Sustainability Policy Evaluation in Guanajuato, Mexico
Some fifty years ago, the State of Guanajuato in central Mexico was considered the country’s “bread basket” supplying most of its grain needs. Endowed with a valley that crosses the state from the east to the west, measuring almost 100 miles long and between 20 and 30 miles across, the “Bajio”, as this low valley is known had the ideal conditions for a diversified agricultural production.
The Bajio, crossed by the Lerma river, endowed with a benign climate and provided with large number of freshwater aquifers continues to be one of Mexico’s prime agricultural producing regions. So what has happened in the last 50 years? Why is it more necessary today than in the past to carefully watch the water resources of Guanajuato? There are three factors that, over time, have contributed to the current water resources problems:
- Population. Guanajuato’s population has been growing at a fairly high rate. This growth is affecting water resources since human settlements modify the natural paths of water. Also, the volumes of water withdrawn from rivers and aquifers and the returned wastewater have dramatically increased. Population is also the cause of soil cover modifications by deforestation and urbanization that have changed rain patterns.
- Accelerated Agricultural Production. Driven by the country’s population growth, the pressure to increase agricultural production in the state of Guanajuato has been mounting. Due to this pressure, Guanajuato’s agricultural producers have struggled to improve the yield of their land. Outdated technologies, limited amounts of surface water and a marked variability in the precipitation patterns have forced the producers to supplement the surface water which is used in irrigation with well water. This practice has resulted in over-pumping the state’s aquifers. The pernicious problem of aquifer over-pumping was identified more than 40 years ago when a drilling ban for new wells went into effect for the Bajio Valley and other regions of Guanajuato. Nevertheless, the illegal drilling of wells has continued relentlessly. The tangible effect of this practice has been a fast and worrisome decrease of the aquifers’ static levels.
- Surface Water Supply. The supply of surface water from the Lerma River to Guanajuato has also been decreasing over time. The reasons for this are varied. First, at the source of the river, water is being extracted and pumped over the mountains to supply drinking water to Mexico City. Second, population growth along the Lerma River basin is demanding more drinking water, and also, water for agricultural production and industry. Last, the Lake Chapala at the end of the Lerma River basin, has been gradually drying up for over two decades, requiring additional volumes that are taken away from the water that in the past was distributed among the states on the basin including Guanajuato.
It is evident that the Lerma River carries to Lake Chapala smaller volumes of water than in the past but a more obvious cause for the lake’s drying up is the near explosive growth of Guadalajara, the second largest city in Mexico. Guadalajara is geographically adjacent to Lake Chapala and draws its drinking and industrial waters from the lake. The national water authorities adamantly refuse to accept this fact as the main source of trouble for the lake. They believe that a reasonable level in the lake can be achieved by enforcing a 20 year old treaty that adjusts the distribution of the Lerma water’s among the states on its basin by using as the deciding criteria the following year’s long term precipitation forecast.
The Planning Process in Guanajuato in the Decade of the 1990s
At the beginning of the decade of the 1990s, the Government of the State of Guanajuato set as one of its highest priorities the need to change the direction of the state development. To do so, an effort to identify the strengths and weaknesses of the state -that also took into account the changes of Mexico and the World – was undertaken.
Between 1991 and 1994 the project Guanajuato XXI Century, was undertaken, having as its objective to “find a new mechanism to direct the state development”, and as one of its short term goals to “generate possible long-term futures that will indicate what actions to take in the present to reach the desirable future”. An integral part of this project, was the State Foresight Study, whose purpose was to “generate expected futures that can be used as guidelines for the state development”. To prepare the Study, a foresight dynamic simulation model that portrays the reality of the state of Guanajuato, ProEstado –Guanajuato was built.
Supported by Gaston Berger’s idea that the forces that shape the future can be found in today’s reality, ProEstado-Guanajuato was built to (a) identify the forces that are immerse in the State’s reality and (b) to make the reality and the forces interact to create the future change.
ProEstado-Guanajuato is a Systems and Control Engineering model, built as a set of linear differential equations, that are numerically solved over time by an algorithm that generates time dependent behaviors for the model’s variables.
Systems dynamics simulation models, like ProEstado, have the inherent property that the policies which control the behavior of the model (also known as policy variables) are separate from the mathematical structure of system that represents the phenomenon under analysis. This is very much like an automobile, where the driver applies his/her policies through control mechanisms (steering wheel, throttle, and brakes) so that the “transportation system” (the engine, the transmission, the brakes, the suspension) perform the way the driver wants it.
ProEstado-Guanajuato was originally built to examine the then governor Vicente Fox’s statewide policies, in search of sustainable ones, to be able to ensure that “present and future generations have the resources they need for their development”. This examination identified important weaknesses in several of Guanajuato’s sectors, one of them water resources.