There Has Always Been a Plan B for South Boulder Creek Flood Mitigation
500-year protection is possible, but CU refused to give up enough land for it.
Prior to May 2019, City Council’s original objective was to provide mitigation for a 500-Year flood flow on South Boulder Creek. Several viable 500-Year flood flow mitigation plans were proposed. Many were less expensive, required fewer permits, and posed less environmental risk than the downsized 100-Year flood mitigation plan currently in the works.
However, none of these viable 500-Year plans left the number of acres CU wanted for development. No matter how creative the engineering, there just are not enough acres at CU South for both effective flood mitigation and CU’s development plans.
What is the Path Forward After Repeal of the Current Annexation Agreement?
CU professor and the “Father of Floodplain Management,” Gilbert White, convened an Independent Panel of Experts, to review and recommend flood management for the South Boulder Creek Floodplain. The panel presented their report to City Council at their July 17, 2001 meeting.
The main takeaways were: (1) lives and public safety must be the first priority before consideration of any other use, (2) the primary mitigation should rely on using the entire floodplain, its natural ponds, topography and streams to detain and slow floodwaters and increase adaptability, and (3) wherever possible dams, impervious floodwalls, and concrete detention ponds should be avoided.
The Report addressed three major approaches to mitigating flooding: a “Central Dam” approach, a “Manage the Floodplain” approach, and a “Local Mitigation” approach.
A Central Dam Approach to Mitigation
Repealing this agreement allows the City to consider the 500-Year central dam options, but without the constraints of CU’s land restrictions. This need not be a long process as these plans were already developed sufficiently prior to 2019, and removing CU’s acreage restrictions will simplify the process.
Once a plan that mitigates these larger floods is selected, negotiation options include a land swap, condemnation of the mitigation acres needed for public safety, or CU agreeing to restrict its development to the acreage that remains after effective flood mitigation is in place.
This approach only addresses South Boulder Creek’s main channel water, not the multiple overland flooding sources that affected the East Frasier Meadows Neighborhood in 2013. A central dam design will not offer protection against these other sources of inundation including Viele Channel and Anderson Ditch.
A Floodplain Management Approach to Mitigation
The original Flatiron Mining Reclamation Plan used ponds, topography, and riparian vegetation to attenuate the flooding they knew would be caused by mining the sand and gravel thus lowering the floodplain. This plan was accepted as a condition of the mining permit. After purchasing the land, CU used its sovereign government status to get the Reclamation Board to replace this flood mitigation plan with CU’s plan for maximum development.
Several variants of both Dr. White’s recommendations and the original reclamation plan have been proposed. These plans provide the most resilient, environmental friendly, and cost effective mitigation that could be implemented. The City never did a serious evaluation of how any of these approaches might be used.
The existing floodplain management plans need to be seriously considered in terms of implementation time, cost, future resilience, and environmental impact.
A Local Approach to Mitigation
One of the options explored by the City in 2015 was to provide local mitigation for structures and neighborhoods rather than the current model of a central dam at CU South. It is worth noting that the CU South plan it was compared to was a 500-Year plan that (1) covered more structures than the current plan, (2) was estimated to only cost $48M, (3) did not consider the regulatory, environmental, and agreement concession costs.
Local mitigation would protect the structures from all overland sources of flooding, not just South Boulder Creek floodwater. Additionally, local mitigation can begin immediately (Frasier Meadows Retirement Community has already done it for their structures), it can be implemented incrementally, and it can be expanded over time to other flood basins in the city.
What about flood safety “Right Here Right Now”?
As Gilbert White’s Independent Panel stressed, flood safety begins with actions and behaviors not engineering. The City has yet to implement a coherent, coordinated plan that begins with:
(1) Stream & storm monitoring,
(2) An improved emergency warning system,
(3) Delineation and signage of evacuation and emergency response routes,
(4) Continuous public education on these safety measures.
Nothing will mitigate 100% of the risk, and complacency and ignorance are the biggest dangers to personal safety in these situations.
Steven Telleen, Ph.D.
Boulder
I’ve been studying the flood situation again, and it is becoming increasingly clear to me that
(1) the proposed “100-year” detention pond for South Boulder Creek will not stop the areas that flooded in 2013 from being inundated again, and
(2) the related Annexation Agreement that allows massive development on CU South is full of holes and should be repealed.
Let’s be straight about the 2013 flood. Much of Southeast Boulder is a floodplain, created by South Boulder Creek, Viele Channel and other local flows. Given climate change and the resulting stronger storms, even if a storm centers on the Eldorado Springs area and drains into South Boulder Creek, it is a virtual certainty that this “100-year” pond will overtop with some frequency; so the downstream area will be flooded anyway. But if the storm centers a few miles further north over Southwest Boulder, water will come down Viele Channel, completely missing the detention pond. Then the water will do just what it did in 2013 — run uncontrolled through the U.S. 36 and Table Mesa intersection and flood much of the same area. CU has refused to let Boulder build a pond big enough to handle a “500- year” event, even though CU gets 500-year protection for all its CU South development.
Interestingly, after the 2013 flood, the Frasier Meadows retirement community, where many people were pushing the city for faster action, built berms, walls and flood gates around many parts of their property. The great advantage of such improvements is that they block water irrespective of its source. Some quick calculations suggest that far more structures might be protected using this approach for less money than by the inadequate pond.
Additionally, much of the 2013 damage was not from direct flooding, but from sewers and basement floor drain backups. The city is starting to re-line sewers. It should set up a largescale program for homeowners to lower the cost of installing backflow preventers since they have a very high level of certainty of actually preventing damage. And an early warning system would ensure that people are not surprised as in 2013. As a reminder — the only deaths in 2013 were on a road west of North Boulder, not in Southeast Boulder.
To build this inadequate pond on CU’s property, the city council signed an Annexation Agreement with CU that would allow CU’s development on the site to be almost the size of downtown Boulder. Bizarrely, this agreement could be changed by a bare majority of a future city council to increase the amount of development, eliminate the height limit, end requirements for traffic mitigation and even change the zoning to commercial to allow CU to sell the property for a windfall, all without citizen approval.
As to the traffic issue, the Annexation Agreement is, once again, full of holes. The agreement is structured so that CU cannot proceed to the next “phase” of development unless the traffic limits are maintained, but the “phases” are determined by CU. The amount CU must spend for mitigation ($5 minimum per trip) does not rise with inflation. So, by the time this mitigation is required, it is virtually certain that CU’s EcoPass program, which all students and staff get anyway, will meet the agreement’s requirement. So, expect traffic to increase without any real limit.
Finally, there is no guarantee that the city’s design for the pond will pass muster. The pond relies on unproven systems to pass groundwater through the floodwall’s impervious foundation to maintain valuable wetlands on the downstream side of U.S. 36. It also relies on a huge concrete-lined pit excavated below groundwater level to increase the pond’s capacity. This pit will also have to be maintained indefinitely, otherwise it will fill with groundwater and silt and be useless.
Of course, in the process, many of the irreplaceable natural areas in the floodplain will be gone, and we will all be the poorer. That is why almost 6,000 citizens signed a referendum giving us a chance this November to tell the council that this annexation needs to be rethought right from the beginning.
Steve Pomerance
Boulder
Steve Pomerance is a former Boulder city council member.
Despite the severity of drought in Colorado and the United Nation’s announcement of the necessity of immediate global carbon reduction, the University of Colorado-Boulder stubbornly continues to pursue its expansion into South Boulder. This is either simple-minded ego flexing or perhaps a revelation that there is an economic necessity for the project to go forward.
A retired professor told me years ago that new buildings were being financed by the income from earlier construction, a business model based on real estate acquisition that has little to do with education.
CU has become a corporate real estate tycoon with environmental goals, such as achieving carbon neutrality by 2050, that are pure green wash hog wash. It is hard to take that wiser thinking seems so absent in an institution of higher learning.
Robert Porath
Boulder
Carol Calkins’ recent CU South letter is puzzling. The letter cites “critical flood protection for thousands of our neighbors” but ignores a 2014 City of Boulder report about the 2013 flood, which showed only 30% of the damage to Frasier Meadows came from South Boulder Creek.
I believe a South Boulder Creek dam is one of the biggest drivers for CU South. Yet it’s the wrong dam, on the wrong tributary, in the wrong place. To “protect our neighbors,” the city should mitigate what caused 70% of their damage.
Further, developing a campus in a floodplain will require thousands of tons of fill dirt to elevate the site — at the expense of Boulder households. City residents and businesses will have to significantly fund CU South’s expected $46 million cost through increases in our water bills.
The letter claims traffic concerns are “clearly addressed.” I believe counting car trips during 2020’s COVID lockdown produced a skewed undercount. Additionally, since that traffic study, CU enlarged CU South by 50%, from 500,000 to 750,000 square feet of non-residential space. There’s no traffic study on the 50% larger size.
The letter is also incorrect about CU South’s onsite housing. Based on standard commercial real estate figures of 150 square feet per person, 750,000 square feet of space could draw 5,000 more students, faculty and staff. CU is only housing 2,200 people at CU South, which could add 2,800 more un-housed people to Boulder’s already overstressed housing market.
Vote yes to repeal CU South in November!
Emily Reynolds
Boulder
August 2021
On August 3 the Boulder City Council held the first reading on the proposed annexation agreement for the CU-South property. This agreement is being pushed through at a rapid pace ostensibly for flood mitigation. I hope the Council will consider a few facts from the 2013 flood-loss impact summary, compiled in 2014 by the City of Boulder on the basis of FEMA’s assessment of damages, because it directly affects all Boulder residents, not just those in the South Boulder Creek Drainage Area.
To summarize:
- Focusing on the SBC drainageway does not address other drainage areas in the city that suffered more damage. The focus and priority should be on the areas that suffered the most damage first. If this proposal is approved will there be money left to address the areas that suffered more damage than this one?
- The 2013 flood was considered a “70-year flood” and yet 44% of the damage occurred in the 500-year flood zone. This should raise concern about the current 100-year solution adopted by City Council for the SBC drainageway!
- In the SBC floodplain, 70-80%% of the damage was caused by non-stream related water that the current CU-South proposal does not address or mitigate.
- Of the stream-originated water, 65-70% of the water came from local-drainage flooding rather than SBC. This suggests that focusing on mitigating the local-drainage issues first might provide more effective mitigation than the current CU-South proposal.
If the above is not enough to concern you, consider that every Boulder resident will pay for this directly or indirectly, because the proposed financing is via a utility fee increase not a tax increase. A tax increase would trigger an automatic TABOR vote.
The bottom line is: the data do not support making the highest priority the annexation of CU-South for mitigation of South Boulder Creek (SBC) flooding. This is particularly true when the many tens of millions of dollars this agreement requires will take money away from other areas in the city that suffered even more damage during the 2013 flood.
According to the City’s own document, the ranking of losses by drainage basin places SBC in 3rd place ($27,815,855) for the Total Estimated Loss behind Boulder Creek ($41,276,084) and Two-Mile Canyon/Goose Creek ($39,101,067).
However, these totals are misleading as the data document that much of the SBC flood loss in 2013 came not from SBC, but from local drainage flooding and other non-stream related issues (sewer, groundwater, etc.). Since the CU-South annexation proposal would only address flooding issues for SBC, it is worth ranking the drainage basins using the loss data from the “Major drainageway flooding” category. In this ranking SBC drops to fifth place behind Boulder Creek, Two-Mile Canyon/Goose Creek, Wonderland Creek, and Gregory Canyon.
This City-compiled document also provides data comparing SBC losses in the 100-year versus 500-year floodplain.
Almost half (44%) of the damage done in the SBC Floodplain was in the 500-year flood zone area outside the 100-year flood zone ($15,841,479 for the entire 500-year floodplain minus $8,957,975 for the 100-year portion equals $6,983,522 outside the 100-year floodplain).
This alone should indicate that a 100-year solution may be inadequate even for a 2013 level storm. Approving this agreement, which only addresses a 100-year level storm, would lock-in a solution that is likely inadequate and certainly not resilient.
The document also shows that only 30% of the overall damage in the SBC 100-year floodplain was from stream flooding (SBC plus local streams), and 65% of that stream-flood damage was from local stream flooding, not the Major SBC drainageway.
Applying these same calculations to the SBC 500-year floodplain only 21% of the total damage was from stream flooding, and 70% of that stream-flood damage was from local stream flooding not the Major SBC drainageway.
This suggests that even if the proposed SBC mitigation plan does successfully contain the Major SBC drainageway water, which essentially is the entire rationale for quickly approving a CU-South annexation agreement, it will only account for 35% of the 30% of the total damage (about 10% overall) in the 100-year flood area and 30% of the 21% of the damage (about 7% overall) in the 500-year area.
Analysis of these data strongly suggest that the current CU-South solution in any configuration is not likely to provide Boulder residents with the mitigation promised by the City, yet the Council continues to rush to sign an agreement based on an artificial deadline.
Tell the City Council, you want an effective solution, not a rushed agreement
Steven Telleen
Boulde
I’m part of a group of citizens helping Boulder city staff on the master plan for stormwater and flood protection work for Boulder’s waterways, other than South Boulder Creek.
Just last week, we had some interesting discussions about whether we should focus more on how to prioritize the many projects that would cost in total hundreds of millions of dollars, or focus more on increasing the near-term funding for these projects to reduce the need to prioritize by doing more projects concurrently rather than sequentially.
To give this some scale, current funding is approximately $7 million annually. City staff predicts that it may take more than 50 years to complete the work, and that upping funding to $11 million per year would allow completion in around 30 to 35 years. The total cost is estimated at roughly $350 million for about 30 projects.
Per the 2014 Flood Impact Survey of those drainages impacted by the 2013 flood, damage was over $176 million in 2014 dollars, about $215 million now.
Flood insurance paid for about 14% of estimated damage, and about 28% of actual claims. Sewer backups and groundwater infiltration caused extensive basement damage not covered by flood insurance, and localized street flooding outside the “100-year” floodplain meant many affected property owners didn’t have flood insurance. Unaccounted damages included cost of being displaced from peoples’ homes and loss in market value.
What pushes me toward moving as quickly as possible is simple logic: The sooner the flood work is done, the less likely it is that a flood will occur before those improvements are made. If not done, flood damage plus potentially more costly flood improvements could close to double the total cost.
For me, this swings the debate toward getting the job done as quickly as reasonably possible. Also, flood insurance is likely to become more and more expensive and less and less available, because climate change is radically increasing both the magnitude and frequency of floods, affecting both FEMA and private insurers.
Trying to prioritize projects is hard. It sounds easy — just do standard cost/benefit analyses. But frequently, both the locations and the values are hard to compare. For some locational examples, where I live, we have King Gulch on one side, which is relatively easy to flood-proof because it’s small, and existing channels handle much of the problem, though it still flooded many houses because some stretches don’t have adequate channels or pipes.
On the other side is Bluebell Creek, which is very difficult to deal with, since it runs mostly in small channels through people’s yards. Other areas have much more complex design issues.
On the “values” side, for example, there are issues around social equity, because just analyzing damage costs puts more emphasis on well-to-do neighborhoods, whereas, for example, using dwelling unit numbers tends to focus more on less welloff areas.
And then there are critical facilities, historic sites, cultural resources and environmental issues to consider and protect. Just sticking numbers on each of these may make the evaluation math look easy, but it avoids facing the incommensurate nature of the underlying values.
Accelerating the process of building the infrastructure doesn’t necessarily require big increases in utility rates. The same work gets done; it’s just a matter of how fast. As an “enterprise fund,” the utility can borrow relatively cheaply and interest rates are still pretty low.
Additional staffing for such a 10- to 20-year project could be experienced engineers looking for an interesting project to fill the time before or during retirement.
The basic sequencing of projects might be:
Life/safety: early warning system with full coverage, street analysis regarding closures, escape routes, etc., with informational brochures supplied to residents.
Sewer pipes and stormwater systems: projects to line, clear, rebuild, etc. These are already scheduled and funds are available.
Flood control: organize the projects, ensuring that they both provide adequate and cost-effective protection (not like the University of Colorado Boulder South Campus, which is neither), while meeting other relevant values.
Bottom line: I don’t think anyone wants to be in the position of dealing with another 2013-size flood, which could happen in any year, and have to say, “We could have prevented the damage to your residence or business on Drainage X, but we didn’t because we didn’t want to raise the fees or borrow the money. But now we need to fix the damage and do the flood improvements, which may be more expensive and extensive.”
So, everything else being equal, faster is better.
Steve Pomerance
Boulder
Steve Pomerance is a former member of the Boulder City Council.
When it comes to CU South, Carol Calkins (letter to the editor 7/14/22) has her facts wrong and seems to be pushing CU’s expansionist greenwashing.
Fact: Experts like Gilbert White have recommended 500-year or more flood mitigation for CU South. The current 100-year flood mitigation proposal is based on a specific design storm that occurs over Eldorado Canyon - very different from what occurred in 2013. Only XXX homes would be protected if the proposed system works perfectly as designed.
Fact: CU owns the land, but it is adjacent to a critical and high-value part of the South Boulder Creek wetlands that was purchased by Open Space, and which may now be under threat of dewatering from the flood mitigation dam.
A large portion of the area purchased by CU was designated as Open Space in the Boulder Valley Comprehensive Plan for many years. In usual annexations, the designated land uses in the comprehensive plan are followed in determining the requirements.
Fact: CU’s flawed traffic study estimates an additional 6,316 trips per day as a result of CU South. There will be also be a dangerous new intersection on Highway 93 near Marshall Road. The proposed “trip caps” are completely unenforceable in a real-world setting.
Fact: The 1,100 new units at CU South will be a mixture of market rate housing, graduate student and undergraduate student housing.
Most annexations in Boulder would be required to include 40% affordable housing, but at CU South, just 5 acres have been designated for affordable housing.
CU South also includes 750,000 square feet of non-residential buildings which translates into between 3,000 and 5,000 additional people needing housing depending on whether it is classroom, office, or research space. More jobs than housing is not a solution for Boulder, it’s more of the same old problem.
Fact: Flood plains are designated by the federal government, but mother nature decides what happens in a flood. Historic photos of the South Boulder Creek floodplain show the extent of historic flooding at CU South far beyond current FEMA designations. Climate change mean more intense flooding and 2013 showed us that floods in Boulder can be very different than expected.
The CU South Annexation agreement is a one-sided deal that favors CU. The arrangement asks Boulder citizens to pay for major expenses and CU gets cheap water and sewer hookups for their 2,500,000 square feet of development. Growth should pay its own way.
Repeal the bad deal. Vote Yes.
Peter Mayer
Boulder
With the Limelight Hotel under construction and with plans for a convention center kitty-corner at Broadway and University on the Hill and a new "South Campus" expansion equal in size to a good chunk of its existing campus, CU clearly displays a burgeoning ambition that has more to do with business and profit than with the education of students.
Thus far the "movers and shakers" of the city are thilled with these plans, the impact of which on the quality of life of Boulder citizens, congestion, traffic, and pollution, have been of little concern.
Boulder once had a certain aura of being quirky, outside the mainstream, somewhat exotic in Middle America all because of the presence of the University. "The People's Republic of Boulder" and "Baghdad by the Flatirons" were appellations given at different times.
The Board of Regents, elected statewide and until the last election, Republican dominated, chafed at all the "liberal" tendency but was unable to turn the tide until the selection of Bruce Benson, successful oil man and GOP fundraiser, as President depsite his having no expertise in education and only a Bachelor's Degree in Geology. His selling point was fundraising, and diminishing state funding had left the university in financial straits.
Conservatives had been calling for universities to be run as businesses for decades. Under Benson's tenure, the bottom line became the focus of all operations, including sports. The business plan was simple: money had to be made and he was successful at putting CU on firmer financial ground with a current operating budget of $2.1 billion for the Boulder campus alone ($5.5 billion systemwide).
Administrative costs continue to rise, but its expansion ambitions remain flush with cash. Nonetheless, tuition and fees for students continue to climb and gender inequality in faculty salaries, while recently lessened, remains the norm.
All in all, be it questions of education, the well being of students, faculty, and the people of Boulder, or the reality of climate change, persisting drought, and the necessity of carbon reduction, CU's answer has been Lily Tomlin's classic line, "We don't care. We don't have to."
It shows arrogance and should shock everyone.
Robert Porath
Boulder
Help us get out the vote in November and get 500-Year Flood Protection. Repeal the CU South Annexation and Stop Ignoring Climate Change.
Paid for with major funding from PLAN-Boulder County, Save South Boulder & Alan Boles