**2.1 Relief, hydrography, and vegetable coverage**

The Rodrigo de Freitas Lagoon is situated in the southern zone of the city of Rio de Janeiro, between two mountains (Sumare and Corcovado) and the seafront of Ipanema, and is also bordered by the districts of Humaita and Gavea. With an area of 32 km2 , its drainage basin covers a large part of the districts of Gavea, Jardim Botânico (the Botanical Gardens), Ipanema, and Leblon, including the Lagoon, which necessarily serves as a storage basin in the periods of heaviest rainfall. The LRF has a water feature of about 2.2 km<sup>2</sup> , a perimeter of 7.8 km, and an average depth of the order of 2.80 m, with a maximum of 4.0 m and a volume of approximately 6,200,000 m3 [6]. It was noted that after the sand removal works that were carried out on the bed of the Lagoon during the period preceding the Olympic Games in 2016, some parts showed a greater depth than 4.0 m.

The LRF is replenished by the rivers that flow down from the surrounding slopes and currently this water is salubrious. The main rivers concerned are the Rios dos Macacos e Cabeca (Rivers of the Monkeys and Head) which flow into the Lagoon through the Rua (Street) General Garzon Canal and River Rainha (Queen), which is currently being diverted by the Avenida Visconde de Albuquerque Canal (**Table 1**) [7].

The interconnection of the Lagoon with the sea is being effected by the Jardim de Alah, a man-made canal which is 800 m long and has a width which ranges between 10 and 18 m, although one section of its depth is 0.70 m (**Figure 1**). The RIOAGUAS Foundation is responsible for controlling the level of the water feature of the Lagoon by operating the sluices in the canals of the Jardim de Alah, from Visconde de Albuquerque and General Garzon, with a view to improving the environmental conditions of the LRF and the bathing in the Ipanema and Leblon beaches.

TECMA (Environmental Technology) [8] states that it is essential to take note of the rivers and canals linked to the Rodrigo de Freitas Lagoon to obtain a full understanding of its complexity, insofar as any alteration in the quality or volume of the inflow system can affect the dynamics of these waters.

Serious flooding has been recorded in the region, especially in the less steep areas of the basin that are closest to the water feature of the Lagoon—such as in J. Botanico. This occurs during periods of heavy rainfall, together with a rise in the water level of the LRF. At these times, the floodgates of the Jardim de Alah Canal are opened, to allow the outflow of water to the sea, as well as the floodgates of the General Garzon Canal, with the aim of preventing the overflow of the water of this canal and hence extensive flooding in the surrounding area. However, this management of the sluices of CGG is only undertaken as a secondary strategy when the outflow of the water to the sea through the floodgates of the Visconde de Albuquerque Canal is not a sufficient response to the crisis [11].

*Lagoon Environments Around the World - A Scientific Perspective*

city and famous for its landscapes.

causing any subsequent problems.

the huge fish mortality rate.

such as sewage systems and urban drainage.

for walking, and a cycle track; in effect, it is one of the main tourist centers in the

The LRF has been suffering from the environmental effects of anthropic activities which have been practiced for decades, including the inputs of organic matter responsible for phenomena such as the constant eutrophication of the water bodies [1]. Rosso [2] suggests that the main culprits of the problems that have been detected are the intense urban occupation of the hydrographic basin, together with the growth of anthropic activities and a lack of compliance with elementary standards of urbanism or the basic regulations for environmental sanitary conditions

In view of its importance, the LRF has become a frequent target of controversy with regard to the quality of its water. More recently, the Lagoon has given way to speculation about whether it could be safely used for the rowing and canoeing events in the Olympic Games, in a way that would not put the competitors at risk. However, after a period of delay and heated debate with specialists being consulted and other interventionary measures, the events went ahead as planned without

The LRF has attracted a good deal of concern because of its valuable socioeconomic and environmental attributes and its great exposure in the national and international media with regard to the quality of its waters. The Lagoon is widely used by the public, and this includes recreational activities of a secondary kind or, in other words, activities in which contact with the water is sporadic or accidental and there is little likelihood of ingesting it. It is also used by traditional fishermen

As in the case of Fonseca and Santoro [3], as well as other lagoons along the coast of the State of Rio de Janeiro, the LRF has aroused interest among academics owing to the extent to which it has undergone adverse natural phenomena such as stagnation and the deterioration of the quality of its water, the release of gases, silting, and

The poor circulation and renewal of the waters of the Lagoon mean that the seawater which enters in small quantities and at a slow speed in its depths—where it is more dense—becomes anaerobic in a short time and full of gases, and this is further aggravated by the oxidation of the already present organic matter [4, 5]. The existence of natural barriers like Piraque Island, on the east shore, and Caicaras Island, on the south shore, underlines the difficulty faced by the Lagoon in being regularly replenished by the affluent rivers and the entry of water from the sea.

Several interventions have been made, in particular over the past few years, with a view to improving the environmental conditions of the Lagoon. These include the following: (a) a greater degree of surveillance with regard to the construction and irregular waste disposal in the sewers and drainage system, (b) the improvement of the alteration and renewal of the waters by adhering to stricter standards, and (c) forging a better link with the sea through the Jardim de Alah (Garden of Allah) Canal and its respective floodgate. A comprehensive environmental monitoring system was also installed which was based on frequent analyses of various physicochemical and bacteriological parameters at strategic points placed along the Lagoon; this formed a solid database for the support of decision-making, as well as

The objective of this research study is to analyze the data from the environmental monitoring which was carried out in the LRF. The purpose of this is to determine the conditions of the quality of the water that is not in compliance with the regulatory standards, as well as the failure to adhere to these parameters, especially with regard to the limits of CONAMA 357/05. On the basis of this analysis, the aim is to relate these failures to the occurrence of environmental degradation and anthropic activities, as well as the

the management and planning of preventive and control measures.

whose subsistence has depended on it for many generations.

**24**


#### **Table 1.**

*Features of the hydrographic basin of the Rodrigo de Freitas Lagoon [9].*

#### **Figure 1.**

*Connection of the Lagoon with the sea through the Jardim de Alah Canal [10].*

#### **2.2 Population and socioeconomic factors**

The LRF lies within the borough of the Lagoon and is situated in a region with a community that has a high purchasing power, with the exception of some local people who have informal occupations and whose houses lack a separate drainage system. Three of these areas are well known and stand out: (i) the irregular occupation in the area located at the end of the Rua Pacheco Leao, alongside the Jardim Botânico; (ii) the housing complex called Cruzada Sao Sebastiao, situated close to the Jardim de Alah; and (iii) the community in the area situated at the end of Rua Viuva Lacerda, near to Rua Humaita, in the district with the same name.

Soares et al. [1] provide the census for 2000 which showed that the population consisted of 18,221 inhabitants with 6652 households, while in 2010 this had risen to 21,198 inhabitants and 9361 households (when restricted to the area surrounding the Lagoon). The data provided by IPPUR and IBGE [12] suggest that the region (Macrozona VI-Lagoon) has a demographic density of 119.18 inhab/ha, which corresponds to 2.97% of the total population of the municipality.

**27**

*Environmental Monitoring of Water Quality as a Planning and Management Tool: A Case…*

**Feature Data Source**

Perimeter (km) 7.8 INEA [6] Average depth (m) 2.80 INEA [6]

Districts Ipanema, Leblon, Gávea, J. Botânico,

) 32 INEA [6]

) 2.2 INEA [6]

Humaitá e Lagoa

RIO DE JANEIRO [10]

18,221/6,652 Soares et al. [1]

21,198/9,361 Soares et al. [1]

2.97% IPPUR and IBGE [11]

) 6,200,000 INEA [6]

According to the data provided by SEBRAE [13], based on figures published by IBGE, the IDHM of the region ranges from 0.959 (Lagoon) to 0.970 (Ipanema), which are situated at the two highest points in the municipality. This represents a highly valued region of the city with high-rise buildings of a good standard, diversified trading practices, services, and leisure activities, including the shoreline of the Lagoon which is provided with clubs, beaches, bars, beach huts, and various tourist activities. According to the portal of RioTur [14], some of the most expensive buildings in Rio can be found in this region: in its ranking in the real estate market, the district is second only to Leblon. RioTur also states that at weekends, the three parks that encircle the picture postcard panorama—Patins, Taboas, and Cantagalo–are visited by 120,000 people in search of leisure and relaxation, where they are served by 15 food bars. **Table 2** shows some general features of

IDHM 0.959–0.970 SEBRAE [12]

Demographic density (inhab/ha) 111.18 IPPUR and IBGE [11]

The layout for the occupation of the region can basically be divided into three separate typologies. The first are areas with little or no occupation and linked to regions that are densely forested with steep slopes and form a part of (or are close to) the Forest of Tijuca. These places are difficult to reach, and the construction of allotments and new buildings is impeded by the environmental conditions of the area. There are some large areas with good vegetable coverage such as Parque Lage

The second typology for land use is linked to a large area of low occupation and includes areas of social interaction and recreation such as the numerous squares (Santos Dumont Square and others), the waterfront of the Lagoon (Patins and Catacumba Parks), as well as the extensive area of Gavea and Hipica Racecourse. The third typology encompasses the buildings (including various commercial and residential properties), shopping centers, schools, public roads, and sidewalks where the degree of urbanization and waterproofing protection is much greater

*DOI: http://dx.doi.org/10.5772/intechopen.88687*

Drainage basin área (km2

Population (inhab/number of households in 2000)

Population (inhab/number of households in 2010)

% of total population of the municipality of RJ

*General data concerning the LRF and its surroundings.*

Water feature (km2

Volume (m3

**Table 2.**

the LRF and its surroundings.

**2.3 Use and occupation of the soil**

and Jardim Botânico that are nearby.

than in the first two typologies.

*Environmental Monitoring of Water Quality as a Planning and Management Tool: A Case… DOI: http://dx.doi.org/10.5772/intechopen.88687*


#### **Table 2.**

*Lagoon Environments Around the World - A Scientific Perspective*

*Features of the hydrographic basin of the Rodrigo de Freitas Lagoon [9].*

1.9 Flows from the foothills of Morro do Corcovado, in sections

7.2 Flows from the foothills of the Queimado Sumaré mountains,

4.3 Flows from the southern slopes of Serra da Carioca, with paths

of 520 m, and is drained in the Av. Lineu de Paula Machado Canal which in turn issues from Rio dos Macacos, on the stretch along the Rua Gal. Garzon

in sections of 520 m, and is diverted in its final stretch, from Rua Gal. Garzon to the Canal of the Jockey Club

of 680 m, and is drained into the da V. de Albuquerque Canal

**Hydrographic conditions Districts that** 

**have been drained**

Jardim Botânico

Alto da B. Vista, Horto e Botânico

Gávea

*Connection of the Lagoon with the sea through the Jardim de Alah Canal [10].*

The LRF lies within the borough of the Lagoon and is situated in a region with a community that has a high purchasing power, with the exception of some local people who have informal occupations and whose houses lack a separate drainage system. Three of these areas are well known and stand out: (i) the irregular occupation in the area located at the end of the Rua Pacheco Leao, alongside the Jardim Botânico; (ii) the housing complex called Cruzada Sao Sebastiao, situated close to the Jardim de Alah; and (iii) the community in the area situated at the end of Rua

Soares et al. [1] provide the census for 2000 which showed that the population consisted of 18,221 inhabitants with 6652 households, while in 2010 this had risen to 21,198 inhabitants and 9361 households (when restricted to the area surrounding the Lagoon). The data provided by IPPUR and IBGE [12] suggest that the region (Macrozona VI-Lagoon) has a demographic density of 119.18 inhab/ha, which corresponds to 2.97% of the total population of the municipality.

Viuva Lacerda, near to Rua Humaita, in the district with the same name.

**2.2 Population and socioeconomic factors**

**26**

**Figure 1.**

**Water course**

Rio Cabeça

Rio Macacos

Rio Rainha

**Table 1.**

**Drainage area (km²)**

*General data concerning the LRF and its surroundings.*

According to the data provided by SEBRAE [13], based on figures published by IBGE, the IDHM of the region ranges from 0.959 (Lagoon) to 0.970 (Ipanema), which are situated at the two highest points in the municipality. This represents a highly valued region of the city with high-rise buildings of a good standard, diversified trading practices, services, and leisure activities, including the shoreline of the Lagoon which is provided with clubs, beaches, bars, beach huts, and various tourist activities.

According to the portal of RioTur [14], some of the most expensive buildings in Rio can be found in this region: in its ranking in the real estate market, the district is second only to Leblon. RioTur also states that at weekends, the three parks that encircle the picture postcard panorama—Patins, Taboas, and Cantagalo–are visited by 120,000 people in search of leisure and relaxation, where they are served by 15 food bars. **Table 2** shows some general features of the LRF and its surroundings.

#### **2.3 Use and occupation of the soil**

The layout for the occupation of the region can basically be divided into three separate typologies. The first are areas with little or no occupation and linked to regions that are densely forested with steep slopes and form a part of (or are close to) the Forest of Tijuca. These places are difficult to reach, and the construction of allotments and new buildings is impeded by the environmental conditions of the area. There are some large areas with good vegetable coverage such as Parque Lage and Jardim Botânico that are nearby.

The second typology for land use is linked to a large area of low occupation and includes areas of social interaction and recreation such as the numerous squares (Santos Dumont Square and others), the waterfront of the Lagoon (Patins and Catacumba Parks), as well as the extensive area of Gavea and Hipica Racecourse.

The third typology encompasses the buildings (including various commercial and residential properties), shopping centers, schools, public roads, and sidewalks where the degree of urbanization and waterproofing protection is much greater than in the first two typologies.

Urban growth, particularly informal settlements, have aggravated the problem of organic matter being dragged to the Lagoon, which, owing to a lack of investment in sanitary sewage systems in the last 30 years, has led to a very serious situation with regard to the effects of drainage on the water body [7].
