The Maintenance of Residential Stormwater Management Areas

Untied StatesDepartment ofAgricultural

NaturalResourcesConservationService

The Maintenance ofResidential StormwaterManagement Areas

March 2000

The Maintenance of Residential Stormwater Management Areas I

A Product of the Mid-Atlantic Interdisciplinary Resource Team

Mid-AtlanticInterdisciplinaryResource Team

The Maintenance ofResidential StormwaterManagement Areas

Contents

Introduction and background .............................................. 1Brief description of wet and dry ponds .............................. 1Maintenance types ................................................................ 1Maintenance considerations ................................................ 4Inspection checklists ............................................................ 5Debris and obstructions removal ........................................ 5Erosion and sediment control ............................................. 5Structural and mechanical equipment ................................ 5Vegetation maintenance ....................................................... 5Wildlife maintenance ............................................................ 7Other concerns ...................................................................... 8References .............................................................................. 9Appendix 1: Natural resource professionals .................. 10Appendix 2: Inspection checklist ..................................... 11Appendix 3: Details for the construction of houses ...... 12

for purple martins, swallows, and bats

Acknowledgments

Carl DuPoldt, USDA, NRCS, East Reg. Urban Cons. IRT, Hammonton, NJ

Julie Hawkins, USDA, NRCS, Mid-Atlantic IRT, Dover, DE

Marianne Hardesty, USDA, NRCS, Newark, DE

Pete Marole, New Castle County Department of Special Services, Newark, DE

Cathy Martin, Fisheries Biologist, Delaware Department of Natural Resources and EnvironmentalControl, Division of Fish and Wildlife

Richard Mickowski, New Castle Conservation District, Newark, DE

Debi Weiker, New Castle Conservation District, Newark, DE

March 2000

II The Maintenance of Residential Stormwater Management Areas


The United States Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, nationalorigin, gender, religion, age, disability, political beliefs, sexual orientation, and marital or family status. (Not all prohibited bases apply to all pro-grams.) Persons with disabilities who require alternate means for communication of program information (Braille, large print, audiotape, etc.) shouldcontact the USDA’s TARGET Center at (202) 720-2600 (voice and TDD).

To file a complaint of discrimination, write USDA, Director, Office of Civil Rights, Room 326W, Whitten Building, 14th and Independence Avenue, SW,Washington, DC 20250-9410, or call (202) 720-5964 (voice or TDD). USDA is an equal opportunity employer.

Issued January 2000

The Maintenance of Residential Stormwater Management Areas 1


Introduction and Background

Prior to the implementation of stormwatercontrols, construction and development oftenresulted in severe alterations of watersheddrainage patterns. These alterations causeddownstream flooding on residential and com-mercial properties, as well as low-lying roadcrossings. Uncontrolled stormwater volume alsoincreases streambank erosion and results inmajor detrimental changes in the physicalcharacteristics of receiving streams. Residentialand commercial land uses often dischargepolluted stormwater runoff, which can reachwaterbodies unless control mechanisms are inplace. This polluted runoff is also referred to asnonpoint source pollution. Federal, state, andlocal laws and regulations require stormwatermanagement and the control of nonpoint sourcepollution.

Homeowner associations and property managerscan perform simple and routine maintenance oftheir stormwater management facility. Moredetailed complex maintenance and repair wouldrequire contracting with professional consult-ants. The goals of an effective maintenanceprogram should be to prolong the service life ofthe stormwater facilities, minimize expensiverepair costs and avoid adverse downstreamimpacts.

This guidance document has been prepared forhomeowner associations and residential andcommercial property managers to help themunderstand the basic maintenance needs forstormwater management areas.

Brief Description of Wet and Dry Ponds

Two of the most common types of best manage-ment practices that address stormwater manage-ment are dry ponds and wet ponds.

A dry pond (fig. 1) is a stormwater managementfacility that temporarily stores incomingstormwater. The pond typically is dry betweenstorm events. Dry ponds should incorporateextended detention of runoff from small rainfallevents to trap first-flush nutrients. The primarypurpose of dry ponds is to reduce and delaystormwater runoff peaks. The benefits are reducedpotential for flooding and erosion in downstreamareas.

A wet pond (fig. 2) is a stormwater managementfacility, which includes a permanent pool of waterfor enhancing water quality and additional capac-ity above the permanent pool for detainingstormwater runoff. Wet ponds fill with stormwaterand release most of it over a period of a few days.The benefits of a wet pond include those of the drypond and additional water quality and wildlifeimprovements.

Maintenance Types

Routine and non-routine maintenance items areshown in table 1. Routine maintenance includesitems that associations and property managersshould perform. Non-routine maintenance itemsare those that homeowner associations and prop-erty managers should be aware of, but should behandled by a natural resource professional. Anatural resource professional is a person who hasbeen trained in ecology and/or environmentalassessment including soils, plants, animals, airquality, human involvement, and water quantityand quality (appendix 1). Structural items mayrequire the expertise of an engineer.

Homeowner associations should retain a copy ofthe design drawings and planting layouts for thestormwater management facilities. It is recom-mended that structural areas be checked at leastannually and after major storm events.

The Maintenance of ResidentialStormwater Management Areas

wendy Pierce

wendy Pierce


2 The Maintenance of Residential Stormwater Management Areas

Top of berm

Vegetativebufferstrip

Shallowmarsh

Inflowenergy

dissipator

Riprapbaffle

Water quality storage

Trash rack

Low flow channel(optional)

Emergencyspillway

Concrete box outletstructure alternative

Trash rackEmbankment

Outlet energydissipator

Forebay

1 ft Peak attenuation storage

8 to 18-inch deepshallow marsh

(optional) Riprapbaffle

Low flow channel invert(optional)


Source:Pennsylvania Handbook of Best Management Practices for Developing Areas, spring, 1998.

Figure 1 Dry Pond - Plan and Elevation



1 ft

1 ft

3 to 6 ft

Peak attenuation storage


Permanentpool Outlet

Gabion earthbaffle

(optional)Aquaticbench

Terrestrialbench

Forebay

Maximum pool

Embankment

Access roadaround basin

No treeson embankment

Outlet structurealternative

Outfall

Emergencyspillway

Maintenanceright-of-wayto sedimentforebay

Stabilized bottom preferred

Sedimentforebay

Energydissipator

Inlet

Vegetativebufferstrip

Side slopesmax 3:1

Gabion/earthbaffle (alternative)

Outlet structurealternative riserwith hood

Terrestrial bench and buffer at toe of slope

Aquatic bench

Source:Pennsylvania Handbook of Best Management Practices for Developing Areas, spring, 1998.

Figure 2 Wet Pond - Plan and Elevation



Maintenance Considerations

Visibility of the Facility—Community needs andpreferences determine to a large extent the typeand amount of necessary maintenance for aestheticpurposes. Maintenance needs vary greatly depend-ing upon the type of vegetation.

Upstream Conditions—Watershed conditionsabove the facility will largely determine the typeand amount of sediment and other pollutants thatare entering that facility.

Safety—Some tasks can be carried out by non-technical staff or residents quite effectively. How-ever, all programs should carefully ensure thesafety of anyone carrying out maintenance tasks,and often a professional should be hired to conductthe work. Confined spaces should never be enteredwithout proper training and permits from occupa-tional and safety regulatory agencies as thesespaces may accumulate toxic and flammable gases.

Need for Professional Judgment—Professionaljudgment should be solicited regularly to ensurethat all needs of the facility are met. Even thoughsome maintenance tasks can be routinely per-

formed by property owners, there are many prob-lems that are not obvious to the untrained eye.(appendix 1).

Carrying out the maintenance plan—In the execu-tion of a maintenance plan, safety, cost, and effec-tiveness of the maintenance activities need to bebalanced. Some minor maintenance items can beaccomplished by the facility owners, such as litterremoval, light weeding, and light mowing. Forsediment removal, however, the best solution is tocontract with a professional. Mowing and handlingof a wheelbarrow can be dangerous on the slopingembankments of a wet or dry pond. Filling erodedareas and soil disturbing activities, such as resoddingor replanting vegetation, are also items that a profes-sional landscaping firm might best manage. Inaddition, trained personnel will be able to identifypotential problems early or when it is most cost-effective to correct. Most maintenance needs are sitespecific.

Financing—A fund should be established to providefor the costs of long-term maintenance needs. Theselong-term needs might include extensive sedimentremoval, structural repairs, landscaping, invasiveplant management, and removal of debris and litter.

Non-routine maintenance

Major bank stabilization

Inlet and outlet structure maintenance/replacement

Mechanical components maintenance

Structural repairs - embankments, inlets,outlets, pipe replacement/repair, removal offallen trees

Removal of excessive sediment

Rare conditions (extremely low pH, spills ofoils and toxic materials, swimming poolwater draining)

Removal of excessive algae and aquaticvegetation

Table 1 Routine and non-routine maintenance items

Routine maintenance

Visual inspection

Debris/litter control

Maintaining upstream undisturbed areas tominimize invasive vegetation

Nutrient excesses and odors

Minor bank stabilization and erosion con-trol - sheet & rill

Minor sediment removal - shovel, rake, pick,or wheelbarrow

Vandalism & fence maintenance

Algae and aquatic vegetation

Mowing and harvesting of upland vegetation



Inspection Checklists

Checklists are particularly helpful to associationsand property managers during routine inspections.See appendix 2 for a sample.

Debris and Obstructions Removal

Special attention should be given to the removal offloating debris (branches, paper, trash, and othersynthetic or natural materials) that can clog theoutlet device or riser. The benefits of debris removalinclude the following:• Reducing the chance of blocking in the outlet

structures, trash racks, low flow channels, andother facility components

• Preventing possible damage to vegetated areas• Reducing potential mosquito breeding habitats• Improving facility appearance• Reducing conditions for excessive surface algae

Erosion and Sediment Control

It is very important to ensure the integrity of thevisible banks, slopes, and bottom of ponds. Healthyground cover must be routinely maintained on allembankments of wet and dry ponds and on thebottoms of dry ponds. Bare areas should be re-seeded and stabilized as quickly as possible depend-ing on the season of the year. In the winter, considerusing synthetic materials and then reseed andstabilize with vegetation during the growing season.If left unchecked, erosion will result in sedimentdepositing in the facility.

The roots of woody vegetation, such as trees andshrubs, tend to destabilize the embankments. Con-sistent mowing of the embankment and emergencyspillway will prevent the trees and shrubs fromtaking root. Woody growth away from the embank-ment does not generally pose a threat to the stabilityof the embankments and can play an important rolein maintaining a healthy pond ecosystem. Trees andshrubs, however, should be planted outside ofmaintenance and access areas.

Structural and Mechanical Equipment

Maintenance of these items are usually beyond thecapabilities of homeowner associations. If a problemis observed, it is a good idea to have a professionalinvestigate and correct the problem early before itbecomes a major expense. Some of the structuresand equipment that may be encountered are asfollows:• valves• sluice gates• fence gates• locks• access latches• aeration equipment• pumps• inlet and outlet structures

Vegetation Maintenance

Turf maintenance—To ensure grass vigor, maintainas an upland meadow by cutting no shorter than 6 to8 inches high during non-nesting periods. If a moremanicured lawn setting is desired, more mowing andspecial attention to turf health will be needed. Somecommunities consider the tall wetlands-type vegeta-tion (typically, cattails or rushes) that may grow indry ponds as unaesthetic. Some of this vegetation isactually beneficial as it provides water qualitybenefits and wildlife habitat. Some vegetative needsinclude the following:• pH adjustment (as required)• pruning• pest control• reseeding• thatch removal• weed removal

Sediment filtration—Vegetative cover around thepond filters sediment from runoff as it flows into thepond. It also prevents erosion of the banks of thepond. A minimum 24-foot vegetated buffer strip isideal around wet ponds. This buffer strip should bemowed no more than four times per year or once ayear where wildlife habitat is a concern. Mowingrequirements can be tailored to the specific needs ofa particular site and the adjacent neighbors.



Surrounding vegetation fertilization (not recom-

mended except in special cases)—It is importantnot to over fertilize the surrounding vegetation. Thiscould result in excess nutrients being washed intothe pond, which can contribute to excessive algaegrowth. As a general rule, the nutrient needs of thesurrounding vegetation should be evaluated bytesting the pH and nutrient content of the soil priorto fertilization. The adjustment of pH may be neces-sary to maintain vegetation. Fertilization of all turfareas should occur in the fall of the year.

Purple loosestrife (fig. 3)—If your wetland and/orstormwater management area becomes invaded withpurple loosestrife, there are methods to reduce itspresence. It is important to catch its presence early,which is evident by the long purple flower head. Torid the wetland and/or stormwater management areaof it manually, both plants and rhizomes (largetuberous root systems) must be removed prior toflowering (June through September). Place plantparts immediately in a bag to prevent further spreadof the species. If it is not possible to do this, regularremoval of the flower heads before the seeds aredispersed will help keep this plant at bay. Digging isnot recommended, as it creates disturbance whichfavors the spread of the species. Herbicides aregenerally not effective for purple loosestrife, as itsseeds are long-lived; therefore, it only provides for ashort-term solution. If herbicide applications areused, they will need to be repeated for several years.As a caution, purple loosestrife may be available atlocal nurseries. Do not introduce this plant into pondareas.

Cattails and common reed (Phragmites)—It isimportant to find out what plants were originallyplanted when the pond or stormwater wetland wasconstructed. Ponds and stormwater wetlands wereoriginally designed with the intent of retainingstormwater; hence, only one or two plant specieswere planted. Water quality treatment and wildlifeimprovements have since been added to theirdesign, increasing the diversity of plants used in theponds.

Shallow water (less than 2 feet) will often be takenover by water-loving plants. Dense, tall, emergentvegetation, most commonly cattails (fig. 4) andphragmites (fig. 5), may limit waterfowl use of apond. Cattails provide good wildlife habitat but cantake over a shallow pond and obstruct water man-agement. Phragmites is much more invasive, tallerand generally does not provide for a scenic view.Once established, phragmites is very difficult tocompletely eradicate.

Too dense of a stand of cattails and/or phragmitescan reduce populations of invertebrates, amphibiansand reptiles and may possibly increase the mosquitopopulations. It is important to keep approximately30 to 50 percent of the pond surface as open water.Eradication of these plant species generally requiresthe assistance from a natural resource professional.

With respect to diversity, research has shown thatlower pollutant inputs generally yield greater plantdiversity. Conversely, higher pollutant inputs yield

Figure 3 Purple loosestrife Figure 4 Cattails Figure 5 Phragmites



lower plant diversity. Hence, if your pond becomespopulated with phragmites, cattails or both, it mayalso indicate a high pollutant load. These two plantsare among the best plants for improving waterquality.

It is recommended that homeowner associationsdecide early on how much they are willing to spendin time and effort on vegetation maintenance.

Wildlife Maintenance

Beaver (fig. 6) have been known to take up resi-dence in facilities with ponded water. Beaver can cutdown small shrubs and trees adjacent to the pondand may cause an increase in the amount ofponding. If excessive tree damage or ponding isobserved contact a natural resource professional.Beaver will attempt to block the pond inflow andoutflow structures.

Resident Canada geese (fig. 7) may also be aproblem in your stormwater wetlands or ponds. Iftoo many geese populate the area, their excretionsmay cause algal blooms and odor problems. Theirpaths, created by feeding on new shoots of grassand continuous trampling may also cause smallgullies to form. To keep the resident Canada geesepopulations low, it is important to maintain anarea around the pond to its edge with high grassesand shrubs. A width of approximately 24 feet isrecommended. Do not feed geese as it encouragesthem to stay.

Muskrats and groundhogs (fig. 8)–Other animals,such as muskrats and groundhogs, may dig outburrows that could deteriorate the structural integ-rity of an embankment. Muskrats, in particular, willburrow tunnels up to 6 inches in diameter. Existingburrows should be filled as soon as possible tominimize animal burrowing. Another measure couldinvolve trapping of the muskrats if the problembecomes extensive.

Snapping turtles (fig. 9)–Warn small children thatthey should not pick up snapping turtles. It is recom-mended that local fish and wildlife professionals becontacted regarding the number of snapping turtlesin a specific pond to maintain its ecological balance.Snapping turtles differ from other turtles by theirridges on the shell and tail and their hooked beak.

Figure 6 Beaver

Figure 9 Snapping turtle

Figure 7 Canada geese

Figure 8 Muskrat



Other Concerns (mosquitoes, algae, fish

kills, and odors)

Mosquitoes are not as big a problem as is oftenperceived. There are proven control strategies thatcan be used. While ponded water can createmosquito and other insect breeding habitat, it alsoprovides habitat for insect predators, such as birds(swallows and purple martins), fish, frogs, bats,and dragonflies, to keep the nuisance populationsin check. The best mosquito control technique inponds is to prevent stagnant areas from forming inthe permanent pool.

Mosquito management tips:

• Manage wetlands to minimize the formation ofstagnant pools.

• Encourage flowing water conditions by remov-ing debris and excessive vegetation.

• Provide vegetative cover for the water surface.• Provide nesting and perching structures for

purple martins, swallows, and bats(appendix 3).

• Encourage aquatic predation; i.e., introducefish and frogs.

Algae—Heavy algal growth is caused by excessnutrients, warm water, and sunlight. Controlmethods vary depending on the type of algae.Contact a natural resource professional for assis-tance in controlling excess algae.

Fish kills can result from an imbalance in theecological system or if there is a direct dischargethrough the storm sewer system, such as chlori-nated swimming pool water, vehicle oil, car washdetergents, and other household chemicals. Fishkills can also result from algal die-offs. The home-owner associations should adopt a storm sewerstenciling program to help promote an understand-ing that storm sewers flow to the basin and then toa nearby stream.

Odors are generally not a problem. Sometimes asulfur odor is evident, but this is usually verylocalized and present when there is very little windcurrent. Algal die-offs can result in strong odorsfrom the pond. If odor becomes a big problem in awet pond, contact a natural resource professional.

Aesthetically, your pond should mimic naturalpond conditions. This includes a variety of habi-tats for plants and animals as well as some openwater.



References

Alliance for the Chesapeake Bay and U.S. Fish andWildlife Service, Chesapeake Bay Field Office,Basin scaping to conserve water–a home-owner’s guide. 1994.

Alliance for the Chesapeake Bay and U.S. Fish andWildlife Service, Chesapeake Bay Field Office,Conservation landscaping–a homeowner’sguide. 1994.

Berger, Louis & Associates, Inc. ConstructedWetlands Design Workshop. A series of paperspresented at the Delaware Erosion, SedimentControl, and Stormwater Conference, Septem-ber 15-18, 1998.

Delaware Department of Natural Resources andEnvironmental Control, Division of Soil andWater Conservation Sediment and StormwaterProgram. Stormwater management pondmaintenance-guidance for the maintenanceorganization. September 1992.

Livingston, Eric H., Earl Shaver, Joseph J. Skupien,and Richard P. Horner. United States Environ-mental Protection Agency, Office of Water,Washington, DC. Operation, maintenance, andmanagement of stormwater managementsystem. Watershed Management Institute, Inc.August 1997.

Meyer, Fred P., and Lee A. Barclay. Field manualfor the investigation of fish kills. U.S. Fish andWildlife Service, National Fisheries ResearchCenter, LaCrosse, WI and U.S. Fish and WildlifeService, Division of Environmental Contamina-tion, Washington, DC.

Montgomery County, Department of Environmen-tal Protection, Montgomery County, Maryland.Maintaining urban stormwater facilities–aguidebook for common ownership communi-ties, circa 1990.

Montgomery County, Pennsylvania. Stormwaterbasins—making them more functional andattractive. October 1992.

Nuss, J. Robert, Professor of ornamental horticul-ture. Landscaping with native plants or nativeplants in the landscape. Penn State University.June 1998.

Penn State University, College of AgriculturalSciences Cooperative Extension. Providingwetlands for wildlife while controllingstormwater, circa 1990.

Prince George’s County Department of Environ-mental Resources. How does your gardengrow?–a reference guide to enhancing your raingarden, circa 1998.

Shaver, Earl, and John Maxted. Construction ofwetlands for stormwater treatment. DelawareDepartment of Natural Resources and Environ-mental Control. December 1993 (unpublished).

State of New Jersey, Department of EnvironmentalProtection, Division of Water Resource. OceanCounty demonstration study–stormwatermanagement facilities maintenance manual.Ocean County Planning and Engineering De-partments and Killarn Associates. June 1989.

United States Department of Agriculture, NaturalResources Conservation Service, NationalAssociation of Conservation Districts, andWildlife Habitat Council. Backyard conserva-tion–bringing conservation from the country-side to your backyard. April 1998.

United States Environmental Protection Agency.Stormwater management system, inspectionforms. Watershed Management Institute, Inc.August 1997.



Appendix 1 Suggested format for listing local natural resources professionals

Agency and contact person Address Phone FAX

number number

Local Conservation Districtoffice

Local CooperativeExtension Service office

United States Department ofAgriculture, NaturalResources ConservationService office

Local Fish and WildlifeService office for game andnon-game species

Private consultants

Other natural resourceprofessionals:



A Minimum Inspection Checklist for Stormwater Ponds

Item to check Dates observed and/or corrected Comments on what observed

(attach a sketch)

Observed Corrected

Note: Inspections should occur at least annually and after major storms or as a follow-up to a complaint.

Appendix 2

Obstructions of theinlet or outlet struc-tures by trash anddebris

Excessive erosion orsedimentation in thebasin

Inspect the embank-ment area to ensureintegrity (holes, trees,roots, weeps, seeps,slumping, and faults)

Depression or wetspots in the bottom ofa dry pond

Deterioration of pipes

Condition of theemergency spillway

Erosion of the em-bankments and sideslopes (erosion andgullies)

Upstream and down-stream channelconditions

Signs of vandalism

Other items



Expanded view of martinhouse. A threaded rodinserts through the baseand up through the chimney.

Entrance hole diameter2 1/4". Locate 5/8" ventilationholes 1" below top edge ofsides.

Note: This plan is for a one-story house. To add asecond story, make onemore ceiling unit (25" x 25")four more sides, and fourmore room partitions.

96"48

"

25"

18 3

/4"

6 1/4"9 3/8"

9 3/8"

1" 1"

6 1/4"

1/4"

1/4"

3 1/4"

3"

5"

3 1/4" 5/8" diameter3"

12" 12"

6"Side (2)

25" 25" 25"

6"Side (2)

Boards for base

6"Room

partition (4)

End roof support (4)

24"

Center roof support (2)

25" 24"

10"5"10"

14 1/8"

Layout pattern

(not shown)Place 1/2 inch dowelrailing around balconyto keep young fromfalling.

Place the house onthe cedar post at aheight of 10-20'.

Materials

4' x 8' x 1/4" plywood2" x 2" x 6" for chimney1" x 2" x 14' (base)1" x 1" x 8' (corner blocks)4" x 8" metal window screen4" x 4" x 14' cedar post(recommended for the fixedheight house)

Ceiling (1)Floor (1) Roof

side

(2)

18 1/2"6"

6"

1 1/2"

Waste

6"

5"

5 3/4"2 1/4"

Diameter

1 1/2"

25" 23 1/2" 11"11"

Screenplacement

Purple Martin house(Plans from Penn State College of Agricultural Sciences Cooperative Extension.)

Appendix 3 Details for the construction of houses for purple martins, swallows, and bats.



1 3/8"

2 1/

4"

(Up)

9"

4"13

1/2

"

9"

6"

7"

5 1/2"

5 1/2"

2 1/4"

*

*

5 1/2"

5 1/2"

13 1/2"

5 1/2"

7" 9" 9" 9" 4"

1/4" holes

1/4" holes

Waste

Lumber:One 1" x 6" x 6'

*Note: If slot entrance is used frontwill measure 5 1/2" x 7". Leaveopening at top.

Note:Entrance hole for Great CrestedFlycatcher shouldbe a round hole 1 1/4"in diameter

Pivot nailin front

Pivot nailin back

Two "pivot" nails allow side to swing out for cleaning.Use one nail at bottom to close side.Nail holds side closed.

Place the house 4' above groundwith the entrance hole facing east.

Side

(2)

Floor

Back

Back Roof Front Side Side Flr

Roof

Front

Nest box for Tree Swallow(Plans from Penn State College of Agricultural Sciences Cooperative Extension.)



Roof supports

Spacers

Vent

Side view

Bottom view

Bat house design

1. Measure and mark all wood: back 1' 6" by 2’; roof 1' 7" by 6 1/2"; interior pieces 1' 4 1/2" by 1/2"; fronttop 1'6" by 9 1/16"; and front bottom 1'6" by 5 1/2".

2. Cut six pieces of netting 14" x 21". Staple to partitions.3. Screw back to sides, caulking first. Be sure top angles match.4. Cut a piece of netting 16" x 30" and staple to inside surface of back. Be sure netting lies flat and does

not pucker.5. Construct house as per drawings above. Place spacers on partitions, screw top front piece to sides

first, then screw bottom front piece to sides to create a 1/2" vent between the two, attach roofsupports, attach roof.

6. Caulk between roof and sides, sides and front pieces, and sides and back piece so as to seal houseairtight. Do not allow screws to protrude into roosting chamber. Paint exterior at least twice withappropriate color.

7. Place bottom of box 10' above ground on a building or pole and orient the box to southeast orsouthwest.

(Plans from Penn State University and PA Game Commmission. Designed by Lisa Williams)

The Maintenance of Residential Stormwater Management Areas

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