Urban Ecology and the Need to Balance the Value Scale of Water

The goal of urban ecology as a scientific study is to achieve balance between human culture and the natural environment. This balance, however, currently establishes values to our resources based on consumption, economic and social development. The equation assigns values of availability and extraction, established at the turn of the 20th century, at a time when natural resources and our Earth’s ability to absorb our impact were abundant. The 21st century, however, has brought to us the challenge of transforming the flawed equation of human development and nature based on the ecological life cycle of the availability of our resources and their consumption. As we move to a possible world where cities will have no water, the essential question becomes: How can we return what we utilise in a responsible manner?

Take the example of a ball point pen, valued at 10 cents. Our modern-day environmental value system of development focuses on the extraction of the resources and labour process (mechanised and/or cheap) required to produce the pen. But if we were to place ecological value to the pen based on life cycle, the pen, whose use is currently expected to be a few months and its impact as waste on the environment to be a few thousand years, then its value would be closer to a couple of thousand dollars, forcing us to produce the most everlasting pen that did not warrant another one in our lifetime.

In essence, the greatest ecological flaw we face in the 21st century is that all major social decisions have been based on the current value of extraction of resources and not on the impact of reestablishing ecological balance. And this erred value system is most prevalent in the management of water. For more than 10,000 years, fresh water was valued as a fundamental source of sustenance for a civilisation, to be used, treated and returned to the environment (i.e., water for drinking, agriculture and health). With the arrival of machines and the industrial revolution, most societies changed that value of fresh water and converted it into a unit of power and energy. The water wheel became a key component for one of the largest sources of power, an easy and efficient way of obtaining energy. Water became a measurable unit of utility, and therefore a resource that man could somehow guarantee for the evolution of any society via machination and invention. We transformed water from a resource to be extracted, used and returned in a balanced manner for sustenance, into a resource that must be transformed into something useful for society: energy.

The history of the Valley of Mexico illustrates our change in environmental value assigned to resources. In the 13th century, Mesoamerican agriculture developed the system of chinampas, a technique which relied on small, rectangular areas of fertile arable land to grow crops on the shallow lake beds. Built on wetlands of a lake or freshwater swamp for agricultural purposes, the chinampas ensured sustainable agricultural development for the Aztec Civilization.

A chinampa plot was constructed by staking out a rectangular enclosure, about 30 m in length and 2.5 m in width, into the marshy lakebed. The enclosure would then be fenced in by joining the stakes with wattle. After that, the fenced-in area would be filled with mud and decaying vegetation. To prevent the roots from becoming waterlogged, it was important that the fill brought the chinampa plot above the lake level. While constructing the next plot, which would be parallel to the first, a narrow canal for the passage of canoes would be made in between these two chinampa plots. To further stabilise these plots of land, willows were planted around the perimeter whose dense root system anchored the retaining walls of the structure and reduced the effects of erosion.
 

The goal of urban ecology as a scientific study is to achieve balance between human culture and the natural environment

To ensure that the chinampas produced good harvests throughout the year, it was vital that the supply of water was well managed. During the rainy season, flooding would have been controlled through a sophisticated drainage system, which included dams, sluice gates and canals. During the dry season, however, moisture had to be maintained, and this was done manually by carrying water in containers from the canals to the plants in the chinampa plots. As for fertilisers, the Aztecs used human excrement collected in canoes from the city of Tenochtitlan. By using human excrement to fertilise the crops, the Aztecs were also able to create a healthier living environment as the city’s wastewater would also have been treated.  The environmental cycle was highly valued in the Aztec society, and therefore the chinampa agricultural system helped support 5 to 6 million citizens at the height of the Aztec Empire.

Today, the Valley of Mexico and its lakes are overrun by the expansion of Mexico City metropolitan area with a population of 22 million people over a built-up area of over 8,800 km2, a rapid urban expansion typical of the urban centres in developing countries. Neglect in developing a balanced extraction of water, consumption and wastewater management, has seen the crisis of water aggravate in Mexico City where the idea of abundant water has all but been forgotten. The lakes were completely engulfed by urban development, which took for granted the valley’s fertile land and water. Today, the chinampa structure of plotting and agriculture still exists, mainly in the modern-day borough of Xochimilco, where Lake Xochimilco used to exist, located about 20 kms from the centre of Mexico City. It has become a tourist destination where weekend travel through the canals is viewed as a voyage through the nostalgia of the old Valley of Mexico. Sadly, a historically efficient system of water and agricultural management proven to sustain a large population was abandoned, forgotten and mainly viewed as a tourism novelty to reminisce about the past. The ecological value of water was lost and therefore the importance of maintaining a sustainable cycle of extraction, use and return.

In contrast, the construction of the Panama Canal, an 82-km stretch on the narrow, rugged tropical Isthmus of Panama, began in 1904, lasting 10 years. It became one of the great accomplishments by mankind at the height of the industrial revolution. Some 3.4 million cubic metres of concrete went into building the locks, and nearly 240 million cubic yards of rock and dirt were excavated during the construction phase to create an elevated navigable waterway made to shorten the shipping routes from the Pacific to the Atlantic Ocean by 3 months and 13,000 kms. At the time, it was the most expensive construction project in U.S. history, costlier than most of mankind’s wars. David McCullough famously wrote in his book The Path Between the Seas, “Strongly as the Panama Canal appeals to the imagination as the carrying out of an ideal, it is above all things a practical, mechanical and industrial achievement… The Canal set the standard and was the ‘world’s first’ of a great many things: the world’s largest dam, the world’s greatest man-made lake and the world’s highest locks.”

The ecological value of water was lost and therefore the importance of maintaining a sustainable cycle of extraction, use and return

Water, a key natural resource, was mechanised and made readily available in the interoceanic region, and became a given in Panamanian society without much concern for ecological balance in its expansive growth. This argument is true of Panama City’s potable water system. Early canal engineering projects provided the cities of Colon and Panama on either side of the Canal with reliable drinking water, seen as a key logistical strategy to ensure the successful construction and operation of the Canal. The Miraflores Water Filtration Plant (Pacific side) and Mount Hope Water Filtration Plant (Atlantic side) were built, which basically guaranteed fresh potable water to Panama City, Colon and the interoceanic region. At the time, having a water filtration plant was a rare privilege for early industrial area cities with marine facilities such as ports, navigation channels and marinas.

Since 1904, when the Canal was first started, the population of Panama City has gone from about 20,000 to 1.5 million in the metropolitan area, and physically expanded from about 20 km2 to over 2,500 km2 (metropolitan area). Known for abundance of water, the interoceanic region made shocking headlines when the Canal was forced to ration water to the city in 2019 as a measure to conserve water during a drought stemming from the El Niño climactic phenomenon. The rationing brought about the inconceivable notion that the city is water vulnerable despite being in one of the most water abundant regions of the world. A clear result in placing value on availability of water rather than ecological balance. The indiscriminate urban and sub-urban growth of the metropolitan area has impacted the interoceanic region’s microclimate in the way water is captured, used, returned and conserved.

Value to our natural resources must be assigned based on cycled ecological balance and therefore we must weigh the impact of how we develop our cities and built environment. Our reluctance to change to such a balanced perspective of man and nature, is based on our fear that we have surpassed the tipping point where our natural resources cannot provide and absorb man’s urban and sub-urban expansion. Instead, our society circumvents the problem by assigning new values of availability to resources and by finding new machinations to guarantee our resources. We keep asking the wrong question so we can get the answer that suits us (which is usually wrong). In the Valley of Mexico, the right question should involve preserving, replicating and expanding the system of chinampas to a scale that can sustain a large population and establish that as the tipping point of urban growth of the city. In the case of the interoceanic region, where water has always been perceived as guaranteed and abundant, the change starts with a cultural value assigned to water. In both cases, the greatest challenge is telling man what he cannot do based on changing values of resources that he always took for granted. The flawed equation that water will always be guaranteed somehow must be replaced by a question: How can we guarantee returning water back to the environment in a responsible manner?

All Photos: David Rodríguez