WSP00979 - Laserfiche WebLink

Home Browse Search

..........- c' \ .,.. "f.~ ~~ ".~ ",.." '..,~~~~..~. ;,!~/, ;,j&':,':. ":.:~~t ~,:.:.~ .~;,... . ~"~ ....... - -~ ....-..".~ '~2::: .~_,~ ......... ..:,~,~..... ~'t~ .' p'- ~ ~. . ;.............. _.-D Figur. B2-Continued. The Dugway Gage and the high.water mark from the 1921 flood (photographs by R.C, Rice, U.S, Geological Survey, September 22, 1921). (e) Downstream view of the high-water section of Ougway Gage painted on cliff next to dugway road. I.G. Cockcroft standing next to gage, High.water mark from the June 1921 flood visible on the cliff at a stage of 2648 feet on the gage (determined by levels on June 7, t922) This stage equals an elevation of 3,132,64 reet above the NGVD1929, August 10, 1922 I.G. Cockcroft and Elmer Johnson first tied the elevation of the July 7, 1884. Ilood peak into the Dugway Gage, The 1884 Ilood was the most recent Ilood prior to the June 1921 Ilood that was larger than the 1921 flood, The high-water mark was a crotch in a peach tree at the Lonely Dell Ranch (on river right below the Dugway Gage) from which Jerry Johnson rescued a cottontail rabbit. The cDlrected NGVO 1929 elevation of this mark was 3. 136.90 ft. which equals 30.74 ft above the datum of the Dugway Gage. The elevation of the stump of this tree near Johnson's house was checked by levels by W,E. Dickinson on September 22. 1924. On April 13. 1938, J.S. Gatewood estimated that the peak stage of the 18841lood would have been at a stage of about 31.5 ft on the Dugway Gage. However. because the water-surface slope during the 1921 Ilood was between 0,0000 I and 0,00003 hetween the Dugway Gage and the Lonely Dell Ranch, and it is likely that the water-sllIface slope was even lower during the 1884 !lood (because of Ilattening of the water surface in this reach with increasing stage, as shown in this study). the peak stage of the 1884 Ilood was probably no more than 31 ti on the Dugway Gage. LG. Cockcroft installed a new vet1icallow-water section for the Dugway Gage to replace the old one that had "torn loose." Cockcroft stated that the "new vertical reads 1/2 tenth lower." Roger C. Rice stated that Cockcroft probably installed this new staff gage slightly lower than the original one so that the readings on it and on the lower end of the inclined middle section would agree, Although the original vertical low-water and inclined upper sections were installed relative to the same datum, stage readings tended to be about 0,05 ft lower on the original vertical low-water section than on the inclined middle section, June 7,1922 , , f\"'~!~ Appendix B 73