North Allston Sub watershed Restoration Plan. Green Infrastructure Concept Plan and Strategies

Transcription

1 North Allston Sub watershed Restoration Plan Green Infrastructure Concept Plan and Strategies

2 Study Area for Green Infrastructure Retrofits

3 Environmental Design Goals for Study Area: Manage stormwater from entire study area through incorporating green infrastructure BMP s Reduce phosphorous loads to the River by 64% Reduce peak flows by 20%; reduce annual runoff volume by 15% Increase evapotranspiration by increasing tree canopy cover and overall vegetation cover in the study area Increase groundwater recharge and infiltrate at least the first inch of runoff from connected impervious cover Improve connectivity between various open spaces and to the Charles River. Implement green street retrofits on existing streets and design new streets with green infrastructure BMP s to treat runoff from both the roadway and sidewalk

4 Priority Sites for Green Infrastructure Retrofits

5 Priority Sites for Green Infrastructure Retrofits Priority Sites Phosphorous s, Removal Efficiencies and Reductions Site Development Status Baseline Phosphorous (lbs/yr) Phosphorous Reduction Efficiency Proposed Phosphorous (lbs/yr) Phosphorous Reduction (lbs/ys) 1 Rena Park Planned % , 11, 12 Greenway + Extension Planned % Barry s Corner Planned % Academic Way Planned % Stadium Way Planned % Hotel/Conference Planned % SEAS Planned % Klarman Hall In Design % Chao Center In Construction % Tata Hall Built % a g Drainage Areas Planned % Total

6 Concept Design for GI on Priority Sites Priority Site Location Greenway North Greenway South Barry's Corner 1 Barry's Corner 2 (2 alternatives) Conference Center (2 alternatives) BMP Type Conceptual Design Underground Pipe 2 36" pipes with 12" crushed stone along length of Greenway (Approximately 1290 ft) Surface Proposed infiltration trench, ft wide along length of Greenway (Approximately 1290 ft) Surface Surface Underground Pipe Surface Underground Pipe Infiltration trench (Approximately 40 ft by 40 ft) Infiltration trench (Approximately 100 ft by 100 ft) 3 36" pipes with 12" crushed stone (Approximately 370 ft) Infiltration trench approximately 55 ft by 55 ft 4 36" pipes with 12" crushed stone (Approximately 120 ft)

7 Long Term Vision Plan Concept Design for Greenway

8 Greenway Concept Design Wet Weather Visualization

9 Harvard IMP Long Term Vision Plan for GI Retrofits

10 Harvard IMP Long Term Vision Plan for GI Retrofits

11 GI Retrofit Strategies for Study Area Priority Sites SS #1A SS #1B SS #2 SS #3 Strategy Site application of Stormwater BMPs Green Streets with Stormwater BMPs Green Streets with Stormwater BMPs Site Application of Stormwater BMPs Site Application of Stormwater BMPs Application Area Harvard Expansion Projects and Potential Drainage Areas Public ROW in Residential Areas Public ROW along Western Ave Private Commercial Sites Long term Harvard Redevelopment

12 Supplemental Strategy 1A: Residential Green Streets Baseline Phosphorus (lbs P/year) Green Street ROW % Converted Proposed Phosphorus (lb/yr) Reduction in Phosphorus (lbs/year) Baseline Phosphorus (lbs P/year) 10% Impervious 34 20% Lots Draining to Green % Streets Impervious 84 40% Pervious 3 50% 82 39

13 Supplemental Strategy 1B: Western Ave.Green Street Baseline Phosphorus (lbs P/year) 9 % Converted Proposed Phosphorus (lb/yr) Reduction in Phosphorus (lbs/year) 20% % % % % 3 6

14 Supplemental Strategy 2: Commercial Parking Areas Baseline Phosphorus (lbs P/year) 48 % Converted Proposed Phosphorus (lb/yr) Reduction in Phosphorus (lbs/year) 10% % % % % 33 16

15 Supplemental Strategy 3: Long term Harvard Campus Baseline Phosphorus (lbs/year) At Grade % Converted Proposed Phosphorus (lb/yr) Reduction in Phosphorus (lbs/year) Baseline Phospho rus (lbs P/year) 10% % 49 9 Impervious % Pervious 8 Buildings 40 40% % % % % % % 24 16

16 Stormwater Quantity Reductions Sub 1 inch 2 Year 10 Year 25 Year 100 Year Watershe Area d EX PR EX PR EX PR EX PR EX PR C C C E F Total Overall Reduction % 6% 4% 3% 2% Stormwater Peak Runoff Rate Reductions (cubic feet per second) Sub 1 inch 2 Year 10 Year 25 Year 100 Year Watershe Area d EX PR EX PR EX PR EX PR EX PR C C C E F Total Overall Reduction % 16% 14% 14% 13% Stormwater Runoff Volume Reductions (acre-feet)