Chloride Concentrations

Woodland Pond shows the greatest fluctuation in its chloride ion concentrations as well its conductivities. In early June you see in this chart that its ion concentration has increased.  The amount of rainfall was relatively low up to that point and
the lowered flow of Diversion Creek is putting in less water and salt.  Increasing loss of water by evaporation from the pond concentrates its salt content. The good rain following dilutes the salt content of the pond.  Higher rainfall puts in more water than the creek puts in.  By the middle of June warmer temps increase the evaporation rate in the pond. Then the following rain immediately lowers the salt concentration again for awhile.

The high chloride content in Woodland Pond may account for the following  biological phenomena.

In 2009 & 2010, the cattails in Woodland Pond were very late in developing new stems and leaves, whereas the cattails in Hartley Pond were well-developed at the same time. That spring saw very high salt levels in Woodland Pond during the same time.

Spring Wood Frog mating calls seem unaffected by the water pollution in Woodland Pond. They are done with that activity in a week or two, before the pond conductivities rise to much higher levels. Spring precipitation directly into the pond dilutes the salt ion content of the pond at those times. We have no information on the following presence of frog tadpoles in the pond when the ion content is much higher.

Red-winged Blackbirds in the spring of 2009 & 2010 looked unhealthy and they disappeared early from Woodland Pond, while the healthy looking ones in Hartley Pond continued well into the summer.