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Page 2 <br />March 19, 1999 <br />conductivity under this scenario ranges from 793-1076 umhos/cm. Although the August EC <br />estimate exceeds 1000 umhos/cm, an exception to this standard was granted for portions of <br />Twentymile Park based on site specific data (see CHIA, past findings, and Exhibit 42 of TCC <br />permit). Therefore, if this situation were to prevail this spring, downstream impacts would <br />appear to be slight or minimal. <br />However, a possible scenario is that Fish Creek flow at site 16 will return to more historic <br />conditions during irrigation period of 1-3 cfs. Given that assumption, EC values downstream of <br />site 115 were estimated using historic values at site 16 and recent data for site 115. Table C <br />indicates EC values ranging from 2249-3771 umhos/cm downstream of site 115, far exceeding <br />the suspect level of 2000 umhos/cm set for upper portions of the Trout Creek basin. <br />Even [hough it may be of limited practical use, an analysis under average conditions based on <br />data collected over [he entire period of monitoring produces the following result. <br />Site 16 flow - 12.29 cfs <br />Site 16 EC - 499 umhos/cm <br />Site 1 l5 flow - .3454 cfs <br />Site 1 I S EC - 3890 umhos/cm <br />Modeled downstream =_> Flow - 12.63 EC - 591 umhos/cm <br />Assuming average conditions at site 16 and 390 gpm flow at site 115 with a current EC of 7175 <br />produces the following result: <br />Modeled downstream =_> Flow - 13.16 cfs EC - 940 umhos/cm <br />In summary, waters which subimgate and/or flood irrigate portions of Fish Creek would be <br />materially damaged if Fish Creek flows return to more normal patterns upstream of site 1 15 <br />and/or site 1 I S discharge water does not return to historic EC levels. <br />I also have additional questions generated as a result of my review. <br />Meter readings reported are in question and should be evaluated for accuracy <br />TCC planned to recycle water from the SWD. Has this been attempted? Why was it <br />abandoned? <br />Eazly indications based on FAXed data show elevated EC readings in alluvial we11006- <br />AW-2 and at surface site 1002. Efforts to confirm these levated EC readings were <br />compromised by TCC's inability to provide data collected over the October 1998-Mazch <br />1999 period for these two monitoring locations. <br />Suggested plan to proceed: Discuss results internally and gather more detailed information from <br />