ENVIRONMENTAL-IMPACT ASSESSMENT ON LAND RECLAMATION PROJECTS IN THE NETHERLANDS - A CASE-HISTORY

Since the 12th century AD land reclamation is carried out in The Nethe rlands. Numerous shallow, salt or freshwater lakes were pumped dry, ch anging the lakes into polders. These persistent pumping activities hav e caused substantial land subsidence in the areas surrounding these po lders. In order to assess the impact of pumping water out of a planned new polder (Markerwaard) on the adjacent land areas, a large multidis ciplinary study has been performed. In this paper the geological, geot echnical, geohydrological, environmental and constructional aspects of this planned land reclamation project will be discussed. Furthermore, attention will be paid to potential measures for mitigating the harmf ul effects of land reclamation. It will be demonstrated that it was im possible to make reliable cost calculations of the potential damage to housing, infrastructure, crops and environment due to the constructio n of the polder, without proper knowledge of the geological conditions of the area and its wide surroundings.