Incorporating land-use changes and surface-groundwater interactions in a simple catchment water yield model

  • Authors:

  • M. Gilfedder;D. W. Rassam;M. P. Stenson;I. D. Jolly;G. R. Walker;M. Littleboy

  • Affiliations:

  • CSIRO Water for a Healthy Country National Research Flagship, CSIRO Land and Water, PO Box 2583, Brisbane, QLD 4001, Australia and eWater Cooperative Research Centre, University of Canberra, ACT 2 ...;CSIRO Water for a Healthy Country National Research Flagship, CSIRO Land and Water, PO Box 2583, Brisbane, QLD 4001, Australia and eWater Cooperative Research Centre, University of Canberra, ACT 2 ...;CSIRO Water for a Healthy Country National Research Flagship, CSIRO Land and Water, PO Box 2583, Brisbane, QLD 4001, Australia and eWater Cooperative Research Centre, University of Canberra, ACT 2 ...;eWater Cooperative Research Centre, University of Canberra, ACT 2601, Australia and CSIRO Water for a Healthy Country National Research Flagship, CSIRO Land and Water, Private Mail Bag 2, Glen Osm ...;eWater Cooperative Research Centre, University of Canberra, ACT 2601, Australia and CSIRO Water for a Healthy Country National Research Flagship, CSIRO Land and Water, Private Mail Bag 2, Glen Osm ...;eWater Cooperative Research Centre, University of Canberra, ACT 2601, Australia and Scientific Service Division, Office of Environment and Heritage, NSW Department of Premier and Cabinet, PO Box 7 ...

  • Venue:
  • Environmental Modelling & Software
  • Year:
  • 2012

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Abstract

Pressure on limited water resources and the environment requires better understanding of how landscape change impacts river flow. Rainfall-runoff models have traditionally focused on estimating total river flows with less emphasis on modelling the groundwater component or the consequences of different land-use change scenarios. In this paper, we present the GWlag model, a water-generation model that predicts river flows with explicit accounting of the impacts of catchment land-use change and surface-groundwater interactions. The paper firstly describes the theory that underpins the model and its calibration then presents a case study application in the Tarcutta Creek catchment of the Murray-Darling Basin, Australia. The case study aims at: (i) demonstrating the ability of the model to predict daily river flows; (ii) modelling the impacts of hypothetical plantation forestry expansions on river flows; and (iii) showing the impacts of reduced recharge on the low-flow regime using three indices, namely, Q"9"0/Q"5"0 (where Q"n refers to nth percentile flow), slope of low-flow part of flow duration curve, and % of zero-flow days. Results showed that predicted flows agreed favourably to those observed at the gauge especially during low-flow conditions. The hypothetical plantation expansion from 32% to 87% of the catchment area has resulted in reductions of 48% and 32%, in Q"5"0 and Q"2"0, respectively. The low-flow indices demonstrated the great sensitivity of low flow to reductions in recharge with the trend of the low-flow response changing to non-linear for recharge reductions beyond 10%. GWlag daily river flow predictions compared favourably to those obtained from four other rainfall-runoff models in terms of the Nash-Sutcliffe model efficiency (E). However, GWlag produced the highest E-value for log-transformed flows thus highlighting the model's superior predictive capability during low-flow conditions.