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UARB on bi-weekly to monthly intervals. At 2 or 3 times annually, grab samples also will be <br />taken at these locations for analysis of TDS, specific salt ions, Se and U concentrations using <br />CWQCD-approved protocols. An effort will be made to coordinate with the UAWCD to <br />position sampling locations near anticipated new stream gauging locations in Cottonwood Creek, <br />the South Arkansas River, and other sites. Samples will also be taken near the CDWR gauges on <br />Cottonwood Creek near Buena Vista and on the South Arkansas River near Salida. To <br />supplement this data, we also plan to measure only water quality at the upstream ends of 3 to 5 <br />canals in this region. Simultaneous flow rates in the canals will be obtained from CDWR <br />diversion records. Final stra#egies to monitor flows and water quality will be determined in <br />consultation with the partnering agencies and organizations. At sampling locations distant from <br />existing gauge sites or when gauges are not operational during the winter (yet ice cover does not <br />prohibit measurement), simultaneous streamflow measurements will be made using ADVs or <br />ADCPs. Simultaneous stream flow measurements also will be made 3 to 6 times per year at <br />sampling sites near existing stream gauges to check the accuracy of flow rating equations at <br />those gauges. <br />Task 5: Measurement of Canal Seepage <br />Inflow-outflow tests, under partial support from this project, will continue to be conducted along <br />seiected segments of major canals within the LARB study regions to estimate rates of seepage <br />loss to the surrounding shallow aquifer. Similar measurements will be made on selected canals <br />within the new UARB study region. <br />Task 5a: Identification of Canal Reaches for Seepage Tests <br />About 1 or 2 seepage tests will be conducted in up to a total of about 5 to 10 reaches within a <br />total of 3 to 5 canals in the LARB. Selected reaches will include those in which seepage tests <br />have been conducted by CSU and others over the last seven years to obtain additional <br />information about temporal variability in seepage rates. New reaches will be selected in <br />consultation with ditch company personnel to be representative of field conditions (e.g. typical <br />size and shape of cross section, nature and density of vegetative cover, water table conditions on <br />the canal boundaries, etc.) and to fit within the operational constraints and interests of the ditch <br />companies. An effort also will be made to coordinate site selection with the USGS and the <br />UAWCD which plan to install thermistors in piezometers along selected canals to make <br />localized measurements of seepage rates. About 1 or 2 seepage tests will be conducted in a total <br />of about 5 to 10 reaches within a total of 3 to 5 canals in the UARB. These reaches also will be <br />selected to be representative of variable field conditions and to comply with the interests and <br />constraints of the ditch companies and with those of the USGS/UAWCD study. <br />Test 5b: Conduct of Seepage Tests <br />Simultaneous measurements of flow velocity and stage will be made at canal cross sections <br />bounding the upstream and downstream ends of each selected canal reach (using ADVs or <br />9