To: Honorable Mayor and Members of Town Council
Through: David L. Corliss, Town Manager
From: Mark Marlowe, P.E., Director of Castle Rock Water
J. David Van Dellen, P.E., Stormwater Manager
Laura Kindt, P.E., Project Manager-Stormwater
Title
Resolution Approving a Service Agreement with Olsson, Inc., for the East Plum Creek/Sellers Gulch Confluence Project
Body
________________________________________________________________________________
Executive Summary
Castle Rock Water is seeking Town Council approval of a Resolution (Attachment A) approving a service agreement with Olsson Associates for the East Plum Creek (EPC)/Sellars Gulch Confluence Project in the amount of $647,754, plus staff requests a 10% Town-managed contingency in the amount of $64,775, for a total project authorization of $712,529. The East Plum Creek/Sellars Gulch Confluence Project is located in the heart of Downtown Castle Rock (see Attachment B) and will be funded through the Stormwater Fund. The scope of work generally includes survey, alternative analysis, preliminary and final design, environmental permitting and environmental approvals for stream stabilization improvements and regional water quality enhancement along EPC and Sellars Gulch. Project design and permitting is scheduled to be completed in fall of 2024. Additional funding partnerships through the Downtown Development Authority, Parks and Recreation, Chatfield Watershed Authority and grants will be pursued to determine if additional passive recreational uses are feasible within the project area.
Notification and Outreach Efforts
The Town will hold to open houses to present the proposed project improvements and solicit feedback. The Town will utilize the normal Town outreach channels including social media and email to notify the public of the open houses.
History of Past Town Council, Boards & Commissions, or Other Discussions
On January 6, 2009, Town Council passed, approved, and adopted a resolution approving the East Plum Creek Watershed Master Plan.
On January 6, 2009, Town Council passed, approved, and adopted a resolution approving the Sellars Gulch Drainageway Master Plan.
Discussion
The Confluence project is located near Downtown Castle Rock and is generally bounded by East Plum Creek Parkway to the south, I-25 to the west, Douglas County Buildings to the north and East Plum Creek Trail to the east. The Confluence Project has a unique opportunity to provides downtown soft surface trail networks and gathering areas with East Plum Creek and Sellars Gulch treated as an amenity and focal point. To date, there have been multiple studies completed for the project area, including master plans for East Plum Creek and Sellars Gulch, Transportation Plan and Downtown Alley Plan for adjacent streets. The drainage master plans recommend stabilizing the channels with the use of grade control structures. The East Plum Creek master plan recommends incorporating regional water quality and detention within the confluence area along with defined soft trails. The Transportation Plans and Downtown Alley Plans provide additional access points to the confluence.
Under existing conditions East Plum Creek and Sellars Gulch are experiencing bed degradation, bank erosion and constricted channels. The bank erosion is impacting water quality with the increased sediment entering the stream. The incision of the channel has lowered the water table, impacting the vegetation and trees ability to access water, resulting in loss of vegetation and trees. The majority of the project is within the Town’s Preble’s meadow jump mouse (PMJM) habitat and the Riparian Conservation Zone (RCZ) as identified within the Douglas County Habitat Conservation Plan. The Town of Castle Rock along with Colorado Department of Transportation (CDOT) utilize portions of the project area as PMJM mitigation. The loss of vegetation and trees have a direct negative impact on the PMJM habitat through loss of habitat.
This project will require coordination and easements with multiple property owners within the project area, including, Town of Castle Rock, Douglas County, CDOT, one private land owner, and one unknown property. This project will require coordination with United States Fish and Wildlife Service (USFWS), United States Army Corp of Engineers (USACE) for wetland and PMJM impacts and Federal Emergence Management Agency (FEMA) for hydraulic analysis of the streams and CLOMR/LOMR approval.
Staff has already engaged multiple stakeholders and internal departments to understand their future projects and goals within and adjacent to the project. Some of which include the CDOT, DDA, Parks (environmental and trails) and Public Works.
The goal of this project is to further refine and implement the drainage master plans while providing a design to be compatible with other stakeholder goals to the extent practicable, such as soft trails and the additional access points that may be included at a later date.
The Town issued a Request for Proposals (RFP) via Rocky Mountain BidNet, and five (5) responses were received. A selection committee, consisting of David Van Dellen and Laura Kindt, reviewed and ranked each proposal based on a weighted set of criteria included in the RFP document. Following the qualification based selection process, the fee schedule for each firm was opened and reviewed, “not for low bid, but for a reasonable and appropriate level of effort from each team member.” Barbara Spagnuolo and Kevin Tilson provided feedback on the proposals in regards to environmental and downtown development. The five fee schedules ranged from $569,887 to $746,000. The top ranked firm in terms of qualifications, response to scope of work, understanding of project and team experience was Olsson, whose proposal represented the best overall value for the services requested. The Olsson fee is within the staff estimate for engineering services and Olsson has developed a track record for successful projects along the East Plum Creek corridor with the Town over the past several years. Although this project was originally budgeted only for improvements on Sellars Gulch, staff determined that it would be most cost effective to include the East Plum Creek reach in this design and permitting effort given the proximity of improvements and the integrated nature of the open space corridor at the confluence of these two streams.
Budget Impact
Funds for this design agreement will be charged to the accounts below and will require a budget transfer from stormwater capital account 212-4475-444.75-52 which has a budget of $2,700,000 in 2023. Additionally, there is approximately $10 million available in capital reserves to complete this project and maintain other priorities in the coming year.
|
Fund |
Account Number |
Amount |
Cont. |
Total |
Budget |
|
Sellars Gulch |
212-4475-444.75-72 |
$161,938 |
$16,194 |
$178,132 |
$180,860 |
|
East Plum Creek |
212-4475-444.76-37 |
$485,815 |
$48,581 |
$534,396 |
$0 |
|
Total |
|
$647,754 |
$64,775 |
$712,529 |
|
Staff Recommendation
Staff recommends Town Council approval of a Resolution for approval of a services agreement with Olsson Associates for the East Plum Creek Reach/Sellars Gulch Confluence Project in the amount of $647,754, plus staff requests a 10% Town-managed contingency in the amount of $64,775, for a total project authorization of $712,529.
Proposed Motion
“I move to approve the Resolution as introduced by title.”
Alternative Motion
“I move to approve the resolution as introduced by title, with the following conditions: (list conditions).
“I move to continue this item to the Town Council meeting on _____ date to allow additional time to (list information needed).”
Attachments
Attachment A: Resolution
Exhibit 1: Service Agreement
Attachment B: Site Maps