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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...
May 2008
The discharge volume from the sewage treatment works is now very low. There is evidence of marked silt deposition in the pool areas and a growth of filamentous algae. This result is even worse than the poor ones recently obtained further upstream and is indicative of more than one sources of pollution.
| Location |
Bevern Stream –Spatham Lane, nr Ditchling. |
| Date |
12th May 2008 |
| Grid Reference |
TQ336158 |
| Notes |
Three minute kick sample in
clear water over stony riffle but with a covering of silt
|
| Also netted in this sample. |
One Bullhead ( Cottus gobio). Gammarus infected with Echinorrhyncus sp Spiny-headed worm. |
| Biological quality rating |
D. Poor biological quality |
| Water quality rating |
Poor |
| Species |
Group |
BMWP Score |
| Gammaridae |
Shrimp |
6 |
| Elminthidae |
Water beetle |
5 |
| Simuliidae |
Blackfly larvae |
5 |
| Hydropsychidae |
Caseless caddis
larvae |
5 |
| Baetidae |
Mayfly nymph (in profusion) |
4 |
| Glossiphoniidae |
Leech |
3 |
| Lymnaeidae |
Snail |
3 |
| Asellidae |
Hog louse |
3 |
| Chironomidae |
Midge larvae |
2 |
| Total Score |
36 |
| ASPT (Average Score Per Taxon) |
4 |
March 2007
This is a similar result to the upstream sites, with low biodiversity. At this time of the year, the discharge from Ditchling STW does not appear to be having any significant impact.
| Location |
Bevern Stream –Spatham Lane, nr Ditchling. |
| Date |
23rd March 2007 |
| Grid Reference |
TQ336158 |
| Notes |
Three minute kick sample in stony riffle. Moderate flow for this site. |
| Also netted in this sample. |
3 Bullheads |
| Biological quality rating |
C. Fair biological quality |
| Water quality rating |
Fair |
| Species |
Group |
BMWP Score |
| Sericostomatidae |
Cased caddis |
10 |
| Gammaridae |
Shrimp |
6 |
| Elminthidae |
Water beetle |
5 |
| Simuliidae |
Blackfly larvae |
5 |
| Hydropsychidae |
Caseless caddis |
5 |
| Baetidae |
Mayfly nymph (in profusion) |
4 |
| Glossiphoniidae |
Leech |
3 |
| Erpobdellidae |
Leech |
3 |
| Hydrobiidae |
Snails (in profusion) |
3 |
| Chironomidae |
Midge larvae |
2 |
| Oligochaeta |
Worms ( mainly Tubifex ) |
1 |
| Total Score |
47 |
| ASPT (Average Score Per Taxon) |
4.3 |
July 2006
Although low, this score is surprisingly good considering the very poor water quality measured at this location in July. Both the BMWP score and ASPT are however lower than those of July 2005.
| Location |
Bevern Stream –Spatham Lane, nr Ditchling. |
| Date |
4th July 2006 |
| Grid Reference |
TQ336158 |
| Notes |
Three minute kick sample in silt
substrate
with very low flow and
extremely shallow, coloured water. |
| Also netted in this sample. |
1 Bullheads
1 Pond Skater |
| Biological quality rating |
D. Poor biological quality |
| Water quality rating |
Very poor |
| Species |
Group |
BMWP Score |
| Gammaridae |
Shrimp |
6 |
| Elminthidae |
Water beetle |
5 |
| Piscicola geometra |
Fish leech |
4 |
| Chironomidae |
Midge larvae |
2 |
| Oligochaeta |
Worms (Tubifex and Lumbriculus) |
1 |
| Total Score |
18 |
| ASPT (Average Score Per Taxon) |
3.6 |
November 2005
This is a marked improvement on the September 2005 index. However, both the BMWP and ASPT scores are relatively low, with a noticeable lack of pollution sensitive species.
| Location |
Bevern Stream –Spatham Lane, nr Ditchling. |
| Date |
22nd November
2005 |
| Grid Reference |
TQ336158 |
| Notes |
This stream now has a reasonable flow, but not as much as should be expected at this time of the year. 3 minute kick sample taken in gravel riffle area downstream from road bridge. |
| Also netted in this sample. |
3 Bullheads |
| Biological quality rating |
D. Poor biological quality |
| Water quality rating |
Poor |
| Species |
Group |
BMWP Score |
| Gammaridae |
Shrimp |
6 |
| Elminthidae |
Water beetle |
5 |
| Helodidae |
Water beetle |
5 |
| Simuliidae |
Blackfly larvae |
5 |
| Hydropsychidae |
Caddis fly larvae |
5 |
| Baetidae |
Mayfly nymph (in profusion) |
4 |
| Piscicolidae |
Leech |
4 |
| Glossiphoniidae |
Leech |
3 |
| Lymnaeidae |
Snail |
3 |
| Hydrobiidae |
Snails
(in profusion) |
3 |
| Chironomidae |
Midge larvae (mostly bloodworms) |
2 |
| Oligochaeta |
Worms (
Tubifex, in profusion and 2 Gordian worms
) |
1 |
| Total Score |
46 |
| ASPT (Average Score Per Taxon) |
3.8 |
September 2005
This is a seriously low score for what should be a chalk stream habitat. Only one Gammarus was found in the sample and the few Chironomus were all of the red bloodworm variety, which are tolerant to low dissolved oxygen levels as they contain a haemoglobin like pigment to aid respiration.
| Location |
Bevern Stream –Spatham Lane, nr Ditchling. |
| Date |
1st September 2005 |
| Grid Reference |
TQ336158 |
| Notes |
Due to the extremely low flow, it was impossible to take a kick sample from the riffle areas of this stream. The sample was therefore taken from the pool immediately downstream from the Spatham Lane culvert. Substrate - fine woody debris on clay. Depth average 0.6 metres. |
| Also netted in this sample. |
2 Bullheads |
| Biological quality rating |
E. Very poor biological quality |
| Water quality rating |
Poor |
| Species |
Group |
BMWP Score |
| Gammaridae |
Shrimp |
6 |
| Chironomidae |
Bloodworm |
2 |
| Total Score |
8 |
| ASPT (Average Score Per Taxon) |
4 |
July 2005
This very low score including the
ASPT score is disappointing for a chalk stream. This is probably
due to the scant flow, most of which comprises effluent from Ditchling
STW. Gammaridae and Elminthidae were present in profusion, but only
one stonefly nymph was found. An empty mussel shell (probably sphaerium)
was found, but no live specimens.
| Location |
Bevern Stream –Spatham
Lane, nr Ditchling. |
| Date |
5th July 2005 |
| Grid Reference |
TQ336158 |
| Notes |
Three minute kick sample
in stony riffle with very low flow;
extremely shallow water. |
| Also netted in this sample. |
2 Bullheads |
| Biological quality rating |
D. Poor biological quality |
| Water quality rating |
Fair |
| Species |
Group |
BMWP Score |
| Nemouridae |
Stonefly (Leuctrid) |
10 |
| Gammaridae |
Shrimp |
6 |
| Elminthidae |
Water beetle |
5 |
| Glossiphoniidae |
Leech |
3 |
| Planorbidae |
Ramshorn Snail |
3 |
| Hydrobiidae |
Snails |
3 |
| Oligochaeta |
Worms (Tubifex and Lumbriculus) |
1 |
| Total Score |
31 |
| ASPT (Average Score
Per Taxon) |
4.4 |
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