|
<br />
<br />f1ood~ of about .equal magnitude will cause flooding in each section ?f
<br />the nvcr, m Tnmdad, above, and also below the City, The losses III
<br />the agricultural arcas of the flood plain result principally from damage
<br />to crops, farm improvements, roads, and bridges. Losses also .in7
<br />clude the depos.ition of ~and, gravel, and. debris ,!n cultivated I~nd.
<br />Except for the mterruptlOn of through rail and highway traffic m 'a
<br />nOrthellSt,southwest direction, flooding in the agricultural areas be-'
<br />tween Long Canyon and Alfalfa causes little intangible loss. '
<br />50. Flood damages, caving banks.-Caving banks have been an item
<br />of loss along Purgatoire Jtiver. The velocity and turbulence of the
<br />water in the stream cause a large amount of caving even when high,
<br />stages do not prevail. As the greater part of sloughing along a caving
<br />bank occurs at Icss than bankfull stages, a ll11'ge portion of these losses
<br />would be nonpreventable, except by constructing' bank-protection
<br />works.
<br />51. Flood damages, irrigation.-Damage to the i1'1'igation structures
<br />is dcpendent not only on the peak discharge, but also on relative
<br />volume of run'off for a given discharge. Large volume floods with
<br />susta.ined recession flows result in larger damages than small volume
<br />floods of comparable pcuk discharge. A comparison of damages dur,
<br />ing the flood of July 1925, one of small volume, which amounted to
<br />$17,000, and those of April 1942, a, large volume flood, which were
<br />$90,000, for, respective peak discharges of 33,000 and 35,800 cubic
<br />feet pel' second at, Trinidad, indicates that peak discharge only is
<br />not a measure of damli~es. The destruction 01' damage of small tem-
<br />porary headworks, whICh arc used to divert wutcr into irrigation
<br />ditches, is not considered hcrein as a flood damage. Since such
<br />damage nOlmally is to be anticipated, it is more properly classified
<br />as a maintenance cost to the irrigation project. These structures
<br />are damaged or destroyed by small flows; and such damage or de-
<br />struction may occur several times during a single year.
<br />52. Existing projects.-There has beon no project authorized by
<br />Congress for flood control, navigation, 01' other stream improvements
<br />on Purgatoire River or its tributaries tobeeonstructed by the War
<br />Department. "
<br />53. Improlwmp,nts, Trinidad.-Subsequent to thc dcstruetiveflood
<br />of September 30, 1904, the city of Trinidad and the Atchison, Topeka
<br />& Santa Fe Railway Co. cooperated in straightening the channel
<br />and constructing reinforced bank protcction walls at certain critical
<br />localitics in thc city, Thcse improvements are rcportcd to have
<br />cost about $62,000. The Works Progress Administration completed
<br />a bunk rrotection project in Trinidad during 1936. This work con-
<br />sisted 0' approximately 430 linear feet of rock,filled crib dikes. The
<br />total cost of th.e project was $6,930, of which $4,068 werc Federal
<br />funds. Approxl1nately 250 feet of wall wcre washed out by the flood
<br />of July 17, 1938. 'I'his break has been repaired by the Works Prog,
<br />ress Administration by driving wood piles and attiwhing heavy wire,
<br />behind which rock was dumped. The total eost of the work Was
<br />,$3,000, of which $2,000 were Federal funds. Repairs to bank pro-
<br />tection d'amaged during the April 1942 flood were estimated to have
<br />cost $10,800.
<br />54. Improvements, irrigation.- Irrigation projects along Purgatoire
<br />River have been described'in paragraphs 17 llJld 18 and relevl1I1t data
<br />are given in table No.3, Appendix C.'
<br />
<br />t NDt pl'i.nted.
<br />
<br />.
<br />
|