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This sample was taken a short distance downstream from where we perform chemical tests each month on the quality of the water. We intend to carry out biological tests at this site on a regular basis to monitor the long term effects that water quality has on invertebrate life in the stream.
See the latest water quality test results for this location...
August 2008
A similar result to that of April 2007 but with a reduced ASPT. This stream suffers from low flows and high ammonia content every summer. The situation is unsatisfactory, but unlikely to improve.
| Location |
Bevern Stream tributary –Swansyard farm, nr Ditchling. |
| Date |
5th August 2008 |
| Grid Reference |
TQ340168 |
| Notes |
Pool approx. 5m diameter. 80 cm depth in centre, virtually stagnant. Exit riffle very shallow with minimal flow not recordable. Substrate clay/silt with scattered large stones and bricks. Heavily shaded.
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| Also netted in this sample. |
5 minnows, several empty caddis cases,? Oodontoceridae, 1 empty Sphaerium shell. |
| Biological quality rating |
C. Fair biological quality |
| Water quality rating |
Poor |
| Species |
Group |
BMWP Score |
| Calopterygidae |
Damsel nymph |
8 |
| Gammaridae |
Shrimp |
6 |
| Simuliidae |
Blackfly larvae |
5 |
| Tipulidae |
Cranefly larvae |
5 |
| Elminthidae |
Water beetle |
5 |
| Dytiscidae |
Water beetle |
5 |
| Baetidae |
Mayfly nymph |
4 |
| Asellus |
Hoglouse |
3 |
| Glossiphoniidae |
Leeches |
3 |
| Planorbiidae |
Ramshorn snail |
3 |
| Hydrobiidae |
Snail |
3 |
| Chironomidae |
Midge larvae |
2 |
| Oligochaetae |
Worms - Tubifex |
1 |
| Total Score |
53 |
| ASPT (Average Score Per Taxon) |
4.08 |
April 2007
This is a much improved score c.f. our last sampling (10.07.06). This is reflected by the improved water quality over the last few months. However, there is still a lack of biodiversity as indicated by the low BMWP score.
| Location |
Bevern Stream tributary –Swansyard farm, nr Ditchling. |
| Date |
19th April 2007 |
| Grid Reference |
TQ340168 |
| Notes |
Three minute kick sample from riffle and pool in shaded area with very low flow; substrate clay and fine gravel; no aquatic vegetation. |
| Also netted in this sample. |
One water mite. |
| Biological quality rating |
D. Poor biological quality |
| Water quality rating |
Good |
| Species |
Group |
BMWP Score |
| Leptophlebiidae |
Mayfly nymphs |
10 |
| Leptoceridae |
Cased caddis |
10 |
| Baetidae |
Mayfly nymphs |
6 |
| Gammaridae |
Shrimp |
6 |
| Simuliidae |
Blackfly larva |
5 |
| Asellus |
Hoglouse |
3 |
| Glossiphoniidae |
Leeches |
3 |
| Planorbiidae |
Ramshorn snail |
3 |
| Chironomidae |
Midge larvae (mostly bloodworms) |
2 |
| Oligochaetae |
Worms - Tubifex and others |
1 |
| Total Score |
49 |
| ASPT (Average Score Per Taxon) |
4.9 |
July 2006
This very low score, including the ASPT, demonstrates the poor water quality at this site. The findings are unsurprising as our chemical testing on 2 nd July 2006 showed an ammonia level (as N) of 3.9 mg/litre. Only one or two of each species were netted in this sample.
| Location |
Bevern Stream tributary –Swansyard farm, nr Ditchling. |
| Date |
10th July
2006 |
| Grid Reference |
TQ340168 |
| Notes |
Three minute kick sample from riffle and pool in shaded area with very low flow; substrate clay and fine gravel; no aquatic vegetation. |
| Also netted in this sample. |
12 three spined sticklebacks. |
| Biological quality rating |
D. Poor biological quality |
| Water quality rating |
Poor |
| Species |
Group |
BMWP Score |
| Gammaridae |
Shrimp |
6 |
| Hydrophilidae |
Water beetle – Helophorus |
5 |
| Asellus |
Hoglouse |
3 |
| Chironomidae |
Midge larvae (mostly bloodworms) |
2 |
| Total Score |
16 |
| ASPT (Average Score Per Taxon) |
4.0 |
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