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At each of fl1e test locations, CDM obtained access from t11e landowner or managing <br />agency prior to the start of the field activities. The 30 locations were selected to <br />represent the range of stream channel conditions (width, depth, braiding, etc.) present <br />on t11e Sout11 Platte River and selected tributaries (Cherry Creek, Plum Creek, Sand <br />Creek, Lone Tree Creek, Caclle la Poudre River, Box Elder Creek, West Bijou Creek <br />and Beebe Draw). During original Task 34 scoping, five test site locations were <br />chosen adjacent to the existing State Engineer's Office (SEO)/United State Geological <br />Survey (USGS) gaging station locations along the South Platte River (Henderson, <br />Kersey, Weldona, Balzac, and Julesburg). The availability of continuous stream stage <br />data records from fllese locations, coupled with t11e presence of cont>1luously- <br />monitored piezometers >IZStalled adjacent to t11e gages during P11ase 2, Task 35, is <br />intended to allow evaluation of the stream stage relative to the groundwater level <br />elevation, and to evaluate the aquifer's response to changes in stream stage. <br />However, at the Weldona Gage, a piezometer could not be installed during Phase 2, <br />Task 35 due to the presence of shale bedrock above the water table. Dur>11g Task 34 <br />site access activities, test locations were also sited at the Fort Morgan Gage and the <br />recently installed Atwood Gage. All stream gaging locations are shown u1 Figure 2. <br />Each of fl1e study locations is identified with a streambed conductance location <br />number beginning with an "SC' for stream conductance, followed by a number from <br />1 to 30. Sites were generally numbered beginning with the westernmost site location, <br />then generally moving downstream through site number SG301ocated near the state <br />line at Julesburg. Due to site access constra>11ts and site conditions observed during <br />reconnaissance, several test sites were relocated after numbers had been assigned, <br />resulting in several sites being out of sequence in the numbering system. <br />Sediment coreholes and the resulting lithologic and geotechnical samples are named <br />using the test site identification, followed by a letter denot>lzg the relative stream <br />depth (Shallow, Intermediate, or Deep) from which the sample was collected at a <br />transect, followed by the depth interval below the channel bottom from which the <br />sample was collected. As an example, sample SG03-S-1.5-2.3 was collected at test site <br />SC-03 at t11e shallow water depth core location, from t11e 1.5 feet (ft) to 2.3 ft core <br />depth interval. <br />2.0 Field Data Collection Procedures <br />Tl1is section describes field activities and methods implemented under Task 34. All <br />testing was performed in accordance with published methods (ASTM 1998, ASTM <br />2002, Cardenas and Zlotllik 2003, Bouwer and Rice 1976). All activities were <br />completed according to a CDM approved health and safety plan prepared for fl1e <br />Task 34 Field Program. <br />All sampling, testing, and stream channel survey locations were referenced relative to <br />either a temporary benchmark or an exist>11g stream gage station benchmark. <br />Prior to beginning the Task 34 activities, it was anticipated that data from a USGS <br />stream gain/loss investigation from Denver to Fort Lupton (McMahon et al. 1995) <br />would be incorporated alto this effort. However, review of these data indicates they <br />Fnlal T~zsl: 3~TM 06-28-07.doc <br />