• No results found

7 th Annual Technical Conference Georgia Association of Floodplain Management. Legacy Lake Lanier Islands Resort LESSONS LEARNED

N/A
N/A
Protected

Academic year: 2021

Share "7 th Annual Technical Conference Georgia Association of Floodplain Management. Legacy Lake Lanier Islands Resort LESSONS LEARNED"

Copied!
54
0
0

Loading.... (view fulltext now)

Full text

(1)

7th Annual Technical Conference

Georgia Association of Floodplain Management

Legacy Lodge @ Lake Lanier Islands Resort

LESSONS LEARNED

The Flood of September 21, 2009 in Cobb County Georgia

March 28, 2012

Bill Higgins, P.E., CFM

Division Manager - Stormwater Management

Cobb County Water System

(2)

Two Hazard Mitigation Grants were awarded to

Uninc. Cobb Co. following the Sept. 21, 2009 flood:

 One grant for 34 (later amended to 36) properties in Unincorporated Cobb

A second for 16 properties in the City of Powder Springs

..

this presentation will describe our course

prior to and following the award of those grants, and some of the lessons we learned

(3)
(4)

Statistics

794 homes flooded in Unincorporated Cobb

 497 homes with 100-yr floodplain on all or part of property

 297 properties were outside the 100-year floodplain

 112 “Substantially Damaged”  Buyout Grant includes

 35 SD properties in floodplain

 67 SD properties outside floodplain

Some 700 Homes flooded in the City of Austell

100 + Homes flooded in City of Powder Springs

(5)
(6)
(7)

Declarations

 Chairman Sam Olens issued a countywide declaration -Monday evening (9/21/09)

Governor Sonny Perdue issued an Executive Order declaring

a State of Emergency in 17 counties including Cobb -Monday (9/21/09)

 On 9/24/09 President Obama issued a Federal Disaster Declaration for 17 counties

:

Bartow, Carroll, Catoosa, Cobb,

Chattooga, Cherokee, Coweta, Dekalb, Douglas, Fulton Gwinnett, Heard, Newton, Paulding, Rockdale, Stephens, and Walker.

(8)
(9)

History

 In NE Cobb Co, the storm began at 6:30PM on Sunday evening 9/20/2009. The rain ended between 6:30PM and 7:00PM the following day (9/21/2009)

 Community Development and Cobb EMA sent first responders to identify and assist flood victims

 Soon became apparent over a thousand properties had been flooded including hundreds of destroyed homes

 News media was heavily involved interviewing flood victims and government representatives, watching everything and

(10)
(11)

History

 Immediately following the storm:

 Cobb County SWM began visiting dams.

Gregg W. Hudock, P.E. of Golder Associates called offering help. We asked him to help us inspect dams which they did gratis.

Terri Turner, AICP, CFM of GAFM called offering help.

In less than a week Terri obtained commitments from 28

GAFM members to assist Cobb w/ R.S.D.E. damage assessments, which they did gratis

(12)

History

 Terri also identified an individual consultant R.S.D.E. expert,

Ranko Pudar P.E. CFM, to instruct the class

 The R.S.D.E. class was held between October 8 and October 10, 2009 for approximately 70 persons. Mr. Pudar offered this service to Cobb, as well as his subsequent efforts- gratis

 Preliminary Damage Assessments of some 700 properties in Unincorporated Cobb were completed within 1 week.

 By October 21, 2009 (one month after the flood), preliminary R.S.D.E. analyses were completed for all flooded properties in Unincorporated Cobb

(13)

History

 October 21, 2009 - First public meeting held at the Cobb County Fire Station on Austell Road near Clay Road

 We had to deliver some painful messages

 We had no information for City of Austell residents and we could not help them

 Substantially damaged homes within the 100-year floodplain could not be rebuilt without elevating

 Substantially damaged home outside of the 100-year

floodplain would not be deemed eligible to participate in a Hazard Mitigation property acquisition grant

 We would not be able to help everyone

(14)
(15)

History

 Just prior to the October 21, 2009 Public Meeting, Brian McCallum of United States Geological Survey (USGS)

delivered some timely information which was supported by the National Weather Service (NWS).

 The Sweetwater Creek watershed had received 22-inches of rainfall within a 24 hour period which equated to a 10,000 year frequency event.

 The second Public Meeting held on October 26, 2009 went more smoothly.

(16)
(17)

Robert Holmes,

USGS’s National Flood

Program Coordinator stated…

Nationwide, given that our oldest stream gaging records span about 100 years, the USGS does not cite probabilities for floods that are beyond a 0.2 percent probability (500-year) flood.”
(18)
(19)
(20)

History

 From late October until January 10, 2010 we sorted through the flood damaged properties re-assessing and re-checking substantial damage estimates

 On January 10, 2010 we submitted our grant applications

 GEMA processed our applications within a month

 FEMA was halted by the Congressional freezing of the

(21)
(22)

History

 July 31, 2010 Federal Disaster Relief Funds were unfrozen

 Mid-September 2010, Cobb received both grants

(23)

Grant Implementation

 Coordination with GDOT, USACOE, SHPO, USF&WL already done during grant evaluation

 Title Search

 Environmental Assessments

 Phase 1 EA

 Asbestos and Lead Paint

 Close Properties with clear titles (no liens)

 Work to clear titles on upside down properties

 Record Deeds and Deed Restriction

 Procure Demolition Contractor

 Demolish and Remove Structures

(24)

Grant Implementation

 Set up to pay flood victims for the pre-flood value of their property ( home and land not lost contents)

 “Pre-flood Value established by 2009 Tax Appraised Value

in www.cobbassessor.org

 Many received Individual Assistance funds (up to $30K) from FEMA for emergency repairs and temporary relocation

 All previous federal disbursements had to be deducted from sales price as a Duplicate of Benefit (DOB)

(25)

Grant Implementation

A year after the flood, many were upside down with

their mortgages

Some:

 Used their IA relief checks for: food, furniture, clothes, new cars

 Wanted FEMA to cover mortgage payments

 Wanted FEMA to cover lost contents

(26)

Update Sweetwater Creek Floodplain

 Floodplain study for Sweetwater was 23 year old and did not

include this storm in the statistical record.

 Maybe the 100-year floodplain is higher, which could make more victims eligible to participate in Grant

Subsequent study by Jacob, as reviewed by Dewberry

confirmed approx 3-ft higher 100-year floodplain

 Making 33 more home eligible in Unincorporated Cobb and possibly double that number in City of Austell

 FEMA will not deem these homes eligible until Letter of Final Determination issued

 GEMA asserting homes can be made eligible according to premise of “Best Available Data”

(27)

Statistics

The rains returned water levels in the region’s

two largest reservoirs, Lake Lanier and

Allatoona Lake to pre-drought levels:

 Lake Lanier rose by more than 3-ft to Elevation 1068 by September 25th and returned to full pool in October

 Allatoona Lake rose to Elevation 853.25 on September 23, more than 13 feet above flood Pool at Elevation 840.

(28)

Statistics

In Cobb County, the following creeks reached

or exceeded the 500-year frequency event:

 Sweetwater Creek

 Noses Creek

 Noonday Creek

 Butler Creek, and

(29)
(30)
(31)

Statistics

On Sweetwater Creek near Austell…

 High Water Marks showed peak stage of record at 30.8 ft

 Previous peak stage recorded 7/11/2005) from Hurricane Dennis at 21.87 ft.

 Peak Flow (31, 500 cfs) was more than double the previously recorded peak flow of record

(32)
(33)
(34)

Statistics

On the Chattahoochee River, the USGS gage

at Vinings recorded…

 A Peak Stage of 28.12 feet

 Peak Discharge of 40,900 cfs

(35)
(36)

Lessons learned – the ugly truth

-

20 inches of rainfall in less than 24 hours

(37)
(38)

Lessons learned – the ugly truth

Rather than accept the inevitable

consequences of a natural disaster, human

nature compels many people to get

(39)
(40)

State Route 41

@ Butler Creek

(41)
(42)

Lessons learned –“the ugly” truth…

Many expect local government to act as the

(43)
(44)

Lessons learned –“the ugly” truth…

After a flooding disaster the public could care

less about:

…how much it rained; or

…what frequency the rain event was; or

…how saturated the ground was; or

…how many culverts became clogged; or

…whether or not they should have had flood

insurance

All they want to know is…

(45)
(46)

Lessons learned – “the ugly” truth…

Many

…living in the floodplain still do not have flood

insurance

…do not understand what the FEMA floodplain

(47)
(48)

Lessons learned – “the ugly” truth…

Many

…private Dam Owners do not understand or do

not accept what their individual responsibilities

are…

(49)
(50)

Lessons learned – “the bad”…

 The Computed 100-year Floodplain Elevations for Sweetwater Creek were 23 years old.

 After Hurricane Dennis in 2005 a notification to buy flood insurance should have been sent or published.

 Dam Owners should have been put on notice about their dam’s potential hazard to the public

The role of Government with regard to uninsured flooded

homes and existing dams needs clarification

 The SWM Ordinances need work:

 Substantially Damaged homes

(51)

Lesson learned - the good…

 28 GAFM volunteers appeared and helped for a week  RSDE inspections were completed within 1 week

 RSDE assessments completed within 1 month

 No dams failed

 GAEPD Safe Dam’s Program

 Storage Volume Purchase program

 Development Standards

 No one’s home included in previous buyouts flooded  USGS Continuous Gage Network –allowed tracking

 Alliances with U.S.G.S.,USACOE, GAFM & GEMA  USGS: Gage Network & Storm Freq Estimates

 USACOE: Field Surveyed High Water Marks

 GAFM : 28 Volunteers for Damage Assessments

(52)

Progress to Date

 In the 34 (later amended to 36) property grant for Uninc. Cobb (HMGP 1858-0013):

 32 properties closed

 3 properties withdrawn

 1 property closing pending

 29 homes of the 32 closed demolished

 3 homes designated as historic sites by SHPO not yet released for demolition

(53)

Progress to Date

 In the 16 property grant for the City of Powder Springs (HMGP 1858-0014):

 12 properties closed, demolished and removed

(54)

THE END

…. GEMA Home Buyout – Hopkins Road Perpetual Green Space (after demolition)
in www.cobbassessor.org

References

Related documents