To revisit a blast from the past, the t-posts were attempting to guard an 8" drain tile inlet. (Probably not too long after 2008) I replaced them with a commercially available wire guard, pretty much identical to these.

At my other pond, the drain box is surrounded (on three sides) by 1/2" plastic mesh (similar to plastic snow fence, but made for pond use), about 3" tall (submerged to the bottom of the pond tied on to (wait for it) t-posts. Having a much larger surface area than the drain box, it has been immune to clogging that would impede drainage (although this particular pond doesn't get a huge amount of floating debris.

"Live like you'll die tomorrow, but manage your grass like you'll live forever."
-S. M. Stirling
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