Thread by @shayshinecastle

Mayor Brockett: There have been 2 fires today outside Boulder. Reminder that we're talking about fire resilience next week.

Some new renderings of what the flood mitigation project (dam, detention and floodwall) will look like.

That's U.S. 36 there

Coleman: This project is adjacent to state natural area, which as important wetlands and protected species. "South Boulder Creek has been ID'd as a unique ecological area within the state."

Lots of open space stuff was part of the annexation deal. Boulder will be gifted and purchase more than 100 acres for preservation. And have to give up a couple for the floodwall.

Alright, on to scheduling:
Environmental Permitting (Q2 2021 – Q4 2023)

FEMA Conditional Letter of Map Revision (Q2 2022 – Q3 2024)

OS-O Restoration Design (Q1 2022 – Q1 2023)

Stakeholder Agreements, including CDOT, CU, OSMP, and Dry Creek Ditch #2 (Q1 2015-Q3 2024)

And as far as design goes:
60% Design (Q2 2022 – Q1 2023)
90% Design (Q1 2023 – Q3 2024)

With construction to start in Q3 of 2024 through 2026(ish)

Here's a visual if you'd rather

It's nice because it also shows how many dif agencies have to sign off on this thing, including CDOT and FEMA and Colorado Parks and Wildlife and U.S. Fish and Wildlife. And and and...

Correction to earlier tweet: South Boulder Creek flooded in 1969, not 1069. (I mean, maybe it did in 1069, but I can't say for certain.)

https://twitter.com/shayshinecastle/status/1516584152836935685

Important to note on this timeline is when disposal will happen: mid 2023 to mid 2024 (roughly)

It won't take the whole year, Tadeucci says, naively.

The Open Space Board of Trustees has to sign off on this, as does city council. And there's a 60-day window for the public to do ... something. I'm not entirely clear what that is, but it will be a Big Deal.

"This is a really complicated process," Tadeucci says.

There's actually an open space disposal in tonight's CC packet. It was on the consent agenda. Of just 0.24 acres in a conservation easement, on a non-controversial project. So we do those routinely.

But I would expect this to not be routine.

Tadeucci addressing an open comment speaker who asked about cost estimates. Preliminary estimates were ~$41M, but staff has long noted that those could be off by up to 50% as they were very early stages.

We'll have more dialed in costs once we reach 60% design, Tadeucci says. (Middle of this year to early next)

Construction costs have increased, Tadeucci notes. We just bid a utilities project where our estimate was $18M, but the bid came in $4M over that.

That's what we need to be preparing ourself for, he says.

This project will be paid for by increasing storm and floodwater fees (on your city water bills). Boulder already has the highest rates on the Front Range, Tadeucci says — but we also have the highest flood risk.

Found what the 60-day public window is for disposal:
A petition signed by 5% of registered voters can force a vote of the people on the disposal (rather than just CC and OSBT OKing it)

That's what I thought, though I couldn't remember the number of signatures required. It's 5% at the time the petition is turned in; that number changes daily, but is roughly 3,200 today.

You can see the number of registered voters here. V cool! election.boco.solutions/CR_WebReportin…

Seems highly likely a petition will happen. There will be a question on ballots this year to undo the annexation; the result of a citizen petition.

Tadeucci: Any flood protection that we provide in any drainage will help the community. The question of what happens if a 500-yr flood comes and we only have 100-yr protection. People will still benefit downstream bc the flow will be less than if our project didn't exist.

Coleman: This gives us time to react, because we'll see it start to fill up before it overtops the spillway. That could help with emergency warnings. It's designed for a more critical event than the 2013 flood.

Friend: A 500-yr storm is not 5X the water of a 100-yr storm, correct?
Yes, Coleman confirms. He doesn't have exact numbers of how much bigger it is (though I bet I can find them from past presentations....)

Tadeucci: 100-yr protection is the most we have anywhere in the city, and most drainages are much less than that.

In case ya'll are new here and confused about the 100-yr and 500-yr terms, those refer to how likely a storm of a certain size are to occur in any given year. 500-yr bigger and more rare, though of course that might change given climate change.

Council doing that thing where they ask a lot of questions they already know the answers to in order to prove points.

Which means it's a good time to move on.

@threadreaderapp please unroll. Thanks!