Coffee Creek Park Development Low Impact Development (LID)

Coffee Creek Park Development Low Impact Development (LID) City of Duluth, St. Louis County, MN Presented By: Christopher J. Rousseau, P.E. February 27, 2008

Developer / Owner Information Trinity Development Group, LLC Jeffrey Drown Ted Stocke Dan Stocke

Location In the Middle of Everything Away From it All Ted Stocke, Developer City of Duluth, MN 83.68 Acre Development North of Trinity Road (TH 53), east of Anderson Road and south of Quince Street Watersheds Miller Creek to the west and south west and Coffee Creek to the east Adjacent State-Owned Park Land Homes have direct access to recreational trails winding through 175 acres along Coffee Creek to the east

Design Consultant and Partners MSA Professional Services, Inc. Planning, Design, Permitting, and Construction Services Partners: EBI Wetland Delineation EPC Engineering & Testing Geotechnical Alta Survey Company, Inc. Plat Preparation

Professional Services Concept Planning Environmental Assessment Worksheet (EAW) Environmental Site Assessment (Phase I) Alignment Adjustments Plat Requirements Wetlands Permit / Replacement Plan Design and Permitting Construction

Concept Planning January 2005: MSA worked with Trinity Development Group planning layout concept options (one illustration shown)

Environmental Assessment Worksheet (EAW) April 2005: MSA worked with the proposer, Trinity Development Group to present the mandatory EAW, in accordance with EQB (Environmental Quality Board) residential development rule 4410.4300 19B to the RGU (Local Government Unit) City of Duluth

Environmental Site Assessment (Phase I) August 2005: MSA worked with the Trinity Development Group to conduct an appropriate inquiry into the ownership and use of the property with the goal of identifying recognized environmental conditions present in conformance to ASTM Practice E 1527, including 4 components: Records Review search federal and state environmental databases Site Reconnaissance visual and physical site inspection Interviews including property owner and local government officials Report evaluate and document findings, opinions, and conclusions Conclusion: No recognized environmental conditions (RECs) were identified during the assessment

Alignment Adjustments Fall 2005 January 2006: In preparation of working with Alta Survey Company on the plat, MSA worked with Trinity Development Group to collect additional topography information, soil boring logs, and geotechnical data With careful consideration given to the existing wetlands, tree inventory, soil conditions, and City of Duluth requirements, MSA revised the concept plan and prepared preliminary cost estimates for the development

Plat Requirements January 2006 July 2006: MSA worked with the Trinity Development Group, neighborhood residents, Alta Survey Company, City of Duluth, St. Louis County, and the wetlands TEP (Technical Evaluation Panel) to determine plat preparation layout design components: Avoid and minimize wetland impacts to the maximum extent practicable Natural resources conservation (outlots) 300-foot buffer along the north side of Trinity Road (TH 53) 200-foot buffer along the east state-owned Coffee Creek area 50-foot buffers adjacent to existing neighborhoods Additional easements and outlots as required for wetlands, utilities, stormwater BMPs (Best Management Practices), and future housing development (senior housing in 2008) Perimeter trail system and open park space R-3 (all residential type) zoning and special use permit for twin homes (zero lot line setback shared wall) Final Plat 59 Single Family, 54 Twin Homes, and 13 Outlots

Wetlands Permit / Replacement Plan May 2006: The Wetland Delineation Report and approved delineated boundary survey determined that the 83.68 acre development contained 15.21 acres of wetland types 2, 3, 6, and 7 associated with large flow through wetlands and isolated depressional wetlands MSA worked with the Trinity Development Group to minimize impacted areas to the maximum extent practicable by incorporating: Roadway alignment shifting Roadway side slope gabion / rock retaining structures Custom lot grading The final design proposed impacts of 1.12 acres of wetlands. Under the City s Water Resources Management Ordinance and the Wetland Conservation Act, impacted wetlands were replaced at a 1:1 ratio on-site

Wetland Disturbance Map

Wetland Mitigation Overview Map

Wetland Replacement Areas #1 - #3 #1 #2 #3

Design January - October 2006: MSA s team of technical specialists worked with the Trinity Development Group to provide the following major design development tasks: Roadway & right-of-way alignments, profiles, grading Trinity Road (TH 53) special access tier roadway design Special retaining structures Typical section and pavement structure analysis Utilities sanitary sewer, water main, and fire protection Stormwater BMPs (Best Management Practices) SWPPP (Stormwater Pollution Prevention Plan) City of Duluth staff meetings and required plan approval

Design Roadway & Right-Of-Way Alignments, Profiles & Grading Approximately 8,550 lineal feet of 28-foot wide roadway section complete with subsurface drainage, geotextile fabric separation, granular base, aggregate base, concrete curb and gutter, asphalt pavement and adjacent concrete sidewalks per the City of Duluth standards.

Alignment & Grading Plan Sheets

Trinity Road (TH53) Special Access Tier Roadway Design In order to provide access from the south off Trinity Road (TH53) and avoid wetland impacts, MSA designed a switchback separate lane sections for ingress and egress traffic for Coffee Creek Park development On-site blasted granite rock was used to stabilize the inbound roadway side slope to the north MSA worked with Gary Hage, P.E. of EPC Engineering and Testing of Duluth. Gary provided design services for the geotechnical global stability analysis on the 1:1.5 (V:H) slope section

Design Utilities Sanitary Sewer, Water Main & Fire Protection MSA performed a feasibility analysis and determined that the combination of gravity sewer, low-pressure sewer, lift station, and force main were most cost effective for the Developer and the City of Duluth MSA updated the City s water distribution system model to design water main extension and fire protection requirements for the development

Design Low Impact Development Approach to Stormwater Management A Treatment Train approach is being utilized which is intended to capture and treat storm water runoff at the source. By capturing and treating at the source the final BMP storage volume requirements are reduced and time of concentration is increased lowering the peak runoff rates for design storm events. No wetland loss on site by avoiding wetland areas and mitigating/replacing impacted wetland areas at other locals on-site. Natural resources conservation outlots with development plat Stormwater BMPs (Best Management Practices): Encourage Homeowners to Use Rain Barrels for Harvesting Rooftop stormwater runoff for filtering and reuse around outside of home Homeowners Association Shall Require Homeowners to Install Porous Pavers Driveway Approaches Trinity Road Access Median Biofiltration Gallery (11) Boulevard Rain Garden Biofiltration Practices (5) Center Cul-De-Sac Biofiltration Basin Practices (3) Stormwater Management Pond Practices (Wet Pond) (1) Underground Stormwater Management Filtration Gallery

Stormwater Design Requirements Design City of Duluth Dead pool storage volume for 2-½ rainfall event Minnesota Pollution Control Miller Creek is classified as a special water trout stream. o Pending TMDL impairments with temperature and turbidity concerns biofiltration practices recommended o Capture and treat 1 WQ runoff (new impervious) Coffee Creek has no classification for special treatment o Capture and treat ½ WQ runoff (new impervious) o However MSA designed for 1 WQ runoff Flood Control for 10-year and 100-yr storm events Post <= Pre-Development rates after treatment Stormwater BMPs Design Guidance: Reference MPCA Stormwater Manual, 2005, Version 1.0 MN Unified Sizing Criteria Filtration & Bioretention Practices

Trinity Road Access Median Biofiltration Gallery

Rain Garden Biofiltration & Porous Pavers Practices

Center Cul-De-Sac Biofiltration Basin Practices

Wet Ponds & Underground Chambers Filtration Practices

SWPPP (Stormwater Pollution Prevention Plan)

Permits & Approvals

Construction Services Shop Drawing Review Construction Observation Survey Construction Staking and Grade Sheets Meetings Pre-Construction Construction Project Management Correspondence Pay Requests Record Drawings

Construction Photos

Homeowners Association (HOA) Responsibilities Tasks Porous Pavers Biofiltration Galleries/Basins Rain Gardens SWM Ponds Rock Retaining Structures Mulch, Plant & Complete BMP s Inspection Operation Maintenance References Inspection, Operation & Maintenance Manuals Final Plans & Specifications *HOA will complete BMP s once construction up stream has been completed. Engineered media, structures, and piping already installed. HOA will use local nurseries, landscapers & landscape architects to select, place, & install native vegetation.

BMPs Inspections, Operations & Maintenance Homeowners Association

Educating Homeowners to Go Green Composting Rain Gardens Energy Star Appliances Solar Power Hybrid Vehicle Florescent Light Bulbs Water Conservation Vehicle Tune-Ups Phosphorous-Free Fertilizers Biodegradable Garbage Bags Wind Energy Rain Barrels Bicycling & Walking Biofuels Wood or Manure Burner Recycling Carbon Credits Wearing Clothes >1 Time Renewable Home Furnishings Goodwill Donations

Coffee Creek Park Development Low Impact Development (LID) City of Duluth, St. Louis County, MN Presented By: Christopher J. Rousseau, P.E. February 27, 2008