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" -I .) · fJG1J~7 accomplished by using data from the NWS It Gunnison .nd Oelt.. The only data available It these station Is temperature and pre<:lpit.tlon data. Meteorologl<:al data from the WTHR Itation at Steamboat Springs was also used In a portion of the Invastlgation. The first portion of the analysis Involved comparison of the available weether dat.. The atta<:hed Table 4 presents approximate growing leasonl average monthly temperature. and precipitation for the Colorado and Bear RIver Itatlons. With the exception of the previously noted trend In maximum temperatures. review of the temperature data found no other unusual trends between the Colorado and Bear River NWS. It II noteworthy that temperatures st Delta are slgnlfl<:antly higher than at the Bear River or other Colorado stations. Comparison of relative humidity. wind. and solar radiation were also made comparing the Montpelier, Randolph, and Hilliard electronic stations to the Steamboat Springs WTHR station. The WTHR data was provide by Dr. Luis Garcia of IDS-CSU. It Is used with caution beClluse in . report entitled. REFERENCE EVAPOTRANSPIRATION MAPS FOR COLORADO. that Dr. Garcia co- authored. It was stated that thara were many errors in the data Ind only 45% of the WTHR station-month data Wall validated for use In that report. Average monthly values of relative humiditY. wind and solar radiation for the Bear River statlona and the Colorado station are ahown In Table 2. Also shown In Table 2 are comparlsonl of the Bear River Itations to Steamboat Springs. Minimum relative humiditY Is higher at Montpelier than at Randolph and Hilliard .nd this difference can probably be attributable to the lakes which are located a few miles to the south. Differences In relative humidity between Randolph and Hilliard and Steamboat Springs are not significant. Additionally. differences In solar radiation are also not significant. There are large differences in total wind between each of the Bear River sites. Comparison between Steamboat Springs and the Bear River sites found that the wind at Steamboat Springs and Montpelier is similar; whereas wind at Randolph is 28 to 45% higher. and wind at Hilliard Is 87 to 111 % higher. This may not be significant because HIli reports that in his calculation of Etr he uses a 100 miles- . per-day upper limit. Therefore. the large differences in wind may not have that great of an Impact. Discussion of the Lifton NWS Is warranted. The station I. foclted on an earthen embankment that separates Bear lake from Mud Lake. Bear Lake Is .n open water surflce. deep lake and Mud lake is a open water. cattall-bullrush awamp and wetlands wildlife refuge. In the Immediate vicinity of the welther station Ia . large gravel parking lot. The surrounding wlter bodies may suppress the meximum temperature and Incresse minimum temperatures during the growing season. Therefore. the SCS-BC coefficients determined using the Lifton NWS site and Montpelier electronic weather Itatlon are very localized. 'yi1 )'<'~'}' The growing season in the Montpelier-Randolph-Hilliard portion of the Beer River basin is generally from early May to mid October. The growing season at the four Colorado stations WBl estimated using the criteria of a mean daily temperature of 45 degrees Fahrenheit to estImate the start and 2B degrees Fahrenheit to estimate the end. The average dates for the beginning and end of the growing season are summarized In Table 2. 13sa.I\MEMO _ - '.21.11 I A .10 WALTER vO'd ,00'oN 6v:~1 56 5, 6nt;j ,OB,-19L-~O~-1:131 Josst;j ~ Jalaa~~ .~.~