I have a 36 inch storm sewer that is flowing, but feeders to it are backing up, what can I do?
This storm sewer has a high volume of rain water going through it, however, there is a smaller feeder from a neighboring building toward the end of it that is backing up, because there isn’t room for it supposedly to drain into the main line. Now the 36″ main is slightly obstructed with hardened sediment over many years from my concrete plant, we’ve tried blasting it out with water jet/vacs to no avail, what can I do now? Someone suggested hiring little people with jack hammers? Or just do the most costly thing, by replacing the pipe. But if I do put in a new pipe, will it be big enough for the volume of water? Like I said, this pipe has been here for over 50 years, and the hill it has been draining water away from, has been developed over this time period. I have city/county storm water folks after me, but I guess I’ll need to hire and independent engineering firm to do a study, and to present it to the city/county folks, is this a wise course of action? How or can I get out of this with the least expense to my company?
I suggest you consult an engineering firm.
Should be easy to clear out a 900 mm diameter pipeline, send down some skinny labourers as long as it is well ventilated. To enhance the small feeder performance ensure the soffits of the pipes are matched and feed the smaller pipe in at an acute angle to create a venturi effect. This will dramatically increase performance. If the pipe is undersized from upper catchment development suggest upper catchment stormwater attenuation to your local council, the others problem not yours as they are creating the increase in flows from the reductions in upper catchment absorption and decreases in times of concentrations of the flows, hope this helps