Mapping Drainage Canal Density in Southeast Asian Peatlands
Abstract
Extensive land use change has occurred across Insular Southeast Asia (ISEA) peatlands over the last 30 years. The main driver of these changes has been conversion of peatlands to agricultural use. Consequently, networks of drainage canals are often built on plantations and small farms to control water table depth and make the soil suitable for planting. However, the presence of these canals has the negative impact of drying out the upper profile of the peat soils. Drier soils in turn cause increased carbon release to the atmosphere, rapid subsidence, and elevated fire risk. Although canals directly impact local peat hydrology, the effect of drainage intensity (e.g. canal density) in peatlands has not been quantitatively investigated, possibly due to the lack of canal maps in the region.
In this study, we developed an algorithm to identify drainage canals and map their density throughout ISEA peatlands using remote sensing. The algorithm ingests VV- and HV-polarized, 10 m resolution radar backscatter and optical reflectance data from the Sentinel 1 and 2 satellite missions, respectively, in a random forest classifier. To account for the linear shape of canals, we generated texture-based information from the backscatter and reflectance data and include them as input features to the classifier. Training data was generated by labeling random pixels using 5 m resolution Planet Basemap data from 2017. Validation of canal density was performed via comparison to external canal maps. A map of canal density was then produced across ISEA peatlands. We will also include comparisons of canal density with land use and land cover type.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.H13K1857D
- Keywords:
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- 0402 Agricultural systems;
- BIOGEOSCIENCES;
- 1632 Land cover change;
- GLOBAL CHANGE;
- 1803 Anthropogenic effects;
- HYDROLOGY;
- 1836 Hydrological cycles and budgets;
- HYDROLOGY