Inspection and Maintenance of Inspection and Maintenance of Stormwater Control Measures:Stormwater Control Measures:

Helping Protect GreensboroHelping Protect Greensboro’’s Water Quality s Water Quality and Waterand Water--SupplySupply

NC APWA Stormwater Management NC APWA Stormwater Management ConferenceConference--September 16, 2013September 16, 2013

Program BackgroundProgram Background

Privately owned Privately owned stormwaterstormwater treatment devices treatment devices ((SCMsSCMs) are required throughout Greensboro) are required throughout Greensboro’’s s jurisdictional limit due to either watershed waterjurisdictional limit due to either watershed water-- supply and/or Phase II regulations.supply and/or Phase II regulations.

Watershed regulations began in mid 1980Watershed regulations began in mid 1980’’s. s. Formal inspection program didnFormal inspection program didn’’t begin until t begin until 1998. Most of the 1998. Most of the SCMsSCMs had not been maintained had not been maintained since originally installed. since originally installed.

A significant educational effort along with A significant educational effort along with persistent inspection and enforcement was persistent inspection and enforcement was necessary to complete first full round of necessary to complete first full round of inspections and necessary maintenance.inspections and necessary maintenance.

Program BackgroundProgram Background

The City of Greensboro's waterThe City of Greensboro's water--supply watershed and supply watershed and stormwaterstormwater management ordinances (Ch. 30) require management ordinances (Ch. 30) require property property owner(sowner(s) to meet certain maintenance ) to meet certain maintenance requirements for constructed requirements for constructed SCMsSCMs. .

Since 1998, Since 1998, StormwaterStormwater Management Division staff Management Division staff have been conducting these inspections to ensure have been conducting these inspections to ensure privately owned privately owned SCMsSCMs are being maintained and are being maintained and functioning properly.functioning properly.

The City of Greensboro currently inspects The City of Greensboro currently inspects approximately 600 approximately 600 SCMsSCMs! !

Properly designed, built, and maintained Properly designed, built, and maintained SCMsSCMs should ideally be an asset to a property, not a should ideally be an asset to a property, not a liabilityliability……Right?Right?

Asset or liability to property owner?

SCM Locations in GreensboroSCM Locations in Greensboro

Local Permit IssuanceLocal Permit Issuance

Group Development, Commercial, & Subdivision Group Development, Commercial, & Subdivision Plans are reviewed by CityPlans are reviewed by City’’s Technical Review s Technical Review Committee (TRC).Committee (TRC).

StormwaterStormwater Engineer reviews to make sure plan Engineer reviews to make sure plan meets Post construction SWM & LDO requirements.meets Post construction SWM & LDO requirements.

Issuance of building or grading permit contingent on Issuance of building or grading permit contingent on TRC approval.TRC approval.

After plan approval by TRC, a preAfter plan approval by TRC, a pre--construction construction meeting is set by the Engineering & Inspections meeting is set by the Engineering & Inspections DepartmentDepartment

Local Permit IssuanceLocal Permit Issuance

Design engineers are involved during construction Design engineers are involved during construction phase with City performing site inspections.phase with City performing site inspections.

Final inspection of SCM performed by Final inspection of SCM performed by StormwaterStormwater Operations Section. Operations Section.

Design Engineer submits final certification and asDesign Engineer submits final certification and as-- builtsbuilts..

City inspects and accepts SCM once standards are City inspects and accepts SCM once standards are met. Then proceeds with plating and CO issuance.met. Then proceeds with plating and CO issuance.

Ownership of SCM transfers to HOA or property Ownership of SCM transfers to HOA or property ownerowner……Maintenance Inspections Start!!!!Maintenance Inspections Start!!!!

Where to start first?Establish inspection process for efficient identification of any problems that may affect the safety or functional efficiency of the SCMs.

1. Development of inspection and documentation procedures

• Dam Safety

• Inlets and Outlets

• Vegetation

• Sedimentation

2. Database to manage inspection history

3. Enforcement procedures

Development of inspection and documentation procedures

SCM Inspection ProcessSCM Inspection Process1.1. Research and investigate ownership information. Research and investigate ownership information.

Contact information, especially for Contact information, especially for HOAHOA’’ss, tends to , tends to change often.change often.

2.2. Complete onsite inspection and fill out inspection Complete onsite inspection and fill out inspection form.form.

3.3. Mail copy of inspection form to Mail copy of inspection form to owner(sowner(s). If ). If maintenance is needed, allow maintenance is needed, allow 90 days90 days to complete to complete maintenance.maintenance.

4.4. If work not complete in 90 days, allow an additional If work not complete in 90 days, allow an additional 30 days30 days to complete maintenance.to complete maintenance.

5.5. If work not complete in 120 days, If work not complete in 120 days, City may complete City may complete the maintenance and assess the the maintenance and assess the owner(sowner(s) for costs ) for costs and damages incurred!and damages incurred!

Inspection list created Ownership and site plan researchOn-site inspection

Follow-up phone callsand technical assistance

throughout 90 days

Re-inspection

Phone call to informcurrent owner of annual inspecition

(if ownership has NOT changed)

Are recommended/requireditems complete??

If required itemsNOT complete

Inspection report sent

- If no action needed, send regular mail & close out - If recommended items, send regular mail - If required items, send certified mail along with formal letter, attachment #3

Follow up phone calls

Supervisor andManagers

SEEK ASSISTANCE& pursue enforcement

Supervisor receivesinspection list

Education letter sentAttachment #1

(only if ownership has changed)

January 2007

S M T W T F S

1 2 3 4 5 6

7 8 9 10 11 12 13

14 15 16 17 18 19 20

21 22 23 24 25 26 27

28 29 30 31

90 days

final letter & close out

(if required items complete or if recommended itemscomplete or uncomplete)

send certified NOV

(and coordinatewith Supervisor)

January 2007

S M T W T F S

1 2 3 4 5 6

7 8 9 10 11 12 13

14 15 16 17 18 19 20

21 22 23 24 25 26 27

28 29 30 31

30 days

send 2ndcertified NOV

(and coordinatewith Supervisor)

January 2007

S M T W T F S

1 2 3 4 5 6

7 8 9 10 11 12 13

14 15 16 17 18 19 20

21 22 23 24 25 26 27

28 29 30 31

14 days

SCM Inspection Program Work Flow Chart

Development Development of of

standardized standardized inspection inspection checklistschecklists

What do we inspect, and what What do we inspect, and what problems do we look for?problems do we look for?

Dam Safety Dam Safety –– Leakage and SeepageLeakage and Seepage

Inspect downstream side of earthen dam for Inspect downstream side of earthen dam for evidence of significant leakage or seepage evidence of significant leakage or seepage (saturated soil, sediment deposits, flowing water, (saturated soil, sediment deposits, flowing water, etc).etc).

Inspect backside of reinforced concrete dam for Inspect backside of reinforced concrete dam for cracks, leaks, or displacement (noticeable leaning cracks, leaks, or displacement (noticeable leaning or bulging).or bulging).

If evidence is observed, owner should seek If evidence is observed, owner should seek assistance from a professional engineer.assistance from a professional engineer.

Dam Safety Dam Safety –– Dam material problemsDam material problems

On earthen dam, look for evidence of pronounced On earthen dam, look for evidence of pronounced cracks on the embankment surface.cracks on the embankment surface.

Perpendicular cracks may indicate differential Perpendicular cracks may indicate differential settling of the dam.settling of the dam.

Parallel cracks may be due to improper Parallel cracks may be due to improper compaction or shrinkage of the clay.compaction or shrinkage of the clay.

Depressions, sink holes, or animal burrows.Depressions, sink holes, or animal burrows.

If evidence is observed, owner should seek If evidence is observed, owner should seek assistance from a professional engineer.assistance from a professional engineer.

Dam Safety Dam Safety –– Vegetative growthVegetative growth

This is one of the most common problems we see!This is one of the most common problems we see!

The earthen dam should be wellThe earthen dam should be well--vegetated, but grass should vegetated, but grass should be maintained at a height of less than 9be maintained at a height of less than 9””..

Trees, saplings, and other woody vegetation are not permitted Trees, saplings, and other woody vegetation are not permitted on any part of the earthen dam. Large roots systems can on any part of the earthen dam. Large roots systems can jeopardize the integrity of the dam and provide pathways for jeopardize the integrity of the dam and provide pathways for seepage.seepage.

Thick, tall vegetation (Thick, tall vegetation (LespedezaLespedeza, briars, etc.) can also , briars, etc.) can also provide cover and hide the activity of burrowing animals provide cover and hide the activity of burrowing animals (muskrats and groundhogs). The network of burrows can (muskrats and groundhogs). The network of burrows can weaken the dam and also provide pathways for seepage and weaken the dam and also provide pathways for seepage and future dam failure.future dam failure.

General ErosionGeneral Erosion

The dam, side slopes, inlet and outlet areas, The dam, side slopes, inlet and outlet areas, as well as localized watershed draining to as well as localized watershed draining to the pond should remain vegetated and the pond should remain vegetated and stable in order to prevent erosion and stable in order to prevent erosion and excessive sedimentation.excessive sedimentation.

Maintain or enforce S&EC measures Maintain or enforce S&EC measures within drainage areawithin drainage area

Periodic sweeping of streets and parking Periodic sweeping of streets and parking lots can also reduce amount of sediment lots can also reduce amount of sediment and other debris entering the pond.and other debris entering the pond.

EmbankmentsEmbankments

Pond embankments should be kept wellPond embankments should be kept well-- vegetated to prevent erosion. Grass on the vegetated to prevent erosion. Grass on the pond embankments should be well maintained pond embankments should be well maintained (mowed at least once a year).(mowed at least once a year).

Small channels and gullies should be filled, Small channels and gullies should be filled, compacted, and seeded.compacted, and seeded.

Landscaped trees, shrubs, and flowers are Landscaped trees, shrubs, and flowers are acceptable on embankment areas (no trees on acceptable on embankment areas (no trees on the earthen dam!).the earthen dam!).

Inlet and Outlet Pipe AreasInlet and Outlet Pipe Areas

Structural integrity of inlet and outlet structures should be Structural integrity of inlet and outlet structures should be intact and functional.intact and functional.

Inlet and outlet pipe areas should remain clear of Inlet and outlet pipe areas should remain clear of obstructions (sediment buildobstructions (sediment build--up, trash, and debris) and up, trash, and debris) and overgrown vegetation.overgrown vegetation.

Gullies or eroded areas should be repaired with Gullies or eroded areas should be repaired with compacted soil, compacted soil, geotextilegeotextile fabric, and ripfabric, and rip--rap.rap.

Maintain access to the outlet pipe, and discharge area Maintain access to the outlet pipe, and discharge area should be inspected to make sure it is not should be inspected to make sure it is not ““pipingpiping””..

Water Quality/Low Flow OrificeWater Quality/Low Flow Orifice

The water quality/low flow orifice in the The water quality/low flow orifice in the metal riser or concrete spillway should be metal riser or concrete spillway should be protected with a trash guard.protected with a trash guard.

The orifice should be routinely inspected The orifice should be routinely inspected to make sure it is not clogged (sticks, to make sure it is not clogged (sticks, bottle caps, plastic bags, fish, frogs, bottle caps, plastic bags, fish, frogs, algae, etc).algae, etc).

Trash RackTrash Rack

The trash rack on top of the metal riser is The trash rack on top of the metal riser is intended to trap sticks, trash, and other intended to trap sticks, trash, and other debris during highdebris during high--flow events.flow events.

Like the orifice, the trash rack should be Like the orifice, the trash rack should be routinely inspected to make sure it is routinely inspected to make sure it is clear of debris.clear of debris.

Emergency SpillwayEmergency Spillway

Normally constructed as a depression or Normally constructed as a depression or ““notchnotch”” in the earthen dam or in the corner of in the earthen dam or in the corner of the dam area. Typically lined with ripthe dam area. Typically lined with rip--rap.rap.

The emergency spillway should be maintained The emergency spillway should be maintained just like the earthen dam just like the earthen dam –– no woody vegetation, no woody vegetation, and grass should be well maintained (mowed at and grass should be well maintained (mowed at least annually).least annually).

In the event that the emergency spillway is In the event that the emergency spillway is utilized (e.g. during a hurricane), spillway must utilized (e.g. during a hurricane), spillway must not be blocked or impeded!not be blocked or impeded!

Sediment AccumulationSediment Accumulation

Removal of builtRemoval of built--up sediment is eventually up sediment is eventually going to be necessary for every detention pond. going to be necessary for every detention pond. START BUDGETING FOR IT NOW!!!!START BUDGETING FOR IT NOW!!!!

Maintain clear access easements to the Maintain clear access easements to the pond.pond.

Set aside an onsite disposal area for dredge Set aside an onsite disposal area for dredge material. Land application is allowed and material. Land application is allowed and saves on hauling and disposal costs.saves on hauling and disposal costs.

Routinely inspect sediment levels in pond, Routinely inspect sediment levels in pond, make observations of sediment plumes, and make observations of sediment plumes, and compare to allowable sediment storage per compare to allowable sediment storage per engineering design plans.engineering design plans.

Other General MaintenanceOther General Maintenance

RoutineRoutine trash picktrash pick--up in and around pond.up in and around pond.

Stock pond with Stock pond with GambusiaGambusia ((mosquitofishmosquitofish). County ). County Division of Environmental Health may assist. Division of Environmental Health may assist.

Manage sediment level and vegetation within pond Manage sediment level and vegetation within pond or SCM. Excessive vegetation has been shown to or SCM. Excessive vegetation has been shown to provide cover and habitat for mosquito populations. provide cover and habitat for mosquito populations.

Fencing around the pond is solely up to the pond Fencing around the pond is solely up to the pond owner(sowner(s). City of Greensboro does ). City of Greensboro does notnot require require fencing.fencing.

GambusiaGambusia ((mosquitofishmosquitofish))

•• The The mosquitofishmosquitofish only grows to about 1.5only grows to about 1.5”” long, and can survive in hot, long, and can survive in hot, stagnant, lowstagnant, low--oxygen water (like a detention pond).oxygen water (like a detention pond).

•• They are voracious eaters, but feed primarily on mosquito larvThey are voracious eaters, but feed primarily on mosquito larvae and ae and pupa in the water column.pupa in the water column.

What do we do with all the information?

Store ownership and inspection history in both hard copy and a database format.

Document

Document

Document

TELEPHONE CALL LOG

Call To:_______________________ Date:_________________________

Call From:_____________________ Time:_________________________

Comments:_________________________________________________________ __________________________________________________________________ __________________________________________________________________ __________________________________________________________________ __________________________________________________________________ __________________________________________________________________ __________________________________________________________________

Document everything in a hard copy file folder for each facility. Include all letters, pictures, any conversations, voice mails, or emails. Should case ever proceed to enforcement, a detailed history of the City’s effort to date is invaluable!

Enforcement Procedures

1. Was maintenance required or recommended?

2. When required work hasn’t been completed within 90 day timeframe – 1st NOV is issued giving an additional 30 days to complete the required work.

3. If required work still not completed by the additional 30 day deadline, 2nd and final NOV is written stating that the City (or our contractor) can come in at any time and complete the work and bill the property owner.

Note: NOVs are standardized template letters.

Other SCM types:Other SCM types:

BioretentionBioretention AreasAreas

Sand FiltersSand Filters

Approved Proprietary DevicesApproved Proprietary Devices

StormwaterStormwater WetlandsWetlands

Take home lessons:1. Thorough and consistent maintenance inspections are

the key to having SCMs maintained by private property owners.

2. Well maintained SCMs will protect water quality.

3. Poorly maintained SCMs will not protect water quality and will become a problem for the property owner.

4. Owner education is an essential and necessary component for the owner to understand the significance of these structures and how to take care of them.

5. It takes more persistence than originally thought to convince people to spend money on SCM maintenance.

The City feels that in-house inspections of SCM’s ensure maintenance is being done and wq is protected.

Question or Comments?Question or Comments?

Peter.schneider@greensboro-nc.gov (336) 373-2737

www.greensboro-nc.gov/stormwater