1. Sustainable Development Goal for Water: Indicator 6.3.2
Stuart Warner
UNEP GEMS/Water

2. Proportion of wastewater safely treated
Target 6.3
By 2030, improve water quality by reducing pollution, eliminating dumping and minimizing release of hazardous chemicals and materials, halving the proportion of untreated wastewater and substantially increasing recycling and safe reuse globally
Indicator 6.3.1
Proportion of wastewater safely treated
Indicator 6.3.2
Proportion of bodies of water with good ambient water quality
The indicator allows countries to assess the outcomes and impacts of water quality management measures

3. Proportion of wastewater safely treated
Target 6.3
By 2030, improve water quality by reducing pollution, eliminating dumping and minimizing release of hazardous chemicals and materials, halving the proportion of untreated wastewater and substantially increasing recycling and safe reuse globally
Indicator 6.3.1
Proportion of wastewater safely treated
Indicator 6.3.2
Proportion of bodies of water with good ambient water quality
The indicator allows countries to assess the outcomes and impacts of water quality management measures

4. Rivers, lakes and groundwater bodies
What do we mean by “ambient” waters?
Rivers, lakes and groundwater bodies
Ambient water provides:
A source of drinking water
Fisheries for food
Recreational opportunities
Irrigation for crops
Many other ecosystem services

5. What is “good” ambient water quality?
Water quality that does not damage ecosystem function or present a risk to human health
not severely impacted by human activities
sewage
wastewater discharges
agricultural run-off
supports a balanced ecosystem, including fisheries
safe for recreational activities, such as water contact activities

6. General principles of indicator 6.3.2
“Good quality” is assessed in relation to target values for key ambient water quality parameters
Countries set their own targets for good ambient water quality
For baseline global reporting, five water quality parameters (DO, EC, DIN/TN, TP, FCB) have been recommended
Monitoring data for selected parameters at each station on a waterbody are compared to target values to produce an index value
Data are aggregated by temporally, and by waterbody to produce the country level indicator value

7. Choice of water quality parameters
Dissolved oxygen: essential for aquatic organisms, low values may indicate organic matter pollution
Nitrogen (DIN/TN): an essential aquatic nutrient but high concentrations often result from agricultural run-off or waste inputs
Phosphorus (DIP/TP): an essential aquatic nutrient but high concentrations, often associated with agricultural run-off and sewage effluents, lead to eutrophication
Electrical conductivity: a measure of dissolved substances, high values may suggest wastewater inputs
Faecal coliform bacteria or E. coli: indicate presence of human and animal faecal matter and a potential risk for human
Health
Depending on national capacities and requirements, additional parameters can be included, and spatial and temporal intensity can be increased
Internationally recognized standard methods should be used with appropriate quality assurance

8. Step by step approach Categorize and select representative waterbodies
Select parameters and target values (baseline of five core parameters)
Carry out monitoring and/or use existing monitoring data
Past and present water quality monitoring data may already be available for many countries through the GEMS/Water Global Water Quality Information System GEMStat
Calculate indicator at national level
Use of GEMStat as an existing data portal and web services infrastructure for the global reporting

9. Examples of monitoring station locations on a single waterbody

10. Setting Target Values
Different target values may be needed for different types of waterbody
Natural fluctuations in parameters, e.g. seasonally driven, need to be considered before setting the target values
Countries set their own target values – published examples can be used as a guideline
Potential uses of the waterbodies may guide the selection of target values

11. Examples of published target values for core water quality parameters
Unit
Target type
Remarks
Reference
Dissolved Oxygen 6
mg/l
Lower*
if average water temperatures >20°C
Carr & Rickwood (2008)9
9.5
If average water temperatures ≤20°C
Electrical Conductivity
500
µS/cm
Upper*
Dissolved Inorganic Nitrogen 50
as NO3- in drinking water
WHO (2011)10 11
as NO3-N in drinking water 3
as NO2- in drinking water
as ammonia, toxicity to fish
WRC (2016)11
Total Phosphorus
0.2
Class II “Good” quality
OECD (2008)12
Faecal Coliform Bacteria
2000
No. per 100 ml
Class II Suitable for treatment for drinking water and for recreational use
* Target types are designated as “upper”, meaning the value should not be exceeded, or “lower”, meaning the value should not fall below

12. Suggested compliance levels for different standards of water quality
Quality Designation
Percentage compliance or index value
Description
Excellent
95-100
All measurements are within objectives virtually all of the time
Good
80-94
Conditions rarely depart from natural or desirable levels
Fair
65-79
Conditions sometimes depart from natural or desirable levels
Marginal
45-64
Conditions often depart from natural or desirable levels
Poor
0-44
Conditions usually depart from natural or desirable levels
Good water quality requires compliance of 80% or higher with target values

13. Example calculation of the Indicator
In the following example, a country has two waterbodies (it’s very small) with a total of five monitoring stations (2 at one and 3 the other) are we’re using the five core parameters to classify.
Sampling values at each station are compared with their specific target values
The compliance for each parameter is averaged over the accounting period
The percentage compliance for all five parameters is averaged to give a station-level percentage and an indication of station-level water quality
All stations in a waterbody are then averaged and finally all waterbodies in the country are averaged
Result is an indicator value for the entire country

14. Parameter meets target value?
Classification of each waterbody
Parameter meets target value?
Select water quality parameters according to intended step of monitoring ladder
Select target values for each water quality parameter
For each station of waterbody: carry out measurements or gather data and compare with target values
Yes No
Score = 1
Score = 0
Scores for Waterbody 1 over three years
Station
Date
DO Score
EC Score
TN Score
TP Score
FCB Score
001 1
002

15. Aggregation of station data to give Indicator 6.3.2
Aggregation Station 001
Aggregation Station 002
Site
Date
DO Score
EC Score
TN Score
TP Score
FCB Score
001 1
Temporal aggregation
66.6%
33.3%
100%
Station level aggregation
Site
Date
DO Score
EC Score
TN Score
TP Score
FCB Score
002 1
Temporal aggregation
33.3%
66.6%
100%
Station level aggregation
59.9%
Aggregation to SDG Indicator
Aggregation
Waterbody 1
Waterbody 2
001
002
003
Station-level
66.6%
59.9%
84.5%
75.0%
82.2%
Waterbody-level
63.3%
= Marginal
= 0
80.6%
= Good
= 1
Country-level
50%
waterbodies are of good ambient water quality

16. Proximity to Target
The PTT scores are scaled to the range between 0 and 100
100 indicates the target is met, and decreasing scores indicate an increasing distance from the target
Calculated over the accounting period e.g. 3 years
If the target is the upper threshold as for electrical conductivity
If the target is the lower threshold as for dissolved oxygen
If the target is between and upper and lower threshold

17. Proximity to Target Waterbody 1 Waterbody 2 Station 1 Station 2DO
75.24
75.54
100
85.52
65.52 EC
80.05 95 TN
62.45
75.94
85.54
85.25 TP
71.02
85.49
84.54
74.65
FCB
95.65
65.54
75.25
Station level
80.872
76.512
86.17
81.134
Waterbody level
78.69 = Fair
= Good
National level
50 %

18. Topics for consideration
Setting of country-specific target values
Existence of, and access to, monitoring data on which to base target values
Monitoring site selection and spatial coverage
Capacity to measure core parameters in ambient waters
Quality assurance of monitoring data
Field operations, lab operations and data handling
Data storage, indicator calculation and reporting mechanisms

19. Thank you for listening
Stuart Warner
UNEP GEMS/Water Capacity Development Centre
Training in best practice in all aspects of water quality
monitoring activities is available through
UNEP GEMS/Water