Floodplain Homework For Denver City Council
Take These Six Steps To Help Reduce Flood Risk In Park Hill
By Brian Hyde
For more than 150 years since the Colorado Gold Rush of 1858, land development and infrastructure activity has occurred within the Montclair Creek and Park Hill Creek watersheds. For all but the last two years of that time, there was no detailed floodplain mapping – the most common way in which we understand our risk from floods – to guide or inform how our neighborhoods take shape. Only in 2014 did such floodplain mapping become available.
Wagon roads, railroad tracks, streets and highways were laid out without that mapping. Individual lots and subdivisions were platted. The infrastructure was constructed. Shops, industrial facilities and houses were built. The city’s crown jewel park, City Park, was designed and landscaped without floodplain mapping.
Two years ago, the right combination of people, computer technology, and data resulted in the technical capability needed to map the complicated flow patterns of floodwater. The mapping captures the patterns through multiple street intersections, roads and tracks functioning as dams (or as canals), and even buildings that were part of the stream channels.
Without a time machine, we cannot simply wave a magic wand and rearrange the buildings and the infrastructure. We cannot superimpose bridges and segments of open channel. We cannot create open space corridors to ensure that flood flows avoid homes, businesses, or streets. We cannot move homes that our friends and neighbors live in or raise buildings several feet higher to get their basements above floodwaters.
All of that kind of work has to be done one tough step at a time, without supernatural powers. It is a daunting task for the professional experts. It is a daunting task for us, the residents. What makes each step tough is not just the technical difficulty of the work. We have political considerations, economic/budgetary constraints, and human nature to contend with. We have our personal and our collective values systems that we bring to the table.
The work will be difficult. The sooner we decide to roll our sleeves up and have those difficult conversations together, the better. The sooner we collectively chart a course that reduces our risk, honors our values and moves us forward (as opposed to sideways or backward), the better.
Here are six things Denver City Councilmembers and their staff can do almost immediately, as first steps toward reducing flood risk in Park Hill:
1. With help from the Urban Drainage & Flood Control District (UDFCD), they should prepare floodplain information reports. These reports should not include proposals to alter the existing flood elevations or the existing floodplain boundaries – just delineations of existing flood hazards – for Montclair Creek and for Park Hill Creek.
2. They should formally adopt those reports.
3. They should publicize the existence of and the contents of those reports.
4. They should intensively engage with neighborhoods and help us all to better understand how we, personally, can reduce risk from flooding. Help us to help the City implement solutions that enable the neighborhoods, and Denver, to thrive.
5. They should then implement a program that temporarily mandates obtaining a floodplain development permit prior to any construction or alteration of current conditions within the 1 percent annual risk (100-year) floodplains shown in those reports. Prohibit basements within those areas. Once a master plan has been developed for a sub-basin, city council can require compliance with that master plan instead of the temporary mandate.
6. Finally, council should implement a program that installs, within one year, informational signs that warn all drivers of the risk to parked cars from flash flooding in all public parking locations within those two watersheds subject to 100-year flood depths greater than six inches.
I believe those six points provide all of us with some useful and challenging homework.
Brian Hyde is an expert in floodplain management and stream restoration. He wants your feedback at westerly_connect_brian@comcast.net or 720-939-6039