SPATIOTEMPORAL ANALYSIS OF SPRING WATER ION PROCESSES DERIVED FROM MEASUREMENTS AT THE DYLE BASIN IN BELGIUM

This paper deals with the study of natural variations and mapping of s patiotemporal spring water ion processes by means of stochastic analys is. Natural variations in space/time are the result of the combined ef fects of the physical, chemical, and topographical laws as well as the uncertainties and heterogeneities underlying the phenomenon under con sideration, Maps of the space/time distribution of natural processes c onstitute a fundamental element of physical explanation and prediction , and are extremely valuable tools for numerous applications in enviro nmental sciences including, e.g., water quality management, solute tra nsport characterization, and human exposure to pollutants and hazardou s substances. The spatiotemporal random field theory is applied to spr ing water solute contents (calcium, nitrate, and chloride ions) which are irregularly distributed in space/time over the Dyle river catchmen t area in Belgium. The integration of the spatial and temporal compone nts in a space/time continuum has considerable advantages as regards t he analytical investigation of solute content processes. It provides a rigorous characterization of the ion concentration data set, which ex hibits a spatially nonhomogeneous and temporally nonstationary variabi lity, in general. The physics of the situation can be expressed in ter ms of differential equations that emphasize the importance of space/ti me continuity. The characterization of the latter involves certain ran dom field parameters. A rich class of covariance models is determined from the properties of these parameters that includes, as special case s, separable generalized covariance models. In practice, the results o f the space/time analysis may depend on the scale under consideration and, thus, a scale level must be specified that reveals important feat ures of the spatiotemporal solute content variability. The analysis le ads to maps of continuity orders and covariance coefficients that prov ide information about space/time solute content correlations and trend s. Solute content estimations and the associated estimation errors are calculated at unmeasured locations/instants over the Dyle region usin g a space/time estimation algorithm. The analysis is general and can b e applied to various data sets from environmental, hydrogeologic, atmo spheric, and meteorologic sciences.