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Center for Environmental Systems Research
University of Kassel
Water Use in Semi-aridNortheastern Brazil
Modeling and Scenario Analysis
.Maike Hauschild Petra Dll
.KASSEL WORLD WATER SERIES REPORT No 3
University of KasselCenter for Environmental Systems Research
. .Kurt-Wolters-Strae 3 34125 Kassel Germany.Phone +49.561.804.3266 Fax +49.561.804.3176
[email protected] http://www.usf.uni-kassel.de
Cover design by Maike HauschildCover photographs by Maike Hauschild and Petra Dll
Water Use in Semi-arid Northeastern Brazil
Modeling and Scenario Analysis
Maike Hauschild, Petra Dll
Center for Environmental Systems Research
University of Kassel
Water Availability and Vulnerability of Ecosystems and Society in the Northeast of Brazil
Brazilian-German cooperation program
financed by CNPq and BMBF
May 2000
The Kassel World Water Series:
Report No 1 A Digital Global Map of Irrigated Areas
Report No 2 World Water in 2025
Report No 3 Water Use in Semi-arid Northeastern Brazil
Water Use in Semi-arid Northeastern BrazilKassel World Water Series. Report Number 3
Report A0003, May 2000
Center for Environmental Systems ResearchUniversity of Kassel 34109 Kassel Germany
Phone +49.561.804.3266 Fax [email protected] http://www.usf.uni-kassel.de
Please cite as:
Hauschild, M., Dll, P. (2000): Water Use in Semi-arid Northeastern Brazil Modeling and Scenario Analysis. ReportA0003, Center for Environmental Systems Research, University of Kassel, 34109 Kassel, Germany.
Hauschild and Dll Water Use in Semi-arid Northeastern Brazil Modeling and Scenario Analysis
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Abstract
If water is a scarce resource like in the semi-arid Northeast of Brazil, the water use as well as
water quality must be managed in a proactive manner. In order to achieve a sustainable
development of the region, water management decisions should be based on an assessment of
future water use which includes the long-term effects of current activities and policies. In order to
support water management decisions, we performed a scenario analysis of future water use in
Piau and Cear in 2025 by
1. compiling, analyzing and integrating information about water use and water management in
Piau and Cear,
2. developing the large-scale water use model NoWUM which covers the whole of Piau and
Cear and provides sectoral water use estimates for each municipality, and, using NoWUM,
3. computing current (1996/98) water use,
4. deriving water use scenarios for the year 2025, which reflect different possible societal
development paths and water demand management options, and
5. computing water scarcity indicators which show which municipalities will suffer most from
water scarcity.
For all sectors, the increase of water use between today and 2025 is higher in case of the Coastal
Boom and Cash Crops scenario than in case of the Decentralization scenario. Due to increased
water use (in 99% of the municipalities), water scarcity will become more severe in the future,
even though runoff will increase in more than 50% of the municipalities due to climate change
(average climate 2011-2040). The development of water use will predominantly be influenced by
the development of the irrigation sector, above all the extension of irrigated areas. As a first
indicator of water, scenarios of municipal nitrogen loads were computed. Future municipal
nitrogen loads could be smaller than today's if 70% of the waste water in the capitals of the
municipalities is subject to secondary treatment, as steep increase from today's coverage. The
presented scenario analysis can form the basis for further investigating the effect of water
management measures on water use, water scarcity and water quality.
Hauschild and Dll Water Use in Semi-arid Northeastern Brazil Modeling and Scenario Analysis
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Contents
1 Introduction _______________________________________________________________________ 72 Methodology_______________________________________________________________________ 8
2.1 Large Scale Water Use Model NoWUM ____________________________________________ 82.2 Estimation of nitrogen loads ____________________________________________________ 102.3 Water use scenarios for 2025 ____________________________________________________ 11
3 Results __________________________________________________________________________ 143.1 Water use in 1996/98 ___________________________________________________________ 143.2 Water use in 2025 _____________________________________________________________ 183.3 Water scarcity ________________________________________________________________ 243.4 Water quality _________________________________________________________________ 27
4 Summary and conclusions __________________________________________________________ 285 References _______________________________________________________________________ 30
Appendix A: NoWUM model description
A1 Overview _______________________________________________________________________ 33A2 Irrigation water use_______________________________________________________________ 34
A2.1 Method_____________________________________________________________________ 34A2.2 Climate data input ___________________________________________________________ 34A2.3 Input of crop data____________________________________________________________ 34A2.4 Calculation of irrigation water use______________________________________________ 38
A3 Livestock water use _______________________________________________________________ 39A4 Domestic water use _______________________________________________________________ 40
A4.1 Method_____________________________________________________________________ 40A4.2 Input data of population and public water supply volumes__________________________ 40A4.3 Computation of domestic water use _____________________________________________ 43
A5 Industrial use____________________________________________________________________ 44A5.1 Methods and calculation ______________________________________________________ 44A5.2 Input data __________________________________________________________________ 45
A6 Tourism water use________________________________________________________________ 48A6.1 Method and calculation _______________________________________________________ 48A6.2 Input data __________________________________________________________________ 48
A7 Model input _____________________________________________________________________ 51A8 Model output ____________________________________________________________________ 51A9 References ______________________________________________________________________ 52
Appendix B: Maps and municipality values of modeled water use
Municipality map of Cear 1996 _______________________________________________________ 57Municipality map of Piau 1996________________________________________________________ 59B1 Withdrawal water use of present state 1996/1998 _______________________________________ 61B2 Consumptive water use of present state 1996/1998 ______________________________________ 65B3 Withdrawal water use of 2025 Coastal Boom and Cash Crops scenario (RSA)_______________ 69B4 Withdrawal water use of 2025 Decentralization scenario (RSB)___________________________ 73B5 Withdrawal water use of 2025 Coastal Boom and Cash Crops intervention scenario (ISA)_____ 77
Hauschild and Dll Water Use in Semi-arid Northeastern Brazil Modeling and Scenario Analysis
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1 Introduction
Scarcity of water is a major constraint for development in semi-arid Northeastern Brazil, a region
characterized by recurrent droughts which are related to the El Nio phenomenon. In particular
the rural population, mainly subsistence farmers, suffers from these droughts due to the loss of
crops and livestock. During the last decades, irrigated agriculture has been regarded as the
privileged development option for rural areas, with plans for a multitude of irrigation projects
which have rarely been realized. Nevertheless, the irrigation sector has become the largest water
user in Northeastern Brazil. Today, hopes are high that an extended production of irrigated fruits
for export will strongly improve rural incomes.
For the rural population, access to safe drinking water is difficult and becomes even more
difficult during droughts, as only the urban population (or rather a part of it) is connected to the
public water supply. The public water supply system has, in most cases, problems with serving
the ever increasing number of urban dwellers who, given the convenience of tap water, consume
relatively high amounts of water. In some areas today, and probably more in the future, industry
and tourism are important water user that compete for water with the irrigation sector.
Under the described conditions in Northeastern Brazil, it is necessary to manage both water
supply and water demand. While the construction and proper management of water infrastructure
is the necessary basis for a secure water supply, a concurrent water demand management is
essential for a sustainable economic and social development of the region. Only by a proactive
demand management can the scarce resource water be used efficiently.
Water demand management requires an assessment of present and future water use in which
water use is related to development paths and policy opt