FLOOD04639

• County: Las Animas
• Community: Trinidad
• Stream Name: Pinon Canon Dam
• Basin: Arkansas
• Title: Pinon canaon Dam Flood Control
• Date: 10/1/1951
• Prepared For: CWCB
• Prepared By: COE
• Floodplain - Doc Type: Project

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Appendix I

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PROJECT .REPORT,~ '
.ON'
PINON CANON DAM.
TRINIDAD, COLORADO

APPEND1X I

HYDROLOGY

I - INTRODUCTION

l-oi;. Purp=. - The purpose of this appendix is to present basic
hydrologie data used in developing the project. plan for Pinon Canon Dam
on Pinon Canon L!>r-ayo at Trinidad, Colorado.

II - ,{ATERSHED CHIlRACTERISrrCS

2-01. Climate..- The hnon Canon Arroyo drainage basin at Trinidad
.is eharacterized by intense .10cal thunderstorms in summer and moderi'-te
to heavy snowfall in winter months. The change from summer to winter is
cl.}araeterized:by the sudden disappearanee of thunderstorm activity fol-
lowed. by the clear winter weather that dominates this area between
frontal passageS. Storms. during the sUllll1ler months are usually of the
thunderstorm type and are most active during JUly and August. These
thunderstorms, eaused by orographic lifting, usually reach their maximum
intensity in late afternoon and evening and are often aecompanied qy
very heavy loeal showers..' The mean annual temperature at Trinidad as
indicated by 47 years of intermittent record is 52 degrees.Fahrenheit
with a maximum of 99 degrees. and a minimum of -26 degrees. 'fhe .basin
is eharaeterized by low relative humidity and the average is about
52 percent. The prevailing wind at Trinidad is westerly with the
greatest wind movement occurring during the spring months. The maxi-
mum wind velocity reeorded at the nearest first order, U. S. Weather
Bureau Station, Pueblo, Colorado, was 58 miles per hour from the
northwest. This station shows a wind movement similar to that at
Trinidad, Colorado.

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2-02. Preeipitation. - The average annual precipitation at
Trinidad, Colorado, based on 52 years of record, is 16.83 inches. . The
greatest precipitation occurs during the sp~ing and summer months,
April - August, averaging about 6lpercent of.the total. . The maximum
reeorded 24-hour precipitation at Trinidad was 3.73 inehessnd oc-.
curred 1 Septembe~ 1942. The average annual snowfall is5}.4 inches,
with a maximum annual, of 118.5 inehes and a minimum of lq.O inches,

2-03~. Floods. - Flood producing storMs over. the Pinon Canon
drainage area are generally of the thunderstorm type and occur during