Creating a water quality credit generating facility and accounting program for MS4 permit compliance flexibility: results of a case study analysis in Orange County, CA Mark Grey, Ph.D Director of Environmental Affairs and Technical Director Building Industry Association of Southern California Construction Industry Coalition on Water Quality (CICWQ) With support from: Daniel Apt & Jeremy Hohnbaum, P.E. Michael Baker International Richard Haimann, P.E., D.WRE Haimann Engineering

Creating a water quality credit generating facility and accounting program for MS4 permit compliance flexibility Regulatory Backdrop Water quality credit generation and use scenarios and spatial relationships Case Study Description to Develop a Water Quality Credit Generating Facility (WQCGF) Routing analysis BMP selection and sizing; performance Cost to construct and maintain

Creating a Water Quality Credit Generating Facility within Orange County -Regulatory Backdrop- -Credit Generation Fundamentals- -Spatial Relationships-

Regulatory Backdrop for LID BMP Alternative Compliance Santa Ana RWQCB: W. Riverside Co., SW. San Bernardino Co., N. Orange Co. Implementing Requirements San Diego RWQCB: Southwest Riverside Co., South Orange Co. Implementing Requirements Order Nos. R9-2013-0001; R9-2015-0001; R9-2015-0100 Water Quality Improvement Plan (WMAA optional) Preparation Water Quality Equivalency Guidance Document (2015) LID AC Program partially “defined” within WQIP-WMAA; Independent ACP locations, for example, may be identified WQIP-WMAA addresses TMDL areas, plus possible focal areas for LID BMPs Order Nos. R8-2009-0030; R8-2010-0033; R8-2010-0036 Section E. Alternatives and In Lieu Programs—Waiver of BMPs “Urban Runoff Fund” and “Water Quality Credit System” allowed with approval from EO Implementing guidance in Orange County Model WQMP (Section 7.II-3.0 – 4.0) and Technical Guidance Document, Appendix I, III, and VI

Credit User = Credit Generator Process for a Priority Development Project to Use LID BMP Alternative Compliance North Orange County Example Alternative Compliance Program Process Flow Chart (Model WQMP Figure 7.II-9) START Remaining design capture volume after LID BMPs implemented to the MEP Does Project Qualify for Water Quality Credits? Water Quality Credits Account for any water quality credits that are applicable to the project. 7.II – 3.1 Yes Credit User No evaluation necessary if Watershed Plan is prepared No Is there still design capture volume remaining after credits applied? Evaluate On-site Treatment Control BMPs Evaluate on-site treatment control BMPs to achieve equivalent level of compliance. 7.II – 3.2 Yes No Would the cost of implementation greatly outweigh the pollution control benefits? Implement On-site Treatment Control BMPs Utilize treatment control BMPs to achieve equivalent level of compliance. 7.II – 3.2 Submit Waiver Request to Regional Board Executive Officer Include documentation of feasibility analysis. 7.II – 3.3 No Yes “Documentation” = City-wide Model WQMP or Watershed Plan Credit Generator Implement Off-site Watershed Based Treatment Control BMPs Utilize off-site treatment control BMPs to achieve equivalent level of compliance. 7.II – 3.2.1 Contribute to Runoff Mitigation Fund Contribute to local/watershed runoff fund to achieve equivalent level of compliance. 7.II – 3.4 Continue WQMP Development Process by Selecting Applicable Source Control BMPs 7.II – 2.4.6

What is water quality credit trading? Water quality credit trading is a method to achieve stormwater (MS4) permit compliance for new and redevelopment projects Credit User Generator Example Area: User Public or private projects which can’t comply with MS4 permit on-site LID retention requirements use water quality credits Generator A project accepts runoff from an adjacent tributary drainage area using a runoff retention facility--installed underground--and the facility generates credits

How would a water quality credit be generated How would a water quality credit be generated? Facility assumptions and performance standards Planning and Design Operations and Maintenance Manage a Design Capture Volume in excess of the facility’s own requirement Demonstrate, through an engineering analysis that facility can feasibly install LID retention BMP appropriately sized to accept runoff from a tributary drainage area Provide assurances that the credit generating facility will continue in perpetuity to accept runoff from the design tributary area Provide BMP operating and maintenance and monitoring assurances Point of Note: Orange County Technical Guidance Document addresses BMP O&M accounting and tracking

Some potential reasons for a priority development project (PDP) to enter into an optional water quality credit trading program: PDP can’t feasibly comply A watershed plan incorporates an LID BMP alternative compliance program PDPs are in areas without POCs or TMDL and a WQCGF is in a TMDL area/watershed Water quality credit generating facility creates multi- benefits, outweighing benefits of on-site PDP compliance Sub-watershed Boundary A & B Receiving Water

Water Quality Credit Generating Facility and Relationship to Tributary Area and Receiving Water Example 1 Tributary Area To Water Quality Credit Generating Facility (WQCGF) Receiving Water Key Assumption: WQCGF must manage DCV of Facility AND Some Portion of Tributary Area DCV Water Quality Credit Generating Facility (WQCGF)

Water Quality Credit Generating Facility and Relationship to Tributary Area and Receiving Water Example 2 Tributary Area To Water Quality Credit Generating Facility (WQCGF) PDP Receiving Water PDP Water Quality Credit Generating Facility (WQCGF) PDP Key Assumption: WQCGF must manage DCV of Facility AND Some Portion of Tributary Area DCV

Water Quality Credit Generating Facility and Relationship to Credit Users PDPs meet minimum on-site performance standard Example 3 B PDP One watershed consisting of two sub-watersheds: A & B PDP Runoff from Users To Storm Drain Tributary Area to Credit Generator PDP Receiving Water A Runoff Sub-watershed Boundary Projects in Watershed B use water quality credits from a Generator facility located in Watershed A A water quality credit generating facility (Generator) is built in sub-watershed A, which is designed to accept all or a portion of sub-watershed A’s tributary drainage area runoff, thus creating “credits” Generator Receiving Water

Water Quality Credit Generating Facility and Relationship to Credit Users Example 4 Tributary Area to Credit Generator B One watershed consisting of two sub-watersheds: A & B Runoff A water quality credit generating facility (Generator) is built in sub-watershed B, which is designed to accept all or a portion of sub-watershed B’s tributary drainage area runoff, thus creating “credits” Generator A PDP PDP PDPs meet minimum on-site performance standard Runoff from Users to Storm Drain PDP Sub-watershed Boundary Projects (Users) in Watershed A use water quality credits generated at a Generator Facility located in Watershed B Receiving Water

Creating a Water Quality Credit Generating Facility within Orange County -Case Study Analysis-

Legacy Campus Plan Project (LCPP) Conceptual Features ~23-acre total new and re-development footprint within City of Orange; Chapman & 55 Medical complex with supporting housing units and commercial and retail space Use consistent with the Chapman Avenue/Tustin Street Land Use Focus Area, and specifically located within the Yorba North Commercial Overlay Adjacent to Santiago Creek, tributary to Santa Ana River 241-acre tributary area east of LCPP

Legacy Campus Plan Project Area and Land Use

Tributary Area to Legacy Campus Plan Project located in Orange, CA

Legacy Campus Plan Project Case Study Storm Drain System

Generation of Water Quality Credits Using LID Retention BMPs LID Retention BMPs Evaluated: Key Criteria for LID BMP Use: Infiltration Basin Infiltration Trench Infiltration Gallery (underground) Biofiltration/Biotreatment Systems Harvest and Use Cistern Combinations of BMPs Size of tributary area relative to facility generating credit Hydraulic line and grade of stormwater runoff delivery to facility from tributary area Soil infiltration suitability/ rate at facility Ponding Depth Depth to groundwater Geotechnical constraints Area-based LID retention BMPs present challenges to accepting runoff from a tributary area greater than facility footprint

LCPP Tributary Area Characteristics and Runoff Volume Volume calculated using OC Model WQMP and TGD standards (85th percentile, 24-hour storm event)

LCPP Tributary Area Characteristics and Runoff Volume Volume calculated using OC Model WQMP and TGD standards (85th percentile, 24-hour storm event)

EXAMPLE Retention BMP which Generates Water Quality Credits: Underground Infiltration Can be located under parking System is made from 96-inch, 16 gage, perforated aluminized type-2 corrugated metal pipe Can be as shallow as 4 feet below ground surface, or deeper

Pollutant Load Reduction Using Regional Stormwater Runoff Retention Results from two case studies in Orange County: Subsurface Infiltration & Flood Basin Retrofit Description Units Campus Legacy Fletcher Basin Tributary Drainage Area Acre 241 918 Average Annual Runoff Acre Feet 154 589 Average Annual Runoff Infiltrated Using Retention 152 267 Average Annual Runoff After Installing Retention 0.82 321 Average Annual Runoff Volume Reduced Percent 98 45

Subsurface Retention System Cost Estimate: Conceptual Project Design – Orange County, CA 48-Inch Diameter System 96-Inch Diameter System Description Cost Capital Construction $13,535,000 Annual O & M $178,000 Total Present Value Capital Cost and O & M over 200 Years $19,454,000 Description Cost Capital Construction $7,835,000 Annual O & M $103,065 Total Present Value Capital Cost and O & M over 200 Years $11,261,000 System sized for runoff from a 241-acre tributary area System located within up to a 5.5-acre footprint ~450,000 cubic feet of runoff (design storm volume)

Subsurface Retention System Cost Estimate: Conceptual Project Design – Orange County, CA 48-Inch Diameter System Description Unit Quantity Unit Price Item Total Engineering   Design Plan and Specifications (7.5% of construction) LS 1 $890,325 $891,000 Permitting and CEQA (20.0% of design) $178,200 $179,000 Subtotal: $1,070,000 Construction Support Construction Administration (5.0% of construction) $593,550 $594,000 Construction Mobilization (1.0% of construction) $117,530 $118,000 Excavation & Stockpile CY 98,238 $9 $885,000 Backfill and Compaction 81,778 $53 $4,335,000 Haul and Dispose of Excavated Soil 16,460 $60 $988,000 Shoring SF 50,461 $15 $757,000 Repaving 193,648 $10 $1,937,000 Diversion Structure at Chapman & Wheeler $235,556 $236,000 Pretreatment Gross Solids Removal Vault $285,556 $286,000 Diversion Pipe to Retention Storage LF 100 $300 $30,000 48" ID Chamber Retention Storage (Corrugated Metal Pipe) 35,366 $65 $2,299,000 Construction Subtotal: $11,871,000 Capital Cost Total: $13,535,000 Annual O & M Cost: 1.5% $178,065 PV O & M Cost: 3.0%, 200 years $5,919,000 Total PV Capital & O & M $19,454,000

Subsurface Retention System Cost Estimate: Conceptual Project Design – Orange County, CA 96-Inch Diameter System Description Unit Quantity Unit Price Item Total Engineering   Design Plan and Specifications (7.5% of construction) LS 1 $515,325 $516,000 Permitting and CEQA (20.0% of design) $103,200 $104,000 Subtotal: $620,000 Construction Support Construction Administration (5.0% of construction) $343,550 $344,000 Construction Mobilization (1.0% of construction) $68,020 $69,000 Excavation & Stockpile CY 54,031 $9 $487,000 Backfill and Compaction 37,571 $53 $1,992,000 Haul and Dispose of Excavated Soil 16,460 $60 $988,000 Shoring SF 37,423 $15 $562,000 Repaving 109,730 $10 $1,098,000 Diversion Structure at Chapman & Wheeler $235,556 $236,000 Pretreatment Gross Solids Removal Vault $285,556 $286,000 Diversion Pipe to Retention Storage LF 100 $300 $30,000 96” ID Chamber Retention Storage (Corrugated Metal Pipe) 8,841 $127 $1,123,000 Construction Subtotal: $6,871,000 Capital Cost Total: $7,835,000 Annual O & M Cost: 1.5% $103,065 PV O & M Cost: 3.0%, 200 years $3,426,000 Total PV Capital & O & M $11,261,000

Findings from Case Study Engineering Analysis Hydraulic line and grade from a tributary area to a Water Quality Credit Generating Facility is an important feasibility & design element Surface-based LID BMPs have limited utility for generating volume credits: May be limited due to routing issues May be limited by design & placement requirements May be limited by available space Underground retention/infiltration systems appear to be most feasible to generate large volume credits Use influenced by LID BMP engineering feasibility criteria Use influenced by location characteristics