FLOOD09863

• County: Boulder
• Community: Longmont
• Stream Name: St. Vrain Creek
• Basin: South Platte
• Title: St. Vrain Creek Hydrology
• Date: 7/10/1985
• Prepared For: Boulder County
• Prepared By: Engineering Professionals
• Floodplain - Doc Type: Floodplain Report/Masterplan

11,900 cfs 500 yr.
5,430 cfs 100 yr. ~
3,750 cfs 50 yr.
1,400 cfs 10 yr.
92 sq. Qi. drainage area

20,260 cfs 500 yr.
~8,880 cfs 100 yr.
5,570 cfs 50 yr.
2,040 cfs 10 yr.
211 sq. Qi. drainage area

... Saint Vrain Creek ...
~requencY-Flow Schematic

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Lyons -

10,630 cfs 500 yr.
--J, 4,310 cfs 100 yr.
2,850 cfs 50 yr.
1,000 cfs 10 yr.
119 sq. mi . drainage area

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North 85th

Street

Study Urni t
~9'680 cfs 500 yr.
9,580 cfs 100 yr.
6,890 cfs 50 yr.
3,160 cfs 10 yr.
241 sq. rni. drainage area

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Longmont\

Boul der County
Wel d County

28,670 cfs 5qO yr.
14,850 cfs 100 yr.
10,950 cfs 50 yr.
5,250 cfs 10 yr.
351 sq. mi. drainage area