[SEL] O.T. O.T. Need Help On Water Flow Problem

[curt at rustyiron.com]

Paul,
You got the answer you needed from Kevin Armstrong in Oz concerning area
of the header and combined area of the small holes.
My garden rows are straight and about 40' long. Years ago I made an
irrigation pipe to quickly (why soaker hoses are useless) irrigate each
row. Made the 40' length of 1" PVC pipe. I drilled a hole every foot, so
there were 40 holes. The holes are all 1/8" diameter. The total area of
the 40, 1/8" holes is about 1/2 of the cross sectional area of the 1" PVC
header. This irrigation pipe works beautifully. I put the pipe on a row,
run it a few minutes until water is puddling, and then pull the pipe 6"
and let it run another few minutes. I have the same 5 GPM source you have.
Someone mentioned 1/16" holes. No good. Even with the 1/8" holes, I
occasionally have to take a pine needle or something and "rod" a few of
the holes to re-establish good flow.

You are close on your 230. It is 231 cu inches to the gallon. 1 gallon
will cover 230 SQUARE inches to a depth of 1"

In summary, make your header out of large diameter pipe (1") and the holes
small (1/8"). Don't worry so much about the time. Just hook up the hose,
and by the time you've finished a cold one, your 'mater roots will be wet
enough.

Last, you might consider turning the holes up. I run mine this way so you
have an instant visual if a hole is partially plugged. In your case, a
rectangular header as I recall you said, it will also make cleaning out a
plugged hole much easier. The water spurts up about 10 to 12" at the most
Curt Holland
Gastonia, NC
P.S. All this assumes your garden plot is level.


> Thanks Bob.
>
> I have been told that 1 gallon of water will cover 230 cubic inches to a
> dept of 1". I measured my water flow from the end of the hose coming from
> my
> water faucet and it is 5 gpm per minute. I know that my actual bed size is
> 117.5" X 39.5" or 4641.3 cubic inches of soil surface. 1 gallon of water =
> 230 ci so I divide my total soil surface of 4641.3 by 230 which = 20.1
> gallons of water needed to achieve a water penetration depth of 1" over my
> soil surface. Knowing that my flow rate is 5 GPM/minute I now divide the
> 20.1 gallons needed by 5 gpm/min (actual flow rate) and find I would need
> to
> leave the water on for 4 minutes in order to achieve a 1" depth of water
> penetration over the bed area.
>
> In order for this to work I will need to get an equal flow out of each of
> the dispensing holes or some parts of the bed will get more and some get
> less of the water. This is my problem, trying to achieve an equal amount
> of
> water out of each orifice.
>
> Paul
>
>
> ----- Original Message -----
> From: "Bob Willman" <blcksmth at wcnet.org>
> To: "'The SEL email discussion list'" <sel at lists.stationary-engine.com>
> Sent: Tuesday, June 02, 2009 10:21 PM
> Subject: Re: [SEL] O.T. O.T. Need Help On Water Flow Problem
>
>
>> I would think that very very small holes at the 16 locations so that
>> the water flow from each is a very small percentage of the flow in the
>> main
>> pipe so as to maintain constant pressure throughout the system. As it is
>> the
>> pressure drops after each discharge hole. You could start with a larger
>> diameter pipe up front and reduce the diameter after each opening which,
>> I
>> think, is the accepted method.
>> If all the holes are already drilled and the system is level, I
>> would try turning all the discharge holes to the top of the pipe and use
>> a
>> very slow flow rate in order to fill the entire pipe and let it slowly
>> run
>> out over the pipe to keep the flow rate slow but hopefully stabilize the
>> pressure along the whole length.
>>
>>
>> Bob Willman
>
> _______________________________________________
> SEL mailing list
> SEL at lists.stationary-engine.com
> http://www.stationary-engine.com/mailman/listinfo/sel
>