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Flooding caused by Denver Development

Updated: Jun 12, 2023

Denver development has gotten out of control in the past 10 years. Entire neighborhoods are having historic, small, affordable homes demolished in place of giant homes, garages, or multi-unit dwellings that cover every inch of the permeable land possible and allowed.

Denver Yimby: Flooding caused by Denver Development

Denver's immense amount of recent urban development affects flooding in many ways. As our small homes are replaced with larger buildings and ADUs are added into backyards, each lot is removing vegetation and soil, grading the land surface, resulting in substantially increasing runoff from the property. This extra runoff can cause more flooding of our neighborhoods during heavy rain storms. Urban flooding happens when water flows into an urban region faster than it can be absorbed into the soil or moved to and stored in a lake or reservoir.

Due to the unprecedented amount of new townhomes, ADUs and skyrises being built in our Denver neighborhoods, flooding has increased dramatically in the recent years – because when a developer purchases a single-home lot and then demolishes the house to build a much bigger building, much of the permeable land is lost – and the water can no longer be absorbed.

In new developments that are sadly sprawling across our entire state, typically flood control and big open spaces are part of the overall plan (not because the developers want to put them in, but because they have to in order to help control flooding when they pave over permeable ground to build neighborhoods). Take the Stapleton (now named Central Park) neighborhood for example, which built in drainage ways in the form of naturalized parks to accommodate all the extra pavement and homes that would be built over the existing permeable ground.

In our historic Denver neighborhoods, there is no "open space" left to catch excess stormwater – the open space and permeable land is woven everywhere in our neighborhood in the form of our large landscapes in our front yards and back yards. When developers build an ADUs or a multi-unit buildings on a lot that was formerly a small home with a large landscape, the potential for flooding for the area increases because a ton of permeable ground is lost. When it downpours, the water has nowhere to go but to the city storm drains, which then get backed up and flood homes along these historic waterways shown above. The more we build over backyards and fill entire lots with buildings, the more flooding will increase during storms. Denver residents in our neighborhoods should not be subjected to this lack of planning or foresight by the city planners and developers. Permeable ground should not be allowed to be covered up in established urban neighborhoods – as this will increase flooding due to backed up storm drains that were not designed to carry the additional load of runoff water. The city is trying (unsuccessfully) to improve the storm drainage, but we have limited land to work with to store stormwater, and building bigger stormwater drains is an ongoing expensive and never-ending process (such as the 17th and Colorado stormwater project, for example). As we keep building ADUs, housing and other building over our permeable ground, even the larger sewer drains just can't keep up during heavy rainfalls.

This map above shows the drainage "hidden rivers" that we have developed over. Here's some pictures from 14th and Krameria, an area that often floods during heavy rains such as the storm on Sunday, August 8, 2022. Sadly, this entire neighborhood area is zoned for more building and we are seeing small homes with large water-absorbing landscapes being purchased by developers, razed, and replaced with multi-unit housing that covers nearly the entire lots. This flooding will continue to get worse, as our storm water drains simply can't handle the added amount of water:

Water-absorbing and pollution-reducing trees and landscapes should not be allowed to be removed to build larger buildings or impermeable hardscapes.

Denver Yimby: Flooding caused by Denver Development in East Area Plan

Take, for example, the property shown above. A developer recently purchased this historic small affordable home shown on left at 1327 N. Jersey Street. They are going to demolish this affordable, charming small home and replace it with a 10-unit building – right next to single-family residences. I highly doubt that any of the 10 units will be more affordable than the home was for the amount of space. And, this 10-unit structure will likely take up every inch of land allowed, leaving the neighbors with a new heat-island and more flooding potential. Additionally, I suspect the 10-unit building will be much higher than the beautiful home that it will replace, thereby shading the neighbors to the North – in effect, stealing their sun, causing ice issues and higher energy bills in the winter months.

To top it off, see the sign below from our Mayfair neighborhood, where Pete Pappas has requested to build less parking not to save permeable space, but so they can squeeze more units and make more money at the cost to the neighborhood. Developers will always tout that the new residents won't need cars, but that's a fallacy – of course they will need cars! Our public transportation system is unaffordable, infrequent, and inconvenient, and there are no good options to get to the mountains, which is where nearly every one of the new residents will want to go. The neighbors will be the ones who suffer when parking on their street suddenly becomes congested with cars lining the entire street and blocking their driveways. And, to make things worse, these narrow streets were not made to handle parking on both sides, so it makes it difficult for two cars to drive down the street in opposite directions without having to pull over to let the other car come through. Congestion, noise, pollution. The developers claim they are creating more housing to help our neighborhoods, when, in reality, they are turning our neighborhoods into congested, overcrowded, noisy, hot places in exchange for MONEY. They are basically pillaging our neighborhoods and walking away with millions.

Denver Yimby: Flooding caused by Denver Development in East Area Plan - Builders are not building enough parking!

Every landscape that is covered with buildings or concrete becomes part of the problem.

Denver City Planners, we ask you:

Where does all the water go now that the city has allowed developers to build over every inch of permeable surface possible?

Denver YIMBY: Flooding caused by Denver Development

Above is an example of the problems of density and water runoff – shown here is an example of a snowplowing company moving all the snow from the completely paved over property of a series of rowhomes into a neighboring yard (without permission.) Because they paved over every inch of this property, there isn't anywhere for the snow to be plowed, the snowplowing company should have found a place to put it on the property or removed it fro the property to relocate somewhere where it is legal to do so, rather than dumping it into neighboring property without permission. Denver City Council has recently changed zoning recommendations for the East Area of Colfax to allow for more density already. They also keep pushing more changes through, using the past few years of the Covid-19 pandemic to pass through unwanted zoning changes to our neighborhoods, even though there has been widespread public outcry from thousands of the property-paying residents who live here. See what has happened over on the West side of Denver – landscapes are quickly disappearing under row homes and density housing:

We have to stop Denver city planners and city council from from changing our zoning, and protest the destruction of our historic landscapes and homes to be replaced with high density overpriced housing. We are Denver YIMBYs for good – and we're all about protecting what's left of Denver's open spaces and small, affordable historic homes! Let's not let developers come in and build multi-unit high rises and dwellings in our neighborhoods, causing flooding, congestion and problems for everyone.



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