Distribution System Modeling: Contamination Warning Systems & … · 2008. 7. 29. · intentional contamination threats Each dot (junction) represents. ... information to provide

Office of Research and DevelopmentNational Homeland Security Research Center

U.S. EPA Office of Research and Development (ORD) and EPA Region 2 Workshop:

The Science and Technology behind our Homeland Security Responsibilities

Robert Janke (EPA)

Distribution System Modeling: Contamination Warning Systems & Responding to ContaminationEvents


Acknowledgements

• EPA Colleagues: Regan Murray & Terra Baranowski• Collaborators:

–University of Cincinnati–Sandia National Laboratories–Argonne National Laboratory

• American Water Works Association–Kevin Morley

• Partnering Water Utilities (TEVA Utilities)–10 collaborating water utilities–Greater than 20 water utilities from across the country


Overview

• NHSRC’s Modeling & Simulation Work– WIPD Research program for distribution system modeling & simulation– Role of water utilities

• Background & Motivation for Contamination Warning Systems (CWS)

– Contamination threats to water systems– Need & role of CWS– TEVA-SPOT & CANARY

• Tools and methodologies to improve the security of distribution systems

– CWS design – TEVA-SPOT– Contamination Event Detection – CANARY– Next generation of tools, e.g., real-time modeling & improving distribution

system models


WIPD (TEVA) Research Program

• Objective: To improve water security through the development of models and software tools that help– Increase understanding of drinking

water distribution system dynamics– Reduce vulnerability to contamination

events– Improve operation of distribution

systems– Assist with utility response to

contamination events• Central to our research work has been

our partnership with AWWA and Water Utilities


What are the threats to water systems?

• Physical• Cyber• Contaminant

–What do we know about contaminant threats?


We know…• Distribution systems, via service connections, are arguably the most vulnerable component of a water system

• Certain biological and chemical contaminants pose a significant threat

• Release of a contaminant into a distribution system does not require sophisticated equipment

• Distribution systems currently offer little or no protection against intentional contamination threats

Each dot (junction) representsgroup of service connections. Lines represent pipes.

Tank

Distribution System Model


We know…cont’d

• Human health impacts will vary depending on the distribution system

• Significant health impacts can occur miles from the injection location

• Maximum exposures and human fatalities could range from 100’s to many 1,000s depending on:–Contaminant and its

concentration– Injection duration and quantity–Location of attack

• The location of the contaminant release is important


Making the case for Contamination Warning Systems (CWS)…

• Contamination Warning Systems–Provide the ability to collect, integrate, analyze, and communicate

information to provide a timely warning of potential water contamination incidents and initiate response actions to minimize public health and economic impacts

• Are there alternatives to Contamination Warning Systems?–Back-flow preventers?–Point-of-use treatment devices?


Contamination Warning Systems

• Goals:– Detect a broad range of contamination events in drinking water

distribution systems – Detect rapidly enough to allow for utility and public health intervention that

reduces public health and economic impacts– Achieve multiple benefits to water utility

• Design principles:– Spatial coverage:

• Entire distribution system service area.– Contaminant coverage:

• All contaminant classes posing a threat.– Timing of detection:

• In sufficient time to allow for effective response.– System reliability:

• Information sufficient to make response decisions.– Deployable at water utilities of all sizes and types


What is TEVA-SPOT?• A software tool that allows the user to evaluate potential contamination

threats to drinking water distribution systems to:– Quantify public health and economic impacts– Design and evaluate monitoring strategies to mitigate and respond to

such impacts

TEVA-SPOT & CANARY

What is CANARY?• A software tool that takes standard water-quality data (e.g., chlorine,

TOC, conductivity, ORP) and uses mathematical algorithms to identify the onset of periods of anomalous water quality, while limiting the number of false alarms that occur.


TEVA-SPOT: Features and Impact

Contaminant Consequence Features:• Simulate contamination events in a distribution system

– Single contamination events– Multi, simultaneous contamination events

• Define contamination event ensembles:– All nodes, non-zero demand nodes, or user defined– Nodes defined by diameter of pipes which they are connected to

• Select exposure and dose response model• Results to quantitatively rank contamination scenarios, examine individual scenarios

by receptors impacted, determine the timeline of exposure and health impacts

Impact:• Assess contamination event consequences and timeline• Support the optimal design of sensor networks


TEVA-SPOT: Features and Impact Cont’d

Sensor Network Design Features:• Scalable solvers for large-scale problems

– 10,000s junctions and pipes• Solvers that can optimize many different objectives• Flexible specification of performance constraints• Fast solvers• Methods for rigorously evaluating solver performance

Impact:• Ability to design optimal sensor networks and evaluate alternative designs, e.g.,

expert designs or designs constrained to public facilities• Results to quantitatively evaluate sensor network designs, including graphical plots

depicting sensor coverage plots of contamination events


CANARY: Contamination Event Detection

Problem– Water quality data is noisy

• Operational events• Daily and seasonal patterns• Mixing source waters

– Contaminants may affect water quality signals but their signals are difficult to distinguish from the background noise

Event Detection Systems– Analyze water quality signals in real time – Differentiate anomalous events from

background variability– Focus on classical statistical and time series

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CANARY: Features and Impact

Features:• Runs on flexible number of monitoring sites

– Analyzed at central location• Can analyze any time series data• Easy to configure for specific locations• Stable in real-time applications

Impact:• Implemented as part of EPA’s Water Security Initiative (WSI)• Implemented at EPA’s T&E Facility• Only open-source tool for water quality event detection


Application and testing of TEVA-SPOT & CANARY

• AWWA User’s Group– Tested collaborating utilities (TEVA-SPOT: 10 utilities & CANARY: 2

utilities)– Several utilities are interested in piloting CANARY this year

• EPA’s WSI Pilot Program– TEVA-SPOT designed sensor network. CANARY currently running in real-

time at pilot city as part of a one-year evaluation of 2 event detection systems

• EPA’s T&E Facility– CANARY supported by contaminant testing in pipe loop studies (>20

contaminants)• Documentation

– Several published scientific articles and conference presentations on methodology and application

– Workshop at 2008 AWWA Water Security Congress– Software available & working towards commercialization


Contamination Warning Systems must be…

• Robust to varying seasonal and operational conditions within the water distribution system

• Provide greater return on investment, i.e., security concerns cannot be the only driver. Need for dual benefits, e.g.,:– Improved, more efficient operations, i.e., lower energy costs– Improved water quality– Lower regulatory costs

• Facilitate rapid response capabilities to address contamination events in real-time, e.g.,– Determine where best to flush fire hydrants or close valves and the

benefits of administering “Do Not Drink” or “Do Not Use” orders


However…

• Most utilities operate their distribution system based on– Historical practices, i.e., “operator” approach to managing water system

operations– Further, operations are not typically well integrated with the distribution system

model

• Most distribution system models are limited by:– Lack of regular updates and maintenance– Lack of data and understanding about parameter uncertainty and variability– Inability to automatically adapt models in real-time, based on system

operation, hydraulic, and water quality SCADA data


To address these issues…

• We are working to develop software tools which enable:– Thorough testing of CWS, including event detection systems– Real-time modeling capabilities– Effective and timely response to contamination events

• Outcomes include…– Real-time models, which rely on precise infrastructure models and

optimal algorithms for informed decision making– Improved distribution system models, which replace historical “operator”

approach to managing water system operations– Demonstration of dual-benefits to water utilities from the implementation

of real-time contamination event detection systems, and the integration of information from such systems into their routine operational and strategic planning processes


A look at these tools…

To accomplish many of our water security goals, we are creating add-ons to EPANET:

Planned Extensions•Real-time modeling•Contaminant back-tracking•Response, hydraulic response tool•Multi-Species contaminant modeling•Monte-Carlo - realistic modeling tool•Distributed Processing tool

All work in conjunction with EPANET


EPANET-RTX (Real-time eXtension)

• EPANET-RTX–An extension to EPANET that allows for real-time

estimation of water demands using real-time hydraulic measurements of pressure and flow rate

–Will improve contamination event detection and contamination source identification

–Will improve distribution system models and operations

• Currently under development


EPANET-BTX (Back Tracking eXtension)

• EPANET-BTX is an extension to EPANET that helps to determine the source location of a contamination incident –Algorithm calculates all flow paths

that lead to a particular output network node at a particular time

–For each flow path, the algorithm defines weights that accurately describe the relative influence of each path on water quality at the output location



Hydraulic Response Tool

• Once a contamination warning system detects the event, possible corrective actions are examined to determine best response– If concentration in a sensor node is greater than the detection limit, then

response is possible

• Hydraulic response tool can aid the identification of a hydraulic response following a contamination event– Locations of hydrant(s) to flush and/or valve(s) to close

• Case study testing currently underway– Initial results presented at AWWA Water Security Congress, Cinti, Ohio,

April, 2008


EPANET-MSX (Multi-Species eXtension)

• EPANET-MSX is an extension to EPANET that allows for the modeling of multiple interacting contaminants in drinking water pipe networks.

• EPANET-MSX is both a command-line executable, and an application programming interface (API), which is used in conjunction with the EPANET Toolkit

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EPANET-MCX (Monte Carlo eXtension)

• EPANET-MCX is a stand-alone C application that integrates EPANET and EPANET-MSX with the general Monte Carlo simulation package MCSIM (http://fredomatic.free.fr/page_mcsim.html).

• MCX will allow the user to define and assign probability distributions to particular EPANET model parameters. This specification of a Monte Carlo simulation is coded in the MCSIM simulation specification language, along with an EPANET input file that defines the network and its parameters.

• EPANET-MCX will allow the realistic modeling and simulation of contaminant release, impact assessment, event detection and response.



EPANET-DPX (Distributed Processing eXtension)

• EPANET-DPX is a stand alone Java application that schedules execution of multiple EPANET (or EPANET-MSX) input files for parallel execution on distributed processors. The processors may be part of a dedicated cluster, or individual machines networked to a common fileserver. Simulation results are collected in a central database on the file server, and an API is available for writing applications that process the database results.

• EPANET-DPX helps solve computationally difficult problems through distributed computing


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Distribution System Modeling: Contamination Warning Systems & … · 2008. 7. 29. · intentional contamination threats Each dot (junction) represents. ... information to provide