Field observations in late August 2014 in Iceland suggested that infiltration was limited by deep volcanic ash on hillslopes which caused ponding and surface runoff rather than groundwater flow. Because of the rocky, mossy, grassy ground, pipeflow (or macroflow-opening) did occur but that there were incidents where ash blocked some of these pipes, and that they did not re-open until high intensity rainfall events occurred. Presently, there is limited information on the role of ash on infiltration processes and macropore flow in arctic hillslope catchments, and the role that they play in both surface and subsurface flow, especially in an environment that is also modified by sporadic permafrost and the occurrence of local thermal groundwater (or hot spots).

Objectives of Harold’s MSc work:

1. Study the infiltration patterns of typical ground types found in small hillslope catchments impacted by tephra fall-out and ensuing aeolian deposits;
2. Study the runoff processes of various sized hillslope macropores (small to large) occurring in different regions of small hillslope catchments (level, plateau, slopes, break-of-slopes, stream catchment) in response to varying rainfall events (light to heavy), different soil horizons (soil over rock;
3. Utilize runoff models developed for cold regions to better understand infiltration and pipeflow runoff processes, especially in areas inundated by volcanic or ash deposited by winds or moved by water.