Sounds like you'd want to build up the banks of the northern pond first so they'd at least be the same level of the southern pond. I don't if that could be done reliably enough to ensure it would hold water, though, or if you'd need to rebuild. Interesting idea, though.

Todd La Neve

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1.5 & .5 ac ponds - LMB, BG, RES, YP, GC, HSB