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Indianapolis, IN | St. Louis, MO | .www.weihe.net | (800) 452-6408
Allan H. Weihe, P.E., L.S. - Founder
Post-Construction Stormwater Quality BMP
Operations and Maintenance Manual
For:
Rosie’s Gardens
Address:
10402 N. College Ave, Carmel, IN 46280
Project # W220156
Prepared For:
Rosie’s Gardens
10402 N. College Ave, Carmel, IN 46280
Phone: (317) 844-6157
Contact: Kevin Hughes
Prepared By: Steven S. Rucker, P.E.
Date:
May 17, 2023
Revised:
August 17, 2023
I AFFIRM, UNDER THE PENALTIES FOR PERJURY, THAT I HAVE TAKEN REASONABLE
CARE TO REDACT EACH SOCIAL SECURITY NUMBER IN THIS DOCUMENT, UNLESS
REQUIRED BY LAW. – Steven S Rucker
THIS INSTRUMENT PREPARED BY: Steven S Rucker
1 of 34
Operation and Maintenance Manual
Rosie’s Gardens
Carmel, IN
Project #W220156
TABLE OF CONTENTS
Operation and Maintenance Manual
1. Project Narrative
2. Definitions
3. Owner Acknowledgement
4. Location Maps
5. Pond Protection Sign Details
6. Pond Cross-section
7. Checklists and Maintenance Activities
8. Hydro International First Defense Specific Maintenance and Checklists
2 of 34
Project Narrative
Rosie’s Gardens is proposing to redevelop a portion of their property to remove current
facilities and construct a new commercial building with parking and stormwater facilities.
The property is located at 10402 N College Ave, Carmel, IN 46280. Currently the project
site is utilized for a commercial building, parking, and outdoor commercial sales for
gardening and landscaping supplies.
The proposed construction is on a site at a Latitude of 39° 56’ 17” N and Longitude of
86° 08’ 46” W, falling within Clay Township. The site is part of Section 11, Township 17
North, Range 3 East, Hamilton County, Indiana. Please refer to Figure 1.1.
The development will use a combination of a hydrodynamic separator and a dry pond
with native plantings to achieve the required stormwater treatment.
Refer to Figure 3.1 for the location of the following BMP features for said
development:
• Mechanical (Hydrodynamic) Stormwater Quality Unit (SQU or BMP)
• Dry Pond BMP
BMP Owner Contact Information:
Rosie’s Gardens
10402 N. College Ave
Carmel, IN 46280
Phone: (317) 844-6157
Contact: Kevin Hughes
3 of 34
Definitions
Best Management Practice (BMP):
Best Management Practices, refer to structural or non-structural measures designed for
the benefit of water quality and quantity.
Urban stormwater runoff may contain many types and forms of pollutants. When
compared to stormwater run-off from pre-development conditions, high concentrations
and some contaminants that are not naturally present in surface runoff from
undeveloped local lands are found in urban stormwater runoff. Runoff from
undeveloped watersheds contains metals, nutrients, sediment particles, oxygen-
demanding compounds, and other constituents. Constituent loads increase on developed
lands because of increases in surface runoff volumes and the sources of many of these
pollutants. Supplemental applications of compounds, such as fertilizers, also tend to
increase the presence of some pollutants in stormwater runoff.
Runoff water quality in urban areas can be detrimental to local habitat. Paved surfaces
and standing water bodies for stormwater management control elevate the temperature
of water entering streams. Chemicals in standing water and ponds are oxidized,
resulting in depressed levels of dissolved oxygen. Increased runoff volumes and rates
create scour and deposition damage to instream habitat. Activities in urbanized areas,
such as vehicular traffic, deposit pollutants such as heavy metals and oil and grease on
paved surfaces where they can wash off into the streams.
BMP Owner:
The owner of the BMP is typically the property owner. The BMP owner may also be the
lessee of the property in the case of long-term leases of commercial and industrial zoned
properties.
Dry Detention Basin with Native Plantings:
A Dry Detention Pond is a facility, which removes sediment, total suspended solids
(TSS), biochemical oxygen demand (BOD), organic nutrients, and trace metals from
stormwater runoff. This is accomplished by slowing down stormwater using an in-line
temporary pool or pond affection settling pollutants. The dry pond is similar to a wet
pond, except that no permanent volume of water is incorporated into the design. The dry
pond will incorporate a blend of native plantings for ground cover within the pond limits.
The plants selected for this specific seed mix are well suited for wet areas and water
ways. They have deep roots that result in added capacity to absorb and filter runoff water.
They can also thrive without extra fertilizers, pesticides, and watering. A list of plantings
and a maintenance guide are included with this manual.
Visual inspections should be made on a routine basis. It is recommended that inspections
be performed bi-annually and after major storm events. Trash, brush, and other debris
4 of 34
should be removed regularly. Visible erosion and scour along water flow line, riprap
areas, and adjacent to end sections should be re-dressed. Displaced riprap should be
restored to its original condition, and if necessary, new riprap should be installed.
Mechanical Stormwater Quality Unit (SQU):
The mechanical stormwater quality unit (or hydrodynamic separator) provides a highly
effective means for the removal of sediment, floating debris and free-oil. Swirl
technology, or vortex separation, is a proven form of treatment utilized in the
stormwater industry to accelerate gravitational separation. The SQU provides treatment
for most contaminated first flush, while the cleaner peak storm flow is diverted and
channeled through the main conveyance pipe. A combination of gravitational and
hydrodynamic drag forces causes the solids to drop out of the flow and migrate to the
center of the chamber where velocities are the lowest.
General Maintenance notes for SQU’s
• Entry into an SQU is often considered an OSHA confined space entry and
should follow the appropriate guidelines.
• Any water or sediment used in cleaning the SQU should not be dumped
into a sanitary sewer.
• SQU’s should be inspected and cleaned immediately following a
hydrocarbon spill on the property.
• Disposal of sediments removed from the SQU must be in compliance with all
federal, state, and local requirements.
Stormwater Infrastructure:
Storm water infrastructure and structures refers to structural or non-structural measures
designed for the benefit of storm water conveyance. Storm water is the rainfall/
snowmelt that flows over our yards, streets, parking lots, and buildings and either enters
the storm drain system or runs directly into a lake or stream.
Owners of storm water infrastructure and structures are typically the property owners.
The storm water infrastructure owner may also be the lessee of the property in the case
of long-term leases of commercial and industrial zoned properties. The lessee is
considered the owner only if the lease specifically states that construction by the lessee
must meet applicable local codes and regulations.
Catch basins:
Catch basin/inlet cleaning and repair has traditionally been performed to respond to
localized flooding problems in streets. Catch basins are inlets at the curb with a small trap
(usually six inches to one foot deep) below the sewer pipe. These devices help to clean
storm water because particles in street runoff settle into the trap before the water enters
the storm sewers. Catch basins require regular cleaning of the sediment trap. The inlets
do not trap sediments and don’t need cleaning unless they are plugged. Cleaning of either
5 of 34
catch basins or inlets can be done by hand (e.g., with a clamshell or shovel) or with a
vacuum truck.
Conveyance Storm Pipes:
A good rule of thumb is to conduct inspection of storm drain inlets and other drainage
facilities at least once a year, prior to the beginning of the rainy season. Complete
inspections early enough so that repairs can be made during dry weather. Catch
basins/inlets should be inspected at least once every six months. Storm Pipes and culverts
should be inspected every three to five years, or in response to a problem. Most agencies
inspect their sewer pipes six inches or larger with a TV camera. All other parts of the
system are inspected visually.
Look for excessive silt build-up, erosion, unusual algal growth, cracked or collapsed
pipes, misaligned joints, and other signs of problems such as a sheen on the water
surface, discolored water, or an unpleasant odor. Check with product manufacturers or
storm water handbooks for advice on what to look for when inspecting more
sophisticated treatment devices such as flow splitters and diverters. When a problem is
noted, take steps to correct the problem, or route this information immediately to the
appropriate individual(s) in your organization who can respond. If needed, develop a
good response plan to ensure quick follow-up in the future.
Open Channels, End Sections, and Riprap Protection:
Open channels such as swales and ditches convey runoff between reaches of enclosed
drainage systems and culverts. End sections are typically installed to manage energy
changes at upstream and downstream ends of culverts and downstream ends of discharge
pipes. Riprap along channel inverts and end sections also protects ground surfaces from
high flow velocities and turbulence resulting from energy changes.
Visual inspections should be made on a routine basis. Trash, brush, and other debris
should be removed regularly. Visible erosion and scour along swale footprints, riprap
areas, and adjacent to end sections should be re-dressed. Displaced riprap should be
restored to its original condition, and if necessary, new riprap should be installed.
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MIX STATISTICS
NATIVE
COMPONENT
PLS
LBS./ACRE
PLS
SEEDS/ACRE
PLS
SEEDS/SQ.FT.
% OF NATIVE
MIX
FORBS 4.25 1,355,250 31.11 76.43%
GRASSES 2.75 417,831 9.59 23.57%
TOTAL NATIVES 7 1,773,081 40.7 100.00%
COVER 28.75 4,343,800 99.72
TOTALS 35.75 6,116,881 140.42
STORMWATER SEED MIX
BOTANICAL NAME COMMON NAME OZ./ACRE
PERMANENT GRASSES:
SCHIZACHYRIUM SCOPARIUM LITTLE BLUESTEM 36
SORGHASTRUM NUTANS INDIAN GRASS 2
SPOROBOLUS HETEROLEPRIS PRAIRIE DROPSEED 6
TOTAL 44
TEMPORARY COVER:
AVENA SATIVA COMMON OAT 360
LOLIUM MULTIFLORUM ANNUAL RYE 100
TOTAL 460
FORBS:
AGASTACHE FOENICULUM LAVENDER HYSSOP 2
ALLIUM CERNUUM NODDING ONION 2
AMORPHA CANESCENS LEAD PLANT 2
ASCLEPIAS SYRIACA COMMON MILKWEED 10
ASCLEPIAS TUBEROSA BUTTERFLY WEED 2
BAPTISIA BRACTEATA CREAM WILD INDIGO 1
CHAMAECRISTA FASCICULATA PARTRIDGE PEA 8
DALEA CANDIDA WHITE PRAIRIE CLOVER 3
ECHINACEA PALLIDA PURPLE CONEFLOWER 4
ECHINACEA PURPUREA BROAD-LEAVED PURPLE CONEFLOWER 8
ERYNGIUM YUCCIFOLIUM RATTLESNAKE MASTER 2
LIATRIS PYCNOSTACHYA PRAIRIE BLAZING STAR 1
LUPINUS PERENNIS V. OCCIDENTALIS WILD LUPINE 4
MONARDA FISTULOSA WILD BERGAMOT 2
PENSTEMON DIGITALIS FOXGLOVE BEARD TONGUE 1
PENSTEMON HIRSUTUS HAIRY BEARD TONGUE 1
PYCNANTHEMUM VIRGINIANUM COMMON MOUNTAIN MINT 0.5
SENNA HEBECARPA WILD SENNA 4
SILPHIUM PERFOLIATUM CUP PLANT 1
SOLIDAGO SPECIOSA SHOWY GOLDENROD 1
SYMPHYOTRICHUM ERICOIDES HEATH ASTER 0.5
SYMPHYOTRICHUM LAEVE SMOOTH BLUE ASTER 1
TRADESCANTIA OHIENSIS COMMON SPIDERWORT 2
VERBENA STRICTA HOARY VERVAIN 2
VERBESINA ALTERNIFOLIA WINGSTEM 2
VERNONIA GIGANTEA SMOOTH TALL IRONWEED 1
TOTAL 68
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Inspections
Routine inspections are the responsibility of the BMP owner. Maintenance is also the
responsibility of the owner. The BMP owner shall be financially responsible for any
maintenance or repairs required by the City or its representatives. The approval
maintenance plan and inspection forms provided with this manual should be used as
guidance for performing maintenance activities. Completed inspection forms must be
maintained by the BMP owner and produced upon request by the City. The City must be
notified of any changes in BMP ownership, major repairs or BMP failure in writing
within 30 days. The letter should be addressed to:
Stormwater BMP Modifications
Department of Engineering
City of Carmel
One Civic Square
Carmel, IN 46032
The City and/or its representatives have the right to enter the property to inspect BMPs.
In the event that the City finds a BMP in need of maintenance or repair, the City will
notify the BMP owner of the necessary maintenance or repairs and give the landowner a
timeframe for completing the maintenance or repairs. If the maintenance or repairs are
not completed within the designated timeframe, the City shall perform the maintenance
or repairs and bill the landowner for the actual costs for the work.
BMP Inspection Schedule
1. All BMPs will be inspected annually by the owner at a minimum.
2. The Underground Detention System will be inspected by the owner per the
Operation, Maintenance, and Management Inspection Checklists.
3. Storm structures will be inspected by the owner quarterly and after every major
rainfall event.
4. SQUs will be inspected annually by the owner per provided guidelines and after
every major rainfall event.
5. SQUs will be inspected and cleaned immediately if there is a gasoline or oil spill.
Inspection & Maintenance Activities
Refer to the checklist provided with this manual for operation, maintenance and
inspection of BMP and storm water infrastructure. The checklist is for the use of the
BMP owner in performing routine inspections. The BMP owner must maintain and
8 of 34
update the BMP operations and maintenance plan as conditions change. At a minimum,
the operations and maintenance plan must include, but is not limited to:
1. Visual inspect and removal of debris from storm sewers and structures
2. Removal of woody vegetation from swales and other drainageways
BMP owners must routinely inspect BMPs to verify that all BMP components are
functioning as designed and are not in danger of failing. All BMPs need maintenance to
function as water quality and quantity enhancements. Storm sewer should be kept clear of
sediments and debris. The natural areas near inlets and outlets associated with the storm
sewer system should be repaired when needed to avoid introducing soil and sediment to
this system or downstream systems.
The BMP owner agrees to the maintenance and inspection programs attached with this
manual. Inspections must be documented on the inspection forms included in this
Operation and Maintenance Manual.
A self-monitoring program by the project site owner is required during construction. A
trained individual employed or retained by the project site owner shall prepare and
maintain a written evaluation of the project site by the end of the next business day
following each measurable rainfall.
Inspection during construction should be after a storm event and at a minimum, one (1)
time a week. Inspections during the post-construction operation and maintenance period
must include routine inspection of all storm water infrastructure to verify that all
components are functioning as designed and are not in danger of failing. The stormwater
system shall be inspected on an annual basis or upon observed failure.
Note that entry into the SQUs should be considered confined space and inspection
and maintenance activities should be performed in compliance with OSHA
guidelines, see Section 6 of the O&M manual.
Note also that all sediments and oil absorbent material shall be disposed of in
accordance with all federal requirements and NOT dumped into the storm or
sanitary sewer systems.
9 of 34
Owner Acknowledgement Agreement (“Agreement”)
For good and valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the undersigned owner (“Owner”) hereby submits this Operation and
Maintenance Manual (“Manual”) to the City of Carmel, Indiana (“City”) as a written
acknowledgement of Owner’s warranty and agreement to institute, maintain, and follow
the water quality Best Management Practices (“BMPs”) listed below, and to follow and
abide by the inspection schedule and maintenance activities listed in this Manual. The
Owner also hereby agrees to provide, at Owner’s cost, all additional maintenance, repair,
and/or replacement services reasonably necessary to maintain the function and longevity
of the BMPs from and including the date this Agreement is executed by Owner to and
including the date on which a new Agreement is filed with the City by another party who
assumes all of the obligations and responsibilities of Owner as set forth herein.
BMPs: Hydro International First Defense 5-ft_____________________
Dry Detention with Native Vegetation BMP
__________________
_______________________________ _______________________________
Owner Signature Date
_______________________________ _______________________________
Printed Name Company
STATE OF INDIANA )
) SS:
COUNTY OF HAMILTON )
BEFORE ME, the undersigned, a Notary Public in and for said County and State,
personally appeared _________________________________ Owner subscribed and
sworn before this ____ day of __________________, ________.
_______________________________ _______________________________
County of Residence Signature
______________________________
Commission Expiration Date
______________________________
Printed Name
10 of 34
FIGURE 1.1
WEIHE weihe.net
Indianapolis, Indiana 46280
10505 N. College Avenue
317 | 846 - 6611E N G I N E E R S
W
S
N
E
LOCATION MAPROSIE'S GARDENS
05-12-2023
E 106th St
N Pennsylvania StN College AveUS 31 / Meridian StI-465
103rd St
PROJECT LOCATION
NO SCALE
11 of 34
E E E
PROPOSED BMP LOCATIONS
FIGURE 3.1
WEIHE weihe.net
Indianapolis, Indiana 46280
10505 N. College Avenue
317 | 846 - 6611E N G I N E E R S
W
S
N
E
08-17-2023
ROSIE'S GARDENS
LIMITS OF
WQ VOLUME
EMERGENCY SPILLWAY
BYPASS STRUCTURE
HYDRO INTERNATIONAL
FIRST DEFENSE UNIT
BMP EASEMENT
BMP EASEMENT
DRY POND BMP TOP OF BANK
AND LIMIT OF NATIVE SEED MIX
OUTLET CONTROL STRUCTURE
BMP EASEMENT
POND PROTECTION SIGN
12 of 34
ROSIE'S GARDENS
08-17-2023
FIGURE 3.4
WEIHE weihe.net
Indianapolis, Indiana 46280
10505 N. College Avenue
317 | 846 - 6611E N G I N E E R S
POND PROTECTION
SIGN DETAILS
13 of 34
ROSIE'S GARDENS
08-17-2023
FIGURE 3.5
WEIHE weihe.net
Indianapolis, Indiana 46280
10505 N. College Avenue
317 | 846 - 6611E N G I N E E R S
POND PROTECTION
SIGN DETAILS
WOOD POND SAFTEY BARRIER
(NO SCALE)
14" DIA. CONCRETE FOOTING
SEALANT
SLOPE TO DRAIN
PROPOSED GRADE
6"X6" WOOD POST
MITER TOP OF POST
4" TYP.4"3'-6"4'-0"CAUTION: POND AREA
·MOW ONLY 3 TIMES/YEAR:
LATE SPRING, MID SUMMER, EARLY FALL
·MOW NO SHORTER THAN 8"
·DO NOT MOW IN WET OR MUDDY LOCATIONS
POND PROTECTION SIGN
(NO SCALE)
14 of 34
ROSIE'S GARDENS
08-17-2023
FIGURE 3.6
WEIHE weihe.net
Indianapolis, Indiana 46280
10505 N. College Avenue
317 | 846 - 6611E N G I N E E R S
POND CROSS-SECTION
15 of 34
PLAN VIEW
SECTION A-A
PARTS LIST
DESCRIPTIONSIZE (mm)SIZE (in)QTYITEM
I.D. PRECAST MANHOLE15006011
INTERNAL COMPONENTS
(PRE-INSTALLED)
12
FRAME AND COVER (ROUND)7503013
OUTLET PIPE (BY OTHERS)600 (MAX)24 (MAX)14
INLET PIPE (BY OTHERS)600 (MAX)24 (MAX)15
A A
WEIGHT:
SHEET SIZE:
B
SHEET :
1 OF 1
DRAWING NO.:
FD GA-5
STOCK NUMBER:
hydro-int.com
HYDRO INTERNATIONAL
Rev:
-
Title
5-ft DIAMETER
FIRST DEFENSE
DRAWN BY:
ER
CHECKED BY:
MRJ
APPROVED BY
DATE:
11/2/2021
SCALE:
1:30
PROJECTION
MATERIAL:
GENERAL ARRANGEMENT
IF IN DOUBT ASK
5
1. MANHOLE WAL L AND SLAB
THICKNESSES ARE NOT TO
SCALE.
2. CONTACT HYDRO
INTERNATIONAL FOR A BOTTOM
OF STRUCTURE ELEVATION
PRIOR TO SETTING FIRST
DEFENSE MANHOLE.
3. CONTRACTOR TO CONFIRM
RIM, PIPE INVERTS, PIPE DIA.
AND PIPE ORIENTATION PRIOR
TO RELEASE OF UNIT TO
FABRICATION.
PRODUCT SPECIFICATION:
1. Peak Hydraulic Flow: 20.0 cfs (566 l/s)
2. Min Sediment Storage Capacity: 1.1 cu. yd. (0.8 cu. m.)
3. Maximum Inlet/Outlet Pipe Diameters: 24 in. (600 mm)
4. The treatment system shall use an induced vortex to separate pollutants from stormwater runoff.
5. For more product information including regulatory acceptances, please visit
https://hydro-int.com/en/products/first-defense
GENERAL NOTES:
1. General Arrangement drawings only. Contact Hydro International for site specific drawings.
2. The diameter of the inlet and outlet pipes may be no more than 24".
3. Multiple inlet pipes possible (refer to project plan).
4. Inlet/outlet pipe angle can vary to align with drainage network (refer to project plans).
5. Peak flow rate and minimum height limited by available cover and pipe diameter.
6. Larger sediment storage capacity may be provided with a deeper sump depth.
4
1
1
3
4
2.40 ft [.730 m]BOTTOM OF INTERNALS:
3.90 ft [1.187 m]PREASSEMBLY REFERENCE:
5.83 ft [1.777 m]PIPE INVERTS: (MINIMUM)
9.33 ft [2.844 m]T.O.S: (MINIMUM)
RIM: VARIES
.00 ft [.000 m]SUMP:
5
2
NOTE: ADDITIONAL HEIGHT MAY BE
REQUIRED DEPENDING ON PIPE SIZE
HYDRO FRAME AND
COVER (INCLUDED)
GRADE RINGS BY OTHERS
AS REQUIRED
16 of 34
Operation and Maintenance Manual
First Defense® High Capacity and First Defense®Optimum
Vortex Separator for Stormwater Treatment
17 of 34
First Defense® Operation and Maintenance Manual
Hydro International (Stormwater), 94 Hutchins Drive, Portland ME 04102
Tel: (207) 756-6200 Fax: (207) 756-6212 Web: www.hydro-int.com
Table of Contents
3 First Defense® by Hydro International
- Introduction
- Operation
- Pollutant Capture and Retention
4 Model Sizes & Configurations
- First Defense® Components
5 Maintenance
- Overview
- Maintenance Equipment Considerations
- Determining Your Maintenance Schedule
6 Maintenance Procedures
- Inspection
- Floatables and Sediment Clean Out
8 First Defense® Installation Log
9 First Defense® Inspection and Maintenance Log
COPYRIGHT STATEMENT: The contents of this manual, including the graphics contained herein, are intended for the use of the recipient to whom the
document and all associated information are directed. Hydro International plc owns the copyright of this document, which is supplied in confidence. It
must not be used for any purpose other than that for which it is supplied and must not be reproduced, in whole or in part stored in a retrieval system or
transmitted in any form or by any means without prior permission in writing from Hydro International plc. First Defense® is a trademarked hydrodynamic
vortex separation device of Hydro International plc. A patent covering the First Defense® has been granted.
DISCLAIMER: Information and data contained in this manual is exclusively for the purpose of assisting in the operation and maintenance of Hydro
International plc’s First Defense®. No warranty is given nor can liability be accepted for use of this information for any other purpose. Hydro International
plc has a policy of continuous product development and reserves the right to amend specifications without notice.
Page | 2
18 of 34
First Defense® Operation and Maintenance Manual
I. First Defense® by Hydro International
Page | 3
Introduction
The First Defense® is an enhanced vortex separator that
combines an effective and economical stormwater treatment
chamber with an integral peak flow bypass. It efficiently removes
total suspended solids (TSS), trash and hydrocarbons from
stormwater runoff without washing out previously captured
pollutants. The First Defense® is available in several model
configurations to accommodate a wide range of pipe sizes,
peak flows and depth constraints.
The two product models described in this guide are the First
Defense® High Capacity and the First Defense® Optimum;
they are inspected and maintained identically.
Operation
The First Defense® operates on simple fluid hydraulics. It is self-
activating, has no moving parts, no external power requirement
and is fabricated with durable non-corrosive components.
No manual procedures are required to operate the unit and
maintenance is limited to monitoring accumulations of stored
pollutants and periodic clean-outs. The First Defense® has
been designed to allow for easy and safe access for inspection,
monitoring and clean-out procedures. Neither entry into the
unit nor removal of the internal components is necessary for
maintenance, thus safety concerns related to confined-space-
entry are avoided.
Pollutant Capture and Retention
The internal components of the First Defense® have been
designed to optimize pollutant capture. Sediment is captured
and retained in the base of the unit, while oil and floatables
are stored on the water surface in the inner volume (Fig.1).
The pollutant storage volumes are isolated from the built-in
bypass chamber to prevent washout during high-flow storm
events. The sump of the First Defense® retains a standing
water level between storm events. This ensures a quiescent
flow regime at the onset of a storm, preventing resuspension
and washout of pollutants captured during previous events.
Accessories such as oil absorbent pads are available for
enhanced oil removal and storage. Due to the separation
of the oil and floatable storage volume from the outlet, the
potential for washout of stored pollutants between clean-outs
is minimized.
• Inlet options include surface grate or multiple inlet pipes
• Integral high capacity bypass conveys large peak flows without
the need for “offline” arrangements using separate junction
manholes
• Long flow path through the device ensures a long residence
time within the treatment chamber, enhancing pollutant settling
• Delivered to site pre-assembled and ready for installation
Advantages
• Stormwater treatment at the point of entry into the drainage line
• Sites constrained by space, topography or drainage profiles
with limited slope and depth of cover
• Retrofit installations where stormwater treatment is placed on or
tied into an existing storm drain line
• Pretreatment for filters, infiltration and storage
Applications
Oil Max Oil
Storage Depth
Sediment
StorageSediment
Fig.1 Pollutant storage volumes in the First Defense®.
19 of 34
First Defense® Operation and Maintenance Manual
Hydro International (Stormwater), 94 Hutchins Drive, Portland ME 04102
Tel: (207) 756-6200 Fax: (207) 756-6212 Web: www.hydro-int.com
7
II. Model Sizes & Configurations
The First Defense® inlet and internal bypass arrangements are available in several model sizes and configurations. The components
have modified geometries allowing greater design flexibility to accommodate various site constraints.
Page | 4
First Defense® Components
1. Built-In Bypass
2. Inlet Pipe
3. Inlet Chute
4. Floatables Draw-off Port
5. Outlet Pipe
6. Floatables Storage
12
3
4
5
6
7
8
(not pictured)
All First Defense® models include the internal components that are designed to remove and retain total suspended solids (TSS),
gross solids, floatable trash and hydrocarbons (Fig.2). First Defense® model sizes (diameter) are shown in Table 1.
III. Maintenance
7. Sediment Storage
8. Inlet Grate or Cover
First Defense®
Model Sizes
(ft / m) diameter
3 / 0.9
4 / 1.2
5 / 1.5
6 / 1.8
7 / 2.1
8 / 2.4
10 / 3.0
Fig. 2
Table 1
20 of 34
First Defense® Operation and Maintenance ManualPage | 5
Overview
The First Defense® protects the environment by removing a wide range of pollutants from stormwater runoff. Periodic removal of
these captured pollutants is essential to the continuous, long-term functioning of the First Defense®. The First Defense® will capture
and retain sediment and oil until the sediment and oil storage volumes are full to capacity. When sediment and oil storage capacities
are reached, the First Defense® will no longer be able to store removed sediment and oil.
The First Defense® allows for easy and safe inspection, monitoring and clean-out procedures. A commercially or municipally owned
sump-vac is used to remove captured sediment and floatables. Access ports are located in the top of the manhole.
Maintenance events may include Inspection, Oil & Floatables Removal, and Sediment Removal. Maintenance events do not require
entry into the First Defense®, nor do they require the internal components of the First Defense® to be removed. In the case of
inspection and floatables removal, a vactor truck is not required. However, a vactor truck is required if the maintenance event is to
include oil removal and/or sediment removal.
Maintenance Equipment Considerations
The internal components of the First Defense® have a centrally located circular shaft through which the sediment storage sump can
be accessed with a sump vac hose. The open diameter of this access shaft is 15 inches in diameter (Fig.3). Therefore, the nozzle
fitting of any vactor hose used for maintenance should be less than 15 inches in diameter.
Determining Your Maintenance Schedule
The frequency of clean out is determined in the field after installation. During the first year of operation, the unit should be inspected
every six months to determine the rate of sediment and floatables accumulation. A simple probe such as a Sludge-Judge® can be
used to determine the level of accumulated solids stored in the sump. This information can be recorded in the maintenance log (see
page 9) to establish a routine maintenance schedule.
The vactor procedure, including both sediment and oil / flotables removal, for First Defense® typically takes less than 30 minutes and
removes a combined water/oil volume of about 765 gallons.
Fig.3 The central opening to the sump of the First Defense®is 15 inches in diameter.
15-in Maintenance Access
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First Defense® Operation and Maintenance Manual
Hydro International (Stormwater), 94 Hutchins Drive, Portland ME 04102
Tel: (207) 756-6200 Fax: (207) 756-6212 Web: www.hydro-int.com
Inspection Procedures
1. Set up any necessary safety equipment around the access
port or grate of the First Defense® as stipulated by
local ordinances. Safety equipment should notify passing
pedestrian and road traffic that work is being done.
2. Remove the grate or lid to the manhole.
3. Without entering the vessel, look down into the chamber to
inspect the inside. Make note of any irregularities. Fig.4
shows the standing water level that should be observed.
4. Without entering the vessel, use the pole with the skimmer net
to remove floatables and loose debris from the components
and water surface.
5. Using a sediment probe such as a Sludge Judge®, measure
the depth of sediment that has collected in the sump of the
vessel.
6. On the Maintenance Log (see page 9), record the date, unit
location, estimated volume of floatables and gross debris
removed, and the depth of sediment measured. Also note
any apparent irregularities such as damaged components or
blockages.
7. Securely replace the grate or lid.
8. Take down safety equipment.
9. Notify Hydro International of any irregularities noted during
inspection.
Floatables and Sediment Clean Out
Floatables clean out is typically done in conjunction with
sediment removal. A commercially or municipally owned sump-
vac is used to remove captured sediment and floatables (Fig.4).
Floatables and loose debris can also be netted with a skimmer
and pole. The access port located at the top of the manhole
provides unobstructed access for a vactor hose to be lowered to
the base of the sump.
Scheduling
• Floatables and sump clean out are typically conducted once
a year during any season.
• Floatables and sump clean out should occur as soon as
possible following a spill in the contributing drainage area.
Recommended Equipment
• Safety Equipment (traffic cones, etc)
• Crow bar or other tool to remove grate or lid
• Pole with skimmer or net (if only floatables are being removed)
• Sediment probe (such as a Sludge Judge®)
• Vactor truck (flexible hose recommended)
• First Defense® Maintenance Log
Fig.4 Floatables are removed with a vactor hose
Page | 6
22 of 34
First Defense® Operation and Maintenance Manual
Floatables and Sediment Clean Out Procedures
1. Set up any necessary safety equipment around the access
port or grate of the First Defense® as stipulated by
local ordinances. Safety equipment should notify passing
pedestrian and road traffic that work is being done.
2. Remove the grate or lid to the manhole.
3. Without entering the vessel, look down into the chamber to
inspect the inside. Make note of any irregularities.
4. Remove oil and floatables stored on the surface of the water
with the vactor hose or with the skimmer or net
5. Using a sediment probe such as a Sludge Judge®, measure
the depth of sediment that has collected in the sump of the
vessel and record it in the Maintenance Log (page 9).
6. Once all floatables have been removed, drop the vactor hose
to the base of the sump. Vactor out the sediment and gross
debris off the sump floor
7. Retract the vactor hose from the vessel.
8. On the Maintenance Log provided by Hydro International,
record the date, unit location, estimated volume of floatables
and gross debris removed, and the depth of sediment
measured. Also note any apparent irregularities such as
damaged components, blockages, or irregularly high or low
water levels.
9. Securely replace the grate or lid.
- Regularly during first year of installation
- Every 6 months after the first year of installation
- Once per year, with sediment removal
- Following a spill in the drainage area
- Once per year or as needed
- Following a spill in the drainage area
Activity FrequencyInspection
Oil and Floatables
Removal
Sediment Removal
Maintenance at a Glance
NOTE: For most clean outs the entire volume of liquid does not need to be removed from the manhole. Only remove the
first few inches of oils and floatables from the water surface to reduce the total volume of liquid removed during a clean out.
Page | 7
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First Defense® Installation Log
HYDRO INTERNATIONAL REFERENCE NUMBER:
SITE NAME:
SITE LOCATION:
OWNER: CONTRACTOR:
CONTACT NAME: CONTACT NAME:
COMPANY NAME: COMPANY NAME:
ADDRESS: ADDRESS:
TELEPHONE: TELEPHONE:
FAX: FAX:
INSTALLATION DATE: / /
MODEL SIZE (CIRCLE ONE): [3-FT] [4-FT] [5-FT] [6-FT] [7-FT] [8-FT] [10-FT]
INLET (CIRCLE ALL THAT APPLY): GRATED INLET (CATCH BASIN) INLET PIPE (FLOW THROUGH)
Hydro International (Stormwater), 94 Hutchins Drive, Portland ME 04102
Tel: (207) 756-6200 Fax: (207) 756-6212 Web: www.hydro-int.com
24 of 34
First Defense® Inspection and Maintenance Log
Initials Depth of
Floatables
and Oils
Sediment
Depth
Measured
Volume of
Sediment
Removed
Site Activity and
Comments
Date
Hydro International (Stormwater), 94 Hutchins Drive, Portland ME 04102
Tel: (207) 756-6200 Fax: (207) 756-6212 Web: www.hydro-int.com Hydro International (Stormwater), 94 Hutchins Drive, Portland ME 04102
Tel: (207) 756-6200 Fax: (207) 756-6212 Web: www.hydro-int.com
25 of 34
First Defense® Operation and Maintenance Manual
Hydro International (Stormwater), 94 Hutchins Drive, Portland ME 04102
Tel: (207) 756-6200 Fax: (207) 756-6212 Web: www.hydro-int.com
NOTES
26 of 34
First Defense® Operation and Maintenance ManualNotes
27 of 34
Stormwater Solutions
94 Hutchins Drive
Portland, ME 04102
Tel: (207) 756-6200
Fax: (207) 756-6212
stormwaterinquiry@hydro-int.com
www.hydro-int.com
Turning Water Around...®
FD_O+M_K_2105
28 of 34
Site Name:
Owner Name:
Owner Address:
Owner Phone Number:
Emergency Phone Number:
Location:
Date:
Time:
Inspector:
Change in ownership since last
inspection?
Maintenance Item Maintenance (1 or 2)*Maintenance is needed:Comments
Trash or debris which is located immediately in front of the catch
basin opening or is blocking inletting capacity of the basin by more
than 10%
Trash or debris (in the basin) that exceeds 60 percent of the sump
depth as measured from the bottom of basin to invert of the lowest
pipe into or out of the basin, but in no case less than a minimum of
six inches clearance from the debris surface to the invert of the
lowest pipe.
Trash or debris in any inlet or outlet pipe blocking more than 1/3 of
its height.
Dead animals or vegetation that could generate odors that could
cause complaints or dangerous gases (e.g., methane).
Sediment Sediment (in the basin) that exceeds 60 percent of the sump depth as
measured from the bottom of basin to invert of the lowest pipe into
or out of the basin, but in no case less than a minimum of 6 inches
clearance from the sediment surface to the invert of the lowest pipe.
Top slab has holes larger than 2 square inches or cracks wider than
1/4 inch (Intent is to make sure no material is running into basin).
Frame not sitting flush on top slab, i.e., separation of more than 3/4
inch of the frame from the top slab. Frame not securely attached
Maintenance person judges that structure is unsound.
Grout fillet has separated or cracked wider than 1/2 inch and longer
than 1 foot at the joint of any inlet/outlet pipe or any evidence of soil
particles entering catch basin through cracks.
Settlement/Misalignment
If failure of basin has created a safety, function, or design problem.
Vegetation growing across and blocking more than 10% of the basin
opening.
Vegetation growing in inlet/outlet pipe joints that is more than six
inches tall and less than six inches apart.
Contaminants and Pollution Any evidence of oil, gasoline, contaminants or other pollutants
(Coordinate removal/cleanup with local water quality response
agency).
Cover is missing or only partially in place. Any open catch basin
requires maintenance.
Mechanism cannot be opened by one maintenance person with
proper tools. Bolts into frame have less than 1/2 inch of thread.
One maintenance person cannot remove lid after applying normal
lifting pressure (Intent is to keep cover from sealing off access to
maintenance).
Ladder Ladder is unsafe due to missing rungs, not securely attached to basin
wall, misalignment, rust, cracks, or sharp edges.
Metal Grates Trash and debris that is blocking more than 20% of grate surface
inletting capacity.
*Maintenance: Enter 1 if maintenance is need and include WO#. Enter 2 if maintenance was performed same day.
Inspection and Maintenance Checklist
Catch Basins, Manholes, and Inlets
Vegetation
Catch Basin Cover
Fractures or Cracks in Basin
Walls/Bottom
Structure Damage to Frame and/or
Top Slab
Trash & Debris
Y OR N
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Site Name:
Owner Name:
Owner Address:
Owner Phone Number:
Emergency Phone Number:
Location:
Date:
Time:
Inspector:
Change in ownership since
last inspection?
Maintenance Item Maintenance (1 or 2)*Maintenance is needed:Comments
Sediment & Debris Accumulated sediment exceeds buildup 1/4" of the
pipe diameter up to maximum of 6"
Vegetation Vegetation that reduces free movement of water
through the pipes
Protective coating is damaged; rust is causing more
than 50% deterioration to any part of the pipe
Any dent that decreases the cross section area of pipe
by more than 20% or puncture that impacts
performance
*Maintenance: Enter 1 if maintenance is need and include WO#. Enter 2 if maintenance was performed same day.
Inspection and Maintenance Checklist
Y OR N
Damaged Pipe
Conveyance Stormwater Pipe
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Site Name:
Owner Name:
Owner Address:
Owner Phone Number:
Emergency Phone Number:
Location:
Date:
Time:
Inspector:
Change in ownership since last
inspection?
Maintenance Item Maintenance (1 or 2)*Maintenance is needed:Comments
Trash and Debris Trash and debris > 5cf per 1,000 sf (one standard size
garbage can
Inlet/Outlet Pipe Inlet/Outlet pipe clogged with sediment and/or debris
material.
Sediment Accumulation in Pond
Bottom/Dredging Accumulation of sediment in bottom of pond
Water Level Standing water is present 2 days after a rainfall event
Erosion Erosion of the pond's side slops and/or scouring of the
pond bottom, that exceeds 6-inches, or where continued
erosion is prevalent.
Settlement of Pond Dike/Berm Any part of these components that has settled 4-inches or
lower than the design elevation, or inspector determines
dike/berm is unsound.
Internal Berm Berm dividing cells should be level.
Overflow Spillway Rock is missing and soil is exposed at top of spillway or
outside slope.
Trash and Debris Trash or debris that is plugging more than 20% of the
openings in the barrier.
Bars are bent out of shape more than three inches
Bars are missing or entire barrier missing.
Bars are loose and rust is causing 50% deterioration to any
part of barrier.
Inlet/Outlet Pipe
Debris barrier missing or not attached to pipe.
Vegetation Vegetation that reduces free movement of water through
the ditches
Eroded damage over 2 inches deep where cause of damage
is still present or where there is potential for continued
erosion
Any erosion observed on a compacted berm embankment
*Maintenance: Enter 1 if maintenance is needed and include WO#. Enter 2 if maintenance was performed same day.
Debris Barriers (e.g., Trash Racks)
Damaged/Missing Bars
Misc.
Erosion Damage to Slopes and
Channel Bottom
Y OR N
Inspection and Maintenance Checklist
Dry Ponds
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Wetland and Prairie Grass Maintenance Plan (Dry Pond)
Short –term: Year 1
1. The wetlands and prairie grass (native plantings) should be monitored weekly for the first
three months, and additional watering may be required to ensure the wetland plantings receive at
least 1 inch of rainfall or watering. No additional watering is necessary if the soil is wet at the
surface.
2. Monitor wetlands and prairie grass (native plantings) for growth of species not in the planting
plan (invasive species). Eliminate invasive plants at the soonest possible time. Hand weeding and
pruning is the preferred method for removing invasive plants. Spot applications of appropriate
herbicides may also be utilized. Determination of herbicide use and application should only be
completed by certified professional applicators. All manufacturers’ recommendations must be
followed.
3. Assure that wetlands and prairie grass (native plantings) or pond hydrology is maintained. If it
is not possible to maintain the hydrology of the planned wetlands and prairie grass watering the
plants may be necessary, or the re-establishment of plants may be necessary when the hydrology
is restored.
4. Mowing no shorter than 8” should be completed prior to the maturation of weed seed,
typically in late spring, mid-summer, and early fall. Do not mow in wet or muddy locations.
5. Remove sediment that has filled the sediment forebay or is inhibiting plant growth. Some
plant and/or mulch maintenance will likely be necessary with sediment removal.
6. Complete the first annual inspection of wetlands and prairie grass condition during the fall to
assess vegetation establishment. Replace dead plants if necessary.
Mid- and Long-Term: Year 2 and Beyond
During the second and succeeding years, more of the planned plant species will be more
noticeable and vigorous in their growth. Monitoring of the plantings during this period should be
twice per year at a minimum.
1. If dead vegetation accumulates and causes ponding in new areas, removal of the dead material
and any sediment may be necessary. During this time, planting new vegetation may be
necessary.
2. Monitor wetlands and prairie grass (native plantings) for growth of invasive species. Eliminate
invasive plants at the soonest possible time.
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Maintenance Inspection Checklist Page 3 of 9
DRY POND & WET POND
MAINTENANCE INSPECTION CHECKLIST
BMP Location: Inspector’s Remarks:
Overall Condition (circle one): ACCEPTABLE UNACCEPTABLE
Inspection Date:
FREQUENCY MAINTENANCE ACTIVITY COMMENTS
As Needed &
Following > 1”
Rainfall
Irrigate if plants appear wilted or unhealthy; replace dead plants
Check/repair areas with erosion, cracking, embankment failure, burrowing animals, and
sediment clogging the drain and other pipes
Repair erosion and bare soil
Remove woody vegetation < 15’ toe of embankment and mow < 25’ from spillway
Remove trash, debris, and sediment
Remove weeds and invasive plants
Monthly
(during growing
season)
Irrigate 1” water/week during the first growing season; maintain low water levels to allow
sufficient oxygen to the roots of establishing plants (wet pond shelf)
Check/clean inlets, outlets/overflows and trash racks from debris
Check plants for pest damage or disease
Remove trash, debris, and sediment
Semi-Annually
(spring & fall)
Check/remove sediment build-up and plant debris (especially < 18” of outlet)
Check water levels with design specifications (wet pond)
Check/repair any settlement of berms
Check/remove burrowing animals; repair holes in embankments
Annually Seed or sod to restore dead or dying grass/groundcover
Replace mulch every 3 years (min); replace topsoil every 10 years (min)
Remove accumulated sediment (> 50% capacity forebay, > 25% capacity pond). Minimum 2-
10 years (dry pond), 5-10 years (wet pond)
Upon Failure Redesign and reconstruct
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Maintenance Inspection Checklist Page 9 of 9
RIPARIAN RESTORATION & NATIVE REVEGETATION
MAINTENANCE INSPECTION CHECKLIST
BMP Location: Inspector’s Remarks:
Overall Condition (circle one): ACCEPTABLE UNACCEPTABLE
Inspection Date:
FREQUENCY MAINTENANCE ACTIVITY COMMENTS
As Needed &
Following > 1”
Rainfall
Irrigate if plants appear wilted or unhealthy; replace dead plants
Check for erosion and slope stability; repair with additional plant material similar to original
and/or small stones for stability
Remove trash, debris, and sediment
Remove weeds and invasive plants
Replace bark mulch on bare, exposed soil
Monthly
(during growing
season)
Irrigate 1” water/week during the first growing season
Check plants for pest damage or disease
Remove trash, debris, and sediment
Remove weeds and invasive plants
Semi-Annually
(spring & fall)
Check for erosion, embankment failure, and sediment accumulation
Prune/trim plants
Redefine landward edge
Add bark mulch
Annually Prescribed burn (prairie only) end of second year OR mow to very close to ground; remove
plant debris from site to expose soil to sun; repeat on 2 to 5 year cycle
Upon Failure Redesign and reconstruct
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