1

Session structure

•Overview

•Definition & examples

•Actions

•Outputs

•Challenges

•Exercises

Module 4 Control measures & risk reassessment

2

Overview

• Document existing and potential control measures

• Assess their effectiveness (validation)

• Recalculate risks accounting for existing control measures

• Prioritize risks

3

Module 4 Control measures & risk reassessment

Control measure definition:

Any action or activity that can be used to prevent, eliminate or reduce to an acceptable level any water safety hazard

4

Module 4 Control measures & risk reassessment

Examples – Control measures – low tech

Cover

Well headDesignated bucket

5

Module 4 Control measures & risk reassessment

Examples – Control measures

Module 4 Control measures & risk reassessment

6

Source water protected from livestock

Automated chlorine dosing system

Module 4 Control measures &

Actions

•Identify existing controls

•Document need for new control measures as necessary

7

Identify control measures

Assess effectiveness

Reassess risks Prioritize risks

Module 4 Control measures & risk reassessment

Actions continued...

•Assess effectiveness (normal & exceptional circumstances)

8

ValidationInvestigative activity to identify the effectiveness of

control measures. It provides the evidence that elements of the WSP can effectively meet the water

quality targets.

Module 4 Control measures & risk reassessment

Actions continued...

•Assess effectiveness (normal & exceptional circumstances)

•Monitoring

•Not in isolation but as part of process chain

•Data from studies / historical records

•Introducing contaminant – testing removal

•Sanitary surveys

9

Module 4 Control measures & risk reassessment

Actions continued...

• Reassess risks accounting for effectiveness of control measures

•Based on long-term average performance

•Highlight where controls are not in place

10

Module 4 Control measures & risk reassessment

Actions continued...

•Prioritize all identified risks

•Rank the reassessed risks

•Screen for critical risks

11

Module 4 Control measures & risk reassessment

Outputs

12

Module 4 Control measures & risk reassessment

Challenges

•Uncertainty in prioritizing risks

•Lack of knowledge

•Poor data

•Different approaches = different outcome

•Qualitative versus quantitative

•Assessing effectiveness of certain controls

•Catchment – how to measure/enforce?

13

Module 4 Control measures & risk reassessment

14

Exercise•In small groups•Part 1 (5 minutes)

• Match up hazardous events with suitable control measures

• Identify possible control measures for three hazardous events

•Part 2 (5 minutes)• Describe how these control measures can be validated

•Part 3 and 4 (20 minutes)• Reassess the likelihood and severity by considering the

implementation of control measures and rank the risks again from highest to lowest

Module 4 Control measures & risk reassessment