I have a small pond fed by a spring and stream above my house. There is a point where the stream passes under the road ( a dirt road ) and in extreme rain events, which we have had plenty of this year, the stream runs red with pure Pennsylvania clay. I have a small 'settlement pond' about 10 feet long by 6 feet wide which flows into a 4" pipe and enters my pond. In exceptionally heavy rains I can open an overflow valve and let the flow bypass the pond entirely. I constantly have to dig out sediment to keep the little settlement pond open. Are there any particular shapes which may enhance the settling (aside from making it an acre in size) or any tricks to trap more silt? I already have planted along the stream, and on the road side to catch as much sediment as possible so I'm wondering if there are any ways to enhance settling in the small trap.

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