Thistle is one tough plant. We had a stone drive and had it paved two years ago. The thistle pushed up through 3" of asphalt and started trying to keep the drive as their home. Tordon RTU worked on mine.
They get bigger...I documented it in the 2023 Morel thread...they grew for about 2 week to 3 weeks...probably got 4 times their original size before starting to dry and brown.
May grow longer given the right conditions (rain).
I know you asked about the White River but might I suggest Fall Creek?
With everyone and their brother now having jet drive boats the White River gets a LOT more pressure than it used to.
Fall Creek has some quality 4lb+ smallies in it and gets WAY LESS pressure. It is also a good wading...
Commercial and Mulit-Family. Lots of apartment complexes, more Starbucks than I care to admit, and larger apartment buildings in and around downtown Indy. I am sure you have seen my projects in your travels.
Could be neighbors. Sounds like you are in the excavation business also?
We have just had more problem with socked under drains that regular perforated under drains with #8 stone back fill. Also if you thing about the millions of miles of under drains in farm fields...NONE of them are...
I have found socked under drains to be non-effective. They plug and no longer serve the purpose. Also socked under drains are a perforated pipe...you don't want perforated pipe...you want solid wall pipe.
Make sure to staple down the erosion blanket with blanket staples ALL over. If it doesn't make good ground contact the grass will tent the blanket off the ground defeating the purpose.
As for the pond wash out area. Anything you can put in there to break up the energy of the water will work. As shown in the post above brush and trees would work also. It slows the water down so it doesn't pond the dirt as hard. It also allows small areas for the natural vegetation the take root...