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The cross - valley transect extended an additional 3.4 miles beyond the study site to the <br />south, and 2.5 miles north of the northern most river channel (Figure 6). The transect wells <br />were installed by the U.S. Bureau of Reclamation, and were constructed of 11 /a inch schedule <br />40 PVC pipe. The wells ranged from 20 to 50 ft deep, and had the lower 5 feet perforated. <br />The river stage gaging station was near the northwestern corner of the study site on a <br />very small channel of the Platte River. Surface water from the Platte River entered this <br />channel only at high flows. At lower flows the channel was fed primarily by a groundwater <br />drainage canal that entered the channel near its inlet, about 1.3 miles west of the study site <br />(Figure 6). Staff gages were also established within the study site at the east end of this small <br />channel, and at the east and west ends of the groundwater drain. These staff gages helped <br />determine the surface water elevations surrounding the site. The Gully Staff was installed in <br />an old, dry channel, but surface water was seldom observed in this channel. <br />Rowe Sanctuga Site <br />The second study site (Figure 4) was at the Lillian Annette Rowe Sanctuary, <br />approximately 10 miles north of Minden, Nebraska. The Sanctuary is owned and managed by <br />the National Audubon Society for the protection of wildlife and native plant species. The site <br />was composed primarily of seasonally flooded native prairie, and was located on the south side <br />of a large island between two channels of the Platte River. Controlled burning and haying <br />were used to manage the Sanctuary. <br />The well grid had 19 observation wells. The three side wells (RS8DCA SW, <br />RS8CDC -SW and RS 17BBC -SW), and the four Rowe West and East wells were installed for <br />a study by the National Audubon Society. These data were also used for our grid analysis, <br />although the continuously recorded data were not used. All wells were drilled to a depth of <br />10 feet with a Giddings Rig, except the two Rowe West and two Rowe East wells which were <br />installed by the National Audubon Society by pounding an open- ended, non - perforated 20 ft <br />pipe approximately 16 ft into the ground. The cross - valley transect wells (Figure 7), including <br />the northeastern well of the grid, were installed by the U.S. Bureau of Reclamation. Transect <br />12 <br />