Charlotte-Mecklenburg
Storm Water Services
Little Hope Creek Flooding
Informational Meeting
Marion Diehl Park
October 1, 2009
Meeting Purpose & Agenda


Purpose
 To provide information about localized flooding
 Respond to questions and concerns about flooding
Agenda
 Staff Introductions
 City & County Storm Water Services – program responsibilities
 Staff Overview - Questions/Concerns (15 minutes)
 Round Table Question & Answer (45 minutes)
Staff Introduction

Jennifer Smith, City SWS
 Matthew Gustis, City SWS
 Doug Lozner, City SWS
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Dave Canaan, County SWS
Tim Trautman, County SWS
Robert Billings, County SWS
Bill Tingle, County SWS
Sharon Foote, County PIO
Little Hope Creek Watershed
 City / County
Jurisdiction &
Program
Responsibilities
More flooding recently?

Why does the flooding seem to have gotten
worse since completion of the City Storm
Water Improvement project?
More flooding recently?
South Blvd Phase I (2001)
Included new drainage pipes and a
detention pond at Baylor Drive
Marsh Road (2004)
Included drainage culvert
replacements and upgraded drainage
pipes under roads
South Blvd Phase II (2007)
Included drainage culvert
replacements, channel stabilization &
floodplain benching
Conway/Briabend (est. 2013)
Includes drainage culvert
replacements, channel stabilization,
floodplain benching and 2 detention
ponds
More flooding recently?
 June 7, 2003
Almost a 25-year event with 3.2 inches of rain in 2 hours
 June 7, 2005
Approx. 10-year event with 2.3 of rain in 1 hour
 August 15, 2006
Approx. 100-year event with 5.3 of rain in 4 hours
 May 5, 2009
Approx. 25-year event with 3.4 inches in 2 hours
 August 16, 2009
Approx. 100-year event with 4.3 inches in 2 hours
Impact of New Development?

Is new or re-development increasing the
flooding?
Impact of New Development?

Pre-1978
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1979 to June 2008
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No detention requirements
No water quality requirements
Commercial & Multi-Family sites required to utilize detention for 2- and
10-year storm events
No detention requirements for Single Family sites
No water quality requirements for any development
July 2008 to present


Commercial, Multi-Family & Single-Family sites required to utilize
detention for 10- and 25-year storm events
Water quality requirements through use of Best Management Practices
Impact of New Development?
Approximate Decade of
Development:
• Before 1970: 61%
• 1970-1979: 10%
• 1980-1989: 15%
• 1990-1999: 6%
• 2000-present: 8%
Impact of New Development?

Future Floodplain Mapping
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•
•

Full build-out in the watershed
Used adopted Land Use Plans
New construction must comply with future
floodplain predictions
Little Hope Creek Future
floodplain
0 – 3.5 inches height
difference on maps
Creek Maintenance?

How does the City and County maintain
Little Hope Creek & it’s tributaries?
Creek Maintenance?

City will monitor and remove debris and
sediment as needed.

City is working with a consultant on
repairing the erosion near 4526 Bradbury
and whether or not changes need to be
made on the channel upstream of Bradbury
culvert.

City’s project is a green project and will revegetate.
Creek Maintenance?

County’s creek maintenance policy
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Strike a balance between environmental and flood risk reduction goals
No clear cutting
Remove smaller vegetation in lower ½ of creek (Low flow channel)
Removing plants from stream banks has limited effect on flood heights
County conclusions from recent field walk
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•
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Overall, vegetation is not obstructing the low flow channel
Dumping of grass clippings & woody debris can create blockages
County will selectively spray small vegetation in low flow channel
Creek Maintenance?
Upstream of Montford Culvert
AFTER
BEFORE
Creek Maintenance?
Flood Buyouts?

Why hasn’t the County offered buyouts to
homes along Little Hope Creek like other
areas of Charlotte?
Flood Buyouts?

Mitigation Program & Plans
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Adopted plans 2003
Compared alternatives (buyout, elevation, etc.)
Prioritized Floodprone structures throughout County
Buyouts
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Stretch local funds
 FEMA ~ 75% (grants)
 Local Match >25%
Cost effective (FEMA grants)
Sustained interior flood damage (Local “Quick Buys”)
Flood Buyouts?
Flood Buyouts?

Buyout statistics (2000-2009)
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Little Hope Creek Area
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Over 200 buildings acquired and demolished
Over 400 families removed from the floodplain
1 home acquired in 2003 through local Quick Buy
Homes not cost effective, therefore no FEMA grant funds
50 of 80 homes are high enough to comply with current regulations
Update of Mitigation Plans (2010 and
beyond)
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Began in 2009, finalized in 2010
Updated strategies and prioritization
Reduce Flooding?

What can be done to stop the flooding
along Little Hope Creek?
Reduce Flooding?
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Current City Initiatives
•
Continue to improve the minor system to reduce
roadway and structure flooding
•
Continue to perform downstream analysis to
verify that the minor system improvements do not
impact the major system
•
Evaluate City streets within the floodplain to
determine if improvements can be made without
impacting downstream property owners
Reduce Flooding?

Current County Initiatives
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•
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Selective Channel Maintenance
Routine Creek Inspections
Blockage Removal
Flood Insurance Discounts
Reduce Flooding?
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Planned County Initiatives
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•
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Add automated flood notification for Emergency Responders
Update Flood Mitigation Plan/Strategies
Update Floodplain Maps

No practical solution to stop the flooding

Creeks naturally overflow onto their
floodplain during a heavy rain
Round Table Discussion
Question & Answer
Session