Extended Riverfly with the Don Catchment Rivers Trust River Went Project

The usual hazard I encounter getting to river volunteer event days is sleeping through my alarm clock. This Friday I had a legitimate extra hour in bed courtesy of the Don Catchment Rivers Trust, who had organised an event close to me. However, my pleasant walk to the site, a favourite walk for me, was held up by a large cow making strategic use of a necessary gate as a scratching post. I tried five minutes of gentle cajoling, before deciding to risk being crushed and squeezing past.

The event was an introduction to Riverfly Extended Sampling. The site chosen, championed by Hiram and Jason, was the intriguing location of before and after run-off from the A1. There is an iconic viaduct, built in the 1960s, which brings a gentle roar to the valley, which houses attractive villages and the beautiful unspoiled Brockadale woodland. Also in attendance were Sally and Rebecca from DCRT, Dave and Sue who river monitor locally, and the ‘Knowledge Man,’ who was indispensable over the course of the day, Sheffield-based Paul. Throughout the day Paul frequently identified several species at once, and wryly commented to me when I announced that I thought I had a tray, “with nothing in it,” that “there’s a sleeve in it.” As with all of his pronouncements over the day, this was duly proven to be correct.

My walk to the event, much more direct than the route by car, followed the river Went the whole way. Whilst I have a sentimental attachment to this river, my dad having played in it in the sixties, and some of the locations are beautiful, let’s not pretend it’s teeming with life to the fullest extent. I walked past the large sewage treatment centre a mile and a half upstream of the sampling site, which discharges so frequently that it is rumoured phosphates are going to be removed first in a facility upgrade.

Why is an extended riverfly necessary? It runs alongside the regular ARMI count and is cross-compatible, although the stone search is slightly shorter, replaced by a surface sweep. It is designed to give a more detailed picture of the character of a river. After numbers are inputted into a bespoke spreadsheet, the output is a Water Quality score and a Silt and Flow score. It is a new scheme, developed from two pilot schemes in Dorset and Lincolnshire. Unlike the regular riverfly, there are not currently trigger levels. Typically, this type of survey would be completed two to four times a year.

When I arrived, three tables were set up in the shelter of the viaduct, one laden with coffee and treats, one set up with traditional “party food” trays placed on laminated A2 labelled sheets, and the third with a more compact and orderly labelled trays with compartments of the type you might keep beads or nuts and bolts in, with some leaflets and books. I’m afraid I didn’t refer much to the printed matter, preferring instead to defer to Paul and Sally’s knowledge. There were also sturdy long-lived Soviet-era microscopes inherited from the University of Sheffield, which revealed surprising details and colour in our invertebrates, an ample supply of plastic spoons (for sorting insects, although Dave and Sue came armed with long-handled paint-brushes, a tip new to me), and small-handheld lenses, in addition to a fair amount of river-water confidently dispensed by Sally at one point as she tried to pour some of the sample through a tiny net.

After an explanation of the survey we proceeded to our first sample. The underlays to the trays were beautifully designed. Sally had done an amazing job using colour and type of species to delineate them. We gravitated towards the table with the octagonal trays for the most part. I did make a token effort to use the bead-box system, but for me at least the larger layout was far more intuitive and educational. In practice the more compact version is probably far more viable in the field, but for accessibility, ease and enjoyment I’d plump for the space-consuming way.

Our first sample had everything from bivalves to olives, and plenty of them. We spent about 90 minutes sorting through the weeds, leaves and vegetation, rescuing the occasional fish, then completed the first survey form. The form is straightforward and is cleverly designed to make obtaining the standard ARMI numbers very clear.

 I didn’t find it intimidating or overwhelming. For some reason I was able to spot incredibly tiny invertebrates comfortably – I often struggle with doing things involving very fine motor control such as embroidery, but in the context of shuffling little invertebrates around outdoors with other people this was fine. Many of the additional species were immediately obvious, such as leeches and hoglice, and those that weren’t became more familiar over the day, such as blackfly larvae. I remain incompetent at distinguishing blue-winged olives from regular olives, as of the several species of mayfly covered only olives had received the invitation.

After a delicious lunch thoughtfully provided by Hiram from legendary local bakery Hinitts, I helped Sally as timing buddy and spotter for the second location downstream. My favourite spot in Brockadale is the wall of Hart’s Tongue fern, and our second sampling location was right there, approached from the south bank after squeezing through a gate. I’m not sure how Sally got the bucket through, I was too busy wiggling and hoping I wouldn’t get stuck. There were significantly less reeds at the second location, but we made do, Sally performing the surface skimming which is added to this sampling type with confidence. With the light and people’s energy fading, we analysed the second sample, which was less abundant, particularly in gammarus, but very rich on minute bivalves, which were challenging to count.

The day was extremely well-organised and we were lucky with the weather. As for the sampling itself, obtaining the sample is mostly the same, and analysing it is not too taxing. I’m still at the happy to be able to identify a cased caddis stage, never mind whether they have hoods, bush-tails, or weighted cases, but I will know to look more closely the next time I see one.

If you have tried the standard riverfly and not enjoyed it, Extended probably won’t change your mind, but I would recommend trying out Extended to anyone who does river sampling, to bring a little more context to regular sampling. The final scores were Site 1, an ARMI score of 7, Water Quality 28, and Silt and Flow 32, Site 2, ARMI score of 5, Water Quality 21, and Silt and Flow 26.

I’m disappointed that the River Went, through unspoiled woodland, couldn’t muster better ARMI scores than I get with monitoring with the Calder and Colne Rivers Trust, on my blue-tinged stretch of Spen Beck. I guess that’s what you get when you channel run-off from a dual carriageway into a watercourse, which is itself already essentially an outfall for a large village by the time it reaches Wentbridge. Sally and Paul were optimistic that the phosphates measure will improve matters.

Please contact Sam Riley-Gunn at contact@aireriverstrust.org.uk if you are interested in monitoring with the Aire Rivers Trust next season, or if you would like to hear more about other river-related events.

Sally of DCRT can be contacted at info@dcrt.org.uk or www.dcrt.org.uk if you are in the catchment area for the River Don and would like to know more about standard or extended riverfly or practical days.