HomeMy WebLinkAbout2.7.0_RESPONSE_Engineering Comments-DONE
July 31, 2020
Brian Krueger, Development Review Manager City of Bozeman Department of Planning and Community Development P.O. Box 1230
Bozeman, MT 59771-1230 Re: Bozeman East Mixed-Use Master Site Plan Review
COB#: 19230/19231 MMI#: 3959.022 Dear Brian: This letter is to provide written responses to the comments stated in the engineering review memo dated April 10, 2020. Below are our responses associated with each comment. ENGINEERING COMMENTS: General Comments
1. North 15th Avenue must be completed between Patrick Street and Tschache Lane prior to Site Plan approval. It appears the applicant will be pursuing concurrent construction for this work.
Note that the response to this comment from the original submittal was simply “Understood” and made no reference to the intention to pursue Concurrent Construction. Based on the concurrent construction request provided, Engineering is in support of concurrent construction
to complete Tschache Lane to the intersection of N 15th Ave and Tschache Lane. The concurrent construction request has been changed to include the construction of North 15th Avenue between Patrick Street and Tschache Lane.
2. The applicant must complete Tschache Lane to the intersection of North 15th Avenue and Tschache Lane prior to Site Plan approval. Note that the response to BMC Section
38.270.0360 in the Concurrent Construction request appears to indicate Tschache lane as being included in the request but the second paragraph of the main narrative does not. The applicant must clarify the intention in the first page of the Concurrent Construction request.
The concurrent construction request has been changed to include the construction of Tschache Lane. 3. Bozeman Municipal Code (BMC) 38.410.130. The applicant must provide the transfer of water rights or the payment of cash-in-lieu (CIL) of water rights prior to building permit
approval. Understood, we will coordinate with Brian Heaston to determine the CIL amount.
4. The applicant is advised that the proposed project falls within the Bozeman Solvent Site boundary. The property is underlain by an aquifer contaminated with perchloroethylene (PCE). The applicant has acknowledged that irrigation wells will not be dug as part of this
project. Additionally, excavations and associated dewatering may be impacted by PCE contaminated groundwater. Understood.
5. The applicant shall provide and file with the County Clerk and Recorder's office executed Waivers of Right to Protest Creation of Special Improvement Districts (SID’s) for the
following:
• Street improvements to Tschache Lane including paving, curb/gutter, sidewalk, and storm drainage
• Street improvements to N. 15th Avenue including paving, curb/gutter, sidewalk, and storm drainage
• Intersection improvements to Tschache and N. 19th Avenue The document filed shall specify that in the event an SID is not utilized for the completion of
these improvements, the developer agrees to participate in an alternate financing method for the completion of said improvements on a fair share, proportionate basis as determined by square footage of property, taxable valuation of the property, traffic contribution from the development,
cor a combination thereof. This is a condition of final plan approval. Understood. The owner would like to revisit signing the waiver of right to protest with the city once the preliminary site plan approval has been received, an unsigned copy
of the Waiver of Right to protest is included in this submittal. Stormwater Report 6. Note that the calculations provided for the orifice size were a direct copy from the original 1998 report. The DSSP utilizes a different equation. Modify the orifice calculation to meet City of Bozeman DSSP. The orifice calculation has been revised to meet the City of Bozeman DSSP and DEQ circular 8. Additionally, Sheet D-1 from the Bridger Peaks Town Center Record Drawing 1999 has been included to better illustrate the Pond Outlet Structure and design intention for Phase I/II and Future Detention (Detail 4/D-1) C600 Overall Site Grading and Drainage Plan
7. DSSP II.C.2 – Detention basins located in areas accessible to the public shall have a maximum water depth of 1 ½ feet and maximum basin depth of 2 ½ feet. Deep basins should
be fenced and placed in remote areas. A basin adjacent to Tschache Lane is not considered remote. Modify the pond depth to must meet City of Bozeman standards. Bozeman East mixed use site plan is located on Lot 5 of the Bridger Peaks Village
Subdivision J-368. Lot 5 was originally part of the Bridger Peaks Town Center PUD Subdivision development. The existing pond at the north-east corner of the Bozeman East site plan currently serves most of the Bridger Peaks Town Center PUD Subdivision. The
original design accounted for and was approved for both phase I and II along with future detention volumes (future being Lot 5). Per the Revised Drainage Design Report for the Bridger Peaks Town Center (1998), the pond is currently sized and built for Phases I and II which are currently constructed. With the remaining final phase, Bozeman East, the pond was designed to be enlarged to detain the fully developed conditions. The existing orifice structure has a release rate equal to the pre-development conditions of Phase I/II
therefore with the full buildout of the pond, the orifice will also need to be modified to control runoff under fully developed conditions.
The pond for Bridger Peaks Town Center Subdivision Phases I/II was built in 1999 before the city adopted depth standards for ponds. After speaking with Anna Russell regarding
the history of this development, she has allowed for the expansion of this pond to fulfill the full buildout of the Subdivision as well as for the pond to be fenced with consideration placed on the fencing material due to the proximity to the site access drive.
8. DSSP II.B.2 - Label existing and proposed contours on this and all grading sheets. Verification that all boundary grades tie-into adjacent properties was not possible without
contour labels. Existing and proposed contours have been labeled on all grading sheets.
9. BMC 40.04.700.A.4.a Requirements - It appears that the southeastern area of snow storage drains onto adjacent property. Regrade to prevent any off-site direct discharge of untreated stormwater and non-stormwater from development or redevelopment improvements.
The area of southeastern snow storage has been eliminated since that area would likely be unusable with parked vehicles per comment 12. Grades have been adjusted so stormwater and non-stormwater from the parking areas are collected and treated to prevent the
discharge of untreated stormwater. 10. The Phasing Plan needs to have a narrative associated with it describing storm drainage for each phase. A narrative has been added to accompany the Phasing Plan that describes the storm drainage for each phase
11. Tschache lane construction must be included in Phase I. This includes the sidewalk and boulevard. Remove the note to include dead end barriers on Tschache from EX-6 Master Site Plan; Tschache Lane will be constructed in Phase 1. Understood, the Phasing Plan will be revised to indicate the construction of Tschache Lane in Phase 1. 12. Note that the snow storage areas located behind parking stalls will likely be unusable with
parked vehicles. There is a concern that snow may be stored in the emergency turnaround for Phase I. Reexamine the snow storage for each phase and ensure adequate storage is provided. Snow storage behind parking stalls has been removed. The existing stormwater detention
pond will be expanded to serve the entity of Bozeman east as a part of Phase 1. This will eliminate the possibility of storing snow in the emergency turnaround as the majority of the snow will be stored in the detention pond area.
If you should have any questions regarding these comments, revisions and corrections for the Bozeman East Mixed-Use Site Plan Application don’t hesitate to contact me,
Celine Saucier, PE Project Engineer