HomeMy WebLinkAbout024 Stormwater Maintenance Plan811 W Mendenhall
SPR SUBMITTAL
811 W Mendenhall Apartments| BOZEMAN, MT, 59715
| STORMWATER MAINTENANCE PLAN 024
JOB NO. B23-026
MONTANA | WASHINGTON | IDAHO | NORTH DAKOTA | PENNSYLVANIA
JULY 2023
406.586.0277
tdhengineering.com
234 East Babcock Street
Suite 3
Bozeman, MT 59715
CLIENT ENGINEER
SMA Architecture & Design
428 E Mendenhall Street
Bozeman, MT 59715
TD&H Engineering
234 East Babcock Street, Suite 3
Bozeman, MT 59715
ON-SITE STORM WATER MAINTENANCE PLAN
811 WEST MENDENHALL APARTMENTS
BOZEMAN, MONTANA
811 West Mendenhall Apartments Storm Water Maintenance Plan
B23-026 1
811 WEST MENDENHALL APARTMENTS
STORM WATER MAINTENANCE PLAN
PURPOSE AND INTRODUCTION
This maintenance plan identifies the recommended maintenance procedures necessary for the
proper function of the on-site storm water management system proposed at the 811 West
Mendenhall Apartments project in Bozeman, Montana. For the purpose of this plan, nearly
100% of the site covered by a building with an internal parking garage and the on-site storm
water management system includes roof drains, area drains, drainage pipes, subsurface
retention chambers, and parking garage floor drains with a sand/oil separator.
All stormwater facilities at this site will be owned by the Landowner and the responsible party in
charge of all ongoing operation and maintenance of the on-site stormwater systems will be the
Landowner. The Landowner may delegate routine inspection and maintenance responsibilities
to the on-site facility operations management team, or may hire a qualified professional entity or
individual to perform certain monitoring and maintenance tasks as necessary. A log shall be
kept for all required inspections and maintenance. These logs shall be made available to the
City of Bozeman Public Works Department for review as requested. A sample maintenance log
is included in the attached Appendix.
STORM WATER MANAGEMENT SYSTEM
The on-site storm water management system includes area inlets, roof drain piping, trench
drains, parking garage floor drains, sand/oil separator, floor drain sewer ejector pump and
subsurface infiltration galleries. These various components of storm water management
infrastructure are designed to collect, convey, clean, detain, and/or infiltrate storm water runoff
that is generated on the property before it leaves the site or enters local waterways.
Storm water systems require proper maintenance to prevent sediment clogging, overgrown
vegetation, erosion of detention ponds, obstruction of inlets, pipes, and structures, and
prolonged standing water. Such issues may result in downstream pollution, unpleasant odors,
unsightly areas, nuisance insects, or algae blooms, and must be mitigated. Scheduled
inspections, times of inspections, locations inspected, maintenance completed, corrective
actions taken, and any modifications or reconstruction performed shall be documented in the
maintenance logs to be readily available upon request. Disposal of accumulated sediment must
be in accordance with all applicable local, state and federal regulations.
STORM WATER MAINTENANCE PROCEDURES
The following maintenance procedures are intended to prolong the life of installed system
components and ensure their continued functionality:
General Storm Water System Maintenance –
1. Rooftop landscaping/drains, parking garage surfaces/drains, drainage chases, and area
drains should be cleared of leaves and other debris once after primary leaf drop in the
fall and once after snow melt in early spring at a minimum. This will minimize the
potential for debris to enter the system which could lead to premature clogging of
structures, reduced storage capacity, and/or blockage of inlets.
811 West Mendenhall Apartments Storm Water Maintenance Plan
B23-026 2
2. Inspect the roof and floor drain inlets, site storm drain inlets, manholes, cleanouts, and
subsurface chambers for sediment build-up or clogging twice per year, once after
primary leaf drop in the fall and once after snow melt in early spring at a minimum.
Flush/ and clear inlets, structures, and sumps as needed. Inspect for snow/ice buildup at
least once weekly during winter months and clear the inlet as needed. Do not pile snow
over inlets.
3. Snow storage for site and for rooftop amenity areas should be performed in designated
areas during winter months and should not be allowed to be piled in front of or over
drains or inlets. Piled snow around or over the inlets could block early snowmelt run-off
from entering the system, possibly causing overflows and icy conditions.
4. Sanding of the parking garage entries and drive aisles should be done sparingly or
avoided completely. Sand or other sediment tracked into the parking garage structure
will likely be washed into the floor drain system components which can lead to buildup
and reduced capacity or blockages over time.
Sand/Oil Separator Maintenance:
1. The sand/oil separator should be cleaned at least every 90 days or when accumulated
solids reach 25% of the sand/oil separator’s capacity. The waste hauler must identify the
disposal facility on the record of cleaning document.
2. Manhole covers should be checked regularly to ensure they are properly seated and
secure.
3. Check the sanitary tees on the inlet and outlet for damage or clogging. Replace or clean
as needed.
4. Check the sewer ejector pump for buildup and clean as necessary.
Make necessary repairs or replacements if damages or missing components are observed
during regular inspections.
Subsurface Infiltration Gallery (StormTech system) Maintenance:
The subsurface infiltration systems are designed with isolator rows that capture the “first flush”
of pollutants from runoff events. The isolator rows are equipped with inspection ports and direct
manhole access for maintenance. The isolator rows should be inspected for sediment buildup
once every 6-months during the first year of operation, and once a year after that. Use the
general preventative measures described above to help reduce sediment build up and clogging.
Clean out sediment buildup as necessary following the attached manufacturer recommended
procedures.
APPENDIX
Sample Maintenance & Inspection Log
StormTech Isolator Row O&M Manual
Storm Water Facilities Inspection and Maintenance Log
Facility Name
Begin Date End Date
Date Location Facility Description Inspected
by:
Cause for
Inspection
Exceptions Noted Comments and
Actions Taken
Instructions: Record all inspections and maintenance for all storm water facilities on this form. Use additional log sheets and/or
attach extended comments or documentation as necessary. Save all completed logs in one place and have them readily available for
the City of Bozeman’s review upon request.
Location — Specify the exact location of the facility either by its name, facility ID or physical location.
Inspected by — Note all inspections and maintenance on this form, including the required independent annual inspection.
Cause for inspection — Note if the inspection is routine, pre-rainy-season, post-storm, annual, or in response to a noted
problem or complaint.
Exceptions noted — Note any condition that requires correction or indicates a need for maintenance.
Comments and actions taken — Describe any maintenance performed and need for follow-up.
FIGURE 1FIGURE 1
FIGURE 6
An company
2
THE MOST ADVANCED NAME IN WATER MANAGEMENT SOLUTIONS TM
ECCENTRICHEADER
MANHOLEWITHOVERFLOWWEIR
STORMTECHISOLATOR ROW
OPTIONAL PRE-TREATMENT
OPTIONAL ACCESS STORMTECH CHAMBERS
)(
StormTech Maintenance Log
Project Name:
Location:
Stadia Rod Readings
Date Fixed point to chamber
bottom (1)
Fixed point to top of
sediment (2)
Sediment Depth
(1) - (2)Observations / Actions Inspector