Beach Closures in Oakland
County, Michigan: Using GIS as an Investigative Tool
Jeanine Chura McCloskey
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EPA's Beach WatchThe beach closure problem became a large enough concern that the Environmental Protection Agency initiated the BEACH Program (Beaches Environmental Assessment, Closure, and Health) in 1997 with the goals of improving U.S. recreational waters and reducing the risk of disease to those who frequent the beaches. Among the official goals of this Beach Watch Program were: strengthening standards, improving beach programs at local governments, increasing communication with the public, and providing funding for research to improve detection methods to protect public health. The BEACH Program led to the passage of the BEACH Act (Beaches Environmental Assessment and Coastal Health Act) on October 10, 2000 ("Beach Act" 2). This Act amended the Clean Water Act and contains three "significant" provisions including:
Causes of Beach ClosuresCauses of beach closures are numerous. They include, but are not limited to, the following:
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Oakland County's
Procedures
Oakland County samples approximately 60 of their 286 beaches yearly; others are on a five-year rotation schedule. Beaches sampled each year include government owned properties, camps, and commercial beaches (or “pay to enter”) properties. In addition, any beach that has a history of high bacterial levels, is also sampled each year. Three 100ml samples of beach water, at waist level, are taken at each assigned beach each week. The samples are then analyzed for the presence of E-coli. Initially, if any one of the samples is greater than 300 E-Coli per 100ml the beach must be closed. After one month of sampling, a rolling geometric mean is calculated and the limit is 130 E-Coli per 100ml. The testing method is done on-site in the County’s laboratory and results are obtained after 18 hours. Last summer I had the privilege of interning with the County and worked on the beach program as one of several other responsibilities. The interns were responsible for sampling their assigned beaches for the amount of E-coli per 100ml at least once per week and determining whether or not the beach should remain open from the results of the tests. I had noticed throughout the summer that almost every time it rained it seemed as if many beaches would close the next day. Rainfall, indeed, has been shown to be a beach closure predictor for some beaches although its importance in terms of a determinant have been debated. In a study done in the UK, researchers claim that rainfall is only a minimal component stating that sunshine, wind, and catchment sources were much stronger predictors (Crowther et al. 4029). Other studies, however, claim that rainfall is a major component. Studies done in Australia indicated a “linear relationship between visual indicators and bacterial density . . . and rainfall alone as a predictor is equivalent to or better than visual assessment” (Armstrong et al. 249). Many beaches in Australia use rainfall determined from gauge stations throughout the country to prepare daily beach reports/closures (249). |
Hardware: Windows based machine. Software: ArcView 3.2 was used to analyze the rainfall and beach closure data. Microsoft Excel was used to create the data tables of the rainfall and beach closing information. Adobe photoshop was used to format all layouts for web use. Gamani Moviegear was used to create the animations. |
June 1998 Animation (scroll to
the right to see still frames):
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June 1998 Still Frames of Rainfall and Beach Closures: |
July 1998 Animation
(scroll to the right to see still frames):
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July 1998
Still Frames of Rainfall and Beach Closures:
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June 2001 Animation
(scroll to the right to see still frames):
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June 2001
Still Frames of Rainfall and Beach Closures:
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July 2001 Animation
(scroll to the right to see still frames):
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July 2001
Still Frames of Rainfall and Beach Closures:
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