Early Warning Systems (EWS) Protect Water Supplies at the Source

Every water body is under the threat of pollution, and every water intake is vulnerable to major spills or constant pollutant intrusions.  An unexpected spill can seriously impair the quality of drinking water.  Real-time monitoring networks are valuable tools for source water protection efforts. Commonly referred to as “early warning systems” or “EWS” for short, they help water systems gain precious time to make informed decisions and formulate a response in the case of a contamination event, when time is of the essence.  Time is critical to putting an emergency response plan into operation, or implementing a procedure change at the water treatment plant.

An early warning system is a key component of the spill response program and intake water protection program, and as such, it is an integral part of a broad source water protection effort. The system can be used to provide timely information on the quality of the source waters so that knowledgeable decisions can be made concerning treatment and operation responses.

Decisions could include closure of intakes; alternative source water; special intake operation mode (e.g., selective depth withdraw); applying special treatment and operation practices at the water plants.

The primary emphasis in early warning systems is to gain information at an acceptable level of accuracy and in a very timely manner.  They offer continuous and near real-time data, specific and comprehensive.

Early warning systems can also serve as “cops on a beat.” Their very presence can help to discourage illegal activity, such as dumping of contaminants into waterways.   Early warning systems include a network of water quality monitors linked to a website and data management system, and an upstream-downstream notification system that allows the EWS participants, including water utility personnel, emergency responders, government agencies and industry representatives to share information about source water quality and emergency or contamination events.

Example of an Early Warning System

With the growing concern surrounding the potential impacts of natural gas drilling and associated activities, the Susquehanna River Basin Commission (SRBC) established the Remote Water Quality Monitoring Network (RWQMN) in January 2010. The system of 51 monitoring stations continuously measures and reports water quality conditions of smaller rivers and streams located in northern tier Pennsylvania and southern tier New York to help track existing water quality conditions and changes in them on an ongoing, real-time basis.

View WREN’s short video of the EWS along the Susquehanna River, known as the Remote Water Quality Monitoring Network (RWQMN).  Video highlights the role of early warning systems for source water protection titled “Early Warning System Protects Water Supplies at the Source. ” and features United Water’s Chad Bingaman, Andy Gavin and Susan Obleski (now retired) of SRBC.  WREN worked with GreenTreks Network to produce the video.


Sourcewater Early Warning System from GreenTreks Network


This “early warning system” complements SRBC’s  low flow protection requirements, environmental screening for water withdrawal approvals, aquatic resource surveys, and other established water quality monitoring programs, adding yet another layer of protection to the SRBC arsenal.

SRBC’s Remote Water Quality Monitoring Network is guided by six primary objectives:

  1. To establish a real-time monitoring network at areas of concern in the Susquehanna River Basin; network provides monitoring data to resource agencies, the regulated community and the public to allow timely response in the case of pollution incidents;
  2. To establish baseline water quality conditions in targeted areas of the basin;
  3. To verify whether or not the natural gas industry and/ or other activities with the potential to cause pollution incidents are causing adverse impacts on local water quality;
  4. To reduce the cost of data collection through the use of advanced technologies; to form collaborative partnerships to improve monitoring technology and provide educational opportunities;
  5. To enhance water supply protection through source water monitoring; and
  6. To be responsive to public concerns.

Learn More at SRBC’s website.

Other Early Warning Systems in Pennsylvania

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