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What's a good design for a water intake from a stream?

I've stayed at several small communities that get their water from a stream. Everywhere I've stayed that intakes surface water has had issues. Sometimes the pipes get clogged. If there's filters, the filters get clogged and when it rains hard, the intake gets flooded with organic matter (e.g. leaves, sticks). So every time it rains hard, water stops flowing until someone goes to manually remove the debris in order to unclog the intake.

I know that large-scale systems (e.g. power plant cooling) use active solutions (i.e. mechanical systems requiring energy) such as a traveling screen.

But I'm specifically looking for small-scale (e.g. 1,000 liters intake per day) to medium-scale (e.g. 10,000 liters per day) passive (i.e. no moving parts) solutions.

What clever passive raw water intake solutions can be built for a small-to-medium sized off-grid house/community that minimizes required maintenance in turbid surface water collection?

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The best intake solution I have seen used is the Aquashear intake based on the Coanda effect.

The water rushes over the top and some sticks to the bars and drops while the rubbish carries on.

I saw it in use to feed a small (2kw) hydro-electric system in a wood which blocked so often with leaves it was sad. Then the aquashear was fitted and the owner only needed to clean about once a month and so little even he could not believe it.

There is no reason why it could not be employed to supply drinking water systems and it has no moving parts and can easily supply the capacity.

See enter link description here

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  • $\begingroup$ Coanda effect screens are described simply in this 14-page document titled Tools to Support Design of Coanda-Effect Screens for Debris Exclusion and Fish Protection published by the USA Bureau of Reclamation $\endgroup$
    – Michael Altfield
    Commented Nov 9, 2023 at 1:20
  • $\begingroup$ Coanda effect screens are described in-detail in this 44-page document titled DESIGN GUIDANCE FOR COANDA-EFFECT SCREENS published by he USA Bureau of Reclamation. For photos of example installations, see pages 34-37 in the appendix. $\endgroup$
    – Michael Altfield
    Commented Nov 9, 2023 at 1:22
  • $\begingroup$ SolarMike, can you please add some detail to your answer about wedge-wire screens and the specific wedge-wire screens used in coanda-effect screens (how the wedges are titled 3-6 degrees to create a wire tilt angle that dramatically increases passing of water through the screen via the coanda-effect). Adding images of the schematic of the design of coanda-effect screens and photos of the actual screens would be very helpful. $\endgroup$
    – Michael Altfield
    Commented Nov 9, 2023 at 1:49
  • $\begingroup$ @MichaelAltfield the link provides information on the use and sizing. I did not intend to provide any information about designing the screens themselves - but you seem to have covered that in your comments. That info may make a better answer to a different question. $\endgroup$
    – Solar Mike
    Commented Nov 9, 2023 at 5:31
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Best strategy is a progressive sieve filter. enter image description here

Uses mesh various sizes to capture progressively smaller matter. The bigger filters catch debris that's easy to dispose of without knocking whole filter out of service. enter image description here You may also try idea IF you have sufficient stream flow a water wheel with a mechanical arm to push a scrapper to remove debris from the filter.

Final strategy is build a venetian well. Pinnacle clean water tech, minimal power. System uses captured water thru a filtration medium which collects bottom of a well. Then harvested. If you build one to permit the stream to flow into the well and gravity fed enter image description here

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  • $\begingroup$ Venetian Wells are fed by rain water and many laws were passed to keep the squares where they sat very clean. Sand filters clog fairly easily, so I don't think a Venetian Well would be a good option for collecting turbid surface water with lots of debris. $\endgroup$
    – Michael Altfield
    Commented Nov 9, 2023 at 2:15

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