FLOOD06193

• County: Alamosa
• Community: Alamosa County
• Stream Name: Rock Creek, Gato Creek, Zapata Creek
• Basin: Rio Grande
• Title: Report on Hydrologic Investigations FIS Alamosa County
• Date: 12/1/1975
• Prepared For: Alamosa County
• Prepared By: US Army Corps of Engineers
• Floodplain - Doc Type: Floodplain Report/Masterplan

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REPORT ON HYDROLOGIC INVESTIGATIONS
FLOOD INSURANCE STUDY
ALAMOSA COUNTY, COLORADO

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1. Purpose, The purpose of this report is to present the basis and
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results of the hydrologic analysis required for a flood insurance study

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of areas in Alamosa County, Colorado subject to flooding from runoff

from Rock Creek, Gato Creek. and tributaries and from North. Middle,

and South Zapata Creeks and tributaries. Another area-about 3 miles

northwest of Alamosa on Highway 285 to Monte Vista was ,also studied,

Maps showing these areas are presented as plates land 2.,

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2, This report presents the results of a regional frequency study

which provides the basis for developing flow frequency parameters for

mountain areas in the vicinity of Alamosa, Colorado where flooding is

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predominantly caused by spring snowmelt runoff. For the flatter plains,

or plateau areas where flooding can result from snowmelt, rainfall, or

'a combination of both, flow frequency parameters were developed from

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"Manual for Estimating Flood Characteristics of Natural-Flow Streams

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in Colorado" by Jerald F. McCain and Robert D, Jarett, U,S. Geological

Survey,

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3, Basin Characteristics. Alamosa County is located in the San Luis

Valley in Colorado, The valley which rises east of the'Co~tinental

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Divide on the flanks of the San Juan Mountains is an open, almost tree-

less alluvial plain appearing almost perfectly flat, The valley all

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