I agree with Buzz on the ID, silver maple. They can also be red maple which grow on a wider variety of sites including bottom land. The leaves are quite distinct between the two and red maple can have a large heart. Bud of red maple are blunt and red, as are the most recent growth on the branch tips. Both flower early in spring with ripe seed by mid-june. Water maple may even refer to box elder (otherwise known as Manitoba maple, or ash-leaf maple, which has red heart and blunt buds and with current growth often purple). The more upland maples such as sugar maple and black maple have pointy brown buds and the seed is ripe in October.