Restoring Floodplains in Vermont

Presented by Roy Schiff [email protected]

Acknowledgements Jim MacBroom, Brian Cote, and Jessica Louisos, MMI Mike Kline and Barry Cahoon (ret.), ANR Shayne Jaquith, TNC Dan Monks and RJ Jolly, Town of Bennington Michele Braun and Ann Smith (ret.), Friends of the Winooski River Steve Lotspeich, Town of Waterbury

Lake Champlain Research Conference | January 8‐9, 2018 What is Floodplain Restoration?

(MMI, 2008) (Lars Gange & Mansfield Heliflight, August 31, 2011) (Lars Gange & Mansfield Heliflight, August 31, 2011) Case Study 1 – Railroad Berm Removal (Rural)

(Schiff et al., 2014) Black Creek in Fairfield, VT Photo by S. Pomeroy 2006 Embankment removal along the LVRR Photos by J. Clark 2007/2008 Flood Storage

Re-Connected Floodplain

Limit of Flood

Flood in Fairfield, VT Photo by S. Pomeroy 2008 Design Example Sediment and Nutrient Storage Lamoille Valley Rail Trail

• 200 acres of restored floodplain

• 60,000 cubic yards of fill removed

• 1,400 cubic yards of deposited sediment in 4 storms over 4 floodplains

• 1.3 tons of phosphorus deposited with sediment

• $550,000 project cost PARTICIPATING LANDOWNERS PARTICIPATING TOWNS Mark Boyden, Boyden Valley Farm Bakersfield Dale Cahill, abutting landowner Cambridge Brent Gelineau, abutting landowner Fairfield Tom Howrigan, B&T Black Creek Farm LTD Fletcher Benoit LeRiche, LeRiche Farm Johnson Mark Magnan, Magnan Brothers Dairy, Inc. Wolcott Alan Manchester, Manchester Lumber, Inc. Gavin Ryan, abutting farm‐owner Gary Trudell, Trudell Family Farm

Lamoille County Natural Franklin County Natural Resources Conservation District Resources Conservation District Case Study 2 – Fill/Berm Removal (Village)

Historic Restored Fill Floodplain Roaring Branch Bennington, VT 9/1/2011 Roaring Branch Bennington, VT 9/1/2011 1898 Roaring Branch Flood Damage on Branch Street Bennington, VT Scanned Photograph Courtesy of Town of Bennington ~2 miles

300’

200’ Berm Removal Sediment Attenuation

• Total Power decreases range100-700 W/m2 (948 to 167) • Flood velocity decreases 1-4 feet per second • Flood depth decreases 0.2-1.0 feet • 13 acres of floodplain reconnected to channel • Naturalize process to reduce risk • Reduce need for future channel management • Set community expectations Case Study 3 – Floodplain Park (Village)

Dog Floodplain Northfield, VT Photo by Isaac Maddox‐White 11/13/2017 Floodplain Restoration

• 3 acres of reconnected floodplain

• 2 to 6 feet of fill removal

• 9,000 cubic yards of fill removal

foot of flood reduction Dog Floodplain • 0.5 to 1 Northfield, VT Taken by UVM 11/13/2017 Park Layout and Planting

GPI White River Junction, VT 7/26/2017

Dog Floodplain Northfield, VT Taken by UVM 11/13/2017 Dog Floodplain Northfield, VT 7/27/2017

Dog Floodplain Northfield, VT 8/1/2017

Dog Floodplain Northfield, VT 10/12/2017 Dog Floodplain Northfield, VT 8/1/2017 Dog Floodplain Northfield, VT 10/12/2017 Dog Floodplain Northfield, VT 10/12/2017 Dog Floodplain Northfield,Dog Floodplain VT PhotoNorthfield, by M. VT Braun 10/12/201710/30/2017 Dog Floodplain Northfield, VT Photo by M. Braun 10/30/2017 Case Study 4 ‐ Floodplain Economics

2011 flooding during Tropical Storm Irene (Looking southeast along Main Street.) Source: V. Starinskas, Rutland Herald 1927

2011

Source: MMI, 2013 Hydraulics and Damage Modeling • $51 to $41 thousand reduction in annualized damages

• $2.6 million reduction in simulated damages for a single large flood Design Example Annualized US$

$(60,000) $(50,000) $(40,000) $(30,000) $(20,000) $(10,000) Floodplain

$ ‐ 1A.

xsig2A. Existing $(50,881)

$(40,700)

Elevate

Q100) $(25,562)

Building

Economics (2' $(16,415)

over 2015 buildings 2B. floodprone

Elevate

Existing Q100) $(31,087) Damages

(2'

Waterbury, most

over $(20,694) 2C.

Elevate for Floodplain (Q500) $(26,621)

Existing

utilities

$(22,495) Vermont 3A. floodprone

Remove

Restoration buildings Buildings $(24,924)

most $(16,185) Existing buildings 3C.

Only floodprone

Elevate Q500) $(25,117)

(1'

most

over $(16,185) Floodplain 4A. floodprone buildings

Remove $(11,133)

Restoration

$(6,574) (Schiff

et elevate

al., buildings 4B. floodprone

2015)

Remove $(11,720) essentials

and $(7,222) Floodplain Economics

RANGE OF VALUES FOR ECOSYSTEM SERVICES IN THE FLOODPLAINS OF THE LAKE CHAMPLAIN BASIN

Floodplain Land Cover Low Value 50High yr timespanValue Carbon Storage Carbon Storage NPV per Acre NPV per Acre Class ($/acre/year) ($/acre/year) Low High Low (4.125%) High (4.125%) Agriculture 352 10,808 500 3,605 7,679 224,130 Forest 5,823 6,461 345 19,762 119,176 151,519 Shrubland / Grassland 9,147 9,247 170 315 186,849 189,040 Wetland 5,807 55,870 4,862 84,131 123,389 1,224,428 River 2,119 77,089 ‐ ‐ 43,252 1,572,970 Village Greenspace 2,404 17,919 78 16,129 50,632 392,974 Developed Land Not Valued Not Valued Not Valued Not Valued Not Valued Not Valued

(Earth Economics, 2015)

• $8,500 per acre per year of annual estimated floodplain benefits Floodplain Economics http://www.lcbp.org/wp‐content/uploads/2013/03/78_CostsBenefitsFloodplains.pdf Floodplain Economics

(FEMA, 2013) Thank You

Thorp Brook Photo by R. Schiff 2010 Extra Slides Flood Storage and Land Use Conflicts

(NOAA, 2005) Sustenance

Jordan River Floodplain Photo by R. Schiff 5/20/2008 Floodplain Dimensions

Q100

Q10

QBankfull

Low Low- Low Bench Flow Bench (~Q1) Channel (~Q1)

Bankfull Channel (Q1.5 to Q2)

2- Year Floodplain Colluvium or Ledge 100-Year Floodplain Terrace

River Corridor

FEMA Floodway

(Adapted from Schiff et al., 2014)

Design Dynamic Equilibrium

(Lane, 1955; Rosgen and Silvey, 1996)

Background High‐Energy Floodplains Characteristics

Geomorphic

(Nanson and Croke, 1992) Assessment Mendon Brook Mendon, VT Assessment / Geomorphic Characteristics 9/1/2011 Medium‐Energy Floodplains Characteristics

Geomorphic

(Nanson and Croke, 1992) Assessment Roaring Branch Bennington, VT Assessment / Geomorphic Characteristics 9/1/2011 Low‐Energy Floodplains

Assessment / Geomorphic Characteristics (Nanson and Croke, 1992) Black Creek Bakersfield, VT 1/10/2008 Assessment / Geomorphic Characteristics Source: VT ANR, S. Pomeroy Floodplain Restoration Alternatives Analysis Analysis

2014)

al.,

(Schiff Alternatives Floodplain Restoration Top 10 1. Floodplain confinement and isolation increases risks.

2. Consider floodplain type when evaluating risks and alternatives.

3. No net fill in high and moderate energy floodplains.

4. Recall natural role of floodplains when evaluating alternatives.

5. Consider easily recoverable or nomadic activities in floodplains.

6. Reduce permanent infrastructure in floodplains.

7. Conserve floodplains forever.

8. Floodplain function can be compatible with agriculture.

9. Floodplains can be important recreation assets.

Background 10. Floodplains are the #1 planning consideration for flood resiliency.