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EXECUTIVE SUMMARY

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EXECUTIVE SUMMARY Powered By Docstoc
					           Hennepin County, Minnesota
           FEMA DFIRM Conversion
           2005                                                 Task 15 – Summary Report



                       HENNEPIN COUNTY, MINNESOTA
                         FEMA DFIRM CONVERSION
                                  2005

               TASK 15 - SUMMARY REPORT and QA/QC REVIEW

1.0      INTRODUCTION

This Summary Report details the processes used to create, capture, and QA/QC Base Map
and Flood Hazard information for the Hennepin County, Minnesota DFIRM activity. This
report is to be delivered in accordance with Task 15 – Preliminary DFIRM and FIS Report
Distribution. Black & Veatch has incorporated the Preliminary Digital Data Flood Insurance
Rate Map (DFIRM) table structure for the Hennepin County flood maps. Along with this
report, Black & Veatch is also providing the following information to FEMA.

     Digital maps in PDF format
     Revised DFIRM Mapping and Database Files:
         DFIRM mapping files created and populated in accordance with the requirements
         listed in Guidelines and Specifications for Flood Hazard Mapping Partners.
     Revised Metadata describing the DFIRM data in FGDC format

This information can also be downloaded from the MIP on the K drive at:
R05\MINNESOTA_27\HENNEPIN_27053\HENNEPIN_053C\MICS_30393\Mapping

2.0      PROJECTION OF DATA

         2.1    HORIZONTAL PROJECTION

         The data obtained has been reviewed by Black & Veatch for accuracy, completeness,
         and topological consistency. The GIS data was delivered to Black & Veatch in CAD,
         geodatabase and shapefile format. The GIS base map was comprised of data obtained
         from various sources. The non-revised flood hazard information was extracted by
         Black & Veatch from the effective Flood Insurance Rate Maps (FIRMs) and the
         Flood Insurance Studies (FISs) completed for Hennepin County, MN in 2004. All
            Hennepin County, Minnesota
            FEMA DFIRM Conversion
            2005                                                     Task 15 – Summary Report



        base map and flood hazard data has been projected to a Universal Transverse
        Mercator (meters) Zone 15 coordinate system.

        2.2      VERTICAL PROJECTION

        A vertical projection of National Geodetic Vertical Datum of 1929 (NGVD29) has
        been assigned to all non-revised and revised flood hazard information.

3.0     SUMMARY OF DATA AND QA\QC PROCEDURES

        3.1      DATA SUMMARY

        3.1.1    TOPOLOGY

        The draft DFIRM database was developed in ArcGIS 8.3 in order to utilize the
        topology capabilities of the geodatabase. The following topology rules were enforced
        during QA/QC of Base Map and Flood Hazard features and tables:

             Checked for non-continuous line surfaces and disconnects.
             Checked to ensure that road and floodplain relationship overlaid seamlessly in all
              non-revised areas.
             Checked all database layers for slivers, overshoots, undershoots, B-splines,
              curves, arcs, and other potential inconsistencies.
             Checked the alignment of boundaries between polygons and continuity of features
              between panels.
             Ensured coincidence between features that shared the same boundary.
             Ensured that lines were single part and only crossed at a split junction.
             Ensured that polygons did not overlap and lines did not self-overlap.

        3.1.2    BASE MAP and FLOOD HAZARD TABLES

        Annotation
        Annotation for non-revised areas was created from Microstation drawings that were
        used to produce the 2004 effective FIRM. The annotation was converted to a
        geodatabase annotation feature class at a scale of 1:6,000 or 1:12,000; depending on

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        the map scale of the FIRM panel. The non-revised annotation was updated based on
        internal review and feedback from communities and other agencies. Annotation for
        revised areas was produced in accordance with Appendix K of FEMA’s Guidelines
        and Specifications for Flood Hazard Mapping Partners. An annotation file is not part
        of this deliverable

        S_BFE
        BFEs for all non-revised areas were provided to Black & Veatch in a shapefile by the
        FEMA NSP (Michael Baker Jr.). The BFEs for non-revised areas were created from
        Microstation drawings that were used to produce the 2004 effective FIRM. BFEs for
        revised areas were developed from interpolating elevations at whole foot intervals
        between cross section or node locations.

        S_FIRM_Pan
        FIRM panel polygons were provided in a polygon shapefile by the FEMA NSP. The
        panel scheme is identical to the previous countywide FIRM.

        S_Fld_Haz_Ar*
        A digital file of the 1 and 0.2-percent-annual-chance floodplain boundary delineations
        for non-revised areas of Hennepin County was provided by the NSP in shapefile
        format. Revised areas were delineated from modeling software. XP-SWMM was
        used to model the Nine Mile Creek and Minnehaha Creek watersheds. The Lower
        Minnesota River was modeled using Hec-Ras. Following topology and quality
        checks, the polygon feature table was then populated in accordance with FEMA’s
        Guidelines and Specifications for Flood Hazard Mapping Partners.

        S_Fld_Haz_Ln*
        The S_Fld_Haz_Ln spatial table was developed from the S_Fld_Haz_Ar spatial table
        and attributes were populated accordingly. Topology rules were established to ensure
        that the S_Fld_Haz_Ar and S_Fld_Haz_Ln spatial tables were coincident.

        * Black & Veatch was not involved with the modeling of the revised flood hazard
        areas and therefore makes no claims to the accuracy of the floodplain boundaries.
        Black & Veatch was only involved with incorporating the delineated 1 and 0.2-



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        percent-annual-chance floodplain boundaries in to the DFIRM database and
        preliminary FIRM maps.



        S_Gen_Struct
        General structures for non-revised areas were captured from the previous effective
        FIRM and digital orthoquads. Structures for revised areas were provided by the
        modeling consultants.

        S_Label_Ld
        Label leaders for non-revised areas were developed from 2004 effective FIRM and
        adjusted to fit within the map panel. Leaders for revised areas were produced in
        accordance with Appendix K from FEMA’s Guidelines and Specifications for Flood
        Hazard Mapping Partners.

        S_Label_Pt
        Label points for all non-revised and revised areas were automatically created from the
        annotation feature class.

        S_Perm_Bmk
        Permanent benchmarks were downloaded from the National Geodetic Survey website
        at www.ngs.noaa.gov in shapefile format. This information was re-projected to the
        North American Datum 1983 UTM Zone 15N coordinate system.

        S_PLSS_Ar
        U.S. Public Land Survey System information was provided by the Minnesota
        Department of Natural Resources and projected to the North American Datum 1983
        UTM Zone 15N coordinate system.

        S_PLSS_Ln
        The S_PLSS_Ln spatial table was derived from the S_PLSS_Ar spatial table.
        Topology rules were established to ensure that the S_PLSS_Ar and S_PLSS_Ln
        spatial tables were coincident.




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        S_Pol_Ar
        Political areas were provided in a polygon shapefile by the FEMA NSP. Political
        areas were created from Microstation drawings that were used to produce the 2004
        effective FIRM.



        S_Pol_Ln
        Political boundaries were provided in a line shapefile by the FEMA NSP. Topology
        rules were established to ensure that the S_Pol_Ar and S_Pol_Ln spatial tables were
        coincident.

        S_Quad_Index
        The USGS 24K quad index was downloaded from the USGS website and projected to
        the North American Datum 1983 UTM Zone 15N coordinate system.

        S_Trnsport_Ln
        Transportation data was provided by the Minnesota Department of Transportation and
        various communities within Hennepin County. Some of the transportation features
        were adjusted to fit the 2004 effective FIRM and/or digital orthoquads in order to
        match non-revised flood areas. Transportation features were verified at a scale less
        than 1:20,000. Railroad features were captured from the existing countywide FIRM
        at a scale of 1:6000.

        S_Wtr_Ar
        Water feature areas for non-revised areas were developed from a water feature line
        shapefile that was provided by the NSP. The shapefile was created from Microstation
        drawings that were used to produce the 2004 existing FIRM.

        S_Wtr_Ln
        Water feature lines for non-revised areas were provided by the NSP. These lines
        were originally developed from Microstation drawings used to produce the 2004
        effective FIRM. Water lines for revised areas were provided by the modeling
        consultants who developed the revised flood areas. Additional water lines have been
        captured from digital orthophotos.



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        S_XS
        Cross sections for non-revised areas were provided in a line shapefile provided by the
        NSP. Revised cross sections were provided by the modeling consultants. Water
        surface elevations for Nine Mile Creek were calculated and the XP-SWMM model
        node instead of at the cross section. Therefore, cross sections for Nine Mile Creek
        were not included in the DFIRM database.

        The following tables are also included:
        L_COMM_INFO
        L_MT1_LOMC
        L_SOURCE_CIT
        L_STN_START
        L_WTR_NM
        STUDY_INFO

        The following Enhanced Tables will be included in the Final DFIRM database
        S_NODES
        S_SUBBASINS
        L_CASE_INFO
        L_HYDRA_MODEL
        L_HYDRO_MODEL
        L_NODE_DISCH
        L_STORM_CURVE
        L_STORM_INFO
        L_SUBBAS_DISCH
        L_XS_RATINGS

        3.2     QA\QC PROCESS

        Black & Veatch enforced multiple levels of review during the creation of the DFIRM
        database and DFIRM maps. As part of Task 13A, two rounds of visual QC were
        preformed for all non-revised panels. The visual inspection included identifying base
        map/flood hazard feature and panel layout discrepancies. Printed FIRM panel index
        maps were used in order to monitor the progress of the QA/QC and map revisions.
        Under Task 14B, Black & Veatch preformed three more rounds of visual QC

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        including an engineer review. Prior to the completion of Task 14B, Black & Veatch
        submitted sample FIRM maps to FEMA RMC 5 for review. Comments and
        suggestions made by the RMC were incorporated into the preliminary DFIRM
        database and maps.

        The following is a compiled list of specifications that were enforced during the
        QA/QC for Hennepin County. These criteria specifically apply to map graphics,
        annotation, and database QC. This list was developed from FEMA’s Guidelines and
        Specifications for Flood Hazard Mapping Partners: Appendix K: (April 2003) as well
        as input from Black & Veatch, the FEMA NSP, and the RMC for FEMA Region 5
        and 7.

        3.2.1   ANNOTATION and SYMBOLOGY

        A. General

        1. Annotation must be placed on top of a linear feature if a leader is not used. This
           includes Roads, Streams, BFEs, Political Boundaries, and General Structures.

        2. All stacked labels should be center justified.

        3. All annotation must be oriented in the same direction.
           Example: Transportation labels should read from Bottom to Top, and Left to
           Right.

        4. If a feature is labeled twice, both labels should not be placed in close proximity to
           each other.

        5. Align all text of a linear feature to follow the angle of the line unless it is
           leadered.

        6. Arrows should always be snapped to a line feature.

        7. Dot leaders should always be inside a polygon feature.

        8. Leaders must always point from label to feature.

        B. Base Map Features

        1. Street labels that are parallel should line-up whenever possible.

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            Example: Street labels should be parallel evenly distributed in urban areas.

        2. Water features that are 75% covered by a flood zone must be labeled. This
           includes:
           a. Unnamed linear water features should be labeled as “Unnamed Creek” (10pt
               Times New Roman, Bold, Italic.). Example: “Unnamed Creek”
           b. Unnamed lakes and ponds should be labeled “Lake” or “Pond”
               (8pt Times New Roman, Bold, Italic.) Example: “Lake”

        3. A double line stream should not have a stream centerline unless the centerline is a
           profile base line.

        4. Non-leadered streams must be inside the SFHA. Stream labels outside a SFHA
           must be leadered.

        5. All general structure features must be labeled
           a. Culverts, Flume, Penstock, Aqueduct : 8pt Arial Italics CLC
           b. Levee, Dike : 8pt Arial Italics CLC
           c. Dam, Weir: 8pt Arial CLC or CAPS
           d. Pier, Dock, Jetty, Sea Wall: 8pt Arial Italics CLC

        6. Interstates should not have an “I” in the label, i.e. “I-35”

        7. For the S_PLSS_Ln table, the following precedence should apply: TOWNSHIP,
           RANGE, SECTION, QUARTER SECTION, and MEANDER.

        8. County boundary lines should not have other feature lines under them. For
           example: If a PLSS line falls on the county boundary, only the county boundary
           should be visible.

        9. Every community on a map must include a Community Area Label with
           community name and CID number. 8 – 24 Pt. Times New Roman Bold CLC.

        10. Each map should include a community boundary label unless space is limited. 10
            Pt. Arial CAPS

        11. All railroad features must be labeled as “RAILROAD”. 8pt Arial Italics Caps.

        12. Remove duplicate Community labels and place in center of map, within the
            community boundary whenever possible.

        C. Flood Hazard Features

        1. Zone X shaded and Zone X un-shaded should not be referenced using one label.

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        2. Check for “Limit of Detailed Study” Vs. “Limit of Study”. “Limit of Detailed
           Study” represents the terminus of a detailed study along the main branch. “Limit
           of Study” represents the downstream boundary of an approximate zone that
           terminates at a detailed study.

        3. “Limit of Detailed Study” and “Limit of Study” must be symbolized by a white
           line unless SFHA terminates.

        4. A Static BFE label must be placed if a BFE line is absent from a detailed studied
           flood zone.

        5. For the S_Fld_Haz_Ln table, the following precedence should be applied: LIMIT
           OF DETAILED STUDY, LIMIT OF STUDY, LIMIT OF FLOODWAY,
           FLOODWAY, 1 PCT ANNUAL CHANCE FLOOD HAZARD, ZONE BREAK,
           0.2 PERCENT ANNUAL CHANCE FLOOD HAZARD, FLOWAGE
           EASEMENT BOUNDARY, and STATE ENCROACHMENT LINE.

        6. Add “FLOODING EFFECTS____” note where detailed source can not be shown
           on the firm (i.e. Zone AE at the corner of a FIRM panel).

        7. XS letters must fall completely within the hexagon.

        8. Zone Breaks that are between flood zones must be white. Zone breaks at the
           terminus of a flood zone must be black.

        D. Coordinate graphics

        1. All section numbers should be centered and aligned whenever possible.

        2. Township and Range labels should be placed near the edge of a FIRM panel, at
           each side of the map, along the Township and/or Range line, and inside the data
           frame.

        3. Add Township/Range Note for each panel if necessary. If a panel has both
           Township AND Range labels, it does not need the Note. However, if it only has a
           Township OR only a Range, OR neither, the Note is required.

        4. Annotation should not overlap UTM tic marks.

        3.2.2   LEGEND

        1. Legend symbols must match map symbology: Refer to Appendix K.
              a. 1% annual chance

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                b. floodway
                c. zone x
                d. special flood hazard area (zone breaks)
                e. BFE thickness
                f. cross section
                g. UTM should read Zone 15
                h. State Plane should read Minnesota State Plane and FIPZONE 2203

        2. Make sure that geographic coordinates are referenced to the correct projection and
            datum.

        3. A revision note is required for all revised map panels.

        3.2.3   TITLE BLOCK

        1. Community and number label on map matches Community and number on Title
           Block. Confirm that if it is in the panel, it is included in the title block.

        2. Total number of panels in Title Block should be consistent for each panel.

        3.2.4   DATA FRAME

        1. Check for consistent interval for UTM and State Plane tic labels.
           a. UTM – interval at every 1,000 meters
           b. State Plane – interval at every 5,000 feet

        2. Make sure the “Joins Panel” label is referencing the correct panel.

        3. Make sure all “Joins Panel” labels are lined up consistently and closely match
           following coordinates: Top - 24.35651, Bottom- 1.278257, Left - 9.853843, Right
           - 26.34132

        4. Make sure tic marks are all moved up to panel boundary and centered along the
           frame.

        5. Make sure data frame border is not shifted.

        3.2.5   NOTES TO USERS

        1. Notes to Users frame must be 15.15 inches in height.

        2. Base Map information note must be included.

        3. Profile base line note must be included.

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        3.2.6   DFIRM DATABASE CHECKLIST

        1. Cross Section/BFE location and information should be checked against the
           floodway data tables and stream profiles in the FIS report.

        2. Ensure that all required Spatial and Lookup tables are included for Standard and
           Enhanced tables.

        3. Primary and Foreign keys should match between spatial and look-up tables.

        4. All required fields must be properly formatted and attributed.

        5. Each record must represent one feature.

        6. Ensure that there are no Multipart features.

        7. BFE’s and Cross Sections must not cross each other.

        8. Flood/road relationship must always be maintained.

        9. Stream feature must stay within flood zone boundaries.

        10. Ensure that topology has been validated and errors are corrected.




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