Standardised survey method for identifying catchment risks to water quality

• Published in: Journal of water and health Vol. 14; no. 3; pp. 349 - 368
• Main Authors: Baker, D L, Ferguson, C M, Chier, P, Warnecke, M, Watkinson, A
• Format: Journal Article
• Language: English
• Published: England IWA Publishing 01.06.2016
• Subjects: Agrochemicals; Catchment area; Catchments; Chemical contaminants; Chemical pollution; Contaminants; Councils; Data processing; Drinking water; Drinking Water - microbiology; Drinking Water - parasitology; E coli; Environmental Monitoring - methods; Environmental protection; Escherichia coli; Hazards; Infrastructure; Mathematical analysis; Matrices (mathematics); Medical research; Methods; Microorganisms; Onsite; Pathogens; Pesticides; Point source pollution; Polls & surveys; Pollution sources; Quality management; Queensland; R&D; Recreation; Research & development; Risk; Risk assessment; Sewage; Sewer systems; Software; Software development tools; Stormwater; Surveying; Water Pollutants, Chemical - analysis; Water Quality; Water shortages; Water supply; Queensland; Australia; United States > US; Switzerland; Canberra Australian Capital Territory Australia
• ISSN: 1477-8920; 1996-7829
• DOI: 10.2166/wh.2015.054

This paper describes the development and application of a systematic methodology to identify and quantify risks in drinking water and recreational catchments. The methodology assesses microbial and chemical contaminants from both diffuse and point sources within a catchment using Escherichia coli, protozoan pathogens and chemicals (including fuel and pesticides) as index contaminants. Hazard source information is gathered by a defined sanitary survey process involving use of a software tool which groups hazards into six types: sewage infrastructure, on-site sewage systems, industrial, stormwater, agriculture and recreational sites. The survey estimates the likelihood of the site affecting catchment water quality, and the potential consequences, enabling the calculation of risk for individual sites. These risks are integrated to calculate a cumulative risk for each sub-catchment and the whole catchment. The cumulative risks process accounts for the proportion of potential input sources surveyed and for transfer of contaminants from upstream to downstream sub-catchments. The output risk matrices show the relative risk sources for each of the index contaminants, highlighting those with the greatest impact on water quality at a sub-catchment and catchment level. Verification of the sanitary survey assessments and prioritisation is achieved by comparison with water quality data and microbial source tracking.