About Marc Naura

RHS trainer and developer

NEW – RHS Toolbox 1.5 with RHAT WFD assessment and import from RAPID database

The RHS Toolbox 1.5 features new functionality to perform a RHAT assessment and to import data from the RAPID database.

The software is on a free trial for 30 days and it is available for 32 and 64 bit version of Office.

New features:

River Hydromorphology Assessment Technique (RHAT) scoring form

The River Hydromorphology Assessment Technique (RHAT) was developed in Northern Ireland by the Department of Environment to assess the hydromorphological condition of rivers for the Water Framework Directive (WFD). The field survey methodology was based on RHS and contains the same amount of information as a standard survey. The main differences are the width of spot-checks, which in RHAT are 50 m wide. The RHAT survey methodology also allows for partial surveys of the stream as the final scoring system does not rely on recorded data for its implementation.

The field assessment of morphological condition as part of RHAT is carried out in the field using expert opinion. Eight attributes representing bank and channel features and geomorphological functions are assessed on the scale of 0 (bad) to 4 (high) for their condition. Guidance on assessing condition is provided in the RHAT manual.

As the RHAT condition assessment is not calculated directly from survey data, it is possible to derive the score for a standard RHS. The RHAT condition assessment sheet was therefore added to the RHS toolbox as an additional option whilst doing surveys

RHAT assessment form in the RHS Toolbox

RAPID data import

RAPID is an application developed by the Centre for Ecology and Hydrology in the United Kingdom to input and process RHS data.

You can now import data from the RAPID database version 2 and 3 using the import button.

RAPID import menu in the RHS Toolbox

For more information about the software, you can go to the software page or read the manual online.

Instructions to download and install the RHS Toolbox:
1- Download the zip file for the relevant version of the RHS Toolbox: 

.
2- Create a RHS folder somewhere on your computer (e.g. C drive) and extract the content of the zip file into that folder.
3- If you do not have Access 2010 or later already installed on your PC, you can download and install the free Access 2016 runtime here
4- Double-click the file RHSDataInput.accdr.

The RHS Toolbox development requires investment in time and resources so it is unfortunately not possible to deliver it free of charge. You have access to a trial version for 30 days after which you will have to register and purchase a license. During the trial period, every time you log in, you will be asked whether you wish to purchase a license and register. Information on pricing can be found here

Potential issues: the RHS Toolbox was tested on UK (English) Windows Operating Systems. Due to different ways of representing decimal points, some of its functionality may not work on French and other Operating Systems that use commas (,) instead of points (.) to represent the decimal fraction of real numbers. Please let us know if you come across such problems.

Online (and virtual) training on hydromorphology

Last week was a bit of a first for us and myself. We (the River Restoration Centre) held our first full day online hydromorphological training course with a virtual field work component!
Due to the Covid-19 outbreak, we have been unable to offer our usual series of training courses in person. The challenge here was to develop a course that provide the same kind of experience as the one we normally run that includes a very important field component where participants can directly experience hydromorphological processes and forms as well as pressures and impacts of modifications.


So we have been busy designing new ways of offering the same experience online by adding virtual site visits and even fieldwork. We delivered the Introduction to Hydromorphology (Level 1) training course using a combination of Zoom and Google Earth software. Fifteen delegates joined us on the Zoom call with regular switches to Google Earth and Streetview to demonstrate and experience hydromorphological processes forms and drivers virtually using one of our case study catchment on which we collected a lot of 360 photographs. Polls were set up to ask the delegates questions, and create as much of an interactive session as possible to keep everybody’s attention alive.

The crux of the course was to introduce delegates to a framework for analysing catchment and river processes, forms and how they are influenced by modifications and land management. This was achieved through formal short presentation followed by group work, in pairs, in the air and on virtual ground using Google Earth online, 360⁰ photos, and historic maps.

Delegates worked in pairs through tasks to spot features and modifications, think about processes, and map pressures. Finally, delegates were asked to assess everything we had gone over in the training and offer justified restoration options. This was a great opportunity to go over all the concepts we had been introduced to, and brainstorm ideas.

Feedback from the course has been really encouraging, and we are now looking at adapting the rest of our courses online and run more this Summer and Autumn. We are also considering adapting the River Habitat Survey course, potentially turning the existing presentations that are delivered in a training room into a series of online modules with virtual field work, and organising site visits separately over a few days to practice doing the survey whilst maintaining social distancing rules. We will be in touch with more information soon and we would welcome your suggestions.

In the meantime, please visit the RRC website to view our training events and please email us rrc@therrc.co.uk if you are interested in attending a virtual training course.

NEW – RHS Toolbox 1.4 with automated derivation of GIS data and new quality indices

The RHS Toolbox 1.4 features new functionality to extract map data such as altitude, slope and geology as well as indices on hydromorphological naturalness and fine sediment runoff from agricultural sources. The software also features new indices assessing hydromorphological impact.

The new tools will help practitioners with habitat assessment for the Water Framework Directive, Planning Applications, River Restoration and more. 

The software is on a free trial for 30 days and it is available for 32 and 64 bit version of Office.

New features:

Automated map data extraction for sites in England, Wales and Scotland (only available to licenced users)

To be able to run a context analysis with the RHS Toolbox, you need to derive altitude, slope, distance to source and height of source to calculate the PCA score for your site that will be used to select sites of similar types (see Jeffers, 1998 in References and Context analysis).

Using the RHS Toolbox, you can now automatically extract this information using a database of previously derived point on the river network. A form will display all nearby points using the mid-site grid reference and you will be able to map them to decide which one to choose for your site (see below). This feature is only available to licenced users and is not available to trial versions.

The process will not only extract data on for PCA score calculation but also background information on geology, sinuosity, typology using the Jeffers types (1998) and also predictions for four hydromorphological indices (Indices) in semi-natural conditions. This will enable the calculation of Hydromorphological Impact Ratio indices for your site to assess departure from semi-natural conditions (see below).

New indices

A series of indices and fields have been added to the interface.

Hydromorphological Impact Ratios

Provided your site is located in Great Britain, the software will extract predictions for four hydromorphological indices (Appendix 2 and also in the resource section and Naura et al, 2016) at semi-natural conditions (the ‘expected’ column in the figure below). These indices were derived as part of a research project (Naura et al ms).  The RHS Toolbox will then calculate Hydromorphological Impact Ratios (HIR) for each index.

Hydromorphological Impact Ratios representing the distance to semi-natural condition in % for four hydromorphological indices

HIRs represent the level of departure from semi-natural condition (or impact) for each index compared to the maximum level of departure (or maximum possible impact) that could be expected (see figure below and Appendix 4 or here for download). The HIRs are expressed as percentage values from 0% (no impact) to 100% (maximum possible impact). The site HIR represents the maximum possible impact for any of the four indices categorised into 12.5% impact classes:

  • Very Low : HIRindex between 0 and 12.5%
  • Low : HIRindex between 12.5 and 25%
  • Moderate : HIRindex between 25 and 37.5%
  • High : HIRindex between 37.5 and 50%
  • Very High : HIRindex between 50 and 100%.
Hydromorphological Impact Ratio derivation for the Channel Substrate Index. The ratio represents the relative difference between observed and expected index values compared to the maximum possible impact observable.

Agricultural fine sediment load and potential risk to biota

Provided your site is located in Great Britain, the software will extract information on agricultural fine sediment delivery to your site in tonnes per year and derive a series of indices representing Agricultural Sediment Load (ASL), Fine Sediment Accumulation (FSA) and overall Agricultural Sediment Risk (ASR). These indices were derived as part of research for the UK government and published in 2016 (Naura et al 2016).

Total agricultural fine sediment delivery represent all fine sediments transported from upstream in the water column and local sediment delivery through run-off and tributary inputs. The data are derived using modelling but can be entered by hand by the user.

Local agricultural fine sediment delivery represent all fine sediments delivered through run-off and tributary inputs.

The Fine Sediment Accumulation index is derived directly from your RHS site spot-check data for channel substrate.  Sites will be categorised according to the number of spot-checks with silt, sand or clay as:

  • Very low = 0 spot-checks with fine sediments
  • Low = 1 spot-check with fine sediments
  • Moderate =2,3 spot-checks with fine sediments
  • High = 4 to 6 spot-checks with fine sediments
  • Very high = 7 to 10 spot-checks with fine sediments

The ASR combines the FSA and ASL using the following matrix

For more information about the software, you can go to the software page or read the manual online.

Instructions to download and install the RHS Toolbox:
1- Download the zip file for the relevant version of the RHS Toolbox: 

.
2- Create a RHS folder somewhere on your computer (e.g. C drive) and extract the content of the zip file into that folder.
3- If you do not have Access 2010 or later already installed on your PC, you can download and install the free Access 2016 runtime here
4- Double-click the file RHSDataInput.accdr.

The RHS Toolbox development requires investment in time and resources so it is unfortunately not possible to deliver it free of charge. You have access to a trial version for 30 days after which you will have to register and purchase a license. During the trial period, every time you log in, you will be asked whether you wish to purchase a license and register. Information on pricing can be found here

Potential issues: the RHS Toolbox was tested on UK (English) Windows Operating Systems. Due to different ways of representing decimal points, some of its functionality may not work on French and other Operating Systems that use commas (,) instead of points (.) to represent the decimal fraction of real numbers. Please let us know if you come across such problems.

Using River Habitat Survey in the Geography Curriculum at the University of Worcester

by Professor Ian Maddock, University of Worcester, January 2020

Third year undergraduate students at the University of Worcester can take an optional module in River Conservation and Management as part of their Geography or Physical Geography degrees. We offer a practical-based degree programme with a strong emphasis on fieldwork and in this module, the practical work is focused around the use of RHS. The first half of the module is largely classroom-based, focusing on new approaches to environmentally-sensitive river management, including river restoration, natural flood management and the application of environmental flows.  Guest speakers from the EA, wildlife trusts, rivers trusts, local authorities and environmental consultancies provide an overview of some of the organisations involved with these topics and give students insights into potential careers relevant to their interests.

copyright Ian Maddock

RHS provides the focus for the 2nd half of the module. Students are familiarised with the field survey methods and features that are assessed in the classroom and then get to trial the software in a PC room with dummy data sets. This allows them to get used to data input and score calculation and explore the impact of altering input fields and assessing the effect on the metrics calculated. They get a feel for what influences the Habitat Quality Assessment (HQA) and the Habitat Modification Score (HMS) and their sensitivity to data input.

This is followed by three weeks of fieldwork using RHS. The first one involves a ‘practice’ survey of a local stream and then straight back into the computer room for data input and metric calculations. Students work in small groups (2s and 3s) and all assess the same reach. Comparing scores between groups and identifying which features were scored differently between them enables a discussion on observer variability and the need for training to help standardise approaches and optimise data quality. In the following two weeks students assess two contrasting sites. One is a largely natural gravel-bed stream in a local nature reserve, with minimal direct human impact and high habitat quality. The second is a contrasting, heavily-modified urban stream dominated by channelisation including weirs, bank and bed reinforcements and channel realignment. For their assignment, students are required to produce a mock consultancy report and use the RHS outputs to 1) assess the current habitat quality and habitat modification, and 2) make recommendations for the implementation of suitable river restoration techniques. The important thing with the latter is they use the breakdown of the HQA and HMS metrics to underpin their recommendations, explicitly acknowledging the output of the RHS survey results to justify the techniques proposed.

RHS provides an ideal field technique for this type of work for many reasons. Students can become proficient in its use relatively quickly, survey times are sufficiently short to enable them to conduct a survey in a 3-4 hour timetable slot, it promotes a discussion about how to identify river habitat features, what features are deemed ecologically relevant and how the differing importance of features is acknowledged by the differential weighting of them towards the calculated metrics, and how habitats have been impacted in the past or can be restored. It also enables a more general discussion on the use of rapid visual assessment methods as a survey protocol compared to more detailed but time consuming quantitative techniques. We plan to trial the new mobile app this forthcoming year which should provide a more convenient way of recording data in the field and uploading it to the PC-based software.

Professor Ian Maddock

Professor of River Science

University of Worcester

RRC Senior River Restoration Adviser Job Vacancy

the River Restoration Centre

You want to make a real difference in the field of river restoration and habitat enhancement, working in the UK and Ireland at the interface between practice, science and policy?

The River Restoration Centre (RRC) is seeking a Senior River Restoration Adviser to provide expert advice and guidance, delivery of assessment, planning and scoping projects, the design and delivery of training courses and the coordination of an international conference on river restoration science.
Closing date for receipt of applications is 5th January 2020

For more information, go to the Cranfield University website : https://www.therrc.co.uk/jobs/senior-river-restoration-adviser

Books on rivers and river management

Rivers by Nigel Holmes and Paul Raven
Rivers_book_coverAn attractive new book by Nigel Holmes and Paul Raven should be a ‘must-read’ item for those with a professional, academic or general interest in rivers. Entitled simply ‘Rivers’ it is number 3 in the British Wildlife Collection series, and has 432 pages packed with more than 300 colour photographs, plus charts, graphs and other images. The sub-tilted theme is ‘a natural and not-so-natural history’ and the book describes how British rivers and associated plants, invertebrates, fish, birds and mammals have been changed by Nature and mankind since the last ice age.

It describes how and why these changes have occurred and explains how subtle variations in climate, geology and human history in different parts of Britain, have made each river unique. Three rivers, the Hampshire Meon, Welsh/Cheshire Dee and Endrick in Scotland are used to demonstrate how in more detail. The overall message is that understanding how rivers behave is crucial if they are to be properly managed and conserved for the benefit of people and wildlife into the future.
Copies can be ordered from British Wildlife Publishing (£30, free P&P within the UK) – details can be found here – and orders for signed copies taken by phoning 01865 811316.

Decision Support Systems: factors affecting their design and implementation within organisations. Lessons from two case studies by Marc Naura

DSS_book_Cover

How do we ensure that scientific tools, techniques and outputs (e.g. models, software, analytical techniques) are used in the ‘applied’ world’ of industry and government? In this research, we take the example of a group of software called Decision Support Systems (DSS) to discuss, with the help of literature reviews and 2 case studies, the factors affecting their implementation success within organisations. We particularly concentrate on the study of their interaction with organisational culture and the ‘frictions’ that assumptions taken in their design may generate with existing work practice and organisational beliefs. We further propose a methodology for developing models and tools that accounts for organisational and cultural factors, and demonstrate its application on a case study in a major public environmental organisation in the United Kingdom.

The book takes, as an example, the development of ToolHab, a Decision Support System for managing river habitats within the Environment Agency, England and Wales. ToolHab was originally designed for prioritising sites for habitat enhancement work for fish and it is now being tested for other purposes, such as the delivery of a environmental targets under the EU Water Framework Directive. The case studies illustrate the practical and cultural hurdles researchers, software designers and scientists face when attempting to develop methods, techniques and tools for practitioners and what can be done about it. The literature reviewed shows that these issues are by no means restricted to the environmental sector alone but are widespread across public and private industries whether in medicine, marketing or sales. Thus, the approach suggested will be relevant to many scientist, engineers and software developers involved in the production of tools and techniques across a wide spectrum of organisations (link to website).

Site selection strategies and tools for river surveys

by Naura, M. & Hornby D. D.

Choosing a sampling strategy

How do you choose survey sites for river characterisation?

In short, it all depends on your overall aims.

The sites chosen for the River Habitat Survey (RHS) baseline surveys in 1994-6 and 2007-8 were originally identified from Ordnance Survey1:50,000 Landranger maps using a stratified sampling strategy using a 10km grid.  The aim was to get a representative picture of river habitats across England and Wales.  The stratification was introduced to provide a sample that could also be used to characterise smaller geographical units such as river basins or catchments.  Random sampling strategies without stratification may indeed produce clusters of sites in parts of the country and leave some areas unsampled. In the end, 3 RHS site locations were randomly selected within every 10km-square in England, Wales and Scotland.

Stratification can be performed according to a geographical area (e.g. squares or catchment boundaries), a river type or stream orders.  It all depends on your specific reasons for introducing a stratum in your sample.  If your aim is to compare the distribution of features across river types, you may want to stratify according to a set typology or stream orders. If your aim is to compare counties or states, then state or county boundaries may be used to stratify your sample.

You need to remember that you need to account for the effect of stratifying your sample when analysing the data.  For example, a geographical stratification using squares (e.g RHS baseline surveys) may introduce a bias when analysing the overall sample as a whole as it gives more weight to squares with low stream densities.  If, following survey, you find that 80% of your sites are heavily modified, it could be wrong to state that 80% of rivers in your geographical area are modified because unmodified streams in upland and headwaters squares will be under-represented compared to modified streams in lowland squares.  You would need to correct your statistics using stream densities for each square.

There are other methods for sampling.  One is to select sites at regular intervals (e.g. every 2km along the network from source to sea).  Regular samples generate unbiased statistics as long as the chosen sampling interval does not correspond to the ‘wave length’ of the features you want to record.  For example, the distribution of features such as riffles is a function of channel bankfull width.  Now imagine that a specific habitat feature tend to occur every 2000m.  Depending on your starting point, a 2km regular sampling strategies may completely miss the feature out.  It is therefore important to make sure that the interval between survey sites does not correspond to the interval of occurrence of features you want to record.

Selecting your sites

When we put together the first RHS baseline survey in 1994, site selection was done by hand. This required quite a bit of work by a team of people who had to select every site using paper maps and random number tables (for more details click here).  The method used for stratification itself introduced some bias.  Indeed, sites were selected in every 10km-squares by further dividing them into 2km-squares.  A 2km-square would then be chosen at random and the point on the river closest to the centre of the square would represent the midpoint of the RHS site.  This selection method meant that large rivers were more likely to be selected than narrower ones potentially introducing a bias based on river width.

Geographical Information System (GIS) can help automate the identification of suitable river survey sites and reduce sampling bias. GIS can save significant time and money; reducing an intensive manual process which requires a team of people, to an individual pressing a button and obtaining a selection of sites within minutes!

GIS selection is not bias free though!  I have seen algorithms implementing ‘random’ samples by randomly selecting polylines in a river network.  Because polylines will be of different lengths, the sample obtained is likely to be biased towards small polylines (e.g. 1m) that will be over-represented in the network compared to longer ones (e.g. 10km).

To generate random samples for my research, I used RivEX which is an ArcGIS 10.1 AddIn that can automate the sampling of river networks. Provided you possess a valid network (a topologically correct centreline network), you can generate sampling locations using random or regular sampling strategies in RivEX.

With regular sampling you can generate points on the network:

●     for each line of the network

●     at a user specified stepping distance from network mouth

With random sampling you can generate points on the network:

●     by sampling the whole network

●     by stratifying the sampling with a user defined grid

●     by stratifying the sampling with a user supplied polygon layer

Each sampling point generated is snapped to the river network and have attributes of ID, XY coordinates, intersecting polyline ID and in the case of supplying a polygon layer the polygon ID.  The sampling points generated can form the basis for your catchment or river survey but you can also use them to:

●     transfer metrics encoded into the network to the sampling points such as distance to network mouth or Strahler order;

●     query other spatial layers (e.g. geology, land use or authority boundaries);

●     generate catchment boundaries using an appropriate DEM;

●     answer network tracing problems such as identifying the nearest site downstream or upstream.

The tool is scalable allowing you to generate sampling points at a national, regional or sub-catchment level. Figure 1 demonstrates stratified sampling using CCM data for Ireland. A 10Km grid is built and each cell sampled 3 times, the entire process took only 30 seconds!

Figure 1Figure 1. Stratified sampling of rivers in Ireland. RivEX was used to generate a 10Km grid and sampled each cell 3 times. CCM River and Catchment Database © European Commission – JRC, 2007.

With RivEX you can generate regularly spaced sampling points at a user specified distance from the network mouth.  Figure 2 show the river Shannon in Ireland sampled every 10Km. Such a dataset would be vital for a walk over campaign allowing your field surveyors to survey the river at known coordinates.  I personally used this very useful function to extract GIS data for typing rivers and implementing predictive models.

Figure2

Figure 2. Regular sampling of the main stem of the river Shannon, Ireland, with a stepping distance of 10Km. CCM River and Catchment Database © European Commission – JRC, 2007.

Conclusion

Defining a sampling strategy is a very important first step in any project aimed at characterising a river catchment or area.  The choice of sampling strategy, method and intensity as well as the tool used are crucial and require careful consideration with regards to potential biases introduced.  Tools exist that can help with automate the procedures and reduce bias.

For more information, read Jeffers, J. N. R. 1979 Sampling. Cambridge, Institute of Terrestrial Ecology, 7pp. (Statistical Checklist, 2). (Link to publication online)

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.

 

References

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.