Abstract Estimates of rainfall elasticity of streamflow in 219 catchments across Australia are presented. The rainfall elasticity of streamflow is defined here as the proportional change in mean annual streamflow divided by the proportional change in mean annual rainfall. The elasticity is therefore a simple estimate of the sensitivity of long-term streamflow to changes in long-term rainfall, and is particularly useful as an initial estimate of climate change impact in land and water resources projects. The rainfall elasticity of streamflow is estimated here using a hydrological modelling approach and a nonparametric estimator. The results indicate that the rainfall elasticity of streamflow (ϵ P ) in Australia is about 2.0–3.5 (observed in about 70% of the catchments), that is, a 1% change in mean annual rainfall results in a 2.0–3.5% change in mean annual streamflow. The rainfall elasticity of streamflow is strongly correlated to runoff coefficient and mean annual rainfall and streamflow, where streamflow is more sensitive to rainfall in drier catchments, and those with low runoff coefficients. There is a clear relation-ship between the ϵ P values estimated using the hydrological modelling approach and those estimated using the nonparametric estimator for the 219 catchments, although the values estimated by the hydrological modelling approach are, on average, slightly higher. The modelling approach is useful where a detailed study is required and where there are sufficient data to reliably develop and calibrate a hydrological model. The nonparametric estimator is useful where consistent estimates of the sensitivity of long-term streamflow to climate are required, because it is simple to use and estimates the elasticity directly from the historical data. The nonparametric method, being model independent, can also be easily applied in comparative studies to data sets from many catchments across large regions.
[1]
V. Singh,et al.
Application and testing of the simple rainfall-runoff model SIMHYD
,
2002
.
[2]
P. E. Waggoner,et al.
From climate to flow.
,
1990
.
[3]
Francis H. S. Chiew,et al.
Modelling the impacts of climate change on Australian streamflow
,
2002
.
[4]
F. I. Morton.
Operational estimates of areal evapotranspiration and their significance to the science and practice of hydrology
,
1983
.
[5]
R. Moran,et al.
Impact of Climate Changes on the Security of Water Supply of the Campaspe System
,
1999
.
[6]
Chong-Yu Xu,et al.
Climate Change and Hydrologic Models: A Review of Existing Gaps and Recent Research Developments
,
1999
.
[7]
John O. Carter,et al.
Using spatial interpolation to construct a comprehensive archive of Australian climate data
,
2001,
Environ. Model. Softw..
[8]
T. McMahon,et al.
Assessing the adequacy of catchment streamflow yield estimates
,
1993
.
[9]
J. Nash,et al.
River flow forecasting through conceptual models part I — A discussion of principles☆
,
1970
.
[10]
A. Sankarasubramanian,et al.
Climate elasticity of streamflow in the United States
,
2001
.
[11]
R. Srikanthan,et al.
Simulation of climate change impact on runoff using rainfall scenarios that consider daily patterns of change from GCMs
,
2003
.
[12]
James P. Hughes,et al.
A spatiotemporal model for downscaling precipitation occurrence and amounts
,
1999
.
[13]
Murray C. Peel,et al.
National Land and Water Resources Audit Theme 1-Water Availability Extension of Unimpaired Monthly Streamflow Data and Regionalisation of Parameter Values to Estimate Streamflow in Ungauged Catchments
,
2000
.