Decision-Support Tools and Databases to Inform Regional Stormwater Utility Development in New England

Transcription

1 Decision-Support Tools and Databases to Inform Regional Stormwater Utility Development in New England Detenbeck, N.E. 1, A. Morrison 2, J. Morgan 2, V. Zoltay 3, R. Abele 4, J. LeClair 4, and T. Garrigan 4 1 U.S. Environmental Protection Agency, Atlantic Ecology Division, Narragansett,RI 2 ORISE interns at US EPA Atlantic Ecology Division 3 Abt Associates, Inc., Cambridge, MA 4 US EPA Region 1, Boston, MA March 25,

2 Our Decision Support Tools & Databases Assess stormwater contributions: Cost-effective methods for assessing impervious cover at the parcel scale Track progress: New England database of green infrastructure stormwater BMPs Analyze Costs and Benefits: EPA s Watershed Management Optimization Support Tool (WMOST) Putting co-benefit estimates to good use: potential partnerships 2

3 Assessing stormwater runoff contributions Assess Types of Utility Fee Structures Currently in Use ( Western Kentucky University Stormwater Utility Survey 2014 ) Equivalent Residential Unit* Fixed Rate Tier System Residential Equivalence Factor (some use Intensity Development Factor based on % impervious area) Two Level System (Residential/Commercial) Fee Per Parcel Area Water Meter Unique Fee By Water Usage *An Equivalent Residential Unit (ERU) is usually the average impervious area on a single family residential parcel, although some communities define it as the average of all residential parcels. Fees for non-residential properties are proportional to the ratio of the parcel impervious area to the ERU. 3

4 Data sources for impervious area in New England Assess Data source Resolution Year(s) NLCD 30 m 2006, 2011 CT 1m (select watersheds) 2010 MA 1m (statewide) 2005 ME NH 5m (statewide) 1m (select towns) 30m (Coastal and York County) 1m (organized towns) 1m (select towns) , 2000, 2005, change 2010 RI 1m (statewide) 2003/2004, 2011 VT 1m (Lake Champlain Basin) 2008,

5 NLCD vs. Classified 1m NAIP Assess 30m NLCD data 1m NAIP imagery Classified 1m NAIP data

6 Simplified Impervious Cover Analysis Developed a cost-effective protocol using readily available 4-band NAIP* data Supervised classifications in GeniePro Uses genetic algorithms to incorporate texture, shape, and proximity into traditional spectral inputs Provide training pixels using paintbrush tool, can edit large areas quickly and easily * National Agricultural Imagery Program Assess 6

7 Simplified Impervious Cover Analysis Assess Pre-processing in ArcGIS Add in NDVI and LiDAR Intensity Bands (where available) Post-processing in ArcGIS Add in ancillary E911 Road data Site scale can be classified in minutes Before Road Data $700 for license vs. $$$ for other more complicated programs 7 After Road Data

8 New Impervious Cover estimates in VT and RI Assess 8 (not to scale)

9 Why track treated impervious cover? Track Stormwater rebates Compliance with MS4 permits Best Management Practice (BMP) inventory for maintenance Watershed planning and adaptive management 9

10 Incentives for Low Iimpact Developement Installation Track MassDEP gives credits that allow reduction or elimination of traditional BMPs used to treat and infiltrate stormwater. Credits given for: directing runoff from roads and driveways to vegetated open areas directing rooftop runoff to landscaped or undisturbed areas, preserving open space with a conservation restriction 10

11 Data sources for Green Infrastructure BMPs in New England Track Procedure: Query sources Map BMPs Determine IA treated* Aggregate IA treated across catchments and watersheds * Information collected by each organization varied widely in attributes, details and scale Source Type of data provided Locational Data 319 Grants Description of project Maps, description of location ARRA Description of project Maps, description of location BWSC Type of installation (oil Street address separator, dry well, or grit chamber Town of Coventry, CT None Street address Connecticut DEEP Site Name, Type of None Installation, Green Roof Database Area of green roof Street address International BMP Database Type of Installation Latitude/longitude of installation MA UIC Facility Name Street Address MA MS4 Description of project Maps, description of location ME UIC Description of project Street address ME MS4 Description of project Maps, description of location NEMO Type of Installation Street Address NH UIC Facility Name Latitude/longitude of installation and Street Address New Hampshire Alteration of Natural Terrain Permits Area disturbed, Impervious Area, Undisturbed Area, Length of roadway, Name of Receiving Water, Type of treatment Polygon Shapefile RI UIC Facility Name Street Address RI MS4 Description of project Maps, description of location UNH Stormwater Database Type of Installation Street Address Vermont Water Quality Database Impervious Area, Impervious Area Treated, Name of Receiving Water, Type of treatment Latitude/longitude of installation

12 Aggregate BMPs* Track % Impervious Cover (IC) by watershed % Treated IC by watershed *Data will be made available on EPA s EDM application (

13 Easy strategies for updating a stormwater BMP inventory Track California Storm Water Multiple Application and Report Tracking System SMARTS Part of online application for Construction Permit Notice of Intent 13

14 WMOST: Cost-benefit analysis tool for integrated water resource management Cost- Benefit WMOST facilitates integrated watershed management at the municipality scale by asking, What is the optimal set of actions to achieve water quantity related management goals at least cost? Municipalities can Select Goals: Meet demand for water or wastewater services Achieve minimum and/or maximum in-stream flows to reduce flooding risks/costs Protect fish communities WMOST Functions Support Management Decisions: Screen management actions/practices for water and water-related resources within a watershed context for an optimal mix Provide insight on costs, benefits and trade-offs 14

15 WMOST Optimization Tool Cost- Benefit Elements Natural hydrologic cycle Human hydrologic system Interaction points and processes Desired Characteristics Comprehensive & Integrated Framework Management practices Optimization Capabilities Familiar, Accessible Software Decision support system Generic Output Support 15

16 WMOST Management Practices Cost- Benefit Stormwater with up to 15 practices evaluated Land conservation Demand management via pricing and direct measures such as rebates and incentives Change use of existing infrastructure Increase capacity of existing infrastructure Repair infrastructure Build new infrastructure Interbasin transfer of water or wastewater Infrastructure = gw and sw pumping, water treatment, wastewater treatment, water reuse, aquifer storage and recharge 16

17 Generalization of land-use and BMP effects using Hydrologic Response Units* Cost- Benefit Runoff Runoff and recharge rates: Baseline Detention pond Swale HRU 1 Runoff Recharge Recharge Recharge Runoff Recharge *HRU = Combination of land-use and soil type Adapted from Limbrunner et al.,

18 Sources for WMOST runoff and infiltration time series Cost- Benefit Lake Champlain Basin SWAT NE Coastal SWAT w CC Upper Merrimac HSPF CT HSPF 18 Pawtuxet SWAT w CC

19 WMOST Main Screen Cost- Benefit HRU = Hydrologic Response Unit, unique combination of soil type and land-use Number of management scenarios including baseline 19

20 Specifying Stormwater Practices Cost- Benefit Add a managed land use set for each practice Practice = structural BMP, multiple structural BMPs, LID (e.g., lower IS), LID + BMP Feasible land area BMP description Costs Initial = all inclusive implementation cost O&M = annual upkeep through lifetime BMP is not permitted on undeveloped land uses 20

21 Damage Cost (thousands of dollars) Integration of WMOST with other models Climate variability module 50-year climate record HSPF model output d base User input: Mgt options Climate scenario (avg,dry,wet) BMP scenarios Runoff w/out BMPs Runoff Infiltration series by HRU Flooding module FEMA HAZUS model SOPs Flooding cost curve WMOSTv2 Runoff w BMPs $90,000 $75,000 $60,000 $45,000 $30,000 $15,000 $0 Cost- Benefit Potential Building Damage-Cost Recurrence Interval (years) - Flow -Optimal mgt actions -Avg or current -Wet -Dry - Cost SUSTAIN BMP module SWMM 21

22 Flood Depth and Damage Assessment Cost- Benefit Determine flood elevations along stream reaches User-defined options FEMA Flood Information Study (FIS) profiles and flood elevations Elevation data Input into ArcGIS Subtract surface elevations from flood elevations Compute flood depth grid

23 Flood Depth and Damage Assessment Cost- Benefit Obtain building data Building footprints Parcel data Zoning data Input flood depth grid and building data into HAZUS- MH

24 Flood Depth and Damage Assessment Cost- Benefit HAZUS output Thematic maps by census block Infrastructure losses Site-specific building losses

25 Flooding within Plymouth County, MA Potential Building Damage Cost- Benefit 10-Year Flood Depth Grid 50-Year Flood Depth Grid Building Count Building Count Commercial 83 Commercial 135 Industrial 27 Industrial 39 Residential 657 Residential 937 Total Buildings 767 Total Buildings Year Flood Depth Grid 500-Year Flood Depth Grid Building Count Building Count Commercial 159 Commercial 240 Industrial 48 Industrial 60 Residential 1161 Residential 1476 Total Buildings 1368 Total Buildings 1776

26 Putting costs into context Cost- Benefit $70,000 Damage Cost for Residential Structures (Plymouth County) *thousands of dollars $60,000 $50,000 $40,000 $30,000 $20,000 $10,000 $ Average Cost per Residential Unit= $48,415 ( Western Kentucky University Stormwater Utility Survey 2014 ) 26

27 Quantifying benefits of green infrastructure BMPs provides information to support public-private partnerships Cost- Benefit 27

28 Demonstrations can be arranged GeniePro Impervious Cover Analysis EDM application data downloads Watershed Optimization Support Tool + HAZUS [email protected] 28