Geography of the European Netherlands European part of the country can be split into two areas: the low and flat lands in the west and north, and the higher lands with minor hills in the east and south. The former, including the reclaimed polders and river deltas, make up about half of its surface area and are less than above sea level, much of it actually below sea level. An extensive range of seawalls and coastal dunes protect the Netherlands from the sea, and levees and dikes along the rivers protect against river flooding. The rest of the country is mostly flat; only in the
Delta Works by planted vegetation or revetments. Although the new plan brought along additional cost, it was received favourably. The re-considerations of the Delta Project indicated the growing importance of integrate environmental impact assessments in policy-making. The Delta Project of which the Delta Works are part of was originally designed in a period of time in what environmental awareness and ecological effects of engineering projects were barely taken into consideration. Although the level of awareness for the environment grew throughout the years, the Delta Project has caused numerous irreversible effects on the environment in the past. Blocking the estuary mouths did reduce