On January 8, 2019 this item was tabled to review other areas of concern. As part of the Fiscal Year 2019 budget, Council adopted a Stormwater Capital Improvement Program that included several drainage improvement projects. The approved projects included drainage improvements associated with the White Rock Creek Drainage area. The White Rock Creek Drainage area is bounded by Belt Line Road in the north, Montfort Drive in the west and Addison's city limits to the east and south. Two projects were identified for this area, the first to add inlets to Montfort Drive and the second to add inlets to Oaks North Drive. These new inlets would connect to the existing stormwater system at both locations.
Criado and Associates, Inc., was selected to perform the design work for these projects. Criado was qualified through a Request for Qualifications process in 2017 to perform design, project management, and construction management related services for the Town. The original cost for design services for these projects was $48,160, with a scope of services that included:
- Design Phase Services - Engineer will gather necessary data to prepare detailed plans and specifications for the Town's review. Engineer will also perform survey and subsurface utility exploration services necessary to prepare plans. Engineer will also develop detailed construction cost estimates for the project.
- Bid Phase Services - Engineer will issue final plans and specifications for bidding. Engineer will answer any questions that arise during the bidding process, issue addenda, attend a pre-bid meeting, and prepare the bid tabulation and recommendation for contract award.
- Construction Phase Services - Engineer will hold a pre-construction meeting with selected contractor, complete weekly site visits throughout construction, respond to requests for information and submittals, attend the final project walkthrough, and prepare the project punch list.
Design began in October 2018. The Town's drainage criteria manual requires that new stormwater infrastructure be sized to manage the runoff from a 1% (100 year) storm event. During the detailed analysis of the existing storm system in Oaks North Drive, it was determined that the existing system does not have the capacity to accept the additional flows associated with the improvements (see Attachment A). The proposed improvements, therefore, would overload the existing system and water would surcharge out of the system, back on to the street.
The proposed change order incorporates additional design work to install new stormwater piping and appurtenances along Oaks North Drive to the drainage channel crossing, just south of Belt Line Road (see Attachment B). This new system will be sized in accordance with the Town's current drainage criteria manual. Criado will provide design, bid, and construction phase services, as described above.
Criado is also tasked with design services associated with the Montfort Drive storm drain improvements. The scope for this design included the installation of four new inlets adjacent to the Village on the Parkway Development. Staff proposes that the design associated with the Montfort Drive storm drain improvements be postponed because those improvements may be impacted by a potential redevelopment at Village on the Parkway. Once staff has a better understanding concerning whether the new development will move forward and how it will impact the stormwater infrastructure on Montfort, we will reassess how to proceed. The Town will receive a credit of $6,265 for this design work.
The total cost for this design change order is $35,555 for a total project cost of $83,715. This project, along with the updated design cost is budgeted for in the Stormwater Capital Projects Fund and design is expected to take four months to complete. |