stormwater quality - appendices...mowing of vegetated and grassed areas may be the costliest routine...

Appendices

A1: Summary of Best Practice Maintenance Systems...................................... 2

A2: Photographs of Constructed Treatments ................................................... 5

A2.1 Retarding Basins........................................................................................ 5

A2.2 Wetlands .................................................................................................... 6

A2.3 Chemical Treatment Pond ......................................................................... 7

A2.4 Sand Filters ................................................................................................ 8

A2.5 Green Roofs............................................................................................... 9

A2.6 Silt Traps.................................................................................................. 10

A2.7 Roadside Bioretention Swales ................................................................. 11

A2.8 Roadside Grass Swales ........................................................................... 12

A2.9 Infiltration Trench ..................................................................................... 12

A2.10 Car park Swales..................................................................................... 13

2.11 Porous Concrete Pavement ..................................................................... 14

A2.12 Permeable Pavement............................................................................. 14

A2.13 Disconnected Downpipes....................................................................... 15

A2.14 Creek Restoration .................................................................................. 16

A2.15 Construction Practices ........................................................................... 17

A2.16 Monitoring Practices............................................................................... 18

DRAFT - Appendix 2005 USA Municipal Engineering Foundation Study Tour

Integrated Stormwater Quality Management – A Value for Money approach for Victorian Councils

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Introduction

The document is an Appendix to a report entitled:

‘Integrated Stormwater Quality Management

A Value for Money approach for Victorian Councils: Appendices’

by Alan West, Team Leader Engineering Design, Kingston City Council

The report is based on a 2005 Study Tour funded by the Municipal Engineering Foundation (Victoria) that involved attending:

• The American Public Works Association (APWA) International Congress held in Minneapolis, Minnesota and;

• A number of meetings with local Councils and consultants across five states in America. The organizations were chosen based on their experience with delivering Best Practice in the area of ‘Water Sensitive Urban Design’.

The aim of my study was investigate current best practice in the United States and compare it the current approach adopted by local government in Victoria. In particular, this report concentrates on reviewing the cost and maintenance issues associated with various water quality practices. Section 10 aims to prioritise my impression of strategies and projects that represent ‘value for money’ to help assist Victorian Local Government departments to shape future water quality related budgets.



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A1: Summary of Best Practice Maintenance Systems The following information has been extracted from the USA’s EPA website outlining best practice for monitoring and maintaining water quality improvement treatments

Siting and Design Considerations Siting and Design Considerations Siting and Design Considerations Siting and Design Considerations

In the case of vegetative or other infiltration BMPs, inspection of storm water management practices following a storm event should occur after the expected drawdown period for a given BMP. This approach allows the inspector to see whether detention and infiltration devices are draining correctly. Inspection checklists should be developed for use by BMP inspectors. The checklists might include each BMP's minimum performance expectations, design criteria, structural specifications, date of implementation, and expected life span. In addition, the maintenance requirements for each BMP should be listed on the inspection checklist. This checklist will aid the inspector in determining whether a BMP's maintenance schedule is adequate or needs revision. Also, a checklist will help the inspector determine renovation or repair needs.

Maintenance ConsiderationsMaintenance ConsiderationsMaintenance ConsiderationsMaintenance Considerations

When considering a maintenance schedule for BMPs to control storm water runoff from construction activities, care should be taken to factor in increased erosion and sedimentation rates for construction sites. Clearing, grading, or otherwise altering the landscape at a construction site can increase the erosion rate by as much as 1,000 times the preconstruction rate for a given site (USEPA, 1992). Depending on the relative amount of disturbed area at a site, routine maintenance might have to occur on a more frequent basis. It is important that routine maintenance and nonroutine repair of storm water and erosion control BMPs be done according to schedule or as soon as a problem is discovered. Because many BMPs are rendered ineffective for storm water runoff control if not installed and maintained properly, it is essential that maintenance schedules are maintained and repairs are performed promptly. In fact, in some cases BMP neglect can have detrimental effects on the landscape and increase the potential for erosion. However, "routine" maintenance such as mowing grass should be flexible enough to accommodate varying need based on weather conditions. For example, more harm than good might be caused by mowing during a drought or immediately after a storm event.



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Effectiveness Effectiveness Effectiveness Effectiveness

The effectiveness of BMP inspection is a function of the familiarity of the inspector with each particular BMP's location, design specifications, maintenance procedures, and performance expectations. Documentation should be kept regarding the dates of inspection, findings, and maintenance and repairs that result from the findings of an inspector. Such records are helpful in maintaining an efficient inspection and maintenance schedule and provide evidence of ongoing inspection and maintenance. Because maintenance work for storm water BMPs (mowing, removal of sediment, etc.) is usually not technically complicated, workers can be drawn from a large labor pool. As structural BMPs increase in their sophistication, however, more specialized maintenance training might be needed to sustain BMP effectiveness.

Cost Considerations Cost Considerations Cost Considerations Cost Considerations

Mowing of vegetated and grassed areas may be the costliest routine maintenance consideration (WEF, 1998). Management practices using relatively weak materials (such as filter fabric and wooden posts) may mean more frequent replacement and therefore increased costs. The use of more sturdy materials (such as metal posts) where applicable may increase the life of certain BMPs and reduce replacement cost. However, the disposal requirements of all materials should be investigated before BMP implementation to ensure proper handling after the BMP has become ineffective or when it needs to be disposed of after the site has reached final stabilization.

More informationMore informationMore informationMore information

More information can be found on the USA EPA website at: http://cfpub.epa.gov/npdes/stormwater/menuofbmps/site_2.cfm EPA Home > OW Home > OWM Home > NPDES Home > Storm Water > Menu Menu of BMPs



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A2: Photographs of Constructed Treatments

A2.1 Retarding Basins

Retarding basin/ passive recreation area catering for a 600 dwelling subdivision

City of Bellevue (15km east of Seattle), Washington State

Retarding basin/ parkland City of Bellevue (15km east of Seattle), Washington State



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A2.2 Wetlands

Wetland / Detention Pond

Ramsey-Washington Metro Watershed District

(5km outside Minneapolis), Minnesota

Wetland / Detention Pond

3 rd Street, City of Griffin (40km SE of Atlanta), Georgia

Wetland / Detention Pond as part of a new subdivision

City of Griffin

(40km SE of Atlanta), Georgia



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A2.3 Chemical Treatment Pond

Detention Pond at Taners Lake



(3 photos)

$600,000 project designed to inject liquid Alum chemical to

remove high phosphorous content in natural soil (to

reduce algae bloom).

Photo shows the building housing the automatic pump

injection system

Photo showing the sump

where the alum mixes with the stormwater



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A2.4 Sand Filters

Large Above Ground Sand Filter City of Bellevue (15km east of Seattle), Washington State

Below Ground Sand Filter consisting of three precast

concrete chambers

Winding Woods Lane Residential Subdivision

Baltimore County, Maryland



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A2.5 Green Roofs

Green Roof – On top of City Hall

City of Seattle,

Washington State

Green Roof – On top of City Hall, City of Atlanta, Georgia Photo on the right shows a typical cross section



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A2.6 Silt Traps

Large Silt Trap protecting downstream creek City of Bellevue (15km east of Seattle), Washington State

Vegetated infiltration swale constructed beside a local street 128th Street Reconstruction Project City of Seattle, Washington State



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A2.7 Roadside Bioretention Swales

Vegetated infiltration swale constructed beside a local street

128th Street, City of Seattle

Washington State

Vegetated Infiltration Trench Maplewood Mall Subdivision,

North St Paul Ramsey-Washington Metro Watershed District, Minnesota

Vegetated swale (‘Rain Garden’) along a local street

Wood Raven Ct, Baltimore County, Maryland

Note: The rain gardens along

this street were removed (filled in with soil) at the request of residents. The above photos

shows the only remaining swale which has been disconnected

from the kerb cut out



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A2.8 Roadside Grass Swales

Grass swale constructed beside a local street 128th Street, City of Seattle, Washington State

Grass swale with infiltration trench constructed beside a main road

City of Bellevue (15km east of Seattle), Washington State

A2.9 Infiltration Trench

Gravel Trench located within apedestrian mall

St. Paul City Square, Minnesota



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A2.10 Car park Swales

Grass swale surrounding Embassy Suites Hotel Carpark City of Bellevue, Washington

State

(2 photos)

Vegetated swale constructed within buffer strips between

bays University of Maryland




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2.11 Porous Concrete Pavement

A2.12 Permeable Pavement

Interlocking Pavers constructed within a residential court bowl McBeth Ct, Ramsey-Washington Metro Watershed District, Minnesota

City of Altanta, Georgia

Porous concrete carpark constructed in 2002

Above: A close up of the rough

surface texture

Porous concrete driveway Southface Energy &

Environmental Resource Centre



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A2.13 Disconnected Downpipes

Downpipes draining across grass reinforced with a 1m wide strip of synthetic mesh placed along flow

path to limit erosion.

Winding Woods Lane, Baltimore County (20km north of Baltimore),

Maryland

Downpipes discharging onto a rockery/ garden beds New subdivision in the



Downpipe discharging into a ‘Rain Barrel’ Southface Energy & Environmental Resource Centre

City of Atlanta, Georgia



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A2.14 Creek Restoration

Existing creek reconstructed to cater for high flows via an underground 100 year pipe and low flows via a meandering creek (shown in the above photos)

Battle Creek Project – $7M Special Charge Scheme

Ramsey-Washington Metro Watershed District (5km outside Minneapolis), Minnesota



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A2.15 Construction Practices

Grate pit insert designed to trap silt during construction of a residential subdivision in the Ramsey-Washington Metro Watershed District


Silt fence protecting downstream grate pit.

Winding Woods Lane

Baltimore County (20km north of Baltimore), Maryland

Rock beaching used to reduce velocities in the swale. Note the

small stones in the front supported by larger rocks behind

Winding Woods Lane




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A2.16 Monitoring Practices

Concrete channel directing runoff from a large carpark into vegetated infiltration swales.

The above photo shows a device used to measure the volume of runoff entering

the treatment area to compare with water quality samples

University of Maryland Baltimore County, Maryland

stormwater quality - appendices...mowing of vegetated and grassed areas may be the costliest routine...

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