For longer term stormwater management, a unit of this Ultra Passive Skimmer in every basin, vault, sump and holding tank will absolutely be most useful. With each skimmer being able to take 2 gallons of oil, you can simply leave it just like that to continuously catch and absorb oil as water passes it by.
The Ultra Passive Skimmer works passively as the only thing an operator can do is just to place it in a basin, sump, vault or holding tank and let it float there to absorb oil. There is a unique polymer absorbent that tie the caught oil to the polymer matrix, which therefore prevents leaching. Consequently it keeps your storm drain free from ponding or clog due to sediments brought by the water.