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<br />. <br /> <br />. <br /> <br />. <br /> <br />0742 <br /> <br />. <br /> <br />is near the head of a canyon section, mile 122. Flood reports indicate <br /> <br /> <br />that damage from bank caving, which is prevalent, begins at about 5,000 <br /> <br /> <br />cubic feet per second. These estimates were based on the following <br /> <br /> <br />data: stream gaging records at Trinidad; channel and valley surveyed <br /> <br /> <br />sections and highwater marks; field notes obtained during flood flows; <br /> <br /> <br />and from aerial photographs taken in 1951. <br /> <br /> <br />15. Runoff records. - Seventeen stream gaging stations have been <br /> <br /> <br />operated on Purgatoire River and tributaries. Most of these were staff <br /> <br /> <br />or chain gage reading only and no discharge records are available. Prior <br /> <br /> <br />to 1930, four of these stations were operated as river flood warning <br /> <br /> <br />stations by the U. S. Weather Bureau and records of river stage only <br /> <br /> <br />are available. itecords prior to 1921 at stream gaging stations <br /> <br /> <br />operated by other agencies were of the staff or chain gaging type but <br /> <br /> <br />the majority of the gages operated subsequent to 1921 have been of the <br /> <br /> <br />recording type. There are no discharge records available in the water- <br /> <br /> <br />shed above Trinidad, consequently, only the significant stations at <br /> <br /> <br />Trinidad and downstream points are considered. The maximum and minimum <br /> <br /> <br />stages and other pertinent data for these gaging stations are shown in <br /> <br /> <br />table 9. Location of gages above San Francisco Creek is shown on plate 1. <br /> <br /> <br />16. Discharge records are available for 12 or more complete <br /> <br /> <br />water years at the gaging stations listed in table 9. The mean annual <br /> <br /> <br />runoff and other pertinent data for these gages are shown in table 10. <br /> <br /> <br />The average annual water year runoff of Purgatoire River at Trinidad, <br /> <br /> <br />Colorado, for the 31 years of complete record, is 66,900 acre-feet; of <br /> <br /> <br />this amount 76 percent occurs during the period April through August. <br /> <br /> <br />In addition it is estimated that an average of about 25,000 acre-feet <br /> <br /> <br />per year is diverted for irrigation purposes upstream from Trinidad. <br /> <br />l5 <br /> <br />APl-'ENDIX B <br /> <br />