«MEEKER COUNTY, MINNESOTA AND INCORPORATED AREAS Community Community Name Number CEDAR MILLS, CITY OF 270281 COSMOS, CITY OF 270282 *DARWIN, CITY OF ...»
AND INCORPORATED AREAS
CEDAR MILLS, CITY OF 270281
COSMOS, CITY OF 270282
*DARWIN, CITY OF 275318
*DASSEL, CITY OF 275316
*EDEN VALLEY, CITY OF 270283
*GROVE CITY, CITY OF 275317
KINGSTON, CITY OF 270284 LITCHFIELD, CITY OF 270285 MEEKER COUNTY 270280 (UNINCORPORATED AREAS) WATKINS, CITY OF 270286 *No Special Flood Hazard Areas Identified Meeker County Effective: April 3, 2012
FLOOD INSURANCE STUDY NUMBER27093CV000A NOTICE TO
FLOOD INSURANCE STUDY USERSCommunities 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 (FIS) report may not contain all data available within the Community Map Repository. Please contact the Community Map Repository for any additional data.
The Federal Emergency Management Agency (FEMA) may revise and republish part or all of this FIS report at any time. In addition, FEMA may revise part of this FIS report by the Letter of Map Revision process, which does not involve republication or redistribution of the FIS report. Therefore, users should consult with community officials and check the Community Map Repository to obtain the most current FIS report components.
Selected Flood Insurance Rate Map panels for this 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(s) New Zone C X Initial Countywide FIS Effective Date: April 3, 2012
TABLE OF CONTENTSINTRODUCTION
1.1 Purpose of Study
1.2 Authority and Acknowledgments
2.1 Scope of Study
2.2 Community Description
2.3 Principal Flood Problems
2.4 Flood Protection Measures
3.1 Hydrologic Analyses
3.2 Hydraulic Analyses
3.3 Vertical Datum
FLOODPLAIN MANAGEMENT APPLICATIONS
4.1 Floodplain Boundaries
5.0 FLOOD INSURANCE RATE MAP
6.0 OTHER STUDIES
7.0 LOCATION OF DATA
8.0 BIBLIOGRAPHY AND REFERENCES
Table 1 – Summary of Discharges
Table 2 – Summary of Stillwater Elevations
Table 3 – Vertical Datum Conversion
Table 4 – Floodway Data
Table 5 – Community Map History
This Flood Insurance Study (FIS) revises and updates information on the existence and severity of flood hazards in the geographic area of Meeker County, including the Cities of Cedar Mills, Cosmos, Darwin, Dassel, Eden Valley, Grove City, Kingston, Litchfield and Watkins; and the unincorporated areas of Meeker County (referred to collectively herein as Meeker County), and aids in the administration of the National Flood Insurance Act of 1968 and the Flood Disaster Protection Act of 1973. 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 CFR, 60.3.
Please note that the City of Eden Valley is geographically located in Meeker and Stearns Counties. Only the Meeker County portion of the City of Eden Valley is included in this FIS report. See the separately published FIS report and Flood Insurance Rate Map (FIRM) for flood-hazard information.
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.
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 the Federal Emergency Management Agency (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.
Precountywide Analyses Information on the authority and acknowledgements for each jurisdiction included in this countywide FIS, as compiled from their previously printed FIS reports, is
The Cities of Cedar Mills, Cosmos, Darwin, Dassel, Eden Valley, Grove City, Kingston, and Watkins and Meeker County (Unincorporated Areas) have no previously printed FIS reports.
This Countywide FIS Report The hydrologic and hydraulic analyses for this study were performed by the Minnesota Department of Natural Resources (MNDNR) for FEMA, under Contract No. HSFE05-05-D-023. The work was completed in June 2010.
Selected approximate analyses for flooding sources for this analysis were developed by Atkins.
Base map information shown on the Flood Insurance Rate Map (FIRM) was provided in digital format by Farm Services Administration. This information was photogrammetrically compiled at a scale of 1:12,000 from aerial photography dated 2009 or later. The projection used in the preparation of this map is Universal Transverse Mercator (UTM) Zone 15, and the horizontal datum used is North American Datum of 1983 (NAD 83), Geodetic Reference System (GRS) 1980 spheroid.
An initial meeting is held with representatives from FEMA, the community, and the study contractor to explain the nature and purpose of a FIS, and to identify the streams to be studied or restudied. A final meeting is held with representatives from FEMA, the community, and the study contractor to review the results of the study.
The initial and final meeting dates for previous FIS reports for Meeker County
and its communities are listed in the following table:
The initial meeting was held on July 26, 2005, and attended by representatives of FEMA, MNDNR, Barr Engineering, Meeker County, and Atkins.
The results of the study were reviewed at the final meeting held on December 15, 2010, and attended by representatives of FEMA, Meeker County, and Atkins; as well as representatives of the Cities of Dassel, Eden Valley, Grove City, Kingston, Litchfield, and Watkins. All issues and/or concerns raised at that meeting have been addressed.
2.0 AREA STUDIED
This FIS covers the geographic area of Meeker County, Minnesota, 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.
For this countywide FIS, all streams studied by approximate methods were updated or newly studied to better match existing topography.
The following streams are studied by limited detailed methods in this FIS report:
For this countywide FIS, the FIS report and FIRM were converted to countywide format, and the flooding information for the entire county, including both incorporated and unincorporated areas, is shown. Also, the vertical datum was converted from the National Geodetic Vertical Datum of 1929 (NGVD) to the North American Vertical Datum of 1988 (NAVD). In addition, the Universal Transverse Mercator coordinates, previously referenced to the North American Datum of 1927 (NAD27), are now referenced to the NAD83.
Approximate analyses were used to study those areas having low development potential or minimal flood hazards. The scope and methods of study were proposed to and agreed upon by FEMA and Meeker County.
2.2 Community Description Meeker County is located in central Minnesota. Meeker County is 70 miles west of the Minneapolis-St. Paul metropolitan area; 60 miles north of New Ulm; and 180 miles southwest of Duluth. It is bordered on the southwest by Renville County, the southeast by McLeod County, on the north by Stearns County, on the east by Wright County, and on the west by Kandiyohi County. Meeker County has a total land area of 457,100 acres, with about 4,840 areas of this area being water. According to the Soil Conservation Service (SCS), now the Natural Resources Conservation Service, approximately 75-percent of the area in the county is cropland (SCS, 1968). According to the U.S. Census Bureau in 2009, the estimated population for Meeker County was 23,154 (U.S. Census Bureau, 2010).
The climate of Meeker County is continental with average temperatures ranging from 2 degrees Fahrenheit (°F) to 21°F in January and from 61°F to 83°F in July.
The average annual precipitation is 27.5 inches. Precipitation is well distributed throughout the growing season; 18.1 inches or 65.7 percent of the total annual precipitation occurs during the growing season. Snowfall averages 40.8 inches annually (High Plains Regional Climate Center, 2010).
The topography of Meeker County is mostly gently sloping but ranges from nearly level to very steep. The soils formed in silty and clayey glacial lacustrine sediments; in loamy, silty, and clayey glacial till; and in glacial outwash with a thin mantle of loamy sediment. Native vegetation in the southwestern part of the county was mainly tall prairie grasses, and native vegetation in the southeastern and northern parts of the county supported mixed northern hardwoods. Nearly all of the depressions in the county are lakes or marshes covered with reeds, sedges, and other wetland species (SCS, 1968).
2.3 Principal Flood Problems The principal flood problem in the City of Litchfield has been the overflow of the banks of Jewett Creek.
Lake Ripley has a weir outlet structure with a fixed crest. The lake provides significant flood attenuation due to the storage volume relative to the contributing drainage area. The lake effectively reduces peak flows on Jewett Creek through the City of Litchfield.
3.0 ENGINEERING METHODS For the flooding sources studied by detailed methods in the community, standard hydrologic and hydraulic study methods were used to determine the flood hazard data required for this study. Flood events of a magnitude that are expected to be equaled or exceeded once on the average during any 10-, 50-, 100-, or 500-year period (recurrence interval) have been selected as having special significance for floodplain management and for flood insurance rates. These events, commonly termed the 10-, 50-, 100-, and 500-year floods, have a 10-, 2-, 1-, and 0.2-percent chance, respectively, of being equaled or exceeded during any year. Although the recurrence interval represents the long-term, average period between floods of a specific magnitude, rare floods could occur at short intervals or even within the same year. The risk of experiencing a rare flood increases when periods greater than 1 year are considered. For example, the risk of having a flood that equals or exceeds the 1-percent-annual-chance (100-year) flood in any 50-year period is approximately 40 percent (4 in 10); for any 90-year period, the risk increases to approximately 60 percent (6 in 10). The analyses reported herein reflect flooding potentials based on conditions existing in the community at the time of completion of this study. Maps and flood elevations will be amended periodically to reflect future changes.
Hydrologic analyses were carried out to establish peak discharge-frequency relationships for each flooding source studied by detailed methods affecting the community.
The 10-percent and 1-percent-annual-chance flood elevations and outflow from Lake Ripley were determined using the SCS computer program, TR-20 (SCS, 1965). The drainage area above the outlet of Lake Ripley is 13.6 square miles.
The tributaries to Lake Ripley have a relatively flat average slope of 0.34 percent.
Marshes and lakes comprise 30 percent of the total drainage area. Inflow to Lake Ripley is primarily from three small streams draining to the lake from the south.
The flood storage pool of Lake Ripley is sufficient to provide considerable attenuation to flood flows entering the lake. Flow out of Lake Ripley is controlled by a weir under the bridge on Pleasure Drive, a street along the north side of the lake. Flows in County Ditch 19 and in Jewett Creek were determined by extending the TR-20 model downstream to State Highway 24 just north of the
Hydrologic data was developed using the USGS computer program, PF32, (USGS,