Greenwood, AJ Title

251 Pages·2017·6.62 MB·English

Minerva Access is the Institutional Repository of The University of Melbourne

Author/s:
Greenwood, A. J.

Title:
Assessing hydrological interception by plantation forestry for application in water resources
management

Date:
2017

Persistent Link:
http://hdl.handle.net/11343/124187

File Description:
Assessing hydrological interception by plantation forestry for application in water resources
management

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UNIVERSITY OF MELBOURNE
SCHOOL OF LAND AND ENVIRONMENT

Assessing Hydrological Interception
BY
Plantation Forestry
FOR
Application
IN
Water Resources Management

A. J. GREENWOOD

Submitted in fulfillment of the requirements of the degree of Doctor of Philosophy

13 February 2017
ANNO DOMINI NOSTRI IESU CHRISTI

IDIBUS FEBRUARIAS MMDCCLXX
ANNO URBIS CONDITAE

Abstract
IN the early to mid-1990s, Australia governments adopted significant forestry and water policy
agendas. The forest policy stimulated plantation expansion, and articulated benefits to water
resource degradation which became a focus of the water agenda. The prospect of changing water
availability during a severe drought resulted in the National Water Initiative (NWI), which sought
to protect the integrity of water entitlements from plantation expansion.
State government agendas provided additional complexity, notably in South Australia where
forest water use became subject to regional regulation in 2004, reminiscent of South African
experiences in 1972. Inconsistencies between assessments used to support/contest the
sustainability of plantation developments resulted in the amendment of South Australian
planning frameworks, to ensure competing policy issues were addressed in a balanced manner.
Mixed progress in implementing the interception clauses of the NWI have been relegated to
unfinished business without critically evaluating its capacity to deliver the required policy and
scientific outcomes. Here, national and jurisdictional forest water policies are analysed and
weaknesses identified in the lack of a cohesive national policy agenda arising from jurisdictional
independence under the Australian Constitution. Inefficiencies in implementation are traced to:
competing agendas; the complexities of their inter/intra-jurisdictional administration; a lack of
regard to relevant international precedents and a tendency for Australian water reform to be
initiated as short-term responses to predictable disasters rather than long-term planning.
Reforms under the NWI are found to have had little direct effect in progressing jurisdictional
forest water management agendas.
Australian empirical hydrological assessment approaches used to support forest water decision-
making are examined in the context of international systems and learnings from South Africa. An
approach for evaluating and transparently integrating Australia’s limited forest hydrology datasets
with modelled information is developed to improve confidence in decision-making.
A similar group of empirically-based models are subjected to a comprehensive Bayesian
evaluation with South African and American approaches to identify an option with the greatest
integrity to underpin current Australian forest water management. Systemic limitations in a
widely used approach developed by a leading Australian research organisation are confirmed and
revealed as being compounded by weak model structure, highlighting the challenges faced by
water management agencies in securing research to support defensible decision-making.
page | 3
Challenges associated with agency capacity limitations and the inevitability of using more complex
modelling in supporting future Australian forest water management are addressed by noting
South African learnings which identify the importance of growth in plantation water use; and
exploring the feasibility of using simpler elements of a sophisticated Bayesian assessment to
establish confidence in a plant growth model. Complexity introduced into the 3-PG plant process
model is shown to improve the model’s ability to extract information from data providing greater
confidence in its potential for future development as a water management tool than more
exhaustive, integrated assessments focused on marginal improvements in performance.
Results are discussed in the context of water management and their implications for future
research and policy developments.
Declaration
I hereby certify that: this thesis comprises only my original work towards the PhD except
where indicated in the Preface; due acknowledgement has been made in the text to all
other material used, and, the thesis is fewer than 100 000 words in length, exclusive of
tables, maps, bibliographies and appendices.

Ashley Greenwood
August 2016

page | 5

Preface
IN accordance with university requirements I would like to preface this thesis by
acknowledging that Sections 5 and 6 were completed with support and advice provided by
co-authors whose contributions are consistent with the work being original and my own as
declared in the Contribution to Published Work Forms section below.
Specific material contributions were made by Dr Gerrit Schoups who provided the Matlab
version of the generalised likelihood that I translated into R; and Dr Eddy Campbell who
provided an example of an adaptive Metropolis algorithm which I modified and
incorporated into my own code used in Section 6.
AJBG
August 2016

page | 7

Contribution to Published Work Forms

page | 9