Stormwater Program Update to McLean Citizens Association

January 21, 2015

Stormwater Drivers

• MS4 Permit

• Bay TMDL

• Other Local TMDLs

• Maintenance of existing facilities

• Public Safety /Emergency Response

• Dam Regulations

• Conveyance Systems

• Dam Safety and Facility Rehabilitation

• Emergency and Flood Response

• Operations

• Stormwater Regulatory Program

• Streams and Water Quality

• Inspect and maintain approximately 1,500 miles of storm sewer

• Investigate storm drainage and flooding complaints

• Maintain inventory of county facilities

Pipe Before Lining

Pipe After Lining

2013:• Inspected 255 miles of pipe and

12,000 structures• Relined/repaired over 19,000 LF

of storm sewer

• Dam certification and regulatory compliance

• Dam inspection and maintenance

• Dredging

2014:• County SWM Facilities: 1749

• Inspected: 486• Cleaned and mowed: 1,355• Maintenance work orders: 3,432

• Private SWM Facilities: 3825• Inspected: 744

Trends

6

• National Flood Insurance Program

Community Rating System (CRS)

• Storm monitoring

2013:• Flood response events: 8 • Snow removal events: 20

• TMDL compliance

• MS4 permit

• 18 permit elements

• 16 Tactical Plans Complete

• 229 Action Items

• Wet and dry weather monitoring

• Annual stream bio-assessments (since 1999)

• Evaluate trends in stream health countywide

2014:• Dry Weather Monitoring:

• Screened: 102 outfalls• 47 wet• 0 required track down

• Benthic Macroinvertebrates:• Sites Monitored: 70

• Fish Community:• Sites Monitored: 23

• Bacteria Monitoring:• Samples Taken: 176

Stream Quality Index

USGS Stream Gage StudyEvaluate long-term

trends in flow, nutrients and sediment

2014:• Streamflow data: 120,000

measurements• Water Quality data: 96,000

measurements• Monthly Grab Samples: 264• Storm Event Samples: 136• 42 manual streamflow

measurements made at the 20 sites to maintain streamflowrating curve

•Rain Barrel Program•Reforestation •Community Outreach & Public Education•Stream clean-ups

• Stormwater Pond Retrofits

• LID Implementation

• Outfall Improvement

• Stream restoration• Area-Wide Drainage

Improvement

http://www.fairfaxcounty.gov/dpwes/stormwater/projects/project_list.htm

http://www.fairfaxcounty.gov/dpwes/stormwater/projects/project_list.htm

Completed Water Quality Projects

7

12

12

1

4

8

2

10 4

2

1

12

Completed Water Quality Projects FY09-14

Number of Projects 83

Acres Treated 9,172

Linear Feet Treated 19,800

Phosphorous Removed

1,262 lb/yr

Nitrogen Removed 3,591 lb/yr

Sediment Removed 277 tons/yr

2

3

1

1

1

Completed Facilities FY09-14 Cost Per Pound of Pollutant Removal

Practices NumberInstalled TP TN TSS

Stream Restoration 21 $ 22,000 $ 20,000 $ 17

Infiltration Swales & Trenches 5 $ 24,000 $ 4,100 $ 146

Pond Retrofits 40 $ 37,700 $ 8,300 $ 192

Soil Compost Amendment 20 $ 108,000 $ 15,200 $ 700

Dry Swales 9 $ 120,700 $ 20,700 $ 732

Bioretention (Rain Gardens) 24 $ 52,400 $ 26,100 $ 925

Pervious Pavement 6 $ 190,300 $ 32,400 $ 1,200

Capital Cost($/lb/yr)

History of Stormwater Funding

$0.0

$5.0

$10.0

$15.0

$20.0

$25.0

$30.0

$35.0

$40.0

$45.0

$50.0

FY05 FY06 FY07 FY08 FY09 FY10 FY11 FY12 FY13 FY14 FY15Operations (General Fund) Fringe (General Fund)Public Works Construction (Fund 308) Operations (Fund 318)Penny Dedication (Fund 318) Operations, Fringe & Contributory (Fund 125)Stormwater Service District (Fund 125)

Stormwater FY15 Budget

(2%) NVSWCD, Occoquan Lab,Towns, $1.0 M

(12%) Stormwater RegulatoryPrograms, $5.5 M

(9%) Dam Saftey and FacilityRehabilitation, $4.5M

(27%) Streams and WaterQuality, $13.2M

(10%) Conveyance Systems,$5.0M

(38%) Operations, $18.1M

(2%) Emergency and FloodResponse, 0.9M

38% Operations

2% NVSWCD, Lab, Towns

2% Emergency & Flood Response

19

Uncontrolled overland

flow leads to …Flooding

Flooding Managed flow

Outfall RestorationLoftridge- Before & After

Drainage Area(acres)

Phosphorous Removal(lbs/yr)

Nitrogen Removal(lbs/yr)

Sediment Removal(tons/yr)

34 11 13 3.8

Outfall RestorationLoftridge- Now





34 11 13 3.8

Outfall RestorationSheffield Hunt– Before & After





29 64 188 25

Stream RestorationSheffield Hunt - Now

Stream RestorationBridal Path - Before & After





162 138 790 132

Stream RestorationDead Run – Before

Stream RestorationDead Run – During & After





415 15 283 2.5

Stream RestorationWolftrap Creek- Before & After





766 90 1,016 172

Fair Woods- Before & After

Area Treated(acres)




26 9 44 0.9

Pond Retrofits

Fair Woods- Now

Area Treated(acres)




26 9 44 0.9

Pond Retrofits

Low Impact DevelopmentSpring Hill RECenter - After

Area Treated(acres)




14 2.5 11.5 0.2

Kings Park West- Bioretention and Reforestation Before





3 5 35 0.3

Low Impact Development

Kings Park West- Bioretention and Reforestation now





3 5 35 0.3


Fred McMath Facility - Bioretention Before & After





1 1 9 0.1


Low Impact DevelopmentNoman Cole WWTP- Before & After

Area Treated(acres)




0.6 0.4 2

Questions?

Stormwater Planning Division 703-324-5500, TTY 711www.fairfaxcounty.gov/dpwes/stormwater

www.fairfaxcounty.gov/dpwes/watersheds

[email protected] County is committed to nondiscrimination on the basis of disability in all county programs, services and activities.

Reasonable accommodations will be provided upon request.

http://www.fairfaxcounty.gov/dpwes/stormwater

http://www.fairfaxcounty.gov/dpwes/watersheds

mailto:[email protected]

Stormwater Program Update to McLean Citizens Association

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