Of course, the main influence on streamflow is precipitation runoff in the watershed. Rainfall causes rivers to rise, and a river can even rise if it only rains very far up in the watershed-remember that water that falls in a watershed will eventually drain by the outflow point.
One US gallon of water weighs 133.526464 ounces. The calculations for that answer are below: 1 gallon = 8.345404 pounds 1 pound = 16 ounces 8.345404 X 16 = 133.526464.
Actually, a pint of water weighs 1.04375 pounds. So, although this phrase does not provide the EXACT weight of each liquid, it does provide a very simple rule for determining approximately how much liquids weigh. In the case of water, there are eight (8) pints of water in a gallon. Using this rule, a gallon (eight pints) would weigh approximately eight (8) pounds, which is very, very close to a gallon of water's exact weight of 8.35 pounds which is found in the more detailed and scientifically correct answers to this question.