A Danish classification system and database for river restoration projects
To obtain a useful overview of river restoration projects undertaken in order to guide future projects in the right direction it is important to continuously undertake systematic collection of project statistic and information.
Therefore, the Danish Centre for River Restoration in co-operation with the Danish counties and the British River Restoration Centre (RRC) , have developed a river restoration classification system and created a database on Danish river restoration projects.
The database is based on a classification system, which differentiates between 'Types' and 'Methods'. Each restoration project is divided into one of three types according to the overall objectives of the project based on the extent of restoration within the river system (Figure 1).
Figure 1. Schematic definition of the three types of restoration projects describing the primary objective of the project.
Type 1: Restoration of watercourse reaches; encompasses projects whose objective is local improvement of shorter reaches, typically resulting in better habitats locally, both in the river and in its nearest surroundings.
Type 2: Restoration of continuity between watercourse reaches; encompasses projects aimed at ensuring free passage along river systems, reconnecting reaches and restoring free passage and continuity.
Type 3: Restoration of river valleys; encompasses projects affecting both the watercourse and its whole river valley ensuring an ecological and hydrological entity.
Each 'type' encompasses a number of 'methods' that have been used to achieve the objective of the project.
The classification system and database is further described and explained in Hansen (1996) (downloadable in pdf)..
The database contains the following information on all projects: name of the stream and stream system, UTM - co-ordinates, restoration code according to the systematic, year of conclusion. Furthermore, the price of the project, the discharge, the catchment area and other information are included for some of the projects.
According to the database a total of 1068 river restoration projects have been carried out throughout the Danish counties up to and including 1998. In addition the Danish municipalities and private organisations have carried out a substantial number of restoration projects.