Laserfiche WebLink
<br />1;k-: ~..; -. ';j ,'~...;.::;:.;.-s<r{~~<<;w.~/.,,_,^,,_---;;;,>41''--' - ,",'-- ,.. .', <br /> <br /> <br />t <br />", <br />r <br /> <br />;1 <br />, <br />';~ <br />i1 <br /> <br />.~ <br /> <br />,-~ <br />'.-:~ <br />_.~] <br /> <br />",' <br />~~ <br /> <br />;-;; <br /> <br />o <br />, '-; <br />'<::l" <br />('J <br /> <br />drains, thus disturbing the hydrologic balance of the practice of <br />subirrigation in the Valley". Deepening of portions of the river <br />channels should became rrore practical as subirrigated areas decrease. <br />Otherwise, the deepening of the river and its tributaries would not <br />be practical, and the present riverbed elevations should be retained. <br />Land for which adequate drainage cannot be provided by gravity <br />drainage could be drained on a smaller area basis with a system <br />of drains and purrps. (See Study Item 5 relating to drainage <br />systems. ) <br /> <br />(.:::.... <br /> <br />...... <br />_,.1 <br /> <br />-L_STUDY ITEM 10 - ESTIMATE ACREAGE OF pHREATQPHYTES THAT NEED CXlNTOOL <br />, (Refer to Map-ll, Phreatophyte Map). <br /> <br />This study item has been divided into three parts: cottonwood, <br />greasewood, rabbitbrush, and other phreatophytes. Financial or <br />technical assistance will be limited by the Department of Agri- <br />culture I s restrictions a=rding to wetland types rrentioned under <br />Study Item 5. <br /> <br />CQ'I'I'()N\'lX)D <br /> <br />The cottonwood (largely narrow-leaf cottonwood, Populus Angustifolia) <br />trees along the Rio Grande River are a resource or a liability <br />depending upon their use and rnanagerrent. To water users they may <br />represent a liability since they do use substantial arrounts of <br />potential irrigation water. On the other hand they represent a <br />resource useful for providing raw materials for industry and jcbs. <br />The cottonwood areas present a rolorful, pleasing, aesthetic appear- <br />ance to an otherwise open rountryside, a source of food and rover <br />for wildlife valuable to the San Luis Valley, sare pasture, and a <br />lot of winter protection for doIrestic livestock. In addition, the <br />trees provide protection from -silt pollution through stabilizing <br />and protecting strearrbanks. Many groves of trees have a high <br />recreation potential. <br /> <br />Before any decisions as to the use and rnanagerrent of this cottonwood <br />area can be made, sane priori ties should be established regarding <br />the total needs of the area for the alternative uses that are present. <br />Also, the ecology of the cottonwood type should be rrore thoroughly <br />understood before making decisions that rould becare irreversible. <br /> <br />As nearly as can be estimated, there are about 25,000 acres of <br />cottonwood in the San Luis Valley. (This figure is taken fran <br />pages 416-417 of a Regional Planning Report of the Upper Rio Grande, <br />dated Februcu:y 1938, by the National Resources comnittee. 11 <br /> <br />11 See reference 15 <br /> <br />16 <br /> <br />