Research Protocol for Cottonwood Ranch (2)

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Transects across the middle channel, modified by riparian vegetation clearing, will be surveyed at low flow following the Cottonwood Ranch research protocol outlined below. Low flows are needed to provide easier working conditions and for safety. Specific streamflow discharges at the Platte River at Overton, NE, gage will be identified for working at the downstream cross sections after these sections have been established. The cross-sectional transects were established within and downstream of the Cottonwood Ranch Property as part of the General Monitoring Protocol. General Monitoring transects to be surveyed include three research cross sections that are coincident with general monitoring locations and five cross sections downstream of Cottonwood Ranch and upstream of the Kearney Canal Diversion. These initial General Monitoring cross sections are shown in Figure 1. The channel variables for these eight General Monitoring cross sections will be collected through the research project. The Platte River General Monitoring Program will maintain data collection at some or all of these cross sections after the completion of this research project. The data collection in year 2000 will serve as the pilot year for purposes of refining the Platte River General Monitoring Protocol. Data collected at these initial General Monitoring cross sections will: 1) Provide first year data for long term monitoring, 2) refine costs for collecting data at these widely spaced monitoring cross sections, and 3) identify statistical characteristics of variables including variance and dependence estimates and the sensitivity of trend detection. Data collected at each transect will include topographic survey, bed sediment sampling, and ground photography. Data Analysis Data will be summarized at the transect level and statistics such as the mean and standard deviation will be compiled using transects as the sample size. These data will be included in an annual data report. Post-stratification of the transects into managed, urunanaged, and downstream strata will enable analyses of the data for each strata. Trend detection will involve computing the least squares regression line through all the data points in a regression of any summary measure against year. Statistically significant increases or decreases in trend will be defined as a nonzero regression line. Research Protocol Data Collection Transect types are outlined in Table 1 and locations of these transects are shown in Figure 1. There are two types of transects identified: 1) Temporal intensive cross sections that are surveyed four to six times a year (including before and after high flow season and a survey in the Fall) along with ancillary data (i.e. bed and bank material sampling and ground photography), and provide information on intra-annual variability; and 2) spatial intensive cross sections that are surveyed and the ancillary data collected once a year on a series of tightly spaced cross section to provide information on changes within specific channel reaches. The spatially