Department of Primary Industries Published by Department of Primary Industries, 2003 Primary Industries Research Victoria Bendigo December 2003 Also published on Website: http://www.dpi.vic.gov.au/clpr Ó The State of Victoria, 2003 This publication is copyright. No part may be reproduced by any process except in accordance with the provisions of the Copyright Act 1968. Authorised by the Victorian Government, Midland Highway, Epsom. The National Library of Australia Cataloguing-in-Publication entry: Pillai, Mayavan Salinity research and investigation inventory for the Corangamite CMA. Bibliography. ISBN 1 74146 017 4 1. Salinity – Research – Victoria – Corangamite. 2. Groundwater – Research – Victoria – Corangamite. 3. Hydrogeology – Victoria – Corangamite. I. Primary Industries Research Victoria. II. Corangamite Catchment Management Authority. III. Title. (Series : CLPR research Report ; no. 32). 631.416099457 ISSN 1447-1043 CLPR Research Report Series: No. 32 This publication may be of assistance to you but the State of Victoria and its employees do not guarantee that the publication is without flaw of any kind or is wholly appropriate for your particular purposes and therefore disclaims all liability for any error, loss or other consequence which may arise from you relying on any information in this publication. Pillai M (2003) Salinity research and investigation inventory for the Corangamite CMA Summary This document is an inventory of the key outcomes and recommendations from salinity research and investigations relevant to the Corangamite Catchment Management Authority (CMA) region since the original salinity strategy, Restoring the Balance (Nicholson et al. 1992). It provides a gauge as to the extent of application of research outcomes and recommendations, and will assist as a benchmark in identifying the inadequacies of current knowledge, future needs and research priorities. In general the magnitude of hydro(geo)logical parameters and processes that influence the development of salinity is not well understood at the local or implementation level. Though the nature of the broad processes may be reasonably understood in many areas, these are underpinned by relatively simple conceptual models of surface and groundwater processes. The lack of detailed understanding is due to a lack of measured physical data in relation to geology, regolith, soils and groundwater. This is not a criticism that can be simply levelled at historic Corangamite salinity R&I program(s), but is an indicator of the complexity of catchment hydro(geo)logy of the region, and the level of effort that is actually required to gather and interpret the data at the sub-catchment or implementation level. In the Corangamite CMA region hydro(geo)logical complexity is particularly aided by the presence of: · a diversity of hydrogeological environments and landscapes · complex soil water, regolith and landform characteristics influencing groundwater movement · the presence of multi-layered and different scaled flow systems within a single landscape unit · interactions of groundwater flow systems and surface water systems. Despite the limitations and a lack of perceived progress in salinity R&I (in the Corangamite CMA region and generally), there have been important broad advancements in the understanding of processes leading to salinity since Restoring the Balance. These advancements, for example, include the recognition that: · many landscapes that are effectively saturated (with respect to their sub-surface) · significant lateral throughflow or waterlogging processes occur in addition to classical groundwater flow in hydrogeological systems · groundwater response is strongly climatically driven · surface hydrology is likely to be significant for buffering the development of land and water salinity. The above have tended to be concluded and generalised from site specific investigations. However, given the unique response of landscapes to an imposed hydrological regime, such generalisations need to be treated with some caution as they will not always apply. The types of research work that have delivered these outcomes since Restoring the Balance include: · Conceptual understanding of catchment hydrological processes responsible for waterlogging and salinity gained from limited hydrological properties measured in selected sub-catchments. · Conceptual and some numerical modelling describing groundwater-surface water interaction in and around Lake Corangamite and the shallow lakes and wetlands of the western basalt plains. · Analysis of the complex soil-water-geomorphic characteristics in varying hydrogeological and climatic environments in south-west Victoria. · Limited water balance modelling incorporating landscape vegetation scenarios. The direction of salinity research and investigation in the Corangamite CMA region has been steered by a range of influences since the original inception of Restoring the Balance. For instance, the hot spot approach to targeting of implementation and research is now superseded by an assets-based approach to targeting salinity investment, augmented by knowledge now bound in the groundwater flow systems (GFS) framework. Though there have been some attempts to structure the salinity research efforts in the past, as in the thrust of an all-of-water balance approach of the mid-1990s, these efforts have been hindered by limited resources, and, to some degree, by entrenched and uncoordinated institutional responses to research. An analysis of actions resulting from research and investigation (R&I) recommendations reveals that R&I has under-achieved if measured by the number of implemented actions. This may be because the i Department of Primary Industries research cannot be translated to where actions are required, doesn’t adequately resolve the issue in question, or is poorly communicated. However, there is an argument that if the questions to be answered were more specific or defined in the first instance, then the answers would be more meaningful to the land manager. Increased dialogue between researchers and land managers is essential for improved R&I outcomes. Nowadays R&I tends to occur in a large number of projects spread across a large range of providers, so there is a significant challenge for the Corangamite CMA and its research partners to effectively link and logically synthesise these works into a cohesive and accessible knowledge base. The Corangamite CMA Salinity Action Plan provides a blueprint for focusing R&I, so the challenge is to implement this in an effective and efficient manner. To support this end a number of initiatives are supported by this analysis: · The R&I strategy is overseen by formally chartered technical support group. · A strategy be developed to support a culture of ongoing peer review of salinity R&I. · A mechanism for R&I outputs/outcomes to be acknowledged reviewed and responded to upon their completion (feedback). · A knowledge management strategy with mechanisms for capture, retention and provision of knowledge and data. · Production of periodical statements of knowledge. · Appropriate resourcing and funding. In the context of the historical Corangamite CMA salinity R&I it is clear that some basic work remains unfinished. In the immediate-term there should be some consideration of pursuing this to completion. Work that could be advanced with good value for effort would include: · Comprehensively documenting the outcomes of the Simpson and Gerangamete agroforestry sites. · Documenting the effectiveness of monitoring of a range of salinity control treatments across the Corangamite CMA region. · Documenting the issues and arguments relating to the impacts of surface and sub-surface drainage on the catchment water balance ii Pillai M (2003) Salinity research and investigation inventory for the Corangamite CMA Contents Summary................................................................................................................................................. i Contents................................................................................................................................................iii Acknowledgements ............................................................................................................................. iv Abbreviations....................................................................................................................................... iv Abstract...................................................................................................................................................1 1 Introduction ...................................................................................................................................1 1.1 Background ....................................................................................................................................1 1.2 Purpose ...........................................................................................................................................1 1.3 Scope ...............................................................................................................................................2 1.4 Methodology ..................................................................................................................................2 2 Significant topics of research.......................................................................................................3 2.1 Groundwater-surface water interaction around