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Using Model Ordinances and LID Design Guidance Manuals to Overcome Implementation Obstacles. Chris Conway, CPSWQ Lynn Orphan, P.E. Kennedy/Jenks Consutlants Terri Svetich, P.E. Truckee Meadows Storm Water Program Coordinator Central Coast RWQCB Workshop San Luis Obispo - November 18, 2005.
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Using Model Ordinances and LID Design Guidance Manuals to Overcome Implementation Obstacles Chris Conway, CPSWQ Lynn Orphan, P.E. Kennedy/Jenks Consutlants Terri Svetich, P.E. Truckee Meadows Storm Water Program Coordinator Central Coast RWQCB Workshop San Luis Obispo - November 18, 2005 Kennedy/Jenks Consultants
Outline LID Principles & Practices Recommended Policies & Procedures Tools to Promote LID LID Design Considerations Monitoring Program Success
What is LID? Design features and practices distributed throughout urban development that: • Disconnect Impervious Surfaces • Mimic Natural Hydrologic Processes • Reduce Runoff Rates & Volumes • Reduce Pollutant Loads
Evolution of Low Impact Development Pioneered in Maryland 1985 to address economic and environmental issues Applied to western communities such as: Denver, Boise, Phoenix, Los Angeles, San Diego, San Francisco, Portland, and Seattle
The Truckee River Watershed Lake Tahoe to Pyramid Lake Pollutants of Concern Fine Sediment & Lake Clarity TSS, N, P, TDS, Temp, & Turbidity The Truckee Meadows Reno, Sparks, Washoe Co. Rapid Urban Development TMDLs: N, P, TDS Non Point Source Control LID & Public Outreach
Professional Advisory Group (PAG) • Formed in 2004 to develop recommended policies & procedures for implementing treatment controls and LID • PAG Members (Stakeholders): • Developers and Engineers • Builders, Contractors & Landscaping Associations • Community Development, Public Works & Maintenance • Regional Water Planning Commissioners • Environmental Interests
Recommended Policies & Procedures Plan Review & Permitting Construction Inspection Tracking & Maintenance Notification Long-term Operation & Maintenance Inspection & Enforcement Training & Public Outreach
Plan Review and Permitting All projects that will disturb one acre or more: • Require storm water quality and soils information in drainage, hydrology and geotechnical reports • Display treatment controls and LID practices on proposed private and public development site plans • Enforce existing policies to preserve natural drainage ways and groundwater recharge zones • Require standard design criteria • If infiltration proposed, testing required • Apply existing building permit and/or environmental control permit process to storm water BMPs
Construction Inspection • Inspections by environmental control, other agency staff, or the engineer of record during construction • Provide GPS coordinates of completed facilities to the appropriate jurisdiction Tracking and Maintenance Notification Cities and County: • Track the type, location and ownership of treatment controls and LID practices using a GIS • Notify BMP owners maintenance required • Link BMP GIS to County Assessors database
Operation and Maintenance • Require O&M plans that include maps of facilities, define O&M requirements, and responsible parties O&M Responsibility & Funding • Property owners of industrial, commercial and civic (i.e. churches & schools) land uses • City or County for public facilities and residential developments (Not HOAs!) • Maintenance easements and funding mechanisms (i.e. Drainage Districts, Storm Water Utilities, etc.) • O&M by agency staff or maintenance contractor
Inspection and Enforcement Cities and County: • Apply existing legal mechanisms and agency inspection and enforcement procedures • Apply industrial storm water discharge permit classifications to determine inspection frequencies • Adopt City of Reno construction inspection procedure ($100 re-inspection fee)
Training • Develop annual training sessions: • Design training for engineers, planners, landscape architects and agency staff • O&M training for property BMP owners, operators and agency inspection and maintenance staff • Low cost training developed through NWEA and UNCE • Certificate of completion
Public Education & Outreach • Nonpoint Source Education for Municipal Officials (NEMO) • LID Seminars & Workshops • Water Watch by Storm Center
Additional Tools to Promote LID Design examples and standard details Streamline plan review & permitting Egineering tools & financial incentives LID demonstration projects
Standard Design Forms • Blue cells: Designer enters site specific data • Yellow cells: Write protected formulas produce design data
LID vs. Conventional Storm Drainage for a 2 acre Parking Lot 1. Conventional Storm Drain System (catch basins and storm drain pipes)2. Landscape Detention with Underdrains (poorly drain soils, e.g. clayey soils)3. Landscape Detention without Underdrains (well drained soils, e.g. sandy soils)
Conventional Storm Drain System Concrete pipe & mounded landscaping 3 catch basins, 1 manhole, 200’ of 12” RCP, 75’ of 18” RCP 20’ 18” RCP 12” RCP Manhole Catch Basin 200’ 10’ 60’ 420’ Increased flow rate, volume and pollutant loading
Landscape Detention (Bioretention) Physical, Chemical & Biological Processes Reduce Pollutants
Landscape Detention (Bioretention) Source: Center for Watershed Protection
Landscape Detention with 5 Underdrains 1 catch basin, 1 manhole, 75’ of 12” RCP, 670’ of 4” PVC 5 bioretention basins, all with underdrain systems (167 CY engineered soil, 75 CY Type 2 aggregate) Overflow to SD system 20’ Swale Swale Inflow via curb cuts 12” RCP 4” PVC Bioretention & Underdrain 4” PVC 200’ 10’ Inflow & Overflow via curb cuts 60’ 420’
Landscape Detention with 3 Underdrains 1 catch basin, 1 manhole, 75’ of 12” RCP, 410’ of 4” RCP 5 bioretention basins, 3 with underdrain systems (167 CY engineered soil, 75 CY Type 2 aggregate) Overflow to SD system 20’ Swale Swale Inflow via curb cuts 12” RCP 4” PVC Bioretention & Underdrain 200’ 10’ 60’ Inflow & Overflow via curb cuts 420’
Landscape Detention without Underdrains 5 infiltration tests, 1 catch basin, 25’ of 12” RCP 5 bioretention basins with no underdrain system (167 CY eng soil, 74 CY Type 2 aggregate) Overflow to SD system 20’ Swale Swale Inflow via curb cuts Bioretention & Infiltration 200’ 10’ Inflow & Overflow via curb cuts 60’ 420’
LID Cost Comparison 1. Conventional Storm Drain System approx. $31,000 2. Landscape Detention with Underdrain approx. $29,000 to $36,100 3. Landscape Detention without Underdrain approx. $15,000 Landscape detention scenarios reduce pollutant loads by 80 – 90% and retain approximately 4,000 ft3 of storm water runoff onsite = 100% of 5-yr storm
LID Design Considerations Prevent groundwater contamination • Proper siting of infiltration systems essential • Infiltration rates 0.5 to 2.4 in/hr (120 to 25 min/in) • 150 ft or more from drinking water wells • Pretreatment recommended Keep storm water out of crawl spaces • Proper grading • Good ventilation • Foundation Drains Prevent mosquito breeding • No standing water 7 days or more (May - October) • Proper design and maintenance required
Monitoring Program Success • Codes & Ordinances Adopted and Enforced • Standard Design Forms Utilized • LID Demonstration Projects Implemented • Professional Training Established • Public Awareness Increased www.TMstormwater.com