U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2010–3093

October 2010

Understanding Beach Health Throughout the Great Lakes—

Entering a New Era of Investigations

Printed on recycled paper

Water recreation and associated 

tourism provide wide-ranging economic 

opportunities and societal benefits to

the Great Lakes Region. Unfortunately, 

coastal areas can become contaminated 

with pathogens (disease-causing microorganisms) of fecal origin that threaten 

the health of people who swim in coastal 

waters. Beach advisories and closures are 

intended to protect swimmers from illness caused by fecal contamination; however, several problems face beach managers who issue advisories or closures or try 

to solve contamination problems: 

•	 Traditional lab analyses for beach 

water quality take too long. Current 

beach water-quality monitoring relies 

on culturing of fecal-indicator bacteria, 

such as E. coli or enterococci. Although 

not necessarily pathogenic, these bacteria are considered to be indicators of 

contamination from human and (or) animal waste. Unfortunately, results aren’t 

available until at least 18–24 hours 

after sampling, so bacteria counts may 

have changed by the time management 

decisions are made. Too often, beaches 

are closed or placed under advisory 

too late to protect visitor health or are 

closed unnecessarily, which keeps visitors out of relatively safe water. Rapid 

assessments are needed to improve 

the timeliness and accuracy of beach 

closures and advisories. 

•	 Sources of fecal contamination in 

recreational waters are often unknown. 

This makes it difficult to assess the

extent of fecal contamination and take 

remedial actions. Relations between 

coastal processes, such as sediment 

transport and wave action, and bacteria concentrations from nonpoint 

sources need to be comprehensively 

studied in the Great Lakes. Methods 

that can distinguish between human 

and animal fecal contamination also 

need to be developed and applied to 

help identify risks associated with 

contaminated recreational waters. 

•	 Recreational waters are seldom monitored for actual pathogens. Fecal indicator bacteria do not necessarily have 

the same transport and survival properties as all pathogens. Beach managers 

need data on the types of potential 

pathogens present, the relation of 

the pathogens to indicator-organism 

concentrations, and options for other 

parameters—such as environmental 

conditions—that correlate well with 

pathogens and potential swimmingrelated illness at their beaches. 

•	 Data used in the study of recreational 

waters are sometimes inconsistent 

between beaches because data currently are compiled by numerous 

agencies and in a wide variety of 

formats. Improved Great Lakes-wide 

data reporting, data consistency, and 

data accessibility are needed to better 

facilitate analysis, interpretation, and 

communication among those who 

monitor, evaluate trends, or do research 

at beaches.

Overall Mission

For over a decade, the U.S. Geological Survey (USGS) has been a leader in 

the science of beach health. The overall mission of this work is to provide 

science-based information and methods that will allow beach managers to 

more accurately make beach closure 

and advisory decisions, understand the 

sources and physical processes affecting 

beach contaminants, and understand 

how science-based information can be 

used to mitigate and restore beaches 

and protect the public. The work consists 

of four science elements—real-time 

assessments; pathogens and microbial 

source tracking; coastal processes; and 

data analysis, interpretation, and communication—which are described in the 

remainder of this fact sheet.

Key Questions for USGS 

Research

•	 Are there better ways to inform the 

public whether they can use a beach 

without risking their health?

•	 How do new rapid analytical methods 

compare to traditional methods for 

determining concentrations of fecalindicator bacteria at beaches?

•	 Are pathogens present at beaches? If 

so, how do they get to the beach, and 

what is their source?

•	 How do sand movement and wave 

action on the beach affect fecal-indicator-bacteria and pathogen concentrations in the lake water?

•	 What are the best indicators of pathogenic microorganisms?

•	 With so many potential sources of 

fecal contamination at a beach, what 

methods can be used to distinguish the 

contributions from humans?

•	 What characteristics of beaches contribute most to influencing bacterial

indicator and pathogen concentrations 

in beach sands and groundwater?
Real-Time Assessments 

Real-time assessments can be done 

by means of predictive models and (or) 

rapid analytical methods. Predictive models use easily measured environmental 

and water-quality variables, such as rainfall amounts and water clarity (turbidity), 

to estimate current recreational waterquality conditions, thus allowing the 

beach manager to evaluate the need for 

an advisory or closing. Nowcast systems, 

based on predictive models, are used to 

provide model results to the public (for 

Pathogens and Microbial Source 

Tracking

USGS researchers are working to 

determine the occurrence of microbial 

source tracking (MST) markers and 

pathogens of concern for human health at 

beaches susceptible to various sources of 

fecal pollution. Methods for identifying 

or enumerating pathogens include laboratory culture for bacterial pathogens and 

molecular methods, such as qPCR, for 

all types of pathogens. MST molecular 

markers—segments of genetic material 

that can be used to indicate potential 

sources—have been used to link fecal 

contamination in the environment back 

to humans or animals as sources. MST 

techniques can also be applied to identify 

contaminant sources at beaches. Current 

activities include the following:

•	 Developing and applying sampling 

strategies and analytical methods for 

Nowcasting at Great Lakes Beaches

A nowcast is a system that uses environmental and (or) water-quality “variables” (such as 

turbidity and rainfall amounts) measured in real time to estimate recreational water quality. The 

USGS is working with local agencies in Illinois, Indiana, Ohio, Pennsylvania, Michigan, New 

York, and Wisconsin to establish nowcast systems at over 25 Great Lakes beaches. 

The Ohio Nowcast (www.ohionowcast.info) is an operational system for two Lake Erie 

beaches—Huntington in Bay Village and Edgewater in Cleveland. The Ohio Nowcast provides 

the probability (in percent) that the Ohio bathing-water standard of 235 colony-forming units per 

100 milliliters for E. coli will be exceeded. A threshold probability is established on the basis of 

historical data; when the probability is above the threshold, the beach is posted with an advisory.

Since the Ohio Nowcast began operation in 2006, the nowcast models have provided more 

accurate estimates of water-quality conditions than have the use of the previous day’s E. coli 

concentration (the current method used by most beach managers) (Francy and others, 2009). 

Most importantly, using the models, beach managers were better able to predict when the E. coli

standard was exceeded and issue advisories to the public. The USGS continues to work with 

local agencies to improve the accuracy of the Ohio Nowcast. 

MST markers and bacterial, protozoan, 

and viral pathogens.

•	 Identifying the relationship between 

fecal-indicator bacteria concentrations 

and pathogen or MST marker detections 

or concentrations.

•	 Identifying environmental conditions 

that are associated with pathogen occurrence, such as rainfall, wave frequency 

and magnitude, and contributions from 

streams that empty into coastal waters.

•	 Identifying whether sand or algae are 

reservoirs for enteric organisms and may 

release pathogens to the water column 

and affect recreational water quality.

•	 Developing a categorization of beach 

types using bacterial indicators, pathogens, and MST markers as criteria. 

These categories can then be used by 

researchers to help design a pathogenand MST-monitoring strategy.

Determining Regional Influences on 

E. coli Fluctuations

Previous studies by the USGS 

(Nevers and Whitman, 2008; Whitman 

and Nevers, 2008) have determined that 

a persistent background concentration of 

E. coli in the nearshore waters of Lake 

Michigan affects multiple beaches. The 

background E. coli combines with local 

example, www.ohionowcast.info; see box 

below). Rapid analytical methods such 

as quantitative polymerase chain reaction 

(qPCR) and immunomagnetic separation/adenosine triphosphate (IMS/ATP) 

can provide analytical results within 2–3 

hours. 

USGS researchers are working to 

further develop and expand functional 

real-time assessments to more locations 

around the Great Lakes and provide 

assessment tools and training to beach 

managers. Current activities include the 

following:

•	 Exploring the use of new variables that 

explain physical and biological processes affecting fecal-indicator bacteria 

concentrations.

•	 Testing alternative statistical techniques to improve the accuracy of 

model predictions.

•	 Providing an automated modeling 

system to better enable technology 

transfer to beach managers.

•	 Providing training and technology 

transfer to beach managers to apply 

and evaluate rapid analytical methods.
Coastal Processes 

Coastal processes that may influence

bacteria concentrations include longshore 

currents and sediment transport, surfacewater contributions, turbulence associated 

with currents and wave action, changes 

in lake and groundwater water levels, and 

seiches. Beach sand and Cladophora (a 

filamentous green algae) potentially accumulate bacterial indicators and pathogens 

for release into lake waters. 

USGS researchers are working to 

characterize the transfer of bacterial indicators, pathogens, and MST markers to 

the nearshore waters, sediments, groundwater, and lake water. Current activities 

include the following:

•	 Determining the role of groundwater 

as a source of bacterial indicators and 

pathogens to lake water.

•	 Evaluating the role of surface and 

buried beach debris and algae on concentrations of bacterial indicators in 

foreshore beach sands and submerged 

sediments.

•	 Determining the relations between 

various environmental conditions and 

sediment dynamics.

•	 Expanding the geographic extent of 

studies of coastal processes over a 

range of beach types.

Coastal Processes at Great Lakes Beaches

Coastal processes that affect fecal-indicator bacteria and pathogen concentrations 

at Great Lakes beaches are not well understood. At one Lake Erie beach—Edgewater, 

Cleveland, Ohio—past studies indicated that shallow groundwater and waves influence

the storage and accumulation of E. coli in foreshore sands (Francy and others, 2006). 

Work was done during the recreational season of 2008 to help researchers better understand this phenomenon.

Six piezometers (shallow water wells) were installed. Four were buried at 2, 4, 7, 

and 10 feet from the swash zone (the zone of the shoreline that is constantly washed by 

waves or tides), and two were installed at 20 and 80 feet from the swash zone. Pressure transducers were installed in two of the piezometers. Data on water levels, water 

temperature, specific conductance, pH, turbidity, enterococci, and E. coli concentrations 

were collected 4 days a week from June 6 through 

August 14, 2008. 

Over 150 groundwater and lake water samples 

were collected. Enterococci and E. coli concentrations greater than 100,000 colony-forming units per 

100 milliliters (CFU/100 mL) were found on multiple days in groundwater samples, but the highest 

concentrations in lake water were only 1,300 and 

1,400 CFU/100 mL, respectively. 

Bacterial Pathogens at Beaches

Health effects associated with swimming and the handling of sand have been 

identified by epidemiological studies at Great Lakes beaches (Wade and others,

2008; Heaney and others, 2009). In recreational waters, pathogens implicated in 

waterborne human disease include several bacteria transferred among humans and 

animals, as well as human enteric viruses. A recent U.S. Environmental Protection 

Agency review (2009) notes that much remains to be learned about occurrence, 

sources, and human-health significance of pathogens in recreational waters where

human waste is not a major contaminant source. As a follow-up to preliminary studies at two Great Lakes beaches, the USGS has begun a comprehensive study evaluating the presence of key bacterial pathogens and MST markers at 12 beaches across 

the Great Lakes. The 12 beaches were selected to represent a wide array of potential 

sources and typical Great Lakes environmental settings. Results of over 400 samples 

being analyzed in 2010 will provide data on sources of fecal contamination, help 

to identify human health risk, and facilitate the relation of pathogen occurrence to 

fecal-indicator bacteria concentrations and environmental factors.

sources at specific beaches, and these

local and background sources influence overall E. coli concentrations and 

therefore beach-monitoring results. The 

co-occurrences of E. coli concentrations 

with other fecal indicators and markers of 

various types of contamination are being 

explored so that immediate and persistent 

sources can potentially be eliminated. 

To examine bacterial transport in the 

region, water samples from representative beaches along the southern coast of 

Lake Michigan are being analyzed, and 

instruments to measure water and current 

conditions are being deployed at advantageous locations. Future research will 

expand the region of focus and increase 

the number of genetic and fecal markers 

analyzed so that the influence of largescale lake processes on beach water quality can be determined.
Improving Great LakesWide Beach-Data Analysis, 

Interpretation, and Communication

USGS researchers are working to 

compile recreational-water-quality data on 

Great Lakes beaches into comprehensive 

databases and a Geographic Information System (GIS) that will facilitate the 

assembly of USGS data and enhance 

the communication of this information 

to beach managers and the public. The 

GIS could encompass multiple scales of 

analysis, enabling beach-pollution factors 

(such as tributaries or stormwater outfalls) 

and land-use factors to be represented in 

spatial models of beach-bacteria dynamics. A multiagency database could be used 

to incorporate data into predictive models 

and other diverse research activities. Current activities include the following:

•	 Developing a publicly accessible, 

Web-based, interactive GIS that allows 

visualization of Great Lakes-wide 

water-quality and environmental data 

associated with beaches.

•	 Developing a comprehensive database 

to assemble environmental data collected at Great Lakes beaches.

•	 Developing a comprehensive database 

that integrates real-time data (such as 

rainfall) from additional sources, such 

as the National Oceanic and Atmospheric Administration, with beachcollected data.

•	 Exploring ways to use an integrated, 

central database in development of 

predictive models.

Program Information

Funding for USGS beach projects and research in the Great Lakes comes from 

a variety of sources including the Ocean Research Priority Plan, the USGS, the Great 

Lakes Restoration Initiative, the U.S. Environmental Protection Agency (USEPA), and 

many state and local partner agencies and organizations throughout the region.

Development of a Geographic-Information-System-Based Beach Visualization and 

Analysis Tool

USGS has initiated the first comprehensive assembly of Great Lakes beach and

coastal data. A wide array of spatially referenced beach information, including bacterial 

beach-monitoring data for 2007 through 2009, has been incorporated into a Geographic 

Information Systems (GIS)-based internet mapping application called the Great Lakes 

Beach Analysis Tool. The tool enables users to view Great Lakes beach monitoring 

data, examine the physical setting (land cover, topography, geology, and so forth), link 

to sites that serve relevant real-time data 

(wind velocity and direction, wave height, 

rainfall, and so forth), and potentially 

visualize patterns of beach bacterial water 

quality around the Great Lakes. The tool 

is being developed as an example, and 

perhaps a template, for assembling and 

communicating Great Lakes beach data. It 

is currently (August 2010) in beta-version 

review by numerous potential users of the 

final product, and their input will guide

further development. 

Contact

James R. Morris, Director

USGS Ohio Water Science Center

6480 Doubletree Avenue

Columbus, OH 43229-1111

614-430-7700

dc_oh@usgs.gov

http://greatlakesbeaches.usgs.gov/

References

Francy, D.S., Bertke, E.E., and Darner, 

R.A., 2009, Testing and refining

the Ohio Nowcast at two Lake Erie 

beaches—2008: U.S. Geological Survey Open-File Report 2009–1066, 20 

p., accessed August 19, 2010, at http://

pubs.usgs.gov/of/2009/1066/.

Francy, D.S.; Bertke, E.E.; Finnegan, 

D.P.; Kephart, C.M.; Sheets, R.A.; 

Rhoades, John; and Stumpe, Lester, 

2006, Use of spatial sampling and 

microbial source-tracking tools for 

understanding fecal contamination at 

two Lake Erie beaches: U.S. Geological Survey Scientific Investigations

Report 2006–5298, 29 p.

Heaney, C.D., Sams, E., Wing, S., Marshall, S., Brenner, K., Dufour, A.P., and 

Wade, T.J., 2009, Contact with beach 

sand among beachgoers and risk of illness: American Journal of Epidemiology, v. 170, no. 2, p. 164–172.

Nevers, M.B., and Whitman, R.L., 2008, 

Coastal strategies to predict Escherichia coli concentrations for beaches 

along a 35 km stretch of southern Lake 

Michigan: Environmental Science & 

Technology, v. 42, p. 4454–4460.

Wade, T.J., Calderon, R.L., Brenner, 

K.P., Sams, E., Beach, M., Haugland, 

R., Wymer, L., and Dufour, A.P., 

2008, High sensitivity of children to 

swimming-associated gastrointestinal 

illness—Results using a rapid assay of 

recreational water quality: Epidemiology, v. 19, no. 3, p. 375–383.

Whitman, R.L., and Nevers, M.B., 2008, 

Summer E. coli patterns and responses 

along 23 Chicago beaches: Environmental Science & Technology, v. 42, 

p. 9217–9224.