Integration of climate change and land‐use scenarios in nutrient leaching assessment

The objective of this paper is to describe an easily understandable integrated modelling framework for analysing the combined effects of changes in land‐use and climate on the leaching of phosphorus using regional IPCC‐based land‐use and climate scenarios. In addition, the paper reflects on the added value of a geospatial data‐based modelling approach from a river basin management perspective.

Regional land‐use scenarios were simulated for the whole official river basin planning unit of the Oulujoki‐Iijoki River Basin District using a land‐use simulation model. The nutrient leaching modelling on phosphorus was carried out in another raster‐based freeware for a smaller sub‐basin, Temmesjoki river basin.

Regional land use scenarios could be simulated taking into account the local conditions, such as the vicinity to water, and development options in agriculture on regional scale. The magnitude and leaching pattern of phosphorus in the future is related to the overall share of agricultural land on drainage basin level. The authors’ results also indicate that the local spatial structure of built‐up and agricultural areas may play a central role in nutrient leaching assessment. If the spatial structure is of importance, this may have further implications for the environmental planners working with river basin management.

This research takes a step further in bringing the global scenario framework to the local and practical level for various practical purposes in river basin management. The research provides an approach to spatially identify the possible impact of changes in land‐use and in climatic conditions on nutrient leaching.