Groundwater dependent ecosystems of the Barossa Prescribed Water Resources Area (Stage 1) Final Report November 2011 Groundwater dependent ecosystems of the Barossa Prescribed Water Resources Area (Stage 1) Barossa GDE Assessment (Stage 1) FINAL November 2011 Sinclair Knight Merz ABN 37 001 024 095 Level 5, 33 King William Street Adelaide SA 5000 Australia PO Box 8291 Station Arcade SA 5000 Australia Tel: +61 8 8424 3800 Fax: +61 8 8424 3810 Web: www.skmconsulting.com COPYRIGHT: The concepts and information contained in this document are the property of Sinclair Knight Merz Pty Ltd. Use or copying of this document in whole or in part without the written permission of Sinclair Knight Merz constitutes an infringement of copyright. LIMITATION: This report has been prepared on behalf of and for the exclusive use of Sinclair Knight Merz Pty Ltd’s Client, and is subject to and issued in connection with the provisions of the agreement between Sinclair Knight Merz and its Client. Sinclair Knight Merz accepts no liability or responsibility whatsoever for or in respect of any use of or reliance upon this report by any third party. The SKM logo trade mark is a registered trade mark of Sinclair Knight Merz Pty Ltd. Executive Summary This study has undertaken a broad regional assessment of potential GDEs in the Barossa PWRA. A desktop analysis of geomorphology, groundwater and ecology was used to define several GDE types, which may be considered to have common biophysical settings based on their particular combination of attributes. This method allowed for potential GDEs to be identified and an output of this process was the development of an inventory of potential GDEs for the study area (Table 7‐2). The potential GDEs identified were assigned an overall priority rating based on a combination of their ecological value, groundwater dependence and the threat posed by groundwater extraction. The process enabled potential GDEs to be prioritised as low, moderate or of high significance. For the Barossa PWRA, the following potential GDEs were identified as being high priority: The headwaters of the North Para River in Flaxman Valley The Barossa Valley Floor For the ongoing management and assessment activities of GDEs in relation to the water allocation process, the following activities are recommended: An ecological site assessment of potential GDEs to review the GDE typology and prioritisation described in this report, and to inform the derivation of EWRs. A catchment‐wide assessment of surface water – groundwater interactions to more accurately determine the location, nature and magnitude of groundwater discharge to streamflow. The current mapping products and assessments do not accurately characterise these interactions. Scoping the potential to develop a groundwater model for use in scenario testing. Expansion of monitoring network near high priority GDEs to monitor the groundwater regime, the surface water regime and the ecological condition. SINCLAIR KNIGHT MERZ I:\VESA\Projects\VE23576\Deliverables\Reports\Barossa GDE Assessment Stage 1 FINAL v5.docx PAGE i Contents 1. Introduction 2 1.1. Background 2 1.2. Scope 2 2. Overview of GDEs 5 3. Methodology 7 3.1. Overview 7 3.2. Characterisation and identification of GDEs 8 3.3. GDE Prioritisation 9 4. Study Area 10 4.1. Location 10 4.2. Rainfall and surface drainage 10 4.3. Landscape and soils 11 4.4. Ecological Assets 11 4.5. Hydrogeology 19 4.6. Groundwater use 21 5. Existing information on GDEs 25 6. Existing Information on Surface Water Dependent Ecosystems 27 6.1. Identified surface water dependent ecosystems 27 6.2. Primary Research 27 6.2.1. Environmental Water Requirements 27 6.2.2. Surface Water Budget and Farm Dams 31 6.2.3. Watercourse Priority Setting Project 31 6.2.4. Current Research 34 6.3. Information Gaps 34 7. Characterisation and identification of GDEs 35 7.1. Methodology 35 7.2. Classification of GDEs 38 7.3. Ecosystems dependent on the surface expression of groundwater (Type 2) 40 7.3.1. Fractured rock discharge and baseflow (FRD) 40 7.3.2. Groundwater discharge in valleys (GDV) 41 7.4. Ecosystems dependent on subsurface presence of groundwater (Type 3) 41 SINCLAIR KNIGHT MERZ I:\VESA\Projects\VE23576\Deliverables\Reports\Barossa GDE Assessment Stage 1 FINAL v5.docx PAGE ii 7.4.1. Break of slope GDEs (BoS) 41 7.4.2. Terrestrial vegetation on plains (TVP) 42 8. Prioritisation of GDEs 44 8.1. Introduction 44 8.2. Ecological value 44 8.3. Groundwater dependency 45 8.3.1. Ecological components indicative of wet environments 45 8.3.2. Significance of groundwater as a water input 47 8.4. Threats 49 8.5. Other threats relating to potential GDEs 53 8.6. Prioritisation 53 9. Groundwater dependency of downstream hydraulically-connected areas 55 9.1. Introduction 55 9.2. Previous Research 55 9.3. Hydrogeology 55 9.4. Ecology 56 9.5. Groundwater Extraction 56 9.6. Information Gaps & Recommendations 57 10. Recommendations to set EWRs and EWPs 58 11. Conclusions and recommendations 63 12. References 64 SINCLAIR KNIGHT MERZ I:\VESA\Projects\VE23576\Deliverables\Reports\Barossa GDE Assessment Stage 1 FINAL v5.docx PAGE iii Document history and status Revision Date issued Reviewed by Approved by Date approved Revision type Draftv4 9/9/2011 S Richardson D Currie 9/9/2011 Draft for client Review D. Currie Final v5 24/11/2011 AMLR NRMB D. Currie 24/11/2011 Final for client issue WAPAC Distribution of copies Revision Copy no Quantity Issued to V4 electronic Grant Lomman, Adelaide and Mount Lofty Ranges NRM Board V5 electronic Grant Lomman, Adelaide and Mount Lofty Ranges NRM Board Printed: 25 November 2011 Last saved: 24 November 2011 07:23 PM I:\VESA\Projects\VE23576\Deliverables\Reports\Barossa GDE Assessment Stage 1 File name: FINAL v5.docx Author: Helen Braithwaite, Marion Santich Project manager: Dougal Currie Name of organisation: Adelaide and Mount Lofty Ranges NRM Board Name of project: Groundwater dependent ecosystems of the Barossa PWRA (Stage 1) Name of document: Groundwater dependent ecosystems of the Barossa PWRA (Stage 1) Document version: Final Project number: VE23576 SINCLAIR KNIGHT MERZ I:\VESA\Projects\VE23576\Deliverables\Reports\Barossa GDE Assessment Stage 1 FINAL v5.docx PAGE 1 1. Introduction 1.1. Background The Barossa Prescribed Water Resources Area (PWRA) is centred approximately 60 km northeast of Adelaide and includes the prescription of wells, watercourses and surface water within the PWRA (Figure 1.1). The groundwater resources (extraction from wells) of the Barossa Valley floor were first prescribed in July 1989, followed by the watercourses of the North Para River and its tributaries in May 1992. The prescription of surface water within these catchments occurred in December 1998 and the PWRA boundary was extended to include the Greenock catchment area in May 2005. The current Barossa Prescribed Water Resources Area Water Allocation Plan was adopted by the Minister for Environment on 18 June 2009 and replaces the Barossa Water Allocation Plan dated December 2000. Water allocation planning is required under current legislation to take into account the water requirements of the environment and to make environmental water provisions for dependent ecosystems. The WAP acknowledges that there are significant knowledge gaps regarding groundwater dependent ecosystems (GDEs) in the PWRA by comparison to surface water dependent ecosystems. There is uncertainty surrounding the identification, the level and nature of their dependency to groundwater, their ecological value and the threat posed by groundwater extraction. This information is required to support the future determination of environmental water requirements and provisions to be implemented in the next WAP. Given the current knowledge gaps, SKM was engaged by the Adelaide and Mount Lofty Ranges Natural Resources Management Board (the Board) to provide an initial regional assessment of GDEs across the Barossa PWRA. This assessment will underpin the future determination of environmental water requirements (EWRs) for GDEs. 1.2. Scope The primary purpose of the Stage 1 assessment is to develop a knowledge base of potential GDEs in the Barossa PWRA and outline any further works necessary to adequately account for water needs of GDEs within the WAP framework. The study represents a first step in the water allocation process: characterising GDEs and determining their whereabouts. More targeted studies can follow that evaluate the water requirements of these systems. The scope of work includes: Collate previous information to summarise where GDEs have been identified and what is known about their current water requirements; Undertake desktop analysis to identify and describe all potential GDEs; SINCLAIR KNIGHT MERZ I:\VESA\Projects\VE23576\Deliverables\Reports\Barossa GDE Assessment Stage 1 FINAL v5.docx PAGE 2 Conduct a risk‐based prioritisation of GDEs based on their ecological values, level of groundwater dependency and level of threat from groundwater extraction; Review the level of existing information and scope further works for downstream GDEs in areas hydraulically connected to the Barossa PWRA; Develop a management response framework for the WAP that is commensurate with the level of risk to GDEs; and In addition to the assessment of GDEs, the study will review the knowledge base for surface water dependent ecosystems to identify knowledge gaps and outline suggested further works related to their water requirements. Given the hydraulic connection between groundwater and many of the surface water dependent ecosystems, this review will be conducted prior to the GDE assessment. SINCLAIR KNIGHT MERZ I:\VESA\Projects\VE23576\Deliverables\Reports\Barossa GDE Assessment Stage 1 FINAL v5.docx PAGE 3 NURIOOTPA ! TANUNDA ! GAWLER ! ADELAIDE ! HAHNDORF ! MCLAREN VALE ! VICTOR HARBOR ! ! Localities McLaren Vale PWA Western Mount Lofty PWRA Major Highways Central Adelaide Plains PWA Barossa PWRA Adelaide & Mount Lofty NRM Region Northern Adelaide Plains PWA 0 9 18 A4 : 1:793,561 Kilometers ± Figure 1.1 - Location map GDA 1994 MDA Z54 August, 2011 Groundwater-dependent ecosystems of the Barossa PWRA - Stage 1 I:\VESA\Projects\VE23576\Technical\GIS\ 2.