Weeks Bay Watershed Project Management Plan - Mobile Bay ...

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Phosphate concentrations are usually less than 0.08 mg/L (the
analysis’ lowest detection limit) and are not of particular concern in
Weeks Bay Watershed. However, phosphate concentrations over 0.1
mg/L have been measured several times in Weeks Creek at CR 26 in
Magnolia Springs.
B. Human Health Threats
1. Presence of fecal coliform bacteria in some rivers and
creeks is potential threat to human health.
Fecal coliform bacteria are normal inhabitants of the intestinal tract
of all vertebrate animals. Their presence in surface or ground water
indicates contamination of these waters by animal waste, human,
domesticated or feral. They may reach surface waters directly from
the outfall of a wastewater treatment facility, from pleasure or
commercial boats, from surface water runoff, usually associated with
heavy rainfall or from concentrations of domestic animals in or
nearby streams.
The presence of fecal coliform bacteria in surface waters of the
Weeks Bay Watershed has been documented many times. A major
problem exists in determining the source of the pollution, whether
from human or animal waste. Sandy soils and a high ground water
table in much of the Watershed make effective on-site wastewater
treatment problematic in those areas. It has been estimated that
approximately 90 percent of the households in the Watershed rely on
septic tanks for wastewater treatment. At this time, no practical
method to determine how many septic tank systems are effectively
treating household wastewater is available.
In Weeks Bay Watershed, except during periods of excessive runoff,
fecal coliform counts for Fish River, Magnolia River and Weeks Bay
are consistently low. In contrast, streams in the upper Watershed
areas display more significant coliform counts. Table 6 lists
violations of the F&W fecal coliform single-sample count (2,000
colonies per 100 ml sample) standard that occurred at 10 percent or
greater (five violations or more) sampling events as documented by
the Geological Survey of Alabama. These stream reaches are shown
in Figure 7.
Weeks Bay NERR volunteers monitor for the presence of fecal
coliform bi-weekly at five sites in the Watershed. Water samples are
collected by volunteers and delivered to ADEM’s Mobile Field
Office for analysis. Results of monitoring by WBNERR indicate that
violations have occurred during 10% or more of the sampling events
in Corn Branch at CR 64 and in Turkey Branch east of CR 27.
Weeks Bay Watershed Management Plan