Outfall Safari
Forth Rivers Trust
In 2022 Forth Rivers Trust started carrying out the Outfall Safari citizen science project for the first time in Scotland on rivers in the Forth catchment.
Outfall Safari was originally created for the River Crane, a tributary of the Thames in West London, which has suffered from some major pollution issues in recent years. The project was created by Crane Valley Partnership, the Environment Agency, Thames Water, the Zoological Society of London and the Friends of River Crane Environment. It was first run in 2016 on the River Crane and has since taken place on many other rivers in Greater London and beyond.
Outfall Safari is a citizen science method used survey a river and record all the outfalls that flow into it. Volunteers locate and assess the impact of polluting outfalls in our rivers and report them if necessary. Using a bespoke survey on the ArcGIS Survey123 app, volunteers go out in pairs and survey a 1-2km stretch of the river once over a two-month period, after a period of at least 24 hours of no rainfall. The location of outfalls is recorded, and the outfall is then assessed and given a score from 0 - 20 based on the signs of pollution that are found.
As Forth Rivers Trust completes more Outfall Safaris, this page will be updated with the results.
CSOs - Forth Catchment
Below is a map of CSOs (Combined Sewer Overflows) in the Forth catchment.
CSO Map for Forth Catchment
Midlothian Esks Outfall Safari
Sept 2022 - Oct 2022 - Volunteer training and recruitment
Nov 2022 - Jan 2023 - Survey period
Jan 2023 - Feb 2023 - Story map production
Many thanks to our funder:
- Esmee Fairbairn Foundation
As part of the Citizen Esk project Forth Rivers trust supported local people in carrying out an Outfall Safari (OS) on the Lothian Esk river. This survey ran over 8 weeks at the end of 2022 into 2023. A total of 61 outfall features were identified and surveyed, 20 of the features were identified as combined sewage outfalls (CSO’s), 15 of which matched up with known locations of CSO’s provided to Forth Rivers Trust by Scottish Water. The other 5 did not match the provided Scottish Water CSO locations and they may be infrastructure operated by other service providers, such as Transport Scotland or National Rail.
Of the five outfalls that scored above one on the aesthetic rating 3 showed signs of sewage related pollution, the other 2 of were identified as surface water drains that had scored badly due to unique factors affecting them. For instance, one turned out to be an outfall showing signs of mine water discharge and not sewage pollution at all.
Full Survey Area
13 trained volunteers took part and surveyed a total of 18km of the Esk river catchment. This breaks down into:
- 4Km of the lower Esk from it's mouth at the Forth up to the meeting point (confluence) of the North and South Esks.
- 12Km of the South Esk upstream of the confluence.
- 2Km of the North Esk upstream of the confluence.
This point on the South Esk is the furthest upstream outfall surveyed. You can see Gorebridge at the bottom of the map. This location is about 16km upstream from the Forth estuary.
There is a CSO At this location which showed some signs of rag waste. In addition the hinged flap did not appear to be properly shut despite the outfall not being in use.
Many of the survey points at this location turned out to be culverts carrying water under the footpaths to the river. This is a good indicator that our volunteers were very diligent at spotting potential outfalls and surveying them.
The outfall marked in green scored a 2 due to a combination of discolouration of the water and signs of signs of rag waste. The next outfall downstream also scored a 2 due to a combination of slight discolouration and odour.
This orange survey point rated a 4 on our survey but when FRT staff checked the location they found that mine water discharge was causing iron eating bacteria to building up on the riverbed. This looks like bright orange/brown gunk which the surveyors had misidentified as a sign of sewage.
The yellow point scored poorly because the water discharging from it was slightly cloudy, it was deemed to be a surface drain for the nearby road.
The outfall, marked in green, scored a 2 due to slight discolouration. In addition to scoring each outfall our surveyors are able to take notes and pictures linked to each location. Here they noted that a lot of rubbish had been dumped on the banks above this location.
Unsurprisingly there were lots of outfall pipes in Musselburgh, 20 survey points were recorded between Inveresk Weir and the mouth of the Esk. 6 of these correspond with known CSO's locations whilst the other 14 were identified as surface water drainage.
These are the furthest survey points downstream that our volunteers managed to gather data for. Despite our best efforts some outfall locations will have been missed due to accessibility issues and difficulties in spotting them. If you click the button below you can see the location of two CSO's that may have been covered by the tide and that may have been impossible for our volunteers to survey.
River Almond Outfall Safari
River Almond phase 1 - Whitburn to East Calder
January - February 2022 - Volunteer recruitment and training period
March - April 2022 - Survey period
June - July 2022 - Report and map production
Many thanks to all our funders:
- Generous donations from members of the public
- The Big Give Green Match Fund
- West Lothian Council
Thirty-five volunteers have worked with Forth Rivers Trust to survey 22.5km of the River Almond, from Polkemmet Country Park (Whitburn) to Almondell & Calderwood Country Park (East Calder). Volunteers were members of River Almond Action Group, a local group created in 2021 by the community to tackle some of the issues in the River Almond, predominantly the sewage being discharged into the river via the Wastewater Treatment Works and multiple CSOs. Other volunteers are members of Friends of Almondell & Calderwood Country Park, and other members of local communities interested in helping investigate the outfalls that discharge into the River Almond.
122 outfalls were recorded, of which 19 showed some signs of pollution at the time of surveying. The results of the survey can be seen below. Click on an individual outfall to view the outfall score, which bank it is on, and a photograph.
Full Survey Area
- 22.5km of river surveyed (47% of total length)
- 17 outfalls were recorded as having impact scores of 1-5;
- 2 had scores of 6-9;
- 0 outfalls scored greater than 10.
28 outfalls were recorded in Polkemmet Country Park, most appearing to be drainage outfalls from the surrounding agricultural land.
This section of the Almond running alongside the M8 motorway also passes the Whitburn Wastewater Treatment Works. Two of the outfalls adjacent to the WWTW showed signs of rag waste during the surveying period.
The section that flows towards St Kentigerns Academy has two outfalls showing signs of rag waste. One of the highest scoring outfalls was found just downstream of the Academy.
This section between Blackburn and Seafield has 12 outfalls, including CSOs adjacent to Blackburn Wastewater Treatment Works, one of which had rag waste present during the survey.
The stretch of river from the west end of Livingston has a mixture of surface water outfalls, retaining wall ground water outfalls, and combined sewer overflows.
As the river passes through Howden in Livingston, there are again a mixture of outfall types, with several showing some evidence of pollution.
The section by Wallace Mill Gardens has a high density of outfalls - mostly surface water outfalls from the housing estates. Downstream of East Calder Wastewater Treatment Works was one of the highest scoring outfalls, with signs of sewage fungus and a very strong odour.
The stretch of river alongside the WWTW wasn't surveyed due to access limitations from construction work taking place.
Full Survey Area with CSOs
Click on the red markers to see details of the outfalls
River Leven Outfall Safari
February - March 2022 - Volunteer recruitment and training period
April - May 2022 - Survey period
June - July 2022 - Report and map production
Many thanks to our funders:
The Outfall Safari on the River Leven was included in SEPA’s Regulators’ Pioneer Fund project as part of the Leven Programme.
"This project has been made possible by a grant from the £3.7 million Regulators’ Pioneer Fund launched by the Department for Business, Energy and Industrial Strategy (BEIS). The fund enables UK regulators and local authorities to help create a UK regulatory environment that unleashes innovation and makes the UK the best place to start and grow a business."
A total of 12 volunteers recruited from local communities along the river have worked with Forth Rivers Trust staff to survey 25km of the River Leven, from the source at Loch Leven to the mouth in Leven. A total of 62 outfalls were recorded, of which 13 showed signs of pollution at the time of surveying. The results of the survey can be seen below. Click on an individual outfall to view the score, which bank it is on, and a photograph.
Full Survey Area
- 25km of river surveyed
- 62 outfalls surveyed
- 13 outfalls were recorded as having impact scores of 1-5
- 0 outfalls were recorded in the upper two pollution categories
From the source at Loch Leven, six outfalls were recorded in the long canalised section of the river, one of which was showing signs of pollution. These outfalls appear to be drainage from the surrounding agricultural land.
The section of river which comes out of the straghtened section as it passes Leslie has five outfalls identified, including one showing signs of rag waste.
As the Leven passes Riverside Park in Glenrothes many outfalls can be seen. While most seem to be surface water outfalls, one by the footbridge beside the B969 showed signs of pollution including rag waste.
The river heads west through Markinch, and several surface water outfalls can be seen. Under the B9130 bridge is an outfall that appear to be ground drainage, but rag waste was found around the outfall, suggesting a possible sewer misconnection.
As the river passes between Windygates and Methilhill, two outfalls below the A915 showed some evidence of pollution, and signs of rag waste was found by a CSO further downstream. The river was inaccessible upstream of here as it passes through the Diageo Biomass Energy Project.
On the final stretch of the Leven, one outfall had water discolouration, sewage fungus and a strong smell. Investigation of this outfall since found the issue to be worse, with extensive signs of pollution coming from the outfall. It was reported to SEPA for further investigation.
Full Survey Area with CSOs
Click on the red markers to see details of the outfalls
Future Outfall Safaris
Forth Rivers Trust hopes to be able to continue to use the Outfall Safari methodology on further rivers in the Forth catchment. It is hoped that eventually all of the major rivers could have their outfalls mapped and assessed. On the Almond the upper and lower reaches still need to surveyed as does the upper reaches of the Esk. Additionally, our volunteers have suggested that carrying out Outfall Safaris on the tributaries of all three rivers would be highly beneficial in creating complete pictures of outfall distribution across these river systems.
There is also the potential to re-survey either a full river, or to devise a re-survey process for polluting outfalls, to record the changes in condition of outfalls over time. Options for re-surveying are being considered.
From the current findings it seems that the sewerage system on the River Leven, with no Wastewater Treatment Works on the river until the very downstream end, leads to lower pollution levels overall, compared to those found on the Almond or Esk, where there are multiple WWTWs along the rivers length. Further comparisons with other rivers in the catchment will allow for greater analysis of the differences in systems.
For more information, please contact R.hughes@forthriverstrust.org
Summary Map
CSO map overlaid with completed Outfall Safari data