River monitoring in Wales: why don’t we know what’s in our rivers?

Darllenwch yr erthygl hon yn Gymraeg (Read this article in Welsh)

 

A Welsh-led project is building the tools to finally answer the question and the results are already changing how we manage our land and waterways.

For all the attention river pollution has received in recent years, the headlines, the public outrage, the political pressure, there is a quieter and less comfortable truth underneath it all. We still don’t understand it very well.

Not for lack of concern. Regulations exist. Monitoring programmes exist. But river monitoring across Wales and the wider UK remains fragmentary, and the data that would allow us to say with confidence what is in any given river, at any given moment, and where it is coming from, simply does not exist in any meaningful form for most British rivers. .

The scale of the problem is striking. In Wales, only 40% of rivers currently meet good ecological status under Water Framework Directive classifications, according to Natural Resources Wales. In England, the figure is even lower: the Environment Agency’s 2022 State of the Water Environment report found that just 16% of water bodies achieve good ecological status. Yet despite this, the monitoring infrastructure underpinning those assessments remains sparse. Most water quality sampling in the UK takes place through periodic manual visits, typically a handful of times per year at best. Between those visits, what happens in a river stays largely unrecorded.

The gap is not a political failure. It is a practical one. Existing water quality sensors are expensive, technically demanding to install and maintain, and almost entirely dependent on cellular connectivity to transmit their readings. That is a critical problem in Wales, where many of the rivers under the most pressure run through deep, remote valleys with no cellular signal at all. And so monitoring has remained fragmentary: a handful of well-resourced sites with reasonable data, and long stretches of river observed sporadically, or in some locations, not at all for decades.

When pollution events occur between those visits, they happen invisibly. The evidence moves downstream. The record shows nothing.

A different kind of sensor

That is the problem Lacuna Space, Aberystwyth University, and the UK Agritech Centre set out to solve. Not by campaigning about river pollution, but by building the tools that make continuous, affordable monitoring genuinely practical for the first time.

The project, called STREAMS (Space Tech for River Environments & Agricultural Monitoring Sensors) an Innovate UK-funded collaboration, has two core ambitions. The first is to develop a new multi-parameter water quality sensor: more affordable than what is currently available, rugged enough to survive floods and debris in a working Welsh river, discreet enough to reduce the risk of vandalism, and straightforward enough that local teams can install and maintain it without specialist contractors. The sensor measures six parameters continuously: dissolved oxygen, pH, temperature, electrical conductivity, nitrate levels, and flow. Together these give a detailed, real-time picture of what is happening in the water at any given moment.

The second ambition is connectivity. Most remote monitoring projects have foundered on this problem. Without a cellular signal, the data stays in the device. Lacuna Space’s satellite technology changes that. Using a low-power LoRa transmission protocol, sensors send their readings to a satellite transmitter, which uplinks to Lacuna’s own satellite constellation. The satellites pass overhead, collect stored readings, and forward them to a cloud dashboard where they can be visualised and acted on. As long as there is some view of the sky, the data gets through, from the deepest valley, the most inaccessible stretch of riverbank.

The result is hourly water quality readings from rivers that have never been continuously monitored before. Data arrives at the dashboard within approximately 12 hours of measurement. By morning, you can see what a river was doing overnight.

That is not an incremental improvement on existing monitoring. It is a different category of understanding entirely.

What becomes visible

The hours after rainfall are when the story of a river catchment is most clearly told. For a farmer who has invested in precision fertiliser application, cover cropping, or buffer strips along field margins, those hours are also the moment when the benefits of that investment show up most directly in the data. A rainfall event passes. The expected nutrient spike does not occur. That is not an abstract claim about good practice. It is a measurable outcome, recorded and verifiable, that demonstrates the real difference sustainable land management is making to the river downstream.

That kind of evidence matters for reasons well beyond any individual farm. Land use reform and improved farming practices are reducing nutrient pollution across Welsh catchments, but until now there has been no way to see that progress in real time or attribute it with confidence. Continuous monitoring makes it visible. It also makes it possible to separate the contribution of good farming from other sources in the system, whether a combined sewer overflow, a discharge from water infrastructure, or runoff from land under different management. Patterns emerge across seasons and weather events. When levels shift at one sensor but not at another upstream, the data begins to tell you where a load is actually coming from. That changes conversations between farmers and the people who represent them, between landowners and regulators, and between councils and the bodies responsible for water quality.

It also enables something increasingly in demand: the validation of environmental interventions. Nutrient credit schemes and biodiversity net gain assessments both depend on demonstrating that an intervention actually worked. That requires continuous, calibrated baseline data before, during, and after the work. STREAMS provides exactly that infrastructure.

 

Built here, by people who know these rivers

There is something else worth understanding about how STREAMS has been developed. Not as a footnote, but as a deliberate design decision with long-term consequences.

The sensor engineering, the field deployment, the laboratory calibration and validation of readings, the data science, the dashboard: all of it is being done by people based in Welsh institutions. Researchers and technicians from Aberystwyth University are in the rivers, collecting samples and validating sensor data in the lab. Local engineers are building and maintaining the hardware in the field. When something needs attention at a monitoring site, the response is measured in minutes, not the days it would take a specialist contractor to travel from elsewhere.

The UK Agritech Centre, the third partner in the STREAMS consortium, plays a different but equally important role: ensuring that what the project learnings reach the farmers, land managers, and rural businesses who stand to benefit most from it. River monitoring data is only as useful as the decisions it informs. UK ATC’s networks into the farming and agritech community mean that STREAMS is not just building sensors. It is building the connections between data and the people on the ground who can act on it.

That proximity matters beyond logistics. It means the expertise in how to monitor Welsh rivers, interpret what the data shows, and translate it into practical action is accumulating in Wales, in the universities, councils, and organisations that will be responsible for these rivers long after any single project has ended. The skills being developed span environmental sensor engineering, satellite IoT connectivity, hydrology and water quality science, and data visualisation. These are the foundations of a genuinely capable, locally rooted environmental monitoring sector.

Two Welsh councils have already adopted STREAMS: Ceredigion, deploying sensors along the River Teifi, and Carmarthenshire, now building out a network on the River Tywi. The system has grown from six devices to sixteen. More councils, across Wales and in time across the wider UK, are in active conversation.

River monitoring across Wales and beyond 

The challenges driving this project are not unique to Wales. The same combination of agricultural pressure, ageing sewage infrastructure, and inadequate baseline monitoring data exists across England, Scotland, and beyond. The rivers of the Severn catchment, the Dee, the uplands of northern England all face versions of the same problem that Welsh rivers face today.

Wales is building the tools and the expertise to address that. The ambition, from the beginning, has been to use Welsh rivers and Welsh institutions as the proving ground for an approach that can scale across the UK and, eventually, internationally.

We will be at the Royal Welsh Show from 20 to 23 July, presenting the STREAMS project at a talk on Tuesday 21 July at ABERYSTWYTH UNIVERSITY PAVILION Stand 584-G . If you would like to hear more about what the data is showing and what a national river monitoring network could look like, come and find us. sign up here

Lacuna Space is here to help you scale.

• Explore our Solutions
• Contact Us