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• 2. SUMMARY OF 1997/1998 FIELD DATA COLLECTION EFFORT Floodplain habitat restoration investigation activities began in the Spring of 1995 at six of the Green River bottomland sites located in the Ouray National Wildlife Refuge (ONWR), near Ouray, Utah. Thirty-six river cross sections were established and surveyed in the ONWR to create a hydraulic model to identify typical bankfull discharges and flooding discharges for the bottomland sites in the refuge. Since that time similar studies have been conducted at specific bottomland sites all along the Green River from Split Mountain to Pariette Draw. Twenty additional river cross sections were established in 1996 at five bottomland sites upstream of the Ouray National Wildlife Refuge. These sites are referred to as the BLM bottomland sites. Several other river cross sections have been established in the aforementioned reach, however, this discussion is limited to the ONWR and BLM sites where floodplain restoration activities have been implemented. These cross section surveys have been used as a tool to identify the channel morphology of the specific reaches and to develop stage discharge relationships to accurately predict the flooding discharges at each site. During 1997, all twenty of the BLM river cross sections and five of the ONWR river cross sections, near the Johnson and Old Charlie Diked bottomlands, were re-surveyed. During the 1998 runoff season, the twenty BLM cross sections were again re-surveyed and a total of nine cross sections near the Johnson, Leota, and Old Charlie Diked in the ONWR were re-surveyed. The results of these cross section surveys are tabulated in Chapter III of this report, and the data and actual cross section plots are presented in the accompanying technical report. In addition to the river cross section surveys, several sets of stage measurements have also been taken in the BLM and ONWR reaches during the 1997 and 1998 runoff seasons. These data improve the accuracy of stage predictions for each bottomland site and help to quantify any shifts in the stage discharge relationships in the river adjacent to the bottomland sites. These results are presented in the accompanying technical report. To quantify erosion and sedimentation at the levee openings, and in the bottomlands themselves, monitoring cross sections with permanent monuments were established at each site. Corresponding mapping showing the locations can be found in Chapter III. The following summarizes how many cross sections were established at each site: Bonanza Bridge -The Bonanza Bridge bottomland provided the greatest opportunity for extensive erosion and sedimentation monitoring due to ease of access and the configuration of the site. Four cross sections have been established across the inlet and bottomland itself at varying distances from the opening. In addition, topographic mapping of the inlet area and adjacent sandbar conducted after both the 1997 and 1998 runoff seasons has provided a greater understanding of the erosion and sedimentation processes. Results are presented in chapter III. Horseshoe Bend - At the Horseshoe Bend bottomland, one cross section has been established across the length of the 1000' levee removal and two cross sections have been extended across the bottomland. One year of results are presented in chapter III. Stirrup -The Stirrup bottomland has one narrow channel connecting the site to the river from the downstream end. The monitoring of the inlet channel has been limited to the topographic mapping of the channel. However, three additional cross sections have been extended across the bottomland on line with the river cross sections ST-1, ST-2 and ST-3. 2-1