D. Armstrong – författare

Analytical methods of assessing the response of groundwater levels to a range of factors, including elastic (barometric and tidal) influences in confined aquifers and recharge to unconfined aquifers due to infiltration of rain and other surface water, are presented. Responses in a confined aquifer to distant recharge events and the associated time lag is discussed. Also covered are responses to changes in storage volume resulting from direct recharge at the outcrop of an unconfined aquifer system both seasonally and on a single recharge event basis. Worked examples and case histories are used to illustrate methods of estimating the amount of recharge at different sites within a catchment. The application of vertical cross-sectional flow nets to the estimation of recharge is presented in the context of recharge/discharge profiles.

This booklet outlines the properties of geological materials which enable them to accept, store and transmit groundwater, together with a description of the principal types of aquifer which are commonly found to occur in the field. Sources of groundwater are described in order to provide an understanding of the hydrogeological modelling exercise. The governing equations for steady state and non-steady state (transient) groundwater flow, are presented together with a brief overview of a range of modelling techniques, including both analytical and numerical models, the use of diffuse recharge as a model calibration tool and recent developments in the field of inverse modelling are also discussed.