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Energetic Evaluation of the Current Urban Watering System and Proposals for the Management of the Water Resources in Mexico City – Research Project for the Mario Molina Center www.centromariomolina.org

 
 

Introduction

The water resources have proven to be a decisive factor for the development of civilizations. Water, at some point synonym of abundance and provisioning, now refers to scarceness and risk. The uneven patterns of urbanization have transformed the hydrologic system. This has caused alterations in the quality, quantity and distribution of water; the careful management and remediation of these alterations depend on the environmental viability of the city.

In the Metropolitan Zone of the Valley of Mexico (MZVM), 97% of the population has access to drinking water and 98% counts with drainage services, which positions it above the medium percentage of the world’s population that counts with both these services (CONAGUA, 2012a). Nevertheless, there are deficiencies in their quality: their operation is very vulnerable to the variations of the rainfall, to the sinking of the city, to the overexploitation of the aquifers, to the high operating and maintenance costs, as well as the transferring of water from other basins which are becoming more and more distant. All this translates to a watering system that consumes elevated and increasingly high amounts of energy, which implies soaring costs for the public budget and a bigger environmental footprint, directly and indirectly.

Aware of this problematic, and congruent to their targets to transform Mexico City into a truly sustainable entity, the Government of the Distrito Federal (GDF), has showed interest in alternatives that set themselves apart from the conjunctural works with reduced strategic vision to favor models that are capable of offering informed, long term, and integral solutions.

In this context the present study has been elaborated, whose main objective constitutes in presenting a diagnosis of the energetic performance and the management of water in the Valley of Mexico. From this, a proposal can be made to reorient the infrastructure and management of this resource to a more sustainable hydric system. Below is an outline of the content of this proposal.

The first chapter makes a historical recount of the development of the different systems utilized to manage the shallow lakes’ water that harbored ancient Tenochtitlan. This revision emphasizes on the structural flaws that characterized the urbanization model that the city underwent during the Colonial Period. These imperfections have a direct impact on the deficiencies that illustrate the actual watering infrastructure. Also, the most important decisions to secure the supply, expulsion, and treatment of water are described. These decisions have been continuously nuanced by an institutional inertia that has confided little on alternate systems for the water management.

The chapter “Current Situation of the Urban Waters in the MZVM” describes the three systems that constitute the watering branching of the city: drinking water, rainwater, and residual water. The first is characterized by the continuous perforation of progressively deeper wells and the import of water from distant places. This has led to grave consequences on the soils, natural cycles and MZVM’s infrastructure. That’s why the report shows some of the risks of keeping the current patterns of the management of underground and shallow sources of drinking water. Meanwhile, the rainfall water system is proposed as a precinct traditionally framed in a context of floods and erosion, never considered as one of the most viable options for refilling the aquifers and a solution to the shortage of water in Mexico City. Finally, in what is referred as residual waters, there is a critical review of the combined system that is presently used. From this revision, the tendency to create grand infrastructure plans to expel the water is explained, never offering strategic solutions that allow the water to stay and be processed for its renewal.

The rethinking of the hydric strategy in the Mexico Valley demands knowledge about the efforts made by the CONAGUA and the GDF to try and fight the shortages and flooding problems that afflict the metropolitan zone. The fourth chapter describes, in general terms, the guidelines of public policy, programs and budgeted resources that jointly have constructed a program for the sustainable management of the water in the country’s capital.

The fifth chapter explains and develops a methodology for the estimation of the energetic rates with which the wells, sewage and treatment plants operate in the MZVM. From this, technical and strategic recommendations are emitted in order to reduce the energetic expenditure in the hydric systems. This analysis began from information provided by the Basin Waters of the Mexico Valley Organization (BWMVO), as well as a revision of the electrical billings from the Water Systems of Mexico City (WSMC) during the time frame of 2006-2009. The later were verified with direct measurements from 34 facilities through electrical wiring analyzers and flow meters. With the information provided by these tools, a diagnosis is presented. It talks about the energetic consumption and the costs of each stage in the management of the water resources in the MZVM. In addition, a landscape is drawn of the probable energetic consumption and financial burdens associated to the operation, of the year 2020.

The sixth chapter of the document deepens on the unavoidable future scenarios, consequence of water scarcity and the saturation of the sewage system. These two are, and will continue to be, product of the growing variation in the patterns of precipitation, the deterioration of infrastructure, and uncontrolled urban growth in the MZVM. The natural response in the face of this foreseeable future has been to look for new ways to broaden the capacity of exploiting residual waters alongside the expansive periphery of Mexico City. There is a detailed explanation of the Lerma-Cutzamala system, as well as alternatives that represent the Tecolutla and Amazcuac rivers. Also, the effects that these kinds of plans – some completed and some in progress – have on the ways of life of the population and the global sustainability of the basin are described.

It is imperative to note that other cities of the world have designed and implemented functioning systems to resolve water problematic similar to the current one in Mexico City. There is a selection of three case studies that have successfully created alternatives related to rainfall management techniques, residual waters, and the recovery of the urban ecosystem for the administration of water. These cases are: Venice, Porto Alegre and Orlando. They all promote the implementation of a sustainable hydraulic system.

The eighth chapter depicts the alternate hydric system projects that have had the most success in the MZVM. In the majority of the cases, there is a proposition to seize the rainfall as a strong alternate source for the supplying of drinking water. Besides, almost all projects reclaim the ex-lacustrine zones. Their main argument is that these bodies of water can serve as a buffer that controls the flow of water from precipitation and runoff. On the other hand, and serving as an interesting solution, the books Rethinking the Basin and Mexico, Future City talk about the recovery of the “chinampera” zone in Xochimilco and Chalco. All of these plans draw to similar conclusions, common vision needs to be generated and a separation from the prevailing hydric system in the MZVM is vital.

Parting from the presented projects and the government ideas, the last chapter has a vision for the Mexico’s Basin. It develops around two main premises: the creation of a Vegetation & Water Belt and a reduction in the expulsion of water from the Valley of Mexico. The Vegetation and Water Belt contains the expansion of the urban density and the promotion of the water cycles enclosed within the basin in a way that the extraction of water from the aquifers.

For the execution of these ideas, it is proposed to divide the basin into five subregions and eight elements through which the proposal can be taken into action. This way, a series of strategies are obtained that, with the help of the geographical situation, will assist each area to reconstruct their hydric system.

Finally, the legal and social actions that are necessary for the correct functioning of this alternate hydric system for Mexico’s Basin are presented. It is worth noticing the creation of a law for the treatment and management of the water within the Valley. Also, there is a development of various social programs that support the formation of a water-conscious culture. This way the efforts made to transform the water system of the MZVM into a more sustainable zone will seek the support of the society and the judicial system.
Map of Cortes, 1523.

Groundwork and Objectives 

The solution to the hydric problem in the Metropolitan Zone of the Valley of Mexico (MZVM) is a subject that has been repeatedly discussed for generations. This document dissects and diagnoses the current situation of the energetic consumption of the hydric cycle in Mexico City through the following tools: a) the analysis of a series of historical decisions that have lead to a situation of hydric stress and vulnerability to floods; b) the identification of policies, programs, and resources aimed to propitiate a sustainable management of water in the MZVM; c) an analysis of the energetic sustainability of the handling of water in this region (this is based from an evaluation concerning the distribution of water in accordance to its use, the management of residual waters and the expulsion of residual water and rainwater); d) a description of the future scenery in the case of continuing with the current trend of importing drinking water and exporting residual water; e) the revision of successful cases of water management around the world; f) a revision of the local projects, in order to give answers to the chronic scenery in the MZVM.

Parting from this series of elements, it will be possible to outline and sustain the urgency to establish a hydraulic system, alternative and sustainable, capable of dealing with the complexity presented by the functioning of the basin.

Main Objective

Presenting a diagnosis of the energetic and environmental performance of the water management system of the Valley of Mexico. The purpose of this is to generate a proposal that reorients the management of water towards a different and sustainable hydric system.
Vision of the basin.

  
Specific Objectives

The specific objectives are the following:
 
• Understand the origins of the current situation in the hydric system of the MZVM through the historical analysis of the development of hydraulic systems in Mexico City.

• Explain the operation of water management in the urban zones of the MZVM: drinking water, rainwater, and residual water; examining its current strengths and weaknesses.

• Define the current conditions (2011) of water consumption in Mexico City, identifying the challenges for the public administration. These are mainly the high supplying costs and the scarcity of the resource.

• Identifying the undertaken efforts by the CONAGUA and the GDF to elevate the sustainability of the management of water in the basin.

• Distinguish the public policies of water management in the MZVM according to the programs and budgets taken into action in 2009.

• Elaborate a database of the electric energy consumed for the process of extraction, expulsion, and treatment of water during the time frame of 2006-2009. Moreover, identify the sources of provision, levels of consumption, and estimation of the output for Mexico City.

• Develop a methodology for the estimation of energetic demand in the distribution system of water. The main three phases are extraction, recollection, and treatment.

• Quantify the consumption of electric energy and the flow of water through a sampling a number of wells and examining the treatment and expulsion of residual water plants. The Water System of Mexico City operates all the these procedures.

• Analyze the energetic consumption of the hydric cycle in the time frame of 2006-2009.

• Establishing the tendencies of the hydraulic situation of Mexico City for the year 2020. Considering the future demand and the expected costs of the supply, as well as its impact in the public finance.

• Define the energetic indexes in regards to water management and the consumption of electric energy.

• Identify the areas of opportunity for the saving of electric energy in the water sector, so that an outline with recommendations that propel the efficiency of energetic consumption can be created.

• Evaluate the repercussions of the current consumption and possible method to save of energy in Mexico City’s water cycle. This way it can be compared with the entire country’s energetic savings.

• Analyze three successful cases, of international character, in the sustainable management of drinking water, rainwater, and residual water. Then understand a way to apply them in the MZVM.

• Evaluate the strengths, weaknesses, and viability of the proposals that have been presented in a local manner with the objective of solving the hydric problem in the MZVM.

• Present a series of immediate actions to reduce the energetic consumption in Mexico City.
 
Propose a strategic planning project for the future creation of an alternate hydric system, one that is sustainable and has the tools to manage the water in the long term.

 

 
Strategic proposal for the basin.