The Big River Watch: Monitoring Your Local River
- Luke Farnish
- 19 hours ago
- 4 min read
The Big River Watch is back! You can take part from the from the 25th of April to the 1st May. In this blog post, we talk a little about how you can get involved, what other citizen science projects are out there and the experiences of the ESRT's Project Support Officer, Luke Farnish, as he gets his boots muddy in the name of citizen science.
The Big River Watch: What is it and how can you join in?
Twice a year, The Rivers Trust run a Big River Watch and the next one takes place from 25th April to 1st May.
Anyone can take part in these week-long citizen science surveys that help to build an important picture of river health across the UK and Ireland.
How to take part:
Step 1: Download the app
Download the free Big River Watch mobile app before visiting your chosen river.
Step 2: Complete the survey by your river
Pick a riverside spot, spend 15 minutes watching the river, and answer the questions in the survey. You can complete the Big River Watch at your favourite local spot, or get to know somewhere new. The survey will ask you about what you see, from wildlife and plants to any signs of pollution. The in-app pollution and wildlife guides can help if you're not sure what you're looking at.
Step 3: Upload your survey
Press submit, and upload your Big River Watch survey!
Step 4: [Optional extra] Complete a Great UK WaterBlitz
New for 2025, if you've signed up for your kit in advance, you can also test the water and monitor nitrate and phosphate levels.
Then river specialists will analyze the results.
The app and survey are open year-round, so you can keep recording useful information about your local river at any time, if you wish.
Share your experience and your photos on social media using #BigRiverWatch.
For more information on how to join in and to explore the data as it flows in, see the Rivers Trust Website
Want to join in year round with other citizen science projects?
The Big River Watch is an excellent way to get involved in collecting data about your local river, but surveys only occur twice per year. For those interested in performing more surveys on their local river, here are some further ideas on how to get involved.
Suffolk
The Deben Climate Centre perform citizen science water quality monitoring of the River Deben and are expanding to cover additional rivers.
Essex
The Essex Rivers Hub has a citizen science programme called the Essex RiverWatch administered by the ESRT, open to groups and pairs of interested people. Note that this is also available in south Suffolk for those in the catchment of the River Stour and its tributaries.
Essex Wildlife Trust offer a programme called River Champions for those able to spend a bit more time monitoring rivers and volunteering more generally.
National
Running concurrently to the Big River Watch is the Earth Watch Great UK Water Blitz programme. For April 2025 they distributed 6500 water testing kits across the UK which were all requested over a month before testing began. If you want to be involved next time you will need to get in quickly!
For established groups looking to get more involved in monitoring, River Fly testing is a great option. This involves sampling the invertebrates found in your local river.
Monitoring the River Box
With so much on this weekend, I wanted to visit one of our Essex RiverWatch groups to see how they were getting on. Natural Boxford who measure the River Box and its tributaries around Boxford, Suffolk kindly allowed me to join them for a few hours.
With four measuring points to perform four separate projects at (Essex RiverWatch, Big River Watch, River Fly monitoring and Earthwatch's Water Blitz), we split into two groups. The group I was with headed off to test a tributary of the Box which winds through houses and garages. Testing using either the Water Blitz or Essex RiverWatch methods produced the same results (thankfully of relatively low levels) for nitrate and phosphate).
We became somewhat distracted, though, by another of our river's issues; invasive species. A large patch of Himalayan balsam was growing right where we sampled and so we spent some time clearing this. Just after we were done, a resident spoke with us about his concerns for the stream flooding. It's always good to hear local resident's thoughts when out and about. Fortunately, a council meeting was due the next day and one of Natural Boxford's volunteers promised to speak on the man's behalf.
We visited our second site which was downstream on the main River Box by a ford. The water quality here was equally as good. With that done we returned to base camp (one of the volunteer's homes) for a quick coffee and bit of cake (essential kit). The volunteers then began collecting aquatic invertebrates to analyse for river fly monitoring. Sadly though, the balsam had taken a long time to pull and I had to leave after just a few minutes of looking at all the species pulled from the river.
Perhaps even more interesting than our water testing though was to speak with the group. It is clear that everyone gains a great deal from doing citizen science. Time together, a greater understanding of the river and how it changes and the feeling of being part of something larger that can contribute to collective understanding and action.
I would like to thank not only everyone Natural Boxford for allowing me to join them for the day, but to all participants of all the citizen science projects happening this weekend. I hope you all have a good, safe time collecting your data. If you aren't involved and think this sounds like something that would interest you or a group you are in, follow the links above for more information.
Get Involved
Download The Big River Watch app for IOS on the Apple App store
Download The Big River Watch app for Android on the Play store
Find out more about the Big River Watch
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