EPA Science Inventory

MEETING IN MEXICO: NOWCASTING AND FORECASTING BEACH BACTERIA CONCENTRATION USING EPA'S VIRTUAL BEACH SOFTWARE

Citation:

FRICK, W. E. AND Z. GE. MEETING IN MEXICO: NOWCASTING AND FORECASTING BEACH BACTERIA CONCENTRATION USING EPA'S VIRTUAL BEACH SOFTWARE. Presented at AGU 2007 Joint Assembly, Acapulco, MEXICO, May 22 - 25, 2007.

Description:

Beaches in the United States of (North) America are subject to closure when bacterial counts exceed water quality criteria. Many authorities base these decisions on water samples that typically require at least 18 hours to analyze. This persistence approach, or model, often leads to erroneous decisions due to the great variability in bacterial concentrations. Beaches are closed when they could be open and vice versa, their true status unknown until the next day. Studies show that mathematical models based on multi-variable linear regression (MLR) principles can produce better estimates, or nowcasts, using real-time explanatory variables, such as turbidity, cloud cover, and rainfall. To make such models generally available, the Environmental Protection Agency (EPA) is developing a program called Virtual Beach (VB). VB is public-domain software for developing site-specific predictive models. It features capabilities that make it possible with reasonable effort to develop, and compare the performance of, static and dynamic MLR models. The results of tests on 2006 Huntington Beach, Lake Erie beach data are presented. In addition to nowcasting, the work begins to address the question, can weather and water forecasts be used to forecast beach conditions in advance? A preliminary affirmative answer is provided based on an analysis of the Huntington Beach data, with weather forecasts for nearby Cleveland-Hopkins international airport, and NOAA lake condition forecasts. We encourage those engaged in beach monitoring and management to request VB, applying the nowcast and forecast models developed with it to their locations of interest.

Purpose/Objective:

A main objective of this task is to combine empirical and physical mechanisms in a model, known as Visual Beach, that

  • is user-friendly
  • includes point and non-point sources of contamination
  • includes the latest bacterial decay mechanisms
  • incorporates real-time and web-based ambient and atmospheric and aquatic conditions
  • and has a predictive capability of up to three days to help avert potential beach closures.
The suite of predictive capabilities for this software application can enhance the utility of new methodology for analysis of indicator pathogens by identifying times that represent the highest probability of bacterial contamination. Successful use of this model will provide a means to direct timely collection of monitoring samples, strengthening the value of the short turnaround time for sampling. Additionally, in some cases of known point sources of bacteria, such as waste water treatment plant discharges, the model can be applied to help guide operational controls to help prevent resulting beach closures.

URLs/Downloads:

Record Details:

Record Type: DOCUMENT (PRESENTATION/ABSTRACT)
Start Date: 05/22/2007
Completion Date: 05/22/2007
Record Last Revised: 05/23/2007
Record Created: 03/07/2007
Record Released: 03/07/2007
Record ID: 165685

Organization:

U.S. ENVIRONMENTAL PROTECTION AGENCY

OFFICE OF RESEARCH AND DEVELOPMENT

NATIONAL EXPOSURE RESEARCH LAB

ECOSYSTEMS RESEARCH DIVISION

REGULATORY SUPPORT BRANCH