quality accounts. outline why quality accountswhy quality accounts structure of quality...
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Quality AccountsQuality Accounts
OutlineOutline
• Why Quality AccountsWhy Quality Accounts• Structure of Quality AccountsStructure of Quality Accounts
• AquifersAquifers• RiversRivers
• How to define quality classes?How to define quality classes?• Several country examplesSeveral country examples
• IssuesIssues• AggregationAggregation• MeasurementMeasurement
Why quality accounts?Why quality accounts?• Quality accounts describe the quality of water resources at Quality accounts describe the quality of water resources at
the beginning and end of the accounting period in terms of the beginning and end of the accounting period in terms of chemical, physical and biological characteristicschemical, physical and biological characteristics
• Important becauseImportant because• Quality limits water availability for certain purposesQuality limits water availability for certain purposes• It is a first step towards ecosystem accounting and its It is a first step towards ecosystem accounting and its
variantsvariantsBUT BUT
• Still experimental (few country experiences; little or no Still experimental (few country experiences; little or no standardization)standardization)
• Link with pressures due to human activities is not directLink with pressures due to human activities is not direct
Quality of what?Quality of what?• Quality of water bodies, NOT waterbeds / riparian Quality of water bodies, NOT waterbeds / riparian
zonezone• Water body : “mass of water distinct from other Water body : “mass of water distinct from other
masses of water”masses of water”• Examples: rivers, lakes, aquifers …Examples: rivers, lakes, aquifers …
Structure of quality accountsStructure of quality accounts
QUALITY CLASSESQUALITY CLASSES Physical Physical unitsunits
Quality 1Quality 1 Quality 2Quality 2 -- Quality nQuality n TotalTotal
Opening Opening stocksstocks
Changes in Changes in stocksstocks
Closing Closing stocksstocks
Source: SEEAW
Aquifers: AustraliaAquifers: Australia
Source: Water Account for Australia – 1993-94 to 1996-97 - Australian Bureau of Statistics, May 2000.
FreshFresh<500 mg/l<500 mg/l
MarginalMarginal500-1500 mg/l500-1500 mg/l
BrackishBrackish1500-5000 mg/l1500-5000 mg/l
SalineSaline>5000 mg/l>5000 mg/l
TotalTotal
19951995 477.5477.5 339.2339.2 123.3123.3 32.332.3 972.3972.3
1998 1998 (incomplete)(incomplete)
(39.1)(39.1) (566.6)(566.6) (141.1)(141.1) (n.a.)(n.a.) (746.8)(746.8)
Groundwater quality in Victorian provinces (in million m3)
Based on sustainable yield as a proxy, NOT volume of storage
Rivers: from point to monitoringRivers: from point to monitoring
State A
State B0100%100%
+0%13.5%13.5%
-19%37.5%56.2%
+31%50.0%18.8%
-13%0.0%12.5%
ChangeState B
State A
Quality class
Are these statistics relevant?
RiversRivers• Monitoring of points & generalisation to water systems Monitoring of points & generalisation to water systems
• Particular difficulty with water courses: how to account for Particular difficulty with water courses: how to account for their relative size?their relative size?
• Runoff is measured at the lowest point of a basin – the Runoff is measured at the lowest point of a basin – the quality varies along the streamquality varies along the stream
• The mere length confuses large rivers and small streamsThe mere length confuses large rivers and small streams
• Statistics of points make sense only when the monitoring Statistics of points make sense only when the monitoring system is dense – rarely the casesystem is dense – rarely the case
Stretches / ReachesStretches / Reaches
Reach or stretch: Reach or stretch: a portion of a stream or river, as from one a portion of a stream or river, as from one turn to another, turn to another, supposedly having constant characteristicssupposedly having constant characteristics any distance between 2 monitoring pointsany distance between 2 monitoring points
River group
Small
Medium
Large
Quality
Class1
Class2
Class3
†…
„
ƒ
‚
ˆ
‡
Accounting unit: SRU (1)Accounting unit: SRU (1)
• River reaches as basic accounting units for riversRiver reaches as basic accounting units for rivers• Importance is best measured by length and dischargeImportance is best measured by length and discharge• Best candidate is SRU (Best candidate is SRU (standard river unit) =standard river unit) =
reach length reach length discharge in m discharge in m3 3 ss-1-1
• Large and small rivers can be aggregated when measured Large and small rivers can be aggregated when measured in SRUsin SRUs
• Can be classified or weighted with quality indexesCan be classified or weighted with quality indexes• Results comparables from basin to basinResults comparables from basin to basin• Robust and easy to computeRobust and easy to compute
Accounting Unit: SRU (2)Accounting Unit: SRU (2)
X
Fast, small
Slow, medium
Large river Qi
Qj
Qk
Li
X
XLk
Lj
= a SRU
= b SRU
= c SRU
Flow Length
SummarySummary
For compiling quality accounts we need: For compiling quality accounts we need:
• SRU value for each river reach for all riversSRU value for each river reach for all rivers
• We need to assign a quality for each reach We need to assign a quality for each reach for all riversfor all rivers
Accounting Unit: SRU (2)Accounting Unit: SRU (2)
X
Fast, small
Slow, medium
Large river Qi
Qj
Qk
Li
X
XLk
Lj
= 4 SRU
Q1
= 0.5 SRU
Q2
= 1.5 SRU
Q2
Flow Length
Structure of quality accountsStructure of quality accounts
QUALITY CLASSESQUALITY CLASSES Physical Physical unitsunits
Quality 1Quality 1 Quality 2Quality 2 -- Quality nQuality n TotalTotal
Opening Opening stocksstocks
44 22
Changes in Changes in stocksstocks
Closing Closing stocksstocks
Source: SEEAW
Ways of assessing water qualityWays of assessing water quality
• According to disturbances/perturbations to According to disturbances/perturbations to functionsfunctions
• Total hydraulic and osmotic power of river Total hydraulic and osmotic power of river basinsbasins
• Health of ecosystem approach (resilience)Health of ecosystem approach (resilience)
Defining quality classesDefining quality classes
• Normative values for “determinands” (parameters)Normative values for “determinands” (parameters)• Physical: temperature, colourPhysical: temperature, colour• Chemical: pH, Chemical: pH, NH4+NH4+ … …• Biological: bacteria, flora, fish … Biological: bacteria, flora, fish … • Etc..Etc..
• Allowable deviations from reference conditionsAllowable deviations from reference conditions• European Water Framework DirectiveEuropean Water Framework Directive
Example: Malaysia (1)Example: Malaysia (1)
WQI = 0.22*SI DO + 0.19*SI BOD + 0.16*SI COD WQI = 0.22*SI DO + 0.19*SI BOD + 0.16*SI COD + 0.15*SI AN + 0.16*SI SS + 0.12*SI pH+ 0.15*SI AN + 0.16*SI SS + 0.12*SI pH
where SI is the subindex of each parameter.where SI is the subindex of each parameter.DO - Dissolved OxygenDO - Dissolved OxygenBOD - Biological Oxygen DemandBOD - Biological Oxygen DemandCOD - Chemical Oxygen DemandCOD - Chemical Oxygen DemandAN - Ammoniacal NitrogenAN - Ammoniacal NitrogenSS - Suspended SolidSS - Suspended SolidpH - Acidity/AlkalinitypH - Acidity/Alkalinity
Example: Malaysia (2)Example: Malaysia (2)Usage 10 20 30 40 50 60 70 80 90 100 WQI
General Very Polluted Slightly Polluted Clean
Water Class
V IV III II I
Public Water Supply
Not Acceptable DoubtfulNecessary Treatment Becoming
more Expensive
Minor Purific
Required
Purification not Necessary
Recreation
Not AcceptableObvious Pollution
Appearing
Only for Boating
Doubtful for Water Contact
Becoming Polluted Still Acceptable Need Bacteria Count
Acceptable for all Sports
Fish, Shellfish and Wildlife
Not AcceptableCoarse
Fish OnlyHandy
Fish Only
Doubtful for
Sensitive Fish
Marginal for Trout
Acceptable for all Fish
Navigation
Not AcceptableObvious Pollution
AppearingAcceptable
Treated water Transportation
Not Acceptabl
eAcceptable
10 20 30 40 50 60 70 80 90 100 WQI
Example: France (1)Example: France (1)
• SEQ-eau• Use-oriented
Recognizes: drinking water, leisure, irrigation, livestock watering, aquaculture aquatic life
• Based on 15 suitability indicators• Computed from 135 determinants• Matrices:
• determinants X indicators (computed from)• uses X indicators (significant for)• determinants X classes (threshold values)
Source: Presentation User-Producer Conference by R. Lalement
Example: France (2)Example: France (2)
Example: France (3)Example: France (3)
Example: France (4)Example: France (4)
• Results in • a class of suitability for each use • an index (and class) for overall quality
• For each indicator, the worst determinant wins• For each use, the worst indicator wins• For each determinant, apply the percentile 90 rule to
multiple samples (not the average)[this is called “Rule of the worst”]• ... an in depth assessment for uses, • but little ecology : independent of « ecotype »
France: Monitoring Costs (5)France: Monitoring Costs (5)• The estimated cost of the surveillance monitoring programme is
• 77 M€ for rivers and • 8M€ for lakes
• for a management plan, or
• 50 k€ for rivers • 40 k€ for lakes
• per site for a management plan, or
• 150 €/km2 (rivers and lakes), or • 150 €/km (rivers).
Example: CanadaExample: Canada
S = scope, number of failed determinands/total
F = frequency, number of failed tests/total
E = excursion, target value/observed value
Results: French Quality AccountsResults: French Quality Accounts
Example:France 1992-1994
Results: organic matter indicator in SRU*1000
ISSUESISSUES
• Choice of determinandsChoice of determinands
• Classification of usesClassification of uses
• Assessment: Rule of worstAssessment: Rule of worst
• Temporal issuesTemporal issues
• Aggregation over space (indicators)Aggregation over space (indicators)
• Link with economic sphereLink with economic sphere
Choice of determinandsChoice of determinands
Determinand group
Number of determinands
Total
of which: Specific to
Canada
of which: Specific to
France
of which: Specific to
South Africa
of which: Common
determinands
Environmental 10 1 1 1 6
Gases dissolved 5 2 1 1
Metals (and metalloids) 24 3 2 1 9
Nutrients 5 1 1 1
Pesticides 68 22 23 6 4
Radioactivity 26 26
Salinity 14 1 3 4
Toxics (n-metal, n-pesticides) 104 36 38 3 2
• Country and context dependentCountry and context dependent• Based on functions or usesBased on functions or uses
Classification of usesClassification of uses
• No standardized classification of uses or No standardized classification of uses or functionsfunctions
• Different uses for different type of water Different uses for different type of water bodies? (case of France)bodies? (case of France)
• Different uses per water body? (USA)Different uses per water body? (USA)
• How to deal with multiple use?How to deal with multiple use?
• Choose the most stringent use? (AUS)Choose the most stringent use? (AUS)
Assessment : Rule of the worstAssessment : Rule of the worst
• ““One out, all out”One out, all out”• Reason: assure equal weight to all parametersReason: assure equal weight to all parameters
• Applicable at level of determinands, indicators Applicable at level of determinands, indicators or usesor uses
• Problem:Problem:• Extreme values; seasonal variationsExtreme values; seasonal variations• Improvement of monitoring leads to increased Improvement of monitoring leads to increased
probability of finding bad statusprobability of finding bad status
Rule of the worst: ApplicationRule of the worst: Application
Reach "2005" "2006" RofW_05QC 05 RofW_06QC_06 SRU1Det 1 Det 2 Q Det 1Det 2 Q
Station1 25 60 12 20 60 60 20 12 1 60 3 5002 25 60 60 20 60 60 20 60 3 60 3 5003 25 60 60 20 60 60 20 60 3 60 3 5004 25 60 60 20 60 60 20 60 3 60 3 500
QC1 QC2 QC3 QC4 QC5Opening stocks 500 0 1500 0 0Closing stocks 0 0 2000 0 0Changes in stocks -500 0 500 0 0
Aggregation: space (1)Aggregation: space (1)
• Which rivers to include?Which rivers to include?
• Scale determines outcomeScale determines outcome
• River basinRiver basin
• Weighted average indicatorWeighted average indicator
• HotspotsHotspots
• Pattern indexPattern index
Aggregation: space (2)Aggregation: space (2)
• River Quality Global Index (RQGI)Quality Global Index (RQGI)
• Aggregates over river basinAggregates over river basin
• Weighted average of SRU according to quality classWeighted average of SRU according to quality class
• Scale 0-10Scale 0-10
• nn is number of classes is number of classes
Aggregation: space (3)Aggregation: space (3)
• Pattern indexPattern index
• Measures the variability in space in quality Measures the variability in space in quality of the River Basinof the River Basin
• Able to distinguish “hotspots”Able to distinguish “hotspots”
Temporal issuesTemporal issues
• How to reflect seasonal variations in the quality How to reflect seasonal variations in the quality accounts?accounts?
• What to do with inter-annual variations (wet What to do with inter-annual variations (wet years..)years..)• Actual SRU or averages?Actual SRU or averages?
• How to deal with sudden eventsHow to deal with sudden events• Frequency of monitoringFrequency of monitoring
SEEAW advocates compilation of Quarterly SEEAW advocates compilation of Quarterly AccountsAccounts
Link with economic sphere (1)Link with economic sphere (1)
• Water quality accountsWater quality accounts• Ideal is to measure efficiency of water quality Ideal is to measure efficiency of water quality
management programmes at basin levelmanagement programmes at basin level• BUT: changes in water quality can have different causes BUT: changes in water quality can have different causes
Water quality t1 = f(Water quality t0, ∆(uncontrolled Water quality t1 = f(Water quality t0, ∆(uncontrolled events), ∆(abstractions), ∆(emissions), ∆(expenditure))events), ∆(abstractions), ∆(emissions), ∆(expenditure))
• f() = unknownf() = unknown• Therefore…….Therefore…….
Link with economic sphere (2)Link with economic sphere (2)QC1QC1 QC2QC2 -- QCnQCn TotalTotal
Opening stockOpening stock
Changes due Changes due to economic to economic causescauses
Discharge of Discharge of waste waterwaste water
AbstractionAbstraction
ReturnsReturns
Changes due Changes due to natural to natural causescauses
accidentsaccidents
Closing stockClosing stock
QuestionsQuestions
• Data availability? Data availability? • Frequency?Frequency?• Distribution of monitoring stations?Distribution of monitoring stations?• Are flows and quality measured Are flows and quality measured
simultaneously?simultaneously?• Which determinands are measured?Which determinands are measured?• Economic data per river basin?Economic data per river basin?
• Are different uses distinguished?Are different uses distinguished?• Experience in compilation?Experience in compilation?