SCMs: Post Construction and After. TOWN of CARY

Transcription

1 SCMs: Post Construction and After

2 SCMs: Post Construction and After Introduction Construction Post Construction SCM Stakeholders Case Studies Questions

3 WATER RESOURCES DEPARTMENT Stormwater Division SW Engineering Manager Billy Lee SW Engineer Dan Clinton Jan Patterson SW Program Analyst Charles Brown SW Field Services Administrator Matt Flynn Sr. SW Engineering Technician Todd Hoefler SW Engineering Technicians Kirk Stafford Jeff Hall Environmental Specialist Eric Kulz

4 Cary s Stormwater Early Program History 1972: Floodplain Ordinance 1985: Sediment & Erosion Control 1990: Stormwater Management Plans 1998: EMC Neuse River Rules 50-foot Riparian Buffers 2000: Floodplain Ordinance Revision No Development in the Floodplain 2001: Ordinance Revision Special Flood Hazard Area Adopted Urban Transition Buffers No platting of lots in floodplain or riparian buffer

5 Stormwater Division Programs Stormwater Division Administration Stormwater Master Plan Programs Floodplain Management Capital Projects NPDES Phase 2 2 Environmental Protection Service Support

6 NPDES PHASE 2 Program NPDES Phase 2 Public Education & Outreach Public Involvement & Participation Illicit Discharge Detection & Elimination Construction Site Runoff Post Construction Site Runoff Pollution Prevention & Good Housekeeping

7 NPDES PHASE 2 Permit History July 1, 2005 NPDES Program Background December 1, 2011 February 17, 2017

8 Construction / Post Construction History Mid 1990 s: Emphasis on constructing SCM s as designed Late 1990 s-2001: Emphasis on O&M for functionality 2001: Neuse River Rules - Nitrogen treatment (Cape Fear Basin included) 2005: Phase 2 TSS Treatment impervious >24% 2007: Transitions to independent inspections by qualified professionals 2009: PE Certification within 30 days of conversion of SCM s 2010: GIS compliance tracking for annual SCM inspects

9 Site Plan Process Plan Submittal Development Review Committee (DRC) Erosion and Sediment Control Plan (Construction) Stormwater Management Plan (Post Construction) Construction Grading permit issued and work starts Paperwork for the SCM initiated Post Construction Final paperwork submitted/inspection of device in final form Certificate of Compliance issued and SCM enters post construction program with annual inspections

10 Construction Program

11 Construction to Post Construction SW Div Oversee the Process S&EC Device to SCM Device

12 Conversion Issues Site is stabile Removal and disposal of sediment Proper volume As Built Permanent stabilization Plantings Paperwork

13 Post Construction Program

14 Post Construction Program Goals Regulate SCM Compliance (private and Town owned) Approved SCM design functional integrity is preserved SCM owner s legal responsibilities are sustained in perpetuity SCMs are maintained in perpetuity and comply with O&M Manual requirements Track progress, deadlines, ownership information, photos, inspection reports

15 SCM s in the Town of Cary 263 Wet Ponds 175 Bioretention Areas 221 Constructed Wetlands 113 Dry Ponds 160 Level Spreaders 41 Grass Swales 52 Sand Filters 58 Underground Detention Systems 9 Proprietary Devices (must be pre-approved by DWQ) 3 Riparian Buffers 4 Plunge Pools 1 Step Pool 10 Scour Hole 1 Permeable Pavement 18 Unregulated 1129 SCMs at 547 sites

16 SCM s in GIS

17 SCM Records SCM files include: Record drawings Site specific Operation & Maintenance Manual Financial security documentation (letters of credit) Previous inspection reports Professional engineer certification (30 days of completion) Certificate of compliance letters

18 Stakeholders Designers (PE, RLA) of SCM Design Certification: initial and annually Modifications Developer RP through Transfer HOA/Developer/Citizens O&M of SCM in perpetuity SCM Contractors Monthly/Quarterly/Annual O&M Annual certification if qualified Town of Cary Compliance Technical assistance Plan Review Construction Post Construction Plan Review Construction ~Post Construction Post Construction Post Construction Plan Review Construction Post Construction

19 Case Studies: How to assess and adapt program

20 Ardmore at Reedy Creek Multiple SCM s and Phases in project SCM s conversion delay Developer turns property over to HOA HOA receives SCM s with improper maintenance

21 Issues Faced and Changes Made Track site conversion On site meeting onsite with Owner and Engineer Punch list Emphasis on maintenance in Certificate of Compliance letter

22 Glencroft Townhomes Townhome project with multiple SCM s Conversions phased Certified by engineer Final walk through Noted SCM failures

23 Issues Faced and Changes Made Bioretention devices media clogged Repair failed Implementation further attempts lacking Ensure engineer of record certifies SCM s Certificate of Compliance issued once SCM is fully functional

24 Park at Langston: Issues Dry Ponds built for detention purposes (5 to 1.5 Acres) Issues with standing water and cattails (HOA complaints to Town) Annexed after development Developer performed maintenance prior to transfer of responsibility to HOA

25 Issues Faced and Changes Made HOA education is key Dry pond function O&M Manual and Maintenance Agreement amended Town staff training for various SCM s function

26 Davis Square Townhome project with two SCM s Bioretention and Wetland SCM s converted and certified by engineer and all paperwork received Site visit performed and had no issues Certificate of Compliance issued

27 Issues Faced and Changes Made HOA complaints within 6 months SCM not turned over by developer to HOA Developer s engineer implemented corrective action Working on remedial action Inform the HOA boards, management companies to address issues prior to taking O&M responsibility Empower the HOA to act.

28 Medcon Ct Subdivision Project completed in 2001 Wet pond serves as the SCM Annual inspection failed Wet pond 70 percent full.

29 Issues Faced and Changes Made HOA -14 retired property owners Offsite drainage with associated and sedimentation Requested Town financing Sediment is an issue after 15 years Provide flexibility in schedule

30 Stakeholder Issues Developer is the HOA typically until a neighborhood near completion Developer and the HOA transfer of property is a private transaction HOA does not know how devices function (pass or fail) SCM is certified and is not meeting design standards HOA is unaware of the cost to maintain devices SCM Contractors over sell services

31 SCM Program Outcomes Town Biannual Workshops for stakeholders Information on design, construction, conversion and maintenance of SCM s Awareness of operation and maintenance manual requirements. Quarterly and/or monthly reports and maintenance services to comply with O&M manual maintenance requirements. HOA s are realizing the value of routine maintenance (Monthly/Quarterly) as necessary to avert larger problems The Town is a resource for owners

32 Questions