|IAEA Technical Co-operation - A Partner in Development|
Managing Water Resources
MANAGING WATER RESOURCESOver 70 percent of the Earth's surface is covered with water, but less than 3 percent of that is freshwater - most of it locked up in glaciers, ice caps, the atmosphere and deep groundwater reservoirs. Just 13 percent of the globe's total freshwater is readily available to meet human needs. In the meantime, worldwide demand for water is doubling every 21 years according to FAO. As industrial, agricultural and domestic pollution threatens finite supplies, water is becoming an increasingly precious resource that must be managed judiciously.
One growing emphasis in TC activities is helping countries and regions to investigate and manage water resources using isotope hydrology. Isotopes are extremely powerful tools for investigating many areas of natural science. Most elements are made up of different isotopes, which are nearly identical to one another chemically, but are of different atomic mass. The water molecule is made up mostly of two oxygen and hydrogen isotopes. But along with these are "rare" isotopes (H-2 and 0-18) occurring in relatively low and variable concentrations that permit a broad range of hydrological investigations.
Isotopic techniques provide an important analytical tool for managing water resources. The Agency has established a dedicated isotope hydrology laboratory in Vienna that supports national development activities. Typically, Agency assistance aims at developing experience and know-how through training, expert advice and the provision of equipment to improve local infrastructure and build capacity to study water resources using tracer isotopes.
Over the last decade, the IAEA has supported some 160 TC projects amounting to US $ 18.8 million to assist 63 countries in developing their capabilities in isotope hydrology applications. More than 550 students have been trained to apply isotopic investigations for natural resource management. TC projects are more and more designed to tackle practical problems in Member States. The following stories portray projects that are making substantial contributions to better water management and an improved quality of life for communities in water-short regions of the globe.
Moyale, near the Ethiopian-Kenyan border
The abundance of water in the highlands, however, contrasts sharply with the acute scarcity afflicting the vast low-lying region stretching south from the central Rift Valley to the border with Kenya. Here, the search for water is a constant element of survival for the semi-nomadic herders who populate the area, and waterborne diseases, like intestinal parasistes and hepatitis, are all too common. The few, small permanent settlements that dot the region must rely on seasonal runoff from two short rainy periods, a few perennia springs and extremely rare, deep water aquifers.
So when a local water expert gazes out across the semi-desert landscape of the Moyale region, he doesn't really see the cacti, the herds of camels or the giant anthills. Instead, he's identifying soil types, fissures and cracks in the rocks, and variations in the surface structures and vegetation that might provide him with even the smallest hint that water is hiding somewhere down below.
"Both the climate and the geology are working against a good water supply for the Moyale region," explains hydrogeolist Zenaw Tessema, who works with the Ethiopian Institute for Geological Surveys (EIGS), based in the capita, Addis Abada. "We're trying to make the best out of the worst kind of conditions."
The scarcity situation could not be more pronounced than in a small settlement called Melbena, where local herders from the Oromo ethnic group bring their cattle for watering in one of the traditional and awe-inspiring hand-dug wells known locally as "ellas." Waiting patiently for their turn under the blazing sun are scores of rugged herdsmen and hundreds of head of cattle.
"We know from isotopic analysis that the well water they are consuming today is nonrenewable," explains Johannes Belete, a second groundwater specialist from the EIGS. "This water has been stored in deposits for thousands of years and probably fell when there was an entirely different climate here. Unfortunately, this well could soon go dry."
With such threats looming, building a composite picture of the water supplies beneath the Moyale Region is a necessary - but not necessarily easy - task. The modeling requires a variety of analytical tools and lots of field data. Mr. Tessema and Mr. Belete have been combing this region methodically for the past two years taking water samples, studying aerial photographs and even mapping their own whereabouts with a digital tracking device linked to an earth-orbiting satellite. It's all part of an IAEA-supported regional Model Project that is helping four water-stressed African countries to manage their resources better.
One of the more advanced tools being made available to EIGS and other co-operating institutions by the IAEA is isotope hydrology, a relatively new science that uses both natural and man-made isotopes to identify the source and track the movement of water both on the surface and below the ground. In combination with conventional geochemical analysis, isotope hydrology is now helping Ethiopian authorities to scientifically "map" the underground reserves across this entire region.
"The specialized analytical equipment, computer software and training are helping us to apply isotopic methods for the first time," says Ketema Tadesse, General Manager of the EIGS. "IAEA has provided us with the basis for managing our water resources in a rational and comprehensive way."
In an arid region like this, identifying and exploiting water on a sustainable basis is both a science and an art. Specific trees and surface geological formations are the first indicators the hydrogeologist looks for. Surface faults, cracks and rifts reveal more about where water may be flowing. Geophysical investigation, followed by test drilling then confirms the availability and the volume of underground water deposits. Finally, isotopic analysis can help to reveal the flow, velocity, sources, recharge and even the "age" of groundwater. Any decision to try to exploit it depends on the extent to which it is likely to be replenished.
Glancing out across the bone-dry brush land as miniature dust storms swirl toward the horizon, the non-specialist observer might easily be fooled. Just at the point where it appears bleakest some 60 kilometres north of Moyale town, Mr. Tessema observes, "This is one of the locations with the greatest groundwater potential in the entire region. We know that the calcium carbonate surface covers a very thick layer of sand that can yield significant quantities of good, fresh water." That's very good news for women and young girls who have to trudge over many kilometres of desert each day just to draw water from a UNICEF-funded borehole and diesel-powered pump.
But sadly, wherever a basic life resource is so scarce, human conflict appears inevitable, and the Moyale region is no exception. In a part of the world where the contrast between urban and rural lifestyles couldn't be stronger, it's little wonder that nomads and town dwellers are engaged in a political struggle over water.
Near the site of one of the largest "ellas" some 70 kilometres away from Moyale town, a young herder boy complains, "Ever since the borehole was sunk we've had to excavate our own well deeper - and we're getting less than ever before. Fewer and fewer herders are able to use this source because the town is pumping so much water for its own use."
Concerned that some people may be denied the very water that he has helped to identify, Mr. Tessema observes, "The needs of surrounding communities should be given top priority when a new borehole like this one is installed. They must be thoroughly consulted and be part of the decisions affecting the development of local water resources and their utilization."
This is not a new problem for any arid country, nor is it a problem that can be solved by water specialists or other scientists alone. But it is all the more reason for assessing scientifically and planning adequately the sustainable exploitation of water in this remote region.
While the southern region of Ethiopia suffers from acute water scarcity, another area is threatened by overabundance. Lake Beseka, which lies about 200 kilometres east of Addis Ababa, has been expanding at an astounding rate: just three decades ago it covered a 2.5 square kilometre area; today it is roughly 15 times larger at over 35 square kilometres.
The situation wouldn't be so bad if the water were suitable for agriculture or human consumption. Unfortunately, the underground water flowing in is highly saline. Compounding the problem is the fact that the country's main road and rail transport lines to the nearest seaports in Djibouti run right alongside the current lake border. During the rainy season they are frequently flooded, causing traffic congestion and sometimes, total disruption of trade. Even more troublesome is that the expanding lake is now less than one kilometre from the Awash River, a source of fresh irrigation and drinking water for tens of thousands of Ethiopians.
"The ecological balance of the entire northeast region could be threatened seriously if the lake is allowed to overflow into the Awash," says hydrogeologist Tessema. "But before taking any remedial actions, we have to investigate the inflow of water from all different sources to gain a full understanding of the problem."
There are numerous theories among water specialists about why the lake is growing. Some say it may be caused by irrigation runoff. Others speculate that deep groundwater is flowing from beneath the Fantale Volcano, not far from the lake's shores.
"Thus far only limited chemical analysis has been performed to develop a model of the inflow and outflow of the lake," explains Mr. Tessema's colleague at EIGS, Johannes Belete. "Isotopic analysis of water samples from the local springs, the volcano and rainfall will help to build a comprehensive picture."
With the skills and tools developed through the regional Model Project, and the co-operation of experts at the University of Witwatersrand in South Africa, the EIGS team is making steady progress towards gaining that picture by applying isotopic methods.
"The lake water threatens the highway more each rainy season," says Mr. Tessema. "This is the very neck of the country - the jugular vein. We've got to identify the problem of why the lake is swelling and develop a solution very soon."
Qena, on the Upper Nile
"Ninety-six percent of the country is desert and only 4 percent habitable," explains Dr. Taher Hassan, head of desert studies at the Research Institute for Groundwater (RIGW), a government scientific body located on the outskirts of Cairo. "But 96 percent of the Egyptian people live on that tiny portion of habitable land within a kilometre or two of the river banks."
As Egypt's population and demands for food and water have been continually expanding, national authorities have sought means to reclaim desert lands for productive use. The main constraint to further large scale reclamation, however, is that the waters of the Nile, albeit bountiful, are reaching their capacity.
"There are many restrictions now imposed on how Nile water can be utilized in agriculture, and many of the shallow wells near the river are unsafe for drinking," explains Dr. Fatma Abdel Rahman Attia, the woman who directs the RIGW and a key advisor to the government on water policies. "Groundwater is finally being recognized as the critical factor in Egypt's water balance. Indeed, it's the primary issue."
Just how important a factor groundwater has become is brought home in Marajda village, about 3 kilometres away from the Nile, where 20 fedans (8 hectares) of reclaimed land are growing wheat, alfalfa, date palms, fruit trees and sugar cane. "Access to river water at Qena is strictly prohibited by the irrigation authorities," explains Mansour Shahein, a young farmer who helps cultivate this lush oasis with his family. "Our farm relies completely on water pumped from 70 metres below ground."
But just where does this groundwater come from? Is it seepage from the Nile, from a separate aquifer or from deposits in the rock below? And is it a renewable resource?
These are the kind of questions that Mohammed Flefil, an Eastern Desert specialist at RIGW, tries to answer with support from the IAEA's Isotope Hydrology Section and a TC Regional Model Project now active in Egypt, Morocco, Senegal and Ethiopia "Many wells servicing these reclaimed areas are recharged from the Nile, but farther away they come from other sources," Mr. Flefil explains. "Isotopic data are helping us to identify these deep groundwater sources and to manage them effectively."
Some 30 kilometres out into the desert east of Qena, the Nile River is long forgotten amidst a sea of sand. Yet Laquita village, a small farming settlement, was established shortly after a well was sunk more than 500 metres into a deep underground source.
"The main water bearing formation beneath Egypt's desert area is Nubian sandstone, and the Nubian aquifer may extend from as far away as Chad and Sudan," says Mustapha Ahmed Awad, of the Siting and Environmental Department of the Egyptian Atomic Energy Authority - IAEA's principal counterpart in the regional project. "Isotopic methods should help us resolve the questions of just where this water originates and how much there is to tap."
Less than one percent of the world's total useable fresh water is found in the Middle East and North Africa, according to the World Bank. And Egypt's renewable fresh water availability stands at only 1,000 cubic metres per person annually, compared with over 18,000 for North America and over 5,100 in Western Europe. Undoubtedly, Egypt needs to make careful use of whatever new water resources it can identify.
"Sometimes you can't get the answers you need through the classical chemical-based approach to water analysis," says Dr. Moktar Hamsa of the Atomic Energy Authority, who helped to pioneer the use of isotopic techniques in Egypt. "Now, through our collaboration with the IAEA regional project, more groundwater experts are gaining confidence in isotope hydrology and recognizing its unique advantages for better water management."
A TC Model Project is helping to characterize the "Valle de Caracas" aquifer, thus enabling Hidrocapital, the water authority, to assess the quantity and quality of groundwater available during dry spells and for limited local supplies.
The city relies almost exclusively on treated reservoir water delivered by several pipelines. But water rarely reaches the crowded shantytowns, which depend on supplies sold from tanker trucks. The supply deficit has worsened each dry season due to the adverse climatic conditions and the steady increase in the city's population, which now exceeds five million.
Ironically, there is massive leakage from the concrete pipes laid below ground to bring water from the reservoirs down to the city. Furthermore, the natural drainage of the groundwater was partially blocked when the nearby Guaire River was "canalized" some years ago. With nowhere to go but upward, the groundwater, swollen by the leakage, has now risen so close to the surface that city subway lines as well as the foundations of other buildings are threatened. In most cases, this water can no longer be used by the thirsty population because it is contaminated with sewage and other pollutants. So in many parts of the parched city the sound of pumps attests to the ceaseless extraction of this polluted groundwater, only to be discarded.
To reduce dependence on surface sources and a total daily water deficit of over 260 million litres, a proper management framework for exploitation of groundwater was needed. Since mid-1994, a TC Model Project has been providing new information that is critical in addressing this challenge. Geochemical techniques are being combined with analysis of environmental isotopes to reveal the origin and dynamics of groundwater with remarkable accuracy and speed.
This information is being used to define the first conceptual model for the underground aquifer system, to assess the potential for extraction and to assist decision makers in planning the exploitation of the "Valle de Caracas aquifer. Isotopic analyses of surface and groundwater have been carried out at IAEA's lab in Vienna, and the selection of further drilling sites is based on the interpretation of both field and laboratory results. The project is also transferring technology and know-how to Venezuelan staff to maintain constant quality control of extracted groundwater.
By the end of 1995, the water authority, Hidrocapital, had "mapped" the aquifer system and identified and characterised its sources of recharge. They have also determined that water from specific depths could substantially reduce the drinking water shortfall and that other areas of the aquifer could provide water for irrigation and industrial needs.
According to Mr. Luis Araguás, Technical Officer for the project, "Currently about a thousand litres of water per second are being pumped from 65 wells whose sites and designs are based on the project data. This covers about one third of the initial water deficit." Recently, additional work has been completed providing additional water from surface sources. However, adds Mr. Araguás, "The price of water from sources other than the "Valle de Caracas aquifer is higher because it would have to be pumped up to reach the city's elevation (950 metres)." While water leakage in the distribution network remains a big problem, a significant step has been taken towards improving the water security and welfare of the people of Caracas.
PARTNER IN DEVELOPMENTJANE GERARDO-ABAYA
Geothermal Expert, IAEA Headquarters
Isotope Hydrology Section Jane Gerardo-Abaya, a geologist educated at the University of the Philippines, has served on the staff of the Agency for the past three years, working principally on geothermal development. She was first introduced to nuclear techniques in hydrology 11 years ago when she learned to apply isotope methodologies as a TC counterpart in the Philippine government's national environmental agency. Her research then involved investigations on groundwater salinity in Metro Manila, through a project funded by the Asian Development Bank.
Continuous interaction with the Agency through TC projects and a fellowship deepened her experience on isotopes. She then moved to a geochemist position in the geothermal group of the Philippine National Oil Company-Energy Development Corporation. There, she was extensively involved in exploring potential areas for development and in investigating reservoirs for changes due to exploitation.
"In the Philippines, we employed both isotope and geochemical methodologies extensively the first time when the Agency assisted in a TC project. It helped to improve the interpretation of the complex hydrogeochemical processes during exploration and reservoir management," she says. "Integrating stable isotopes into the traditional methods gave us a much better understanding of the origin of different types of fluids, mixing of cold water, the flow of reinjected wastewater and other processes."
Now Jane is on the other side of the fence, working with the IAEA Member States as a Technical Officer for geothermal projects in Latin America, Asia and Africa. She has served as the Technical Officer for a Model Project in El Salvador, and another in Costa Rica.
"Having been a national counterpart, I understand the data, logistics and training needs, as well as the problems encountered in projects, and how these can be addressed," she explains. "Much can be accomplished with Agency assistance when there is a strong commitment by the counterparts to achieve results."
Jane's strong motivation is derived from the awareness that her work at the Agency is beneficial not only for the recipients of assistance but for proper management of the environment and natural resources.