Abstract
From 2013 to 2015, the Brazilian southeast region experienced the most severe and intense drought recorded, the Water Crisis. This outstanding drought led the government to make efforts toward an adequate water resources management. In Campinas, the third most populous city of the State of São Paulo, the government proposed the Campinas Water Resources Master Plan (CWRMP), the main objective of which was to ensure the quantity and quality of water, reducing water vulnerability in the municipality. In this study, we evaluated the effectiveness of this plan through the major guidelines into four actions: (1) increase the permeability rate and the soil infiltration capacity, (2) increase the vegetation cover, (3) improve the sanitation services, and (4) minimize the number of contaminated areas. For Actions 1 and 2, we inferred that the aforementioned parameters have increased after the CWRMP enactment. About the Action 3, we found that Campinas has historically provided good sanitation services to the population, regardless of the CWRMP promulgation. However, more improvements should be given to waste collection and recycling services. The underground water consumption also has to be regulated, as significant exploitation has no legal permit. Finally, considering Action 4, the number of contaminated areas was reduced in the available data period. Therefore, the CWRMP was considered a valuable initiative to support an integrated and sustainable use of water, improving the water resources management in Campinas.
HIGHLIGHTS
The 2013–2015 water crisis was the most severe drought recorded in the southeastern region of Brazil.
The CWRMP was enacted to ensure the water quantity and quality, reducing its vulnerability in Campinas.
The CWRMP actions have been effective to restore the local vegetation cover.
The CWRMP was a valuable initiative for the water resources management of Campinas.
Graphical Abstract
INTRODUCTION
Drought is defined as a prolonged dry period, which affects different components of the hydrological process, and the productive sectors of society. This natural hazard causes adverse impacts to human beings (i.e., water resources, agriculture, and livestock supply), which results in famine, energy rationing, blackouts, and contributes to increased incidence of social conflict (Getirana, 2016). Also, the rapid growth of population and industry magnify these impacts due to the water demand increase, becoming a huge challenge for urban water planners (Missimer et al., 2014; Bharti et al., 2020; Bischoff-Mattson et al., 2020).
In Brazil, drought episodes have been reported since 1500 (Lemos, 2003), mainly in the northeast region. However, in the southeast region, the drought events have been more frequent in the last 50 years. It affected the water supply for the Metropolitan Area of São Paulo in 1985 (Araújo, 1986) and was responsible for the Brazilian blackouts between 1999 and 2001 (Cavalcanti & Kousky, 2001). From 2013 to 2015, the southeast region experienced the most severe and intense recorded drought. The rainfall regime of this region is affected by (1) the South Atlantic Convergence Zone (SACZ); (2) the South Cold Fronts (SCFs); and (3) the Low Level Jets (LLJs). The SACZ is a broad axis of clouds, precipitation, and convergent winds, with a northwest–southeast orientation across southeastern Brazil to the southwestern Atlantic Ocean (EumeTrain's, 2014). Regarding the SCFs, they create strong unsteady atmospheric thermodynamic conditions, while the LLJs transfer the Amazon humidity to the Brazilian southeastern and southern regions (Nobre et al., 2016). When those three mechanisms act together, the average rainy season over southeast Brazil starts, between October and April. However, an intense, persistent, and anomalous high-pressure system occurred in the southeast region in 2013/14 summer, not allowing the action of those mechanisms, which resulted in low rainfall levels (Nobre et al., 2016).
In the city of São Paulo, the rainy season is between December and March. From 1981 to 2014, the average accumulated rainfall between these months was 918.7 mm with lower and upper terciles equal to 827.6 mm and to 984.8 mm (Coelho et al., 2016). During the rainy season of 2013/14 and 2014/15, the total precipitations were equal to 439.0 mm and to 692.8 mm, respectively (Coelho et al., 2016). The probability of observing a total precipitation lower or equal to the former value during a rainy season is 0.01%, whereas to the latter is 7.13% (Coelho et al., 2016). These probabilities values show how extreme and rare this drought was, highlighting the 2013/14 (not) rainy season. This situation led into a fast depletion of the reservoirs located in the Brazilian southeastern region, and a substantial reduction in their major river flows (Nobre et al., 2016), causing the unprecedented drought situation that has been popularly called the Water Crisis.
The Water Crisis affected the Brazilian economy, totalizing an approximate of 5-billion-dollar loss in different productive sectors (Munich RE, 2015). In the agricultural sector, Gomes (2014) highlighted the reduction of 20.0% in the sugarcane harvest in 2014 compared to the year before, from 40 to 32 million tons. In the energy sector, the low water levels of the reservoirs affected hydroelectric energy production, which is the Brazilian main energy source, and motivated the government to activate thermoelectric power plants to complement the energy production. This decision made the electricity cost go up in 2013 and 2014, which contributed to increase inflation by 0.3%, and raised the electricity cost by about 15.0% at the beginning of 2015 (Amato, 2015; Laporta, 2015). Hence, the electricity cost reduced the mineral sector production, especially of aluminum, which was diminished by 20.0% (Cerqueira et al., 2014).
In Campinas, the third most populous city of the State of São Paulo (about 1.20 million inhabitants) (Brazilian Institute of Geography and Statistics – IBGE, 2020), the Water Crisis caused water shortage. In order to face this problem, the urban water planners adopted the traditional actions against drought events, such as intermittent and rotation water supply. The Resolution 50 of the National Water Agency (ANA) and the Department of Water and Electricity of São Paulo State (DAEE) established rules for the minimum flow for the impacted basins. Because of restriction, the water supply consumption was reduced by 20% and the industrial and agriculture, by 30% (ANA and DAEE, 2015). It affected 261,000 inhabitants, interrupted commercial activities, and caused a 15.5% increase in the grocery average price (Globo, 2014a, 2014b). Several industries drilled tubular wells to supply their activities, as well as in rural areas, for irrigation purposes (Pinhatti et al., 2015). However, only about 40% of them have legitimate right to exploit underground water, making it very challenging for the authorities to regulate and manage water resources in the area (Hirata, 2018). The negative impacts also reflected on the tourism as many recreational activities in the reservoirs surrounding Campinas were interrupted (Victor et al., 2018). In the Atibaia River, which is the main watercourse of the city, the capacity for pollutants diluting and self-purifying decreased due to its low flow and caused fetid odor occurrence in some of its streams and tributaries (Globo, 2015). Thus, the Concessionaire of Water and Sewage of Campinas (SANASA) increased the water treatment cost by 60.0% in 2014 and 2015 (Menezes et al., 2018).
The Water Crisis highlighted the need for the long-term planning of water management in Campinas, in order to ensure the availability of water for human and animal consumption, irrigated agriculture and industry. Also, according to the Brazilian Federal Constitution (Brazil, 1988), public managers have the duty of defending and preserving the ecologically balanced environment. Therefore, the urban water planners and SANASA proposed the Campinas Water Resources Master Plan (CWRMP) in 2014, which was concluded in 2016.
The CWRMP comprised the evaluation of the current water resources scenario and proposed conservation and restoration actions by the use of structural and non-structural measures, whose main objective was to ensure quantitative and qualitative water security (City Council of Campinas – PMC, 2016). The CWRMP diagnostic of the water resources scenario at the time was based on the analysis of the natural, social & environmental, and institutional axes. The first axis concerned the assessment of the physical and biological aspects, aiming to characterize areas with potential environmental losses, such as the erosive processes or floods, and vegetated areas, especially riparian forests (PMC, 2016). The social & environmental analysis regarded the assessment of the social, economic, and demographic aspects, which were able to evaluate the social water quality perception (PMC, 2016). The institutional analysis performed an assessment of Campinas government structure in terms of material, human, and financial resources, and also the assessment of its water resources legislation (PMC, 2016).
Several papers are found in literature about the benefits of enhancing the water master plans and policies for drought and flood response. King-Okumu et al. (2018, 2019) presented the improvement of the local community resilience driven by the local water resource development planning in Kenyan arid lands. Karavitis (1999) used decision support systems to find the most appropriate solutions for Athens, Greece, based on an integrated drought planning and management strategy. Browne et al. (2012) showed that, in Canberra, Australia, a master plan was developed for non-potable water reuse, and indicated that integrated planning toward a multiple source approach could provide best outcomes for the achievement of a water sensitive city. Shela (2000) has provided a good insight of water management of shared river basins through providing management strategy covering territories of Angola, Botswana, Malawi, Mozambique, Namibia, Tanzania, Zambia, and Zimbabwe.
At the end of 2015, the rainy season presented average precipitation levels in the Brazilian southeastern region and the Water Crisis was finally over. However, the urban water planners neither evaluated the effectiveness of the CWRMP nor proposed its review, and new episodes of water scarcity are imminent. In the meantime, the sustainability issue also became prominent (Marques et al., 2015) and water resources management plans should always consider this factor for future water planning. In a holistic approach, ideally, all the factors including sustainability should be considered. However, this was not the scope of this study.
On 27 May 2021, the National Meteorological System (SNM, 2021) issued an emergency alert associated with the water scarcity for the hydrographic region of Paraná River Basin, which covers several states of Brazil, including São Paulo State, for the period between June and September of 2021. In regards to the current study area, three water emergency alerts have already been issued for the region of Campinas in 2021, causing a huge concern about water rationing and power outages in the industrial sector.
Acknowledging the adverse impacts of the Water Crisis and recognizing the possibility of occurring a new one, we emphasize the need for constant studies regarding long-term planning of water management, such as the CWRMP, in order to ensure the water security. Also, we point out that the water resources plans in Brazil (at the national, state, local, and basin levels) are often poorly coordinated or even not implemented (Brazil, 2017), which makes their effectiveness evaluation very important. Therefore, the aim of this study is to evaluate the effectiveness of the actions proposed in the CWRMP, in order to subsidize its future review and guide further studies.
This paper is organized as follows: Section ‘Study Area’ describes the area characteristics; Section ‘Methods’ presents the methodology used to evaluate the CWRMP guidelines, concerning the CWRMP considering four major actions; Section ‘Results and Discussion’ presents the results divided into four subsections, one for each action; and, the Conclusion is given in the last section.
STUDY AREA
This study was carried out in the municipality of Campinas, in the State of São Paulo, Brazil, located between latitudes 22°44′00″S and 23°04′00″S, and longitudes 46°48′00″W and 47°12′00″W (Figure 1). Campinas has approximately 1.20 million inhabitants, which 98.3% is in the urban area (IBGE, 2020). The total area of the study area is 795.4 km2, with elevations varying between 1.078 m (eastside) and 550 m (westside) (Figure 2(a)). Campinas has a dense streams network (Figure 2(b)), presenting three main rivers: Atibaia, Capivari, and Jaguari. The most important one is Atibaia, which supplies 95.0% of the water demand.
Location of the study area: municipality of Campinas, State of São Paulo, Brazil. Source: Authors.
Location of the study area: municipality of Campinas, State of São Paulo, Brazil. Source: Authors.
Campinas map of (a) elevation (USGS et al., 2013); (b) Streams network, main rivers and Campinas Water Extraction Point (CWEP) (DAEE, 2019; PMC, 2021); (c) Köppen climate classification (Alvares et al., 2013); and (d) Hydrological Soil Group (Coelho et al., 2005; Sartori et al., 2005).
Campinas map of (a) elevation (USGS et al., 2013); (b) Streams network, main rivers and Campinas Water Extraction Point (CWEP) (DAEE, 2019; PMC, 2021); (c) Köppen climate classification (Alvares et al., 2013); and (d) Hydrological Soil Group (Coelho et al., 2005; Sartori et al., 2005).
According to Köppen climate classification system, Campinas has a predominantly humid subtropical climate without a dry season with hot summer (Cfa) (Figure 2(c); Alvares et al., 2013). The eastside of Campinas, featured by higher altitudes, has a humid subtropical condition, undefined dry season, and higher temperature (i.e., summer weather) (Cfb). The average annual precipitation and temperature are 1,450 mm and 24.5 °C, respectively (PMC, 2016).
The predominant soils in Campinas are classified as type A (Figure 2(d)) of Hydrological Soil Group (HSG) classification (Coelho et al., 2005; Sartori et al., 2005). The HSG is a soil classification scheme from the lowest (type A) to the highest (type D) runoff potential developed by the National Resources Conservation Service (NRCS) (United States Department of Agriculture – USDA, 2009). The percentage of each HSG in Campinas is 45.6, 39.2, 11.8, and 3.3% to soil types A, B, C, and D, respectively.
Campinas has a population of 1,213,792 inhabitants, making it the 14th most populous Brazilian city and the third most populous municipality of the State of São Paulo. It has the third largest Gross Domestic Product (GDP) of the State of São Paulo, estimated in R$ 61.4 billion, based on services (67.1%), industry (15.2%), agribusiness (0.2%), and government taxes (17.5%) (SEADE, 2021). The city offers a wide range of services such as higher education in public and private entities, medical and hospital services, and an infrastructure network, such as Viracopos International Airport.
METHODS
Throughout the study, we assembled the guidelines of CWRMP regarding the water resources management into four major actions:
Action 1, increase the permeability rate and the soil infiltration capacity. These parameters affect the amount of water that enters a soil, and also the nutrients and pollutants dissolved in it (Kirkham, 2014), influencing the water supply quantitative and qualitatively.
Action 2, increase the vegetation cover, especially in riparian forests. These areas help to stabilize streambanks, preserving the balance of processes such as erosion and sedimentation (Salemi et al., 2012), and to retain sediment and chemicals, preventing the water quality from being negatively affected (Prinsloo & Scott, 1999).
Action 3, improve the sanitation services. These services include the water supply, sewage and waste collection networks, which affect the quantity and quality of the water resources.
Action 4, minimize the number of contaminated areas. These areas potentially increase the risk of groundwater contamination, which reduce the water availability that could be used in scarcity scenarios.
The methodological approach of this study was to evaluate the four actions of the CWRMP, as described in Table 1. Further information is presented subsequently.
Data parameterization and evaluation process of the CWRMP actions.
Action . | Data Parameterization and Evaluation Process . | |
---|---|---|
No. . | Purpose . | |
1 | Increase the permeability rate and the soil infiltration capacity | Acquisition of Landsat imagery from the United States Geological Survey (USGS) Earth Explorer. The imagery used was from years of 2001, 2016, and 2020. The period between 2001 and 2016 was used to analyze the natural tendency of urban growth and sprawl, whereas the period between 2016 and 2020 was used to evaluate CWRMP effectiveness. |
Imagery processing and classification of LULC (Water, Bare Soil, Urban, Forest, and Agriculture) by the use of the Geographic Information System (GIS) software ArcGIS 10.6 (ESRI, 2011), applying the Maximum-Likelihood supervised classification technique (ESRI, 2018). | ||
Assessment of the classification process accuracy by the Kappa Index (KI) calculation (Landis & Koch, 1977). The minimum KI value adopted was 0.80. | ||
Analysis of LULC maps over the studied periods. | ||
Estimation of the Curve Number (CN) values for Campinas using the LULC and HSG maps, and the NRCS-CN tables (USDA, 2004). | ||
Analysis of the CN values variation to evaluate the permeability changes over time in the study area. | ||
2 | Increase the vegetation cover, especially in riparian forests | Determination of the Forest class area changes by the use of the LULC maps. |
Evaluation of the riparian forest changes by the use of legal delimitation map of these areas (PMC, 2016). | ||
Analysis of the Forest class variation in the riparian forest. | ||
3 | Improve the sanitation services | Evaluation of the historical series of sanitation services indexes, obtained from SNIS, the Brazilian National Sanitation Database (SNS, 2021), which included water supply, sewage coverage, and waste collection. |
4 | Minimize the number of contaminated areas | Analysis of the evolution of contaminated areas between 2016 and 2020, according to the approach and database of the Environmental Company of the State of São Paulo (CETESB, 2019). |
Action . | Data Parameterization and Evaluation Process . | |
---|---|---|
No. . | Purpose . | |
1 | Increase the permeability rate and the soil infiltration capacity | Acquisition of Landsat imagery from the United States Geological Survey (USGS) Earth Explorer. The imagery used was from years of 2001, 2016, and 2020. The period between 2001 and 2016 was used to analyze the natural tendency of urban growth and sprawl, whereas the period between 2016 and 2020 was used to evaluate CWRMP effectiveness. |
Imagery processing and classification of LULC (Water, Bare Soil, Urban, Forest, and Agriculture) by the use of the Geographic Information System (GIS) software ArcGIS 10.6 (ESRI, 2011), applying the Maximum-Likelihood supervised classification technique (ESRI, 2018). | ||
Assessment of the classification process accuracy by the Kappa Index (KI) calculation (Landis & Koch, 1977). The minimum KI value adopted was 0.80. | ||
Analysis of LULC maps over the studied periods. | ||
Estimation of the Curve Number (CN) values for Campinas using the LULC and HSG maps, and the NRCS-CN tables (USDA, 2004). | ||
Analysis of the CN values variation to evaluate the permeability changes over time in the study area. | ||
2 | Increase the vegetation cover, especially in riparian forests | Determination of the Forest class area changes by the use of the LULC maps. |
Evaluation of the riparian forest changes by the use of legal delimitation map of these areas (PMC, 2016). | ||
Analysis of the Forest class variation in the riparian forest. | ||
3 | Improve the sanitation services | Evaluation of the historical series of sanitation services indexes, obtained from SNIS, the Brazilian National Sanitation Database (SNS, 2021), which included water supply, sewage coverage, and waste collection. |
4 | Minimize the number of contaminated areas | Analysis of the evolution of contaminated areas between 2016 and 2020, according to the approach and database of the Environmental Company of the State of São Paulo (CETESB, 2019). |
To evaluate Action 1, we used the CN parameter. The CN is the most important parameter of the NRCS-CN model to estimate the rainfall-runoff behavior of a basin. According to Hawkins et al. (2009), the CN parameter is based on the analysis of the LULC, HSG, and Antecedent Runoff Condition (ARC). The ARC attempts to assemble some aspects that may cause the CN variability, such as the rainfall intensity and duration, total rainfall, soil moisture conditions, vegetation cover, vegetation growth stage, and temperature (USDA, 2004). The ARC is divided into three classes: II (for average conditions), I (for dry conditions), and III (for wet conditions). The NRCS provides tables with suggested CN values for different LULC and HSG considering ARC II. The CN parameter varies between 0 and 100 and higher values indicate a higher runoff potential temperature (USDA, 2004). Thus, the increase of CN values indicates a decrease in terms of pervious areas and/or soil infiltration capacity (Boulomytis et al., 2016).
The CN value for the study area was calculated by the mean of CN values (Table 2) weighted by its corresponding percentage area. We compared the CN values for 2001, 2016, and 2020 to evaluate the permeability changes over the studied period.
CN values for each LULC class and HSG of the study area.
LULC class . | Hydrologic Soil Group . | |||
---|---|---|---|---|
A . | B . | C . | D . | |
Water | 98 | 98 | 98 | 98 |
Bare Soil | 77 | 86 | 91 | 94 |
Urban | 89 | 92 | 94 | 95 |
Forest | 30 | 55 | 70 | 77 |
Agriculture | 65 | 75 | 82 | 86 |
LULC class . | Hydrologic Soil Group . | |||
---|---|---|---|---|
A . | B . | C . | D . | |
Water | 98 | 98 | 98 | 98 |
Bare Soil | 77 | 86 | 91 | 94 |
Urban | 89 | 92 | 94 | 95 |
Forest | 30 | 55 | 70 | 77 |
Agriculture | 65 | 75 | 82 | 86 |
Regarding the sanitation services (Action 3), we analyzed the data from the SNIS, which is the largest and more important database of the Brazilian sanitation sector, gathering 185 data about operational, managerial, financial, and quality sanitation services to produce 84 indexes (SNS, 2021). We chose 7 indexes to evaluate the sanitation services of our study area, which are presented in Table 3. One of the limitations regarding the water consumption per capita analysis is that about 60% of the underground water exploitation of the basin is not legally registered and has no use permit (Hirata, 2018). Thus, it is not possible to estimate the undergraduate water consumption, as the real collected volume is not measured.
Sanitation service indexes used for the study area.
Index . | Name . | Description . | Unit . |
---|---|---|---|
WT-1 | Urban water supply service coverage | Percentage of the urban population served by public water supply | % |
WT-2 | Water consumption per capita | Average daily water consumption of urban population | ![]() |
WT-3 | Water distribution losses | Percentage of losses in the water supply network | % |
SW-1 | Sewage service coverage | Percentage of the urban population served by public sewage collection service | % |
SW-2 | Sewage treatment index | Percentage of the urban collected sewage which is treated | % |
WC-1 | Waste collection service coverage | Percentage of the urban population served by waste collection | % |
WR-1 | Waste recycling service coverage | Percentage of the urban population served by waste recycling | % |
Index . | Name . | Description . | Unit . |
---|---|---|---|
WT-1 | Urban water supply service coverage | Percentage of the urban population served by public water supply | % |
WT-2 | Water consumption per capita | Average daily water consumption of urban population | ![]() |
WT-3 | Water distribution losses | Percentage of losses in the water supply network | % |
SW-1 | Sewage service coverage | Percentage of the urban population served by public sewage collection service | % |
SW-2 | Sewage treatment index | Percentage of the urban collected sewage which is treated | % |
WC-1 | Waste collection service coverage | Percentage of the urban population served by waste collection | % |
WR-1 | Waste recycling service coverage | Percentage of the urban population served by waste recycling | % |
WT, water; SW, sewage; WC, waste collection; WR, waste recycling.
Source: SNS (2021).
In order to evaluate the Action 4, we used the classification of contaminated areas (Table 4) proposed by CETESB (2019), which is the public agency responsible for the inspection and management of contaminated areas in the State of São Paulo.
Classification of contaminated areas.
Code . | Description . | Classification . |
---|---|---|
CAUI | Contaminated Area Under Investigation | Area where contaminant concentrations were found by means of confirmatory investigation and (may) endanger the assets to be protected. |
CACR | Contaminated Area under Confirmed Risk | Area where the soil or groundwater contamination has been confirmed, through detailed investigation and risk assessments, causing potential risks to the environment and human health or where the legal contamination limits have been exceeded. |
CARP | Contaminated Area under a Remediation Process | Area where remediation measures are currently being applied to remove contaminants, or, in the case of absence of technical or economic feasibility, to reduce or hold the levels of contamination. |
CARe | Contaminated Area in Reuse Process | Contaminated area where a new soil use is intended, eliminating the contaminants, or reducing them to acceptable levels. |
APMC | Area in Process of Monitoring for Closure | Area in which no risk was detected, or the remediation process was finished, and is being monitored to verify the maintenance of acceptable contaminant concentration levels. |
RADU | Rehabilitated Area for Declared Use | Previously contaminated area which use was restored after remediation measures, which reduced the contaminants to acceptable levels, even if they were not completely eliminated. |
CrCA | Critical Contaminated Area | Contaminated area that offers imminent risk to human life or health and requires immediate intervention by the authorities. This area demands a distinguished implementation, risk communication, and information management. |
Code . | Description . | Classification . |
---|---|---|
CAUI | Contaminated Area Under Investigation | Area where contaminant concentrations were found by means of confirmatory investigation and (may) endanger the assets to be protected. |
CACR | Contaminated Area under Confirmed Risk | Area where the soil or groundwater contamination has been confirmed, through detailed investigation and risk assessments, causing potential risks to the environment and human health or where the legal contamination limits have been exceeded. |
CARP | Contaminated Area under a Remediation Process | Area where remediation measures are currently being applied to remove contaminants, or, in the case of absence of technical or economic feasibility, to reduce or hold the levels of contamination. |
CARe | Contaminated Area in Reuse Process | Contaminated area where a new soil use is intended, eliminating the contaminants, or reducing them to acceptable levels. |
APMC | Area in Process of Monitoring for Closure | Area in which no risk was detected, or the remediation process was finished, and is being monitored to verify the maintenance of acceptable contaminant concentration levels. |
RADU | Rehabilitated Area for Declared Use | Previously contaminated area which use was restored after remediation measures, which reduced the contaminants to acceptable levels, even if they were not completely eliminated. |
CrCA | Critical Contaminated Area | Contaminated area that offers imminent risk to human life or health and requires immediate intervention by the authorities. This area demands a distinguished implementation, risk communication, and information management. |
Source: CETESB (2019).
RESULTS AND DISCUSSION
Action 1
For the evaluation of Action 1, we processed three Landsat images located in the same coordinates (path 219 and row 76): one Landsat 7 ETM+ image was achieved on 03 May 2001, and the other two were Landsat 8 OLI/TIRS images, achieved on 07 July 2016 and 31 May 2020, respectively. The imagery was used to identify the LULC changes before (2001–2016) and after the implementation of the CWRP (2016–2020). The LULC class areas and the KI values are presented in Table 5 and shown in Figure 3.
The LULC class, area, and KI values for the classified Landsat imagery.
Class . | Area (km2) . | Area (%) . | ||||
---|---|---|---|---|---|---|
2001 . | 2016 . | 2020 . | 2001 . | 2016 . | 2020 . | |
Water | 0.84 | 0.91 | 0.63 | 0.11 | 0.11 | 0.08 |
Bare Soil | 77.72 | 21.09 | 37.05 | 9.77 | 2.65 | 4.66 |
Urban | 214.57 | 243.65 | 249.38 | 26.98 | 30.63 | 31.36 |
Forest | 51.27 | 63.32 | 72.76 | 6.45 | 7.96 | 9.15 |
Agriculture | 451.02 | 466.38 | 435.52 | 56.70 | 58.64 | 54.76 |
Kappa Index | 0.85 | 0.86 | 0.84 | – | – | – |
Class . | Area (km2) . | Area (%) . | ||||
---|---|---|---|---|---|---|
2001 . | 2016 . | 2020 . | 2001 . | 2016 . | 2020 . | |
Water | 0.84 | 0.91 | 0.63 | 0.11 | 0.11 | 0.08 |
Bare Soil | 77.72 | 21.09 | 37.05 | 9.77 | 2.65 | 4.66 |
Urban | 214.57 | 243.65 | 249.38 | 26.98 | 30.63 | 31.36 |
Forest | 51.27 | 63.32 | 72.76 | 6.45 | 7.96 | 9.15 |
Agriculture | 451.02 | 466.38 | 435.52 | 56.70 | 58.64 | 54.76 |
Kappa Index | 0.85 | 0.86 | 0.84 | – | – | – |
We observed a slight absolute variation of the Water class (total reduction of 0.21 km2). Since the water levels may vary due to several factors, such as rainfall occurrence or water use, we do not consider it a significant change.
The Bare Soil class presented a significant variation over the studied period. This class covered almost 10.0% of Campinas area in 2001, was reduced to 2.7% in 2016, and increased in 2020 to 4.7%. The Bare Soil class is considered a transition among the different LULC classes, especially the Urban and Agriculture classes, which explains the observed behavior. Near urban areas, the Bare Soil class might be the land clearing prior to construction, whereas in agricultural areas, for instance, it might be the intermediate stage between the harvesting and the preparation for the next crop. The evaluation of this class is challenging for land and water managers, especially regarding the validity of its estimation.
The Urban area class expanded 34.80 km2 in the analyzed period, with its spatial distribution presented in Figure 4(a). We observed a reduction of the urbanization process rate, possibly due to the CWRMP enactment. Between 2001 and 2016, the urban area had increased by 29.10 km2, corresponding to a rate of 1.82 km2/year, and, after the CWRMP enactment, it increased by 5.70 km2, which comprises to a rate of 1.15 km2/year. Spatially, we verified an expansion of this class concentrated on the Campinas western side, which confirms the expansion pattern already observed by Hammann (2011) for the period between 1989 and 2010. We also observed that there was an increase of small urban occupations in other regions. This urban sprawl could represent a poor accessibility to goods and services for the population of these new areas, as it increases the dependence on means of transportation due to the longer distance from the business center and requires a sprawled infrastructure extension (Hamidi et al., 2015).
Campinas map of (a) spatial distribution of Urban LULC class over time; (b) spatial distribution of Forest LULC class over time (Source: PMC (2021)); (c) spatial distribution of Riparian Forests over time and its theoretical distribution (Source: PMC (2021)); and (d) Campinas contaminated areas in 2019 (according to Table 4) (Source: CETESB (2019)).
Campinas map of (a) spatial distribution of Urban LULC class over time; (b) spatial distribution of Forest LULC class over time (Source: PMC (2021)); (c) spatial distribution of Riparian Forests over time and its theoretical distribution (Source: PMC (2021)); and (d) Campinas contaminated areas in 2019 (according to Table 4) (Source: CETESB (2019)).
The Forest class presented an expansion of 12.10 km2 from 2001 to 2016, and of 9.40 km2 from 2016 to 2020, which represents the rates of 0.75 and 1.89 km2/year, respectively. This behavior could be explained, for both studied periods, by the enactment of some municipal environmental laws, highlighting the Municipal Law n. 10.850/2001 (PMC, 2001), which implemented the Environmental Protection Area of Campinas (APA Campinas). The APA Campinas is located between Atibaia and Jaguari Rivers in the eastern side of Campinas and covers almost one third of the municipality (223 km2) (Figure 4(b)). The increase in the Forest class expansion rate from 0.75 km2/year in the first period to 1.89 km2/year in the second period may be due to the plans and programs proposed by CWRMP in 2016, which reinforced the environmental commitment of Campinas to forest restoration.
The Agriculture class presented an increase of 15.4 km2 (between 2001 and 2016) and a reduction of 30.9 km2 (between 2016 and 2020). As mentioned above, the Bare Soil class is considered a transition among the different LULC classes, including the Agriculture class, which may present seasonal planting. Therefore, the agriculture area variability could be explained by the variations of the Bare Soil class once they may be considered interchangeable. Despite this reduction, the Agriculture class remains with the major LULC area, representing 54.8% of the current LULC of the municipality. As a result, Campinas has a varied agricultural production, such as sugarcane, fruits, vegetables, and livestock (PMC, 2015). Thus, the correct management of these areas is essential to avoid environmental impacts, such as the erosion process or soil contamination (e.g., exceeding loads of nitrate), as well as to reduce social conflicts by the water use in scarcity scenarios.
The LULC and the HSG maps were used to estimate the CN parameter over the studied period as an indicator of the soil permeability, the Action 1 main purpose. The estimated CN values for Campinas were 77, 75, and 74, for 2001, 2016, and 2020, respectively.
We observed a reduction of the CN values throughout the whole studied period, indicating that the area of Campinas is more pervious than before. Furthermore, the reduction rate has increased from 0.13 units of CN per year between 2001 and 2016 to 0.25 units of CN per year between 2016 and 2020, which may be a consequence of the CWRMP enactment. Despite the small absolute decrease of CN value, we emphasize the importance of this reduction since a unit of CN has a great impact in the direct runoff prediction in the NRCS-CN model (Hawkins et al., 2009).
We observed an increase of 34.81 and 21.49 km2 in the Urban and the Forest class areas between 2001 and 2020 (Figure 3), respectively. Despite the greater increase of the former class, the estimated CN value has decreased. We explain this behavior by the analysis of Table 2, where the CN recommended values for Forest class are much lower than the other ones. Thus, any LULC change to the Forest class results in a greater impact on the estimated CN value than a change to the Urban class.
The expansion of the Forest class reflects a positive effect of the CWRMP implementation. This class has a higher permeability rate and soil infiltration capacity than the other LULC classes (Zimmermann et al., 2006). Hence, we emphasize the importance of laws that improve policies for the conservation and restoration of environmental resources.
Action 2
The Action 2 is composed by the analysis of the vegetation cover changes in the whole studied area and especially in the riparian forests. The analysis in the area of Campinas was discussed above, as a part of Action 1, and in the riparian forests is presented as follows.
According to PMC (2021), the riparian forests of Campinas occupy an area of approximately 165 km2 (Figure 4(c)), concentrated in the eastern side, where the APA Campinas is located (Figure 4(b)), and the drainage density is higher (Figure 2(b)).
The riparian forests of Campinas presented 17.77, 23.22, and 30.08 km2 of the Forest class in 2001, 2016, and 2020, respectively, which represents an increase rate of 0.36 km2/year in the first period, and 1.72 km2/year in the last one. These values prove that the CWRMP enactment has been effective to the riparian forest restoration, which is the purpose of Action 2.
Action 3
Regarding the evaluation of Action 3, the sanitation data was obtained from SNS (2021) and is presented in Table 6.
Sanitation indexes of Campinas.
Year . | WT-1 . | WT-2 . | WT-3 . | SW-1 . | SW-2 . | WC-1 . | WR-1 . |
---|---|---|---|---|---|---|---|
2001 | 98.0 | 219.5 | 26.4 | 87.0 | 8.5 | – | – |
2002 | 98.4 | 218.8 | 25.6 | 88.4 | 9.8 | – | – |
2003 | 99.6 | 209.6 | 26.9 | 89.4 | 10.6 | – | – |
2004 | 97.8 | 202.0 | 27.1 | 87.2 | 17.1 | – | – |
2005 | 96.8 | 208.1 | 25.8 | 85.2 | 29.3 | – | – |
2006 | 96.6 | 210.3 | 25.8 | 86.8 | 32.3 | – | – |
2007 | 99.7 | 210.8 | 24.2 | 89.5 | 44.9 | – | – |
2008 | 99.2 | 207.4 | 21.8 | 89.1 | 62.5 | – | – |
2009 | 99.6 | 209.2 | 20.2 | 88.4 | 65.3 | 100 | – |
2010 | 98.8 | – | – | – | – | 100 | – |
2011 | 98.0 | 218.7 | 19.9 | 85.0 | 73.4 | 98.0 | – |
2012 | 99.5 | 224.1 | 19.3 | 88.3 | 78.7 | 100 | 75.0 |
2013 | 99.5 | 218.3 | 19.2 | 88.2 | 78.9 | 100 | 75.0 |
2014 | 99.5 | 198.5 | 21.6 | 89.2 | 81.1 | 100 | 75.0 |
2015 | 99.5 | 181.4 | 20.8 | 92.5 | 86.3 | 100 | 75.0 |
2016 | 99.6 | 186.1 | 21.6 | 92.5 | 86.4 | 100 | 75.0 |
2017 | 99.8 | 184.1 | 20.9 | 95.7 | 86.8 | 100 | 75.0 |
2018 | 99.8 | 182.8 | 20.8 | 96.1 | 88.4 | 100 | 76.3 |
2019 | 99.8 | 186.0 | 20.7 | 96.3 | 89.3 | 100 | 76.3 |
Year . | WT-1 . | WT-2 . | WT-3 . | SW-1 . | SW-2 . | WC-1 . | WR-1 . |
---|---|---|---|---|---|---|---|
2001 | 98.0 | 219.5 | 26.4 | 87.0 | 8.5 | – | – |
2002 | 98.4 | 218.8 | 25.6 | 88.4 | 9.8 | – | – |
2003 | 99.6 | 209.6 | 26.9 | 89.4 | 10.6 | – | – |
2004 | 97.8 | 202.0 | 27.1 | 87.2 | 17.1 | – | – |
2005 | 96.8 | 208.1 | 25.8 | 85.2 | 29.3 | – | – |
2006 | 96.6 | 210.3 | 25.8 | 86.8 | 32.3 | – | – |
2007 | 99.7 | 210.8 | 24.2 | 89.5 | 44.9 | – | – |
2008 | 99.2 | 207.4 | 21.8 | 89.1 | 62.5 | – | – |
2009 | 99.6 | 209.2 | 20.2 | 88.4 | 65.3 | 100 | – |
2010 | 98.8 | – | – | – | – | 100 | – |
2011 | 98.0 | 218.7 | 19.9 | 85.0 | 73.4 | 98.0 | – |
2012 | 99.5 | 224.1 | 19.3 | 88.3 | 78.7 | 100 | 75.0 |
2013 | 99.5 | 218.3 | 19.2 | 88.2 | 78.9 | 100 | 75.0 |
2014 | 99.5 | 198.5 | 21.6 | 89.2 | 81.1 | 100 | 75.0 |
2015 | 99.5 | 181.4 | 20.8 | 92.5 | 86.3 | 100 | 75.0 |
2016 | 99.6 | 186.1 | 21.6 | 92.5 | 86.4 | 100 | 75.0 |
2017 | 99.8 | 184.1 | 20.9 | 95.7 | 86.8 | 100 | 75.0 |
2018 | 99.8 | 182.8 | 20.8 | 96.1 | 88.4 | 100 | 76.3 |
2019 | 99.8 | 186.0 | 20.7 | 96.3 | 89.3 | 100 | 76.3 |
Source: SNS (2021).
The WT-1 index did not present noteworthy fluctuations, indicating that Campinas has always had public water supply service available for the majority of the population. The WT-2 index reflects the population water consumption habits. Between 2001 and 2013, the average water demand per capita was 213.1 L/day and, after the Water Crisis and the CWRMP enactment, this value was reduced to 186.5 L/day, comprising a decrease of 12.5%. Thus, we attribute this behavior change to the adverse hydrological conditions, and the environmental education programs carried out in Campinas.
The WT-3 index presents a slight reduction of water loss in the water supply network of Campinas between 2006 and 2013 and assumed a nearly constant value afterwards. Therefore, the CWRMP, which was enacted in 2016, did not significantly affect the index. For a comparison purpose, the National Sanitation Plan sets the goal of reducing losses in the Brazilian Southeast region to 32.0% in 2023 (Brazil, 2019). Thus, the WT-3 values for Campinas are satisfactory, regardless of the CWRMP enactment, and reflect the effort developed by SANASA to repair and maintain the operational conditions of the water supply network.
Similar to WT-1, the SW-1 did not present noteworthy fluctuations, indicating that Campinas has always had public sewage collection available for the majority of the population. We point out that there is a small difference between the WT-1 and SW-1 values, which has been smoothly reduced over the last 10 years. Besides the sewage network expansion, we observed an accelerated increase of the percentage of sewage treatment (SW-2), from 8.5 to 89.3% during the whole period studied. This situation contrasts with the national framework once Brazil still has low sewage collection and treatment rates, corresponding to 54.1 and 49.1%, respectively (Brazil, 2019).
Therefore, the joint analysis of the Water and Sewage indexes evidences the efforts of SANASA to universalize the sanitation services in Campinas, regardless of the CWRMP enactment. We point out that, from January 2013 to December 2015, SANASA had invested almost R$ 348 million (Brazilian currency) in these services, and, since 2015, SANASA has expanded the replacement of water networks from 70 to 140 km per year (SANASA, 2016).
The solid waste and selective solid waste collection services did not present significant changes over the available data period, as observed in WC-1 and WR-1 indexes values. Thus, we can state that Campinas has a door-to-door waste collection that has served the households during the entire period of the study, even when the urban areas has increased. However, we did not observe an increase of recycling waste collection despite the CWRMP enactment. Thus, we recommend the expansion of the selective waste collection service, in order to reach the totality of the urban population. Besides, we suggest actions of environmental education to make the Campinas population aware of the importance of recycling and the correct waste disposal.
In summary, we observed that the local sanitation indexes are, in general, satisfactory in the analyzed period, regardless of the CWRMP enactment, pointing out the continuous efforts developed by the local government along with SANASA to improve Campinas sanitation conditions.
Action 4
The Campinas contaminated areas data is summarized in Table 7. The georeferenced data is only available for 2018 and 2019, because the data prior to 2018 was reported in analogical media and has not been fully transferred to digital media yet.
Relationship of Campinas Contaminated Areas.
Year . | Classification . | |||||||
---|---|---|---|---|---|---|---|---|
CAUI . | CACR . | CARP . | CARe . | APMC . | RADU . | CrCA . | Total . | |
2018 | 33 | 21 | 34 | 5 | 33 | 42 | 0 | 168 |
2019 | 30 | 17 | 32 | 5 | 31 | 54 | 0 | 169 |
Year . | Classification . | |||||||
---|---|---|---|---|---|---|---|---|
CAUI . | CACR . | CARP . | CARe . | APMC . | RADU . | CrCA . | Total . | |
2018 | 33 | 21 | 34 | 5 | 33 | 42 | 0 | 168 |
2019 | 30 | 17 | 32 | 5 | 31 | 54 | 0 | 169 |
Source: CETESB (2019).
The spatial distribution of Campinas contaminated areas is illustrated in Figure 4(d), concentrated in urban areas (Figure 4(a)). The main economic activity in these areas corresponds to gas stations and related services (107 occurrences), which explains the urban concentration once this economic activity is located in areas with high traffic. Furthermore, the available data did not present any contaminated areas in the eastern portion of the municipality, where APA Campinas is located, which indicates an adequate soil management practice by the local government, reducing the spread of this environmental problem.
We observed that many contaminated areas were recovered in Campinas, once the areas classified as CAUI, CACR, CARP, and APMC have summed a reduction of 11 units and RADU had increased 12 units in the studied period. These recovered areas may be used again for anthropic and economic activities, improving the quality of life and reducing the risk of soil and groundwater contamination.
CONCLUSION
In the present study, we assembled and evaluated the guidelines of the CWRMP based on four actions. Action 1 showed a decrease of Campinas CN number, whereas Action 2 presented an increase of Riparian Forests. These actions result in an improvement of Campinas permeability rate and its soil infiltration capacity, increasing the amount and the quality of water that enters in groundwater system. Action 3 reveals the efforts made by SANASA to offer and improve the sanitation services, reducing pressures exerted in Campinas water resources. A significant number of contaminated areas were recovered in Campinas during the studied period, regarding to Action 4.
We concluded that the CWRMP may be considered a valuable initiative toward the improvement of water resources management in Campinas. The plan has already achieved significant beneficial results, along with actions performed by SANASA, CETESB, and other governmental agencies, highlighting the advantages of the cooperation among these institutions.
For the enhancement of the CWRMP implementation, we recommend the Campinas government to create a public and readily available database to assemble the existing data that may be applied for new studies in the area and continuously update it. Finally, we also suggest the application of modeling tools to expand the analysis in the future studies, optimizing the data use and providing more information to subsidize the decision-making process by the city planners.
CONFLICT OF INTEREST
The authors declare none.
DATA AVAILABILITY STATEMENT
All relevant data are included in the paper or its Supplementary Information.