An audit of the surface water outfalls in the Ravensbourne - ‘Outfall Safari’

December 2017

UK & Europe Conservation Programme Zoological Society of

Regent's Park

London, NW1 4RY [email protected] www.zsl.org/conservation/regions/uk-europe/london’s-

Acknowledgements

This project, funded by The Rivers Wetlands and Community Days Fund and City Bridge Trust, has been delivered in partnership with Thames21 with the support of the Environment Agency and Thames Water. It would not have been possible without the help of all the dedicated volunteers who collected the data.

Introduction

Misconnected wastewater pipework, cross-connected sewers and combined sewer overflows are a chronic source of pollution in urban rivers. An estimated 3% of properties in are misconnected (Dunk et al., 2008) sending pollution, via outfalls, into the nearest watercourse. There is currently no systematic surveying of outfalls in rivers to identify sources of pollution and to notify the relevant authorities. The ‘Outfall Safari’ is a survey method devised to address this evidence gathering and reporting gap. It was created by the Citizen Crane project steering group which consists of staff of Thames Water, Environment Agency (EA), Crane Valley Partnership, Friends of River Crane Environment, Frog Environmental and the Zoological Society of London (ZSL). It was first used on the River Crane in May 2016.

Aims

The aims of the Outfall Safari were to:

 Record and map the dry weather condition behaviour of surface water outfalls in the Ravensbourne catchment rivers;  Assess and rank the impact of the outfalls and report those that are polluting to the Environment Agency and Thames Water;  Build evidence on the scale of the problem of polluted surface water outfalls in Greater London; and  Recruit more volunteers and further engage existing volunteers in the work of the Ravensbourne Catchment Partnership.

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Method

The survey of outfalls was conducted between 11th October and 9th November 2017. In total, 23 trained volunteers took part in the Outfall Safari. Volunteers were trained at the Arts Café in Manor Park. Training, delivered by ZSL, Thames21 and Thames Water included:

 An overview of water quality issues in the River Ravensbourne;  Information on outfalls and how they become polluted;  Information on Thames Water’s surface water outfall team;  Instruction on how to assess each outfall using the project App and how to upload information to the database; and  A health and safety briefing and signing of the risk assessment.

During the training, volunteers were assigned lengths of the River Ravensbourne to survey. Further coordination of survey dates and reaches was conducted by the volunteers on a closed Facebook group set up specifically for the Outfall Safari. Groups of volunteers were free to conduct the survey of their reach when convenient to them, within the survey period, provided there had been no rain for 48 hours prior to survey. A period of 48 hours of no rain is required before any survey work as rainfall and high surface water flows can obscure the negative impacts of outfalls by washing away sewage fungus, discoloured sediments and rag. Approximately 28.7km of the River Ravensbourne was surveyed by the Outfall Safari in total. Of this, 25.25km was surveyed by Thames21 and volunteers and 3.45km was surveyed by the Environment Agency (see Figure 1).

Typically, the majority of the survey work for an Outfall Safari would be conducted from the riverside path, with only the occasional need to enter the river to properly assess and photograph outfalls. This is because Outfall Safari surveys are generally led by volunteers only, working in pairs (as a minimum) or groups. However, for the River Ravensbourne Outfall Safari volunteers were accompanied by Thames21 staff on surveys, as well as ZSL staff on some occasions. In these cases, and where river depths were low enough, surveys were conducted in- channel.

The risk assessment for riverside outfall surveying highlighted the need to assess conditions in the river before entering it and stressed that volunteers should only enter the river channel if the level was lower than Wellington boot depth (c. 35cm). During the training volunteers were

13 also shown images of Giant Hogweed (Heracleum mantegazzianum). It was essential that volunteers could identify Hogweed before undertaking any survey work as it is a relatively common plant along the banks of rivers in Greater London and can burn and blister skin if touched. Waders and stabilising poles were used by in-channel survey teams.

In addition to personal protective equipment (PPE) volunteers took a printed handout, designed to help with ranking the impacts of each outfall, and a smart phone or tablet loaded with a specially created data entry app.

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Key –

A Section A: Creek mouth to Deptford Bridge (TQ 37804 A 77753 to TQ 37426 77022) Section B: Deptford Bridge to Lewisham town centre (TQ 37416 B B F 76890 to TQ 38156 75895) Section C: Lewisham town centre to , South Circular (TQ C 38142 75774 to TQ 37327 73569) G Section D: River Pool, South Circular to Southend Lane (TQ 37257 73384 to TQ 36965 71652) Section E: Southend Park to Cator Park (TQ 37051 71446 to TQ

D H 36385 69987 and to TQ 36620 70047) I Section F: , Lee High Road to Cator Park (TQ 38403 75574 to TQ 40891 75026) Section G: Tudway Road to Dowding Drive (TQ 40968 74972 to TQ 41254 74703) E Section H: South Circular to Meadows (TQ 41302 74597 to TQ 41026 71834) Section I: River Ravensbourne, Linear Park to Ravensbourne Avenue (TQ 37276 73045 to TQ 39282 69556) O J Section J: Recreation Road to Glassmill Lane (TQ 396151 69268 to TQ 39844 69121) K Section K: Westmoreland Road to Hayes Road (TQ 40321 68500 Q to TQ 40424 68091) P L Section L: B265 to London South East Colleges, (TQ M 40614 67928 to TQ 41448 67176) N Section M: to Turpington Lane (TQ 41884 67258 to TQ 42117 67032) Section N: Crofton Road to Sparrow Drive (TQ 44105 65854 to TQ Legend River Surveyed 44383 66386) Section O: Clock House to (TQ 36434 69457 to TQ 35917 68455 and TQ 35618 68724) Figure 1 – Map of Area of River Ravensbourne Surveyed Section P: Stone Park Avenue to Langley Sports Ground (TQ 37669 68424 to TQ 37692 67331) Section Q: Chaffinch Brook, railway to Fairford Avenue (TQ 35806 67936 to TQ 36039 67603)

The App For ease of data collection from the river, the volunteers used an app created in Epicollect 5 (five.epicollect.net). Created by researchers at Imperial College, Epicollect is free and openly available. Once a project is set up in Epicollect it provides an app for remote data collection and upload, usable on GPS enabled smart phones, and a web portal to access and download the data. The outfall assessment form created in the app consisted of ten questions for volunteers to fill in at each outfall. The questions are taken directly from the form that Thames Water use for assessing the impact of outfalls and are shown in Table 1.

Table 1 – Questions used in the Epicollect app to assess each outfall and their corresponding Impact Score

Question Options EA score 1. Volunteer name 2. Date of survey 3. GPS location 4. Photo of the outfall 5. Description of the nearest landmark 6. Which bank is the outfall on (when looking downstream) 7. Ranking of the flow coming out of the outfall a. No Flow b. Trickle c. Low Flow d. Moderate Flow e. High Flow 8. Ranking of the visual impact of the outfall a. No visible effect 0 b. Within 2m of outfall 2 c. Impact 2 to 10m 4 d. Impact 10 to 30m 6 e. Impact greater than 30m 10 9. Ranking of the aesthetics of the outfall a. No odour or visible aesthetics 0

b. Faint smell, slight discolouration 2 c. Mild smell, mild discolouration, small 4

coverage of sewage fungus d. Strong smell, strong discolouration, large 6

coverage of sewage fungus and/ or litter e. Gross smell, gross sewage 10 10. Other signs of pollution

Conversion of Outfall Assessment to Impact Scores

To assist with prioritisation of the outfalls, the Environment Agency provided a method of converting the assessment data to a numeric impact score for each outfall. These scores are shown in the right hand column in Table 1.

Reporting

Volunteers are advised at the time of training that any outfall with an impact score ≥ 10, from the options in questions 8 and 9, should be reported directly from the river to the Environment Agency’s Incident Hotline and Thames Water. Both Thames Water and Environment Agency also receive a copy of this report.

Data Processing

Outfall data were checked to remove double entries and longitude and latitude coordinates were converted to National Grid References using www.gridreferencefinder.com.

Results The volunteers photographed, located and assessed a total of 198 outfalls. Of this total 73 showed some signs of pollution and scored ˃ 0 and of these 38 had a score ≥ 4. The details of 31 outfalls with an impact score of ≥ 4 are given in Table 2.

Six outfalls that volunteers scored ≥ 4 have not been included in Table 2 for further investigation (photo ID numbers 36, 60, 61, 122, 191 and 193). Those outfalls showed accumulations of a red-brown ‘slime’ (see Figure 2) that is likely to be a bacteria that proliferates by oxidising iron in the water (‘iron mould’) and is not related to misconnections.

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Figure 2 - Examples of ‘Iron Mould’ Around Outfalls on the River Ravensbourne

One outfall (photo ID number 150), located on the left bank near to 32 Lane, SE12 9AN (TQ 41216 73656), is not included in Table 2 either as the pollution assessment indicated the presence of oil, rather than pollution as a result of a misconnection (impact score 4) (see Figure 3).

Figure 3 – Oil Pollution near to Mottingham Lane

Two outfalls that scored ≥ 10 were reported to the Environment Agency from the river and the reference numbers of those reports are included below (see points one and two). Those two outfalls were also reported to Thames Water on 30th November 2017. Details of an additional two outfalls that scored ≥ 10 but had not been reported at the time of survey were passed on to both the Environment Agency and Thames Water on 28th November 2017 and 30th November 2017, respectively (see points three and four). One further outfall that scored ≥ 10 but had also not been reported from the river was reported to Thames Water and the Environment Agency on 13th December 2017 (see point 5). The location and impact score of all five outfalls is included in Table 2 below.

1. Country Park, photo ID number 55, Environment Agency reference 1564670, Thames Water reference 71130789777

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2. Croydon Road (A232), photo ID number 40, Environment Agency reference 1563571, Thames Water reference 71130787904 3. Lennard Road Bridge, photo ID number 189, Environment Agency reference 1570730, Thames Water reference 71130790012 4. Sydenham Cottages, photo ID number 164, Environment Agency reference 1570728, Thames Water reference 71130790532 5. Farnaby Road, photo ID number 200, Environment Agency reference 1573123, Thames Water reference 71213787204

The full 2017 River Ravensbourne Outfall Safari dataset is available from ZSL.

Table 2 – Details and photos of River Ravensbourne outfalls with an impact score of ≥ 4

Photo Bank Outfall ID Location Details NGR Photo Side Score Number

End of the River Pool, at TQ confluence with the River 17 37279 Right 8 Ravensbourne, near to Pool 73042 Court, SE6 3JQ

Near to University Hospital TQ 34 Lewisham, Albacore Crescent, 37748 Right 4 SE13 7HR 74604

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Near to 2 Ormonde Avenue, TQ 5m downstream from Crofton 38 44096 Left 4 Road (A232) bridge, 65857 , BR6 8JP

Near tennis court next to TQ , near 39 41045 Right 4 Amblecote Road and Meadow 71973 Lane, SE12 9TE

Crofton Road culvert, 207-213 TQ 40 Crofton Road (A232), 44104 Left 10 Orpington, BR6 8PT 65849

South Norwood Country Park,

top of West Chaffinch Brook, TQ 55 100m upstream of tram stop, 35072 Right 12 near to Harrington Road, SE25 68390 4NE

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TQ Southend Park, near 105-115 64 37045 Right 6 Meadowview Road, SE6 3NH 71447

Royal Bank of Scotland Sports Ground, between Copers TQ 73 Cope Road and Worsley 36959 Right 6 Bridge Road, , BR3 71099 1RL

TQ 96 42 Dermody Road, SE13 5HB 38823 Left 4 74981

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TQ 103 86 Manor Lane, SE13 5QP 39349 Right 4 74715

TQ Near Manor Lane bridge, 88 104 39342 Left 4 Manor Lane, SE12 8LR 74699

South-west part of Manor TQ 105 House Gardens, near to 63 39367 Left 6 Manor Lane, Lee, SE12 8LN 74733

17

Osborne House, near 78 TQ 111 Meadowcourt Road, 39889 Left 6 No photo available Blackheath, SE3 9DP 75157

TQ Near to 19 Bamford Road, 120 38659 Right 4 Bromley, BR1 5QP 71438

18

Downham Stream, near 1 TQ 124 Cress Mews, Bromley, BR1 38713 Right 4 4LU 71378

Between Westhorne Avenue TQ and Palace Road, near 132 41402 Right 4 442 Westhorne Avenue, SE9 74396 5LT

South Circular, near 465 TQ 135 Westhorne Avenue, Lee, SE9 41357 Left 4 5LR 74463

TQ Near to 182 Eltham Road, SE9 139 41310 Right 4 5LN 74601

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TQ Under bridge near to 128 141 41032 Right 4 Eltham Road, SE9 5LW 74695

TQ 44 Mottingham Lane, SE12 146 41192 Left 6 9AW 73550

Sydenham Cottages, near to TQ 164 72 Edward Tyler Road, SE12 41139 Left 20 9QF 72662

TQ 169 156 Marvels Lane, SE12 9PG 41066 Left 4 72475

20

Bromley Lawn Tennis and TQ 172 Squash Rackets Club, near to 40424 Right 6 65 Hayes Road, BR2 9AE 68090

TQ Kangley Bridge Road, SE26 183 36686 Left 4 5BW 70936

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Near to industrial building TQ 184 complex, Kangley Bridge 36719 Left 4 Road, SE26 5BW 70976

TQ Bridge near to 173 Lennard 189 36461 Right 16 Road, Beckenham, BR3 1QN 70419

TQ Cator Park, near to Capital 192 36454 Right 4 Ring, Beckenham, BR3 1LL 70193

TQ Near 188 Farnaby Road, 200 38944 Right 10 Bromley, BR2 0BB 70050

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Shortlands Golf Course, near TQ 201 146 Ravensbourne Avenue, 38969 Left 4 Bromley, BR2 0AY 69925

Shortlands Golf Course TQ 204 (upstream), near 47 Meadow 39294 Right 4 Road, Bromley, BR2 0DX 69555

Shortlands Golf Course TQ (upstream), near 100 205 39080 Right 4 Ravensbourne Avenue, 69711 Bromley, BR2 0AX

Discussion

This Outfall Safari surveyed approximately 28.7km of the River Ravensbourne and found 31 polluting outfalls (score of ≥4) (excluding outfalls with ‘iron mould’ and pollution unrelated to misconnections). This is approximately 16% of all outfalls assessed, which is comparable to the proportion of polluting outfalls on other London catchments including the River Pinn and River 23

Ingrebourne. The consistently high number of polluting surface water outfalls that have been reported through the Outfall Safaris to date demonstrates the likely scale of the problem across London. The findings of this report further support the need to increase efforts to properly address this pollution source which compromises the ecological value of rivers in London.

Some outfalls pollute intermittently and may not have been detected as a problem during the survey but this report represents an audit of how outfalls, within the surveyed area, were behaving during the survey. Outfalls could intermittently cause more serious problems than impact scores may suggest depending on what was observed at the time of the Outfall Safari survey.

A small number of outfalls that were observed during the Outfall Safari with no flow were not recorded on the app, including some outfalls that showed signs of pollution. The correct methodology for the Outfall Safari was clarified by ZSL staff once this became apparent. However, as a result the number of outfalls requiring further investigation is likely to be slightly underrepresented.

In addition, a small number of outfalls were recorded on the app as a single entry but with a note referring to multiple outfalls (two, four or six outfalls) i.e. there were a number of similar pipes in close proximity that were uploaded as a single entry (or outfall) to the app. Photographs of only one of the outfalls in each of these cases were uploaded to the app. It was therefore not possible, at the data analysis stage, to determine if those multiple pipes were part of a single outfall structure or entirely separate outfalls altogether. These outfalls were analysed as single structures, it is therefore possible that the number of outfalls assessed is underrepresented.

A number of polluting outfalls that were in need of urgent attention (score of ≥ 10) and should have been reported directly to Thames Water and the Environment Agency from the river at the time of the survey were only reported later, at the time of writing this report. Reluctance to report from the river has also been a problem on other Outfall Safaris. As the highest scoring polluting outfalls these have the greatest potential to cause damage to the ecology of the river and any delays to remediate these increase the risk of damage. For any future outfall surveys

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ZSL will make the reporting protocols during volunteer training clearer and add a clearer prompt in the app that reminds the user to report an outfall that scores ≥ 10.

The draft results of this Outfall Safari and the preceding five Outfall Safaris are presented collectively in one London-wide report, published November 2017, which includes recommendations to reduce existing and prevent future misconnections.

References

Dunk, M.J., McMath, S.M., Arikans, J., 2008. A new management approach for the remediation of polluted surface water outfalls to improve river water quality. Water Environ. J. 22, 32–41.

Contact details

Joe Pecorelli: Project Manager – Conservation Programmes [email protected]

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