Using AGWA and the KINEROS2 Model to Assess Green Infrastructure Designs

Transcription

1 Using AGWA and the KINEROS2 Model to Assess Green Infrastructure Designs D. Phillip Guertin 1, Yoganand Korgaonkar 1, I. Shea Burns 1, Carl Unkrich 2, David C. Goodrich 2, and William Kepner 3 1 University of Arizona 2 USDA-ARS 3 U.S. EPA Funding Provided by the U.S. EPA, Arizona Department of Environmental Quality and National Science Foundation 1

2 Outline Integrated Watershed Management in Arid Built Environments Urban Toolkit in the Automated Geospatial Watershed Assessment Tool (AGWA) Case Studies: La Terraza Subdivision and Prescott Home Lots Conclusions and Future Directions 2

3 Integrated Watershed Management Integrated Watershed Management (IWM) is a comprehensive multi-resource management process, involving all stakeholders within the watershed, who together as a group, cooperatively work toward identifying the watershed s resource issues and concerns. IWM addresses the interrelationships between: Water Supply The Primary Driver in Built Arid Environments Flood Control Water Quality Biological Resources (Natural and Landscaping) Sustainable Communities (Greenness) Social/Economic Issues 3

4 Harvestable Water (Rainwater/Stormwater) - Potential to Augment Water Supply (From: Dr. Evan Canfield Pima County Flood Control) AGWA Urban Toolkit 4

5 Green Infrastructure (GI) Practices The effectiveness of a practice depends on your objective. If your objective is to capture stormwater to mitigate flood and water quality Pervious Surfaces driveways, roads, parking lots are very effective But if your primary goal is to augment water supplies then Water Harvesting Rain Gardens Bio-retention Cells with vegetation, are more effective Need tools that can assess the effect of different combinations of GI practices and evaluate between different development designs. 5

6 AGWA Urban Toolkit Within the KINEROS2 Model Flow Route Delineation routing water down streets or swales Lot Representation potential to uniquely represent each lot Impervious Area Contributing Area Flow Off Flow On Processes Green Infrastructure on Lots Basins Water Harvesting Pervious Surfaces Gray Infrastructure Detention/Retention Ponds Visualization of Results 6

7 Lot Representation Each Home or Commercial Lot can have its own design. Based on the Lot Characteristics (setback, etc.) and GI practices, a lot is broken up into planes with different input parameters. Flow Off Flow On processes can be modeled. Water can be captured and non-contributing areas can be identified. 7

8 La Terraza Subdivision Case Study La Terraza Subdivision in Sierra Vista, AZ (13 ha) Two Events (SCS Type II Design Storm) 10 year Return (34.29 mm; 1 hour) 100 year Return (51.82 mm; 1 hour) Three LID Practices Lot Only Small Retention Basin (1.7 m 3 ; Ks = 201 mm/hr) Pervious Driveway (Ks = 210 mm/hr) Water Harvesting (1.9 m 3 (500 gal) ;Empty) Ten Scenarios No LID Practices Single LID Practice Two LID Practices All Three LID Practices Stream Gauge

9 Results Post-Development Validation (Kennedy et al. 2013) y = 1.02x R 2 = 0.91 y = 1.04x R 2 = 0.92

10 Results 10 Year Return Event Scenario Peak Runoff (m3/s) % Change in Peak Runoff wrt Predevelopment % Change in Peak Runoff wrt Post- Development Pre-development 1.49 NA NA Post-development without LID NA Retention Basin Permeable Pavements Rainwater Harvesting Retention Basin + Permeable Pavements Retention Basin + Rainwater Harvesting Permeable Pavements + Rainwater Harvesting All LID practices

11 Results 100 Year Return Event Scenario Peak Runoff (m3/s) % Change in Peak Runoff wrt Predevelopment % Change in Peak Runoff wrt Post- Development Pre-development 2.92 NA NA Post-development without LID NA Retention Basin Permeable Pavements Rainwater Harvesting Retention Basin + Permeable Pavements Retention Basin + Rainwater Harvesting Permeable Pavements + Rainwater Harvesting All LID practices

12 Visualization of Results Lot and Street Visualization 12

13 Prescott, AZ Case Study Two basic types of lots 1 acre and 0.17 acres Five Rainfall Events 1 hour NOAA Atlas 14 Point Precipitation Frequency Return Depth (in) Depth (mm) 1 year year year year year

14 Case Study: Prescott, AZ Three GI Practices Retention Basin (Ks = mm/hr) Size: 1%, 2%, 5%, 10%, 20% and 30% of lot size Water Harvesting (Empty before event) Size: 50, 100, 250, 500, 1000 and 2000 gallons Pervious Driveway (Ks = mm/hr) Water Quality Loading Factors (from StepL Single Family) Runoff from ICI contributes towards water harvesting DCI modeled as pervious driveway TSS (mg/l) TN (mg/l) TP (mg/l) Retention basin captures runoff before flowing on the street

15 Results 0.17 acre lot Percent change in Runoff as compared to post-development Practices 1 Year Return 2 Year Return 5 Year Return 10 Year Return 25 Year Return Pervious Driveways Water Harvesting 50 Gallons Gallons Gallons Gallons Gallons Gallons Retention Basins (percent of lot size) 1% % % % % %

16 Results 1 acre lot (% change) Percent change in Runoff as compared to post-development Practices 1 Year Return 2 Year Return 5 Year Return 10 Year Return 25 Year Return Pervious Driveways Water Harvesting 50 Gallons Gallons Gallons Gallons Gallons Gallons Retention Basins (percent of lot size) 1% % % % % %

17 Conclusions Retention Basin: Most effective GI practice 5% of lot size resulted in 100% capture of runoff for most events Pervious Driveways: 4 5% runoff capture Water Harvesting: higher percent capture for small rainfall events GI practices were less effective on the large lot Modeling framework works well on developed watersheds Supports the evaluation of different GI designs. Supports the assessment of the cumulative impacts of GI practices. Supports detailed representation and modeling of lot and drainage features on a small catchment. 17

18 Future Research Adding more GI practices and gray infrastructure practices. Improve the hydrological representation of GI practices. Improve the parameterization for GI practices. Impact of time decrease in effectiveness Validation of GI Simulation. Data Sets? HELP! Provide linkages to other software (e.g. SWMM). 18

19 Questions? 19