Stormwater Management and Infiltration along Central Corridor Light Rail Transit
Stormwater Management and Infiltrationalong Central Corridor Light Rail Transit
Central Corridor LRT Project Overview
University Ave ConstraintsUniversity Ave ConstraintsTight 120’ wide ROWBuildings at ROW lineDensely utilized undergroundzoneRoad and building access to oad a d bu d g access tobe maintained at all times.
University Avenue Today
Current LandLand Use
University Ave Cross Section
Capitol Region Watershed DistrictRequirementsRequirements
Rate control
V l d tiVolume reduction
Water qualityWater quality
City Policies and GoalsTransit oriented developmentTransit oriented developmentEnhanced streetscape & livabilityServe multi modal transportation needsServe multi-modal transportation needsLong-term maintainability
LRT and Roadway Requirements
Required clearances
St i t b d i tStrict subgrade requirements
Required utilities and structuresRequired utilities and structures
Accommodate projected ped & vehicle t ffitraffic
Long-term maintainabilityLong term maintainability
Existing Contamination IssuesExisting Contamination Issues
G d Di lGas and Diesel
Chlorinated SolventsChlorinated Solvents
Heavy Metalsy
Over 10% of the Corridor has limitations due to contamination
Successful Solutions will…
Stakeholder buy-in including City, County, State and Watershed.Combine and overlap facilities to address more than one goal with the same real estategFit within tight CCLRT budgetB i t i bl i t ith t t dBe maintainable in concert with street and LRT operations.
Screening ProcessCompatible with surface and subsurface useCompatible with surface and subsurface useAddress contaminated soils concernsS it bl il ditiSuitable soil conditionsCost effectiveProven performance
Input and review by 8 different consultants and 5 agenciesWorkshop with over 50 participants
Green Practices Screening Process
Screening Results
Infiltration trench with integrated streetscape and storm water conveyanceSump inlets with surface skimmingConvert paved surfaces to perviousConvert paved surfaces to perviousRain gardensSt t l tStormwater plantersInfiltration under side streets
Infiltration
Responds to all 3 watershed goalsResponds to all 3 watershed goals .Could be combined with streetscape and t t dstorm water conveyance needs
Compatible with certain surface and subsurface uses.
Integrated Tree/InfiltrationTree/Infiltration
Trench
Infiltration Trench Details
Infiltration Plan View
Typical Infiltration Trench Profileypical nfilt ation ench ofile
Infiltration Trench
ConstructionStaging
Trees Planted Outside
Infiltration fAreas
Infiltration Section without Trees
Tree Trench withwith
Structural S ilSoil
Street & Median LandscapingSt eet & edian andscaping
Typical Crossing Area
Typical Station Area
Measuring Success
Volume reduction of approx 3 Acre-FeetTreats runoff from 100 acres of pavementAdded over 2000 treesAdded over 2000 treesAdded over 5 acres of new pervious area.Capturing and treating significant water from outside the project limits.
Additional Green Practices
CRWDStormwater PlantersStormwater PlantersRain Gardens
City of St PaulCity of St PaulSide Street Infiltration Trenches
M t C ilMet CouncilRoof collection/re-use from OMF
Thank Youhank ou