Browse Forums General Discussion 1 Jan 12, 2009 9:59 am Is anyone else subject to this Melbourne Water flood special building overlay?
Melbourne water have requested we comply with 6 conditions in our design. The problem is that 2 of the conditions clash. If we comply with condition 3, which is the height of the garage floor above flood level, we then can't comply with condition 5, which relates to the velocity and depth of water. If anyone else has been through this process and can offer any advice it would be much appreciated. Thanks JB Re: Melbourne Water 1-in-100 year flood Special Building Overlay 2Jan 12, 2009 11:46 am Yep, we had to deal with this. Our floor levels have to be 100cm above the ground level, implying that the 100yr flood level is 70cm above the ground. This is patently absurd, and results from using computer modelling rather than any actual historical data.
In the end, we decided not to have a garage, as it would have been 70cm above the ground, with a massive amount of concrete in the front yard. When we asked why the garage had to be so high, we got reasons like: "So that the car doesn't float way. So that chemicals stored in the garage are not subject to flooding and entering hte waterway. In case anyone was to sleep in the garage." Instead, we have no garage, meaning a car is more likely to float away. Any paint/chemicals we have will now be stored under the house, making it much more likely that they'll end up in floodwater. Crazy stuff, driven by bureaucratic need to minimise risk exposure by Melbourne Water, who have chosen to transfer the cost of upgrading the waste water system onto householders, who have to add costs onto their building instead. Good luck with your negotiations - we managed to get some concession on the height of our garage floor, but it was still to high for us to bother with. I've heard stories where people were made to build a metre off the ground like us, but then were forbidden from bringing imported fill onto the site to make this possible, as it would change the runoff velocity - Catch 22! I guess God didn't use subbies... Re: Melbourne Water 1-in-100 year flood Special Building Overlay 3Jan 13, 2009 7:37 am Thanks mate, we have gone back to them with a civil engineers computations and explained the predicament so we'll see what they come back with.
JB Re: 4Apr 06, 2009 1:02 pm MrT Yep, we had to deal with this. Our floor levels have to be 100cm above the ground level, implying that the 100yr flood level is 70cm above the ground. This is patently absurd, and results from using computer modelling rather than any actual historical data. Mate, I have a question. How did your concreters know where to set the finished floor levels? We have a "TBM nail in bitumen" in other words a nail in the street which is at 5.26m above AHD, but the concreters doing the strip footings and garage slab have asked that to be translated into 6.05m on the fenceline. Also I have to make sure I get the FFL at 6.3m - what's the best way for me to make sure these levels are accurate? How did you do it? Thanks JB Re: Re: 5Apr 06, 2009 4:45 pm James Bond MrT Yep, we had to deal with this. Our floor levels have to be 100cm above the ground level, implying that the 100yr flood level is 70cm above the ground. This is patently absurd, and results from using computer modelling rather than any actual historical data. Mate, I have a question. How did your concreters know where to set the finished floor levels? We have a "TBM nail in bitumen" in other words a nail in the street which is at 5.26m above AHD, but the concreters doing the strip footings and garage slab have asked that to be translated into 6.05m on the fenceline. Also I have to make sure I get the FFL at 6.3m - what's the best way for me to make sure these levels are accurate? How did you do it? Thanks JB We didn't have this issue, as our house was built on strip footings and screw piles. Never thought about how they got the right level, assume the surveyors set some reference point, and then they made sure that the brick piers around the outside and the screw piles were set to the right height. All I did was get the FFL levels from Melbourne Water, and let the builders do whatever they had to do to make it right... Good luck! I guess God didn't use subbies... Re: Melbourne Water 1-in-100 year flood Special Building Overlay 6Apr 06, 2009 8:23 pm James Bond Is anyone else subject to this Melbourne Water flood special building overlay? I looked at a property a while ago that already had plans and permits to build a couple units but upon further investigation there was a Section 173 agreement between council and Melb water about flooding and all these extra conditions. Turned out the block was immediately adjacent to the main stormwater drain and the building had to cover the expected 1 in 100 year flood. Took a lot of effort to get answers out of Melb water and the council so can't really help with anything other than ask all your questions twice! I got sick of conflicting information even after I'd requested the right material from landata. Including the floor height issue you mentioned, their requirements conflicted with the conditions they had set out so I walked way. Seemed fairly clear to me that the block should have stayed as a reserve. Re: Melbourne Water 1-in-100 year flood Special Building Overlay 7Apr 07, 2009 12:06 pm Love those 1/100 flood overlays, but they are there for a reason nearly brought a house with one of those overlays (was built before them thou) that needed to be renovated and my builder told me it would be too expensive to put a adition on with that overlay, so I choose not to buy, within 3 months of saying no the house was completely flood twice......... Re: Re: 8Apr 07, 2009 1:14 pm James Bond MrT Yep, we had to deal with this. Our floor levels have to be 100cm above the ground level, implying that the 100yr flood level is 70cm above the ground. This is patently absurd, and results from using computer modelling rather than any actual historical data. Mate, I have a question. How did your concreters know where to set the finished floor levels? We have a "TBM nail in bitumen" in other words a nail in the street which is at 5.26m above AHD, but the concreters doing the strip footings and garage slab have asked that to be translated into 6.05m on the fenceline. Also I have to make sure I get the FFL at 6.3m - what's the best way for me to make sure these levels are accurate? How did you do it? Thanks JB Builders / concreters probably use a simple dumpy level. If you were worried you could use a long piece of clear tube to act as a level. Measure up from the TBM either 0.79m or 1.04m and get the water in the tube to match this level. Then walk around with the other end to see where the relevant level (6.05/6.3) is. Your concretors obviously don't have the brains and/or equipment to do this so they want the level of 6.05m marked close to their works. (base of a 0.25m slab I'm guessing). Either way if its a serious issue, the slab level should be checked prior to pouring (by a surveyor). Re: 9Oct 20, 2009 11:00 pm MrT Yep, we had to deal with this. Our floor levels have to be 100cm above the ground level, implying that the 100yr flood level is 70cm above the ground. This is patently absurd, and results from using computer modelling rather than any actual historical data. In the end, we decided not to have a garage, as it would have been 70cm above the ground, with a massive amount of concrete in the front yard. When we asked why the garage had to be so high, we got reasons like: "So that the car doesn't float way. So that chemicals stored in the garage are not subject to flooding and entering hte waterway. In case anyone was to sleep in the garage." Instead, we have no garage, meaning a car is more likely to float away. Any paint/chemicals we have will now be stored under the house, making it much more likely that they'll end up in floodwater. Crazy stuff, driven by bureaucratic need to minimise risk exposure by Melbourne Water, who have chosen to transfer the cost of upgrading the waste water system onto householders, who have to add costs onto their building instead. Good luck with your negotiations - we managed to get some concession on the height of our garage floor, but it was still to high for us to bother with. I've heard stories where people were made to build a metre off the ground like us, but then were forbidden from bringing imported fill onto the site to make this possible, as it would change the runoff velocity - Catch 22! Question...???? You mention that you managed to get some concession on the height of your garage floor.....What sort on concession....or did they decrease the floor level by a number of mm....I am curious .....Regards Camry Re: Re: 10Oct 21, 2009 6:44 am camry Question...???? You mention that you managed to get some concession on the height of your garage floor.....What sort on concession....or did they decrease the floor level by a number of mm....I am curious .....Regards Camry In our case, rather than applying the same flood level across the whole block, they applied a graded flood level from the rear of the block (the highest) to the front of the block (the lowest). As we were building at the front of the block we could therefore lower the garage by about 150mm from memory. It made calculating levels rather hard though and I still don't know if I got it right so hopefully when we get the final inspection they don't make us rip the house down and start again. JB Re: Melbourne Water 1-in-100 year flood Special Building Overlay 11Oct 21, 2009 7:04 am Hi, We are trying to build in Sydney and I ask that you pardon my lack of knowledge in this area as we are so new to this.... Bottom line is that we are "flood prone" using the 1/100 year rating and we have had our FFL forcibly set by council as 46.08 on a single storey. Having said that though they were quite happy to "drop" the garage by over 400mm which was to do with the gradient of the drive. We think this may have been a crock as it would actually make the gradient steeper. Anyway - when we questioned why the garage was at the level we wanted for the whole house they gave us NO concession in the FFL and that because the garage was a uninhabitable it was OK. We are also subject to overland flow which is an entirely different matter but is being discussed in another thread. We have not had the words "overlay" used so this is a bit new but no doubt we will be familiar with it too. ML Re: Melbourne Water 1-in-100 year flood Special Building Overlay 12Oct 21, 2009 9:25 pm dave- James Bond Is anyone else subject to this Melbourne Water flood special building overlay? I looked at a property a while ago that already had plans and permits to build a couple units but upon further investigation there was a Section 173 agreement between council and Melb water about flooding and all these extra conditions. Turned out the block was immediately adjacent to the main stormwater drain and the building had to cover the expected 1 in 100 year flood. Took a lot of effort to get answers out of Melb water and the council so can't really help with anything other than ask all your questions twice! I got sick of conflicting information even after I'd requested the right material from landata. Including the floor height issue you mentioned, their requirements conflicted with the conditions they had set out so I walked way. Seemed fairly clear to me that the block should have stayed as a reserve. HELP-HELP on this issue: I am still trying to get some clarification with my case maybe you can help. My garage is built on a 100mm thick concrete slab. The land surveyor has advised that the FFL of the garage is 95.19m at the front and 95.20m at the rear.As per the planning permit the flood level is 95.3m related to AHD.The condition on the permit states that the FFL is to be 0.15m above the flood level,therefore the min FFL should be 95.45m.The FFLas constructed is 95.19m which is 0.26m below the required level.Can anyone suggest how I can approach Mel.Water on this....????...I have made one attempt in a detailed letter...maybe I can try another approach....What do you think...????afterall it is an unihabitable building located at the rear of my property....P.S....My first letter to Mel Water was not successful....I may have to refer my case to the Energy & Water Ombudsman...Has anyone tried this..???..... OPEN TO ALL SUGGESTIONS. Thanks Camry. Re: Melbourne Water 1-in-100 year flood Special Building Overlay 13Oct 22, 2009 6:44 am camry HELP-HELP on this issue: I am still trying to get some clarification with my case maybe you can help. My garage is built on a 100mm thick concrete slab. The land surveyor has advised that the FFL of the garage is 95.19m at the front and 95.20m at the rear.As per the planning permit the flood level is 95.3m related to AHD.The condition on the permit states that the FFL is to be 0.15m above the flood level,therefore the min FFL should be 95.45m.The FFLas constructed is 95.19m which is 0.26m below the required level. Did you build the garage after the planning permit was issued? If so, I suggest you rebuild your garage in accordance with your planning permit. If you ignore the conditions on your planning permit you can expect to be made to tear it down and start again until it meets the conditions! If the garage was not subject to the planning permit because it pre-dates it then it is none of Melbourne Water's business how high it is. JB Re: Melbourne Water 1-in-100 year flood Special Building Overlay 14Oct 22, 2009 1:07 pm Having just gone through this.... if the land has an SBO on it, you are not able to get building/planning permit without providing 3 copies of full plans plus elevations and height to your council and Melbourne Water. And those plans must comply with the 300/150mm + flood level for the site. So... once you have permits, you must build according to those permits. If you or your builder hasnt... well then you have a big problem. To end up with the levels below the AHD as required by Melb Water, means someone didnt follow the rules. I expect the council is within their rights to have the house knocked back down if it doesnt comply with the requirements of the permits. My block has a flood level of 36.45 and Henley have been very good at planning the slab to fit within the rules and as such the permits are all done now. Building - Henley Ambassador 483 - 15m Status - Post contract plans & siting. Blog & photos - http://fromgotowhoa.blogspot.com/ Re: Melbourne Water 1-in-100 year flood Special Building Overlay 15Oct 29, 2009 7:07 pm James Bond camry HELP-HELP on this issue: I am still trying to get some clarification with my case maybe you can help. My garage is built on a 100mm thick concrete slab. The land surveyor has advised that the FFL of the garage is 95.19m at the front and 95.20m at the rear.As per the planning permit the flood level is 95.3m related to AHD.The condition on the permit states that the FFL is to be 0.15m above the flood level,therefore the min FFL should be 95.45m.The FFLas constructed is 95.19m which is 0.26m below the required level. Did you build the garage after the planning permit was issued? If so, I suggest you rebuild your garage in accordance with your planning permit. If you ignore the conditions on your planning permit you can expect to be made to tear it down and start again until it meets the conditions! If the garage was not subject to the planning permit because it pre-dates it then it is none of Melbourne Water's business how high it is. JB What do you mean by.....if the garage was not subject to the planning permit because it pre-dates.......???? The building permit was issued after the planning permit... /////// /////////////////////////////////////////////////////// Re: Melbourne Water 1-in-100 year flood Special Building Overlay 16Oct 30, 2009 7:38 am camry James Bond camry HELP-HELP on this issue: I am still trying to get some clarification with my case maybe you can help. My garage is built on a 100mm thick concrete slab. The land surveyor has advised that the FFL of the garage is 95.19m at the front and 95.20m at the rear.As per the planning permit the flood level is 95.3m related to AHD.The condition on the permit states that the FFL is to be 0.15m above the flood level,therefore the min FFL should be 95.45m.The FFLas constructed is 95.19m which is 0.26m below the required level. Did you build the garage after the planning permit was issued? If so, I suggest you rebuild your garage in accordance with your planning permit. If you ignore the conditions on your planning permit you can expect to be made to tear it down and start again until it meets the conditions! If the garage was not subject to the planning permit because it pre-dates it then it is none of Melbourne Water's business how high it is. JB What do you mean by.....if the garage was not subject to the planning permit because it pre-dates.......???? The building permit was issued after the planning permit... /////// /////////////////////////////////////////////////////// Then you will have to rebuild your garage as it hasn't been built to the conditions of your planning permit, by the sounds of it. JB As is per usual for many of the past failed RWH regulations, it is probably traceable to a bureaucrat who's ego overrode the need to seek the appropriate expert… 1 1024 Give Jonathan a call. Tell him you know me. He is in my opinion the best surveyor I have ever worked with. His number is 0425 285 622 All the best Simeon 3 12423 Yes it had a house on it. But Melbourne water only wanted something the original size of the existing house. We managed to fit a 45sq house on. 10 33668 |