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Biological Monitoring Working Party
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| Introduction |
BMWP scores for the locations sampled by S.O.C.S. can be viewed below: |
| River Ouse |
| East Mascalls |
| Scaynes Hill - Main river |
| Scaynes Hill - Canal Cut |
| Sheffield Park |
| Barcombe Mills |
| River Uck |
| Hempstead Mill - Uckfield |
| Bevern Stream |
| Stoneywish Country Park |
| Spatham Lane |
| Streat Lane |
| Swansyard Farm |
| Holmans railway bridge |
| Clapper's Bridge |
| North End Stream |
| Cooksbridge |
| Hamsey Road |
| Plumpton Mill Stream |
| Plumpton Mill |
| Ferrings Bridge |
| Longford Stream |
| Cinder Hill, Chailey |
| Ridgelands Lane - Newick |
| Longford Bridge |
| Pellingford Brook |
| Near Scaynes Hill |
| Scrase Stream |
| Lindfield |
| Great Bentley Stream |
| Brook Street, Cuckfield |
| Shortbridge Stream |
| Maresfield, Underhill |
| Shortbridge |
| Norlington Stream |
| Wellingham Lane |
| Lewes Winterbourne |
| Lewes Railwaylands |
| Bevern Stream at Spatham Lane, Nr Ditchling | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| 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... June 2010This result was no better than expected given the proximity to the STW and the low flow. As with the Northend Stream last week the score was made to look better by a single small caddis fly larva.
This sample was taken sooner than planned, as chemical water testing carried out on 4.6.10 showed an ammonia content of 6.54 mg/litre (as N) at this site. A test taken today showed a drop to 0.68 mg/litre. The BMWP score is slightly higher than in March 2010 and the ASPT is the same. However, a significant number of apparently recently dead organisms were netted including 3 bullheads, 20 shrimp, 2 baetis larvae, 30+ hydropsychid larvae and several simuliidae. This suggests that the transient high ammonia content caused widespread mortality. The stream has partially recovered, but is consistently underperforming in terms of biodiversity compared with expected values for a small chalk stream. |
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| Location | Bevern Stream –Spatham Lane, nr Ditchling. | |
| Date | 9th June 2010 | |
| Grid Reference | TQ336158 | |
| Notes | Low flow over gravel/silt substrate – part shaded. |
|
| Also netted in this sample. | 1 juvenile bullhead ( Cottus gobio) and a number of dead fish and other organisms (see below) | |
| Biological quality rating | C. Fair biological quality | |
| Water quality rating | Fair | |
| Species | Group | BMWP Score |
| Sericostomatidae | Cased caddis | 10 |
| Calopterygidae | Damsel nymph | 8 |
| Gammaridae | Shrimp | 6 |
| Elminthidae | Riffle beetle | 5 |
| Hydropsychidae | Caseless caddis | 5 |
| Simuliidae | Blackfly | 5 |
| Hydrophilidae | Water beetles | 5 |
| Baetidae | Mayfly nymph | 4 |
| Piscicolidae | Leech | 4 |
| Glossiphoniidae | Leech | 3 |
| Hydrobiidae | Snail | 3 |
| Asellidae | Hogloude | 3 |
| Chironomidae | Midge larvae | 2 |
| Oligochaeta | Worms (Tubificidae) | 1 |
| Total Score | 64 | |
| ASPT (Average Score Per Taxon) | 4.6 | |
March 2010
Results compatible with the proximity of the STW outfall.| Location | Bevern Stream –Spatham Lane, nr Ditchling. | |
| Date | 9th March 2010 | |
| Grid Reference | TQ336158 | |
| Notes | Moderate flow over stony riffle. Clear water. Partly shaded. |
|
| Also netted in this sample. | - | |
| Biological quality rating | C. Fair biological quality | |
| Water quality rating | Fair | |
| Species | Group | BMWP Score |
| Leptoceridae | Cased caddis | 10 |
| Limnephilidae | Cased caddis | 7 |
| Gammaridae | Shrimp | 6 |
| Elmidae | Riffle beetle | 5 |
| Hydropsychidae | Caseless caddis | 5 |
| Simuliidae | Blackfly | 5 |
| Baetidae | Mayfly nymph | 4 |
| Piscicolidae | Leech | 4 |
| Glossiphoniidae | Leech | 3 |
| Hydrobiidae | Snail | 3 |
| Chironomidae | Midge larvae | 2 |
| Oligochaeta | Round worm | 1 |
| Total Score | 55 | |
| ASPT (Average Score Per Taxon) | 4.6 | |
October 2009
A reasonable result considering that the water is almost entirely treated sewage effluent producing black and fairly evil smelling silt. | Location | Bevern Stream –Spatham Lane, nr Ditchling. | |
| Date | 14th October 2009 | |
| Grid Reference | TQ336158 | |
| Notes | Very low flow. Shaded, silted stream bed and a short riffle. |
|
| Also netted in this sample. | 2 Bullheads Cottus gobio, about 20 empty Spire-shell Potamopyrgus jenkinsi and 1 empty Wandering Pond Snail shell Lymnaea peregra. | |
| Biological quality rating | C. Fair biological quality | |
| Water quality rating | Fair | |
| Species | Group | BMWP Score |
| Leptoceridae | Cased caddis | 10 |
| Calopterygidae | Demoiselle | 8 |
| Gammaridae | Shrimp | 6 |
| Elmidae | Riffle beetle | 5 |
| Hydropsychidae | Caseless caddis | 5 |
| Baetidae | Mayfly nymph | 4 |
| Piscicolidae | Leech | 4 |
| Glossiphoniidae | Leech | 3 |
| Lymnaeidae | Snail | 3 |
| Asellus | Hoglouse | 3 |
| Chironomidae | Midge larvae | 2 |
| Tubificidae | Round worm | 1 |
| Total Score | 54 | |
| ASPT (Average Score Per Taxon) | 4.5 | |
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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