Delaware Center for the Inland Bays

Over the summer, the Center celebrated the release of the Dirickson Creek Report at an event held at Mulberry Landing on Dirickson Creek, which is the largest tributary of Little Assawoman Bay. The event was attended by Senator Tom Carper and members of the Dirickson Creek Team. The Team is a group of local citizens who are concerned about water quality and advocate for public policies to improve water quality.

The primary finding of the report was that, as in much of the Inland Bays, nitrogen levels in the creek are far too high. This nitrogen pollution comes from a variety of sources – agricultural runoff, lawn fertilizers, animal waste and faulty septic systems among others. Elevated levels of nitrogen drive algal growth which, through both respiration and eventual decomposition, can devastate dissolved oxygen levels which in turn, is harmful to fish populations.

Fortunately, nitrogen levels in the Inland Bays have been declining in recent years. This is due to the elimination of almost all point sources of nutrient pollution and may, counterintuitively, be due to the increase in development in the watershed as the tradeoff is frequently a reduction in agricultural land. (Agriculture can cause significant nutrient pollution due to fertilizer runoff.)

An additional finding of the report was that indicator bacteria levels were elevated in the creek and exceeded EPA standards for swimming at the Old Mill Bridge testing site. The “indicator” bacteria used in the preparation of the report were of the Enterococcus genus and are used because they are relatively easy to test for and frequently present in human and animal waste. These bacteria are not, themselves, harmful to humans but they do frequently occur alongside pathogens.

Without doing in-depth genotype assessments, it is impossible to know the source of the bacteria. It is possible that the bacteria are from natural sources – animal waste from wildlife in the area. Other potential sources include pet waste (always pick up after your dog!), runoff from livestock and poultry operations, or improperly maintained septic systems. Further research is needed to know the precise source.

But, the good news is that at Mulberry Landing the water quality is consistently safe for swimming – so don’t hesitate to bring your kayak or boat and get out there and enjoy the Bays!

Learn more about Dirickson Creek and view the full report here »