Wetrix

The player receives a flat square of land and has the goal of gaining as many points as possible through managing a landscape of lakes and the water therein. This is accomplished by maneuvering pieces that fall onto the playing area, one at a time in a similar manner to Tetris, to sculpt walls, dams, and the perimeters of lakes. Water bubbles will begin to fall; these burst upon impact and flow realistically like a fluid across its surface. (Wikipedia)