One of our bores is a Hitachi jet pump.

Every now and then, sand or small pebbles lodge in the water intake and stop the flap on the bottom of the pipe from closing, therefore all the pump water drains out and the pump won't pump as it has no head of water.

When this happens we have to lift up the 15m of pipe, clean out the debris so the flap will seal, then start again.

This is a pain.

I need to come up with a better solution.

The jet head is down the well at the bottom of the inlet pipe. 

Would moving the jet head to the top of the pipe near the pump motor make any difference?

Wrapping the ventuti and pipe inlet in some thin plastic gause?

Maybe replacing the jet pump with a conventional pump as the depth of pipe is only about 15m.

The pump is for back-up and irrigation, but Sod's Law states that everytime we go away something will happen to our other 60m main bore setup.

 

How far is the inlet from the bottom of the well / casing.

If it's close to or on the bottom of the well you stand the chance of entraining solids, lift it clear of the bottom. 

I try to have it 1m from the bottom, but the well water height and recharge rate varies between seasons.