From: Chris Stolker To: Subject: Rivers-List: Roughness of flexible submerged vegetation Date: 15 August 2000 08:58 Dear IAHR-colleagues, The roughness of floodplain vegetation is a matter of continued interest for anyone dealing with river management and river restoration. In this respect we have a request to everybody engaged in this topic. Within the framework of the development of a handbook for vegetation roughness in floodplains by Public Works Department, The Netherlands, we are preparing a data base with results of flume and prototype measurements of the roughness of (flexible) submerged vegetation. Therefore we are trying to identify and locate well documented (older and more recent) studies on the roughness of this type of floodpain and marsh vegetation, in order to include the measuring data into our database. We will also include vegetation in weeded canals as far as it can help us in improving our understanding of the roughness of submerged plants. Our main interest though is flexible, low vegetation like grasses, reeds, and other marsh vegetation, which is substantially submerged during flood conditions. We are not intending to include data on rigid vegetation like willows and trees. In principle our interest is natural plants, but we will include as a side activity also data on artificial "plants" like rods and strips. Preferably the sets of data should include: · type of vegetation (Latin name, if available) plus its characteristics (length, stem thickness, EI (if available), density, leave characteristics (if any), etc.); · (unit) discharge and/or average velocity; · flume width; · water depth; · slope; · detailed vertical velocity profiles (if available) plus information about measuring procedures and accuracies. If available we would appreciate receiving a copy of the relevant report(s), also when it is written in another language than English, German or French. If required we can reimburse the costs of copying original reports. If appropriate, please add an invoice and indicate the method of payment. We have already started the preparation of a data set, and for the time being it is (of course) limited to literature we could identify until now. We have attached to this email a list with all literature presently available to us. If you are aware of other detailed and well-documented studies on the roughness of (flexible) submerged vegetation we would appreciate if you would let us know. Also if you know persons or institutes who are involved in research on this subject, we would appreciate if you would inform us accordingly. Thank you very much for spending some of your valuable time on this matter. To compensate you for this, we can offer to anyone providing us with additional data a copy of the data set, once finished, for use in your own investigations. Kind regards, Chris Stolker & Gerrit J. Klaassen Delft Hydraulics, P.O. Box 177 2600 MH Delft The Netherlands e-mail: Chris.Stolker@wldelft.nl tel.nr: +31 15 285 8471