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

I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I

TABLE 7
FLOOD FREQUENCY-ELEVATION AND DISCHARGE DATA
Lefthand Creek Boulder County, Colorado
Distance StreaJi. 10-Year 50- Year 100-Year 500-Year
Reference From Bed Flood Peak 2 Flood Peak 2 Flood Peak 2 Flood Peak 2
Point Mouth Elevation Elevation Discharge-L Elevation Discharge-L Elevation Discharge-L Elevation Discharge -1..
Nwnber Ft. Identification Ft. -m. 5.1. Ft.-m.s.l. c. f.S. Ft. -m. 5.1. c.f.s. Ft.-m.s.l. c. f. s. Ft.-m.s.l. c.f.s.
0+00 Mouth 4915.2
4 4+50 4918.8 4922.9 520 4926.5 2480 4927.3 4610 4928.0 10320
5 8+10 4919.7 4924.0 4928.0 4928.6 4929.5
5.1 9+00 4920.7 4924.2 4928.0 4928.7 4930.2
5.2 9+10 Diversion Structure 4925.0 d/s 4924.2 d/s 4928.0 d/s 4928.7 d/s 4930.2
u/s 4927.3 u/s 4930.3 u/s 4930.7 u/s 4931.2
5.3 9+20 4922.9 4927.3 4930.3 4930.7 4931. 2
6 12+90 4924.8 4928.4 4931.4 4931. 8 4932.5
6.1 20+25 4929.3 4932.4 4935.9 4936.3 4936.9
7 20+75 Private Drive 4929.5 d/s 4932.4 d/s 4935.9 d/s 4936.3 d/s 4936.9
u/s 4936.0 u/s 4936.7 u/s 4937.1 u/s 4937.8
8 21+00 4929.8 4936.0 4936.7 4937.1 4937.8
9 25+90 4930.8 4936.3 4937.9 4939.0 4939.5
10 33+40 4931.8 4937.6 4941. 0 4941.6 4942.5
11 37+10 4933.1 4938.4 4941.8 4942.6 4943.4
12 45+40 4936.4 4940.7 4944.4 4945.7 4948.0
13 52+90 4939.0 4943.5 4947.7 4950.7 4952.9
14 55+00 North 107th Street 4939.5 d/s 4943.5 d/s 4947.7 d/s 4950,7 d/s 4952.9
u/s 4945.3 u/s 4949.7 u/s 4952.1 u/s 4955.6
1/ Low water elevation as determined by aerial photogrammetric methods.
2/ Discharges are prorated between stations.

10