Agenda 10/26/2010 Item #10FAgenda Item No. 1 O
October 26, 2010
Page 1 of 8
EXECUTIVE SUMMARY
Recommendation to direct the County Manager or his designee to prepare an appeal to the
proposed FEMA flood maps by authorizing the County's consultant to remodel and
provide more current flood maps for two of the twelve basins at a cost not to exceed
$75,000 and to process the necessary budget amendments.
OBJECTIVE: To prepare and file an appeal to the proposed FEMA flood maps using re-
modeled flood zones.
CONSIDERATIONS: The preliminary flood maps that were released to the public on July 12,
2010 were based on modeling efforts that began in 2004. These efforts were based on ground
elevations using Light Detection and Ranging systems ( LIDAR) flown in 2001 and made
available in 2003. Staff has analyzed the maps and has determined that the more recent 2010
LIDAR flown in 2008 and made available in early 2010 indicates that the 2010 LIDAR appears
to provide ground elevations approximately one foot higher than the 2003 LIDAR. (See attached
LIDAR/FEMA Staff Review document.) Because we are seeing a seemingly consistent
approximate 1 -foot higher elevation in the 2010 LIDAR as compared to the 2003 LIDAR, future
modeling and map revisions are likely to produce a flood surface that is correspondingly
different from that currently produced with the certified 2003 LIDAR. A more detailed
summary of this issue is found in the attached LIDAR/FEMA Staff Review document.
In analyzing the implications of these differences, staff expects a "favorable" condition will
occur for the coastal area with the use of the 2010 LIDAR ground elevations for modeling future
base flood elevations. However, this generalization cannot be made for the inland areas.
Although some inland properties may experience a "favorable" condition, other properties now
proposed to be out of the special flood hazard area may be included in a special flood hazard area
when using the 2010 LIDAR for modeling flood elevations. These properties would therefore
experience an "unfavorable" condition in future map updates.
Staff has outlined several actions for the Board of County Commissioners (Board) consideration
in the attached analysis. When considering the economic and physical risk analysis presented in
the attached report, remodeling the inland riverine basins with the 2010 LIDAR is considered a
priority effort and could be accomplished by mid - February. When assessing the most adverse
risk and economically affected areas, staff recommends that the Golden Gate Main West and
Golden Gate Estates Basins be re- modeled and submitted as an Appeal during the Appeals and
Comment period.
FEMA has established the Appeals and Comment period as an opportunity to review the
preliminary base flood elevations before they become final and to appeal them if they are
believed to be scientifically or technically incorrect. The Appeals and Comment period is a 90-
day time period starting from the date when FEMA publishes its second legal advertisement
notice in a local newspaper. Staff's best estimate of the 2nd notice is mid October to mid -
November thus having the Appeals and Comment period end as late as mid - February.
Agenda Item No. 1 O
October 26, 2010
Page 2 of 8
Staff discussed with FEMA the possibility of delaying the adoption of the flood maps until the
entire County could be re- modeled and re- mapped. FEMA officials stated that they would not
delay the current adoption process and that the County could revise the maps after adoption.
Because we are now aware of the ground elevation discrepancies, staff recommends that we
remodel the two linked basins as noted above which can reflect impacts from both rainfall and
coastal surge where extensive development has occurred since 2001 and propose the new base
flood elevations to FEMA during the Appeals and Comment period in order to have the most
accurate flood maps that we can obtain within timeframe established for the Appeals and
Comment period.
Technical guidance for filing an appeal is published by FEMA and staff will use this as its guide
to file the appeal. The appeal and supporting scientific /technical data is sent to FEMA before the
end of the 90 -day appeal period. FEMA will review the appeal and determine its validity. If
FEMA accepts the appeal, FEMA will then revise the preliminary DFIRM and the revised base
flood elevations will go through the public noticing process for a second time. If FEMA does
not accept the appeal, the County would then submit the information as a map revision request.
Either way, we still need the consultant to re -model and produce new flood elevations, within the
limited area described above, to have the currently proposed flood elevations changed. Staff
anticipates that FEMA will accept the appeal based upon the new topography if it shows these
defined areas of physical map revision are needed to make the DFIRM correct.
It is important to note that the request to appeal the Preliminary DFIRM is intended to address
only two of the twelve basins used to create the Preliminary DFIRM. Map revisions will
eventually be needed for all of the basins prior to the next required update. In order to complete
this work, Staff recommends that a multi -year funding plan is considered through the next annual
budget review. It is also important to consider that these updates are required in order to address
growth related changes to the flood plain. As an alternative to a general fund supported update,
staff will evaluate a fee based substitute funding source for consideration. Staff will continue to
coordinate with FEMA through the adoption period and update the Board periodically as things
progress.
Should the Board defer the update of the two basins, Staff would make every effort to notify
those affected ahead of the DFIRM adoption. Additionally, staff would also disclose this
discrepancy to new permit applications within these basins in order to minimize conflicts with
the maps when they are updated.
FISCAL IMPACT: There is no application fee for filing an appeal. The sole cost will be the
cost of the consultant to re -model and re -map the base flood elevations in two basins. The
County's consultant estimates these basins can be re- modeled, mapped and submitted to FEMA
at an estimated cost of $75,000 and be accomplished within 90 days from the date the County's
consultant receives the notice to proceed. Funds would be appropriated from Fund 111 reserves.
Staff will apply for funding assistance from FEMA.
GROWTH MANAGEMENT PLAN (GMP) IMPACT• There is no GMP impact for this
item.
Agenda Item No. 1 O
October 26, 2010
Page 3 of 8
LEGAL CONSIDERATIONS: This item is legally sufficient for Board action. -JAK
RECOMMENDATION: That the Board direct the County Manager or his designee to:
1. Secure a formal quote from the County's consultant, Tomasello, to re -model the Golden Gate
Main West and Golden Gate Estates basins using the 2010 LIDAR.
2. Have the consultant model these Basins, produce the flood maps and submit the maps as an
appeal during FEMA's Protest, Appeals and Comment period. The total cost shall not
exceed $75,000.
3. Process the necessary budget amendments to accomplish the above
PREPARED BY: William D. Lorenz, P.E., Director, Land Development Services Department,
Growth Management Division — Planning and Regulation
Attachment: 1) LIDAR/FEMA Flood Map Staff Review (09 -18 -2010) with Multi -Basin Map
LIDAR /FEMA Flood Map Staff Review
Agenda Item No. 10F
October 26, 2010
09- 18- 26MA(?a� of 8
QA /QC Conflict Identified
The FEMA Flood zone maps were produced based upon ground elevation data produced from aerial
imagery from 2003 LIDAR (flown 2001). The 2010 LIDAR flown in 2008 and made available in early 2010
indicates that the 2010 LIDAR appears to provide ground elevations approximately one foot higher than
the 2003 LIDAR. Field points independently checked and a very recent analysis by the SFWMD indicates
this as well. Both LIDARs had been certified as being adequate to meet FEMA's mapping criteria. FEMA
does not consider the 1' +/- higher variance as a significant impact to the DFIRM adoption. Collier
County's unique topography contains large areas that are relatively flat which means this variance has a
much more dramatic effect on our modeling.
Flood Map Implications
Because we are seeing a seemingly consistent approximate 1 -foot higher elevation in the 2010 LIDAR as
compared to the 2003 LIDAR, future modeling and map revisions are likely to produce a flood surface
that is correspondingly different from that currently produced with the certified 2003 LIDAR. We expect
that the next FEMA map revision will be in 2015. If the County adopts the current proposed map, staff
believes that the 1' +/- lower elevation may potentially set the corresponding Base Flood Elevation (BFE)
inappropriately low in certain areas. New construction set using these BFEs will likely be at elevations
below the future modeled BFE when the model is rerun using the 2010 certified LIDAR. Staff has
discussed the possible changes to the BFEs with the County's modeling and mapping consultant.
Within the coastal zone, the higher actual elevations could result in flooding depths and corresponding
flood elevations being lowered. Also, the higher ground elevations could have a positive effect by
reducing the inland extent of the velocity zones. However, further inland where the flooding is classified
as riverine, the potential change in flood elevations at a particular location will depend on its proximity
to a canal. Locations close to the canal could see a change to low risk zone whereas locations further
from the canal could see flood elevations increasing corresponding closer to the actual topography
variance.
Economic Impacts
In general, the proposed flood maps show some lowering of flood elevations and lessening of flooding
along the coastal zone thus providing favorable economic impacts along the coastal zone. However, the
proposed maps identify vast areas of special flood hazard areas within the County's inland area that
currently are not in a special flood hazard area. Thus from an economic view, the proposed flood maps
generally provide a positive impact for coastal residents but a negative impact for residents in the inland
areas since many residents in these areas will have to begin purchasing flood insurance where none was
required in the past.
As noted above, the higher ground elevations of the 2010 LIDAR could further reduce the proposed
flood elevations in the coastal zone and thus have even more favorable economic impacts to coastal
residents. For the inland areas, however, we expect to see both positive and negative economic impacts
for properties depending on their location and proximity to canals and control structures.
Risk Analysis
For the coastal zone, the use of the 2010 LIDAR for modeling flood elevations will likely result in maps
that reduce the risk of flooding for coastal properties. Thus a "favorable" condition is expected for the
coastal area with the use of the 2010 LIDAR ground elevations for modeling future flood elevations.
However, this generalization cannot be made for the inland areas. Although some inland properties
may experience a "favorable" condition, other properties now proposed to be out of the special flood
LIDAR /FEMA Flood Map Staff Review
Agenda Item No. 1 O
October 26, 2010
09- 18- 20MQ(tp of 8
hazard area may be included in special flood hazard area when using the 2010 LIDAR for modeling flood
elevations. These properties would therefore experience an "unfavorable" condition in future map
updates.
Inland residents whose properties are in an "unfavorable" condition and who relied on the elevation
information of the currently proposed maps may be required to purchase flood insurance in future map
revisions. More troubling would be the scenario where we actually experience a 1% chance storm and
residents who did not purchase flood insurance because they were above the flood elevation in the
currently proposed maps would then have damages but no insurance. The inland properties therefore
have a greater risk of negative consequences in relying on the flood zone maps using the 2003 LIDAR.
Remodeling the inland basins with 2010 LIDAR would address these adverse impacts. If the DFIRM maps
are adopted using the 2003 certified LIDAR, staff would request that homeowners are notified and
warned to consider purchasing flood insurance if they are within 1' of the BFE and new home permits
require a signed affidavit acknowledging the potential impact of a higher BFE.
Staff Analysis
Because of the timing of the FEMA mapping effort and availability of the 2010 LIDAR, it was decided
early on by FEMA that the mapping effort could not wait for the 2010 LIDAR. FEMA representatives
have stated that the 2010 LIDAR was too late for the mapping effort and that the project was not going
to be delayed to use it. Staff understood that the recent 2010 LIDAR would be a better product than the
2003 LIDAR showing additional development and some elevation differences. Both products did receive
a certification for FEMA map standards. However, the constant 1 -foot difference between the two
products is problematic since it will likely cause a difference in future map revisions as described above.
Our consultant estimates that remodeling the total County based on the 2010 LIDAR and producing the
maps for FEMA review would cost $215,000 — $295,000 (depending on FEMA requirements). This total
effort would require up to 200 days. Staff expects that the end of the Protests and Appeals period to be
mid - February assuming FEMA meets its public noticing requirements mid November. From a timing
perspective, it does not appear to be practical to remodel all of the County using 2010 LIDAR and submit
the revised map within this Protest and Appeals period.
When considering the Economic and Risk analysis presented above, remodeling the inland riverine
basins with the 2010 LIDAR is considered a priority effort and could be accomplished by mid - February.
When assessing the most adverse risk and economically affected areas, staff would suggest that the
Golden Gate Main West and Golden Gate Estates Basins be re- modeled and submitted as a Protest
during the Protest and Appeals period. The County's consultant estimates these specific basins can be
re- modeled, mapped and submitted to FEMA at an estimated cost of less than $75,000 and be
accomplished by mid February.
Options for BCC Consideration
A. No further Funding FY2011:
1. Submit the 2010 LIDAR as a Protest during the 90 -day appeals period
2. If FEMA does not revise the maps, indicate on Building Permits that future map revisions could
result in higher BFEs.
3. Prepare and budget for the next map revision (5 years) as needed.
B. Limited Funding FY2011:
1. Secure a quote from the County's consultant, Tomasello to analyze the effect of the 2010 LIDAR
so that we can re -model using the 2010 LIDAR for selected basins that we can accomplish to
LIDAR /FEMA Flood Map Staff Review
Agenda Item No. 10F
October 26, 2010
09- 18- 28so(tp of 8
submit the map during the Protest and Appeal period. Based on the Economic and Risk analysis
presented above, staff recommends that the Golden Gate Main West and Golden Gate Estates
Basins be re- modeled and submitted as a Protest during the Protest and Appeals period. An
initial assessment from Tomasello would indicate a cost of $50,000 - $75,000 and take 90 days
to complete. (It must be complete for the appeals period and could be used to revise the map
for this area.)
C. Maximum Funding FY2011:
1. For the purpose of the Protest and Appeals period, additional basins could be remodeled as long
as they can be submitted during the period. This requires further cost data from Tomasello.
D. Funding for 2012 and beyond.
1. Depending on the BCC's selection of Options A, B and C, begin map revisions for the remaining
basins to conclude the effort in 5 years. Total modeling costs are estimated to be in the order
of $215,000 - $295,000.
2. Indicate on Building Permits that future map revisions could result in higher BFEs.
Staff Recommendation
Staff recommends that the BCC implement Option B. This will address the properties having the
greatest unfavorable economic and risk impacts at the least cost (approximately $50to $75K).
LIDAR /FEMA Flood Map Staff Review
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Agenda Item No. 1 O
October 26, 2010
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Agenda Item No. 1 O
October 26, 2010
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COLLIER COUNTY
BOARD OF COUNTY COMMISSIONERS
Item Number: 10F
Item Summary: Recommendation to direct the County Manager or his designee to prepare an appeal to the
proposed FEMA flood maps by authorizing the Countys consultant to remodel and provide
more current flood maps for two of the twelve basins at a cost not to exceed $75,000 and to
process the necessary budget amendments. (Robert Wiley, Project Manager, Growth
Management Division)
Meeting Dater 10/26/2010 9:00:00 AM
Prepared By
William D. Lorenz, Jr., P.E.
Director - CDES Engineering Services
Date
Community Development &
Environmental Services
Engineering & Environmental Services
1011412010 2:21:08 PM
Approved By
Nick Casalanguida
Director - Transportation Planning
Date
Transportation Division
Transportation Planning
10/15/2010 9:28 AM
Approved By
Judy Puig
Operations Analyst
Date
Community Development &
Community Development &
Environmental Services
Environmental Services
10/15/2010 10:21 AM
Approved By
Norm E. Feder, AICP
Administrator - Transportation
Date
Transportation Division
Transportation Administration
10/15/2010 2:40 PM
Approved By
OMB Coordinator
Date
County Manager's Office
Office of Management & Budget
10115/2010 3:35 PM
Approved By
Therese Stanley
Manager - Operations Support - Trans
Date
Office of Management &
Budget
Office of Management & Budget
10/15/2010 5:25 PM
Approved By
Jeff Klatzkow
County Attorney
Date
10/18/2010 10:19 AM
Approved By
Leo E. Ochs, Jr.
County Manager
Date
County Managers Office
County Managers Office
10/18/2010 1:15 PM