IDDE Case #2011-13

The City of Bainbridge Island’s Water Quality and Flow Monitoring Program status and trends monitoring revealed that Manzanita Creek is impaired by fecal coliform bacteria and does not meet Washington State Fecal Coliform Bacteria Criteria for both Water Year (WY)2010 and WY2011 (see Table 1). State criteria Part I stipulates that the geometric mean must not exceed 50 colonies/100mL, and Part II stipulates no more than 10% of samples can exceed 100 colonies/100mL (WAC 173-201A ). Both Parts I and II criteria must be met.

Table 1. Manzanita Creek Fecal Coliform Bacteria Concentrations (colony forming units/100mL)
Water Year (WY)	Geomean1	Meets Part I?	# > 100	< or = 10%	Meets Part II?
2010	N/A	N/A	4	No	No
2011	228	No	11	No	No
1. Must have at least 5 values to calculate a geomean.

Manzanita Bay and adjacent western shorelines to the north and south of the bay are critical commercial shellfish growing and harvest areas that have recently been closed to harvest due to fecal coliform bacteria contamination.

The Manzanita Creek Watershed contains several potential natural and anthropogenic (man-made) sources for fecal coliform bacteria to include:

· Light Industrial Park
· Compost/Mining Facility
· Golf Course
· Failing residential onsite septic systems
· Pet Waste
· Agriculture
· Livestock Farms
· Wildlife

In accordance with the City’s National Pollutant Discharge Elimination System (NPDES) permit, the City is required to identify and eliminate pollutants through the Illicit Discharge Detection and Elimination (IDDE) Program.

The project consists of three phases (see Table 2 for project timeline).

Phase I – Preliminary Confluence/Choke Point Sampling is designed to identify particular problem reaches within the Manzanita Creek Watershed by sampling and assessing bacterial concentrations at critical confluence points or choke points along the mainstem and tributaries (see site map above).

Phase II – Targeted Sampling within Problem Reaches is designed to further identify likely sources through more complex sampling such as ammonia-nitrogen (urea), surfactants (soaps), or other indicator parameters and assessing land-use along the effected reach(es).

Phase III - Source Confirmation and Elimination is designed to pinpoint actual sources and work cooperatively with effected property owners or business owners to eliminate the source. This phase may include joint efforts with the Kitsap Conservation District, the Kitsap Public Health District, or Department of Ecology as deemed appropriate.

Table 2. Project Timeline

Phase	Start Date	Status
I	July 14, 2011	Complete
II	August 4, 2011	Complete
III	September 12, 2011	In Progress