An empirical approach to predicting effects of climate change on stream water chemistry
Location
Eccles Conference Center
Event Website
http://water.usu.edu
Start Date
4-2-2014 2:15 PM
End Date
4-2-2014 2:30 PM
Description
Climate change may affect stream solute concentrations by three mechanisms: dilution associated with increased precipitation, evaporative concentration associated with increased temperature, and changes in solute inputs associated with changes in climate-driven weathering. We developed empirical models predicting base-flow water chemistry from watershed geology, soils, and climate for 1976 individual stream sites across the conterminous USA. We then predicted solute concentrations for 2065 and 2099 by applying down-scaled global climate model predictions to these models. The electrical conductivity model (EC measures total dissolved solids) predicted mean increases in EC of 21 µS/cm (32%) by 2065 and 42 µS/cm (57%) by 2099. However individual stream responses ranged from 50% decreases to 4x increases. The greatest decreases occurred in southern Rocky Mountain and Mid-West streams, whereas southern California and Sierra Nevada streams showed the greatest increases. Generally, streams in dry areas underlain by non-calcareous rocks were predicted to have the greatest increases in EC with climate change. Predicted changes in other solutes (e.g., SO 4 and Ca) were similar to EC, although the magnitude of SO4 change was greater.
An empirical approach to predicting effects of climate change on stream water chemistry
Eccles Conference Center
Climate change may affect stream solute concentrations by three mechanisms: dilution associated with increased precipitation, evaporative concentration associated with increased temperature, and changes in solute inputs associated with changes in climate-driven weathering. We developed empirical models predicting base-flow water chemistry from watershed geology, soils, and climate for 1976 individual stream sites across the conterminous USA. We then predicted solute concentrations for 2065 and 2099 by applying down-scaled global climate model predictions to these models. The electrical conductivity model (EC measures total dissolved solids) predicted mean increases in EC of 21 µS/cm (32%) by 2065 and 42 µS/cm (57%) by 2099. However individual stream responses ranged from 50% decreases to 4x increases. The greatest decreases occurred in southern Rocky Mountain and Mid-West streams, whereas southern California and Sierra Nevada streams showed the greatest increases. Generally, streams in dry areas underlain by non-calcareous rocks were predicted to have the greatest increases in EC with climate change. Predicted changes in other solutes (e.g., SO 4 and Ca) were similar to EC, although the magnitude of SO4 change was greater.
https://digitalcommons.usu.edu/runoff/2014/2014Abstracts/49