Engineered Large Wood Structures in Stream Restoration Projects in Switzerland: Practice-Based Experiences

Round 1

Reviewer 1 Report

The paper presents a brief introduction to Large Wood (LW) in rivers and then outlines the morphology of the upland Swiss streams where they have developed and applied the use of LW for bank protection and ecological habitat remediation. From case studies of three projects they identify a useful set of qualitative criteria for the design of LW engineered structures in such streams. The paper is logically structured and well written in good English. The topic is useful and interesting, and the results are worth publishing.

My only concern is that the work is entirely qualitative, making it less readily applicable than it could be. In particular, the basis for the choice of key log diameter and length in each of the case studies would be of interest. I imagine that availability was a major consideration, but available 3m or 3cm diameter logs (to make my point) would not have been considered. So the authors had an acceptable range – what was that range and how was it determined? Answers to these questions help to provide a basis for others to use the work.

Lines 145-8 need substantiation. Was the experience gained in the 3 projects discussed later in the paper, if so say so. Cite any references to this work, even if in the grey literature. If not in the 3 discussed projects, please identify the river and the motivation for using LW/LWS, so that the reader may identify the environments and conditions where this work may be expected to be valid.

 

Minor points

Lines 47-9, 65-8 A brief literature review is welcome but a couple of key early sources could have been added, in particular either Maser et al (1988) or Maser & Sedell (1994). Recent work in Italy could also have been usefully included.

Maser, C., Tarrant, R.F., Trappe, J.M. and Franklin, J.F. (1988). From the Forest to the Sea: A Story of Fallen Trees, USDA Forest Service, Pacific Northwest Research Station, Bureau of Land Management, General Technical Report PNW-GTR-229, 166pp.

Maser, C. and Sedell, J.R. (1994) From the Forest to the Sea: The Ecology of Wood in Streams, Rivers and Estuaries, St Lucie Press, Delray Beach, Florida.200pp.

Fig 6 and the text do not make clear what “rooflike crossed piles” look like.

Section 5.2 The motivation for this project is not stated, except perhaps in lines 331-3 too late in the section.

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 2 Report

The article discusses hydraulic structures made of wood (LWS). Only general information is given about artificial structures that imitate natural logjams on small rivers. No specific information is provided on the types of artificial structures, their volume, distances between structures, depending on the size and morphology of the river channel, on hydrological regimen. Table data. 1 for the Oregon rivers are completely inadequate for practical use. Of the three examples of work already performed on the rivers of Switzerland, only one refers to structures that simulate natural logjams. Even here it is not clear how many such structures should be placed along the river and in what places. The other two examples relate to structures of the type commonly found on medium-sized rivers. These structures were not discussed at all in the article, there is also no specific information required for the project.

The paper requires:

1) Specific information for artificial structures that imitate natural log jams on small rivers, their types, volumes, distances between structures and cost, depending on the size and morphology of the river channel and hydrological regimen.

2) Evidence that such structures should be created precisely from wood, and not stone, concrete, etc.

If the article includes structures on medium-sized rivers, for these structures justifications are also required according previous two points.

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

My main comment was:

“The article discusses hydraulic structures made of wood (LWS). Only general information is given about artificial structures that imitate natural logjams on small rivers. No specific information is provided on the types of artificial structures, their volume, distances between structures, depending on the size and morphology of the river channel, on hydrological regimen”.

The authors of the article argue that:

“In the context of this special edition of the Water journal we were asked by the guest-editors for a practice based contribution. Based on our background as civil engineers working in planning processes and on site we decided to focus on questions and challenges encountered during the planning process and during the execution phase that are related to our daily business.”

and

“We've added an explanation in lines 192-195 stating that we explicitly do not give answers to these specific questions to underline our intention. In lines 226-229 we state that naturalness of LWS is a key aspect. We therefore cannot provide information for the definition of standardised LWS”.

 

So, no practical recommendations were included into this article after revision. It is still unclear to the reader where and how these structures can and should be constructed. There were provided only general words about usefulness and naturalness of LWS. This information is not novel and can not be used for practical needs. The article turned out to be more popular than scientific and therefore, hardly suitable for an academic journal

Author Response

Please see the attachment

Author Response File: Author Response.pdf