Community Clean Water Institute’s citizen water quality monitoring program received an unusually high nitrate reading at our Austin Creek 010 testing site on 9/18/09! Typically, our Austin Creek sites have well below .1 mg/l nitrate levels, and last friday our volunteer monitor brought back a sample from AUS010 (First Bridge, near confluence of Austin Creek and Russian River) where our lab analysis confirmed a .312 mg/l!
The other two sites we currently monitor on Austin Creek (AUS020 & AUS030, upstream from contaminated site) had nitrate readings that were slightly above what we normally see this time but nothing too alarming. This leads us to believe the nitrate pollution source is somewhere between AUS020 and AUS010.
We will keep you updated on any further findings regarding this concern.
Do you have ammonia and total nitrogen data from the same sample event? At this time of year I would exclude failed septic tanks and focus on human camping activities along the creek, fertilizer residuals from growers operations, or a dead animal in or near the creek. Camping activity or a dead animal should be somewhat apparent. Septic tank dumping is always a possibility in remote areas.