Within Improve Aquatic LIFE, the County Administrative Board of Värmland is working to reduce the risk of erosion and sediment transport in the Billan and Likan rivers. By mapping ditches, planning ditch plugging and measuring water flows, the habitat for mussels, fish and crayfish will be improved, while taking into account forest production and landowners’ interests.
In Värmland County, the County Administrative Board is working in Improve Aquatic LIFE within the work package Improve Hydrological Regime (WP5) in Billan ARO to plan measures that will reduce the risk of damage to the habitat for mussels, fish and crayfish in the Billan river.
Eroding “moat” to ditch flowing into tributary of Billan.
A few large, and many smaller ditches have been discovered where erosion causes the transport of sediment into the river.
Plugging will, in some cases, equalize the flow of water to Billan as it enters naturally meandering stream channels, or filters through the ground.
Ditches that can be plugged will act as the “guardrail” in the tractor path in the image below, causing any sediment transported with water in the ditch to stay there or end up on land next to the ditch. Plugging will in some cases cause the flow of water to Billan to equalize as it enters naturally meandering stream channels, or filters through the soil.
Eroding ditch that flows into Billan.
“Local delta formation” at the mouth of a ditch in Billan.
Driving track with bridge built over tributary to Billan.
In the Likan ARO (3 images below), ditches have been mapped, sub-catchments identified and plans for measuring water flows and water chemistry conditions planned. Ditch plugging has been simulated via computer models and suggests that water flow to Likan would be equalized. Future measurements of water flow will hopefully show whether this is the case. Work to identify potential conflicts of interest with forest production is ongoing and will be reported to Stora Enso, and other landowners.
Likan ARO. Many and long ditches that do not benefit either the environment or forest production.
Likan ARO. Simulated actions suggest that the amount of water in wet areas may increase after trench plugging. Blue areas in the image are wet before plugging, the light green shows how the “blue” is increased after plugging. Runoff pathways are also changed and should contribute to slowing the path of water from source to river (not shown in the image). The purple-dashed area indicates the boundaries of a sub-catchment.