Decision-Support Tools and Databases to Inform Regional Stormwater Utility Development ... ·  · 2015-04-02Inform Regional Stormwater Utility Development in New England Detenbeck,

Decision-Support Tools and Databases to

Inform Regional Stormwater Utility

Development in New England

Detenbeck, N.E.1, A. Morrison2, J. Morgan2, V. Zoltay3, R. Abele4, J. LeClair4, and T. Garrigan4

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, 2015 1

…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

Assessing stormwater runoff

contributions

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

3

*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.

Assess

Data sources for impervious area

in New England

Data

source

Resolution Year(s)

NLCD 30 m 2006, 2011

CT 1m (select watersheds) 2010

MA 1m (statewide) 2005

ME 5m (statewide)

1m (select towns)

2004

2010

NH 30m (Coastal and York County)

1m (organized towns)

1m (select towns)

1990, 2000, 2005, 2010

2003-2007 change

2010

RI 1m (statewide) 2003/2004, 2011

VT 1m (Lake Champlain Basin) 2008, 2011

4

Assess

NLCD vs. Classified 1m NAIP

1m NAIP imagery

Classified 1m NAIP data

30m NLCD data

Assess

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

Simplified Impervious

Cover Analysis

• 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

• $700 for license vs. $$$ for

other more complicated

programs

7

Before Road Data

After Road Data

Assess

New Impervious Cover

estimates in VT and RI

8 ¯(not to scale)

Assess

• Stormwater rebates

• Compliance with MS4 permits

• Best Management Practice (BMP) inventory

for maintenance

• Watershed planning and adaptive

management

9

Why track treated impervious cover? Track

Incentives for Low Iimpact

Developement Installation

10

• 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

Track

* Information collected by

each organization varied

widely in attributes,

details and scale

Data sources for Green Infrastructure

BMPs in New England

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

separator, dry well, or grit

chamber

Street address

Town of Coventry, CT None Street address Connecticut DEEP Site Name, Type of

Installation, None

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

• Procedure:

• Query sources

• Map BMPs

• Determine IA

treated*

• Aggregate IA

treated across

catchments and

watersheds

Track

Aggregate BMPs*

% Treated IC by

watershed

% Impervious Cover (IC) by watershed

*Data will be made available on EPA’s EDM application (www.epa.gov/edm)

Track

Easy strategies for updating a

stormwater BMP inventory

13

California Storm Water Multiple Application and Report Tracking System – SMARTS

Part of online application for Construction Permit Notice of Intent

https://smarts.waterboards.ca.gov/smarts/faces/SwSmartsLogin.jsp

Track

WMOST: Cost-benefit analysis tool for

integrated water resource management

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

Cost-

Benefit

WMOST Optimization Tool

Optimization Capabilities

Output Support

Desired Characteristics

Elements

Generic

Familiar, Accessible Software

Natural hydrologic cycle

Human hydrologic system

Interaction points and

processes

Management practices

Decision support system

Comprehensive & Integrated

Framework

15

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

WMOST Management Practices

16

Cost-

Benefit

Adapted from Limbrunner et al., 2005

Recharge

Recharge

Recharge

Runoff

Recharge

Runoff

Runoff

Runoff and recharge rates:

• Baseline

• Detention pond

• Swale

Generalization of land-use and BMP effects

using Hydrologic Response Units*

HRU 1

*HRU = Combination of land-use and soil type 17

Cost-

Benefit

18

Sources for WMOST runoff

and infiltration time series

Pawtuxet SWAT w CC

NE Coastal SWAT w CC

CT HSPF

Upper Merrimac HSPF

Lake Champlain Basin SWAT

Cost-

Benefit

19

HRU = Hydrologic

Response Unit,

unique combination

of soil type and

land-use

Number of

management

scenarios including

baseline

WMOST Main Screen Cost-

Benefit

Specifying Stormwater Practices

• 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

Costs

• Initial = all inclusive

implementation cost

• O&M = annual upkeep

through lifetime

BMP description

BMP is not permitted on

undeveloped land uses

20

Cost-

Benefit

21

WMOSTv2

HSPF model

output d’base

50-year

climate record FEMA HAZUS

model SOPs

Flooding cost curve

SUSTAIN SWMM

User input: Mgt options

Climate scenario

(avg,dry,wet)

BMP scenarios

Runoff w/out BMPs Runoff w BMPs

- Flow

-Optimal mgt actions

-Avg or current

-Wet

-Dry

- Cost

Runoff

Infiltration

series by HRU

Climate variability module

Flooding module

BMP module

$0

$15,000

$30,000

$45,000

$60,000

$75,000

$90,000

-100 100 300 500

Dam

ag

e C

ost

(th

ou

sa

nd

s o

f d

olla

rs)

Recurrence Interval (years)

Potential Building Damage-Cost

Integration of WMOST with other models Cost-

Benefit

Flood Depth and

Damage Assessment

• 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

Cost-

Benefit

Flood Depth and

Damage Assessment

• Obtain building data

– Building footprints

– Parcel data

– Zoning data

• Input flood depth grid and

building data into HAZUS-

MH

Cost-

Benefit

Flood Depth and

Damage Assessment

• HAZUS output – Thematic maps by census block

– Infrastructure losses

– Site-specific building losses

Cost-

Benefit

Flooding within Plymouth County, MA

Potential Building Damage

10 Year Flood

50 Year Flood

100 Year Flood

500 Year Flood

10-Year Flood Depth Grid

500-Year Flood Depth Grid 100-Year Flood Depth Grid

50-Year Flood Depth Grid

Building Count

Commercial 83

Industrial 27

Residential 657

Total

Buildings 767

Building Count

Commercial 240

Industrial 60

Residential 1476

Total

Buildings 1776

Building Count

Commercial 135

Industrial 39

Residential 937

Total

Buildings 1111

Building Count

Commercial 159

Industrial 48

Residential 1161

Total

Buildings 1368

Cost-

Benefit

26

( Western Kentucky University

Stormwater Utility Survey 2014 )

$0

$10,000

$20,000

$30,000

$40,000

$50,000

$60,000

$70,000

0 100 200 300 400 500

Damage Cost for Residential Structures (Plymouth County)

*thousands of dollars

Average Cost per Residential

Unit= $48,415

Putting costs into context Cost-

Benefit

27

Quantifying benefits of green infrastructure

BMPs provides information to support

public-private partnerships

Cost-

Benefit

Demonstrations can be arranged

GeniePro Impervious Cover Analysis

EDM application data downloads

Watershed Optimization Support Tool +

HAZUS

28

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