Agenda Date: 03/2/2021
Subject:
Title
Resolution 11-2021: A resolution authorizing an amendment to an agreement between the City of Littleton and Mile High Flood District regarding final design and construction of drainage and flood control improvements for Little’s Creek at Gallup Street
Body
|
Prepared by: |
Carolyn R. Roan, Water Resource Manager |
PURPOSE:
Does Council support an amendment to an inter-governmental agreement (IGA) with Mile High Flood District (MHFD) for design and construction of drainage and flood control improvements for Little’s Creek at Gallup Street?
PRESENTATIONS:
Staff Presenter(s): Carolyn Roan, Water Resource Manager
Additional Presenter(s): N/A
SUMMARY:
Little’s Creek flows through Littleton from Broadway to the South Platte River, along Sterne Parkway, through Sterne Park, and through downtown.
The Mile High Flood District (f/k/a Urban Drainage and Flood Control District) and City of Littleton completed a flood hazard area delineation for Little’s Creek in 1977 and preliminary design report in 1978. Almost all improvements recommended by the design report have been completed in Littleton. At South Gallup Street, the report recommends a large culvert to replace the smaller culverts to reduce flooding of the roadway.
This location has typically experienced flooding of the roadway and adjacent properties once or more each year. Local residents have routinely contacted the city about this flooding. This project has been in planning for multiple years. Progress was delayed in 2016 due to the emergency repair of the collapsed culvert at Lee Gulch at Broadway. The Little’s Creek project remains a priority in the Storm Drainage Utility capital improvement plan. The original IGA included the culvert replacement and upstream stream stabilization through Angeline Little Greenway Park; however, the culvert has higher priority for construction.
The proposed box culvert at the intersection of South Gallup Street and West Peakview Avenue will limit the frequency of flooding on the roadway and surrounding properties, some of which are in the floodplain. The culvert will have capacity for a range of flood flows, but not the 100-year event, due to site constraints such as horizontal space and vertical limitations beneath the roadbed.
All other recommended improvements on Little’s Creek located within Littleton have been completed. The most recent improvements were on Sterne Parkway, between West Lake Avenue and South Windermere Street.
PRIOR ACTIONS OR DISCUSSIONS:
Council approved an IGA for this project in December 2015 (IGA No. 15-08.13) to initiate the engineering design. It was anticipated that this would be a multi-year project that required incremental funding to reach the total budget needed.
An IGA amendment (15-08.13A) for 2019 savings for this project was approved by City Council with Resolution 22-2019 on April 16, 2019, following a study session to clarify the project need. An IGA amendment (15-08.13B) for 2020 funding was approved by City Council with Resolution 18-2020 on May 19, 2020.
ANALYSIS:
Staff Analysis
The existing culvert on Little’s Creek at South Gallup Street is undersized and has very limited capacity for drainage. With a significant rainfall event, the stream frequently overtops the banks and the street floods. Proposed improvements call for a much larger culvert and channel transitions to convey stream flows. Additional storm sewer for local street drainage is anticipated to be constructed as part of this project. Extensive utility relocation, including water and gas mains, will also be needed. Staff has coordinated with utility companies such as Denver Water and Xcel Energy to undertake the necessary relocation in advance of the culvert project.
Design of the box culvert project is complete and a contractor is under contract with MHFD. This amendment of the agreement will provide the remaining funding needed for construction.
Construction will begin in spring 2021. MHFD will continue to manage the project, with Littleton assistance.
Council Goal, Objective, and/or Guiding Principle
Flood control improvements align with the desired community outcomes of Quality, Sustainable, Safe, and Natural community.
Fiscal Impacts
On large drainage and flood mitigation projects, the city partners with MHFD. Neither agency has enough funding available within a single budget cycle to fully fund these large projects. Therefore, each agency appropriates 50% of the funding for a given year, held by MHFD in a special fund, to save for total project costs.
Under the original 2015 IGA, $500,000 was set aside (50% from each agency). Another $500,000 was allocated in 2019 (50% from each agency) and the same in 2020. To date, approximately $400,000 has been spent on preliminary and final design, surveying, environmental investigation, private property flood mitigation study, engaging a contractor in a design-build arrangement, and other tasks. Construction and construction oversight costs are currently estimated at $1,900,000, for a total anticipated project cost of $2,300,000.
MHFD allocated $400,000 for this project in 2021, which the city will match if this IGA amendment (IGA No. 15-08.13C) is approved. Littleton’s contribution will come from the Storm Drainage Enterprise Fund and the Capital Projects Fund (for roadway and traffic calming improvements). The 2021 budget includes $240,000 for this project from the Storm Drainage fund and $160,000 for this project from the Capital Projects Fund.
MHFD and Littleton contribution amounts and percentages from each party under this IGA amendment are proposed as follows:
|
|
Percentage Share |
Total Contribution |
|
MHFD, 2015 |
|
$250,000 |
|
City of Littleton, 2015 |
|
$250,000 |
|
MHFD, 2019 |
|
$250,000 |
|
City of Littleton, 2019 |
|
$250,000 |
|
MHFD, 2020 |
|
$250,000 |
|
City of Littleton, 2020 |
|
$250,000 |
|
MHFD, 2021 |
50% |
$400,000 |
|
City of Littleton, 2021 |
50% |
$400,000 |
|
TOTAL |
100.00% |
$2,300,000 |
Alternatives:
If not approved, MHFD may allocate these funds towards another local government project and there would be an insufficient amount of funding accumulated to complete the construction. If delayed approval, the limited construction window will be missed this year. The city and MHFD have already invested significant funding for this project.
STAFF RECOMMENDATION:
Staff recommends approval of the amendment to the IGA, Agreement No. 15-08.13C.
PROPOSED MOTION:
Proposed Motion
I move to approve Resolution 11-2021 authorizing an amendment to the Intergovernmental Agreement between the City of Littleton and the Mile High Flood District regarding final design and construction of drainage and flood control improvements for Little’s Creek at Gallup Street.