Friday, November 23, 2007

Rainwater Management and Harvesting

With the increasing frequency and severity of droughts, compounded by growing population and urbanization, the issue of water management and rainwater harvesting are receiving more attention. Projections that two thirds of the world's population will be affected by water scarcity in coming decades make the issue particularly urgent.

A paper by the Stockholm International Water Institute divides water scarcity into three categories; demand driven (use to availability), population driven (water crowding), or temporary scarcity (drought).

Demand driven scarcity can be mitigated by reducing wasteful water useā€”cutting leaks in supply systems, losses in irrigation, reducing excessive household use, and cleaning up pollution.

Population driven scarcity requires reallocation, raw water transfers from other basins, water desalination, the use of groundwater through pipelines, and bulk water imports.

Temporary scarcity can be mitigated by water storage, resource allocation, rainwater harvesting, and the use of terracing in irrigated agriculture.

Water shortages around the world today tend to involve a combination of these factors as population increase, industrial development and climate change combine to stress existing water systems. Paved surface areas in growing urban areas increase the amount of water that flows directing into streams, reducing the amount refreshing aquifers. Demand increases while local supplies are stressed.

The situation in the U.S. Southeast and Southwest are slightly different. The Southeast, accustomed to plentiful rainwater, now finds itself in a record drought, having to cut back on traditionally higher levels of water usage. The Southwest, with fewer water resources, began with lower water usage per capita, but population growth and a stubborn drought, also finds its water resources strained. Urbanization aggravates the problem in both areas.

Urban runoff problems can be reduced through the use of raingardens and green roofs which reduce rainwater runoff by collecting and storing stormwater so that it can infiltrate the soil. These methods also reduce the amount of pollutants that are washed into rivers and lakes.

Rainwater harvesting collects rainwater in containers of various sizes, from rain barrels attached to gutter downspouts, to much larger containers geared toward supplying landscape irrigation needs.

In the southwest, rangelands of scrub brush, grasslands, marsh areas and deserts are common environments. Here, around forty percent of all rainwater evaporates directly back into the atmosphere, while only a little over one percent recharges aquifers. Proper management of the rangelands can have a major impact on the amount of water available for human use.

Worldwide, the International Council for Local Environmental Initiatives (ICLEI), best known for its programs to help cities reduce their global warming emissions, launched a water campaign in June, 2000, to work with local governments to reduce water consumption, pollution, and systems loss. The campaign has been particularly successful in Australia, in response to the record droughts of recent years. Some localities now have extensive rainwater harvesting programs, expanding the use of collected water to toilets and other uses.

More public education is needed as water stresses continue to grow in coming years.

Sunday, November 04, 2007

Resource exhaustion--the human price

Richard Heinberg's new book, Peak Everything, expands on the widely discussed possibility that we are reaching the world's peak potential for oil production, suggesting that other critical metals are approaching peak as well, including copper, platinum, silver, gold, and zinc. At the same time, the U.S. has become ever more dependent on mineral imports, with the value of mineral imports increasing from $4 billion in 1993 to $29 billion in 2000.

Constant exploitation has exhausted the richest ore deposits. Just as one example, U.S. copper mines in the 1920s worked with copper ores as rich as 20 to 30%. By 2000, copper ores of 0.3% to 1% were being mined.

The combination of increasing demand with declining yields has resulted in an ever growing pressure on developing countries to open up potential mining areas to access by western companies--many of which are located in indigenous or tribal areas. Anthropologist John Bodley, quoted in Resource Rebels, bluntly states that;
The disappearance of tribal cultures over much of the world in the past 150 years can be seen as the direct result of government policies designed to facilitate the exploitation of tribal resources for the health of industrial civilization.
Last week, I visited a gold mine site in Honduras that exemplifies many of the problems resulting from the pressures to produce more ore from poorer deposits. The San Martin Mine in the Siria Valley, operated by the Canadian company, Goldcorp, has been producing around one gram of gold ore per metric tonne of rock mined. Achieving this requires blasting half of a mountain into rubble, grinding the rock into finer pieces and then pouring a solution of water and cyanide over the resulting piles to leach the gold from the rock.

Cyanide leach mining has a history of disastrous accidents. A spill in Romania in 2000 resulted in dead rivers and polluted lands. In 1995, a tailings pond at the Omai mine in Guyana, gave way, spilling more than 800 million gallons of wastewater laced with cyanide and heavy metals into Guyana's biggest river, resulting in a major environmental disaster. Accidents such as these have lead the state of Montana to outlaw cyanide leach mining, with other state and national governments attempting to follow suit.

None of this has stopped mining companies from pursuing new ventures, such as the San Martin Mine mine. The mine began production in 2000. Indigenous villages in the area were moved to other land owned by the company and given fake land titles. Health problems soon appeared due to the blasting which spread dust contaminated with heavy metals into nearby villages. Over the years the mine has been in operation, nearby inhabitants have experienced a variety of skin and bronchial ailments. The incidence of miscarriage and birth defects has risen.

On top of medical problems, the mine's tremendous demand for water has dried up streams in the area, forcing the natives to rely on drilled wells, many of which have proven to be contaminated by heavy metal residues from the mine.

Honduran activists who have worked for mining reforms have had their lives threatened and their investigations blocked. In January 2005, the Honduran Office of the Special Prosecutor on the Environment called for a judicial investigation of the company for environmental crimes, forest crimes and water usurpation, but nothing has come of this.

The Honduran mine is scheduled to be closed in a few years, however Goldcorp has opened a new mine in Guatemala that is already showing some of the same problems experienced by the San Martin Mine.

I think it is important for people in developed countries to put a human face on the sacrifices made by indigenous peoples in the mad scramble to feed the ever growing appetite for raw materials. It presents yet another reason to work for a more sustainable, less wasteful economy.