Decision support tool

Control measures

Examples for validation

Part of system Examples of measure Examples of validation
At different sites in the supply system (e.g. in the water body, filter drain, etc.) Continuous monitoring of cyanobacteria using turbidity or pigment fluorescence as indicators of cyanobacterial abundance. Validation of whether monitor signals adequately indicate cyanobacterial occurrence in your specific setting by performing cyanobacterial cell counts and/or biovolume determination. This may be different for different parts of the supply chain, e.g. for raw water and for filter outlets, and separate validation may be adequate.
Catchment Management measures to reduce nutrient loads by e.g. use restriction. Validate whether the measures implemented actually meet the targets set for nutrient load reduction by running specific research programmes to determine the load, e.g. by sampling tributaries under normal conditions and during heavy precipitation, or snowmelt events, and modeling nutrient budgets.
Water body Artificial mixing and/or biological measures to reduce cyanobacterial growth in a water-body. Monitoring of cyanobacterial growth, e.g. by weekly or fortnightly determination of biovolume (or other indicators of cyanobacterial biomass) and comparison of results with previous investigations at the same time of year.
Raw water abstraction Choice of offtake depths to minimise intake of cyanobacteria. Weekly or fortnightly determination of depth profiles of cyanobacterial occurrence, e.g. by determination of biovolume or in situ fluorescence, in a range of different situations of cyanobacterial occurrence and compare your plan for the selection of offtake depths to these findings.
Drinking water treatment Dosing of oxidant to remove, or of powdered activated carbon (PAC) to bind dissolved cyanotoxins. Evaluation of the amount needed at minimum to ensure cyanotoxin degradation / binding even in situations in which the system is challenged by high levels of competing organic carbon, as is the case during a cyanobacterial bloom. Such data may result in a scheme for dosing in relation to some indicator of cyanobacterial abundance that proves most useful to you, e.g. pigment fluorescence, biovolume or chlorophyll-a concentration analysis in the raw water.