Is this a terrible idea?

I have a 1 acre pond and a 3000sqft sediment pond that I try to use as a forage pond. The problem is that in a large rain event, a neighbors pond on the hill above overflows and I end up getting bass and bluegill fry or fingerlings washed into it and they seem to eat my minnows as they grow.

I was thinking of digging a small 100-200sqft "pond" to raise minnows that would be fed from runoff not the overflow from the neighbor. It would be near but above the other ponds. I have a small 6X8 depression there now that collects the runoff and sends it to the ponds. It fills up to around 6" deep before it can flow into the other ponds. All I would do is enlarge it and make it deeper. Maybe 2 or 3' deep.

The goal would be to simply breed some fatheads or shiners and then transfer the fingerlings into the larger ponds. If I could get a few shiners to breed I would have more fry than I could buy from Anderson minnow. I could also use it to breed PK shrimp to get them established in my large pond.

Worst case I would just end up creating a larger frog pond, best case it would help establish some forage in my other ponds.

I have a compact tractor that I would dig with. I think it would only take a 3-4 hours of time to dig it. I wouldn't be building a dam, just digging deeper hole. Soil is thick blue clay that doesn't drain and the spot already holds water year round.

Is this a worthwhile idea? Is it too small to work? It doesn't need to keep fish year round. How deep should it be?

My other thought was a 100-250 gallon stock tank fed by pond water, but I should be able to make this larger and with minimal investment other than my own time.

Thanks