Optimum well sampling distance of groundwater levels in till and coversands.

Abstract

Spectral decomposition of groundwater-table profiles from the extremely wet year 1965 shows that the wavelength of 1710 m is the most significant for fluctuations in Pleistocene till and aeolian coversands in The Netherlands. Consequently, the optimum well sampling distance of groundwater levels in till and coversands is 855 m, whereas the average distance in the national groundwater network (12,000 wells) is 1600 m. The distance of 855 m corresponds to half the average distance between soil classes, mapped on the 1:25,000 soil maps. The design of an optimum groundwater well network will thus benefit from 1:25,000/1:50,000 soil maps and land use maps.