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<br />Tuesday, May 19 1 :30 - 3:00 PM Track 8 - Map Determination - Moderator: PeRl1.Y Bowker
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<br />AUTOMATED FLOOD ZONE DETERMINATION APPLICATION IN MECKLENBURG COUNTY, NC
<br />Kurt Olmsted and William R Tingle, P,G,
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<br />Mecklenburg County Storm Water Services (MCSWS) is responsible for administering the NFIP county wide as well as maintaining and
<br />improving the drainage system in the small towns and unincorporated areas of Mecklenburg County. The administration of these programs
<br />requires the maintenance of massive amounts of spatial and numeric data involving many man-hours of effort annually, In order to effectively
<br />manage these programs, MCSWS decided to develop a GIS application which allows the user to easily and quickly access a wide variety
<br />digital maps and associated data to assist in project management and planning, These applications allow the user to quickly access
<br />information concerning flood zone detenninations, storm water engineering projects, land development activity, and water quality and
<br />quantity, The application which provides the greatest time savings and immediate benefit is the flood zone determination application, which
<br />greatly reduces the time and effort required to determine if a building is in or outside of the Special Flood Hazard Area (SFHA). The base
<br />coverages for the application include the county-wide FEMA Q3 maps, GPS elevation certificate database for 2200 structures in or near
<br />the SFHA. a database of Letters of Map Revision, and the street centerline from which addresses are matched (geo-coded) for geographic
<br />tocation, The GPS elevation certificate database includes the exact location and elevation (both lowest floor and lowest adjacent grade) of
<br />virtually all structures located in or near the SFHA' It also includes the address, base flood elevation, tax value, year built and a myriad of
<br />other information associated with each building, A variety of results are available and the application allows for a determination letter and!
<br />or a GPS elevation certificate to be printed or faxed to the requestor. It is estimated that the applic'lion will eventually reduce staff time
<br />required to provide flood zone information by 60-75%. The presentation will include a live computer demonstration of the flood zone
<br />detennination application.
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<br />IDENTIFYING FEMA FLOOD ELEVATIONS BASED ON PROPERTY APPRAISER MAPS IN A GIS ENVffiONMENT
<br />William K Jones, P,E" J. J. Meadows, Michelle Morin
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<br />Efficient response to customer inquiries is a critical role of any government agency. This Quality Customer service approach has been
<br />identified as a top priority for the City of Tallahassee, Florida. The Stormwater Management Division has developed a Geographic
<br />Information System (GIS) application which queries flood-related data stored in a GIS to optimize the handling of customer requests. The
<br />application, written in Environmenlal Systems Research Institute, Inc. 's (ESRI) Arc View and Map Objects software, allows for user-friendly
<br />query of GIS data and mapping, It a1]ows for timely and efficient response to customer inquiries by Stormwater and other City staff. By
<br />zooming into a specific area from general maps, a user may identifY specific properties, The application then queries water resource
<br />information including watershed, streams reach and established flood elevations and provides site specific information to the user. The
<br />application is also used for research prior to pennit application and in-house data request needs, The application began as a simple data
<br />access project including simple calls to existing digital data, The second phase included the addition ofFEMA floodplain data in both
<br />graphic and table form. Several automated functions were also included to simplify the application for users. The final phase includes
<br />posting to the intranetfmternet allowing for direct customer access to the data. This paper details the development process through each
<br />phase, Discussed are choice of software, software customizationlprogramming, as well as management issues. Engineering calculations
<br />required to facilitate the query ofFEMA floodplain elevation data are also addressed. The development process is presented in a manner
<br />designed to provide useful information and ideas for development of similar applications,
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<br />USE OF AUTOMATED TECHNOLOGffiS IN WATERSHED MANAGEMENT PLANNING
<br />Daniel Cook
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<br />With limited manpower and funding, the Lake County Stormwater Management Commission (SMC) is utilizing in-house computer
<br />capabilities and staff technical expertise to save time and money to increase its flexibility to model and display watersheds, The Squaw Creek
<br />Watershed Management Plan will be used as an example of how SMC is currently utilizing automated technology options for watershed
<br />planning purposes. SMC is integrating GIS technology with CAD and the Army Corps HEC-I and HEC-RAS models through a variety
<br />of vendor software packages, Digital mapped information collected includes 2 foot topographic contours, orthophotos, land use and soils,
<br />Stream cross sections, bridge and culvert information and cross-sections were also delivered digital]y, Aerial photo control points were
<br />collected in the field utilizing a Global Positioning System (GPS). Model development for each watershed is following the same course,
<br />ArcView is used to update the land cover using orthophotos as a backdrop with an overlay ofland use and to create the SCS runoff curve
<br />numbers (RCN) needed for the HEC-l model, using a map overlay of hydrologic soil groups with land use. Automated input of stream
<br />cross-section for HEC-RAS and automated HEC-] input will be demonstrated. Stream cross-sections and hydraulic structures are modeled
<br />using HEC-RAS and CAD in the process of delineating the floodplain. Photos collected of the stream channel and structures can be
<br />displayed in Arc View, Final maps are generated in both Arc View and AutoCAD, Our end results include updated floodplain maps and
<br />map depressional storage areas, maps of the location of all water resources, including wetlands and regional detention sites, and identifY them
<br />for preservation, enhancement or restoration. We can then prioritize these areas and determine cost estimates for assisting local governments
<br />in implementing an action plan.
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