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HomeMy WebLinkAbout011 -Appendix K - Flood Analysis Memo 1105 REEVES ROAD WEST, SUITE 6 BOZEMAN, MT 59718 406-581-5730 www.headwatersmt.net Page 1 of 1 Diamond 8 Baxter Creek & Baxter Ditch Flood Analysis A flood hazard analysis for Baxter Creek and Baxter Ditch was completed for Northwest Crossing Subdivision by Morrison Maierle in September of 2019. According to this analysis, no part of the Diamond 8 development falls within the 100-year flood plain for Baxter Creek or Baxter Ditch. An exhibit showing our development, along with the analysis performed by Morrison Maierle, are attached for reference. Utilities will be installed under Touchstone Drive to feed the Diamond 8 site. The Baxter Creek crossing will be restored to preconstruction conditions following the installation of the water and sewer mains. The sewer main has over 4’ of separation from the creek bottom, and it will be encased in concrete to provide an additional layer of protection. The Baxter Ditch crossing will require a culvert to allow maintenance access to the sewer manholes. This culvert has been sized to pass the 100-year flood flows. The onsite unnamed waterway originates in a storm pond on the south side of Oak Street and therefore does not have a drainage basin. The offsite flows which will be carried down this waterway will be analyzed when sizing the culvert under Harvest Parkway and that culvert will be sized to pass the 100- year flows without roadway inundation. 10 W W W 8 W 8 W 8 W 8 W 8 W 8 W 8 W 8 W 8 W 8 W 21 SS 21 SS 21 SS 21 SS 21 SS 21 SS 21 SS 21 SS 21 SS 21 SS 21S 8W 21 SS 21 SS 21 SS 21 SS 21 SS 8 W 8 W 8 W 8 W 8 W 8 W 8 W 8 W 8 W 8 W 8 W 8 W 21 SS 21 SS 21 SS 21 SS 21 SS 21 SS 21 SS 21 SS 21 SS21 SS21 SS21 SS21 SS21 SS21 SS21 SS21 SSWSWSWSWSWS4 SS4 SS4 SS8 W 8 W 8 W 8 W 4 SS4 SS 4 SS 4 SS 4 SSWSWSWSWS 12 W12 W12 W12 W12 W12 W12 W12 W12 W12 W12 W12 W12 W12 W12 W12 W12 W12 W12 W12 W12 W12 W12 W12 W12 W12 W12 W12 W8 W 8 W8 W8 W8 W8 SS8 SS8 SS8 SS8 SS8 SS8 SS8 SS12 W 12 W 12 W 12 W 12 W 12 W 12 W 12 W 12 W 12 W 12 W 12 W 12 W U U UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU U U U U U U UUUUU10 SS10 SS10 SS10 SS8 W8 W8 W8 W8 W8 W8 W8 W8 W8 W10 SS10 SS10 SS10 SS10 SS10 SS10 SS10 SS10 SS10 SS15 SD 15 SD15 SD15 SD15 SD15 SD15 SD15 SD15 SD15 SD15 SD15 SD15 SD15 SD15 SD15 SD15 SD18 SDOHP OHP OHP OHP OHP OHP OHP OHP OHP OHP OHP OHP OHP OHP OHP OHP OHP OHP OHP OHP OHP OHP OHP OHP OHP OHP OHP OHP OHP OHP OHP OHP OHP OHP OHP OHP OHP OHP OHP OHP OHP OHP OHP OHP OHP OHP OHP OHP OHP OHP OHP OHP OHPOHP 10 W 10 W 10 W 10 W 10 W 10 W 10 W 10 W 10 W 10 W 10 W 10W 10W 10W 18SD 18SD 8 SS 8 SS G21S 8W SD SDSDSDSDSDSDSDSDSD SD SDSDSDSDSD SDN GRAPHIC SCALE 1 inch = ft. 0 ( IN FEET ) 60120 120 120 11"X17": 1"= 240 ft HEADWATERS PROJECT NUMBER DRAWING NUMBER DRAWN BY: DATE: 2026 VERIFY SCALE THESE PRINTS MAY BE REDUCED. LINE BELOW MEASURES ONE INCH ON ORIGINAL DRAWING. MODIFY SCALE ACCORDINGLYPlot Date: 2/26/2026 1:06 PM H:\2128\002\ACAD\SHEETS\EXHIBITS\FLOOD MAP.dwg © HEADWATERS ENGINEERING, INC. REVISION DATE: 1105 REEVES RD WEST, SUITE 6, BOZEMAN, MT 59718 HEADWATERSMT.NET 406-581-5730 PROJECT LOCATION MONTANA BOZEMAN 02/11/2026 DJH FLOOD EXHIBIT DIAMOND 8 2128.002 FLD-1 APPROXIMATE 100-YR FLOOD EXTENTS APPROXIMATE 100-YR FLOOD EXTENTS APPROXIMATE 100-YR FLOOD EXTENTS