|
<br />APPENDIX E
<br />
<br />( The floed of JWle 1927 was the highest on record in the San Luis
<br />Valley except at the Del Norts gage. Heavy snows fell in the . higher alti-
<br />tudes during the middle of June, followed by a sharp rise in temperature.
<br />Then for five days rain fell over the area with another increase in tem-
<br />perature. At Monte Vista the five day volume from June 29 to July .3, was
<br />76,760 acre-feet. The river overflowed its banks to a width of one and
<br />one-half miles. The peak at the Del Norte gage was 15,000 cubic feet per
<br />second, and volume was 94,000 acre-feet fer the same five day periOd. At
<br />Alamosa the peak was 14,000 cubic feet per second, and the five day volume
<br />66,100 acre-feet. Although the peak was higher than any previously recorded
<br />at Alamosa, little overflow ~ccurred since dikes had been built and the
<br />channel improved 'in that area. Also, during the high water,the local
<br />populace exerted every effort to keep the water out of the city.
<br />
<br />In New Maxi co the Espanola Valley, which embraces the area
<br />adjacent to Espanola, New Mexico, and the Middle Valley, which extends
<br />from Cochiti to the bead of Elephant Butte Reservoir, are both subject to
<br />spring and fall floods.
<br />
<br />The Espanola Valley, with about 6,000 acres intensively culti-
<br />vated, is especially susceptible to floods since the valley is at the
<br />confluence of the Rio Chams and the Rio Grande.
<br />
<br />.(
<br />
<br />. ' .
<br />
<br />"
<br />I
<br />
<br />\,~?
<br />
<br />t
<br />l.
<br />!.:-...u
<br />
<br />,
<br />
<br />I The highest flows of record in the Middle Valley occurred in
<br />1920. On May 11, 1920, the mean daily flow at the otowi gaging station
<br />was 12,400 cubic feet per second. The river then receded Wltil May 18,
<br />and again began to rise to a mean daily peak of 28,000 cubic 1'eet per
<br />second, on May 23.
<br />
<br />The most disastrous flood of recent times to the Middle Valley
<br />occurred in 1941. Flows exceeded 22,000 C"'lbic feet per second at otowi
<br />on May 16. This flood was primarily caused by rains on heavy snow cover
<br />in the mountainous beadwaters of the Rio Cbama.
<br />
<br />Since much of the flood flow in the Middle Valley is caused by
<br />floods of the Rio Cbama and smaller tributaries below its mouth, reser-
<br />voirs built in Colorado could not control these 1'loods. However, with
<br />control on the Rio Chams and on the Rio Grande, in Colorado, the greatest
<br />historical flow of the Middle Valley could be materially reduced.
<br />
<br />PREVIOU'3 STUDIES
<br />
<br />Preliminary Studies
<br />
<br />. .'
<br />, ...,;,.. Pre J.1niil1{lry sttuUes, , wni~ ;were ~ife:. tb '.deteI'llline' the ef'feots, or-
<br />general conditions and to develop'sound operation criteria, are summarized
<br />as follows:
<br />
<br />Studies 1 through 5 were required to. accurately determine, or to
<br />permit making an accurate estimate of, various oriteria to be used in the
<br />final operation study. They were also necessary to determine the feasi-
<br />bility of multi-purpose use, the caPacities required, and the most desir-
<br />able plan of development~ The studies considered three reservoirs, Wagon
<br />","!" ('\
<br />r .-..;"# '-':.l \J
<br />.E-24 \,1. ,....,
<br />
|