Water quality and climate change
description
Transcript of Water quality and climate change
Water quality and climate change
Dr Glenn Watts
Evidence Directorate
19 March 2011
Structure
Drivers of change in water quality
Possible impacts
Modelling - scale and thresholds
Implications for adaptation
Drivers – temperature
2080s medium emissionsSource UKCP09
Rainfall
2080s, medium emissionsSource UKCP09
Winter flows
2050s medium emissions, long term average changes
Source CEH – Environment Agency “future flows”
Summer flows
2050s medium emissions, long term average changes
Source CEH – Environment Agency “future flows”
Possible impacts of climate change on water quality
Mobility and dilution of contaminants
Chemical reaction rates
Sediment mobilisation, transport and deposition
Impacts in Wales
Urban dischargesFlashy riversReduced dilution
AgricultureNutrient leaching
UplandsDissolved organic carbon and colourSediment loads and depositionAcidification – from intense rainfall and droughts
LakesTemperature and eutrophication
Mine waste mobilisation
Modelling questions: scale
field
reach catchment
Modelling questions:thresholds
Do current approaches cope with changes of state?
Empirical and conceptual models
State change
threshold
input
response
Climate change adaptation
Uncertainty cascade
Climate model
Hydrological model
Chemical model
Ecosystem model
Approaches to adaptation
Best estimate plus uncertainty
Scenario planning – exploring risk tolerances
Probabilistic approaches
Climate sensitivity
Why examine the impact of climate change on water quality?
To inform effective adaptationUnderstand possible impacts
Evaluate different management responses
Improve approaches to regulation
A strategy for adaptation
Willows and Connell 2002
Further research
Processes and responses
Thresholds and climate sensitivity
Links from field to catchment scale
Possible adaptation measures
Catchment scale management measures
Summary & conclusions
Climate change affects flow and thermal regimes
Water quality response complex
Questions: field scale to catchment scale
thresholds and climate sensitivity
Do we understand adaptation measures?