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<br />e 001628 e <br /> <br />'u(' ~ ~!~Ah.A- ~~ <br /> <br />~ ~ <br /> <br />n lmtm~'r ........ is oOloR "more water in the river is always <br />bett r" Four fa(~tors lead me to conclude we need to re-think such a strategy for the San <br />Ju , mcluding 1) the SJRlP findings to date regarding fish co~ and physical habitat <br />response, 2) the JHA/RV A results presented here for the San Julii: 3) the realization that <br />San Juan flows have been less altered than those in other UCRB streams where recovery, at <br />least for Colorado pikeminnow. appears to be progressing at a somewhat faster pace CU. S. <br />Fish and WildlW~ Servicfu'7..qp~); and 4) the continued shrinkage of the San Juan channel. <br />'fuased upon theE:';; factorS',-fdOiiOt suggest the flow recommendations be WI <br />~6hd~tum to the conditions of the post-Navajo perio4:lIlI.Fil.., I ~ut st we re-phrase <br />our strategy to, I"more water in the river at times is perhaps better, less water at qi1Cf..~es <br />may also be bettl~r, and greater variability is needed". For example, the positivettA values <br />for May, June, and all maximum flow parameters for the SJRJP period (Table 1) indicate <br />the~er is expe,dencing mid-range flows (i.e., -2500 to <8000 cfs) too frequently, which <br />likely is contrihuting to the continuing channel shrinkage and habitat simplification <br />processes. & !~~~uction in the freque c ch events would restore historic variability 11 <br />and could ~~fe additional sto or more uent, arg re eases om a~o. am to IYA. <br />better synchronile with Animas River peak flows. ]--ikewise, the high, negativeHA values v~ <br />for December and January median monthly flows and all ~~~~ (Table. ~ <br />I) indicate SJRlP flows are grossly inconsistent with ~re evelopm t . record, <br />with the lowest SJRIP monthly median ~ws and m~~~tf~~:" ~:her than ~pe.L.. . <br />RV A limit. Here again, the possibility may exist for ater augmeqY6ther ~ I "'- <br />periods of the Yl~ar while reducing hydrologic alteration and perhaps increasing habitat <br />quality during low flow periods. Similar opportunities exist for other IRA parameters to <br />restore hydrolo gic variability and enhance mimicry of the natural hydro graph. <br /> <br /> <br />. <br /> <br />0; <br /> <br /> <br /> <br />CONCLUSIONS AND RECOMMENDATIONS <br />~ ~~~ <br /> <br />The flow regqn~ San Juan River has been a1.tered~' g the past 11 years <br />from the preJievelopment condition and the SJRIP flow r ommendations have <br />thu~ar !lot achieved mimicry of the natural hydrograph. Under the SJRIP's adaptive <br />man~gement procedures, the flow recommendations should be carefully reviewed <br />and adjlJ.sted as necessary to 1) restore hydrologic variability by reducing the <br />frequem:y and duration of mid-range flows, 2) augment pe~ flows as opportunities <br />present 1:hemselves, and 3) reduce augmented base flows a.Drng portions of the year <br />to bette[ reflect pre-Navajo Dam conditions. <br /> <br />The rebtive stability of the fish community and the observed physical habitat <br />changes over the past 11 years provide little evidence of a positive response to the <br />current flow recommendations. While the flow recommendations are being <br /> <br />10 <br /> <br />E09-~ BlO/ElO.d 99v-1 <br /> <br />-WOJ~ WdlZ:lO ED-9D-l~O <br />