By Daniel Johnson
There has been extensive discussion about the South Boulder Creek Flood Control project over the last decade or more. Many options have been forwarded, studied and ranked. The current concept is the preferred and most efficient alternative. The negative interference by opposing parties needs to stop and the referendum to repeal the annexation of CU South into the City on this November’s ballot needs to fail.
I am a civil engineer with nearly 50 years of worldwide water resources experience in water storage, retention and release. I was a member of the Water Resources Advisory Board from 2012 to 2017 when in 2015 the WRAB, city staff and the City Council evaluated many options and selected Option D to proceed. Option D is very similar to the design of the selected option. This option made sense back then and makes sense now.
In recent years, the project has been improved and now includes many overall site enhancements, including those within the terms in the Annexation Agreement. The city gains multiple benefits from the project — in addition to flood protection, open space development and public access, it provides significant controls on the university’s development plans. These benefits will not exist if the referendum is passed.
One of the opposition’s delay tactics has been to advocate for increasing the size of the floodwall (and cost) to contain the 500-year flood instead of the 100-year flood. This is not possible and really does not significantly increase the benefits of the 100-year flood project:
- The discharge from the 500-year detention facility could exceed the design capacity of the U.S. 36 channel underpass. CDOT will not allow the larger flow.
- Should this flow be discharged through the U.S. 36 channel, downstream landowner flooding could increase beyond that resulting from the 100-year option, which FEMA will not permit (“no adverse impacts downstream”).
- Environmental impact is greatly increased due to the larger size and its operation.
- Project costs are significantly higher which could cause lengthy delays or possible elimination of other Boulder flood control projects and decrease city-wide flood safety. There are 15 other flood pathways through Boulder that need flood control as defined in the city’s Flood and Stormwater Master Plan.
- Permitting will be significantly more complex, expensive and delayed due to the increased project size and water management impacts. This is the “least environmentally damaging option.”
So, the only path forward is to continue with the design and construction of the flood control project for the 100-year recurrence level flood. At this level of protection, the safety of the downstream population Is greatly enhanced.
The 100-year option greatly reduces the inundation (flooded) area — many fewer homes will be impacted. The 500-year option provides a bit more reduction in this inundation footprint, but it is not proportional to the benefits of the 100-year option over the existing condition.
For floods larger than 100-year, the flood wave will be delayed in the Thunderbird and Frasier Meadows areas by storing the first 152 million gallons of water. There will be many hours between alerts and the arrival of flood waters not contained by the 100-year flood protection structure. This will enable early flood warnings and an orderly evacuation of people and pets, and it will allow time to try to protect property. As stated in the project risk assessment completed by HDR, “Maximizing the warning time of an impending flood given to citizens may be the most effective way to save lives and protect the public.”
It is well past time to complete this project. All the components are in place, the design is being finalized and the projected benefits are greater than imagined when the project was developed. The referendum will just indefinitely delay implementation and increase the costs of this vitally needed project. If this project existed for the Sept. 2013 flood, the South Boulder Creek downstream neighborhoods would have had minimal impacts. There is no need to delay longer — the next flood is approaching, and Boulder’s citizens deserve to be safe. As a longtime resident of Boulder, I am voting no on the referendum.
Daniel Johnson is a civil engineer. Johnson lives in Boulder.
