light rail green infrastructure: rooting out pollution
LIGHT RAIL GREEN INFRASTRUCTURE: ROOTING OUT POLLUTION CSWEA’S 90TH ANNUAL MEETING ANNA ELERIA, DIVISION MANAGER
Green Line Light Rail
University Avenue (2009)
Stormwater Management Requirements • CRWD rules apply to all projects greater than one acre • 1-inch volume reduction over impervious surfaces • Linear project cost cap $30,000/Impervious Acre
Successful Stormwater Solutions • Satisfy District 1” volume reduction standard • Have multiple stakeholder buy-in - Metropolitan Council, Saint Paul, Ramsey County and CRWD • Combine and overlap facilities to address more than one goal within same property (provide multiple benefits) • Be maintainable with street and light rail operations • “Green” the corridor • Fit within tight budget
Green Infrastructure Practices
Integrated Tree Trench System – Type I ¾-inch to 1 ½-inch Washed, Crushed Angular Granite
12 inch HDPE Perforated Pipe
CU Structural Soil Below Pavers and Sidewalk
Impermeable Membrane along Property Line
Integrated Tree Trench System – Type II ¾-inch to 1 ½-inch Washed, Crushed Angular Granite
12 inch HDPE Perforated Pipe
Impermeable Membrane along Property Line
* Pipes are sloped and include PVC barriers every 25-50 feet depending on grade
Type I Trench –CU Soil, Infiltration Rock
Green Line Practices - By the Numbers • • • • • • • • •
Impervious Surfaces – 103 Acres Volume Reduction Req. = 6.96 ac-ft Volume Reduction Est. = 3.02 ac-ft Achieved 43% of CRWD 1” Standard Cost Cap - $3,099,800 Construction Cost - $3,290,000 6.8 miles of Permeable Pavers 5 miles of Infiltration Trenches 1,200 Trees in CU Structural Soil
Green Line Side Street Green Infrastructure Practices Purpose • Augment stormwater treatment in the Corridor • Demonstrate applicability and effectiveness of other BMPs • Increase awareness of SW management • Incorporate public art
Green Line Side Street Green Infrastructure Practices • Surface green infrastructure practices • On boulevards of side streets adjacent to University Ave. • Coincide construction with LRT construction • CRWD-owned practices in City ROW
Site Screening Process • 3 key criteria - water quality effectiveness, constructability and education value • 15 factors, including - larger footprint available - high treatment volume - good draining, clean soils - avoids conflicts with utilities and trees - education/visibility • High, medium, or low suitability score
Green Line Side Street BMP Design • Drainage area – 0.16 ac to 1.60 ac • 8 sites - infiltration w/sand trenches and drain tile available • One filtration site due to potential contamination • Inlets – sump catch basins or curb cuts w/step down (shallow sumps) • Off-line design to limit erosion • Artistic railings for stormwater planters • Microparks
Pillsbury Street Rain Gardens
Marion Rain Gardens
Oxford Street Stormwater Planter
Green Line RG and SWP Maintenance • Spring and fall cleanups • 1 -2 x mo. inspections • Trash and sediment removal, weeding, mulch additions, and plant replacement • Special tasks – watering, graffiti removal, railing touch up • 14 RGs/SWPs = 6100 sf 12 – 14 site visits $15 - $19K annually • Bioretention – $1 - $2.40/sf • CB cleaning - $300/sump
Maintenance Issues
Lessons Learned • Engage City staff from multiple departments • Consider adjacent site activities and their impacts during design • Consider theft/vandalism/trash in the design • Perform a 2nd site investigation prior to construction • Frequent communication necessary when working adjacent to another project • Expect plant loss in the first year and upwards of 5 years
Partners Metropolitan Council City of Saint Paul Ramsey County Capitol Region Watershed District MN Clean Water Fund
Questions
Green Line Light Rail
University Avenue (2009)
Stormwater Management Requirements • CRWD rules apply to all projects greater than one acre • 1-inch volume reduction over impervious surfaces • Linear project cost cap $30,000/Impervious Acre
Successful Stormwater Solutions • Satisfy District 1” volume reduction standard • Have multiple stakeholder buy-in - Metropolitan Council, Saint Paul, Ramsey County and CRWD • Combine and overlap facilities to address more than one goal within same property (provide multiple benefits) • Be maintainable with street and light rail operations • “Green” the corridor • Fit within tight budget
Green Infrastructure Practices
Integrated Tree Trench System – Type I ¾-inch to 1 ½-inch Washed, Crushed Angular Granite
12 inch HDPE Perforated Pipe
CU Structural Soil Below Pavers and Sidewalk
Impermeable Membrane along Property Line
Integrated Tree Trench System – Type II ¾-inch to 1 ½-inch Washed, Crushed Angular Granite
12 inch HDPE Perforated Pipe
Impermeable Membrane along Property Line
* Pipes are sloped and include PVC barriers every 25-50 feet depending on grade
Type I Trench –CU Soil, Infiltration Rock
Green Line Practices - By the Numbers • • • • • • • • •
Impervious Surfaces – 103 Acres Volume Reduction Req. = 6.96 ac-ft Volume Reduction Est. = 3.02 ac-ft Achieved 43% of CRWD 1” Standard Cost Cap - $3,099,800 Construction Cost - $3,290,000 6.8 miles of Permeable Pavers 5 miles of Infiltration Trenches 1,200 Trees in CU Structural Soil
Green Line Side Street Green Infrastructure Practices Purpose • Augment stormwater treatment in the Corridor • Demonstrate applicability and effectiveness of other BMPs • Increase awareness of SW management • Incorporate public art
Green Line Side Street Green Infrastructure Practices • Surface green infrastructure practices • On boulevards of side streets adjacent to University Ave. • Coincide construction with LRT construction • CRWD-owned practices in City ROW
Site Screening Process • 3 key criteria - water quality effectiveness, constructability and education value • 15 factors, including - larger footprint available - high treatment volume - good draining, clean soils - avoids conflicts with utilities and trees - education/visibility • High, medium, or low suitability score
Green Line Side Street BMP Design • Drainage area – 0.16 ac to 1.60 ac • 8 sites - infiltration w/sand trenches and drain tile available • One filtration site due to potential contamination • Inlets – sump catch basins or curb cuts w/step down (shallow sumps) • Off-line design to limit erosion • Artistic railings for stormwater planters • Microparks
Pillsbury Street Rain Gardens
Marion Rain Gardens
Oxford Street Stormwater Planter
Green Line RG and SWP Maintenance • Spring and fall cleanups • 1 -2 x mo. inspections • Trash and sediment removal, weeding, mulch additions, and plant replacement • Special tasks – watering, graffiti removal, railing touch up • 14 RGs/SWPs = 6100 sf 12 – 14 site visits $15 - $19K annually • Bioretention – $1 - $2.40/sf • CB cleaning - $300/sump
Maintenance Issues
Lessons Learned • Engage City staff from multiple departments • Consider adjacent site activities and their impacts during design • Consider theft/vandalism/trash in the design • Perform a 2nd site investigation prior to construction • Frequent communication necessary when working adjacent to another project • Expect plant loss in the first year and upwards of 5 years
Partners Metropolitan Council City of Saint Paul Ramsey County Capitol Region Watershed District MN Clean Water Fund
Questions
