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2018 Cumulative volume changes between the dam and Ranges I through 4 show low magnitude oscillations of approximately +150 acre feet to -600 acre feet, with positive values indicating aggradation and negative degradation. Between the darn and ranges 5 through 7, the cumulative net volume changes are ahnost all negative to a maximum of approximately 1,300 acre feet, though values generated from the 1972 survey indicate aggradation. Between the darn and Ranges 8 through 13, there is degradation or slight aggradation ("-800 acre feet to + ISO acre feet) through the 1962 survey, then significant (" II,OOO acre feet maximum) net aggradation for the subsequent surveys. This substantial change occurs after a large magnitude flood in 1965. It should be noted that the data sets are not complete. Not all of the Degradation Ranges were measured during all of the surveys. Figures 40 through 78 show the area and volume calculation results graphically. Tentative conclusions drawn from this infonnation are that a limited amount of scour and a significant amount of deposition have occurred downstream of John Martin Dam since it began controlling flows. A state of non-equilibrium appears ~o exist, at least within the reach covered by the Degradation Ranges. Further study will be needed to determine the specific causes of impacts. / 2 Table 1. Linear Correlation (R') Values Location Arkansas River at Las Purgatoire River at Las Arkansas River below Time Period Animas, CO Animas, CO John Martin Dam, CO January 0.85 0.77 0.72 February 0.86 0.79 0.52 March 0.92 0.80 0.78 April 0.75 0.82 0.34 May 0.88 0.82 0.05 June 0.90 0.88 0.02 July 0.77 0.78 0.05 August 0.81 0.84 0.01 September 0.65 0.90 0.00 October 0.90 0.89 0.18 November 0.94 0.77 0.55 December 0.95 077 0.61 Aggregate 0.85 0.86 0.69