4.2 Biological assessment of river quality

Page Last modified 20 Apr 2016, 02:32 PM

4.2 Biological assessment of river quality

Almost all aquatic plant or animal communities, be it micro- or macroscopic, may provide information on the quality of its environment. The community most commonly used in river quality investigations is that of the larger readily visible invertebrate animals colonizing the substrata of all rivers; such animals are collectively referred to as macroinvertebrates of which the main constituents are young aquatic stages of insects. Within this bottom dwelling community the sensitivity and tolerance to pollution of the various constituents vary considerably from species to species. Some species are, for example, very sensitive to reductions in dissolved oxygen and will not be found in areas where oxygen levels are not consistently high. A characteristic feature of polluted environments is a reduction in overall community diversity and an increase in the density of tolerant species. The composition of a macroinvertebrate community at any point in a river therefore reflects the average water quality at that particular point. For this reason macroinvertebrates are widely used in the assessment of river quality.

In the European countries there is a long tradition for assessment of river quality on the basis of macroinvertebrate studies. However, these assessments have primarily been made by local organizations responsible for managing and monitoring specific rivers. In some countries these activities have developed into national surveys of the biological quality of the main rivers (Table 4.2.1). These national surveys are generally based on the results collected by local authorities in accordance with harmonized and standardized procedures (eg. sampling methods, criteria for site selection, classification schemes, etc.). Most of the other countries do not have separate national monitoring programmes for biological assessment of river quality (Table 4.2.1). In some countries macroinvertebrate studies are, included in the general chemical river monitoring programme, macroinvertebrate investigations being, however, restricted to relatively few sampling sites.

Table 4.2.1: Biological assessment of river water quality

No national macroinvertebrate assessment programme (or no information) Macroinvertebrate assessment based on sampling sites included in the national chemical river monitoring programmes Special national surveys to assess the biological quality of rivers
Finland

Greece

Iceland

Austria AU-R1

Denmark DK-R1

France FR-R1

Ireland IE-R2

The Netherlands NL-R1

Norway NO-R2

Sweden SE-R2/SE-R3

Austria

Belgium BE-R2/R8

Germany DE-R2

Luxembourg LU-R2

(Portugal)

Spain ES-R2

United Kingdom UK-R3

National surveys to assess the biological quality of rivers

The specific biological monitoring surveys are usually made in connection with national classification of river quality. Austria, Germany, Luxembourg, Ireland and the United Kingdom have assessed rivers quality at two to five year intervals since the 1970s, while Belgium and Spain initiated similar activities in the 1980s. In 1992, the Netherlands added a biological subprogramme to their inland water monitoring programme MWTL and since 1989 Denmark has annually been collecting all the biological classification grades from the Danish counties. In Portugal, biological assessment (Saprobic system) is undertaken in a number of separate investigations.

Table 4.2.2: National river monitoring programmes based on assessment of biological river quality.

Code Name Variables Period Sampling frequency in year of survey Geographical coverage Reporting
AU- Austria
Gewässergüte der Fliessgewässer Österreichs
Saprobic system

MINVERT

Since 1968

Every two years

  Nation-wide Report & maps every 2 year
BE-

R2

Belgium
Biological assessment of the quality of rivers in the Flanders region of Belgium
MINVERT

Belgium

Biotic Index

 

Since 1989

Not every year

1/yr Flanders part of Belgium

900 sites

Report

annually

BE-

R8

Belgium
Biological assessment of the quality of rivers in the Walloon region of Belgium
MINVERT
Belgium
Biotic Index,
Phytoplankton,
Macrophytes
Since 1980

Every three years

1/yr Walloon region of Belgium

200+150 sites

Report

& maps every 3 years

DK

-

R4

Denmark
Inventory of biological assessment of river quality
MINVERT
The method and classification schemes used by Danish counties are not fully comparable
Since 1989

Annual collection of the results of biological classification of rivers

1-2/yr No standard network

Totally 10,000 sampling sites per year

Reports annually
DE

-

R2

Germany
Water quality maps of the quality of flowing waters
Saprobic system
MINVERT
MiFLORA
MIFAUNA
Since 1976
Every 5 years
1976, 1980, 1985 & 1990
  National all main flowing waters Maps
IE

-

R2

Ireland
Biological assessment of river quality
MINVERT
MAPHYT
ALGAE
siltation
Since 1971

-1993 : every 4 years

1994- : every 3 years

1/yr in June-September National expanding from 2,000 km in 1971 to 7,000 km in 1981 and 12,700 km in 1990
approx. 3000 sites in 1200 rivers
Tables maps every 3 years
LU

-

R2

Luxembourg
Biological assessment of river quality
Belgium Biotic Index

MINVERT and occasionally plankton and macrophytes

Since 1972

Every 3 to 5 years

Heavily polluted rivers are controlled every year

  National
Sampling are taken in the main rivers and their principal affluent especially those with fishery interests
 
ES
-
R2
Spain
Biological assessment of river quality
BMWP

Modified biotic index

Since 1980

Every 3 to 5 years

4/yr Nation-wide

847 sampling sites

Reports and maps
UK

-

R3

United Kingdom
Biological classification of rivers and canals
MINVERT Since the early 1970s

Every 5 years

Two or three annual samples England & Wales
40,000 km of rivers and canals, approx. 7,000 sites
Scotland
11,000 km of rivers, 976 sampling sites
Northern Ireland
2,500 km of rivers approx. 290 sites
Reports

MINVERT: studies of macroinvertebrate community; MiFAUNA: microfauna; MiFLORA: microflora; MAPHYT: macrophyte

The established monitoring networks generally include numerous sampling sites. The UK network and the Irish network, for instance, include around 10,000 and 3,000 sampling sites, respectively. Sites are generally located in all main rivers and reflect the full range of quality conditions of each particular river. The sampling methods used differ and sampling frequency varies among the countries (Table 4.2.2). Additional information on the various methods used for river quality classification can be found in Newman (1988), who made a more comprehensive evaluation of the different classification schemes used in the EU Member States.

In the UK and Germany local authorities, ie. the National River Authority regions and River Purification Boards in the UK, and the Länder in Germany, do the actual sampling and analysis, and special, organised task forces collect the summary results from the local organizations for national evaluation and reporting. In Ireland, by contrast, the biological assessment monitoring programme is carried out by one institution, namely the Environmental Protection Agency. The results are generally published in the form of reports including tables listing the length of rivers assigned to the various grades and river quality maps.


Biological assessment in connection with general national river monitoring programmes

The biological assessment in connection with general river monitoring programmes (eg. AU-R1, DK-R1, FR-R1, and SE-R2/R3) includes one or two annual investigations of macroinvertebrate communities at fixed sampling sites (Table 4.2.3). Additionally, some monitoring programmes include studies of periphyton, macrophytes and fish.

Table 4.2.3: Biological assessment of river quality in connection with general national river monitoring programmes.

Code Name Variables Period of operation and sampling frequency (SF) Geographical coverage
AU-R1 Austria
Ordinance on Water Quality Monitoring (rivers)
Saprobic index
Macroinvertebrates,
Phytobenthos,
Since 1991 Nation-wide
244 sampling sites
DK-R1 Denmark
Nation-wide monitoring programme
Monitoring of streams
Macroinvertebrates
Phytobenthos
since 1989
SF: 2/yr
Nation-wide
261 sampling sites
FR-R1 France
National basin network
Invertebrates
Fish
Since
SF:
Nation-wide
1082 sampling sites
NL-R1 The Netherlands
National surface water monitoring programme (MWTL), biological part
Macroinvertebrates, Fish, Phytoplankton, zooplankton, macrophytes Since 1992
SF: 1-13/yr, annually or in a four year cycle
Nation-wide
15 routine sampling sites
SE-

R2

Sweden
National time series reference streams
Macroinvertebrates
Periphyton
Since 1993
SF: 1/yr
35 streams
SE- R3 National intensive time series reference streams Macroinvertebrates
Periphyton
Fish
Macrophytes
Since 1994
SF: 1/yr except macrophytes every 3 year
15 streams

lijn.gif (900 bytes)

up.gif (859 bytes)
left.gif (869 bytes) right.gif (869 bytes)
</head0
European Environment Agency (EEA)
Kongens Nytorv 6
1050 Copenhagen K
Denmark
Phone: +45 3336 7100