Sanitary Survey - Review

Blackwater – 2021

Document No. – J0591/21/01/06

Carcinus Ltd, Wessex House, Upper Market Street, Eastleigh, Hampshire, SO50 9FD. Tel. 023 8129 0095 https://www.carcinus.co.uk/ Cover image: Aerial view of the Dengie coastline. Image © Terry Joyce CC-BY-SA 2.0

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Carcinus Ltd – Document Control Sheet

Client Food Standards Agency (FSA)

Project Title Sanitary Survey Review

Document Title Sanitary Survey Review - Blackwater

Document Number J0591/21/01/06

Revision 3.0

Date 06 April 2021

Revisions Revision No. Date Comment

1.0 19 January 2021 Draft for FSA review

2.1 03 February 2021 Draft for external consultation

3.0 06 April 2021 Final draft following external consultation

Document QA and Approval Name Role Date

Author Joshua Baker Freshwater and Marine 06 April 2021 Ecologist

Checked Matthew Crabb Director 06 April 2021

Approved Matthew Crabb Director 06 April 2021

Initial Consultation Consultee Date of consultation Date of response

Maldon Council 27 November 2020 24 December 2020

Environment Agency 27 November 2020 23 December 2020

Secondary Consultation Consultee Date of consultation Date of response

Maldon District Council 09 February 2021 12 March 2021

Local Action Group 10 February 2021 25 February 2021

A sanitary survey relevant to the bivalve mollusc beds in the Blackwater BMPA was undertaken in 2013 under EC Regulation 854/2004 (now superseded by retained EU Law Regulation (EC) 2019/627). This provided appropriate hygiene classification zoning and monitoring plan based on the best available information with detailed supporting evidence. In line with regulatory and EU guidance the Food Standards Agency undertake targeted sanitary survey reviews to ensure public

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health protection measures continue to be appropriate. This report provides a review of information and recommendations for a revised sampling plan if required. Carcinus Ltd. (Carcinus) undertook this work on behalf of the FSA. Carcinus Ltd accepts no liability for any costs, losses or liabilities arising from the reliance upon or use of the contents of this report other than by its client.

Dissemination Food Standards Agency; Maldon District Council. The report is publicly available via the Carcinus Ltd. website.

Recommended Bibliographic Citation: Carcinus Ltd., 2021. Review of the Blackwater 2013 Sanitary Survey. Carcinus report on behalf of the Food Standards Agency, to demonstrate compliance with the requirements for classification of bivalve mollusc production areas in England and Wales under retained EU Law Regulation (EC) 2019/627.

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Contents

List of figures ...... vi List of tables ...... vii 1 Introduction ...... 1 1.1 Background ...... 1 1.2 Blackwater Review ...... 1 1.3 Assumptions and limitations ...... 3 2 Shellfisheries ...... 3 2.1 Description of Shellfishery ...... 3 2.1.1 Pacific oyster ...... 4 2.1.2 Native oyster ...... 4 2.1.3 Cockle ...... 4 2.1.4 Hard clams ...... 4 2.2 Classification History ...... 5 3 Pollution sources ...... 6 3.1 Human Population ...... 6 3.2 Sewage ...... 9 3.3 Agricultural Sources ...... 13 3.4 Wildlife ...... 17 3.5 Boats and Marinas ...... 17 3.6 Other Sources of Contamination ...... 19 4 Hydrodynamics/Water Circulation ...... 19 5 Rainfall ...... 19 6 Microbial Monitoring Results ...... 20 6.1 Summary Statistics and geographical variation ...... 20 6.2 Overall temporal pattern in results ...... 24 6.3 Seasonal patterns of results ...... 26 7 Conclusion and overall assessment ...... 28 8 Recommendations ...... 30 8.1 Pacific oyster ...... 30 8.2 Native oyster ...... 31 8.3 Cockles ...... 31 8.4 Hard clams ...... 32 8.5 General Information ...... 32

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8.5.1 Location Reference ...... 32 8.5.2 Shellfishery ...... 32 8.5.3 Local Enforcement Authority(s) ...... 32 9 References ...... 36 Appendices ...... 37 Appendix I. Breakdown of population change ...... 38 Appendix II. Blackwater Sanitary Survey Report 2013 ...... 44 About Carcinus Ltd ...... 45 Contact Us ...... 45 Environmental Consultancy ...... 45 Ecological and Geophysical Surveys...... 45 Our Vision ...... 45

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List of figures Figure 1.1. Location of the Blackwater estuary and surrounding areas...... 2 Figure 2.1 Current Classification Zones and associated Representative Monitoring Points (RMPs) for the different species harvested in the Blackwater BMPA...... 5 Figure 3.1 Human population density in 2001 and 2011 census Super Output Areas (lower layer) that intersect the Blackwater catchment...... 7 Figure 3.2 Population change between the 2001 and 2011 censuses for Wards and Electoral divisions (based on 2011 boundaries) that are within or partially within the Blackwater hydrological catchment (wards have been clipped to the boundary of the hydrological catchment). 2001 Census data have been transposed to 2011 wards using the UK Data Service’s GeoConvert tool (UK Data Service, 2020) to facilitate comparison. Numbers within wards are identifiers that can be used in combination with Appendix I to provide more detail...... 8 Figure 3.3 Locations of all consented discharges in the vicinity of the Blackwater BMPA. Labels refer to continuous discharges, details of which can be found in Table 3.1...... 9 Figure 3.4 Livestock population change between 2013 and 2016 for Local Authority Districts and areas of pasture within the Blackwater catchment...... 15 Figure 3.5 Locations of moorings, marinas and other boating activities near the Blackwater BMPA. 18 Figure 5.1 Mean daily rainfall (mm) per month for the Blackwater at Langford (TL835090) for the period (A) 2010 – 2013 (pre sanitary survey) and (B) 2014 – 2017 (post sanitary survey)...... 20 Figure 6.1 Geometric mean E. coli results from Official Control monitoring at bivalve RMPs within the Blackwater BMPA...... 22 Figure 6.2 Boxplots of E. coli levels at Pacific oyster RMPs sampled within the Blackwater BMPA 2013-Present. Central line indicates median value, box indicates lower – upper quartile range and whisker indicates minimum/maximum value excluding outliers (points >1.5 x interquartile range). . 23 Figure 6.3 Boxplots of E. coli levels at native oyster RMPs sampled within the Blackwater BMPA 2003-Present. Central line indicates median value, box indicates lower – upper quartile range and whisker indicates minimum/maximum value excluding outliers (points >1.5 x interquartile range). . 23 Figure 6.4 Boxplots of E. coli levels at cockle RMPs sampled within the Blackwater BMPA 2013- Present. Central line indicates median value, box indicates lower – upper quartile range and whisker indicates minimum/maximum value excluding outliers (points >1.5 x interquartile range)...... 24 Figure 6.5 Timeseries of E. coli levels at Pacific oyster RMPs sampled within the Blackwater BMPA 2013 – Present. Scatter plots are overlaid with loess model fitted to data...... 25 Figure 6.6 Timeseries of E. coli levels at native oyster RMPs sampled within the Blackwater BMPA 2003 – Present. Scatter plots are overlaid with loess model fitted to data...... 25 Figure 6.7 Timeseries of E. coli levels at cockle RMPs sampled within the Blackwater BMPA 2013 – Present. Scatter plots are overlaid with loess model fitted to data...... 26 Figure 6.8 Boxplots of E. coli levels per season at Pacific oyster RMPs sampled within the Blackwater BMPA 2013 - present...... 27 Figure 6.9 Boxplots of E. coli levels per season at native oyster RMPs sampled within the North Kent Coast BMPA 2013 - present...... 27 Figure 6.10 Boxplots of E. coli levels per season at cockle RMPs sampled within the Blackwater BMPA 2013 - present...... 28

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List of tables Table 3.1 Details of all continuous discharges in the Blackwater BMPA catchment. Those discharges not listed in the original sanitary survey are highlighted in yellow...... 10 Table 3.2 Livestock data for the Blackwater catchment between 2013 and 2016...... 16 Table 5.1 Summary statistics for rainfall before and after the sanitary survey...... 20 Table 6.1 Summary statistics of E. coli (MPN/100 g) from RMPs sampled from 2003 onwards (data cut off at December 2020)...... 21 Table 8.1 Proposed sampling plan for the Blackwater BMPA. Suggested changes are given in red underlined type...... 34

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1 Introduction 1.1 Background In line with the EU Good Practice Guide (European Commission, 2017) and Article 58 of retained EU Law Regulation (EC) 2019/627, Carcinus is contracted to undertake reviews of sanitary surveys on behalf of the Food Standards Agency (FSA). The FSA undertake targeted sanitary survey reviews to ensure public health protection measures continue to be appropriate. The report considers changes to bacterial contamination sources (primarily from faecal origin) and the associated loads of the faecal indicator organism Escherichia coli (E. coli) that may have taken place since the original sanitary survey was undertaken. It does not assess chemical contamination, or the risks associated with biotoxins. The assessment also determines the necessity and extent of a shoreline survey based on complexity and risk. The desktop assessment is completed through analysis and interpretation of publicly available information, in addition to consultation with stakeholders. 1.2 Blackwater Review This report reviews information and makes recommendations for a revised sampling plan for existing hard clam (Mercenaria mercenaria), cockle (Cerastoderma edule), native (Ostrea edulis) and Pacific oyster (Crassostrea gigas) classification zones in the Blackwater Bivalve Mollusc Production Area (BMPA) (Figure 1.1). This review explores any changes to the main microbiological contamination sources that have taken place since the original sanitary survey was conducted. Data for this review was gathered through a desk-based study and consultation with stakeholders.

An initial consultation with Local Authorities (LAs) and the Environment Agency (EA) responsible for the production area was undertaken in November 2020 This supporting local intelligence is valuable to assist with the review and was incorporated in the assessment process.

Following production of a draft report, a wider external second round of consultation with LAs and Local Action Group (LAG) members was undertaken in February and March 2021. It is recognised that dissemination and inclusion of a wider stakeholder group, including local industry, is essential to sense-check findings and strengthen available evidence. The draft report is reviewed taking into account the feedback received.

The review updates the assessment originally conducted in 2013 and sampling plan as necessary and the report should read in conjunction with the previous survey. Specifically, this review considers: (a) Changes to the shellfishery (if any); (b) Changes in microbiological monitoring results; (c) Changes in sources of pollution impacting the production area or new evidence relating to the actual or potential impact of sources; (d) Changes in land use of the area; and (e) Change in environmental conditions;

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Figure 1.1. Location of the Blackwater estuary and surrounding areas.

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Sections 2 - 6 detail the changes that have occurred to the shellfishery, environmental conditions and pollution sources within the catchment since the publication of the original sanitary survey. A summary of the changes is presented in section 7 and recommendations for an updated sampling plan are described in section 8. 1.3 Assumptions and limitations This desktop assessment is subject to certain limitations and has been made based on several assumptions, namely: • Accuracy of local intelligence provided by the Local Authorities and Environment Agency • The findings of this report are based on information and data sources up to and including December 2020; • Only information that may impact on the microbial contamination was considered for this review; and • Official Control monitoring data have been taken directly from the Cefas data hub1, with no additional verification of the data undertaken. Results up to and including December 2020 have been used within this study. Any subsequent samples have not been included. 2 Shellfisheries 2.1 Description of Shellfishery Harvesting of shellfish within the Blackwater BMPA is under the jurisdiction of Kent & Essex Inshore Fisheries and Conservation Authority (KEIFCA) and is subject to the Area A Byelaws (KEIFCA, 2021). These byelaws set out the rights and restrictions that apply to fishermen wanting to utilise the fishing waters and applies to the entire area considered in this review. Under the byelaw, limits on harvesting mean that no more than 13.6 m3 of mussels or cockles within a 24 hour period can be harvested. Additionally, fishermen dredging for shellfish may not operate a dredge that has an opening that exceeds 2 m when fishing for mussels, 85 cm for scallops or 4 m for oysters. The byelaws also impose minimum landing sizes; no more than 10% (by weight) of landed mussels should be able to pass through a space of 18 mm width and no native oysters that fit through a circular ring 7 cm diameter may be removed, though this restriction does not apply to Pacific oysters. Furthermore, the KEIFCA reserves the right to close a fishery where the bed “is so severely depleted as to require temporary closure in order to ensure recovery, or any bed or part of a bed contains mainly immature shellfish which in the interest of the protection and development of the fishery ought not to be disturbed for the time being, or any bed of transplanted shellfish ought not to be fished until it has become established…”. The Tollesbury and Mersea (Blackwater) Fishery Order, 20192 confers the rights to a several order fishery in the outer region of the Blackwater estuary, with the remaining areas a public fishery.

The Blackwater BMPA is located between the West Mersea and Colne BMPAs to the north, and the Crouch and Roach BMPAs to the south. The BMPA comprises the main body of the Blackwater estuary as well as the intertidal and subtidal area extending east from the Dengie peninsula. The fishery involves both wild and cultured stocks of the harvested species and is under the jurisdiction of Maldon District Council for Food Hygiene purposes.

1 Cefas shellfish bacteriological monitoring data hub. Available at: https://www.cefas.co.uk/data-and- publications/shellfish-classification-and-microbiological-monitoring/england-and-wales/. 2 Secretary of State, 2019. The Tollesbury and Mersea (Blackwater) Fishery Order, 2019. Available at: https://www.legislation.gov.uk/uksi/2019/974/made.

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2.1.1 Pacific oyster The original sanitary survey (undertaken in 2013) describes that the naturally occurring Pacific oyster fishery was concentrated around the firm-substrate intertidal areas in the Blackwater estuary. The survey recommended the creation of four CZs for this species, forming one large contiguous zone. These CZs were Osea South, Goldhanger, Central Blackwater and Outer Blackwater. All these CZs are remain active, with an additional 3 CZs, St Peter’s Flats, Ray Channel and St Peter’s & Bachelor classified since 2014 (the two former) and 2015 (the latter). The boundaries of the Ray Channel and St Peter’s & Bachelor CZs match those of the native oyster CZs recommended in the original sanitary survey. Consultation with the LA indicated that all beds are subject to current commercial activity, and all wild stocks are harvested via dredge.

No estimate of the current landings from this fishery or stock assessments were available to the authors of this review. 2.1.2 Native oyster At the time of the original sanitary survey, the native oyster fishery was concentrated in the subtidal areas of the Blackwater estuary and off the Dengie peninsula. All harvesting was of wild stocks, although the authors of the original sanitary survey describe that stock was at a very low level. In 2013, the Blackwater, Crouch, Roach and Colne Estuaries were designated as a Marine Conservation Zone (MCZ) (DEFRA, 2013) with the aim of protecting and recovering native oyster populations and oyster beds. The original sanitary survey recommended the designation of six CZs, covering the same area as the Pacific oyster CZs of the same name; Osea South, Goldhanger, Central Blackwater, Outer Blackwater, St Peter’s & Blackwater and Ray Channel. All these CZs are still active, with classification for all CZs except Ray Channel occurring in 2013, following the original sanitary survey. Ray Channel has been classified since 2015. No additional CZs have been classified since the original sanitary survey.

No estimate of the current landings from this fishery was available to the authors of this review. The most recently available stock assessment (Allison et al., 2020) was conducted between 2008 and 2012 (prior to the original sanitary survey) and was used to support the MCZ designation. 2.1.3 Cockle The cockle fishery was not active at the time of the original sanitary survey, although the authors of that report describe significant cockle stocks on the Dengie flats. The authors made recommendations for the creation of two CZs for cockles; Dengie Flats and Buxey Sands. Both areas are still active.

No estimate of the current landings from this fishery or stock assessments were available to the authors of this review. 2.1.4 Hard clams A fishery for the harvesting of American hard clams (M. mercenaria) was not active at the time of the original sanitary survey, or during the period of initial data collection for this review. However, information provided by the Food Standards Agency indicated that as of February 2021, three CZs within the Blackwater BMPA (Goldhanger, Central Blackwater and Outer Blackwater) were classified for hard clams. These CZs are not presented in Figure 2.1, but it is expected that the boundaries will be the same.

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2.2 Classification History The sampling plan given in the original sanitary survey proposed the creation of 18 CZs; 6 for native oysters, 7 for Pacific oysters, 3 for hard clams and 2 for cockles. The number of CZs currently classified in the BMPA has increased to 15, with an additional 3 Pacific oyster CZs. The native oyster CZs in the Blackwater estuary are currently classified using Pacific oyster samples, whereas the Pacific oyster CZs on the Dengie Flats are classified using native oyster samples. The location of all active CZs in the Blackwater BMPA are shown in Figure 2.1. Most of the CZs hold Class LT-B classifications, with only Outer Blackwater and St Peters Flats holding Class A classifications.

Figure 2.1 Current Classification Zones and associated Representative Monitoring Points (RMPs) for the different species harvested in the Blackwater BMPA.

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3 Pollution sources 3.1 Human Population The original sanitary survey cites population data from the 2001 Census of the United Kingdom. Since the publication of that document, the data from subsequent full UK census of 2011 has been made available, and so this data has been compared to that of the 2001 census to give an indication of changes in the human population within the catchment. These censuses have been used as no further population data are freely available. Changes in human population densities in census Super Output Areas (lower layer) and total population within wards within or partially within the Blackwater catchment between the 2001 and 2011 censuses are shown in Figure 3.1 and Figure 3.2 respectively.

In general, population density has increased across the entire catchment, with only 13% of wards showing a fall in population size. Average population density remains low, at only 18.84 people per hectare and much of the area has population densities of less than 4 people per hectare. The main population centres are located around Chelmsford, Braintree and Maldon, as well as at the far south of the catchment, around Southend-on-Sea. A detailed breakdown of population change for individual wards is presented in Appendix I.

At the 2001 census, the total resident population within wards wholly or partially contained within the Blackwater catchment was 905,002 people. By the 2011 census, this had increased to 971,261 people, an increase of 7.32%. The population data for the 2011 census was collected two years before the original sanitary survey was published and so could be considered more relevant to that document. The next full census of the United Kingdom is scheduled to take place in the 2021 and the UK government estimates that the national population will increase by approximately 6.6% between 2011 and 2021 (Office for National Statistics, 2018). An increase of this proportion would see the approximate population residing within the Blackwater catchment increase to 1,035,364. The potential for urban runoff remains highest from the town of Maldon at the head of the Blackwater estuary. Impacts from sewage will depend on the specific locations and nature of the discharges, changes to which are discussed in Section 3.2. Consultation with the LA did not indicate that any additional significant housing developments were planned to take place. Although without upgrades to the wastewater treatment network, an increase in population would almost certainly lead to an increase in the loading to the wastewater treatment network and would therefore potentially cause increased bacterial loading to coastal waters.

The original sanitary survey describes that the area sees a significant increase in its population during summer months due to its popularity as a tourist destination. A study published in 2017 estimated that tourist numbers had increased 3.9% since 2014 (Creed, 2017). It is expected that tourist numbers will have remained similar or increased slightly. The peak tourism season is during the summer months, and so it is expected that the loading to the wastewater treatment network will also peak during this time.

Whilst there is no recently available population data for the catchment, it is likely that the population will have increased by a small proportion since the last sanitary survey. However, the distribution of main population centres within the catchment has not changed, and as such the recommendations for RMP location are still valid.

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Figure 3.1 Human population density in 2001 and 2011 census Super Output Areas (lower layer) that intersect the Blackwater catchment.

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Figure 3.2 Population change between the 2001 and 2011 censuses for Wards and Electoral divisions (based on 2011 boundaries) that are within or partially within the Blackwater hydrological catchment (wards have been clipped to the boundary of the hydrological catchment). 2001 Census data have been transposed to 2011 wards using the UK Data Service’s GeoConvert tool (UK Data Service, 2020) to facilitate comparison. Numbers within wards are identifiers that can be used in combination with Appendix I to provide more detail.

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3.2 Sewage Details of all consented discharges in the vicinity of the Blackwater BMPA were taken from the most recent update to the EA’s national permit database at the time of sampling (November 2020). The locations of these discharges are shown in Figure 3.3.

Figure 3.3 Locations of all consented discharges in the vicinity of the Blackwater BMPA. Labels refer to continuous discharges, details of which can be found in Table 3.1.

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Table 3.1 Details of all continuous discharges in the Blackwater BMPA catchment. Those discharges not listed in the original sanitary survey are highlighted in yellow.

ID Sewage Works NGR Treatment DWF (m3/day) PACKAGE 1 APILGARTH STP TQ7035198883 Unspecified TREATMENT PLANT BENFLEET WATER BIOLOGICAL 2 TQ7700086100 6970 RECYCLING CENTRE FILTRATION BILLERICAY WATER LAGOON 3 TQ6989094200 1417 RECYCLING CENTRE SETTLEMENT CHEMICAL - BOCKING WATER 4 TL7736024280 PHOSPHATE 3900 RECYCLING CENTRE STRIPPING 5 BRADWELL-ON-SEA STW TL9929007400 UNSPECIFIED 145 CHEMICAL - BRAINTREE WATER 6 TL7669021760 PHOSPHATE 6859 RECYCLING CENTRE STRIPPING 7 BROXTED STW TL5760026600 UNSPECIFIED Unspecified

CHELMSFORD WATER ACTIVATED 8 TL7419006910 52050 RECYCLING CENTRE SLUDGE

CHEMICAL - COGGESHALL WATER 9 TL8596021370 PHOSPHATE 2235 RECYCLING CENTRE STRIPPING CHEMICAL - 10 DODDINGHURST WRC TQ6062098940 PHOSPHATE 1900 STRIPPING FELSTED(LR CHELMER) BIOLOGICAL 11 TL6681020660 1630 STW FILTRATION FOULNESS(CHURCH END) 12 TR0010093300 UNSPECIFIED Unspecified STW BIOLOGICAL 13 GOOD EASTER STW TL6303012220 44.2 FILTRATION ACTIVATED 14 GREAT DUNMOW STW TL6371021320 1900 SLUDGE

GREAT EASTON(ESSEX) BIOLOGICAL 15 TL5974025000 720 STW FILTRATION

GREAT LEIGHS WATER BIOLOGICAL 16 TL72631635 767 RECYCLING CENTRE FILTRATION

TERTIARY 17 GREAT SAMPFORD STW TL6316036250 160 BIOLOGICAL ACTIVATED 18 GREAT TOTHAM STW TL8645011580 1100 SLUDGE

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ID Sewage Works NGR Treatment DWF (m3/day)

GREAT WIGBOROUGH 19 TL9690014800 UNSPECIFIED Unspecified STW

BIOLOGICAL 20 HIGH EASTER STW TL6192015130 100 FILTRATION BIOLOGICAL 21 HIGH RODING STW TL6016016620 60 FILTRATION BIOLOGICAL 22 HIGHWOOD STW TL6550004400 45 FILTRATION PACKAGE 23 HOWE GREEN - SANDON TL7480003500 Unspecified TREATMENT PLANT CHEMICAL - INGATESTONE WATER 24 TQ6642099070 PHOSPHATE 1600 RECYCLING CENTRE STRIPPING LANGFORD RECYCLING 25 TL8037008560 UV DISINFECTION 30000 PLANT LANGFORD RECYCLING TERTIARY 26 TL8408008130 40000 PLANT* BIOLOGICAL

LATCHINGDON WATER BIOLOGICAL 27 TL8799001590 736 RECYCLING CENTRE FILTRATION

TERTIARY 28 LITTLE TOTHAM STW TL8855011410 160 BIOLOGICAL MALDON WATER ACTIVATED 29 TL8914007430 6800 RECYCLING CENTRE SLUDGE MAYLAND WATER BIOLOGICAL 30 TL9199002330 1100 RECYCLING CENTRE FILTRATION PAGLESHAM(EAST END) 31 TQ9472092230 UNSPECIFIED Unspecified STW 32 PLESHEY STW TL6680014500 UNSPECIFIED Unspecified BIOLOGICAL 33 POST OFFICE ROAD STW TL8134004570 Unspecified FILTRATION PURLEIGH WATER BIOLOGICAL 34 TL8408002700 115 RECYCLING CENTRE FILTRATION

35 RAYLEIGH EAST STW TQ8321090390 UV DISINFECTION 4600

LAGOON 36 RAYLEIGH WEST STW TQ7921094740 5827 SETTLEMENT 37 RAYNE STW TL7323023500 SAND FILTRATION 650 BIOLOGICAL 38 RIVENHALL END STW TL8440016510 80 FILTRATION

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ID Sewage Works NGR Treatment DWF (m3/day)

ROCHFORD ACTIVATED 39 TQ9290091260 8630 (STAMBRIDGE) STW SLUDGE

40 ROXWELL STW TL6490008900 UNSPECIFIED Unspecified ROXWELL WATER BIOLOGICAL 41 TL6491008860 220 RECYCLING CENTRE FILTRATION BIOLOGICAL 42 SALCOTT STW TL9530013400 56 FILTRATION BIOLOGICAL 43 SHALFORD STW TL7249029360 304 FILTRATION CHEMICAL - SHENFIELD AND HUTTON 44 TQ6503095990 PHOSPHATE 12650 WRC STRIPPING

SOUTHMINSTER WATER 45 TQ9598098700 OXIDATION DITCH 900 RECYCLING CENTRE

BIOLOGICAL 46 STISTED STW TL8020024600 300 FILTRATION STONE ST LAWRENCE 47 TL9550004850 PASVEER DITCH 322 STW BIOLOGICAL 48 TILLINGHAM STW TL9873004270 200 FILTRATION TIPTREE WATER ACTIVATED 49 TL9389015720 2400 RECYCLING CENTRE SLUDGE

TOLLESBURY WATER BIOLOGICAL 50 TL9651011030 600 RECYCLING CENTRE FILTRATION

TOLLESHUNT D'ARCY BIOLOGICAL 51 TL9220010500 210 STW FILTRATION

WETHERSFIELD WATER BIOLOGICAL 52 TL7056030590 955 RECYCLING CENTRE FILTRATION

WHITE NOTLEY WATER LAGOON 53 TL7903018230 660 RECYCLING CENTRE SETTLEMENT

54 WILLOWS GREEN STW TL7182420064 UNSPECIFIED Unspecified

55 WIMBISH STW TL5918036200 UNSPECIFIED Unspecified ACTIVATED 56 WITHAM STW TL8414007800 8100 SLUDGE WOODHAM FERRERS LAGOON 57 TQ8004097170 3900 STW SETTLEMENT

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ID Sewage Works NGR Treatment DWF (m3/day)

WOODHAM WALTER BIOLOGICAL 58 TL8155007430 77 WATER RECYCLING FILTRATION

*The EA database gives no DWF for the Langford Recycling Plant (ID: 26) but a Max Daily Flow of 40,000 m3/day. This value has been plotted as the DWF for this discharge in Figure 3.3

The original sanitary survey identified a total of 46 continuous discharges within the Blackwater catchment (p46, Figure II.1; p47-48, Table II.1). Most of the identified discharges were located upstream of the shellfish beds, and so were expected to pose a limited risk to the shellfishery due to bacterial die off. The most significant sewage treatment works (STW) in terms of the contamination risk it poses was the Chelmsford STW, due to both the volume of discharge (52,050 m3/day) and the treatment (secondary). Consultation with the EA did not indicate any upgrades to continuous discharges to the Blackwater Estuary. A total of 58 continuous discharges were identified as having active consents within operational catchments draining to the BMPA. However, all these additional discharges are located a significant distance away from the shellfish beds and are therefore unlikely to pose a significant change to the level of bacterial loading within the BMPA.

In addition to the continuous discharges, the original sanitary survey identified a total of 32 intermittent discharges within 2 km of the estuary and Dengie flats. Intermittent discharges comprise Combined Storm Overflows (CSOs), storm tank overflows and pumping station emergency overflows. Only 5 of the intermittent discharges active at the time of the original sanitary survey are no longer active, and only one additional discharge, though this is located at least 3 km from the Blackwater estuary. No spill event monitoring was available to the authors of the original sanitary survey or this review. However, as patterns of rainfall have remained similar (see Section 5), the frequencies of spill events are predicted to have remained similar. As such, the impact on bacterial loading as a result spills is not expected to have changed, particularly as consultation with the LA and EA did not indicate any upgrades to the wastewater treatment network.

Finally, the original sanitary survey described the positions of four private discharges with consented max daily flows of more than 10 m3/day. Whilst there are some additional private discharges to water near to the shellfish beds, most are relatively low volumes (< 103/day). The only discharge that is above this employs UV disinfection, and so when treatments are operational the risk of increased faecal loading is relatively low.

The most at-risk areas to contamination from this source of pollution remain those CZs closest to the head of the estuary, and the areas of those CZs closest to shore are likely to receive the greatest faecal loading. However, as the anticipated extent of this loading is not predicted to have increased significantly, the recommendations made in the original sanitary survey to capture these sources of pollution remain valid. 3.3 Agricultural Sources The original sanitary survey provides livestock population data based on the 2010 agricultural census. Updated data at the same spatial scale were not freely available to the authors of this review, however livestock data for the Local Authority Districts that fall within or partially within the Blackwater catchment were available for 2013 and 2016 (DEFRA, 2018). As only a small proportion of some of the districts falls within the catchment, the livestock data have been adjusted to reflect

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the % of each district that falls within the catchment. This assumes that livestock are distributed uniformly throughout the district and, therefore, some inaccuracies may be present. Aggregate adjusted livestock population change data are shown in Figure 3.4 and Table 3.2.

Overall, livestock populations have increased by 4.2% since the original sanitary survey, although there are significant differences between different authorities; the overall population in the Colchester district increased by 66.73%, whereas the Epping Forest district saw a decrease of 44.38%. The greatest increase was in sheep populations, although the numbers for this species are skewed as some areas increased their sheep populations by more than 2,000%.

Only a relatively small proportion of the total catchment is covered by pasture (Figure 3.4), based on 2018 land cover data. The average livestock density in the catchment is relatively low relative to other areas of the country, at 5.19 animals per hectare. The principal route of contamination of coastal waters by livestock is surface run-off carrying faecal matter to coastal waters. Land cover maps indicate that only a few areas of pasture sit immediately adjacent to a water body, particularly on the north coast of the Blackwater estuary, and so whilst the overall effect of this form of contamination is likely to be relatively minor, point source impacts may occur following high rainfall events, particularly following a prolonged dry period. These pasture locations have not changed since the original sanitary survey. The livestock population within the catchment will also vary throughout the year, with highest numbers occurring during Spring and lowest numbers when animals are sent to market in Autumn and winter.

Despite the fact that livestock populations have increased since the original sanitary survey, livestock densities are still relatively low and the probable routes of contamination remain unchanged. As such, the recommendations made in the original sanitary survey to capture this source of pollution remain valid.

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Figure 3.4 Livestock population change between 2013 and 2016 for Local Authority Districts and areas of pasture within the Blackwater catchment.

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Table 3.2 Livestock data for the Blackwater catchment between 2013 and 2016.

Local Number of Livestock (Adjusted)

Authority Cattle Sheep Pigs Poultry

District

Catchment

area

Catchment

Catchment (Ha)

%area LA within Areaof within LA

%of total 2013 2016 % Diff 2013 2016 % Diff 2013 2016 % Diff 2013 2016 % Diff Southend- 4118.31 60.68% 2.45% 119 100 -16.63% 5 139 2687.84% 90 81 -9.18% 10251 9372 -8.57% on-Sea Rochford 16915.80 64.34% 10.05% 520 434 -16.63% 22 606 2687.84% 390 354 -9.18% 44643 40818 -8.57% Castle Point 2484.89 38.98% 1.48% 46 39 -16.63% 2 54 2687.84% 35 32 -9.18% 3973 3633 -8.57% Basildon 8650.40 78.32% 5.14% 814 807 -0.81% 780 0 -100.00% 24 0 - 2399 3205 33.60% 100.00% Brentwood 8053.44 52.59% 4.79% 97 40 -58.96% 203 213 5.08% 1866 1858 -0.43% 21481 19568 -8.91% Chelmsford 34224.76 99.78% 20.34% 1844 2488 34.91% 2177 1832 -15.86% 3152 4241 34.54% 223906 289257 29.19% Maldon 35418.24 82.74% 21.05% 3564 3316 -6.98% 5957 5554 -6.77% 2649 7202 171.90% 553674 737972 33.29% Braintree 27732.94 45.34% 16.48% 2467 2154 -12.70% 3368 3110 -7.66% 5224 4129 -20.96% 217812 166058 - 23.76% Colchester 5248.36 15.13% 3.12% 467 438 -6.18% 1571 1484 -5.54% 820 402 -50.95% 22959 40721 77.36% Epping 742.89 2.19% 0.44% 67 58 -12.99% 126 135 7.01% 182 152 -16.52% 4135 2163 - Forest 47.68% Uttlesford 24654.90 38.45% 14.65% 1165 1118 -4.09% 1862 1837 -1.36% 2302 2220 -3.56% 53929 49612 -8.01% South 21.94 0.02% 0.01% 2 2 -9.16 3 3 14.74% 1 1 -11.39% 40 53 31.19% Cambridge- shire Total 168266.8 100.00 1117 1099 -10.57% 1607 1496 662.76% 1673 2067 -2.07% 115920 136243 7.55% 8 % 4 2 6 6 4 2 3 2

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3.4 Wildlife The Blackwater estuary and Dengie flats contain habitats that support a variety of important wildlife. Due to this, various areas within the BMPA have been designated as statutory and non-statutory sites for nature conservation, including as a Marine Conservation Zone (MCZ), Special Area of Conservation (SAC) and Ramsar site.

Several of these designations are due to nationally and internationally important populations of overwintering waterbirds. In the five years to 2013, the average overwintering, wildfowl and gull population across the Blackwater estuary and Dengie Flats was 131,438. In the five years to 2018/2019 (the most recent for which data are available), this had increased to 145,456, an increase of 10.6% (Frost et al., 2020). Commonly sighted species include Brent Goose, Shelduck, Avocet and Dunlin. Wading birds forage (and therefore defecate) directly on shellfish beds, although their precise distributions will vary from year to year and therefore it is difficult to make recommendations for RMP location to capture this source of pollution.

In addition to the populations of waterbirds, significant numbers of grey and harbour seals use the area around the BMPA. The most recent population estimate puts the number of grey seals at 3,243 and the number of harbour seals at 932 (Cox et al., 2020). This number has increased by > 180% since 2013. However, these species show wide foraging ranges and as such any contamination is likely to be spatially and temporally variable, and as such will have limited impact on the overall level of bacteriological contamination experienced by the BMPA.

Despite the fact that bird and marine mammal populations have increased significantly since the original sanitary survey was conducted, it remains challenging to accurately account for this source of pollution in any updated sampling plan. No other wildlife species are likely to represent a significant source of contamination and as such the recommendations for RMP location made in the original sanitary survey are still valid.

3.5 Boats and Marinas The discharge of sewage from boats is a potential significant source of bacterial contamination of shellfisheries within the Blackwater BMPA. Boating activities within the area have been derived through analysis of satellite imagery and various internet sources and compared to that described in the original sanitary survey. Their geographical distributions are presented in Figure 3.5.

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Figure 3.5 Locations of moorings, marinas and other boating activities near the Blackwater BMPA.

The area of the BMPA off the Dengie peninsula has very little in the way of boating activity, perhaps due to the wide intertidal area. In contrast to this, the Blackwater estuary experiences a significant amount of recreational boating activity, and is a popular place for commercial fishing. The original sanitary survey reported the presence of about 800 berths at the three main marinas in the estuary, although there are a significant number of swinging half-tide moorings throughout the estuary. None of the marinas in the estuary are equipped with pump-out facilities; the closest are located at the Royal Harbour Marina on the North Kent Coast. Vessels large enough to contain onboard toilets are liable to make occasional overboard discharges, particularly when transiting through the main navigational routes of the estuary or when moored overnight. Peak activity levels are likely to remain in the summer months, and the associated risk of contamination is therefore also highest at these times.

The waters around the BMPA are home to a fishing fleet of about 35 vessels, most < 10 m total length (UK Government, 2020). There have been no changes to the legislation governing overboard discharges from vessels, with restrictions placed on commercial vessels against overboard discharges within three nautical miles of land and guidance given to pleasure craft users to follow the same advice (RYA, 2020).

The main areas at risk of contamination from overboard discharges have not changed significantly, and consultation with the LA did not indicate a significant increase in the extent of shipping activity. The original sanitary survey was not able to make concrete recommendations about RMP locations to capture this source of pollution due to the lack of specific data. The same is true for this review,

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and as such this source of contamination does not carry any additional weighting for consideration in any updated sampling plan. 3.6 Other Sources of Contamination Urban fabric in the catchment remains concentrated several kilometres inland of the shellfisheries, although the town of Maldon is located at the head of the Blackwater estuary. Settlements near to waterbodies represent a potential source of diffuse pollution via utility misconnections and dog fouling. The geographical extent of urban settlements within the catchment have not increased significantly since the original sanitary survey (despite new housing developments), and therefore the risk that these settlements pose remains broadly similar.

The Dengie peninsula remains a popular destination for dog walkers, with several coastal paths following the banks of the estuary. This therefore remains a potential source of diffuse pollution to the near-shore coastal zone, although is expected to be minor. There is no evidence that their use has changed significantly since the original sanitary survey.

No evidence of significant changes to these sources of contamination exists. Therefore, it can be assumed that the RMP location recommendations made in the original sanitary survey will still capture the influence of these sources.

4 Hydrodynamics/Water Circulation The bathymetry presented in the original sanitary survey was recorded during the 1980’s, it is unlikely that any significant changes to the hydrography will have occurred since the original sanitary survey. Tidal currents in the Blackwater estuary flood up the estuary in a westerly direction and ebb in an easterly direction. The Dengie Flats will receive tidal circulation draining from the Blackwater estuary to the north and the Crouch estuary to the south, although current velocities and contamination is likely to be greatest in the main drainage channels. As is described in the original sanitary survey, the intertidal foreshore immediately adjacent to the coast will only be affected by local sources.

Given that the hydrodynamic circulation in the BMPA is considered unlikely to have changed significantly since the original sanitary survey, the recommendations made in that document to capture circulating pollution remain valid.

5 Rainfall Rainfall data for the Blackwater at Langford weather station (NGR: TL835090) from 2010 – 2013 (pre sanitary survey data) and 2014 – 2017 (post sanitary survey data) were used to determine whether any changes in rainfall patterns had occurred since the original sanitary survey. Figure 5.1 shows the average daily rainfall totals for each month at the Langford monitoring station. Whilst rainfall has decreased slightly since the publication of the original sanitary survey, two sample t-tests indicated that there was no significant difference (p = 0.405) between the mean daily rainfall per month between the 2010 – 2013 and 2014 – 2017 period. Table 5.1 summarises the rainfall at the Langford monitoring station for the two periods.

Rainfall leads to increased faecal loading through two factors; elevated levels of surface runoff and spill events from intermittent discharges. However, as the rainfall patterns have remained consistent across the two time periods, significantly increased bacterial loading due to these factors are unlikely

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and as such RMP recommendations made in the original sanitary survey to capture the influence of runoff and spill events remain valid.

Figure 5.1 Mean daily rainfall (mm) per month for the Blackwater at Langford (TL835090) for the period (A) 2010 – 2013 (pre sanitary survey) and (B) 2014 – 2017 (post sanitary survey).

Table 5.1 Summary statistics for rainfall before and after the sanitary survey.

Period Mean Annual % Dry Days % Days Exceeding % Days Exceeding Rainfall (mm) 10 mm 20 mm 2010 - 2013 606.05 44.76 23.27 14.58 2014 - 2017 600.65 42.16 22.18 14.10

6 Microbial Monitoring Results 6.1 Summary Statistics and geographical variation There is a total of 9 Representative Monitoring Points that have been sampled within the Blackwater BMPA since the original sanitary survey. 5 of these are for Pacific oyster (Crassostrea gigas) and 2 are for native oyster (Ostrea edulis) and cockles (Cerastoderma edule) respectively. Only two of these RMPs (Bachelor Spit (B014A and Ramsey Marsh (B014W)) were sampled prior to the original sanitary survey. Sampling at all but one of the additional RMPs began in June and July 2013, with sampling at St Peters Flats South West (B14AD) starting in March 2014. Sampling at Grange Outfall (B014Z) ceased in 2018, though it is not clear what prompted this action. Sampling at the remaining RMPs is ongoing. The geometric mean results of shellfish flesh monitoring for all RMPs sampled since the original sanitary survey are presented in Figure 6.1. Summary statistics are presented in Table 6.1.

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Table 6.1 Summary statistics of E. coli (MPN/100 g) from RMPs sampled from 2003 onwards (data cut off at December 2020).

Site (Species) NGR Species No. First Last E. coli MPN/100 g Sample Sample Geometri Min Max Value % > % > % > c Mean Value 230 4,600 46,000 Bachelor Spit TM08800590 Native 207 24/01/2003 08/12/2020 455.02 18 35000 9.66 1.45 0 (O. ed) - B014A Oyster North Double TL89700620 Pacific 85 31/07/2013 09/12/2020 1055.24 18 14000 45.8 8.24 0 Buoy (C. gi) - Oyster 8 B014U Goldhanger (C. TL91160795 Pacific 90 10/06/2013 09/12/2020 408.48 18 4900 28.8 1.11 0 gi) - B014V Oyster 9 Ramsey Marsh TL93510601 Pacific 89 09/01/2013 09/12/2020 270.63 18 7900 17.9 1.12 0 (C. gi) - B014W Oyster 8 Bradwell (C. gi) TL99540858 Pacific 88 04/06/2013 02/12/2020 74.90 18 790 3.41 0 0 - B014X Oyster Ray Channel (O. TM06440142 Native 89 10/07/2013 08/12/2020 73.12 18 1300 5.62 0 0 ed) - B014Y Oyster Grange Outfall TM04980188 Cockle 54 11/06/2013 23/01/2018 55.31 18 330 3.70 0 0 (C. ed) - B014Z Buxey Sands (C. TM07200080 Cockle 88 11/06/2013 10/11/2020 155.3295 18 4900 9.09 1.14 0 ed) - B14AA St Peters Flats TM04060768 Pacific 80 19/03/2014 02/12/2020 30.6875 18 170 0 0 0 South West (C. Oyster gi) - B14AD

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Figure 6.1 Geometric mean E. coli results from Official Control monitoring at bivalve RMPs within the Blackwater BMPA.

Mean E. coli levels are generally low across at all RMPs, with only one RMP (North Double Buoy, B014U) having a mean value of > 1,000 MPN/100 g. This RMP is also the only one to have returned more than 2% of its results greater than the middle threshold of 4,600 MPN/100 g. Generally, the RMPs in the Blackwater estuary have returned higher E. coli levels than those on the Dengie Flats. There does not appear to be a clear separation by species, although a direct comparison is challenging given the geographical separation between Pacific oyster RMPs and those for cockles and native oysters.

Figure 6.2 - Figure 6.4 present boxplots of E. coli monitoring results for RMPs sampled for Pacific oyster (Figure 6.2), native oyster (Figure 6.3) and cockle (Figure 6.4). One-way analysis of variance (ANOVA) tests indicated that the mean monitoring result at North Double Buoy (B014U) was significantly greater than the results from Goldhanger (B014V) (p < 0.01), Ramsey Marsh (B014W), Bradwell (B014X) and St Peter’s Flats South West (B14AD) (all p < 0.0001). North Double Buoy (B014U) is located farthest up-estuary of any of the Pacific oyster RMPs, perhaps explaining the higher results from this location. The variation was broadly similar across all RMPs with the exception of St Peters Flats South West (B14AD), which had a far smaller interquartile range but a greater number of outliers (results >1.5 x the interquartile range) (Figure 6.2). No significant

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differences were found in either the native oyster (Figure 6.3) or cockle (Figure 6.4) RMPs. Both native oyster RMPs returned a large number of outliers.

Figure 6.2 Boxplots of E. coli levels at Pacific oyster RMPs sampled within the Blackwater BMPA 2013-Present. Central line indicates median value, box indicates lower – upper quartile range and whisker indicates minimum/maximum value excluding outliers (points >1.5 x interquartile range).

Figure 6.3 Boxplots of E. coli levels at native oyster RMPs sampled within the Blackwater BMPA 2003-Present. Central line indicates median value, box indicates lower – upper quartile range and whisker indicates minimum/maximum value excluding outliers (points >1.5 x interquartile range).

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Figure 6.4 Boxplots of E. coli levels at cockle RMPs sampled within the Blackwater BMPA 2013-Present. Central line indicates median value, box indicates lower – upper quartile range and whisker indicates minimum/maximum value excluding outliers (points >1.5 x interquartile range). 6.2 Overall temporal pattern in results The overall temporal pattern in shellfish flesh monitoring results for Pacific oyster, native oyster and cockle RMPs within the Blackwater BMPA are shown in Figure 6.5, Figure 6.6 and Figure 6.7 respectively.

The E. coli levels at Pacific oyster RMPs have been relatively consistent since the original sanitary survey was published (Figure 6.5), although there is a clear trend of increasing E. coli levels in every RMP except for St Peter’s Flats South West (B14AD). Whilst there is overlap in the raw data, the loess trend lines fitted to the data show a distinct pattern; with the trend line from North Double Buoy (B014U) consistently higher than that of Goldhanger (B014V), which is intern higher than Ramsey Marsh (B014W), which is higher than Bradwell (B014X) which is higher again than St Peters Flats South West (B14AD). Comparing this to the geographical position of the RMPs (Figure 6.1), there is a clear trend of decreasing E. coli levels as you move downstream in the Blackwater estuary.

The trend lines of the native oyster RMPs have remained very similar since the original sanitary survey was published (Figure 6.6); with generally low levels of E. coli (significantly below the lower threshold of 230 MPN/100 g) and a slight increase in the last 12 months.

Whilst it was sampled, results from Grange Outfall (B014Z) were generally lower than those from Buxey Sands (B14AA), although there was greater variation. There is a very slight upward trend in results from Buxey Sands (B14AA) in the last 12 months, although only one result has exceeded the middle threshold of 4,600 MPN/100 g since sampling began.

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Figure 6.5 Timeseries of E. coli levels at Pacific oyster RMPs sampled within the Blackwater BMPA 2013 – Present. Scatter plots are overlaid with loess model fitted to data.

Figure 6.6 Timeseries of E. coli levels at native oyster RMPs sampled within the Blackwater BMPA 2003 – Present. Scatter plots are overlaid with loess model fitted to data.

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Figure 6.7 Timeseries of E. coli levels at cockle RMPs sampled within the Blackwater BMPA 2013 – Present. Scatter plots are overlaid with loess model fitted to data. 6.3 Seasonal patterns of results The seasonal patterns of E. coli levels at the various RMPs within the Blackwater BMPA were investigated and are presented in Figure 6.8 - Figure 6.10. The data for each year were averaged into the four seasons, with Winter comprising data from January – March, Spring from April – June, Summer from July – September and Autumn from October – December. Two-way ANOVA testing was used to look for significant differences in the data, using both season and RMP as independent factors (i.e. pooling the database across RMP and season respectively), as well as the interaction between them (i.e. exploring seasonal differences within a given RMP). Significance has been taken at the 0.05 level.

Despite some apparent differences (i.e. at Ray Channel (B014Y) (Figure 6.9)), two-way ANOVA tests did not indicate any significant differences in seasonal levels of E. coli when data were pooled or within RMP for any of the three sampled species (p > 0.5), indicating that seasonal classifications are not appropriate for any of the active CZs.

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Figure 6.8 Boxplots of E. coli levels per season at Pacific oyster RMPs sampled within the Blackwater BMPA 2013 - present.

Figure 6.9 Boxplots of E. coli levels per season at native oyster RMPs sampled within the North Kent Coast BMPA 2013 - present.

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Figure 6.10 Boxplots of E. coli levels per season at cockle RMPs sampled within the Blackwater BMPA 2013 - present. 7 Conclusion and overall assessment No estimate of the current size of this fishery was available through IFCA data or consultation with the LA, although the LA indicated that the current fishery species are Pacific oyster, native oyster and cockles. Consultation indicated that an application to harvest clams at Old Hall Creek is pending, although no current CZs for this species are active. The original sanitary survey also briefly mentions mussel stocks, although indicates that stock levels were low and no commercial harvesting was taking place. CZs in the Blackwater Estuary cover the area between Northey Island and Osea Island to the mouth of the estuary. The CZs on the Dengie flats cover the entire width of the peninsula and 13 km out to the offshore end of Buxey Sands. Osea South, Goldhanger, Central Blackwater, Outer Blackwater, St Peter’s & Bachelor and Ray Channel are all classified for both native and Pacific oysters. St Peter’s Flats is only classified for Pacific oyster harvesting. Additionally, Dengie Flats and Buxey Sands are classified for cockle harvesting.

The total population in Electoral Wards contained within or partially within the Blackwater catchment increase by 7.32% between the 2001 and 2011 censuses (the most recent for which data are available). This population increase has been broadly equal across the catchment, with only 13% of wards showing a decrease. Average population density across the catchment has remained relatively low, at 18.84 persons per hectare (an increase of ~1 person per hectare). Consultation with the Local Authority did not indicate that any significant housing developments have occurred since the original sanitary survey was conducted, although any increase in population without upgrades to the wastewater treatment network would result in an increase in faecal loading to the estuary. Tourism is a key part of the economy in the region, and population numbers increase significantly during summer months which will further increase the load on the sewerage network.

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Consultation with the LA and EA did not indicate any significant upgrades to the wastewater treatment network within operational catchments draining to the waters of the BMPA. Whilst the number of intermittent discharge locations has fallen slightly, no spill event monitoring data is available for comparison. It is assumed that the increase in loading caused by increasing population has been captured in the overheads of the consented discharge volumes. As such, the loading experienced by the estuary may have increase but is not predicted to have changed significantly from that assessed in the previous sanitary survey.

The number of livestock living in Local Authority Districts wholly or partially contained within the Blackwater catchment increased by 4.2% between 2013 and 2016 (the most recent year for which data are available. Livestock densities remain relatively low within the catchment, at 5.19 animals per hectare. Most of the areas of pasture are located away from the Blackwater estuary, although there are some grazing areas on the northern shore, which pose the greatest risk of contamination through land runoff, particularly following extended dry periods. However, the overall risk of this source of pollution remains relatively low.

The BMPA is situated within or near several internationally designated areas for wildlife conservation, including important populations of wading and overwintering birds. The 5-year average count of wading birds has increased by 10.6% for the 5 winters to 2018-2019 (the most recent for which data are available) compared to the 5 winters to 2012-2013. However, the precise distributions of these species are directly related to the distributions of their prey, and as such it is difficult to define the areas most at risk of pollution from avian faeces.

The Blackwater estuary is a popular destination for recreational boaters and supports a small fishing fleet of ~35 vessels. No legislative changes to permitted discharges from commercial or recreational vessels have occurred since the original sanitary survey. As such, occasional overboard discharges by recreational vessels may still occur, with the highest risk time of year during summer months.

A total of 9 RMPs have been sampled within the Blackwater BMPA since the original sanitary survey was published, of which two were sampled prior. E. coli levels from these RMPs generally show a trend of decreasing the farther down the estuary samples are collected from. However, relative to other BMPAs around the country, E. coli levels are generally low, with 4 RMPs having a mean result of less than 230 MPN/100 g (the lowest threshold) and only one having a mean value of >1,000 MPN/100 g. There are no clear differences between species, and given the spatial trend a general approach of selecting RMPs at the up-estuary end of CZs should be taken, unless other point sources are more specific to that location.

No statistically significant seasonal variation in E. coli levels was found at any of the RMPs, both within a given RMP and between RMPs of a certain species. Seasonal classifications are therefore not appropriate for RMPs in this BMPA.

Based on the information available, there do not appear to have been any significant changes to the sources of contamination to this BMPA since the original sanitary survey was published. The authors of this review have not identified any knowledge gaps that would justify a full shoreline survey.

Having reviewed the recommendations of the 2021 report and compared with the findings of the 2013 sanitary survey review for the Blackwater Estuary, the FSA are content that the level of risk posed by the findings is low and there have been minimal changes to the BMPA to warrant changing the location of RMPs, therefore does not warrant a further review of the existing shoreline assessment.

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8 Recommendations 8.1 Pacific oyster The original sanitary survey recommended the classification of 4 CZs, spanning the length of the Blackwater Estuary from between Northea Island and Osea Island to the mouth of the estuary. A further three CZs; one at the mouth of the estuary and two on Dengie flats, were subsequently awarded classifications. Recommendations for these CZs are described below and are summarised in Table 8.1.

Osea South This zone covers the area south of Osea island. Its northern boundary meets the Goldhanger CZ, its eastern boundary meets the Central Blackwater CZ and its western boundary is a line drawn between TL893050 and TL892069. The original sanitary survey recommended classifying this zone from samples taken from Decoy point near to the upstream boundary of the zone. However, based on LA advice, the current RMP is North Double Buoy (B014U), with Pacific oyster suspended in a deployment bag. It is recommended that this RMP be retained as it is considered to be representative of the up-estuary sources, as well as the continuous discharge from Maldon Water Recycling Centre.

Goldhanger This CZ is located immediately north of the Osea South CZ, and meets the Central Blackwater CZ at its eastern boundary. The original sanitary survey recommended classifying this zone using Pacific oyster samples taken from near the Bounds Farm stream drainage channel. The RMP recommended in the original sanitary survey, Goldhanger (B014V), is still in use. It is recommended that a different RMP, closer to the Maldon Water Recyling Centre, be used as this is a likely significant source of contamination to this zone, as the discharge has a relatively high DWF (6,800 m3/day) and only employs secondary treatment.

Central Blackwater This zone is located in the middle of the Blackwater estuary, and is bounded to the west by Osea South and Goldhanger CZs and to the east by the Outer Blackwater CZ. The original sanitary survey recommended classifying this zone using samples taken from the Ramsey Marshes freshwater outfall as this area had the more numerous and varied pollution sources. It is currently classified from this RMP (Ramsey Marshes (B014W)), and it is recommended that this RMP be retained as it is representative of broadscale contamination within the estuary.

Outer Blackwater This CZ meets the Central Blackwater CZ at its western boundary, and extends to a line drawn between TM029089 and TM031114. The northern boundary of this CZ meets the southern boundary of CZs in the West Mersea BMPA. It is currently classified using samples from Bradwell (B014X) RMP, which was recommended in the original sanitary survey to capture the dominating pollution sources in and around Bradwell. It is recommended that this RMP be retained as it is well placed to capture contamination draining down Bradwell Creek from the continuous discharge there.

St Peter’s Flats This CZ was not described in the original sanitary survey, but meets the Outer Blackwater CZ at its western boundary and covers an area of 1106 Ha at the north of the Dengie flats. It is currently classified using samples from the St Peter’s Flats Southwest (B14AD) RMP in the south of the zone. It is recommended that this RMP be retained as it is broadly representative of the main contamination

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sources. Any significant deterioration in up-estuary CZs may warrant investigation of this zone as contamination may be carried down-estuary.

St Peters & Bachelor The original sanitary survey only recommended classifying this zone for native oyster harvesting, although it has been classified for Pacific oysters since 2015. It covers a 3117 Ha area of the Dengie flats. The boundaries of this CZ are slightly different to the native oyster CZ, due to the intersection of this CZ with the St Peter’s Flats CZ. It is currently sampled from the Bachelor Spit (B014A) native oyster, which was recommended to be maintained in the original sanitary survey as it was deemed to be representative of the varied pollution sources affecting this zone. Recommendations for this CZ and RMP are given in the subsequent native oyster section.

Ray Channel This zone covers an area of 2506 Ha, south of the St Peter’s and Bachelor CZ. The boundaries of the CZ are the same as those of the native oyster CZ of the same name. It was originally only recommended for classification for native oyster harvesting, but has been classified for Pacific oyster harvesting since 2015. It is currently sampled using native oyster samples RMP at Ray Channel (B014Y). Recommendations for this CZ and RMP are given in the subsequent native oyster section. 8.2 Native oyster The original sanitary survey recommended the creation of 6 CZs for native oyster harvesting, covering the entire Blackwater estuary and a large area off the Dengie peninsula. All the CZs recommended in the original sanitary survey are still active, and recommendations for them are described below. All the CZs in the Blackwater estuary share boundaries with the Pacific oyster CZs of the same name and are classified based on Pacific oyster samples. Recommendations for those CZs are described above, and only CZs on the Dengie flats (that currently use native oyster RMPs) are described below.

St Peters & Bachelor This CZ covers an area of 3500 Ha in the northern part of the Dengie peninsula. It is slightly larger than the Pacific oyster CZ of the same name, as it covers an area that is classified for Pacific oyster harvesting as the St Peter’s CZ. It has been classified since 2013 using samples from Bachelor Spit (B014A), which is located approximately in the middle of the CZ. It is recommended that this RMP be retained as the hydrography of the flats make this location broadly representative of any contamination originating from the eastern shore of the Dengie Peninsula.

Ray Channel This CZ has the same boundaries as the Pacific oyster CZ of the same name. It is currently classified based on samples from the Ray Channel (B014Y) RMP, which was recommended in the original sanitary survey to capture contamination sources originating from the Dengie shore. It is recommended that this RMP be retained as the hydrography of the flats make this location broadly representative of any contamination originating from the eastern shore of the Dengie Peninsula. 8.3 Cockles No active cockle fishery was in place at the time of the original sanitary survey, although it was scheduled to open later in 2013. The survey recommended two CZs for this species, both of which are still active. Recommendations for these CZs are given below.

Dengie Flats

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This CZ covers an area of 3754 Ha, with the western boundary covering the entire length of the Dengie peninsula’s eastern shore, and extends approximately 3 km out to its eastern boundary with the Buxey Sands CZ. The RMP recommended for classification of this CZ in the original sanitary survey was at Grange Outfall (B014Z), although sampling was suspended at this RMP in January 2018 and since then classification is based on samples from Buxey Sands (B14AA) RMP, which is the RMP for the Buxey Sands CZ. Given the Asheldham Brook drainage channel that cuts through the saltmarsh at the shoreline, it is recommend that if stock exists, the Grange Outfall (B014Z) be reinstated as this would be more representative of the contaminating influences on this zone.

Buxey Sands This CZ is the largest in the BMPA, covering an area of 6236 Ha. Its western boundary meets the Dengie Flats CZ and extends to a maximum distance of 13 km offshore. Based on the hydrography of the area, it was recommended in the original sanitary survey that this zone be classified using samples taken from the Buxey Sands (B14AA) RMP. This RMP is still used, and it is recommended that it be retained as it will be broadly representative of the coastal contamination of this zone. 8.4 Hard clams As of February 2021, three classifications within the Blackwater BMPA are being classified for the harvesting of hard clams (M. mercenaria). These are Goldhanger, Blackwater Central and Blackwater Outer and their boundaries align with the native and Pacific oyster CZs of the same names. It is recommended that these zones be classified using the Pacific oyster RMPs for the Goldhanger and Blackwater Central zones (including the recommended change for Goldhanger), as the filtration rate and bioaccumulation of contaminants of Pacific oysters is equal to or exceeds that of hard clams. 8.5 General Information 8.5.1 Location Reference Production Area Blackwater Cefas Main Site Reference M014 Ordnance survey 1:25,000 Explorer 176 Admiralty Chart 1975 8.5.2 Shellfishery Species Culture Method Seasonality of Harvest Pacific oyster (Crassostrea gigas) Wild & Cultured Year Round Native oyster (Ostrea edulis) Wild & Cultured Open season September - April Cockles (Cerastoderma edule) Wild Year Round 8.5.3 Local Enforcement Authority(s) Name Maldon District Council Princes Road, Maldon Essex CM9 5DL Website https://www.maldon.gov.uk/info/20091/environmental_health Telephone number n/a

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E-mail address n/a

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Table 8.1 Proposed sampling plan for the Blackwater BMPA. Suggested changes are given in red underlined type.

Classification RMP NGR (OSGB Lat/Long RMP

Zone Name 1936) (WGS 1984)

Species Species

Method

Sampling Sampling

Tolerance

Technique

Frequency

Harvesting Harvesting

Represented

Growing Method Growing Sampling Species Sampling

North 51° 43.00’ TL 8970 C. gigas; Osea South B014U Double N, Wild Hand/Dredge Bagged P oyster 10 m Monthly 0620 O. edulis Buoy 00° 44.80’ E C. gigas; Off TL 8926 51°43′55″N , O. edulis; Goldhanger TBC Recycling Wild Hand/Dredge Hand P oyster 100 m Monthly 0725 00°44′22″E M. Centre mercenaria C. gigas; 51° 43.10’ Central Ramsey TL 9351 O. edulis; B014W N, Wild Hand/Dredge Hand P oyster 100 m Monthly Blackwater Marsh 0601 M. 00° 47.90’ E mercenaria C. gigas; 51° 44.42’ P Outer TL 9954 O. edulis; B014X Bradwell N, Wild Hand/Dredge Hand oyster; 100 m Monthly Blackwater 0858 M. 00° 53.33’ E mercenaria St Peter’s 51° 43.84’ Flats TM 0406 St Peter’s Flats B14AD N, C. gigas Wild Hand/Dredge Hand P oyster 100 m Monthly South 0768 00° 57.21’ E West

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Classification RMP NGR (OSGB Lat/Long RMP

Zone Name 1936) (WGS 1984)

Species Species

Method

Sampling Sampling

Tolerance

Technique

Frequency

Harvesting Harvesting

Represented

Growing Method Growing Sampling Species Sampling Monthly 51° 42.78’ N St Peter’s & Bachelor TM 0880 C. gigas; (excl. B014A N, Wild Dredge Dredge oyster; 100 m Bachelor Spit 0590 O. edulis May & 01° 01.26’ E P oyster June) Monthly 51° 40.41’ Ray TM 0644 C. gigas; (excl. Ray Channel B014Y N, Wild Dredge Dredge N oyster 100 m Channel 0142 O. edulis May & 00° 59.06’ E June)

Grange TM 0498 51° 40.69' N Suction Dengie Flats B014Z C. edule Wild Dredge Cockle 100 m Monthly Outfall 0188 00° 57.81' E Dredge

Buxey TM 0716 51° 40.36' N Suction Buxey Sands B14AA C. edule Wild Hand/Dredge Cockle 100 m Monthly Sands 0136 00° 59.68' E Dredge

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9 References Allison, S., Hardy, M., Hayward, K., Cameron, T., & Underwood, G., 2020. Strongholds of Ostrea edulis populations in estuaries in Essex, SE England and their association with traditional oyster aquaculture: Evidence to support a MPA designation. Journal of the Marine Biological Association of the United Kingdom, 100(1), 27-36. doi:10.1017/S0025315419001048.

Creed, R., 2017. Tourism boom worth £189m to Maldon Economy. Available [online] at: https://www.maldonandburnhamstandard.co.uk/news/15004609.tourism-boom-worth-189m-to- maldon-economy/. Accessed January 2021.

Cox, T., Barker, J., Bramley, J., Debney, A., Thompson, D. & Cucknell, A., 2020 Population trends of harbour and grey seals in the Greater Thames Estuary. Mammal Communications 6: 42-51, London.

DEFRA, 2013. Blackwater, Crouch, Roach and Colne Marine Conservation Zone. Available [online] at: file:///D:/Downloads/Blackwater,%20Crouch,%20Roach%20and%20Colne%20MCZ%20Factsheet.pdf . Accessed January 2021.

DEFRA, 2018. Structure of the agricultural industry in England and the UK. Available [online] at: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file /672730/structure-june-eng-localauthority-09jan18.xls. Accessed January 2021.

European Commission, 2012. Community Guide to the Principles of Good Practice for the Microbiological Classification and Monitoring of Bivalve Mollusc Production and Relaying Areas with regard to Regulation 854/2004. Available [online] at: https://ec.europa.eu/food/sites/food/files/safety/docs/biosafety_fh_guidance_community_guide_b ivalve_mollusc_monitoring_en.pdf. Accessed January 2021.

Frost, T.M., Calbrade, N.A., Birtles, G.A., Mellan, H.J., Hall, C., Robinson, A.E., Wotton, S.R., Balmer, D.E. and Austin, G.E. 2020. Waterbirds in the UK 2018/19: The Wetland Bird Survey. BTO/RSPB/JNCC. Thetford.

KEIFCA, 2021. KEIFCA Byelaws: Area A Byelaws. Available [online] at: https://www.kentandessex- ifca.gov.uk/i-want-to-find-out-about/regulations/keifca-byelaws/byelaws-a/. Accessed January 2021.

Office for National Statistics, 2018. National Population Projections (2018 based). Available [online] at: https://www.ons.gov.uk/peoplepopulationandcommunity/populationandmigration/populationproje ctions/bulletins/nationalpopulationprojections/2018based. Accessed January 2021.

RYA, 2020. Waste Management. Available [online] at: https://www.rya.org.uk/knowledge- advice/environmental-advice/Pages/waste-management.aspx.. Accessed January 2021.

UK Government, 2020. UK Fishing Vessel Lists. Available [online] at: https://www.gov.uk/government/collections/uk-vessel-lists. Accessed January 2021.

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Appendices

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Appendix I. Breakdown of population change Total Usual Residents Population Density ID Ward Name 2001 2011 Absolute % 2001 2011 Absolute Census Census Change Change Census Census Change 1 Rochford 6870 7695 825 12.01% 5.99 6.70 0.71 2 Kursaal 8872 11130 2258 25.45% 71.18 89.30 18.12 3 Galleywood 5898 5738 -160 -2.71% 6.59 6.40 -0.19 4 Fryerns 12178 13118 940 7.72% 21.36 23.00 1.64 5 Burnham-on-Crouch North 3805 3713 -92 -2.42% 1.97 1.90 -0.07 6 Ingatestone, Fryerning and Mountnessing 5640 5966 326 5.78% 2.02 2.10 0.08 7 Chelmsford Rural West 2695 2764 69 2.56% 0.45 0.50 0.05 8 Wickford Castledon 7555 7602 47 0.62% 17.34 17.50 0.16 9 St James 6199 6553 354 5.71% 9.99 10.60 0.61 10 Victoria 9346 11004 1658 17.74% 58.11 68.40 10.29 11 Goat Hall 5786 5690 -96 -1.66% 14.61 14.40 -0.21 12 Tillingham 2181 2182 1 0.05% 0.37 0.40 0.03 13 Grange 3366 3739 373 11.08% 41.36 46.00 4.64 14 Boyce 6118 6752 634 10.36% 12.59 13.90 1.31 15 Westborough 10196 10847 651 6.38% 111.18 118.30 7.12 16 Hutton East 3477 3661 184 5.29% 7.15 7.50 0.35 17 St Mary's 6287 6120 -167 -2.66% 26.91 26.20 -0.71 18 Southminster 4021 4272 251 6.24% 1.52 1.60 0.08 19 Wickham Bishops and Woodham 3376 3500 124 3.67% 0.88 0.90 0.02 20 Thorpe 8715 9215 500 5.74% 31.75 33.60 1.85 21 Pitsea South East 11650 11736 86 0.74% 6.62 6.70 0.08 22 Laindon Park 11026 11367 341 3.09% 18.79 19.40 0.61 23 Ashingdon and Canewdon 4208 4514 306 7.27% 0.78 0.80 0.02 24 St. Luke's 10453 11213 760 7.27% 29.75 31.90 2.15 25 Southchurch 9467 9710 243 2.57% 20.35 20.90 0.55 26 St George's 6072 5858 -214 -3.52% 54.15 52.20 -1.95 27 Mayland 3795 4360 565 14.89% 1.43 1.60 0.17

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28 Purleigh 3201 3419 218 6.81% 0.78 0.80 0.02 29 Herongate, Ingrave and West Horndon 3490 3712 222 6.36% 1.76 1.90 0.14 30 Prittlewell 9478 9971 493 5.20% 38.15 40.10 1.95 31 Victoria 5740 5747 7 0.12% 12.13 12.10 -0.03 32 Burnham-on-Crouch South 3954 3958 4 0.10% 16.98 17.00 0.02 33 Hawkwell West 3938 4134 196 4.98% 10.78 11.30 0.52 34 Wheatley 3885 4191 306 7.88% 15.47 16.70 1.23 35 Cedar Hall 5641 5708 67 1.19% 32.37 32.80 0.43 36 Downhall and Rawreth 4057 4843 786 19.37% 3.22 3.80 0.58 37 Nethermayne 11160 11866 706 6.33% 16.52 17.60 1.08 38 Great Baddow East 7853 8377 524 6.67% 17.16 18.30 1.14 39 Hockley West 2008 2096 88 4.38% 4.42 4.60 0.18 40 West Shoebury 10017 10280 263 2.63% 34.93 35.90 0.97 41 Lodge 3974 4088 114 2.87% 28.12 28.90 0.78 42 St Peter's 6391 6409 18 0.28% 15.37 15.40 0.03 43 Chalkwell 9207 10045 838 9.10% 56.82 62.00 5.18 44 Hawkwell North 4369 4536 167 3.82% 29.99 31.10 1.11 45 Billericay West 11934 11964 30 0.25% 22.50 22.60 0.10 46 Hullbridge 6445 6527 82 1.27% 8.22 8.30 0.08 47 South Hanningfield, Stock and Margaretting 5179 5576 397 7.67% 1.19 1.30 0.11 48 Shoeburyness 9974 11159 1185 11.88% 26.20 29.30 3.10 49 South Woodham-Elmwood and Woodville 8133 8087 -46 -0.57% 15.61 15.50 -0.11 50 Eastwood Park 9332 9364 32 0.34% 41.69 41.80 0.11 51 St Laurence 9673 9726 53 0.55% 32.89 33.10 0.21 52 Whitehouse 3728 4048 320 8.58% 23.08 25.10 2.02 53 Leigh 9015 10083 1068 11.85% 59.59 66.60 7.01 54 Bicknacre and East and West Hanningfield 5039 5035 -4 -0.08% 1.50 1.50 0.00 55 Blenheim Park 9908 10475 567 5.72% 43.75 46.30 2.55 56 Rettendon and Runwell 5039 5021 -18 -0.36% 2.17 2.20 0.03 57 Appleton 6681 6694 13 0.19% 40.86 40.90 0.04 58 Langdon Hills 8762 9064 302 3.45% 14.99 15.50 0.51 59 Foulness and Great Wakering 5724 5738 14 0.24% 1.45 1.50 0.05 60 Hockley North 1872 2120 248 13.25% 14.92 16.90 1.98

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61 Vange 9571 10048 477 4.98% 58.22 61.10 2.88 62 Pitsea North West 12901 12722 -179 -1.39% 31.37 30.90 -0.47 63 Burstead 10417 10620 203 1.95% 5.42 5.50 0.08 64 West Leigh 8670 9154 484 5.58% 28.35 29.90 1.55 65 Wickford Park 7965 9537 1572 19.74% 16.49 19.70 3.21 66 Lee Chapel North 12102 13488 1386 11.45% 57.10 63.60 6.50 67 Crouch 7491 8943 1452 19.38% 5.25 6.30 1.05 68 Belfairs 8944 9219 275 3.07% 33.92 35.00 1.08 69 Hawkwell South 3961 4249 288 7.27% 29.24 31.40 2.16 70 Wickford North 11843 12235 392 3.31% 25.44 26.30 0.86 71 Hockley Central 6111 6526 415 6.79% 43.50 46.50 3.00 72 Rayleigh Central 4284 4255 -29 -0.68% 59.30 58.90 -0.40 73 Trinity 3580 3697 117 3.27% 14.29 14.80 0.51 74 St Martin's 7641 8410 769 10.06% 31.67 34.90 3.23 75 Billericay East 11472 11777 305 2.66% 21.55 22.10 0.55 76 Little Baddow, Danbury and Sandon 8091 8285 194 2.40% 2.41 2.50 0.09 77 Sweyne Park 4325 4415 90 2.08% 46.95 47.90 0.95 78 South Woodham-Chetwood and Collingwood 8496 8366 -130 -1.53% 25.63 25.20 -0.43 79 Milton 8990 11063 2073 23.06% 54.80 67.40 12.60 80 Althorne 4002 4128 126 3.15% 1.07 1.10 0.03 81 Barling and Sutton 1784 1876 92 5.16% 0.88 0.90 0.02 82 Writtle 5632 5383 -249 -4.42% 3.12 3.00 -0.12 83 Great Notley and Braintree West 5420 7451 2031 37.47% 13.53 18.60 5.07 84 South Weald 1828 1891 63 3.45% 1.53 1.60 0.07 85 Hatfield Peverel 4384 4376 -8 -0.18% 2.30 2.30 0.00 86 Hutton North 4189 4236 47 1.12% 27.01 27.30 0.29 87 The Three Colnes 4848 5241 393 8.11% 1.74 1.90 0.16 88 Braintree Central 6502 8622 2120 32.61% 32.27 42.80 10.53 89 Heybridge East 3882 4023 141 3.63% 7.54 7.80 0.26 90 Boreham and The Leighs 5093 6306 1213 23.82% 1.58 2.00 0.42 91 Thaxted 3146 3512 366 11.63% 0.81 0.90 0.09 92 Gosfield and Greenstead Green 2460 2465 5 0.20% 0.75 0.80 0.05 93 Bocking South 4978 5796 818 16.43% 19.31 22.50 3.19

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94 Three Fields 3818 3967 149 3.90% 0.59 0.60 0.01 95 Barnston and High Easter 1507 1701 194 12.87% 0.54 0.60 0.06 96 Trinity 5830 6295 465 7.98% 39.94 43.10 3.16 97 Kelvedon 5019 5148 129 2.57% 2.99 3.10 0.11 98 Brizes and Doddinghurst 5923 5958 35 0.59% 1.82 1.80 -0.02 99 Maldon South 4056 4015 -41 -1.01% 23.44 23.20 -0.24 100 Takeley and the Canfields 2939 4716 1777 60.46% 0.97 1.60 0.63 101 St Andrews 8644 9081 437 5.06% 40.59 42.60 2.01 102 The Sampfords 1782 1900 118 6.62% 0.35 0.40 0.05 103 Witham West 6886 6960 74 1.07% 14.58 14.70 0.12 104 Maldon West 4011 3777 -234 -5.83% 14.11 13.30 -0.81 105 Great Dunmow South 4459 4952 493 11.06% 3.55 3.90 0.35 106 Felsted 3153 5525 2372 75.23% 1.02 1.80 0.78 107 Panfield 2036 2063 27 1.33% 0.74 0.80 0.06 108 Shenfield 5144 5432 288 5.60% 7.52 7.90 0.38 109 Witham South 6154 9018 2864 46.54% 15.98 23.40 7.42 110 The Eastons 1489 1577 88 5.91% 0.52 0.50 -0.02 111 Great Baddow West 5164 6273 1109 21.48% 27.10 32.90 5.80 112 Marconi 6306 7401 1095 17.36% 44.35 52.10 7.75 113 Patching Hall 8776 8939 163 1.86% 44.10 44.90 0.80 114 Bocking North 4215 4728 513 12.17% 3.44 3.90 0.46 115 High Ongar, Willingale and The Rodings 2081 2237 156 7.50% 0.45 0.50 0.05 116 Pilgrims Hatch 5908 5963 55 0.93% 12.57 12.70 0.13 117 Maldon North 3812 4239 427 11.20% 8.87 9.90 1.03 118 Springfield North 8999 8807 -192 -2.13% 32.22 31.50 -0.72 119 Brentwood South 5099 5789 690 13.53% 28.89 32.80 3.91 120 Great Tey 2764 2695 -69 -2.50% 0.75 0.70 -0.05 121 Warley 5662 5973 311 5.49% 3.10 3.30 0.20 122 Elsenham and Henham 3602 3679 77 2.14% 1.56 1.60 0.04 123 Broomfield and The Walthams 7477 8063 586 7.84% 1.68 1.80 0.12 124 Rayne 2162 2299 137 6.34% 2.55 2.70 0.15 125 Bradwell, Silver End and Rivenhall 4985 5112 127 2.55% 2.05 2.10 0.05 126 Coggeshall and North Feering 4778 5201 423 8.85% 1.61 1.80 0.19

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127 Waterhouse Farm 4985 6319 1334 26.76% 22.96 29.10 6.14 128 Hutton South 3786 3826 40 1.06% 21.74 22.00 0.26 129 Witham North 5018 4809 -209 -4.17% 21.09 20.20 -0.89 130 Braintree East 6118 7557 1439 23.52% 32.89 40.60 7.71 131 The Rodings 1755 1853 98 5.58% 0.53 0.60 0.07 132 Moulsham Lodge 5484 5624 140 2.55% 49.97 51.30 1.33 133 Black Notley and Terling 3298 4054 756 22.92% 0.82 1.00 0.18 134 Bocking Blackwater 7962 8183 221 2.78% 39.34 40.40 1.06 135 Hutton Central 3674 3855 181 4.93% 16.86 17.70 0.84 136 Great Dunmow North 2537 3878 1341 52.86% 2.36 3.60 1.24 137 The Lawns 5610 5402 -208 -3.71% 31.95 30.80 -1.15 138 Witham Chipping Hill and Central 4412 4566 154 3.49% 14.46 15.00 0.54 139 Wimbish and Debden 2303 2407 104 4.52% 0.63 0.70 0.07 140 Stebbing 1510 1560 50 3.31% 0.59 0.60 0.01 141 Tipps Cross 3830 3807 -23 -0.60% 2.51 2.50 -0.01 142 Heybridge West 3745 4152 407 10.87% 22.30 24.70 2.40 143 Maldon East 2155 2189 34 1.58% 6.31 6.40 0.09 144 Chelmer Village and Beaulieu Park 8406 11277 2871 34.15% 15.61 20.90 5.29 145 Brentwood North 5919 6485 566 9.56% 33.37 36.60 3.23 146 Cressing and Stisted 2155 2311 156 7.24% 0.94 1.00 0.06 147 Great Totham 3463 3660 197 5.69% 1.14 1.20 0.06 148 Moulsham and Central 8457 10201 1744 20.62% 30.24 36.50 6.26 149 Braintree South 6535 7477 942 14.41% 36.16 41.40 5.24 150 West Mersea 6925 7183 258 3.73% 6.52 6.80 0.28 151 Pyefleet 2435 2596 161 6.61% 0.61 0.70 0.09 152 Balsham 4465 4682 217 4.86% 0.46 0.50 0.04 153 Ashdon 1601 1736 135 8.43% 0.50 0.50 0.00 154 Birch and Winstree 4846 5651 805 16.61% 0.77 0.90 0.13 155 Tollesbury 2033 1977 -56 -2.75% 1.68 1.60 -0.08 156 Copford and West Stanway 1876 1915 39 2.08% 1.70 1.70 0.00 157 Tolleshunt D'Arcy 3926 4065 139 3.54% 0.83 0.90 0.07 158 Tiptree 7516 7583 67 0.89% 9.02 9.10 0.08 159 Marks Tey 2566 2551 -15 -0.58% 4.21 4.20 -0.01

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Total 905002 971269 66267 7.32%

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Appendix II. Blackwater Sanitary Survey Report 2013

Follow hyperlink in image to view full report.

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About Carcinus Ltd Environmental Consultancy Carcinus Ltd is a leading provider of aquatic Carcinus provides environmental consultancy services for environmental consultancy and survey services in the UK. both freshwater and marine environments. Our freshwater and marine environmental consultants Carcinus was established in 2016 by its directors after provide services that include scoping studies, over 30 years combined experience of working within the Environmental Impact Assessment (EIA) for ecological marine and freshwater environment sector. From our and human receptors, Habitats Regulations Appraisal base in Southampton, we provide environmental (HRA), Water Framework Directive (WFD) assessments, consultancy advice and support as well as ecological, project management, licensing and consent support, pre- topographic and hydrographic survey services to clients dredge sediment assessments and options appraisal, throughout the UK and overseas. stakeholder and regulator engagement, survey design and management and site selection and feasibility Our clients operate in a range of industry sectors studies. including civil engineering and construction, ports and harbours, new and existing nuclear power, renewable Ecological and Geophysical energy (including offshore wind, tidal energy and wave energy), public sector, government, NGOs, transport and Surveys water. Carcinus delivers ecology surveys in both marine and freshwater environments. Our staff are experienced in Our aim is to offer professional, high quality and robust the design and implementation of ecological surveys, solutions to our clients, using the latest techniques, including marine subtidal and intertidal fish ecology and innovation and recognised best practice. benthic ecology, freshwater fisheries, macro invertebrate sampling, macrophytes, marine mammals, birds, habitat Contact Us mapping, River Habitat Surveys (RHS), phase 1 habitat surveys, catchment studies, water quality and sediment Carcinus Ltd sampling and analysis, ichthyoplankton, zooplankton and phytoplankton. Wessex House In addition, we provide aerial, topographic, bathymetric Upper Market Street and laser scan surveys for nearshore, coastal and riverine environments. Eastleigh

Hampshire Our Vision “To be a dependable partner to our clients, SO50 9FD providing robust and reliable environmental Tel. 023 8129 0095 advice, services and support, enabling them to achieve project aims whilst taking due care of the Email. [email protected] sensitivity of the environment”

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