Thank you all for your perspective, examples and information! This stuff is amazing and I was able to use lots of it to back up what I wanted to communicate to the Board of Public Works. The real life examples are especially inspiring and encouraging to see. I apologize I haven't been keeping up with this thread better. Since I last posted, the Board of Public Works had their hearing and voted. Several of the board members heard and shared our serious concerns and questions. Two of five voted no, so there is a continuance! There will be another vote Wednesday. Apparently, this is an almost unheard of occurrence for something to not just sail through. So we've been researching, strategizing, writing a press release and emailing the board and others basically non-stop. Plus we're currently remodeling our house and trying to prep the garden for spring. So my brain is pretty much melted.
I didn't see this touched on above, but one of the major problems with a plan as proposed is that it will move the water downstream more rapidly, and increase the intensity of flood events downstream from you. This is why planners should be looking at whole watersheds, not simply play whack-a-mole with wherever the most intense problem is.
Here in the UK there are projects looking at whole watersheds that are both incredibly cost effective and environmentally friendly. For example, reforesting upland areas drastically reduces peak water flows during rain events. Frequently this is farmland that is, at best, marginal.
What Nature Does For Britain is an excellent book that looks at this, with other things. It is written from a UK perspective, but many of the lessons are universally applicable.
I wholeheartedly agree and have been repeating this point. There are multiple places down and upstream of us where there are flooding issues and this seems completely irresponsible to exacerbate them. I made the suggestion that a whole watershed approach was needed to truly address these problems at the last hearing. The engineer who's running this dismissed me, saying that was impossible except in very small, rural situations. I don't believe him. I also highly question whether the approach they are suggesting here (clear cut, sheet piling to bedrock and riprap on banks) would lead to landslides which could dam the river or at least, temporarily increase flood risk here by destabilizing the berm. The banks of the berm are very steep in places and currently well secured by trees. This seems like yet another serious problem set aside to "deal with later".
Book ordered! Looking forward to reading it.
Unfortunately, exacerbating the problem with these changing data points for weather (as you rightly point out) is the build up of cities, which causes water to drain more quickly into the watershed, exacerbating flooding. Can we fix that? We can help (permeable pavements, including catchment ponds in neighbourhoods, keeping wildlands, underground water catchment... etc), but it would take a big code change, and many years to retrofit (should we, is not a question asked here, but... I have some strong opinions on that one too).
I would be very interested to hear your thoughts on the question of "should we".
A few links that might be interesting for your discussions:
https://www.fema.gov/pdf/about/regions/regionx/Engineering_With_Nature_Web.pdf <- explanations on why riprap is bad, and plants are good, and some design information.
https://www.thespec.com/news-story/9100831-dead-christmas-trees-find-new-purpose-in-hamilton-harbour-wetlands/ <- a small scale project near me
http://www.dfo-mpo.gc.ca/Library/277708.pdf <- a Canadian guide for more natural stabilization.
Good luck! I really respect your determination to look deeper into this and try to find alternatives.
Thank you! These are gold! I especially like the last one. So many cool techniques!
Thank you again to all! Hopefully I shall have good news on Wednesday and our community can get to work on finding a sustainable solution instead of fighting this crazy plan! Prayers for the water welcome and appreciated!