Archive for September, 2010

Groundwater depletion rate accelerating worldwide

Friday, September 24th, 2010

Here is a connection that may not be so obvious – accelerating ground water depletion worldwide is adding to sea level rise. That is the finding of a forthcoming study – A Worldwide View of Groundwater Depletion by Dr. Marc Bierkens of Utrecht Universityslated for publication in Geophysical Research Letters, a journal of the American Geophysical Union.

How might that be possible? Well, the water has to go somewhere. Once its pumped out of the ground and used for its intended purpose, much of it ends up in the oceans, either through evaporation and precipitation or direct flow into the seas. Yes, some of it does infiltrate back into the soil and recharges underlying aquifers. Yet, according to the study, as much as 25% of annual sea level rise can be attributed to ground water withdrawn by human ingenuity.

Dr. Ramón Llamas, Emeritus Professor of Hydrogeology at the Complutense University of Madrid, Spain, has termed the growing global exploitation of ground water resources a silent revolution for its stealthy expansion and the lack of attention in both national and international water law and policy. It is high time that governments and policy-makers begin focusing on both domestic and transboundary aquifers and their sustainable management, not only to protect these dwindling and threatened sources of fresh water, but also to consider the global impact that their utilization is having on communities, dependent ecosystems, and now sea level.

You can read more about this forthcoming study in the press release AGU just issued. Here is an excerpt:

In recent decades, the rate at which humans worldwide are pumping dry the vast underground stores of water that billions depend on has more than doubled, say scientists who have conducted an unusual, global assessment of groundwater use.

These fast-shrinking subterranean reservoirs are essential to daily life and agriculture in many regions, while also sustaining streams, wetlands, and ecosystems and resisting land subsidence and salt water intrusion into fresh water supplies. Today, people are drawing so much water from below that they are adding enough of it to the oceans (mainly by evaporation, then precipitation) to account for about 25 percent of the annual sea level rise across the planet, the researchers find.


Applying these techniques worldwide to regions ranging from arid areas to those with the wetness of grasslands, the team finds that the rate at which global groundwater stocks are shrinking has more than doubled between 1960 and 2000, increasing the amount lost from 126 to 283 cubic kilometers (30 to 68 cubic miles) of water per year. Because the total amount of groundwater in the world is unknown, it’s hard to say how fast the global supply would vanish at this rate. But, if water was siphoned as rapidly from the Great Lakes, they would go bone-dry in around 80 years.


The new assessment shows the highest rates of depletion in some of the world’s major agricultural centers, including northwest India, northeastern China, northeast Pakistan, California’s central valley, and the midwestern United States.


Most water extracted from underground stocks ends up in the ocean, the researchers note. The team estimates the contribution of groundwater depletion to sea level rise to be 0.8 millimeters per year, which is about a quarter of the current total rate of sea level rise of 3.1 millimeters per year. That’s about as much sea-level rise as caused by the melting of glaciers and icecaps outside of Greenland and Antarctica, and it exceeds or falls into the high end of previous estimates of groundwater depletion’s contribution to sea level rise, the researchers add.

Dr. Salman on downstream riparians harming upstream riparians

Monday, September 13th, 2010

You may have heard the old adage that water will flow uphill toward money. It comes from the cynical political perspective that believes physics and gravity irrelevant in the management and allocation of fresh water resources. Putting that cynicism aside, water and all of its benefits and impacts have long been accepted to be at the total mercy of gravity and topography. In other words, absent artificial inducement, water will always descend to the lowest possible elevation. In an upstream-downstream relationship, this suggests that the upstream riparian always holds all of the cards and has effective control of the water. It also suggests that harm on the river could only be caused by an upstream riparian to a lower riparian. If it were only so clear-cut …

Dr. Salman M.A. Salman, formerly a legal advisor to The World Bank, just published a fascinating analysis on the harm that downstream riparians can inflict on their upstream neighbors through the concept of foreclosure of future uses. The article – Downstream riparians can also harm upstream riparians: the concept of foreclosure of future uses – appears in the latest issue of Water International, the official journal of the International Water Resources Association, and can be accessed free-of-charge here. In short, by claiming and enforcing water rights secured prior to those claimed by upper riparians, the downstream riparian can attempt to legally foreclose all possible future uses by its upstream neighbors. According to Dr. Salman, however, such foreclosure can constitute harm in violation of the “no significant harm” rule widely recognized as a cornerstone principle of international water law (and, more broadly, of international environmental law).

Dr. Salman article is likely to be highly controversial. Downstream riparians – such as Egypt, India, and Pakistan – have long championed the “no significant harm” rule and used it as their bulwark against claims by upstream neighbors aspiring to develop and exploit their riparian character. Now, such advocacy could become a two-edged sword. Nevertheless, Dr. Salman’s argument is straight-forward and erudite and is supported by pertinent case studies and scholarly pronouncements, including examples from the Nile and Ganges Rivers, the 1997 Gabčikovo–Nagymaros case (International Court of Justice), and the Baardhere Dam and Water Infrastructure Project on the Juba River in Somalia. Hence, there is no need to rehash his argument here. It merely suffices to say: downstream riparians, beware.

Disclosure: I am on the Executive Board of the International Water Resources Association.

The Greening of Water Law

Wednesday, September 8th, 2010

The United Nations Environmental Programme just launched a new publication The Greening of Water Law: Managing Freshwater Resources for People and the Environment at the Stockholm World Water Week. I served as lead author on the project while Stefano Burchi, Maaria Curlier, Richard Paisley, and Raya Stephan provided important contributions. UNEP has a news article on the release of the book here. And you can download the complete book here. The following excerpt provides a good overview of the content.

The principal challenge facing nations today is how to ensure that both people and the natural environment have adequate freshwater to sustain and nourish their existence. In many parts of the world, communities actually compete with nature for dwindling supplies, to the detriment of both. Most often, though, water for the environment is a secondary or even non-priority in water management practices, the result of which has gravely impacted the natural environment, especially the aquatic environment.

Water is an inseparable component of life, both human and environmental. It forms a relationship based on the intricacies of both the hydrologic cycle and the interdependencies of all life on Earth. When water resources are degraded, they can impact every form of life, including human life. The challenge, therefore, is to overcome the need for competition and to find ways to harmonize the water requirements of people with those of the natural environment.

Potentially, the most effective means for achieving such harmonization is to integrate environmental concerns into national and international water laws and policies. The goal of such integration is to ensure that the water needs of both people and the natural environment are considered collectively and balanced in a way that will further the sustainable use of freshwater resources while maintaining ecosystem integrity.

The greening of water law is both a theoretical and practical effort to implement that harmony through modification of the legal regime governing the management and allocation of freshwater resources. It is based on the recognition that the life and wellbeing of people and the natural environment are interrelated and even interdependent and that the coordination of the needs of these two water-dependent stakeholders will further the sustainable use of freshwater resources for both. It is also founded on the notion that by ensuring adequate supplies of clean freshwater for the environment, people, communities, and nations, the human condition can be enhanced through improved health and more sustainable resource exploitation and economic development.

Special thanks to Lara Ognibene, Arnold Kreilhuber, and Sarah Muchiri at UNEP for the wonderful opportunity to work on this project, and for their support throughout the process.