South Boulder Creek Flood Mitigation/CU South

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The South Boulder Creek Flood Mitigation Project is a 17-year effort to study and take community/and advisory board feedback about how best to protect residences and parts of town that are at risk for catastrophic flooding from the South Boulder Creek drainage-way.


In February 2020, City Council indicated a preference for a 100-year flood protection because it has the least environmental impacts, the lowest cost and the greatest probability of meeting the project design criteria. Prior to making a formal flood design level recommendation on June 16, 2020, City Council has requested that staff update the public on the project status and seek input on the remaining items at this stage in the conceptual flood design. Specific topics of interest, including upstream detention viability and and open space and environmental mitigation, will be areas of focus at the June 3, 2020 Open Space Board of Trustees (OSBT) meeting.


The purpose of this Be Heard Boulder Project page is to give the Boulder community an opportunity to ask questions and share thoughts related to flood project tradeoffs, design or flood design information previously provided to council.


The following is a graphic that shows engagement related to the flood design between now and mid-June 2020.


The South Boulder Creek Flood Mitigation Project is a 17-year effort to study and take community/and advisory board feedback about how best to protect residences and parts of town that are at risk for catastrophic flooding from the South Boulder Creek drainage-way.


In February 2020, City Council indicated a preference for a 100-year flood protection because it has the least environmental impacts, the lowest cost and the greatest probability of meeting the project design criteria. Prior to making a formal flood design level recommendation on June 16, 2020, City Council has requested that staff update the public on the project status and seek input on the remaining items at this stage in the conceptual flood design. Specific topics of interest, including upstream detention viability and and open space and environmental mitigation, will be areas of focus at the June 3, 2020 Open Space Board of Trustees (OSBT) meeting.


The purpose of this Be Heard Boulder Project page is to give the Boulder community an opportunity to ask questions and share thoughts related to flood project tradeoffs, design or flood design information previously provided to council.


The following is a graphic that shows engagement related to the flood design between now and mid-June 2020.


CLOSED: The time for submitting questions has lapsed. City staff members are still answering questions received prior to May 13 and all questions and answers will remain here for community members to read. Thanks to all who participated!

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    How will the design and construction provide for enhanced wildlife passage under US36 beyond current concepts indicated in the preliminary design and construction? Many species migrate along streams for food and reproduction. How will hikers, runners, birdwatchers, and bicyclists navigate thru the site and past highway 36? How do you value the worth of the interconnected web of species living in the wet meadows? When I was on the city's wetlands advisory board years ago, scientific researchers agreed that it was impossible to recreate a wetland with the interdependencies of the the various species, soil types, plants, and microbes. Did you include in your models the following values of wetlands and native ecosystems: resiliency, the ability of plant communities to absorb and hold floodwaters and gradually release it; the ability of native plant communities to hold soil and prevent erosion and the degradation of water quality for wildlife and downstream users ; and the prevention of diseases spread by vectors such as fleas, mosquitos, bats, and wild birds. David Quammen in his book Spillover, mentions that biodiversity and larger areas biodiversity are keys to preventing spillovers of diseases that often occur when an ecosystem is simplified, disturbed, or merged with development.

    3ouzel asked about 2 months ago

    The proposed flood mitigation project has been found to have the least environmental impacts of the alternatives considered, including those to wetlandsProject design criteria includes replication of existing groundwater flow patterns to prevent upstream groundwater mounding, drying up downstream wetlands and/or other potential adverse impacts. The design has not been determined to effect wildlife passage under US36, although enhanced wildlife passage under US36 could be considered as possible environmental mitigation during the preliminary design phase of the project. No project impacts are anticipated to the existing South Boulder Creek trail and the US36 regional bike trail will be maintained in approximately its existing alignment. Environmental considerations associated with the existing levee, including its relationship to the floodplain, will be discussed at the June 3 Open Space Board of Trustees meeting  

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    How much floodwater will be detained with each of the 100, 200, and 500 year options? How much water could be detained in the gravel pit?

    Harlin asked about 2 months ago

    The table below provides the design detention volumes for each option: 

    Project Configuration 

    Detention Volume 

    (acre feet) 

    Option 1 (100-yr) 

    467 

    Option 2 (500-yr) 

    768 

    Option 3 (200-yr) 

    659 

     

    It is important to note that flood mitigation results from both detention and conveyance. The detention volume is one component of the design along with the conveyance capacity of the outlet worksThe current configuration of the CU South property does not provide substantial storage without additional modification (i.e., construction of a berm/embankment) to detain water. 

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    Why does the “cooperation” between the city and CU on flood mitigation plans involving CU South property appear to be extremely unbalanced in favor of CU, including plans to move forward with annexation of property and taking on financial responsibility for work on the land to make it easier and less expensive for CU to develop--for CU’s benefit--without any transparency on CU’s part regarding their development plans? Why is the city not demanding that CU provide details about their plans for development before the city agrees to annexation?

    Brookie asked about 2 months ago

    Protecting City of Boulder and Boulder County residents from future flooding events is a primary driver of activity in this area. The city Utilities Department does not own the land or have utility easements for the proposed flood project. A portion of the land needed for flood mitigation is owned by the university. The land needed for flood mitigation is only available if and when the entire CU South property is annexed. There are currently no options to proceed with the flood mitigation dam without annexing CU SouthUnfortunately, the timing of the city’s flood mitigation project and planning for future development on this site do not align. In light of the desire to move forward with flood control (accompanied by annexation) even in the absence of development plans from CU Boulder, the city and county adopted the CU South Guiding Principles in 2017 as part of an update to the Boulder Valley Comprehensive Plan. The guiding principles include concepts for controlling development like building height limits, an emphasis on residential uses, public access to trails and ways to address off-site transportation impacts (e.g., the number of trips per day, transit service). Further refinement of annexation details are in part dependent upon a flood design. Therefore, more in depth annexation negotiations and community engagement opportunities are anticipated after a flood design is chosen in June 2020.  

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    These are follow up questions to the questions asked by Boulder Citizen, asked 8 days ago: Thank you for your response. I have some follow-up questions. 1. In terms of your answer to my previous question, Is any tax payer money going to CU for this flood mitigation project? Follow up #1: Am I correct in saying yes, Boulder citizens are paying CU Boulder 15 million to put the damn on their property. (Table 3, opinion on probable impact costs). Follow up #2: Why does the city say that CU Boulder is giving us the land if we are actually paying them 15 million? 2. Where is there consideration of the impact to surrounding neighborhoods (not only downstream)? I do not see an answer to this question in your response. Could you please highlight your response to this question? 3. In terms of your answer to this question: What alternatives exist for proceeding with the damn work without annexing the CU property? You say: There are no alternatives. Follow up #1: Where does it say in the Boulder Valley Comprehensive Plan guiding principles that there are no options to proceed with the flood mitigation dam without annexing CU South? Can you please provide a page and paragraph number or give the exact wording in the plan that says this? Follow up #2: Why does the city say that CU Boulder is giving us the land if the city is being forced to annex the land against the will of Boulder citizens?

    Boulder Citizen asked about 2 months ago
    1. No taxpayer money is going to CU for the flood mitigation project. The project will be paid for by Stormwater and Flood Management Utility rate payers  

    Follow-up #1. No. Project costs are paid for through utility bills, not through taxes 

    Follow-up #2: The $15 million is an estimate of existing structures or features that will be impacted by the flood mitigation project and is unrelated to the 80 acres of land the university has committed to convey to the city for construction of a flood mitigation project or to be used for open space mitigation related to the project. If CU did not convey the 80 acres, the city would have to purchase that as an additional project cost. 

    1. The flood mitigation project will address flooding in the West Valley overflow and will not address flooding in surrounding neighborhoods. Impacts of CU South annexation to surrounding neighborhoods will be considered as part of the annexation process. Annexation agreement negotiations will be guided by the CU South Guiding Principles and will provide opportunities to influence the annexation terms through city boards and the City Council meetings. The schedule and process for these meetings will be further refined once a South Boulder Creek flood mitigation design level is chosen, which is anticipated in June 2020.  

    Additionally, a multi-modal transportation and access study will be completed prior to annexation to determine necessary improvements, appropriate points of access, performance standards (e.g., trip budget) and other related topics. City staff will coordinate with CDOT during and after the study and each impacted neighborhood will be consulted throughout that process. The study can be completed once a flood mitigation concept is chosen and more is known about the related impacts to the site. 

    1. Follow-up #1: The city Utilities Department does not own the land or have utility easements for the proposed flood project. The university owns a portion of the property. Page 3, paragraph 1.b. of the Boulder Valley Comprehensive Plan CU South Guiding Principles states Specific real property ownership, easements, and/or agreements will be established during annexation for the area necessary for floodwater improvements and other uses...” The related figures depict the 129 acres of developable land required by the university in any acceptable flood alternative.  

     

    Follow-up #2: Boulder City Council representatives will ultimately vote on whether to accept the negotiated annexation agreement on behalf of the City of Boulder. 

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    In 2001, Gilbert White, Boulder’s most eminent flood management expert, chaired an independent commission that reviewed the CU South property and Prof. White concluded that the site was not appropriate for the level of development CU has proposed because it is in the flood plain of South Boulder Creek. Why has the City abandoned the guidance of Gilbert White? What has changed since he conducted his analysis?

    PLAN Boulder County asked about 2 months ago

    Work subsequent to 2001 has informed the current project approach. Specifically, floodplain mapping accepted by FEMA in 2010 describes the West Valley flood risk discussed in the South Boulder Creek Major Drainageway Plan that was accepted by council in 2015. In 2017 the city and county incorporated these floodplain considerations in the Boulder Valley Comprehensive Plan CU South Guiding Principles that allow for flood mitigation on and guide the development of the CU South property.  

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    What is different about the 500-year design that makes CDOT unwilling to accept it?

    PLAN Boulder County asked about 2 months ago

    The flood mitigation project’s design criteria require no adverse impacts to downstream property owners, including the US highway 36 bridge. This means a successful design must match existing hydraulic conditions through the bridgeThe 500-yr event flows and depths increase through the US36 bridge and therefore do not meet these criteria.   

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    Hello, I have 6 questions, below. I hope it's ok that I'm submitting them in a group. I appreciate your help. Frances 1. Historic flows were used for the designs. Why wasn’t the increased flood intensity and amount, which is expected due to climate change, factored into the designs and into the discussion? 2. Will you please provide a map of the City showing the amount of development/structures in each drainage and the levels of flood protection in each of those drainages? If possible, would you also give a rough estimate of the cost and possibilities for creating flood mitigation structures/measures in each drainage? 3. The Variant 1 designs require a dam to be placed between the Highway 36 embankment and the floodwall that runs parallel to it. CDOT has advised that no above-ground structures can be placed in its right-of-way. (a) Why is the Utility Department pursuing these designs without first obtaining written approval from CDOT, (b) what is the City’s plan for flood mitigation if CDOT maintains its position that there can be no above-ground structures within its right-of-way, and (c) is the City looking at alternatives; if so, what are the alternatives? 4. Why are there no costs or mention of Viele Channel in any of the documents provided to WRAB or City Council, when discharging water detained behind the flood control structure requires that the Viele Channel undergo an extensive rehabilitation effort to remove vegetation and sediment in order to minimize the risk of flooding if this channel overflows? What are the approximate costs for that work? 5. How were the acreages of Threatened and Endangered Species Habitat determined that are shown on Table 2 in the April WRAB information packet? How many acres of Prebles Meadow Jumping Mouse habitat and how many acres of Ute Ladies’ Tresses Orchid habitat are included for each option? How many of those acres are associated with the floodwall compared to the earth fill? 6. Since the April WRAB information packet states on page 78 that FEMA issued a Letter of Map Revision for the Highway 36 widening, does this mean that FEMA has approved Highway 36 as a flood control structure; if so, why does the design propose building a floodwall parallel to the highway?

    Frances asked about 2 months ago
    1. Two separate sets of regulatory standards apply to the project, one for the floodplain and one for dam safety and design. Regulatory standards for floodplain mapping and flood mitigation do not require an allowance for climate changeHowever, city staff are evaluating if and how a voluntary climate change allowance might be incorporated into the design. The state engineer’s office has regulatory jurisdiction over the dam structure and does require a climate change allowance for design of high hazard damsand such an allowance is being incorporated into the South Boulder Creek flood mitigation design. 

     

    1. The best way to identify structures currently located in a floodplain is through the City’s flood hazards mapProposed projects currently identified in each drainage are included on the city’s flood information webpageAttachment C to the April 20, 2020 Water Resources Advisory Board materials (page 209 of 242) provides cost estimates related to the broader Stormwater and Flood Management Utility. Each drainageway is evaluated through a “lifecycle” of mapping, mitigation planning, design and construction and each drainageway is at a different point in the lifecycle. Therefore, existing mitigation cost estimates for all drainages in the city are a work in progress and potentially understate the overall actual need. Updated cost estimates for the various drainageways are continuously being developed and will be a topic included in the Comprehensive Flood and Stormwater Master Plan update taking place in 2020 and 2021. 

     

    1. The city has held preliminary discussions with CDOT about the project but won’t be able to obtain more definitive determinations until staff presents the alternative council chooses and enough associated design work, including hydraulic analysis at the US36 bridge, for their input and review. As with any project, the city would need to reevaluate the proposed flood mitigation approach if required permits or approvals were denied. 

     

    1. Maintenance of Viele channel is included in the ongoing Stormwater and Flood Management Utility as one of the 16 major drainage ways in Boulder and is planned for irrespective of the flood design project. Post construction, the Viele channel would be maintained as required to provide adequate capacity for the flood mitigation outlet works. 

     

    1. Current environmental impacts were estimated by overlaying existing Geographic Information Systems (GIS) data, including environmental information and environmental surveys of the project area, with the proposed project footprint(s)The table below provides a summary of the resulting environmental impacts, including the impacts to Threatened and Endangered species habitat. The work done to date is adequate for comparison purposes at the conceptual design level and will be further refined as design proceeds. 

    Potential Environmental Impacts 

    Project Alternative 

    Wetlands 

    (acres) 

    Open Water 

    (acres) 

    Total Open Water and Wetlands 

    (acres) 

    Total Threatened and Endangered Species Habitat 

    (acres) 

    Option 1 

    (100-yr) 

    4.8 

    2.6 

    7.4 

    0.9 

    Option 2 

    (500-yr) 

    7.1 

    2.6 

    9.7 

    5.0 

    Option 3 

    (200-yr) 

    8.9 

    2.6 

    11.5* 

    5.0 

    Note: Figures are rounded to the nearest 1/10th of an acre 

    * Placement of fill is considered an impact in USACE 404 permitting, whereas inundation with water is not considered an impact. Because fill placement is unique to each of the alternatives based on the non-inundated property available, the 200-yr storm has more land available for fill, including more wetlands, thus the larger area of impact.    

    1. US 36 is not an approved flood control structure. The FEMA letter associated with the highway widening documents changes to the SBC floodplain resulting from the US36 widening project. These changes do not prevent US36 from overtopping during a 100-yr flood and do not provide flood benefits for the West Valley area that the proposed flood mitigation project is designed to protect.  

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    During the a recent city council study session, city council members expressed concerns based on staff comments that CDOT might not approve plans for 500-year protection because of increased SBC flows under the US 36 bridge. Council members stated such concerns were a major reason for rejecting the 500-year plan. In the past, there was grievous miscommunication between the city staff and CDOT regarding the use of CDOT right-of-way along US 36. I therefore made requests to city staffmembers Joe Taddeucci and Brandon Coleman for hard evidence that CDOT would not approve the 500-year plan. I also requested such information from CDOT, including a formal CORA request to CDOT. I have received nothing that would support city staff's statements that CDOT might not approve the 500-year plan. In fact, the City’s report states that the 500-year plan may not cause any negative impacts. "The 108-inch-diameter outlet would increase peak flows through the US36 bridge by about 6 percent but would not cause additional flooding downstream of South Boulder Road. It is possible that the increases in flow through the bridge may not cause negative impacts (i.e., scour) or that negative impacts could be mitigated by installing scour protection through the bridge." Please provide hard evidence that CDOT would not approve plans for protection from a 500-year flood.

    B. Binder asked about 2 months ago

    Asking permitting agencies to speculate in writing about specifics of what they might or might not approve before such detail is available to do so would be a dramatic departure from normal project process and would not be conducive to efficient agency approvals. If such out-of-process documentation will be a requirement of the project going forward, staff would not recommend proceeding. Conditions that will be fundamental to approval for any alternative presented to CDOT involving the US36 bridge cannot be met for the 200- and 500-year flood levels.  

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    What is included in "total project cost?" Are Phase 2 and 3 included? Is long-term maintenance included? What is counted as an "environmental impact?

    Harlin asked about 2 months ago

    The project costs include costs for construction of Phase 1 from the South Boulder Creek Master Plan. This includes the direct costs of constructing the flood mitigation structure (detention facility), the earth fill cost to provide 129 acres of PUB land use area, and estimated cost of impacts to existing university facilities. These line items in the table below are delineated because earth fill is not required for the flood mitigation protection but needed to offset land use impacts from creation of flood detention. 

    Opinion of Probable Construction Cost 

     

    Project Components 

    Option 1 

    (100-yr) 

    Option 2 

    (500-yr) 

    Option 3 

    (200-yr) 

    Regional Flood Detention 

    $41M 

    $47M 

    $46M 

    Earth Fill 

    $10M 

    $34M 

    $32M 

    SubTotal 

    $51M 

    $81M 

    $78M 

    CU Impacts (1) 

    $15M 

    $15M 

    $15M 

    Total 

    $66M 

    $96M 

    $93M 

    Note: Figures have been rounded to the nearest million dollars 

    (1) Includes impacts to CU Tennis Courts, South Loop Drive, Warehouse, Utilities Connections, Recreation FieldsEstimated costs/impacts will be refined as the flood mitigation project progresses through the design process and finalized through the annexation process  

     

    Long term operation and maintenance would typically be estimated at 0.5% to 1% per year of initial construction cost of dam features and is not included in cost tables but is within the margin of accuracy of the estimatesAll alternatives would have similar features and would require similar maintenance. 

     

    Environmental impacts are based on the project footprint (area underneath a design element) over ecologically sensitive areas (i.e., threatened and endangered species habitat, wetland, etc.). The disturbance area used for the project footprint includes an allowance for construction access and staging. Any additional construction access roads and staging areas, if needed, would be determined once a design concept is selected and construction drawings and specifications are developed. 

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    How will transportation access to the site be decided? Will Tantra lakes be consulted? Will CDOT be consulted? When will this happen?

    PLAN Boulder County asked about 2 months ago

    A multi-modal transportation and access study will be completed prior to annexation to determine necessary improvements, appropriate points of access, performance standards (e.g., trip budget) and other related topics. City staff will coordinate with CDOT during and after the study and each impacted neighborhood will be consulted throughout that process. We anticipate the transportation study being completed after the flood mitigation project is selected in June 2020, given that the different concepts impact the site differently (e.g., perimeter access points).  

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    What information (beyond verbal statements) does Boulder have from CDOT regarding their willingness to accept either the 100 or 500-year designs?

    PLAN Boulder County asked about 2 months ago

    Asking permitting agencies to speculate in writing about specifics of what they might or might not approve before such detail is available to do so would be a dramatic departure from normal project process and would not be conducive to efficient agency approvals. If such out-of-process documentation will be a requirement of the project going forward, staff would not recommend proceeding. Conditions that will be fundamental to approval for any alternative presented to CDOT involving the US36 bridge cannot be met for the 200- and 500-year flood levels.  

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    The purpose of this page is "to give the Boulder community an opportunity to ask questions and share thoughts related to flood project trade-offs, design or flood design." I appreciate the opportunity but am worried that there is not a wider net for seeking public input. The responses here are thorough but not intelligible for a lay audience. The format of the online Q and A, which requires online access, registration, and passwords excludes people in our community. Where is the opportunity for regular people (ie. not scientists, not people who have been following the issue for 3-25 years) to engage in input and questions on this issue? How can we invite more voices into this conversation?

    Boulder Citizen asked about 2 months ago

    The current proposed project on CU South is a highly complex project involving multiple landowners, a unique annexation, numerous permitting agencies, substantial cost, and significant environmental considerations. Conversations surrounding this topic can quickly get complicated. General project information is likely best accessed through the respective project websites, which are linked to this Be Heard Boulder pageor through direct inquires to staff 

    The South Boulder Creek Flood Mitigation Project builds upon seventeen years of previous studies, community input, board recommendations and council decisions. There have been various forms of outreach and education during that time, including in-person meetings, mailings, online meetings and forums all intended to reach the broadest range of participants. This outreach process has been informed by city council representatives through a process subcommittee and all comments and questions received here will be provided to city council in advance of their June 16, 2020 meeting where they are anticipated to take action on the flood mitigation project.  

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    Who will pay for transportation improvements on the site? How much will CU contribute?

    PLAN Boulder County asked about 2 months ago

    We do not yet know what transportation improvements will be required on the site. The applicant will complete multi-modal transportation and access study prior to annexation to determine necessary improvements, appropriate points of access, performance standards (e.g., trip budget) and other related topics. Applicants, in this case the university, are generally responsible for improvements resulting from a proposed development plan. We anticipate the transportation study being completed after the flood mitigation project is selected in June 2020, given that the different concepts impact the site differently (e.g., perimeter access points).  

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    Why aren't the stronger storms and more frequent storms predicted by climate change used in the the models and choices? Historic flows are used in the models. What would be the costs and advantages of condemning the CU property? What are the details of the costs that the city would owe CU that Pomerance suggests in his Daily Camara article on 2-20-20 could cost over $100 million ("Boulder to pay for a long list of costs, including infrastructure, access to south Boulder’s already congested streets, liability associated with floods, and lots more").

    3ouzel asked about 2 months ago

    Two separate sets of regulatory standards apply to the project, one for the floodplain and one for dam safety and design. Regulatory standards for floodplain mapping and flood mitigation do not require an allowance for climate change. However, city staff are evaluating if and how a voluntary climate change allowance might be incorporated into the design. The state engineer’s office has regulatory jurisdiction over the dam structure and does require a climate change allowance for design of high hazard dams, and such an allowance is being incorporated into the South Boulder Creek flood mitigation design. 

    Regarding condemnation, as a threshold issue, there is a question whether the city could condemn the property. The law regarding one government condemning the property of another is not settled. Whether a home rule city can condemn the property of a state university has not been addressed by the Colorado courts. If permitted, the city would be required to pay the fair market value for any property taken. 

    Utilities projects typically provide compensation to property owners for project impacts. In the case of CU South, the proposed project has potential impacts to the university’s existing tennis courts, a warehouse, and South Loop Drive, among others. Compensation for these impacts will be addressed through CU South annexation negotiations and in alignment with Boulder Valley Comprehensive Plan Guiding Principles for the CU South property. Impacts to transportation and utilities are typically addressed by the applicant paying Plant Investment Fees to the city to offset the increased usage of roads and utility service. 

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    Many residents of Marshall believe that annexation is not possible, therefore you will return to the drawing board and consider the condemning our community and homes. This has been proposed by the city before. We are not city residents yet are subject to its home- rule, so have no representation. Is condemnation of private property upstream of CU South under consideration by any entity?

    SarahR asked about 2 months ago

    Condemnation of private property upstream of CU South is not under consideration by any entity – nor is it likely. The current proposed project on CU South is a highly complex project involving multiple landownersa unique annexation, numerous permitting agencies, substantial cost, and significant environmental considerations. Iseventeen years of related planning and analysis, South Boulder Creek has consistently been identified as a high priority and the city has not found any alternative to the current proposed project that has a better chance of navigating the project challenges and tradeoffs and providing the identified flood protection need  

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    Why hasn't the City official Color prepared on official about a State Environmental Review and/or National Environmental Policy Act review?

    Harlin asked about 2 months ago

    project footprint and associated impacts are needed for these types of reviews to occurThe project team can develop these details and begin formal regulatory permitting processes after a flood level alternative is chosen for design, which is anticipated in June 2020. To date, city staff has initiated high-level discussions with permitting agencies so they are aware of the proposed project and can anticipate when they might receive a permit application.   

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    The raw data collected from the groundwater study was included in the OSBT meeting packet. Where is the analysis? Are citizens expected to analyze the data themselves? What does the data show?

    Harlin asked about 2 months ago

    The primary takeaway from the report is that existing groundwater levels vary from 2 to 22.5 feet across the site. Project engineers will use this data to design a conveyance system that replicates existing groundwater levels and flow patterns and that meets dam safety requirements. From an environmental perspective, replication of existing groundwater conditions is important in preserving wetlands.   

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    CU has been the biggest impediment to the timely implementation of South Boulder Creek flood mitigation plans. When CU purchased its flood prone depleted gravel pit in 1996, 220 acres were designated for Open Space and only 88 acres were designated for development. When CU purchased the property, the reclamation plan for the gravel pit included several large ponds and wetlands that would abate flooding. The reclamation plan did not include a 6,000' levee to divert floodwaters around the gravel pit onto neighboring properties, and the reclamation plan stated "After reclamation, the mine site will become suitable for wildlife habitat". In 1997, CU screwed the city by refusing to cooperate with the city to address known flooding problems and by using its political clout to revise the gravel pit reclamation plan to "accommodate maximum potential development". Against strong objections from both the City and the County, CU revised the reclamation plan to eliminate ponds and riparian areas which would abate flooding and by adding a 6,000' levee around its gravel pit to divert floodwaters onto neighboring properties. As a result, when the 2013 flood hit, the depleted excavated gravel pit was dry while the Frasier Meadows Retirement Community and hundreds of residences were flooded. In 2018, the City Council approved a flood mitigation option referred to as Variant 1, 500-year. The estimated cost for that option was $35 million. But CU's Frances Draper, placing a higher priority on maximizing development of CU's gravel pit than on protecting the lives and safety of Boulder Residents, wrote a letter to the city stating: "We are writing to you today to provide notice that the university, as the landowner, does not agree to Variant I 500. Neither of our organizations should expend further staff or financial resources to continue to pursue Variant I 500." Instead of standing up to CU's bullying, the city directed its staff to come up with alternatives to meet CU's demands. Such plans now include decreasing flood protection to downstream residents in order to provide CU 129 acres (52 city blocks) of land out of the floodplain, and importing 1.3 million cubic yards of fill at a cost of $34 million to replace the sand and gravel removed from CU's gravel pit in order to raise the land out of the floodplain. The total cost of that plan is $96 million, up $61 million from the Variant 1 500-year plan approved in 2018. CU teaches classes on environmental design and continually uses the words resilient and sustainable to describe its activities. But CU's activities on CU South violate the most basic fundamental principles of sound environmental design. Instead of caving in to CU's bullying and extortion, why doesn't the city let the world know about these activities and shame and embarrass the university into doing the right thing, which is allowing the city to use the land it needs to protect its citizens' lives and property from flooding?

    B. Binder asked about 2 months ago

    Policy guidance for CU’s future annexation plans is set by the Boulder Valley Comprehensive Plan CU South guiding principles, a document that was approved following extensive public process and a 4-body review in 2017. The guiding principles and 2019 direction from city council are the criteria staff are following for evaluation of flood design levels and developable acreage for CU.  

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    The purpose of this page is "to give the Boulder community an opportunity to ask questions and share thoughts related to flood project trade-offs, design or flood design." I appreciate the opportunity but am worried that there is not a wider net for seeking public input. The responses here are thorough but not intelligible for a lay audience. The format of the online Q and A, which requires online access, registration, and passwords excludes people in our community. Where is the opportunity for regular people (ie. not scientists, not people who have been following the issue for 3 years) to engage in input and questions on this issue? How can we invite more voices into this conversation?

    Boulder Citizen asked about 2 months ago

    The current proposed project on CU South is a highly complex project involving multiple landowners, a unique annexation, numerous permitting agencies, substantial cost, and significant environmental considerations. Conversations surrounding this topic can quickly get complicated. General project information is likely best accessed through the respective project websites, which are linked to this Be Heard Boulder pageor through direct inquires to staff 

    The South Boulder Creek Flood Mitigation Project builds upon seventeen years of previous studies, community input, board recommendations and council decisions. There have been various forms of outreach and education during that time, including in-person meetings, mailings, online meetings and forums all intended to reach the broadest range of participants. This outreach process has been informed by city council representatives through a process subcommittee and all comments and questions received here will be provided to city council in advance of their June 16, 2020 meeting where they are anticipated to take action on the flood mitigation project.  

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    What happens if the City annexes CU South and then the University sells the property to someone else? What happens to the development entitlements bestowed by the City?

    PLAN Boulder County asked about 2 months ago

    The annexation will be accompanied by an annexation agreement. The agreement will state any terms and conditions on the property to ensure that the annexation does not create an unreasonable burden on the physical, social, economic or environmental resources of the city. The agreement will “run with the land,” meaning that the allowances for development would apply regardless of ownership.  

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    The City of Boulder’s annexation and zoning process in governed by municipal code sections 9-2-17 and 9-2-18 and Colorado Revised Statutes 31-12-108 which lay out formal requirements for public notice, public hearings, and preparation of an annexation report. When and how will these formal processes be undertaken?

    PLAN Boulder County asked about 2 months ago

    Annexation agreement negotiations will be guided by the CU South Guiding Principles and an annexation process that provides opportunities to influence the annexation terms through city boards and the City Council meetings. The schedule and process for these meetings will be further refined once a South Boulder Creek flood mitigation design level is chosen, which is anticipated in June 2020.   

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    One of the major issues confronting this annexation is the fact that CU has presented only vague plans for development in nothing like the sort of detail the City would normally require. Why is this annexation being treated differently?

    PLAN Boulder County asked about 2 months ago

    This annexation is unique for several reasons: 

    1. The property is owned by the university. As a state entity, CU Boulder is generally not subject to the city’s development regulations. However, the annexation agreement can include terms and conditions that determine how the site is used in the future. 

     

    1. There is no site plan. Annexation applications are typically accompanied by a site plan that describes how the site is proposed to be developed. The university will not have a site plan for CU South for several years. In lieu of a site plan, the annexation agreement will include standards and conditions that regulate future uses and built form (e.g., building height, public trails) with an emphasis on mitigating impacts to nearby properties. 

     

    1. Flood mitigation is the primary driver of the project. The university has committed to convey to the city up to 80 acres of the site for construction of a flood mitigation project or to be used for open space mitigation related to the project. However, the land is only available if and when the entire CU South property is annexed. In other words, the flood mitigation project and annexation must happen together. 

     

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    This project will require the disposal of Open Space property. How will this disposal be handled to maintain compliance with specific requirements regarding disposal in the City Charter?

    PLAN Boulder County asked about 2 months ago

    Any disposal would follow the process in Section 8-8-11, B.R.C. 1981, which provides “any transfer of open space lands from the Open Space and Mountain Parks department to any other department of the city will for the purpose of the Charter be made only after compliance with the requirements of Section 177 of the Charter.”  

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    After 2013 the City vowed to do better with flood protection and codified this intent in the 2015 Comprehensive Plan. CU South offers one of the first opportunities to implement this yet the City is settling for 100-year rather than 500-year protection, leaving thousand more citizens in harms way. All Boulder citizens are going to pay for this flood protection. Why is the City abandoning guidance earned from the harsh experiences of 2013? How has this been justified to the thousands of residents who are not protected under the 100-year proposal?

    PLAN Boulder County asked about 2 months ago

    City staff presented a summary of three Variant 1 alternatives with differing flood protection levels associated with the 100-yr, 200-yr, and 500-yr storm events at the February 25, 2020 City Council Study Session. Although City Council does not make formal recommendations at study sessions, council indicated a preference for the design to proceed with the 100-yr flood protection alternative. The Variant 1 100-yr alternative was found to have the least environmental impacts, the lowest cost, and was identified to have the greatest probability of permitting feasibility through the various regulatory agencies. When taken as a whole, the 100-yr project design has the highest likelihood of successfully navigating project constraints, including funding. City Council is scheduled to make a formal recommendation on the South Boulder Creek (SBC) Flood Mitigation project at its June 16, 2020 meeting.  

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    How will the City prioritize flood mitigation given there are needs in every drainage?

    PLAN Boulder County asked about 2 months ago

    The 2004 Comprehensive Flood and Stormwater Master Plan document currently guides floodplain management and a process to update this master plan began in January of this year. Thupdate will include development of prioritization criteria for Stormwater and Flood Management Utility projects and programsStaff anticipates this update process to take approximately 18 months and will include significant public engagement.   

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    When will the City get estimates on the costs of flood mitigation in other drainages in Boulder that were impacted by 2013?

    PLAN Boulder County asked about 2 months ago

    South Boulder Creek is one of 16 major drainages running through Boulder. Each drainage has its own flood mitigation projects and associated funding needs that are identified through a “lifecycle” of mapping, mitigation planning, design and construction. Currently, each drainageway is at a different point in the lifecycle. Existing mitigation cost estimates for all drainages in the city are a work in progress and potentially understate the overall actual need. Updated cost estimates for the various drainageways are continuously being developed and will be a topic included in the Comprehensive Flood and Stormwater Master Plan update being updated in 2020 and 2021. Proposed and active stormwater and flood projects across the city can be found here  

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    To lessen he ecologica impact of the revised Variant 1 project, can the following be provided: (a) a dam design that places most or all of the foundation underneath and downstream of the main flood wall; (b) a foundation design that is less obstructive to groundwater movement, e.g., a pier/caisson design rather than a typical cutoff wall to bedrock; (c) a design for a robust groundwater maintenance and monitoring system; (d) a design for the dam and monitoring system that puts most or all inspection access behind the structure; (e) construction process designed to minimize upstream impacts on OSMP land, e.g., excavating, transporting, staging and constructing from within the flood wall footprint or the downstream side; and (f) for other project designs,, consideration of similar approaches?

    Edie Stevens asked about 2 months ago

    The project is committed to minimizing and/or avoiding environmental and ecological impacts. The foundation and groundwater design will be based on the design flood protection level and depth of detained flows and will require review and approval by the State of Colorado dam safety division prior to being constructed. Design features that could minimize environmental impacts are construction of a groundwater conveyance system described above, limiting the floodwall extent in designated Preble’s meadow jumping mouse habitat, or limiting construction staging areas in size and in sensitive areas, among others. The groundwater system, foundation design and construction approach will be further developed during preliminary design after council provides direction on a flood protection level at their June 16, 2020 meeting.   

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    What will be the cost for restoration of each acre of OSMP land subject to ponding under the 100-year storm event with the constructed project?

    KT asked about 2 months ago

    Specific costs would be determined in conjunction with Open Space and Mountain Parks (OSMP) during the preliminary design of the flood project and are variable to site. OSMP staff recommended a working project cost contribution of $100,000 per acre for restoration of inundated area above the 100-yr floodplain in the July 11, 2018 OSBT memo.  

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    Have you done a cost/benefit analysis of the various proposed SoBoCreek mitigation measures versus the mitigation measures for the other tributaries affected by the 2013 flood? A c/b analysis would presumably look at the cost of the improvements versus the future damage avoided. I realize that the plans are not complete for all the other tributaries, but they can be estimated, and presumably the damage that occurred that could be avoided is already known. Also, have these been totaled, so that the SoBoCreek costs and benefits could be compared to total costs and benefits from doing mitigation on the other creeks, so that the scale of the two can be compared?

    Steve P asked about 2 months ago

    We don’t currently have a citywide cost benefit comparison for the 16 drainageways. Each drainageway is evaluated through a “lifecycle” of mapping, mitigation planningdesign and construction that does not readily lend itself to a city-wide cost/benefit comparison since each drainageway is at a different point in the lifecycle and since there are many other factors that impact the viability of projects besides costs and benefits. However, regardless of whether it is cost benefit or some other selection criteria, South Boulder Creek would come out as a high priority because of the identified flood risk, flood benefits from the project, damage experienced during the 2013 flood and direction from City Council.   

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    Have you done a legal analysis to examine wether the use of Flood Control Utility fees may be expended under TABOR for such things as CU Tennis Courts, fill dirt to allow CU to expand its footprint, road improvements for access to CU South, etc.? If so, where it this accessible to the public?

    Steve P asked about 2 months ago

    City staff have consulted with city attorneys related to South Boulder Creek funding. It is common practice for the city to pay for items that are impacted by utilities projects. Flood project expenses are related to an ongoing CU South annexation negotiation between the city and the university. Any utility funds used will be spent in accordance with TABOR and the requirements of the City Charter.  

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    What is the bonding capacity of the Flood Control Utility? How does this compare to the mitigation costs of doing South Boulder Creek/CU South versus doing the mitigation on the rest of the tributaries that were affected by the 2013 flood?

    Steve P asked about 2 months ago

    All Stormwater and Flood Management Utility capital projects are funded primarily by monthly user charges, with additional funding from Plant Investment Fees and the Mile High Flood District (MHFD) – the city’s regional funding partner. Projects with costs that exceed the cash reserves in the Stormwater and Flood Management Utility fund are typically funded through 20-year term revenue bonds. The annual debt service payments associated with such bonds are costs factored into utility rates through the annual budget process. Therefore, broadly speaking, the city’s bonding capacity is limited by the city’s willingness to approve utility rate increases that result from bond debt services payments.  

    High levels of investment in a single Stormwater and Flood Management Utility project or program would generally result in less funds available for other stormwater and flood CIP projects throughout the city. Existing mitigation cost estimates for all drainages in the city are a work in progress and potentially understate the overall actual need. Updated cost estimates for the various drainageways are continuously being developed and will be a topic included in the current Comprehensive Flood and Stormwater Master Plan update. 

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    Could we please have a side-by-side analysis and comparison of the benefits and costs between the revised Variant I (one that uses OSMP land, instead of CDOT land, for the floodwall) and an upstream option which would capture enough flow upstream and west of the CU-South property to eliminate the What is the City’s plan for flood mitigation if CDOT maintains its position that there can be no above-ground structures within its Rt 36 right-of-way? Is the City looking at an upstream alternative, like using the hole in the ground that already exists in the natural flood plain?

    C Thompson asked about 2 months ago

    Technical information on storage upstream of the currently proposed project will be discussed at the June 3 Open Space Board of Trustees (OSBT) meetingThe flood mitigation project is currently in a conceptual design phase. The city has begun preliminary discussions with CDOT about the project but won’t be able to obtain definitive determinations until an alternative is selected and enough design work is completed to allow the city to submit a permit application. As with any project, the city would need to reevaluate the proposed flood mitigation approach if required permits or approvals were denied.  

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    How much will it cost to remove the CU levee? And how much will it cost to restore the underlying land?  Out of which Department’s budget will each of these costs be paid ?

    KT asked about 2 months ago

    The existing levee is located on property owned by CU Boulder. Costs for removal of the levee or any cost savings through use of the material for the flood project are being negotiated as part of the related CU South Annexation. Although the levee does not impact the functionality of the flood mitigation design, there are environmental considerations associated with levee that will be discussed at the June 3 Open Space Board of Trustees meeting and at the June 16 City Council meeting. The flood project, which will be funded by the city, will incorporate any potential costs or savings associated with the levee as more is known about the CU South Annexation.   

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    To what extent has a land swap with CU been explored? Should negotiations with the University break down, what plans are there for keeping residents and properties safe in the event of a flood? Could a land swap be considered in the future so as to expedite the flood mitigation process?

    Amy asked about 2 months ago

    City Council had an initial discussion about a potential "land swap" during its Feb. 25, 2020 Study Session. That discussion focused on a large area known as “Area III – Planning Reserve”, which is about 500 areas of land in North Boulder on the north side of US36 (area around and including Atlas Flooring and the Gateway Park Fun Center). Although council recognized that the Planning Reserve concept might have potential when looked at separate from other factors, when considered alongside impacts to the flood mitigation timeline, the university’s interests, and impacts to other city priorities, the idea seemed less of a viable option. Specifically, the university indicated that they are unable to realistically consider the Planning Reserve as a potential alternative without the land first becoming eligible for annexation (which could take several years). The Planning Reserve was not deemed a realistic alternative because of related delays to the flood mitigation process and the numerous unknown factors in the review process for the Planning Reserve.   

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    Where can I find the data on groundwater flows and impacts to endangered species?

    Amy asked about 2 months ago

    The Phase 1 Geotechnical Report and a Groundwater Data Collection Update with the most recent groundwater data will be provided to the OSBT in their May 13, 2020 board packet. Additional information and analyses will be provided in the board packet and presentation for the June 3, 2020 OSBT meeting. A conceptual discussion of the groundwater system is included in Section 5.3.3 of the Attachment C of the February 25 Study Session memo (Pages 78-79 of 191). 

    The following table provides a summary of the estimated permanent environmental impacts, including the wetlands and open water impacts that will be evaluated by the US Army Corps of Engineers (USACE). 

    Potential Environmental Impacts 

    Project Alternative 

    Wetlands 

    (acres) 

    Open Water 

    (acres) 

    Total Open Water and Wetlands 

    (acres) 

    Total Threatened and Endangered Species Habitat 

    (acres) 

    Option 1 

    (100-yr) 

    4.8 

    2.6 

    7.4 

    0.9 

    Option 2 

    (500-yr) 

    7.1 

    2.6 

    9.7 

    5.0 

    Option 3 

    (200-yr) 

    8.9 

    2.6 

    11.5* 

    5.0 

    Note: figures are rounded to the nearest 1/10th of an acre 

    * Placement of fill is considered an impact in USACE 404 permitting, whereas inundation with water is not considered an impact. Because fill placement is unique to each of the alternatives based on the non-inundated property available, the 200-yr storm has more land available for fill, including more wetlands, thus the larger area of impact.    

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    To what extent has an upstream detention solution been studied? What are future plans for studying such an option?

    Amy asked about 2 months ago

    Technical information on storage upstream of the currently proposed project will be discussed at the June 3 Open Space Board of Trustees (OSBT) meeting.   

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    Why don't you follow the BVCP recommendations of 500 yr, mitigation, upstream detention and Natural Areas protection ? Do you understand that the actual cost is inclusive of $40M for the COB to move dirt so CU can retain the use of 129 acres rather than the 80 they would have otherwise? Do you know that the actual costs of a 500 yr. mitigation are of better long term economic benefit in lives and structures than a 100 yr. which only appears less expensive? Do you understand the level of potential extreme weather events possible from diversion of funds from climate change mitigation that could wreck havoc on Boulder, considering the lack of anticipation of a 1000 yr. rain in 2013 and the profound and unprecedented impact on the lives and economy of the entire world from COVID 19 with an all time high of 2900 deaths in one day in the US 1 wk. ago, 1/3 of the cases in the world and 1/4 of the deaths in the world, attributed to the US with only 5 % of the world's population? Planning Board and CIty Council both supported a 500 yr. event option. This all changed at a CIty Council Study Session on 25 Feb. when staff was redirected in their workplan to a 100 yr. option intentionally bi-passing a weigh-in at a regular City Council meeting where the public has a say. Do you think this presents a problem reflected in a $750,000 Tipton Report that puts the staff in the middle of a public policy debate between the Council and the public in a no-win situation that actually impairs the financial stability of the very City that pays your salaries and in the middle of an economic tremor unlike ever seen before? Do you understand the impact of CU's failure in developing their plans to permit the process for the City to move forward more quickly to lift the risk to the very public it is beholden to? And this has been 20 yrs of a great cumulative amount of funding including the 2013 flood that laid waste to Boulder as a result, so who do you think is responsible for this? Lynn Segal 404-447-3216 24/7 lynnsegal7@hotmail.com

    lynn segal asked about 2 months ago

    The Boulder Valley Comprehensive Plan guiding principles relate to both the flood mitigation project and related CU South annexation and contain information relevant to many of your questions. Regarding the flood mitigation project specifically, city staff presented a summary of three Variant 1 alternatives with differing flood protection levels associated with the 100-yr, 200-yr, and 500-yr storm events at the February 25, 2020 City Council Study Session. Although City Council does not make formal recommendations at study sessions, council indicated a preference for the design to proceed with the 100-yr flood protection alternative. The Variant 1 100-yr alternative was found to have the least environmental impacts, the lowest cost, and was identified to have the greatest probability of permitting feasibility through the various regulatory agencies. City Council is scheduled to make a formal recommendation on the South Boulder Creek (SBC) Flood Mitigation project at its June 16, 2020 meeting.   

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    Why do you ask respondents to rank aspects which may have no interest to us? Poor questionnaire! I am only concerned about immediate forward action on flood mitigation -- get going on this, finally!

    Kay D. Forsythe asked about 2 months ago

    At the February 25, 2020 City Council Study Session, city staff presented a summary of three Variant 1 alternatives with differing flood protection levels associated with the 100-yr, 200-yr, and 500-yr storm events. Although City Council does not make formal recommendations at study sessions, council indicated a preference for the design to proceed with the 100-yr flood protection alternative. The Variant 1 100-yr alternative was found to have the least environmental impacts, the lowest cost, and was identified to have the greatest probability of permitting feasibility through the various regulatory agencies. City Council is scheduled to make a formal recommendation on the South Boulder Creek (SBC) Flood Mitigation project at its June 16, 2020 meeting. In preparation for the June meeting and at council’s request, city staff are seeking board and public input. The topics used for the questionnaire were identified during the latest update to the Boulder Valley Comprehensive Plan and are part of the university's annexation application.  

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    Why did the WRAB information packet for the 4/20 meeting fail to mention that the OSBT requested a significant evaluation that includes a side-by-side analysis and comparison of the benefits and costs of the revised Variant I and an upstream option? On page 22, the OSBT’s September 2019 requests are described simply as ‘information requirements the Board would first need [before considering] a disposal motion,’ not imperatives that needed to be addressed prior to OSBT’s decision about disposal.

    Magdalena asked about 2 months ago

    The WRAB meeting materials including notification of the June 3 Open Space Board of Trustees (OSBT) meeting, which will include discussion of storage upstream of the currently proposed project. The Open Space Board of Trustees will not consider disposal and any associated conditions until after a project alternative is chosen by council, which is anticipated in June 2020.   

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    Why can't you Get moving on option 1, to save lives?

    Sara asked about 2 months ago

    City Council is scheduled to make a formal recommendation on the South Boulder Creek (SBC) Flood Mitigation project at its June 16, 2020 meeting. In preparation for the June meeting and at council’s request, city staff are seeking board and public input. In the interim, the project is advancing preliminary design activities related to the Variant 1 configuration including phase 2 geotechnical investigations and hydraulic modelling.   

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    Why is the cost of fill and other expenses associated with making CU’s property suitable for development included with the flood mitigation project? Will these costs be included in the stormwater fee increase? How can we justify paying for infill with City stormwater fees?

    PLAN Boulder County asked about 2 months ago

    The soil fill is an indirect cost related to flood mitigation. The city Utilities Department does not own the land or have utility easements for the proposed flood project. The university owns a portion of the property. In 2017, the city and university agreed to the Boulder Valley Comprehensive Plan Guiding Principles. Earthfill costs are included in the current project alternative analysis and tradeoff summary because fill would be needed to offset inundation impacts from creation of flood detention. The final cost and funding sources for earthfill will be the subject of further evaluation and negotiation as the project proceeds.  

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    Where is the questionnaire?

    Harlin asked about 2 months ago

    All Boulder residents are invited to complete the questionnaire. To complete the ranking portion of the questionnaire, go to “Rank Annexation” button located under the timeline on the Be Heard page, then click “Complete Questionnaire.” Question #1 will appear with several options beneath it. There is a dropdown box directly to the left of each option, the box has a small downward pointing arrow on it. Click on that, then select the number (or ranking) that you want that option to have with “1” being the highest and “10” being the lowest. If you selected “other” because you believe another option should be considered, simply type your response in the box provided. When you are finished, click on “Submit” at the bottom of the page and your responses will be saved.     

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    This response: How do I state my choice of an option and then highest priority? Thank you el godrick asked 5 days ago. How do I access the questionnaire? Do all Boulder citizens have an opportunity to fill out the questionnaire?

    Boulder Citizen asked about 2 months ago

     

    All Boulder residents are invited to complete the questionnaire. To complete the ranking portion of the questionnaire, go to “Rank Annexation” located under the timeline on the Be Heard page, then click “Complete Questionnaire.” Question #1 will appear with several options beneath it. There is a dropdown box directly to the left of each option, the box has a small downward pointing arrow on it. Click on that, then select the number (or ranking) that you want that option to have with “1” being the highest and “10” being the lowest. If you selected “other” because you believe another option should be considered, simply type your response in the box provided. When you are finished, click on “Submit” at the bottom of the page and your responses will be saved.

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    Do you know about the significance of the flash flood that roared down Dowdy Draw in the early evening of 9/13, "jumped" S. Boulder creek just west of highway 93 and was the major contributer to the already saturated dry creek drainage that parallels S. Boulder creek? If not, send me an e-mail as my hiking group walked he whole area in the several weeks after the flood and can document that there were two streams of more or less equal size north of highway 93. The northern branch came around the margin of the CU berm and was the major contributor to the massive damage the area west of Foothills Parkway and N of highway 36. I have reported this to the planners of the flood mitigation dam. The 100-year Variant 1 plans are quite sufficient and the council should recognize their responsibilities to the residents in that area and stop further obfuscation by the noisy minority of the Hate CU group.

    Pete Palmer asked 2 months ago

    The Doudy Draw watershed was a major contributor to South Boulder Creek flow in 2013Current City of Boulder floodplain mapping shows the overflow of HWY 93 that you describe and that occurred during the 2013 flood. Community members who wish to share records of past flood events can contact staff here.  

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    I have three related questions about the cost of earth fill: (1) Why is earth fill that would provide CU with 129 acres of developable land included in the cost that the Utility Department will have to issue a bond for - this fill has no benefit for flood protection, so why should the cost be borne by the Stormwater and Flood enterprise fund of the Utility Department? (2) Since the fill allows CU to develop, isn’t this a broader community benefit that should be covered by the City’s General Fund or some other fund? (3) If the cost of earth fill were removed from project costs, there is only a $6M difference in costs between the 100-year and 500-year designs, and the 500-year design saves more people, structures, and dwellings from flooding - why wasn’t the cost/benefit to people, structures and homes presented to WRAB and the public?

    Frances asked 2 months ago

    The soil fill is an indirect cost related to flood mitigation. The city Utilities Department does not own the land or have utility easements for the proposed flood projectThe university owns a portion of the property. In 2017, the city and university agreed to the Boulder Valley Comprehensive Plan Guiding Principles, which provide for developable land by the university in any acceptable flood alternative. Therefore, earthfill costs are included in the current project alternative analysis and tradeoff summary because fill would be needed to offset land use impacts from creation of flood detention. The future funding source for project components such as fill will be the subject of further evaluation and negotiation as the project proceeds. 

     

    A breakdown of probable construction costs associated with each alternative is shown below and was included in the April 20, 2020 Water Resources Advisory Board (WRAB) meeting materials (Page 29 of 242) and page 31 of these materials provides information on structures, people and dwellings protected.  

     

     

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    What does the line that say " CU Impacts" mean? Is any tax payer money going to CU for this flood mitigation project? Where is there consideration of the impact to surrounding neighborhoods (not only downstream)? How will the environmental impacts be mitigated in a satisfactory manner? What did we learn from the critical studies of ground water, surface water flows, topography, soil characteristics, geo-technical issues, wildlife and habitat inventories that were asked fro last July? What alternatives exist for proceeding with the damn work without annexing the CU property?

    Boulder Citizen asked 2 months ago

    All Stormwater and Flood Management Utility capital projects are funded primarily by monthly user charges, with additional funding from Plant Investment Fees and the Mile High Flood District (MHFD) – the city’s regional funding partner. Projects with costs that exceed what is available in the Stormwater and Flood Utility fund are typically funded through 20-year term revenue bonds. The annual debt service payments associated with such bonds are costs factored into utility rates through the annual budget process.  

    Utilities projects typically provide compensation to property owners for project impacts. In the case of CU South, the proposed project has potential impacts to the university’s existing tennis courts, a warehouse, and South Loop Drive, among othersCompensation for these impacts, and consideration of impacts to surrounding neighborhoods, will be addressed through CU South annexation negotiations and in alignment with Boulder Valley Comprehensive Plan Guiding Principles for the CU South property.   

    Environmental Impacts from the project will be addressed as part of the permitting process and in coordination with the city’s Open Space and Mountain Parks department. All mitigation for environmental impacts must meet the requirements of the regulatory agencies including the US Army Corps of Engineers for wetlands and waters of the US and the US Fish and Wildlife Service for Threatened and Endangered Species.  

    The Phase 1 Geotechnical Report and a Groundwater Data Collection Update with the most recent groundwater data will be provided to the OSBT in their May 13, 2020 board packet (posted around May 7, 2020 here). Additional information and analyses will be provided in the board packet and presentation for the June 3, 2020 OSBT meeting.  

    In addition to using available historic groundwater data, the South Boulder Creek flood mitigation project has collected groundwater and surface water data since Feb 2018. Project engineers are using this data to generate three baseline groundwater models to represent non-irrigated, irrigated and transition conditions. After existing conditions are modeled for each of these distinct groundwater “seasons”, design on a groundwater conveyance system that maintains the existing conditions can begin. A conceptual discussion of the groundwater system is included in Section 5.3.3 of the Attachment C of the February 25 Study Session memo (Pages 78-79 of 191).  

    A portion of the land needed for flood mitigation is owned by the university. The land needed for flood mitigation is only available if and when the entire CU South property is annexed. There are no options to proceed with the flood mitigation dam without annexing CU South according to the Boulder Valley Comprehensive Plan guiding principles associated with the project 

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    Two questions: (1) It appears that another benefit of the 500-year design is that it would allow Highway 36 to not be overtopped and remain open following a wider range of floods. Why was this benefit not presented to the public and not factored into the discussions on the level of flood design? (2) In the WRAB’s April meeting packet, the Executive Summary stated that the cost increase of the project would be about $8.75/month for a single-family residence. Why was this cost stated in the April meeting as being $10/month? What would this cost be if the costs of the earth fill were excluded?

    Frances asked 2 months ago

    1) Both the 100-yr and 500-yr conceptual designs would meet the project goal of preventing overtopping of US 36 during their respective flood events. The 100-yr flood design would reduce, but not prevent US36 from overtopping in a 500-yr storm event, which is an event of greater magnitude with less probability of occurringTradeoffs related to the proposed project alternatives are presented in the Water Resources Advisory Board meeting materials (page 31 of 242). 

    2) Project costs presented to WRAB at the April 20, 2020 meeting reflect total project costs and a range of potential increases of which $10 is the midpoint for the 100-yr flood mitigation designRate increases related to South Boulder Creek flood mitigation, including how and when to apply annual debt service payments associated with project bonds, will be determined annually through the budgeting process. There is currently no indication that the earthfill costs can be separated from the flood mitigation project costs as the earthfill addresses impacts to the property owner from the flood mitigation project. Evaluation of funding for project components such as fill will be the subject of further evaluation and negotiation as the project proceeds.  

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    How do I state my choice of an option and then highest priority? Thank you

    el godrick asked about 2 months ago

    To complete the ranking portion of the questionnaire, go to “Rank Annexation” and then click on “Complete Questionnaire.” Question #1 will appear with several options beneath it. There is a dropdown box directly to the left of each option, the box has a small downward pointing arrow on it. Click on that, then select the number (or ranking) that you want that option to have with “1” being the highest and “10” being the lowest. If you selected “other” because you believe another option should be considered, simply type your response in the box provided. When you are finished, click on “Submit” at the bottom of the page and your responses will be saved.   

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    OSBT has requested the engineering plans and modeling analyses to show that the historic underground flow will be maintained in the OSMP State Natural Area (especially in the 90 acres near Highway 36) in wet, dry, and flood years, including the maintenance and operation of any structures proposed for doing this in perpetuity. Will these plans and analyses be provided to OSBT in a timely manner before their June 3 meeting, so that OSBT can make an informed recommendation?

    Edie Stevens asked 2 months ago

    The Phase 1 Geotechnical Report and a Groundwater Data Collection Update with the most recent groundwater data will be provided to the OSBT in their May 13, 2020 board packet (posted around May 7, 2020 here). Additional information and analyses will be provided in the board packet and presentation for the June 3, 2020 OSBT meeting.  

    In addition to using available historic groundwater data, the South Boulder Creek flood mitigation project has collected groundwater and surface water data since Feb 2018. Project engineers are using this data to generate three baseline groundwater models to represent non-irrigated, irrigated and transition conditions. After existing conditions are modeled for each of these distinct groundwater “seasons”, design on a groundwater conveyance system that maintains the existing conditions can begin. A conceptual discussion of the groundwater system is included in Section 5.3.3 of the Attachment C of the February 25 Study Session memo (Pages 78-79 of 191).  

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    How and when will impacts to high quality ecosystems and listed species be informed by consultations with the USFWS and USACE to determine ways of avoiding or minimizing adverse impacts to OSMP resources and listed species? And will USFWS and USACE approval of any mitigation plan be required? If not, why not?

    Edie Stevens asked 2 months ago

    The flood mitigation project would have both regulatory requirements and requirements imposed by the OSBT to compensate for impacts to city open space land and resources. Although the respective interests may be similar, the two are not intrinsically related. The OSBT and City Council can independently assess and determine impacts without the involvement of an outside permitting agency. Regulatory permitting for the South Boulder Creek Flood Mitigation can begin once an alternative is chosen for design, which is anticipated in June 2020. The project will likely require a U.S. Army Corps of Engineers 404 permit which would involve a Section 7 or Section 10 formal consultation with the U.S. Fish and Wildlife Service.   

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    How will the proposed flood mitigation structures be designed and constructed to minimize impacts to OSMP lands and critical habitat:

    Edie Stevens asked 2 months ago

    Requirements to minimize impacts to open space lands and critical habitat that may be provided by the OSBT and the City Council will be factored into the preliminary design of the flood mitigation project. Design features that could minimize environmental impacts are construction of a groundwater conveyance system, limiting the floodwall extent in designated Preble’s meadow jumping mouse habitat, or limiting construction staging areas in size and in sensitive areas, among others. More specific environmental mitigation measures could also be determined as a condition of the Open Space Board of Trustees, by City Council or as determined in the preliminary design and permitting phase of the project.  

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    can the City buy back the property? what are CU's options if annexation is turned by the city? is annexation a done deal? why is the flooding issue the most prominent at this time when there are other issues that may be more significant? thank you

    gordon reese asked 2 months ago

    The CU South property is owned by the University of Colorado Boulder and is not for sale. The university has committed to conveying up to 80 acres of the site to the city for construction of a flood mitigation project or to be used for open space mitigation related to that project. The land needed for flood mitigation is only available if and when the entire CU South property is annexed. In other words, the flood mitigation project and annexation must happen together. The flood mitigation design will ultimately inform how other issues are addressed as part of the annexation (e.g., access points, were future development may occur).   

    A decision on annexation is not a done deal. City Council will ultimately consider whether to annex the property. The site would remain in the unincorporated county if not annexed. More information on the CU South annexation is located here 

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    Considerable flooding west of South Boulder Creek, approximately where Dry Creek Ditch #2 is located, was shown by the project flow model. How much water is this, and what percentage of a given flood event? Why has the City not looked into ways of capturing this flood water as part of the flood mitigation?

    rbridge asked 2 months ago

    The proposed flood design concept is designed to capture floodwaters at the lowest point in the floodplain located south of US36 at the West Valley Overflow and would capture all the flows you describe.    

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    When I was on the OSBT on 2014, that first approved option D, we were told that a 72 hour elimination was part of the plan. There seems to be a disconnect here now, as it is not in the literature. I said at the time that was the only reason I would vote for it, in that condition, if the flood draining happens no later than 72 hours. By that time all the rare plants and species would be unable to recover from this type of flooding and we would lose this rare area protected for over 50 years by the state natural grassland.

    Molly Davis asked 2 months ago

    The proposed flood mitigation design would discharge any detained flood waters from a 100-yr flood within approximately 24 hours and does not anticipate any additional environmental impacts from inundation. Colorado water law provides for longer detention times as needed. Specifically, within 72 hours for storms smaller in magnitude than a 5-year storm, and within 120-hrs for storms of magnitude 5-year or greater, however the project does not anticipate operating within these extended time frames.   

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    Regarding the proposed groundwater conveyance system, can the City provide examples of where this system has been installed at other sites, especially sites similar to CU-South in which the conveyance system will need to work equally well for ambient groundwater levels and for water levels 10-15 feet higher when the dam is full of water?

    Molly Davis asked 2 months ago

    The proposed groundwater conveyance system includes a collection trench filled with permeable material and conveyance piping that are based on fundamental engineering principles. These principles are routinely applied in management of groundwater and seepage in modern earthen embankment dams, in water supply systems, and in environmental remediation and treatment. The South Boulder Creek flood project will design a groundwater conveyance system to work for both ambient groundwater conditions and temporary flood detention conditions. To address ambient groundwater conditions, the project team is studying the existing groundwater conditions around the project site and will model the proposed project to confirm that existing groundwater conditions are maintained. The system will also be designed to safely manage groundwater to meet dam safety requirements in the detention scenario. The State of Colorado dam safety division will review and approve the design prior the project being constructed.   

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    Construction of a flood wall or other flood mitigation structures on Open Space will require a disposal, since flood control to protect development in a floodplain is not an Open Space Charter purpose. To justify a disposal, a car net benefit is a prerequisite. What would be the clear net benefit and losses to OSMP lands that sgihykd guide this disposal decision?

    Edie Stevens asked 2 months ago

    The possible costs and benefits of any project impact to open space is a consideration for the Open Space Board of Trustees and the City Council in their deliberation regarding any potential disposal of property. Costs can be more specifically determined once a conceptual design for the project is decided on, but include such issues as: loss of Preble’s meadow jumping mouse habitat; loss of Ute ladies’ tresses orchid populations; loss of high quality wetland habitat; and loss of designated state natural area acreage, as well as scenic and agricultural impacts. Benefits that could help guide any such decision include offsets such as: acquisition and long-term protection of additional acres of open space and restoration of the ecological functioning of lower quality open space land.  

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    1. Construction of a flood wall or other flood mitigation structures on Open Space will require a disposal, since flood control to protect development in a floodplain is not an Open Space Charter purpose. To justify a disposal, a clear net benefit is a prerequisite. What would be the clear net benefits and losses to OSMP lands that should guide this disposal decision? 2. The OSBT has requested a side-by-side analysis and comparison of the benefits and costs of the revised Variant I (that uses OSMP land, instead of CDOT land, for the floodwall) and an upstream option which would capture enough flow upstream and west of the CU South property to eliminate the need for a floodwall to bedrock on OSMP land. That upstream variation would place minimally invasive structures to guide the flood flows in one or more places west of Highway 93 to Highway 36. Will this analysis be provided to OSBT in a timely manner before their June 3 meeting? If not, how can OSBT make an informed recommendation? Also, why was the WRAB asked to decide on the level of flood protection provided by the Variant 1 dam without being able to first review the results of the OSBT’s requested comparison of Variant 1 with an upstream option? 3. OSBT has requested the engineering plans and modeling analyses to show that the historic underground flow will be maintained in the OSMP State Natural Area (especially in the 90 acres near Highway 36) in wet, dry, and flood years, including the maintenance and operation of any structures proposed for doing this in perpetuity. Will these plans and analyses be provided to OSBT in a timely manner before their June 3 meeting, so that OSBT can make an informed recommendation? 4. How will the proposed flood mitigation structures be designed and constructed to minimize impacts to OSMP lands and critical habitat? 5. How and when will impacts to high quality ecosystems and listed species be informed by conversations with the USFWS and USACE to determine ways of avoiding or minimizing adverse impacts to OSMP resources and listed species? And will USFWS and USACE approval of any mitigation plan be required? If not, why not?

    Michael Browning asked 2 months ago

    Q1:  

    Construction of a flood wall or other flood mitigation structures on Open Space will require a disposal, since flood control to protect development in a floodplain is not an Open Space Charter purpose. To justify a disposal, a clear net benefit is a prerequisite. What would be the clear net benefits and losses to OSMP lands that should guide this disposal decision?  

    A1 

    The possible costs and benefits of any project impact to open space is a consideration for the Open Space Board of Trustees and the City Council in their deliberation regarding any potential disposal of property. Costs can be more specifically determined once a conceptual design for the project is decided on, but include such issues as: loss of Preble’s meadow jumping mouse habitat; loss of Ute ladies’ tresses orchid populations; loss of high quality wetland habitat; and loss of designated state natural area acreage, as well as scenic and agricultural impacts. Benefits that could help guide any such decision include offsets such as: acquisition and long-term protection of additional acres of open space and restoration of the ecological functioning of lower quality open space land. 

    Q2:  

    The OSBT has requested a side-by-side analysis and comparison of the benefits and costs of the revised Variant I (that uses OSMP land, instead of CDOT land, for the floodwall) and an upstream option which would capture enough flow upstream and west of the CU South property to eliminate the need for a floodwall to bedrock on OSMP land. That upstream variation would place minimally invasive structures to guide the flood flows in one or more places west of Highway 93 to Highway 36. Will this analysis be provided to OSBT in a timely manner before their June 3 meeting? If not, how can OSBT make an informed recommendation? Also, why was the WRAB asked to decide on the level of flood protection provided by the Variant 1 dam without being able to first review the results of the OSBT’s requested comparison of Variant 1 with an upstream option?  

    A2:  

    An analysis of potential upstream variations that could meet the criteria requested by the Open Space Board of Trustees (OSBT) at their September 11, 2019 meeting will be provided in the board packet (posted here around May 28, 2020) and in the presentation for its June 3, 2020 meeting 

    The board and public engagement approach was determined by the council process subcommittee and involves soliciting focused feedback from relevant boards on matters within their purview. The purpose of the April 20, 2020 Water Resources Advisory Board (WRAB) meeting was to ask whether the WRAB had any updates to their July 18, 2018 recommendation and to request feedback on funding. The April 20, 2020 recommendation that council move the Variant 1 100-yr flood protection alternative to preliminary design aligned with WRAB’s previous recommendation for the SBC Flood Mitigation project.  

     

    Q3:  

    OSBT has requested the engineering plans and modeling analyses to show that the historic underground flow will be maintained in the OSMP State Natural Area (especially in the 90 acres near Highway 36) in wet, dry, and flood years, including the maintenance and operation of any structures proposed for doing this in perpetuity. Will these plans and analyses be provided to OSBT in a timely manner before their June 3 meeting, so that OSBT can make an informed recommendation?  

    A3:  

    The Phase 1 Geotechnical Report and a Groundwater Data Collection Update with the most recent groundwater data will be provided to the OSBT in their May 13, 2020 board packet (posted around May 7, 2020 here). Additional information and analyses will be provided in the board packet and presentation for the June 3, 2020 OSBT meeting 

    In addition to using available historic groundwater data, the South Boulder Creek flood mitigation project has collected groundwater and surface water data since Feb 2018. Project engineers are using this data to generate three baseline groundwater models to represent non-irrigated, irrigated and transition conditions. After existing conditions are modeled for each of these distinct groundwater “seasons”, design on a groundwater conveyance system that maintains the existing conditions can begin. conceptual discussion of the groundwater system is included in Section 5.3.3 of the Attachment C of the February 25 Study Session memo (Pages 78-79 of 191).  

    Q4:  

    How will the proposed flood mitigation structures be designed and constructed to minimize impacts to OSMP lands and critical habitat?  

    A4:  

    Requirements to minimize impacts to open space lands and critical habitat that may be provided by the OSBT and the City Council will be factored into the preliminary design of the flood mitigation project. Design features that could minimize environmental impacts are construction of groundwater conveyance system described above, limiting the floodwall extent in designated Preble’s meadow jumping mouse habitator limiting construction staging areas in size and in sensitive areas, among others. More specific environmental mitigation measures could also be determined as a condition of the Open Space Board of Trustees, by City Council or as determined in the preliminary design and permitting phase of the project. 

    Q5:  

    How and when will impacts to high quality ecosystems and listed species be informed by conversations with the USFWS and USACE to determine ways of avoiding or minimizing adverse impacts to OSMP resources and listed species? And will USFWS and USACE approval of any mitigation plan be required? If not, why not? - Michael Browning 

    A5:  

    The flood mitigation project would have both regulatory requirements and requirements imposed by the OSBT to compensate for impacts to city open space land and resources. Although the respective interests may be similar, the two are not intrinsically relatedThe OSBT and City Council can independently assess and determine impacts without the involvement of an outside permitting agencyRegulatory permitting for the South Boulder Creek Flood Mitigation can begin once an alternative is chosen for design, which is anticipated in June 2020. The project will likely require a U.S. Army Corps of Engineers 404 permit which would involve a Section 7 or Section 10 formal consultation with the U.S. Fish and Wildlife Service.  

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    What are the impacts on groundwater levels and groundwater flow of the proposed floodwall along Highway 36, and how are the groundwater model results being checked?

    Molly Davis asked 2 months ago

    Project design criteria includes replication of existing groundwater flow patterns to prevent upstream groundwater mounding, drying up downstream wetlands and/or other potential adverse impactsIn addition to using available historic groundwater data, the South Boulder Creek flood mitigation project has collected groundwater and surface water data since Feb 2018. Project engineers are using this data to generate three baseline groundwater models to represent non-irrigated, irrigated and transition conditions. After existing conditions are modeled for each of these distinct groundwater “seasons”, design on a groundwater conveyance system that maintains the existing conditions can begin. All modelling and proposed designs are reviewed by city staff and consulting groundwater expertsA conceptual discussion of the groundwater system is included in Section 5.3.3 of the Attachment C of the February 25 Study Session memo (Pages 78-79 of 191).  

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    What are the impacts on groundwater levels and groundwater flow of constructing a barrier wall that surrounds the excavated land on the CU-South campus?

    Molly Davis asked 2 months ago

    Groundwater collection and conveyance is a fundamental feature of dams. The project is being designed so that there will be no impacts to groundwater levels and flows. The cutoff wall will include a filtered drain system to convey groundwater to match existing groundwater flow patterns to prevent upstream groundwater mounding, drying up downstream wetlands and/or other potential adverse impacts.  

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    What steps has the City taken to verify the accuracy of the flow amounts and inundation volumes used in the current designs, and what steps will the City take in the future to verify the hydraulic modeling? What confidence does the City have in those modeling results?

    Molly Davis asked 2 months ago

    City staff is currently working closely with a hydraulic modelling consultant with expertise in floodplain modeling and design. The hydraulic modeling software used for the project design is approved by FEMA and the City of Boulder as the regulatory model for floodplain mapping of South Boulder Creek. The 2013 flood impacts and extents were mapped following the flood and the results compared well to the modelling of existing flood flows and flooding extents. 

    Regarding future steps, city staff is considering developing an independent model using different software to allow for validation of the existing hydraulic modelling and faster modelling runs for design evaluation. 

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    OSBT has requested a side-by-side analysisand comparison of the benefits and costs of the revised Variant 1 (that uses OSMP land instead of CDOT land for the flood wall) and an upstream option which would capture enough flow upstream and west of the CU South property to eliminate the ned for a flood wall to bedrock on OSMP land. The upstream variation would place normally invasive structures to guide the flood flows in one or more places west of Highway 93 to Highway 3;6. Will this analysis be provided to OSBT in a timely manner before their June 3 meeting: If not, how can OSBT make an informed recommendation? Also, why was the WRAB asked to decide on the level of flood protection provided by the Variant 1 dam without being able to first review the results of OSBT's requested comparison of Variant 1 with an upstream option?

    Edie Stevens asked 2 months ago

    An analysis of potential upstream variations that could meet the criteria requested by the Open Space Board of Trustees (OSBT) at their September 11, 2019 meeting will be provided in the board packet (posted here around May 28, 2020) and in the presentation for its June 3, 2020 meeting.  

    The board and public engagement approach was determined by the council process subcommittee and involves soliciting focused feedback from relevant boards on matters within their purview. The purpose of the April 20, 2020 Water Resources Advisory Board (WRAB) meeting was to ask whether the WRAB had any updates to their July 18, 2018 recommendation and to request feedback on funding. The April 20, 2020 recommendation that council move the Variant 1 100-yr flood protection alternative to preliminary design aligned with WRAB’s previous recommendation for the SBC Flood Mitigation project.  

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    The WRAB information packet states on page 92 that the outlet piping that will discharge detained water will require 600 feet of tunneling under Highway 36 to connect to Viele Channel. What is CDOT’s opinion on this tunneling, when does the City expect to get a written response from CDOT on this, and what is the City’s plan if CDOT refuses to allow tunneling under the highway?

    Molly Davis asked 2 months ago

    The South Boulder Creek flood mitigation design will require Colorado Department of Transportation (CDOT) approval as both a permitting agency and property owner. In general, transportation agencies prefer tunneling or boring approaches for utility crossings. The city has no reason to believe the utility crossing required for the outlet piping would not receive CDOT approval. The city has begun preliminary discussions with CDOT about the project but won’t be able to obtain definitive determinations until an alternative is selected and enough design work is completed to allow the city to submit a permit applicationAs with any project, the city would need to reevaluate the proposed flood mitigation approach if required permits or approvals were denied.  

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    What is the estimated cost of removing the CU levee? How much will it cost to restore the underlying land? Where in the project budget will these costs appear – i.e. from what source will these costs be paid?

    rbridge asked 2 months ago

    The existing levee is located on property owned by CU Boulder. Costs for removal of the levee or any cost savings through use of the material for the flood project are being negotiated as part of the related CU South Annexation. Although the levee does not impact the functionality of the flood mitigation design, there are environmental considerations associated with levee that will be discussed at the June 3 Open Space Board of Trustees meeting and at the June 16 City Council meetingThe flood project, which will be funded by the city, will incorporate any potential costs or savings associated with the levee as more is known about the CU South Annexation.   

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    Based on public comments made at the July 2018 and April 2020 WRAB meetings, the public favors a 500-year level of flood protection. What weight is being given to the public’s views and how is the City staff factoring the public’s desires into its decision making? If the project is going to cost the City between $50 and 100 million, wouldn’t it be advisable to poll a statistically accurate sample to determine the public’s views?

    rbridge asked 2 months ago

    The South Boulder Creek Flood Mitigation Project has been evaluated with over seventeen years of studies, community input, board recommendations and council decisions. Staff appreciates the time community members have taken to provide feedback and attend engagement opportunities. Feedback on the level of flood protection has varied and is being provided to City Council in advance of its June 16, 2020 meeting to inform their decision about which flood mitigation alternative to move into preliminary design. At a February 25, 2020 Study Session, council indicated a preference for the 100-yr alternative when presented with conceptual design update, summary of project trade-offs and project feasibility information. Please see the public engagement schedule on this page or at the project webpage for opportunities to provide public feedback to City Council and the associated boards related to the project.    

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    Obtaining regulatory approval will present a significant challenge. When does the City propose to begin discussions with regulatory agencies?

    Edie Stevens asked 2 months ago

    Permitting for the South Boulder Creek Flood Mitigation can begin once an alternative is chosen for design, which is anticipated in June 2020. To date, city staff has initiated high-level discussions with permitting agencies so they are aware of the proposed project and can anticipate when they might receive a permit application  

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    When will we see a detailed side-by-side analysis and comparison of the benefits and costs of the 100-year plan with an upstream option that would capture enough flow upstream and west of the CU-South property to eliminate the need for a floodwall to bedrock on OSMP land or reduce that structure and its impacts?

    Frances asked 2 months ago

    Technical information on storage upstream of the currently proposed project will be discussed at the June 3 Open Space Board of Trustees (OSBT) meeting.   

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    There are major groundwater issues that affect the adjoining wetlands and that are important for the engineering concept evaluation. Critical wet meadow habitat upstream and downstream of US-36 depends upon uninterrupted groundwater flow, and loss of this rare ecotype due to groundwater disruption would be unacceptable under the OSMP Charter. So far, it has not been proven possible to create new, compensatory, wet meadow habitat. Consequently, we ask for monitoring study results or the results of modelling to show that groundwater issues have been fully considered and that the historic underground flow will be maintained in the OS lands and the State Natural Area in wet, dry, and flood years, including the maintenance and operation of any structures proposed for doing this in perpetuity.

    Frances asked 2 months ago

     

    In addition to using available historic groundwater data, the South Boulder Creek flood mitigation project has collected groundwater and surface water data since Feb 2018. Project engineers are using this data to generate three baseline groundwater models to represent non-irrigated, irrigated and transition conditions. After existing conditions are modeled for each of these distinct groundwater “seasons”, design on a groundwater conveyance system that maintains the existing conditions you describe can begin.  

    The proposed project alternative does anticipate permanent impacts to approximately five acres of existing Open Space property along US Highway 36. However, the project will mitigate all environmental impacts as part of the required permitting processes. Additionally, the project will work closely with Open Space and Mountain Parks staff and Trustees to ensure that the city’s open space values are met under any flood mitigation approach. 

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    Please provide detailed information about Environmental Impacts for all Options.

    MCLeggitt asked 2 months ago

    The environmental impacts for the current project configurations estimate a 90-foot wide construction footprint south of the floodwall on OSMP property and impacts from relocating the floodwall to outside of the existing US36 CDOT right-of-way. Temporary environmental impacts would be similar for all three options and would occur on OSMP property for construction of the floodwall. 

     Mitigating environmental impacts is key to project feasibility. Reducing or eliminating environmental impacts aligns with the BVCP Guiding Principles of protecting and where possible restoring wildlife habitat, grasslands, wetlands and streams within the 100-yr floodplain and in the Area Protected by Levee.  

     Table 2 provides a summary of the environmental impacts, including the wetlands and open water impacts that will be evaluated by the US Army Corps of Engineers (USACE). 

    Table 2: Potential Environmental Impacts 

    Project Alternative 

    Wetlands 

    (acres) 

    Open Water 

    (acres) 

    Total Open Water and Wetlands 

    (acres) 

    Total Threatened and Endangered Species Habitat 

    (acres) 

    Option 1 

    (100-yr) 

    4.8 

    2.6 

    7.4 

    0.9 

    Option 2 

    (500-yr) 

    7.1 

    2.6 

    9.7 

    5.0 

    Option 3 

    (200-yr) 

    8.9 

    2.6 

    11.5* 

    5.0 

    Note: Table 2 figures are rounded to the nearest 1/10th of an acre 

    * Placement of fill is considered an impact in USACE 404 permitting, whereas inundation with water is not considered an impact. Because fill placement is unique to each of the alternatives based on the non-inundated property available, the 200-yr storm has more land available for fill, including more wetlands, thus the larger area of impact.    

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    Please direct me to a map of the floodplain as it will exist after the mitigation project is completed. I'm in the Keewaydin Meadows neighborhood.

    G. George asked 2 months ago

    Figure 5.17 in Attachment C to the Feb 25 City Council Study Session memo (Page 115 of 191shows potential changes to the floodplain downstream of the project area for a 100-yr level flood protection. For the 500-yr and 200-yr flood protection, reference Figures 5.20 and 5.23 (pages 118 and 121) respectively. 

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    How was Project Feasibility determined in table presented to Council earlier this year?

    clancyph asked 2 months ago

     

    Project feasibility was determined based on a combination of permitting requirements, financial implications, ground disturbance and environmental and engineering considerations. Minimizing environmental impacts, including to threatened and endangered species habitat, and ensuring the project design is acceptable to approving agencies are key to project feasibility. When taken as a whole, the 100-yr project design has the highest likelihood of successfully navigating project constraints, including funding. 

     


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    WAAAY too much verbiage to find anything ... what is the URL showing the proposed design of Option 1?

    Buzz asked 2 months ago

    Good afternoon Buzz, please take a look at pages 11-13 of the memo from the Feb. 25, 2020 City Council Study Session. The memo is posted on the project web page under the heading City Council and Board Meetings. Click here to be taken directly to the project page.

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    The link in the first sentence in the first paragraph to https://bouldercolorado.gov/flood/south-boulder-creek-flood-mitigation-project does not work.

    Andrew Conley asked 2 months ago

    Thank you for letting us know. It's fixed and up and running.