The ecological challenge of hydrogeology

We must become better at finding, managing and conserving our groundwater resources, both locally and globally, say scientists at the University of Bergen’s Department of Geology

MORTEN STEFFENSEN

"The global environmental crisis means that we must always be on the lookout for new water resources. In Norway, we use surface water for the most part, but environmental problems mean that this is no longer good enough. We now need to prioritize a move to groundwater for both private and industrial use", say Professor Roy Gabrielsen and Associate Professor Noralf Rye of the Department of Geology.

Water research and the identification of groundwater souces are becoming priority areas in geology at the University of Bergen. Hydrogeology has already begun to leave its mark on the Department of Geology, which has already graduated one Ph.D. and nine M.Sc. students, most of whom have been studying groundwater in unconsolidated sediments. The next stage will be to explore for water in bedrock and draw it up and will involve the sort of expertise that dominates petroleum recovery research in the North Sea.

Sediments and bedrock

"Our research on petroleum reservoirs has given us knowhow that will be essential for research on water resources. Water has already become a scarce resource even in such a wet country as Norway, but in other parts of the world water shortages are already dramatic, and in a global context, we are now facing massive challenges. Per capita consumption is probably the most important single factor, particularly here in Norway. However, the enormous increase in world population during the past 30 years is also an important explanation, and climatic change may well be another" says Gabrielsen.

"In principle, groundwater resources in sediments and bedrock are one and the same thing, i.e. water held in pores below the groundwater surface, but since water in solid rock often accumulates in fractures, exploring for groundwater aquifers requires other methods than those needed to explore sediments.

"Solid rock types such as gneiss and granite usually lack the pores that we find in sedimentary rocks. However, as a result of stresses in the earth’s crust fracture systems are formed in such rocks. These fracture systems may serve as water conduits. The pressure caused by the weight of the rocks themselves may be enough to force the water to the surface when we puncture an aquifer by drilling a well, or there may be natural drainage routes to the surface that create upwellings. All this means that water is fairly evenly distributed throughout sedimentary rocks, while it only occurs in the fracture systems of solid rocks".

Poor water quality

"Conservation of the environment has long been a driving force in the development of hydrogeology at the University of Bergen. While this will still be important in the future, spreading the word on our research to the authorities and the general public must also be given priority", says Noralf Rye, who received the Nordiska Ekofonden’s Tellus Prize in Environmental Geology from the hands of King Carl Gustav of Sweden in 1995.

"A quarter of the population of Norway have to drink poor-quality water which is deficient in either colour, turbidity, odour or taste. The seriousness of the problem is shown by the number of water companies that recommend boiling water for drinking or cooking. The National Institute for Public Health estimates that as many as 250,000 days of illness a year are due to poor water quality, which shows how important it is to stress this topic", says Noralf Rye.

Some 14 - 15% of the population of this country get their water from groundwater sources; an interim goal should be to raise this figure to 30%. Groundwater has chemical and physical advantages that make it a particularly good source of high-quality water. Virtually all of our "problem" waterworks use surface water, often with a high content of humus and/or bacteria. Until recently, groundwater has not often been recommended as an alternative to expensive purification plants, even though such water undergoes a natural purification process as it seeps down into the aquifer.

"Even so, there are problems in more widespread use of groundwater", continues Rye. "Under the new Gardermoen Airport, for example, lies the biggest water reservoir ever found in Norway, in a gravel bed left behind by the last Ice Age. The reservoir has sufficient capacity to supply 100,000 people with water, but we will probably lose it as a resource because of the airport.

"As long as the consumption of groundwater is in equilibrium with inflow, levels will be stable, apart from normal seasonal variations. However, the great increase in water usage throughout much of the world has led to a dramatic drop in groundwater levels. As a result, the levels of rivers and lakes that normally communicate with the groundwater are also sinking. In the Middle East, for example, the level of the RIver Jordan has fallen dramatically and the Sea of Galilee and the Dead Sea have sunk by several metres in just a few years. Competition for water is likely to cause serious political conflicts in the future".

"Another problem is that groundwater reserves are being either exhausted or destroyed", says Rye. Consumption may exceed inflow, as is happening in Denmark, where coastal aquifers are filling with seawater, rendering them useless as sources of drinking water.

Political signals

The EEA agreement includes tough drinking water specifications and water-quality requirements for industry. "When water leaches from the surface to groundwater aquifers, it absorbs important minerals from the soil and rocks. This is the essential difference between mineral water and surface water. The EU has introduced requirements that ordinary Norwegian surface water does not satisfy. If we do not meet these specifications, which deal with chemical and physical composition, bacterial content and temperature, our aquaculture, food and tourist industries will be particularly hard hit".

The advantages of groundwater are not simply higher quality but also that it requires lower investment and operating costs, is well protected against contamination and entails relatively simple technical installations. One of the University’s most important partners in this field is the Geological Survey of Norway (NGU) which produces maps and databases of rock, sediment and groundwater resources. Among NGU’s current priorities is greater utilization of groundwater, as part of a major programme launched by the Government in order to improve water quality.

Hydrogeology: the science of water movement in soil and rock. [Back]

What is groundwater?

Water is found everywhere below the surface, in cracks in rocks and between soil particles. Below a certain level, the groundwater level, all crevices in rock or soil are full of water.

Around 68% of the world’s fresh water is groundwater, while snow and ice make up about 31% and water in rivers and lakes only 0.2%. [Back]