- Provide control rainfall in ponds Remote Impounding Basin, not to exceed two cubic meters or a height of water equal to 8 cm (so that the filling of Remote Impounding Basin) still has a volume of less than 46. API 2510 standard cubic meters as the volume of not less than 50 percent of large tanks) by installing a drain valve between rain. The patio area to the tank Remote Impounding Basin to control the flow of rainwater into the pit Remote Impounding Basin does not exceed the height limit.