HomeMy WebLinkAboutParklands AP Infrastructure Cert Letter LAND SURVEYING
July 11, 2025
City of Bozeman Engineering Department
Attn: Simon Lindley
20 East Olive Street
P.O. Box 1230
Bozeman, MT 59715
RE: Amended Plat of Lot 1, Block 1, The Parklands at Village Downtown Subdivision,
Existing Infrastructure Design Report Analysis & Findings
Simon,
As requested, Caddis Engineering & Land Surveying has conducted a review of the water, sewer
and storm water design reports previously prepared for the infrastructure that has been installed
to serve the proposed 8 lots on Lot 1, Block 1 of The Parklands at Village Downtown Subdivision.
Our review revealed a few discrepancies between the assumptions made in the original design
report and the proposed development on Lot 1. However, the differences are generally immaterial
with regards to validity of the design and the sufficiency of the existing infrastructure. The
following paragraphs are a summary of our findings and brief discussion of impacts.
Storm Water
The Stormwater Design Report prepared for the Parklands at Village Downtown, dated July of
2020, was reviewed and found to be valid for the proposed development of Lot 1, Block 1.
Drainage area boundaries, runoff coefficients and pond sizing calculations are consistent with the
proposed development. The existing infrastructure is sufficient, and no additional improvements
will be necessary to address storm water runoff from the project.
Water
A detailed model of the proposed (now existing) water system was included within the original
design report addressing system pressures and available fire flows. The original design report
assumed a development density of 11 dwelling units on Lot 1. The proposed density of 14-16
dwelling units is found to be inconsistent with the design assumption however the impact of this
discrepancy on the overall water system is believed to be minimal. The existing 8-inch diameter
water mains have a high degree of connectivity to the surrounding system with static pressures
around 140 psi and available fire flow of around 2,500 gallons per minute. The impact of an
additional 3-5 dwelling units on the highly networked existing water system serving a population
of approximately 57,000 users would be negligible. The pressure and available flows within the
existing mains and fire hydrants are more than sufficient to serve the development of 8-lots on
Lot 1.
406.581.4097 MCOTTERMAN(a)CADDISENG.COM PO BOX 11805.BOZEMAN, MT 59719 WWW.CADDISENG.COM
Sanitary Sewer
The previous sanitary sewer design report provided an analysis of the proposed 8-inch sewer
main installed to serve The Parklands along with an analysis of the downstream 21-inch Front
Street interceptor line. The sanitary sewer design report also assumed that Lot 1 would
eventually contain 11 dwelling units instead of the 14-16 dwelling units proposed. The design
report calculated a peak flow rate of 9.72 gallons per minute for The Parklands. The addition of
5 dwelling units would push the peak flow rate up to approximately 10.21 gallons per minute. An
8-inch sewer main flowing 75% full at minimum slope carries approximately 305 gallons per
minute. The existing sewer main is sufficiently sized to handle the proposed development.
The downstream "Front Street Interceptor Main" calculation found in the original design report
assumed the installation of a 21-inch main to handle the Parklands and all upstream sanitary
sewer flows. The"Front Street Interceptor Main"was installed in 2020, subsequent to the original
design report, with an actual main size of 24-inches. The installed 24-inch main has significantly
more capacity than the 21-inch main assumed with the design report and is therefore sufficiently
sized to handle the proposed development of Lot 1.
Caddis Engineering & Land Surveying certifies that the existing infrastructure installed to serve
Lot 1, Block 1 of the Parklands at Village Downtown is sufficient to serve the proposed Amended
Plat of Lot 1, Block 1 of said subdivision.
Should additional items come up in your review please don't hesitate to reach out for additional
information.
Sincerely, •��0 N T j N�a
oMatthew B. dp
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