Catchments control how water is stored, mixed and how discharge and solutes are released. Spatio-temporal water quality dynamics are controlled by variations of source areas (dependent on storage and connectivity), hyporheic exchange processes and by changing biogeochemical in-stream processes.

Depending on:
- the spatio-temporal dynamics of catchment storages and
- their connectivity to the stream network,
- physiographic catchment properties and
- past and future inputs of precipitation and solutes,
these catchment functions determine multiple hydrologic and ecological processes, such as major ion composition, nutrient turnover, organic contaminants and suspended sediments. However, the time variance in catchment storage and the variability in precipitation often lead to highly non-linear catchment responses that make runoff generation and hydrochemistry challenging to predict.

In this session we bring together catchment hydrologists and stream-/ecohydrologists who study these processes at different scales. We present experimental and modeling studies that analyze the role of catchment storage, catchment mixing and hyporheic exchange fluxes and determine how they control hydrologic and hydrochemical catchment response in time and space.

Invited Speakers:
James Kirchner, ETH Zürich
Matthias Sprenger, University of Aberdeen