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<br />FIELD STATION ANALYSIS <br />Water Year 2005 <br />WMFKMHCO William Fork at mouth near Hamilton, CO <br />Equipment: Sutron SatLink2 high data rate data logger driven by an accubar and powered by a solar recharged 12- <br />volt battery housed in a 6-foot square shelter over a 4-foot culvert well (no longer in use). Outside <br />gage is a wire weight gage mounted on the upstream side of the bridge almost directly above the <br />orifice. <br />Hydrologic Conditions: The basin consists of moderate terrain near the gage station but originates in steep <br />mountainous terrain in the Flattops. In the vicinity of the gage station, the channel slope is moderate. <br />The bed material is composed of small rock, cobbles, and occasional large boulders. The primary use <br />of water upstream of the gage is irrigation. <br />Gage Height Record: Primary record is IS-minute data from the data logger. Continuous gage height records were <br />kept from April 27 through September 30, 2005. The record is complete and reliable except for the <br />following days: <br />July 15 through August 5 and September 2 through 26 due to clogging of orifice. <br />Datum Corrections: Site surveyed on May 3, 2005 to re-establish and install wire weight gage. Data logger <br />corrections were made either at the time of visit or upon development of record. Data logger <br />corrections ranged in value from -1.16 when the wire weight gage was established to 0.00. <br />Rating: The shelter is located upstream of the bridge on the left abutment. The orifice is located slightly <br />underneath the bridge at the left abutment. The stream approaches the gage from a moderate left bend <br />300-feet upstream; the reach is then fairly straight all the way downstream to the cobble riffle, low <br />water control 300 to 400 feet downstream of gage. The high water control is the bridge contraction. <br />Rating No. 7 created on February 9, 2006 was used from April 27 to September 30. The highest <br />measurement used to develop this rating was 1,196 cfs (measurement number 2). The lowest <br />measurement used to develop this rating was 27.0 cfs (measurement number 7). Flows above 2,392 <br />cfs (twice the highest reliable measurement) on this rating should be considered poor record. <br />Seven measurements (numbered 1 through 7) were taken in the gage height record period ranging in <br />discharge from 27.0 to 1,196 cfs. These measurements covered the range in discharge for the record <br />period except for higher daily flows May 17, May 20 through 25 and June 3 through 5; and lower daily <br />flows September 15 through 21 and September 26. <br />Discharge: Rating No. 7 was applied directly and all measurements were adjusted to this rating except for <br />numbers 5 and 7, which required no adjustment. The adjustments ranged from -2.8% to 4.7%. <br />A peak flow of 2,110 cfs occurred on May 22, 2005 at 6:00 a.m. at a gage height of 7.13 with a shift of <br />0.00. <br />• <br />