Reed, D.W. 1995a. Water Issues - a European perspective. Extended abstract "Norsk hydrologi – perspektiver etter 100 år", 6 October 1995, Oslo, 3 pp.
Water issues in Europe are many and complex, interacting with all aspects of life. Where once there was the simple ambition to survive, the industrial revolution brought an increased demand for water, greater co-operation, and an awareness of economics: the monetary costs of constructing water supply systems, and the social costs of water-home disease. Eventually, towards the end of the 20th century, a third fundamental factor fought its way onto the agenda. To resolve the key issues in water it is necessary to balance aspirations, costs and environmental concerns.
Nations aspire to develop, largely to improve standards of living. In many countries, there are strong demands for greater energy, self-sufficiency in agriculture, and more numerous manufactured products; increased water use is implicated in many of these activities. Unless carefully planned, each can lead to the degradation or over-exploitation of water resources.
Water-related aspirations persist in developed countries too. Some derive from increased leisure, such as sport, gardening, and tourism. Many individuals are keen to try technological developments that promise greater convenience, choice, style or speed, thus sustaining the demand for new products. However, industrial use of water is decreasing in some regions.
Whether it is strictly an aspiration, global population increase presents the greatest development pressure of all.
The direct costs of construction, operation and maintenance of water and wastewater systems are well understood. However, indirect costs can arise, for example when resource systems are damaged or destroyed through pollution or over-exploitation. Losses occurring as a result of environmental extremes (e.g. flooding and soil erosion) can be difficult to quantify. Some losses are intangible; for example, what price can be put on the loss of physical habitat or amenity if a wetland disappears through over-abstraction of groundwater?
There are many environmental concerns, including: the effects of urbanization; agricultural, industrial and wastewater discharges; acid rain; saline intrusion; waste disposal; and over-exploitation of resources. These can lead to a deterioration in the quality of surface waters and groundwater, and to a consequent reduction in aquatic and riparian habitats for flora and fauna. The over-exploitation of groundwater resources is of particular concern, in view of its inherent unsustainability, and because of the lack of widespread public awareness.
Important issues for the hydrologist include: excesses and deficits, surface water quality, groundwater quality, impacts of water/land use on physical habitats, climate change and variability, uncertainty in assessments, and (perhaps) establishing compliance. Tasks contributing to the resolution of these issues can be grouped in five broad activity areas: information gathering, appraisal, analysis, communication, and policy formulation.
Communication through publication, education and technology transfer is clearly important, but are hydrologists adequately equipped to intervene in political matters? Is it enough to be knowledgeable about specialized aspects of hydrology if the practical need is to promote and sustain a holistic view of water issues?
One philosophy is that, if you gather enough information, the answer to a given problem will become obvious. I do not believe this at all! The hydrologist has traditionally complained of having too few data. With so many types of spatial data becoming available in digital form, it is possible that a greater difficulty may be an excess of information, some of it of doubtful quality and questionable relevance to the study in hand.
I believe that it will be necessary to improve techniques for appraising - through experience, judgement, and effective graphical display - the information that is most relevant to the problem. Then, the analyst's talents can be dedicated to solving the particular problem appropriately and effectively. This is why I distinguish appraisal and analysis activities, and, of course, why statisticians increasingly separate exploratory data analysis from modelling and estimation.
If a feature of the early 21st century will be a surfeit of information, more traditional data shortages will undoubtedly continue to limit hydrological assessments. Future projections of water resource reliability or flood risk will still be limited by the relatively short periods of actual observations, and doubts about their "stationarity". Satellite data may summarize land use in the late 20th century brilliantly, but we do not have the corresponding historical information.
An extreme view is that improved mathematical modelling of systems is in part needed to compensate for the loss of local and historical perspectives formerly passed down from generation to generation. If climate or land/water use changes dramatically, the importance of a historical perspective may appear to be rather less. But does not the natural variability of climate inputs remain an important factor which can only be gauged by reference to long-term records?
Hydrological systems are exceedingly complex. Paradoxically, this may be something of a strength. The hydrologist's willingness to accept the limitations of a purely theoretical or experimental approach has led to important exploitation of statistical methods.
Though not without their critics, statistical hydrologists have contributed important advances in topics such as: the analysis of extreme values, regional frequency estimation, modelling stochastic processes, geostatistical mapping, and modelling inter-dependence (e.g. "joint probability" problems).
Other important challenges include: the detection of long-term trend, inferring small-scale variation ("disaggregation"), and the classification of regimes through various kinds of multivariate analysis.
Perhaps we will also see greater use of "resampling" methods to characterize uncertainty arising from the use of statistically small samples. With regard to short-term risk estimation, there would appear to be scope to make greater use of Bayesian methods to obtain conditional forecasts.
This personal perspective of key issues in hydrology should not be taken too seriously. The most important goal is to keep hydrology rooted as a useful science, providing assessments and estimates that support practical decisions, in addition to advancing understanding.
A particularly interesting mix of hydrological problems are relevant in Norway, not least those concerning acid deposition, hydropower and snowmelt. With an experienced and practically-minded community, I am sure that Norwegian hydrology will enjoy continued success, and contribute much to the understanding of European water issues in the next century.