ISCO automated water samplers are programmed to collect a daily composite sample (4 samples per day [Midnight, 6AM, noon, and 6PM] collected into one bottle). Samples are picked up from the field sites every 21 to 24 days and transported to the lab.
Around October 1, the bedload boxes are cleaned out and the volume of material removed is measured in a bucket of known volume. The stream is diverted around the bedload box using a large PVC pipe diversion and the water in the bedload box is pumped out. The material in the bedload box is shoveled into a bucket and the number of buckets removed is recorded (wet volume).
Total Suspended Solids (TSS): A Millipore type AP40 glass fiber filter (47mm) is dried at 103 degrees C and weighed. A subsample is filtered and the filter with sediment is dried (103 degrees C) and weighed following Standard Methods for the Examination of Water and Wastewater #2540 D.
Turbidity: Samples are measured using a turbidemeter with a flow through cell.
Conductivity: Samples are measured using a conductivity meter once samples have warmed to room temperature.
Total Dissolved Solids (TDS): Prior to 5/7/1998, TDS was estimated as 50 percent of conductivity. After 5/7/1998, a TDS estimate is calculated with a function on the conductivity meter. “Orion conductivity systems report a sample’s TDS value in mg/L of sodium chloride by comparing its conductivity and temperature to data stored in the meter’s memory. Data was obtained from the International Critical Tables” (Orion model 150 conductivity meter manual).
To determine a conversion factor from wet volume to dry weight, subsamples were collected and brought to the lab in 2002 and 2004. Wet volume and weight of the subsamples was measured, the samples were dried in an oven at 55 degrees C for at least 4 days or until no weight difference was recorded on subsequent weighings. Dry volume and weight of the subsamples was recorded. A weighted average of dry weight to wet volume was calculated to use as the conversion factor.
