Setback Levees: Hydraulic, Ecologic and Economic Benefits

Tony Melone, PhD, PE, CFM

2011 ASFPM National Conference

Presentation Overview Levee setback concepts Multi-disciplinary approach: going beyond

flood benefits Ecosystem services: putting $$ values to

environmental enhancement Residual risk: planning for extreme events.

180th to 200th Street Levee Setback Study

Soldiers Home Levee Setback Improvement Project

New Setback LeveeFloodplain Reconnectedto River

Levee Setback Concepts

Levee Setback Concepts

Channelized River Channel

Levee Setback Corridor

Ecosystem Services

SEPTEMBER 1, 2010

GREEN RIVERSIDE CHANNEL

POND

GREEN RIVER WETLANDFORESTEDFLOODPLAIN

SIDE CHANNEL LEVEE

LEVEE

GREEN RIVER

LEVEE

A.

B.

C.

A.

B.

C.

TYPICAL SECTION - MINIMUMCORRIDORWIDTH

TYPICAL SECTION - MULTIPLE HABITAT FOOTPRINTS

TYPICAL SECTION - MULTIPLE HABITAT FOOTPRINTS

TYPICAL PLAN - MULTIPLE HABITAT FOOTPRINTS

Ecosystem Benefits - Wetlands

Value = $36,000 per acre per year

Ecosystem Benefits

Floodplain Inundation – 14,500 cfs

Floodplain Inundation – 22,600 cfs

Flood Damage

Avoided Annual Damage

Closing Statement Multi-disciplinary evaluation of levee options

identifies the dollar value of benefits to a community: Flood protection benefits – Avoided damage losses Ecosystem service benefits