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Animas River at Durango The peak seasonal/HCI relationships in this basin appear to behave in a manner very similar to that of the San Juan River at Pagosa Springs. The physical orientation of the basin is similar to the Animas and thus, there the similarities are not overwhelmingly surprising. The reader is directed to the prior section for the San Juan River for details. Dolores at Rico This river produces a much lower amount of natural runoff than the San Juan and Animas Rivers however; users in this basin rely on surface water in this location as well. Unfortunately, it appears that there is no real notable relationship with the naturalized flow and the HCI values, if anything it is far less notable than the neighboring basins. A potential explanation is that the basin is oriented more north-south than the San Juan/Animas basins therefore the influx of moisture into the region from a south/southwesterly direction is far less orthogonal than earlier thought. Table 6. Summary of Apr.-Sep. Naturalized Streamflow/HCI Relationships for the San Juan/Dolores (‘X’ indicates a relatively strong relationship and ’O’ indicates a relatively weak relationship). PDOMEISOINino 3.4 NAOAMO District 30 X OO District 32 XXX District 34 XXX District 71 OOX F - Single Seasonal Runoff Timing The timing aspect of the runoff in the basin was examined by looking at the comparison of the Julian Date of the 50% point of the April-July peak seasonal flow verses the HCI values. Before this was performed (period of available record 1975- 2003), it was necessary to determine the relationship of the date of 50% flow and the actual volume of that year. In the case of the flow of the Animas River at Durango, the overall relationship between 50% flow and the volume was significant enough that we examined the residual (or in effect taking out the effects of volume) to determine the seasonal melting effect. The net result in looking at this variable was that El Nino years did have a tendency to have a delayed runoff in the basin (at least from reaching the 50% of total flow while La Nina years were earlier). It is unsure what impact temperatures may have on this tendency or if it relates to some extent, to the tendency of more precipitation in the spring with El Nino, delaying the runoff. 25