Framework for Post-Construction SMP Program Management Presented by: Aaditya Pise, P.E. (JMT) Alan Fody, P.E. (PWD)
Presentation Agenda Overview of Philadelphia Water Stormwater Management Regulations Need for Inspection and Assessment of SMP Inspection and Hydraulic Assessment Elements Inspection Findings and Take-away Discussion
PWD Stormwater Regulations Development projects with 15,000 SF disturbance must manage stormwater onsite and obtain PWD approval 765 projects approved to date PWD inspects during construction to verify SMPs are built per approved plans Record Drawings required at project closeout to confirm as-built conditions Property owners are responsible for longterm maintenance Sites are eligible for credits on their stormwater bill
PWD s Needs Circa 2013 137 sites were constructed from 2006-2010 without Record Drawings and many sites were not inspected during construction Record drawings were needed to verify the installation and performance of the SMPs Maintenance inspections were needed to confirm long-term functionality of the SMPs Verified sites can contribute towards PWD compliance with the CSO Consent Order and Agreement
Inspection and Assessment Assignment Inspection & Hydraulic Assessment of 313 SMPs on 137 sites in the combined sewer area The facilities that were inspected were primarily Underground Infiltration/Detention Systems and Surface Bioretention Water Quality Device Surface Infiltration Basin Surface Detention Basin Surface Biorentention Surface Bioinfiltration Subsurface Infiltration Basin Subsurface Detention Basin Porous Pavement Green Roof SMPs Inspected Under Existing PWD Contract 2 4 12 20 27 30 30 55 118 Cistern 2 0 20 40 60 80 100 120 140
Project Objectives and Goals Record Drawing Creation SMP facilities Drainage Area Hydraulic Assessment Loading Ratio and System Capacity Performance Evaluation Visual Indicators of hydraulic performance Wet-weather Inspection and Verification Performance Grading Maintenance Recommendations
Adaptive Management Delivers Continuous Improvement Opportunities for enhancing operational efficiency and cost effectiveness Protocol enhancement for future phases Lessons Learned & Process Improvement Inspection Planning Protocol and Checklists Plan & Schedule Resource Allocation Site Owner Coordination Record Drawing plans SMP Assessment Report Hydraulic Assessment SMP Grading & Reporting Field Inspections Wet and Dry Weather CCTV, Camera Geophysical/Microgravity Photo log and video documentation
SMP Types Dictate Inspection Techniques Surface SMPs (SWM Planters, Bioretention, Green Roofs, Others) Topographical Survey Visual Inspection Confined Space Inspections Subsurface SMPs (Subsurface Infiltration systems, Proprietary Systems, Others) Topographical Survey Visual Inspection Confined Space Inspections Video/CCTV Inspection GPRS Survey VUSP Pennsylvania Stormwater Symposium, October, 2015
Drainage Area Inspection & Verification Inspection Elements: Visual Inspection Verify DA boundary to SMP Identify areas by-passing SMPs Identify source of trash, debris, sediments within DA Verify all pervious areas have stabilized vegetation Survey DA boundaries and identified bypass areas
Drainage Area Inspection What we like to see:
Drainage Area Inspection What we may see:
Conveyance System Inspection What we like to see: VUSP Pennsylvania Stormwater Symposium October 2015
Conveyance System Inspection What we may see:
Bioretention Inspections What we looked for Verify bioretention bed dimensions Vegetation type and condition Sediment & trash accumulation Outlet structure condition Causes of failures or ineffective operations
Bioretention Inspection What we like to see:
Bioretention Inspection What we may see:
Green Roof Inspection What we looked for Verify system footprint Soil media depth Vegetation type and condition Identify cause of failures
Green Roof Inspection What we like to see:
Green Roof Inspection What we may see:
Subsurface Infiltration System Inspection What are we looking for? Verify basin sizing Verify number of rows of pipe, pipe sizes, and type (perforated, solid). Observe level of clogging and identify source of pollutants (trash, debris and sediments) within the system Observe high-water line within the pipe network Verify size and type of control structures (weir plate, orifice, lowflow control) Invert elevations and dimensions of all system components
Infiltration System Inspection What we would like to see:
Infiltration System Inspection What we may see:
Outlet Structure Inspection What we would like to see:
Outlet Structure Inspection What we may see:
Porous Pavement Inspections What we looked for? Verify pavement footprint Verify drainage area condition and size Estimate percentage of clogged pavement Identify sources of sediment & trash Identify cause of failures
Porous/Permeable Pavement Inspection What we like to see:
Porous/Permeable Pavement Inspection What we may see:
Compliance Reporting & Record Drawings Compliance Report Elements: Site and SMP Description Field Observations Photo/Video Log Inspection Checklists Hydraulic Assessment of SMPs SMP Grading A - System functioning as designed. Regular maintenance required. B - System functioning with minor issues - Regular maintenance required. C - System functioning with major issues - Immediate remediation/maintenance required D - System non-functional - Immediate remediation/maintenance required
Lessons Learned SMPs are not always built as per the approved design plans. Record drawings are key to verifying the SMP performance. Thorough inspection planning is key for elimination conflicts that may arise during field activities Site access, including access to key components of the SMP (control structure) is the prime reasons for delays, or incomplete data collection High-water mark within the control structures and conveyance pipes is a good indicator of the health of SMP.
Lessons Learned Measures such as installing hoods within the conveyance system are effective in preventing debris and floatables from reaching the SMP Consideration should be given to post construction use of the site when designing porous pavement and infiltration facilities. Perfect maintenance cannot make up for installing the wrong type of SMP. Designing for maintenance access is key.
Discussion