Last time I checked, rivers don't usually run uphill.

Underground and above ground storage tanks are commonly used to store petroleum products andother chemical substances. For example, many homes have underground heating oil tanks. Manybusinesses and municipal highway departments also store gasoline, diesel fuel, fuel oil, or chemicalsin on-site tanks. Industries use storage tanks to hold chemicals used in industrial processes or to store hazardous wastes for pickup by a licensed hauler. Approximately 4 million underground storage tanks exist in the United States and, over the years, the contents of many of these tanks have leaked and spilled into the environment.