The Need for an Integrated View of Water Quality Modeling and Monitoring Bruce Kiselica USEPA, Region 2 Second Workshop on Advanced Technologies in Real Time Monitoring and Modeling for Drinking Water Safety and Security Newark, New Jersey December 11-12, 2002

The Need for an Integrated View of Water Quality Modeling and Monitoring – or- what exactly is an “early warning system” and how do I go about putting one together?

What is an “early warning system” (EWS)? An EWS is a monitoring strategy that is capable of detecting an event with sufficient time for an appropriate response (ie., steps to protect public health).

Early Warning Systems Core of an EWS is the monitoring technology, that can detect or screen for toxic substances or infections microorganisms. An EWS is much more than a monitoring technology. It is an integrated system for: Deploying the monitoring technology, analyzing and interpreting the results and using the results in making decisions that are protective of public health while minimizing unnecessary concern and inconvenience within a community.

EWS Design Considerations System Characterization Planning and communication Target Contaminants Monitoring technology selection Alarm Levels Monitoring location and density Data management, interpretation and use

System Characterization Access points Flow and demand patterns Pressure zones System vulnerability to contamination threat

Planning and Communication Objectives of EWS program must be clearly defined Response guidelines and procedures need to be in place prior to an “event” (part of the Emergency Response Plan) Establish hierarchy for dissemination of “positive” monitoring results (utility supervisors, emergency response personnel, state/local health depts, law enforcement if terrorist activity suspected)

Planning and Communication (con’t) Response actions identified (ex., sampling and confirmatory analysis, preliminary mitigation measures and assessment of severity of the threat). Public notification (boil/don’t use water)- decisions made quickly with limited information and must balance need to protect public health with avoidance of unnecessary stress and burden on community.

Planning and Communication (con’t) Communication to the public- advertise EWS monitoring efforts vs. kept secret? May be best to communicate all efforts being taken of general preparedness for a variety of events or emergencies without focusing on intentional contamination.

Target Contaminants Review those that are considered to pose the most serious threat - given your systems vulnerabilities and ability of treatment barrier. One approach - tiered monitoring  first stage is continues, real-time screen for a range of contaminants. - if positive result...  second stage is confirmatory analysis using more specific and sensitive techniques - if positive result, response action taken.

Monitoring Technology Selection/Considerations Rapid response time - allows steps to be taken to prevent or minimize exposure of public to contaminant. Fully automated - 24/7 remote operation Screens for a range of contaminants Specific for the contaminants of concern Affordable cost - both capital and O&M

Monitoring Technology Selection/Considerations Sufficient sensitivity - should quantify at lowest level of health threat Low occurrence of false positives and negatives High rate of sampling - to identify toxicant introduced in one defined event Reliable and rugged - to withstand field conditions Requires minimal skill and training

Alarm Levels Baselines must be developed Alarm or trigger level is set some deviation from a baseline May consider multiple alarm levels. Lower alarm level triggers confirmatory analysis, while second alarm warrants an immediate response

Sensor Location and Density Source water (at intake structure and upstream with modeling considerations) Entry point to the distribution system Out in the distribution system (a network of sensors)  must characterize system - review usage patterns and potential targets (ex., hospitals, schools, gov buildings)  hydraulic model can assist in assessing placement

Data Management, Interpretation and Use Use of data acquisition software and central data management center is critical Individual sensors deployed must be equipped with transmitters, modems, direct wire or some other means to communicate to the central data management center Data management system should perform some level of data analysis and trending - to distinguish between genuine excursions and “noise”

Data Management, Interpretation and Use (con’t) When data management system detects an excursion above the alarm level- notification is necessary Notify operators, system management, etc. via redundant communication (page and fax)

Data Management, Interpretation and Use (con’t) System may be programmed to take initial response actions- closing valves or additional sampling Ultimate decisions will be influenced by:  Nature and magnitude of adverse event (ie., extent of public health impact that could occur)  Nature of response action established for such alarm level  Perceived risk of exposure

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