Pre-restoration study

In order to evaluate the ecological effects of the advanced restoration a pre-restoration study was conducted during the summer of 2010 and partly 2011, i.e. before the advanced restorations had begun. A follow-up study was done after the restoration in 2011. The processed results showing the hydro-geological changes that restoration causes can soon be read in an article in Ecology and Society.

Data sampling was carried out in one stretch of rapids in each of the 10 demonstration sites and in one stretch of rapids in each of 10 reference sites. The reference sites have been targeted by best-practice restoration and are located in the same channel as the demonstration site, though upstream or in a tributary nearby within the same watershed. The indicators measured were current velocity, depth, substratum size, edge-to-area ratios, and a visual classification of the characteristics of the stream. In addition, electro fishing was also conducted in order to estimate the density of Atlantic salmon, bullhead, brown trout and European brook lamprey.

The measurements were performed in July 2010, in medium flow condition and in August, in low flow condition. The follow-up measurements were done 2011.

Current Velocity
Current velocity was measured at 10 cross sections evenly distributed along every reference and demonstration site. The measurements were performed 60 cm below the water surface in 5 verticals along the cross section, i.e., at 50 points per site.

The width of the channel (the length of the profile) was measured at each profile so the mean stream width (m) could be calculated.

The discharge was measured in a stream cross-sectional profile above a relatively homogeneous and narrow bottom. Initially, the depth and width of the cross-section profile were measured to estimate its area. Thereafter the current velocity was measured in 7-11 vertical measurements within the profile. Area (m2) x Current Velocity (m/s) gives the discharge (m3/s).

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