SPRINGBROOK CREEK
FECAL COLIFORM BACTERIA
WATERSHED INVESTIGATION
IDDE Case #2011-15
PROJECT OVERVIEW
PROJECT UPDATES:
Springbrook Creek drains approximately 1600 acres of the Fletcher Bay Watershed and discharges into Fletcher Bay. The creek’s tributaries and mainstem travel approximately 2.3 miles, originating near Head-of-the-Bay just west of Wyatt Way and flows northward to Fletcher Bay.
Washington State Department of Ecology’s 2008 Water Quality Assessment declared Springbrook Creek to be impaired for fecal coliform bacteria. The State listed the creek on the 303(d) List of Impaired Waterbodies, which lists waterbodies in need of a cleanup plan.
The City of Bainbridge Island’s Water Quality and Flow Monitoring Program status and trends monitoring revealed that Springbrook Creek continues to be impaired by fecal coliform bacteria 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 of the criteria must be met.
|
Table 1. Springbrook 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 |
3 |
No |
No |
|
2011 |
63 |
No |
5 |
No |
No |
|
1. Must have at least 5 values to calculate a geomean. |
|
|
|
Fletcher 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 Springbrook Creek drainage basin contains several potential natural and anthropogenic (man-made) sources for fecal coliform bacteria to include:
· Commercial Center
· 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 Springbrook 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 |
Note that the start dates for phases II and III are dependent upon the completion of the previous phase. However, in accordance with NPDES permit requirements, sources need to be identified and eliminated within 6 months.
