Advise for planning underground irrigation piping system

Hi,

Some background:
We recently acquired a 32 acre farmland that has not been cultivated for past 30 years. Around 15 acres of it is dense forest trees (karimara in Kannada or firewood variety) and another 15 area is open flat fields once cultivated for paddy (I am told in 1990s). The farm was rainfed with no infrastructure to name except for DISCOM electric poles which enter the farm a few meters from the west side.

Since the time we acquired the land we have dug a shallow 120 * 60 feet rain water harvesting and fish cultivation pond (12-14 feet deep), a 20ft deep 25ft radius open well with a 120 head 5HP submersible (both close to the electric poles) and a good borewell with 4inch yield in the opposite side of the farm (but no electric line near it)

We plan to cultivate paddy in 2 acres on a trial basis for 2-3 years next to the pond and well (it tends to flood here about 6 inches) and the remainder tree-based 5-layer farming over stages. The plan is combination of natural and organic cultivation with a cattle shed in the property for organic inputs.

The question:
I need to immediately plan the pipeline from the 5HP pump of the open well to the under-construction house which is approx 125 meters away as the water is required for concrete mixing in about a month.

I am also contemplating a gravity-based irrigating system with a storage tank planned at the highest point of land near the borewell in the opposite corner of the land (well, house, borewell form a triangle). I might even want to keep an option open for connecting the 5HP borewell pump to the main line for rain gun operations. Solar pump setup with subsidies or traditional electric pump setup is not yet decided.

  1. What should be the size of the main pipe? Is 3inch PVC good enough? Will 4KG pressure rating suffice or should I invest in 6KG 3inch PVC? How do you calculate the requirement?
  2. How do I plan the valves for compartment irrigation and expansion in the future?
  3. Pressure release, air release, non-return, by-pass valve positioning etc
  4. What should be the ideal size of the main and lateral PVC pipes? Distance between laterals etc? How many L bends are tolerated?

Any good source for learning how to plan underground irrigation pipelines? Video or article or book?

I understand this is a very open ended questions so in case of any further questions please feel free to ask.

Thanks,
Ashwin

Better to take the help of any local Drop Irrigation Company Desine Engineer for Drip Designing, based on crop planning.
Regarding 3" pipe from the 5HP motor at well to house, with higher pressure (6psi) may be better, as the same source may have to be used for filling the Sub-surface Tank, Overhead Tank (with reduced pipe dia) on the proposed house and also to the Drip Irrigation

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Pressure drop calculation needs to be performed. you may take help of Drip irrigation company for the same. you can perform rough calculation yourself as well using excel sheet or google for readymade excel sheet with all formulae. this will help in working out optimal design with drip irrigation company.

Various tap-off outlets can be planned looking at contour map of your land and how much water is required at which location depending on crops planned. Future expansion can be taken care by having slightly bigger dia pipes at strategic segments.

This is part of system design, take help of drip irrigation company.

Each L-bend results in pressure drop. this all you can work out yourself with pressure drop calculation.
Please note that only gravity flow may not be adequate for drip irrigation pressure requirements. so plan before you execute. starts backwards — first check how much water storage is required for crops planned? ---- how much time is required to fill up calculated water storage capacity? – rather than starting from capacity of pump.
i am not expert on the subject, but have fair idea of how system sizing is done so this may help.
also from lifting water from lower elevation to higher elevation, you may plan solar PV pump.

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One of the best resource i found was online on YouTube.

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Thank you!