Monitoring ambient water quality (indicator 6.3.2)

Indicator 6.3.2 "Proportion of bodies of water with good ambient water quality"

Target 6.3 sets out to improve ambient water quality - this page explains why and how to monitor progress towards the target, and what resources that are available for countries to do so
Wastewater from industry and agriculture can be detrimental to ambient water quality. Monitoring helps policy- and decision makers to identify water bodies at risk, and by combining water quality data with information about how the watercourse is being used, to direct interventions where they will have the greatest impact. Photo credit: Anna Kari

Wastewater from industry and agriculture can be detrimental to ambient water quality. Monitoring helps policy- and decision makers to identify water bodies at risk, and by combining water quality data with information about how the watercourse is being used, to direct interventions where they will have the greatest impact. Photo credit: Anna Kari

The indicator tracks the percentage of water bodies in a country with good ambient water quality. “Good” indicates an ambient water quality that does not damage ecosystem function and human health according to core ambient water quality parameters.

Overall water quality is estimated based on a core set of parameters which inform on major water quality impairments present in many parts of the world. For surface water, these parameters are dissolved oxygen, electrical conductivity, nitrogen, phosphorus and pH and for groundwater they are electrical conductivity, nitrate and pH.

The methodology calls for in-situ measurements of these water quality parameters. The measured values are compared to national target levels for the different parameters, and if values do not exceed the target level, the water body is classified as good

How to progressively Monitor?

Data on water quality are likely to be collected by the Ministry of Environment or the Ministry of Water, who can start compiling data for the five core parameters at existing sampling stations. Field measurement kits are readily available for the monitoring of the core water quality parameters.

As available resources and capacity increase, more sampling stations can be added to increase the frequency of sampling. Additional parameters relating to particular concerns in a given water body can be added to the indicator.

Although limited to only a few water quality parameters and larger rivers and lakes, satellite-based remote sensing could support monitoring for indicator 6.3.2 in areas lacking traditional, ground-based water quality monitoring.

Data on 6.3.2 feeds directly into the monitoring of 6.6.1.

The monitoring of wastewater from hazardous industries and of ambient water quality enables stricter enforcement of pollution laws and discharge permits. If a country lacks national targets for water quality parameters, the monitoring of 6.3.2 is a good opportunity to develop these.

The monitoring of wastewater from hazardous industries and of ambient water quality enables stricter enforcement of pollution laws and discharge permits. If a country lacks national targets for water quality parameters, the monitoring of 6.3.2 is a good opportunity to develop these.

The United Nations Environment Programme compiles country data at the global level and supports countries in their monitoring efforts.