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<br />I
<br />I.
<br />
<br />
<br />The following individuals participated in
<br />information
<br />
<br />meetings, providing valuable Insights and
<br />
<br />1-1
<br />
<br />the project
<br />
<br />1
<br />
<br />3
<br />
<br />Mapping and Surveys
<br />
<br />The
<br />
<br />1
<br />
<br />The major drainageway analysis was performed in accordance with the Jefferson County Storm
<br />Drainage Design and Technical Criteria (Reference 3) and the Urban Storm Drainage Criteria Manua
<br />(Reference 4).
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<br />6
<br />
<br />Acknowledgments
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<br />.
<br />
<br />100-year
<br />
<br />water
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<br />1
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<br />5
<br />
<br />Analysis and Design Criteria
<br />
<br />Technical Appendix for Letter of Map Revision, Muller
<br />1990
<br />
<br />Engineering Company, me,
<br />
<br />Revise July
<br />
<br />11
<br />
<br />Design Report for North Tributary of Massey Draw Drainage Improvements,
<br />Company, Inc., January 1986
<br />
<br />'I'
<br />
<br />The purpose of the Massey Draw and SJCD (South)
<br />Hazard Area Delineation (FHAD) is to:
<br />
<br />Muller
<br />
<br />Engineering
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<br />
<br />Since the Original Plan was prepared, the Ken Caryl Ranch area west of the hogback (and C-470) has
<br />been developed, the Natural Resources Conservation Service (NRCS), formerly Soil Conservation
<br />Service, produced more detailed soils maps that indicated substantially lower infiltration rates west of
<br />the hogback, and new hydrologic modeling methodologies have been adopted. The combination of
<br />these factors resulted in significantly increased flow rates at the hogback, In 1982, the Massey Draw
<br />hydrology was updated, which resulted in the 1 OO-year flows being increased from 23 percent to 211
<br />percent at various points along Massey Draw. In addition, Jefferson County, UDFCD, and private
<br />developers have constructed drainage improvements in both watersheds.
<br />
<br />Major
<br />
<br />Drainageway Planning Update. Flood
<br />
<br />The Meadows Sanctuary, J,F, Sato & Associates
<br />
<br />Regional Detention Study for Massey Draw from Ken-Caryl Avenue to Kipling Parkway, JR
<br />Engineering, lTD., Revised March 16, 1998
<br />
<br />Map Works prepared topographic mapping for the project under separate contract with UDFCD
<br />maps were compiled and prepared at a scale of 1" = 1 00' with 2-foot contour intervals. The
<br />topography was compiled from aerial photographs taken on September 2, 2003. The project mapping
<br />is based on the NA VD 1988 vertical datum and the NAD 1983 horizontal datum. The maps were
<br />submitted in an AutoCAD Version 2000 drawing format. Base maps for the hydrologic maps consist of
<br />
<br />nc.
<br />
<br />Revised September 8
<br />
<br />997
<br />
<br />"The Valley," Massey Draw North Village Tributary, Extension of 1 00- Year Flood Plain Study, Muller
<br />Engineering Company, Inc" November 22. 1985
<br />
<br />/1
<br />
<br />I
<br />
<br />The project study area consists of the Massey Draw and SJCD (South) watersheds and is presented in
<br />Figure 1. Except for the North Tributary of SJCD (South), both watersheds were originally studied in
<br />1979. The study results were presented in a report titled Flood Hazard Area Delineation, Massey
<br />Draw & North Tributary, SJCD (South) 6200 & Tributaries (Original Plan, Reference 1), The North
<br />Tributary of SJCD (South) was studied in 1976 and the results were presented in the major
<br />drainageway planning study for SJCD (North)-Basin 6100 (Reference 2). The North Tributary of
<br />SJCD (South) is included in the scope of the masterplan update,
<br />
<br />'The Valley," Massey Draw North Village Tributary
<br />Company, Inc" May 1984
<br />
<br />100-Year Flood Plain Study, MUlier Engineering
<br />
<br />Revised Preliminary Stormwater Detention Study, "The Valley," Muller
<br />September 1982
<br />
<br />Define the water surface profiles for the 1 0-, 50-, 100- and 500-year storm events.
<br />Define two floodways, based on encroachment resulting in maximum increases of the energy
<br />gradeline of 0.5 foot and 1.0 foot.
<br />Prepare plan and profile drawings showing the 1 OO-year floodplain and 10- and
<br />surface profiles.
<br />Preparation of a FHAD report.
<br />
<br />Engineering Company, Inc,
<br />
<br />Design Report for the Channelization of Massey Draw Between Garrison Street and South Carr
<br />Street, MSM Consultants, Inc" March 1981
<br />
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<br />,
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<br />~I
<br />
<br />1
<br />
<br />This report is part of a study co-sponsored by Urban Drainage and Flood Control District (UDFCD),
<br />Jefferson County and the City of Littleton. The Agreement Regarding Major Drainageway Planning for
<br />Massey Draw and SJCD (South) Drainageways Update (Agreement No, 03-08,06) was executed on
<br />December 8, 2003. Addendum No, 1 subsequently amended the agreement to include a Flood
<br />Hazard Area Delineation (FHAD) Study. Addendum No, 1 was executed on January 2, 2004.
<br />Addendum No, 2, executed June 16, 2004, amended the agreement to include additional topographic
<br />surveying. Addendum No, 3, executed July 21, 2004, amended the agreement to include additional
<br />investigation and analyses related to the June 27,2004 flood on Massey Draw,
<br />
<br />2
<br />
<br />Purpose and Scope
<br />
<br />Final Drainage Report for Wingate South
<br />
<br />In addition to
<br />has occurred
<br />
<br />Background Information
<br />
<br />1
<br />
<br />USGS 7.5-minute quadrangle sheets and 30 meter digital elevation models obtained from the U,S
<br />Geological Survey. Soil surveys were obtained from the Natural Resource Conservation Service,
<br />land use information was obtained from the Jefferson County IT Development Department. An
<br />inventory of drainage structures completed by JR Engineering in December 2003 contains information
<br />on culverts in the watershed.
<br />
<br />4
<br />
<br />Final Stormwater Detention Study, "The Valley," Muller
<br />1984
<br />
<br />the Original Plan, the project sponsors provided studies related
<br />in the study area. which included
<br />
<br />MSM Consultants
<br />
<br />Engineering Company
<br />
<br />the development that
<br />
<br />nc.
<br />
<br />March
<br />
<br />1981
<br />
<br />to
<br />
<br />nc
<br />
<br />Revised May 5
<br />
<br />1
<br />
<br />1
<br />
<br />Authorization
<br />
<br />I
<br />
<br />I
<br />
<br />I
<br />
<br />1.
<br />
<br />
<br />Introduction
<br />
<br />CIty 0/' Littleton
<br />
<br />
<br />Flood Hazard Area Delineation
<br />Massey Draw and SJCD (South)
<br />December 2005
<br />
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