INTRODUCTION 



This paper summarizes recently completed studies on water use by several important 

 plant communities in the Intermountain Region. These studies were designed to inventory 

 water use and to evaluate the effects of several vegetation conversion and stand 

 manipulation practices on potential water yield. 



Data were collected from 219 moisture sampling locations representing 14 sites and 

 10 vegetation types. Soil moisture depletion and evapotranspiration data from some of 

 these sites have been or are in the process of being published elsewhere (see list of 

 references in table 1, page 7). However, data on six vegetation types from five of 

 the sites probably will not be reported in other publications. 



The format is designed to provide the administrator, the researcher, and the 

 student with soil moisture depletion and estimated evapotranspiration data taken from 

 a wide variety of vegetation types, soils, and elevations. Obviously, all sites and 

 vegetation types have not been studied in this short period. A summary of these data 

 in a single publication may prevent unnecessary duplication of this work by others and 

 point up gaps in our knowledge of water consumption. 



SITE DESCRIPTIONS 



All study sites are within three general areas of Utah (fig. 1). Sites 1, 2, and 

 3 are in northern Utah within the Logan River drainage (upper right) . Sites 4 through 

 8 are in north-central Utah on the Davis County Experimental Watershed northeast of 

 Bountiful (lower right). Sites 9 through 14 are in central Utah on the Great Basin 

 experimental area east of Ephraim (lower left) . 



Each study was planned and conducted independently; consequently, supplementary 

 soil and vegetation descriptions are not uniform. Brief site descriptions are presented 

 in table 1; more detailed considerations of the soils and vegetation for most sites are 

 available in the literature citations (last column) . Their location within the site is 

 referenced by plot designations, such as 5a, 5b, 5c (tables 1 and 2, pages 7 and 10, 

 respectively). Natural understory vegetation on all sites was maintained throughout 

 each study; vegetation-type designations indicate only the overstory or dominant species. 



METHODS AND RESULTS 



Studies were to determine comparative water losses from two or more vegetation 

 covers on paired or adjacent plots (e.g., mature versus clearcut aspen or aspen versus 

 grass) . Soil moisture on the study plots was measured several times each season with 

 neutron moisture probes. All measurements on the Davis County Experimental Watershed 

 (sites 4 through 8, tables 1 and 2) were made with a Nuclear Chicago probe; all others 

 were made with a Troxler probe. 1 Measurements were taken in the top 6 inches and at 

 1-foot intervals thereafter to the bottom of each hole. 



The number of holes drilled at each site and their depths are presented in table 2. 

 Most were drilled by a hand-held pneumatic jackhammer, except those on sites 7 and 8, 

 where a track-mounted pneumatic drill was used. The latter method results in more . 

 uniform soil moisture access holes and more accurate readings. 2 



^rade names are used for identification only; they do not imply endorsement by 

 USDA Forest Service. 



^Richardson, B. Z. Installation of soil moisture access tubes in rocky soils. 

 J. Soil and Water Conserv. 21(4): 143-145. 1966. 



