Where the Water Is Likely To Flow

Last month, I asked you to take a trip with me to an imaginary new “Montclair Creek Town Centre” just southwest of Monaco and Colfax.

I referred to some mapping of “Potential Inundation Areas” (AKA “floodprone areas” or “floodplains”), recently made publicly available by Denver Wastewater. So, at the risk of exposing you to more of the left side of brain, let’s explore that mapping.

This month’s column includes two maps. They are part of Denver’s 2014 Storm Drainage Master Plan. The first map displays the 1 percent (100-year) risk of flooding at the Town Centre’s site. The technical information in this first map guided my “creek and pond bubble” concept for the proposal.

Remember that the Montclair Drainage Basin is the largest storm drainage basin in Denver that does not have a surface drainageway.

I have spent plenty of time in flooded communities throughout Colorado (and elsewhere, including Waveland, Miss. right after Hurricane Katrina) in my 35-plus years as a floodplain manager. I know viscerally what a community looks and feels like when it has just experienced the loss of some of its citizens and the loss of some of its treasures – whether natural or constructed by humans. On a few occasions, I met people who believed that Mother Nature had tried to take their community’s soul.

While there are places along Montclair Creek that could see more than 6 feet of water in the event of a major flood, by and large a 1 percent flood would primarily endanger buildings and any cars driving through low places. However, we can suffer awful consequences when we presume too much about floods.

Every time I drive north of I-70 on Colorado Boulevard and turn onto Vasquez Boulevard on my way to I-270, I have a flood tragedy flashback. As I cross the train tracks near US Bank, I am reminded of a brave police officer who lost his life there, many years ago, rescuing a drowning woman.

Bet you didn’t know that there was a creek or a floodplain there! And, ironically, most of the upstream watershed of that creek is in Park Hill.

At the end of the locker room meeting of the TV cops on Hill Street Blues, and Sergeant Phil Esterhaus reminds all of us, “Let’s be careful out there!”  With that admonition in mind, the map below should illustrate how the intersection of 14th Avenue and Kearney can literally swallow cars during an intense rain.

Friends and neighbors, please be careful there.

Being both a planner and an engineer, I feel compelled to place the map above in a larger geographic context. The Montclair Creek watershed extends from Fairmont Cemetery to City Park and on to Riverside Cemetery along the South Platte River.

Another map is the best way I can convey that bigger context. Again, I am taking advantage of engineering information made available by Denver Public Works. The map below shows both branches of Montclair Creek, with the colors representing the depth of flooding during a 1 percent flood event.

The area on the map extends from 6th Avenue to 17th Avenue, east-west from Quebec Street approximately to Steele Street. Our Town Centre site is a little east of the middle of the map, southwest of the intersection of Monaco and Colfax.

I think you’ll agree that our site is not the only place that jumps out visually, but it is certainly one of the most prominent of those places. It jumps out both in terms of the colors that represent flood depth and in terms of the width of the area subject to 1 percent flood risk. Check out some of the other places as well.

Because there is a lot going on right now in the watersheds of Greater Park Hill, next month I want to look at the bigger picture, checking in on activity in the Montclair Creek Watershed, the Park Hill Basin, and the Westerly Creek watershed.

The maps now available from Denver Public Works make it far easier for me to show you where the water is likely to flow the next time it rains really hard.

And those are precisely the places I would love to see turn into “Blueways” – part of a neighborhood that is ready for a big dose of green infrastructure.

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.