Subtask3_15_RecommendationsLocalStormwater

Subtask 3.15: Recommendations for
Developing and Maintaining Local
Stormwater Management Programs
North Carolina Flood Resiliency Blueprint
Prepared for the North Carolina Department of Environmental Quality by AECOM
July 2024
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North Carolina Flood Resiliency Blueprint
Table of Contents
Acronyms ........................................................................................................................ iv
Definitions ....................................................................................................................... v
1 Local Stormwater Maintenance Programs ................................................................... 1
1.1 Background of Stormwater Management and Maintenance Program Development.. ............ l
1.1.1 Maintenance Activities ................................................................................................ 4
1.1.2 The Costs of SCM Maintenance ................................................................................... 5
1.1.3 Maintenance Strategies ............................................................................................... 6
2 Recommendations ...................................................................................................... 9
2.1 Funding Recommendations ....................................................................................................... 9
2.1.1 Recommendation 1: Develop Standard Finance Methods ........................................ 9
2.1.2 Recommendation 2: Develop Supplemental Finance Methods .............................. 10
2.1.3 Recommendation 3: Develop Funding Support ....................................................... 12
2.1.4 Recommendation 4: Provide Grant Opportunities to Establish Stormwater
Program(s) ................................................................................................................. 13
2.1.5 Recommendation 5: Technical Advisory Group (TAG) Request to Develop a
Centralized State Funding Site ................................................................................. 14
2.2 Planning, Data, and Maintenance Recommendations ............................................................ 15
2.2.1 Recommendation 6: Develop Planning Support ...................................................... 15
2.2.2 Recommendation 7: Develop Data Management Support ...................................... 16
2.2.3 Recommendation 8: Develop Maintenance Document Support ............................. 17
2.2.4 Recommendation 9: Support the Development of Regional Stormwater
Utilities and Partnerships .......................................................................................... 17
3 References ................................................................................................................ 19
4 Appendix .................................................................................................................. 20
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North Carolina Flood Resiliency Blueprint
Figures
Figure 1. Distribution of stormwater fee structures in NC communities by billing period (UNC-
CH EFC 2023) ............................................................................................................................. 3
Figure 2. Fee collection methods used by MS4 permit communities in NC (UNC-CH EFC 2023) ............. 4
Figure 3. Annual routine maintenance costs of common NC SCMs (inflation-adjusted to 2023
dollars) ...................................................................................................................................... 6
Figure 4. Maintenance activities by strategy type (Hunt, Waickowski, and Lord 2021) ........................... 7
Tables
Table 1. Common maintenance issues and tasks for NCDEQ-approved SC Ms ........................................ 5
Table 2. The LASII program's Local Government Unit Indicators for Spring 2024 applications ............ 14
Table 3. Regional organizations/partnerships concerned with stormwater management ................... 18
Table 4. Additional specific maintenance tasks for common NCDEQ-approved SC Ms (Hunt,
Waickowski, and Lord 2021) ................................................................................................... 20
Table 5. Cost, community & environmental issues for SCMs (NCDEQ 2018) .......................................... 21
Table 6. NC-based stormwater management certifications and training .............................................. 21
Table 7. Stormwater wetlands routine maintenance costs and characteristics in North Carolina
2018 (Hunt, Waickowski, and Lord 2021) ............................................................................... 23
Table 8. Bioretention cells routine maintenance costs and characteristics in North Carolina
2018 (Hunt, Waickowski, and Lord 2021) ............................................................................... 23
Table 9. Wet ponds routine maintenance costs and characteristics in North Carolina 2018
(Hunt, Waickowski, and Lord 2021) ....................................................................................... 24
Table 10. Dry ponds routine maintenance cost characteristics in North Carolina 2018 (Hunt,
Waickowski, and Lord 2021) ................................................................................................... 24
Table 11. Sand filters routine maintenance costs and characteristics in North Carolina 2018
(Hunt, Waickowski, and Lord 2021) ....................................................................................... 25
Table 12. NC Stormwater Design Manual required inspection frequency for SCMs (NCDEQ 2018) ....... 26
Table 13. Reporting data for stormwater maintenance costs: best management practice (BMP)
facility information (facility information is provided in one record and then related
to multiple maintenance records in Table 14) (Clary and Piza 2017) .................................. 27
Table 14. Reporting data stormwater maintenance costs: maintenance event records for the
facility (multiple event records over time, linked to the facility information in Table
13) (Clary and Piza 2017) ........................................................................................................ 28
Table 15. Reporting data for stormwater maintenance costs: maintenance activity records
(activities conducted during maintenance events defined in Table 13) (Clary and
Piza 2017) ................................................................................................................................ 29
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Acronyms
ARPA -American Rescue Plan Act
BMP -Best Management Practice
DWI -Division of Water Infrastructure
DWR -Division of Water Resources
EFC -Environmental Finance Center
ERU -Equivalent Residential Unit
LASII -Local Assistance for Stormwater
Infrastructure Investments
MS4 -Municipal Separate Storm Sewer System
NC -North Carolina
North Carolina Flood Resiliency Blueprint
NCDEQ -NC Department of Environmental
Quality
NCDOT -NC Department of Transportation
RBA-River Basin Association
SCM -Stormwater Control Measure
SWIA-State Water Infrastructure Authority
TAG -Technical Advisory Group
UNC-CH -University of North Carolina at
Chapel Hill
WRRI -Water Resources Research Institute
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Definitions
A comprehensive list of definitions applicable to multiple Flood Resiliency Blueprint documents is
provided in a separate document.
Stormwater Control Measures: "permanent structural devices that are designed, constructed,
and maintained to remove pollutants from stormwater runoff before the water reaches our
streams and drinking water supply reservoirs." {NCDEO )
Retrofits: "SCMs that provide nutrient and/or sediment loading reduction from existing
development that is currently untreated or is inadequately treated by an existing SCM. Besides
providing stormwater treatment, retrofits can help alleviate flooding and erosion problems, and
some can become an attractive community amenity." (NCDEO Stormwater BMP Manual 2017)
Floodplain Management: a community-based effort to prevent or reduce the risk of flooding,
resulting in a more resilient community. (FEMA)
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North Carolina Flood Resiliency Blueprint
1 Local Stormwater Maintenance Programs
This report provides recommendations for developing and maintaining local stormwater
management and maintenance programs associated with developing the North Carolina (NC) Flood
Resiliency Blueprint (Blueprint). The recommendations include the level of resources required to
maintain these programs, possible funding sources, and ways to address the funding gaps of small,
under-resourced communities.
1.1 Background of Stormwater Management and Maintenance
Program Development
Previous work under the following subtasks was considered a basis for the recommendations herein.
As discussed in these previous subtasks, stormwater maintenance programs are essential for
protecting the success of flood resilience projects.
Subtask 1.1-Literature Review and Data Collection Inventory
Subtask 1.4 -Catalogue of Government and Organization Watershed Planning Efforts in the
Neuse River Basin
Subtask 1.7 -Statewide Planning Efforts with Flood Resilience Recommendations
Subtask 2.6 -Flood Risk Reduction Project Funding Analysis
Subtask 2.9 -Project Restrictions Analysis (forthcoming)
Stormwater programs ensure drainage systems remain clear and functional, reducing the risk of
blockages and overflow from heavy rainfall. This proactive management can reduce the impacts of
flooding by protecting infrastructure and safeguarding communities from flood-related damages.
However, due to their complexity and cost, they can be challenging to organize and finance.
Stormwater maintenance programs can provide oversight and ongoing maintenance of a
community's various stormwater-related responsibilities, such as storm drainage, water quality
regulations, retrofits, floodplain management, and open space amenities. Any one of these functions
can involve multiple local government departments or entities responsible for urban drainage,
floodplain management, stormwater quality regulations, parks and open space, and transportation.
Communities use stormwater maintenance programs to achieve multiple sustainability, quality of
life/livability, and flood resiliency goals. However, incorporating flood resiliency goals can be a
complex process with the potential to add additional challenges if mismanaged.
Stormwater maintenance programs generally follow one of two funding management approaches for
storm drainage, water quality, mitigation of land-use impacts, and floodplain management, including:
The tax-supported public works model
The fee-based stormwater utility model
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The tax-supported public works model generates funding through local government-levied tax
revenue. This approach has the challenge of competing with other departments for tax funding;
however, it may not receive public criticism for charging a fee or a "rain tax." Recent stormwater
utility data collected by the Environmental Finance Center (EFC) at the University of North Carolina at
Chapel Hill (UNC-CH) in 2023 reported the average service population of a jurisdiction using a tax-
supported public works model to be approximately 25 ,800. Conversely, the stormwater utility model
generates revenue through fees charged to properties that are part of the municipality's stormwater
system. The stormwater utility model enjoys having a relatively stable funding source (stormwater
fee) but also incurs the additional administrative costs and burden of setting up and maintaining the
billing and collection data associated with charging a stormwater fee. The average service population
of approximately 53,000 for communities using a fee-based model, more than double the size of
communities using a tax-supported public works model, reflects the burden of additional costs and
staff required to operate this funding management approach. The fee-based model typically uses one
of three different fee structure types: flat fees, tiered flat fees, or uniform rates.
Flat fees charge all properties the same fee, regardless of land use/imperviousness, and have the
benefit of reducing data collection and administrative costs .
Tiered flat fees are charged to properties based on the estimated impervious surface area of the
parcel, which is grouped into different tiers.
A uniform rate, also called an Equivalent Residential Unit (ERU), is like tiered flat fees in that it
charges properties based on impervious surface area . Unlike tiered flat fees, uniform rates are
determined by dividing the impervious surface area of a property by a standard measure of
expected runoff based on the property's land uses and then multiplying that by the monthly fee
per ERU.
Each financing structure can have one of four billing periods: bi-monthly, monthly, semi-annually, and
annually. The distribution of stormwater fee structures by the fiscal year 2022-23 billing period can be
reviewed by land use type in Figure 1 below.
It is essential to point out that a hybrid approach can be taken. There is no prohibition of charging a
stormwater fee to generate revenue to support a tax-supported public works department. Care must
be taken to ensure the revenues generated from the stormwater fee cover costs associated only with
the operation and maintenance of the stormwater system .
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North Carolina Flood Resiliency Blueprint
Uniform Rate 12
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~ Tiered Flat Fees 1 E
:,
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Flat Fee
Uniform Rate
iii 19
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C:
QJ
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Uniform Rate 1
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Tiered Flat Fees QJ
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Flat Fee
0% 20% 40% 60 % 100%
■ Bi-month ly ■ Monthly ■ Semi-annually Annually
Figure 1. Distribution of stormwater fee structures in NC communities by billing period (UNC-CH EFC 2023)
Stormwater utility data collected by UNC-CH EFC in 2023 reported billing methods based on 93
reporting utilities; of these, 64 charge their customers through a combined utility bill (fee-based
model), 21 charge for their services on the customer's property tax bill (tax-supported model), and an
additional eight utilities send separate stand-alone bills; the latter broadly represents counties and
municipalities where other utilities, such as water, sewer, or electric, may not be offered (UNC-CH EFC
and NCDEQ-DWR 2020; Sanchez 2023). Five of the six large Municipal Separate Storm Sewer Systems
(MS4) regulated under Phase I of the National Pollutant Discharge Elimination System in NC -
Fayetteville being the exception -have implemented the fee-based stormwater utility model (Figure
2 ). Of the 73 medium-sized MS4 communities included in Phase II, a majority (47) use utility bills,
compared to only 13 Phase II communities that use property tax bills. All four reporting counties
(Camden, Granville, Mecklenburg (unincorporated), and Person) use stand-alone utility billing.
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North Carolina Flood Resiliency Blueprint
None
Waiver
Ph ase II
Ph ase I
0% 10 % 20% 30% 4 0% 50% 60% 70% 80% 90% 100%
■ Pr-o p erty Tax Bi ll ■ Ut i l ity Bi ll ■ Stand-al one Bi ll Non e
Figure 2. Fee collection methods used by MS4 permit communities in NC (UNC-CH EFC 2023)
The costs to maintain, repair, and eventually replace stormwater infrastructure can be substantial
depending on the number and types of stormwater assets . Developing and financing robust programs
can pose significant challenges in small communities where these costs represent a significant
portion of a municipality's operating budget. When planning for stormwater asset maintenance,
communities must consider the types of stormwater infrastructure, routine and restorative
maintenance costs, personnel and training requirements, service life, and eventual replacement
costs. Key considerations are included in the following sections.
1.1.1 Maintenance Activities
Different stormwater assets (e .g., pipes, culverts, inlets, etc.) and stormwater control measures (SCMs)
require different maintenance to meet their intended functions. Maintenance of stormwater assets
and documentation of standard maintenance procedures are requirements for permitted MS4s.
Personnel performing inspection and maintenance should be familiar with the specific requirements
for each inspected asset and device, including maintenance activities, equipment, and frequency .
Resources allocated for stormwater maintenance activities should consider staff training and/or
certification expenses. Common maintenance issues and related activities for NCDEQ-approved SCMs
can be reviewed in Table 1 below. Additional specific maintenance tasks for common NCDEQ-
approved SC Ms (Hunt, Waickowski, and Lord 2021) can be reviewed in Table 4 of the Appendix.
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North Carolina Flood Resiliency Blueprint
Table 1. Common maintenance issues and tasks for NCDEQ-approved SC Ms
SCM Element Issue Maintenance Task
Entire SCM Trash/debris present Remove trash/debris
Areas of bare soil and or erosive Regrade the soil to remove the gully,
Perimeter of SCM
gullies; surrounding vegetation (if plant, and water ground cover until
applicable) is too short or too established, and apply a one-time
long. fertilizer.
A pipe is clogged or damaged (e.g.,
Unclog or replace pipe; regrade swale and
Inlet device (pipe or swale) cracked); erosion occurring in
provide erosion control devices
swale
Sediment accumulation reduces
the depth to 75% of the original Identify the sediment source and remedy;
Forebay or pretreatment
design depth or depth greater remove and dispose of sediment; provide
than six inches; erosion occurs, or additional erosion control devices;
area
riprap is displaced; weeds are remove plants by hand; regrade to direct
present; runoff bypasses runoff to the pretreatment area.
pretreatment.
Visible layer of accumulated
Identify sediment source and remedy;
sediment; standing water for more
remove and dispose of sediment; replace
Main treatment area the top few inches of media and
than five days after storm event
revegetate; consult a professional if the
(SCM dependent)
issue persists.
Shrubs or trees present; rodents
Remove shrubs or trees; use traps to
Embankment present; annual inspection shows
remove rodents; make necessary repairs.
need for repair
Outlet device Clogging: the device is damaged
Unclog the device; repair or place the
device
Erosion or other signs of damage Contact the NC Division of Water
Receiving water
have occurred Resources (NC DWR)
1.1.2 The Costs of SCM Maintenance
When budgeting for stormwater asset maintenance and replacement, communities should consider
replacement cost, estimate service life, and set up a fund to budget for eventual asset replacement
spread across the expected service life. The total annual budget for the stormwater asset or facility
would incorporate anticipated yearly inspection and maintenance costs plus the annual replacement
budget spread across an asset's service life.
A 2021 study by researchers at the North Carolina Water Resources Research Institute (NC WRRI)
reported maintenance costs for SCMs in NC (see the Appendix -Tables 7-11 ) for common SCM cost
estimates in dollars per acre of SCM site). The study also cited relevant cost considerations and
various reporting methods for annual operation and maintenance costs (e.g., as a percent of
construction cost, as a function of SCM drainage area or footprint, etc.) for NC and other geographies
(Hunt, Waickowski, and Lord 2021). A summary of annual routine maintenance costs, inflation-
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North Carolina Flood Resiliency Blueprint
adjusted to 2023 dollars, from the NC WRRI study can be reviewed below in Figure 3. These costs
include labor, equipment, and material considerations. The study also found that private contractors
or multiple municipal departments usually maintain municipal SCMs. Further, larger municipalities
often share maintenance responsibilities across departments, making collecting and tracking costs
more challenging. Smaller, more resource-limited communities with fewer staff may be more likely to
hire private contractors to perform stormwater maintenance activities.
underground commercials and Filter
underground Residential sand Filter
Above Ground sand Filters -$21 -0
-$16.5
Bio retention cells with Grass -$19.4
$16.7
Bioretention CellsWith Mulch • $15 •4
$14.8
Dry Pond -$l4 .l
-$8.6
wet Pond -$11.7
-$7.9
sto rmw aterwetland -$13.6
-$10.l
$0 $20
$113.4
$90.9
$40 $60 $80 $100 $120
Thousands of Do Ila rs per Acre of SCM Surface Area
■With Mowing($/ac) ■Witho utMow ing($/ac)
Figure 3. Annual routine maintenance costs of common NC SC Ms (inflation-adjusted to 2023 dollars)
1.1.3 Maintenance Strategies
Annual costs to maintain stormwater assets such as SCMs should consider routine (i.e.,
preventative/proactive) and restorative (i.e., remedial, more significant, and typically more costly)
maintenance (Figure 4). Routine/preventative maintenance represents general, usually relatively
low-cost, and more frequent upkeep, such as trash removal, mowing, and mulching; routine
maintenance activities are intended to prevent the costliest maintenance and/or replacement
activities. Restorative maintenance includes relatively more costly tasks to restore an SCM or other
stormwater asset's functionality, often due to a lack of proper or routine maintenance. It should be
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noted that in the context of this report, with or without mowing refers to mowing an SC M's
surrounding landscape. Mowing the surrounding landscape of an SCM is a common maintenance
practice. However, the practice is more applicable to certain SCMs than others. For example, mowing
is commonly conducted around wet and dry ponds to ensure typical landscaping activities do not
negatively impact the ponds and that the immediate upstream watershed remains stable.
In contrast, stormwater wetlands tend not to have perimeter mowing due to the different ecological
sensitivities, soil conditions, and intended functions. In the case of bioretention cells, cells with grass
refer to the estimated cost of mowing both the SCM's surrounding landscape and the SC M's interior
area . Bioretention cells with mulch slightly reduce the overall maintenance cost as only the
surrounding landscape would be mowed, excluding the mulched interior area of the cell. Though the
routine maintenance activity of mowing is relatively inexpensive compared to proactive and
restorative practices, mowing can be a major cost consideration. As this report provides estimated
costs and common proactive, routine, and restorative maintenance practices, the cost associated
with these practices will depend on the implementor's intended function for the SCM in question and
requires site-specific details to determine.
Proactive
•Controlling weeds and other
undesired plants
• Cleaning/scraping filter
media
• So il testing
• So il aeration
• Vegetation replacement
• Fertilization
•Irrigation
• House and pipe connections
inspected for leaks
• Disinfection
Routine
• Inspections
• Trash remova l
•Sediment removal
• Prun ing of woody vegetation
• Th inning of vegetation
•Side slope stab ilization
•Mowing
•Mulching
• Testing pavement surface
infiltration rates
Restorative
• Media /soil replacement
•Inlet/outlet structu re repai r
•Conveyance system repair
• Disease control fo r
vegetation
• Denund i ng overgrown/over-
run practice by unwanted
species
• Embankment, dam, and
channel repair due to erosion
or rodents
•Wound dressing for
vegetation
• Vacuum sweep ing of
permeable pavement
Figure 4. Maintenance activities by strategy type (Hunt, Waickowski, and Lord 2021)
In addition, merging services into an existing program, from parks to open spaces and sustainability
components, necessitates different paradigms for financing. The merged stormwater program
development and funding decisions must consider both discretionary and mandated services as well
as the following key components necessary to develop and maintain a stormwater maintenance
program:
Planning efforts and stakeholder engagement (e.g., impacted communities, experts, etc.)
Basin-specific knowledge
Community-specific knowledge (e.g., hazards, vulnerability, economic conditions, etc.)
Data and modeling
Understanding of state and federal requirements and restrictions
Stormwater retrofits that fit the individual community needs and challenges
Inspection, maintenance, and operations for stormwater retrofits
Technical training and certification
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Staffing, resource administration, and allocations
Identify long-term program funding and provide funding administration and assistance
Generally, the most common process for considering whether to fully or partially fund a local
stormwater program is as follows:
Establish an advisory committee or similar diverse group to advise the elected officials during and
at the end of the process
The advisory committee defines the following in an iterative process:
Extent of Service : this is the geographic area where the stormwater program will provide
services (watershed(s), municipality-wide, county-wide, etc.). State General Statute has
restrictions when there is more than one entity providing stormwater services within the
same jurisdiction.
Level of Service : to what degree services are provided by the public system is determined
in this step. Are all services provided just within the road right-of-way, outside the right-of-
way, both, etc.? Are some services only available outside the right-of-way, like
maintenance of SCMs?
Cost of Service : how the fees are calculated (flat fees, tiered fees, and uniform rate/ERU),
and the billing system (included in the annual tax bill, municipal services bill, or water-
sewer bill) are usually identified in this step.
The advisory committee and local government staff report back to elected officials with progress
and recommendations. The elected officials can support the recommendations, modify them, and
then provide additional direction to the advisory committee and staff on the next steps. Another
option for this step is for the elected officials to decide not to pursue a stormwater fee.
Local government staff, contractors, or a combination of the two, create draft stormwater
ordinances that codify policy decisions to date and provide more specifics on stormwater fees -
for example, the stormwater fee credits, waivers, or exemptions that will be provided and under
what conditions these are provided.
Elected officials consider adopting the draft stormwater ordinance and endorse staff
recommendations on staffing and organizational structure of the stormwater program.
Refer to previous sections under Task 2 for specific details and context of areas and items listed
above.
Subtask 2.6: Flood Risk Reduction Project Funding Analysis
Subtask 2.9: Project Restrictions Analysis
Given stormwater maintenance programs' complexity and operation costs, from basic drainage
networks to complex multifunctional systems, the two standard funding approaches may not be
practical for small, under-resourced communities. Therefore, in alignment with the Blueprint's goal of
building flood resilience statewide, the following recommendations are made to provide a
development process for stormwater maintenance programs and activities that apply to NC
communities of all sizes and compositions.
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2 Recommendations
2.1 Funding Recommendations
Local governments face various choices when organizing stormwater maintenance programs; no
single model fits every community. The program's organization will depend on the community's
values and the conditions (good, failing, aging, undersized, etc.) of its utilities and public works
services. Smaller programs that address limited functions like drainage and water quality services
would be easier to finance with user charges than full-featured programs that include floodplain
management, parks, and recreation.
Combining stormwater, floodplain management, and community services creates challenges for
policymakers who work with impacted property owners in communities where the economics of
stormwater programs blend the financing and floodplain management of excess water. Drainage can
be individual when attached to single parcels, but further down the line, the stormwater runoff
becomes increasingly public as it serves larger areas. Stormwater quality is a mandated
environmental service impacted by a mixture of public and private sector facilities. Floodplain
management considers public and private interests by benefitting individual properties and the wider
community.
Below are recommendations to provide funding support for the development and/or maintenance of
stormwater maintenance programs across NC. These recommendations apply to NC communities of
all sizes and compositions as well as regional organizations composed of multiple local, county,
and/or NGO organizations.
2.1.1 Recommendation 1: Develop Standard Finance Methods
Program finance depends on the community size, resources, scale of operation, organization,
approach to taxation, and use of fees. Generally, using fees has the advantage of creating a new
revenue stream to relieve the burden on general taxes. Although community members still pay the
charge, it assigns charges according to the impact an individual property has on the community. The
following are recommended potential standard finance methods that can be used during the program
development stage:
Traditional methods:
Tax-supported public works model
Fee-based stormwater utility model based on impervious area
Alternatives or modified methods:
Municipal development of a small storm drain fee by rate-setting. The community would use
water service bills with a rate schedule based on land uses, and area use multipliers for
impervious areas that exceed the community's stormwater, development, and/or other
governing ordinances. This water service bill rate schedule would also be adjusted based on
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indicators of vulnerable and under-served communities. Following this approach,
communities can link land use decisions to charges and influence the shape and sustainability
of the community.
Municipal development of a fee-based stormwater utility with maintenance and operations
where stormwater control measures or infrastructure fees paid by private development are
required for municipalities to take over ownership.
Development of a stormwater enterprise utility in a community, in multi-communities, for a
regional area, or an entire basin or watershed.
A stormwater enterprise utility is where a town, city, regional government, etc.,
establishes a dedicated fund to be used only for stormwater work. The fund is
supported through a fee collected at regular intervals (often quarterly) from individual
properties to recover the cost of safely collecting, conveying, detaining, treating, and
disposing of stormwater. This enables stormwater enterprise utilities to operate
independently from general fund appropriations, supporting consistent operations
that are essential for the long-term monitoring and maintenance requirements of
operating stormwater infrastructure.
2.1.2 Recommendation 2: Develop Supplemental Finance Methods
In jurisdictions where fees are not feasible, creating supplemental finance methods can reduce the
financial burden for smaller, under-resourced communities while maintaining and supporting the
long-term needs of the stormwater maintenance program. Potential methods can include one of the
following:
Develop a supplemental finance method similar to the State Street-Aid (Powell Bill) Program or
increase the Powell Bill Program amounts based on the community stormwater program's SCMs.
The Powell Bill Program provides state aid to municipalities to resurface streets annually. 75% of
the funding is based on population, and 25% is based on the number of municipality-maintained
street miles. In 2022, the total appropriation for the program was $154,891,601, with an average
appropriation to municipalities of $305,000 (NC DOT 2022).
Develop supplemental local stormwater credit trading systems that fund stormwater control
measure maintenance, expansion, or new measure development. The concept is that a
stormwater credit trading system is established where negative, unavoidable impacts to
stormwater systems occur because of the increased volume of stormwater runoff. Increasing the
volume of stormwater runoff subsequently increases the severity or frequency of local flood
events due to the impacts of new developments (residential, commercial, highways, airports,
etc.). Like water quality-oriented mitigation banking, developers purchase credits from a local or
regional government managing the bank to offset their impacts on the community's stormwater
system. These credits are created through the activities of other property owners who voluntarily
installed or retrofitted SCMs on their properties (on-site) at relatively low costs or by the
governing body that operates the trading program with the intention of selling stormwater
credits. The resulting revenue would then be dedicated to implementing, maintaining, and
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expanding/enhancing new and existing SC Ms. Care should be taken to implement offsetting
measures in the same eight-digit hydrologic unit codes (HUCs) where the impacts occurred,
mirroring the United States Army Corps of Engineers regulations for water quality-oriented
mitigation banking. Limiting the sale and purchase of these credits to eight-digit HU Cs ensures
that the cumulative impacts of development for which the credits are offsetting, directly mitigate
the impacts to stormwater systems . The District of Columbia's (D.C.) Department of Energy and
Environment was established in 2013 as one of the first volume-based stormwater credit trading
programs in the U.S. A more recent example of a municipal, volume-based credit trading program
is the City of Grand Rapids, which established its program in 2023. In partnership with American
Rivers, a nonprofit organization, the city established the program in concert with developer-
responsible mitigation and an in-lieu fee in response to a revision of the municipal separate storm
sewer system (MS4) individual permit that increased requirements for development and
redevelopment projects (US EPA 2023).
For more information on stormwater credit trading programs, please review Establishing
a Stormwater Volume Credit Trading Program: A Practical Guide for Stormwater
Practitioners (2019), which Stormwater Currency, a group of stormwater project financing
experts, prepared. Stormwater Currency's guide can be found through the link below.
https://www.americanrivers.org/wp-
content/uploads/2019/09/AR StormwaterVolumeCreditTrading Final.pdf
Develop a priority funding mechanism/finance method for a yearly basin or watershed mitigation
project for each region across the state. This could be modeled after multiple programs, but the
Superfund -Inactive Hazardous Sites program could be used as a guide. Such a program could be
developed where previous SCMs no longer function due to lack of maintenance and are assessed
and ranked. NCDEQ, or another state agency responsible for managing the program, would
receive and allocate the annual funding to address the deficiencies of the SCM and develop a
comprehensive maintenance (asset management) plan that includes a responsible party. Initially,
the Flood Resiliency Blueprint Tool should be used to rank the action (project), and this primary
funding mechanism will be identified when a funding strategy accompanies each action. Over
time, modifications to this new program should be considered if actions to rehabilitate SCMs in
under-resourced communities consistently receive low rankings and/or actions are not
implemented due to a lack of resources (staff).
Include the development or updating of stormwater inventories as an eligible activity for
Blueprint funding, prioritizing regional/multi-county/multi-community data collection and
inventory development proposals in support of Recommendation 9: Support the Development of
Regional Stormwater Utilities and Partnerships of this report and Recommendation 4.6.3,
Implement Multiple Finance and Organizational Approaches to Address Local Stormwater
Programs from the Draft North Carolina Flood Resiliency Blueprint.
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2.1.3 Recommendation 3: Develop Funding Support
Establish a repeatable, long-term statewide methodology for funding stormwater programs, including
small, under-resourced communities. Community policymakers seek organizational structures that
make sense to them and are affordable through workable financial arrangements. Provide options to
the communities for funding key aspects of their programs, such as planning, design, implementation,
and sustainability. Recommended activities include:
Develop direct contact from the state by basin or region. Establish basin-level or regional
contacts, identify funding resources for local communities, and assist with funding proposals.
Work with participating communities that have received Blueprint funding to develop asset
management plans for the planning, design, construction, and/or maintenance of SC Ms. Given the
best available data, these plans should include a detailed accounting of the estimated operation
and maintenance costs over the SCM(s) 's service life. As a component of the long-term costs of
SC Ms, financial assurances should be made and detailed in the asset management plan to ensure
the project maintains the necessary fiscal resources to realize its maximum service life. Financial
assurances are often made through bonding or insuring the stormwater assets to ensure the
project sponsor can cover the costs associated with long-term maintenance, repairs, and
potential liabilities.
Assume economic responsibility for the assurance of Blueprint-funded SC Ms where an accepted
project sponsor does not have the financial resources to adequately demonstrate their ability to
maintain the SCM to its full-service life. In circumstances where the Blueprint has approved a
community's request for funding, but that community meets certain economic and social criteria
(to be determined by NCDEQ) that indicate the applicant does not have the financial capacity to
assure the proposed SCM(s) over its long-term service life, NCDEQ would assume economic
responsibility for bonding or insuring that Blueprint funded SCM. The Blueprint can mitigate some
risks associated with assuming this kind of financial responsibility by providing surety bonds. In
long-term stormwater operation and maintenance, a surety bond is a financial guarantee
ensuring that the stormwater utility or developer maintains and operates the stormwater facilities
according to required standards. If the responsible party fails to meet these obligations, the surety
company covers the costs, providing financial assurance and risk mitigation for the entity
requiring the bond, i.e., NCDEQ. This bond protects public interests and environmental quality by
ensuring proper long-term maintenance of stormwater systems.
One example similar to Blueprint's proposed financial assurance strategy for stormwater-
related actions is the City of Raleigh, NC's Sediment and Erosion Surety process. Raleigh's
"Sediment and Erosion (S&E) Surety process applies when a developer requests to receive
a permit for land disturbing for a site either through a Mass Grading Permit, Building
Permit, or a Site Permit. The purpose of the surety is to protect downstream property
owners from erosion in the event work stops on the site, and the applicant is no longer
able to maintain Erosion Control measures. The surety will cover permanent stabilization
for the disturbed area permitted." (City of Raleigh 2024)
Provide a contact for assistance with funding administration.
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Develop a simple state audit process for the local stormwater program financials that can be used
for federal and state grant funding submittals.
Assist the community with developing community landscape documentation for funding
activities.
2.1.4 Recommendation 4: Provide Grant Opportunities to Establish
Stormwater Program(s)
In 2021, the NC General Assembly appropriated $1.69 billion from the state's allocation of the
American Rescue Plan Act (ARPA) for drinking water, wastewater, and stormwater investments in
Sections 12.13 and 12.14 of the Current Operations Appropriation Act of 2021 (Session Law 2021-180).
Approximately $100.5 million was allocated for stormwater projects in the Local Assistance for
Stormwater Infrastructure Investments (LASII) fund. NCDEQ's Division of Water Infrastructure (DWI)
was charged with administrating these monies, of which approximately $82 million was allocated to
fund projects for improving and/or creating infrastructure for controlling stormwater quantity and
quality. Grant types available from the LASII fund included construction grants (approximately 70% of
allocated funding) and planning grants (approximately 30% of allocated funding). Implementing a
stormwater utility was also an eligible use of LASII funding through stormwater construction funds.
Funds were awarded to eligible municipalities through OWi's competitive funding process. In
partnership with the State Water Infrastructure Authority (SWIA), DWI established a Priority Rating
System for stormwater infrastructure investments based on federal and statutory requirements and
stakeholder input. Through the LASII program, DWI awarded approximately $75.7 million in its Fall
2022 funding round and an additional $6.3 million in its Spring 2023 funding round across 95 projects.
It is essential that the Blueprint develop funding support focused on supporting NC communities that
would otherwise be unable to implement or effectively maintain a flood-resilient stormwater
maintenance program. To this effect, the LASII program has two eligibility requirements, including 1)
a documented stormwater quality or quantity issue and 2) demonstrating that the community would
experience significant hardship raising the revenue necessary to finance stormwater management
activities within its jurisdiction. Under LASII, significant hardship is defined as those communities
meet the following standards:
For applications for Stormwater Construction and Stormwater Planning Grants (except
applications to develop and implement a new stormwater utility)
City/County has a stormwater enterprise fund and an operating ratio of less than 1.00, OR
At least two of five Local Government Unit Indicators Table 2 for a city or county are worse
than state benchmarks OR
Entity does not meet the criteria but has stormwater projects that serve or benefit
disadvantaged areas within its jurisdiction
75% or more of project cost must be used to serve or benefit disadvantaged areas
For applications to develop and implement a new stormwater utility
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If the city or county does not have a stormwater enterprise fund and the application is to
develop and implement a new stormwater utility
Will have met the requirement to demonstrate significant hardship
Grant amount will be limited based on the number of Local Government Unit Indicators
that are worse than state benchmarks
Table 2. The LASII program's Local Government Unit Indicators for Spring 2024 applications
Population Change <= 3.13%
Poverty Rate >= 13.70%
Median Household Income <= $60,516
Unemployment Rate >= 4.90%
Per Capita Appraised Value of Property <= $133,264
Because of these eligibility criteria and the Priority Rating System developed around them, it may be
argued that an early success of the LASII program was its prioritization of allocation of available funds
towards small, under-resourced, and/or disadvantaged communities and towards addressing
stormwater-related water quality and/or quantity issues that directly benefit those communities.
In agreement with one of the Blueprint's main objectives, aligning with and supporting existing
programs in the state that work in flood resilience, it is recommended that the Blueprint adopt a
similar method to that of LASII to identify stormwater management program funding gaps and
allocate resources to fill those gaps in small, under-resourced communities. An extension of the LASII
program -or re-envisioning of LASII into a similarly structured funding program specifically framed
around the goals of the Flood Resiliency Blueprint-would provide a vehicle for federal and/or state
investments to implement some of this report's recommendations on a broader scale that prioritizes
under-resourced and underserved municipalities of the state.
2.1.5 Recommendation 5: Technical Advisory Group (TAG) Request to
Develop a Centralized State Funding Site
Previous tasks included commentary from TAGs requesting a central funding site for easy access,
navigation, and resources. The recommendations include the following:
Develop a central state funding page.
Consider accessibility requirements for site login and navigation.
Use a singular point of reference for all funding sources.
Connect to federal and state databases.
Develop a simplified single-page printout with funding data for the community.
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2.2 Planning, Data, and Maintenance Recommendations
2.2.1 Recommendation 6: Develop Planning Support
The first step in developing a stormwater maintenance program or considering modifications to an
existing program because of significant investments in resilience like the Blueprint is determining
what to include, which requires state assistance and funding. Developing state-level, basin-specific
stormwater programs to address the local communities' everyday needs would establish a basis for
the community as a starting point that can then be used to build an individual stormwater program or
a regional group of local stormwater programs that have common interests and a desire to
collaborate. The state-level plans should center on basin-wide issues. It is recommended that the
state basin-specific plan be developed and funded by the state so that individual communities are not
burdened with funding plans that stretch across the basin.
The communities can use the information developed in the plans to determine which state funding
and other opportunities to pursue by referencing the basin program requirements and regulations. In
addition, it is recommended that:
Assistance will be provided to local community stakeholders through public input sessions.
Funding should consider the community members most affected by the conditions and ensure
they are willing and able to support the program.
Include stakeholders such as industry experts for the area as part of the local community
stakeholders to ensure community connectivity and insight.
Assist with details on population, socioeconomic patterns, and other data about urban growth
and development combined with community values.
NCDEQ, in collaboration with its partners, develops a funding guidance document as part of the
planning process for large-scale improvements, repairs, or expansions to the stormwater systems.
Multiple stakeholders throughout Phases I and II of the Blueprint identified the planning-related
challenge of implementing flood-resilient stormwater management programs due to the need for in-
house staff with technical expertise and capacity to plan for, implement, and maintain these actions
effectively. To address this challenge, it is recommended that the Blueprint offer to financially support
staff members from organizations that have been awarded funds through the Blueprint for a flood-
resilient stormwater management activity in completing a stormwater management-related
professional certification/training program. Several relevant certification and training options are
offered statewide, including, but not limited to, those depicted in Table 6 .
Under ideal circumstances, the Blueprint would offer to cover the registration costs, in whole or in
part, for a pre-approved certification or training course for at least one staff member from each
organization awarded funding for stormwater management actions through the Blueprint. However,
given the vast array of funding objectives and current financial resources dedicated to the initial
round of Blueprint projects, it is recommended that the Blueprint support at least one member of
interested regional organizations, such as council of governments, river basin associations, etc., in
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completing a novel stormwater management certification or training course and, if applicable in the
given timeframe, one staff member from each interested regional organization in achieving a
recertification. The knowledge and skills gained through this training can be shared and applied
through those organizations' regional activities, which often involve multiple jurisdictions.
2.2.2 Recommendation 7: Develop Data Management Support
Develop a community database for resource management which will allow interdependent
organizations of the state, county, and other municipal jurisdictions to coordinate, communicate, and
support maintenance activities not only within their community but across boundaries (e.g., regional,
basin, municipal, state, etc.) where upstream and downstream conditions are addressed by multiple
participants with responsible, systematic, and transparent approaches. Recommended actions
include the following:
Provide a portal access point for both data download and upload.
Require data updates based on a minimum frequency determined by type of infrastructure, such
as stormwater control measures, stormwater drainage networks, and structural reports on dams,
walls, and bridges.
As a grant provision, require supplemental reports and updates after projects are completed with
state or federal funding.
Require supplemental data for community construction activities, including digital as-builts with
Finished Floor Elevations, mapped floodplains, stormwater retrofit project data including nature-
based solutions, engineered stormwater control devices, and transportation infrastructure
changes that occur, such as bridge, channel, or culvert improvements.
Set a standard format for updating data.
"Retrofits of existing SCMs can take the form of either conversions or enhancements.
Examples of conversions include converting a dry detention basin to a wet pond or
wetland or converting a small pond to a bioretention area or pocket wetland. Examples of
enhancements include enlarging the size of an SCM, adding floating wetlands to a wet
pond, or directing additional runoff from impervious surfaces to an adequately sized
existing SCM."1
Stagger the schedule of updating the basin plans so that significant updates can be staggered to
reduce staff burden where reviews are required.
Further, schedule potential funding assistance on the same schedule with database updates to
provide the community with the option to either:
Request funding support, or
Request the state complete the updates (i.e., contract with consultants to complete the data
updates on behalf of the communities).
1 https://www.deq.nc.gov/energy-mineral-and-land-resources/stormwater/bmp-manual/e-3-retrofits/download
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2.2.3 Recommendation 8: Develop Maintenance Document Support
Develop or assemble an existing list of policies, inspection requirements, and procedures for use in
the individual community operations and maintenance manuals for the stormwater programs (and
subsequent ordinance and municipal code modifications) that address SC Ms available to the
community in reference to system constraints and community values. NCDEQ currently hosts
inspection forms and webinars for wet ponds, bioretention cells, infiltration systems, and stormwater
wetlands. However, these resources should be expanded to include other management strategies,
such as maintaining and enhancing floodplain buyout properties to improve water quality. For all
strategies, include items and practices such as:
Inspection recommendations for drainage systems, structures, and stormwater control measures
(reference regulatory manuals).
Minimum Inspection report data to be provided to the state and how often the inspections should
occur (see Table 12).
Recommendations for findings, such as replacement, stabilization potential, resources, etc.
Monitoring and maintenance (asset management) plan requirements at the 30% design stage to
maximize stormwater projects' function, service life, and cost-effectiveness.
Existing NCDEQ-funded SCM monitoring and maintenance reporting requirements should be
reviewed alongside a study published in 2017 by the American Society of Civil Engineers (Clary and
Piza 2017). The study "Cost of Maintaining Green Infrastructure" presents recommendations for
specific reporting requirements that would support establishing a national SCM database. While at
the national scale, the study's results still apply to the Blueprint, which will support flood resilient
SCM projects statewide. Recommended reporting requirements for best management practice (BMP)
facility information, maintenance event records for facilities, and maintenance activity records can be
found in Table 13, Table 14, and Table 15 of the Appendix.
2.2.4 Recommendation 9: Support the Development of Regional
Stormwater Utilities and Partnerships
The Blueprint can support the development of regional stormwater utilities in the state by facilitating
conversations between communities during the planning process and allocating funding to support
regionalization. Regional stormwater utilities are governmental or quasi-governmental entities
responsible for managing stormwater runoff across multiple jurisdictions within a defined region.
These utilities are typically tasked with planning, constructing, operating, and maintaining
stormwater infrastructure to reduce flooding, improve water quality, and comply with environmental
regulations. Regionalization can have multiple benefits for participating communities, including:
Leadership and policy structure for regulatory compliance
Shared resources such as equipment and technical skills
Common public education programs
Subtask 3.15: Recommendations for Developing and Maintaining Local Stormwater Management
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North Carolina Flood Resiliency Blueprint
Consistent design requirements and post-construction practices specific to the needs of the
watershed.
Several regional entities already offer stormwater management-related services in North Carolina.
These include river basin associations (RBAs), a collaborative organization encompassing multiple
stakeholders, including local governments, non-profit organizations, businesses, and other entities
within a specific river basin. These associations are dedicated to the sustainable management and
protection of water resources within their respective river basins. RBA activities often include pooling
financial, physical, and technical resources, stakeholder and public engagement, regional data
collection and planning, and assisting communities with legal and regulatory compliance. Examples
of RBAs in North Carolina include, but are not limited to, the Upper Neuse RBA, Lower Neuse RBA,
Yadkin-Pee Dee RBA, Roanoke River RBA, Tar-Pamlico RBA, etc. (Table 3 ). Similar partnerships
focusing primarily on public awareness and education include the Regional Stormwater Partnership
of the Carolinas, the Piedmont Triad Water Quality Partnership and Stormwater SMART program, and
the Western North Carolina Stormwater Partnership .
It is recommended that the Blueprint support existing partnerships and regional organizations
focused on stormwater management by allocating funding for these entities' regional flood resilient
stormwater management activities. Further, it is recommended that the Blueprint devote resources in
the future to study the legal, financial, and political structures of these regional entities and the level
of services they provide to identify opportunities or areas for improvement as well as garner lessons
learned that could be used to develop material promoting the formation of new regional
partnerships/organizations throughout the state.
Table 3. Regional organizations/partnerships concerned with stormwater management
Organization Source
Upper Neuse RBA https:Uunrba.orgl
Lower Neuse RBA https;Ulnba,netl
Yadkin-Pee Dee RBA https;lLwww,:iadkinpeedee,QrglabQ!.!t-the-assQdatiQn
Roanoke River RBA https;lLwww.rQanQkeriverbasinassQdatiQn,Qrgl
Tar-Pamlico RBA https:Utarpam.orgl
Regional Stormwater Partnership of
https:Uregionalstormwater.orgl
the Carolinas
Piedmont Triad Water Quality https:lLptwqpartnership.wixsite.comlpiedmontwaterqualit:ilptwqp-
Partnership partners
Stormwater SMART program https;lLwww.ptn:;,QrglserviceslregiQnal-planninglstQrmwater-smart
Western North Carolina Stormwater
https;lLwww.wncstQrmwater,Qrgl Partnership
Subtask 3.15: Recommendations for Developing and Maintaining Local Stormwater Management
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North Carolina Flood Resiliency Blueprint
3 References
"2013-2022 Powell Bill Total Average Appropriation." 2022. NCDOT. November 18, 2022.
https://connect.ncdot.gov/municipalities/State-Street-
Aid /Pu blishi ngl mages/Forms/DispForm.aspx?I D= 17 .
City of Raleigh. 2024. "Stormwater Surety Agreement Process I Raleighnc.Gov." City of Raleigh
Stormwater Services . February 19, 2024.
https: /Ira lei gh nc.gov /stormwater /services/sto rmwater-su rety-agreeme nt-process.
Clary, Jane, and Holly Piza. 2017. Cost of Maintaining Green Infrastructure. Reston , Virginia: American
Society of Civil Engineers. https://ascelibrary.org/doi/book/10.1061/9780784414897.
Hunt, William F., Sarah Waickowski, and William G. Lord. 2021. "Maintenance Costs of Stormwater
Control Measures (SCMs) in North Carolina." 491. NC WRRI.
https://www.lib.ncsu.edu/resolver/1840.20/39523.
"NCDEQ Stormwater Design Manual-Part A-7 . SCM Operation & Maintenance." 2018. NCDEQ .
https://www.deq.nc.gov/energy-mineral-and-land-resources/stormwater/bmp-manual/7-
operation-and-maintenance/download .
Sanchez, Melanie. 2023 . "North Carolina Stormwater Fees Report 2023 ." UNC-CH EFC and NCDEQ-
DWR. https:// efc.sog. u nc.ed u/ resource/ north-ca roli na-stormw ater-f ees-report/.
"Stormwater Fees and Fee Structures in North Carolina as of July 2019." 2020. UNC-CH EFC and
NCDEQ-DWR. https://efc.sog.unc.edu/wp-
content/uploads/sites/1172/2021/05/NC2020StormwaterFeeTables.pdf.
US EPA. 2023. "City of Grand Rapids Credit Trading Program." Overviews and Factsheets. National
Pollutant Discharge Elimination System . May 18, 2023. https://www.epa.gov/npdes/city-
grand-rapids-credit-trading-program .
Subtask 3.15: Recommendations for Developing and Maintaining Local Stormwater Management
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North Carolina Flood Resiliency Blueprint
4 Appendix
Table 4. Additional specific maintenance tasks for common NCDEQ-approved SC Ms (Hunt, Waickowski, and
Lord 2021)
SCM Description Maintenance Tasks Specific to SCM
Bioretention
Depression filled with sandy media and Vegetation pruning and replacement; tree
cell
plants designed to store temporarily and stake/wire removal; flush out underdrain
filter runoff system; mulch replacement; annual soil tests
Depression is designed to capture and
Algae, cattail, phragmites, and other invasive
Wet pond slowly release runoff over a 2-to 5-day vegetation removal; remove trees and weeds
period.
from floating wetland islands; restoring
floating wetland island cables; revegetation
Shallow, vegetation-filled depression
Stormwater designed to capture and slowly release
Algae, cattail, phragmites, and other invasive
runoff over a 2-to 5-day period, store runoff
wetland in shallow pools supporting emergent and vegetation removal; revegetation
riparian vegetation
Vacuum or sweep surface; bag grass
Permeable
Pavement that captures runoff through clippings or direct away from the surface;
voids in the surface and filters runoff weed removal; annual infiltration testing;
pavement
through the underlying aggregate base observation well inspection; surface repair;
flush out underdrain system
Sand filter
Surface or subsurface device that percolates Sweep or vacuum adjacent pavement; flush
runoff through a sand media out underdrain system; replace sand media
Rainwater Collection device storing rainwater for later
Inspect and repair all leaks; clean gutters;
unclog screens and filters; inspect pump;
harvesting use
remove algae; mosquito abatement
Level
Unclog and repair flow splitter device; mow
spreader-fl lter
Exposed buried concrete footer and unclog blind swale; repair or replace
immediately upstream of vegetated area concrete lip; repair erosion and remove
strip
\sediment in filter strip
Unclog gutter system; remove sediment and
Disconnected Practice of directing runoff from built-upon repair erosion in the vegetated area; remove
impervious areas to properly sized, sloped, and trees or shrubs in the vegetated area; remove
surface vegetated pervious surfaces obstructions at the interface of impervious
and vegetated area
Contech
Storm Filter® Proprietary device designed to capture
Mosquito abatement; vacuuming; rinse
(proprietary runoff and slowly release via an outlet
underground structure
chambers; install fresh cartridge(s)
SCM)
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SCM Description Maintenance Tasks Specific to SCM
ADS
BayFilter™
(proprietary
underground
SCM)
Proprietary device designed to capture
runoff and slowly release via an outlet
structure
Mosquito abatement; vacuuming; rinse
chambers; install fresh cartridge(s)
Table 5. Cost, community & environmental issues for SC Ms (NCDEQ 2018)
Construction Maintenance Safety Community Wildlife
SCM
Cost Level Concerns Acceptance Habitat
Bioretention Med-High Med-High N High High
Stormwater Wetland Med Med y Med High
Wet Pond Med Med y Med Med
Sand Filter High High N Med Low
Permeable Pavement Med-High High N High N/A
Infiltration Device Med Med N Med-High Low
Filter Strip Low Low N High Med
Treatment Swale Low Low N High Low
Dry Pond Med Med y Low Low
Rooftop Runoff System Med-High High N High Med
Table 6. NC-based stormwater management certifications and training
Resource Organization Cost (2024) Description
Time requirements: five days
Surface Water Required to make a legal
Identification NC DWR& NC determination of stream origins and
Training& State University
Regular ($765) identify surface waters subject to
Certification buffer rules enacted by the NC
Environmental Management
Commission
Level I -Inspector /Installer
Level 1-11 ($200) Time requirements: online
NC Department of
NCDOT Employee exam (24/7)
Level 1-111 Erosion & Level Ill ($175) Level 2 -Site Management
Sediment Control Transportation &
Regular Level Ill Time requirements: online NC State
Certification ($235) exam (24/7) University
NCDOT Employee Level 3 -Control Plans
Level 1111 ($175) Time requirements: one
day
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Resource Organization Cost (2024) Description
Time requirements: one day
Topics include phasing of
Non-Certification construction, inspection of
Stormwater SCM
NC Department of
Participants materials upon delivery, a
Construction
Energy, Mineral,
($150) multitude of proper construction
and Land practices, and field testing and Inspection
Resources & NC Certification
verification to ensure green Certification
State University Participants
infrastructure and Low Impact ($190)
Design practices are properly
constructed and function as they
are designed
Time requirements: One full day
and one¾ day
NC Department of
Regular ($410) NC communities may either require
Stormwater SCM
Energy, Mineral, Government/Non-or recommend the certification of
Inspection &
and Land profit/Education people who maintain and/or
Maintenance ($350) inspect stormwater management Resources & NC
Certification
State University Virtual ($260) practices. The NC Dept. of Energy,
Mineral and Land Resources
endorses this certification but does
not require it.
Minimum Design Criteria for
Stormwater Designs
Rain Gardens
Various Action Various state Swales, Bio-Swales, and
Specific Workshops agencies & NC Regenerative Stormwater
& Certifications State University Conveyance
Coastal Region Stormwater
Management
Stream Bank Repair, etc.
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Table 7. Stormwater wetlands routine maintenance costs and characteristics in North Carolina 201 8 (Hunt,
Waickowski, and Lord 2021)
Parameter Mean Median Range
Age (yr.) 14 15 10 to 18
Typical footprint (acres) 0.4 0.5 0.25 to 0.50
Maintenance frequency Monthly
Time spent on tasks (hr.) 2 2 lto2
Number of employees
2 2 lto4
maintaining SCM
Mean
(Inflation Adjusted -2023}
*Routine costs without
mowing($/acre) 8,150 9,200 4,600 to 9,600 $10,134 per acre
*Routine costs with
mowing ($/acre)
10 ,950 11 ,600 5,400 to 15 ,200 $13,616 per acre
Table 8. Bioretention cells routine maintenance costs and characteristics in North Carolina 2018 (Hunt,
Waickowski , and Lord 2021)
Parameter Mean Median Range
Age (yr.) 14 15 10 to 15
Typical footprint (acre s) 0.17 0.13 0.05 to 0.25
Maintenance frequency Monthly 8 to 21 per yr.
Time spent on tasks-mulched
1 1 0.25 to 3 (hr.)
Number of employees
3 2 lto9
maintaining SCM-mulched
Routine costs without mowing -
11,867 12,000 9,200 to 14,400
mulched ($/acre)
Routine costs with mowing -
12,400 12,000 12 ,000 to 14,400
mulched ($/acre)
Time spent on tasks-grassed
1 1 1 to 1.5 (hr.)
Number of employees
maintaining SCM-grassed
3 2 lto9
Routine costs without mowing -
13,467 12,000 9,200 to 19 ,200
grassed ($/acre)
Routine costs with mowing -
15,600 12,000 10 ,800 to 24,000
grassed ($/acre)
Mean
(Inflation Adjusted -
2023)
$14,756 per acre
$15,419 per acre
Mean
(Inflation Adjusted -
2023)
$16,746 per acre
$19,398 per acre
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Table 9. Wet ponds routine maintenance costs and characteristics in North Carolina 2018 (Hunt, Waickowski,
and Lord 2021)
Parameter Mean Median Range
Age (yr.)
Typical footprint (acres)
Maintenance frequency
Time spent on tasks (hr.)
Number of employees maintaining
SCM
Routine costs without mowing
($/acre)
Routine costs with mowing ($/acre)
16
0.5
Month[
y
2
3
6,360
9,440
16 10 to 28
0.5 0.25 to 0.75
8 to 21 per yr.
1 0.25 to 6
2 lto9
4,600 4,000 to 9,600
8,800 5,400 to 15,200
Mean
(Inflation Adjusted -
2023)
$7,909 per acre
$11,738 per acre
Table 10. Dry ponds routine maintenance cost characteristics in North Carolina 2018 (Hunt, Waickowski, and
Lord 2021)
Parameter Mean Median Range
Age (yr.)
Typical footprint (acres)
Maintenance frequency
Time spent on tasks (hr.)
Number of employees maintaining
SCM
Routine costs without mowing
($/acre)
Routine costs with mowingb ($/acre)
14
0.42
Month[
y
1
3
6,920
11,320
15 10 to 18
0.5 0.25 to 0.50
4 to 21 per yr.
1 0.17 to 2
4 lto9
6,000 5,400 to 9,600
10,400 6,600 to 18,000
Mean
(Inflation Adjusted -
2023)
$8,605 per acre
$14,076 per acre
Subtask 3.15: Recommendations for Developing and Maintaining Local Stormwater Management
Programs 24
North Carolina Flood Resiliency Blueprint
Table 11. Sand filters routine maintenance costs and characteristics in North Carolina 2018 (Hunt, Waickowski,
and Lord 2021)
Parameter Mean Median Range
Age-above ground (yr.)
Typical footprint-above ground
(acre)
Maintenance frequency-above
ground
Time spent on tasks-above ground
(hr.)
Number of employees maintaining
SCM-above-ground
Routine costs without mowing-
above ground ($/acre)
Routine costs with mowing -above
ground ($/acre)
Age-underground (yr.)
Typical footprint-underground
(acre)
Maintenance frequency-
underground
Time spent on tasks-underground
(hr.)
Number of employees maintaining
SCM-underground
Routine costs without mowing -
underground, residential ($/acre)
Routine costs without mowing -
underground, commercial ($/acre)
10
0.22
Monthly
1
2
13,281
16,875
10
0.2
Quarterly
1
4
73,086
91,207
10 5 to 12
0.22 0.02 to 0.33
4 to 21 per yr.
1 0.25 to 1.50
2 lto9
14,262 5,400 to 78,407
16,951 9,600 to 24,000
9 8 to 10
0.2 0.01 to 0.50
4 to 21 per yr.
1 0.25 to 1.5
4 3to4
74,407 4,000 to 145,200
78,407 4,000 to 223,028
Mean
(Inflation Adjusted -
2023}
$16,515 per acre
$20,984 per acre
Mean
(Inflation Adjusted -
2023}
$90,881 per acre
$113,414 per acre
Subtask 3.15: Recommendations for Developing and Maintaining Local Stormwater Management
Programs 25
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•
•
•
•
•
•
•
•
•
•
•
North Carolina Flood Resiliency Blueprint
Table 12. NC Stormwater Design Manual required inspection frequency for SC Ms (NCDEQ 2018)
Frequency SCM
Monthly and within 24 hours after every water quality storm
(greater than 1.5 inches in Coastal Counties and greater than 1.0
inches elsewhere)
Quarterly and within 24 hours after every water quality storm
(greater than 1.5 inches in Coastal Counties and greater than 1.0
inches elsewhere)
Stormwater Wetlands
Wet Detention Basins
Bioretention Cells
Level Spreaders
Infiltration Devices
Sand Filters
Extended Dry Detention Basins
Permeable Pavement
Rooftop Runoff Management
Filter Strips*
Grassed Swales*
Restored Riparian Buffers*
* Although these devices require quarterly inspection, mowing will usually occur more frequently during the
growing season.
Subtask 3.15: Recommendations for Developing and Maintaining Local Stormwater Management
Programs 26
North Carolina Flood Resiliency Blueprint
Table 13. Reporting data for stormwater maintenance costs: best management practice (BMP) facility
information (facility information is provided in one record and then related to multiple maintenance records in
Table 14) (Clary and Piza 2017)
Parameter Description/Picklist
Asset ID Use the number in the asset management system if applicable.
Facility Type Individual, cluster, other
Decimal Latitude
GPS centroid/geolocated address-enables mapping of
Decimal Longitude
BMP Name General facility name
BMPType
Picklist: bioretention, grass swale , grass buffer, tree planter, permeable
pavement, composite (treatment train), etc.
City Enables geographic comparison of records locally and nationally
State Enables geographic comparison of records nationally
Date I nsta lied Enables tracking of maintenance cost over time
Tributary Land Area (ac.) Size of drainage area to facility
Imperviousness(%) Percent impervious area
Land Use(s) Picklist
Snow/Ice Management Picklist
Qualitative Site Loading Intensity
High, moderate , low (i.e., is the site heavily used/dirty, or is it lightly
used/clean)
Tributary Land Area
Include other pertinent characteristics affecting maintenance.
Description/Conditions
Treatment Volume (cf.) Provides treatment volume, e.g., Water Quality Capture Volume
Surface Area Provides information on the footprint of the facility that is maintained
Facility Sizing Picklist: standard , oversized , undersized (e.g., not to design standards)
Media Type Picklist: In situ soils , engineered media, not applicable
Vegetation Type
Picklist: highly manicured, moderately manicured, low maintenance,
native grasses, turf, wetland vegetation , not applicable
Pretreatment Features
Describe pretreatment features that facilitate ease of maintenance, e.g.,
sediment forebay.
Inlet Feature
Describe inlet(s), including features affecting maintenance.
requirements
Facility Ownership Picklist: public , private, private-easement, private-HOA, other
Public Visibility Picklist: high, medium, low
Monitoring Data? Yes/no/unknown (flag to trigger tie-in to BMP Database)
Comments
Additional description of facility that influences maintenance costs, if
needed.
Subtask 3.15: Recommendations for Developing and Maintaining Local Stormwater Management
Programs 27
North Carolina Flood Resiliency Blueprint
Table 14. Reporting data stormwater maintenance costs : maintenance event records for the facility (multiple
event records over time, linked to the facility information in Table 13 ) (Clary and Piza 2017)
Parameter Description/Picklist
Asset ID Use the number in the asset management system if applicable.
Maintenance ID Maintenance Record number (auto-populated)
Event Record Type Annual summary, individual event, other
Work Order ID Work order ID used in the asset management system (if applicable)
Work Oder Description
Individual facility visits, multiple facility visits, individual facility-multiple
visits, multiple facility-multiple visits, unknown
Mobilization Type Picklist: multiple facilities, single facility
Facility Stage at Time of Picklist: establishment, mature, post-mature (overgrown)
Maintenance
Facility Performance Status Normal, failing, unknown.
General Climate Condition Picklist: normal , wet, dry
Maintenance Type Picklist: Inspection only, routine, restoration/reactive, rehabilitation, other
Maintenance Entity Picklist: contractor, municipal, volunteer, combination
Maintenance Date Enables normalization of cost data over time and documents frequency
Describe activities conducted or use the additional detailed checklist in
Maintenance Narrative
Table 15
Disposal Type Solid waste, hazardous waste, storage for bulk disposal, unknown
Irrigation Irrigation required; no irrigation
Total Cost($) Total overall cost
Cost Type Picklist: flat fee, time & materials
Labor Cost($) Total labor cost
Labor Time (min.) Time required to complete maintenance/site visit
Labor Rate ($/hr.) Hourly labor rate
Materials Description Plants, mulch, media, hardscape , chipping materials, etc.
Materials Cost($) Cost of materials
Equipment Description Equipment used, e.g ., vacuum sweeper, shovel, backhoe
Equipment Ownership Own, rent , contractor
Equipment Cost Basis Describe the basis for allocating the cost of owned equipment.
Equipment Cost($) Rental cost or owner cost
Disposal Cost($) Cost of sediment/materials disposal, if applicable
Admin./Overhead Cost($)
The administrative cost of scheduling/tracking maintenance is not reflected
in the labor cost.
Other Cost Additional costs for traffic management or other costs not included above
Comments Additional comments that identify unusual aspects of maintenance event
Subtask 3.15: Recommendations for Developing and Maintaining Local Stormwater Management
Programs 28
North Carolina Flood Resiliency Blueprint
Table 15. Reporting data for stormwater maintenance costs: maintenance activity records (activities conducted
during maintenance events defined in Table 13) (Clary and Piza 2017)
Parameter Description/Picklist
Asset ID
Use the number in the asset management system if
applicable.
Maintenance Record ID Maintenance Event ID (from Activity Table)
Sediment removal Y/N
Weeding/thinning/vegetation removal Y/N
Plant replacement/seeding/sodding Y/N
Supplemental Irrigation Y/N
Mowing Y/N
Fertilization Y/N
Pruning Y/N
Trash/debris/leaf removal Y/N
Erosion repair Y/N
Mulch replacement Y/N
Inlet cleaning Y/N
Outlet cleaning Y/N
Vacuum/sweep surface Y/N
Jet-Vac/subsurface vacuum Y/N
Rechip permeable pavement Y/N
Replace media Y/N
Structural repair Y/N
Clear pipes Y/N
Mosquito control Y/N
Algae control Y/N
Rodent management/address animal damage Y/N
Other activity/comment Describe other activities/ provide comments.
Subtask 3.15: Recommendations for Developing and Maintaining Local Stormwater Management
Programs 29