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Thread: Gutter calculator

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    Gutter calculator

    Hi guys,

    I'm an Architect. I have a raised overflow pool in my project with approximately 200,000 gallons of water. Yes, it's massive.
    We need to make our pool looks as if it's floating. So we're working on hiding the gratings to be a minimal slot hidden under the pool's stone edge.

    The question is how we can calculate the gutter size hidden under the stone finish deck? We're afraid that while the pool is splashing with huge amount of water _since too many users will be using it_ that the gutter won't be sufficient and the water might come out again out of the drain slot.
    26,660 gallon IG; plaster; 16x32 Rectangular, Depth 3Ft-8Ft.
    Hayward Pro-Grid DE Filter - 48sqft w/ cellulose fiber
    Hayward Energy Flo RS Pump
    Very old 312sqft solar system

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    Join Date
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    Mesa, Arizona
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    Re: Gutter calculator

    You can calculate gutter flow rate the same as if you were using pipe.

    This link has a nice calculator for estimating: http://www.1728.org/flowrate.htm

    Your biggest challenge will probably be applying an estimated number as to how much spillover at peak times you will be getting......
    Mesa, AZ Spillover spa and inground pool, 12,500 G, pebble finish, Hayward C5030 (525sf) Cartridge Filter, Hayward EcoStar VS Pump, Installed July 2013, Hayward SWG T-Cell-15, Trident UV (I know, I know....was installed before I found this site!) Rock grotto waterfall, LED ColorLogic lighting, 110 BTU Heat Pro Electric Heat Pump, Maytronics Dolphin Supreme M5 cleaner, TF-100 test kit with Speed Stir.

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    In the Industry

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    Re: Gutter calculator

    Isn't there a reserve tank for over flow pools to hold execss water when bather load is high and water is displaced? When bather load is reduced the reserve lets water Back into the pool. I forget the technical term.
    In ground 25,000 gallon - vinyl liner - Sand filter - residential pool
    Also maintain two commercial 190,000 gallon competitive indoor bromine facilities -9x Sand filters

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    mas985's Avatar
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    Re: Gutter calculator

    You can use the weir formula. That associates the depth of the water over edge with the length of weir to estimate flow rate. This is what is used for waterfalls. I have the formulas programmed into a tab of the Pool Tools spreadsheet located here:

    hydraulics-101-have-you-lost-your-head-t915.html#p6544

    Background:

    http://www.engineeringtoolbox.com/weirs ... d_592.html

    But keep in mind that the flow rate is dependent on the thickness of the water over the edge so it is basically an infinite range.

    If you need to calculate the volume of the gutter, that is a different problem. The way I would approach it is to the average volume of body (~20 gallons) and assume maybe 10 people jump in the water at once (~200 gallons). So if you build the gutter to handle twice that or maybe 500 gallons (67 cu-ft), you should be fine.

    How long is the gutter/edge?
    Mark
    Hydraulics 101; Pump Ed 101; Pump/Pool Spreadsheets; Pump Run Time Study; DIY Acid Dosing; DIY Cover Roller
    18'x36' 20k plaster, MaxFlo SP2303VSP, Aqualogic PS8 SWCG, 420 sq-ft Cartridge, Solar, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater

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    Re: Gutter calculator

    Quote Originally Posted by danjaymor
    You can calculate gutter flow rate the same as if you were using pipe.

    This link has a nice calculator for estimating: http://www.1728.org/flowrate.htm

    Your biggest challenge will probably be applying an estimated number as to how much spillover at peak times you will be getting......
    Thanks Danjay. But I guess it's a bit far as an estimation. I tried solving for a pipe diameter and I entered the perimeter of the pool as a velocity in feet/second, then I estimated the water flow rate as 500 gallons (67 cubic feet) as mas985 advised estimating that 10 persons jumped into water at the same time. The answer was almost 13cm.

    I donno how much that is close to reality.
    26,660 gallon IG; plaster; 16x32 Rectangular, Depth 3Ft-8Ft.
    Hayward Pro-Grid DE Filter - 48sqft w/ cellulose fiber
    Hayward Energy Flo RS Pump
    Very old 312sqft solar system

  6. Back To Top    #6

    Re: Gutter calculator

    Quote Originally Posted by Zadd
    Isn't there a reserve tank for over flow pools to hold execss water when bather load is high and water is displaced? When bather load is reduced the reserve lets water Back into the pool. I forget the technical term.
    Yes Zadd, but I need to calculate the the gutter diameter/cross section before reaching the tank.
    26,660 gallon IG; plaster; 16x32 Rectangular, Depth 3Ft-8Ft.
    Hayward Pro-Grid DE Filter - 48sqft w/ cellulose fiber
    Hayward Energy Flo RS Pump
    Very old 312sqft solar system

  7. Back To Top    #7

    Re: Gutter calculator

    Quote Originally Posted by mas985
    You can use the weir formula. That associates the depth of the water over edge with the length of weir to estimate flow rate. This is what is used for waterfalls. I have the formulas programmed into a tab of the Pool Tools spreadsheet located here:

    hydraulics-101-have-you-lost-your-head-t915.html#p6544

    Background:

    http://www.engineeringtoolbox.com/weirs ... d_592.html

    But keep in mind that the flow rate is dependent on the thickness of the water over the edge so it is basically an infinite range.

    If you need to calculate the volume of the gutter, that is a different problem. The way I would approach it is to the average volume of body (~20 gallons) and assume maybe 10 people jump in the water at once (~200 gallons). So if you build the gutter to handle twice that or maybe 500 gallons (67 cu-ft), you should be fine.

    How long is the gutter/edge?

    Thanks mas985. I guess what you meant to download is the pool pump tools going for waterfalls tab.
    Forgive the dummy part of me. I have four inquiries. First, why there is four cells infront of each parameter. Second, is the 'Edge width' will be considered as the pool perimeter. Third, Is the edge depth meant to be the thickness of the ledge. Last, Shall I consider the height between the pool edge and the slot channel as the height above water line.
    I guess this will give me the flow rate per minute/second.

    I need to determine the volume of the gutter. So do you think that if estimated the number of people and applied the amount of the excess water occurred as the gutter volume capacity. do you think it can work in that way.


    The pool perimeter is ~ 138m almost 460 feet.
    26,660 gallon IG; plaster; 16x32 Rectangular, Depth 3Ft-8Ft.
    Hayward Pro-Grid DE Filter - 48sqft w/ cellulose fiber
    Hayward Energy Flo RS Pump
    Very old 312sqft solar system

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    Join Date
    Jul 2013
    Location
    Mesa, Arizona
    Posts
    86

    Re: Gutter calculator

    Since you are going to be working with industry standard equipment sizing, these guys may be able to help you:

    http://www.ndspro.com/drainage-systems/ ... y-overview
    Mesa, AZ Spillover spa and inground pool, 12,500 G, pebble finish, Hayward C5030 (525sf) Cartridge Filter, Hayward EcoStar VS Pump, Installed July 2013, Hayward SWG T-Cell-15, Trident UV (I know, I know....was installed before I found this site!) Rock grotto waterfall, LED ColorLogic lighting, 110 BTU Heat Pro Electric Heat Pump, Maytronics Dolphin Supreme M5 cleaner, TF-100 test kit with Speed Stir.

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    mas985's Avatar
    Join Date
    May 2007
    Location
    Pleasanton, CA
    Posts
    11,489

    Re: Gutter calculator

    Quote Originally Posted by moemen83
    I need to determine the volume of the gutter. So do you think that if estimated the number of people and applied the amount of the excess water occurred as the gutter volume capacity. do you think it can work in that way.
    If you are only interested in the gutter volume (depth), then there are a limited number of ways to determine that. I tried to think of a worst case for water displacement (10 people) and just used that as an estimate. 10 people is about 200 gallons and a trough that is 460 feet long needs to have an area of 9 square inches or 3"x3". So basically, if your trough is bigger than that, it shouldn't be an issue. They can't really make waves big enough. However, there could be over splash so you might make the trough wider than deep.
    Mark
    Hydraulics 101; Pump Ed 101; Pump/Pool Spreadsheets; Pump Run Time Study; DIY Acid Dosing; DIY Cover Roller
    18'x36' 20k plaster, MaxFlo SP2303VSP, Aqualogic PS8 SWCG, 420 sq-ft Cartridge, Solar, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater

  10. Back To Top    #10

    Re: Gutter calculator

    Thank you guys. really appreciated
    26,660 gallon IG; plaster; 16x32 Rectangular, Depth 3Ft-8Ft.
    Hayward Pro-Grid DE Filter - 48sqft w/ cellulose fiber
    Hayward Energy Flo RS Pump
    Very old 312sqft solar system

  11. Back To Top    #11

    Re: Gutter calculator

    Quote Originally Posted by moemen83
    Quote Originally Posted by Zadd
    Isn't there a reserve tank for over flow pools to hold execss water when bather load is high and water is displaced? When bather load is reduced the reserve lets water Back into the pool. I forget the technical term.
    Yes Zadd, but I need to calculate the the gutter diameter/cross section before reaching the tank.
    Ive had the same problem for my new pool - same deal as you, hidden gutter but Ive sorted the gutter issue by planning to build shorter "lengths" of gutter, leading to "droppers" (4" dia) dropping into a 6" pipe with 1:100 fall.

    Pool builder has extensive experience in design and construction of large commercial pools and he says I should strongly consider using 8" dia pipe as he thinks the 6" wont be enough.
    Having said that, I think he was taking about 1, 8" dia pipe that travels around the entire perimeter of the pool (25m lap pool) to the catch tank, while Im planning on running the 6" pipes from the center of the far side (equipment is mount under ground, at the mid-line of one side) around each side, so I have 2, 6" pipes in effect.

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