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  • 1.  Retrofit Urban Stormwater Management

    Posted 10-19-2021 04:28 PM
    I am starting my 10 week "integrated project" course for my masters, and my focus is on retrofit solutions to urban stormwater management. 
    I've found a few case studies, but I was wondering if anyone could point me to any additional related case studies or maybe research/projects you have completed on this topic.


    Heidi C. Wallace, P.E., M.ASCE
    Tulsa, OK

  • 2.  RE: Retrofit Urban Stormwater Management

    Posted 10-20-2021 11:29 AM

    By retrofit, I assume you mean use much of what's already there, and modify it to perform better. If so, I offer an example of a project I worked on.

    In the 1980s, the 8.6 square mile community of Skokie, IL was faced with frequent surcharging of combined sewers which caused widespread basement flooding. The problem was viewed as stormwater out of control.

    The solution was to intentionally and temporally store stormwater on the streets. This was accomplished mostly with a system of mild cross-street berms and flow requlators in catch basins. 

    The successful solution cost 38% of the cost of the next best solution -- sewer separation.

    The project is described on pages 139-142 in my 2017 book Introduction to Creativity and Innovation for Engineers, Pearson.

    Hope this helps.

    Stu Walesh

    Stu Walesh PhD, PE
    Consultant - Teacher - Author

  • 3.  RE: Retrofit Urban Stormwater Management

    Posted 10-20-2021 12:35 PM
    Thanks! I'll have to check that out. 

    To clarify what I mean by retrofit: implementing or improving stormwater management in already urbanized areas (so your example would fit within that). A lot of times what we see in design suggestions are ideal cases for new construction, so I decided to focus on solutions for already urbanized cases. 

    What sparked my interest in this topic is the nearly non-existent stormwater management in the city where I'm currently studying. I'm used to designing a detention or retention pond for nearly all my projects, and we have an expansive network of storm sewers and channels back home. It's been strange here to see consistent street flooding with the normal rainy season events and very little storm infrastructure.

    Heidi C. Wallace, P.E., M.ASCE
    Tulsa, OK

  • 4.  RE: Retrofit Urban Stormwater Management

    Posted 10-25-2021 09:54 AM
    In the City of Austin, "retrofit" means to provide water quality treatment for previously untreated impervious cover.  We have built about 80 such projects since 1997.  However, based on this discussion, you seem to be asking about flood retrofits which is a very different situation. Be aware that there are profound geographic differences.  A 100-year storm in the upper Midwest might be equivalent to a 5-year storm in Texas or deep south. Also a local solution to keep people's feet dry in one neighborhood could be making matters worse downstream.  Robust and effective flood retrofits usually involve a lot of storage and are hugely expensive, particularly in wetter parts of the country where the flood volumes are large.  Cost-effective projects are often those where there was an existing hole in the ground and engineers found a way to divert the flood waters into it.

    Eric Loucks Ph.D., P.E., D.WRE, M.ASCE
    Supervising Engineer
    Austin TX

  • 5.  RE: Retrofit Urban Stormwater Management

    Posted 10-21-2021 07:54 AM
    You might want to look up Kevin Robert Perry at Urban Rain Design. He did a presentation at our local stormwater conference last year on what he calls tactical green infrastructure. Kevin's tactical green infrastructure focuses on low-cost solutions and rapid deployment which often involves volunteer labor or donated materials when implementing at places like schools or in communal areas. https://www.urbanraindesign.com/tactical-green-infrastructure-1

    Retrofits can be tough. I'm working on a few designs now, but am challenged with existing infrastructure, high groundwater (and it's salty), and high construction costs.

    Kristen Yoshida P.E., M.ASCE
    Belt Collins Hawaii LLC
    Honolulu, HI

  • 6.  RE: Retrofit Urban Stormwater Management

    Posted 10-21-2021 10:16 AM
    Thanks! I'll look into that!

    Heidi C. Wallace, P.E., M.ASCE
    Tulsa, OK

  • 7.  RE: Retrofit Urban Stormwater Management

    Posted 10-22-2021 08:50 AM
    Edited by Tirza Austin 10-23-2021 12:34 PM
    Heidi - You might be interested in checking out our project.  Starting in 1999 we had six presidential disaster declarations for flooding over a 12 year period in a 6.5 square mile watershed with 1,100 homes and businesses at risk.  After spending $139,000,000 we now have protection in place against a 500 year flood event.  We took a wholistic approach to flood mitigation by making improvements throughout the watershed.  https://www.cityofdubuque.org/804/Bee-Branch-Creek-Restoration

    Steven Brown A.M.ASCE
    Project Manager
    City of Dubuque Engineering Dept
    Dubuque IA

  • 8.  RE: Retrofit Urban Stormwater Management

    Posted 10-25-2021 01:19 PM
    Heidi,  Measure W is funded by the a 5 cent benefit per square foot assessment to impervious areas of Los Angeles County.  This money is collected and utilized by the Los Angeles County Flood Control District that provides flood control and water conservation for more than 10 million residents.  To date we have reviewed 120 projects that will intercept the storm water runoff and reuse it by either infiltration or send it to a treatment plant.  There is more than enough information that will satisfy your needs.  Good luck.

    David Sorem P.E., M.ASCE
    Mike Bubalo Const Co Inc
    Baldwin Park CA

  • 9.  RE: Retrofit Urban Stormwater Management

    Posted 10-28-2021 08:56 PM
    Check out the several urban storm water projects in the City of Champaign, Illinois.  Very impressive.

    Bill Gray

    William Gray P.E., M.ASCE
    City of Urbana
    Urbana IL