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o (-, ~ I -, CQ ~q Change in spawning bar morphology will be determined by producing three-dimensional plots of the surveyed spawning bar and subtracting the calculated volume of the current plot from the volume determined in a prior survey. The amount of change (positive or negative) will be compared to the flow conditions for the year in question. The size distribution of cobble at each spawning bar will be measured and the D'6' D,o and D.. sizes (cobble diameter exceeded by 16%, 50% and 84% of the samples, respectively) computed and compared to previous years. Depth of open interstitial space will be computed as actual depth and multiples of mean cobble diameter. It is anticipated that spawning bars wilI change with time, to the point that the existing bars may no longer be suitable for spawning and that others will be used as they develop. A longitudinal survey of the river in 1994 located and characterized bars that contained loose cobble. Every 5 years, a similar survey will be completed between RM 180 and RM 116 to locate newly-formed bars that may be suitable for Colorado pikeminnow spawning. Data will be summarized and reported annually. Data included in the report will include topographic survey plots showing bar surface and depth of open interstitial space, change in bar volume from the previous year, mean and ma.ximum depth of open interstitial space and particle size distribution. Response to flows and long-term trends will be analyzed and reported every 5 years. BackwaterlLow Velocitv Habitat Phvsical Measurements To characterize the relative quality of backwaters, five representative backwaters within each geomorphic reach will be measured for water and sediment depth. Sampling will occur annually between September 15 and November 1 during habitat mapping. These sites will remain the same from year-to-year to the extent possible. If a backwater is "lost," another will be selected for sampling and retained in the sampling regime until it is lost. Depth of sediment will be measured and recorded for "lost" backwaters. All measurements will be made at flows between 500 and 1,000 cfs, and at the same flow from year-to-year, if possible. Sediment and water depths will be measured at three points in each backwater (mouth, 113 and 2/3 oflength). The backwaters sampled will be marked on digital aerial imagery. Storm events will be determined by changes in flow and turbidity at USGS gages located near Shiprock and Montezuma Creek. The need to continue this element will be assessed after 5 years. Annual reports will include a summary of backwater measurement data for each site, including site location, water and sediment depth, flow at sampling, flow and turbidity data. Every five years the runoffi'storm event/backwater habitat relationships will be analyzed. II Draft Long Term Monitoring Plan - SJRIP Biology Committee