Catchment critical zone controls on groundwater contributions to surface water chemistry variability
Abstract
Longitudinal variability in stream water chemistry is driven by the accumulation of watershed runoff contributions that reflect both the fingerprints of a catchment's critical zone and stream corridor surface water-groundwater (SW-GW) exchanges. However, the catchment and stream corridor SW-GW domains are typically examined independently despite the need to understand both in order to accurately interpret longitudinal riverine water chemistry. Here, we assess the roles of catchment and critical zone contributions along the stream network in influencing surface water chemistry in a snow-dominated headwater catchment at the Tenderfoot Creek Experimental Forest, MT, USA. We relate reach scale measurements of stream discharge and changes in discharge (gross gains and losses) to point scale measurements of stream water chemistry synoptically sampled across the entire riverine network three times within a single summer baseflow recession period. Our results begin to identify the relative influences of watershed shape (lateral streamflow contributing areas), riparian buffering of hillslope water, lithology, and the degree of large scale SW-GW exchange in influencing the spatial variability in stream water chemistry. We suggest that consideration of watershed and critical zone structure surrounding the stream network is key to accurately assessing both GW-SW exchange and spatial variability and observed stream water chemistry.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.H23D..01Z
- Keywords:
-
- 0414 Biogeochemical cycles;
- processes;
- and modeling;
- BIOGEOSCIENCES;
- 0496 Water quality;
- BIOGEOSCIENCES;
- 1830 Groundwater/surface water interaction;
- HYDROLOGY;
- 1839 Hydrologic scaling;
- HYDROLOGY