PEATLAND WATERCOURSE ANALYSIS
4th May 2021
To test an application of Digital Terrain Mapping (DTM): mapping and assessing the flowpaths of watercourses through areas of peatland. This will assist in the restoration and preservation of peatland ecosystems for carbon sequestration, water quality and flood mitigation purposes.
Recent studies have highlighted the potential capacity of healthy peatland ecosystems to lock away a disproportionately large amount of carbon. Conversely degraded peatland can act as a carbon source; emitting greenhouse gases into the atmosphere. As such, the conservation of these ecosystems is particularly integral to this country's ongoing attempts to mitigate the wider impacts of climate change.
As traditional wisdom has deemed peatland to hold little commercial value, large areas have been subject to including; drainage, peat-cutting, grazing and burning activities - usually starting with the practice of artificial drainage. Anthropogenic pressures have led to the degradation of these carbon stores - as to maintain their large carbon capacity areas rely on wet conditions for biological balance.
Introducing artificial drainage systems disrupts this balance, but the effects can be reversed using ecohydrological restoration - assessing the most significant watercourses in the area and stemming their drainage outlets. Sweeping across vast, relatively undisturbed areas of peatland, a UAV can quickly gather imagery to generate a Digital Terrain Map (DTM), which can then be interpreted to generate a flowpath polyline shapefile of the area that clearly displays the most significant water courses through the area.
Whilst gathering imagery for our national orthomosaic project, we had the opportunity to capture elevation data for an area of Scottish peatland to test our process: we used the Strahler order of stream classification to pose the query "if an even amount of precipitation fell across this area, where would gravity lead the channels to flow"? The results that the test returned clearly displayed the most significant watercourses in the area, while also showing the smaller streams and channels that flowed into them that were not immediately obvious, even on our hi-res 3.32cm/px orthomosaic.