Study sites

Study site 1

Brazil Upper Tiete River Basin, Sao Paulo, Brazil
In the beginning of the last century São Paulo was a city of 300,000 inhabitants and occupied 0.6 percent of the Upper Tietê River Basin area. It has since transformed into a megalopolis of almost 20 million inhabitants, occupying more than one third of the basin. Today, SPMR is one of the largest metropolitan areas in the world, with 39 municipalities and a complex mix of activities, including intensive industrial growth.With over 98% of its area already urbanized, the SPMR represents a great challenge in urban development, including water management. Unplanned and informal settlements present a great challenge, as well as the high demographic density in certain areas.

Industrialization and urban growth took place at the cost of greater production of sewage, and the need to look for water supply sources in neighboring watersheds away from the demand center. Water supply demands have grown exponentially and new water sources are becoming harder to find. The water supply utility (SABESP) for metropolitan area faces tremendous challenges both technical and financial in order to supply the growing demand.

Implementing water reuse and recycling schemes might help to alleviate the demand. Yet, even though such schemes have already been in place in the SPMR for some time, there is still no specific regulatory framework in place. Presently, existing regulations on water and wastewater management have been guiding these implementations. The uncertainty on the application of the existing regulatory framework hinders the development and implementation of new schemes of reuse and recycling technologies.

The potential for water reuse is very high in industrial uses. Urban reuse also presents a high potential, but this option would be more complex to implement, as there are a large number of consumers with low demand spread over an area of 7,945 km2.

Finally, the option for agriculture water reuse in the SPMR cannot be easily implemented, due to the fact that most of the treatment plants are located far from agricultural land. Even though demand is significant, the added costs are not attractive for rural producers and their consumers.

Responsible partner: University of Sao Paulo,USP

 

Study site 2

Chile Copiapó River Basin, Chile
The Copiapó River Basin, Chile

The Copiapó River Basin is located in the Atacama region of Chile, which is a semiarid region – with an average annual precipitation of 28 mm – and presents constantly growing water demands from many different users, adding increasing stress to the already scarce water resources.

The population of the Copiapó River Basin has increased exponentially during the last 40 years reaching almost 200,000 inhabitants in 2012. It is expected that it will face a rapid development in the next 20 years, driven mostly by the development of the mining industry.

Furthermore, a strong increase in its population is predicted, mainly in the city of Copiapó and its surroundings. Consequently, it could have a strong increase in the drinking water demand.

Mining, agriculture, residential areas and tourism are competing water uses.  Drinking water is becoming increasingly expensive and the water quality deteriorating. . Illegal water consumptions make the situation even more extreme. Finally there are several fragile ecosystems that are very sensitive to water scarcity.

Government agencies are trying to elaborate a series of tools that will register all the users and demands, and simultaneously manage the water resources in a sustainable manner.

Currently, the water demand is met using all surface water resources of the region (the entire Copiapó river flow is used for irrigation – 153 million m3) and groundwater resources. Unfortunately, the increase in demand has led to a situation where the intake from the aquifer is much greater than the recharge (6 L/s against 4 L/s) which results in a decrease of  volume stored in the aquifer and a situation of water scarcity.

Since 1988, studies have shown a net decrease of the volume stored in the aquifer, due to an overexploitation of the water resources.

The main water management issue in the region is that too many water rights have been granted during the last few decades, and not all of them have been registered with the water agency, leading to conflicts among the various users.

Despite the fact that the area already has some experience on water reuse applications, it is believed that the agricultural sector might present the greatest potential for larger scale applications.

Responsible partner: Universidad Católica de Chile, PUC

 

Study site 3

Mexico Lower Rio Bravo/Rio Grande basin, Mexico
The Lower Rio Bravo/Rio Grande, Mexico

This case study is focused on the Mexican municipalities of Reynosa, Río Bravo, Valle Hermoso and Matamoros, in the Mexican Tamaulipas State along the border with Texas, USA.

From Reynosa to the Gulf of Mexico, the watershed is facing a complex situation due to various water uses and demands. Irrigation, industrial and municipal demands are prevalent in this area. The tremendous water use in large cities and vast irrigated acreage along the river has taken a heavy toll on the river’s flow; less than one fifth of its historical discharge reaches the sea today.

The supply in the region depends heavily on superficial water. For centuries, the Rio Bravo has been the only dependable and secure source of fresh water. Groundwater is available, but its quality (high salt concentration) makes it useless for most of the demand. In some specific cases, however, it has been the only solution to water scarcity.

It is estimated that superficial water availability is about 1,360 hm3/year and groundwater availability is about 40 hm3/year, which translates into an availability of 1,094 m3/capita.

If the population reaches a 50% increase in the next 20 years (2030) as forecasted, the availability will drop to 730 m3/capita and will result in water scarcity conditions.

Water reuse and recycling in the area is almost inexistent. All the treated wastewater is discharged without any benefit to the agencies or society. This valuable source of water might provide the area with the means to better manage water scarcity now and in the future.

The main problem in implementing water reuse in the area economic: Large investments are required for the connection between wastewater treatment plants and future reclaimed water users. Financial aid and subsidies might be required for the solution of this challenge, as well as other pertinent issues.

Responsible partner: Tecnología de Calidad, TDC

 

Study site 4

Argentina Matanza-Riachuelo Basin, Argentina
The Suquia Basin, Argentina

The upper basin of Suquía River occupies a surface of 1750 km2, in a rectangular shape, with 70 km from North to South along the Punilla Valley, with an average width of 25 km. Human activities on its banks and surrounding areas are related primarily to tourism.

The Suquia Basin serves as the water source for the city of Cordoba. The metropolitan area of the City of Córdoba, with a population in 2010 of more than 1,400,000, is mainly supplied with water from the San Roque reservoir (Northern areas), and partially by Los Molinos-Córdoba channel, which delivers water to the South of the city. The basin’s water is also used for the irrigation of more than 2.000.000 ha, almost the 27% of the Country’s agricultural area.

During the last decades, long drought periods and floods have ocurred. These events, accompanied by land use changes, have worsen the current conditions and may affect the area’s development in the future.

Furthermore, progressive contamination in the contributing basin, and silting and eutrophication of the reservoirs generate situations where demand exceeds the system’s capacity. The deficits are exacerbated during dry years, increasing the degree of the system’s vulnerability.

In order to provide for the increasing demands and to decrease vulnerability, there is a need to augment the offer of drinking water in the city of Córdoba, ,which could only be accomplished  in detriment of some of the other uses in the system.

Water reuse could provide a viable solution for freshwater saving in the area. Yet, there are only a few, isolated, cases of water reuse in the area. The schemes were developed to serve irrigational purposes as a solution for the disposal of the treated water in sub-areas where no drainage system was available for that type of water.

Responsible partner: National University of Córdoba – UC

 
 

 

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