| dc.description.abstract | Groundwater is an important resource for drinking water, irrigated agriculture and industry. It also is a key factor in the preservation of ecologically relevant wetlands. Degradation of groundwater is a serious problem in natural resources management Groundwater is vulnerable because it can be depleted due to over-exploitation or to recharge reduction. It also can be polluted due to human activities. In (semi-)arid regions availability of water is (extremely) low, and the demand rises tremendously if the population increases. This easily can lead to an undesired situation. A rational use of land and water resources in these dry environments requires a systematic collection of ample hydrological data to set supra-national, national and regional water policies. Data gathering also is required to develop water resources plans, to design water resource systems, to operate the structures that make up these systems and to monitor if the predicted consequences of the implemented systems really occur. Despite the great need for hydrological network data in dry regions, the networks are best developed in the humid-temperate, mid-latitude, industrialized countries (Committee on Opportunities in the Hydrological Sciences et al., 1991). In many dry countries, data and knowledge of local hydrological cycles are woefully lacking
In the fourth phase of the International Hydrological Programme (IHP-IV), UNESCO decided to carry out a project on 'Preparation of guidance material on integration and co-ordination of soil-water monitoring systems to support groundwater resources assessments'. The objective is: to provide guidance material for setting up and maintaining efficient databases for groundwater related monitoring systems as a base for groundwater management' (Project M.1-1(b), UNESCO, 1990). Monitoring is defined as 'the continuous or frequent standardized measurement and observation of the environment (UNESCO, 1992). In 1991 at the International Association ofHydrogeologists (IAH) Congress in Tenerife and later at the UNESCO programme meeting in Paris in 1992, it was decided to limit the project geographically to the (semi-)arid regions, because of the urgent need to encourage groundwater monitoring there. Although somewhat vague, (semi-)arid regions are characterized by the smallness of precipitation (Lerner et al., 1990), on which all other environmental attributes depend (e.g. high radiation, low humidity, sporadic rainfall with a high spatial and temporal variability, short-duration runoff events, large groundwater storage changes. distinctive geomorphology: FAO, 1981). The outcome of the project is this technical document. In this document the term (semi-)arid includes both the so-called arid and semi-arid regions of the world. | en_US |
