Monday 07.26.2010 ~ Friday 07.30.2010
NAWQA is a program that was initiated by the USGS. Since 1991 the goals of NAWQA have been to investigate and describe the most up to date water-quality conditions for the majority of Nebraska's water systems, how water-quality changes over time, and how human activity contributes to water quality. During my first week, I had the opportunity to process some NAQWA samples, but this week I was able to head out and get some samples from the field.
This particular field experience on Nebraska's Platter River was the most interesting to me, because I learned methods and used equipment that have not been altered since their invention. The hydrological technician that I worked with explained to me that because so few people do the work that he does, there has been no need to improve the technology. Changing the technology would be too expensive as well and the cost wouldn't be worth the return or training. The steps to the sampling that we did followed accordingly (more or less):
1. By using a cable and metal crane, a weight with a sample bottle is suspended over a bridge and then lowered down into the water.
2. Distance is recorded once the weight hits the water and then the sample is lowered to the river bottom so that a sample of the entire water column can be retrieved.
3. While the weight is being lowered, a clicking mechanism is counting the amount of time it takes for the weight to reach the river bottom from the water's surface. The values of time and distance allow for the calculation of velocity.
4. The sample is reeled back up to the top of the bridge and poured into a churn.
5. The collecting method is repeated across the bridge until the churn is just about full. A portion of the river water is separated on the spot and the rest is returned to the lab for sampling.
We repeated this process every 20 feet across the entire Platte bridge at Elkhorn and at Salt Creek.
The collection at Salt Creek however did not require a crane because we were able to wade in the creek and collect the water from the within the stream.
**See attachments below for pictures!