"We have the additional problem," he says, "of sewage being released from eight sewage outlets and the river is being polluted by sewage which is being released straight into the silt. This is environmentally bad, but we also want to know what's the public health risk?
"We've been campaigning for a number of years on this and we've got nowhere. We want Scottish Government to put legislation in place to make the environmental bodies test the water for what might be a risk to the public?
I've interviewed Jarvie and other members of the campaigning group SOS Leith several times over the years and followed their battle for testing of water and upgrading of sewage overflows on the silted basins of the Water of Leith.
This is my local stretch of river, a waterway which Jarvie describes as "an open sewer".
SOS Leith's is one of three key cases around sewage pollution which are at the heart of a new campaign by Environmental Rights Centre Scotland which has analysed what is going wrong with Scotland's sewage pollution prevention, monitoring and enforcement, and come up with manifesto calls for political parties ahead of Scottish parliament elections next year.
Along the way they did their own informal testing and found, says Jarvie, "there are definitely pathogens in the water - we know there is literally crap out there."
SOS Leith has a list of ways in which it feels it has been dismissed. Jarvie goes through them. "Despite showing evidence of faecal contamination in water and silt samples from the river, SEPA repeatedly dismisses our complaints. SEPA's oversight body, Environmental Standards Scotland (ESS), has upheld SEPA's dismissal. Scottish Government has failed to act. And, meanwhile, Scottish Water, responsible for sewage pollution management, has evaded responsibility."
But, working with ERCS, who gave them from legal advice, has, he says, been a revelation. "Because they know the law they were able to guide us through freedom of information requests, help us understand what the responses were, where we could take things to next." "They got us to the point of understanding why nothing was happening, and that our little campaign, on its own can't have any real impact."
Leith resident and campaigner Jim Jarvie at Rennie's Isle where waste has built up. Photo Gordon Terris
The chief reason for this lack of progress, Jarvie says, is that "the legislation is not there - it's not there, for instance, to make SEPA test for sewage pathogens".
"The ERCS got us to the point that we understand that the problem is that Scottish Government isn't passing legislation to find out what the risks are. They're not passing legislation to make polluters pay, and they're not passing legislation to invest in solutions."
He gives as example, the handling of a situation where a sewer overflow was releasing swage near Great Junction Street Bridge, a CSO was releasing sewage, and residents complained to SEPA. The complaint then got taken by ERCS to Environmental Standards Scotland.
"But all ESS did was to check with SEPA. They didn't challenge them. We also don't see SEPA challenging Scottish Government to say, 'Help us regulate better. Give us legislation to mandate we test for sewage.' They have their rules, and they're just sitting with those rules."
Jarvie has little interest in comparisons between England and Scotland. "Often we hear these comparisons - that Scotland's better than England, because England's all privatised - but the problems are here as well. But then the Scottish Government obfuscates by saying, well, 66% of Scottish water is in good ecological condition. That's like saying, 'You've got head trauma - don't worry about it because the rest of you is okay.' The real pollution right across the central belt is not being addressed. "
The Independent Water Commission found that 66% of Scottish waterways are in good ecological condition, compared with 16.1% in England and 29.9% in Wales.
But, Jarvie observes, "I would say that using the indicators of sewage in the water at bathing waters places, the issue, and the symptoms are the same. The background governance issues might have variants, but the bottom line is, government in England isn't doing enough to force private water companies to change behavior. And up here, the government could do that because Scottish water's public."
Part of the problem at the Water of Leith, and more widely, Jarvie says, is what we don't know. "Remember how Donald Trump during Covid said if we don't test there wouldn't be so many cases. If you don't test the water you don't find the pathogens.
"We don't know what the threat to the public is. Sewage pathogens in the water are meant, in theory, to be flushed out to sea, but in Leith they're getting trapped in the silt. So after 60 years of silt accumulation, what's in there?
"We know that we can smell the sewage that comes out by the King's Wark. You can see the sewage outlets, which are above the silt, leaking out into the water, even sometimes in dry weather.
"Is it okay that the water of Leith down here is a running sewer? People do interact with the water. People fish. They occasionally kayak. There are people working on the boats, people dangling their legs over under water. If you got to Coalie Park, where they've got the steps going down to the water, people are using it, children are feeding the birds there. And in any case, who's happy living by something which is contaminated?"
Despite their campaigning for upgrades of the combined sewage overflows, eight of which release into the river basins, they have, he says, seen "none". He also points out that, though CSOs are designed only to release during periods of heavy rain, as a mechanism to prevent backing up into homes, there have been occasions when they have released during dry periods, according to Royal Botanic Gardens data, and that this would be "illegal".
Jarvie worked for many years in Bangkok, on the Asian Cities Climate Resilience Network . "The big lesson there," he says," which applies here, is that the technical stuff isn't difficult. You can always find an engineering solution to a problem, the problems governance, which is exactly the issue here."
A Scottish Water spokesperson said: "The main drivers for the investment in the Water of Leith are what SEPA call 'aesthetic'. So this is about upgrading CSOs by installing screens to help remove sewer related debris from the river, rather than Scottish Water's investment being driven by water quality concerns.
"In terms of investment, Scottish Water is making good progress on the Water of Leith where we are taking a systematic approach to investment to improve the impact of overflows on the whole river. Working south to north, following the river, we upgraded 10 overflows in previous investment periods in the upper reaches of the river, we are on site in Corstorphine and Balgreen at the moment, and we have upgrades at other sites due to start in 2026, including Gorgie Road and Crammond."
The Water of Leith at Rennie's Isle
For SOS Leith it has been a long battle. "We worked very hard in it for the first two or three years, and then it really slowed down as we came to the moment of realising that we can't get anywhere till legislation changes. What's interesting is that was the same with the River Almond Action Group. I think what's exciting about the ERCs work is that they're helping unite different campaign groups together for a voice, underneath their knowledge of the legal framework, to push for action."
Dr Pippa Scott of River Almond Action Group, which has also had help and advice from ERCS, echoes this sentiment. RAAG was formed in response to concerns over significant sewage pollution in the River Almond downstream of sewage works and has been fighting for over five years now.
I remember first walking that stretch of the Almond in 2021, with Alison Baker, then director of Forth Rivers Trust, and observing baby wipes clinging to the spindles of overhanging twigs downstream from an outfall pipe. On another occasion, a RAAG member who pointed out where, as a teenager, he would swim as a teenager, jumping off the rocks into the deep pool below.
The group sought bathing waters status, as a way of getting monitoring and improvements, but were refused the designation on grounds that the site wasn't used by the minimum of 150 bathers. They turned to ERCS who ultimately made a representation to Environmental Standards Scotland, arguing that the minimum bather count of 150 was unlawful.
Dr Scott says: "It is exhausting to think that five years ago, when community members around the River Almond raised concerns about the frequency of sewage overflows and pollution entering our local waters, we were told there was nothing to worry about and that "the system was operating as it should".
"Last year, the Environmental Standards Scotland report effectively confirmed that our concerns were valid all along. Communities are standing in as stewards of the river but in reality this needs the government to take action. Change on the ground is now well overdue."