PLATTE COUNTY, MISSOURI AND INCORPORATED AREAS VOLUME 1 OF 2

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1 PLATTE COUNTY, MISSOURI VOLUME 1 OF 2 COMMUNITY NAME COMMUNITY NUMBER CAMDEN POINT, CITY OF DEARBORN, CITY OF EDGERTON, CITY OF FARLEY, VILLAGE OF FERRELVIEW, VILLAGE OF HOUSTON LAKE, CITY OF IATAN, VILLAGE OF LAKE WAUKOMIS, CITY OF NORTHMOOR, CITY OF PARKVILLE, CITY OF PLATTE CITY, CITY OF PLATTE COUNTY (UNINCORPORATED S) *PLATTE WOODS, CITY OF RIDGELY, VILLAGE OF RIVERSIDE, CITY OF TRACY, CITY OF WEATHERBY LAKE, CITY OF WESTON, CITY OF *No Special Flood Hazard Areas Identified Platte County Effective Date: April 2, 2015 Federal Emergency Management Agency FLOOD INSURANCE STUDY NUMBER 29165CV001A

2 NOTICE TO FLOOD INSURANCE STUDY USERS Communities participating in the National Flood Insurance Program have established repositories of flood hazard data for floodplain management and flood insurance purposes. This Flood Insurance Study may not contain all data available within the repository. It is advisable to contact the community repository for any additional data. Selected Flood Insurance Rate Map panels for the community contain information that was previously shown separately on the corresponding Flood Boundary and Floodway Map panels (e.g., floodways, cross sections). In addition, former flood hazard zone designations have been changed as follows: Old Zone A1 through A30 V1 through V30 B C New Zone AE VE X X Part or all of this Flood Insurance Study may be revised and republished at any time. In addition, part of this Flood Insurance Study may be revised by the Letter of Map Revision process, which does not involve republication or redistribution of the Flood Insurance Study. It is, therefore, the responsibility of the user to consult with community officials and to check the community repository to obtain the most current Flood Insurance Study components. Initial Countywide FIS Effective Date: April 2, 2015 i

3 TABLE OF CONTENTS VOLUME INTRODUCTION Purpose of Study Authority and Acknowledgments Pre-Countywide Study Countywide Study Coordination Pre-Countywide Study Countywide Study...5 Page 2.0 STUDIED Scope of Study Pre-Countywide Study Countywide Study Community Description Principal Flood Problems Flood Protection Measures ENGINEERING METHODS Hydrologic Analyses Upper Mississippi River System Flow Frequency Study Methodology Hydraulic Analyses Upper Mississippi River System Flow Frequency Study Methodology Vertical Datum Methods for the Missouri River FLOODPLAIN MANAGEMENT APPLICATIONS Floodplain Boundaries Methods for the Missouri River Floodways Methods for the Missouri River INSURANCE APPLICATION FLOOD INSURANCE RATE MAP OTHER STUDIES LOCATION OF DATA ii

4 TABLE OF CONTENTS (continued) VOLUME 1 Page 9.0 BIBLIOGRAPHY AND REFERENCES FIGURES Figure 1 Floodway Schematic TABLES Table 1 Summary of Discharges Table 2 Manning s n Values Table 3 Floodway Data Table 4 Community Map History iii

5 TABLE OF CONTENTS VOLUME 2 Exhibit 1 Flood Profiles Bear Creek Bee Creek Bee Creek Tributary Benner Branch Brills Creek Brush Creek Brush Creek Tributary 1 Burlington Creek Burlington Creek Tributary 1 Burlington Creek Tributary 2 East Creek East Fork Line Creek First Creek First Creek Tributary 1 Grove Creek Jumping Branch Line Creek Line Creek Tributary 1 Line Creek Tributary 2 Missouri River Old Maids Creek Platte River Rush Creek Second Creek Second Creek West Branch Todd Creek Tributary to Todd Creek Walnut Creek Wells Branch White Branch Wildcat Branch Panels 01P-02P Panels 03P-05P Panels 06P-07P Panels 08P-09P Panel 10P Panels 11P-14P Panel 15P Panels 16P-19P Panel 20P Panel 21P Panel 22P Panel 23P Panels 24P-26P Panel Panel 28P Panels 29P-30P Panels 31P-34P Panels 35P-36P Panels 37P-38P Panels 39P-42P Panel 43P Panels 44P-45P Panels 46P-47P Panels 48P-53P Panel 54P Panels 55P-57P Panels 58P Panels 59P-61P Panels 62P-63P Panels 64P-66P Panels 67P-68P PUBLISHED SEPARATELY: Flood Insurance Rate Map Index Flood Insurance Rate Map iv

6 1.0 INTRODUCTION 1.1 Purpose of Study FLOOD INSURANCE STUDY PLATTE COUNTY, MISSOURI This Flood Insurance Study (FIS) report revises and updates information on the existence and severity of flood hazards in the geographic area of Platte County, Missouri, including: the Cities of Camden Point, Dearborn, Edgerton, Houston Lake, Lake Waukomis, Northmoor, Parkville, Platte City, Platte Woods, Riverside, Tracy, Weatherby, Lake and Weston; the Villages of Farley, Fe rre l vi ew, Iatan, and Ridgely; and the unincorporated areas of Platte County, and aids in the administration of the National Flood Insurance Act of 1968 and the Flood Disaster Protection Act of This study has developed flood-risk data for various areas of the community that will be used to establish actuarial flood insurance rates and to assist the community in its efforts to promote sound floodplain management. Minimum floodplain management requirements for participation in the National Flood Insurance Program (NFIP) are set forth in the Code of Federal Regulations at 44 CPR, This FIS revises and supersedes previous FISs countywide. This information will be used by the communities to update existing floodplain regulations as part of the regular phase of the NFIP. The information will also be used by local and regional planners to further promote sound land use and floodplain development. As part of this revision, the format of the map panels has changed. Previously, flood-hazard information was shown on both the Flood Insurance Rate Map (FIRM) and Flood Boundary and Floodway Map (FBFM). In the new format, all base flood elevations, cross sections, zone designations, and floodplain and floodway boundary delineations are shown on the FIRM and the FBFM has been eliminated. Some of the flood insurance zone designations were changed to reflect the new format. Areas previously shown as numbered Zone A were changed to Zone AE. Areas previously shown as Zone B were changed to Zone X (shaded). Areas previously shown as Zone C were changed to Zone X (unshaded). In addition, all Flood Insurance Zone Data Tables were removed from the FIS report and all zone designations and reach determinations were removed from the profile panels. The Digital Flood Insurance Rate Map (DFIRM) and FIS Report for this countywide study have been produced in digital format. Flood hazard information was converted to meet FEMA DFIRM database specifications and Geographic Information System (GIS) format requirements. The flood hazard information was created and is provided in a digital format so that it can be incorporated into a local GIS and be accessed more easily by the community. Please note that the City of Platte Woods has no special flood hazard areas identified, and the City of Dearborn is geographically located in Platte and Buchanan Counties. Please note that the City of Kansas City is geographically located in Cass, Clay, Platte and Jackson County, Missouri. T h e C i t y o f S m i t h v i l l e i s g e o g r a p h i c a l l y l o c a t e d i n P l a t t e a n d C l a y C o u n t y, M i s s o u r i. All flood hazard information for the Cities of Kansas City and Smithville is not included in this county FIS and FIRM. For flood insurance and all regulatory purposes, refer to separately printed Jackson County, Missouri and Incorporated Areas for Kansas City FIS and FIRM. For the City of Smithville refer to the Clay County, Missouri and Incorporated Areas FIS and FIRM. In some states or communities, floodplain management criteria or regulations may exist that are more restrictive or comprehensive than the minimum Federal requirements. In such cases, the more restrictive criteria take precedence and the State (or other jurisdictional agency) will be able to explain them. 1

7 1.2 Authority and Acknowledgments Pre-Countywide Study City of Dearborn: The hydrologic and hydraulic analyses for this study were performed by the U. S. Army Corps of Engineers (USACE), Kansas City District, for the Federal Insurance Administration (FIA), under Inter-Agency Agreement No. H-10-77, Project Order No.8. This work, which was completed in November 1977, covered all significant flooding sources affecting the City of Dearborn (Reference 8). City of Edgerton: The hydrologic and hydraulic analyses for this study were performed by the USACE, Kansas City District, for the FIA, under Inter-Agency Agreement No. H-10-77, Project Order No.8. This work, which was completed in May 1977, covered all significant flooding sources affecting the City of Edgerton (Reference 9). City of Northmoor: The hydrologic and hydraulic analyses for the November 1977 FIS were performed by the USACE, Kansas City District, for FEMA, under Interagency Agreement No. IAA-H The work was completed in May The hydraulic analysis for this revision to the Line Creek portion of the FIS was prepared for the USACE, Kansas City District, by Half Associates, Inc. The analysis was completed in September 1999 (Reference 14). City of Parkville: The hydrologic and hydraulic analyses for this study were performed by the USACE, Kansas City District, for the FIA, under Inter-Agency Agreement No. IAA-H-7-76, project Order No. 13. This work, which was completed in June 1977, covered all significant flooding sources affecting the City of Parkville, Missouri (Reference 12). Platte County: Unincorporated Areas The hydrologic and hydraulic analyses for this study were performed by the USACE, Kansas City District, for the FIA, under Inter-Agency Agreement No. H-10-77, Project Order No. 8. This work, which was completed in November 1977, covered all significant flooding sources affecting the unincorporated areas of Platte County (Reference 17). City of Riverside: The source of authority for this Flood Insurance Study is the National Flood Insurance Act of 1968, as amended. The hydrologic and hydraulic analyses for this study were performed by the USACE, Kansas City District, for the FIA, under Inter-Agency Agreement No. IAA- H-16-75, Project Order No. 13. This work, which was completed in December 1975, covered all flooding sources affecting the City of Riverside (Reference 11). City of Tracy: The hydrologic and hydraulic analyses for this study were performed by the USACE, Kansas City District, for the FIA, under Inter-Agency Agreement No. H-I0-77, Project Order No.8. This work, which was completed in September 1977, covered all significant flooding sources affecting the City of Tracy (Reference 13). City of Weston: The hydrologic and hydraulic analyses for this study were performed by the USACE, Kansas City District, for the FIA, under Inter-Agency Agreement No. H-10-77, Project Order No.8. This work, which was completed in September 1977, covered all significant flooding sources affecting the City of Weston (Reference 15) Countywide Study The sources of authority for this FIS report are the National Flood Insurance Act of 1968 and 2

8 the Flood Disaster Protection Act of For this countywide FIS report, AMEC Earth and Environmental, Inc., performed the hydrologic and hydraulic analyses for Platte County and Incorporated Areas as contracted by the State of Missouri Emergency Management Agency (SEMA) under Cooperative Agreement No. EMK CA This analysis was completed on April 30, The hydrologic and hydraulic analyses for the Missouri River were performed by the USACE as part of the Upper Mississippi River System Flow Frequency Study (UMRSFFS). This study was a collaboration of effort between the Rock Island, St. Louis, Kansas City, Omaha, and St. Paul districts and was completed in The 1-percent-annual-chance flood water surface profile and floodway computations on the Missouri River were performed within HEC-RAS for FEMA under Interagency Agreement No. HSFE07-06-X-0012 by the Kansas City and Omaha districts and were completed in The floodplain mapping for the Missouri River was performed by Watershed Concepts for FEMA under Contract No. HSFE07-07-C Planimetric base map information shown on all FIRM panels was derived from the National Agriculture Imagery Program (NAIP) 2006, 2 meter orthoimagery. These base map files were provided in digital format by Missouri Spatial Data Information service (MSDIS). Additional information was derived from the U.S. Geological Survey (USGS). Users of this FIRM should be aware that minor adjustments may have been made to specific base map features (Reference 18). The coordinate system used for the production of this FIRM is the North American Datum of 1983 (NAD 83), State Plane Missouri West, FIPS 2403, feet. Corner coordinates shown on the FIRM are in latitude and longitude referenced to the Universal Transverse Mercator (UTM projection, NAD 83 Zone 15N). 1.3 Coordination Pre-Countywide Study City of Dearborn: Basic data research was coordinated through and centered with officials of the City of Dearborn. The Missouri Department of Natural Resources, the Water Resources Division of the U. S. Geological Survey (USGS), the U. S. Department of Agriculture, Soil Conservation Service (SCS), and local residents of the area were contacted and supplied basic flood information. The Mid-American Regional Council was contacted to obtain aerial photography for updating of map features and descriptive historical Information. Coordination for the Dearborn study included meeting with city officials on September 24, 1976, for the purpose of data collection and on October 17, 1977 to discuss floodway criteria. On June 27, 1978, the results of the study were reviewed and accepted at a final coordination meeting attended by city officials, representatives of the FIA, and the USACE, Kansas City District (Reference 8). City of Edgerton: Basic data research was coordinated through and centered with the Edgerton city officials. The Missouri Department of Natural Resources, the Water Resources Division of the U.S. Geological Survey (USGS), the U.S. Department of Agriculture, Soil Conservation Service (SCS), and local residents of the area were contacted and supplied basic flood information. The Mid-America Regional Council was contacted to obtain aerial photography for updating of map features and descriptive historical information. Coordination for the City of Edgerton study included meetings with city officials on September 24, 1976, for the purpose of data collection and on November 22, 1977 to discuss floodway criteria. On August 23, 1978, the results of the work by the Kansas City USACE were reviewed and accepted at a final coordination meeting attended by personnel of the Kansas City USACE, the FIA, and officials of, the City of Edgerton (Reference 9). 3

9 City of North Kansas City: The North Kansas City study was coordinated with the City of North Kansas City. The City Engineer's office assisted the study by providing base maps of the corporate area to the USACE (Reference 16). City of Northmoor: The results of the 1976 analyses were reviewed at the final CCO meeting held on March 23, 1976, and attended by representatives of the City of Northmoor. All problems raised at that meeting were addressed in the November 1977 FIS. The Missouri State Emergency Management Agency submitted the revised analysis to FEMA on October 5, 2000 and requested that the FIS for the City of Northmoor be revised. With the request was a concurrence from the city for the revision. On October 10, 2001, FEMA sent the city a letter informing them that FEMA would revise the City of Northmoor study (Reference 14). City of Parkville: Basic data research was coordinated through and centered with the Parkville city officials. Residents of the area were contacted and supplied basic flood information. The Missouri Department of Natural Resources, the Water Resources Division of the U.S. Geological Survey, and the U.S. Soil Conservation Service were contacted for any available information. On March 16, 1976, further coordination meetings were held among city officials, the FIA, and representatives of the USACE for the purpose of data collection. On January 5, 1977, floodway criteria were discussed among the same officials. On June 10, 1977, a final coordination meeting to review the draft of this report was held, with the same persons attending. The Mid-America Regional Council was contacted to obtain aerial photography for updating of map features and descriptive historical information (Reference 12). City of Riverside: Basic data research was coordinated through and centered with the Riverside city officials. Residents of the area were contacted to obtain basic flood information. Coordination for the Riverside study included meetings with city officials on September 17, 1975, and September 18, 1975, for the purpose of data collection. On November 18, 1975, a meeting was held to discuss floodway criteria. A final coordination meeting to review the draft of this report was held with city officials on March 23, The Mid-America Regional Council was contacted to obtain aerial photography for updating of map features and descriptive historical information (Reference 11). City of Tracy: Basic data research was coordinated through and centered with the City of Tracy officials. The Missouri Department of Natural Resources, the Water Resources Division of the U.S. Geological Survey (USGS), the U.S. Department of Agriculture Soil Conservation Service, and local residents of the area were contacted and supplied basic flood information. The Mid America Regional Council was contacted to obtain aerial photography for updating of map features and descriptive historical information. Coordination for the City of Tracy study included meetings with city officials on September 24, 1976, for the purpose of data collection and on October 13, 1977, to discuss floodway criteria. On June 29, 1978, the results of the study were reviewed and accepted at a final coordination meeting attended by the above-mentioned agencies (Reference 13). City of Weston: Basic data research was coordinated through and centered with the City of Weston, city officials. The Missouri Department of Natural Resources, the Water Resources Division of the U.S. Geological Survey (USGS)~ the U.S. Department of Agriculture, Soil Conservation Service (SCS), and local residents of the area were contacted and supplied basic flood information. The Mid-America Regional Council was contacted to obtain aerial photography for updating of map features and descriptive historical information. Coordination for the City of Weston study included meetings with city officials on September 24, 1976, for the purpose of data collection and on November 16, 1977, to discuss floodway criteria. On June 26, 1978, the results of this study were reviewed and accepted at a final coordination meeting attended by city officials, representatives of the Missouri Department of Natural Resources, and the USACE, Kansas City District (Reference 15). 4

10 1.3.2 Countywide Study The initial Consultation Coordination Officer (CCO) meeting was held in Platte City, Missouri on January 11, 2007, and attended by representatives of FEMA, SEMA, AMEC Earth and Environmental, and Platte County. The results of the study were reviewed at the final CCO meeting held on November 8, 2010, and attended by representatives of FEMA, SEMA, AMEC Earth and Environmental, Platte County, City of Parkville, City of Platte City, City of Riverside, City of Tracy, City of Weatherby Lake, Village of Farley, and Village of Ferrelview. All related issues raised at that meeting have been addressed in this study. 2.0 STUDIED 2.1 Scope of Study Pre-Countywide Study City of Dearborn: The City of Dearborn FIS covered the incorporated area of the City of Dearborn. The areas studied by detailed methods were selected with priority given to all known flood hazard areas, areas of projected development, and proposed construction until September The scope and methods of the study were proposed to and agreed upon by the FIA and the community. A detailed study was made for the entire length of Bee Creek and Bee Creek Tributary within the corporate limits. City of Edgerton: The City of Edgerton FIS covered the incorporated areas of the City of Edgerton. The areas studied by detailed methods were selected with priority given to all known flood hazard areas, areas of projected development, and proposed construction until September The scope and methods of the study were proposed to and agreed upon by the FIA and the community. A detailed study was made for the entire length of Grove Creek within the corporate limits. The areas studied were selected with priority given to all know flood hazard areas and areas of projected development or proposed construction through January The scope and methods of study were proposed to and agreed upon by FEMA and the City of Kansas City. City of Northmoor: The City of Northmoor FIS covered the incorporated areas of the City of Northmoor, Platte County, Missouri. For the November 1977 FIS report, a detailed study was made of the entire length of Line Creek through the corporate area of the City of Northmoor. Limits of the study extended from the southern city limit at U.S. Highway 69 to an area just south of ht Interstate Highway 29 Bridge over Line Creek. A very small portion of East Creek, which flows through the community, was also studied in detail in conjunction with the adjacent community of Riverside. For this study, an updated, detailed hydraulic analysis was performed on Line Creek through the City of Northmoor. The purpose of this study was to update the Line Creek hydraulic computer model in order to quantify the effects of the fill placed within the floodplain. 5

11 City of Parkville: The City of Parkville FIS covered the incorporated area of the City of Parkville, located in southern Platte County, Missouri. A detailed study was made for the entire length of the Missouri River along the corporate boundary of Parkville. One Missouri River tributary, White Aloe Branch, was also studied in detail from its mouth at the Missouri River to the outlet below Riss Lake. Those areas studied by detailed methods were chosen with consideration given to all proposed construction and forecasted development through Platte County Unincorporated Areas: The Platte County Unincorporated Areas FIS covered the unincorporated areas of Platte County, Missouri. The areas studied by detailed methods were selected with priority given to all known flood hazard areas, areas of projected development, and proposed construction until September The scope and methods of the study were proposed to and agreed upon by the FIA and the community. The Missouri River, within the county limits; Walnut Creek from 3,200 feet downstream of Walnut Creek Road to 7,200 feet upstream of Walnut Creek Road; and Burlington Creek, within the Platte County limits, were studied in detail. City of Riverside: The City of Riverside FIS covered the incorporated area of the City of Riverside, located in southeast Platte County, Missouri. Riverside is bordered by the Missouri River on its southern and western boundaries and by the cities of Kansas City and Northmoor on its northern and eastern boundaries. A detailed study was made for the entire length of the Missouri River along the corporate boundary of Riverside. Two Missouri River tributaries affecting the City of Riverside, Burlington Creek and Line Creek, were also studied in detail. Burlington Creek was studied from just upstream of Highway 9 to the confluence with the Missouri River. Line Creek was studied from Riverside s common boundary with Kansas City and Northmoor to its confluence with the Missouri River. Two tributaries of East Creek, Jumping Branch and Line Creek, were also studied in detail. Jumping Branch was studied from Riverside s north boundary to its confluence with Line Creek. A very small portion of East Creek which flows through the community was also studied in detail in conjunction with the Northmoor and Kansas City studies. The areas studied in detail were chosen with consideration given to all forecasted development and proposed construction for the next five years (through 1981). City of Tracy: The City of Tracy FIS covered the incorporated area of the City of Tracy. The areas studied by detailed methods were selected with priority given to all known flood hazard areas, areas of projected development and proposed construction until September The scope and methods of the study were proposed to and agreed upon by the FIA and the community. A detailed study was made for the entire length of the Platte River affecting flooding in the community. The study limits extend from 500 feet downstream of Missouri Highway 92 to 1,300 feet downstream of Route 29. City of Weston: This FIS covered the incorporated area of the City of Weston. 6

12 The areas studied by detailed methods were selected with priority given to all known flood hazard areas, areas of projected development and proposed construction until September The scope and methods of the study were proposed to and agreed upon by the FIA and the community. A detailed study was made for the entire length of Wells Branch, Brills Creek, Benner Branch, and the Missouri River. Bear Creek was not studied since the Missouri River would control all floods Countywide Study This current FIS report covers the geographic area of Platte County, Missouri, including the incorporated communities listed in Section 1.1. The areas studied by detailed methods were selected with priority given to all known flood hazards and areas of projected development or proposed construction. The flooding sources studied by new detailed hydrologic and hydraulic analyses are listed below. 1. Bear Creek from confluence with Missouri River to approximately 5.0 miles above confluence with Missouri River. 2. Bee Creek from approximately 20 miles to 23 miles above confluence with Missouri River. 3. Bee Creek Tributary from confluence with Bee Creek to approximately 1.0 mile above confluence with Bee Creek. 4. Benner Branch from confluence with Bear Creek to approximately 0.8 miles above confluence with Brills Creek. 5. Brills Creek from confluence with Benner Branch to approximately 1.2 miles above confluence with Benner Branch. 6. Brush Creek from approximately 5 miles to 13 miles above confluence with Missouri River. 7. Brush Creek Tributary 1 from confluence with Brush Creek to approximately 1.1 miles above confluence with Brush Creek. 8. Burlington Creek from confluence with Missouri River to approximately 4.3 miles above confluence with Missouri River. 9. Burlington Creek Tributary 1 from confluence with Burlington Creek to approximately 0.3 miles upstream of Burlington Creek. 10. Burlington Creek Tributary 2 from confluence with Burlington Creek to approximately 0.3 miles upstream of Burlington Creek. 11. East Creek from confluence with Line Creek to approximately 0.7 miles above confluence with Line Creek. 12. East Fork Line Creek from confluence with Line Creek to approximately 1.4 miles above confluence with Line Creek. 13. First Creek from county boundary to county boundary. 7

13 14. First Creek Tributary 1 from confluence with First Creek to county boundary. 15. Grove Creek from approximately 2.2 miles to 4 miles from confluence with Platte River. 16. Jumping Branch from confluence with East Creek to approximately 1.3 miles above confluence with East Creek. 17. Line Creek from confluence with Missouri River to approximately 8.3 miles above confluence with Missouri River. 18. Line Creek Tributary 1 from confluence with Line Creek to approximately 1.5 miles above confluence with Line Creek. 19. Line Creek Tributary 2 from confluence with Line Creek to approximately 1.3 miles above confluence with Line Creek. 20. Old Maids Creek from confluence with Line Creek to county boundary. 21. Platte River from confluence with Missouri River to approximately 16.8 miles above confluence with Missouri River. 22. Rush Creek from confluence with Missouri River to approximately 4.0 miles above confluence with Missouri River. 23. Second Creek from county boundary to approximately 14.0 miles upstream of county boundary. 24. Second Creek West Branch from confluence with Second Creek to approximately 2.2 miles above confluence with Second Creek. 25. Todd Creek from Kansas City Corporate Limits to approximately 6.7 miles upstream of Kansas City Corporate Limits. 26. Tributary to Todd Creek from confluence with Todd Creek to approximately 1.6 miles above confluence with Todd Creek. 27. Walnut Creek from confluence with Rush Creek to approximately 5.7 miles above confluence with Rush Creek. 28. Wells Branch from confluence with Bear Creek to approximately 1.4 miles above confluence with Bear Creek. 29. White Branch from confluence with Rush Creek to approximately 1.1 miles above confluence with Rush Creek. 30. Wildcat Branch from confluence with Todd Creek to approximately 3.6 miles above confluence with Todd Creek. The areas studied by approximate methods were selected with priority given to all known flood hazards and areas of projected development or proposed construction through December Approximate analyses were used to study those areas having a low development potential or minimal flood hazards. Included in these analyses were Alger Creek, Bear Creek, Bee Creek, Bell Creek, Benner Branch, Bleazard Branch, Bonnell Branch, Brills Creek, Brush Creek, Chestnut Branch, Clear Branch, Dicks Creek, First Creek, Fox Creek, Gibson Branch, Grove Creek, Hardesty Branch, Holland Branch, Jordan Branch, Jowler Creek, Jumping Branch, Little Jordan Branch, Little Platte River, Mission Creek, Muddy Branch, Naylor Creek, Owl Creek, Pedee Creek, Platte River, Prairie Creek, Rush Creek, Sand Branch, Second Creek, 8

14 Shanks Branch, Short Creek, South Sugar Creek, Sugar Creek, Todd Creek, Wells Branch, White Branch and associated tributaries. The scope and methods of study were proposed, and agreed upon, by FEMA, Representatives of Platte County and the State of Missouri. The scope and methods of study were proposed to, and agreed upon, by representatives of Platte County, AMEC Earth & Environmental Inc., and the Missouri State Emergency Management Agency (SEMA). 2.2 Community Description Platte County: Platte County is located in west-central Missouri and lies northwest of Kansas City, Missouri. Platte County contains part of the Kansas City incorporated area. It is bounded by Buchanan County, Missouri, on the north, Clinton County and Clay County, Missouri, on the east, and Wyandotte, Leavenworth, and Atchison Counties, Kansas, on the south and west. Platte County was first recognized in 1837 as a county. The county is primarily unincorporated with a population of 84,574. (Reference 5) The incorporated cities in the county are Camden Point, Dearborn, Edgerton, Farley, Ferrelview, Houston Lake, Iatan, Kansas City, Lake Waukomis, Northmoor, Parkville, Platte City, Platte Wooes, Ridgely, Riverside, Tracy, Weatherby Lake, and Weston. The average summer temperature is 86.4 degrees Fahrenheit with an extreme high temperature in August 1984 of 109 degrees Fahrenheit. The average winter temperature is 39.6 degrees Fahrenheit with an extreme low temperature of -23 degrees Fahrenheit in December The average annual precipitation in the area is inches, based on records from 1972 to The heaviest rainfall is expected during the spring and summer months. The heaviest precipitation recorded for a 24-hour period was 8.82 inches in September 1977 (Reference 7). Humidity is normally greater than 60 percent due to the abundance of precipitation, the numerous rivers, and the current of warm, moist air from the Gulf of Mexico. The soils of the area are generally fine loams and loess. The topography of the land is very flat in the floodplains; however, there are some bluffs near the Platte County line in the north and east (Reference 17). City of Dearborn: Dearborn is a small town of 529 people, located in north Platte County, Missouri, approximately 30 miles north of Kansas City. (Reference 5) Dearborn is bordered by the unincorporated areas of Platte County. The vegetation in the floodplain consists mainly of trees and shrubs with most of the watershed consisting of either pasture or cropland. The area around Dearborn has been glaciated. The soil found in the area is loess, which is a medium textured soil with a moderate infiltration rate. The topography of the land is flat, rising slowly from the floodplain. Most of the city is located on higher ground out of the floodplain. The development of the floodplain consists primarily of small businesses with a few houses. The city is primarily residential with some commercial development in the western part of the city near the railroad (Reference 8). City of Edgerton: Edgerton is a small town of 533 people, according to the 2000 census. (Reference 5) It is located in northeast Platte County; 40 miles north of Kansas City, Missouri. Edgerton is bordered on all sides by unincorporated Platte County. The soils of the area are generally glaciated loess with moderate permeability. Grove Creek runs through the center of Edgerton toward the southwest corner of the city. The land rises moderately from the broad alluvial floodplain of the Missouri River with most of the city located on higher ground. The development of the floodplain is residential (Reference 9). City of Northmoor: The City of Northmoor is a small, residential community situated in the southeastern corner of Platte County. On May 28, 1951, during a period when annexations were being made, the City of Northmoor was incorporated as a village. On June 22, 1954, the City of Northmoor was incorporated a second time as a fourth class city. The population in 2000, according to the U.S. Bureau of Census, was 399 (Reference 5). The City of Northmoor is bounded on its northern and eastern sides by the City of Kansas City and on its southern and western sides by the City of Riverside. The community is considered to be fully developed, with change in floodplain usage occurring through redevelopment. The topography consists of low, open 9

15 hills. Its creeks and valleys abound with many trees and shrubs that are native to the area. The City of Northmoor is situated in the Line Creek Basin. The creek influences the western part of the town and forms its western boundary. Floodplain development includes mobile homes and single-family housing. Line Creek has numerous tributaries radiating into surrounding communities. The total watershed area of Line Creek is more than 20 square miles and includes residential, commercial, and light industrial development (Reference 14). City of Parkville: Parkville is a small city, with a 2000 population of 4,059 people, located along the Missouri River. (Reference 5) The downstream area is located on flat lowland. Park College, located just east of the downtown area, is on very high ground. A large private lake, Riss Lake, is located in the northern end of the city. Parkville is bordered by the Missouri River on the south Riverside and Kansas City on the east, Kansas City on the north, and Platte County on the west (Reference 12). City of Riverside: Riverside's proximity to the Missouri River and Kansas City area, with access to interstate and railway traffic, has influenced growth in industrial, commercial, and residential development in the last decade. The population in 2000, according to the Bureau of Census, was 2,979. (Reference 5) Riverside's geographic advantages, if developed properly, could result in substantial population gains. History of the area reflects that the people were of German ancestry. In 1924, the area was called Brenner Ridge, a name devised from the original white settlers, the Brenner family, who arrived from Germany in For many years, the area had no stores and trading was done in Harlem or Parkville. The city was incorporated on June 21, Topography in Riverside is diversified. Generally, the southern half is extremely flat and can be described as an alluvial plain, or floodplain, through which the Missouri River has meandered since the end of the last glacial age. Chains of bluffs on both sides of the river mark the limits of the floodplain. The northern half is characterized by attractive low, open hills and valleys. The southern half of the city is primarily cropland where corn, wheat, and alfalfa are grown. The vegetation in the northern valleys is predominantly trees and shrubs native to the area. Existing development in Riverside ranges from commercial and industrial to residential land use. Generally, land north of the bluffs and west of Jumping Branch Creek is an area of residential growth. According to the Master Plan prepared by the Mid-America Regional Council in 1972, a large rectangular area adjacent to the northwest boundaries of town will probably be annexed in the near future. This area, located around Burlington Creek, is zoned residential and has several new housing projects under construction. The northeastern quadrant of Riverside, east of Jumping Branch, is of older residential development and some areas are zoned commercial. U.S. Highway 69, Interstate 635, and Missouri State Highway 9, are the major transportation routes within the study area. The southern half of the city is located in the Missouri River Basin. Most of the area is zoned for industrial development. Present plans call for the construction of several industries in this area in the near future (Reference 11). City of Tracy: Tracy is a small town of 213 people, located in central Platte County, Missouri. (Reference 5) It is bordered by Platte City on the south and unincorporated Platte County on the north, east, and west. The Platte River runs through the southern part of Tracy. The soils of the area are generally fine loams and loess. The topography of the land is very flat in the floodplain, and then rises slowly. Most of the city is located in the floodplain. The development of the floodplain consists primarily of residential areas with a few small businesses (Reference 13). City of Weston: Weston is a small town of 1,631 people located in western Platte County, Missouri, approximately ten miles northwest of Kansas City. (Reference 5) Weston is bordered by unincorporated Platte County. Weston is known for the McCormick Whiskey Distillery and was once an important Missouri River port before the river changed course. The general vegetation consists of typical shrubs and foliage with no unusual factors affecting runoff. The soil is generally silty loam with alluvial plain surrounding the Missouri River. Weston is located.on the edge of the Missouri River floodplain and from there, the topography ascends steeply. The development of the floodplain consists mostly of small businesses and a few houses. Bear Creek runs southeast through Weston. Wells Branch runs west through the southern portion of the city, Benner Branch runs south through the center of the city, and Brills 10

16 Creek, a tributary of Benner Branch, flows southeast to Benner Branch. The Missouri River flows outside the corporate limits but has quite an effect on the flooding of Weston (Reference 15). 2.3 Principal Flood Problems Platte County: The Missouri River, the Platte River, and the Little Platte River are the principal flood threats. The rivers flood often with considerable damages, most notably in 1844, 1903, 1947, and The floods of 1993 through 1995 represent Missouri s worst repetitive flood events. The ravages of these floods left a legacy of destruction, human suffering and property damage. A number of flood-level records were broke in 1993 and, in the USACE Kansas City district, 6 of 48 federal levees and 810 of 810 non-federal levees were overtopped. Since 1990, Platte County has been involved in 4 Presidential Disaster Declarations involving flood. In 7/1993 Platte County received Individual and Public Assistance for Disaster DR 995 related to flooding, in 5/2003 Platte County received Individual Assistance for Disaster DR 1463 related to flooding, in 6/2004 Platte County received Individual Assistance for Disaster DR 1524 related to flooding, and in 6/2007 Platte County received Individual and Public Assistance for Disaster DR 1708 related to flooding (Reference 6). City of Dearborn: Bee Creek is the principal flood threat to the city as a whole. Complete records have not been kept on flooding but townspeople indicate frequent flooding of lower areas (Reference 8). City of Edgerton: Grove Creek is the principal flood threat to the city as a whole. Complete records have not been kept on flooding but townspeople indicate frequent flooding of lower areas (Reference 9). City of North Kansas City: The North Hillside Drainage Ditch and Rock Creek run through the northern part of the city. These streams and the Missouri River periodically overflow and flood adjacent areas of North Kansas City (Reference 16). City of Northmoor: Line Creek is the principal flood threat to the City of Northmoor. The creek originates five miles north and meanders through numerous residential areas and undeveloped land in the City of Kansas City before entering the City of Northmoor. The creek then flows south before emptying into the Missouri River. Line Creek flooding has occurred from highintensity rainfall experienced during thunderstorm activity. A 24-hour precipitation of 4 to 5 inches is capable of causing flood problems. Accounts of flooding before 1974 are sparse. However, the flood of May 1974 was the most severe, with roads and numerous homes being flooded. The creek was extensively altered just north of U.S. Highway 69 during construction of a shopping center, resulting in two 90-degree bends in the channel. Floodwaters flowed through the channel very fast and, when reaching these bends, became potentially destructive (Reference 14). City of Parkville: The Missouri River remains the principal flood threat to the city as a whole. Many floods occurring since 1900 have inundated the City of Parkville, the most recent in 1973 and the worst in White Aloe Branch, which runs through downtown Parkville, is not a serious flood threat due to Riss Lake to the north. Riss Lake is a l54-acre private fishing lake. It has 18 feet of freeboard, with only 2.05 square miles of drainage area above the lake. High-water marks in the downtown area indicate flooding from the Missouri River of 4 to 5 feet in depth in past years (Reference 12). City of Riverside: The Missouri River remains the principal flood threat to the city, due to high intensity rainfall experienced during thunderstorm activity. Records of past flood events in Riverside, prior to its incorporation in 1951, are sparse because of the city's relatively short population span. Although over half of the city was submerged during the May-July flood of 1951, accounts of damage are sparse because the flooded area was relatively undeveloped, being mostly 11

17 cropland; and, also because reports of areas receiving more severe flooding overshadowed that of Riverside. With industrial development in this area proceeding at a relatively fast pace, a flood of 1951 magnitude or greater could prove devastating. Line Creek is the second most serious flood threat in the city. This creek was extensively altered north of U.S. Highway 69 during the construction of a shopping center, resulting in the two 90 bends in the channel. During the flood of May 1974, floodwaters flowed through the channel very fast, becoming potentially destructive at these bends. When the floodwaters left the channel and flowed onto the floodplain, several homes were washed off their foundations and other homes were severely damaged. Continuous landslides and heavy silting of the channel, together with continued development in the upper reaches of Line Creek, will undoubtedly affect flood frequencies and severity in the future. Reportedly, the western end of the shopping center has settled several inches since its construction. According to local residents, the May 1974 flood was considered the worst flood ever experienced in the area. Several homes adjacent to the creek received as much as 24 inches of water in their basements. Bridges were washed out and several roads were overrun by floodwaters-including State Highway 9, the main arterial for the area. Total damage in Riverside from this event was $2,700,000. Residential damage from the event amounted to $145,000. Business damage recorded was over $2,300,000. Municipal damage amounted to $243,000. Burlington Creek, located along the western edge of the city, is Riverside's third most serious flood threat. From local reports, much of the flooding problem can be attributed to backwater created by inadequate bridging of the channel, rapid silting and accumulation of debris in the channel due to extensive construction within the watersheds, and increased development in the upper reaches of the creek causing greater runoff quantities (Reference 11). City of Tracy: The Platte River is the main flooding source of Tracy. Floods in the Platte River basin have caused extensive damage in the past, but post-flood surveys to evaluate losses have been made only since The floods of 1844 and 1915 have been described as extensive in area and very severe in effect, but reliable data upon which to base a monetary damage appraisal are lacking. Since 1941, field surveys and detailed damage evaluations have been made following the more severe floods. The greatest damage of reliable record occurred during the June 1947 flood, when damages within the basin were evaluated at $7,713,000. Some flooding has occurred on an average of once every two years. The most severe floods occurred in 1844, 1915, 1947, 1951, and 1964 (Reference 13). City of Weston: The Missouri River is the principal flood threat to the city as a whole. Major floods have occurred in 1844, 1903, and Many lesser ones have flooded the low areas (Reference 15). 2.4 Flood Protection Measures Platte County: Many flood protection measures are in place to help Platte County. A number of flood control reservoirs and levees which primarily retain 1-percent-annual-chance flood have been built on the Missouri River, and one reservoir has been built on the Little Platte River. In January 3, 2010 the Waldron (MRLS 400-L) and Farley-Beverly (MRLS 408-L) levee systems qualified for Provisionally Accredited Levees (PAL) designation. To maintain accreditation, the community or levee owner must provide the documentation necessary to comply with 44 CFR Section requirements to FEMA by January 3, Many low frequency private agricultural levees have been built along the Platte River (Reference 17). City of Dearborn: No major flood control measures are planned for Dearborn and none are in existence (Reference 8). City of Edgerton: No major flood control measures are planned for Edgerton and none are in existence (Reference 9). 12

18 City of North Kansas City: A levee located along the Missouri River protects North Kansas City from floods, including the 0.2-percent-annual-chance flood. Only a small, undeveloped portion of the Missouri River floodplain located between the river and levee is vulnerable to flooding. The North Hillside Drainage Ditch is contained on the south side by a levee. The levee will not adequately contain the 1-percent-annual-chance flood and 0.2-percent-annual-chance flood. Waters from these floods will overtop the levee, west of the Midtown Freeway, and inundate the adjacent depressed area. A Midtown Freeway exit ramp will impound these waters. There is a culvert for the North Hillside Drainage Ditch under the Freeway. The discharge capacity of this culvert is such that the 100-year flood is contained by the levee east of the Freeway. However, the 500-year flood is not contained by the levee in this area, resulting in some overflow to the south. Back waters from this 500-year overflow are impounded by the Midtown Freeway and Armour Road. No flood protection measures exist for Rock Creek at the present time (Reference 16). City of Northmoor: No planned flood control measures have been undertaken. Local channel improvements have been made by developers during construction of their developments, such as the shopping center (Reference 14). City of Parkville: Riss Lake is a dammed water body on White Aloe Branch and is the only flood control measure presently in place in Parkville; no other projects are on an active list. Its storage potential reduces flow downstream. Flood warning and forecasting services for the city are performed by the National Oceanic and Atmospheric Administration/National Weather Service, which, in turn, alerts the news media and local officials when serious flooding is imminent (Reference 12). City of Riverside: The Quindaro Bend Levee District, in conjunction with the USACE, constructed an industrial-type levee adjacent to the Missouri River. The Riverside-Quindaro Bend Levee (MRLS 385-L) is an accredited levee providing protection from the 1-percent-annual-chance or greater flood hazard. The area, presently zoned for industry, is considered quite controversial. An agricultural levee located adjacent to the Missouri River protects this floodprone area only from annual floods and has no effect on the floods of the frequencies in this study. Presently, the only provision for controlling development along flood-prone creeks is the city's Master Plan, completed by the Mid- America Regional Council in Floodprone areas have been delineated on the Master Plan as conservation or park areas. Along Burlington Creek, Platte County and a local developer have performed limited dredging of the creek channel, and have removed the bridge at the ingress to Paradise Valley Road. This bridge was considered an obstruction to water flow. These provisions seemed to have helped the situation, as evidenced by heavy rains in April and September of 1975 which did little damage. However, because silting of the channel occurs so quickly, these provisions would not be adequate for future protection. No flood control measures, other than local channel improvements made by developers during construction, exist along Line Creek. Flood warning and forecasting services for the city are performed by the National Oceanic and Atmospheric Administration (NOAA), National Weather Service, which in turn alerts the news media and local officials when serious flooding is imminent (Reference 11). City of Tracy: The USACE have just completed construction of Smithville Dam on the Little Platte River. The Little Platte River is a large tributary of the Platte River with its confluence upstream of Tracy. The effect of the dam will lower the 1-percent-annual discharge about 6,500 cubic feet per second (cfs), from 87,500 cfs to 81,000 cfs. No other planned flood control measures are actively being considered (Reference 13). City of Weston: No major flood control measures are planned for Weston. There are reservoirs upstream in existence and some private agricultural levees to protect the town. The Missouri River controls all the flooding on Bear Creek and the flooding is restricted due to the levees in place; 13