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managing stormwater An introduction to maintaining stormwater facilities ~ for private property owners and HOAs

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managing stormwater

An introduction to maintainingstormwater facilities

~ for private property owners and HOAs

The Stormwater Partners of SW Washington and Clark County, Washington

are credited for the original development of this manual titled

Managing Stormwater: An Introduction to Maintaining Stormwater Facilities.

Please contact them if you would like to use their materials by

visiting www.stormwaterpartners.com.

~ 1 ~

contentsSTORMWATER MANAGEMENT

Introduction - rain and stormwater runoff . . . . . . . . . . .

How stormwater facilities work . . . . . . . . . . . . . . . . . . . .

MANAGING PRIVATE STORMWATER FACILITIES

• Who is responsible? . . . . . . . . . . . . . . . . . . . . . . . . . . .

• Do you have a stormwater facility? . . . . . . . . . . . . . . .

• Talking to neighbors . . . . . . . . . . . . . . . . . . . . . . . . . . .

• Cost of maintaining a private stormwater facility . . .

• Guidelines for maintaining private stormwater

facilities, an overview . . . . . . . . . . . . . . . . . . . . . . . . . .

HOW TO RECOGNIZE STORMWATER FACILITIES . . . . . . . . . . .

FACILITIES MAINTENANCE GUIDELINES

Biofiltration

• Swale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

• Filter strip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Ponds

• Detention basin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

• Infiltration basin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

• Retention Pond . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Underground

• Catch basin and manhole . . . . . . . . . . . . . . . . . . . . . . . .

• Drywell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

• Vaults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Stormwater filter, vortex sedimentation vault,

closed detention system

TIPS FOR MANAGING STORMWATER AT HOME . . . . . . . . . . .

MAINTENANCE GUIDELINES FOR BUSINESSES . . . . . . . . . . . .

GLOSSARY OF DEFINITIONS . . . . . . . . . . . . . . . . . . . . . . . . . .

CONTACTS AND RESOURCES . . . . . . . . . . . . . . . . . . . . . . . . . .

WEBSITE: www.wceo.us/pages/stormwater-district.html

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• Rain Garden . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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~ 3 ~

April 2012

The Warren County Engineer’s Office administers

the County’s MS4 permit under the National

Pollutant Discharge Elimination System (NPDES)

commonly known as Phase II. The Warren County

Stormwater District was formed by the Warren

County Commissioners to facilitate the coordination

of this permit for other MS4 entities including the

Townships of Clearcreek, Franklin, Hamilton,

Turtlecreek, and Union and the Villages of Maineville

and South Lebanon. The WCEO’s administration

includes annual reporting, planning, and meeting the

requirements of the permit by collaborating with other

local agencies such as the Warren County Combined

Health District (WCCHD) and the Warren County

Soil and Water Conservation District (WCSWCD).

The goal of the program is to protect the quality of our

streams, lakes, and groundwater. We also partner with

other local agencies to work toward realizing this goal.

See page 27 for their contact information.

Visit www.wceo.us/pages/Stormwater-District.html

~ 4 ~

Hold and reduce water flow

~ 5 ~

HOW STORMWATER FACILITIES WORK

Some facilities are simple and small, such as a bio-filtration swale with mowed grass. Others are com-plex, such as a system of ponds and undergroundstructures. All are designed to capture stormwaterand treat it – usually by collecting it and filteringcontaminants.

Collect and transport stormwaterStormwater systems typically consist of catchbasins and pipes and/or open channels (ditches).They are large enough to handle runoff from infre-quent, large storms. Typical system failures includereduced capacity because of clogged grates or pipesand or ditches blocked with weeds or debris. If thecapacity of the conveyance system is reduced, iso-lated flooding and property damage can occur.

Some facilities detain and slow the flow of storm-water to surface waters. Roads, roofs and otherhard surfaces increase the rate of stormwater run-off into natural streams, potentially causing streamor channel erosion and flooding. Detention facili-ties, such as ponds and underground vaults, store

stormwater management

Rain becomes stormwater runoff when it flowsoff roofs, yards, streets and parking lots and intoour streams, lakes, rivers, wetlands, and ground-water. As runoff washes over these surfaces, itpicks up dirt, pet waste, litter, motor oil and a hostof other pollutants and dumps them into nearbywaterways.

Stormwater runoff is managed by channeling itthrough specially built landscaped and structuralfeatures called stormwater facilities. They removepollutants and slow stormwater flowing into ourwaterways. Both functions are critical to reducethe risk of flooding and protect the health of ourstreams, lakes, wetlands and drinking water.Ponds, inlets, ditches and drains are part of ourcommunity’s stormwater management system.

Although some stormwater treatment facilitiesmight be maintained by your city or county,stormwater facilities often have private owners,including homeowner associations (HOAs), whomust inspect and maintain them. These privatefacilities may serve housing developments, schools,churches, commercial buildings and parking lots.

This guidebook gives an overview of facilitiesyou or your association must maintain, tipson how to maintain and fix them, how to recognizefacilities in your development, and whom to contactwith questions and other resources.

Store and treat runoff

~ 4 ~~ 6 ~

How to know if a facilityis public or privateUnless there is a sign thatsays who owns the facility,there is no quick or univer-sal way to tell if a facility ispublic or private. Generally,ditches or storm drains andpipes within the right of wayare public. Facilities withinprivate properties areoften, but notalways, private.

stormwater for controlled release and help preventdownstrean flooding and erosion.

Detention basins store or retain runoff temporarilywhile it soaks into the ground. This system mimicsnatural processes caused by trees, vegetation andmicrobes that help break down and remove pollut-ants. Retention facilities typically release less storm-water to waterways.

Multiple facility systemsStormwater treatment Best Management Practices(BMPs) refer to multiple approaches to treat andimprove water quality. The most common includeswales and wet or dryponds. More complexsystems include under-ground vaults with car-tridge filters or oil/waterseparators. All thesemethods help removeoils, chemicals, met-als and sediment fromstormwater runoff beforeit is discharged to groundor surface water.

A well-maintained drywell has no debris or standing water. This photo shows water

draining after a rain storm. The holes around the wall allow water to soak into the

ground. See page 19 for more information about drywells.

~ 7 ~

MANAGING PRIVATE STORMWATER

FACILITIES

Who is responsible?In Warren County, public agencies or privateproperty owners are responsible for maintainingstormwater facilities. All facilities, whether pub-lic or private, must meet the same state and localmaintenance requirements for proper control andtreatment of stormwater runoff.

Homes built before the 1980s typically drain toroadside ditches maintained by local government.In newer residential developments, however, oneor more stormwater facilities could be part of theinfrastructure.

Since 1991, local jurisdictions have requiredsome form of stormwater detention a conditionof development. Rules became more rigorous in2003 and now stormwater detention systems mustbe in place when improving or constructing roads,parking lots, buildings and homes.

Do you have a stormwater facility?Check with your homeowners association leader-ship or city or Warren County Soil and Water Dist-rict (WCSWCD) to see if your housing developmenthas such a facility. Commercial and industrial devel-opments also are required to maintain private storm-water facilities.

If you live in a residential development with aprivate facility, your HOA leadership should haveaccess to information about the locations andtypes of facilities serving your property as well asa maintenance plan. Your HOA dues may help payfor private stormwater system maintenance.

If your residential development does not havean HOA, or the HOA has no mention of stormwatermanagement, here’s how to check to see if you haveany stormwater facilities:• Look for this information in the notes on your

recorded plat of your subdivision, which is usu-ally included with the paperwork you received

when closing the purchase of your home. Or, lookin the “Covenants, Conditions, and Restrictions”(CC&Rs) for your subdivision.

• Go to page 9 to see How to recognize stormwa-ter facilities.

• Contact the Soil and Water Conservation District(see page 27 for contact information) to ask an insp-ector to check your housing development.

Talking to NeighborsIn some cases, homeowners don’t realize there arestormwater facilities in their neighborhood. Thesites often look like natural features or may notbe readily visible. You might be surprised to learnthere is a facility in the neighborhood, let alone thathomeowners are responsible for maintaining it.

Informing your neighbors about an existingstormwater system and why it’s important to yourcommunity is critical. Here are some ways to help:• Distribute flyers on stormwater management

to your HOA members.• Post information to your community website.• Put a sign on the facility.• Discuss the issue at your neighborhood

meetings.• Invite a stormwater specialist to give a pre-

sentation to your members and lead a tour of thefacility (see page 27 for contact information).

• Tag friendly reminders near stormdrains. Check with your city or county forpaints, stencils and other supplies to assistneighborhoods,education groupsor other volun-teers. Storm draintags help othersunderstand thatall drains event-ually empty intosurface or groundwater.

The best way to limit big repairs and ensure thatyour facilities are working properly is to followa regular inspection and maintenance plan. Forsmall, simple facilities, such as biofiltration swales,much of the maintenance can be done by neigh-bors or landscaping firms. More complex facilitiesrequire professional maintenance and repair.

You should have a current maintenance plan foryour neighborhood’s stormwater facilities. A planmight be outlined in your HOA’s records or yourCC&Rs. If neither is available, a maintenance planshould be formulated. It should include:• A schedule for routine maintenance.• A record-keeping system for inspections and

maintenance activities.

~ 8 ~

• Show your neighbors pictures and examplesof stormwater management best practices usedin other communities.See www.warrenswcd.com

• Talk about the benefits a well maintained stormwater system provides: more attractiveneighborhoods, higher property value, reducedpotential for flooding and protected streams andhabitats.

Cost of maintaining a private stormwater

facilityIf properly constructed and maintained, residentialstormwater facilities can be relatively inexpensiveto keep in proper working condition. However, ma-jor repairs can require professional assistance andbe much more costly. Nearly all facilities likely willneed some type of major service at some point.

Property owners should set aside money forroutine maintenance as well as the occasions whenoutside expertise or equipment is needed to main-tain, upgrade or repair a system. Costs of maintain-ing a facility will vary depending on the level ofmaintenance needed.

Guidelines for maintaining private

stormwater facilities

• Maintenance standards and procedures (such asmowing grass if higher than 10 inches, no stand-ing water); see www.wceo.us/pages/Stormwater-District.html

• Designated volunteers and/or professionalsresponsible for inspections. Some local agenciesroutinely inspect private facilities; ask for a copyof the inspection report. See page 27 for contactinformation.

• Designated volunteers and/or professionals resp-onsible for maintenance.

Managing your stormwater system requires acombination of simple routine maintenance, suchas raking leaves and mowing and removing grassdebris. A significant amount of the work can bedone by neighbors or those who do your regulargrounds keeping.

Occasionally, a contractor may need to bebrought in. For example, for working in an under-ground vault or using a vacuum truck to clean acatch basin, you should consult a professional withthe tools and training to complete the job safelyand correctly. You should be sure that you, yourHOA and anyone hired are properly insured.

The Facilities maintenance guidelines section(pages 11-20 or 24) has more information aboutstormwater facilities, how each works, how tomaintain them and how to recognize problems,as well as hints about how to fix them.

REMEMBER: To fully complywith local laws, you need to checkthe maintenance manual for yourarea (see page 27 for local agencycontacts). It contains compre-hensive lists for recognizingpotential problems and how tomaintain facilities. You also canfind the manuals online at www.wceo.us/pages/stormwater-district.html

~ 9 ~

HOW TO RECOGNIZE STORMWATER

FACILITIESYour homeowners association should have accessto information about the locations and types offacilities serving your property. If the facility is pri-vately maintained, the association also should havea maintenance plan.

If your residential development does not have ahomeowners association or association documentshave no mention of stormwater management,look for information about locations and types of

facilities on the recorded plat for your subdivi-sion or in your property deed under “Covenants,Conditions, and Restrictions.” (CC&Rs).

The pictures and descriptions below should helpyou recognize stormwater facilities. Some may havefences around them for safety, especially thosewith standing water. If the facilities have problems,however, identification can be difficult.

For more information about facilities in yourdevelopment, contact your local agency (see page27) and ask a stormwater inspector to visit.

Dry facilitiesDry most of the time, these facilities contain waterduring and after rain storms. Water should disap-pear within three days after the rain stops.

recognize your facility

Detention basin (page 13) Stormwater is tempo-rarily stored and slowly released through an outletpipe. Natural-appearing vegetation is common.

Filter strip (page 11) is a strip of grass along paved areas such as a road or parking lot.

away.

Rain garden (page 11) is a bowl-shaped gardenwhere rainwater percolates into soil and native,deep-rooted plants.

Biofitration swale (page 11) is a flat-bottomedchannel where pollutants are removed by filtration,infiltration and settling.

continued on the next page

Underground facilities and structuresUnderground catch basins/storm drains, man-holes, vaults and drywells are invisible except for amanhole cover or inlet grate.

Wet facilitiesThese facilities typically contain water year-roundand often have significant aquatic vegetation.Water levels could rise during a storm, but shouldnot breach the structure.

Drywell (page 19) Vault (page 20)

Catch basins (also called curb inlets or storm drains - see page 18)

Underground structures are used to trapsediment and debris, allowing storm-water to soak into the ground and filterpollutants or are used as a junctionbetween pipes to route stormwater.

Retention Pond (page 15) is an open basin witha permanent pool of water where sediment and pollutants settle to the bottom.

~ 10 ~

SWALEA biofiltration swale uses grass or other denseplants to filter out sediment and oily materials.Swales often look like flat-bottomed channels withgrass growing in them. A swale is usually dry, butafter a storm, the runoff moves through it slowlyand at a shallow depth. As stormwater passesthrough the plants, pollutants are removed bythe combined effects of filtration, infiltration, andsettling. Any standing water should drain fairlyquickly.

Biofiltration swales provide treatment for pollu-tion but do not control the amount of stormwaterpassing through them.

FILTER STRIPA filter strip is a straightswatch of grass that re-moves sediment and oilsfrom stormwater. Usually,filter strips are along edgesof paved areas such as park-ing lots and roads.

For signs that maintenance is needed, tipson how to fix problems, and general maintenanceguidelines, see the next page.

biofiltration

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PROBLEM: Noxious weeds have taken over this

MAINTENANCE GUIDELINES

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RAIN GARDENA rain garden is a bowl-shaped garden whererainwater percolates into soil and native, deep-rooted plants. This garden can bevibrant and aesthetically pleasing and cando a better job of filtering stormwater thanother facilities. The size of this garden canbe small or big.

~ 12 ~

TIPS FOR FIXING PROBLEMS and general maintenance

Vegetation

• Remove weeds such as honeysuckle and thistle,then check for them on a regular basis andremove new honeysuckle sprouts.

• Remove all trees and saplings that block facilityelements or are within 15 feet of structures.

• Mow grass as needed to keep height at 4 to 6inches; remove clippings.

• Replace vegetation damaged or removed duringmaintenance.

• Avoid using fertilizers, herbicides or pesticideswithin or near the facility. These chemicals pol-lute the water and can cause unwanted plantgrowth.

Erosion

• Control by reseeding areas where soil is exposed,especially on slopes.

• Fill in eroded areas and seed with grass.

Sediment

• Removing sediment is best done in dry monthsbefore winter rains set in.

• If needed, seed and water during dry months tore-establish grass.

Trash and debris

• Pick up leaves before rains begin.

• Inspect and remove debris regularly, particularlyafter storms.

• Remove any material clogging drains, outfallsand channels.

MAINTENANCE IS NEEDED if you see these signs

• Bare, exposed soil

• Clogged inlet and outlet pipes

• Bottom of swale is eroded

• Sediment buildup, usually near inlet

• Unhealthy or dead vegetation

• Honeysuckle or other problem vegetation

• Overgrown vegetation

• Leaves, trash and other debris

biofiltration

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GOOD:trap in the foreground.

MAINTENANCE GUIDELINES

DETENTION BASINA stormwater detention basin is an open basin built by excavatingbelow ground or constructing above-ground berms or embank-ments. The detention basin temporarily stores stormwater runoffand slowly releases it through a specially designed outlet or controlstructure. Detention basins typically are designed to drain com-pletely within a few hours or days. Styles vary greatly, from wellmanicured to natural in appearance. Generally, more natural-appearingvegetation is preferred for reduced maintenance and enhanced wild-life habitat. Some facilities are designed to appear as natural waterbodies or park-like areas.

For signs that maintenance is needed, tipson how to fix problems, and general mainte-nance guidelines, see page 16.

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GOOD: Both photos show well maintained deten-tion basins. Shortly after a rain storm, the pool ofwater, above, is slowly draining. On the left, thebasin is dry between storms.

MAINTENANCE GUIDELINES

Additional elements to detention ponds

FIELD INLETA field inlet is a concrete structure thatcollects stormwater and routes it throughunderground pipes. Fitted with a slanted,slotted grate, it often traps sediment anddebris. Regular maintenance is impor-tant. Keep the opening clear of obstruc-tions. A field inlet is usually cleaned by atruck with a vacuum hose but sometimescan be cleaned with hand tools.

FLOW CONTROL STRUCT-

URE/FLOW RESTRICTORUnderground flow controlstructures and flow restrictorsdirect or restrict flow in or outof facilities. They slowly release

stormwater at a specific rate. It is important tomake sure they do not become plugged or damagedbecause the facility could release water too quicklyor too slowly and overflow. They are usually foundin manholes.

DEBRIS AND ACCESS BARRIER

A debris or access barrier is a bar grate over theopen end of a pipe larger than 18 inches in diam-eter that prevents large material, people or animalsfrom entering. They typically are located on theoutlet pipe from a detention basin to the controlstructure. For safety purposes, only qualified personnelshould remove debrisfrom the barrier whenwater is flowing throughthe pipe.

~ 13 ~

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INFILTRATION BASINA stormwater infiltration basin holds runoff andlets it soak into the ground. The basins are openfacilities with grass or sand bases. They can eitherdrain rapidly or act as permanent ponds wherewater levels rise and fall with stormwater flows.Infiltration facilities can be designed to handle allrunoff from a typical storm but could overflow ina larger one. Since the facility is designed to soakwater into the ground, anything that can clog thebase will reduce performance and be a concern.Generally, infiltration basins are managed likedetention basins but with greater emphasis onmaintaining the ability to infiltrate stormwater.

ponds

For signs that maintenance is needed, tipson how to fix problems, and general maintenanceguidelines, see page 14.

GOOD: Above shows a dry infiltration basin. Unlikea detention basin, an infiltration basin has an un-derground structure that helps water soak into theground. Below is a good basin shortly after a rain storm.

MAINTENANCE GUIDELINESP

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Additional elements to wetponds:

FIELD INLETA field inlet is a concrete structure thatcollects stormwater and routes it throughunderground pipes. Fitted with a slanted,slotted grate, it often traps sediment anddebris. Regular maintenance is important.Keep the opening clear of obstructions.A field inlet is usually cleaned by a truckwith a vacuum hose but sometimes can becleaned with hand tools.

FLOW CONTROL STRUCT-

URE/FLOW RESTRICTORUnderground flow control struc-tures and flow restrictors direct orrestrict flow in or out of facilities.They slowly release stormwater at

a specific rate. It is important to make sure they donot become plugged or damaged because the facil-ity could release water too quickly or too slowly andoverflow. They are usually found in manholes.

DEBRIS AND ACCESS BARRIER

RETENTION PONDA retention pond, or wetpond, is an open basin thathas a pool of water year-round. The volume of thewetpond allows sediment to settle out as stormwaterruns in. Wetland vegetation is typically planted toprovide additional treatment by removing nutri-ents such as phosphorus and nitrogen. Sometimes there are two pools. Stormwater flowsinto the first pool, where sediment settles beforemoving into the second pool. The water is thendischarged to streams and groundwater. Wetponds also have additional temporary stor-age above the permanent water level to detain andslowly release stormwater. They may be fencedfor safety.

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For signs that maintenance is needed, tipson how to fix problems, and general maintenanceguidelines, see page 16.

GOOD: Well maintained examples of wetponds. Above shows a two-pool wetpond.

MAINTENANCE GUIDELINES

~ 15 ~

A debris or access barrier is a bar grate over theopen end of a pipe larger than 18 inches in diam-eter that prevents large material, people or animalsfrom entering. They typically are located on the outlet pipe from a detention pond to the controlstructure.

For safety purposes, only qualified personnel shouldremove debris from the barrier whenwater is flowingthrough the pipe.

~ 16 ~

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SMAINTENANCE GUIDELINES

MAINTENANCE IS NEEDED if you see these signs

• Bare, exposed soil

• Slopes that are deteriorating

• Sediment that restricts flow or clogs inlet andoutlet pipes

• Sediment buildup; the facility is not draining orconveying runoff

• Unhealthy or dead vegetation

• Honeysuckle or other problem weeds

• Overgrown vegetation

• Holes in berms or slopes

• Leaves, trash and other debris

• Water surface is discolored or has a sheen

• Bottoms of slopes show signs of seepage andleaking

• Trees, often alders, growing on the slopes

TIPS FOR FIXING PROBLEMS and general

maintenanceVegetation

• Completely remove invasive species, such ashoneysuckle and thistle; check on a regularbasis to remove new honeysuckle sprouts.

• Remove cattails before they start to dominate afacility.

• Remove all unplanned trees or saplings thatblock parts of the facility or hinder maintenance.

• Make sure banks, slopes and areas designed forvegetation are planted with native or easy-to-maintain species. Avoid trees near the pond andon berms.

• Plant at appropriate times during the year so veg-etation can get established.

• Replace vegetation damaged or removed duringmaintenance.

• Check access roads and fencing, if the facility hasthem. They should be free of overgrown vegeta-tion and other materials so that the facility iseasily accessible for maintenance.

Erosion

• Control erosion by reseedingareas where soil is exposed,especially on slopes around astructure.

• Fill in eroded areas and coverthem with sod, mulch or othererosion control materials.

Sediment

• Removing sediment is best donein July and August before winterrains set in.

continued on next page

PROBLEM: This detention basinis overgrown with vegetation.

ponds

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SMAINTENANCE GUIDELINES

Trash and debris

• Pick up leaves before rains begin.• Inspect and remove debris regularly, particularly

after storms.• Remove any material clogging drains, outfalls

and channels.• Avoid using fertilizers, herbicides or pesticides in

or near the facility. Chemicals pollute the waterand can cause unwanted plant growth.

• Identify sources of leaks or spills and containthem as quickly as possible.

Mosquitoes

• Check inlets and any open or confined stand-ing water for mosquito larvae (see below). Ifmosquitoes are a concern, contact the WarrenCounty Combined Health District for information.

REPORT SPILLSChemical spills such as oil, gasoline, paint orherbicides/pesticides may cause harm to sur-face or ground water. Spills MUST be reportedto the Ohio Environmental Protection Agencyand to your local city or county. Do not attemptto rinse away the spill until it’s been checked. Ohio Environmental Protection Agency24-hour Spill Response Number:(800)-282-9378.

PROBLEM: The infiltration basin above still haswater more than three days after the rain storm.This indicates a problem that slows infiltration.

Fencing and access lanes

• Check roads and fencing in the facility. Theyshould be maintained to allow easy access.

Mosquito larvae.

~ 17 ~

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MAINTENANCE GUIDELINES

For signs that maintenance is needed, tipson how to fix problems, and general maintenanceguidelines, see page 20.

CATCH BASIN, CURB INLET, and

MANHOLECatch basins and manholes are underground con-crete structures typically fitted with a slotted gratebut may have a solid lid. They collect stormwaterrunoff and route it through underground pipes,allowing sediment and debris to settle. They alsocan be used as a junction in a pipe system to allowaccess.

Catch basin – also called a storm drain, it canbe a round structure but is typically square. It isused to collect stormwater from open areas.

Curb inlet – is a rectangular structure under-neath the curb of a roadway. Openings may be rectang-ular or square and are located in the gutter.

Manhole – is a round, concrete structure typi-cally ranging in diameter from 4 feet to 8 feet. It isan access point for underground pipe maintenance.Manholes generally have steps mounted on the sidefor easy access.

Catch basins, curb inlets, and manholes are builtinto almost all stormwater systems.

Above: Curb inlet.

Below: This manhole shows a well maintainedinterior.

PROBLEM: The photo below shows a catch basinwith a lot of sediment built up in it.

~ 18 ~

underground

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MAINTENANCE GUIDELINES

DRYWELLA drywell is an open-bottomed manhole used toinfiltrate stormwater into the ground through holesin the walls. Drywells rely on the stormwater soak-ing into the surrounding soil. They trap sedimentand oily pollutants in runoff, and they can fill withoily sediment in areas that lack treatment facili-ties. Because drywells can be clogged and tendto concentrate pollutants in one place, pollutionand sediment control practices should be used toprotect them.

For signs that maintenance is needed, tipson how to fix problems and general maintenanceguidelines, see page 20.

Additional elements to drywells

FIELD INLET

GOOD: Left photo shows the typical lid of adrywell. Above is a well maintained interior.

PROBLEM: Trash has collected inside thedrywell.

A field inlet is a concrete structure that collectsstormwater and routes it through undergroundpipes. Fitted with a slanted, slotted grate, itoften traps sediment and debris. Regular main-tenance is important. Keep the opening clear

of obstructions. Afield inlet is usuallycleaned by a truckwith a vacuum hosebut sometimes canbe cleaned withhand tools.

~ 19 ~

CONFINED SPACE WARNINGFOR UNDERGROUND FACILITIESDue to potential dangers, onlytrained and certified persons

should enter confined spaces. These are defined as:• Large enough that an individual could fully enter

the space and work.• Having limited or restricted entry or exit.• Not primarily designed for human occupancy.

For more information, visit www.osha.gov/publication/osha3138.pdf.

VAULTSClosed detention systemA closed detention system is an underground struc-ture, typically a concrete vault or series of largediameter pipes, which temporarily stores stormwa-ter and releases it slowly. They typically are usedon sites that do not have space for a pond. Theseunderground detentionsystems are enclosed spaceswhere harmful chemicalsand vapors can accumulate.Therefore, the inspectionand maintenance of thesefacilities can only be doneby individuals trained andcertified to work in hazard-ous, confined spaces.

Additional elements to vaults

FLOW CONTROL STRUCTURE/FLOW RESTRICTORUnderground flow control structures and flowrestrictors direct or restrict flow in or out of facili-ties. They slowly release stormwater at a specificrate. It is important to make sure they do notbecome plugged or damaged because the facil-ity could releasewater too quicklyor too slowly andoverflow. They areusually found inmanholes.

GOOD: Lid and entrance toan underground detentionfacility.

~ 20 ~

MAINTENANCE IS NEEDED if you see these signs• The facility drains slowly after a rain storm.• Leaves, trash and other debris slow or stop out-

flow or filtration.• There is sediment or debris accumulated in

storage area.

TIPS FOR FIXING PROBLEMS and general

maintenanceAccess to facility• Remove any vegetation covering the lid.

Maintenance• Inspection or maintenance that requires entering

the underground facility can only be done by in-dividuals trained and certified to work in hazard-ous confined spaces.

- Remove trash and debris regularly.- Identify sources of leaks or spills and contain

them as quickly as possible.- Remove sediment.

Mosquitoes• Check inlets and any open or confined stand-

ing water for mosquito larvae. If mosquitoes area concern, contact the Warren County CombinedHealth District for information.

underground

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REPORT SPILLSChemical spills such as oil, gasoline, paint orherbicides/pesticides may cause harm to sur-face or ground water. Spills MUST be reportedto the Ohio Environmental Protection Agencyand to your local city or county. Do not attemptto rinse away the spill until it’s been checked.

Ohio Environmental Protection Agency24-hour Spill Response Number:(800)-282-9378.

MAINTENANCE GUIDELINES

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TIPS FOR MANAGING STORMWATER AT

HOMEHomeowners can help maintain shared stormwa-ter facilities and protect the health of our streamsby managing the quality and quantity of rainwaterthat flows off their property.• Keep leaves, clippings, bark dust and soil on your

property.• Build a rain garden to keep runoff on your

site.• Reduce fertilizer, herbicides and pesticide use.• Plant native trees and plants; remove invasive

plant species.• Sweep patios, driveways and other paved areas

rather than hose them off. Bag or compost de-bris, don’t sweep it into the street.

managing stormwater at home

RESOURCESFor information about raingardens, native plants, naturalgardening and much more, visithttp://www.wceo.us/pages/Stormwater-District.html.

• Take your vehicle to a commercial car wash thattreats and recycles water.

• Make sure wastewater from washing the exteriorof your home or roof is not discharged into thestreet. Get permission to pump it to a sanitarysewer or infiltrate it directly into the grass orgravel.

• Dispose of yard and lawn trimmings properlysuch as composting, recycling or yard debrispick-up.

• Install permeable surfaces for sidewalks, patiosand driveways.

• Collect roof runoff in a rain barrel to use for wa-tering plants and garden.

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or compost de-eet.

nural, visits/

Understanding Stormwater

Drainage Maintenance

WARREN COUNTY STORMWATER DISTRICT

Home Owner’s Associa on Guide

Commercial properties could have unique storm-water features in addition to those typically foundin residential areas. These features include per-vious pavement, which allows rain on parkinglots and walkways to soak into the ground ratherthan run off; oil/water separators, undergroundstructures typically located in parking lots and atautomotive businesses; and exfiltration trenches.

Because these features often are out of sight orblend into their surroundings, maintenance caneasily be forgotten or overlooked. Regular inspec-tion and cleaning are important to keep thesestructures functioning properly and avoid poten-tially costly repairs. Maintenance is a requirementof state stormwater rules and local stormwaterordinances.

PERVIOUS PAVEMENT Pervious pavement allows water to pass throughit and soak into the ground, reducing runoff andmimicking the natural hydraulic cycle. Perviouspavement typically is a layer of specially formu-lated concrete, asphalt or pavers on top of a thicklayer of gravel (8 – 24 inches). As water passesthrough the pavement and gravel, contaminantsare filtered out. The water is stored in the gravellayer until it can soak into the ground. Perviouspavement requires regular maintenance to allowwater to pass freely.

MAINTENANCE IS NEEDED if you see these signs:

• Standing water during or after rainfall (see photobelow)

• Visible debris or sediment on pavement surface• Height of gravel between pavers depleted

by more than ½-inch (permeable pavers only)

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MAINTENANCE GUIDELINES

PROBLEM: This pervious concrete needs atten-tion; there should be no standing water.

GOOD: Pervious asphalt, note the coarse appearance.

REMEMBER: To fullycomply with local laws, youneed to check the main-tenance manual for yourarea (see page 27 for localagency contacts). It con-tains comprehensive listsfor recognizing potentialproblems and howto maintainfacilities.

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businessesMAINTENANCE GUIDELINES

Pervious pavers, note the spaces between the pavers.

OIL/WATER SEPARATOR An oil/water separator treats stormwater by trap-ping oil at the surface of the water and sediment atthe bottom, allowing treated water to pass through.It is most commonly used as the first pre-treatmentfacility in a series of stormwater managementfacilities and is usually found in parking lots, ser-vice and fuel stations. A unit should be inspectedmonthly and after a major storm. Make sure tokeep records of your inspections and maintenanceactivities.

• Discharge water shows obvious signs of oil orother contaminants

• Thick layer of oil (more than 1 inch) on surface ofwater in vault

• Sediment accumulation of more than 6 inches onthe bottom of the vault

• Accumulation of trash or debris

TIPS FOR FIXING PROBLEMS and general

maintenance:• Vacuum or sweep pavement frequently, prefer-

ably at least twice a year.• Wash pavement using high pressure water at

least once a year.• Do not allow dirt or landscaped areas to drain or

erode onto pervious pavement.• Repair and patch pervious pavement with similar

pervious material and gravel layer.• Permeable pavers only: distribute gravel over

pavement and sweep into joints between pavers.• Replace broken pavers as needed to prevent

structural instability.

Problem: Some oil/water separators include coalescing plates (wavy-edged sheets shown above) that separate oil from water, so it can then be skimmed off. Plates should be white when clean.

MAINTENANCE IS NEEDED if you see these signs

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TIPS FOR FIXING PROBLEMS and general

maintenance:• Inspection or maintenance that requires enteringthe underground facility must be performed by atrained and certified expert. Cleaning and properdisposal of sediments and oils can be done bymost environmental contractors. Be sure to keepcopies of the disposal records.• Remove trash and debris regularly.• Identify sources of leaks or spills and containthem as quickly as possible.• Oils and sediment should be removed and prop-erly disposed of (not in the trash)• Secured, floating, oil-absorbent pads can be usedto extend the maintenance period.

GOOD: A well maintained oil/water separator.

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Exfiltration TrenchAn exfiltration trench is a feature built in to the curband gutter system to infiltrate stormwater. The firstlayer of an exfiltration trench is made up of porousconcrete which allows road runoff to soak in. Thewater is then filtered through other porous material(such as gravel and sand) below the surface of theconcrete before it enters into a perforated pipe. Theperforated pipe then carries the clean water to thestormwater system underground. Exfiltration trenchesare used most commonly in roadways where there is notspace available for traditional ponds or swales.

MAINTENANCE IS NEEDED if you see these signs:

• Standing water during or after rainfall (see photobelow).

• Visible debris or sediment on pavement surface.• Vegetation growth in porous material.

GOOD: Exfiltration trench.

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Best Management Practices or BMPs –Multiple treatment methods, activities, facilitiesand structures that, used together, help protectwater quality by preventing or reducing pollutionof stormwater and removing pollution from runoffbefore it is discharged to ground or surface water.

Biofiltration swale – A broad, open, vegetatedchannel that filters flowing stormwater. The mostcommon form is a wide, shallow, inclined depres-sion planted with grasses.

Catch basin or storm drain – A round or squarestructure typically fitted with a slotted grate that isused to collect stormwater runoff from open areasand route it through underground pipes. It allowssediment and debris to settle out of the runoff andcan have inserts or other fittings to trap oils andfloatables. A catch basin also can be used as ajunction in a pipe system and have a solid lid.Maintaining a catch basin often requires specialexpertise and equipment.

Closed detention system – An undergroundstructure, typically a concrete vault or series oflarge diameter pipes, that temporarily storesstormwater and releases it slowly. A system typi-cally is used for sites that do not have space foran above-ground system. It is accessed through amanhole lid.

Covenants, Conditions, and Restrictions(CC&Rs) – Non-governmental rules and require-ments specific to a condominium or homeownersassociation. Requirements for residents rangefrom lawn upkeep to financial responsibility formaintaining common areas, potentially includingstormwater management facilities.

Curb inlet – A rectangular structure underneaththe curb of a roadway. Openings may be rectangularor square and are located in the gutter (see right).

Detention facility – A pond, vault or pipe whichtemporarily stores stormwater runoff and slowlyreleases it through a specially designed outlet.Detention facilities are designed to drain complete-ly within a few hours or days.

Detention pond/basin – An open basin built byexcavating below ground or constructing above-ground embankments. It temporarily stores storm-water runoff and slowly releases it through a speciallydesigned outlet.

Discharge point/outfall – The place where a storm-water system empties into a stream or other body ofwater.

Drywell – An underground, concrete structurethat allows stormwater to soak into the groundthrough holes in the walls and/or open bottom.Maintenance often requires special expertise andequipment.

glossary

Curb inlet.

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Exfiltration system - A strip of pavement thatdrains stormwater into a pipe that transportsstormwater.

Field Inlet - A concrete structure, fitted with aslanted, slotted grate that collects stormwater androutes it through underground pipes.

Filter strip – A strip of grass, usually along edgesof parking lots and roads, that filters stormwater byremoving sediment and oils before the water soaksinto the ground.

Filter vaults or stormwater filters –Underground vaults, manholes or specialized catchbasins that include a series of filter cartridges tocapture sediment and pollutants before stormwa-ter flows into a pipe system. Types of pollutantsremoved depends on the medium used in the filtercartridge.

Flow control structure/flow restrictor/outlet structure – A structure that restricts orslowly releases stormwater at a specific rate toreduce flooding and stream erosion and filterspollutants. May utilize an orifice plate for addtionalflow restriction.

HOA – Home Owner Association.

Infiltration basin – An open basin built by exca-vating below ground or constructing above-groundberms, or embankments. It temporarily storesstormwater runoff and disposes of it by letting itsoak into the ground.

Manhole – An underground, concrete structurethat provides maintenance access to pipes thattransport stormwater runoff. It is usually found inpaved areas and has a solid lid.

Oil/water separator – An underground vaultthat treats stormwater by mechanically separat-ing oil from water. The oil rises to the surface andfloats on the water and sediment settles to thebottom. (continued)

Oil/water separators are typically usedwhere high oil concentrations are anticipated inthe stormwater runoff. For example, parking lots,service and fuel stations.

Permeable pavement – Specially constructedpaving surfaces that allow water to pass throughand soak directly into the ground.

Rain garden – Specially designed, site-specificstormwater facility that use plants and soils tocapture pollutants and allow stormwater to soakinto the earth.

Retention pond – An open basin, built by excavatingbelow ground, that has a year-round pool of water.The volume allows sediment to settle out. A wet-pond also detains water using additional temporarystorage above the permanent water level to storeand slowly release it.

Storm drain or curb inlet – A type of catch ba-sin that collects and conveys stormwater runoff.

Stormwater treatment facility – A landscapedfeature or structure that captures, conveys, slows,detains and/or treats stormwater. They includedetention facilities and retention facilities.

Stormwater runoff – Water from rainstorms,irrigation or other sources, that flow across and offa hard area, such as a street, paved lot, roof or side-walk, that prevents it from soaking into the ground.

Stormwater system – A system of catch basins,pipes and/or facilities for conveying, detaining ortreating stormwater. Not to be confused with asanitary sewer, which carries wastewater to a treat-ment facility.

Treatment wetland – A shallow man-made pond designed to treat stormwater through thebiological processes associated with aquatic plants.These facilities use dense wetland vegetation andsettling to filter sediment and other pollutants outof stormwater.

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contacts and resources

WARREN COUNTYWarren County Engineer’s Office, Stormwater District210 W. Main St.Lebanon, OH 45036

(513) 695-3301

Website: www.wceo.us/pages/Stormwater-District.html

E-mail: [email protected]

Warren County Stormwater FacilityMaintenance Manualhttp://www.wceo.us/pages/Stormwater-District.html

Warren CountySoil and Water Conservation District320 E. Silver St.Lebanon, OH 45036

(513) 695-2830

Website: www.warrenswcd.com

E-mail: [email protected]

Warren CountyCombined Health District,Environmental Health416 S. East St.Lebanon, OH 45036

(513) 695-1228

Website: www.wcchd.com/environmental-health.aspx

DEERFIELD TOWNSHIPDeerfield TownshipPublic Works Department4900 Parkway Dr., Suite 150Mason, OH 45040

(513) 701-6958

Website: www.choosedeerfield.com

E-mail: [email protected]

Deerfield Regional Storm Water District(513) 701-6958

Website: deerfieldstormwater.com

E-mail: [email protected]

OHIO EPAOhio EPADivision of Surface WaterMailing address:PO Box 1049Columbus, OH 43216-1049Street address:50 West Town St., Suite 700Columbus, OH 43215

(614) 644-2001

Website: www.ohio.epa.gov/dsw

E-mail: [email protected]

To report spills or for environmentalemergencies please call the EmergencyResponse Hotline: (800) 282-9378

RESOURCES

Find links to all agency stormwater manuals, comprehensive maintenance checklists that alsoshow how to recognize and fix problems for all facilities in this book and other less common facilities,videos, the information in this guidebook, news and workshops schedule and more... ...at www.wceo.us/pages/stormwater-district.html

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notes