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Governance and Economic Accounting Issues in the Mauritian Water Sector: toward Sustainable Management of a Natural Resource

Authors:

Abstract

Mauritius faces a problem of water shortages, especially at the end of the winter season, which is revealed by seasonal water accounts. A household survey shows that 43% of households adapt to those shortages using water tanks and pumps. The study forecasts an increase in water demand of up to 51% by 2030 leading to a water shortage of up to 52 million m3 taking the effects of climate change into account. After analyzing different options, it seems that improvements in the water sector necessitates restructuring tariffs in different sectors with new roles of institutions in raising revenues. Current water sector governance, however, seems ineffective to solve these issues. The micro-institutional setting according to the distribution of tasks for each of the main transactions reveals a multitude of water actors at the national level. Responses from these water actors collected for this study point to a certain number of challenges putting sustainability at stake, including a lack of political commitment and discontinuity of reforms. These issues seem to be aggravated by a lack of independence of the main water agencies. The study concludes with policy recommendations to increase efficiency of the water sector.
NATURAL RESOURCE MANAGEMENT NATURAL WEALTH
ACCOUNTING*
GOVERNANCE AND ECONOMIC ACCOUNTING ISSUES IN THE
MAURITIAN WATER SECTOR: TOWARD SUSTAINABLE
MANAGEMENT OF A NATURAL RESOURCE
Peeroo, A.**, and Sultan, R.***
JEL Classification: H11; H54; L95; L98; Q25; Q56; R22
Keywords: water accounting; water supply and demand, economic value of water;
sustainability; micro-institutions; water sector governance; water sector reform;
decentralization
*“Natural Resource Management Natural Wealth Accounting“ is a capacity building
program launched by the Global Development Network (GDN) in 2014 to help three
ecologically fragile countriesMadagascar, Mauritius and Moroccoto understand the
interactions between natural resources and socio-economic activities. The program is
supported by the French Ministry of Foreign Affairs and International Development and the
French Agency for Development (AFD).
** Chief Consultant (InfraGovernance Consulting) and Senior Research Fellow at Delft
University of Technology. Contact: ap@infragovernance.com
***Senior Lecturer at the University of Mauritius, Department of Economics and Statistics.
Contact: r.sultan@uom.ac.mu
2
Acknowledgments
We are grateful to the Global Development Network for its financial support and expertise,
especially to Pierre Bertrand, Mansoor Ali Sait and Yashika Kanojia, who have accompanied
this project all along. We extend our thanks to Prof. Bernard Barraqué, our scientific advisor.
His comments and suggestions have always been helpful and extremely valuable as have
been the numerous examples he has provided through his expertise and field experience.
We would also like to thank the participants of the three GDN workshops for their input, and
especially Jean-Louis Weber and Dr. Yann Laurans whose comments were very insightful and
helped a lot in the early stages of the project. A special thanks and recognition goes to
Ricardo Martinez-Lagunes for his valuable advice and for sharing his previous work on water
accounts in Mauritius. In addition, we would like to thank Anand Sookun, our project
assistant, who provided valuable input to the water accounts and all the statistics.
Furthermore, our thanks go to the Charles Telfair Institute and its team, especially Vikash
Rowtho, for hosting and organizing our workshop on water sector governance and the
subsequent dissemination workshop. We would like to thank our student helpers: Suneil
Boojhawon who did the layout for our policy briefs and Remena Mootien and Hanan Peerun
who assisted with the dissemination workshop. Finally, we would like to thank David
McDevitt who has done a great job editing our work.
Research discussed in this publication has been supported by the Global Development
Network (GDN). The views expressed in this report are not necessarily those of GDN.
3
Table of Contents
List of Tables ............................................................................................................................ 5
List of Figures ........................................................................................................................... 6
List of Abbreviations ................................................................................................................ 7
Abstract……………………………………………………………………………………………………………………………..8
Chapter 1: Introduction ........................................................................................................... 8
1.1 Water Situation in Mauritius ................................................................................... 9
1.2 Sustainability and Water Sector Governance ........................................................ 10
1.3 The Case for Water Accounts to Improve Decision Making and Governance ...... 11
1.4 Objectives of the Study .......................................................................................... 11
1.5 Roadmap ................................................................................................................ 12
References ........................................................................................................................... 14
SECTION 1: WATER ACCOUNTS, TRENDS IN WATER USE, AND ECONOMIC VALUE OF
WATER IN MAURITIUS .................................................................................................... 15
Chapter 2: Water Accounting in Mauritius ............................................................................ 16
Introduction ......................................................................................................................... 16
2.1 Water Accounting Systems: A Brief Review of the Literature ............................... 17
2.2 Water Accounting: Conceptual Framework .......................................................... 18
2.3 Water Accounts for Mauritius: Empirical Evidence ............................................... 21
2.4 Water Asset Accounts ............................................................................................ 23
2.5 Water Balance ........................................................................................................ 23
2.7 Total Water Abstraction: Sources and Users ......................................................... 27
2.8 Water Abstracted by the Water Supply Industry .................................................. 28
2.9 Physical Flow Account of Water: Supply and Use Table ........................................ 31
2.10 Water Abstraction at Regional and Seasonal Levels ............................................. 35
2.11 Seasonal Water Accounts ...................................................................................... 37
References ........................................................................................................................... 42
Chapter 3: Trends in Water Use, Economic Value of Water, and a Scenario-based
Analysis of Water Demand and Supply for 2030 ................................................................... 44
Introduction ......................................................................................................................... 44
3.1 Water as an Economic Good .................................................................................. 45
3.2 Water Utilization in Mauritius ............................................................................... 46
3.3 Modeling Residential Water Consumption............................................................ 48
3.4 Modeling the Demand for the non-Residential Sector: Marginal Productivity of
Water ………………………………………………………………………………………………………………………..…52
3.5 Scenario-based Analysis of Water Use and Water Abstraction............................. 55
3.6 Water Abstraction Under Climate Change Scenarios ............................................ 59
3.7. Behavior of Households Toward Water Shortages: Evidence From the Water Use
Survey 61
Conclusion ........................................................................................................................... 64
References ........................................................................................................................... 65
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SECTION TWO: WATER GOVERNANCE ............................................................................. 67
Chapter 4: The Institutional Setting of Mauritian Water Sector Governance: What
Place for Sustainability? ......................................................................................................... 68
Introduction ......................................................................................................................... 68
4.1 The Nature of Water Sector Governance .............................................................. 69
4.2 A Framework for the Analysis of Water Sector Governance ................................. 72
4.3 Mauritian Actors for Water Sector Governance and Their Sustainability
Considerations ..................................................................................................................... 73
4.4 The Micro-institutional Set-up for Mauritian Water Sector Governance ............. 82
4.5 Conclusion .............................................................................................................. 86
References ........................................................................................................................... 88
Chapter 5: Governance Issues in the Mauritian Water Sector Impeding Sustainability ....... 91
Introduction ......................................................................................................................... 91
5.1 Data ........................................................................................................................ 92
5.2 Governance Issues in the Mauritian Water Sector ................................................ 93
5.3 Findings from the Analysis of Water Governance in Mauritius ............................. 98
5.4 Quo Vadis? ........................................................................................................... 100
References ......................................................................................................................... 102
SECTION THREE: POLICY IMPLICATIONS .......................................................................... 104
Chapter 6: Summary of Key Findings and Policy Recommendations .................................. 105
Introduction ....................................................................................................................... 105
6.1 Water Accounts .................................................................................................... 105
6.2 Price, Income and Output Elasticity of Water ..................................................... 106
6.3 Household Survey on Water Use ......................................................................... 106
6.4 Economic Value of Water .................................................................................... 107
6.5 Forecast of Demand for Water and Climate Change Scenarios .......................... 107
6.6 Ensuring the Sustainable Supply of Water: Policy Implications .......................... 108
6.7 The Institutional Setting of Water Sector Governance ....................................... 109
6.8 Water Sector Governance and (the Lack of) Sustainability ................................. 110
6.9 Policy Recommendations to Improve Water Sector Governance ....................... 111
References ......................................................................................................................... 114
Annexes ................................................................................................................................ 115
Annex A: Water Legislation in Mauritius ........................................................................... 115
Annex B: Water Governance Survey ................................................................................. 124
5
List of Tables
Table 1: Basic Statistics for Mauritius for 2013 ........................................................................ 22
Table 2: Water Balance, 2009 to 2013 (million m³) ................................................................. 24
Table 3: Water Balance in Mauritius, 2013 (million m³) .......................................................... 26
Table 4: Sources of Total Water Abstraction, 2008-2013 (million m³) .................................... 27
Table 5: Water Abstraction Account, 2013 .............................................................................. 28
Table 6: Storage Capacity of Reservoirs in Mauritius .............................................................. 28
Table 7: Water Sources by Regions .......................................................................................... 29
Table 8: Minimum and Maximum Water Levels in Mauritius ................................................. 30
Table 9: Water Abstraction by Water Supply Industry, 2003-2013 (million m³) ..................... 30
Table 10: Water Account for the Water Supply Industry, 2013 (million m³) ........................... 31
Table 11: Supply Table for Water, 2013 ................................................................................... 32
Table 12: Use Table for Water, 2013 ....................................................................................... 34
Table 13: Estimates of Water Requirements and Water Production on a Monthly Basis ....... 35
Table 14: Seasonal Water Balance, 2013 (million m³) ............................................................. 37
Table 15: Total Water Abstraction on Seasonal Basis, 2013 (million m³) ................................ 38
Table 16: Water Abstraction by Water Supply Industry on a Seasonal Basis, 2013 (million
m³) ............................................................................................................................................ 38
Table 17: Supply and Use Table for Summer Season, 2013 ..................................................... 39
Table 18: Supply and Use Table for Winter Season, 2013 ....................................................... 40
Table 19: Water Consumption in Mauritius, 2013 ................................................................... 47
Table 20: Domestic Monthly Tarrif for Potable Water, 2013 .................................................. 48
Table 21: Non-Domestic Monthly Tarrifs for Potable Water, 2014 ......................................... 48
Table 22: Unit Root Test of Variables ....................................................................................... 50
Table 23: Results for Demand for Water for Residential Purposes ......................................... 51
Table 24: Long-run Demand Function for Water in Mauritius ................................................ 51
Table 25: Regression Analysis of the Marginal Value of Water ............................................... 54
Table 26: Trans-log Production Function ................................................................................. 55
Table 27: Error Correction Model for Domestic Water Consumption ..................................... 56
Table 28: Error Correction Mode for non-Domestic Water Consumption .............................. 57
Table 29: Residential and non-Residential Demand for Water in 2030 .................................. 58
Table 30: Climate Change Scenarios for Rainfall by 2030 (A2, A1B and B1)............................ 60
Table 31: Indicators on Water from the Survey ....................................................................... 62
Table 32: Ratio of Water Bill to Monthly Household Income .................................................. 62
Table 33: Relationship between Share of Water Bill, Household Income and Household
Size ............................................................................................................................................ 63
Table 34: Logit Regression Water Tank and Household Income .......................................... 64
Table 35: Micro-Institutional Setting for Water Sector Governance in Mauritius .................. 83
6
List of Figures
Figure 1: Physical Water Flows within the Economy ............................................................... 20
Figure 2: Total Rainfall in Mauritius, 2000 - 2013 (million m³) ................................................ 24
Figure 3. Distribution of rainfall in Mauritius in 2013 .............................................................. 25
Figure 4: Water Abstraction in Mauritius, 2000 to 2012 (million m³) ..................................... 27
Figure 5: Production of Potable Water Versus Water Demand, Northern Region .................. 36
Figure 6: Production of Potable Water Versus Water Demand, Southern Region .................. 36
Figure 7: Production of Potable Water Versus Water Demand, Central Region ..................... 37
Figure 8: Demand for Water Consumption in the Residential Sector ..................................... 50
Figure 9: Consumer Surplus in Mauritius ................................................................................. 52
Figure 10: Forecast of Demand for Residential Water, 2016-2030 ......................................... 57
Figure 11: Forecast of Demand in the non-Residential and Government Sectors, 2015-
2030 .......................................................................................................................................... 58
Figure 12: Aggregate Demand for Water in 2030 Under Different Economic Growth
Scenarios .................................................................................................................................. 59
Figure 13: Total Water Production Under Climate Change Scenarios in 2030 (millions m³) .. 60
Figure 14: Water Shortages Under Different Climate Change and Economic Growth
Scenarios (millions m³) ............................................................................................................. 61
Figure 15: Ratio of Water Bill to Monthly Household Income ................................................. 63
7
List of Abbreviations
ARDL Autoregressive Distribution Lag
CWA Central Water Authority
ECM Error Correction Model
GDN Global Development Network
GPWA General Purpose Water Accounting
IOC Indian Ocean Commission
MEPU Ministry of Energy and Public Utilities
MUR Mauritius Rupee
PSUT Physical Supply and Use Table
SEEA-Water System of Environmental-Economic Accounting for Water
WFA Water Footprint Accounting
WMA Wastewater Management Authority
WRU Water Resources Unit
8
Abstract
Mauritius faces a problem of water shortages, especially at the end of the winter season,
which is revealed by seasonal water accounts. A household survey shows that 43% of
households adapt to those shortages using water tanks and pumps. The study forecasts an
increase in water demand of up to 51% by 2030 leading to a water shortage of up to 52
million m3 taking the effects of climate change into account. After analyzing different
options, it seems that improvements in the water sector necessitates restructuring tariffs in
different sectors with new roles of institutions in raising revenues. Current water sector
governance, however, seems ineffective to solve these issues. The micro-institutional setting
according to the distribution of tasks for each of the main transactions reveals a multitude of
water actors at the national level. Responses from these water actors collected for this study
point to a certain number of challenges putting sustainability at stake, including a lack of
political commitment and discontinuity of reforms. These issues seem to be aggravated by a
lack of independence of the main water agencies. The study concludes with policy
recommendations to increase efficiency of the water sector.
9
Chapter 1: Introduction
Aleksandra Peeroo and Riad Sultan
1.1 Water Situation in Mauritius
Water is a vital natural resource for human activities and survival generally. While it may be
abundant on a regional scale, only a small portion is typically usable, making it a de facto
scarce resource. Of the total global water demand, 11 percent comes from households, 19
percent from industry (including energy production), with the bulk, 70 percent, coming from
agriculture (Food and Agriculture Organization, 2012). Because of population growth and
related increases in the demand for food and energy, it is expected that water demand will
rise further in the future, putting more pressure on water resources.
These constraints on water resources are exacerbated by climate change. Among other
impacts, rising sea levels risk contaminating freshwater supplies, and droughts and floods
are becoming more frequent and more severe (International Environment Agency, 2012).
Over-usage of water poses important threats. This is illustrated by the example of Mexico
City, where the depletion of the underground aquifer has resulted in the city sinking by
several meters, causing negative externalities like damage to buildings, roads, pipes and
other infrastructure (Haggarty et al., 2002). In addition, competition for water provision
between different consumer groups leads to conflict and may even cause social unrest
(Ménard and Peeroo, 2011). Therefore, the sustainability of water is becoming a major
policy issue for decision-makers.
In small island states, such as Mauritius, sustainability of the provision of water is an urgent
issue for relevant stakeholdersincluding the various consumer groups, civil society groups,
policymakers and the water supply industry. In 2013, Mauritius received 3,821 million cubic
meters of rainfall of which 70 percent was available for exploitation through surface runoff
(2,293 million m3) and groundwater (382 million m3). The remaining 30 percent (1,146
million m3) cannot be used for water production because it is lost to evapotranspiration.
Furthermore, given the topography of Mauritius, a large proportion of the surface water
runoff flows directly into the sea. For this reason, only 8 percent of available water was
abstracted by the water supply industry for distribution to households, industry, government
agencies and agriculture in 2013.
At first sight, it appears that there is no apparent water scarcity in Mauritius. However, two
major issues pose a threat to the availability of drinking water. Firstly, there is a significant
difference between the wet and dry seasons. Water reservoirs may be depleted by the end
of the latter. Secondly, the production of drinking water by the national provider, the Central
10
Water Authority, involves a very high percentage of Non-Revenue Water,1 amounting to
around 55 percent (National Economic and Social Council, 2014, pp. 14 f.). Physical losses
through leaky pipelines account for 35-40 percent of produced drinking water. Another 10-
15 percent are commercial losses due to defective meters, illegal connections, etc. The
remainder are explained by authorized unbilled consumption for example, for fire fighting.
Together, the amount of water lost correponds to about four times the capacity of the
largest reservoir on the island. This water wastage has been going on for decades. Given the
high percentage of Non-Revenue Water, it is, therefore, not surprising that the supply of
water scarcely meets the demand. As a consequence, some regions in Mauritius do not have
access to potable water on a 24/7 basis.
1.2 Sustainability and Water Sector Governance
The current water situation in Mauritius urgently calls for sustainability considerations to be
taken into account. Three facets of sustainability must be ensured with regard to water
resources, and drinking water and wastewater services: economic, environmental and social.
In this respect, effective water sector governance is vitally important for water (resource)
management.2 Problems in the governance of the water sector understood as the system
in place to oversee, plan, direct, monitor and enforce transactions between the various
water uses lead to dysfunctions that may become apparent in indicators of low
performance, such as high leakage rates. In addition, sectoral characteristics, such as the
natural decentralization of the water sector, usually influence the governance of the water
sector (Peeroo, 2014, pp. 23 ff.). Decentralization is explained by two reasons. Firstly, water
is physically heavy, one liter of water weighing one kilogram. This makes it difficult and
costly to transport over long distances. As a consequence, water resources management is
typically local or regional. Secondly, water utilities themselves are usually local. Therefore,
local and regional actors play a natural role in the governance of the water sector (Ménard
and Peeroo, 2011). A coherent system of water sector governance requires a clear
distribution of tasks and responsibilities across various water actors. In order to direct
policies toward the consideration of sustainability issues, the governance of the sector needs
to be well understood so that institutional dysfunctions can be addressed (Peeroo, 2014, pp.
79, 158). The role of information is critical. Information must be relevant, standardized and
coherent in order to provide a basis for good decision-making (ibid., p. 166).
1 Non-Revenue Water measures the percentage of water that has been produced but which has not
generated any revenue.
2 The Mauritian water sector involves water policy and politics with a specific set of actions and
actors, separated from other public policies. Within the water sectors of high-income countries, two
different sub-sectors can often be distinguished: one relating to water resources and the other to
water services (both drinking and wastewater). In Mauritius, however, as in many developing
countries, there are no such sub-sectors: the water sector consists only of one set of actors, although
diversified and multiple. Formally, a specific Water Resource Unit exists, but it does not hold enough
decision-making power to constitute a distinct sub-sector for water resources with independent
actors and policies that are separated from the actors and policies concerning water services. We are
grateful to Bernard Barraqué who pointed out this difference between the water sectors of
developed and developing countries.
11
1.3 The Case for Water Accounts to Improve Decision Making and
Governance
Information plays a crucial role in decision-making. In order to manage water sustainably,
there is a need to organize information on water including water storage, water
distribution, and water usein a relevant, standardized and coherent manner (Peeroo,
2014, p. 166). Natural resource accounting in the water sector provides information on the
present state of water management in terms of its current use and economic contributions.
It also assists in identifying future water uses and water management policies. Furthermore,
it helps gain an understanding of how different policies will impact on water demand and
informs on potential trade-offs. It also permits the conceptualization of the economic value
of water. Consequently, the impact of droughts, climate change and any negative
externalities on the water sector can be analyzed in terms of changes in the total volume, as
well as changes in the natural wealth. A complete water account is useful to better manage
water as a natural resource and to design instruments to ensure the sustainability of the
water sector.
At the same time, water accounts may increase the informational basis for decision-making
and, in turn, policymaking. However, the successful implementation of policies will depend
on the governance and institutional setting. The economics of water indicates some ways to
achieve efficient water management. Infrastructural weaknesses may require specific
investment decisions, but institutional and governance issues may prevent a review of the
tariff structure and thereby the necessary investments.
Therefore, an analysis of the governance issues in the Mauritian water sector is important in
response to some of the questions that are raised from an analysis of supply and demand. A
lack of effective water sector governance explains why it is so difficult to remedy a system
which is not responding to the requirements of the population. The study of water
governance issues also illustrates how (in)effective the system is in designing policies and
strategies for the sector. In this respect, governance and economic accounting of water in
Mauritius will play an important role in addressing the water crisis which the island is facing.
1.4 Objectives of the Study
The aim of the study is to conduct an assessment of governance issues in the context of a
need for sustainable water services and to construct a water account system, together with
an analysis of the economic contribution of water for the small island state of Mauritius.
The objectives of the study are:
To make an assessment of the current water situation in Mauritius
To conceptualize the physical use and supply of water in the Mauritian context and
construct the economy-water linkages and a water account based on the system of
Environmental-Economic Water Accounting for Water (SEEA-Water)
To study the demand for water in different sectors (agriculture, industry, energy,
tourism and households) and its economic value to the economy
12
To provide a scenario-based analysis of the impacts of climate change and changing
trends of water use
To draw a picture of the micro-institutional setting that governs the Mauritian water
sector (actors with their respective responsibilities and levels of intervention)
To critically analyse governance issues in the Mauritian water sector and its political
economy
To analyze the link between governance and sustainability considerations
To design policy recommendations for sustainable water use and efficient water
sector governance
1.5 Roadmap
Our study is structured in three sections. Section one (Chapters 1 and 2) are dedicated to
questions related to the water accounts for Mauritius. The current trends of water demand
are analyzed and data and information are collected to construct water accounts for the
country. This offers insights on key indicators including price and income elasticities for the
household sector, and output elasticity and marginal productivity of water in various
economic sectors of Mauritius, which might prove helpful for policymaking. A survey on the
water use by households has also been conducted, the results of which are provided in sub-
section 3.7 of this study3. Furthermore, because sustainable water policies depend on future
trends of water abstraction and water use, Chapter 3 forecasts water consumption for the
non-residential and residential sectors in Mauritius for 2015 to 2030, taking into account
different scenarios of how climate change and economic growth might impact on water
demand.
Section two (Chapters 4 and 5) focuses on Mauritian water sector governance. Chapter 4
elaborates on the nature of water sector governance in general, and the issue of
sustainability. It also provides a theoretical framework for the analysis of water sector
governance, which is then applied to the case of Mauritius. Using an original dataset, the
framework identifies the various water governance actors and their respective
responsibilities. The objectives of Chapter 4 are thus twofold: firstly, to develop an
institutional map for water sector governance in Mauritius and secondly, to analyse the
extent to which the various water actors take sustainability considerations into account.
Chapter 5 is centered around a number of specific governance issues in the Mauritian water
sector that have been highlighted by a survey that was conducted as part of the research. It
appears that the main impediments to a more sustainable water sector are linked to
weaknesses in governancea lack of coordination of the multitude of water actors in an
institutional environment with little transparency.
Chapter 6 sums up the major findings emanating from the previous chapters and provides
policy implications for improving the sustainability of water supply in Mauritius. More
specifically, it highlights some aspects of Mauritian water sector governance that endanger
3 The reader should contact Riad Sultan (r.sultan@uom.ac.mu) to btain further information on this
survey.
13
the sustainability of water and proposes a number of concrete policy measures that could be
adopted to improve water sector governance.
14
References
Food and Agriculture Organization (2012). United Nations Food and Agriculture
Organization. Aquastat Database,www.fao.org/nr/water/aquastat/main/index.stm
(30.09.2014).
Haggarty, L., Brook, P., and Zuluaga, A. M. (2002). Water Sector Service Contracts in
Mexico City, Mexico. In: Shirley, M. M. (ed.), Thirsting for Efficiency: The Economics and
Politics of Urban Water System Reform, pp. 139-187. Amsterdam and others: The World
Bank.
International Environment Agency (2012). Water for Energy: Is Energy Becoming a Thirstier
Resource? Excerpt from the World Energy Outlook 2012. Paris: International Energy
Agency IEA online.
Ménard, C. and Peeroo, A. (2011). Liberalization in the Water Sector: Three Leading
Models. In: Finger, M. and Künneke, R. W. (eds.), International Handbook of Network
Industries: The Liberalization of Infrastructure, pp. 310-327. Cheltenham and others:
Edward Elgar Publishing.
National Economic and Social Council. (2014). Management of Water Resources. NESC
Report No. 28.
Peeroo, A. (2014). Decentralization and the Water Sector: Institutional Perspectives. PhD,
University of Paris 1 Panthéon-Sorbonne.
15
SECTION 1: WATER ACCOUNTS, TRENDS IN WATER USE, AND
ECONOMIC VALUE OF WATER IN MAURITIUS
16
Chapter 2: Water Accounting in Mauritius
Riad Sultan
Introduction
The United Nations report, Water for a Sustainable World(WWAP 2015), observes that
over-abstraction of water is often the result of out-dated models of natural resource use. A
sustainable water management system, therefore, calls for an efficient mechanism to
organise information on water in the economy, in a relevant, reliable, understandable,
comparable and timely manner (Molden, 1997; Molden and Sakthivadivel, 1999; Burrell et
al., 2012; Chalmers et al., 2012). Water accounting has been a response to the lack of
organised data in the water sector. It is a method of organising and presenting information
relating to the physical volumes of water in the environment and economy, and the impacts
of human activities on water resources (Vardon et al., 2007) and allows us to model the
potential impacts of different policies in the water sector. It can be used to integrate the
economic aspects of water supply and use. Moreover, managers in the water sector are
facing greater demand for transparency with defined lines of responsibility and
accountability. Therefore, a systematic means to record and report diverse data relating to
water is becoming a necessity. Many countries are already preparing water accounts on a
regular basis, while others have started their water accounts on a pilot basis (Lange and
Hassan, 2006).
Following the pioneering work of the World Resources Institute (Repetto et al., 1989; Lange,
2007), water accounting is becoming increasingly popular in the analysis and design of
sustainable development strategies. It aims at providing answers on how water is currently
being used, the economic contribution of water use at a sectoral level, the opportunity cost
of water use for each economic sector and whether the present use of water represents its
best use (Lange, 1997). It may be further used to shed light on future water uses, with due
consideration of the water demand by different sectors, and examine how policies may
affect the demand for water to meet development objectives. Water accounting can help
analyze economic trade-offs more easily and establish priorities (Lange, 1997).
This section of the study aims to construct water accounts for the small island economy of
Mauritius, by analyzing the physical stock and flow of water, the utilization of water in
different sectors and the supply of water from various sources (surface and ground). Water
accounts are prepared for the year 2013, as well as on a seasonal basis to differentiate
between summer and winter, using the System of Environmental-Economic Accounting for
Water (SEEA-Water) guidelines.
This chapter is structured as follows: Section 2.1 provides a brief literature review on water
accounting, followed by a description of the conceptual framework in Section 2.2. Reference
is made to SEEA-Water, a document on the design of water accounts, published by the
United Nations Statistics Division in 2007 (UN, 2012). Section 2.3 provides an overview of the
water sector in Mauritius, together with water accounts for the country. Sections 2.4 to 2.11
17
provide the findings of the water accounts explicitly classified as water asset accounts;
water balance; total water abstraction; water abstracted by the water supply industry;
physical flow acount of water; water abstraction at regional and seasonal levels; and
seasonal accounts.
2.1 Water Accounting Systems: A Brief Review of the Literature
It is increasingly recognized that for the effective management of a resource such as water, a
systematic approach is needed to report information in a transparent manner. Water
accounting enhances our understanding of the link between the water cycle and human
activity, and provides a tool for improved management of water (Lange and Hassan, 2006).
However, water accounting systems have different origins. According to Chalmers et al.
(2012), water account systems can be regarded as a response to a social and institutional
practice designed for intervening in the functioning of a sector. Over the years, several water
accounting systems have been developed, such as the General Purpose Water Accounting
(GPWA), the System of Environmental-Economic Accounting for Water (SEEA-Water), Water
Footprint Accounting and a system implemented by the International Water Management
Institute (IWMI WA).
The GPWA reports include a Statement of Physical Flows, a Statement of Water Assets and
Water Liabilities, and a Statement of Changes in Water Assets and Water Liabilities (Burrell
et al., 2012). The Statement of Physical Flows shows how holdings of water evolved during
the reporting period. In the Statement of Water Assets and Water Liabilities, the assets
component contains an overview of the water rights and other entitlements to water, while
the liabilities component reports obligations to provide water or water rights (Chalmers et
al., 2012). The Statement of Changes in Water Assets and Water Liabilities shows
movements in water assets and water liabilities during the reporting period. According to
Chalmers et al. (2012), the GPWA is more an assessment of accountability for water
management and the consequent allocation of economic, environmental or social resources.
It is primarily designed for stakeholders as a tool to facilitate decision-making on the
allocation of resources.
The SEEA-Water was developed by the United Nations Statistics Division, in collaboration
with the London Group on Environmental Accounting. This system is a conceptual
framework for the organization of both physical and economic information related to water
using concepts, definitions and classifications, consistent with those of the System of
National Accounts 2008.4 The SEEA-Water is an extension of the United Nations System of
Environmental-Economic Accounting, recording information on environmental and related
socioeconomic indicators in a manner similar to the way in which many countries’ national
accounts record information about economic transactions. SEEA-Water accounting includes
a physical supply and use table, showing flows of water from the environment to the
economy and the movement of water within the economy. It also includes a water emissions
4 The System of National Accounts 2008 was adopted by the UN Statistical Division as the
international standard for compilation of national accounts statistics and for the international
reporting of comparable national accounting data.
18
account. Asset accounts record water stocks in physical terms (the volumes of water) and
report their amounts at the beginning and end of a period, as well as the changes during a
reporting period. According to Chalmers et al. (2012), SEEA-Water is based on the
information needs of an assumed audience of policy analysts and informed researchers; as
opposed to a general-purpose approach, which provides information for use by
policymakers or stakeholders.
IWMI WA provides information on the supply and use of water and relates water use to the
economy (Molden, 1997; Chalmers et al., 2012). It is a multi-scale method to account for the
amount of water available, the amount of water used by various sectors and the value
derived from water use. It is based on a water balance approach, which translates water
balance components, and inflows and outflows into various water accounting categories
such as net inflow, process consumption, non-process depletions, committed outflow and
uncommitted outflow. One major difference between the IWMI WA and other accounting
frameworks is the use of water consumption as opposed to water withdrawals. Accordingly,
this approach helps to track water reuse as it accounts for consumed water rather than
diverted flow to a particular domain. However, it does not show water withdrawals and the
efficiency of water use (Karimi et al., 2012).
Many countries including China (Zhu et al., 2009), Australia (Chalmar et al., 2012; Turner et
al., 2014), Botswana, Namibia and South Africa (Lange et al., 2006) have developed water
accounts on a regular basis. Water accounts have been used to analyze issues such as
poverty, economic growth and international trade, among others. Gao et al. (2013) use a
water accounting model in Beijing to analyze development patterns and water consumption.
Their study makes use of the input-output model. Biltonen and Dalton (2003), designed a
framework which links water accounting to poverty. Lange and Hassan (2006), extend the
water account systems prepared in Lange et al. (2006) to examine the link between
international trade and water use in three countries: Botswana, Namibia and South Africa.
Physical and monetary accounts of water can be used to analyse a wide range of issues
pertaining to water, including the constraints on water posed by the possible effects of
climate change, the role of water pricing and conflict management among users.
Consequently, they may also be used to analyze policies which maximize the wealth or
economic efficiency of water as a natural resource, with due consideration of equity in, and
sustainability of, the water sector.
2.2 Water Accounting: Conceptual Framework
Water accounting forms part of the National Resources Accounting detailed in the
Integrated Environmental and Economic Accounting Handbook (UN, 2003). Since water
requires specific treatment, the United Nations Statistical Division published the System of
Economic-Environmental Accounting for Water (SEEA-Water) in 2007. The SEEA-Water
19
provides a framework to analyse the role of water in the economy through a system of
satellite accounts linked to national accounts.5
Water accounting, according to SEEA-Water, is separated into water asset (or stock)
accounts and water flow accounts (UN, 2012):
1. Asset accounts measure the stocks at the beginning and at the end of the accounting
period and, record the changes in stocks that occur in between. There are two types of
water assets, ‘produced assets’ and ‘water resources’:
a. Produced assets include the infrastructure to abstract, distribute, treat and
discharge water.
b. Water resources describe the volume of water resources in the various asset
categories at the beginning and the end of the accounting period and all the
changes therein that are due to natural causes (precipitation, evapotranspiration,
inflows, outflows) and human activities. In addition, quality accounts record
stocks of water in terms of its quality.
2. Water flow accounts record the volume of water that passes from the environment into
national economies. More specifically, they record the volume of water supplied by an
economic agent either for its own use or for delivery to another use. It also records the
volume used by both economic and domestic sectors (Arntzen et al., 2010).
Figure 1, reproduced from the SEEA-Water document (UN, 2012), describes physical water
flows within the economy. Water flow is divided into three components: (i) the flow of water
from the environment to the economy; (ii) flows of water within the economy and between
economies; and (iii) flows from the economy to the environment.
5 As satellite accounts of the System of National Accounts, SEEA-Water is linked to a full range of
economic activities with a comprehensive classification of environmental resources.
20
Figure 1: Physical Water Flows within the Economy
Source: SEEA-Water (UN, 2012)
Water supply and use tables are used to record components of theinland water system
which includes surface water (rivers, lakes and artificial reservoirs), groundwater and soil
water, within the territory of reference. All flows associated with the inland water system
are recorded in the asset accounts for water resources, including flows to and from
accessible seas and oceans.
According to SEEA-Water, physical supply and use tables can be compiled at various levels of
detail, depending on the required policy and analytical focus, and data availability. A basic
supply and use table for water is divided into five sections as follows:
1. Abstraction of water from the environment
2. Distribution and use of abstracted water across enterprises and households
3. Flows of wastewater and reused water (between households and enterprises)
4. Return flows of water to the environment
5. Evaporation, transpiration and water incorporated into products
The aim of physical flow accounting is to record the physical flows underpinning monetary
transactions, primarily with respect to goods, and then to extend the supply and use tables
to record physical flows from the environment to the economy (such as natural resources)
and physical flows from the economy to the environment (such as emissions into air and
water).
A specific terminology is used with regard to water accounts. The common definitions are as
follows:
21
Available water: Available water is defined as the availability of internal renewable
water resources. This gives an indication of the amount of water that is internally
made available through precipitation (minus evapotranspiration, i.e. efficient
precipitation). These resources are computed by adding up the volume of the
average annual surface runoff and groundwater recharge occurring within a
country’s borders (UNSD, 2012). Thus the amount of internal renewable water
resources is equivalent to the sum of the surface runoff and groundwater recharge.
Water abstraction refers to the amount of water which is used in economic sectors
and the domestic sector. Abstraction must be distinguished from water which does
not return to the environment, either because it has evaporated or because it has
been incorporated in products or services.
Water use refers to the water received by economic and domestic sectors and which
is returned to the environment after use with some alterations in its composition (e.g
waste water). Use describes the total amount of water withdrawn from its source to
be used elsewhere.
Water consumption is the amount of water used which is not returned to the
original water source after being withdrawn. Water consumption also includes water
lost into the atmosphere through evaporation or transpiring from a product or plant
if it is no longer available for reuse (World Resouces Institute, 2013).
Outflow to sea: The difference between surface runoff and abstraction is the amount
of water which runs to the sea. In other words, outflow to sea = surface runoff -
abstraction + discharge of used water.
Distribution loss: This is the difference between production (supply) and use and
consumption.
Utilization: Utilization is made up of consumptive use (irrigation, households and
businesses) + non-consumptive use (incorporated into manufacturing products and
hydropower consumption).
The first step in water accounting is to define the spatial domain (Molden, 1997; Karimov et
al., 2012). Water stocks are classified by the SEEA-Water as surface water, groundwater and
soil water. Surface water is further disaggregated and includes artificial reservoirs, lakes,
rivers, snow, ice and glaciers. The net inflow is equal to the gross inflow minus the change in
storage. The gross inflow comprises of efficient precipitation plus surface water and
groundwater flows across the boundary. To avoid repetition, further explanation is provided
in the section on water accounts for Mauritius.
2.3 Water Accounts for Mauritius: Empirical Evidence
The Republic of Mauritius is an island fringed by coral reefs. It has a surface area of 1,870
km2 and a 322 km-long coastline. The island was formed as a result of a volcanic eruption
22
and, therefore, most of the rivers originate from the central plateau and flow toward the
sea.
The population of Mauritius is currently 1.2 million and GDP is MUR 323.2 billion (USD 9.1
billion) see Table 1. There are two seasons in Mauritius: winter, from May to October and
summer, from November to April. The average annual precipitation over the island is 2,000
mm. The water resource system is replenished during the summer season, when two-thirds
of the mean rainfall is captured by reservoirs (Government of Mauritius, 2014).
Table 1: Basic Statistics for Mauritius for 2013
Population (millions)
1.217
Urban Population (millions)
0.508
GDP at basic prices (MUR billions / USD billions)
323.2 / 9.1
Per capita GDP at basic prices (MUR / USD)1
265,603 /7,481
Annual real growth rate (%)
3.2
Mean annual rainfall (mm)
2,049
Annual fresh water abstraction (all recorded sectors)
(million m3)
Annual fresh water abstraction from surface water
(million m
3
)
608
487
Potable water produced (million m3)
217
(Metered) Potable water consumed (million m3)
96
Daily per capita domestic water consumption (liters)
165
Notes: 1 Exchange rate USD 1 = MUR 35.5
Source: Digest of Environment Statistics (2013), Digest of Energy and Water (2013) and National
Accounts of Mauritius (2013)
The water distribution systems and facilities have improved significantly over the last 30
years. At present, 99.6 percent of the population are connected to potable water. The
present domestic water demand is met from groundwater (55 percent), and surface water
(45 percent). However, despite these improvements, the water sector is currently facing
serious challenges in mobilizing additional water resources to meet the rising demand from
the growth in population and businesses. In addition, the impact of climate change is likely
to exacerbate the serious risk of water shortages.
According to a report by the National Economic and Social Council in 2014 (NESC, 2014),
some 200 million liters of treated drinking water are lost on a daily basis, mostly through
leaky underground pipes. On average, around 35-40 percent is lost in the distribution
network and around 10-15 percent is lost to faulty meters or illegal connections; a further 10
percent is explained by unbilled consumption, such as for fire fighting. This loss is equivalent
to about four times the annual capacity of the largest reservoir on the island. The waste of
such a valuable resource has been going on for decades.
This has serious repercussions for households, many of which have had to install water tanks
to ensure a continuous supply of water. The 2000 census for Mauritius recorded that 36.4
23
percent of households had a water tank or domestic reservoir. This figure rose to 48.1
percent in the 2011 census.6
2.4 Water Asset Accounts
There have been a number of initiatives to construct water accounts in Mauritius. In fact,
Statistics Mauritius has published a range of information pertaining to water assets and
flows in the Digest of Energy and Water Statistics (since 1999) and, more recently, in the
Digest of Environmental Statistics. In June 2015, Statistics Mauritius published its first annual
water account for Mauritius. The Southern African Development Community, in
collaboration with the European Union, compiled a training manual for ‘Economic
Accounting of Water Use’ in Mauritius in 2010 (Arntsen et al., 2010). In addition, the
Government of Mauritius and the Indian Ocean Commission (IOC) conducted an
experimental ecosystem natural accounting project for Small Island Developing States as
part of the Mauritius Strategy project in the Eastern and Southern Africa and Indian Ocean
(ESA-IO) region. This aim of the project was to test the feasibility of ecosystem and natural
capital accounting systems using data currently available in Mauritius (Weber, 2014a). With
technical assistance from the IOC’s ISLANDS project, a case study was developed to present
an overview of the first SEEA-Experimental Ecosystem Accounts and Natural Capital
Accounts of Mauritius. Natural capital accounts, compiled by Weber (2014a), include land
cover accounts, biomass-carbon accounts, water accounts, biodiversity of systems and
species accounts, and marine coastal ecosystem accounts. This study builds on previous
initiatives to construct water accounts for Mauritius.
2.5 Water Balance
Water data is often recorded on a hydrological year basis, which starts at the onset of the
rainy season. In Mauritius, the hydrological year starts in October and ends in September of
the following year. The hydrological year has been adjusted to align with calendar year
activities in other words, from January to December. For water accounting, it is assumed
that the water stock at the end of the year (pre-accounting year) and the water stock at the
beginning of the post-accounting year are equal. However, if the accounts are prepared on a
monthly basis, they may show the changes in stock arising from use and replenishment.
The total water from rainfall in Mauritius amounted to 3,821 million m3 in 2013 (Table 2).
Table 2 and Figure 2 show the fluctuations in rainfall over the period 2000 to 2013. The
lowest amount of precipitation for the period was in 2012. When water flows, part of it
flows over the land surface (Proag, 1994). The surface runoff for 2013 is estimated at 2,293
million m360 percent of the total water from rainfall. Water is partly depleted when it
evaporates, transpires or is directed to a sink where it cannot be used again (Chalmers et al.,
2012; Karimov et al., 2012). Evaporation is the conversion of liquid precipitation into water
vapor, which then returns to the atmosphere (Proag, 1994). Transpiration is the water loss
from plants and occurs when the vapor pressure in the air is less than that in the leaves. The
6 Households use water tanks and sometimes electrical pumps to cope with service interruptions and
insufficient pressure. This may affect the the quality of drinking water at the tap.
24
combined process is called evapotranspiration and is estimated at 1,146 million m3 (30
percent). The remaining water recharges the groundwater tables.
Table 2: Water Balance, 2009 to 2013 (million m³)
2008
2009
2010
2011
2012
2013
4,440
4,470
3,368
3,627
3,001
3,821
2,664
2,682
2,021
2,176
1,801
2,293
1,332
1,341
1,010
1,088
900
1,146
444
447
337
363
300
382
Source: Digest of Environment (Statistics Office)
Figure 2 further illustrates the fluctuations in surface runoff, evapotranspiration and net
recharge to groundwater over the last 10 years in Mauritius.
Figure 2: Total Rainfall in Mauritius, 2000 - 2013 (million m³)
Source: Digest of Environment Statistics (2013)
As Figure 2 shows, there is a close relationship between surface runoff, net recharge to
groundwater, and rainfall. Climate change, which may impact on precipitation, is therefore
also likely to affect surface runoff and net recharge to groundwater.
Water accounts are constructed for particular spacial domains in this case the island of
Mauritius. Figure 3 provides a map of Mauritius which shows the different amounts (or
distribution) of precipitation across the island for 2013.
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
2000 2002 2004 2006 2008 2010 2012
Rainfall Surface Runoff Evapotranspiration Net Rec harge to
Groundwat er
25
Figure 3. Distribution of rainfall in Mauritius in 2013
Source: Ministry of Energy and Public Utilities, Hydrology Data Book, 2005
As mentioned earlier in Section 2.3, economic accounting of water is separated into water
stock accounts and water flow accounts. Water stock accounts are divided into asset and
quality accounts. Asset accounts reflect the amount of total resource and changes in the
resource over the accounting period, while the quality accounts record stocks of water in
terms of its quality. Water flow accounts record the flow of water from the environment to
national economies.
Table 3 shows the water balance in Mauritius for the year 2013. The total amount of rainfall
– 3,821 million m3is divided into surface runoff, evapotranspiration and net recharge to
groundwater. Of the total amount of water from rainfall, 2,675 million m3 (70 percent) is
available for exploitation. This is obtained by subtracting the proportion which is attributed
to evapotranspiration. The total amount available for exploitation is divided into surface
runoff (2,293 million m3)and groundwater (382 million m3). The total water available, also
referred to as internal renewable resources, therefore corresponds to the sum of the annual
flow of rivers and recharge of groundwater generated from precipitation (UN, 2007) which
in this case amounts to 2,675 million m3.
3600mm
3000mm
1000mm
2000mm
PRECIPITATION - (mm)
26
Table 3: Water Balance in Mauritius, 2013 (million m³)
Water available
Water utilization
(1)
Rainfall
3,821
Surface runoff
2,293
Evapotranspiration
1,146
Net recharge to groundwater
382
(2)
Water available for exploitation
2,675
Surface runoff
2,293
Groundwater
382
(3)
Water sources for abstraction
608
Water utilization
in the economy
888
Surface water
487
Groundwater
121
(4)
Water for Hydropower
280
(5)
Water flowing to sea or to
ecological reserve (Flows to sinks)
Surface water
1,806
Groundwater to sea
427
Groundwater addition to closing
106.7
Source: Author’s calculations from Digest of Environment Statistics and Digest of Energy and Water
Statistics
From the water available for exploitation, water abstraction is estimated at 608 million m3.
The sources are made up of rivers (136 million m3), reservoirs (351 million m3) and
groundwater (121 million m3). From an economic perspective, water used for hydropower is
also important because it generates wealth; but since the water is returned to the water
cycle after utilization and therefore not removed from the total water available for
exploitation, it is not counted as an abstraction. The difference between water available for
exploitation and water abstraction shows the total amount which flows either to the sea or
to ecological reserves. This is referred to as ‘flow to sink’ in the SEEA-Water terminology
(UN, 2012). During the year, a certain amount of water consumption from surface water will
also flow to groundwater. This is accounted for in the flow account. Thus, surface water and
groundwater are the two sources for replenishing the stock of water in the economy.
27
2.7 Total Water Abstraction: Sources and Users
Water is abstracted for use from two sources: surface water runoff and groundwater. In
2013, 608 million m3 of water was abstracted (Table 4), of which 487 million m3 came from
surface water runoff and 121 million m3 from groundwater.
Table 4: Sources of Total Water Abstraction, 2008-2013 (million m³)
2008
2009
2010
2011
2012
2013
546
511
513
449
460
487
143
121
124
122
122
121
689
632
637
571
582
608
Source: Digest of Environment Statistics
Figure 4 shows water abstraction for the years 2000 to 2012. A comparison of Figure 2 and
Figure 4 reveals that the amount of rainfall has a significant influence on water abstraction.
Figure 4: Water Abstraction in Mauritius, 2000 to 2012 (million m³)
Source: Digest of Environment (Statistic Office)
Table 5 shows the water abstraction account for 2013 with further details on users. The left-
hand column shows the total amount used to generate economic activities, which amounts
to 888 million m3. The right-hand column, shows the uses of water and the sources for each.
Of the 888 million m3, 487 million m3 came from surface water and was used by the water
supply industry, the manufacturing industry and agriculture. 280 million m3 was used for
hydropower, implying a total surface water abstraction of 767 million m3. The remainder is
made up of groundwater, with figures showing the amount used by the water supply
industry, the manufacturing industry and agriculture. Table 5, excluding the hydropower
component, is similar in structure to a GPWA Statement of Water Assets and Water
Liabilities; the right-hand column shows the water assets while the left-hand column depicts
the water liabilities.
0
100
200
300
400
500
600
700
800
2000 2002 2004 2006 2008 2010 2012
Surface w ater Ground water To tal
28
Table 5: Water Abstraction Account, 2013
Water sources for abstraction
Utilization
Total water
abstraction
888
Total water utilization
888
Surface water
487
Surface water
487
Rivers
136
Water supply industry
112
Reservoirs
351
Manufacturing
7
Agriculture, forestry and fishing
368
Surface water to
Hydro
280
Hydropower
280
Groundwater
121
Ground water
121
Water supply industry
108
Manufacturing
6
Agriculture, forestry and fishing
7
Source: Author’s own calculations from Digest of Environment Statistics and Digest on Energy and
Water Statistics
2.8 Water Abstracted by the Water Supply Industry
The water supply industry supplies the economic and household sectors in Mauritius. Water
abstraction for these sectors is the main focus for investment strategies and pricing policies.
Following abstraction, the water is treated before it is distributed. Water withdrawl by the
water supply industry in Mauritius stood at 220 million m3 for the year 2013. As expected,
this amount is dependent on the storage system. There are 11 storage systems reservoirs,
dams and lakes which store water to be distributed to the population. Table 6 shows the
capacity of these reservoirs.
Table 6: Storage Capacity of Reservoirs in Mauritius
Reservoir
Capacity
(million m
3
)
District
Purpose
Mare aux Vacoas
25.89
Plain Wilhems
Domestic
Mare Longue
6.28
Plain Wilhems
Hydropower and irrigation
La Ferme
11.52
Black River
Irrigation
Piton du Milieu
2.99
Moka
Domestic
La Nicoliere
5.26
Pamplemousses
Domestic, irrigation and industrial
Tamarind Falls
2.3
Black River
Hydropower and irrigation
Eau Bleue
4.1
Grand Port
Hydropower
Diamamouve
4.3
Grand Port
Hydo-power
Dagotiere
0.6
Moka
Hydo-power
Valetta
2
Moka
Hydo-power
Midlands Dam
25.5
Moka
Domestic, irrigation and industrial
Total Storage Capacity 90.74
Source: Digest of Energy and Water (2013)
29
The distribution network in Mauritius works on a regional basis, with each of the reservoirs
(above) supplying particular networks or regions. There are six regions as shown in Table 7.
Table 7: Water Sources by Regions
Regions
Sources
Water for distribution
(million m³)
Mare Aux Vacoas (Upper)
Surface
43.2
Borehole
6.6
Total
49.8
Mare Aux Vacoas (Lower)
Surface
0.0
Borehole
30.0
Total
30.0
Port Louis
Surface
20.5
Borehole
13.2
Total
33.7
District water supply - North
Surface
26.3
Borehole
21.3
Total
47.6
District water supply - South
Surface
9.7
Borehole
16.7
Total
26.4
District water supply - East
Surface
9.4
Borehole
19.7
Total
29.1
Surface
109.1
Whole Island
Borehole
107.5
Total
216.6
Source: Digest of Energy and Water Statistics (2013)
The water resource system in Mauritius is highly influenced by seasonal variations in rainfall.
As mentioned earlier, the average annual precipitation over the island is 2,000 mm but the
rate of replenishment of the water resource systems differs across the year. Table 8 shows
the months when water levels are at their highest and lowest.
30
Table 8: Minimum and Maximum Water Levels in Mauritius
Reservoir
Capacity (million
m3)
Minimumas a
% of capacity
(month(s))
Maximum - as a
% of capacity
(month(s))
Mare aux
Vacoas
25.89
52
(January)
100
(April)
Midlands Dam
25.5
37
(January)
100
(March and
April)
La Ferme
11.52
21
(January and
November)
100
(March and
April)
Mare Longue
6.28
36
(January)
100
(April)
La Nicoliere
5.26
39
(October and
November)
100
(February to
May)
Piton du Milieu
2.99
27
(January)
100
(February to
April)
Source: Digest of Energy and Water (2013)
Table 9: Water Abstraction by Water Supply Industry, 2003-2013 (million m³)
Sources
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
Surface water
110
110
99
100
102
107
112
110
94
97
112
Groundwater
114
114
115
116
99
107
111
113
111
109
108
Total
224
224
214
216
201
214
223
223
205
206
220
Source: Digest of Environmental Statistics
Table 9 shows the amounts of water abstraction by the water supply industry over a ten year
period, from 2003 to 2013. A comparison with Table 2, reveals that only 8 percent of water
available is abstracted by the water supply industry annually. This indicates that Mauritius is
a water rich country.
Table 10 shows the uses of water from the water supply industry. This information
corresponds to the allocation of accounts according to the GPWA. As can be clearly observed
from the table, the distribution loss amounts to 110 million m3.
31
Table 10: Water Account for the Water Supply Industry, 2013 (million m³)
Water use by sectors
million m3
Domestic
73.36
Government
3.80
Acquired / concessionary prizes
0.01
Commercial
6.98
Hotels, guest houses
6.05
Industrial
3.78
Shipping
0.00
Vegetable and livestock producers
1.3
Sub-total
95.86
Total non-treated water
(agriculture/industrial)
15.4
2
Total water requirements from water industry
111
Distribution loss7
110
Water abstracted by Water Supply Industry
220
Source: Digest of Energy and Water Statistics (2013)
2.9 Physical Flow Account of Water: Supply and Use Table
Tables 11 and 12 show the supply and use tables for Mauritius in 2013. The work follows a
draft report and capacity building which was prepared by Statistics Mauritius with the
support of the UN Statistics Division (UNSD).8 The Physical Water Supply and Use Table
(PSUT) is based on the concepts outlined in Section 2.4 and contains relevant data on water
flows. The water supply table focuses primarily on the flow of water from the environment
to the economy, to households and the return flows back to the environment; while the use
table focuses mainly on the flow of water within the economy and household sector, and the
return flows back to the environment. Tables 13 and 14 present a simplified version of the
full PSUT. The household sector is treated separately from the economic sectors given that
water is used as an intermediate product in the productive sectors while it is consumed as a
final product in the household sector.
Flows of water in the economy are distinguished between household9 and economic sectors.
These sectors use water and at the same they supply water. We divide the economy into
seven sectors namely, agriculture and livestock, manufacturing services, hydroelectricity,
cooling of thermoelectricity, water utilities, sewage10 and household. The environment is
7 The term distribution loss follows the definition of the terminology for water accounts given earlier.
It does not necessarily mean that this amount of water is lost through leaky pipelines. It might also
pertain to commercial losses, i.e., faulty meters and illegal connections. Therefore, the meaning of
the term ‘distribution loss’ as used here is closer to the term Non-Revenue Water.
8 Our thanks go to Ricardo Martinez-Lagunes, Inter-Regional Advisor on SEEA at the UNSD, for having
made crucial data available to us.
9 The word ‘residential’, ‘household’ and ‘domestic’ are used interchangeably in this research report.
10 The sewage sector refers to man-made facilities to collect used water.
32
considered as an additional sector as it both supplies and uses water. Surface water (through
the environment) forms the bulk of the water supply to the economy and to households,
estimated at 767 million m3 in 2013. The second environmental component, groundwater,
supplies 212 million m3 (see Table 11).
Table 11: Supply Table for Water, 2013
SUPPLY
Agriculture and
livestock
Manufacture and
services
Hydroelectricity
Cooling
(thermoelectricity)
Water utilities
(drinking water)
Sewerage (sewage
collection and
treatment)
Households
Environment to
economy
TOTAL
Surface water
767 767
Groundwater
121 121
Total supply
888 888
Water supply
industry:
treated water
96 96
Water supply
industry:
non-treated water
15.4 15.4
Water supply
industry: loss
through distribution
108.6 108.6
Sewage to sewers
7
34
41
Sewage to
environment
28
28
Treated wastewater
21
41
62
Water returns to
the environment
114
280
394
Evaporation,
transpiration,
incorporation in
products
262 6 0 0 0 0 11.3 281
TOTAL 376 34 280 0 220 41 73 888 1025
Source: Author’s own calculations
A total of 888 million m3 of water is available for abstraction and hydropower (Table 5). Of
this, water utilities treat 220 million m3 of water, defined as potablewater. However, only
96 million m3 of water is consumed by households. The rest is a loss to the economy
reflected in water flow accounts as losses of waterwhich amounts to 124.1 million m3.
‘Losses of water’ are divided into the losses from the water supply industry of non-treated
33
waterwhich is distributed to the agriculture/manufacturing sectors and from
‘distribution loss’ attributed to ‘Non-Revenue Water’.
From the total of 767 million m3 of surface water supplied by the environment to the
economy, the agriculture and livestock sector consumed 368 million m3. This sector also
consumed 7 million m3 and 1.3 million m3 from groundwater and drinking water,
respectively. This equates to a total of 376 million m3. In the supply table (Table 12), this
water will have to flow to one or more sectors. While a significant proportion evaporates,
the rest is counted as a supply to an entity called water returns. Assuming a proportion for
evaporation, transpiration and incorporation in products, a total of 114 million m3 returns to
the environment. This is assumed to be ‘used’ by the environment in the use table. Water
for hydropower has a specific characteristic since it goes back to the environment after
being used. 280 million m3 is used for hydropower, which then flows back to the
environment water returns. The total water returns to the environment, therefore,
amount to 395 million m3. The manufacturing sector uses 34 million m3 of water from
surface water, groundwater and drinking water. This amount of water flows back to sewage
to sewers and treated wastewater. The household sector uses 73.4 million m3 of water. This
amount comes from the drinking water but then returns the water back to sewage to sewers
and sewage to environment.
Water is abstracted from surface water (reservoirs and rivers) and groundwater. The
agricultural sector was the main user of water (376.3 million m3), followed by the water
supply industry. In Mauritius, the water supply industry is composed of one central, public
agency, the Central Water Authority (CWA). Water abstracted by the CWA is mainly used for
drinking water purposes and accounted for 73.4 million m3 in 2013. Water was also received
by the sewerage sector and amounted to 41 million m3.
Return flows refer to water returned to the environment after use in agriculture (irrigation),
waste water or through distribution losses such as leaking pipelines. The return was
estimated at 395 million m3. The distribution loss amounted to 110 million m3 but is
recorded as 124 million m3 to take into account the non-treated water (15.4 million m3). The
distribution loss is equivalent to 50 percent of the total supplied by the CWA (220 million
). This figure is seriously high and poses questions about the management of the water
sector in Mauritius. However, this figure must be treated with caution since it does not
mean that 50 percent of the total water supplied is lost through leaky pipelines. As
previously mentioned, the category distribution loss also includes other forms of water
losses, such as commercial losses closely related to what is typically refered to as Non-
Revenue Water. The use table also shows that 41 million m3 of sewage flowed to sewers and
28 million m3 flowed to the environment. In addition, 62 million m3 of wastewater was
treated prior to discharge or reuse.
34
Table 12: Use Table for Water, 2013
USE (million m3)
Agriculture and
livestock
Manufacturing
and services
Hydroelectricity
Cooling
(thermoelectricity)
Water utilities
(drinking water)
Sewerage
(
sewage
collection and
treatment)
Households
Economy to
environment
TOTAL
Surface water 368 7 280 0 112
767
Groundwater 7 6 0 0 108
121
Total abstraction 375 13 280
220
888
Water supply
industry:
treated water
1.3 21 73.4 95
Water supply
industry:
non-treated water
15.4
Water supply
industry to the
environment,
including
distribution loss
108.6 108.6
Sewage to sewers
41
0 41
Sewage to
environment
28 28
Treated wastewater
62 62
Water returns to the
environment
395 395
Evaporation,
transpiration,
incorporation in
products
280 280
TOTAL 376 34 280 0 220 41 73.4 888 1025
Source: Author’s own calculations
The supply table shows that returns mainly comprised of sewage and water losses.
Households discharged 34 million m3 to sewers and an estimated 28 million m3 went directly
to the environment. The total amount of treated wastewater returns (62 million m3) were
from industries (21 million m3) and households (41 million m3). Water returns (395 million
m3) included 280 million m3 from non-consumptive use for hydropower and 114 million m3
from agriculture. Agriculture accounted for most of the consumptive use262 million m3
out of the total of 281 million m3.
35
It is important to add a caveat at this point. Some of the water flows, particularly the
returns, losses and consumptions were estimated as differences between other flows and
the total. For instance, the amount of water consumed in households was estimated by
subtracting the total wastewater discharged (sewage) from the water use (total received);
thus, balancing the supply and use columns, and row totals.
2.10 Water Abstraction at Regional and Seasonal Levels
Tables 11 and 12 provide an annual use and supply table for water. Given that around 3,821
million m3 of water was obtained through precipitation, 220 million m3 of water was
abstracted by the water supply industry, and 110 million m3 of water was consumed, it
appears that there is no visible water scarcity in Mauritius. Table 13 adjusts the amount of
water abstracted and water used by accounting for the 50 percent distribution loss (i.e.,
Non-Revenue Water). On average, water consumption stands roughly at 9.3 million m3 per
month (dividing the annual consumption by 12). This figure can then be compared with
water production on a monthly basis. Taking into account the loss of water which stood at
50 percentthe water available for consumption from the water utility service is estimated
at an average of nine million m3 per month. Compared with the monthly consumption of
water 9.3 million m3there is a gap of 0.3 million m3 a month. As shown in Table 13,
during the months of September, October, November, and February water production is
relatively low due to the limited seasonal rainfall. These are periods of water scarcity.
Households in certain regions of Mauritius do not have 24 hour access to water and often
experience severe cuts in supply.
Table 13: Estimates of Water Requirements and Water Production on a Monthly Basis
Month
Monthly water
production million
m
3
Monthly water available
for consumption million
m
3
Monthly water
requirements - million
m
3
Jan
18.0
9.0
9.3
Feb
16.6
8.3
9.3
Mar
19.7
9.9
9.3
Apr
18.9
9.5
9.3
May
19.5
9.8
9.3
Jun
18.0
9.0
9.3
Jul
18.5
9.3
9.3
Aug
18.2
9.1
9.3
Sep
17.2
8.6
9.3
Oct
17.2
8.6
9.3
Nov
16.9
8.5
9.3
Dec
17.9
9.0
9.3
Source: Statistics Mauritius and author’s own estimates
Figures 5,6 and 7 illustrate water shortages in three regions of Mauritius: the North, South
and Central regions. These figures show that while the level of water from the water supply
industry is much higher than the level of potable water consumption, accounting for
36
distribution losses (i.e., Non-Revenue Water) of around 50 percent makes a significant
difference. In fact, with the level of distribution losses, the current level of available water is
nearly equivalent to water demand. During the months of December to January, a significant
drop in water abstraction is observed, implying an associated fall in consumption.
Figure 5: Production of Potable Water Versus Water Demand, Northern Region
Source: Information from Central Water Authority and author’s own estimates
Figure 6: Production of Potable Water Versus Water Demand, Southern Region
Source: Information from Central Water Authority and author’s own estimates
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
Jan-10
Mar-10
May-10
Jul-10
Sep-10
Nov-10
Jan-11
Mar-11
May-11
Jul-11
Sep-11
Nov-11
Jan-12
Mar-12
May-12
Jul-12
Sep-12
Nov-12
Jan-13
Mar-13
May-13
Jul-13
Sep-13
Nov-13
Jan-14
Mar-14
May-14
Jul-14
Sep-14
Nov-14
Mm3
Year 2010-2014 Water Consumption
Total Portable Water
Accounting for 50% losses
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
Mm3
Year 2010-2014 Water Consumption
Total Portable Water
Accounting for 50% losses
37
Figure 7: Production of Potable Water Versus Water Demand, Central Region
Source: Information from Central Water Authority and author’s own estimates
Shortages of water are witnessed mainly for the north and the south as shown in figures 5
and 6. The water situation is particularly acute for the southern region of the island, where
water consumption in some months is greater than water production implying water has
to be transferred from other reservoirs to satisfy the demand in this region.
2.11 Seasonal Water Accounts
Tables 14 to 18 show the water accounts for the summer and winter seasons. Around 77.5
percent of rainfall is observed in the months from November to April; and the remainder in
winter, from May to October. Table 14 shows the uneven distribution of rainfall between the
seasons in 2013: 2,072 million m3 of water was available for exploitation in summer and 862
million m3 in winter. 455.2 million m3 and 152 million m3 of was abstracted, respectively, in
these two periods.
Table 14: Seasonal Water Balance, 2013 (million m³)
Summer
Winter
Rainfall
2,960
862
Surface runoff (million m3)
1,776
517
Evapotranspiration (million m3)
888
258
Net recharge to groundwater
296
96
Water available for exploitation
2,072
613
Surface runoff
1,776
517
Groundwater
296
96
Water resources abstracted
455.4
152.7
Surface water
393.6
93.5
Ground water
61.8
59.2
Source: author’s own calculation
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
Mm3
Year Water consumption
Portable Water Production
Accounting for 50% losses
38
Table 15 shows the total water abstraction on a seasonal basis for 2013. Surface water
available for abstraction varies significantly: 393.6 million m3 in summer and 93.5 million m3
in winter. The agricultural and forestry sub-sector is most vulnerable in the winter season
when precipitation levels are at their lowest.
Table 15: Total Water Abstraction on Seasonal Basis, 2013 (million m³)
Water sources for abstraction Water utilization Summer Winter
Surface water
393.6
93.5
Water supply industry (CWA)
57.1
55
Manufacturing
4
3
Agriculture, forestry and fishing
332.5
35.5
Surface water to hydro
219.0
61.0
Groundwater
61.8
59.2
Water supply industry (CWA)
54.4
53.6
Manufacturing
3.4
2.6
Agriculture, forestry and fishing
4
3
Total
601
287
Table 16 shows water abstraction by the water supply industry. The demand for the
different sectors is more or less constant, implying that the uneven distribution of rainfall
must be stored to allow a consistent distribution during the year.
Table 16: Water Abstraction by Water Supply Industry on a Seasonal Basis, 2013 (million
m³)
Water users
Million m3
Summer
Winter
Domestic consumers
37.3
36.1
Business consumers
3.5
3.4
PSA consumers
1.9
1.9
Industrial
1.9
1.9
Agricultural
1
0.3
Commercial consumers
3.0
3.0
Concession price
0.0
0.0
Religious and charitable
0.3
0.3
Sub-total
48.6
47.3
Total non-treated water (agriculture/Industrial)
7.8
7.6
Total water requirements from water industry
56.4
54.9
Distribution loss1
53.9
54.1
Water abstracted
110.3
109.0
Note: 1 Distribution loss refers to the category used by the SEEA and is in fact closer to Non-Revenue
Water, as previously discussed
Source: author’s own calculation