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NRA
National Rivers Authority Anglian Region NATIONAL RIVERS AUTHORITY ANGLIAN REGION IPSWICH
A REVIEW OF THE QUALITY AND STATUS OF THE SUFFOLK AND ESSEX ESTUARIES AND COASTAL WATERS
MAY 1993
AUTHOR — G R Xi BURRELL BSc.HONS MARINE TECHNICIAN
C I M°ARTHUR BA HONS,DipIWEM MARINE SCIENTIST
FINAL DRAFT M W JOHNSON MSc VOLUME 1 MARINE BIOLOGIST
ENVIRONMENT AGENCY
124364 SUMMARY
The objective of this report was to bring together all the pertinent details with respect to matters influencing estuarine and coastal water quality. This data gained was then used in assessing the quality status of each estuary, utilising chemical and biological data.
Historical data has also been brought together in one document for the first time, to give a perspective of changes that have occurred over several decades.
Taking into account all relevant factors influencing water quality the following grades for the estuaries were derived: (For full table of results see Table 1.)
Excellent - Ore/Aide Good - Stour, Walton Backwaters, Blyth and Blackwater Fair - Deben, Crouch and Roach Poor - Orwell and Colne
Unexpected results were attained from the Blackwater, where, considering the high proportion of effluent in its upper reaches we anticipated poor quality, and the Colne, which is far worse than previously supposed, mainly due to the input from Colchester STW.
Coastal waters have limited chemical and biological data but enough to surmise that water quality is excellent. However, levels of some heavy metals are cause for concern and increased monitoring is required. SABLE 1
SUFFOLK AND ESSEX ESTUARINE SCORING SYSTEM.
r* ESTUARY CHEMICAL BENTHIC SHELLFISH NUTRIENTS/ AESTHETIC CONSERVATION SCORE OVERALL QUALITY QUALITY QUALITY ALGAL PROD. QUALITY STATUS QUALITY
ORE/ALDB 5 4 5 3 5 A 27A EXCELLENT
STOUR 4 5 5 4 3 A 26A GOOD WALTON BACKWATERS 4 4 4 4 4 A 25A GOOD
BLYTH 5 4 4 3 4 A 25A GOOD
BLACKWATER 4 5 4 4 4 B 25B GOOD
DEBEN 4 4 3 1 3 B 19B FAIR
CROUCH 4 3 3 3 3 C 19C FAIR
ROACH 3 3 3 3 3 C 18C FAIR
ORWELL 2 2 2 4 1 B 15B POOR
COLNE 2 1 4 2 2 C 14C POOR
1-2-3-4-5 A-B-C-D-E POOR GOOD HIGH CONS. LON CONS. QUALITY QUALITY STATUS STATUS MAP 1 I HE ESSEX AND SUFFOLK ESTUARIES
b l y t h
ORE/ALDE
ORWELL
STOUR
WALTON BACKWATERS
CROUCH
ROACH PLATE 1
River Orwell at low water looking under the Orwell Bridge into Ipswich Commercial Docks. Also used for dinghy sailing. CONTENTS
Volume__ 1
SUMMARY, TABLE 1, MAP 1 AND PLATE 1
CONTENTS
SECTION A INTRODUCTION
1 BLYTH PAGE 1 -■ 6 2 ORE/ALDE PAGE 7 -■ 13 3 DEBEN PAGE 14 - 19 4 ORWELL PAGE 20 - 28 5 STOUR PAGE 29 - 34 6 WALTON BACKWATERS PAGE 35 - 40 7 COLNE PAGE 41 - 47 8BLACKWATER PAGE48- 54 9 CROUCH PAGE 55 - 60 10 ROACH PAGE 61 - 64
SECTION B CHEMICAL WATER QUALITY TRENDS
1 BLYTH PAGE 65 - 72 2 ORE/ALDE PAGE 73 - 81 3 DEBEN PAGE 82 - 91 4 ORWELL PAGE 92 - 100 5 STOUR PAGE 101 - 115 6 WALTON BACKWATERS PAGE 116 - 126 7 COLNE PAGE 127 - 148 8BLACKWATER PAGE149 - 169 9CROUCH PAGE170 - 187 10 ROACH PAGE 188 - 200 CONTENTS (Continued) Volume 2
SECTION C ESTUARINE BENTHIC STATUS PAGE 201 217
SECTION D NUTRIENT AND CHLOROPHYLL STATUS PAGE 218 226
SECTION E HEAVY METAL STATUS PAGE 227 230
SECTION F OFF SHORE FISHERY STATUS PAGE 231 232
SECTION G BATHING WATER QUALITY PAGE 233 238
SECTION H WATER QUALITY MODELS PAGE 239
SECTION I CONCLUSIONS AND RECOMMENDATIONS PAGE 240 245
APPENDICES 1 - 1 5
BIBLIOGRAPHY 1 - 3 SECTION A]
INTRODUCTION A] INTRODUCTION
1 BLYTH ESTUARY
The Blyth estuary is a bar built estuary with an area of 311 ha. The upper estuary has a narrow channel that opens out into a wide, sheltered intertidal flat downstream of Blythburgh. Since the mid 19th century this area has been allowed to return to its natural state after being reclaimed as grazing marsh. The lower estuary is a narrow channel entering the sea at Southwold, the channel is surrounded on either side by grazing marshes which support a diverse population of invertebrate fauna.
The Blyth estuary tidal catchment has a population of less than 1.000 with two main treated sewage inputs at Wangford and Southwold. The water quality of the Blyth estuary has been classed by NRA as grade A. However, the River Wang, a tributary of the Blyth has been classed as grade 4 due to the quality of treated effluent being discharged from Bernard Matthews factory.
1.1 DESIGNATIONS (Map 2)
The SSSI of Minsmere and Walberswick heath and marshes, adjacent to the Blyth estuary covering an area of over 2003 ha, includes most of the intertidal mudflats of the Blyth estuary. This area is also a National Nature Reserve. The area of Minsmere and Walberswick was designated a RAMSAR site in 1976 and has recently been proposed as an SPA site. The estuary is also part of the Suffolk Coast and Heaths AONB.
The Suffolk Wildlife Trust and the RSPB consider areas of the estuary to be very important for wildlife and birds, particularly the adjoining site at Minsmere.
The reasons for these notifications are many, the tidal mudflats form sheltered feeding grounds for wild fowl and shore birds.
1 The shingle beach, although being eroded, supports a variety of scarce shingle plants and the reed beds provide a habitat for various birds and insects. The shallow lagoons at Minsmere are very important for a colony of Avocets and the large area of heathland provides a valuable habitat for the Nightjar and the Woodlark, two nationally declining birds.
1.2 USES (Map 3)
1.2.1 RECREATION: Where the Blyth estuary widens numerous recreational activities occur, although the majority of the estuary is not accessible and therefore undisturbed. There are numerous harbour moorings along the channel for commercial and pleasure craft and a boat park at Southwold. Some dingy sailing occurs on the estuary, but most is out at sea. Power boating, windsurfing, water skiing and canoeing activities are practiced on the estuary from Blythburgh seaward. The Blyth estuary has a particularly difficult harbour entrance to navigate.
1.2.2 SHELLFISHERIES: Blythburgh Creek has a very small oyster and mussel shellfishery. Wolsey Creek contains an oyster shellfishery from which the oysters are uv treated. The oysters from both Blythburgh Creek and Wolsey Creek are EC class B. Both creeks come under the EC Shellfish Hygiene Regulation Directive 1993 but were not designated under the 1979 Shellfish Directive.
1.2.3 FISHERIES: Fyke netting for eels and bait digging for Arenicola marina (lugworm) and Nereis diversicolor (ragworm) occurs over some of the intertidal area in the lower estuary.
1.2.4 SEDIMENT EXTRACTION/DREDGING: Only maintenance dredging takes place along the Blyth estuary within the harbour confines.
2 1.3 INPUTS
1.3.1 EFFLUENTS: Southwold STW final effluent has a current consent of 120SS/1SOBOD and discharges into the harbour at Bailey Bridge. This STW also has a storm tank discharge which outfalls at the same site. Wangford STW final effluent has a present consent of 3OSS/2 OBOD and discharges into the freshwater river some 2 miles above the tidal sluice. Both Southwold and Wangford STW have full treatment and their existing quality is satisfactory with respect to NRA discharge consent conditions.
The Bernard Matthews factory causes a significant water quality deterioration in the upper reaches of the River Wang, its affects are discernable in the estuary where the Wang joins the main channel.
1.3.2 RIVERS: The Blyth has a very rural catchment containing only one small town, Halesworth. There are no industrial inputs into the river and the main land use around the estuary is agricultural, being cereal and pig farms. The tidal constraint is at Blyford Bridge but on occassion the flood gate is left down in winter and the estuary becomes saline above Blyford Bridge. The Blyth estuary does not possess a saline wedge.
3 1.4 SUMMARY
BLYTH ESTUARY
N6R TM4776 GEOMORPHIC TYPE BAR BUILT ESTUARY TIDAL TYPE MESOTIDAL TOTAL AREA ha 311 INTERTIDAL AREA ha 235 SHORELINE km 25.4 TIDAL CHANNEL km 10.8 AREA OF MUDFLATS ha 276 AREA OF SALTMARSH ha 55 TIDAL LIMIT BLYFORD BRIDGE POPULATION <1000 NRA SURVEY CLASS A SEWAGE INPUTS SOUTHWOLD WANGFORD DESIGNATIONS SSSI, NNR, RAMSAR, AONB, SPA. RECREATION USES CANOEING, SAILING, WINDSURFING, POWER BOATING, WATER SKIING. SHELLFISHERIES WOLSEY CREEK BLYTHBURGH CREEK° FISHERIES FYKE NETTING AND BAIT DIGGING IMPORTANT BIRD SPECIES AVOCET AND SPOTTED REDSHANK
4 A 2 MAP BLYTH ESTUARY DESIGNATIONS
NATIONAL NATURE RESERVE A 3 MAP BLYTH ESTUARY Wangford STW USES AND INPUTS
WENHASTON
SHELLFISHERIES
RECREATION V Z l
SEWAGE TREATMENT WORKS 2 ORE/ALOE ESTUARY
The Ore/Alde estuary is a bar built estuary with a total area of over 1820 ha. The estuary is dominated by the Orfordness shingle spit, known as Orford Beach. This spit is one of three major shingle landforms in the British Isles and the only one to combine a shingle spit with a cuspate foreland. Ord Beach possesses highly specialised shingle vegetation, and a diverse population of lichens and bryophytes. The lagoons to the west of the estuary mouth have a specialist invertebrate fauna and are very important in terms of botanical and ornithological value.
v The River Aide flows into the River Ore at Or ford, the Ore thein continues to the estuary mouth. The Ore is deeper and more narrow than the Aide with less mudflat area. Along the fringes of both rivers saltmarsh is dominant, however, the saltmarsh on the Ore shows signs of erosion.
The Ore/Alde tidal catchment has a population of less than 1000 and has only one treated sewage input at Orf ord. The water quality haB been classed by NRA as grade A.
The shellfishery at Butley Creek is a very important historical oysterage, it was designated under the original EC Shellfish Directive 1979 and is classified as a class A fishery under the Shellfish Hygiene Directive 1993.
2.1 DESIGNATIONS (Map 4) The whole of the Ore/Alde estuary is an SSSI, from Bawdsey to Aldeburgh, for biological and geomorphilogical reasons, the area that the SSSI covers is also covered by the designation of AONB. The SSSI includes the Orfordness-Havergate NNR. It is considered to be an Environmentally Sensitive Area (ESA) and is partly designated as an SPA. At present the Ore/Alde estuary is a proposed RAMSAR site. The Suffolk Wildlife Trust have a reserve at Snapes Saltings and the RSPB have one at Havergate Island. Orfordness was purchased by the National Trust in April 1993 and will be managed as a Nature Reserve.
The reasons for notification are mainly due to the variety of habitats present at this site. In places the intertidal mudflats support the rare intertidal flowering plant, Zostera angustifolia (Eel grass). The saltmarsh areas support a wide variety of species including the rare Tasselpondweeds Ruppia spirilis and R . maritima. Sea Pea and Sea Kale can be found on the exposed and shifting shingle.
The site is of national importance for its birdlife. Havergate Island holds the largest breeding colony of Avocets in Britain. Another nationally important species, the Wigeon, is also present during migration.
The lagoons west of the estuary mouth are notable for a number of rare brackish water invertebrate species including the anthozoan Nematostella vectensis.
2.2 USES (Map 5) 2.2.1 RECREATION: Sailing occurs throughout most of the estuary and there are moorings with associated dingy parks at Aldeburgh and Orford. Windsurfing and canoeing are permitted as is power boating, but speed is limited. Bathing occurs at the estuary mouth, Orford and Iken Beach.
2.2.2 SHELLFISHERIES: There are two shellfisheries on the estuary, at But ley Creek and Stoneyditch. Butley Creek has been designated under the EC Shellfish Hygiene Directive 1993 and is at present of class A standard. The oysters collected from this creek undergo a two- phase treatment system, they are layed in the creek and then transferred to a holding tank. The creek is clean, but occasional contamination by seabirds and boats causes uncontrollable contamination peaks. Stoneyditch contains a
8 mussel shellf ishery, at present it is also class A. It is a very clean creek and is not affected by the adjacent STW at Orford, since it is situated within the Orfordness complex.
2.2.3 FISHERIES: Fyke netting for Eels and fish trawling for Plaice, Dab and Cod is practiced on the estuary. Some bait digging occurs for Lugworm and Ragworm around Aldeburgh.
2.3 INPUTS
2.3.1 EFFLUENTS: Orf ord STW has a present consent of 3 OSS/15BOD/10 AMMONIA and discharges some 1/2 km downstream of the village. It undergoes full treatment and is, at present, satisfactory with respect to NRA discharge conditions. Aldeburgh STW discharges into the North Sea after maceration and has a descriptive consent standard. It currently meets its discharge consent conditions.
2.3.2 RIVERS: The Ore/Alde estuary has a very rural catchment similar to the Blyth estuary. Within the catchment area the land use is mainly cereal agriculture and forestry. The tidal constraint on the Aide is at Snapes sluice and on Butley River it is at But ley Mill. The Ore/Alde estuary does not possess a saline wedge. PLATE 2
ORFORDNESS - The unique shingle spit is in the foreground and supports many rare plants and birds. Stoneyditch is the mussel fishery in the centre of the picture, the tidal River Ore/Alde is infront of Orford village and castle.
10 2.4 SUMMARY
ORE/ALDE ESTUARY
NGR TM4357 GEOMORPHIC TYPE BAR BUILT ESTUARY TIDAL TYPE MESOTIDAL TOTAL AREA ha 1821 INTERTIDAL AREA ha 1331.9 SHORELINE km 73.2 TIDAL CHANNEL km 28 AREA OF MUDFLATS ha 536 AREA OF SALTMARSH ha 341 TIDAL LIMIT SNAPES SLUICE & BUTLEY MILLS POPULATION <1000 NRA SURVEY CLASS A SEWAGE INPUTS ORFORD DESIGNATIONS SSSI, NNR, AONB, ESA, SPA. RECREATION USES SAILING, CANOEING, WINDSURFING, BATHING. SHELLFISHERIES BUTLEY CREEK STONEYDITCH FISHERIES FYKE NETTING & TRAWLING. IMPORTANT BIRD SPECIES AVOCET & WIDGEON
MAP 5 Snape Sluice
SHELLFISHERIES
RECREATION Y Z2
ORFOND NL: SS
HOLLESLEV BAY
13 3 DEBEN ESTUARY
The Deben estuary is a an example of a coastal plain estuary with a total area of 1007 ha. It is an estuary that is over 12km long with 251ha of saltmarsh. It supports 40% of Suffolks area of saltmarsh, from Melton to Bawdsey. The Deben estuary is narrow and relatively sheltered with extensive mudflats on its inner reaches with more sandy deposits occurring where exposed Red Crag erodes from the cliffs. Historically the saltmarsh and mudflats have been lost to agriculture as reclaimed land.
The estuary supports a diverse saltmarsh community including some uncommon species of invertebrate fauna. The estuary is also very important for over-wintering waders and wildfowl.
The Deben tidal catchment has population of over 10 000 mainly from the towns of Woodbridge, Wikcham Market and Debenham. It has two main treated sewage inputs at Melton and Woodbridge. The water quality has been classified by NRA as grade B for a small section in the upper reaches and grade A further downstream. The tidal limit of the estuary is at Ufford Mill.
The estuary supports three small shellfisheries at Methersgate quay, Waldringfield and Shottisham Creek. Shottisham Creek is a small oysterage, whereas the other two are mussel shellfisheries.
3.1 DESIGNATIONS (Map 6)
The estuary lies within the Suffolk Coast and Heaths AONB and the Suffolk Heritage Coast. It is also part of the Suffolk River Valleys ESA, and has been proposed as a RAMSAR and SPA site. The designated SSSI area covers 976 ha which is most of the estuary. The reasons for notification include the estuaries importance with respect to the Redshank that overwinter on the estuary. The site is also important for the winter populations of Dark-bellied
14 Brent Goose, Shelduck and Black-tailed Godwit.
As mentioned before the estuary supports 40% of Suffolks area of saltmarsh which also displays the most complete range of the floral community types in the county. The estuary supports three nationally scarce plant species; Marsh Mallow, Shrubby seablite and Small cord grass. The nationally rare mollusc Vertigo auqusior and the nationally scarce V. pusilla have been recorded on the estuary.
3.2 USES (Map 7)
3.2.1 RECREATION: Water contact sports on the estuary are numerous. Sailing, windsurfing and canoeing take place over much of the estuary and water skiing is permitted in Falkenham Creek. There are large numbers of moorings at Woodbridge, Waldringfield and Felixstowe Ferry and a marina at Woodbridge.
3.2.2 SHELLFISHERIES: There are three shellfisheries on the Deben estuary. Shottisham Creek has an oysterage of class B, Methersgate Quay has a mussel shellfishery of class C and Waldringfield has a mussel shellf ishery of class B. None of the three sites are designated under the original EC Shellfish Directive 1979. The sites are not commercial and are owned by several people, the necessity of a depuration plant makes the sites commercially unviable.
3.2.3 FISHERIES: Trawling and seine-netting for fish occurs over a small area of the estuary.
3.2.4 INDUSTRY: The industrial activity on the estuary is small but includes a working tidal mill and several boat yards at Woodbridge, Waldringfield and Old Felixstowe. There is also a small extensively used public quay at Feixstowe Ferry.
15 3.3 INPUTS
3.3.1 EFFLUENTS: There are two main treated sewage inputs into the Deben, at Woodbridge and at Melton. Melton STW has a current consent of 6OSS/4OBOD, has full treatment, and the existing quality is satisfactory. Woodbridge STW has a current consent of 70SS/35BOD, it also undergoes full treatment and its quality is satisfactory with respect to its consent conditions.
3.3.2 RIVERS: The tidal limit of the Deben is at Ufford Mill and the estuary does not possess a saline wedge. The catchment is largely agricultural cereal farming, with some forestry. And large numbers of agricultural licensed abstractors along the freshwater river result in low residual flows entering the estuary.
16
i 3.4 SUMMARY
DEBEN ESTUARY
NGR TM2945 GEOMORPHIC TYPE COASTAL PLAIN TIDAL TYPE MESOTIDAL TOTAL AREA ha 1007 INTERTIDAL AREA ha 687.4 SHORELINE km 49.8 TIDAL CHANNEL km 19 .7 AREA OF MUDFLATS ha 447 AREA OF SALTMARSH ha 251 TIDAL LIMIT MELTON MILL POPULATION 10 000 NRA SURVEY CLASS A, UPPER REACHES B SEWAGE INPUTS WOODBRIDGE, MELTON DESIGNATIONS SSSI, AONB, ESA. RECREATION USES SAILING, CANOEING, WINDSURFING, WATER SKIING. SHELLFISHERIES SHOTTISHAM CREEK, WALDRINGFIELD, METHERSGATE QUAY FISHERIES TRAWLING & SEINE NETTING IMPORTANT BIRD SPECIES REDSHANK, DARK BELLIED BRENT GOOSE, SHELDUCK, BLACK-TAILED GODWIT
17 MAP 6 Melton Mill
DEBEN ESTUARY WOODBRIDGE f u ~ s / DESIGNATIONS s f *__
AREA OF OUTSTANDING NATURAL BEAUTY Whole area
SITE OF SPECIAL SCIENTIFIC INTEREST ^ ^
18
4 ORWELL ESTUARY
The Orwell estuary is a coastal plain estuary with an area of 1785 ha. The tidal channel of the Orwell estuary extends about 20 km from Constantine Weir in Ipswich to Feixstowe. The intertidal zone of the upper estuary has been extensively developed to create Ipswich dock. The intertidal flats consist of a wide diversity of substrates but are dominated by fine silt. It is a long, narrow and relatively sheltered estuary that is heavily influenced by the sea.
Saltmarshes have developed within the embayinente and although they are not large they support a diverse floral population. The most extensive areas are at Levington and Colton Creeks.
The Orwellb lower reaches are adjacent to the Stour estuary, at the mouth the estuary is dominated by the ports of Harwich and Felixstowe.
During the last century the Orwell estuary has come under increasing pressure from both industrial and recreational activities that substantially affect the water quality of the estuary.
With a tidal catchment population of 155,000 the Orwell has sewage treatment works at Cliff Quay, Levington, Shotley and Felixstowe South. The high numbers of discharge points have resulted in mixed water quality. It moves from a grade D in the fr upper reaches improving to grade A at the mouth. There are 9.5 km of grade A quality, 8 km of grade B, 2 km of grade C and 2 km of grade D.
Industrial effluent also enters from treatment works at British Sugar Corporation (Sproughton), Pauls Malt (Ipswich), Felixstowe Tankstore, Ancliffe and British Fermentation (Felixstowe). The mid estuary is flanked by farmland and wet meadows and much
20 of the industry around the estuary is agriculture related. The freshwater marshes near the estuary mouth provide a habitat for waterfowl, breeding waders and sea birds, some internationally and nationally important species roost here.
Occasional cockle and mussel collection takes place at Nacton shores but it is not extensive and is class C under the E . C. Shellfish Hygiene Directive 1993.
4.1 DESIGNATIONS (Map 8)
The Orwell estuary is part of the Suffolk Coast and Heaths Area of Outstanding Natural Beauty and part of the Stour-Orwell proposed SPA and RAMSAR site. 1229.4 ha of the Orwell estuary has been designated as an SSSI, it extends from the New Channel at Ipswich to Shotley Point at Harwich Harbour. The reasons for its notification are the large numbers of wading birds visiting the estuary in winter including the Redshank, Dunlin and Turnstone. Up to 18 species of wildfowl winter on the estuary such as Wigeon, Shelduck and the Dark bellied Brent Goose.
The extensive mudflats support large patches of Eel grass Zostera marina, and Dwarf Eel grass, 2. noltii. The nationally rare plant, the Stinking goosefoot, Chenopodium vulvuaria. can also be found on the eBtuary.
In addition to the designated areas there are Local Nature Reserves and Suffolk Wildlife Trust Reserves.
4.2 USES (Nap 9)
4.2.1 RECREATION: The Orwell estuary has a high amenity value. There are marinas at Wherstead, Shotley, Levington, Woolverstone and Ipswich with moorings at Pin Mill, Orwell and Freston.
21 Sailing, power boating, water skiing, canoeing and SCUBA diving all take place on the estuary. Canoeing tends to take place on the upper estuary, sailboarding from Ipswich to Levington and cruising from Ipswich to the estuary mouth.
4.2.2 SHELLFISHERIES: There is only a small, non commercial mussel and cockle shellfishery at Nacton shore, although potential exists in future in the lower reaches.
4.2.3 FISHERIES: Seine netting, tangle netting in the creeks, trawling and fyke netting for Eels occurs over most of the estuary. Bass is caught in limited numbers up to Pin Mill, Eels are prolific up to the freshwater limit, Grey mullet can be caught from the lock gates to Harwich and both Sole and Plaice can be found between Pin Mill and Felixstowe. Flounders, Skate and Dabs are found on the estuary but only in small numbers.
Bait digging occurs in 70% of the estuary margins and Lobster pots are used off Harwich and Felixstowe.
4.2.4 INDUSTRY: There are two large container ports at Ipswich and Felixstowe and two small boat building yards at Ipswich and one at Chelmondiston. Other associated industries in dock side areas include, malting, an oil depot and chemical storage.
4.2.5 SEDIMENT EXTRACTION AND DREDGING: Capital dredging has deepened the dock at Felixstowe and dredging maintains the shipping channels through the estuary at approximately 13 m. There are future plans to deepen the channel at Levington and Dovercourt.
22 4.3 INPUTS
4.3.1 EFFLUENTS: There are five main sewage outfalls affecting the tidal Orwell, Cliff Quay which has primary treatment and is considered to be of poor quality, Chantry and Levington, which both have full treatment and whose quality is compliant with respect to their NRA consents. Shotley STW only undergoes primary treatment and is considered to have marginal quality, Felixstowe South is macerated and only discharge on the ebb tide, with an effluent quality that is considered to be marginal. Both Shotley and Felixstowe South are scheduled to introduce secondary treatment under the UWWTD. Cliff Quay has a current consent of 300SS and is to have biological treatment by September 1995 to a 120mg/l BOD standard. Levington has a current consent of 60SS/ 40BOD, Shotley has a current consent of 200SS and Felixstowe South has an exemption order consent and discharges into the outer harbour.
The Orwell estuary has three trade wastes entering it from Burtons Confectionery Factory, which has recently closed down and Pauls Maltings both at Ipswich docks. The third being at British Sugar at Sproughton. Pauls and British Sugar are both balanced discharges, only discharging during specific tidal windows.
4.3.2 RIVERS: The tidal constraint on the Orwell estuary is at Horseshoe weir, Ipswich. There is no saline wedge present in the Orwell estuary for most of the time. The catchment land use of the Orwell is mainly agricultural, with cereal farming predominating. The small towns of Stowmarket and Needham Market do, however, have industry and associated trade discharges.
23 PLATE 3
River Orwell looking downstream towards Woolverstone — illustrating the use of the estuary for pleasure pursuits and wildfowl and waders.
24
PLATE 4
Foxes Marina, Wherstead. A typical East Coast estuaries marina that has an impact on the water quality of the estuary.
25
4.4 SUMMARY
ORWELL ESTUARY
NGR TM2338 GEOMORPHIC TYPE COASTAL PLAIN TIDAL TYPE MESOTIDAL TOTAL AREA ha 1786 INTERTIDAL AREA ha 577 SHORELINE km 51 TIDAL CHANNEL km 20 AREA OF MUDFLATS ha 713 AREA OF SALTMARSH ha 74 TIDAL LIMIT HORSESHOE WEIR POPULATION 155 000 NRA SURVEY CLASS UPPER REACHES D, LOWER REACHES A SEWAGE INPUTS CLIFF QUAY, CHANTRY LEVINGTON, SHOTLEY INDUSTRIAL INPUTS BURTONS, PAULS & BRITISH SUGAR DESIGNATIONS SSSI, AONB, ESA RECREATION USES SAILING, CANOEING, SCUBA DIVING, POWER BOATING, WATER SKIING. SHELLFISHERIES NACTON SHORES FISHERIES FYKE NETTING, TRAWLING, TANGLE NETTING, SEINE NETTING IMPORTANT BIRD SPECIES REDSHANK, SHELDUCK & DUNLIN
26
5 STOUR ESTUARY
The Stour estuary is a coastal plain estuary with a total area of 2531 ha. The Stour estuary runs almost due east west for 19 km between a tidal barrage upstream of Manningtree to Harwich. The banks are natural for most of its length and the width varies from 10 m to 2 km. A series of bays on both shores create an intertidal zone of up to 1.5 km in places leaving some 1600 ha of mud exposed at low water. Flourishing populations of Eel grass exist in the mid to lower reaches most notably in Holbrook Bay on the north shore and Copperas Bay on the south.
Much of the estuary is lined by sharply rising land or even boulder clay cliffs so there is little saltmarsh in this area, Erwarton Bay and Copperas Bay support the largest area of saltmarsh. Cattawade marshes at the top of the estuary is an area of grazing marsh with associated open water and fen, it is an important habitat for both flora and fauna. However erosion infront of the factories at Brantham has become a problem and is subject to an NRA investigation.
The tidal Stour catchment has a population of 17,000 and has three sewage outfalls into the estuary at Manningtree, Mistley and Holbrook. Harwich and Dovercourt sewage treatment works have outfalls into the North Sea. The water quality of the Stour estuary has been classe by NRA as grade A.
5.1 DESIGNATIONS (Map 8) The Stour estuary along with the Orwell estuary is a proposed SPA and RAMSAR site. It lies within the Suffolk River Valleys ESA and the Suffolk Coast and Heath AONB. 2150 ha of the estuary has been designated an SSSI for its biological and geological interest. The estuary also has an RSPB reserve at Copperas Bay and an Essex Wildlife Trust Reserve. Tourism is very important on the
29 estuary, it is 'Constable Country'and many people come here to paint and walk.
Notification reasons are due to the fact that the mud is extremely rich in invertebrates, also the estuary is relatively free from disturbance which enables the estuary to support internationally significant wildfowl and waders. The shoreline is one of the most natural in the region, often with low cliffs. The cliffs at Stutton and Wrabness contain nationally important geological exposures.
Nine species of wildfowl and wader occur in nationally important numbers including the Redshank, Grey Plover, Shelduck and Wigeon. The main concentration of birds is in Holbrook Bay,
The higher salt marsh is dominated by Saltmarsh grass, Puccinellia spp.. and Sea Purslane, Halimione portulacoides. The shoreline vegetation varies from oak dominated wooded cliffs, through scrub covered banks to coarse grasses over sea walls. The fauna found includes 43 notable species.
5.2 USES (Map 9)
5.2.1 RECREATION: The tidal Stour is used for boating activity in a traditional manner. The area hosts everything from commercial container ports and ferry terminals to local dinghy hards. There are at present only one marina that at Shotley, and moorings at Wrabness, Mistley and Holbrook. Water skiing is limited to a small section in the mid estuary, sailing occurs along the estuary but it is not intensive. Other water contact sports practised include Windsurfing and sailboarding.
5.2.2 FISHERIES: A variety of fish are netted up the estuary, they include Eels, Mullet, Bass and Herrings. Commercially the fish stocks within the estuaries are not viable for larger fisheries.
30 Bait digging for Lugworm and Ragworm also takes place over a small part of the estuary.
5.2.3 INDUSTRY: Industrial activity includes three ports at Mistley, Parkstone Quay and Harwich. There is a dock extension currently in construction at Bathside Bay. There are also two plastic film factories at Brantham but with only a small effluent discharge from each and limited estuarine impact. Two maltings exist at Mistley, discharging to the estuary via an AW pic sewer.
5.2.4 SEDIMENT EXTRACTION AND DREDGING: Capital dredging maintenance of the shipping channels occurs throughout the estuary, as well as some commercial estuarine aggregates extraction, which over the years has extensively damaged the bed channel.
5.3 INPUTS
5.3.1 EFFLUENTS: Manningtree STW undergoes full treatment with existing quality that is considered to be satisfactory. At present it has a consent of 75SS/ SOBOD/ 20AMMONIA. Mistley outfall has a consent of 50SS/50BOD and at present has no treatment, its existing quality is only marginal since it contains Maltings Steep Liquors. There are plans to treat the effluent for BOD reduction in 1994. Holbrook STW undergoes full treatment and is considered to be compliant with respect to its current consent of IOOSS/8OBOD. Both Harwich and Dovercourt effluent are untreated and their existing quality is consequently poor. There are plans to fully treat both effluents at a new site by 1999.
5.3.2 RIVERS: The tidal constraint on the Stour is at Cattawade sluice and Judas Gap. As with the Orwell the main catchment land use is agricultural and the area is of grade 2 and 3 under the MAFF classification scheme. It is mainly arable but there is
31 increasing reversion to grazing in the valleys. The industrial towns of Haverhill and Sudbury contribute significant volumes of treated trade and domestic effluent to the freshwater Stour. The flow in the River Stour is supplemented by water from the Ely- Ouse to Essex transfer scheme and the Stour Augmentation Groundwater Scheme.
There is no evidence of a saline wedge on the Stour estuary.
32 PLATE 5
Felixstowe Docks from the bathing beach at Harwich. Industrial discharges and dockside activities have an impact on water quality in the Stour/ Orwell area.
33
5.4 SUMMARY
STOUR ESTUARY
NGR TM1833 GEOMORPHIC TYPE COASTAL PLAIN TIDAL TYPE MESOTIDAL TOTAL AREA ha 2531 INTERTIDAL AREA ha 1637 SHORELINE km 48 TIDAL CHANNEL km 20 AREA OF MUDFLATS ha 1506 AREA OF SALTMARSH ha 95 TIDAL LIMIT CATTAWADE SLUICE POPULATION 17 000 NRA SURVEY CLASS A SEWAGE INPUTS MANNINGTREE, MISTLEY & HOLBROOK DESIGNATIONS SSSI, AONB, ESA RECREATION USES SAILING, WATER SKIING, WINDSURFING & SAILBOARDING FISHERIES FYKE NETTING, TRAWLING IMPORTANT BIRD SPECIES REDSHANK, GREY PLOVER, SHELDUCK, WIGEON
34 6 WALTON BACKWATERS
Walton Backwaters is a mesotidal embayment, it is not an estuary in the true sense. Walton Backwaters is a large, shallow estuarine basin whose mouth is about threee miles south of Harwich. It is flanked by two shingle spits, one from Dovercourt southwards and one from Naze northwards. The intertidal area is a mosaic of islands, tidal creeks, mudflats, sandflats and saltmarsh. Skippers Island was once formerly enclosed from the sea as grazing marsh, it has reverted to saltmarsh as a result of a breach in the seawall. The largest island Horsey Island is inhabited and farmed.
The mudflats are very rich in vegetation. There is a great diversity of waterfowl in winter, Wigeon often use the estuary as shelter during harsh winters. As with the Orwell the bird population is interchangable with the Stour.
Walton Backwaters tidal catchment has a population of less than 1,000 and has three main sewage effluents potentially affecting it; Walton, Dovercourt and Harwich. The EXCHEM factory on Bramble Island also discharges directly into the estuary of Bramble Creek. The water quality of Walton Backwaters has been classed as potentially grade A.'
The estuary supports two important commercial shellfisheries at The Twizzle and Kirby Creek both were designated under the EC Shellfish Directive 1979.
6.1 DESIGNATIONS (Map 10)
Walton Backwaters is a designated SSSI, the area notified covers an area of 2140 ha,' nearly the whole of the estuary. Most of this area is a National Nature Reserve and a Nature Conservation
35 Review Site. The Nature Reserve on Skippers Island is managed by the County Wildlife Trust. Walton Backwaters has been proposed as a SPA and RAMSAR site.
The reasons for notifications are due to its international importance for breeding Little Terns and overwintering Dark- bellied Brent Geese, wildfowl and waders. Walton Backwaters supports rare communities of of coastal plants, including Hog's Fennel Peucedanum officinale.
Extensive salt marsh covers one third of the area providing a habitat for flora such as Thrift, Rock Sea Lavender and Sea Aster. The uncommon Slender Hare's-ear is often found on the sea wall. The intertidal area supports an abundant invertebrate community comprising mainly of annelids and thin shelled molluscs. The mudflats support a number of local plants and area major feeding ground for approximatley 6,000 over wintering Brent Geese. Walton Backwaters is also home to the internationally important Shelduck, Teal, Grey Plover, Blacktailed Godwit and Sanderling.
6.2 USES (Map 11)
6.2.1 RECREATION: Aquatic sports take place all along the main Walton Channel and Hamford Water with the marina and moorings concentrated on Walton Channel and The Twizzle. Fishing, sailboarding, windsurfing, sailing and some water skiing occurs some areas of the estuary.
6.2.2 SHELLFISHERIES: Both The Twizzle and Kirby Creek are commercially important oyster shellfisheries and have been for the last 50 years. They are graded as class B under the Shellfish Hygiene Directive and are designated shellfisheries under the EC Shellfish Directive 1979.
36 6.2.3 FISHERIES: Fyke-netting for eels and trawling occurs over limited parts of the estuary, as does bait digging for Lugworm and Ragworm.
6.2.4 INDUSTRY: The EXCHEM explosives factory at Bramble Island discharges directly into the estuary at Bramble Creek. It is consented for a tidal discharge around high water only with limitation in respect of its chemical quality.
6.3 INPUTS
6.3.1 EFFLUENTS: The two main effluents potentially affecting Walton Backwaters are Walton, Dovercourt and Harwich. Walton undergoes full treatment and is at present meeting its consent of 100SS/95B()D. Harwich and Dovercourt have no treatment and enter the North Sea as crude sewage, they are both considered as having a poor quality.
6.3.2 RIVERS: There is no saline wedge in Walton Backwaters since it has no inputs.
No freshwater inputs of any significance enter the backwaters and the system is fully saline. Surrounding agricultural land is largely arable.
37 6.4 SUMMARY
WALTON BACKWATERS
NGR TM2325 GEOMORPHIC TYPE EMBAYMENT TIDAL TYPE MESOTIDAL TOTAL AREA ha 2377 INTERTIDAL AREA ha 1570 SHORELINE km 54 TIDAL CHANNEL km 8 AREA OF MUDFLATS ha 1400 AREA OF SALTMARSH ha 900 TIDAL LIMIT BEAUMONT QUAY POPULATION <1 000 NRA SURVEY CLASS A SEWAGE INPUTS WALTON (Seaward only) INDUSTRIAL INPUTS EXCHEM DESIGNATIONS NNR, SSSI RECREATION USES SAILING, WINSURFING, SAILBOARDING. FISHERIES FYKE NETTING & TRAWLING IMPORTANT BIRD SPECIES SHELDUCK, TEAL, GREY PLOVER, BLACK TAILED GODWIT & SANDERLING
38 A 10 MAP HAMFORD WATER DESIGNATIONS /' SITE OF SPECIAL SCIENTIFIC INTEREST < i // s - '
NATIONAL NATURE RESERVE /
Point
1 / THE NAZE
Thorpe le Soken
WALTON ON THE/NAZE MAP 11 7 COLNE ESTUARY
The Colne estuary is a coastal plain estuary with a total area of 2335 ha. The estuary is comparatively short and branching, with five tidal arms which flow into the main river channel, these tidal arms have extensive mudflats that are exposed at low tide. The intertidal flats become a mixture of mud and sand in the lower reaches of the estuary. The Colne has quite an extensive area of undisturbed saltmarsh of which the most notable areas are Fingringhoe and Geedons Creek, Colne Point on the eastern shore has saltmarsh that is showing signs of degradation.
At Colne Point two shingle spits exist which enclose a large area of saltings. Before the mid 19th century this area used to be extensive shingle ridges. The habitats that the Colne estuary provides are quite diverse, it supports a varied invertebrate fauna and supports a large number of wintering wildfowl.
The Colne estuary has a population of 107,000, the main centres of population being Colchester, Brightlingsea and Wivenhoe. The Colne has several sewage discharges that directly affect its quality; Jaywick, Brightlingsea, St. Oysth, Colchester and Fingrinhoe. The main body of water in the estuary has been classed as grade A, in terms of water quality, the upper reaches of the estuary have however been downgraded to grade B and C.
There are several important shellfisheries on the Colne estuary; Pyefleet Channel, Bench Head, Batchelor Spit, The Nothe and Buoy 13 at the harbour entrance, these have been in use since Roman Times but have been badly affected by TBT or Bonamia in recent times.
7.1 DESIGNATIONS (Map 12)
2,915 ha of the Colne estuary is covered by the designation of
41 SSSI. The SSSI includes a large area of National Nature Reserve and two Geological Conservation Review sites. Essex Wildlife Trust also manage reserves within the estuary at Abberton and Colne Point. The Colne estuary has been proposed as a SPA and RAMSAR site.
The reasons for SSSI notification are many, the variety of habitatB support outstanding assemblages of invertebrates and plants. The Colne estuary has a narrow intertidal zone predominantly composed of flats of fine silt with mudflat communities typical of south eastern estuaries where the fauna is dominated by Hydrobia ulvae. The nationally uncommon species, Golden Samphire, Inula crithmoides. and Shrubby Seablite, Suaeda vera, occur frequently in the upper marsh and at the foot of the sea walls. The transitional habitat that occurs from saltmarsh to sand dune is important for the rare Sea Heath, Frankenia laevis.
The saltmarsh and intertidal mud, with Mersea Flats provide an extensive feeding area of the internationally important Brent Geese. Redshank, Dunlin, Sanderling and Blacktailed Godwit are also present in nationally important numbers. The grazing marsh at East Mersea and the Geedon Saltings provide the main high tide roost for waders.
Much of the invertebrate interest is in the ungrazed marsh on Fingringhoe Ranges and it is believed to be the best Essex site for aquatic invertebrates outside the Thames estuary. Langenhoe is the only Essex site for the uncommon Hairy Dragonfly, Brachytron pratense.
7.2 USES (Map 13)
7.2.1 RECREATION: Water based sports are particularly dominant in the lower Colne estuary. Sailing and windsurfing occur over most of the estuary, but power boating and water skiing are restricted to
42 Brightlingsea Creek and East Mersea.
7.2.2 SHELLFISHERIES: There are important shellfisheries in the Colne estuary and around Mersea Island. The shellfisheries are all mussel shellfisheries with a grading of class B, apart from Bench Head, and Pyefleet Channel, which are oysterages of class A quality, Batchelor Spit and Buoy 13 are class B and The Nothe which is an oysterage of class C. Only Pyefleet Channel has been designated under the original E.C. Shellfish Directive 1979.
7.2.3 FISHERIES: Fish netting and trawling as well as fyke netting for eels occurs over much of the estuary.
7.2.4 INDUSTRY: There are small docks based at Brightlingsea, Wivenhoe, Rowhedge and Hythe. Brightlingsea also has a light engineering works and boat building yard. St. Osyth has a boat building yard and a gravel extraction area.
7.2.5 SEDIMENT EXTRACTION AND DREDGING: Capital dredging and maintenance dredging occurs along the entire estuary.
7.3 INPUTS 7.3.1 EFFLUENTS: There are several sewage effluents that potentially affect the Colne estuary; Jaywick outfall has no treatment and discharges into the North Sea, at present it has marginal quality but primary settlement is planned under the UWWWTD. Brightlingsea, St. Oysth, Colchester and Fingringhoe all have full treatment and are at present of variable quality in relation to their impact on the estuary. Colchester STW has a current consent of 60SS/25BOD, Fingringhoe has a consent of SOSS/25BOD, Brightlingsea has a consent of 8OSS/4OBOD, St. Oysth has a current consent of 60SS/5QBOD and Jaywick has an exemption order
43 consent.
7.3.2 RIVER: The tidal limit of the Colne estuary is at East Mills, Colchester. There is no apparent saline wedge on the Colne. The freshwater catchment is largely arable agricultural.
7.3.3 COLNE ESTUARY BARRAGE SCHEME: Currently in the course of construction is a barrier for flood defence purposes at Wivenhoe. It will remain open normally and be closed on 3 or 4 occasions a year with consequently little effect on water quality.
44 7.4 SUMMARY
COLNE ESTUARY
NGR TM0617 GEOMORPHIC TYPE COASTAL PLAIN TIDAL TYPE MACROTIDAL TOTAL AREA ha 2335 INTERTIDAL AREA ha 2002 SHORELINE km 90 TIDAL CHANNEL km 16 AREA OF MUDFLATS ha 700 AREA OF SALTMARSH ha 300 TIDAL LIMIT East Mills, Colchester POPULATION 107 000 NRA SURVEY CLASS A, UPPER REACHES B SEWAGE INPUTS ST. OYSTH, COLCHESTER & FINGRINGHOE DESIGNATIONS SSSI, NNR RECREATION USES SAILING, POWER BOATING, CANOEING, SAILBOARDING & WINDSURFING SHELLFISHERIES PYEFLEET CHANNEL, BATCHELOR SPIT, BENCH HEAD, THE NOTHE & HARBOUR ENTRANCE FISHERIES TRAWLING AND FYKE NETTING IMPORTANT BIRD SPECIES BRENTGEESE, SANDERLING, REDSHANK, DUNLIN & BLACKTAILED GODWIT
45
MAP 13 I COLNE ESTUARY USES AND INPUTS
I Colchester STW
COLCHESTER SHELLFISHERIES lv-V:vi I RECREATION I
I MARINA O Wivenhoe I I I I I
>/Q -
brightlingsea
PVe
Bouy 13
MERSEA ISLAND
y Batchelor Spit
The_ Nothe / W.Mersea STW I D 7 T l 8 BLACKWATER ESTUARY
The Blackwater estuary is the largest estuary in Essex, apart from the Thames. To the north of its mouth the Blackwater is joined by the Colne and to the south it is continuous with the Dengie flats. The Blackwater has two islands, Osea Island and Northey Island. It has many creeks, river channels and saltmarsh which provide a diversity of habitats.
Its remote position, great extent, variety of habitats and abundant supply of food make it very attractive for a great range of sea and shore birds, especially Brent Geese. Together with the Colne, Dengie flats and the Maplin Sands this site is one of the most important over wintering sites for wildfowl and waders in Western Europe.
Most of the intertidal area of the Blackwater estuary is mudflats, saltmarsh is not extensive and tends to occur in pockets, at present the saltmarsh is suffering from erosion.
A large proportion of the saltings have been reclaimed along the estuary shore, and much of this area has been converted into arable land.
The Blackwater Estuary tidal catchment has a population of 20,000 with the main centre of population at Maldon. There are a number of sewage effluents entering the estuary and its tributaries at West Mersea, Tiptree, Tollesbury, Maldon and the combined effluents from Chelmsford and Witham. The water quality is of NRA grade A standard, with a small section of grade B in the upper reaches.
The Blackwater estuary has many important shellfisheries, they are all oysterages apart from Thirslet Creek. The main areas are Goldhanger Creek, Salcott Channel and Tollesbury Fleet and were designated under the 1979 Shellfish Directive.
48 8.1 DESIGNATIONS (Map 14) The Blackwater estuary is proposed as part of the Mid-Essex Coast SPA and RAMSAR site. The Blackwater estuary NNR is situated on the north shore and combines the mud flats extending from Tollesbury Wick westwards to Gore Saltings, the intertidal area to the north of Salcott Channel, and the RSPB reserve at Old Hall Marshes. The National Trust own several areas of land on the Blackwater, the Essex Wildlife Trust manage Ray Island, which is owned by NT. The Blackwater SSSI covers the whole of the estuary excluding some of Northey Island and most of Osea Island, this is land that has lost its special interest since the last notification.
The Blackwater estuary is one of the largest estuarine complexes in East Anglia. Its mudflats, fringed by saltmarsh on the upper shores, support internationally and nationally important numbers of overwintering waterfowl. Shingle and shellbanks and offshore islands support a diverse population of nationally scarce plants and nationally important rare invertebrates, with 16 Red Data Book species and 94 notable and local species.
The Blackwater holds 4.7% of the world population of Dark bellied Brent Geese as well as supporting important numbers of Ringed Plover, Dunlin, Shelduck, Gadwall, Curlew, Teal, Grey Plover and Redshank. The estuary contains the largest area of saltmarsh in Essex, 1 103 ha, the fifth largest area in Great Britain. It provides refuge for many birds and invertebrates.
In the low marsh areas the nationally scarce Lax-flowered Sea- lavender, Limonium humile. can often be found interspersed among the more common species. Scarce saltmarsh grasses such as Stiff Saltmarsh-grass, Puccinellia rupestris. are also found. On the foreshore of West Mersea the county rarity Sea Spurge, Euphorbia paralias. has been discovered.
The saltmarsh vegetation supports rare moths and a rare green beetle as well as the specialist jumping spiders. The aquatic
49 invertebrate species associated with the ditch systems of the Blackwater's coastal marshes are very diverse. The larvae of the Red Data Book horsefly, Hybomitra expolicata. and the endangered Red Data Book water beetle, Paracymus aeneus r are found here.
8.2 USES (Map 15)
8.2.1 RECREATION: Leisure persuits cover the whole of the Blackwater estuary, there are over 1,000 moorings and a marina at Bradwell. Sailing, windsurfing, sailboarding, power boating, waterskiing and canoeing take place over parts of the estuary, as well as pleasure angling.
8.2.2 SHELLFISHERIES: The Blackwater has several commercially important shellfisheries. Goldhanger Creek, Thirslet Creek and The Nass have been designated under the E.C. Shellfish Directive 199 3. Both Goldhanger Creek and The Nass contain oysterages whereas Thirslet Creek contains a mussel shellfishery. At present The Nass has been graded at class B, and the other two are at class A.
Peewit Island, Tollesbury North and South, Salcott Channel, Little Ditch, and St. Peter's Flats have a shellfish grading of class B, except St. Peter's Flats which is class A. Cockles are also harvested at Buxey Sands at class B.
8.2.3 FISHERIES: Fyke netting for eels as well as digging for bait occurs along the estuary.
8.2.4 INDUSTRY: Industry is limited to boat building, repair yards and small engineering works. However on the south shore Bradwell Power Station imparts some limited local thermal effect on the estuary.
50 8.2.5 SEDIMENT EXTRACTION AND DREDGING: Only maintenance dredging occurs in the estuary, in the upper reaches.
8.3 INPUTS
8.3.1 EFFLUENTS: There are several sewage effluents affecting the Blackwater estuary. West Mersea has a current consent of 200SS, it only undergoes primary treatment and its quality is considered to be poor. Tiptree,.Tollesbury, Maldon and the combined effluents from Chelmsford and Witham STW all have full treatment. Apart from Maldon, the effluents are of marginal quality with respect to their consents, Maldon has satisfactory effluent quality. Tiptree has a current consent of 30SS/15BOD, Tollesbury of 40SS/30BOD and Chelmsford and Witham of 40SS/20BQD. The outfall pipe of the combined effluents is at Beeleigh falls, the head of the tidal river.
Bradwell Power Station discharges cooling water into the estuary at a rate 2290909 m3/d with a maximum temperature of 32°C.
8.3.2 RIVERS: The tidal limit of the Blackwater estuary is at Beeleigh falls in Maldon.
The Blackwater does not possess a discernable saline wedge. The freshwater catchment of the Blackwater/Chelmer includes towns such as Braintree, Witham and Chelmsford influencing water quality on these potable water supply rivers.
51 8.4 SUMMARY
BLACKWATER ESTUARY
NGR TL9507 GEOMORPHIC TYPE COASTAL PLAIN TIDAL TYPE MACROTIDAL TOTAL AREA ha 5184 INTERTIDAL AREA ha 3315 SHORELINE km 108 TIDAL CHANNEL km 21 AREA OF MUDFLATS ha 2600 AREA OF SALTMARSH ha 900 TIDAL LIMIT BEELEIGH FALLS POPULATION 20 000 NRA SURVEY CLASS A and B SEWAGE INPUTS WEST MERSEA, TIPTREE, MALDON, TOLLESBURY, COMBINED EFFLUENTS INDUSTRIAL INPUTS BRADWELL POWER STATION DESIGNATIONS SSSI, NNR RECREATION USES SAILING, CANOEING, WINDSURFING POWERBOATING, WATERSKIING SHELLFISHERIES GOLDHANGER CREEK, TOLLESBURY NORTH & SOUTH, THIRSLET CREEK, THE NASS, ST. PETERS FLATS, BUXEY SANDS, SALCOTT CHANNEL & LITTLE DITCH IMPORTANT BIRD SPECIES BRENTGEESE, SHELDUCK & DUNLIN
52 BLACKWATER ESTUARY
DESIGNATIONS WEST MERSEA
SITE OF SPECIAL SCIENTIFIC INTEREST ' \ Fleet NATIONAL NATURE RESERVE t- ’> ^ . / RIVER BLACKWATER
Tollesbury /
ih Falls tn sBradwell Power Station w \ / Pewit Isl^njd f V I Thirslet Creek t/Vf Goldhanger"Creek MALDON
x ' / f I / / / \V i
Mayl andsea BLACKWATER ESTUARY USES AND INPUTS
ford and Witham STW SBradwell Power Station
SHELLFISHERIES
RECREATION V / A
MARINA O
SEWAGE TREATMENT WORKS I ~ > 1 9 CROUCH ESTUART
The Crouch estuary is a long, narrow coastal plain estuary with narrow intertidal mudflats flanked by reclaimed land and saltmarsh in its upper reaches. It occupies a shallow valley between two ridges of London clay in south Essex. The tidal section is 20 km long and forms a narrow estuarine habitat.
Much of the river channel is used intensively for recreational activities and is of relatively little value for wildlife. Despite this the estuary is important in supporting several internationally important wintering wildfowl and an extensive bed of Slipper Limpets, Crepidula fornicata. Slipper Limpits are considered to be a pest in the estuary as they compete with the more commercial oysters.
Since the Middle Ages the shore of the Crouch has been embanked to provide grazing and arable land. There are a few small areas that have been left as saltmarsh, including Woodham Fenn and the upper sections of Paglesham Pool. Other saltmarshes have formed due to breaches in the sea wall including Bridgemarsh Island, Brandy Hole and North Fambridge Marsh, these have all developed during the course of this century.
The Crouch estuary catchment has a population of 15,000 with centres of population at Burnham, Hullbridge and Woodham Ferrers. Sewage effluents enter the Crouch estuary at Burnham, South Woodham, Wickford and Rayleigh West. The Crouch estuary has been given an NRA classification of grade A and B with respect to its water quality.
There are three oysterages on the Crouch; Althorne Creek, Purleigh Shawl and the Outer Crouch. These are extensively used.
55 9.1 DESIGNATIONS (Map 16)
The Crouch-Roach estuary is a proposed SPA and RAMSAR site. 939 ha of the Crouch estuary is covered by the River Crouch Marshes SSSI. The Dengie Flats and Foulness also come under the designation of an SSSI. Essex Wildlife Trust also have several reserves within the SSSI boundary. Bridgemarsh Island is a Beperate SSSI due to its large area of saltmarsh and intertidal mud. With the exception of Dengie it is the largest unit of continuous saltmarsh in Essex.
The reasons for notification include the range of plant species found on the saltmarsh including the uncommon Lax-flowered Sea- 1avender, Limonium humile, and Shrubby sea-blite, Sueda vera. At Lion Creek a rare butterfly, the Brown Argus, Aricia aaestis. can be found.
Where reclaimed land has not been used for intensive agriculture grazing marsh is found, it is increasingly becoming less common as a recent survey suggests that 80% of saltmarsh in Essex has been lost due to drainage and conversion to arable land. On the marsh occasional uncommon flora is found, such as the Mousetail, Myosurus minimus.
The complex of saltmarsh, grazing marsh and intertidal habitats is of major importance to birds, especially as feeding and roosting sites for wildfowl. Wigeon, Teal and Pintail are found in internationally important numbers. Dark-bellied Brent Geese overwinter on this estuary as well as the other estuaries in Essex.
9.2 USES (Map 17)
9.2.1 RECREATION: The amenity value of this estuary is high, it has three marinas
56 and over 200 moorings, as a result the estuary is widely used for sailing. Windsurfing and canoeing take place over most of the estuary whereas power boating and water skiing are controlled by bye-laws.
9.2.2 SHELLFISHERIES: The Crouch estuary supports three oysterages at Althorne Creek, Purleigh Shawl and the Outer Crouch. Under the E.C. Shellfish Hygiene Directive 1993 Althorne Creek and Purleigh Shawl have been given a class of B, and the Outer Crouch class C. Designations of these fisheries also took place under the 1979 Shellfish Directive.
9.2.3 SEDIMENT EXTRACTION AND DREDGING: Maintenance dredging and commercial terrestrial aggregates extraction occurs along parts of the lower Crouch estuary.
9.3 INPUTS
9.3.1 EFFLUENTS: There are four sewage effluents that influence the Crouch water quality; Burnham, South Woodham, Wickford and Rayleigh West. All these sewage treatment works have full treatment and are considered to have a satisfactory effluent quality with respect to their current NRA consent conditions. Burnham has a current consent of 40SS/30BOD, Wickford has a consent of 45SS/22BOD and Rayleigh West has a consent of 5OSS/3OBOD/4OAMMONIA.
9.3.2 RIVER: The tidal limit of the Crouch is at Memorial Park and the estuary does not possess a detectable saline wedge.
The freshwater catchment is largely urban areas with a small proportion of arable agricultural area.
57 9.4 SUMMARY
CROUCH ESTUARY
NGR GEOMORPHIC TYPE COASTAL PLAIN TIDAL TYPE MACROTIDAL TOTAL AREA ha 4000 INTERTIDAL AREA ha 2000 SHORELINE km 85 TIDAL CHANNEL km 30 AREA OF MUDFLATS ha 800 AREA OF SALTMARSH ha 250 TIDAL LIMIT MEMORIAL PARK POPULATION 15 000 NRA SURVEY CLASS A SEWAGE INPUTS RAYLEIGH WEST, BURNHAM, WICKFORD, SOUTH WOODHAM DESIGNATIONS SSSI RECREATION USES SAILING, CANOEING, WINDSURFING, POWER BOATING & WATER SKIING SHELLFISHERIES OUTER CROUCH, PURLEIGH SHAWL & ALTHORNE CREEK IMPORTANT BIRD SPECIES WIGEON, TEAL, PINTAIL & DARK- BELLIED BRENT GEESE
58 CROUCH AND ROACH ESTUARY DESIGNATIONS
^ ^Fambridge
<0 Battlesbridge
SITE OF SPECIAL SCIENTIFIC INTEREST ^ , CROUCH AND ROACH ESTUARY > *D USES AND INPUTS 10 ROACH ESTUARY
The main part of the Roach estuary is long and narrow extending 14 km from its mouth in the lower Crouch estuary to Rochford. The Roach estuary only has an average width of 250 m and as a result only 60 ha of intertidal mudflat is exposed at low water.
The estuary flows through a network of creeks where small areas of saltmarsh have developed. Within these saltmarshes there is a good diversity of saltmarsh communities.
Foulness lies on the north shore of the Thames estuary between Southend in the south and the Roach to the north. It comprises extensive intertidal sand-silt flats, saltmarsh, beaches, grazing marshes, rough grass and scrubland. The flats are of international and national importance as winter feeding grounds for twelve species of wildfowl and waders. The complex matrix of habitats also supports an outstanding assemblage both of plants and invertebrates with some species being nationally uncommon or rare.
Empty cockle shells are washed up at Foulness Point to form the most extensive shell beach in Britain.
The Roach tidal catchment has a population of 7,000 with the main centre of population at Rochford. The sewage effluents that affect the Roach estuary are Rochford STW and Rayleigh East STW. The current quality of the Roach estuary is good with respect to the NRA classifications and is classified as grade A and B.
The Roach estuary has several shellfisheries which are all designated under the EC Shellfishery Directive 1993 and 1979. They include oyster, mussel and cockle beds at Paglesham Pool, Dunhopes and Middleway.
61 10.1 DESIGNATIONS (Hap 16)
The Roach estuary is part of the Crouch—Roach estuary proposed SPA and RAMSAR site. Foulness is a designated SSSI which covers the southern shore of the Roach estuary, the creeks to the south of the estuary, Foulness sands and Maplin Sands. The area supports four species of wildfowl at nationally important levels; Shelduck, Shoveler, Wigeon and Teal. Dark-bellied Brent Geese occur in internationally significant numbers. Of the waders, Curlew and Dunlin occur in nationally important numbers and Bar tailed Godwit, Grey Plover, Knot, Redshank and Oystercatcher occur in internationally important numbers. The shellbeach supportb a nationally important colony of Terns and Black-headed gulls.
There are number of uncommon plants associated with the saltmarshes including Borrers Saltmarsh-grass, Puccinellia fasciculata. Lax-flowered Sea-lavender, Limonium humile, and Annual Beard-grass, Polypogon monspeliensis. At Gunners Park, unimproved grassland has developed over relict sand dunes and in consequence supports a flora which is unique in Essex.
Foulness is also of prime importance for its invertebrates. There are no less than 83 species listed as of notable occurrence or nationally rare, including such Red Data Book species as the Scarce Emerald Damselfly, Lestes dryas. the beetle, Tachys scutellariB, and the fly Stratiomys lonaicornis.
10.2 USES (Map 17)
10.2.1 RECREATION: The Roach estuary is used quite extensively for leisure activities. It has approximately 100 moorings and consequently sailing is widespread throughout the estuary. Paglesham Creek suffers considerable problems of disturbance from water sports such as water skiing.
62 10.2.2 SHELLFISHERIES: There are three shellfisheries in the Roach estuary, Paglesham Pool contains oysters, mussels and cockles and these have been graded as class A/B, Dunhopes contains mussels and cockles and is of class C for mussels and B for cockles, The Middleway has a cockle bed which is of class C. All three sites have been designated under the EC Shellfish Hygiene Directive 1993 and the 1979 Shellfish Directive.
10.3 INPUTS
10.3.1 EFFLUENTS: The Roach is principally affected by two sewage effluents, both have tertiary sewage treatment and, at present, are considered to be of satisfactory quality with respect to their current NRA consent standard. The sewage treatment works are at Rochford and Rayleigh East. The current consent for Rochford is 60SS/35BOD and for Rayleigh East is 30SS/15BOD.
10.3.2 RIVERS: The tidal limit of the Roach estuary is at Broomhill.
No saline wedge has been detected in the estuary. The freshwater catchment is largely urban and consequently the River Roach has a large proportion of treated effluent as its base flow.
For all estuary introductions: See Appendix 1 - Full summary table Appendix 2 - Statutory Nature Conservation Sites Appendix 3 - Main sewage inputs into estuaries Appendix 4 - Trade effluent inputs Appendix 5 - Shellfisheries present on the estuaries Appendix 6 - EC Shellfish Hygiene Directive 91/492/EEC
63 SECTION B]
WATER___QUALITY TRENDS
10.4 SUMMARY
ROACH ESTUARY
NGR GEOMORPHIC TYPE COASTAL PLAIN TIDAL TYPE MACROTIDAL TOTAL AREA ha 1020 INTERTIDAL AREA ha 600 SHORELINE km 42 TIDAL CHANNEL km 14 AREA OF MUDFLATS ha 300 AREA OF SALTMARSH ha 120 TIDAL LIMIT BROOMHILL POPULATION 7 000 NRA SURVEY CLASS A SEWAGE INPUTS ROCHFORD & RAYLEIGH EAST DESIGNATIONS SSSI RECREATION USES WATER SKIING, SAILING & WINDSURFING SHELLFISHERIES PAGLESHAM POOL, DUNHOPES & MIDDLEWAY IMPORTANT BIRD SPECIES SHELDUCK, SHOVELER, WIGEON, TEAL, DARK-BELLIED BRENT GEESE, REDSHANK, CURLEW & DUNLIN
64 B] CHEKtGAI. HATER QUALITY TRENDS
It should be noted that some graphs have gaps in the data during the 1980's, this is due to data being archived on inaccessble tape. Earlier data is recorded on paper and subseguent data is held on CDPS and L1MS.
Only three or four representative sample points have been highlighted for each estuary, to illustrate the overall, chemical water guality. The full list of sample points and freguency of sampling can be seen in Appendix 7.
1 BLYTH ESTUARY
1.1 Historical Events from E.Suffolk and Norfolk Rivers Authority Annual Reports 1966-1974
1969 New sewage works at Halesworth completed resulting in a good quality effluent.
1971 'Le Grice' turkey processing plant polluted the upper reaches of the River Wang as a result it was forced to close down.
1972 Bernard Matthews turkey processing plant established on old 'Le Grice' site.
1973 Prosecution of Bernard Matthews for polluting effluent entering the River Wang.
Historically the quality of the Blyth estuary has, in general, been good.
65 1.2 Interpretation of Chemical Trends
Both Collins Island and Wolsey Sluice are NRA survey points. DO and ammonia results show that the estuary is unpolluted and the water is of good quality. BOD levels show little evidence of eutrophication and E. coli results suggest that there may be some influence on the estuary due to the large bird population present particularly in the winter months (Fig 1 & 2).
Wolsey Sluice is mainly fed by the River Wang at ebb tide and low water periods, as the sluice is tide locked at high water. The samples are taken at high water only, so to gain a clearer picture of the overall quality, and effects of Bernard Matthews factory, sampling over a tidal cycle would be necessary. However, at present, the effects of the factory appear to be minimal in the estuary (Fig 2).
Bailey Bridge is sampled monthly, it is approximately 10 m below the treated effluent of Southwold STW. The slightly elevated BOD, ammonia and E. coli values, compared with the other two sampling points, can be attributed to .this proximity to the sewage treatment works (Fig 3 & 4).
Flesh samples from the oysterage at Wolsey Creek are of class B quality. The oysters are uv treated before they are sold but the oysterage is of limited commercial importance (Fig 5).
(See Map 18 for location of sample points) FIG 1 SAMPLE POINT CODE - BIBLY060
BLYTH ESTUARY BLYTH ESTUARY COLLINS ISLAND COLLINS ISLAND Ammonia BOD
E re 0c E 1
Date Date
BLYTH ESTUARY BLYTH ESTUARY COLLINS ISLAND COLLINS ISLAND DO E . coli 100 99 98 , „ * 97 O 96 ° 95 94 93 92 J 01/07/89 01/07/90 01/07/91 30/06/92 Date Date
67 FIG 2 SAMPLE POINT CODE - BIBLY064
BLYTH ESTUARY BLYTH ESTUARY WOLSEY SLUICE WOLSEY SLUICE Ammonia BOD
E « c 0 E 1
Date Date
BLYTH ESTUARY BLYTH ESTUARY WOLSEY SLUICE WOLSEY SLUICE DO E. coli
o CO Date Date m FIG 4 SAMPLE POINT CODE - BIBLY070
BLYTH ESTUARY BAILEY BRIDGE DO
Date
BLYTH ESTUARY BAILEY BRIDGE E. coli 40000 - 35000 | 30000 o 25000 ^ 20000 o 15000 s 10000 m 5000 0
70 FIG 5 BLYTH AND ORE/ALDE SHELLFISH SAMPLES ORE/ALDE - BUTLEY CREEK OYSTER FLESH SAMPLES <4 nnr\nn ...... £ CO p# 1nnnn 1 uuuu - O \l w IUUU \ \ 8 100 A / t-R if P \ ^ ^ CIUSbA uj o> 10 o 1 01/03/91 29/02/92 01/01/93 Date ORE/ALDE - STONEYDITCH CREEK MUSSEL FLESH SAMPLES Date i -8' iia b l ;OV< Pika 7 b\ Green B o ttc - rr^»-=f White Hou»? ■ : r ~ r C h u rc h h 1 -*— >‘ kr?2>l > Red House Rou 5 ^ East Elms Fm \V» ! brook Fm - \ W a B ro BLYTH ESTUARY / X J cAwood Fm\ 16 Wangford Ip; \ > \j>< iv\P%\ | /------IP \s ' SAMPLE POINTS a'b /S' Jay s Fm "X3 < tRevdon, ^Revaon. - ^ 3 L W o o d , ^ F m ’\ _ \ -»i_ / r«v U ? \ (— ^ _— J~ 00 C f dill n , Th o E lm su -^------,.• ,.---v ■ ^ _ l _ c Reydonl ■ ( "W^- y II /rM^tean ,F rr i; } ; q • .^'Smear \« / ® ; / ry / [ Wangford Hill >iaU 'Fm • A-fcJ 4 ' ' .J2L f a* ^ / W 11 c is to n ? t;J - ;/ t ] » \ \ ^ — f ^ r m r\ n vr>~ ^'■Reydoi ~. " / :/ /1 . „ /A Reydon^^n— i , j£4=4ss^ i ^ o 2 /’H ill F r n ^ y .y ___ M a rdle JJ. G ra ng e fSme3r i s L C C ^ ^ P Church ~~ Sand Fm o n\7 >V>o Park'i ■ . Lime Kiln' San 12 (sOjButcamp Ho r f * / / * • » V, /■■■■■ ■ ■ , / BIEM2 4. 1 • c//> Oc* oS ‘ * |Y. ■■:" ,* '* ~ B^ythbufgR^ifc^, />\. i itSSPSfikn'f F°yert . >i i, _✓ V-^EastwoqarSuge^'r ■fi t com v ■ a ■ irrfr? w 6 • “J - VJ'.^’■'"'7 1 r-s’ T."' rriimnli ~ /^Tin I ■ \ m 0 i V. ^1*3 I ' ii ■■■>. 387 ‘ i * •“ iFa^t! Sh^fm WestwocK iLodg ' CpverL^VNtjde\kk{ * - W p .. ^ 1 ' r “ ■ ' “?C'<^ " - ' ., ^ n9,eH,(iV/’'y«V;- Gfeot f\(L^< ^ /• ' P %Fpji HiH,...:.. ■’ - .. .' o:. - - ■ v-Jo— /.. -t \ CS ■ Nifvrflfcliijlit',,/ 1 r v . 2 ORE/AIJ)E ESTUARY 2.1 Historical Events from E.Suffolk and Norfolk River Authority Annual Report 1966—1974 1967 - Effluent from Saxmundham STW contained high volumes of suspended solids. 1969 - Silage pollution in the estuary resulted in fish deaths leading to a prosecution. 1971 — The new Aldeburgh STW did not perform to expectations. Framlingham and Saxmundham STW, which input into the River Ore showed signs of deterioration. 1972 - Saxmundham STW was abandoned. 1974 - Saxmundham STW was replaced by regional 'Benhall' Scheme. 2.2 Interpretation of Chemical Trends Iken Cliffs shows good quality with respect to E. coli and DO however, there is some evidence of eutrophication in the BOD results. There is no effluent input in the vicinity and the freshwater flow from the Ore and Aide is unpolluted (Fig 6). Orford Quay shows ammonia level improvements since the 1980's and within the last few years all parameters show a satisfactory water quality. The discharge from Orford STW appears to be of good quality and is not affecting this point (Fig 7 & 8). 73 Havergate Island is below Orford STW and shows excellent quality. The E. coli levels are exeptionally low partly due to dilution given by the deep water channel present at t-his sampling point (Fig 9). Butley oysterage which is in a creek off the main estuary is sampled frequently by land as the oysterage is of commercial importance. The quality is variable due to eutrophication effects, but in general the BOD and E. coli levels are low. The odd peak in E. coli flesh values is thought to be due to boating activities and excessive use of the estuary by wildfowl. Under the 1993 Shellfish Hygiene Directive, Butley Creek is classed as a class A shellfishery. Stoneyditch is not as clean as Butley Creek as it is situated nearer to the Orford sewage works and it borders on class A/B. It is a small non-commercial mussel shellfishery (Fig 10, 11 & 5). (See Map 19 for location of sample points) 74 FIG 6 SAMPLE POINT CODE - BIOAE020 ORE/ALDE ESTUARY ORE/ALDE ESTUARY IKEN CLIFFS IREN CLIFFS Ammonia BOD 3 E 5 .2 E oc Q O E DO CO o CO CO o CO Date Date ORE/ALDE ESTUARY ORE/ALDE ESTUARY IKEN CLIFFS IKEN CLIFFS DO E. coli o CM 03 5 - 5 CO CO s s Q s s S o CO o o o CO © Date Date 75 FIG 7 SAMPLE POINT CODE - BIOAE040 ORE/ALDE ESTUARY ORFORD QUAY Ammonia o o ocooooco Date FIG 8 SAMPLE POINT CODE - BIQAE040 ORE/ALDE ESTUARY ORFORD QUAY DO Date 77 FIG 9 SAMPLE POINT CODE - BIOAEQ55 ORE/ALDE ESTUARY ORE/ALDE ESTUARY HAVERQATE ISLAND HAVERGATE ISLAND Ammonia BOD Date Date ORE/ALDE ESTUARY ORE/ALDE ESTUARY HAVEROATE ISLAND HAVEROATE ISLAND DO E. coli 120 100H * 80 o 60 5 Q 40 uo 20 qI m r- 00 os o 00 oo a> o o8 s o o 8 O 8 CO Date Date 78 FIG 10 SAMPLE POINT CODE - BIQAE050 ORE/ALDE ESTUARY BUTLEY OYSTERAGE Ammonia Date ORE/ALDE BUTLEY OYSTERAOE BOD Date 79 FIG 11 SAMPLE POINT CODE - BIQAE050 ORE/ALDE BUTLEY OYSTERAGE DO Date 80 3 DEBEN ESTUARY 3.1 Historical Events from E.Suffolk and Norfolk River Authority Annual Report 1966-1974 1966 - Woodbridge and district STW completed resulting in good quality effluent. 1968 - Kesgrave and district STW phase I and III extension completed. Historically the quality of the Deben estuary has been good. 3.2 Interpretation of Chemical Trends Woodbridge Quay is upstream of Martlesham Creek and this point shows variable ammonia values, possibly due to the influence of Melton STW. DO values are satisfactory however/ BOD values show signs of eutrophication particularly in recent years (Fig 12 & 13). Waldringfield Quay is sampled frequently as it is below all the effluent inputs. There is more eutrophication evident in this stretch frequently reaching a BOD value of 6 mg/1. Apart from being below effluent inputs this site is below a large slow flowing stretch of water. Ammonia has improved since the mid 80's. The E. coli average values are exceptionally good in this area with values below 50, this is probably due to natural die off (Fig 14 & 15). Bawdsey Ferry at the mouth of the estuary has excellent quality with an improvement in quality since the mid 80' s for no apparent 82 reason (Fig 16 & 17). Shellfish flesh samples at Methersgate Quay show that it was class A throughout 1991-92 but during the early part of 1993 the E. coli values are tending towards the classification of class C. The shellfishery at Methersgate Quay was not of great commercial importance but it has plans for development. The mussel samples show contamination from Woodbridge and Melton STW and only occasional gathering is undertaken (Fig 18). (See Map 20 for location of sample points) 83 FIG 12 SAMPLE POINT CODE - BIDEB110 FIG 13 SAMPLE POINT CODE - BIDEB110 DEBEN ESTUARY WOODBRIDGE QUAY DO 120 100 jje 80 O 60 o 40 20 com (Dco oo goCO OJoo Oa> t-a> OJO) oh» h-o o oq5 o o o o<3 o oocooooco Date DEBEN ESTUARY WOODBRIDGE QUAY B . coli Date 85 I 1 SAMPLE POINT CODE - BIDEB130 FIG 14 BOD mg/1 Ammonia mg/1 o o o o k> ^ a> op -*> 01/07/85 01/07/86 01/07/87 30/06/88 1° £2S n 0 n 8 * Os ^u HM O 1 »S » lif B 3 01/07/89 B I s 01/07/90 01/07/91 30/06/92 FIG 15 SAMPLE POINT CODE - BIDEB130 DEBEN ESTUARY NALDRINOFIELD QUAY DO 140 ? ? ^ 3 ^ ^ ^ 3 O O O CO O O O CO Date 87 FIG 16 SAMPLE POINT CODE - BIDEB150 DEBEN ESTUARY BAWDSEY FERRY Ammonia Date DEBEN ESTUARY BAWDSEY FERRY BOD 1 E o mo Date 88 FIG 17 SAMPLE POINT CODE - BIDEB150 DEBEN ESTUARY BAWDSEY FERRY DO Date DEBEN ESTUARY BAHDSEY FERRY E* coli Date 89 FIG 18 DEBEN SHELLFISH SAMPLES DEBEN - METHERSGATE QUAY MUSSEL FLESH SAMPLES Date 90 ------< 2 ^ S 'H o o r.dq*V'1'*'0 r map 20 Woodb' • _• DEBEN ESTUARY ■ w# »i * ■ - -'v.;'■'?«* ’ ‘ H'iv/v24 ^ iMartlesn^m f : whip™ -j /N*UI« H ill US u Wa.rf.^g^l,, - ^ j Q |75nne,-^ P«it|iwee LodgeIh*c iv White'-., \\ o H u ll V ' 4 . 4 ' f/ j \i ; "''Wo- 5 fmiO*- • r^v «> •*- i f < - ’ Sndnlii 2J — Mpmley^ lT43fo £ N^w boSSsfip”V..H.^ u r ^ wH^' f'\ ^ 0 I ^ ' V 4 :>:«•*! » ^ • f^TJ Ri^TJhol r 1 Atdertan Walk: r. i :i- \ " J & r Sc “ •! ...p- tSJLBuckiesham ■•75 K broke ( V V- - vj i / ■ v V\ C3 t/‘ \AV c.oi, KirtonH?iSC;— i 'Cbv o’® Rl'O Houit lfz , ■taj • I i } f atVKnn^m . ^ s “|S;K Mor„en. '^alk^rrfiam^ <« f.' ;-. End r , . m 1 e v £ : ^ Marshes / yTJ £| Poml .....,: / * m J * i » • w 4 ORWELL ESTUARY 4.1 Historical Events from E.Suffolk and Norfolk River Authority Annual Report 1966-1974 1966 - A marked evidence of pollution is noted from Ipswich sewage works and industrial effluents, particularly from the sugar beet factory from September to February. 1967 - Modifications to Cliff Quay STW completed but still caused pollution. 1969 - Chantry STW produced good quality effluent and the quality of the wider estuary was satisfactory. 1970 - Sproughton STW showed great improvement and further expansion is planned. Cliff Quay STW is still polluting and began, sedimentation and sludge disposal. 1972 - Maltings at Stowmarket caused pollution and led to prosecution. British Sugar extended their discharge pipe to deeper water. 1973 - Leaks of oil from British Rail were stopped with a new oil interceptor and fitting an impervious plastic membrane under the track in the station area. 1974 - Sugar beet waste polluted the port area. 92 4.2 Interpretation of Chemical Trends Poor quality is noted at Lock gates frequently. The variability of quality if partially due to the fact that the site is sampled at all tidal states. There does not however appear to be any significant improvement since the mid 80's. At lock gates there is the influence of British Sugar, a tidally controlled discharge, Pauls Maltings and until recently Burtons. This has resulted in values of ammonia being between 1-1.5 mg/1 and BOD values of between 4 and 6 mg/1. This sampling point is also influenced by the effluent from Cliff Quay Sewage Treatment Works which is untreated. The DO levels are the most significant parameter at this site with concentrations of 30% recorded frequently (Fig 19). The graph of Ipswich sewer outfall (Fig 20) clearly illustrates the chronic pollution that existed in the '60's and '70's with BOD values between 40 and 140 mg/1. It has improved quite clearly since then during the '80's and '90's but the values are still not acceptable. Wool vers tone Marina is much less polluted than lock gates due to its distance downstream and the diluting effects of the estuary. However, some high ammonia values have been recorded with a trend of quality deterioration in recent years. Little signs of eutrophication are noted with the Orwell estuary (Fig 21). Heavy metal analysis is carried out at this sample point, and copper values appear to exceeded the annual average limit for the last four years. Other metals are not causing problems, although some zinc results appear high. These high values of copper are in part probably due to the trade discharge at Cliff Quay Sewage works, but also the extensive use of the Orwell estuary in recreational boating pursuits. Since TBT based antifouling paints were banned, copper antifouling points are used and this may add to the elevated copper values experienced at this site 93 (Fig 22). Collimer Point is influenced by Harwich, Dovercourt and Felixstowe effluents, however, their effects are minimal and the water quality at this site is satisfactory (Fig 23). (See Map 21 for location of sample points) 94 FIG 19 SAMPLE POINT CODE - BIQRW040 ORWELL ESTUARY ORWELL ESTUARY BT LOCK OATES BY LOCK OATES Ammonia BOD 14 12 T 10 E 8 g 6 g 4 2 U) CD r-» 00 a> 0 CM 00 $0 90 00 oo 01 o> g> CO co 3 3 3 o s 3 s 5 co o rt CO o CO Date Date ORWELL ESTUARY ORWELL ESTUARY BY LOCK GATES BY LOCK OATES DO E. coli , 120 100 * 80 O 60 Q 40 20 90in 90CD 00 oo00 ooa> o>o qi a> 95 FIG 20 IPSWICH SEWER OUTFALL 1967 - 1973 Year ANNUAL AVERAGES ILLUSTRATED IPSWICH SEWER OUTFALL 1987 - 1992 AMMONIA 140 BOD 120 100 80 I E o 8 60 «=c 09O I 40 200- 0* 1987 1988 1989 1990 1991 1992 Year 96 FIG 21 SAMPLE POINT CODE - BIORWIOO ORWELL ESTUARY ORWELL ESTUARY WOOLVERSTONE MARINA WOOLVERSTONE MARINA Ammonia BOD 16 14 *5.f 12 10 8 6 00 4 2 CO o> o CM m 00 o> o CN CO 00 O i co CO 00 00 at a> oCO s s s osCO s I oCO s s s oCO T“ CO o CO o CO o ?) Date Date ORWELL ESTUARY ORWELL ESTUARY WOOLVERSTONE MARINA WOOLVERSTONE MARINA DO E. coli 120 100 £ 80 O 60 V V i ° 40 20 m co CO 05 0 co co CO CO 00 a CO 97 FIG 22 ANNUAL METAL LEVELS AT WOOLVERSTONE MARINA ANNUAL COPPER LEVELS AT ANNUAL MERCURY LEVELS AT WOOLVERSTONE MARINA, RIVER ORWELL WOOLVERSTONE MARINA, RIVER ORWELL YEAR YEAR ANNUAL CADMIUM LEVELS AT ANNUAL ZINC LEVELS AT WOOLVERSTONE MARINA, RIVER ORWELL WOOLVERSTONE MARINA, RIVER ORWELL 250 200 P ---» — min —»— min I 150 ...... D ...... o ...... max 100 max ---+ -- mean Nl — +— mean 50 ...... --- 6 --- DAAIimit ------A------DAA limit 1989 1990 1991 1992 YEAR YEAR 98 FIG 23 SAMPLE POINT CODE - BIQRW120 ORWELL ESTUARY ORWELL ESTUARY COLLIMER POINT COLLIMER POINT Ammonia BOD % CO n Date Date ORWELL ESTUARY ORWELL ESTUARY COLLIMER POINT COLLIMER POINT DO E. coli co CO Date Date 99 ■KKR&iar i 5 fX-Vo-a ""•" .r r r r . - - r -1^"-* -V?.' * {r & * \V . i* v V» > ^ ------\ y ’ - - ^ ^ P o l r Mill ^ Brook'Mill */SS S H F " r-'O; S ORWELL ESTUARY r is SyP:^.: SAMPLE POINTS ;*;A I.’ « \ ^ 1 \\ J t . , 0'M relt VV £ 42? '•_ Orv.«(l P»'V -BIQRW120 \ . vy \ woo(jij>na? , V / • ' * attings^lone ,~*L— '‘-luSyS@ • ^ Uti.ngVo"*)..^^* \ ’ f *l.>Cf I ^ % 0H>O* ff*< '■ ■ - , \ V ^> , ~ . ■" v / . *-v—ia a r = K i *' c- *®523Lafi V , J i c y f 1 ■-;1bft* Va.t® Cl‘v ? Station'i »J2L JN_ .'' v«-A-JSfc * \2 ^9jy^HI 0 01 Jff ° 00 U ‘ /fm /“ £\|.'cWtl )/ itP ‘Lodg* ’ f' %~y / j y Loxveii ■ fj: . Holb>ook ■ L ?7 Si" * ^ .A\ " ' **9*HltvV^/.V*y *> . 1 j y--..#g>q (o X _( '•tfarksiead Ul/.. * Jr . “ Bl6RWj25^r >- ^ 5 "* 9 h ' • L j ^ ' jpj|j ,« J * > r Hill Houi#7JShOP frj>‘ Corner f N ith if Kpi fiejgmonl , .i.'io o/i ■ >• ■-{ * .1 V * H j| l .OH*l| E f « A i I <) n ^ B J y Shotley Gate8* ‘■V 1 ’>• '-I ^^The.(^pftjci'fSliiiiowt \ : r \% h a H li 0 i,i C^ frlm rfL "o rj ' N*»» BJORW 130 jm Slutt&n Ncis : .------I Oo**houtt Po*>ii f>Atk -<\0* 0“*> ...... b i o r « M ® if/, -■ ------i ; — ------sr— n m > . o-vf.w^olv 5 STOUR ESTUARY 5.1 Historical Events from Esses River Authority Annual Report 1953-74 1958 Trade and sewage effluent caused pollution between Brantham and Mistley. The estuary was relatively clean below Mistley. 1963 Continued pollution in upper reaches and restriction was placed on any further developments until the area sewage scheme has been provided. 1964 Discharge of settled sewage from Parkeston STW caused pollution to the Ramsey River. 1968 The Stour, which was previously affected by phytoplankton growths, was cleaner, although nitrate values were still high. Apart from the effluents at Parkeston and Harwich the water quality was satisfactory. 1971 Brantham STW was completed. 1974 Northern Area STW connecting Mistley and Manningtree was completed. 1975 Parkeston STW connected to Harwich guard outfall. 5.2 Interpretation of Chemical Trends At Manningtree Sailing Club a deterioration in ammonia since the 101 1980's is apparent. This may possibly due to Manningrtree STW taking additional loading. However, BOD levels have improved and any fluctuations tend to be due to eutrophication (Fig 24 - 27). At Baltic Wharf, Mistley, ammonia shows a deterioration in the water quality. BOD has remained within a range of 4 - 8 mg/1 and is unlikely to improve until the effluent from Mistley Quay is treated since the maltings effluent is a large proportion of this discharge. No DO sag appears at this sample site (Fig 28 - 31). Wrabness Point shows some oxygen depletion but both BOD and E . coli are low and the water quality is satisfactory, as is the water quality downstream at Harwich Pier, with respect to all parameters (Fig 32, 33, 34 & 35). (See Map 22 for location of sample points) 102 FIG 24 SAMPLE POINT CODE - BISE1650 STOUR ESTUARY MANNINGTREE SAILING CLUB HARD Ammonia (Pre 1985) i. E 'E.5 o E CO CO CO CO CO CO CO CO <0 CO Date STOUR ESTUARY MANNINGTREE SAILING CLUB HARD BOD (Pre 1985) CD h- C; £ oCD oGO T— CO CO CO CO CO CO co CO CO CO Date 103 FIG 25 SAMPLE POINT CODE ■ BISE105O STOUR ESTUARY MANN I NOTREE SAILING CLUB HARD Ammonia Date STOUR ESTUARY MANNINGTREE SAILING CLUB HARD BOD % E o o CD Date 104 FIG 26 SAMPLE POINT CODE - BISE1650 STOUR ESTUARY MANNINOTREE SAILING CLUB HARD DO (Pre 1985) Date STOUR ESTUARY MANNINGTREE SAILING CLUB HARD E. coli (Pre 1985) 60000 E 50000 e 40000 30000 «*o 20000 10000 Lli 0 CO CO CO CO CO CO CO CO CO CO Date 105 FIG 27 SAMPLE POINT CODE - BISE1650 STOUR ESTUARY MANNINOTREE SAILING CLUB HARD DO Date STOUR ESTUARY MANNINGTREE SAILING CLUB HARD E . coli Date 106 FIG 28 SAMPLE POINT CODE - BISE12 STOUR ESTUARY BALTIC WHARF MISTLEY Ammonia (Pre 1985) Date STOUR ESTUARY BALTIC WHARF MISTLEY BOD (Pre 1985) Date 107 FIG 29 SAMPLE POINT CODE - BISE12 STOUR ESTUARY BALTIC WHARF MISTLEY Ammonia 0.6 5 05 E(0 0.4 0E 0.3 | 0.2 1 0.1 A i 14/11/84 29/03/86 11/08/87 23/12/88 07/05/90 19/09/91 31/01/93 Date STOUR ESTUARY BALTIC WHARF MISTLEY BOD 25 ■ 20 ■ f 15 § 10 00 5 n 1 r 14/11/84 29/03/86 11/08/87 23/12/88 07/05/90 19/09/91 31/01/93 Date 108 FIG 30 SAMPLE POINT CODE - BISE12 STOUR ESTUARY BALTIC WHARF MISTLEY DO (Pre 1985) Date STOUR ESTUARY BALTIC WHARF MISTLEY E. coli (Pre 1985) Date 109 FIG 31 SAMPLE POINT CODE - BISE12 STOUR ESTUARY BALTIC WHARF MISTLEY DO Date STOUR ESTUARY BALTIC WHARF MISTLEY E . c o l i 25000 20000 oE T*o 15000 o 10000 ui 5000 0 01/01/87 01/01/88 31/12/88 31/12/89 01/01/91 01/01/92 31/12/92 Date 110 T 1 o u BOD mg/l Ammonia mg/l ro O N) W -U o o o o o o 01/09/57 o -t ro o> ^ cn a> 01/09/57 01/09/58 01/09/58 01/09/59 01/09/59 31/08/60 31/08/60 01/09/61 01/09/61 01/09/62 01/09/62 01/09/63 01/09/63 31/08/64 31/08/64 01/09/65 01/09/65 01/09/66 01/09/66 01/09/67 01/09/67 f 31/08/68 31/08/68 01/09/69 01/09/69 01/09/70 01/09/70 01/09/71 01/09/71 31/08/72 31/08/72 >CO 01/09/73 2 01/09/73 TJ D 01/09/74 a 01/09/74 & §“ 01/09/75 “0 £ 01/09/75 o 31/08/76 31/08/76 01/09/77 o 01/09/77 o 01/09/78 01/09/78 m0 01/09/79 1 01/09/79 w 31/08/80 31/08/80 m0) 01/09/81 01/09/81 01/09/82 01/09/82 01/09/83 01/09/83 31/08/84 31/08/84 01/09/85 01/09/85 01/09/86 01/09/86 01/09/87 01/09/87 31/08/88 31/08/88 01/09/89 01/09/89 01/09/90 01/09/90 01/09/91 01/09/91 31/08/92 31/08/92 FIG 33 SAMPLE POINT CODE - BISE07 STOUR ESTUARY OFF WRABNESS POINT DO Date STOUR ESTUARY OFF WRABNESS POINT E. coli 400 350 300 250 200 uo 100150 ui 50 0 o CM CO to CD 00 o> o to m CD r** 00 05 £ 00 oo oo I oo 00 00 5» 5 § £ S m m in 2> §CD m in CD CDs in m 8 O o p o P p 1 i p P P P p p P O o p co co co CO CO CO o CO CO CO CO CO Date 112 FIG 34 SAMPLE POINT CODE - BISE03 STOUR ESTUARY HARWICH PIER Ammonia o^-fMco^intoh-oo os CO m s § 3 go 8 CO w in 8 § § o o 9 i r- r- T" CO CO CO CO CO O o CO CO o o CO CO CO Date STOUR ESTUARY HARWICH PIER BOD O i- CN CO in 113 FIG 35 SAMPLE POINT CODE - BISE03 STOUR ESTUARY HARWICH PIER DO % B QO co CO CO CO CO CO o CO CO CO CO CO Date STOUR ESTUARY HARWICH PIER E. coli 1600 e 1400 o 1200 ° 1000 800 ou 600400 uj 200 m 0 ■- OJ CO u> £ £ o om CO p *— CO CO o o CO CO CO CO o co CO CO CO CO Date 114 ^ •' \ '' \ .. / Ni:wliourr»i:J ') \ W n UJtfi X . ■ v W l v i;\\< ** * - :ir. \ ' " > • ■ • ’ ro “ V" - -v , :/ ro ,* 1 ■ > A. i«m« ^ ^ I !\. ^ -«•'3 r r 1 '»** / 7®^^viMir« w. - . - | ____ v.r.:“o /V t ! j£ton;/-£^ fNi ■ > r-- V' V '| > | r "r*’V'V. / .; .7 T ?” ‘ ^2\ £•:•- . : ' w '[‘-/[ f T ;,' -fifrv .";/ j 'Ui'-i' y- y ^ ^ x z p /•■ ■ / 5ji» .•’ . !t!l" W i U/. , - . . • V-*. . h ’ ■ • <•:• ’aL-.. rf s i r . . > ^ :'\n ..m ;:,'.l^' i’^Ji!^Jr'rt,l'«y b; f 1m „ VX - ’ Ai rfVlMru^TiJf;-u .,.b4 1 V O ' -V? 1 j!i'^S4i*N?'' Ctielmondi^lin^ „^...... ;x i. ■ ' < " V . I ',■• j - - • j f e ' f ■/ > v ; <>••., . v .. . .•■ • t |; *•;« • Hfluv ’ ‘-1 \ i,.U = '"' ••X\ vu.i^« ' ;Vv • u # H ■^psK'u** ^ 'y f\' \ - 'j '’-\ i 1 V. *v* t / t .■• .',*''.'V’;."-‘“'"''* * * "’ ^-iAl*■**1 *■>" ,'r'"*» \i '•' ■’t'<'llny\ ■' ».p1,\ 1 VV« M 'M § \ ‘ ! W v ' , ■ • ■% ’’ . • W - ' ' \V. E;*v.trt(>ri I”'^.j. ;’V / ■ ® f .. , ■■■■■'/ ^ ;,,...*y*s..op / f- ,» - •'•» Ciwn^if 4~ Y :V _ BISE02 ^ M h |a m w ■ c. x I Shot ley Gate BISEOf ' - — V ^ H 'A R U 0 U R ^ BISE03L.I^>"- .....*.... « ifcPix-! ! •" j Wt.»ba»’\s / •^9 .-^ Q S S O ^ ”’" i vh« 6.1 Historical Events from Essex River Authority Annual Report 1953-1974 1982 — TBT was discovered to be in high concentration at West Mersea oyster layings and Walton Backwaters. 1984 - The outfalls at Clacton and Harwich were improved by extension. 6.2 Interpretation of Chemical Trends The quality of Kirby Creek, East of Skippers Island is variable. The ammonia levels are on average 0.1 mg/1 and BOD values between 1 - 3 mg/1. It can be considered clean. The shellfish flesh results at this sample point show a classification of A/B. The NRA believe that quality over 1991 - 1993 has not deteriorated as has been thought by locals and the graphs illustrate this point (Fig 36, 37 & 43). The Twizzle off Titchmarsh Marina shows similar trends. More data is illustrated as this is a land based sampling point. There are no sewage discharges into Walton Backwaters and any fluctuations in BOD are probably due to eutrophication. However, there is an acidic discharge from the explosives factory, EXCHEM which has a limited deleterious effect. E. coli in shellfish flesh show a shellfish quality of between class A and B. This has not changed in the last decade. From the histogram of Dovercourt STW it can be seen that there has been minimal change in effluent quality. The quality of both shellfisheries should improve as Dovercourt outfall is abandoned in 1996/7 (Fig 38, 39, 40 & 43). 116 Saltfleet (Fig 41). Dovercourt (Fig 42). (See Map 23 for location of sample point) 117 FIG 36 SAMPLE POINT CODE - BIHW5010 WALTON BACKWATERS WALTON BACKWATERS KIRBY CREEK EAST OF SKIPPERS ISLAND KIRBY CREEK EAST OF SKIPPERS ISLAND Ammonia BOD % 02 E 0.15 CB oc 0.1 E 0.05 01/03 29/02 28/02 28/02 01/03 29/02 28/02 28/02 01/03 01/03 29/02 28/02 28/02 01/03 29/02 28/02 28/02 01/03 29/02 /83 /84 /85 /86 /87 /88 /89 /90 /91 /83 /84 /85 /86 /87 /88 /89 /90 /91 /92 Date Date WALTON BACKWATERS WALTON BACKWATERS KIRBY CREEK EAST OF SKIPPERS ISLAND KIRBY CREEK EAST OF SKIPPERS ISLAND DO Chloride 12 25000 10 % 20000 % 8 o 15000 E 6 O a§ 10000 Q 4 g 5000 2 01/03 29/02 28/02 28/02 01/03 29/02 28/02 28/02 01/03 01/03/8 29/02/8 28/02/8 28/02/8 01/03/8 29/02/8 28/02/8 /83 /84 /85 /86 /87 /88 /89 /90 /91 3 4 5 ^ t e 7 8 9 Date 118 FIG 37 SAMPLE POINT CODE - BIHW5010 HALTON BACKWATERS KIRBY CREEK E.coli in the water column 3000 g 2500 § 2000 £ 1500 o 1000 ui 500 0 01/01/83 01/01/84 31/12/84 31/12/85 01/01/87 01/01/88 31/12/88 31/12/89 01/01/91 01/01/92 31/12/92 Date •WALTON BACKWATERS KIRBY CREEK E .coli in the flesh of oysters Date 119 FIG 38 SAMPLE POINT CODE - BIHW1520 WALTON BACKW ATERS THE TWIZZLE OFF :riTCHMARSH Ammonia 0.25 ■ % 0-2 E to 0.15 I 0, | 0.05 n 01/05/82 01/05/83 30/04/84 30/04/85 01/05/86 01/05/87 30/04/88 30/04/89 01/05/90 01/05/91 Date WALTON BACKW ATERS THE TWIZZLE OFF 1 riTCHMARSH BOD 10 ii ■ 8 ■ 1 J E 6 O 4 m 01/05/82 01/05/83 30/04/84 30/04/85 01/05/86 01/05/87 30/04/88 30/04/89 01/05/90 01/05/91 30/04/92 Date 120 FIG 39 SAMPLE POINT CODE - BIHW1520 WALTON BACKWATERS THE TWIZZLE OFF TITCHMARSH DO 14 | 12 e 10 E 8 D O 6 Q 4 2 n 01/05/82 01/05/83 30/04/84 30/04/85 01/05/86 01/05/87 30/04/88 30/04/89 01/05/90 01/05/91 30/04/92 Date WALTON BACKWATERS THE TWIZZLE OFF TITCHMARSH Chloride 25000 ■§> 20000 E 0) 15000 1 10000 g 5000 n J ^ I 01/05/82 01/05/83 30/04/84 30/04/85 01/05/86 01/05/87 30/04/88 30/04/89 01/05/90 01/05/91 Date 121 FIG 40 SAMPLE POINT CODE - BIHW1520 WALTON BACKWATERS THE TWIZZLE E.coli in the water column 3500 3000 2500 2000 1500 o 1000 uJ 500 0 01/10/81 01/10/82 01/10/83 30/09/84 01/10/85 01/10/86 01/10/87 30/09/88 01/10/89 01/10/90 01/10/91 30/09/92 Date WALTON BACKWATERS TWIZZLE E.coli in the flesh of oysters Date 122 FIG 41 SAMPLE POINT CODE - BIHW13 WALTON BACKWATERS WALTON BACKWATERS WALTON CHANNEL SALT FLEET CONF. WALTON CHANNEL SALT FLEET CONF. Ammonia BOD 01/05/ 30/04/ 30/04/ 30/04/ 01/05/ 30/04/ 30/04/ 30/04/ 01/05/ 01/05 30/04 30/04 30/04 01/05 30/04 30/04 30/04 01/05 30/04 83 84 85 86 87 86 89 90 91 /83 /84 /85 /86 /87 /88 /89 /90 /91 /92 Date Date WALTON BACKWATERS WALTON BACKWATERS WALTON CHANNEL SALT FLEET CONF. WALTON CHANNEL SALT FLEET CONF. DO Chloride 12 25000 10 20000 8 va 15000 :r v E 6 ■e 10000 O o o 4 J= 5000 2 o 01/05 30/04 30/04 30/04 01/05 30/04 30/04 30/04 01/05 01/05/83 30/04/84 30/04/85 30/04/86 01/05/87 30/04/88 30/04/89 /83 /84 /85 /86 /87 /88 /89 /90 /91 Date Date 123 FIG 42 DOVERCOURT STW AMMONIA (average) 1985 1986 1987 1988 1989 1990 1991 1992 Dote DOVERCOURT STW BOD (average) 1985 1986 1987 1988 1989 1990 1991 1992 Date 124 FIG 43 WALTON BACKWATERS SHELLFISH SAMPLES WALTON BACKWATERS TWIZZLE OYSTER FLESH SAMPLES Date WALTON BACKWATERS KIRBY CREEK OYSTER FLESH SAMPLES Date 125 ^^Foulton • / \ § “MAP 23 x I t — ^ WALTON BACKWATERS SAMPLE POINTS Cfabknowe Spit i - A . Pye Sand______L-v vj/' x ^ /v - V Pennyhote Bay Otd-Moz«26 ■lip A 2' ]^£-v StaXy lA£,(«''• o __ BIHW9§f^OTPf^*. • 2 r \\\ I •oSySewage'’ ^90^ c>s^ Wks **aw # tj3£ , J THE 1 5 . 4 © J ^ ^ Jfw/ Nature T b iiW j s s o A i / G M t ! P ^ H , ;f lus V - -sk ^Vtt**V///CG Sta » \s» 3«P fe# f &' f$ Ma rt eltoalo wer WAL t o n - ^ iSl$PON-THE-NAZE Lifeboat Sta L'V'XV r. • ' u Ljl ■ r; Ccmv /ff^‘ 1 vSV c A) *1“ 0 0 [)0 24\^m \-*:' 1 ji 1 • __ 3? Fm .X tton /' \\ a \ V V r r . . *.1R \ 7 COLNE ESTUARY 7.1 Historical Events from Essex River Authority Annual Report 1953-1974 1958 - Below Colchester the estuary was polluted by sewage and trade effluents. Downstream of Wivenhoe the estuary becomes clean. 1961 - Indications showed that pollution was getting worse, pollution from Colchester STW was evident as far as Alresford. 1967 - Improved effluent quality from Haven STW. Chemically clean at Alresford but high bacterial content was noted during low. water as far as Brightlingsea where an additional polluting discharge of settled sewage occurs. 1971 - The upper estuary was grossly polluted by discharges from Colchester gas works and the overloaded STW. 1973 - Diversion of Wivenhoe STW to Colchester resulted in improvement but Brightlingsea was still not producing an effluent of satisfactory quality. 7.2 Interpretation of Chemical Trends Hythe Bridge shows a considerable improvement in BOD in the 19 9 0' s. Prior to that the BOD was reaching 15-20 mg/1 on occasions. The industrial discharges in the Hythe area that have now ceased, were the cause of these polluted conditions. DO 127 values are satisfactory but there is room for improvement, to achieve a class A/B designation. E. coli values are also high at this site. This point is significantly affected by Colchester Sewage Works effluent on the rising tide and there is minimal flow from the freshwater river into the estuary (Fig 44 - 47). Rowhedge Ferry shows the correlation between high ammonia levels at Colchester sewage works and Rowhedge Ferry. There was a particularly bad period during 1990 - 1991 with a much improved situation in 1992 - 1993. This highlights the need for an ammonia standard at Colchester .STW. DO shows poor levels throughout the year with it regularly dropping to 40%, E. coli levels are also regularly very high at this point. The estuary is used for many water contact sports and naturally the poor quality is of concern (Fig 48 - 53). Marsh Farm, Wivenhoe shows the most significant oxygen depletion in the estuary, this is due to the effects of Colchester STW. The ammonia levels are unsatisfactory although the E. coli values have decreased down the river length due to natural decay and dilution (Fig 54 - 57). Off Batemans Tower the water quality is generally satisfactory. It is much improved on the upper estuary with respect to all parameters. The nearby discharge at Brightlingsea does not appear to influence this point (Fig 58 - 61). Shellfish quality in this area is excellent considering the chemical quality of the estuary and the shellfishery in the main river borders on class A/B although parts of the Pyefleet Creek shellfishery is classed as 'A' under the 1993 E.C. Shellfish Hygiene Directive (Fig 62). (See Map 24 for location of sample points) 128 FIG 44 SAMPLE POINT CODE - BINE18 COLNE ESTUARY HYTHE BRIDGE Ammonia (Pre 1985) 00 CO to o o co CO CO Date .129 FIG 45 SAMPLE POINT CODE - BINE18 COLNE ESTUART HYTHE BRIDGE Ammonia % £ .9 ’Eo E 0 M U l i T u , . 01/04/85 01/04/86 01/04/87 31/03/88 01/04/89 01/04/90 01/04/91 31/03/92 Date COLNE ESTUARY HYTHE BRIDGE BOD 30 25 % 20 1 15 § 10 ru i)1/04/85 01/04/86 01/04/87 31/03/88 01/04/89 01/04/90 01/04/91 31/03/92 Date 130 FIG 46 SAMPLE POINT CODE - B1NE18 COLNE ESTUARY HYTHE BRIDGE DO (Pre 1985) j * . < r"-eocj>o*-c\icov»n COLNE ESTUARY HYTHE BRIDGE E. coli (Pre 1985) 300000 oE 250000 o 200000 150000 o 100000 ui 50000 0 ■mrT" CO o> ti £ m CD 9 o 8 T“ CO CO CO CO o CO CO o o CO CO Date 131 FIG 47 SAMPLE POINT CODE - BINE18 COLNE ESTUARY HYTHE BRIDGE DO Date COLNE ESTUARY HYTHE BRIDGE E. coli 300000 _ 250000 I 200000 £ 150000 8 100000 “ 50000 01/01/87 01/01/88 31/12/88 31/12/89 01/01/91 01/01/92 Date 132 FIG 48 SAMPLE POINT CODE - BINE13 COLNE ESTUAR7 ROWHEDOE FERRY Ammonia (Pre 1985) ■ E 4 .5c 3 o 2 I 0)0^* CM CO m r-cooor-cgcoTfmcor^eoajOT-cN to CO CO £0 1 CD CO CO % CO eo s o o O | o ppppopooooo s s CO o CO CO CO CO CO CO CO CO CO CO CO CO CO Date COLNE ESTUARY ROWHEDOE FERRY BOD (Pre 1985) Date 132 FIG 49 SAMPLE POINT CODE - BINE13 COLNE ESTUARY ROWHEDOE FERRY Ammonia 02/04/85 02/04/86 02/04/87 01/04/88 02/04/89 02/04/90 02/04/91 01/04/92 Date COLNE ESTUARY ROWHEDOE FERRY BOD Date 134 FIG 50 SAMPLE POINT CODE - BINE13 COLNE ESTUARY ROWHEDGE FERRY DO (Pre 1985) Date COLNE ESTUARY ROWHEDGE FERRY E. coli (Pre 1985) 250000 200000 150000 o 100000 ui 50000 0 CO to CD £ I £ £ 00 o p o p O p CO CO Date 135 FIG 51 SAMPLE POINT CODE- BINE13 COLNE ESTUARY ROWHEDOE FERRY DO 18 16 14 ! f « n . 01/04/85 01/04/86 01/04/87 31/03/88 01/04/89 Date COLNE ESTUARY ROWHEDGE FERRY E. coli 25000C •g 20000C " I P 15000C 1o 10000C W 5000C r I 01/01/87 01/01/88 31/12/88 31/12/89 01/01/91 01/01/92 Date 136 I 52 FIG BOD mg/l BOD OF ROWHEDGE FERRT AND COLCHESTER STW COMBINED EFFLUENT COMBINED STW COLCHESTER AND FERRT ROWHEDGE OF BOD Rowhedge Ferry a Colchester STW Colchester a Ferry Rowhedge 137 Date Ammonia mg/l AMMONIA CONTENT OF ROWHEDOE FERRY AND COLCHESTER STW COMBINED EFFLUENT COMBINED STW COLCHESTER AND FERRY ROWHEDOE OF CONTENT AMMONIA ..... Colchester STW — D— Rowhedge Ferry Rowhedge D— — STW Colchester Date FIG 57 SAMPLE POINT CODE - BINE10 COLNE ESTUARY OFF KARSH FARM WIVENHOE DO Date MEAN DAILY VALUE ILLUSTRATED WHEN MORE THAN ONE READING HAS BEEN TAKEN COLNE ESTUARY OFF MARSH FARM WIVENHOE E. coli 60000 _ 50000 | 40000 £ 30000 8 20000 m 10000 0 ^ ------— — ■------01/06/87 31/05/88 31/05/89 31/05/90 01/06/91 31/05/92 Date 142 FIG 58 SAMPLE POINT CODE - BINE04 COLNE ESTUARY OFF BATEMANS TOWER Ammonia (Pro 1985) Date COLNE ESTUARY OFF BATEMANS TOWER BOD (Pre 1985) 30 Date 143 FIG 59 SAMPLE POINT CODE - BINE04 COLNE ESTUARY OFF BATEMANS TOWER Ammonia % B ra c o E Date COLNE ESTUARY OFF BATEMANS TOWER BOD E O mo Date 144 FIG 60 SAMPLE POINT CODE - BINE04 COLNE ESTUARY OFF BATEMANS TOWER DO (Pre 1985) S 15 E 10 O 5* M h*. 00 03 o CM CO u> r- 00 0> o CM CO tO co o> o t- in in jo S> i SO a> oo co o oS g I § r«. 00 I00 § S £ § r*- oos oo ^ r»^ oo o o o o O o S p g p p o s 9 o p p p o ?> © o CO o o o CO o o O (O co CO Date 145 FIG 61 SAMPLE POINT CODE - BINE04 COLNE ESTUARY OFF BATEMANS TOWER DO Date COLNE ESTUARY OFF BATEMANS TOWER E. coli 10000 5000 o W 01/01/87 01/01/88 31/12/88 31/12/89 01/01/91 01/01/92 Date 146 FIG 62 LOWER COLNE SHELLFISH SAMPLES WRECK MARKER OFF E. MERSEA MUSSEL FLESH SAMPLES Date BRIGHTLINGSEA HARBOUR ENTRANCE MUSSEL FLESH SAMPLES Date RIVER COLNE BOUY MUSSEL FLESH SAMPLES Date COLNE POINT MUSSEL FLESH SAMPLES Date i 147 i 8 BLACKWATER ESTUARY 8.1 Historical Events from Essex River Authority Annual Report 1953-1974 1953 New sewage treatment works completed at Goldhanger. 1955 New sewage treatment works completed at Purleigh. 1958 Pollution was apparent in the vicinity of Maldon and Brookend/Witham STW. 1960 Bradwell Power Station was built. 1963 Maldon STW (old site) caused gross pollution but plans for Maldon to be diverted to Decoy Point were approved. 1964 Improvement noted at Brookend STW and Witham STW. 1966 Lagooning of effluent from Witham resulted in a good quality effluent. 1967 Decoy Point STW was completed and an improvement noted. 1974 Main part of estuary was considered clean, above Maldon the water quality was unsatisfactory. 8.2 Interpretation of Chemical Trends Fullbridge is at the head of the estuary within Maldon town. On 149 a falling tide the sample point is heavily influenced by effluent from the combined effluents from Chelmsford and Witham. There are only very limited estuary uses at this point and consequently the current quality is considered quite satisfactory. Ammonia levels show a deterioration in quality from 1988 - 1990 but more recently there has been a trend of improved, lower ammonia values (Fig 63 - 66). Herons Point shows a stable trend of satisfactory water quality results over the past few years. The combined effluents of Witham and Chelmsford pass through this point with little dilution but do not appear to have a deleterious effect. The flow from the freshwater Blackwater and Chelmer dilute any significant effects that could be caused by the combined effluents. Maintaining this quality in future is important as there are shellfisheries situated in close proximity (Fig 67 - 70) . Stansgate Abbey shows an excellent water quality partly due to the fact that "this sample point is within a large body of water capable of diluting any effluent effects. The E . coli values are very low, they are mirrored in the flesh results from the Shellfisheries resulting in a class 'A' shellfishery (Fig 71 - 74). Mersea quarters is marginally affected by Bradwell Power Stations cooling water discharge and the West Mersea STW. Despite this, water quality is excellent with respect to all parameters (Fig 75 & 76). Shellfish (Fig 77 - 79). (See Map 25 & 26 for location of sample points) 150 I 6 SML PIT OE BIBE33 - CODE POINT SAMPLE 63FIG Ammonia mg/l O IO ^ O) CO 01/07/70 01/07/71 30/06/72 . 30/06/73 01/07/74 U I > 0 n 0 3 H* c 2 01/07/75 PI H > H ►3 n n *0 » 90 »1 M ft P n Q cn 30/06/76 m n H VO C 00 > U l 50 * 30/06/77 01/07/78 01/07/79 30/06/80 FIG 64 SAMPLE POINT CODE - BIBE33 BLACKWATER ESTUARY FULLBRIDGE Ammonia 5- 8 S 7 E 6 .5c 4§ 2 3 00 s 0 CM s s 1 $ CO Date 152 FIG 05 SAMPLE POINT CODE - BIBE33 FIG 66 SAMPLE POINT CODE - BIBE33 BLACKWATER ESTUARY FULLBRIDGE DO 20 s 15 s 10 o o 5 I------lO BLACKWATER ESTUARY FULLBRIDGE E. Coli _ 100000 o ui 154 FIG 67 SAMPLE POINT CODE - BIBE28 BLACKWATER ESTUARY HERONS POINT Ammonia (pre 1985) E 4 .2 3 i? ...... A^...H ... o i-rgco ■*}■ m co r-> oo 05 o 00 ooooooSooooSh-r-totDi^h-cptph-r'-cDtf* 00<0c000c0(000c0<0r- O O t- •*— O O ■*— t— O O Date BLACKWATER ESTUARY HERONS POINT BOD (Pre 1985) % £ a mo Date 155 FIG 88 SAMPLE POINT CODE - BIBE28 09 n R M co M 3 3 o is* w g o S o n o . 6 to to * * i “ 3 31/03/88 01/04/85 01/04/90 01/04/87 31/03/92 01/04/91 01/04/89 01/04/86 Date FIG 69 SAMPLE POINT CODE - BIBE28 BLACKWATER ESTUARY HERONS POINT DO (Pre 1985) Date BLACKWATER ESTUARY HERONS POINT E. coli (Pre 1985) 30000 25000 20000 15000 o 10000 ui5000 0 : 0 CNJ CO to 00 O) o £ S° 00 S Si toI to to VO 1 i s s s o o i s s p T" i T" CO w CO CO CO Date 157 FIG 70 SAMPLE POINT CODE - BIBE28 BLACKWATER ESTUARY HERONS POINT DO 161 i l l 8 I n2 01/04/85* 31/03/88 01/04/90 31/03/92 01/04/86 01/04/87 01/04/91 01/04/91 O & 01/04/89 BLACKWATER ESTUARY HERONS POINT E. coli _ 3000( | 25001 3I T © 20001 ^ 15001 o 10001 ui 500( S 00 CO O CM 00 CO 00 CO 0) 0) i- ^ ^ ^ O O ^ r* O O r- r- ▼- t— T— O O CO CO o o Date 158 FIG 71 SAMPLE POINT CODE - BIBE19 BLACKWATER ESTUARY OFF MARCONI S/C STANSGATE Ammonia (Pre 1985) Date BLACKWATER ESTUARY OFF MARCONI S/C STANSGATE BOD (Pre 1985) Date 159 FIG 72 SAMPLE POINT CODE - BIBE19 BLACKWATER ESTUARY OFF MARCONI S/C STANSGATE Ammonia 0.5 5 0.4 E .2 0.3 c | 0.2 | 0.1 ...... 01/07/90 01/07/91 30/06/92 Date BLACKWATER ESTUARY OFF MARCONI S/C STANSGATE BOD % E a o m 01/05/90 01/05/91 30/04/92 Date 160 FIG 73 SAMPLE POINT CODE - BIBE19 BLACKWATER ESTUARY OFF MARCONI S/C STANSGATE DO (Pre 1985) Date BLACKHATER ESTUARY OFF MARCONI S/C STANSGATE E. coll (Pre 1985) Date 161 FIG 74 SAMPLE POINT CODE - BIBE19 BLACKWATER ESTUARY OFF MARCONI S/C STANSGATE DO Date BLACKWATER ESTUARY OFF MARCONI S/C STANSGATE E. coli 1200 _ 1000 o1 800 5 600 8 400 ui 200 01/05/90 01/05/91 30/04/92 Date 162 I 7 SML PIT OE BIBE08 - CODE POINT SAMPLE 75FIG BOD mg/l Ammonia mg/l O -»■ PO w ^ o» o o k)o ob> a o bio a 09 is 9B 2o tn g ®l! 00-PS 5 I s3 § f s § | S 5 w »| 5 | c ■I » £ FIG 78 SAMPLE POINT CODE - BIBE08 BLACKWATER ESTUARY MERSEA QUARTERS DO Date 164 FIG 77 BLACKWATER SHELLFISH SAMPLES GOLDHANGER CREEK PACIFIC OTSTER FLESH SAMPLES oO) e uo ui oO) Date BENCH HEAD ST. PETERS FLATS OTSTER FLESH SAMPLES OYSTER FLESH SAMPLES oO) o o ®« ui C oO) Date Date THE NASS BATCHELOR SPIT OYSTER FLESH SAMPLES OYSTER FLESH SAMPLES Date Date THIRSLET CREEK BUXEY SANDS MUSSEL FLESH SAMPLES COCKLE FLESH SAMPLES iii oo> 01/01/92 28/10/92 Date Date 165 FIG 78 WEST MERSEA SHELLFISH SAMPLES THE NOTHE OYSTER FLESH SAMPLES Date TOLLESBURY SOUTH OYSTER FLESH SAMPLES 5 £ 10000 § $ 1000 [Class B ui= 100 > Class A o oo 10 1 01/10/91 30/09/92 Date LITTLE DITCH OYSTER FLESH SAMPLES o> 10000 UJ g £ 3 100 ^Class A o 1 01/10/91 30/09/92 Date SALCOTT OYSTER FLESH SAMPLES Class A 01/10/91 30/09/92 Date TOLLESBURY NORTH OYSTER FLESH SAMPLES § -c 10000 Oo 0) 1000 • w ® 100 .Class A o0)0 o 10 -I 1 01/10/91 30/09/92 Date 166 FIG 79 EAST MERSEA SHELLFISH SAMPLES PYEFLEET SPIT OYSTER FLESH SAMPLES Date PEEWIT ISLAND OYSTER SAMPLES Date 167 \Vt ....\ y ’ ;; oJciL O l T •- \ t *V1,M ^♦ISwivUMlpOg » *:j ‘ i, ' i 'i f t 6 J > c ^ 'v - ______v°! ft-JTv -xx. 0 00 clcft I , > D \ ■ ;c£' £8 C8 w ll*H . a'•■’ill ii'totN PMDC ,?* iwtw^4M0o ^ I Jj r ‘ *r> iJ *V « ? : ■ ••• ,.V-i *ti ft lirn«w| • .<' * :P \V \«A 5 - *r T --s‘w - •■-V ! kO,V '*''5-0. •*< $ ik^gppi V put’lACw liru V*/ ^ -"" - , j \ -t ;\ ftU 1 ' JlCu3Q :' f| ...r » . X. V •*** >6*«i " I IV" >»T ! / < '*>1 /■ '1C 1 ^ I H. / ^oeaaii _»-'^',| "Vj Y ' >V 5 ‘ ' ■"''£ J- -•, % o Aluti'+t} |s| >\f ■ ~ >t»oviu«.r^’^|VH pr* *%o fj | V"v‘ t... - l i • •”'i" '>**0 V - W '• O PI..WK.,, 1 Y O O l .. ' % ' V .$'C'l\ ,-f - . purni A^sujey 613010 j)^ x >, t. k'i; ia/^/lS/O A/ |l*v>png irg apv»*j**ri : / \o " -90-- *ih>h •mTJm fJ'W— pu»l*j^»0*0 f suaia, 7*#j*3 pmm ...ki ■,,Tl I ci]flia -IQ yS T" J O ^ l,rLV ezagia *'3 " "Pf'Qr1 lUo^ im( tt«J L r^l!39l0 -i v6nQ ■ > v » j OHC.Ai\*t v■\n» OL «*») «e*tn 2 U 10 00 | fi 16 •» f (!) liwuo' .. f* \*+\i on^k«nOl }J /• ,H*S ' •* / tA|.r«ol \. ' "V -iftfTiwi lunut»t|o^ Muo^sauoj^AO/V.0 •, ^ -i SINIOd 31dl/\IVS . p.UiMJ -■» i —iO A- .// A^vnisa yaivMviovna r m \. Abbot's Wick F.W N ew Halt ^ " C h estnuts' 2 B Row se’s 6 Fm o Fm 8owei > 1E 1 Ray HaM/ BIBEO720 ’stand "0 Abbotts,. __ _ _ if ro *21 BIBE0640 W.' i jQwrtthouse V^W eat^rcocr j" ? T^bbdtsW all Saltings Feldy larshes fP Bridge JV IR B Sta F/r/ L — \ Olc^Ha Inn n • Old Hall Fm 0^^(PennyQple (Cobmarsh^^YV; EST, MERSEA > Fleet'jfiy ^|sUprt ; / X IIBE0250 Court 6 v? ' Tollesbury Ftelt . . /V< \ch r^iP^ii{IBE062lf/ IBE0610 - . The IS jatCob Island iy!MilBE0^70 ;hinglehead q Jq oh 02 03 White HouseT I Fm \ Fm PrenticeJe .fi^tl.Hall— li~ Fm - q*1- ' <^t f & BIBE076^ + yck.e^rn ./ o \ : Jetty? Sate: I1 09 / < v a “r - lO D e r.n y Fn» iWcymdr)<.5y Fm y r >1 fi jRolls Fm \ J - 'V^U. i o ) 9 CROUCH ESTUARY 9.1 Historical Events from Essex River Authority Annual Report 1953-1974 1958 - . The estuary showed signs of pollution in the upper reaches. 1959 - Extensions to the Western STW were completed. 1963 - Gross localised pollution occurred around Burnham STW. 1964 - Unsatisfactory effluent was noted at Western STW. 1968 - Activated sludge treatment plant at Burnham resulted in some effluent improvement. 1972 - Head of the estuary was heavily polluted by Shotgate and Western STW's. 1974 - Water quality has much improved. 9.2 Interpretation of Chemical Trends Battlesbridge shows effects from the STW at Wickford and others in this locality. Ammonia levels regularly exceed the 1.5 mg/l requirement. The BOD shows similar trends with values in excess of 4 mg/l frequently. The elevated levels of E. coli are of some concern as there is a shellfishery immediately downstream (Fig 80 - 83) . Hullbridge shows a similar pattern to Battlesbridge with a slight 170 improvement. The quality is not satisfactory when you take into consideration the extensive usage of the estuary (Fig 84 - 87). Ammonia levels at North Fambridge show a definite improvement on those found at Battlesbridge and Hullbridge upstream. Similarly the BOD and DO levels show that the water is of a satisfactory quality (Fig 88 - 90). Essex Yacht Marina shows similar results to North Fambridge. However, the sewage treatment works at Burnham-on-Crouch does have some influence on the water quality in this area. BOD's are marginally higher than North Fambridge and appears to be influenced partly by eutrophication effects. E. coli levels are low and considered satisfactory (Fig 91 - 93). Shellfish analysis results are to infrequent to show a true picture of quality. There appears to be widespread variation at all three sampling areas encompassing all three classes, A, B and C. The samples in the mid estuary are most probably affected by the poor quality of the upper estuary whereas the lower Crouch shellfisheries are affected by the Burnham-on-Crouch STW (Fig 94) . (See Map 27 for location of sample points) 171 FIG 80 SAMPLE POINT CODE - BICE17 CROUCH ESTUARY BATTLESBRIDGE Ammonia (Pre 1985) % I CO CO CO o o o (O CO CO Date CROUCH ESTUARY BATTLESBRIDGE BOD (Pre 1985) CO CO CO o o CO CO CO Date 172 FIG 81 SAMPLE POINT CODE - BICE17 CROUCH ESTUARY BATTLESBRIDGE Ammonia CO CO 173 FIG 82 SAMPLE POINT CODE - BICE17 CROUCH ESTUARY BATTLESBRIDGE DO (Pre 1985) CO CO CO o o CO CO CO Date CROUCH ESTUARY BATTLESBRIDGE E. coli (Prel985) 300000 I 250000 © 200000 £ 150000 g 100000 50000 UJ h- 00 o> p (0 00 co ioo 00 § oo oo I p p P p p p 174 FIG 83 SAMPLE POINT CODE - BICE17 CROUCH ESTUART BATTLESBRIDGE E. coli 300000 oE 250000 ▼»o 200000 rs 150000 o 100000 50000 ui 0 175 FIG 84 SAMPLE POINT CODE - BICE14 CROUCH ESTUARY HULLBRIDGE Ammonia (Pre 1985) Date CROUCH ESTUARY HULLBRIDGE BOD (Pre 1985) CO 176 FIG 85 SAMPLE POINT CODE - BICE14 CROUCH ESTUARY HULLBRIDGE Ammonia 3.5 2.! 4 1.1 4 O.J ir> co 00CO ooa> 177 FIG 86 SAMPLE POINT CODE - BICE14 CROUCH ESTUARY HULLBRIDGE DO (Pre 1985) % E O o co co CO o o o CO CO CO Date CROUCH ESTUARY HULLBRIDGE E. coli (Pre 1985) 60000 E 50000 e 40000 30000 fjo 20000 ui 10000 0 co 00 o p £ oo £ u> £ in to 25 o Q p o p p p Date 178 FIG 87 SAMPLE POINT CODE - BICE14 CROUCH ESTUARY HULLBRIDGE DO 25 SI' 15 O 10 > ------t ------* ------incpr~ooo>Of-c\i 00 00 CO 00 CO Q) O) O) s s s s s s s s CO O O O CO Date CROUCH ESTUARY HULLBRIDGE E. coli 80000 c 70000 o 60000 ® 50000 £ 40000 o 30000 ° 20000 uj 1 0 0 0 0 0 179 T] o DO mg/l Ammonia mg/l 00 01/11/57 01/11/57 r 01/11/58 01/11/58 01/11/59 01/11/59 31/10/60 31/10/60 01/11/61 01/11/61 01/11/62 01/11/62 01/11/63 01/11/63 31/10/64 31/10/64 01/11/65 a § Q 01/11/65 01/11/66 01/11/66" 01/11/67 ^ 3 Q 01/11/67H 31/10/68 *0 u o (t' 1 W• * 31/10/68" o> 01/11/69 ® 5 M S 01/11/69" 01/11/70 H 0 “ * 01/11/70 01/11/71 « » 3 01/11/71 M® w u *4 M 31/10/72 ui q 2 31/10/72 01/11/73 n K 01/11/73 01/11/74 01/11/74 01/11/75 01/11/75 31/10/76 31/10/76 1 01/11/77 01/11/77 01/11/78 01/11/78 CO 01/11/79 01/11/79 > 31/10/80 31/10/80 ■0s 01/11/81 01/11/81 mr~ "0 E. coli/ 100ml BOD mg/l o 0 o o o o o o o o io a o o o o o o o 01/11/57 m o o o o o o o o 1 01/05/66 01/11/58 gj 01/11/59 o 01/05/67 31/10/60 m o 30/04/68 01/11/61 CO 01/11/62 30/04/69 01/11/63 01/05/70 31/10/64 01/11/65 01/05/71 01/ 11/66 30/04/72 01/11/67 30/04/73 31/10/68 01/11/69 01/05/74 01/11/70 01/05/75 01/11/71 31/10/72 30/04/76 01/11/73 30/04/77 01/11/74 01/11/75 01/05/78 31/10/76 01/05/79 01/11/77 01/11/78 30/04/80 01/11/79 30/04/81 31/10/80 01/11/81 FIG 89 SAMPLE POINT CODE - BICE09 CROUCH ESTUARY NORTH FAMBRIDGE Ammonia I .J U * A - ii'il*-" in CD CO O O CM GO €0 00 CO 00 O) 0> O) | | | S | S S S © o o c o o o o e o Date CROUCH ESTUARY NORTH FAMBRIDGE BOD % E Q mo Date 181 FIG 90 SAMPLE POINT CODE - BICE09 CROUCH ESTUARY NORTH FAMBRIDGE DO 14 12 10 * I § 4 00 oo oo co co a> a> a> 1 i i § i § i s T- T- ■*— T— T“ T— ■<— O O O CO O O O CO Date CROUCH ESTUARY NORTH FAMBRIDGE E. coli _ 7000 E 6000 g 5000 4000 S 3000 S 2000 uj 1000 00I"- 00 CM a § o o o o CO CO 182 FIG 91 SAMPLE POINT CODE - BICE05 CROUCH ESTUARY CROUCH ESTUARY ESSEX YACHT MARINA ESSEX YACHT MARINA Ammonia (Pre 1985) BOD (Pre 1985) E o o 00 co CO CO CO CO CO. Date Date CROUCH ESTUARY CROUCH ESTUARY ESSEX YACHT MARINA ESSEX YACHT MARINA DO (Pre 1985) E. coli (Pre 1985) 12 10 % 8 E 6 O O 4 2 0 o> o00 oo OOCM i CO CO CO T- y-5 CO co CO CO CO Date Date 183 FIG 92 SAMPLE POINT CODE - BICE05 CROUCH ESTUARY ESSEX YACHT MARINA Ammonia o o o o k j i Ammonia mg/l Ammonia ■ 3k)4k.a>a>-*ro^ la WMUM u u J * t 31/03/92 01/04/90 01/04/90 01/04/91 31/03/88 U I / U H / 0 3 01/04/87 C 01/04/86 a 01/04/89 sr CROUCH ESTUARY ESSEX YACHT MARINA BOD ill. ill 8?" 31/03/92 01/04/90 01/04/90 01/04/91 31/03/88 01/04/85* 01/04/86 01/04/87 5? 01/04/89 5? O 184 FIG 93 SAMPLE POINT CODE - BICE05 CROUCH ESTUARY ESSEX YACHT KARINA DO 10 if IS" 2 4 2 31/03/92 01/04/91 01/04/91 31/03/88 01/04/90 01/04/85* 01/04/86 01/04/87 5? 5? 01/04/89 O CROUCH ESTUARY ESSEX YACHT MARINA E. coli _ 2500 | 2000 ® 1500 | 1000 “ 500 m C r- qo o) o ^ cm CO co co oj a) o> ^ CO CT 185 FIG 94 CROUCH SHELLFISH SAMPLES ALTHORNE CREEK OYSTER FLESH SAMPLES Date OUTER CROUCH OYSTER FLESH SAMPLES Date 186 ' ^ s,uRjitfFEi L/ r r 'i I V , J I J 03^V“ -. ,. '“b I • i n- . .. -r-." ■•••<-. j "M p t e ^ ~ : S i k i q.«j loi*} O' <0' ( BICE06 SCM.! 1 50 000 •» OWM< 10 ROACH ESTUARY 10.1 Historical Events from Essex River Authority Annual Report 1953— 1974 1967 - Evidence of estuarine pollution was noted at Rochford due to the sewage discharges. 1972 - The estuary was frequently polluted by discharges of settled sewage from the overloaded Rochford STW and Great Stambridge STW. Oysters were affected. 1974 - Some improvements resulted from the extensions at Eastern STW. 10.2 Interpretation of Chemical Trends It is apparent the ammonia levels have improved since the late 1980's at Ropers Farm, Barling and levels are now considered to be satisfactory. Eutrophication effects appear to be partly influencing the BOD. Both E . coli and DO values are considered to be satisfactory. However, occasional erratic values of E. coli may influence the nearby shellfishery (Fig 95 - 97). At East End Paglesham the trend of improving ammonia is noted and BOD values again show the effects of eutrophication. The E. coli values tend to be quite erratic and this may be due to storm overflows (Fig 99 & 100). At Monkton Quay the ammonia levels are lower than those found at East End Pagelsham, similarly BOD, DO and E. coli show a water quality of a good standard (Fig 101 - 103). The levels are 188 satisfactory for the nearby shellfishery which supports both oysters and mussels at class A/B (Fig 104). (See Map 28 for location of sample points) 189 FIG 95 SAMPLE POINT CODE - BIRE16 ROACH ESTUARY ROACH ESTUARY OFF ROPERS FARM BARLING OFF ROPERS FARM BARLING Ammonia (Pre 1985) BOD (Pre 1985) ’s'.Y'wy o 00 05 00o Q8 Q£ o£ o£ o£ £o o QS OT* ^O Date ROACH ESTUARY ROACH ESTUARY OFF ROPERS FARM BARLING OFF ROPERS FARM BARLING DO (Pre 1985) E. coli (Prel985) 14 _ 12000 12 \ ■ - E 10000 ■ 11 c 10 o 8000 I 8 h i O 8 Z 6000 o 4 g 4000 2 uj 2000 0 O' CO to CD 00 03 o 00 00 £ £ h- £ 15 h* o Ip p o O o P p p P O o o Date Date 190 FIG 96 SAMPLE POINT CODE - BIRE16 ROACH ESTUARY OFF ROPERS FARM BARLING Ammonia so c 0. 0 0. 1 °- I o «o ROACH ESTUARY OFF ROPERS FARM BARLING BOD 00ir> 191 FIG 97 SAMPLE POINT CODE - BIRE10 ROACH ESTUARY OFF ROPERS FARM BARLING DO 0000t f ) < 0 0000000)0)0) CO C> O T- CM s i s s i s i s 000?>000?) Date ROACH ESTUARY OFF ROPERS FARM BARLING E. coli 10000 E o o uo LU 192 FIG 98 SAMPLE POINT CODE - BIRE08 ROACH ESTUARY ROACH ESTUARY EAST END PAGLESHAM EAST END PAGLESHAM Ammonia (Pre 1985) BOD (Pre 1985) 11 • .A 8SCOO)OrM(<)Ttin(DSCOO) SDgDj6fc;E;SStit:t:fc:C;t:25S2 §SSo88oo8ooSSS SSoSSooSSooSSoo OOCOCOOOCOCOOOCOCOOO CO CO oococoooeocooococooococo Date Date ROACH ESTUARY ROACH ESTUARY EAST END PAGLESHAM EASTR END PAGLESHAM DO (Pre 1985) E. coli (Pre 1985) 10000 g SBjaOrNCO^lOIDNOOOOr coso 193 FIG 99 SAMPLE POINT CODE - BIRE08 ROACH ESTUARY EAST END PAGLESHAM Ammonia 8.9 1 “ — II lO 00 O) o CM 00 00 so 05 a> O) s s s %CO s s s ?5 CO o CO Date ROACH ESTUARY EAST END PAGLESHAM BOD § i J I* m 194 FIG 100 SAMPLE POINT CODE - BIRE08 ROACH ESTUARY EAST END PAGLESHAM DO tf>00 c p 00 00r*- COoo COo> 03o 03t- w03 1 § i s I s i I o o onooovo Date ROACH ESTUARY EAST ElfD PAGLESHAM E. coli 2000 E o o 1500 1000 o o 500 LlJ 0 n\,8,r a> r* 5 o 195 FIG 101 SAMPLE POINT CODE - BIRE03 ROACH ESTUARY ROACH DATA MONKTON QUAY FOULNESS MONKTON QUAY FOULNESS Ammonia (Pre 1985) BOD (Pre 1985) to to CO CO CO Date Date ROACH ESTUARY ROACH ESTUARY MONKTON QUAY FOULNESS MONKTON QUAY FOULNESS DO (Pre 1985) E. coli (Pre 1985) CO CO CO 31/03/82 Date Date 196 FIG 102 SAMPLE POINT CODE - BIRE03 ROACH ESTUARY MONKTON QUAY FOULNESS BOO moo oo CO 0009 § a> pCM CO§ CO I s o s s | T“ I g o CO o CO Date 197 FIG 103 SAMPLE POINT CODE - BIRE03 ROACH ESTUARY MONKTON QUAY FOULNESS DO t ’l k 8 1 1/04/87 1/04/87 01/04/91 01/04/91 31/03/92 31/03/88 01/04/90 01/04/86 01/04/86 0 01/04/85< 01/04/85< a 01/04/89 §* ROACH ESTUARY KONKTON QUAY FOULNESS E. coli _ 700 E 600 g 500 400 s 300 1 8 200 \ ui 100 o J- r-> co eo a> cm cm 00 oo co THE DUNHOPES OYSTER FLESH SAMPLES Date BLACKLEDGE MUSSEL FLESH SAMPLES o uj oa> Date MIDDLEWAY OYSTER FLESH SAMPLES o, 100000 © 1Q000 5 £ O m 1000 o. c® 100 Ul O) 10 O 1 01/01/92 31/12/92 Date PAGLESHAM POOL OYSTER FLESH SAMPLES O) QO ©m UJ oo> Date 199 KJ4 ijssbp ™ — ■>■■■■■■ A). >$>'• -.:■<*■■■■-■.■<■. -■'.■> w„u„v., aoii H.ti^*. Canewdon! ROACH ESTUARY '£?"■"■ ^ 1 ^TMSFt SAMPLE POINTS M j , : , f , M h • 'W A L l | a S E A ISLAND Lqftmjm „* ; , '< ' ' ,BBipgini Fm ^.StTmbridgel ■.»••••■. fllj • y-/Q.H»mp'tOH B»m» ‘ \U__ 4-Wis Sirton Hill W./i ,<%>!?.vH ' ■ POTTON . 91« m , I5LANQ s,,*== X ’*f 1 C n / B Miish ^ qc 1 V ^ /\ \ * > ' / >1 Xh G O 10 90 X \ 94'‘ ‘ 96 ■■ Ropcr't Fm ^ 1 \ ' 21'/ ■? /*’ ' s>^d )a \ £2==^. Ips \ v.T^'Hss^.r. ”"; - ~i:y \ ' ^ ‘.Danger-// ^Fl^VH.U tuckir JSullpn'Bfiitgtfjn - ---- /--tmWj* *' 'VVN^P.Si Ar'^a !('/ fritV r ' W " U -V ^ B 1 R b 1 7 I. . (• . I Hjh“^ T'fmBlue HOtrie Little njj Wa^'in^ ■^i'%. .< ^ I c J T s S s,r - V - 1 ' %,» t'j«T ' DANGER AREA 8 7 ...... Bourne i" 1 * 1 P Gntft i» ; pv^'3J- North '. i > Shoebury- t _ o_§L o> s s s s s s s s OO OCOOOOCO Date