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Anne Kitchell Horsley Witten Group, Inc. April 2, 2014

2014 Decision Makers

Workshops: Construction and

Clean Water

Thinking about Clean Water & Development

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Horsley Witten Group, Inc. Horsley Witten Group, Inc.

Horsley Witten Group, Inc. Horsley Witten Group, Inc.

Horsley Witten Group, Inc. Horsley Witten Group, Inc.

A quick trip to www.savebuzzardsbay.org

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Horsley Witten Group, Inc. Horsley Witten Group, Inc.

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On today’s agenda

• The impacts of development

• Watershed decisions for decisions makers − Where to build − How to build − How to manage

“the built” • What is coming…

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The visible impacts from existing development

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Urbanization results in increased surface runoff

BEFORE AFTER

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Watershed impacts at~10% impervious are well documented:

• Water quality issues • Impacts to biological

communities • Increased flooding • Stream erosion • Loss of recreational uses • Shellfish bed closures • Reduced recharge &

baseflow • Wetland & contiguous

forest loss • Increased % managed lawn

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% Impervious cover is an indicator

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Impervious Cover at the Community Scale

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8-10%

20%

30% > 65%

< 5%

As seen in the stream

% impervious

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Time (hrs)

Runo

ff (c

fs)

Post-development More runoff volume Arrives faster

Pre-development

Runoff Hydrograph

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2 great (but dated) references

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Runoff WQ data from~3,800 storm events, 17 states

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Horsley Witten Group, Inc. Horsley Witten Group, Inc.

Streams with <50 sq miles drainage upstream

0102030405060708090

100

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30

% IC Upstream

% o

f R

efer

ence

C

omm

unit

y

n=125

Meet WQC

Fail WQC

12% IC Threshold

% of Reference Community compares 7 metrics- Taxa Richness, Modified HBI , Scraper/Filterer, EPT/Chironomidae, % Dominant Taxa, EPT Index, Community Loss

Bellucci, CTDEP

Linking the Bugs to IC

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Note: Data averaged from existing Massachusetts Estuaries Project Reports

Contour plots of modeled total nitrogen concentrations (mg/L) in Three Bays.

Source: MEP 2006

Pre-colonial

Present Day Future Buildout

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David Johnson and Kate Morkeski load a device that feeds fertilizer into the salt marsh on Plum Island. BOSTON GLOBE OCTOBER 18, 2012 http://www.mbl.edu/tide/data/

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Horsley Witten Group, Inc. Horsley Witten Group, Inc.

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Watershed Decisions • Where we build

– Land use planning – Land conservation – Buffers for protected areas

• How we build – Site Design – Construction – Stormwater/Wastewater

• How we manage what has been built – Retrofit/Redevelopment – Pollution prevention

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How would you rate your land use planning from a water resource protection perspective?

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How valuable are your local wetlands?

Source: Buzzards Bay Coalition website

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Do you rely on minimal state protections or more stringent local bylaws?

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What are your disturbance thresholds for ESC?

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The problem with how we build

• More and more marginal sites are in play • Not enough consideration for existing site

topography • Lack of respect for native vegetation and

topsoil • Cramming as much on site as possible based

on lot lines and zoning rather than site constraints

• Over-reliance on engineered black boxes

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Conventional LID/New Urbanism

Is consideration of LID required in your local regs?

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Time (hrs)

Runo

ff (c

fs)

Post-development More runoff volume Arrives faster

Pre-development

Runoff Hydrograph

Post-development with detention basins to “match the peak”

Post-development (with LID)

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BMPs used at this site eliminated offsite runoff

Bioretention

Bioretention

Permeable Paver

Infiltration Chambers

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Take a look when its raining…

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Notable Local Porous Asphalt Applications

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Which of these best exhibits the LID spirit?

A B

C D

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Lacey & Arrowhead Lanes

Conventional vs LID?

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GI practices

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Horsley Witten Group, Inc. Horsley Witten Group, Inc.

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How is stormwater managed here?

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cluster layout

Jordan Cove, CT -12 lots clustered on 6.9 acres - Designed to minimize site runoff

Low- mow areas

Bioretention cul-de-sac

grassed swales

pervious & shared driveways Rain gardens

Low Impact Development Does it really work?

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Low Impact Development Does it really work?

Conventional

LID Cluster

Glen Brook Green (Jordan Cove) Research/Demo Project

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Are you settling for last year’s Big Box?

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Grants Block Retrofit - Providence, RI Morris Beacon Design

Are you taking advantage of redevelopment opportunities?

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Cottages on Greene, East Greenwich, RI Union Studio, Morris Beacon Design

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Which wastewater systems are you promoting?

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Horsley Witten Group, Inc. Horsley Witten Group, Inc.

Horsley Witten Group, Inc. Horsley Witten Group, Inc.

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Are PRBs in your future?

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What’s Coming?

• Cape Cod Commission 208 Project • Draft Small MS4 Stormwater Permits for

Massachusetts: – Evaluate development codes for LID barriers – Annual tracking of impervious cover – Retrofit inventory for municipal properties – Program linked to impaired waters – Stormwater standards for entire MS4, not just within wetland

jurisdiction

• Trends in new Stormwater Manuals • Stormwater Utilities? • Local LID by-laws?

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City of Attleboro – Site Design Criteria

A. Use LID measures to the Max Extent Practicable B. Document Planning Process

1. Identify and map critical resources 2. Delineate potential building envelopes that avoid

these resource areas C. Document % Natural Open Space Retained D. Minimize Impervious Surfaces and Document % of

Site Imperviousness E. Disconnect Impervious Surfaces and Document %

of Effective Impervious Cover F. Document Use of Applicable Site Design Features

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How can you require LID??!

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Can we have it all?

• Where to build • How to build • How to manage

what’s been built

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Us at night from space (NASA, 2012)

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Anne Kitchell Horsley Witten Group, Inc. April 2, 2014

2014 Decision Makers

Workshops: Construction and

Clean Water

Thinking about Clean Water & Development

Questions?