Lake Chapala: 2001 follow-up to saving Mexico's largest lake
This article is Part 3 of Tony Burton's series:
"Can Mexico's Largest Lake be Saved?" .
Part 1: May, 1997 - Can Mexico's Largest Lake be Saved?
Part 2: March, 2000 - The State of The Lake.
Part 4: May 2002 - Lake Chapala–Fish Farm, Farmland or Bungee Jump?
Part 5: April 2003 - A review of "The Lerma-Lake Chapala watershed: evaluation and management"
In recent months, an increasing number of postings (and replies) on Mexico Connect forums have focussed on the state of Lake Chapala.
The tremendous increase in interest in this very important topic is to be welcomed. The issues affecting Lake Chapala are tremendously complex ones. As a result, alternative viewpoints are inevitable. However, certain figures and ideas can now be considered "established" beyond reasonable doubt. This article will focus on putting some of these ideas in perspective and on suggesting a number of concrete proposals which may serve to open the debate about the most appropriate measures to take if we are serious about trying to resolve the lake's predicament.
None of the ideas in this article are new; most have been well documented in scientific papers for decades. This article is based on a paper about "rational water use" that I presented to an open Jalisco state forum on ecology in 1991. At that time, the paper was well received by the wide cross-section of people attending the event and was subsequently published in a Lakeside newspaper, in both English and Spanish.
Shortly afterwards, I was asked by one of the members of the State Ecology Committee if I might be interested in contributing to a State Ecology Plan. Despite accepting the invitation, I was never actually invited to any of their meetings. Later in 1991, I was able to formally present the ideas to the then municipal presidents of Jocotepec and Chapala, as well as to the soon-to- be-elected regional "delegado". Nothing tangible came out of these contacts, either.
Since then, numerous articles related to the water problems faced by Mexico, in general, and Lake Chapala, in particular, have been published in academic journals. This surge of interest and information now has to be channeled into constructive remedies. Offered in the hope that brighter minds than mine may succeed where I did not, what follows is an updated version of my original paper.
GLOBAL SCALE PROBLEMS
Around the globe, we face unprecedented ecological difficulties. On a daily basis, we are drastically changing the conditions of (and for) life on the earth by means of land clearance, unsustainable resource use, and pollution (air, water, noise, visual). The changes not only affect conditions for ourselves and for our descendants, but also for tens of thousands of plant and animal species which have no say (nor vote) in how environmental affairs are being managed.
WHAT SHOULD WE BE DOING?
There is an increasing consensus that in order to improve our future situation (as far as ecology is concerned), we need to keep four distinct aims in mind.
First, we should be striving to maintain the widest possible diversity of plant and animal species that we can since genetic diversity may prove essential for our continued successful stewardship of the earth. Unfortunately, at present, we are destroying species at a rate approximately one thousand times as fast as the average rate over the past 100 million years.
Secondly, we should be attempting to limit our pollution of air, water and land since many of the changes we cause not only affect our own quality of life adversely but may prove to be irreversible.
Thirdly, in the interests of our long-term future, we should be trying to reduce our current levels of use of many non-renewable resources. In modern parlance, this is the idea of "sustainability". Even allowing for the fact that we may be able to substitute renewable resources for non-renewable in some circumstances, many other resources have only a very limited life-span at current rates of use.
Fourthly, we should be trying to repair some of the damage that thousands of years of human occupation have caused, especially in sensitive areas.
WHAT IS NEEDED FOR SUCCESSFUL PROGRAMS?
It is also generally agreed that any successful ecological program will incorporate various components, including education, voluntary restraint and regulatory controls. Different social and political viewpoints will, of course, attach different weightings to each of these components.
In general terms, voluntary restraint depends on increasing the awareness of all of us, and is supported by programs of consciousness-raising which convince us of the real need for changes in how we use natural resources. Regulatory controls, which may precede or follow from this increase in public awareness, act as a protective umbrella for our limited natural resources and a further motivation for our active participation in conservation efforts. Educational programs serve to increase public awareness and to help develop thoughtful attitudes among those who will have to inherit the results of our present policies, mistakes and successes.
THE VITAL ROLE OF WATER AND LAKE CHAPALA
In many parts of the world, including the Lerma-Chapala area, the single most important constraint on further development is water. An adequate supply of water is essential for the maintenance or improvement of the quality of life of the inhabitants of the region as well as for improving occupational opportunities and for conserving the amenable climate of the area. This climate, of course, has been one of the major factors behind the large in-migration of North American retirees. If Lake Chapala were to disappear, the climate of the area would be affected. The climate would undoubtedly become one of "more extremes", with both higher and lower temperatures than previously. Indeed, many long-time residents of the Chapala area argue that this has already started to occur, in response to the lake diminishing in size.
But the future supply of water in the Lerma-Chapala basin does not only depend on rain. Future water supply also depends on the reserves of sub-surface "ground water". Indeed, in the long-term, these may well prove to be even more important than the river and lake water.
THE LAKE'S CURRENT (2000) SITUATION
The lake's surface level is measured with respect to a fixed height (arbitrarily fixed as level 100.0) on a bridge (now demolished). Measurements are in meters. Prior to 1991, the National Water Commission considered the lake to be "full" when its level reached 98.0. At that level, the volume of the lake is 8,125 million cubic meters. After 1991, the Commission changed its definition of "full" to level 94.8 (4,500 million cubic meters). At level 90.0 the lake would essentially disappear.
In early October, 2000, the lake level is at 92.2, a very critical stage, the lowest for this time of year (immediately after the rainy season) since 1954. The average depth of the lake is now about 2.5 meters. Excluding 1954, the lake is at its lowest October level for more than 100 years.
By way of comparison, it's worth examining the 1954 situation in more detail. Evaporation during the dry season (1954-55) reduced the lake by June 4, 1955 to its lowest level (90.8) ever recorded. However, abundant rains in 1955 and 1958 enabled the lake to recover to a level of 96.9 by December 1958 and it remained above 95.0 until 1982.
This year, the best estimates are that the lake may lose between 1.2 and 1.3 meters in level between now and the start of the rains next year. That is considerably less than the 1 cm/day rate mentioned in some Mexico Connect Forum postings but would still mean the lake might fall as low as 90.9 by next June. The bad news is that, this time around, the lake is not going to make such a spectacular recovery as it did in the 1950s, since water demands throughout the Lerma-Chapala basin are now much greater than they were then, and the ground-water reserves are far more depleted.
Going from early October's level of 92.2 to a level like 96.9 is impossible to imagine. For one thing, at that level, the lake would be 4.7 meters higher than it is right now and many buildings on the shore would be flooded. In fact, as noted earlier, this would exceed the National Water Commission's own definition of a "full" lake. In all likelihood, next June the lake will hold about 1,000 million cubic meters of water (level 90.9), far below the 3,100 million cubic meters (level 93.3) established by "El Grupo de Trabajo Tecnico para el Sanamiento y Ordenamiento de las Aguas de la Cuenca Lerma-Chapala" in 1991 as being critical. Below this level, severe water restrictions were to be enforced in various States.
THE PRIME CAUSE OF THE LAKE'S LOW LEVEL
Today's critical lake level is due to various factors. The most important is that the main river feeding the lake, the Lerma, brings a pitifully small quantity of water compared with a decade or two ago. Historically, the Lerma is responsible for about 50% of the water reaching the lake, with the remainder coming from rainfall. The upper reaches of the Lerma are used to supply domestic demand in Mexico City and Toluca, and other smaller cities, for irrigation of farmlands, and for industrial uses in some of the country's major industrial areas.
The unexpected benefit of the Lerma bringing only small volumes of water to the lake is that the contamination of the lake water from this source has virtually ended. One recent thread on a Mexico Connect Forum was based on a quote by Dr. Manuel Guzmán, Director of the University of Guadalajara's Limnology Institute, based in Chapala, to the effect that the low lake level made the lake water "fit to drink". Guzmán has been televised drinking a glass of lake water and has not suffered any ill effects. Lakes are efficient self-cleaners, provided they do not receive overly large quantities of contaminated inflow. At present, the most significant sources of contamination no longer reach the lake. Besides the case of the Lerma, Guzmán emphasizes that the outflow from the numerous water treatment plants around the lake no longer flows as far as the lake, but is seeping into the ground on the recently-exposed lakebed.
Taking this argument to its logical extreme, if or when Lake Chapala dries up completely, then all problems of water pollution disappear overnight. This should mean that our first priority should be to ensure that Lake Chapala receives water and our second priority should be to ensure that the water is clean water. Tackling these priorities in reverse order is a waste of time and effort.
CONTRIBUTORY CAUSES OF THE LAKE'S LOW LEVEL
Several other factors have contributed to the low lake level. First, rainfall has been variable and inconsistent in recent years. Secondly, temperatures have probably increased in recent years in the area, though this difference may be hard to prove given the paucity (and likely inaccuracy) of weather recordings in the lake basin. Any increase in temperature will have augmented the amount of evaporation from the lake.
Thirdly, a considerable quantity of lake water is piped to consumers in Guadalajara. The maximum amount is set at 7.5 cubic meters per second, or about 240 million cubic meters a year. The amount of water involved would not be a problem if the lake still received ample water from the River Lerma but, in the present situation, every drop of water counts and hence water piped off to Guadalajara has become a very contentious issue.
Fourthly, the bed of the lake is getting ever higher. This means that one hundred years ago, for example, any particular lake surface level represented a greater volume of water stored than it does now. This change of lakebed height is due primarily to ever increasing quantities of sediment being brought into the basin by "tributary" streams. The change of depth has further increased evaporation, since shallower lakes heat up more quickly than deeper lakes, and thus reach higher temperatures.
WHY HAS SEDIMENTATION INCREASED?
There are several reasons why streams flowing into the lake (even if they only flow once or twice a year) now bring more sediment into the lake. First, more and more of the surrounding slopes are being cleared of their original protective vegetation cover. Some clearance is effected by campesinos needing to clear land for planting. The slopes cleared are often far too steep for cultivation to be continued for more than a year or two. After that, the remaining soil is unable to support a cover of vegetation and is more liable to erosion by wind or water.
Secondly, clearance has been effected by land developers clearing hillsides for construction. This is very evident in the landscape today, and there are sound reasons for suggesting that this latter clearance is far more likely to cause extensive erosion than that caused by campesinos.
For instance, whilst the campesino clears his land with simple hand tools, and applies little compacting pressure to the soil, the real estate developer is much more likely to use heavy machinery, causing compaction of the surface to a degree where it is much more difficult for vegetation to regain a foothold, even if the area is subsequently abandoned.
The most visible areas of bare, eroded, land in the Chapala-Ajijic area have been caused by ecologically-unsound development. These are the areas which, following rainstorms, provide enormous quantities of sediment to local streams which then overflow their banks blocking the Lakeside highway, or damaging property. The volumes of sediment they transport are deposited in the lake.
WHAT ABOUT UNDERGROUND WATER?
The water level in wells in the Chapala area is dropping. While few if any studies have yet been made of this problem, it is, by common consent, a serious one. Up to now, well owners have relied on increasing the depth of their wells and/or on sinking new ones. Such a solution is obviously only temporary. As long as groundwater usage exceeds supply, the water levels will continue to drop. Water supply in this case is determined by the amount of rainfall, and the percentage of this rainfall which, by infiltration, enters the soil and eventually reaches the water table.
The velocities of water movement underground (again, not yet studied, to the best of my knowledge, in the Chapala area), are likely to be extremely slow, far slower than most people believe. For example, based on studies elsewhere, and with a water table gradient of about 1%, and a sandstone aquifer, water flows along the water table at a velocity of about 350 meters per year. For an equivalent situation in clay, the velocity can be as low as 40 centimeters per year! These velocities help determine the time it takes for the underlying aquifers to be replenished with water. They also determine the time it takes for groundwater reserves to help maintain the level of the lake. Some of the water reaching the lake today, from underground, originated as rainfall within the drainage basin hundreds or even thousands of years ago.
As a result, continued extraction of water from a well, lowering ground water levels on all sides, is something which should be carefully regulated if we want to have readily available water in the future. We are, quite literally, using water that is thousands of years old, and that will take thousands more years to be replenished.
Complicating the picture is the fact that it may not be as easy to replenish underground water storages as was previously thought. A recent paper by Christopher Scott and Carlos Restrepo (available at http://www.iica.org.uy/p2-13.htm) examines alternative scenarios for groundwater recharge in part of the Lerma basin and concludes that it is probably not feasible to restore groundwater to historical levels.
HOW FAST IS THE POPULATION GROWING?
The population residing in the Chapala region is growing. Ten municipalities - Jocotepec, Chapala (which includes Ajijic), Poncitlan, Ocotlan, Jamay, La Barca, Briseñas, Venustiano Carranza, Cojumatlan de Regules, Tizapán el Alto and Tuxcueca - border the lake. While a small number of the people living in these municipalities do not actually live in the lake basin, most depend for their water on either the lake or its surrounding water table. Hence, we can use the total population figures of these ten municipalities as a surrogate measure of population pressure on the lake. The preliminary results of the 2000 Census show that the combined population of the ten municipalities is 292,899, compared with an equivalent figure of 218,996 in 1980. These numbers mean that the population of the ten lake municipalities has grown by about 1.5% a year since 1980, slightly less rapidly than the 1.6% rate for 1970-80.
Water is also taken from Lake Chapala to Guadalajara, a city whose population is in excess of 3 millions. Its population, too, is growing very quickly.
IS WATER RATIONING THE ANSWER?
Current demands for water in Guadalajara exceed supply and rationing has been put into effect during the dry season for the past several years. No major engineering scheme to supply more water for Guadalajara is yet being built, though several have been proposed. It is therefore very unlikely that Guadalajara's demands for Lake Chapala water will diminish greatly in the immediate future.
Furthermore, short-term "band-aid" solutions to the "water problem" involving cutting off supplies totally for hours or days at a time, aside from being unpopular, have rarely been shown to work effectively. For one thing, residents stockpile water to ensure they have an adequate supply, during those hours when water is available. Much of this water is subsequently wasted, by evaporation, or by being replaced by newer, cleaner, water the next time their supply is reestablished. For another, people often leave hosepipes and taps open, so as not to miss the moment when the water supply resumes.
WHAT SPECIFIC OBJECTIVES SHOULD A WATER PROGRAM ENTAIL?
The major objectives of a comprehensive "water program" should be:
- To rationalize and limit water use, reducing waste to a minimum.
- To reduce total water usage to self-sustainable levels so that we live within our water-table means, spending the "interest", not the "capital" stored in lakes and ground water.
- To make people more conscious of the urgent need for careful water usage.
WHAT CAN WE DO, AS INDIVIDUALS?
The following list of ways in which we, as individuals, can contribute to a reduction in per capita water consumption is not meant to be exhaustive but merely an indication of some of the possibilities worth discussing. None of the suggestions implies any reduction in our quality of life.
HOW CAN WE SAVE WATER?
- Turning off tap when cleaning teeth, saving 3 liters a day
- Taking showers of shorter duration (saving 40 liters every minute), turning water off whilst "soaping up", or installing water-saving shower heads.
- Closing taps whilst washing dishes, saving up to 17 liters per meal-load,
- Cleaning streets and pavements by sweeping, not by washing them down - the washing down method contributes to the sedimentation in the lake, and wastes tremendous quantities of water in the process - most of this water does not end up in the lake.
- Using less water in washing cars - and cleaning them less often! Using a bucket rather than a hosepipe can save 390 liters.
- Flushing toilets less often, using a lower volume (by 5 liters) of water per flush.
- Using less water in watering gardens and lawns. Grass lawns, if kept green all year in a climate like Chapala's, are a particularly wasteful use of water - their "rough" surface, and huge surface area, considering every individual blade of grass, greatly augment evapo-transpiration (the combination of evaporation and transpiration from living plants) .
- Repairing any leaks in the domestic supply and distribution system.
In addition, avid gardeners and agricultural users might consider:
- Not irrigating crops at mid-day, but in the early morning or late evening when evaporation losses are lower.
- Not over-irrigating crops beyond the point where there is any corresponding increase in yields.
- Selecting appropriate plants to reduce water requirements. This includes "dry gardening" or xeriscaping.
CAN WE ALSO RECYCLE WATER?
Besides using less, we can, of course, achieve the same result, by reusing water:
- Collecting water running while we wait for warm water, whether in the sink or in the shower, and using it to water plants, or to flush toilet.
- Collecting dirty shower water for flushing toilet.
- Using dish-water for flushing toilet.
WHAT CAN COMMUNITY GROUPS, INCLUDING REAL ESTATE PROFESSIONALS, DO?
Community groups, real estate professionals and municipalities, can also promote savings in water usage by:
- Promoting reforestation projects (and by restricting the use of grass lawns!)
- Constructing "infiltration soaks" to increase the percentage of rainwater and runoff which can soak quickly into the ground after a storm. This reduces evaporation and sediment transport to the lake, and helps recharge groundwater.
- Metering and Monitoring water usage
- Reviewing the state of tubing and connections to ensure that water is not needlessly lost through faulty installations.
WHAT ROLE SHOULD THE MUNICIPALITY PLAY?
The local municipality should take various steps:
- Set up, and supervise, an educational subcommittee of the Municipal Ecology Advisory Board, with the specific task of implementing programs and activities which will achieve desirable educational objectives.
- Consider the construction of a series of "infiltration soaks", to be located at strategic points throughout the urban (and hence most impermeable) areas of its territory.
- Maintain all parts of the public water distribution system in good condition, avoiding the unnecessary loss of water through leaks or evaporation.
- Formulate, enact, and supervise, a set of environmentally sound controls on water usage. These controls might cover, among other things, the use of hosepipes, the use of water in washing streets, the washing of cars, water recycling by businesses, the installation of water metering systems and the covering of open "pilas" used for water storage.
- The installation of water meters would enable municipalities to charge a water rate more appropriate to its value or, at least, its real cost. At present, in the Chapala area, a flat rate is levied for water. This rate for a single family dwelling is about 28 dollars a year. Assuming a household usage of 292 cubic meters a year (a daily rate of 200 liters x 365 days x 4 people), each cubic meter of water costs 9.5 cents. Not surprisingly, therefore, "proposals to charge rates which vary from 5.5 cents to 70 cents per cubic meter, depending on municipality" (Lloyd Mexican Economic Report, April 1998) have provoked bitter opposition. Comparable rates (in U.S. dollars) for a cubic meter of water for domestic use include 22 to 46 cents in Southern California, 32 cents in Ottawa, and 1 dollar in Israel.
NEEDED - A PIONEER MUNICIPALITY
Someone has to make a start. Someone has to pioneer a rational water program and its implementation, and act as a catalyst for other areas. If we all sit back and say, "well, we'll do something when others do...", adopting what might be termed the NIMBY (Not In My Back yard) approach, then the situation will never improve.
The municipality that first adopts a rational water program can reasonably expect nationwide coverage for its plans as well as nationwide scrutiny. If successful, it can expect nationwide acclaim for its innovation. Such acclaim will inevitably result in political, and probably, economic opportunities as well as kudos.
A municipal approach does not mean that we shouldn't support wholeheartedly the efforts of higher authorities (at regional, state or federal level) to help solve the "problems" of Lake Chapala. We should continue to support them in any way we can but we must also be prepared to play our part in the process, as individuals and through municipalities.
At a municipal level, our involvement and commitment will imply an expenditure of time, planning and organization, but does not necessarily require any great financial expense.
Implementing a municipal water plan requires a combination of education, public awareness programs, and carefully considered municipal regulations and sanctions.
NEEDED - A PIONEER REAL ESTATE COMPANY
And why shouldn't a real estate company, or grouping of companies such as the Multiple Listing Service, take the initiative and initiate water-saving measures? Surely it would be in their own best interests to be seen to be doing everything possible to help the lake and, not coincidentally, maintaining the area's real estate prices?
Why couldn't real estate companies, for example, insist that all new developments:
- Xeriscape the exterior grounds.
- Install water meters
- Install devices like special shower-heads. These have been around a long time and can save significant quantities of water. If hotels in Patzcuaro can use them successfully, why can't homes in the Lake Chapala area?
For existing properties, how about an agreed-upon policy of only accepting homes for resale that have water meters and water- saving devices installed? How much could these modifications possibly add to the cost of a home? Or don't we value our future water supplies that much?
The first company that insisted on standards like these would be able to designate its properties as "green homes". This could easily be the start of a whole new niche market for the future!
HOW MUCH WATER COULD BE SAVED?
The amount of water that could be saved is considerable. Taking the population of the lake basin as 300,000, and assuming that about 1 million people (one in every three) in Guadalajara depend on Lake Chapala for their water, and assuming that every man, woman and child were to save only 20 liters of their domestic use per day, then the annual savings would be 9.49 million cubic meters. Taking possible agricultural and industrial savings into account, the quantity saved could be multiplied many times over.
Current domestic water usage in the Guadalajara-Chapala region averages about 270 liters per person per day, down from 290 liters five years ago. Comparative figures are 200 in Sweden, 150 liters in France and 135 liters in Israel. Many researchers have suggested that the Guadalajara-Chapala figure could easily be reduced by as much as 100 liters a day. This would imply potential savings of up to 47.45 million cubic meters a year. Over a five year period, this would increase the present volume of the lake by more than 11%.
WHY IS EDUCATION ABOUT WATER IMPORTANT?
Education plays a key role in water programs since people will not change their habits unless convinced of the need to do so, or of the benefits which may result.
We need to recognize the enormous pressure that water supplies are under, and that likely future increases in demand will exacerbate this pressure. We need to realize that our water supplies are part of a global ecological system, in which an action in one place may have a consequence elsewhere. At the same time, we must admit that we have imperfect scientific knowledge of the full workings of many parts of local ecosystems and of the risks inherent if we change any of their components. We also need to accept the fact that the components and relationships in any ecosystem are dynamic, not static, and that many of these changes (eg variations in rainfall) are likely to remain beyond our capacity to control.
We should also remember that great lengths of time may be involved in the processes, both natural and human-caused, operating within any ecosystem. In general, we can adversely affect ecosystems much more quickly than we can restore them.
SPIN-OFF TO OTHER ENVIRONMENTAL CONCERNS
This article has focussed on water usage because I believe it to be the most fundamental, and the most urgent, environmental concern facing the area. However, environmental awareness in other areas (eg garbage disposal and water contamination) will almost certainly be awakened by a successful water-usage program. This should make future environmentally-based programs that much easier to implement.
It may appear that the changes outlined here are insufficient to have any real effect on the future of local watertables and on the level of Lake Chapala. However, someone, somewhere, has to make a start on what must be seen at the outset as a long overdue and probably lengthy campaign to restrict and conserve local water supplies. We must act NOW, confident that, in the future, others will join our campaign, recognizing that their interests and needs are common to ours. Once rational water-use systems are in place, other regions, including Guadalajara, will be much less able to ignore the part that they too must play to ensure the long term sustainability of the region's water resources.