Population growth and the price of water

There is a growing trend toward viewing water as a commodity, as exportable as lumber or oil and natural gas. So what are the factors influencing the marketability of water? The simple answer is population growth. World population is increasing by 50 million to 100 million people per year (US Bureau of Census, 1997).

The spiraling population growth is increasing the demand for and reducing the supply of clean freshwater resources. Demand is increasing for drinking water, residential uses (showers, watering lawns, etc.), and industrial processes, while the supply is decreasing due to point source and non-point source pollution. Pending demands for water export from the United States are further fueling interest in the value of water by legislators and the general public (Lethbridge Herald, 1997). Humans use 54% of freshwater runoff globally, which means that less than half of the freshwater runoff is available to maintain ecosystem functions that cleanse and purify water so that humans do not contract water-borne diseases (Stanford, 1997).

This heightened interest in water, due to its economic value and importance to societal health, is one of the driving forces behind non-point source pollution control. Yet, many people still question the need to control non-point source pollution since they do not view stormwater runoff as a valuable resource/commodity. People do not question the need for flood control (water quantity) measures since the damages due to flooding without the measures, and hence the economic benefits of flood controls, are readily quantified. The calculation of economic benefits related to stormwater quality measures are not as easily quantified, and are, therefore, much more contentious.

So what are the economic benefits of clean water? Recently an attempt was made (Costanza et al, 1997) to value the benefits provided by the environment to humankind. Direct (food, water supply, etc.) and indirect benefits (climate regulation, erosion control, etc.) were considered in the study. Most of the benefits were monetarily assessed based on a "willingness to pay" principle (for example, if an environmental benefit adds $50 to timber productivity as a result of increased forest growth, we should be willing to pay $50 for this benefit). The estimated average annual value of the benefits provided to humans by the environment was (US) $33 trillion (1994$).

This value is approximately 1.8 times the global gross national product (GNP) which is approximately (US) $18 trillion. This valuation is by no means exact and there are, no doubt, many people who would contest this figure. The simple fact that economists are trying to value the services/benefits provided by the environment, however, indicates that people are beginning to recognize the linkages between a healthy economy and a healthy ecology.

The valuation of water is readily demonstrated by the cost of properties near water. Within urban developments, homes and offices located in close proximity to clean water have been shown to have an increased value up to 30% (EPA, 1995). The strong affinity of people to water has enabled engineers to design stormwater quality/quantity wet ponds and wetlands within subdivisions which are not only functional but provide a sense of community and are economically justifiable in terms of the overall revenue generated by a development.

A growing concern with ponds that have a dual purpose (stormwater management and community amenity), is the potential for bio-accumulation (accumulation of pollutants in the tissue of animals), in wildfowl (Canadian Wildlife Service, 1996), that may use the pond, and aesthetic problems related to litter and oil or gasoline spills. These problems are prevalent where industrial or commercial areas drain into ponds and have prompted several municipalities to investigate a treatment train approach to stormwater management where upstream sediment and spill control devices, such as the Stormceptor®, are implemented for industrial and commercial sites prior to the municipal storm drain network, and hence the pond.

The value of water and the scarcity of clean water will only increase as the world population increases and the effects that humans have on its quality are better understood. This increased value can only strengthen legislative and voluntary efforts to ensure that the quality of freshwater resources is protected. Accordingly, requirements to enhance the quality of stormwater from urban developments will continue to be a prevalent issue, and the day is in sight where stormwater runoff will be viewed as the valuable resource nature intended it to be.