The crossword solution for the term GRAND COULEE, E.G. is DAM, a three letter word. The Grand Coulee DAM is a large hydroelectric DAM located on the Columbia River in Washington State, USA. It was built between 1933 and 1942 and is the largest concrete structure in the United States. The DAM provides irrigation water for over 1 million acres of farmland and generates enough electricity to power over 3 million homes.