Making LID the preferred and commonly-used approach to site - PowerPoint PPT Presentation

Making LID the preferred and commonly-used approach to site development February 3, 2016 City of Olympia | Capital o f Washing to n State

An Overview of LID for Olympia 1. Olympia’s LID code revision process 2. What is being proposed for City of Olympia 3. Status of that proposal

Olympia’s LID Regulations Permeable Pavements Municipal Code Engineering Design and Drainage Design and Erosion Control Manual Titles 16 & 18 Development Standards

LID Best Management Practices Preserve Native Compost ‐ Amended Minimize Grading Vegetation/Soil Soil Bioretention/Rain Permeable Minimal Excavation Gardens Pavements Foundation

LID Experience ORLA Yauger Park

LID Challenges & Opportunities

Elements Evaluated Gr oup 1: R educ ing Site Distur banc e Gr oup 4: Inc r eased Infiltr ation E le me nt 1: Minimize Site Disturbanc e E le me nt 11: Bio re te ntio n Stre e t Se c tio n E le me nt 2: Re tain and Plant Native Ve g e tatio n E le me nt 12: Sto rmwate rUse o f L andsc aping E le me nt 13: Do wnspo ut I nfiltratio n Syste ms Gr oup 2: Minimize Imper vious Ar ea – E le me nt 14: Pe rme able Paving Sites E le me nt 15: I mpe rvio us Pave me nt with Unde rdrains E le me nt 3: Zo ning Bulk and Dime nsio nal Standards Gr oup 5: Pr oc edur es, Pr oc ess and E le me nt 4: Re stric t Maximum I mpe rvio us Surfac e Codes Co ve rag e E le me nt 5: Re duc e I mpe rvio us Surfac e E le me nt 16: De finitio ns Asso c iate d with On-site Parking E le me nt 17: Ado pt a Ne w Drainag e De sig n and E ro sio n Co ntro l Manual (DDE CM) Gr oup 3: Minimize Imper vious Ar ea – E le me nt 18: L I D Site Asse ssme nt Str eet E le me nt 19: Pre and During Co nstruc tio n I nspe c tio ns E le me nt 6: Minimize Size o f Cul-de -Sac s E le me nt 20: Mainte nanc e Standards and E le me nt 7: Minimize Stre e t Width I nspe c tio ns E le me nt 8: I nc re ase Blo c k Spac ing E le me nt 21: Varianc e s, De viatio ns and E le me nt 9: Re quire Side walks o n Only One Side E xc e ptio ns o f Stre e t Whe re Appro priate E le me nt 10: Minimize Drive way Surfac e E lement 22: Gre e n Ro o fs, Rainwate r Re use , L I D F o undatio ns

Review Participants Permeable Pavements Joint Community Planning and Public Works staff team • Consultants retained by City • Technical Workgroup (architects, engineers, landscape architects, • bankers, foresters, etc.) Interjurisdictional Workgroup • LID Symposium hosted by Northwest EcoBuilding Guild • Citizen Focus Group – selected by City staff • Utility Advisory Committee • Planning Commission • City Council •

LID Public Meetings 2014 and 2015 2014 2015 City Council Land Use & Jan. 23, Nov. 20 June 23, Dec. 10 Environment Committee City Council June 3 Planning Commission Aug. 18 Dec. 7 Utility Advisory Committee May 7, Sept. 3, Oct. 1, Nov. 5, Dec. 3

Administrative Elements Gr oup 5: Pr oc edur es, Pr oc ess and Codes E le me nt 16: De finitio ns E le me nt 17: Ado pt a Ne w Drainag e De sig n and E ro sio n Co ntro l Manual (DDE CM) E le me nt 18: L I D Site Asse ssme nt E le me nt 19: Pre and During Co nstruc tio n I nspe c tio ns E le me nt 20: Mainte nanc e Standards and I nspe c tio ns E le me nt 21: Varianc e s, De viatio ns and E xc e ptio ns

Little or No Change Proposed Gr oup 3: Minimize Imper vious Ar ea – Str eet E le me nt 6: Minimize Size o f Cul-de -Sac s E le me nt 7: Minimize Stre e t Width E le me nt 8: I nc re ase Blo c k Spac ing E le me nt 9: Re quire Side walks o n One o r Bo th Side s o f Stre e t Whe re Appro priate E le me nt 10: Minimize Drive way Surfac e Gr oup 4: Inc r eased Infiltr ation E le me nt 13: Do wnspo ut I nfiltratio n Syste ms E le me nt 15: I mpe rvio us Pave me nt with Unde rdrains lement 22: Gre e n Ro o fs, Rainwate r Re use , E L I D F o undatio ns

Substantive Elements Gr oup 1: R educ ing Site Distur banc e E le me nt 1: Minimize Site Disturbanc e E le me nt 2: Re tain and Plant Native Ve g e tatio n Gr oup 2: Minimize Imper vious Ar ea – Sites E le me nt 3: Zo ning Bulk and Dime nsio nal Standards E le me nt 4: Re stric t Maximum I mpe rvio us Surfac e Co ve rag e E le me nt 5: Re duc e I mpe rvio us Surfac e Asso c iate d with On-site Parking Gr oup 4: Inc r eased Infiltr ation E le me nt 11: Bio re te ntio n Stre e t Se c tio n E le me nt 12: Sto rmwate r Use o f L andsc aping E le me nt 14: Pe rme able Paving

Stormwater Regulations  Flow control (50% of 2 ‐ year storm)  Water quality treatment  Low Impact Development  Compost ‐ amended soils  Roof downspout control (dispersion, infiltration trenches or rain gardens )  Permeable pavements or bioretention for other “hard surfaces”  PERFORMANCE ‐ Any combination of LID BMPs demonstrated with hydrologic modeling to achieve a higher flow control standard (8% of 2 ‐ year storm)

LID Hydrologic Impacts

Minimizing Site Disturbance • Require more info with development applications • Lower thresholds for requiring a grading permit – 7,000 square feet of disturbance, 10 cubic yards of material • Limit ‘mass ‐ grading’ (50% of site, elevation changes no more than 4 feet) • Further limit grading within 100 feet of property boundary • Limit grading near protected areas, e.g., tree tracts, critical areas

Reduce Development ‘Footprints’ • Encourage cottage housing by allowing 50% private parking and 1600 square ‐ foot 2 ‐ story housing • Allow alternative housing forms in ‘planned residential developments’ if 65% soil/vegetation protected & 10% maximum impervious • Continue to allow 4,000 square foot lots, but only allow reduced side yards for lots with alleys • Provide more flexibility in parking lot designs & reduce drive aisle widths, but require appropriate landscaping, limit small spaces to 15%, and prohibit parking that backs onto arterials • Allow senior ‐ housing parking to be half of apartment standard

Retain & Plant Native Vegetation Note: Native vegetation includes both species that occur naturally and species well adapted to current and anticipated environmental conditions. Redefine tree tracts as ‘Soil and Vegetation • Protection Areas’ (SVPA’s) Require SVPA’s in multi ‐ family projects • A minimum of 50% of required open space is • preserved as an SVPA Adopt criteria for plants in SVPA’s, including • percentage of evergreen vs. deciduous trees

Restrict Maximum Impervious Surface Coverage In low ‐ density residential areas, • lower impervious surface to the building coverage limit (about 7/10 of City) In medium ‐ density areas lower • impervious limit by 5 to 10% (about 1/10 of City) Do not change other high ‐ density • areas (about 2/10 of City)

Permeable Pavements Permeable Pavements • Facilitate and encourage the use of permeable pavements on private property (e.g., parking lots, sidewalks, driveways). • Continue to install permeable public sidewalks as feasible throughout the City. Restrict use of permeable paving for streets. • Anticipate increased use of permeable pavement in the future as the technology improves.

Bioretention • PW Transportation considers the use of permeable pavements in public streets to be too great a risk at this time. Therefore, to achieve the LID standard for streets, bioretention swales will be installed instead. • Staff is developing street sections that include bioretention swales within the landscaping strips or median.

Inspection & Maintenance Inspection and Maintenance • Construction inspections to monitor soil compaction and sedimentation • Post ‐ construction inspections to verify facilities are maintained and perform as designed (e.g. permeable pavement unclogged, bioretention draining). • Maintenance of bioretention swales will be a challenge. The SSW Utility proposes to maintain bioretention swales within the right ‐ of ‐ way at a functional level of service. A higher level of service for aesthetics would be the property owner's or HOA's discretion.

Drainage Design and Erosion Control Manual Thresholds for requiring stormwater retrofits with redevelopment • and roadway projects. More conservative methods of determining infiltration rates. • Required testing to verify infiltration facility performance. • “Enhanced” water quality treatment for commercial and multi- • family projects regardless of the proximity to surface waters. Required “Agreement to Maintain Stormwater Facilities.” • Use of bioretention facilities to achieve LID in lieu of permeable • pavements for public streets. Greater guidance for maintenance and pollution source control. •

Next Steps Olympia Planning Commission January 4 & 25 – Briefings • February 1 ‐ Public Hearing • Public Comment Period: January 4 – February 12 • February 22, March 7 and March 21 – Deliberations • City Council Late Spring – Summer 2016 • Revised codes and standards approximately 6 months • prior to Ecology deadline of December 31, 2016