Thread by @shayshinecastle

OK we're moving into the CU South discussion. So.... new thread.

We will be getting a look at tradeoffs, which are really smaller storm designs. But this is kind of Part 1 of 2, with a 3-hr study session planned for more in-depth discussion Feb. 25.

Here's the chart from the presentation:

There's really no other information in the presentation. So I'll pay attention and see if Joe Taddeucci,
Director of Public Works for Utilities, adds anything.

Variant 1 is the design we're working on. The intent is to prevent U.S. 36 from being "overtopped" by flood water, as happened in 2013, Taddeucci reminding the audience.

Former Boulder city council candidate Gala Orba is here. Haven't seen her since the election, though today she announced (via Twitter) her intention to become a two-term president of the United States.

The most striking thing about the tradeoffs, Tadeucci says, is the project costs, particularly "how quickly they go up" when designing for larger storms.

100-yr design: $67M
500-yr design: $110M

Tadeucci: "The reason for that is it transitions from dam and flood wall to an earth-moving project as well."

That's needed to build up the land enough so that CU can build on 129 acres, Tadeucci says, per their stated desire.

Crap, I spelled his name wrong the last 2 tweets. Taddeucci is correct.

All of the design options include $15M for "impacts to CU facilities."

Of course, the big thing that's changed in recent months (weeks, actually) is that CU is now saying that no matter which option of Variant 1 is chosen, they might not want to build housing there. boulderbeat.news/2020/01/26/cu-…

Yates: If no one was going to build on that land at all, would fill still be required?
Taddeucci: No
Yates: So fill is solely for the purchase of creating buildable land?

Taddeucci: Yes. The project guiding principles have cooperation with CU in there; they want 129 acres to build on.

Reminder (though I'm sure you all know this): This is CU's land. 308 acres. They are allowing Boulder to build flood mitigation on the land in exchange for being annexed into the city, giving them access to water, utilities, etc.

Taddeucci: The fill costs, in the 500-yr design, can be almost as much as the flood mitigation itself.

Wallach: Who prepared these cost estimates and how reliable do you believe them to be?

An engineering consultant, Taddeucci says (quietly. Speak up, man!)

Taddeucci: We're in the conceptual phase right now. "The cost estimates do have a margin of error of plus or minus 50%."

That margin will shrink as we get more detail on the project.

Wallach: The Dif between 100 and 500-yr design is protection for 800 homes. Do those homes see any benefit whatsoever from 100-yr design?

"They would see some benefit, I guess. The water stored in our reservoir, all of it wouldn't come downstream, so they might have more time to get out," Taddeucci says.

The 100-yr vs. 500-yr design is for the reservoir; the dam and flood wall have their own designation, Taddeucci says. That has to be for a "maximum probable flood," a FEMA designation. That's something an order of magnitude greater than the 2013 flood, I believe.

The dam and flood wall won't fail in a larger than 100-yr storm, Taddeucci says.

I was about to remind ya'll what 100-yr vs 500-yr means but I can't believe it: I've forgotten. I've been covering this topic for ~2 yrs and now I can't remember. Dam. (No pun intended.)

Young asking about water rights and flood flows.
Taddeucci: In a storm, where you're detaining water (in a reservoir) for a flood, you can only hold it for 72 hrs or 3 days. Typically, in a storm, nobody's worried about water rights. But it is a requirement of the state.

Would be interested to know if there's a workaround to that. Like an emergency exemption that Boulder could call and ask to not have to release water it is holding during a storm.

I'll let you know.

100-yr flood: $41M just for flood mitigation (the rest of the cost is fill.)
500-yr flood: $47M

That means the 500-yr has more than $60M worth of fill incorporated into the cost estimate.

Here's that chart again, for reference:

Those add'l numbers were from Taddeucci, btw.

Friend asking what benefit the 100-yr design offers.
"The whole time we're filling up that reservoir, that water is not flowing over the spillway," Taddeucci says. There is benefit to everybody having any flood mitigation there.

Taddeucci: "With the selection of this concept and the agreements put into place with the guiding principles. For our design team and consultant, our criteria was stick to those guiding principles."

These numbers are huge. The choice is now for Boulder to spent roughly $50M more than is strictly necessary for less flood protection just so CU can build there... and they might not even build housing.

Wild.

But, what else can Boulder do? They need CU's land for flood mitigation.

Would not be surprised to hear the idea of a land swap brought back up, especially given that the Area III planning reserve is (likely) being activated in coming years.

Brockett: One of the costs to this is the need to not move the tennis courts. Can we shift fill locations around so we don't have to rebuild those? Shift the fill area around on the site?

Taddeucci isn't sure: we've had the fill area here for quite some time. He'll check in and let you know.

Yates: Will the consultant's report be made public by the Feb. 25 study session?
Yes, is the long answer from Taddeucci. The draft was made available in January but it's changed considerably since then.

"It will be the foundation of the conversation on Feb. 25," he says. Plenty of time to review before a council vote in May.

Which is when this is supposed to come back for a "final" vote.

Friend wants more info on the homes downstream, from an equity standpoint. At least ID the affordable housing units, she asks.

And who we're "leaving hanging" depending on which design we go with.

Also wants to hear from CU RE: the letter I mentioned earlier. How can we still get housing there, she asks.

AND she brings up a land swap in the Area III planning reserve! "What is the normal timeline for" activating that planning reserve? How many years are we leaving ppl in harm's way if we go that route, Friend asks.

"We'll be prepared to speak to all those things," Taddeucci says, or let you know in advance if we can't.

Joseph: Do we even know if that's an option for CU? Why study something they won't agree to?

Weaver: We can do a 2021 urban services study for the planning reserve. That would tee it up for a 2025 approval.

Phil Kleisler, of planning, confirms.

The "approval" would really be reclassifying the land as Area II, making it eligible for annexation.

"Realistically," those areas wouldn't become available until 2026-2027.

Yates: "If we wanted to do something more aggressively ... what's possible?"

Housing division owns ~30 acres there; Boulder parks & rec owns ~193 or so.

Kleisler: I don't have the answer on how we might move more quickly, but I'll get the answer.

Reminder of where that land is: By the Gateway fun park (or whatever) north of town. There's a long-term lease there for Atlas tile and flooring, if that helps you orient yourself.

CU's Frances Draper speaking now. "I don't think we have anything at the moment" to share. "We have had some conversations about what we can do for housing and looking at a land swap. That's pretty much where it is."

Yates: Will you be presenting Feb. 25?
Draper: We haven't fully decided that yet.

Weaver: "For what it's worth, the 500-yr plan is the most cost effective per person protected."

Swetlik: Plus or minus 50%

Much laughter.

Jane Brautigam, RE: Friend's request for equity data on downstream dwellings.

We can get affordable housing data and data on critical care facilities, etc., she says.

Young asks for data on single-family vs. multi-family units.
Kleisler: We'll see what data is out there.
Brautigam: If the city owns the data, we can get it. If it's Census data or something, we can't bc we don't own it and it's not accurate.

Brautigam: "We will get all data that we can reasonably get."

OK, we're wrapped on this. Wow. Feels like a huge shift from where things had been heading.

@threadreaderapp please unroll. Thank you!