Browse Forums Building Standards; Getting It Right! 1 Apr 29, 2021 9:35 am I'm stuck in a difficult situation and hope I can get valuable advice from forum members here. As seen in the diagram below (sorry I don't know why it's rotated after uploading, you can "imagine" rotating it 90 degree counter clockwise), the storm water pit (900x900mm) is the lowest point in the land, and it's about 500-600mm below my backyard level, which can be a falling hazard (despite council insists it's not!!!). I wanna rise the pit so that it's level to the backyard but that's where the headache begins. I can think of 2 options for me, both with its own problem: Option 1: I can buy a precast concrete pit riser readily available from Everhard or Civilcast and put in on top of the current pit before backfilling to level it with the rest of the yard. There are 2 problems with this approach: a. Council argues that doing so will reduce the hydraulic flow from adjoining properties and if flood occurs in adjoining properties, I'll be responsible. It makes absolutely no sense to me. b. If I ignore council's comment and do it, I still face the issue of drainage for the yard. The water flow according to the original base ground level is sloping towards the pit and if the pit is risen, I need to find another way for the water to flow to the pit. I have a junction box near the house slab but it's on the high side and I don't know if it's possible to collect and direct the water there. Option 2: This is what I currently have (albeit temporary). I'm having a temp timber retaining wall around the pit. If I choose to go ahead with this approach, I might upgrade it to concrete sleepers instead of timbers. This approach will solve the issue of drainage as the agi pipe still can pour the water to the pit (which sits lower at the sleepers' bottom). But again there are issues with this approach: a. By right I cannot have retaining wall within 1m of the boundary. b. By right the retaining wall should not be across the storm water easement (which runs West to East to the pit) Is there any brilliant idea I can do to solve these issues? I'm in Sydney Southwest if that matters Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Re: Rising Storm Water Pit 2May 09, 2021 5:45 am If you built the house, do you have a drainage design? It could be that the pit was placed too low. Can you add some photos? It does sound like raising the pit is all that is required. But maybe you could just add a second lid up higher that allows water entry. https://*.com.au/article/who_is_r ... ter_drains Your neighbor is responsible for their own drainage. Re: Rising Storm Water Pit 3May 09, 2021 8:36 am "Your neighbor is responsible for their own drainage." that is not correct, neighbour is responsible for run off, not drains drain is part of easement and op's garden may not be the lowest on that section of pipe sounds like op's garden may have been raised, before or after construction Re: Rising Storm Water Pit 4May 11, 2021 11:36 pm Is the pit a surcharge pit? If there is a shared stormwater easement you need a surcharge pit to allow overflow overland in extreme rain events. These pits are normally above the surrounding ground level at the last point before leaving your site. You might be able to raise the pit if you install a new pit connected to it at a lower level to allow surcharge. If you raise it without a surcharge point your stormwater will flow upstream out of their surcharge pit flooding their property. best to listen to the council, or get a hydraulic engineer to help you or download AS3500 and read the section on stormwater drainage. Re: Rising Storm Water Pit 5May 13, 2021 1:10 pm "But maybe you could just add a second lid up higher that allows water entry" Yes I'm going to have a lid on top of the riser but I don't see it's possible for the flood water to rise that high "sounds like op's garden may have been raised, before or after construction" Yes. the garden has been raised so that it's level. Originally, it slopes from the slab to the pit (600mm for 4.5m) "Is the pit a surcharge pit?" It looks like a surcharge pit with a grate on top. "If you raise it without a surcharge point your stormwater will flow upstream out of their surcharge pit flooding their property." I don't understand this part. Can you elaborate? The whole street is pretty much has the same issue. Most of my neighbours choose option 2. To help you easily imagine, the ground level (which is also the pit level) of all slots in the street is sloping. Let say my ground level (and pit level) is x, then the whole street looks like this: [x+50] [x+40] [x+30] [x+20] [x+10] [x (mine)] [x-10] [x-20] [x-30] [x-40] [x-50] Re: Rising Storm Water Pit 7Mar 01, 2023 1:09 pm 4re5 Hi, sorry to resurrect this old pots, but how you solved this issue. I have the same situation with the exception that my pit doesn't have a grate but concrete lid cover. Regards, doesn't sound like its the same type of drain, so its not entirely the same issue. Given it has a concrete cover on it, Its unlikely to be for overflow. should be ok to put a riser on it. Check with council. Or if this is access to your sewer inspection, you can just extend it without contacting council. In my old place I put a marker next to it and cover d it in mulch lol. Re: Rising Storm Water Pit 8Mar 01, 2023 1:22 pm ponzutwo 4re5 Hi, sorry to resurrect this old pots, but how you solved this issue. I have the same situation with the exception that my pit doesn't have a grate but concrete lid cover. Regards, doesn't sound like its the same type of drain, so its not entirely the same issue. Given it has a concrete cover on it, Its unlikely to be for overflow. should be ok to put a riser on it. Check with council. Or if this is access to your sewer inspection, you can just extend it without contacting council. In my old place I put a marker next to it and cover d it in mulch lol. Hi, yes you are right. I checked and is not a overflow is just a inspection pit to where my neighbour has his LPD for the stormwater. Regards, Thanks for that, the PVC pipe is still about 40cm below ground level and it sticks out of the sand with no end cap or anything on it just open pipe, is this the finished… 2 10717 Hello I am developing 2 side by side units. Wish someone can help me on the following questions 1) Which stage should be the storm water pipe installed during the new… 0 7976 If you need to be able to access these then you may need to dig them out and cut them so you can add a socket and a riser to the required height. We normally add a… 1 6963 |