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' Johnson 4 1 J 1 1 This site is located at RM 261 on river left and was sampled during all three years. It is part of a series of four ONWR impoundments separated by man made dikes. When inundated, all of the dikes in the series are overtopped, effectively making the wetland size 136 acres (241 acres when full). The levee removal sampling only took place in the 19.8 acres (28 acres when full) of the J-4 bottom land. Prior to levee removal, flows in excess of 18,000 cfs were required to establish a connection with the wetland. An existing low spot in the Levee near the J-4 dike allows for water to flow through thick cattails and extensive plant debris into the site. A 200' wide, 3' deep breach was cut in the downstream end of the levee in March 1998. Large amounts of vegetation and debris located directly behind the breach create a virtual fish barrier even though there was a substantial hydraulic connection with the river during high flows. Vegetation consists of tamarisk, cattail, and hardstem bulrush. J-4 is classified as a depression and is likely to overwinter fish in 1998, unless draining takes place to install planned outlet structures. Leota 7 The Leota 7 pond is located on river right at RM 258, and was only sampled in 1998. It is one of a series of 11 ONWR impoundments separated by dikes. Two levee cuts were made in March 1998: a 600' wide, 2.5' deep cut which extends 200' back to the wetland; and a 350' wide cut at the downstream end. Unlike most of the other sines, this wetland does not flood until flows exceed 15,000 cfs. The upstream breach remained very shallow and a deeper channel did not form within the large cut. Thick cattail and hardstem bulrushes form a barrier directly behind the levee breach so that no well defined fish passage into the wetland was created. The removed portion of the upstream levee acted only as an inlet during the 1998 season. As runoff subsided, the downstream breach was down cut by water flowing from the site. No adult fish were observed moving from the L7 site back into the river as was common at most of the other sites. At peak runoff, all of the existing dikes were overtopped flooding an area of 727.9 acres (1180 acres when full). The L7 site is classified as a depression and would overwinter fish in 1998 except the site will be drained to facilitate construction of an outlet structure and fish kettle. Leota 10 This wetland, located at RM 256 on river right, is a natural terrace, where no artificial removal of levees has taken place. It was sampled in 1996 and 1997. It would have been sampled in 1998, but flows were not high enough to inundate the site for an extended period. Water seeps through the L10 dike causing a small area south of the dike to retain water for most of the summer. During high flows (above 16,000 cfs), water floods into the wetland all along the perimeter of the site with the main portion of the flows coming in at the top over the L10 a .? drainage ditch. The site will also backfill through a narrow channel at the downstream end of the site until flows are high enough to fill the site from the upstream end. Vegetation consists of i. N' tamarisk. willows. cottonwoods. cockleburs and several shrub and grass species.