Analytical studies on the impact of land reclamation on ground water flow

Land reclamation has been a common practice to produce valuable land in coa stal areas. The impact of land reclamation on coastal environment and marin e ecology is well recognized and widely studied. It has not been recognized yet that reclamation may change the regional ground water regime, which ma y in turn modify the coastal environment, flooding pattern, and stability o f slopes and foundations. This paper represents the first attempt to examin e quantitatively the effect of reclamation on ground water levels. Analytic al solutions are developed to study the ground water change in response to reclamation based on two hypothetical models. In the first model, the groun d water flow regime changes only in the hillside around the reclamation are as. In the second model, the ground water regime changes in the entire hill . Both models assume that the ground water flow is in a steady state and sa tisfies the Dupuit assumptions. Hypothetical examples are used to demonstra te how the ground water level, ground water divide and ground water submari ne discharge will change with the scale and hydraulic conductivity of the r eclamation materials. The results show that the change of ground water regi me depends mainly on the length of the reclaimed area and the values of hyd raulic conductivity of the reclaimed materials. It is also seen that the re clamation may impact not only the ground water regime near the coast areas around the reclamation site, but also that in the coast areas opposite the reclamation area. A reclamation site near Tseung Kwan O in the New Territor ies in Hong Kong, China, is used as a case study to discuss the possible mo dification of the ground water system caused by reclamation.