HomeMy WebLinkAbout18 - Design Report - Residence Inn - Sewer
RESIDENCE INN - BOZEMAN
SEWER IMPROVEMENTS
SANITARY SEWER EXTENSION BASIS OF DESIGN REPORT
September, 2018
PREPARED BY:
MMI #: 5305.003
Table of Contents
INTRODUCTION ........................................................................................................................................... 1
1 PROBLEM DEFINED ........................................................................................................................... 1
2 DESIGN CONDITIONS ......................................................................................................................... 2
3 IMPACT ON EXISTING WASTEWATER FACILITIES ........................................................................ 3
4 PROJECT DESCRIPTION .................................................................................................................... 3
5 DESIGN CRITERIA .............................................................................................................................. 3
6 SITE INFORMATION ............................................................................................................................ 3
7 ENVIRONMENTAL IMPACTS .............................................................................................................. 3
8 OPERATION AND MAINTENANCE .................................................................................................... 3
APPENDICES
None
Prepared by:
Morrison-Maierle, Inc.
2880 Technology Blvd. W.
Bozeman, Montana 59771
Phone: (406) 587-0721
Fax: (406) 922-6702
Written By: MEE Checked By: JRN
Approved By: KDJ
PROJECT NO.: 5305.003
1
INTRODUCTION
This design report provides the criteria used as a basis of design for the Residence Inn Hotel
sewer main replacement project and is submitted in conjunction with the completed plans and
specifications. This report is organized following the outline recommended in DEQ-2, Chapter
10, Section 11.1, Engineering Reports.
The Residence Inn Hotel is located off of East Main Street on Lot 13A-1 of the Northern Pacific
Addition Subdivision. This project is located within the City of Bozeman, Montana. See the
vicinity map for location details.
1 PROBLEM DEFINED
This project involves the replacement of an existing 6-inch sewer main (located in East Main
Street) with approximately 340 feet of a new 8-inch sewer main. The Residence Inn Hotel will
be served by a 6-inch sanitary sewer service. The 6-inch sanitary sewer service will tie into the
new 8-inch main.
Sewer facilities included in this project will be designed in accordance with Montana Department
of Environmental Quality (MDEQ) regulations. Adequate capacity will be provided to allow for
growth in areas adjacent to the actual project areas. Flow and population data for the project
will be consistent with the City’s approved Facilities Plan, where applicable.
2 DESIGN CONDITIONS
The Residence Inn Hotel will be located on property zoned B-2 (Community Business District)
per the City of Bozeman’s zoning map. The capacity requirement for the sewer main extension
is calculated as follows:
Proposed Design Flows
The proposed East Main Hotel will have approximately 105 rooms. A guest occupancy rate of
1.5 guests per room is assumed which results in 158 guests when the hotel is 100% booked.
Based on the Montana Department of Environmental Quality’s Circular DEQ-4, Table 3.1-1
each guest typically generates 48 gpd, and each employee will generate 10 gpd. The 48 gpd
2
value includes normal hotel amenities and support facilities such as public restrooms, hotel and
guest laundry facilities, breakfast bars, small cocktail bars and other similar uses.
Assumptions:
• Proposed Hotel has 105 rooms
• Proposed Hotel guest occupancy rate of 1.5 guests per room = 158 guests
• Proposed Hotel will have approximately 5 employees
• Sewer Flow Rate = 48 gpd / guest (MDEQ Circular DEQ-4, Table 3.1-1)
• Sewer Flow Rate = 10 gpd / guest (MDEQ Circular DEQ-4, Table 3.1-1)
Guest Wastewater Flow Rate = (48 gpd)(158 guests) = 7584 gpd
Employee Wastewater Flow Rate = (10 gpd)(5 employees) = 50 gpd
Total Wastewater Flow Rate = 7,634 gpd or 5.3 gpm
Population = (158 guest) + (5 employees) = 163 people
Peaking Factor (PF) = (18+(population/1000)^.5)/(4+(population/1000)^.5)
Peaking Factor = 4.18
Peak Flow = 7,634 gpd (ave daily flow) x 4.18= 31,910 gpd
Peak Flow = 31,910 gpd = 22.16 gpm
Infiltration at Lot 1 = 150 gpd per Acre = 150 gpd x 1.74 (Lot 13A-1) acres = 261 gpd
Infiltration = 261 gpd = 0.18 gpm
Total Lot 1 flow = 22.16 gpm + 0.18 gpm = 22.34 gpm
Please refer to the table below for comparisons between maximum flows and proposed flows
and see that that proposed piping is adequate.
LOT PEAK FLOW (gpm) PROPOSED CONVEYANCE *MAXIMUM FLOW FOR 8” MAIN (gpm)
Hotel 22.34 Future 8-inch sewer main 346
*8-inch pipe at minimum grade (0.4%) with a roughness coefficient (n) value of 0.013
3
3 IMPACT ON EXISTING WASTEWATER FACILITIES
The existing sewer mains in the vicinity of this project can handle the increase in flows based on
information in the 2015 City of Bozeman Wastewater Collection Facilities Plan Update. The
2015 Plan did not identify this main as requiring upsizing with full buildout of its service area.
4 PROJECT DESCRIPTION
This project involves the replacement of an existing 6-inch sewer main (located in East Main
Street) with approximately 340 feet of a new 8-inch sewer main. The Residence Inn Hotel will
be served by a 6-inch sanitary sewer service. The 6-inch sanitary sewer service will tie into the
new 8-inch main.
5 DESIGN CRITERIA
Design criteria including average and peak flows as well as sewer depth information were
provided in previous sections. The proposed sewer main conforms to the State’s minimum
vertical and horizontal separation criteria from sewer mains.
The proposed conventional gravity sewer collection system is to be constructed to City of
Bozeman and the 6th Edition of Montana Public Works (MPW) standard specifications. In
particular, the sewer mains shall be 8-inch diameter SDR 35 Polyvinyl Chloride (PVC) pipe. All
manholes shall be standard concrete manholes spaced no more than 400 feet apart.
6 SITE INFORMATION
The project site has been zoned B-2 by the City of Bozeman. The existing site is bound by
Catamount Street to the South and East Valley Center Road to the North-East and an
undeveloped field to the West. The site has existing grades of less than 10% and Blackmore
Silt soil deposits (see the USDA Soil Survey information attached). The site is not located in a
floodway or floodplain.
7 ENVIRONMENTAL IMPACTS
There are no expected environmental impacts from this sewer main extension, as the City of
Bozeman Wastewater Treatment Plant has more than adequate capacity for this extension.
8 OPERATION AND MAINTENANCE
These sewer mains will be owned, operated, and maintained by the City of Bozeman.
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2880 Technology Boulevard West
Bozeman, MT 59718
Phone: (406) 587-0721
Fax: (406) 922-6702
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