FLOOD00987

• Designation Number: 186
• County: Boulder
• Community: Longmont
• Stream Name: Lefthand Creek
• Title: Floodplain Information Report - Lefthand Creek, Volume I: Mouth to Foothills Highway, Boulder County and Longmont
• Date: 12/1/1981
• Designation Date: 4/1/1982
• Floodplain - Doc Type: Floodplain Report/Masterplan

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TABLE 7 (Continued)
FLOOD FREQUENCY-ELEVATION AND DISCHARGE DATA
Lefthand Creek Boulder County. Colorado
Di st ance Stream!L 10-Year 50-Year 100-Year 500-Year
Reference From Bed Flood Peak 21 Fl ood Peak 2 Flood Peak 2 Flood Peak 2
Point Mouth Elevation Elevation Discharge- Elevation Discharge-L Elevation Discharge-L Elevation Discharge--L
Number Ft. Identification Ft.-m.s.l. Ft.-m.s.l. c.f.s. Ft.-m.s.l. c.f. s. Ft.-m.s.l. c. f.s. Ft.-m.s.l. c. f. 5
66.1 287+30 5040.0 5043.8 5046.6 5048.4 5051.7
67 287+60 N. 8lst Street 5040.4 dls 5043.8 dls 5046.6 dls 5048.4 dls 5051. 7
u/s 5044.5 u/s 5048.1 u/s 5051. 6 u/s 5053.8
68 287+70 5040.4 5044.5 5048.1 5051.6 5053.8
69 293+35 5041. 6 5046.7 5051. 3 5053.6 5055.6
70 303+40 5046.9 5050.7 5053.9 5055.9 5058.4
71 312+40 5051. 2 5055.1 5057.9 5059.7 5062.5
72 319+65 5055.0 5058.4 5061. 1 5062.6 5065.0
73 324+ 10 5056.8 5060.5 5063.6 5065.1 5067.2
74 330+90 5059.2 5063.8 5067.6 5069.2 5070.7
75 336+80 5064.9 5068.0 5070.5 5071. 6 5073.3
75.1 344+45 5068.7 5072. 1 5074.3 5075.5 5077.5
76 344+90 N. 73rd Street 5069.0 dls 5072.1 750 dls 5074.3 3500 dls 5075.5 6330 dls 5077.5 13990
u/s 5072.9 u/s 5077.8 u/s 5080.6 u/s 5081.4
77 345+ 10 5069.0 5072.9 5077 .8 5080.6 5081.4 )
78 356+80 5079.0 5082.8 5084.4 5085.3 5086.8
80 370+65 5090.7 5094.2 5095.8 5096.4 5097.4
81 380+95 5098.8 5102.4 5103.9 5104.8 5106.0
81.1 386+20 5100.8 5104.7 5106.6 5107.8 5108.9
II Low water elevation as determined by aerial photogrammetric methods.
21 Discharges are prorated between stations.

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