On modeling hyporheic dissolved oxygen, temperature and nitrogen dynamics in gravel bed rivers
Event details
| Date | 16.04.2013 |
| Hour | 16:15 › 17:15 |
| Speaker | Dr Alberto Bellin, Department of Civil, Environmental and Mechanical Engineering, University of Trento, IT |
| Location | |
| Category | Conferences - Seminars |
Dissolved inorganic nitrogen (DIN), naturally a limiting element in pristine watersheds, has received recently great attention because of its increasing concentrations in water bodies due to anthropic activities. DIN concentrations regulate riverine ecosystems and organisms’ metabolism with important processes occurring in hyporheic, riparian and parafluvial zones, whose biochemistry is influenced by subsurface flow patterns. Although a large body of experimental evidences confirms this, most of the models used to represent nutrients cycling in fluvial ecosystems lump these processes in a single diffusion-type exchange term. In this seminar I discuss a new modeling approach, which overcomes this limitation. In particular, I will discuss a three-dimensional semi-analytical process-based model that couples hyporheic flow patters with dissolved oxygen and DIN biochemical processes within the streambed sediment. Flow patterns, are obtained analytically, with a few simplifying assumptions, from the streambed topography and solute transport is modeled within a Lagrangian framework chiefly as an advective process with temperature-dependent reaction rate coefficients derived from field experiments. In addition, I will discuss the application of this model to investigate the role of hyporheic flow induced by alternate bars - an ecologically important and ubiquitous bed form in both regulated and natural streams - on DIN dynamics. This modeling approach allows to investigate the effect of bedforms, alluvium depth, hyporheic water temperature and relative abundance of ammonium and nitrate in stream waters on DIN dynamic. Published results demonstrate how the model can be used to estimate nitrogen gas emissions from rivers.
Practical information
- General public
- Free
- This event is internal
Organizer
- IIE
Contact
- Professor Andrea Rinaldo, ECHO