THIS REPORT HAS BEEN PRODUCED IN COLLABORATION WITH
REPORT ZM 2018
Integrated Flow Assessment for the Luangwa River Zambia: Phase 1 BASIN CONFIGURATION OF EFLOWS BASED ON A RAPID BASIN PLANNING TOOL 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 WWF is one of the world’s largest and most experienced independent conservation organizations, with over 5 million supporters and a global Network active in more than 100 countries. WWF’s mission is to stop the degradation of the planet’s natural environment and to build a future in which humans live in harmony with nature, by: conserving the world’s biological diversity, ensuring that the use of renewable natural resources is sustainable, and promoting the reduction of pollution and wasteful consumption. While reasonable efforts have been made to ensure that the contents of this publication are factually correct and properly referenced, the findings, interpretations and conclusions expressed herein are those of the authors based on their scientific expertise and do not necessarily reflect the views of WWF. The boundaries, colors, denominations, and other information shown on any map in this work do not imply any judgement on the part of WWF concerning the legal status of any territory. BASIN CONFIGURATION OF EFLOWS BASED ON A RAPID BASIN PLANNING TOOL March 2018 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
CONTENTS
EXECUTIVE 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
4 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
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
5 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
This document is number 12 in a series of reports produced in Phase 1, in the series:
01 Inception Report 02 Luangwa Basin Division 03 Water Resources 04 Hydrology 05 Hydraulics 06 Fluvial Geomorphology 07 Water Quality 08 Vegetation 09 Invertebrates and Fish 10 Mammals, Birds and Herpetofauna 11 Resource Economics and Sociology 12 Basin Configuration of Eflows based on a Rapid Basin Planning Tool
6 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
The EFlows Basin Configuration Model is an Excel-based tool designed EXECUTIVE 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 SUMMARY 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 ALL DATA AND predicted the flow condition and ecological condition at each EFlow site under each scenario. The conditions were presented as a symbol, from A (pristine) INFORMATION to E (severely changed) for each site under each scenario. WERE COLLATED INTO A LIBRARY USING A REFERENCE MANAGEMENT SYSTEM KNOWN AS MENDELEY
7 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
Figure A The 21 EFlows sites (e.g. 15.2) and 18 hydrological sites (e.g. HS14) for the Luangwa Basin
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 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.
8 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
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.
9 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
1.1 BACKGROUND TO THE PROJECT WWF, in collaboration with Zambia’s 1. water management agency, WARMA, has launched a new initiative to address integrated flow management of the Luangwa Basin as part of a wider INTRODUCTION 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 ASSESSMENT The 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; THE FLOW REGIME • 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 IS A FUNDAMENTAL ecosystems; PART OF RIVERS • 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.
10 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
1.3 TERMS OF REFERENCE Task 1: Set up the EFlows Basin Configuration Model Set up the EFlows Basin Configuration Model using the hydrological model outputs created by the team’s hydrologists.
Task 2: Select sites and complete hydrological analyses Complete 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 Model Compile 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 output Select 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 outcome Run the six scenarios through the model. Write a report of the findings.
1.4 KEY DELIVERABLES AND REPORT LAYOUT This 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.
11 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
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 2. THE 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 CONCEPT 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.
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
12 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
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.
Table 2.1 Ecological Description of the habitat Definitions of the category Present Ecological State (PES) categories (after Kleynhans et al. 2008) A Unmodified. Still in a natural condition.
Near natural. A small change in natural habitats and biota has taken place B but the ecosystem functions are essentially unchanged.
Moderately modified. Loss and change of natural habitat and biota has C occurred, but the basic ecosystem functions are still predominantly unchanged.
Largely modified. A large loss of natural habitat, biota and basic D ecosystem functions has occurred.
Seriously modified. The loss of natural habitat, biota and basic ecosystem E functions is extensive.
Critically modified. The system has been critically modified with an almost complete loss of natural habitat and biota. In the worst instances, F basic ecosystem functions have been destroyed and the changes are irreversible.
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.
13 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
3.1 PRESENT ECOLOGICAL STATE (PES) The PES is the overall present ecological condition of a river site whether driven by flow or non- 3. DEFINITION 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 OF TERMS 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.
USED IN THIS 3.2 ENVIRONMENTAL FLOWS (EFLOWS) The monthly volumes of flow required to support a specific ecological condition.
3.4 FLOW-DRIVEN ECOLOGICAL DOCUMENT 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).
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 4. APPROACH 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.
14 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
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 5. SITE Company, ZAWA and WWF. Its main objectives were to:
• Divide the Luangwa Basin into relatively homogeneous biophysical and social areas; SELECTION • 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.
Figure 5.1 The 21 EFlows sites selected at the December 2015 workshop (Report 2 in this series)
15 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
Table 5.1 EFlows Site River Name HU PES Location of the 21 EFlows sites by HU and river and 1.1 Lusiwasi 1 B their estimated Present Ecological State (PES) 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
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.
16 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
6.1 NATURAL MONTHLY FLOWS FOR ALL 39 SITES Natural monthly data for the 21 EFlow 6. 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 HYDROLOGICAL 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 ANALYSES 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,
17 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
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).
18 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
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 Rule If seasonal flows are between FDEC Rules translating 1 95 and 102 % of natural, then the FDEC is: A seasonal percentages of 2 80 and 150 ” A/B natural flows to FDEC 3 69 and 200 ” B 4 61 and 250 ” B/C 5 53 and 300 ” C 6 47 and 450 ” C/D 7 35 and 800 ” D 8 28 and 1000 ” D/E 9 25 and 2000 ” E
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.
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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.
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).
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.
20 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
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.
21 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
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
22 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
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.
23 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
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.
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
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.
24 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
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 7. 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 COMPILATION 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 OF THE 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; EFLOWS 5. Combine flood and low-flow volumes per month in one table to produce a rapid EFlow
recommendation for each FDEC category.
TABLES 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.
25 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
Table 7.1 Natural Current Current and natural Homogeneous Hydrological Site River Unit MAR MAR Index (HI) Mean Annual Runoff (MCM) (MCM) (MAR), and the 2.1 Luangwa 2 870 870 4.0 Hydrological Index (HI), for the 39 sites (with sites 3.1 Luwumbu 3 41 41 6.7 arranged roughly in order HS1 Luangwa 8 3066 3066 3.9 from the headwaters to HS2 Luwumbu 8 509 509 6.2 the downstream end of 8.1 Luangwa 8 3575 3575 4.1 the basin) HS4 Luangwa 8 5603 5603 4.29 4.1 Lundazi 4 81 74 7.8 4.2 Lundazi 4 175 168 7.6 HS3 Lundazi 8 306 299 7.5 1.2 Munyamadzi 1 245 245 13.1 7.1 Munyamadzi 7 606 606 13.0
HS5 Luangwa 8 6197 6189 4.3
HS6 Munyamadzi 8 678 606 10.0 HS8 Luangwa 8 6951 6944 4.6 5.1 Lukusuzi 5 134 134 7.7 HS7 Lukusuzi 8 189 189 7.7 HS10 Luangwa 8 8041 8033 4.7 6.1 Msandile 6 55 55 7.4 2.2 Msandile 2 227 227 7.0 HS9 Lutembwe 8 866 862 7.1 8.2 Luangwa 8 8907 8896 4.5 1.1 Lusiwasi 1 208 197 3.4 7.2 Lusiwasi 7 365 353 5.0 HS11 Luangwa 8 9217 9206 4.5 HS17 Luangwa 8 10088 10065 4.4 HS18 Mvuvye 8 232 232 7.3 9.1 Luangwa 9 10611 10587 4.4 HS12 Luangwa 8 10877 10853 4.4 11.1 Lukusashi 11 870 870 4.1 HS13 Lunsemfwa 9 3095 3095 6.0 HS14 Lukusashi 11 6656 6432 4.9 12.1 Lunsemfwa 12 411 408 6.2 12.2 Lunsemfwa 12 1082 1025 6.2 HS15 Mulungushi 15 765 702 9.5 14.1 Mwomboshi 14 223 219 23.2 HS16 Mulungushi 12 486 427 7.9 15.1 Lunsemfwa 15 2430 2270 7.2 15.2 Lunsemfwa 15 3348 3124 7.7 10.1 Luangwa 10 17642 17395 4.8
26 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
7.2 SEPARATE NATURAL LOW- FLOW AND INTER-ANNUAL FLOOD VOLUMES As 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.
Table 7.2 % nMAR as Total volume Hydrological HI value, percentage and Site River inter-annual in inter-annual flood flows floods (MCM) Index (HI) volume of the natural MAR occurring as inter- 2.1 Luangwa 14.3 125 4.0 annual floods at each 3.1 Luwumbu 25.5 10 6.7 EFlows site 8.1 Luangwa 16 574 4.1 4.1 Lundazi 58.7 48 7.8 4.2 Lundazi 58.7 102 7.6 1.2 Munyamadzi 42.2 103 13.1 7.1 Munyamadzi 42.2 256 13.0 5.1 Lukusuzi 59 79 7.7 6.1 Msandile 38.9 21 7.4 2.2 Msandile 38.9 88 7.0 8.2 Luangwa 25.7 2291 4.5
1.1 Lusiwasi 14.7 31 3.4
7.2 Lusiwasi 26.7 98 5.0 9.1 Luangwa 24.4 2588 4.4 11.1 Lukusashi 10.9 95 4.1 12.1 Lunsemfwa 12.6 52 6.2 12.2 Lunsemfwa 13 141 6.2 14.1 Mwomboshi 62.4 149 23.2 15.1 Lunsemfwa 16.3 395 7.2 15.2 Lunsemfwa 27.3 913 7.7 10.1 Luangwa 12.6 2221 4.8
MCM = millions of cubic metres; nMAR = natural Mean Annual Runoff
27 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
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).
Table 7.3 EFlow Step Description Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep The allocation of water Process Separation Monthly volumes to dry (brown) of natural natural 1 volume 2.2 1.8- 4.6 17.4 74.2 77.1 24.6 8.3 5.7 4.5 3.6 2.8 and wet (blue) season flows (MCM)
months, using Site 2.2 as Percentage of inter-annual an example 2 flood volume 2 8 35 36 12 4 3 in each month (%)
Natural inter-annual 3 flood volume 1.9 7.3 30.9 32.1 10.3 3.4 2.4 (MCM)
Natural low flow and 4 intra-annual 2.2 1.8 2.7 10.2 43.3 45.0 14.4 4.8 3.3 4.5 3.6 2.8 flood volume (MCM)
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 CATEGORIES A 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.
28 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
Table 7.4 FDEC % of natural inter-annual flood volume The percent of natural remaining inter-annual flows A/B 99 apportioned to each B 95 FDEC B/C 90 C 80 C/D 70 D 60
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 % nMAR Total Volume allocated per FDEC (MCM) Inter-annual flood as volume EFlows inter- in volumes allocated to River annual inter- Site flood annual each EFlows site for each flows floods A/B B B/C C C/D D (MCM) FDEC category 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
29 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
Table 7.6 EFlow Step Description Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Table 7.6 repeated, Process with inter-annual flood Separation Monthly of natural natural 1 volume 2.2 1.8 4.6 17.4 74.2 77.1 24.6 8.3 5.7 4.5 3.6 2.8 volumes allocated in flows (MCM)
steps 5 and 6, using Site Percentage of inter-annual 2.2 and a Category A/B 2 flood volume 2 8 35 36 12 4 3 in each month FDEC as an example (%)
Natural inter-annual 3 flood volume 1.9 7.3 30.9 32.1 10.3 3.4 2.4 (MCM)
Natural low flow and intra-annual 4 flood volume 2.2 1.8 2.7 10.2 43.3 45.0 14.4 4.8 3.3 4.5 3.6 2.8 (MCM) (step 1-3)
Inter-annual flood % of natural 5 (step 3) for a 99 99 99 99 99 99 99 category A/B Calculation FDEC of floods Inter-annual flood volume 6 for a category 1.9 7.2 30.6 31.8 10.1 3.4 2.4 A/B FDEC (MCM)
7.4 CALCULATE LOW FLOWS AND INTRA-ANNUAL FLOODS FOR ALL FDEC CATEGORIES While 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).
30 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
• 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.
Table 7.7 Site 2.2 FDEC Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Monthly percentages Desktop output AB 104 105 73 23 34 30 34 49 65 78 90 100 from the Desktop Model Adjusted Desktop AB 97 97 73 70 67 67 64 69 75 93 96 96 output and the adjusted output output, to achieve an A/B FDEC at Site 2.2
31 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
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.
Table 7.8 EFlow Step Description Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep The allocation of water Process Separation Monthly volumes for monthly of natural natural 1 volume 2.2 1.8 4.6 17.4 74.2 77.1 24.6 8.3 5.7 4.5 3.6 2.8 low flows (steps 7 and flows (MCM)
8), using Site 2.2 as an Percentage of inter-annual example 2 flood volume 2 8 35 36 12 4 3 in each month (%)
Natural inter-annual 3 flood volume 1.9 7.3 30.9 32.1 10.3 3.4 2.4 (MCM)
Natural low flow and intra-annual 4 flood volume 2.2 1.8 2.7 10.2 43.3 45.0 14.4 4.8 3.3 4.5 3.6 2.8 (MCM) (step 1-3)
Inter-annual flood % of natural 5 (step 3) for a 99 99 99 99 99 99 99 category A/B Calculation FDEC of floods Inter-annual flood volume 6 for a category 1.9 7.2 30.6 31.8 10.1 3.4 2.4 A/B FDEC (MCM)
Low flow and intra-annual flood % of 7 natural for a 97 97 73 70 67 67 64 69 75 93 96 96 Calculation category A/B of low and FDEC intra- annual Low flow and flood flows intra-annual flood volume 8 for a category 2.2 1.7 2.0 7.1 29.0 30.1 9.2 3.3 2.5 4.2 3.5 2.7 A/B FDEC (MCM)
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).
32 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
Table 7.9 Percentage 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) Summary of the estimated FDEC EFlows recommendation Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep for the low and intra- 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 annual flood component 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 of the flow regime for all Luangwa sites, as a 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 percentage of monthly 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 natural flow, to support 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
specified FDECs 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
7.5 SUMMARISE OVERALL EFLOWS REQUIREMENT FOR EACH EFLOWS SITE The 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).
Table 7.10 EFlow Step Description Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep The total EFlows Process requirement for an A/B Separation Monthly of natural natural FDEC (steps 9 and 10), 1 volume 2.2 1.8 4.6 17.4 74.2 77.1 24.6 8.3 5.7 4.5 3.6 2.8 flows (MCM) using Site 2.2 as an Percentage of example inter-annual 2 flood volume 2 8 35 36 12 4 3 in each month (%)
Natural inter-annual 3 flood volume 1.9 7.3 30.9 32.1 10.3 3.4 2.4 (MCM)
Natural low flow and intra-annual 4 flood volume 2.2 1.8 2.7 10.2 43.3 45.0 14.4 4.8 3.3 4.5 3.6 2.8 (MCM) (step 1-3)
Inter-annual flood % of natural 5 (step 3) for a 99 99 99 99 99 99 99 category A/B Calculation FDEC of floods Inter-annual flood volume 6 for a category 1.9 7.2 30.6 31.8 10.1 3.4 2.4 A/B FDEC (MCM)
Low flow and intra-annual flood % of 7 natural for a 97 97 73 70 67 67 64 69 75 93 96 96 Calculation category A/B of low and FDEC intra- annual Low flow and flood flows intra-annual flood volume 8 for a category 2.2 1.7 2.0 7.1 29.0 30.1 9.2 3.3 2.5 4.2 3.5 2.7 A/B FDEC (MCM)
Total volume 9 for a category 2.2 1.7 3.9 14.3 59.6 61.9 19.3 6.7 4.9 4.2 3.5 2.7 A/B (MCM) Overall EFlow requirement Overall EFlow % of natural 80.3 80.3 10 for an A/B 97 97 84 82.1 79 81 85 93 96 96 category
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.
33 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
Table 7.11 Total recommended EFlow (% of natural MAR) for specified Natural FDECs Site River Names MAR The total annual EFlows Names (MCM) A/B B B/C C C/D D (including low flows, 2.1 Luangwa 870 80 70 61 54 47 42 intra-annual and 3.1 Luwumbu 41 80 71 63 56 49 43 inter-annual floods) recommended, as a 8.1 Luangwa 3575 81 70 62 55 48 42 percent of natural mean 4.1 Lundazi 81 81 75 69 61 53 45 annual flow, for all sites 4.2 Lundazi 175 81 75 69 61 53 45 and FDECs 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 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
34 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
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 MODEL The 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.
35 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
8.1 INTRODUCTION The EFlows Basin Configuration Model is an Excel-based tool designed for a first, low-resolution assessment of 8. THE EFLOWS 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 BASIN 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 CONFIGURATION made of their impact on the flow regime and ecological condition of the nearest downstream site and others further downstream likely to be affected. MODEL 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).
36 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
Table 8.1 Site Existing Existing River x-coordinate y-coordinate Coordinates, PES and Names PES FDEC FDEC for the 39 sites 2.1 Luangwa B/C A 33.0265 -10.251 3.1 Luwumbu B A 33.436 -10.767 HS1 Luangwa B A 32.8937 -11.109 HS2 Luwumbu B A 32.901 -11.111 8.1 Luangwa B A 32.8766 -11.184 HS4 Luangwa B A 32.3418 -12.063 4.1 Lundazi C D 33.1626 -12.271 4.2 Lundazi C B 32.7266 -12.181 HS3 Lundazi B A/B 32.342 -12.079 1.2 Munyamadzi B A 31.7152 -12.074 7.1 Munyamadzi A/B A 31.8016 -12.284 HS5 Luangwa B A 32.1465 -12.443 HS6 Munyamadzi B A 32.1403 -12.448 HS8 Luangwa B A 32.1231 -12.586 5.1 Lukusuzi B A 32.5111 -12.734 HS7 Lukusuzi B A 32.1256 -12.6 HS10 Luangwa B A 31.8398 -13.07 6.1 Msandile C A 32.4624 -13.392 2.2 Msandile B/C A 32.0769 -13.289 HS9 Lutembwe B A 31.8367 -13.085 8.2 Luangwa B A 31.8087 -13.084 1.1 Lusiwasi B B 31.0243 -13.186 7.2 Lusiwasi A/B A/B 31.2849 -13.429 HS11 Luangwa B A 31.3131 -13.514 HS17 Luangwa B A 30.8039 -14.032 HS18 Mvuvye B A 30.7938 -14.061 9.1 Luangwa B A 30.4632 -14.438 HS12 Luangwa B A 30.2192 -14.914 11.1 Lukusashi B A 30.6731 -13.606 HS13 Lunsemfwa B A 30.1997 -14.901 HS14 Lukusashi B C 29.9924 -14.611 12.1 Lunsemfwa C/D A/B 29.2353 -13.655 12.2 Lunsemfwa C/D D 29.1324 -13.935 HS15 Mulungushi B/C D 29.1701 -14.891 14.1 Mwomboshi C B/C 28.8421 -14.793 HS16 Mulungushi C/D D 28.8598 -14.778 15.1 Lunsemfwa B/C D 29.1848 -14.866 15.2 Lunsemfwa B/C D 29.6679 -14.748 10.1 Luangwa B/C A/B 30.2111 -14.995
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.
37 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
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
38 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
Table 8.2 Current Current Site Contributing Sites River Pre-scenario layout PES FDEC of the EFlows Basin 2.1 Luangwa B/C A Configuration Model sites 3.1 Luwumbu B A HS1 2.1 Luangwa B A HS2 3.1 Luwumbu B A 8.1 HS1 HS2 Luangwa B A HS4 8.1 Luangwa B A 4.1 Lundazi C D 4.2 4.1 Lundazi C B HS3 4.2 Lundazi B A/B 1.2 Munyamadzi B A 7.1 1.2 Munyamadzi A/B A HS5 HS3 HS4 Luangwa B A HS6 7.1 Munyamadzi B A HS8 HS5 HS6 Luangwa B A 5.1 Lukusuzi B A HS7 5.1 Lukusuzi B A HS10 HS7 HS8 Luangwa B A 6.1 Msandile C A 2.2 6.1 Msandile B/C A HS9 2.2 Lutembwe B A 8.2 HS9 HS10 Luangwa B A 1.1 Lusiwasi B B 7.2 1.1 Lusiwasi A/B A/B HS11 8.2 Luangwa B A HS17 HS11 7.2 Luangwa B A HS18 Mvuvye B A 9.1 HS17 HS18 Luangwa B A HS12 9.1 Luangwa B A 11.1 Lukusashi B A HS14 11.1 Lunsemfwa B A HS13 HS14 15.2 Lukusashi B B/C 12.1 Lunsemfwa C/D A/B 12.2 12.1 Lunsemfwa C/D C HS15 14.1 HS16 Mulungushi B/C D 14.1 Mwomboshi C B/C HS16 Mulugushi C/D D 15.1 12.2 Lunsemfwa B/C C/D 15.2 15.1 HS15 Lunsemfwa B/C D 10.1 HS13 HS12 Luangwa B/C A/B
39 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
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).
Table 8.3 A B C D E F Example of the Row Site Contributing FDEC Current Current Sites accumulation of flows in incremental cumulative the Basin Configuration flow (MCM) flow (MCM) Model for Sites 4.1, 4.2 1 4.1 D 73.7 73.7 and HS3 2 4.2 4.1 B 94.2 167.9 3 HS3 4.2 A/B 130.9 298.8
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
40 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
8.2 ASSESSMENT OF SCENARIOS AND THE ACHIEVEMENT OF TARGETS Scenario 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 Section of the EFlows Basin Configuration Model 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.
41 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
Figure 8.5 Section of the EFlows Basin Configuration Model 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 %.
42 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
Table 8.4 Overall % of Relationship Ecological Description of the habitat natural between scores in the category total score ecoclassification process (PES) and ecological categories A Unmodified. Still in a natural condition. >95 (adapted from Kleynhans A/B >90.5 et al. 2008) Near natural. A small change in natural habitats and B biota has taken place but the ecosystem functions >85 are essentially unchanged. B/C >80.5 Moderately modified. Loss and change of natural habitat and biota has occurred, but the basic C >70 ecosystem functions are still predominantly unchanged. C/D >60.5 Largely modified. A large loss of natural habitat, D >50 biota and basic ecosystem functions has occurred. D/E >40.5 Seriously modified. The loss of natural habitat, biota E >30 and basic ecosystem functions is extensive. E/F >20.5 Critically modified. An almost complete loss of natural habitat and biota. In the worst instances, F >0 basic ecosystem functions have been destroyed and the changes are irreversible.
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.
43 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
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.
44 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
With the model configured, scenarios were selected that could illustrate different possible permutations of basin development: • Baseline; 9. SCENARIO • Suggested non-negotiables; • Eastern Province water supply dams; • Muchinga Province small dams; • Hydropower in western basin; SELECTION • 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 AND ANALYSIS current FDEC.
9.1 SCENARIO 1: BASELINE – THE EXISTING SITUATION This 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.
Table 9.1 Current Configuration Scenario 1: current FDEC Site Wet (Jan-Apr) as Dry (Aug-Nov) as Current FDEC and seasonal flows as % Nat % Nat percentages of natural MAR 2.1 A 100.0 100.0 3.1 A 100.0 100.0 HS1 A 100.0 100.0 HS2 A 100.0 100.0 8.1 A 100.0 100.0 HS4 A 100.0 100.0 4.1 D 95.3 35.5 4.2 B 97.8 70.1 HS3 A/B 98.7 82.9 1.2 A 100.0 100.0 7.1 A 100.0 100.0 HS5 A 100.0 99.0 HS6 A 100.0 100.0 HS8 A 100.0 99.1 5.1 A 100.0 100.0 HS7 A 100.0 100.0 HS10 A 100.0 99.2 6.1 A 100.0 100.0 2.2 A 100.0 100.0 HS9 A 99.6 97.1 8.2 A 99.9 99.0 1.1 B 84.4 174.7 7.2 A/B 91.1 136.1
45 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
Current Configuration Site Wet (Jan-Apr) as Dry (Aug-Nov) as Current FDEC % Nat % Nat HS11 A 99.9 99.0 HS17 A 99.6 100.5 HS18 A 100.0 100.0 9.1 A 99.6 100.4 HS12 A 99.6 100.4 11.1 A 100.0 100.0 HS14 A 100.0 100.0 HS13 C 91.1 261.5 12.1 A/B 99.6 91.8 12.2 D 97.8 40.1 HS15 D 74.5 511.2 14.1 B/C 98.1 62.9 HS16 D 60.7 529.9 15.1 D 84.2 451.5 15.2 D 82.5 466.7 10.1 A/B 95.7 145.0
Figure 9.1 Scenario 1: map of current FDEC for each of the EFlow sites
46 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
9.2 SCENARIO 2: SUGGESTED NON-NEGOTIABLES In 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.
47 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
Table 9.2 Current Configuration Scenario Configuration Scenario 2: current FDEC Wet Dry Target Site Predicted Wet (Jan- Dry (Aug- and seasonal flows as Current (Jan- (Aug- FDEC Apr) as % Nov) as % FDEC Apr) as Nov) as FDEC percentages of natural % Nat % Nat Nat Nat MAR 2.1 A 100.0 100.0 A A 100.0 100.0 3.1 A 100.0 100.0 A A 100.0 100.0 HS1 A 100.0 100.0 B B 79.0 86.0 HS2 A 100.0 100.0 A 100.0 100.0 8.1 A 100.0 100.0 B A/B 81.9 88.1 HS4 A 100.0 100.0 A/B 88.4 92.5 4.1 D 95.3 35.5 D 95.3 35.5 4.2 B 97.8 70.1 B 97.8 70.1 HS3 A/B 98.7 82.9 A/B 98.7 82.9 1.2 A 100.0 100.0 A 100.0 100.0 7.1 A 100.0 100.0 A 100.0 100.0 HS5 A 100.0 99.0 A/B 89.3 92.4 HS6 A 100.0 100.0 A 100.0 100.0 HS8 A 100.0 99.1 A/B 90.5 92.7 5.1 A 100.0 100.0 A 100.0 100.0 HS7 A 100.0 100.0 A 100.0 100.0 HS10 A 100.0 99.2 B A/B 88.0 90.4 6.1 A 100.0 100.0 A 100.0 100.0 2.2 A 100.0 100.0 A 100.0 100.0 HS9 A 99.6 97.1 A 99.6 97.1 8.2 A 99.9 99.0 B A/B 89.5 92.2 1.1 B 84.4 174.7 B 84.4 174.7 7.2 A/B 91.1 136.1 A/B 91.1 136.1 HS11 A 99.9 99.0 A/B 89.8 92.5 HS17 A 99.6 100.5 A/B 90.3 94.5 HS18 A 100.0 100.0 A 100.0 100.0 9.1 A 99.6 100.4 A/B 90.8 94.7 HS12 A 99.6 100.4 A/B 91.0 94.7 11.1 A 100.0 100.0 A 100.0 100.0 HS14 A 100.0 100.0 A 100.0 100.0 HS13 C 91.1 261.5 C 91.1 261.5 12.1 A/B 99.6 91.8 A/B A/B 99.6 91.8 12.2 D 97.8 40.1 D 97.8 40.1 HS15 D 74.5 511.2 D 74.5 511.2 14.1 B/C 98.1 62.9 B/C 98.1 62.9 HS16 D 60.7 529.9 D 60.7 529.9 15.1 D 84.2 451.5 D 84.2 451.5 15.2 D 82.5 466.7 D 82.5 466.7 10.1 A/B 95.7 145.0 C A/B 87.6 141.5
48 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
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 DAMS The 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.
49 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
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.
50 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
Table 9.3 Current Configuration Scenario Configuration Scenario 3: current FDEC Wet Dry Target Site Predicted Wet (Jan- Dry (Aug- and seasonal flows as Current (Jan- (Aug- FDEC Apr) as % Nov) as % FDEC Apr) as Nov) as FDEC percentages of natural % Nat % Nat Nat Nat MAR 2.1 A 100.0 100.0 A 100.0 100.0 3.1 A 100.0 100.0 A 100.0 100.0 HS1 A 100.0 100.0 A 100.0 100.0 HS2 A 100.0 100.0 A 100.0 100.0 8.1 A 100.0 100.0 A 100.0 100.0 HS4 A 100.0 100.0 A 100.0 100.0 4.1 D 95.3 35.5 D/E D/E 36.7 28.7 4.2 B 97.8 70.1 C D 49.5 43.6 HS3 A/B 98.7 82.9 B/C 71.1 67.7 1.2 A 100.0 100.0 A 100.0 100.0 7.1 A 100.0 100.0 A 100.0 100.0 HS5 A 100.0 99.0 A 98.6 98.2 HS6 A 100.0 100.0 A 100.0 100.0 HS8 A 100.0 99.1 A 98.8 98.2 5.1 A 100.0 100.0 C C 60.7 56.4 HS7 A 100.0 100.0 B 72.2 69.2 HS10 A 100.0 99.2 A 98.3 97.6 6.1 A 100.0 100.0 C C 56.6 62.1 2.2 A 100.0 100.0 B B 69.5 77.2 HS9 A 99.6 97.1 A/B 91.6 91.3 8.2 A 99.9 99.0 A 97.7 97.0 1.1 B 84.4 174.7 B 84.4 174.7 7.2 A/B 91.1 136.1 A/B 91.1 136.1 HS11 A 99.9 99.0 A 97.8 97.1 HS17 A 99.6 100.5 A 97.6 98.7 HS18 A 100.0 100.0 A 100.0 100.0 9.1 A 99.6 100.4 A 97.7 98.8 HS12 A 99.6 100.4 A 97.8 98.8 11.1 A 100.0 100.0 A 100.0 100.0 HS14 A 100.0 100.0 A 100.0 100.0 HS13 C 91.1 261.5 C 91.1 261.5 12.1 A/B 99.6 91.8 A/B 99.6 91.8 12.2 D 97.8 40.1 D 97.8 40.1 HS15 D 74.5 511.2 D 74.5 511.2 14.1 B/C 98.1 62.9 B/C 98.1 62.9 HS16 D 60.7 529.9 D 60.7 529.9 15.1 D 84.2 451.5 D 84.2 451.5 15.2 D 82.5 466.7 D 82.5 466.7 10.1 A/B 95.7 145.0 A/B 94.6 143.7
51 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
Figure 9.3 Predicted FDECs for each of the EFlow sites to achieve the target FDECs stipulated for Scenario 3
9.4 SCENARIO 4: MUCHINGA PROVINCE SMALL DAMS Muchinga 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.
52 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
Table 9.4 Current Configuration Scenario Configuration Scenario 4: current FDEC Wet Dry Target Site Predicted Wet (Jan- Dry (Aug- and seasonal flows as Current (Jan- (Aug- FDEC Apr) as % Nov) as % FDEC Apr) as Nov) as FDEC percentages of natural % Nat % Nat Nat Nat MAR 2.1 A 100.0 100.0 C C 53.5 61.1 3.1 A 100.0 100.0 B B 70.0 80.9 HS1 A 100.0 100.0 A/B 86.8 89.2 HS2 A 100.0 100.0 A 97.6 98.5 8.1 A 100.0 100.0 A/B 88.3 90.6 HS4 A 100.0 100.0 A/B 92.5 94.1 4.1 D 95.3 35.5 D 95.3 35.5 4.2 B 97.8 70.1 B 97.8 70.1 HS3 A/B 98.7 82.9 A/B 98.7 82.9 1.2 A 100.0 100.0 C C 57.4 59.1 7.1 A 100.0 100.0 A/B 82.8 83.5 HS5 A 100.0 99.0 A/B 93.1 93.7 HS6 A 100.0 100.0 A/B 82.8 83.5 HS8 A 100.0 99.1 A/B 92.3 93.8 5.1 A 100.0 100.0 A 100.0 100.0 HS7 A 100.0 100.0 A 100.0 100.0 HS10 A 100.0 99.2 A/B 93.3 94.8 6.1 A 100.0 100.0 A 100.0 100.0 2.2 A 100.0 100.0 A 100.0 100.0 HS9 A 99.6 97.1 A 99.6 97.1 8.2 A 99.9 99.0 A/B 93.9 95.0 1.1 B 84.4 174.7 B 84.4 174.7 7.2 A/B 91.1 136.1 A/B 91.1 136.1 HS11 A 99.9 99.0 A/B 94.1 95.2 HS17 A 99.6 100.5 A/B 94.2 96.9 HS18 A 100.0 100.0 A 100.0 100.0 9.1 A 99.6 100.4 A/B 94.5 97.1 HS12 A 99.6 100.4 A/B 94.7 97.1 11.1 A 100.0 100.0 A 100.0 100.0 HS14 A 100.0 100.0 A 100.0 100.0 HS13 C 91.1 261.5 C 91.1 261.5 12.1 A/B 99.6 91.8 A/B 99.6 91.8 12.2 D 97.8 40.1 D 97.8 40.1 HS15 D 74.5 511.2 D 74.5 511.2 14.1 B/C 98.1 62.9 B/C 98.1 62.9 HS16 D 60.7 529.9 D 60.7 529.9 15.1 D 84.2 451.5 D 84.2 451.5 15.2 D 82.5 466.7 D 82.5 466.7 10.1 A/B 95.7 145.0 A/B 92.7 142.5
53 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
Figure 9.4 Predicted FDECs for each of the EFlow sites to achieve the target FDECs stipulated for Scenario 4
9.5 SCENARIO 5: HYDROPOWER All 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 Lunsemfwa The 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.
54 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
Ann Figure 9.5 Dam Purpose ID Category Cap-MCM Catchment Releas
Municipal Lundazi 1 Physical 2 24.22 LZ01-1 The 21 EFlows sites and Supply
18 hydro-sites (HS) used Physical New Proposed Dam Irrigation 9 - Not yet 0 0 LS01 in the Basin Configuration constructed Dummy, 3 Muloba Irrigation 8 3.19 15.91 LS01 Model, with details of dams some dams Bushcut Irrigation 14 Physical 2.7 53.77 M Physical New Mwomoshi Irrigation 15 - Not yet 0 0 L Dam constructed
Hydro- Lusiwasi 3 Physical 70 36 LW1-1 Power
Municipal Dummy, 2 Lutembwe 2 4 12.48 LB01 Supply dams
Hydro- Mulungushi 13 Physical 850 496.41 MG01-2 Power
Hydro- Mita Hills 10 Physical 958 1745.08 LS03 Power
Municipal Lunchu (LUC) 12 Physical 5.11 5.17 LUC01 Supply
Dummy, 8 Tembwe (MUN3) Irrigation 6 19.66 58.1 MUN03 dams
Munshiwemba Dummy, 8 Irrigation 5 39.28 100.56 MUN02 (MUN2) dams
Munshiwemba Dummy, 4 Irrigation 4 6.96 25.24 MUN01 (MUN1) dams
Municipal Mushimbili 11 Physical 10 17.35 KAS01 Supply
Fulwe Irrigation 7 Physical 1.27 2.64 LS02
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 Lusiwasi Site 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.
55 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
Table 9.5 Current Configuration Scenario Configuration Scenario 5: current FDEC Wet Dry Target Site Predicted Wet (Jan- Dry (Aug- and seasonal flows as Current (Jan- (Aug- FDEC Apr) as % Nov) as % FDEC Apr) as Nov) as FDEC percentages of natural % Nat % Nat Nat Nat MAR 2.1 A 100.0 100.0 A 100.0 100.0 3.1 A 100.0 100.0 A 100.0 100.0 HS1 A 100.0 100.0 A 100.0 100.0 HS2 A 100.0 100.0 A 100.0 100.0 8.1 A 100.0 100.0 A 100.0 100.0 HS4 A 100.0 100.0 A 100.0 100.0 4.1 D 95.3 35.5 D 95.3 35.5 4.2 B 97.8 70.1 B 97.8 70.1 HS3 A/B 98.7 82.9 A/B 98.7 82.9 1.2 A 100.0 100.0 A 100.0 100.0 7.1 A 100.0 100.0 D/E D/E 86.8 4284.6 HS5 A 100.0 99.0 A 100.0 99.0 HS6 A 100.0 100.0 D/E 86.8 4284.6 HS8 A 100.0 99.1 A/B 98.7 144.0 5.1 A 100.0 100.0 A 100.0 100.0 HS7 A 100.0 100.0 A 100.0 100.0 HS10 A 100.0 99.2 A/B 98.9 136.9 6.1 A 100.0 100.0 A 100.0 100.0 2.2 A 100.0 100.0 A 100.0 100.0 HS9 A 99.6 97.1 A 99.6 97.1 8.2 A 99.9 99.0 A/B 99.0 132.8 1.1 B 84.4 174.7 D D 62.5 611.4 7.2 A/B 91.1 136.1 D D 62.5 612.8 HS11 A 99.9 99.0 A/B 99.0 131.6 HS17 A 99.6 100.5 A/B 97.7 147.1 HS18 A 100.0 100.0 A 100.0 100.0 9.1 A 99.6 100.4 A/B 97.8 144.9 HS12 A 99.6 100.4 A/B 97.9 144.9 11.1 A 100.0 100.0 A 100.0 100.0 HS14 A 100.0 100.0 A 100.0 100.0 HS13 C 91.1 261.5 C/D 89.0 412.1 12.1 A/B 99.6 91.8 A/B 99.6 91.8 12.2 D 97.8 40.1 D 97.8 40.1 HS15 D 74.5 511.2 D 74.5 511.2 14.1 B/C 98.1 62.9 B/C 98.1 62.9 HS16 D 60.7 529.9 D 60.7 529.9 15.1 D 84.2 451.5 D/E D/E 87.5 903.1 15.2 D 82.5 466.7 D/E 84.8 802.9 10.1 A/B 95.7 145.0 B/C 92.8 219.5
56 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
Figure 9.6 Predicted FDECs for each of the EFlow sites to achieve the target FDECs stipulated for Scenario 5
9.6 SCENARIO 6: COMBINATION OF SCENARIOS 2 TO 5 Scenario 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.
57 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
Table 9.6 Current Configuration Scenario Configuration Scenario 6: current FDEC Wet Dry Target Site Predicted Wet (Jan- Dry (Aug- and seasonal flows as Current (Jan- (Aug- FDEC Apr) as % Nov) as % FDEC Apr) as Nov) as FDEC percentages of natural % Nat % Nat Nat Nat MAR 2.1 A 100.0 100.0 A A 100.0 100.0 3.1 A 100.0 100.0 A A 100.0 100.0 HS1 A 100.0 100.0 B B 79.0 86.0 HS2 A 100.0 100.0 A 100.0 100.0 8.1 A 100.0 100.0 B A/B 81.9 88.1 HS4 A 100.0 100.0 A/B 88.4 92.5 4.1 D 95.3 35.5 D/E D/E 36.7 28.7 4.2 B 97.8 70.1 C D 49.5 43.6 HS3 A/B 98.7 82.9 B/C 71.1 67.7 1.2 A 100.0 100.0 C C 57.4 59.1 7.1 A 100.0 100.0 D/E D/E 69.6 4268.2 HS5 A 100.0 99.0 A/B 88.0 91.5 HS6 A 100.0 100.0 D/E 69.6 4268.2 HS8 A 100.0 99.1 A/B 86.5 136.5 5.1 A 100.0 100.0 C C 60.7 56.4 HS7 A 100.0 100.0 B 72.2 69.2 HS10 A 100.0 99.2 B A/B 83.9 126.3 6.1 A 100.0 100.0 C C 56.6 62.1 2.2 A 100.0 100.0 B B 69.5 77.2 HS9 A 99.6 97.1 A/B 91.6 91.3 8.2 A 99.9 99.0 B A/B 85.1 123.8 1.1 B 84.4 174.7 D D 62.5 611.4 7.2 A/B 91.1 136.1 D D 62.5 612.8 HS11 A 99.9 99.0 A/B 85.6 122.9 HS17 A 99.6 100.5 A/B 85.4 139.2 HS18 A 100.0 100.0 A 100.0 100.0 9.1 A 99.6 100.4 A/B 86.1 137.4 HS12 A 99.6 100.4 A/B 86.5 137.4 11.1 A 100.0 100.0 A 100.0 100.0 HS14 A 100.0 100.0 A 100.0 100.0 HS13 C 91.1 261.5 C/D 89.0 412.1 12.1 A/B 99.6 91.8 A/B A/B 99.6 91.8 12.2 D 97.8 40.1 D 97.8 40.1 HS15 D 74.5 511.2 D 74.5 511.2 14.1 B/C 98.1 62.9 B/C 98.1 62.9 HS16 D 60.7 529.9 D 60.7 529.9 15.1 D 84.2 451.5 D/E D/E 87.5 903.1 15.2 D 82.5 466.7 D/E 84.8 802.9 10.1 A/B 95.7 145.0 C B/C 83.0 214.7
58 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
Figure 9.7 Predicted FDECs for each of the EFlow sites to achieve the target FDECs stipulated for Scenario 6
9.7 COMPARISON OF SCENARIOS AND INTERPRETATION OF RESULTS The 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.
59 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
Table 9.7 Scenario 2 Scenario Scenario Scenario 4 Estimated FDEC resulting Suggested 3 Scenario 5 Scenario 6 Sites 1: Muchinga non- Eastern Hydropower Amalgamation from the flow changes Current escarpment under each scenario negotiables Province 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 HS10 A A/B A A/B A/B 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 HS11 A A/B A A/B A/B A/B HS17 A A/B A A/B A/B A/B HS18 A A A A A A 9.1 A A/B A A/B A/B A/B HS12 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
60 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
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.
61 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
Table 9.8 Scenario 2 Scenario Scenario Scenario 4 Predicted overall Suggested 3 Scenario 5 Scenario 6 Sites 1: Muchinga non- Eastern Hydropower Amalgamation ecological condition Current escarpment (EC) resulting from the negotiables Province flow changes under each 2.1 B/C B/C B/C D B/C B/C scenario 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 HS10 B B/C B B/C B/C 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 HS11 B B/C B B/C B/C B/C HS17 B B/C B B/C B/C B/C HS18 B B B B B B 9.1 B B/C B B/C B/C B/C HS12 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
62 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
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.
63 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
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
64 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
The Basin Configuration Model provides a rapid indication of expected outcomes of possible basin development plans and can be 10. USING used to explore further scenarios of interest.
The model is under development: at the moment, new FDEC levels that THE BASIN 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 CONFIGURATION produced. This has been illustrated in this document for a range of new types and locations of dams. New areas of MODEL 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.
65 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
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
66 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
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. 11. 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 CONCLUSION 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.
67 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
• 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).
12.1 PREPARE FOR HAND OVER The EFlows Basin Configuration Model has 12. been pushed beyond its original format for this project.
An early part of Phase 2 should be to ensure it is RECOMMENDATIONS 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 ANALYSIS 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 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 MODELLING The assumptions made in developing this model for the Luangwa Basin are many and varied, and have been explained throughout the document.
68 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
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.
Goodwin P and G. Wright. 1998. Decision analysis for management judgement. John Wiley & Sons, Chichester, England. 13. 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. REFERENCES 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.
69 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows 70 70 70 54 54 62 54 62 62 82 82 96 82 96 96 48 48 Sep 75 57 75 57 75 57 64 64 50 50 64 50 44 44 88 88 88 Aug 51 51 51 45 45 45 58 58 58 68 68 68 40 40 80 80 80 Jul 61 76 76 52 52 70 54 45 45 42 58 58 66 66 48 40 80 Jun 61 77 41 77 47 67 67 52 52 59 59 54 69 46 46 40 80 May 41 41 47 47 47 79 53 53 78 53 78 69 68 68 60 60 60 Apr 71 71 61 41 47 55 55 54 63 63 42 49 69 49 82 82 80 Mar 61 73 73 70 54 56 56 42 83 43 83 64 50 64 50 48 80 Feb 41 41 47 47 47 79 53 53 78 53 78 69 68 68 60 60 60 Jan
77 77 72 53 53 56 63 83 49 43 46 46 68 68 40 60 60 Dec 71 71 71 97 55 97 55 97 55 62 62 62 82 82 82 48 48 Nov 72 72 72 56 63 56 63 56 63 49 49 84 98 84 98 84 98 Oct C C C B B B D D BC BC BC CD CD CD A/B A/B A/B FDEC 2.1 2.1 2.1 2.1 2.1 2.1 8.1 8.1 8.1 8.1 8.1 Site HS1 HS1 HS1 HS1 HS1 HS1 PERCENTAGES OF NATURAL FLOWS RECOMMENDED MONTHLY TO APPENDIX A. A HYDROLOGICAL SITES SITES EFLOWS THE 21 18 AND IN SUSTAIN SPECIFIED FLOW CONDITIONS (FDEC).
70 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows 70 70 54 70 62 54 62 54 62 82 82 96 96 82 48 96 48 48 48 Sep 75 57 75 57 75 57 64 50 64 50 44 64 44 50 44 44 88 88 88 Aug 51 51 51 45 45 58 45 58 58 68 68 40 68 40 40 40 80 80 80 Jul 67 76 55 55 52 59 78 70 78 70 62 62 46 42 42 48 40 40 48 Jun 77 41 79 55 79 55 53 70 63 70 63 46 42 49 42 49 68 40 60 May 71 71 61 41 41 81 81 47 79 54 56 56 49 69 64 43 49 64 43 Apr 51 51 74 74 72 56 63 42 45 49 58 43 82 58 66 66 84 84 44 Mar 57 75 75 73 67 67 52 65 59 52 59 85 45 43 85 45 50 44 84 Feb 71 71 61 41 41 81 81 47 79 54 56 56 49 69 64 43 49 64 43 Jan 71 71 41 47 53 78 63 56 63 56 49 43 49 43 68 40 60 80 80 Dec 71 71 71 97 55 97 55 97 55 62 62 62 82 82 82 48 48 48 48 Nov 72 72 72 56 63 56 63 56 63 49 49 49 49 84 98 84 98 84 98 Oct C C C B B B D D D D BC BC BC CD CD CD A/B A/B A/B FDEC 8.1 Site HS5 HS5 HS5 HS5 HS5 HS5 HS4 HS4 HS4 HS4 HS4 HS4 HS8 HS8 HS8 HS8 HS8 HS8
71 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows 61 81 47 70 54 62 70 54 54 62 82 96 69 96 82 48 96 96 48 Sep 75 57 75 57 74 56 64 50 49 43 64 64 44 50 44 88 88 88 88 Aug 51 51 51 67 45 58 45 45 39 58 58 68 68 40 40 80 80 80 80 Jul 79 55 79 55 55 70 78 62 78 70 42 62 62 42 42 69 48 48 48 Jun 79 79 55 70 63 56 70 78 78 42 62 54 49 62 42 42 69 48 48 May 71 71 81 81 81 81 72 56 56 63 56 64 43 50 49 43 49 43 64 Apr 51 74 57 57 73 73 65 65 83 58 66 83 50 44 82 50 82 44 44 Mar 51 51 75 74 74 67 52 59 45 45 58 58 66 84 66 84 44 84 84 Feb 71 71 79 55 79 63 56 56 63 70 63 49 43 49 42 43 49 80 80 Jan 71 71 71 63 56 56 63 63 56 49 43 49 43 49 43 80 80 80 80 Dec 71 71 81 97 55 97 97 55 97 70 62 54 62 82 62 82 48 48 48 Nov 71 72 72 55 63 56 63 56 63 49 83 49 84 98 98 48 84 98 98 Oct C C C B B B D D D BC BC BC CD CD CD A/B A/B A/B A/B FDEC 8.2 8.2 8.2 8.2 8.2 8.2 Site HS11 HS11 HS11 HS11 HS11 HS11 HS17 HS10 HS10 HS10 HS10 HS10 HS10
72 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows 70 70 54 70 62 54 62 54 62 82 82 82 96 96 48 82 96 48 48 Sep 75 57 75 57 75 57 75 64 64 50 50 64 50 44 44 44 88 88 88 Aug 51 51 51 45 78 45 58 45 58 58 68 66 68 68 40 40 40 80 80 Jul 77 41 55 47 55 78 70 53 78 62 62 42 42 69 48 69 48 68 60 Jun 61 41 67 76 78 53 54 78 62 54 42 69 69 46 48 69 48 40 60 May 71 71 55 76 56 56 63 70 62 49 43 64 49 42 43 48 68 80 80 Apr 57 57 73 74 73 72 65 65 56 83 50 49 50 43 64 82 44 44 84 Mar 51 51 74 57 74 74 73 45 58 58 66 83 66 64 44 50 66 84 44 Feb 71 77 41 81 55 47 72 70 53 63 56 63 42 49 49 43 68 60 80 Jan 71 71 55 76 63 56 56 70 63 62 49 43 49 43 42 48 68 80 80 Dec 71 71 71 55 97 55 97 55 62 62 62 82 82 83 82 48 48 48 98 Nov 72 72 72 56 63 56 63 56 63 49 49 49 84 84 98 84 98 98 84 Oct C C C B B B B D D D BC BC BC CD CD CD A/B A/B A/B FDEC 9.1 9.1 9.1 9.1 3.1 9.1 9.1 3.1 Site HS17 HS17 HS17 HS17 HS17 HS12 HS12 HS12 HS12 HS12 HS12
73 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows 41 57 79 67 79 67 70 70 54 54 62 93 62 93 82 96 48 48 48 Sep 57 75 57 59 70 59 70 36 64 64 50 50 43 82 44 50 82 44 88 Aug 71 71 51 51 51 31 57 37 39 45 58 50 43 44 68 40 60 60 80 Jul 61 41 47 55 73 73 78 78 78 62 54 56 42 69 64 48 84 48 84 Jun 61 74 74 55 79 79 78 53 62 54 42 45 42 69 48 48 68 68 60 May 61 41 81 81 47 55 76 76 70 63 54 70 70 54 42 62 49 46 80 Apr 51 57 81 81 73 76 76 65 70 45 70 58 54 62 83 66 50 46 44 Mar 51 81 81 74 76 76 52 59 70 45 70 54 62 58 46 66 46 84 40 Feb 72 55 72 56 70 63 56 63 63 42 43 49 64 42 50 49 68 68 80 Jan 41 47 55 79 67 76 53 76 70 62 42 83 58 83 50 48 89 89 60 Dec 71 72 55 97 55 97 97 63 59 70 70 62 49 82 43 82 50 82 48 Nov 72 72 56 63 56 59 63 70 70 49 49 43 82 96 50 82 84 96 98 Oct C C C B B B D D D BC BC BC BC CD CD CD A/B A/B A/B FDEC 3.1 3.1 3.1 3.1 4.1 4.1 4.1 4.1 4.1 4.1 4.2 4.2 4.2 Site HS2 HS2 HS2 HS2 HS2 HS2
74 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows 41 41 57 41 57 57 67 79 79 67 79 67 93 93 93 58 48 48 48 Sep 51 59 59 70 70 59 70 36 36 36 43 43 43 82 50 82 50 50 82 Aug 71 71 71 51 51 51 31 31 31 37 37 37 43 43 43 44 60 60 60 Jul 47 72 73 72 55 79 78 78 56 56 64 64 64 64 84 84 48 84 48 Jun 61 81 75 74 79 73 53 53 70 78 45 54 45 62 46 69 68 60 60 May 61 81 75 81 75 76 53 70 54 70 62 54 62 62 46 46 69 46 80 Apr 81 81 75 74 76 79 53 70 54 70 45 62 54 62 62 46 69 46 60 Mar 81 81 75 81 75 76 70 70 54 70 54 62 54 62 62 62 46 46 46 Feb 71 71 51 75 72 67 56 56 63 56 42 58 49 42 43 49 66 64 68 Jan 67 67 67 76 76 76 67 58 83 83 58 58 83 50 50 50 89 89 90 Dec 97 97 97 59 59 59 70 70 70 43 43 43 82 50 82 50 50 82 60 Nov 59 59 59 70 70 70 43 43 43 82 50 82 50 50 96 96 82 96 60 Oct C C C C B B B D D D BC BC BC CD CD CD A/B A/B A/B FDEC 5.1 5.1 5.1 5.1 5.1 5.1 4.2 4.2 4.2 Site HS7 HS7 HS7 HS7 HS3 HS3 HS3 HS3 HS3 HS3
75 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows 70 45 54 62 49 82 96 Sep 48 96 82 70 62 54 48 96 82 70 62 54 75 57 39 64 50 44 88 Aug 44 96 82 70 62 54 48 96 82 70 62 54 51 45 34 58 38 68 80 Jul 40 93 79 68 60 53 46 93 79 68 60 53 52 78 56 46 48 68 60 Jun 40 87 76 66 58 51 45 88 67 59 52 46 61 47 52 45 54 69 80 May 41 82 71 62 55 48 42 83 62 55 48 42 47 47 79 53 54 69 60 Apr 41 80 70 61 54 47 41 80 61 54 48 42 61 47 47 54 54 69 80 Mar 41 80 70 61 54 47 41 82 64 56 49 43 47 47 79 53 54 69 60 Feb 41 82 71 62 55 48 42 83 65 57 50 44 75 57 65 42 49 50 44 Jan 39 78 67 59 52 46 40 79 58 51 45 40 51 51 76 45 58 58 66 Dec 40 78 67 59 52 46 40 83 69 60 53 47 71 97 55 52 62 46 82 Nov 48 96 82 70 62 54 48 96 82 71 62 55 72 52 63 56 46 84 98 Oct 49 97 82 71 62 55 48 97 82 71 62 55 C B D BC CD CD A/B FDEC D A/B B BC C CD D A/B B BC C CD 10.1 10.1 10.1 Site 10.1 10.1 HS7 HS7 10.1 11.1 11.1 11.1 11.1 11.1 11.1 1.1 1.1 1.1 1.1 1.1
76 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows Sep 48 96 82 69 59 50 43 96 82 69 59 50 43 96 82 69 59 50 43 Aug 48 96 82 69 59 50 43 96 82 69 59 50 43 96 82 69 59 50 43 Jul 46 93 79 67 57 49 41 93 79 67 57 49 41 93 79 67 57 49 41 Jun 40 84 76 69 60 52 44 84 76 69 60 52 44 84 76 69 60 52 44 May 37 80 73 66 57 50 42 80 73 66 57 50 42 80 73 66 57 50 42 Apr 37 80 72 65 57 49 42 80 72 65 57 49 42 80 72 65 57 49 42 Mar 38 81 74 67 58 50 43 81 74 67 58 50 43 81 74 67 58 50 43 Feb 39 82 75 67 59 51 43 82 75 67 59 51 43 82 75 68 59 51 43 Jan 35 77 70 63 55 48 41 77 70 63 55 48 41 77 70 63 55 48 41 Dec 41 85 77 70 61 52 45 85 77 70 61 52 45 85 77 70 61 52 45 Nov 48 97 82 70 60 51 43 97 82 70 60 51 43 97 82 70 60 51 43 Oct 48 96 82 69 59 50 43 97 82 70 60 51 43 97 82 70 60 51 43 FDEC D A/B B BC C CD D A/B B BC C CD D A/B B BC C CD D Site 1.1 1.2 1.2 1.2 1.2 1.2 1.2 7.1 7.1 7.1 7.1 7.1 7.1 HS6 HS6 HS6 HS6 HS6 HS6
77 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows Sep 96 82 69 59 51 44 96 82 70 62 54 48 96 82 70 62 54 48 90 Aug 96 82 69 59 51 44 96 82 70 62 54 48 96 82 70 62 54 48 90 Jul 93 79 67 57 49 42 93 79 68 60 53 46 93 79 68 60 53 46 88 Jun 84 75 66 57 49 42 85 77 69 61 54 47 85 77 69 61 54 47 85 May 81 72 64 55 48 41 81 74 67 59 52 45 81 74 67 59 52 45 82 Apr 79 70 62 54 47 40 79 71 65 57 50 44 79 71 65 57 50 44 79 Mar 83 73 65 56 49 42 80 73 66 58 51 44 80 72 66 58 51 44 82 Feb 83 73 65 56 49 42 80 73 66 58 51 44 79 72 65 58 51 44 82 Jan 78 70 62 54 46 40 82 74 67 60 52 45 72 66 60 53 47 40 83 Dec 83 74 65 57 49 42 84 76 69 61 53 46 84 76 69 61 53 46 84 Nov 96 82 69 59 51 44 97 82 71 62 55 48 97 82 71 62 55 48 97 Oct 97 82 70 60 51 44 97 82 71 62 55 48 97 82 71 62 55 48 97 FDEC A/B B BC C CD D A/B B BC C CD D A/B B BC C CD D A/B Site 7.2 7.2 7.2 7.2 7.2 7.2 2.2 2.2 2.2 2.2 2.2 2.2 6.1 6.1 6.1 6.1 6.1 6.1 HS9
78 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows Sep 76 64 55 48 42 96 82 69 59 50 43 94 80 69 60 53 47 94 80 Aug 76 64 55 48 42 96 82 69 59 50 43 93 79 68 60 53 46 93 79 Jul 74 63 54 47 41 93 79 67 57 49 41 88 75 64 57 50 44 88 75 Jun 76 69 60 53 46 85 77 69 60 52 44 80 68 58 51 45 40 80 68 May 73 66 58 51 44 82 74 67 58 50 43 78 68 60 53 46 40 78 68 Apr 71 64 56 49 43 79 71 65 56 49 42 78 68 60 53 46 40 78 68 Mar 73 66 58 51 44 80 72 65 57 49 42 81 70 62 54 48 42 81 70 Feb 73 66 58 51 44 79 72 65 57 49 42 81 70 62 54 48 42 81 70 Jan 74 67 59 51 45 72 66 60 52 45 39 78 68 60 53 46 40 78 68 Dec 76 68 60 52 45 84 76 68 60 52 44 83 72 63 55 49 43 83 72 Nov 81 69 60 52 46 97 82 70 60 51 43 95 81 69 61 54 47 95 81 Oct 81 69 60 52 46 97 82 70 60 51 43 95 81 69 61 54 47 95 81 FDEC B BC C CD D A/B B BC C CD D A/B B BC C CD D A/B B Site HS9 HS9 HS9 HS9 HS9 HS18 HS18 HS18 HS18 HS18 HS18 12.1 12.1 12.1 12.1 12.1 12.1 12.2 12.2
79 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows Sep 69 60 53 47 94 80 69 59 53 48 94 80 69 60 53 47 94 80 69 Aug 68 60 53 46 93 79 68 58 53 47 93 79 68 60 53 46 88 75 64 Jul 64 57 50 44 88 75 64 55 50 45 88 75 64 57 50 44 81 69 59 Jun 58 51 45 40 88 78 69 60 54 47 80 68 58 51 45 40 80 68 58 May 60 53 46 41 86 76 68 59 52 46 75 66 58 51 45 39 78 70 62 Apr 60 53 46 41 80 71 63 55 49 43 79 69 61 54 47 41 82 73 65 Mar 62 54 48 42 76 68 61 53 47 42 82 71 63 55 49 43 83 73 66 Feb 62 54 48 42 81 72 65 56 50 44 82 71 63 55 49 43 83 74 66 Jan 60 53 46 41 71 64 57 50 44 39 79 69 61 54 47 41 81 72 65 Dec 63 56 49 43 91 81 72 62 56 49 83 73 64 56 50 43 80 71 64 Nov 69 61 54 47 95 81 69 60 54 48 95 81 69 61 54 47 95 81 69 Oct 69 61 54 47 94 80 69 59 53 48 95 81 69 61 54 47 95 81 69 FDEC BC C CD D A/B B BC C CD D A/B B BC C CD D A/B B BC Site 12.2 12.2 12.2 12.2 HS16 HS16 HS16 HS16 HS16 HS16 15.1 15.1 15.1 15.1 15.1 15.1 15.2 15.2 15.2
80 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows Sep 60 53 47 94 80 68 58 46 32 94 80 68 58 46 32 96 82 70 61 Aug 57 50 44 93 79 67 57 46 32 93 79 67 57 46 32 88 75 64 56 Jul 52 46 40 88 75 64 54 43 30 88 75 64 54 43 30 81 69 59 52 Jun 51 45 40 76 65 55 47 37 26 90 82 75 65 55 45 84 74 66 58 May 55 48 42 87 81 74 65 56 46 85 78 71 62 53 43 78 69 61 54 Apr 57 50 44 83 77 72 63 54 45 79 73 67 59 50 41 81 72 63 56 Mar 58 51 44 81 76 70 62 53 44 77 71 65 57 49 40 80 70 62 55 Feb 58 51 45 83 77 72 63 54 45 81 75 68 60 51 42 80 70 62 55 Jan 57 50 44 80 74 69 61 53 44 75 69 64 56 48 39 77 68 61 53 Dec 56 49 43 90 84 77 68 58 47 88 80 73 64 54 44 78 69 61 54 Nov 61 54 47 90 77 65 55 44 31 95 81 69 58 47 33 97 82 71 62 Oct 61 54 47 95 81 69 58 47 33 94 80 68 58 46 32 98 84 72 63 FDEC C CD D A/B B BC C CD D A/B B BC C CD D A/B B BC C Site 15.2 15.2 15.2 14.1 14.1 14.1 14.1 14.1 14.1 HS15 HS15 HS15 HS15 HS15 HS15 HS13 HS13 HS13 HS13
81 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows Sep 54 47 94 80 69 60 53 46 Aug 49 43 88 75 64 56 49 43 Jul 45 40 81 69 59 52 45 40 Jun 51 44 84 74 65 57 50 44 May 47 41 78 68 60 53 47 41 Apr 49 43 80 70 62 54 48 42 Mar 48 42 81 71 63 55 48 42 Feb 48 42 80 70 62 54 48 42 Jan 47 41 78 69 61 53 47 41 Dec 47 41 77 68 60 52 46 40 Nov 54 48 94 80 69 60 53 46 Oct 55 49 95 81 69 60 53 47 FDEC CD D A/B B BC C CD D Site HS13 HS13 HS14 HS14 HS14 HS14 HS14 HS14
82 Integrated Flow Assessment for the Luangwa River Zambia: Basin Configuration of Eflows
83
W W F
T E C HNI C A L
The Luangwa Basin R E P O
TOURISM R T
The South Luangwa National park generates 2 0
approximately 27,000,000 USD per year in 1 HYDROLOGY direct spending 8 The Luangwa River contributes approximately 28Km3 of flow to the Zambezi River upstream of Cabora Bassa Dam
CHALLENGES Why we are here If there is no URL WTaote stor avpai tlheab idliegrty ias deaxptionect eodf the planet’s natural environment and tot od ebcurildeas ae wfuittuhr eth ien c whiombcihn ehud mans live in harmony with nature. effects of climate change the
current rhythm and scale of W development W F . P Why we are here A To stop the degradation of the planet’s natural environment and For more information, Regular to build a future in which humans live in harmony with nature. contact: N D panda.org WWF-Zambia Country A . O
Angeles Boulevard, P.O. R
Box 50551 RW, Long acres, G Lusaka. ZAMBIA