IP 2 - Project

Analysis of short term in-situ erosion rates by image-based measurement systems (ASTIRI).

While long term erosion rates may be estimated by dating methods, current day erosion rates are – if at al available – based on rough estimates or on point measurements. Precise quantification of short term erosion rates are required to improve our understanding of short term processes, for input in landscape evolution models, as well as for studying the mechanics and efficiency of different erosion processes in varying geomorphological settings. Typical current day erosion rates in the European Alps range from sub-millimetre to several millimetres per year depending on the dominant erosion processes. IP2 will utilize a new innovative surveying technology for quantification of in-situ bedrock incision in fluvial channels of the Swiss Alps.

The level of surveying accuracy required for recurring sub-millimetre to millimetre measurements of the same area in the field is demanding. Point probing techniques require a rock anchor as reference point disturbing the vicinity of the sampling area and such measurements are only valid for a very limited part of a bedrock channel. A precise method for quantification of areas larger than 1 m2 with sub-millimetre accuracy is “badly needed”, but not available off the shelf. The method should be non-contacting as well as non-disturbing and suitable for field use even in remote areas. Latest developments with image assisted measurement techniques will be utilized to provide such a method. It combines the pointing precision of a theodolite with the ability of mass point measurement from stereo imagery.

The input of IP 2 to SedyMont is:

  • Optimization of an image assisted total station system for measuring in-situ bedrock incision with submillimetre accuracy. 
  • Quantification of in-situ bedrock incision in fluvial channels of the Swiss Alps. Test sites are Erlenbach, Rotenbach and Illgraben (all in Switzerland).

The objectives require development and implementation of an image assisted total stations (IATS) for measurement of bedrock erosion. Main test site will be the derbis flow channel of the Illgraben. An annual average of 3-5 debris flows have been observed in the Illgraben. Bedrock erosion in the channel is at the order of 1 mm per event (personal observation). Frequency and magnitude of debris flow events in the Illgraben should provide sufficient basis for evaluation of the IATS method as well as for accurate quantification of in-situ bedrock erosion over the duration of the project. Additional data will be collected in the Flysch bedrock of Erlenbach and Rotenbach catchments. Estimated erosion rates in the fluvial channels are less than in the debris flow channel of the Illgraben, but should exceed 1 mm per year.

The main goal of IP2 is to develop, implement and provide an image-based measurement system for the task for quantification of bedrock erosion in fluvial channels. The derived data will support the analysis of IP1.

The IP 2 aims can be formulated as follows:

  • Develop a measurement system which is based on image sensors – we plan to research and implement an image and feature fusion procedure – use correlation of redundancy of different kinds of data and features derived from measurements from IATS. 
  • Along with the use of new sensors comes the direct necessity to research, develop and implement new sensor models and new software concepts. Therefore in this project a profound analysis and a subsequent software prototype development process – on the basis of existing software components – is envisaged. 
  • The software modules, which have been developed in other projects (point detection, image processing, deformation assessment, etc.) will be adapted and integrated into the new measurement process. Especially the two FWF research projects P14664 “Theodolit-based and Knowledge-based Multi-Sensor-System”) and P18286 (“Multi-Sensor Deformation Measurement System Supported by Knowledge-Based and Cognitive Vision Techniques”) can be used as input for the project at hand. 
  • Development and integration of a suitable component, able to control the sensor(s) and the single system modules and providing a suitable user interface (if more than on sensor is used they have to be synchronized, captured data has to be managed, etc.). 
  • Development of a user interface in close collaboration with earth scientists for field use by trained expert users from different applied disciplines. 
  • Quantification of bedrock erosion in fluvial channels on an event basis to support the work of IP1.
 
© 2009 SedyMONT | CSS | XHTML