The biological monitoring working party (BMWP) is a procedure for measuring water quality

Water quality

Water quality is the physical, chemical and biological characteristics of water. It is a measure of the condition of water relative to the requirements of one or more biotic species and or to any human need or purpose. It is most frequently used by reference to a set of standards against which...

 using species of macroinvertebrates as biological indicators.

The method is based on the principle that different aquatic

Aquatic animal

An aquatic animal is an animal, either vertebrate or invertebrate, which lives in water for most or all of its life. It may breathe air or extract its oxygen from that dissolved in water through specialised organs called gills, or directly through its skin. Natural environments and the animals that...

 invertebrate

Invertebrate

An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...

s have different tolerances to pollutant

Pollutant

A pollutant is a waste material that pollutes air, water or soil, and is the cause of pollution.Three factors determine the severity of a pollutant: its chemical nature, its concentration and its persistence. Some pollutants are biodegradable and therefore will not persist in the environment in the...

s. The presence of mayflies

Mayfly

Mayflies are insects which belong to the Order Ephemeroptera . They have been placed into an ancient group of insects termed the Palaeoptera, which also contains dragonflies and damselflies...

 or stoneflies for instance indicate the cleanest waterways and are given a tolerance score of 10. The lowest scoring invertebrates are worms (Oligochaeta) which score 1. The number of different macroinvertebrates is also an important factor, because a better water quality is assumed to result in a higher diversity.

Kick sampling, where a net is placed downstream from the sampler and the river bed is agitated with the foot for a given period of time (the standard is 3 minutes), is employed. Any macroinvertebrates caught in the net are stored and preserved with an alcohol solution, and identified to the family

Family (biology)

In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 level, this can be done with the live organisms as well.

The BMWP score equals the sum of the tolerance scores of all macroinvertebrate families in the sample. A higher BMWP score is considered to reflect a better water quality. Alternatively, also the Average Score Per Taxon (ASPT) score is calculated. The ASPT equals the average of the tolerance scores of all macroinvertebrate families found, and ranges from 0 to 10. The main difference between both indices is that ASPT does not depend on the family richness. Once BMWP and ASPT are calculated, the Lincoln Quality Index (LQI) is used to asses the water quality in the Anglian Water Authority area.

Other indices that can be used to asses water quality are the Chandler Score, the Trent Biotic Index and the Rapid Bioassessment Protocols.

Scoring table

BMWP Score table

Group	Families	Score
Mayflies, Stoneflies, Riverbug, Caddisflies or Sedgeflies	Siphlonuridae, Heptageniidae Heptageniidae Heptageniidae is a family of mayflies with over 500 described species mainly distributed in the Holarctic, Oriental, and Afrotropical regions, and also present in the Central American Tropics and extreme northern South America. These are generally rather small mayflies with two long tails... , Leptophlebiidae Leptophlebiidae Leptophlebiidae is a family belonging to the Ephemeropterans that are commonly known as the prong-gilled mayflies or leptophlebiids. In North America they occur with about 70 species from 9 genera in freshwater streams and lakes; in Europe they are somewhat less diverse. Globally, this family is... , Ephemerellidae Ephemerellidae Ephemerellidae are known as the Spiny Crawler Mayflies. They are a family of the order Ephemeroptera. There are 8 genera consisting of a total 90 species . They are distributed throughout North America as well as the UK. Their habitat is lotic-erosional, they are found in all sizes of flowing... , Potamanthidae, Ephemeridae Ephemeridae Ephemeridae is a family of mayflies with about 150 described species found throughout the world except Australia and Oceania. These are generally quite large mayflies with either two or three very long tails... , Taeniopterygidae Taeniopterygidae Taeniopterygidae are a family of stone flies with about 80 described extant species. They are commonly called willowflies or winter stoneflies and have a holarctic distribution.Adults are usually smaller than 15 mm.-Species:Sources are , and... , Leuctridae, Capniidae Capniidae Capniidae, the small winter stoneflies, is a family of insects in the stonefly order . It constitutes one of the largest stonefly families, containing some 300 species distributed throughout the Holarctic... , Perlodidae Perlodidae Perlodidae, also known as the Perlodid stoneflies, stripetails, or springflies, are a family of stoneflies.-Natural history:The family Perlodidae is composed of approximately 30 genera and over 103 species, with the fossil records that extends at least since Triassic. The majority of Perlodid... , Perlidae Perlidae Perlidae is a family of stoneflies.There are 15 genera with a total of 72 species . The majority of the Perlidae are found in the East. The life cycle length can be between 1 and 3 years. They adults emerge in the summertime. The adults are very active and known to be attracted to light sources... , Chloroperlidae Chloroperlidae Chloroperlidae is a family of stoneflies commonly known as green stoneflies. There are more than 180 species in the family. They appear in colors of green and yellow.... , Aphelocheridae, Phryganeidae, Molannidae, Beraeidae, Odontoceridae, Leptoceridae, Goeridae, Lepidostomatidae, Brachycentridae, Sericostomatidae	10
Crayfish Crayfish Crayfish, crawfish, or crawdads – members of the superfamilies Astacoidea and Parastacoidea – are freshwater crustaceans resembling small lobsters, to which they are related... , Dragonflies	Astacidae Astacidae The family Astacidae comprises the freshwater crayfish native to Europe and western North America. It is made up of three genera. Pacifastacus is found on the Pacific coast of the United States and British Columbia and includes the signal crayfish and the Shasta crayfish... , Lestidae Lestidae Lestidae is a rather small family of cosmopolitan, large-sized, slender damselflies. They are of the order of the dragonflies and are commonly known as "Spreadwings." There are two subfamilies in Lestdae. The first subfamily is Lestinae. Damselflies in Lestinae rest with their wings partly open... , Agriidae, Gomphidae Gomphidae Gomphidae is an Odonata family that contains about 90 genera and 900 species. They are commonly referred to as clubtail dragonflies. The name refers to the clublike widening of the end of the abdomen... , Cordulegasteridae, Aeshnidae Aeshnidae The hawkers include the largest dragonflies found in North America and Europe, and are among the largest of the dragonflies on the planet... , Corduliidae Corduliidae The insect family Corduliidae contains the emerald dragonflies or green-eyed skimmers. These dragonflies are usually black or dark brown with areas of metallic green or yellow, and most of them have large, emerald-green eyes... , Libellulidae Libellulidae The skimmers or perchers and their relatives form the Libellulidae, the largest dragonfly family in the world. It is sometimes considered to contain the Corduliidae as the subfamily Corduliinae and the Macromiidae as the subfamily Macromiinae. Even if these are excluded , there still remains a...	8
Mayflies, Stoneflies, Caddisflies or Sedge flies	Caenidae Caenidae Caenidae, or the Small Squaregill Mayflies, is a family of insects consisting of 4 genera comprising 26 individual species. They are found throughout North America in lotic, depostional environments, and they are sprawlers. Caenids occur in quiet and even stagnant water and are often overlooked... , Nemouridae Nemouridae Nemouridae is a family of stoneflies. This is one of the largest stonefly families with more than 600 described species with a mainly Holarctic distribution. Members of this family are commonly known as spring stoneflies or brown stoneflies... , Rhyacophilidae Rhyacophilidae Rhyacophilidae is a family in the insect order of Trichoptera. Larvae of this family are free living and most species are predacious. The largest genus is Rhyacophila, with near 500 species distributed throughout the Northern Hemisphere.... , Polycentropodidae Polycentropodidae Polycentropodidae is a family level taxon consisting of trumpet-net and tube-making caddisflies.... , Limnephilidae Limnephilidae Limnephilidae is a family of caddisflies with about 100 genera. They belong to the main lineage of case-constructing caddisflies, the Integripalpia or tube-case caddisflies. The Limnephilidae is one of the most species-rich Trichoptera families of northern temperate regions, but only a few are...	7
Snail Snail Snail is a common name applied to most of the members of the molluscan class Gastropoda that have coiled shells in the adult stage. When the word is used in its most general sense, it includes sea snails, land snails and freshwater snails. The word snail without any qualifier is however more often... s, Caddisflies or Sedge flies, Mussel Mussel The common name mussel is used for members of several families of clams or bivalvia mollusca, from saltwater and freshwater habitats. These groups have in common a shell whose outline is elongated and asymmetrical compared with other edible clams, which are often more or less rounded or oval.The... s, Gammarids, Dragonflies	Neritidae Neritidae Neritidae, common name the nerites, is a taxonomic family of small to medium-sized saltwater and freshwater snails which have a gill and a distinctive operculum, marine, brackish water and freshwater gastropod mollusks in the order Neritoida.... , Viviparidae Viviparidae Viviparidae, sometimes known as the river snails or mystery snails, are a family of large operculate freshwater snails, aquatic gastropod mollusks.... , Ancylidae Ancylidae Ancylini is a tribe of small, freshwater, air-breathing limpets, aquatic pulmonate gastropod mollusks in the family Planorbidae the ram's horn snails and their allies... , Hydroptilidae Hydroptilidae Hydroptilidae is a large family of caddisflies with a worldwide distribution. They are commonly known as microcaddisflies or purse-case caddisflies, in reference to two characteristic traits of this family: Hydroptilidae are much smaller than other caddisflies, rarely exceeding in length... , Unionidae Unionidae Unionidae is a family of freshwater mussels, the largest in the order Unionoida, the bivalve mollusks sometimes known as river mussels, naiads, or simply as unionids.The range of distribution for this family is world-wide... , Corophiidae Corophiidae Corophiidae is a family of amphipods, containing the following genera:*Americorophium Bousfield & Hoover, 1997*Anonychocheirus Moore & Myers, 1983*Apocorophium Bousfield & Hoover, 1997*Bathyphotis Stephensen, 1944*Cheirimedeia J. L... , Gammaridae Gammaridae Gammaridae is a family of amphipods. In North America they are included among the folk taxonomic category of "scuds", and otherwise gammarids is usually used as a common name.... , Platycnemididae Platycnemididae Platycnemididae are a family of damselfly called white-legged damselflies. It is sometimes known as Platycnemidae.This is a list of genera with the number of species in each.*Allocnemis — 2 species*Arabicnemis — 1 species... , Coenagrionidae Coenagrionidae The insect family Coenagrionidae is found in the order Odonata and the suborder Zygoptera. The Zygoptera are the damselflies, which although less known than the dragonflies, are no less common. There are more than 1100 species in this family, making it the largest damselfly family...	6
Bugs Hemiptera Hemiptera is an order of insects most often known as the true bugs , comprising around 50,000–80,000 species of cicadas, aphids, planthoppers, leafhoppers, shield bugs, and others... , Beetle Beetle Coleoptera is an order of insects commonly called beetles. The word "coleoptera" is from the Greek , koleos, "sheath"; and , pteron, "wing", thus "sheathed wing". Coleoptera contains more species than any other order, constituting almost 25% of all known life-forms... s, Caddisflies or Sedgeflies, Craneflies/Blackflies, Flatworm Flatworm The flatworms, known in scientific literature as Platyhelminthes or Plathelminthes are a phylum of relatively simple bilaterian, unsegmented, soft-bodied invertebrate animals... s	Mesoveliidae, Hydrometridae Hydrometridae Hydrometridae is a family of semi-aquatic insects, known as marsh treaders or water measurers. They have a characteristic elongated head and body which makes them resemble a yardstick for measuring the water surface.-Appearance:... , Gerridae, Nepidae Nepidae Nepidae is a family of insects in the order Hemiptera, suborder Heteroptera. They are commonly called waterscorpions for their superficial resemblance to a scorpion, which is due to the raptorial forelegs and the presence of a long slender process at the posterior end of the abdomen, simulating a... , Naucoridae Naucoridae Naucoridae is a small family of insects commonly known as the creeping water bugs. They are very similar in appearance and behavior to the giant water bugs , and also occur in ponds and other still waters. Occasionally, these insects can be found in damp places in a person's home, and are often... , Notonectidae Notonectidae Notonectidae is a cosmopolitan family of aquatic insects in the order Hemiptera, commonly called backswimmers because they swim upside down. They are all predators, up to nearly 2 cm in size. They are similar in appearance to Corixidae , but can be separated by differences in their... , Pleidae Pleidae Pleidae, the pygmy backswimmers, is a family of aquatic insects in the order Hemiptera . There are 37 species in three genera, distributed across most of the world, except the polar regions and remote oceanic islands.Pleidae belong to the Tripartita which contains the more advanced lineages of true... , Corixidae, Haliplidae, Hygrobiidae, Dytiscidae Dytiscidae Dytiscidae – based on the Greek dytikos , "able to dive" – are the predaceous diving beetles, a family of water beetles. They are about 25 mm long on average, though there is much variation between species. Dytiscus latissimus, the largest, can grow up to 45 mm long... , Gyrinidae, Hydrophilidae, Clambidae, Helodidae, Dryopidae, Elmidae, Chrysomelidae, Curculionidae Curculionidae Curculionidae is the family of the "true" weevils . It was formerly recognized in 1998 as the largest of any animal family, with over 40,000 species described worldwide at that time... , Hydropsychidae Hydropsychidae Hydropsychidae are a family-level taxon consisting of net-spinning caddisflies. Hydropsychids are common among much of the world's streams and a few species occupy the shorelines of freshwater lakes... , Tipulidae, Simuliidae, Planariidae Planariidae Planariidae is a family of Tricladida that inhabits the freshwater.The type genus is Planaria Müller, 1776.-Genera:Twelve genera of Planariidae are known:*Albiplanaria*Atrioplanaria*Crenobia*Galeocephala*Hymanella... , Dendrocoelida	5
Mayflies, Alderflies, Leech Leech Leeches are segmented worms that belong to the phylum Annelida and comprise the subclass Hirudinea. Like other oligochaetes such as earthworms, leeches share a clitellum and are hermaphrodites. Nevertheless, they differ from other oligochaetes in significant ways... es	Baetidae Baetidae Baetidae is a family of mayflies with about 900 described species distributed worldwide. These are among the smallest of mayflies, adults rarely exceeding 10 mm in length excluding the two long slender tails and sometimes much smaller, and members of the family are often referred to as small... , Sialidae, Piscicolidae	4
Snails, Cockle Cockle (bivalve) Cockle is the common name for a group of small, edible, saltwater clams, marine bivalve molluscs in the family Cardiidae.Various species of cockles live in sandy sheltered beaches throughout the world.... s, Leeches, Hog louse	Valvatidae Valvatidae Valvatidae, the valve snails, is a taxonomic family of very small freshwater snails with an operculum, aquatic gastropod mollusks.- Taxonomy :... , Hydrobiidae Hydrobiidae Hydrobiidae, common name mud snails, is a large cosmopolitan taxonomic family of very small freshwater snails and brackish water snails that have an operculum, aquatic gastropod mollusks in the clade Littorinimorpha.- Distribution :... , Lymnaeidae Lymnaeidae Lymnaeidae is a taxonomic family of small to large air-breathing freshwater snails, aquatic pulmonate gastropod mollusks, that belong to the clade Hygrophila.... , Physidae Physidae Physidae, common name bladder snails, are a monophyletic taxonomic family of small freshwater snails, aquatic pulmonate gastropod molluscs in the clade Hygrophila.... , Planorbidae Planorbidae Planorbidae, common name the ramshorn snails or ram's horn snails, is a family of air-breathing freshwater snails, aquatic pulmonate gastropod mollusks.... , Sphaeriidae Sphaeriidae The Sphaeriidae are a family of small to minute freshwater bivalve molluscs, in the order Veneroida. In the USA they are commonly known as the pea clams and the fingernail clams.-Genera:Genera in the family Sphaeriidae include:* Musculium... , Glossiphoniidae Glossiphoniidae Glossiphoniidae are the family called freshwater jawless leeches or glossiphoniids. They are one of the main groups of Rhynchobdellida, true leeches with a proboscis. These leeches are generally flattened, and have a poorly defined anterior sucker... , Hirudidae, Erpobdellidae Erpobdellidae Erpobdellidae is a family of leeches. They have three or four pairs of eyes, but never have true jaws, and are typically long. Most are scavengers on small invertebrates, which they often swallow whole.... , Asellidae Asellidae Asellidae is a family of isopod crustaceans. It is one of the largest families of freshwater isopods, living in both epigean and hypogean habitats in North America and Europe...	3
Midge Midge A midge is a very small, two-winged flying insect. "Midge" may also refer to:-Real:* Midge Costanza , American politician* Mildred Gillars , aka "Midge", American broadcaster of Nazi propaganda during World War II... s	Chironomidae Chironomidae Chironomidae are a family of nematoceran flies with a global distribution. They are closely related to the Ceratopogonidae, Simuliidae, and Thaumaleidae...	2
Worm Worm The term worm refers to an obsolete taxon used by Carolus Linnaeus and Jean-Baptiste Lamarck for all non-arthropod invertebrate animals, and stems from the Old English word wyrm. Currently it is used to describe many different distantly-related animals that typically have a long cylindrical... s	Oligochaeta Oligochaeta Oligochaeta is a subclass of animals in the biological phylum Annelida, which is made up of many types of aquatic and terrestrial worms, and this includes all of the various earthworms... (whole class)	1