In 2017, JSWCD developed our Antelope Creek water quality monitoring program to track water quality parameters before, during, and after the implementation of the Hopkins Canal Piping and Bradshaw Drop Irrigation Conversion Projects.
Antelope Creek receives irrigation return flows from the project area and is a tributary to Little Butte Creek, a highly important tributary to the Rogue River for both drinking water and salmon and steelhead habitat; both waterbodies are water quality limited for a variety of factors including sedimentation, bacteria and temperature.
There are four monitoring locations for this project: one in Yankee Creek and three in Antelope Creek (sites upstream and downstream of Yankee Creek and at the mouth of Antelope Creek).
Overall, we have seen significant changes in two of our water quality parameters since the start of monitoring and the inital projects' completion: there has been a reduction in E. coli and total phosphorus concentrations at all of our four monitoring sites.
We are excited to see that there has been a 71% reduction in E. coli concentrations and 27% reduction in total phosphorus concentrations at one of our monitoring sites, the one closest to the project implementation area and most likely to reflect changes directly related to these projects.
This same site has also experienced a significant decrease in flow during the irrigation season. This can likely be attributed to the large number of acres that switched from flood irrigation to drip irrigation as part of the Bradshaw Drop CIS. This conversion led to more efficient water use, which means less flood irrigation run-off flowing back into Antelope Creek. While there is now less flow instream in Antelope Creek during the irrigation season, there is also less pollutant inputs to stream waters, including E. coli and phosphorous, and improved water quality.
We will continue our monitoring efforts here for the next several years to further our understanding of how canal piping and irrigation conversion projects such as these, in addition to other projects that continue in the area, impact water quality.