European benchmarking: origins, purpose and outputs by Paul Raven

It was quite obvious early on in the development of RHS, and confirmed by results from the first baseline survey during 1994-97, that the UK had insufficient near-natural river channels to provide a reasonable calibration of habitat quality assessment. The ‘top quality’ benchmark sites surveyed in the UK simply didn’t do the job to cover the range of river types. So we looked to continental Europe, not only for near-natural examples, but also to see if RHS worked there. We also wanted to RHS on as wide a range of rivers as possible as part of development of the CEN guidance standard for assessing the hydromorphological character of rivers (Boon et al., 2010). It was colleagues on the CEN working group that provided the initial network of contacts.

The first phase involved comparison of different methods for assessing river morphology that were either already in use, or being developed across Europe. A very informative meeting to compare ideas and demonstrate techniques on the nearby river was held in Galloway, SW Scotland in 1998. It became apparent that even though the various methods all made use of similar river features and artificial modification categories, there was considerable variation in the ways these were recorded and how the information was used to evaluate channel form and habitat quality.

For RHS development, there were valuable lessons to be learnt by testing it across different bio-geographical regions, hydrological conditions and land-use patterns. From a UK perspective, the RHS method appeared to be sound, but if it was to be used elsewhere, specific testing would be needed and adaptations recommended in the light of experience. It was a great advantage that RHS was being used for the STAR project, involving several different European countries (Furse et al., 2006). Also, that a southern European version of RHS was being developed, specifically adapted for Mediterranean rivers (Buffagni & Kemp, 2002).

The second phase involved a specific comparison between RHS, the German LAWA method and the then French method SEQ. Rivers in France and the Pyrenees were surveyed by Patrick Charrier using all three methods. The work highlighted similarities and differences in approach, ease of use, analysis and conclusions. The conclusions and recommendations were discussed by the CEN workgroup in 2001 and published in 2002 (Raven et al., 2002).

The third phase involved the long overdue review and updating the 1997 RHS survey form. We took the opportunity to test it and testing it on rivers during our second visit to Finland, in June 2002, including streams inside the Arctic Circle. It was here that two mantras, relevant to all subsequent benchmarking surveys emerged: “always expect the unexpected”; and “never underestimate the importance of local knowledge”. We had encountered something unfamiliar to us in the UK; the forestry practice of removing boulders from the river channel so that felled tree trucks could be floated downstream to sawmills.

The 2002 Finland visit and further discussions with CEN working group colleagues triggered  the fourth phase: a programme of benchmarking trips to various countries. So far these have covered eastern Poland (2003, 2007),  Slovenia (2005), Southern Bavaria and Austria (2006), South-East France (2007), the Picos Mountains in Northern Spain (2008), Southern Portugal (2009), the Drawa River, Poland (2008, 2009) and the High Tatra mountains of Poland and Slovakia (2010). Each of these visits was written up in an illustrated report which contained summary results. Pdf versions of all these reports can be found on this website (click here). The results and broad conclusions were also published in Aquatic Conservation (Raven et al., 2010). The results from our most recent visit, to eastern Slovakia, are now being written up now. Each report has an Appendix with a series of recommendations for RHS generally and in particular for carrying out surveys on rivers in the study area

The benefits of these benchmarking surveys have been immense. We have established contact with those involved in similar work for the Water Framework Directive and river conservation right across Europe. We have had direct experience of carrying out surveys with host colleagues and being able to explain reasons for RHS and how it can be adapted and improved for use elsewhere. We have accumulated masses of new information about different rivers and how they have been affected by historical land-use change.

Through this website we will in due course be able to share RHS data on all our benchmark surveys, enabling users across Europe to see what was done, problems encountered and recommendations made. The recommendations be collated and a discussion group established to help improve survey technique and confidence in recognising unusual features in particular. We hope this leads to improved design and use of RHS and its integration with other survey work for river management and conservation purposes as well as well as academic research. This resource will consolidate progress made over the past 10-15 years and inspire others to take a broader outlook on river assessment.



Boon PJ, Holmes NTH, Raven PJ. 2010. Developing Standard Approaches for Recording and Assessing River Hydromorphology: The Role of the European Committee for Standardization (CEN). Aquatic Conservation:Marine and Freshwater Ecosystems 20: S55-S61.

Buffagni A, Kemp JL. 2002. Looking beyond the shores of the United Kingdom: addenda for the application of River Hbaitat Survey in South-European rivers. Journal of Limnology 61: 199-214.

FurseMT, Hering D, Brabec K, Buffagni A, Sandin L, Verdonschot PFM (eds.) 2006. The ecological status of European rivers: evaluation and intercalibration of assessment methods. Hydrobiologia 566: 1-555.

Raven PJ, Holmes NTH, Charrier P, Dawson FH, Naura M, Boon PJ. 2002. Towards a Harmonized Assessment of Rivers in Europe: a Qualitative Comparison of Three Survey Methods. Aquatic Conservation:Marine and Freshwater Ecosystems 12: 405-424.

Raven PJ, Holmes NTH, Vaughan IP, Dawson FH, Scarlett P. 2010. Benchmarking Habitat Quality: ObservationsUsingRiver habitat Survey on Near-Natural Streams and Rivers in Northern and Western Europe. Aquatic Conservation:Marine and Freshwater Ecosystems 20: S13-S30.