Editor:  A discussion ensued on finding a top for the raw water strainer where you could hook up a garden hose to blow out blockages.  Warren provided the following interesting approach:

I took another approach..found a special “expandable” plumbing fixture that works great…and is “dirt cheap”.

It’s called a “Mechanical Test Plug, with By-Pass”.  This is essentially a short pice of steel pipe [maybe a foot long] with a rubber “donut” attached to and surrounding the pipe, and has a large wing nut; the latter squeezes the rubber so that it expands, filling and sealing whatever its inserted into.

This is made in many sizes/diameters.  Our ID of top of strainer is 2″, so I bought test plug rated for 1.5 to 2.25″.,

Got mine from McMaster-Carr, p/n 2644K21, $8.17.     nj.sales@mcmaster.com is shown on p.o., but website available.

To make it easier to pour in a bucket or bottle of