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Does CDOT use only SMS or RAS and SWMM 2D?

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Afternoon all!

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Please give us feedback as well -- the Colorado DOT has lots to learn from our partners across the U.S.!!

can you share your slides with the group, this is something that would be very beneficial.

How do you get topographic information that is sufficient for a 2D model for a 10-20 hour effort quick check?

@nickvivian their slides should be in the pdf download Scott posted early in the chat. Are you able to access it?

I don't see the slides either

I think older Chat posts are now off the board.

I apologize I came in late. can you repost?

Good to know it's only available based on when you join...still learning here

Laura, I got them. Download successful. Thank you

For the projects that you have performed a 2dQC on (and possibly those for which you haven't), will you be requiring that design consultants adopt and advance the 2D models as part of the design process at some point in the future?

Encouraging but not necessarily requiring

More guidance will be shared shortly on when 2D might be helpful, and when it might not be

For anyone who hasn't checked out the CDOT Risk and Resiliency manual, it's very well-detailed and helpful for BCA's involving CDOT infrastructure: https://www.codot.gov/programs/planning/assets/cdot-rnr-analysis-procedure-8-4-2020-v6.pdf

Colorado DOT Resiliency Program splash page:https://www.codot.gov/programs/planning/cdot-resilience-program

Contact for Colorado DOT Resiliency = Lizzie Kemp, Elizabeth.Kemp@state.co.us

Thank you for sharing.

what do you use for your flow hydrograph?

Was this Red Mountain Pass model conducted in SRH-2D or RAS2D?

Red Mtn Pass was SRH-2D with SMS interface

Hydrology generally developed with WMS & HEC-HMS using NOAA Atlas 14 methods for all of these projects

so then was hydrology included in the 3 hrs or 3 hrs was 2D only? curious about level of effort for the hydrology vs hydraulics on the quick check process.

Are you making assumptions on channel bathymetry for these quick checks?

Do you have Lidar for whole state? how do you get terrain for quick check models before scoping and survey?

Did you use LiDAR data to build your quick check MESH?

Statewide LiDAR in Colorado:https://coloradohazardmapping.com/lidar

Have you had any quick checks where the results didn't significantly match the final model?

Were resource agencies critical of the alternatives thah that that optimized culvert/bridge sizes?

I stutter!

Great question Laura!

How did you identify which projects were candidates for the 2D quick check within the region?

Can they share a typical report?

This is fantastic, very well done. This is exactly what executives want to see and will help states institutionalize 2D modeling.

What effort is being use to develop the hydrology.

why is CDOT's average time and cost so much lower than the consultants?

Did you consider adding longitudinal encroachments to the matrix?

Lisa, our time is lower because of (1) low overhead costs, and (2) internal staff experience

I think it's really important to point out it's about more than just cost savings

Kalli, can you share that best practices summary with this group?

Does CDOT have a preference regarding what software is used for 2D analyses? Why do you prefer SRH-2D over HEC-RAS 2D/SWMM 2D/FLO-2D etc.?

We prefer to use SRH-2D in house but will accept 2D software analyses from all sources

It sounds like the available LiDAR really opens up the quick check opportunities. State- (or even County) wide LiDAR is certainly on our wishlist here in AZ

Yes, we are grateful to work in a LiDAR data-rich environment

I love the idea of having hydraulic models and additional information being available through state GIS for everyone to see

These course deliverables would be great to share with the industry.

Setting up an H&H foundation for future projects cuts 10% off the total pre-construction design cost of all projects Colorado DOT delivers statewide

We are authorized to share our training materials with any DOT -- reach out to us

Brian V, that's a helpful tidbit that can help us sell the idea to ADOT - thanks

Big thanks to CDOT for that!

A quick check course. Awesome. Where can I find it.

That would be very helpful!

Brian V, would the training materials be able to be shared with consultants as well, or only DOT's?

We can share our training material with everyone, thanks to our national and state tax payers!

Did you have to make assumptions for bathymetry below normal water that LiDAR doesn't see or use LiDAR information as is?

Where does Quality Control go in the process workflow? How much time is typical for review and revision of these 2dQC models?

QA being developed now, QC embedded by crossing the in-house/consultant line. Consultants reviewed our in-house work and we reviewed theirs until all parties were at consensus on results, conclusions and recommendations

We also trade analyses across Region boundaries for QC & QC at Colorado DOT. The FHWA Resource Center was gracious in helping with QC on major projects as well (especially those involved in litigation)

I bet that made your bridge engineers happy!

To NTM Philly's question on LiDAR and bathymetry... most of our waterways are ephemeral or shallow channels, so we can often ignore bathymetry, but on canyon areas where depth matters, we use actual survey bathymetry collected during low flow seasons.

If lidar is not available, has DEM 10 proven valuable for the 2dQC models?

DEM 10 has not proven valuable for a 2d Quick Check in our state

Can you clarify on using 2D for a no-rise analysis? Can this take the place of using a1-D effective model for the no-rise analysis?

Jason Dayton, it depends... If I have a 1D regulatory model I will use it first and foremost

Did more detailed analysis/data collected subsequent to the 2DQC require significant alterations to the 2DQC recommendations on any of these projects?

Will deRosset, on some projects yes and some no. There are surprises everywhere and we cannot always predict them, but ever 2dQC reduces design and decision-making uncertainty

This has been very informative about your approach. Thank you.

Have you developed a hydraulic scoping policy?

We do not have a hydraulic scoping policy but it is on our wish list

I think it is important to highlight to everyone the response to the above question regarding the use of LiDAR in areas where ephemeral versus perennial streams are the norm. This is a very cool program for use in western states, but the lack of channel topography would greatly increase the cost of implementing something like this in a state like Pennsylvania during the project scoping phase. Any recommendations on this?

Emily - At the quick check stage creating an approximate channel would be sufficient. See page 4.24 in the 2D reference document.

You are correct, that to develop a final model with better channel data would require additional data.

thank you all! Gotta hop off

Thank you for all your support Marta!

Thanks you all!

Thanks, y'all!

Manning's number, Boundary Conditions, Cells sizes affect model accuracy and results significantly in 2D modeling. How do you account for that in a quick check?

Thanks everyone!!

Thanks All, helpful perspective.

Thanks!

Great Job! Thanks for sharing your findings

Thank you all!

Great thank you so much

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Thank you!

Thank you!

Thank You. Nice to see you again!

Thanks all!

Thank you!

Thank you!

thank you

Thank you all for your interest!

Thank you!

Thanks!

Excellent presentation and information. Thanks so much for sharing!