Stormwater Maintenance Form - 1201 2022_202301121236059250_v1
SEPTEMBER 2022 1
New Hanover County
STORMWATER SYSTEM OPERATION & MAINTENANCE PLAN AND AGREEMENT
The development and execution of this Operation & Maintenance (O&M) Plan and Agreement is a
required component of the Stormwater Management Plan (SWMP) described in Section 2.3.2 of the
New Hanover County Stormwater Design Manual. The SWMP is a prerequisite to obtaining a
Stormwater Permit and is kept on file in the office of the County Engineer. The required schedule and
procedures for the inspection, operation, and maintenance of all stormwater conveyance facilities and
stormwater control measures (SCMs) are identified below.
1 Stormwater Conveyance Facilities
Pipes, Culverts, Open Channels, Catch Basins, Inlets
As a minimum, the following maintenance items shall be performed:
_____ 1. Open channels, ditches, and swales shall be periodically, annually at a minimum and after any
major rainfall event such as a hurricane, tropical storm, or flooding, inspected for blockage
and erosion. They shall be kept free of undesirable growth and other forms of blockage and
mowed or maintained to the design cross-section and area as shown on the Stormwater
Management Plan accepted by the county and on file in the office of the County Engineer.
Growth on the slopes and bottom shall not exceed a height of 8 inches. Areas of excessive
channel or bank erosion shall be re-stabilized and maintained to mitigate potential further
erosion.
_____ 2. Storm drainage pipes, roof drain leaders and culverts shall be periodically, annually at a
minimum and after any major rainfall event such as a hurricane, tropical storm, or flooding,
inspected for debris and sand build-up. They shall be cleaned as necessary to provide for the
free conveyance of stormwater as designed.
_____ 3. Storm drainage catch basins and inlets shall be periodically, annually at a minimum and after
any major rainfall event such as a hurricane, tropical storm, or flooding, inspected for debris
and sand build-up. They shall be cleaned as necessary to provide for the free conveyance of
stormwater as designed.
NEW HANOVER COUNTY STORMWATER SYSTEM
OPERATION & MAINTENANCE PLAN AND AGREEMENT
SEPTEMBER 2022 2
2 Stormwater Control Measures (SCMs)
Detention, Infiltration/Retention
As a minimum, the following maintenance items shall be performed:
_____ 1. The inspection schedule and operation and maintenance provisions for all SCMs shall be
performed per the general O&M requirements indicated in Part A-7: Operations and
Maintenance, and the specific O&M requirements for individual SCMs indicated in Part C:
Minimum Design Criteria and Recommendations for Stormwater Control Measures of the
NCDEQ Stormwater Design Manual.
_____ 2. An NCDEQ O&M EZ form shall be completed for each SCM included in the Stormwater
Management Plan accepted by the county and on file in the office of the County Engineer.
_____ 3. Grassing around any detention/retention facility shall be maintained to prevent the erosion of
these areas. The areas shall be mowed to maintain the aesthetic quality of the site and to
prevent erosion and a reduction in capacity of the stormwater system.
_____ 4. Landscaping of the area around the detention/retention facility shall be maintained and shall
not reduce the capacity or hinder operation and maintenance of the stormwater system.
_____ 5. The detention/retention facility shall be maintained at the design depth as shown on the
Stormwater Management Plan accepted by the county and on file in the office of the County
Engineer. Debris and sedimentation shall be removed if:
_____ a. The primary outlet capacity is impaired or clogged, and/or
_____ b. The depth of the facility is more than one foot above the original facility depth, or
the facility volume is reduced by 25% of the design impoundment volume.
_____ 6. Pipe installed to provide detention shall be kept free of sediment build-up. The detention
facility shall be maintained in accordance with the design volume as indicated in the
Stormwater Management Plan accepted by the county and on file in the office of the County
Engineer. Debris and sedimentation shall be removed if:
_____ a. The storage volume is reduced by 25% or more, and/or
_____ b. The sediment and/or debris restricts the free flow of stormwater.
_____ 7. The pipes, stone, and soils installed to provide infiltration shall be kept free of sediment build-
up. The infiltration system shall be maintained in accordance with the design infiltration
capacity as indicated in the Stormwater Management Plan accepted by the county and on file
in the office of the County Engineer. Debris and sedimentation shall be removed if:
_____ a. The design infiltration capacity is impaired, and/or
_____ b. The sediment and/or debris restricts the free flow of stormwater into the
infiltration system and surrounding soils.
_____ 8. The infiltration system shall be removed and replaced with new material when the system no
longer permits the stormwater to freely infiltrate within 5 days into the surrounding soils by
proper maintenance.
NEW HANOVER COUNTY STORMWATER SYSTEM
OPERATION & MAINTENANCE PLAN AND AGREEMENT
SEPTEMBER 2022 3
3 Agreement Certification
I acknowledge and agree by my signature below that I am responsible for the inspection, performance
and maintenance procedures listed above, and those described on the attached NCDEQ O&M EZ form
for each SCM included in the Stormwater Management Plan accepted by the county and on file in the
office of the County Engineer. I agree to notify New Hanover County of any problems with the system
and prior to any changes to the system, or the change of responsible party.
Print Name: ______________________________________________________________________
Title: ______________________________________________________________________
Address: ______________________________________________________________________
Phone: ______________________________________________________________________
Date: ______________________________________________________________________
Signature: ______________________________________________________________________
I, __________ _____________, a Notary Public for the State of _________________________,
County of ______________________do hereby certify that __________
personally appeared before me this _ ___ day of ______ ___, 20 ___, and acknowledge
the due execution of the foregoing maintenance agreement requirements.
Witness my hand and official seal,
SEAL
My commission expires: ________________________________