Pond Boss Forums POND CONSTRUCTION Renovating a Pond or Lake? Silt catch pond repair

So as part of ongoing work to improve the water quality on my highly euthrophic pond, I need to repair one of the silt catch ponds. I was happy to have them already built by the original owner, but as with many other things, they fell into disrepair over the years. The background is: 2.5 acre pond, ave 8-9 feet in center, 2 feet in longest 'finger'. The silt catch pond dam needing repair feeds into that long finger. It is fed by an Ag tile across the road, and has water flowing year round. I have not tested it yet, but very likely this water is high in nitrates from Ag run-off, varying seasonally. The catch pond is approx 30 x 50 feet and has two 4 inch PVC pipes running through it's dam. The pipe on the woods side has developed a leak around it, and is beginning to excavate around the pipe. No doubt it will breech the dam if left another season.
Question: When having the dam repaired, would one central flow pipe work equally as well as two? Is having the pipe be a stand pipe the best idea? Is the depth of the catch pond critical for particulate settling? Or for nitrate reduction? Do nitrates even come down in concentration by sitting in the catch pond before entering the big pond? I'm thinking this is a major source of this pond's water quality issues, and since I'm tackling it this season, I would love to hear back from the collective wisdom of the PB forum.
I did 'do my homework' and read through the archives looking for similar problems and solutions, but nothing quite answered my questions.
Thanks fellas!
3 inches of snow over night here in southeast Iowa. Yuck.
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I've also attempted to find information on nitrate mitigation, and come up empty. Anyone with experience? I'm wondering if the catch pond IS the key step in this, but it may also have no impact.

I can't answer all your questions. But, from my research on natural swimming pools, the area that is needed to be in plants to clean the water (removing nutrients to facilitate clear swimming water in place of a mechanical filtration system and chemicals) needs to equal the area of the swimming pond. It also has to receive full sunlight for the plants to flourish.

I don't know if the retention time of the water in your catch pond would be long enough to lower the nutrient level enough to help. For a silt catch pond, I think it would work great. But, I don't know how much silt comes into your pond from the upstre4am side vs. the natural eutrophication process in your 2.5 acre pond. i.e. leaves, etc., and other silt washing in from the banks of the pond.

I've researched adding rooted plants to my pond, but have been leary so far. I worry about creating a control problem I didn't originally have. But right now, I have cattails along the main dam (and ONLY there, oddly enough) and lots of FA. I've wondered if planting that long finger with rooted plants wouldn't be the worst idea, given that it's too shallow at this point for much effective fishing.

Doc,

FWIW I look at rooted vegetation a little differently. You see, "I worry about creating a control problem I didn't originally have." I see, "creating habitat I didn't originally have." IMO when it comes to vegetation, you can choose desirable species and get them going or let Ma Nature fill the gap and take what you get. She will fill the gap given time.