Nature restoration stories: Rewetting drained peatland to improve biodiversity
- Naturgenopretning
What does rewetting mean? Why is this important? And how is SCALGO Live used for successful rewetting? Ea Baden from Ekologigruppen talks about how they plan peatland restoration with SCALGO Live.
Ekologigruppen is a consulting company with strong values based on ecological, social and economic sustainability. The company operates in an interdisciplinary manner and is a driving force in knowledge and method development in green urban planning and nature conservation.
Ea Baden, an environmental scientist and human ecologist, is specialising in nature conservation measures. Among other things, she works a lot with rewetting drained peatland.
"Rewetting is today used as a term for the restoration of wetlands that form peat, or have formed it, and have been drained for the benefit of peat collection, forest production or agriculture", says Ea. "The goal of rewetting is usually to create better conditions for biodiversity or reduce emissions of carbon dioxide."
For example, when rewetting peatlands by raising the groundwater level, the release of greenhouse gasses is slowed down. Raising water levels above the ground by damming, and creating open water surfaces, improves biodiversity in the area. However, on peatlands, damming can also lead to an increase in methane emissions.
"We use SCALGO Live to carefully analyse the topography and find areas where we can achieve a lot of rewetting with just a few small dams."
Ea Baden, Ekologigruppen
Figure. Out measuring ditches. To rewet the area, ditches are blocked with local materials creating dams where water rises upstream.
"Bogs that have been drained have trees growing along the ditches. If the ground is rewetted, trees do not grow that well anymore," explains Ea, "and that is how we create open areas that benefit wildlife, such as wading birds. In the wetter environment, the sphagnum moss also grows better. In this way, we improve biodiversity."
How you choose to do the rewetting depends on the goal of the specific project. Here, Ea and her colleagues help develop the most appropriate plan.
Rewetting involves placing small peat dams in the ditches with materials that are available in the area. The usual method is to cut down trees locally, place them in the ditch and fill the ditch with peat.
"This causes the water level to rise upstream from the peat dam."
Figure 3. Placing the dams in SCALGO Live. The small black lines are peat dams.
When placing peat dams, topography is very important. By strategically placing the dams, Ea and her colleagues aim at creating as much rewetting as possible.
"We use SCALGO Live to carefully analyse the topography and find areas where we can achieve a lot of rewetting with just a few dams. We place the dams in SCALGO Live to show how the project should be carried out", Ea describes the work process. "When we place dams, we also think about costs - we want to create a lot of rewetting with as few dams as possible".
Figure 4. The dams are placed after careful analysis of the topography.
In addition to the topography, it is interesting to look at historical maps. It is not always possible to see all the ditches in the elevation model because they may have become overgrown, but in historical maps you can often see the original location of the ditches. Then you can use terrain editing in SCALGO Live to draw the old ditches into the topography and, thereafter, place peat dams.
"What is also interesting in these projects is that you often have the wrong idea of where the water comes from or what it looked like a long time ago, before the area was drained", Ea reasons. "We might think that an area has been a wet bog with no real runoff, but when we look at the area more closely, we realise that there has always been runoff. SCALGO Live helps us understand and explain the history."
