May 15, 2009
Water quality sensor use in the Santa Margarita river, and shown during a Malibu Water Quality Symposium
By Sarina Cassaro and Kelly Lion, NPS and SDSU Field Stations Program
On Thursday April 23, 2009, Sarina Cassaro and Kelly Lion were successful in completing a river walk down the Santa Margarita River using the mobile water quality system designed by HPWREN PI Hans-Werner Braun. The water quality sonde is a Troll 9500 equipped with pH, dissolved oxygen, temperature, pressure and conductivity sensors. The lightweight Asus EEE laptop computer is equipped with a small GPS unit and wireless card, all which fit conveniently in a backpack. One of us had the laptop and associated components, and the other had the Troll and 6 foot cable. At each sampling point we would take off our packs and attach the Troll to the computer, start the laptop and type the command, "water." The computer would then take 10 readings of all of the above mentioned data.
We initially thought that it would take us about 4 hours to walk the extent of the river from the confluence of Temecula and Murrieta Creeks to the Gorge river crossing. We estimated the distance at 2.5 miles and assumed we would have 30 sampling points; roughly one point every 405 feet. We used a hand held GPS unit to track the total distance of the trip, as well as the distance between each sampling point. As we got further into our trip, we thought our distance estimate may have been on the short side, so we began sampling about every 500 feet. This turned out to be a wise decision since the actual distance was closer to 4 miles.
In actuality it took us about seven hours to get to the Gorge River crossing, mostly due to the amount of bushwhacking and scrambling over rocks. We collected water quality data at 22 sampling points that Hans-Werner then uploaded and imprinted onto a Google Earth file. This gives a great aerial view of the test run, and one can click on any individual sampling point to display all of the data collected.
On Thursday, 30 April 2009, Sarina Cassaro and Kelly Lion attended a water quality symposium hosted by the City of Malibu, California. Susan Teel of the California Mediterranean Research Learning Center heard about the symposium, and suggested that we demonstrate the mobile water quality system developed by Hans-Werner Braun.
Our table outside of the symposium demonstrated the probe and the Asus EEE computer system, including the GPS and wireless receivers. We also had a slide show playing continuously, which demonstrated the Google Earth file and the data that can be viewed by clicking on any sampling location point.
Everyone who stopped by our display was impressed with the system. Most of the questions focused on additional parameters that could be measured, such as nitrates, chlorophyll and fecal coliform bacteria, rather than specific inquiries about the system itself. We spoke to the water quality professionals about how this unit was a prototype and could be modified for different research purposes.
One gentleman suggested that he would definitely make use of it if it was easily available to monitor Malibu Creek. Another, from the California Regional Water Control Board, suggested that this system could be useful with a current monitoring protocol in place to sample between the Salton Sea and the Mexican border. He suggested that we contact the Water Quality Control Board if we were interested in pursuing field applications of the system.