Proposal of SCWMI as a Water Sustainability Index for Water

Solutions for Water platform - World Water
Forum 6th - Marseille 2012
Water Sustainability Indexes and Water Governance
Proposal of implementation of an
SPATIAL COVERAGE WATER
MONITORING INDEX – SCWMI.
MIDAGLIA, CARMEN LUCIA VERGUEIRO (1); CETESB, S. PAULO, BRAZIL
OVANDO CRESPO, CRISTINA KAREN (2); UMSS, COCHABAMBA, BOLIVIA
PÉREZ MACHADO, REINALDO PAUL (3); USP, S. PAULO; BRAZIL
Solutions for Water Platform: Proposal of implementation of an SPATIAL
COVERAGE WATER MONITORING INDEX – SCWMI.
Main Objetive: To introduce SCWMI (MIDAGLIA, 2009) as an index that interprets and summarizes
CETESB-São Paulo State Environmental Agency monitoring network through the evolution of its
coverage by means of the spatial density of network monitoring and the respective average values for
the IQA - Índice de Qualidade de Água (Water Quality Index) by establishing a comparison between
the population growth through the evolution of the population density rate in the state of São Paulo
and also as a function of the macro land use. The consequences of such growth may be seen through
spatial analysis operations the aim of which is at establishing an index factor which summarizes the
adjustment and the network spatial scope supported by a geo-processing platform developed in the
ILWIS 3.4 (Integrated Land and Water Information System, (ITC, 2004). Such index would analyze
whether the amount of the points monitored has kept the spatial capacity of representing the
conditions of the quality of the water in function of the anthropogenic pressure found by the growth
and densification of the urban areas in the State over water bodies and the possible loss of its
ecological integrity. Examples of some of points used at CETESB monitoring water quality network are
seen in the following pictures: SORO 02100,PARP 02750, PCAB 02100, TAMT 04900 and COTI 03800.
It could be used together with others Water Sustainability Indexes for Water Governance.
SP WATER MONITORING
POINTS:30 YEARS OF WATER
QUALITY INDEX RESULTS
(CETESB)
SORO 02100- Rio Sorocaba, Ponte PingaPinga, em Sorocaba.
PCAB 02100 -Rio Piracicaba, na captação de
água de Americana,
PARP 02750- Rio Paranapanema, 800 m a
jusante da barragem de Capivara
TAMT 04900 - Rio Tamanduateí,
Ponte na Av. Santos Dumont, SP
COTI 03800 Rio Cotia,
Ponte na Rod.
Raposo
Tavares, Km
28.5
ANALYSIS
of
the
ANTHROPIC
PRESSURE OVER the SURFACE WATER
MONITORING NETWORK OF SÃO
PAULO STATE (Brazil) by MEANS of
MULTI-CRITERIA EVALUATION and A
SPATIAL
COVERAGE
WATER
MONITORING INDEX – SCWMI
Fig.1
São Paulo State,
Brazil
Problem Definition:
The network for monitoring the quality of surface waters is an important tool in the state
management of the quality of water evaluation for its background and geographical distribution.
But how to know if has a adequate spatial distribution?
SCWMI index comparatively evaluates the spatial evolution of such network in the interior of the
state of São Paulo, Brazil (Fig.2) through the number of point samples and its respective spatial
density in 30 years and the demographic growth, through average population density of the
municipalities included in the 22 existing UGRHIs- (Unidades Gerenciamento de Recursos
Hídricos), local acronym for WRMUs-Water Resources Management Units. The proposed new
index has analyzed whether the amount of monitored points has annually kept the spatial
capacity to represent the quality of water conditions as a function of the intense anthropogenic
pressure found due to the growth in urban areas within the state over the water bodies, and also
the possible loss of its ecologic integrity. The resulting vulnerability maps might be able to show
whether it is necessary to increase or reduce the network. Else, which WRMUs need more
investments in environmental protection or recuperation. The Rational Structuring of SMCE
(Spatial Multicriteria Evaluation) for IAEM- Índice de Abrangência espacial do
monitoramento/SWMI Index is show at Fig. 2- Racional Framework for Multi-criteria evaluation.
Fig.2
Methodology: Managing the spatial water information:
The SMCE tree is loaded using base rasters maps (obtained through point interpolation
processing operation). Both population density and the Water Quality Index results maps
used moving average limit distance of 15km and 150km respectively. Then, for each
potential area, a suitability map of the main indicators is generated using the ILWIS GIS.
After they are sliced in 5 classes. They can be used either to rate the scope coverage and
the potential anthropic pressure over rivers and reservoirs, as show the fig.3:
SCWMI-Spatial Coverage
Water Monitoring Index
Antropic Pressure
over Water
Management Classes
Intervals
Fig.3
Insuficient
0
0,355
Classes
Vulnerable
Sustaintability of Water
Management Issues
High vulnerability to
antropic pression
Fair Coverage
0,356
0,505
Significant Vulnerability
Suficient
0,506
0,605
Sustaintable
Good Coverage
0,606
0,755
Wide Scope
0,756
1
Not Vulnerable
Good Sustaintability
No Current Vulnerability
The macro main land use added to the SMCE model is the same for the all the period tested.
Although it can be assumed that it has obviously changes, the SP WMUs main attribution state
by the law SP 9.034/94 still can be considered real for such large units. So it is used to ponders
the population growth among the 4 different kinds of major land use vocation. Value classes are
specified to corresponding units ranging from : 1 – conservation; 2- agricultural; 3- in
industrialization process and to 4 – industrial vocation, that is the one that might cause more
impacts. Else, once land use is still fixed, it is good because the model can work showing better
the affects of urbanization, the status of water quality and the network coverage progress. Fig.4
shows
the
selection
of
maps
to
generate
2010
SCWMI
scenario.
Fig.4
SCENARIO 2010 to estimate the SCWMI for São Paulo State, Brazil
Number of
Points 2010
(weight 0,25)
Network
Density 2010
(weight 0.75)
+
X
Populational
Density 2010
(weight 0,70)
2010 Water
Quality Index
Moving
Average 2010
=>
=> Resulting SMCE
Index from decision
tree / ILWIS 3.4
+
x 0,45
Index classes
Spatial
Slicing to
SCWMI
Antropic
Pressure Index
2010
x 0,45
=>
Macro Land Use (weight 0,30)
X
x 0,10
=>
+
Water
Management
index 2010
2010 SCWMI –
Spatial Coverage
Water Monitoring
index Map /
Once at the criteria tree, it’s possible to chose among 3 available methods : direct, pair wise
comparison and rank order to weight the model concerning the importance of the selected
factors. It’s was decided to use the direct method for assigning weights for 2 of the 3
intermediate index cause they are mainly quantitative technical criteria, showing real data,
measured for governmental agencies. Then, suitability maps for each sub-criterion are
generated and crossed at SMCE criteria tree at ILWIS 3.4 (http://52north.org)..
Once the idea was to make a confront about the human factors X the environmental factors
(water quality) both have the same weight (0,45) Only for the Water Management Issues it
was used a pairwise comparison, where the water density network was considered moderately
more important than the number of points. Although density shows the relation points/ areas,
the number of points were import to show differences among the units at the beginning of the
network, in 1970 to 80, when the coverage was not very wide. Further one can be used to
measure the economical cost of the water network. It was assigned it a 0.10 weight, cause
only good water management was help to monitor the confront above be understood as a
benefit.
The Fig. 5 shows the criteria tree with the main problem definition fulfilled with indicators raster
maps:
Fig.5
SCWMI: To estimate the antropic pressure over SP surface water
monitoring network coverage
(vulnenability)
SCME (Spatial Multi-Criteria Evaluation) model for SCWMI comparasion (software ILWIS
3.4). Midaglia, 2011
Results:
For effect of interpretation of the results generated, a slicing process was carried out. The SCWMI index
interval divided in 5 suitability classes and grouped into 2 categories: the vulnerable or non-vulnerable,
which defines the degree of the network spatial scope and its vulnerability in face of the anthropogenic
pressures.
It is noticed that this fact predominates in WRMUs of industrial nature or in process of
industrialization (macro land-use), where the majority of the about 40 millions population of the state is
found, specially I urban densely areas.
Within those areas, the problem is not the absence of the
monitoring process rather the existence of stretches of critical rivers (bad or poor IQA-Water Quality
Index), because many of them have already been detected by the monitoring network in its early years
and that still remained. In 1980, with few points the vulnerable degree are was worst. Later, with more
points, the stressed and polluted area was better shaped. The index also could not map any non
vulnerable area in 1980. One of these example is WRMU 6 – Alto Tietê, where the point TAMT 04900, at
the very center of the city of São Paulo, has the worst score (0.21) for 1980 and (0.27) for 2011, which
means high vulnerability and risk, and very poor water quality influenced by human activity without proper
sewage treatment. like the WRMU 6 – Alto Tietê.. The following maps shows the scenarios: Map 1 –
SCWMI 1980, Map 2 -SCWM1992, Map 3 –SCWM 2002, Map 4 –SCWM 2010 and Map 5 –SCWM
2011..
Map.1
SP 1980 SCWMI MAP with
annual IQA average
Source: SP_WATERNET.
Map.2
SP 1992 SCWMI MAP with
annual IQA average
Source: SP_WATERNET.
Map.3
SP 2002 SCWMI MAP
with annual IQA average
Source: SP_WATERNET.
Map.4
SP 2010 SCWMI MAP
with annual IQA average
Source: SP_WATERNET.
Map.5
SP 2011 SCWMI MAP
with annual IQA average
Source: SP_WATERNET.
On the other hand, SP north coastline that presents a very high density of points, good water quality index
average, is therefore with good sustainable SCWMI index rates. In this case, taking into account the past
scenarios, a reduction of the number of monitoring points would be advisable in order to optimize the
monitoring network resources in this region. The index might be applied over the time to reduce the
number of observation points and save resources assigned from sustainable areas, redirect it to others
more vulnerable areas, or to where the land use dynamic challenges a better water management process.
The water monitoring network shall aim at having the best coverage in the state as a whole and provide a
realistic portrait of water quality status. The following pictures show the contrast concerning the presence
of pollution:
Ex: bad water quality status
Ex: Very good water quality status
Conclusions:
The SCWMI index was capable to identify areas according the monitoring network density, quality
of the water and water vulnerability to anthropogenic pressure. The SCWMI reading found that
the São Paulo (CETESB) monitoring inland waters network grew so as to be present in all units
(as of 2001), and that regarding territory, they were found to be adequate in most of the period
evaluated. It has increased from 84 to 354 (2011) points and reached the density by the CEE
criterion (EEA Directive). But comparison between the selected years shows that even tough the
network is spreading all over São Paulo State, the population growth is pressuring the water
resources specially at urban areas with high population density. So, it still appears vulnerable to
high anthropogenic pressure over water bodies due to the multiple use of water resources and
the economic activities in the region for greater economic development in the country.
During the 30 years studied, the history of monitoring of surface water in the State of São Paulo
was told with the resulting index of the combination matrix comparing social and environmental
factors and the SCWMI can analyze the territorial dimensions to classify the Water Management
Units as for their vulnerability in terms of monitoring, showing the unequal coverage of the
network in the territory in which it operates, one of the regions with more pressure for the
multiple use of water in Latin America. Therefore can be great contribution to water management
solutions processes.
References:
• CETESB- Companhia Ambiental do Estado de São Paulo http://www.cetesb.sp.gov.br/agua/aguassuperficiais/35-publicacoes-/-relatorios
•EUROPEAN ENVIRONMENT AGENCY - EEA. EUROWATERNET – The European Environment Agency’s
Monitoring and Information Network for Inland Water Resources. Technical report nº 7. Copenhagen, junho
de1998. www.eea.europa.eu/publications/TECH07/tech07.pdf
•ILWIS 3.7 - http://52north.org/communities/ilwis/about
• ITC - INTERNATIONAL INSTITUTE FOR GEO-INFORMATION SCIENCE AND
EARTH OBSERVATION. Spatial Decision Support Systems: Distance Education. 2 CD’s. Enschede, NL, 2008.
•MIDAGLIA, C. L.V. 2009. Proposta de Implantação do Índice de Abrangência Espacial de Monitoramento IAEM por meio da Análise da Evolução da Rede de Qualidade das Águas Superficiais do Estado de São
Paulo.2009. 230 f.. Tese de Doutorado – Programa de Pós-Graduação do Departamento de Geografia.
Faculdade de Filosofia, Letras e Ciências Humanas da Universidade de São Paulo – USP
http://www.teses.usp.br/teses/disponiveis/8/8136/tde-03022010-165719/
•MIDAGLIA,C.L.; TASHIBANA, E.; KAWAKUBO, F. Análise da Pressão Antrópica Sobre A Rede de
Monitoramento das Águas Superficiais do Estado de São Paulo por Meio da Avaliação Multi-Criterio e do
IAEM-Índice de Abrangência Espacial do Monitoramento. Anais do Simpósio Internacional: Anais do II
SIMPÓSIO INTERNACIONAL CAMINHOS ATUAIS DA CARTOGRAFIA NA GEOGRAFIA 12 /2010
http://www.2cartogeo.com.br/Anais_2CARTOGEO.pdf