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Kannah Creek Mesa County, Colorado Floodplain Information Report 2 ------------------- -------- ---------- EVENTS ANALYZED ORDERED EVENTS FLOW WATER FLOW WEIBULL MON DAY YEAR CFS RANK YEAR CFS PLOT POS 0 0 1918 556. 1 1921 1640. 1. 82 0 0 1919 601. 2 1920 1360. 3.64 0 0 1920 1360. 3 1935 1300. 5.45 0 0 1921 1640. 4 1933 1020. 7.27 0 0 1933 1020. 5 1948 1010. 9.09 0 0 1934 264. 6 1938 992. 10.91 0 0 1935 1300. 7 1957 772. 12.73 0 0 1936 448. 8 1964 760. 14.55 0 0 1937 734. 9 1944 757. 16.36 0 0 1938 992. 10 1942 735. 18.18 0 0 1939 448. 11 1937 734. 20.00 0 0 1940 700. 12 1958 726. 21.82 0 0 1941 517. 13 1947 724. 23.64 0 0 1942 735. 14 1945 720. 25.45 0 0 1943 569. 15 1940 700. 27.27 0 0 1944 757. 16 1965 700. 29.09 0 0 1945 720. 17 1951 675. 30.91 0 0 1946 504. 18 1955 634. 32.73 II 0 0 1947 724. I 19 1980 627. 34.55 II 0 0 1948 1010. 20 1953 611. 36.36 0 0 1949 582. 21 1919 601. 38.18 0 0 1950 538. 22 1949 582. 40.00 0 0 1951 675. 23 1943 569. 41.82 0 0 1952 520. 24 1978 561. 43.64 0 0 1953 611. 25 1962 559. 45.45 0 0 1954 351. 26 1918 556. 47.27 0 0 1955 634. 27 1975 550. 49.09 0 0 1956 514. 28 1950 538. 50.91 0 0 1957 772. 29 1968 534. 52.73 0 0 1958 726. 30 1982 533. 54.55 0 0 1959 456. 31 1970 528. 56.36 0 0 1960 379. 32 1952 520. 58.18 0 0 1961 419. 33 1941 517. 60.00 0 0 1962 559. 34 1956 514. 61.82 0 0 1963 356. 35 1946 504. 63.64 0 0 1964 760. 36 1973 476. 65.45 0 0 1965 700. 37 1959 456. 67.27 0 0 1966 352. 38 1939 448. 69.09 0 0 1967 304. 39 1936 448. 70.91 0 0 1968 534. 40 1979 448. 72.73 0 0 1969 304. 41 1961 419. 74.55 0 0 1970 528. 42 1974 414. 76.36 0 0 1971 290. 43 1960 379. 78.18 0 0 1972 164. 44 1963 356. 80.00 0 0 1973 476. 45 1976 356. 81.82 0 0 1974 414. 46 1966 352. 83.64 0 0 1975 550. 47 1954 351. 85.45 0 0 1976 356. 48 1967 304. 87.27 0 0 1977 285. 49 1969 304. 89.09 0 0 1978 561. 50 1981 291. 90.91 0 0 1979 448. 51 1971 290. 92.73 0 0 1980 627. 52 1977 285. 94.55 0 0 1981 291. 53 1934 264. 96.36 L~~----=982 _-----==~L____=_~ 197~__ 164 . _~ . 18 ~ ------------------- GAGE DATA TABLE 2 Ga2e Data The USGS operated and maintained Gage #09152000 "KANNAH CREEK NEAR WHITEW ATER, COLORADO" midway up the basin for the years 1918 through 1921, and 1933 through 1982. A total of 54 years of data is available. According to the USGS, the gage was located at Latitude 38057'42", Longitude 108013'47" NAD27, with a USGS reported drainage area 61.90 square miles. The gage datum is reported as 6,060.00 feet above sea level NGVD29. Recorded annual peak flow gage data is reported in the adjacent table. The greatest flow on record was 1921 at 1640 cfs Using the data, the Corps of Engineers Hydrologic Engineering Center - Flood Frequency Analysis (HEC-FFA) program was run to determine the computed probability for a 100-year event (1% exceedance) of 1260 to 1860 cfs at the gage (Junction 4 in the HEC-HMS model). This result was used for calibration of the HEC-HMS model at the midpoint of the basin. The results of the HEC-FAA model was not used in the floodplain hydrology, and provided for comparison and information purposes only FLOOD FREQUENCY ANALYSIS COMPUTED EXPECTED PERCENT CONFIDENCE LIMITS CURVE PROBABILITY CHANCE .05 .95 FLOW IN CFS EXCEEDANCE FLOW IN CFS 1890. 2030. .2 2460. 1560. 1660. 1750. .5 2110. 1390. 1490. 1550. 1.0 1860. 1260. 1320. 1370. 2.0 1620. 1140. 1110. 1130. 5.0 1320. 969. 947. 958. 10.0 1100. 840. 782. 787. 20.0 886. 703. 542. 542. 50.0 599. 49l. 376. 374. 80.0 418. 332. 311. 307. 90.0 350. 268. 265. 260. 95.0 304. 224. 197. 189. 99.0 233. 159. SYSTEMATIC STATISTICS LOG TRANSFORM: FLOW, CFS NUMBER OF EVENTS MEAN 2.7343 HISTORIC EVENTS 0 STANDARD DEV .1887 HIGH OUTLIERS 0 COMPUTED SKEW .0389 LOW OUTLIERS 0 REGIONAL SKEW .0000 ZERO OR MISSING 0 ADOPTED SKEW .0000 SYSTEMATIC EVENTS 54 1 TABLE