Sentence Completion

Complete the sentence with ONE word from the passage for each blank.

The Dutch have reclaimed large areas of land from the sea using structures called polders. A polder is a low-lying tract enclosed by banks, from which water is continually pumped out. For centuries this pumping was powered by windmills, though electric stations later took over. Roughly a quarter of the Netherlands now lies below sea level, kept dry only by constant management of the water.

Land reclaimed from the sea in the Netherlands is enclosed to form a , and the pumping that keeps it dry was originally driven by .