

May

Jun

Jul

Au

gS

ep

15.2

C61

6156

5758

5857

5551

5257

60

15.2

CD

5454

49

5051

5150

48

45

46

5053

15.2

D47

474

34

44

54

44

44

24

04

04

447

14.1

A/B

95

90

90

80

83

81

83

87

768

89

39

4

14.1

B8

177

84

7477

7677

81

65

7579

80

14.1

BC

69

65

776

972

7072

7455

64

67

68

14.1

C58

556

861

636

263

65

4754

5758

14.1

CD

474

458

5354

5354

5637

43

46

46

14.1

D33

3147

44

45

44

45

46

2630

3232

HS1

5A

/B9

49

58

875

81

7779

85

90

88

93

94

HS1

5B

80

81

80

69

7571

7378

82

7579

80

HS1

5B

C6

86

973

64

68

65

67

7175

64

67

68

HS1

5C

5858

64

566

057

596

26

554

5758

HS1

5C

D4

647

544

851

49

5053

554

34

64

6

HS1

5D

3233

44

394

24

04

14

34

530

3232

HS1

3A

/B9

89

778

778

08

08

178

84

81

88

96

HS1

3B

84

82

69

68

7070

726

974

69

758

2

HS1

3B

C72

7161

616

26

263

616

659

64

70

HS1

3C

636

254

5355

5556

5458

5256

61

82


Sit

eF

DE

CO

ctN

ovD

ecJa

nF

ebM

arA

pr

May

Jun

Jul

Au

gS

ep

HS1

3C

D55

5447

474

84

84

947

514

54

954

HS1

3D

49

48

41

41

42

42

43

41

44

40

43

47

HS1

4A

/B9

59

477

788

08

18

078

84

81

88

94

HS1

4B

81

80

68

69

7071

706

874

69

758

0

HS1

4B

C6

96

96

061

62

636

26

06

559

64

69

HS1

4C

60

60

5253

5455

5453

5752

566

0

HS1

4C

D53

534

647

48

48

48

4750

45

49

53

HS1

4D

474

64

04

14

24

24

24

14

44

04

34

6

83


For more information, contact:

WWF-Zambia Country

Angeles Boulevard, P.O. Box 50551 RW, Long acres, Lusaka. ZAMBIA

TOURISM

HYDROLOGY

CHALLENGES

The South Luangwa National park generates approximately 27,000,000 USD per year in direct spending

Water availability is expected to decrease with the combined effects of climate change the current rhythm and scale of development

The Luangwa River contributes approximately 28Km3 of flow to the Zambezi River upstream of Cabora Bassa Dam

The Luangwa Basin

WW

F.PANDA.ORG W

WF TECHNICAL REPORT 2018

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Regular

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