HomeMy WebLinkAbout007 APPENDIX C
JOB NO. B21-055
MONTANA | WASHINGTON | IDAHO | NORTH DAKOTA | PENNSYLVANIA
DECEMBER 2021
406.586.0277
tdhengineering.com
234 East Babcock Street
Suite 3
Bozeman, MT 59715
CLIENT ENGINEER
Intrinsik Architecture
106 E. Babcock Street, Suite 1A
Bozeman, MT 59715
TD&H Engineering
234 East Babcock Street, Suite 3
Bozeman, MT 59715
ON-SITE STORM WATER MAINTENANCE PLAN
ANE 9TEN MIXED -USE
BOZEMAN, MONTANA
ANE 9TEN MIXED-USE Storm Water Maintenance Plan
B21-055 1
ANE 9TEN MIXED-USE
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 ANE 9TEN
Mixed-Use project in Bozeman, Montana. For the purpose of this plan, the on-site storm water
management system includes stormwater conveyance paths and pipes within the property, the
subsurface retention chambers and dry well within the parking lot, and the subsurface retention
chambers, dry well, and area inlet within the alley north of the site.
The maintenance responsibility for the on-site stormwater management system belongs to 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 curb and gutter, curb inlets, area inlets,
drainage chases, roof drain piping, trench drains, dry wells, 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.
Wetlands are not anticipated to be encountered during maintenance activities for the on-site
subsurface infiltration facilities. However, maintenance of off-site locations where outlet pipes or
overflows discharge to protected water bodies within wetland areas may require wetland or
stream bank permitting. If unsure of the regulatory status of wetland features observed at the
site, consult the local authorities prior to undertaking any activities that may cause disturbance.
STORM WATER MAINTENANCE PROCEDURES
The following maintenance procedures are intended to prolong the life of installed system
components and ensure their continued functionality:
ANE 9TEN MIXED-USE Storm Water Maintenance Plan
B21-055 2
General Storm Water System Maintenance –
1. Parking lot areas, curbs & gutters, 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.
2. Inspect the storm drain inlets, manholes, and cleanouts, for sediment build-up or
clogging and flush/clear 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 should be performed in designated areas during winter months and
should not be allowed to be piled in front of or over 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 lots and drive aisles should be done sparingly or avoided
completely. Sand or other sediment on the parking lot will likely be washed into
stormwater system components which can lead to buildup and reduced capacity or
blockages over time.
Drywell Maintenance –
1. The grate cover should be visually inspected on a weekly basis for debris or ice buildup.
All ice and debris (leaves, mud, etc.) should be removed to allow water to enter the
drywell.
2. The grate cover should be removed quarterly to inspect the drywell for sediment buildup.
If there is standing water inside the drywell due to sediment buildup, the drywell should
be vacuumed clean. Upon vacuuming, if water continues to pond in the drywell after
storm events for more than 48 hours, the soil surrounding the drywell may be
contaminated and should be examined by a professional familiar with drywell
construction.
3. The drywells should be vacuumed, at a minimum, every 3-5 years.
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 row 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