Hi,
What is the absolute minimum fall land should have for sufficient rain water drainage?
Thanks.
What should land fall be for drainage?
Page 1 of 1
Do you mean land slope for open surface drainage or pipe slope for subsurface stormwater drainage?
[quote="SaveH2O"]Do you mean land slope for open surface drainage or pipe slope for subsurface stormwater drainage?[/
I would love to know both please. Thanks
I would love to know both please. Thanks
Subsurface stormwater minimum pipe slopes (in Australia) with nominal diameters of:
90mm, 100mm and 150mm-- 1:100.
225mm-- 1:200.
300mm-- 1:250.
375mm-- 1:300
It has to be noted that stormwater pipes also drain surface areas and silt pits but stormwater pipes are most often annexed for use as rainwater harvesting wet system/charged pipes. Charged pipes do not need a slope but the plumbing code hierarchy is as below:
Building Act
Plumbing regs 2018
NCC series- The Plumbing Code of Australia (PCA) is Vol 3.
Referenced docs, for example AS 3500.3
When it comes to rainwater harvesting and the definition of stormwater within the above layers of hierarchy, the regulations are an archaic hierarchal mess that do not clearly and uniformly define a difference between stormwater and water collected off non trafficable roof areas for the purpose of rainwater harvesting.
I know that your 'stormwater' pipes are used to transfer harvested roof water to water tanks but if you are asking about their required slope, then that is a lengthy discussion with a lot of current unresolvable turns and twists that I don't wan't to become involved with except to say that I believe that a charged pipe transfering harvested roof water to a tank does not require a slope.
Re slope for an open drain, obviously exposed water should not be allowed to pool and this requires an open drain to have some slope. Surface channels need to have design flows that accounts for the total areas of the ground surfaces and other surfaces drained and their run off coefficients, the region's applicable rainfall intensity and of course the drain's cross sectional area and the slope required to meet the required design capacity. I don't know whether there is a minimum applicable slope requirement.
90mm, 100mm and 150mm-- 1:100.
225mm-- 1:200.
300mm-- 1:250.
375mm-- 1:300
It has to be noted that stormwater pipes also drain surface areas and silt pits but stormwater pipes are most often annexed for use as rainwater harvesting wet system/charged pipes. Charged pipes do not need a slope but the plumbing code hierarchy is as below:
Building Act
Plumbing regs 2018
NCC series- The Plumbing Code of Australia (PCA) is Vol 3.
Referenced docs, for example AS 3500.3
When it comes to rainwater harvesting and the definition of stormwater within the above layers of hierarchy, the regulations are an archaic hierarchal mess that do not clearly and uniformly define a difference between stormwater and water collected off non trafficable roof areas for the purpose of rainwater harvesting.
I know that your 'stormwater' pipes are used to transfer harvested roof water to water tanks but if you are asking about their required slope, then that is a lengthy discussion with a lot of current unresolvable turns and twists that I don't wan't to become involved with except to say that I believe that a charged pipe transfering harvested roof water to a tank does not require a slope.
Re slope for an open drain, obviously exposed water should not be allowed to pool and this requires an open drain to have some slope. Surface channels need to have design flows that accounts for the total areas of the ground surfaces and other surfaces drained and their run off coefficients, the region's applicable rainfall intensity and of course the drain's cross sectional area and the slope required to meet the required design capacity. I don't know whether there is a minimum applicable slope requirement.
Subsurface stormwater minimum pipe slopes (in Australia) with nominal diameters of:
90mm, 100mm and 150mm-- 1:100.
225mm-- 1:200.
300mm-- 1:250.
375mm-- 1:300
It has to be noted that stormwater pipes also drain surface areas and silt pits but stormwater pipes are most often annexed for use as rainwater harvesting wet system/charged pipes. Charged pipes do not need a slope but the plumbing code hierarchy is as below:
Building Act
Plumbing regs 2018
NCC series- The Plumbing Code of Australia (PCA) is Vol 3.
Referenced docs, for example AS 3500.3
When it comes to rainwater harvesting and the definition of stormwater within the above layers of hierarchy, the regulations are an archaic hierarchal mess that do not clearly and uniformly define a difference between stormwater and water collected off non trafficable roof areas for the purpose of rainwater harvesting.
I know that your 'stormwater' pipes are used to transfer harvested roof water to water tanks but if you are asking about their required slope, then that is a lengthy discussion with a lot of current unresolvable turns and twists that I don't wan't to become involved with except to say that I believe that a charged pipe transfering harvested roof water to a tank does not require a slope.
Re slope for an open drain, obviously exposed water should not be allowed to pool and this requires an open drain to have some slope. Surface channels need to have design flows that accounts for the total areas of the ground surfaces and other surfaces drained and their run off coefficients, the region's applicable rainfall intensity and of course the drain's cross sectional area and the slope required to meet the required design capacity. I don't know whether there is a minimum applicable slope requirement.
90mm, 100mm and 150mm-- 1:100.
225mm-- 1:200.
300mm-- 1:250.
375mm-- 1:300
It has to be noted that stormwater pipes also drain surface areas and silt pits but stormwater pipes are most often annexed for use as rainwater harvesting wet system/charged pipes. Charged pipes do not need a slope but the plumbing code hierarchy is as below:
Building Act
Plumbing regs 2018
NCC series- The Plumbing Code of Australia (PCA) is Vol 3.
Referenced docs, for example AS 3500.3
When it comes to rainwater harvesting and the definition of stormwater within the above layers of hierarchy, the regulations are an archaic hierarchal mess that do not clearly and uniformly define a difference between stormwater and water collected off non trafficable roof areas for the purpose of rainwater harvesting.
I know that your 'stormwater' pipes are used to transfer harvested roof water to water tanks but if you are asking about their required slope, then that is a lengthy discussion with a lot of current unresolvable turns and twists that I don't wan't to become involved with except to say that I believe that a charged pipe transfering harvested roof water to a tank does not require a slope.
Re slope for an open drain, obviously exposed water should not be allowed to pool and this requires an open drain to have some slope. Surface channels need to have design flows that accounts for the total areas of the ground surfaces and other surfaces drained and their run off coefficients, the region's applicable rainfall intensity and of course the drain's cross sectional area and the slope required to meet the required design capacity. I don't know whether there is a minimum applicable slope requirement.
That's very helpful, thank you. I was mostly interested in knowing if a spoon drain requires a specific slope, but I appreciate the extra information.
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