Environmental Flow Study Glenelg River System

Stressed rivers project - Environmental flow study

Glenelg River System Stressed rivers project - Environmental flows study

Glenelg River System

April 2003

Sinclair Knight Merz Pty Limited ACN 001 024 095 ABN 37 001 024 095 590 Orrong Road Armadale VIC 3143 PO Box 2500 Malvern VIC 3144 Australia Telephone: +61 3 9248 3100 Facsimile: +61 3 9248 3364

COPYRIGHT: The concepts and information contained in this document are the property of Glenelg Hopkins Catchment Management Authority. Use or copying of this document in whole or in part without the written permission of Glenelg Hopkins Catchment Management Authority constitutes an infringement of copyright. Contents

PART A

1. Introduction...... 1 1.1 Project scope ...... 1 2. Catchment description...... 2 2.1 Physiography ...... 2 2.2 Landuse ...... 6 2.3 Hydrology ...... 7 2.4 Water quality ...... 10 2.4.1 Salinity...... 10 2.4.2 Dissolved oxygen...... 11 2.4.3 Nutrients ...... 11 2.4.4 pH...... 11 2.4.5 Turbidity...... 11 2.5 Biota ...... 12 2.6 Summary...... 14 3. Key issues...... 16 3.1 Potential environmental issues ...... 16 3.2 Sand slugs ...... 19 3.3 Water quality ...... 20 3.4 Flow regulation...... 22 3.5 Channel condition ...... 24 3.6 Current flora and fauna values of the Glenelg River system ...... 25 3.7 The heritage reach...... 26 4. Methods...... 28 5. Site descriptions...... 31 6. Objectives...... 37 6.1 Policy and strategy objectives ...... 37 6.2 Catchment objectives ...... 38 6.3 Environmental objectives...... 38 7. Discussion...... 40 7.1 Seasonal timing of releases ...... 40 7.2 Periods of cease to flow ...... 41 7.3 Baseflows ...... 41 7.4 Freshes during periods of cease to flow/low flow ...... 41 7.5 Spring freshes...... 42 7.6 Flow variability...... 42 7.7 High flows ...... 42 8. Recommendations...... 43 8.1 Flow Recommendations ...... 44 8.1.1 Reach 1 – Rocklands Reservoir – Chetwynd River...... 44 8.1.2 Reach 2 – Chetwynd River to Wannon River ...... 52 8.1.3 Reach 3 – Wannon River to Tidal Extent ...... 61 8.2 Supporting recommendations ...... 67 9. References ...... 71

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE i PART B 1. Introduction...... 1 1.1 Project scope ...... 1 1.2 Report structure...... 2 2. Catchment description...... 3 2.1 Physiography ...... 3 2.2 Landuse ...... 3 2.3 Hydrology ...... 7 2.4 Water quality ...... 10 2.4.1 Salinity...... 10 2.4.2 Dissolved oxygen...... 11 2.4.3 Nutrients ...... 11 2.4.4 pH...... 11 2.4.5 Turbidity...... 12 2.5 Biota ...... 12 2.6 Summary...... 14 3. Key issues...... 16 3.1 Potential environmental issues ...... 16 3.2 Sand slugs ...... 19 3.3 Water quality ...... 20 3.4 Regulation ...... 22 3.5 Channel condition ...... 23 3.6 Current flora and fauna values of the Glenelg River system ...... 24 3.7 The heritage reach...... 25 4. Environmental objectives...... 27 4.1 Preliminary umbrella objectives...... 27 4.2 Preliminary specific objectives ...... 27 5. Outcomes...... 28 5.1 Assessment framework...... 28 5.1.1 Technical panel...... 28 5.1.2 Study reaches ...... 28 5.1.3 Use of existing data and information...... 30 5.2 Reporting...... 30 6. References ...... 31 Appendix A Hydrology...... 34 A.1 Streamflows...... 34 A.2 Licensed water use...... 36 A.3 System operation...... 37 A.4 Summary...... 38 A.5 Flow plots ...... 39 A.6 Flow duration curves...... 42 A.7 Rocklands Reservoir discharge ...... 54 Appendix B Geomorphology...... 55 B.1 Introduction ...... 55 B.2 Stream network...... 55 B.3 Hydrology ...... 56 B.4 Landuse ...... 56 B.5 Sand slugs ...... 57

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE ii B.6 Summary...... 58 Appendix C Water quality...... 59 C.1 Salinity...... 60 C.2 Nutrients ...... 61 C.3 pH...... 62 C.4 Dissolved oxygen...... 63 C.5 Turbidity...... 63 C.6 Summary...... 64 C.7 Water quality plots indicating guideline values ...... 65 Appendix D Biota 77 D.1 Condition of instream and riparian habitat...... 77 D.2 Fish, decapod crustacea and molluscs...... 77 D.2.1 Fish ...... 77 D.2.2 Decapod Crustacea ...... 82 D.2.3 Macroinvertebrates ...... 82 D.3 Birds ...... 83 D.4 Amphibians and reptiles ...... 83 D.5 Other vertebrates ...... 84 D.6 Instream and riparian flora...... 85 D.7 The Glenelg Heritage River and Lower Glenelg National Park...... 86

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE iii Document History and Status

Issue Rev. Issued To Qty Date Reviewed Approved Draft 1 Project Team 1 20/9/01 P. Close M. Shirley Draft 2 Alex Marshall GHCMA 1 24/9/01 M. Shirley M. Shirley Draft 3 Melanie Tranter 1 28/4/02 R Nathan R Nathan GHCMA Draft 4 Melanie Tranter 1 16/10/02 S Hannon M Shirley GHCMA Final 4 Melanie Tranter 1 23/1/03 R. Nathan R. Nathan GHCMA

Printed: 7 May, 2003 Last Saved: 7 May, 2003 File Name: \\SKM- MELB8\VOL1\DATA\PROJECT\Wcms\Wc01432\500_Analysis_Reporting\Reporting\Released Reports\Glenelg\R04_Mjs_Glenelg_Final.Doc Project Manager: Michael Shirley Name of Organisation: Glenelg Hopkins Catchment Management Authority Name of Project: Wimmera, Avoca and Glenelg Rivers Environmental Flows Name of Document: Glenelg River – Final Report Document Version: Final Project Number: WC01432

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE iv 1. Introduction

There is an increasing awareness in water resource management of the need to incorporate the environmental requirements of ecosystems into the water resource planning process. Alteration to flow regimes can have significant impacts on riverine aquatic ecosystems. Under the 1994 Council of Australian Governments (COAG) agreement, the environment is recognised as a legitimate water user and environmental water requirements must be assessed and provided. As a result the determination of the water regime required to sustain the physical and ecological processes of aquatic ecosystems is a key process.

The Victorian Water for the Environment Program, implemented by Department of Sustainability and Environment, aims to implement measures that provide water for environmental needs. The objective of the program is to increase environmental flows to maintain and, where possible, restore the environmental values of rivers and wetlands, whilst recognising existing entitlements.

The Glenelg River was examined by the Scientific Panel as part of the Stressed Rivers assessment of priority rivers for the development of restoration plans. The Stressed Rivers Scientific Panel noted that the effect of Rocklands Reservoir was likely to have caused a decline in the health of the aquatic ecosystems of the Glenelg River. It was not specified as a high priority river because at the time it was considered that the system, with Rocklands Reservoir in its current operational condition, did not include capacity to deliver the water required for further environmental enhancement (Stressed Rivers Scientific Panel, 1998). Recent developments to increase the extent of the Wimmera-Mallee Pipeline mean that there may be additional water made available to meet the environmental needs of the Glenelg River.

1.1 Project scope A range of flow related issues have prompted this study to determine environmental water requirements of the Glenelg River.

The current project examines the environmental water requirements of the surface water systems of the main stem of the Glenelg River, excluding the Wannon River and the estuarine ecosystem.

The aim of this project is to provide a scientific basis for the implementation of provisions for water dependent ecosystems, and in doing so, meet the objective of the State's Water for the Environment Program and objectives of the Glenelg Hopkins Catchment Management Authority. The staff of the Catchment Management Authority and the members of the Project Group made a significant contribution to the project and the outcomes, and we thank them for this input.

The project includes a clear scientific process for the determination of environmental water requirements and recommendations to maximise the implementation of these provisions.

This report is the final report of the project. It includes a synopsis of the key issues in the Glenelg River system, environmental flow objectives, detailed environmental flow recommendations and key supporting recommendations. The Appendices of the report provide the detailed assessment of the flow related issues for the system.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 1 2. Catchment description

The study area specified for this report is the main channel of the Glenelg River. No tributaries are included in the study area.

2.1 Physiography The Glenelg River rises in the Grampians and flows to the Southern Ocean (Figure 2-1 Glenelg River catchment). On leaving the Grampians the river flows along the northern and then the western edge of the Dundas Tablelands, between Rocklands Reservoir and Casterton. Near Casterton the Wannon River joins the Glenelg River and from there the Glenelg River meanders across broad coastal plains towards Dartmoor. Below Dartmoor the river follows a generally southerly course becoming increasingly incised in limestone (Erskine 1994). At the confluence of Moleside Creek the river turns west north west and runs parallel to the coast before flowing south into South Australia, then back south south east to enter the sea at Nelson, Victoria.

The catchment is approximately 120 km wide and 100 km from north to south, covering a total area of 1,266,030 ha (Department of Water Resources Victoria 1989). The topography of the catchment varies substantially from the rugged escarpments of the Grampians in the northeast to the coastal plains in the southwest. The Victoria and Serra Ranges of the Grampians drain into both the Glenelg and the Wannon Rivers; the former drains the north and west of the catchment and the latter the east and south. The central portion of the catchment is composed of the deeply dissected Dundas and Merino tablelands. Towards the southeast the tablelands drop down to the flat basal plains around Hamilton. Near Nelson there is an estuarine lagoon at the mouth of the Glenelg River and a line of calcareous sand dunes fringes the coastline. During low flow conditions salt water penetrates upstream beyond the boundary of the Lower Glenelg National Park. At over 70 km, the Glenelg estuary is one of the State’s longest (Sherwood et al. 1998).

In 1986, the Department of Water Resources conducted a survey of the environmental condition of Victorian streams. Within the Glenelg River catchment the condition or health of 58 sites located on both the Glenelg River and its tributaries was described using both biological and physical assessment criteria (Mitchell 1990). In general, approximately 45% of the Glenelg River and 70% of tributaries within the catchment were described as poor to very poor environmental condition. In 1994 seven of the original 58 sites were resurveyed. While some sites had improved as a result of exclusion of stock from riparian zones, stream condition was still described as generally poor (Davidson et al. 1994).

Davidson et al. (1994) suggested that flow regulation, sedimentation, salinisation and extensive snag removal were the main factors leading to poor channel condition. Our field observations support those of Mitchell et al. (1996) that the riparian vegetation is continuous to discontinuous along both banks of the river but is generally restricted to the bankface and the immediate bank verge (Figure 2-2, Figure 2-3). The lower section in the Lower Glenelg National Park is in good condition with excellent bank and verge vegetation (Figure 2-6). The banks are generally stable with only isolated examples of bank erosion (Figure 2-4). In some locations, bank instability is associated with stock traffic.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 2 The main issue associated with physical condition of the Glenelg River is the high sand load that occupies a large proportion of the channel (Figure 2-5). The sediment has created a sandy bed and reduced the occurrence of deep holes (>2m) in sections of the river. Areas of sediment build-up are most obvious are around Casterton and Harrow.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 3 n Figure 2-1 Glenelg River catchment.

WC01432:R04_MJS_GLENELG_FINAL.DOC Draft PAGE 4 n Figure 2-2 Glenelg River at Fulham Hole Streamside Reserve (note typical riparian vegetation, consisting of patchy overstorey and little or no understorey).

n Figure 2-3 Glenelg River at Dartmoor.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 5 2.2 Landuse The Department of Water Resources Victoria (1989) reports that European settlement of the Glenelg catchment began in 1837. The merino wool industry was established quickly and today wool is still the main product of the region with prime lamb production also important. The beef industry is well established and a small amount of dairying occurs in the catchment. Since 1837, two-thirds of the catchment has been cleared for pasture to graze sheep and cattle and today only two main forested areas remain. The northeast of the catchment is forested and includes the Grampians National Park, as well as State Forest where a small amount of hardwood is logged. In the west there is a mixture of native hardwood forests (the Glenelg National Park) and intensive softwood plantations. In addition to the intensive forested areas there are occasional extensive blue gum plantations found in the catchment (Department of Water Resources Victoria 1989). Hamilton is the major urban centre within the catchment, located in the southeast.

n Figure 2-4 Glenelg River at Wannon River confluence (note erosion of left bank).

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 6 n Figure 2-5 Sand slug in the Glenelg River downstream of Chetwynd River confluence.

2.3 Hydrology Rainfall varies seasonally and spatially within the catchment. While winter months are wetter throughout the catchment, there is a gradual decline in mean annual rainfall from the coast near Nelson (approximately 750 mm) to the centre of the catchment (approximately 550 mm). In the northeast of the catchment, in the vicinity of the Grampians, annual rainfall increases with elevation to more than 900 mm on the Victoria Range. Rainfall is relatively reliable along the coast and in the higher parts of the Grampians (Department of Water Resources Victoria, 1989).

Reflecting rainfall distribution, flows are strongly seasonal with 70% of average annual flow in the Glenelg River above the Wannon River junction occurring in the three months August to October. At Dartmoor (Station 238206), the residual mean annual flow of the Glenelg River, post Rocklands Reservoir construction, is 639,000 ML. Although only 1.5 % of that total occurs in the months January to March, there are reliable base flows rarely falling below 30 ML per day during this period (Department of Water Resources Victoria 1989).

Wimmera Mallee Water (WMW) and Southern Rural Water Authority (SRW) both have jurisdiction over water flow in the Glenelg River. The Glenelg River upstream of Mooree Bridge is the responsibility of WMW, while downstream of Moree Bridge is the responsibility of SRW.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 7 n Figure 2-6 Lower Glenelg River

There are three notable water storages within the Glenelg River basin. These are Konong Wootong Reservoir, Moora Moora Reservoir and Rocklands Reservoir. Konong Wootong is a small reservoir constructed on Den Hills Creek, a tributary of the Wannon River, to supply the townships of Casterton and Coleraine. The capacity of this storage is 1,920 ML and diverts approximately 852 ML/year out of the system (Ingeme 1996). Moora Moora Reservoir is located in the upper reaches of the Glenelg River. The reservoir is a small, offstream storage with a capacity of only 6,300 ML (Department of Water Resources Victoria 1989). Lake Bellfield diverts water from the upper Wannon River. Rocklands Reservoir is the largest storage in the catchment with a total capacity of 348,000 ML. The primary purpose of the storage is to provide domestic and stock supply to the Wimmera Mallee Water channel system (Godoy 1996).

Rocklands Reservoir has a significant impact on the seasonal flow pattern downstream of the reservoir, although the impact decreases with distance from the dam. Rocklands has a storage capacity about three times its average annual inflow and has spilled once every four years on average since construction. Downstream of the Chetwynd River, flows are continuous due to natural inflow from the catchment adding to the river flows. However, in December 2000, the Glenelg River ceased flowing below Casterton (M. Tranter pers. comm.). Current releases from Rocklands Reservoir do not appear to exert an influence below Casterton due to the limited availability of water for release (Mitchell et al. 1996). Rather streamflow at Casterton is influenced by inflow from other sources including tributaries and rainfall near Casterton.

The Glenelg River, under natural conditions, commonly ceased to flow at Balmoral over the three months February to April, sometimes for months longer (Godoy 1996).

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 8 The deep pools through the river would have allowed the key biota to persist during the cease to flow periods. However, the cease to flow does not occur within the current flow regime, which is a summer autumn flow release. Under low flow conditions transit times for releases from Rocklands Reservoir are approximately 7 days to Balmoral, 14 days to Fulham Bridge and 21 days to Harrow. According to Mitchell et al. (1996) a 20-25 ML/day release at Rocklands delivers 10 ML/day at Fulham Bridge and 2 ML/day at Harrow.

The total licensed volume for water extraction from the main channel of the Glenelg River is 68.2 ML/year which is a very small proportion of licensed water entitlement in the Glenelg River system. All licences on the Glenelg River extract upstream of the Wannon River confluence (J Donovan, pers. comm.). An additional 878.6 ML/year is licensed for extraction from the remainder of the catchment. Of the 68.2 ML/year available for extraction from the Glenelg River, 66 ML/year is extracted through two irrigation licences. These licences are generally used sometime between September and February, although the specific timing of such use is dependent on the crops being irrigated. The remaining 2.2 ML/year is a dairy licence, which is used throughout the year for dairy washing and stock watering.

Further information on the licensed entitlement within the Glenelg River system is presented in Appendix A. The licensed volume is distinct from the total volume that is actually extracted each year due to a number of factors including the availability of flow and water quality.

The Rocklands Outlet channel passes from Rocklands Reservoir in the Glenelg River Basin to Toolondo Reservoir in the Wimmera Catchment. Water is also lost from the Glenelg River due to evaporation at Frasers Swamp and tributary plugs restrict the rate of inflow into the Glenelg River mainstem. In addition, losses due to seepage from the river can lead to lower streamflows. To reduce losses along the river to Fulham Bridge, Wimmera Mallee Water can release water from the 5 and 12 Mile channel outfalls, although this is generally only done when there are concurrent transfers to Toolondo Reservoir. There is some leakage from the Rocklands Outlet channel that reaches the Glenelg River and helps offset some of the losses in this reach.

A compensation flow from Rocklands Reservoir down the Glenelg River is currently fixed at 3,300 ML/year. This was previously a sliding scale between 2,500 ML and 3,700 ML/year, but at the request of the Glenelg Hopkins CMA, a new formula has been developed being the average of the historic releases, (3,300 ML/year; Table 2-1) (R Leeson, pers. comm.). Wimmera Mallee Water is required to maintain a reserve volume in Rocklands to guarantee this compensation flow. The compensation flows, released in summer and autumn, are aimed to maintain a target flow of 5-10 ML/d at Fulham Bridge and 1-2 ML/day at Harrow. Commencement of compensation flows is timed to take advantage of the wet river channel and thus prevent the flow from ceasing altogether (Godoy 1996) and the releases to the river are based on the flow measured at Fulham Bridge (Gauge 238224). The compensation flows are generally released between mid November to late April, depending on the weather.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 9 n Table 2-1 Summary of environmental flow releases for the Glenelg River (Source Wimmera Mallee Water) Season Compensation Flow Environmental Flow Total Release ML ML ML 1996-97 3,700 4,119 7,819 1997-98 3,210 6,167 9,377 1998-99 3,300 5,736 9,036 1999-2000 3,300 1,994 5,294

2.4 Water quality The key parameters that influence ecological processes and water use are salinity, nutrients (TN and TP), pH, dissolved oxygen (DO), and turbidity (SKM 2001a).

2.4.1 Salinity Salinity varies along the length of the Glenelg River and depends on the structure of the channel and groundwater intrusions. The section of the Glenelg River between Rocklands Reservoir and Fulham Bridge was characterised by Sherwood et al. (1998) as shallow sections (<3 m deep) interspersed with deep elongated pools (>8.5 m deep). This section of the river has been identified as a major source of salt. Salinity increases with distance downstream from Rocklands Reservoir through this reach (Sherwood et al. 1998).

McGuckin et al. (1991) also documented salinity in the 15 km section downstream of Rocklands Reservoir. They found surface and bottom salinities were between 3,500 mS/cm and 7000 mS/cm with surface salinities approximately 2000 mS/cm less than that at the bottom. Further downstream, conductivity declined to approximately 2000 mS/cm with the exception of Fulham Bridge, where bottom conductivity was 10,380 mS/cm. In the reach between Casterton and Dartmoor, McGuckin et al. (1991) found no significant difference in surface and bottom salinities.

Deoxygenation also prevailed in the section of the river between Rocklands Reservoir and Fulham Bridge with the lowest concentrations of dissolved oxygen coinciding with high bottom conductivities (McGuckin et al. 1991). Adverse temperature was also closely associated with saline pools in this reach. The persistence of such conditions greatly affects the amount of suitable available habitat for aquatic organisms. If the deeper areas of the pool habitats are highly deoxygenated it may cause a significant reduction in useable habitat, and also reduce access to the benthos which is a significant source of food and resources. Although stratification and deoxygenation would have occurred naturally in pools, particularly in low flow events, the current reduced flow conditions exacerbate this effect.

At times of low flow, saline groundwater is a major source of salt (Glenelg Regional Catchment Strategy, 1997). At higher flows, fresh surface water masks the effect of groundwater (Sherwood et al. 1998). A decrease in salinity that occurs between Myaring Bridge to Dartmoor, approximately 20 km downstream, is likely to be due to dilution that results from inflow of less saline surface or groundwater. The change in catchment dynamics, as a result of the impact of Rocklands and Moora Moora Reservoirs, has exacerbated the salinity effects because of the reduction in winter freshes in the system.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 10 2.4.2 Dissolved oxygen Severe deoxygenation has been found throughout the length of the Glenelg River (McGuckin et al. 1991). McGuckin et al. found that deoxygenation was closely associated with the presence of saline pools in the reach from Rocklands Reservoir to Fulham Bridge with each pool registering a bottom dissolved oxygen concentration of less than 10% saturation. Sites between Casterton and Dartmoor were only slightly better than upstream with values ranging between 10-40% saturation. McGuckin et al. suggested that the temperature gradient in this section of the river was most likely associated with the depth of the pool and was the governing factor controlling DO at conductivities less than 500 mS/cm.

Although low dissolved oxygen does not appear to be of concern at the VWQMN sampling sites, isolated locations do exhibit low DO concentrations. Of particular concern is the significant reduction in DO at depth in the deep pools along the Glenelg River, especially in the reach from Rocklands Reservoir to Fulham Bridge. Low levels of DO also occur at depth in the estuarine section of the river.

2.4.3 Nutrients Nutrient enrichment of the waterways within the catchment has also been recognised as a significant issue. To date there have been no blue green algal blooms reported in the Glenelg River although eutrophication of the farm dams and lakes has been recorded (Dixon et al. 1998). Blooms have, however been recorded in Rocklands Reservoir in 1991.

Sources of nutrients within the Glenelg River are varied. For example, contrary to the norm, active erosion in the subcatchment of Sandford contributes to total nitrogen (TN) loads but no total phosphorus (TP). Nitrogen may be from decaying organic material and animal wastes. Until 1996/97, the Casterton Wastewater Treatment Plant was contributing an unknown load of nutrients to the river, which would be having a major impact. This practice of discharging has now ceased (Wagg 1997). Septic tank effluent at Dartmoor may also contribute to nitrogen concentrations in the river (Sherwood et al. 1998). At Dartmoor, total Kheldahl nitrogen associated with organic material is also positively related to flow, similarly for TP, which is attached to sediments (Wagg 1997).

Although TP rarely exceeds the guideline values (SKM 2001a) in the Glenelg River, values of TN progressively exceed the ANZECC guideline values for the river with distance downstream. The occurrence of high nitrogen values can potentially lead to the growth of algal blooms.

2.4.4 pH With few exceptions, monitored values of pH within the catchment over the past decade have been within guidelines. Median pH values have only been outside the two guidelines at Big Cord where water was slightly acidic. This indicates that pH is not an issue in terms of water quality in the Glenelg River below Rocklands Reservoir.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 11 high flow during winter (Department of Water Resources Victoria 1989). Turbidity at Fulham Bridge has been shown to correlate positively with discharge at flows greater than 10 ML/day (Mitchell et al. 1996). Turbidity is not of concern in the Glenelg River system as the high winter turbidity levels are not prolonged and return to acceptable levels.

2.5 Biota The native freshwater fauna of the Glenelg River system represent a diverse assemblage with high conservation significance. Twenty species of native freshwater fish and 26 estuarine species have been recorded from the Glenelg River system (SKM 2001a, DNRE 2000c). Eight species have conservation significance and of these, five are protected through their listing on the Victorian Flora and Fauna Guarantee Act 1988. Four species are protected through their listing on the List of Threatened Australian Vertebrate Fauna (ANZECC 2000). Of the 20 species of native freshwater fish, seven are known to migrate between freshwater and estuarine/marine habitats at some stage in their life cycle (Koehn and O’Connor 1990). Seven species of decapod crustacea and at least three species of bivalve mollusc have also been recorded (SKM 2001a). Of these, the Glenelg freshwater mussel (Hyridella glenelgensis) and the western swamp cray (Gramastacus insolitus) are suspected of being rare, with restricted distributions and low abundances (Tarmo Raadik pers. comm.). Consequently, these species may in the near future be rated as highly threatened fauna in Victoria. The EPA (1999) recorded a total of 86 families of macroinvertebrates from a total of 61 survey sites throughout the Glenelg River catchment (SKM 2001a). Mitchell et al. (1996) and EPA (1999) report a dominance of insects (such as beetles, mayflies and true bugs) in the macroinvertebrate community, as is commonly the case in fresh waters. Based on the macroinvertebrate communities present, the health of sites in the Glenelg River was assessed as good to excellent in both pools and shallow habitats based on ratings presented in OCE (1988). Increased community complexity and abundance of macroinvertebrates was reported at sites with macrophytes and organic debris (Mitchell et al. 1996). There have been 271 species of bird recorded along the Glenelg River of which 50 species have conservation significance either in Victoria or nationally (DNRE 2000a, DNRE 2000b). Of the threatened species, 20 are reliant directly upon the instream environment for their survival (SKM 2001a). The warty bell frog (Litoria raniformis), has been recorded in the Glenelg catchment and is listed as vulnerable by DNRE (2000b). Two species of threatened reptile, the swamp skink (Egernia coventryi) and tree goanna (Varanus varius), have been recorded from the Glenelg catchment (DNRE 2000a). Although the tree goanna does not directly depend on the riparian environment, such areas often provide the only remaining habitat. It should be noted that the latest recorded sightings of these species date from the early 1980’s. Other vertebrates present in the catchment and known to depend directly on the instream environment for food and shelter include the platypus (Ornithorhynchus anatinus) and water rat (Hydromys chrysogaster). Platypus have been recorded in the Glenelg River near Casterton and Dartmoor and in the vicinity of Fulham Hole at 5

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 12 Mile Channel Outfall. The species has also been recorded in the Wannon River near Coleraine and Hamilton, Mackinnon Creek and Grange Burn (unpublished database Australian Platypus Conservancy; Melanie Tranter pers. comm.). The water rat has been observed in south west Victoria and was observed during the field work for this project. Locations of recorded sightings are listed in the Atlas of Victorian Wildlife (DNRE, 2000a). The Long-footed Mouse eared Bat (Myotis adversus) is also found in the catchment. They are known to take insects from the water surface and consequently would directly and indirectly benefit from the provision of environmental flows.

Of the 63 threatened flora species that occur in the Glenelg River catchment (SKM 2001a), 15 of them rely directly on the instream environment or temporary inundation for their survival (DNRE, 2000; Dale Tonkinson pers. comm.). Thirty species of aquatic and semi-terrestrial macrophyte have been recorded in the mid to upper reaches of the Glenelg River (Mitchell 1996). Species richness within sites ranged from 7-11. Emergent aquatic macrophyte species were dominant and represent between 67 and 100% of species present at sites surveyed.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 13 2.6 Summary n Table 2-2 Summary of environmental issues, reach by reach. Reach Geomorphology Flora and Fauna Water Quality Hydrology Headwaters to backwater Low flows and sediment deposition in mid to of Rocklands Reservoir upper reaches of Glenelg have been shown to promote excessive growth of Typha spp. and Phragmites australis

Rocklands Reservoir to Sediment buildup around Low flows and sediment deposition in mid to Salinity increases with distance downstream 70% of annual flow occurs Aug to Oct Chetwynd River Harrow upper reaches of Glenelg have been from this reach to Wannon shown to promote excessive growth of Regulation of Rocklands Typha spp. and Phragmites australis For a distance 15km downstream of Significant impact on streamflows Reservoir is inpart Rocklands salinity varies greatly caused by Rocklands and spills responsible for the low Rocklands Dam significantly impedes between the surface and bottom of the only once every four years transport rate upstream movement of migratory fish river. species. Glenelg R used to dry at Balmoral Feb 60% loss of capacity due to Very low Dissolved oxygen and temperature to Apr under natural conditions sand slugs at Harrow A large proportion of high and moderate value is associated with saline pools for the but current conditions do not and Burkes Bridge with only one sub-reach requiring above distance lead to drying rehabilitation Water lost due to evaporation at Fraser’s Swamp

There is a significant reduction in peak flows, due to Rocklands Reservoir, down to Casterton

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 14 Reach Geomorphology Flora and Fauna Water Quality Hydrology Chetwynd River to Sediment buildup around Platypus recorded near Casterton Erosion in the Sandford subcatchment 70% of annual flow occurs Aug to Oct Wannon River Casterton contributes to increased nitrogen loads to Wannon Variegated pygmy perch endemic to Glenelg 20% loss of capacity due to catchment and found in reach between Deoxygenated pools present Continuous streamflow due to natural sand slugs at Harrow and Strathdownie inflows Casterton A large proportion of this reach is comprised There is a significant reduction in peak of moderate value sub-reaches with a flows, due to Rocklands similar number but smaller length of Reservoir, down to Casterton high value sub-reaches. Two small sub- reaches requiring rehabilitation occur in this region

Wannon River to tidal 10% loss of capacity due to Lower Glenelg National Park in good High nitrogen due to septic inflows No licences for extraction in this reach extent sand slugs at Dartmoor condition with excellent bank and verge vegetation Deoxygenated pools present

Platypus recorded near Dartmoor

This reach contains a larger proportion of high value than moderate value sub- reaches. There are not any sub-reaches requiring rehabilitation in this reach

Tidal extent to river mouth No licences for extraction in this reach

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 15 3. Key issues

In common with other river basins around Australia, the hydrology of the Glenelg River catchment has undergone substantial change in the past 200 years. Extensive clearing of native vegetation for agriculture and the introduction of rabbits has resulted in a number of primary impacts on the Glenelg River such as salinisation, erosion and sedimentation. These modifications to the channel system have been further exacerbated as a result of system regulation by Rocklands Reservoir and water harvesting.

3.1 Potential environmental issues Rocklands Reservoir in the upper Glenelg River catchment has reduced the mean annual flow downstream of the dam from 113,000 ML/year naturally to 42,700 ML/year currently (data from this study). The dam also has the capacity to affect major floods and medium flows, and whilst it has not had pronounced effects on low flows in most months it has decreased winter and spring floods and high summer flows (Mitchell 1996). Rocklands Reservoir also presents a barrier to the movement of migratory fish species and localised movement of non-migratory species. Furthermore, the mitigation of major floods may have implications for connectivity between the main channel of the Glenelg River and its floodplain.

Mitchell et al. (1996) suggests that the altered flow regime in the mid to upper Glenelg River may not have affected the spawning of endemic native fish in this region as the spawning cycles of these species do not appear to be cued to flooding. Nevertheless, flushes in late summer/early spring may be important for improving water quality after low flow periods. This inturn may affect the recruitment success of native fish species by influencing the survival of juvenile fish.

Primary impacts on the Glenelg River such as salinisation, erosion and sedimentation are, to varying degrees, a result of extensive clearing of native vegetation for agriculture (Mitchell 1996). Riparian vegetation is particularly important to in-stream biota as it provides shading, food (terrestrial invertebrates) and shelter (leaf litter, woody debris). Riparian vegetation also influences water chemistry through filtering and buffering the in-stream environment from allocthanous sources of sediment, chemicals and nutrients. In the Glenelg River catchment, clearing of vegetation has resulted in gully and sheet erosion that delivers sediment to the upper river. Moreover, removal of riparian vegetation in mid to lower reaches of the river has resulted in bank instability and subsequent bank slumping which has contributed to sedimentation and reduced capacity of the channel. These processes reduce instream habitat complexity, an essential requirement for aquatic fauna in that it provides different microhabitats for shelter, spawning, food production etc.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 16 q river regulation leading to a reduction in the magnitude, frequency and duration of high flows in winter and spring thus diminishing channel flushing (removal of sediment from channel) q desnagging leading to a direct loss of woody substrates.

Many of these factors are interrelated and are affected by flow but not alone attributable to the altered flow regime. For example, extensive sedimentation in the Glenelg River (some reaches of stream have lost 80% of their former channel capacity) has occurred as a result of vegetation clearing, introduction of rabbits and erosion. Nevertheless, diminished flows over the winter/spring period result in a lack of flushing of the river channel thus leaving sediment deposited in pools in the upper and mid reaches of the Glenelg River

The loss of aquatic macrophytes, salinisation, sedimentation, smothering and removal of snags and altered flow regimes have direct and indirect impacts on instream fauna (macroinvertebrates, fish, reptiles and amphibians, and other vertebrates). Aquatic vegetation and woody debris are an important component of habitat complexity in deeper reaches of rivers (Walker et al. 1992) and are often correlated with macroinvertebrate species (O’Connor 1991 in Mitchell et al 1996) and fish species richness (Schlosser 1982). Decreases in the diversity and abundance of aquatic macrophytes and the loss of snags lead to a loss of food source, spawning sites and shelter for both aquatic macroinvertebrates and fish.

Salinisation as a result of native vegetation clearing and elevated groundwater levels is a primary environmental issue in the Glenelg River (Mitchell 1996). Salinisation and subsequent stratification occur in deep pools (>2 m) in the Glenelg River. In pools over 3 m deep, stratification is stable, long-lived and reappears 1-2 months after flushing (Mitchell 1996). Conductivity in the Glenelg River is highest during the low flow period between January and March and shows a second increase in June-July attributable to additional salt inputs from “first flush” events (Mitchell 1996). Reduction in the magnitude of natural flows as a result of Rocklands Reservoir may also contribute to salinisation of downstream sites. Saline groundwater intrusion appears to be most pronounced above Fulham Bridge (Cameron and Jekabsons 1992, McGuckin et al. 1991, Mitchell 1996) and results in stable stratification under low to moderate flow conditions.

Salinisation may influence flora and fauna directly or indirectly through a variety of complex mechanisms. For example, salinisation may affect organisms indirectly through creating changes to habitat attributes (i.e. a direct effect on macrophytes which are important as cover for some fish species) or trophic relationships between species. Salinisation also leads to stratification and subsequent deoxygenation of the water below the halocline, this in turn may preclude fish and macroinvertebrates from important refuge habitats in pools. These indirect effects are complex and have been summarised well by Mitchell (1996).

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 17 While the following section considers each of the identified issues as separate phenomena, they are in reality all interlinked. Moreover, their relative importance changes with location within the catchment and through the year. Due to the interaction between issues it is impossible to legitimately rank them relative to each other. Hence, the order in which the issues are described is not one of relative importance within the catchment.

In brief, the five key issues that confront the Glenelg River are as follows. 1. Sand slugs: q loss of channel form; q reduced substrate diversity; and q reduced instream habitat diversity.

2. Water quality: q salinisation; q stratification and subsequent deoxygenation of water column; q reduction in habitat availability for aquatic fauna; and q inhibition of aquatic macrophyte growth.

3. Flow regulation: q altered flood frequency, magnitude, duration; q changed flow seasonality; and q diminished channel flushing.

4. Channel condition: q bank erosion; q stock access; q riparian clearing; and q desnagging.

5. Current values of the Glenelg River: q riparian and instream flora present; and q aquatic fauna community.

6. Heritage river reach: q high environmental value; and

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 18 q degraded riparian zone outside National Park.

3.2 Sand slugs Sand accumulation in stream channels is a major stream management issue in the Glenelg River catchment. Gully, sheet and rill erosion of granite portions of the catchment have filled the Glenelg and its tributaries with about 6,000,000 m3 of sand (Rutherfurd and Budahazy, 1996). Little sand is now coming from the catchment, so the major source of sand to the Glenelg River is the lower reaches of tributary streams. The tributaries introduce discrete slugs of sand to the main channel that often partially dam the river, these slugs are commonly referred to as tributary junction plugs. As these sand slugs move downstream they attenuate, gradually giving way to a succession of small sluglettes. Rutherfurd and Budahazy (1996) estimate the sand slugs are moving through the stream network at a slow rate, with only tens of thousands of cubic metres being removed by bedload transport. The low transport rate is due, in part, to regulation of the river from Rocklands Reservoir.

Rutherfurd and Budahazy estimate that there are 4 – 8 Mm3 of sand stored in the Glenelg River and its tributaries. Channel storage estimates range from about 50,000 m3/km in the Glenelg at Harrow, to an average of about 10 – 20,000 m3/km elsewhere in the system. The sand occupies a larger proportion of the cross-section in the tributaries (up to 80%) than in the Glenelg River. Capacity loss (loss of channel capacity) in the Glenelg River falls from about 60% between Harrow and Burkes Bridge, to 20% at Casterton, and 10% at Dartmoor.

Most of the sand was deposited in the lower reaches of the streams very quickly after the onset of channel extension through gullying. However, the original deep pools in the Glenelg River, combined with regulation from Rocklands Reservoir, have limited the movement of sand through the trunk stream. Of the sand already stored in the main channel, only about two-thirds will be available for downstream transport. About one-third will be more permanently stored in benches, pointbars or on the floodplain. Rutherfurd and Budahazy cite several lines of evidence that suggest bedload transport rates are in the order of 10-30,000 m3/year.

The main source of sand for the main channel is now located in the lower few kilometres of tributary streams. Importantly, in smaller tributaries, large volumes of sand are stored in deep areas of the bed that have been abandoned by widening of the channel. In Bryans Creek and Pigeon Ponds Creek, this bed storage has removed up to half of the total volume of sand available for transport (Rutherfurd and Budahazy, 1996).

A major flood could move large volumes of sand, as occurred in the 1946 flood when large volumes of sand were deposited in the channel and on the floodplain. However, regulation has dramatically reduced the frequency of large floods, particularly close to Rocklands Reservoir, and consequently the rate of sand transport (Ian Rutherfurd, pers. comm.; Brizga et al., 2000). The sand is now moving through the stream network in a complicated pattern, but it will take many decades for the sand to be stabilised and removed.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 19 because of the decreased roughness associated with sand sheets. In addition, deposition on the floodplain has meant that in many reaches the rise in bed level has been matched by an increase in bank height.

A complicating factor in managing sand in the Glenelg River is the form of channel adjustment that takes place once the sand is removed from a reach. Both Rutherfurd and Budahazy (1996) and Brizga et al. (2000) report examples of bed incision and consequent bank erosion following sand extraction from the channel. Bed incision of the main trunk can also lead to incision of the tributaries, particularly if those tributaries are graded to the elevation of the sand surface.

The sediment influx has smothered the previous channel form and dramatically simplified the geomorphological diversity of the channel by creating a sandy bed with less deep holes. Loss of geomorphological diversity in turn restricts habitat availability. Typically in rivers the greatest diversity of macroinvertebrates and fish are found where there is an abundance of large woody debris (LWD), water plants or cobbles and rocks. The effect of sand and silt is to fill crevices and bury potential aquatic habitat. Where sand slugs do not totally bury LWD or completely smother coarser substrates there is little evidence that species diversity or stream environmental values are significantly reduced (Brizga et al., 2000).

Brizga et al. (2000) found that in fact there were very few areas where sand comprised the only available habitat. While many pools may have partially filled with sand there is still a remnant sequence of pools and shallow areas usually with some residual LWD. However, the loss of deep holes in the river has removed sites of refuge for platypus during periods of low flow. Furthermore, artificially reduced flows during low flow periods may have implications for the movement of platypus between pools and foraging behaviour, thus restricting platypus to regions of poor water quality. Low flows and sediment deposition in the mid to upper Glenelg River have also been found to promote excessive growth of Typha spp. and Phragmites australis in the river channel (Mitchell et al. 1996). This consequently impedes flows and leads to further sediment deposition and further reduction in habitat complexity.

The accumulation and slow movement of sand has led to a general decrease in habitat availability and diversity. The provision of environmental flows will only go a small way to moving the sand to alter this impact. There will not be a substantial increase in habitat area in response to environmental flows, but there will be a relative increase in the quality of habitat. Environmental flows will maximise the habitat available considering the current levels of sand and habitat change in the river.

Overall the flow changes have resulted in reduced sediment transport through the system which has had major implications for structural habitat change within the channel. These structural habitat changes, in the form of sand slugs and isolation of pools, have had significant resultant effects on other components of the ecosystem such as water quality and community continuity.

3.3 Water quality The analyses, described in Appendix C, indicate that the water quality in the Glenelg River system is poor with respect to salinity. Salinity is particularly high in pools in the reach of the Glenelg River between Rocklands Reservoir and Fulham Bridge (Cameron and Jekabsons 1992, McGuckin et al. 1991, Mitchell et al. 1996). Although

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 20 turbidity and nutrients are generally not as high, historical levels have been, at times, high enough to adversely impact the aquatic biota.

Salinisation is most likely to influence flora and fauna directly or indirectly through a variety of complex mechanisms. For example, salinisation may affect organisms indirectly through creating changes to habitat attributes (i.e. a direct effect on macrophytes which are important as cover for some fish species) or trophic relationships between species. Salinisation also leads to stratification and subsequent deoxygenation of the water below the halocline, this in turn may preclude fish and macroinvertebrates from important refuge habitats in pools. These indirect effects are complex and have been summarised well by Mitchell et al. (1996).

Salinisation and subsequent stratification occur in deep pools (>2 m) in the Glenelg River. In pools >3 m deep, stratification is stable, long-lived and reappears 1-2 months after flushing (Mitchell et al. 1996). Salinity in the Glenelg River is highest during the low flow period between January and March and shows a second increase in June-July attributable to additional salt inputs from “first flush” events from tributary inflows (Mitchell et al. 1996). Reduction in the magnitude of natural flows as a result of Rocklands Reservoir may also contribute to salinisation of downstream sites.

There is currently an environmental flow allocation of 34,690 ML for sharing between the Wimmera and Glenelg Catchments. Such flows have not been realised because of drought conditions in recent years. This allocation is planned to increase with further stages of pipelining of the Wimmera Mallee Water system. The current releases differ from environmental flow recommendations as they are designed to sustain the ecosystem, rather than return all or part of the natural flow regime. However, these flows are not always delivered in their entirety. Deakin University is undertaking a biological monitoring program in the Glenelg River to determine if the environmental allocations have had a significant beneficial effect. Over the four seasons since 1994/95 when the monitoring began, there have effectively been two years when the allocation was delivered to approximately 20-25% of allocated flows and two years when it was 70-80% of recommended flows (B. Mitchell, pers. comm.). The reduction in flows delivered were due to periods of drought and subsequent water limitations.

The Deakin University monitoring program has not reported yet but preliminary data analysis suggests that when close to the 80% of the environmental allocation is provided in a given year there is a positive response in water quality parameters, particularly dissolved oxygen and salinity levels (B. Mitchell, pers. comm.). In years when the proportion of environmental allocations has been closer to 25% of allocated flows, there still remains a positive effect, although the improvement in water quality is reduced. For example, even the relatively low environmental allocations delivered in 1996/97 of 4,119 ML had a positive impact on water quality.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 21 not be managed using flushing (Mitchell et al. 1996). Mitchell et al. (1996) recommend sustaining environmental flows in the summer-autumn period to compensate for lost habitat with an additional provision for spring flows. The low level sustaining flows would also help manage the water quality within the surface water of the pools and the preliminary indications are that these flows are having a beneficial effect on the surface water quality (B. Mitchell pers. comm.) In the long term large flushing flows are important for managing the stream channel form and movement of sediment. These flows would also act as important disturbances to the biological community.

Direct effects of salinisation may result if salt tolerances of organisms are exceeded, leading to lethal physiological effects. Similarly, increased levels of salt may have sub-lethal effects on stream biota that may result in reduced growth rates, reduce reproductive success and reduced health and vigour. For example, Mitchell et al. (1996) suggest that the range of the Glenelg spiny crayfish, severely restricted by habitat degradation in the Glenelg River basin, is also under threat from saline water. Glenelg spiny crayfish moult frequently when small, but by 50 mm occipital length moulting is restricted to once a year between January to May. At this time water quality in the modified upper river is poor with elevated temperature and salinity, and reduced oxygen levels. When a crayfish moults its ability to osmoregulate is reduced, consequently high salinities may reduce growth or survival (Mitchell et al. 1996). Mitchell et al. (1996) also noted that a conspicuous feature of macrophyte communities was the absence of submerged aquatic macrophyte species in downstream sites. It was suggested that salinities in pools at the downstream sites might be sufficiently high to affect the growth of submerged macrophytes.

The salinity levels within the Glenelg River system may potentially affect a range of biota. It is considered for example, that fish are a good indicator of the effect of salinity on a river system because they are mobile and their occurrence may reflect the health of a river reach (Ryan and Davies 1996). Some fish species found in the Glenelg River, for example the Common Galaxias (Galaxias maculatus), are relatively tolerant of salinity because of their migratory stages and may not be greatly affected by current salinity levels (Pollard 1971). Other species found in the Glenelg River, such as the River Blackfish (Gadopsis marmoratus), are relatively sensitive to saline conditions, particularly in juvenile life stages (Ryan and Davies 1996). Salinity levels found within the Glenelg River would also impact a range of invertebrate species, resulting in a reduction in diversity and abundance (Hart 1982).

Consequently the impacts of salinity may be two-fold, direct effects on biotic health and structural effects reducing useable habitat within the system.

3.4 Flow regulation Rocklands Reservoir has diverted water from the upper Glenelg River catchment to the Wimmera River system since 1953. Using the flow data for the Glenelg River, developed in the current project, the average mean annual flow has reduced from 113,000 ML/year naturally to 42,700 ML/year currently. These figures clearly indicate that as a result of the diversion the natural flow regime of the Glenelg River has been substantially altered and is missing several critical flow elements. Firstly, the overall volumes of water are greatly reduced throughout the year and large flushing flows are absent. These changes exacerbate sand slug formation, saline pools and reduction in structural diversity. The mitigation of major floods also has

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 22 implications for connectivity between the main channel of the Glenelg River and its floodplain.

As shown by the estimated natural and current flow duration curves presented in Appendix A, streamflows upstream of Rocklands Reservoir have not changed substantially. However, immediately below Rocklands Reservoir seasonality of flow has been reversed by regulation. Immediately downstream of Rocklands Reservoir, under natural conditions, median flows peak during August at 23,400 ML/month and lowest flows occur during the summer months, particularly February. Current flows are now less than natural flows for the majority of the year. Zero flows occur during the months May to November, inclusive. Moreover, peak flows at this site occur during December to February, inclusive. During June and July, zero flow prevails 100% of the time under current conditions. Between August and October, flow exceeds 0 ML/month for less than 18% of the time under current conditions, while under natural conditions, flow exceeded 700 ML/month.

The effect of regulation is obviously greatest immediately downstream of Rocklands Reservoir, although effects continue a significant distance downstream. The reduction in peak flows is highly significant all the way through to Casterton, downstream of the confluence with the Wannon the impact of peak flows is still apparent (e.g. at Dartmoor) although is relatively reduced. As discussed these peaks flows are important for sand and sediment movement through the system. They also are considered to be key trigger flows for a number of biological events such as fish spawning and invertebrate recruitment. Consequently, reduction in timing, recurrence, duration and magnitude of peak flow events has a significant effect on both the biological and physical processes in the river.

The natural periods of cease to flow that may have previously occurred have been discussed previously. In addition the low flow conditions have also been significantly altered. For example, between Rocklands outlet and Casterton the low flows over the winter period are significantly reduced. This means that during winter the flow between peak flow events is generally lower. This could reduce areas of spawning habitat and general habitat diversity at key periods for the aquatic community.

The Glenelg River system is considered self regulatory by Southern Rural Water. Southern Rural Water has not previously had a formal water restriction policy in place due to flow rapidly dropping to zero as water levels begin to fall during the summer months and water quality also declines. Ad hoc restrictions were imposed in the summer of 1998/99, during which river flow of 10 ML/day was used as a trigger to implement restrictions. Such restrictions were unnecessary due to the river rapidly dropping to zero flow once it was below 10 ML/day and the water becoming too saline for agricultural use. Therefore, the timing of bans coincided with conditions that were unsuitable for pumping due to lack of water and high salt levels. Similarly, restrictions were imposed on the Wannon last summer (1999/00) but due to the flow dropping very quickly by mid January such restrictions were once again unnecessary. Southern Rural Water also used 10 ML/day, an arbitrary figure, to impose restrictions on the Crawford River and the Grange Burn (J Donovan, pers. comm.).

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 23 may have adversely impacted fish communities through eliminating other flow related cues. Flushes in late summer/early spring may be important for improving water quality after low flow periods. This, in turn, may affect the recruitment success of native fish species by influencing the survival of juvenile fish.

3.5 Channel condition A number of reports discuss the degraded condition of the Glenelg River (e.g. Rutherfurd and Budahazy 1996; Brizga et al. 2000; Erskine 1994). Each of these have identified similar themes of degradation: q catchment sheet and gully erosion; q sand slugs; q sand extraction; q macrophyte loss; q localised bed and bank erosion; q riparian degradation (including unmanaged stock access); q desnagging; and q river regulation.

Schreiber et al. (1998) also assessed the environmental aquatic habitat of the Glenelg River based on bed composition, proportion of pools and riffles, bank vegetation, degree of cover for fish and the extent of sedimentation or erosion. Their rating ranged from moderate to very poor.

The loss of aquatic macrophytes, salinisation, sedimentation, smothering and removal of snags and altered flow regimes have direct and indirect impacts on instream fauna (macroinvertebrates, fish, reptiles and amphibians, and other vertebrates). Aquatic vegetation and LWD are an important component of habitat complexity in deeper reaches of rivers (Walker et al. 1992) and are often correlated with macroinvertebrate species (O’Connor 1991 in Mitchell et al 1996) and fish species richness (Schlosser 1982).

Large woody debris plays a critical role in providing stable substrate and hydraulic diversity in sand-bed streams, and is arguably even more important in sand-bed streams than other types of streams (Brizga et al. 2000). There has been significant desnagging within the Glenelg River system, specifically the reach in the Casterton region. Decreases in the diversity and abundance of aquatic macrophytes and the loss of LWD lead to a loss of food source, spawning sites and shelter for both aquatic macroinvertebrates and fish. However, the available data on macroinvertebrate populations in the river is equivocal. For example based on the macroinvertebrate the communities present Glenelg River was assessed as good to excellent in both pools and shallow habitats (OCE 1988). Whereas as part of the National River Health Strategy the Glenelg River Catchment was described as highly degraded (Schreiber et al. 1998). (See Appendix D for more detail).

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 24 Riparian vegetation is particularly important to in-stream biota as it provides shading, food (terrestrial invertebrates) and shelter (leaf litter, woody debris). Riparian vegetation also influences water chemistry through filtering and buffering the instream environment from allocthanous sources of sediment, chemicals and nutrients. In the Glenelg River catchment, clearing of vegetation has resulted in gully and sheet erosion that delivers sediment to the upper river. Moreover, removal of riparian vegetation in mid to lower reaches of the river has resulted in bank instability and subsequent bank slumping which has contributed to sedimentation and reduced capacity of the channel. Loss of riparian vegetation reduces shading for the stream channel and has a consequent effect on water temperature also. These processes reduce instream habitat complexity, an essential requirement for aquatic fauna in that it provides different microhabitats for shelter, spawning, food production etc.

3.6 Current flora and fauna values of the Glenelg River system The native freshwater flora and fauna of the Glenelg River system represent a diverse assemblage with many species of high conservation significance. This in turn is a key issue for the system as it means that there are key species of recognised conservation value many of which are under threat due to flow related changes within the Glenelg River. There is a resultant increased potential for response by the ecosystem to improvements in the flow regime as the system is not devoid of desirable species. Consequently changes in the flow regime, or parts thereof, may be more likely to have a beneficial ecosystem response.

Some examples of the flora and fauna of value include: q Eight fish species have conservation significance and of these, five species are protected through their listing on the Victorian Flora and Fauna Guarantee Act 1988. Of these, four species are protected through their listing on the (ANZECC 2000) List of Threatened Australian Vertebrate Fauna. q There are 50 species of birds that have conservation significance either in Victoria or nationally (DNRE 2000a, DNRE 2000b) and of the threatened species, 20 are reliant directly upon the instream environment for their survival. q One species of threatened amphibian, the warty bell frog (Litoria raniformis), has been recorded from the Glenelg catchment. The conservation status of this species is vulnerable (DNRE 2000b). q There are two species of threatened reptile, the swamp skink (Egernia coventryi) and tree goanna (Varanus varius), in the Glenelg catchment (DNRE 2000a). The conservation status of the swamp skink is vulnerable that of the tree goanna is data deficient (DNRE 2000b). q The platypus (Ornithorhynchus anatinus), although not of documented conservation significance, have been recorded in the Glenelg River near Casterton and Dartmoor and in the vicinity of Fulham Hole. The platypus is a significant ‘icon species’ in Australian aquatic systems and considered of considerable values by the community.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 25 q There are 63 threatened flora species in the Glenelg River catchment, 15 of which are dependant on the aquatic environment (DNRE, 2000; Dale Tonkinson DNRE pers. comm., 2000).

In addition to the listed flora and fauna of the Glenelg River system there are numerous other species of value to the region and community.

3.7 The heritage reach The lower section of the Glenelg River, from Nelson on the coast to Dartmoor, is designated a “Heritage River” under the Heritage Rivers Act 1992 (DNRE 1997) and is listed as a Nationally Important Wetland by Environment Australia. The Heritage River corridor covers an area of approximately 3020 Ha and is about 50 m wide for most of its length. The lower section of the Heritage River flows through the Lower Glenelg National Park. The Heritage River corridor provides an important habitat link particularly between inland woodlands and the coast for species reliant on riparian habitats. This habitat corridor is well protected within the National Park although public land water frontages are degraded at Nelson, Donovan’s and below Dartmoor (DNRE 1997).

There are several key values associated with the heritage river reach. q Thirteen rare or threatened flora species are known to occur in the heritage river corridor although many of these are only known from local knowledge (DNRE 1997). Rare Bog Gum and the Lime Fern are two examples. Additionally, the leafy greenhood and the limestone spider-orchid are listed under the Flora and Fauna Guarantee Act 1988. q Twenty three significant fauna species in the Heritage River Corridor. Of these species 11 are listed in the Flora and Fauna Guarantee Act 1988. q A diverse fish fauna in both freshwater and estuarine sections, including five significant fish species. q The lower Glenelg River karst area – an area of limestone between Keegan's Bend and Nelson – is of state significance (LCC 1991). Extensive caves in the area provide habitat for several significant species of bat. q The only Victorian estuary developed in dune calcarenite ridges (Bird 1977). q Remnant River Red Gum community south of Dartmoor (DNRE 1997). q Moleside Creek (tributary of the Glenelg River) contains numerous species of fern. q Numerous recreational values – fishing, boating, camping, walking (DNRE 1997).

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 26 q undertake research and monitoring of significant fish species and environments, monitor sand and silt effects on the River including the sand slug upstream the Heritage River corridor (DNRE 1997).

Flow related threats to the lower Glenelg River might include the encroachment of the upstream sand slug and the alteration of late summer/autumn and winter/spring flow events. Rutherfurd and Budhazy (1996) suggest that the sand slug may not reach the Heritage River for approximately 30-40 years. Nevertheless, the impacts of the sand slug are likely to be similar to those that have occurred in the mid to upper reaches of the Glenelg River (e.g. infilling of deep pools, smothering of substrates, etc) ultimately leading to decreased habitat complexity. With regards to the alteration of flows to the lower Glenelg River, this has not been quantified and hence it is difficult to determine the potential biological impacts.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 27 4. Methods

This project was completed concurrently with the Stressed Rivers Project that developed a new method for the determination of environmental water requirements for use within Victoria. The overall justification for the methodology and the detail of the method is covered in a separate report. The overall methodology of this project incorporated components as they were developed. The outline of the methodology is shown in Figure 4-1.

Project Inception

Data Collation

Issues Paper

EFTP Hydrology Fieldwork

Surveying

Hydraulic Modeling

Analysis

Project Group Final Report

n Figure 4-1 Outline of the project methodology The initial stage of the project involved a compilation of the set of issues relevant to the catchment and production of two issues papers (Sinclair Knight Merz, 2001). The subsequent stages of the project involved more detailed investigation at specific sites determined to be representative of the key issues within the catchment. Descriptions of the sites are included in subsequent sections, the sites were selected to represent a range of hydrological, ecological and geomorphological features.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 28 The sites were assessed using a technical panel with relevant ecological and geomorphological expertise. For this project the technical panel comprised Michael Shirley (Project Manager and ecologist), Paul Close (Ecologist), Brenton Zampatti (Ecologist), Tanya Wansbrough (Geomorphologist) and Bruce Abernethy (Geomorphologist).

At each site visited a series of standard descriptive tasks were undertaken. During this stage, the locations of cross-sections at each site were identified for subsequent surveying. Between six and nine cross sections were pegged at each site using a single peg located on one bank. From this point the channel shape was surveyed perpendicular to the flow. These cross sections were selected to be representative of site features in areas of key habitats as identified across the relevant disciplines.

Following the pegging of all cross sections, each cross section was drawn and flow bands identified. The cross sections were drawn to identify key features of ecological or structural relevance within the section. These were then correlated to the surveyed cross-sections to allow accurate determination of the ecological flow bands.

At each site a series of flow bands or flow components were identified that are specific for that particular reach of the river. The flow bands are components of the flow regime that are considered structurally or ecologically important for the ecosystem. These bands were described hydrologically as well as the specific ecosystem function that they fill.

All cross sections identified at the sites were surveyed for channel shape, using a total station. The survey was conducted to indicate any significant changes in channel shape, stream flows and habitat structure. All cross sections within a site were then linked to each other to indicate the slope and meanders of the river at that site. Water level was recorded at all sites to assist in validation of the hydraulic model.

A hydraulic model was prepared to develop a relationship between stream flow, and water level and velocity for each site. The hydraulic analysis of the sites was undertaken using the HEC-RAS software, which is designed to perform one- dimensional steady state calculations for a full network of natural and constructed channels or a single river reach. Separate hydraulic models were constructed for each of the sites using the surveyed cross sections. These models were then validated over a range of flows from minor to bankfull discharges.

Each model was then validated by undertaking a sensitivity analysis of the channel roughness represented by Manning’s ‘n’ values and by adjusting the downstream boundary condition. As there was little or no data available for calibration it will be necessary to assign textbook Manning’s ‘n’ values for channel roughness. Appropriate values were then selected based on photographs and the site visit.

Additionally, a sensitivity analysis was undertaken by adjusting Manning’s ‘n’. Model outputs showed the variation in total depth for the range of Manning’s values tested. The sensitivity of the model to the downstream condition was also assessed to determine the impact on calculated results. The most appropriate downstream boundary conditions were then determined by plotting each of the water surface profiles and identifying the most realistic hydraulic gradient.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 29 A range of flows were routed through the model, these flows represented the full range of flows up to bankfull.

A daily flow series was generated for each site through a separate project. At some sites where there were no local gauges, flow data was transposed from existing gauge data to provide the flow series for each site. A ‘natural’ and ‘current’ flow series was determined where the natural flow series removed all known extractions under the current landuse.

The hydrological assessment involved consideration of a range of hydrological parameters to describe the flow regime, including: q flow duration curves to examine the percentage of time that a flow of a given size is exceeded; q time series graphs to examine the sequence of flow events, particularly during very dry or very wet conditions; and q Get Spells analysis to describe flow spells (flow events over a defined threshold).

Key flow indicators were extracted from this information, such as mean and median flow, and suitable high and low flow indices such as the flow exceeded 20% and 80% of the time.

A series of fish surveys were conducted to assess the distribution of key fish species through the catchment and the relationship with flow and groundwater flows. The outcomes of these surveys have been incorporated into the recommendations developed.

The analysis of the outputs and development of the recommendations was done by the technical panel. The implications of changed flow regimes were examined based on the specified flow bands for each site. Recommendations have been developed that describe the entire flow regime, not solely a minimum flow over a defined period.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 30 5. Site descriptions

Site 1 – Five Mile Site 1 is located on the Glenelg River approximately 500 m downstream from the confluence of the Five Mile Channel Outfall. This reach is characterised by a deep pool upstream (>2 m deep), a glide/run section with a mid-channel island, mid-reach and an anastomosing section downstream. The anastomosing reach is comprised of two primary channels, one of which was flowing on our inspection, and the other wetted with no flow. A number of secondary channels also dissect the floodplain. Streambank sediments are mainly sandy loams whilst the streambed is dominated by sands and silt.

The floodplain vegetation community is open grassy woodland with a Box (Eucalyptus spp.) and River Red Gum (E. camaldulensis) overstorey and native/exotic grass understorey which is generally in poor condition. Similarly, the riparian zone is highly disturbed and comprises relatively sparse stands (~50% cover) of River Red Gum with an understorey of native/exotic grasses with some native shrubs – predominantly Tea-Tree (Leptospermum sp.) and Paperbark (Melaleuca sp.). Instream vegetation is relatively diverse although restricted mostly to the margins of deep pools. Aquatic vegetation includes Common Reed (Phragmites australis), Water Ribbons (Triglochin sp.), Stonewort (Nitella sp.) and submerged grasses.

Instream habitat is reasonably diverse and includes aquatic vegetation (5%), large woody debris (15%), organic debris (branch piles, leaves and bark 20%) and small areas of undercut bank. Disturbances to the instream channel include stock access, exotic fish (Gambusia and possibly Carp) and some siltation of instream habitats by fine sediment.

n Figure 5-1 Site photos from Five Mile Channel Outfall.

Site 2 – Pine Hut Hole This site is characterised by a deep pool upstream (>2 m deep) and an anastomosing reach downstream. The anastomosing reach comprises several channels that were flowing on the day of our inspection and a number of other secondary channels that were dry. The streambed and banks are comprised of fine sands and sandy loams.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 31 The floodplain is in relatively good condition and vegetated by an open grassy woodland community with River Red Gum overstorey and native/exotic grass and sedge understorey. There is also some eucalypt regeneration in the understorey. The riparian zone exhibits similar floral characteristics with River Red Gum dominating the overstorey. The understorey comprises native/exotic grasses, Common Reed, Paperbark and Cumbungi.

Instream vegetation is relatively diverse. In the pool, aquatic vegetation is dominated by stands of Common Reed, Spike Rush (Eleocharis sphacelata ), Cumbungi and Tassled Sedge (Carex fascicularis). A diversity of aquatic plant species are also established in open water areas in the anastomosing section of the reach downstream of the pool. In this section, Common Reed, Cumbungi,Water Ribbons, Elodea (Elodea sp.), Ribbon Weed (Vallisneria gigantea) and Pond Weed (Potamogeton sp.) are wide spread and abundant.

Instream habitat varies substantially between the pool and anastomosing sections of the survey reach. The pool comprises mostly open water habitats (85% wetted area of reach) with stands of aquatic vegetation and some large woody debris along the stream margin. In the anastomosing section, aquatic vegetation (30%), large woody debris (5%) and organic debris (leaves, branch pile and bark 10%) dominate the habitat attributes. Disturbances to the instream channel include stock access and exotic fish (Gambusia and possibly Carp).

n Figure 5-2 Site photos from Pine Hut Hole.

Site 3 – Upstream of Harrow This site was located upstream of the road crossing on private property (Dick Roberts) upstream of Harrow township. The reach is characterised by a diversity of hydraulic habitats including pool, run, riffle and glide. Adjacent hillslopes confine the channel, with only narrow, discontinuous alluvial flats developed on the stream margins (<20 m wide). Deposits of coarse sand dominate the bed (75%) with small areas of gravel (20%) and overlying silt (5%).

The riparian vegetation community is open woodland with River Red Gum overstorey, with some Melaleuca and Casuarina species. The understorey consists of native shrubs and a mixture of native and exotic grasses. There is a diversity of aquatic vegetation present within the reach including Common Rush (Juncus usitatus), Water Ribbons, Cumbungi (Typha sp.) and filamentous algae. Instream habitat is dominated

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 32 (55%) by emergent aquatic vegetation (Common Reed and Cumbungi) with small areas of overhanging vegetation, coarse substrate and organic debris.

The most obvious instream disturbance was deposition of sand and smothering of aquatic habitats. Channel constriction through partial revegetation of large sandbars by Common Reed, Cumbungi and Paperbark is also evident and alters the natural hydraulic characteristic of the reach. Tributaries and springs near the reach were noticeably salty. Other instream disturbances included exotic fish (Gambusia) and areas of bank instability (due to stock access) and rabbits.

n Figure 5-3 Site photos from upstream of Harrow.

Site 4 – Burkes Bridge Site 4 is located immediately upstream of Burkes Bridge on the Edenhope-Casterton Road. The channel is confined by hillslopes on its right side. The floodplain (>500 m wide) formed on the left side of the channel has some shallow secondary channels and billabongs which were dry during the field inspection. The channel has been extensively filled with sand that forms large point bars and braided channel characteristics in some areas.

Floodplain and riparian vegetation communities are open woodland with an overstorey of River Red Gum and an understorey of wattles (Acacia spp.), bracken and native/exotic grasses and herbs. The riparian zone supports additional wetland species including Common Reed, Common Rush and Tea-Tree. Instream vegetation is generally sparse with the exception of the Common Reed, which forms dense stands along the right hand stream margin. Only small areas of Common Rush and Ribbon Weed were present within the reach.

The most obvious instream disturbance was deposition of sand and smothering of aquatic habitats. Channel constriction through partial revegetation of large sand bars by Common Reed and Common Rush is also evident and alters the natural hydraulic characteristic of the reach. Tributaries and springs in the vicinity of the reach were noticeably salty. Other instream disturbances included exotic fish (Gambusia), a road crossing and weeds.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 33 n Figure 5-4 Site photos from Burkes Bridge.

Site 5 – Roseneath Site 5 was located approximately 200 m upstream of the bridge on Warrock Road at Roseneath. This reach is characterised by riffle and pool hydraulics, active erosion of the channel, unstable bed and banks (mass failures on outer banks) and a high load of LWD. At the surveyed site, the channel bifurcates around a large vegetated island. The channel is confined by hill slopes on its left side. A floodplain (>500 m wide) exists on the right bank. Stream bank sediments are sandy loams whilst the streambed is dominated by actively mobile sands.

The floodplain vegetation has been predominantly cleared and replaced with exotic pasture grasses. The riparian zone exhibits similar floral characteristics. Isolated River Red Gum woodland are present on both banks including some regeneration on the left bank. Instream vegetation is sparse and includes Common Reed and Water Ribbons.

Instream habitat is dominated by LWD (70% wetted area) with small areas of aquatic vegetation, organic debris and rock habitat. The most obvious disturbances are stock access, active erosion, sand accumulation and riparian clearing. Other instream disturbances included exotic fish (Gambusia and possibly Carp) and weeds.

n Figure 5-5 Site photos from Roseneath.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 34 Site 6 – Section Road Site 6 is situated approximately 150 m downstream from Section Road in a reach of the river that meanders across a broad floodplain. At this site, the instream habitat has been totally smothered by sand, leaving a wide and shallow flowing reach. Stream substrate is dominated by deposits of fine sand (75%), coarse sand (5%) and small areas of gravel (20%).

The floodplain vegetation comprises predominantly cleared eucalypt woodland that has been replaced with exotic pasture grasses. Similarly the riparian zone is highly disturbed and comprises cleared eucalypt woodland although some regeneration is occurring. Instream vegetation is in relatively poor condition and dominated by emergent species such as Common Reed and Cumbungi. Instream cover is very sparse and comprises only small amounts of aquatic vegetation (2%) and logs (2%). The accumulation of sand has reduced structural habitat complexity. Other disturbances are stock access and riparian zone degradation.

n Figure 5-6 Site photos from Section Road.

Site 7 – Bahgallah Road Site 7 is located approximately 150 m downstream of the Bahgallah Road bridge. The stream is deeply incised (up to 10 m) with steep, unstable banks formed in sandy loams. The channel is some 50 m wide with a flat bed of sand. On the day of our inspection, low flow meandered within the channel bed.

The floodplain vegetation comprises only pasture grasses and generally is in poor condition. The riparian zone is also disturbed and comprises remnant River Red Gum woodland and an understorey of exotic grasses. Instream vegetation is in relatively poor condition and comprises Water Ribbons, Common Reed and algae. Instream habitat is dominated by algae (65%). Apart from the broad sand sheet that fills part of the streambed, other instream disturbances include exotic fish (Gambusia), bank instability (due to increasing height and steepness from bed degradation), a gauging weir and a bridge.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 35 n Figure 5-7 Site photos from Bahgallah Road.

Site 8 – Dartmoor This site is located within a stream side reserve upstream of Greenham Road near Dartmoor. The reach is characterised by a diversity of hydraulic habitats including pool, run, riffle and glide. Streambanks are formed in silty loams whilst the streambed is dominated by actively mobile sands.

The riparian zone comprises River Red Gum woodland with an understorey dominated by exotic groundcover species. Regeneration of River Red Gum and acacias is evident. Instream vegetation is in good condition and comprises predominantly submerged species including Water Ribbons, filamentous algae and Elodea. Instream habitat is reasonably diverse and includes aquatic vegetation (50%), large woody debris (8%) and organic debris (branch piles, leaves and bark 2%). Actively mobile sands have formed bars on the inside bends and benches on both banks. Other disturbances include weed infestation, vehicle tracks and litter.

n Figure 5-8 Site photos from Dartmoor.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 36 6. Objectives

The objectives for this study are described in a structure that allows for specific detail in each reach. The overarching objectives are the regional objectives, these are relevant at a National, State and regional level. A series of strategies, Acts and policies are listed that are relevant at each level. The environmental flow recommendations have been developed and should be implemented within the context set by these overall objectives. Where appropriate specific components may be referenced in the supporting recommendations.

6.1 Policy and strategy objectives National

q Council of Australian Governments Water Reform Agenda

The Federal and State Governments in the Council of Australian Governments’ (COAG) Water Reform Agenda have recognised the need to reform the water resource industry and provide water for the environment. The 1994 COAG agreement recognises the environment as a legitimate water user and environmental water requirements must be assessed and provided. This agreement is a key driver for studies such as this current study.

State

q State Environment Protection Policy (SEPP) Waters of Victoria objectives (Government of Victoria, 1988); q River Health Strategy; q Stressed Rivers Program; q Flora and Fauna Guarantee Act; and q Water Act.

The Department of Natural Resources and Environment developed the Victorian Water for the Environment Program, to provide water for the maintenance and restoration of environmental values in rivers and wetlands. The program’s objective is to increase environmental flows, whilst recognising existing entitlements.

The other State strategies and acts are aimed at overall environmental management. Environmental flows are one tool that can work with the Flora and Fauna Guarantee Act to help maintain threatened species or communities. SEpP and the River Health Strategy are working to set targets and guidelines for environmental conditions in Victorian waterways.

Regional

q Glenelg Regional Catchment Strategy q Water Quality in the Glenelg Catchment q Glenelg Catchment Waterway Strategy q Glenelg Hopkins Native Vegetation Plan

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 37 There are a series of regional plans and strategies that are relevant to the environmental flows study. The Regional Catchment Strategy recommends a series of actions and works that are aimed at improving ecosystem health, although not limited to the aquatic ecosystem. These actions generally in concept and action support the philosophy and implementation of the environmental flow recommendations. Water quality and specifically salinity is a key issues within the Glenelg River and although there are impacts on the flow regime the key actions to deal with this is through the Water Quality Strategy.

6.2 Catchment objectives Catchment objectives have been developed that are relevant to the overall catchment, detail from these objectives relevant to each reach is covered within the detailed reach objectives.

1) Provide an adequate environmental flow regime throughout the year that includes:

q periods of no flows but without extending their frequency or duration; q minimum environmental flows during low flow periods; q appropriate flushing flows to manage salinity and nutrient levels; and q large channel forming flows.

2) Maintain and restore longitudinal connectivity by:

q ensuring farm dam development in upper catchment does not impact flow levels and variability in downstream reaches; and q improving flow over/through existing weirs.

3) Maintain and improve (where possible) stream habitat condition to enhance:

q channel morphology (including large woody debris); q riparian vegetation; and q instream vegetation.

4) Maintain and enhance self-sustaining populations of endemic native fish with particular emphasis on threatened species.

5) Manage flows for 24 threatened flora species dependant on flows.

6) Ensure that links to other strategies are fostered to promote the benefits of environmental flows (e.g. implementation of a nutrient management plan to assist in reducing nutrient rich runoff).

6.3 Environmental objectives Specific environmental objectives for flow limited assets are listed in Table 6.1. The list of assets is derived from the identified assets of the Glenelg System in Appendix D.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 38 n Table 6-1: Environmental objectives for the Glenelg River Environmental Objective Process Relevant Flow Timing of Objectives Component Flow Component 1a Self sustaining populations of River Habitat Low All year Blackfish 1b Recruitment Freshes Winter/Spring 1c Movement High Winter/Spring

2a Self sustaining populations of Mountain Habitat Low All year Galaxias 2b Recruitment Freshes Winter/Spring 2c Movement High Winter/Spring

3 Self sustaining populations of Yarra Habitat Low All year Pygmy Perch

4a Self sustaining populations of Southern Habitat Low All year Pygmy Perch 4b Recruitment Freshes Winter/Spring

5a Self sustaining populations of Habitat Low All year Variegated Pygmy Perch 5b Recruitment Freshes Winter/Spring

6a Self sustaining populations of Dwarf Habitat Low All year Galaxias 6b Recruitment Freshes Winter/Spring

7 Sustainable River Swamp Wallaby- Maintenance Bankfull flows Spring grass

8 Sustainable River Red Gum community Maintenance Bankfull flows Winter/srping

9 Maintain diversity in channel form Habitat diversity High Winter/Spring

10 Maintenance of estuary ecosystem Restoration of High flows Spring natural flooding events

11a Maintain benthic community diversity Disturbance Cease to Flow Summer 11b Habitat Low Summer 11c Disturbance Freshes Winter/spring

12a Maintenance of water quality in pools Mixing, Low Summer destratification 12b Mixing, Fresh All year destratification

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 39 7. Discussion

The magnitude, duration, frequency and timing of flows are key aspects of a natural flow regime to maintain channel form and viable populations of freshwater biota. Alteration of the natural flow regime of Australian rivers has been shown to interfere with the biology and assemblage structures of aquatic flora and fauna (e.g. Gehrke et al. 1995, 1999, Koehn et al. 1995, Walker et al. 1994) and alter natural geomorphic processes such as erosion and sedimentation (e.g. Bird 1985, Erskine 1986, Benn and Erskine 1994, Burston and Good 1996, Brooks and Brierley 1997, Prosser et al. in press).

In the Glenelg River, the regulation of river flows through Rocklands Reservoir and associated deterioration in water quality and the condition and diversity of instream habitat due to excessive sedimentation are likely to have caused a decline in the health of the riverine ecosystem. (SKM 2001a).

Using a multi-disciplinary approach and integrated information on the ecology, hydrology, geomorphology and water quality within the study area we have recommended a flow regime that aims to maintain and where possible restore the environmental values of the Glenelg system. The recommended flow regime incorporates key components of the natural flow regime that are necessary for biological, geomorphological and physicochemical processes.

The key components of the natural flow regime and the magnitude, duration, frequency and timing of these components have been derived from modelled natural flow regimes. These components are considered critical for biological, geomorphological and physicochemical processes:

1) periods of cease to flow; 2) low flows; 3) freshes during periods of cease to flow/low flow; 4) freshes during spring; 5) flow variability; 6) medium/sustaining flows; and 7) High flow (channel forming).

These components are common for all defined reaches of the Glenelg River, although the first component (periods of cease to flow) is unique to Reach 1 and 2. The ecological, geomorphological and physicochemical significance of each of the hydrological regime components is outlined below.

7.1 Seasonal timing of releases The magnitude of an environmental flow is an important consideration when developing recommendations, but of similar importance is the timing of such releases on a seasonal scale. As biota frequently associate life stages, such as spawning in freshwater fish, with changes in temperature and other parameters it is imperative that environmental flows are provided at the appropriate time of the year to encourage

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 40 population growth. The recommendations have been presented based on season. Summer is defined as the months of December to May, inclusive. Winter is the months of July to October, inclusive. June and November are transition months.

7.2 Periods of cease to flow The cessation of flow is a common natural occurrence in Australian rivers. During these periods the river may contract to a series of isolated pools thus decreasing the diversity and availability of aquatic habitats to instream biota. Furthermore biota in these pools are likely to be subject to intensified predation and physicochemical stresses (e.g. low dissolved oxygen concentrations).

Whilst these factors may be considered to have an immediate detrimental effect on aquatic flora and fauna, they are important disturbance mechanisms that prevent the system being dominated by any particular group of organisms. The duration and frequency of cease to flow events have been substantially increased in the Glenelg River downstream of Rocklands Reservoir. Consequently, it is recommended that a reduction in cease to flow events occur to a frequency and duration similar to that which would occur under natural conditions.

7.3 Baseflows Whilst the Glenelg River may cease to flow (e.g. summer-autumn), under a natural flow regime, the river would be subject to periods of low or base flow when not ceasing to flow. The daily baseflow for each site is equal to the median flow that would have occurred under natural conditions, during that period. These flows (as specified in the recommendations) would inundate bars between pools thus providing habitat for macroinvertebrates and small-bodied fish. The inundation of bars would also provide important linkages between pools (refuge habitats) and may enable the redistribution of mobile biota from areas of poor water quality or unfavourable biotic interactions.

7.4 Freshes during periods of cease to flow/low flow Cease to flow periods are a natural perturbation to the system, these impose a stress on the ecosystem which helps support the maintenance of community diversity. A key component of the flow regime linked to the cease to flow periods is the brief summer freshes that result from flash summer rains. Summer freshes, those flows that exceed the natural median daily flow, are important in ephemeral rivers for the maintenance or improvement of water quality. These freshes provide a brief respite to the system and are critical to the maintenance of the ecosystem.

Summer freshes are unlikely to cause mixing of the saline pools that characterise the mid reaches of the Glenelg River. In the Wimmera River Anderson and Morison (1989) suggest that flows in excess of 3,000 ML/d are required for the destratification of large pools. Summer freshes have been suggested to prevent significant increases in salinity in the Wimmera River that occurs at flows of less than 10-20 ML/d (SKM 1997). It follows that in the mid reaches of the Glenelg River where the saline pools exist that the summer freshes are critical in ensuring that the salinity does not exceed tolerable levels any further.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 41 7.5 Spring freshes Spring freshes are an important ecological component of the Glenelg River system. Seasonal high flows during spring may stimulate migration and/or spawning of native fish species that inhabit the region. In addition, spring freshes make available inchannel habitats such as vegetated bars, benches and undercuts. These habitats may be important for the colonisation of macroinvertebrates and as spawning sites and refuges for native fish. High flows during spring may also mobilise fine organic material that would otherwise smother instream habitats.

7.6 Flow variability Maintaining natural variability in stream discharge over this period is important for both ecological and geomorphological processes. Under natural conditions variations in water surface level and associated wetting and drying regimes of stream banks are important for the creation of channel forms (e.g. pools, riffles, bars, benches) and habitat attributes (e.g. large woody debris transport and placement). However, constant flows and water surface levels tend to accelerate the rate of scour at the bank toe which, in turn, may lead to bank slumping. Furthermore, constant discharge over this period (May to November) may be detrimental to life history strategies and subsequent recruitment of native fish, macrophyte and macroinvertebrate species.

7.7 High flows Bank-full flows represent disturbances that occur naturally in the Glenelg River system. Although bank-full flows are unpredictable and episodic in the Glenelg River, these flows provide lateral connectivity between in-channel and flood plain habitats. Maintaining occasional inundation of the flood plain is ecologically important and is known to provide significant carbon returns to the river after a period of significant production (plants, algae, micro and macroinvertebrates and possibly fish). Significant inputs of carbon to the river during floodplain inundation may be critical in maintaining food webs in systems which experience periods of low and cease to flow conditions (Davies et al. 2001).

High flow regimes including bank-full flows are also important geomorphologically in shaping and maintaining river and anabranch channels and also in preserving the condition and availability of instream habitats. For example, bank-full flows will assist in the resuspension and distribution of sediments that would otherwise smother important benthic habitats (large woody debris and leaf-packs).

High flows occur within the stream channel. Flows greater than these high flows would spill outside the river channel and are known as overbank flows. Although overbank flows occur naturally in many river systems, such flows will not be recommended due to the extraction of water under the current level of water resource development in the catchment being unlikely to impact on the frequency and duration of these events. In addition, these overbank flows can not be regulated by existing infrastructure as they occur outside of the stream channel, therefore there is no means of managing a flow of such magnitude.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 42 8. Recommendations

The recommendations for the Glenelg River have been developed to maximise the environmental benefits of the water provided. In some cases a series of recommendations allow for future increases in environmental flows as provisions for the environment may increase. These recommendations have been developed with the best available knowledge at the time of this project. Further developments and collection of raw data will support the ongoing development and revision of this work.

The proposed environmental flow regime has been developed on a reach-by-reach basis to maximise environmental health through the provision of favourable water quality and aquatic habitat conditions. The timing and magnitude of environmental flows is important for any benefit to be realised within an aquatic environment. The timing of environmental flows may be described as months or seasons.

Recommendations are provided in two forms. The first are the direct flow based recommendations. These recommendations are presented in a series of tables that summarise the environmental flow regime. The determination of the frequency and duration of the selected magnitude in these tables has been assisted by spells plots. The data has been analysed using the program, GetSpells. GetSpells examines the daily flow series and determines the number of times (events) that the flow was above (or below, if selected) a given magnitude and the duration of each event (Figure 8-1). The program then presents this information in a graphical form. The program produces two graphs for each assessment; one showing the frequency of the events per 100 years and the second showing statistics on the duration of these events.

The second component of the recommendations is the supporting recommendations that are not specifically flow regime components but directly support the efficacy of the recommended flow regime.

It may not be possible to implement fully all of the recommendations presented in each year, particularly during dry years. For example, 5 summer freshes may not be provided within a given year, however such variation in the availability of water would have occurred. Subsequently, the implementation of the recommendations should account for dry and wet years. During dry years, at least low flows will be provided, while during wet years low flows and freshes will be provided. It is suggested that a 5 year period be used to measure the implementation of the recommendations and the annual frequency be over that period.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 43 F requency Plot

90 D i ck R

80 Frequency plot indicates the s

r 70

a number of e y

times that such

0 60 0

1 a threshold

e 50 occurs per 100 p

c years e.g. 88

n 40 e

u times per 100. q e

r 30 F 20

0 1 T hreshold (M L )

Percenti l e Pl ot

D i ck R 25% of events

These two d 14 have a duration of l o h

points s 10 .0%greater than this e r 12 20 .0% h

indicate the t

50 .0%point (12 days). w

duration that o 80 .0% l 10 e

b 90 .0%This point

50% of the ) s

y indicates the

events occur a 8 d ( for, i.e. most median (mid- n o

i 6 t point) duration of

events occur a r u

for 2 to 12 d events (3.5 days).

l 4 l e

days. p S 2 25% of events Natural have a duration of 0 less than this 1 point (2 days). T hreshold (M L) Current n Figure 8-1 An example of the two graphs produced by GetSpells.

8.1 Flow Recommendations 8.1.1 Reach 1 – Rocklands Reservoir – Chetwynd River The following section details the flow recommendations (Table 8-1) and rationale for these recommendations developed for Reach 1 in the Glenelg River.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 44 n Table 8-1 Flow Recommendations Reach 1 – Rocklands Reservoir to Chetwynd River

River Glenelg River Reach Rocklands – Chetwynd River Compliance Point Harrow Gauge No. 238 210

Flow Rationale

Season Magnitude Frequency Duration Objective Evaluation

Summer Minimum Annual Dec – May 1a, 2a, 3, 4a, 5a, 6a, Self-sustaining (Dec – May) 11 ML/d 11b, 12a populations of small bodied fish > 64 ML/d 5 annually Minimum 6 12b Self-sustaining days populations of small bodied fish

June 100 ML/day Annual June

Winter Minimum Annual July-Oct 1a, 2a, 3, 4a, 5a, 6a, Minimum Flow (Jul-Oct) 150 ML/d 11b, 12a Maintained > 1400 ML/d 3 annually 3 days 8, 11c Occurrence of large flow

Spring > 450 ML/d 2 annually 10 days 1b, 1c, 2b, 2c, 4b, 5b, Self-sustaining (Sept) 6b, 7,12b populations of fish (Mountain Galaxias, River Blackfish, Common Galaxias, Spotted Galaxias) Off-stream habitats wetted

November 130 ML/day Annual November 7, 8

Although the Glenelg River does cease to flow in this reach (Figure 8-3), it is an annual event of very short duration (less than 1 week). Consequently a cease to flow recommendation is not made, particularly in light of the saline groundwater inputs that would cause a significant stress to the ecosystem in periods of no flow.

The existing minimum flow recommendation is for a passing flow of 11 ML/day at Harrow (Mitchell et al. 1996). The new recommendation is to maintain the 11 ML/day as the minimum flow, as it links the key habitats through the reach (Figure 8-5). This minimum flow should apply to the whole of the summer period. The minimum flow is important to keep water running through the reach and reduce the impact of the saline intrusions to the ecosystem. This recommendation is supported by previous studies by Mitchell et al. (1996). A priority for implementation are the summer freshes, these freshes provide a critical respite from the low summer flow and are n Figure 8-2 Shallow habitats in Glenelg ecologically important. The flow River Reach 1.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 45 of the fresh is often defined as the median (50%) flow for the period, in this case 64 ML/day is the recommended magnitude as it provides a greater flow through the habitats (Figure 8-5). To maximise the ecological and water quality benefit of summer freshes the median natural duration of 6 days is recommended as the minimum duration (Figure 8-4). These freshes naturally occurred, on average, 5 times annually. The recommendation is that 5 freshes be maintained on an annual basis. This fresh will wet many of the areas on bars and reduce the saline pool stratification.

Ex ceedance F requency Plot

3 10

2 10 R k c

i 1

D 10

0 10

-1 10 0 10 20 30 40 50 60 70 80 90 100 T i m e Exceeded (%) n Figure 8-3 Natural flow duration Glenelg River Reach 1 (Dick Roberts) (Summer: December – May inclusive).

F r eq uenc y P l o t Per cent i l e P l ot 5 5 0 S cenar io 1 1 8 S cenario 1 5 0 0 d l o

h 1 6 4 5 0 1 0.0% s e

r 2 5.0% s h r t 1 4 a 4 0 0 5 0.0% e e

y v 7 5.0% o

0 3 5 0 b 1 2 9 0.0% a 0

1 ) s

r 3 0 0

y 1 0 e a p d

(

y 2 5 0

c n 8 n o i e t u 2 0 0 a q r 6 e u r d F 1 5 0 l l

e 4 p

1 0 0 S 2 5 0 0 0 6 4 6 4 T h resho l d (M L ) T hresho l d (M L ) n Figure 8-4 Natural duration and frequency of flows above the recommended fresh (64 ML/day) in the Glenelg River Reach 1. Current research is suggesting that a translucent dam operational policy could provide significant environmental benefits, returning flow variability to a system downstream. The strategy releases a certain percentage of the flows entering a storage directly downstream. Thus any variability in the inflows is reflected in the flows downstream of the storage. The spring freshes recommendation is aiming to return the variability around the high flows. It is suggested that in the long term a translucent dam operation at Rocklands Reservoir may more effectively provide the required flow

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 46 components and variability. When current research is completed, and if it confirms the efficacy of translucent dam operations for the environment, a similar operational regime should be examined for Rocklands Reservoir. The outlet structures at Rocklands Reservoir may need modification to implement a translucent dam policy. In the interim a minimum winter flow and spring freshes are recommended. The magnitude of the spring fresh is the median spring flow of 450 ML/day.

.06 127

126

125

124 Elevation (m)

123

122 0 10 20 30 40 50 60 70 Station (m) n Figure 8-5 Cross section showing 11 ML/day (filled area) and 64 ML/day (solid line) in channel at Glenelg River Site Reach 1. In winter the minimum flow of 150 ML/day is aimed to provide significant water through the inchannel habitats. This flow provides a continuous flow through the reach and will have several benefits. It will provide longitudinal connectivity for the mobile species in the reach, such as the native fish species. In addition it will wet the margins of the channel where the emergent vegetation is found and wet low lying bars a key habitat.

A spring or winter fresh is important in this reach to provide the biological cues for the freshwater fish community. These cues can induce spawning or movement. The recommended magnitude is greater than 450 ML/day the median flow for this period. This flow will also wet the bulk of the channel. Multiple events are recommended to allow a biological response, 2 events annually meets the natural frequency of these events (Figure 8-7). A minimum duration of 10 days is the median natural duration and will allow an effective biological response.

The sand accumulation in this reach means that large sediment mobilising flows are a key feature of the recommended flow regime. The recommended winter high flow n Figure 8-6 Glenelg River Reach 1 – of 1400 ML/day is between the planview with water level at 1400 ML/day. 20% and 30% natural flow and is a significant annual flow event. The recommended flow (1400 ML/day) wets all major habitats in the reach (Figure 8-6) and would induce significant sediment mobilisation. Larger flows that inundate the complete channel including the mid channel bars would be only when Rocklands Reservoir is spilling. To promote fine sediment movement and inputs of fresh water to the pools the recommended frequency is 3 events annually, this replicates the natural frequency of the events (Figure 8-7). Because the

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 47 responses are physical rather than biological, the duration of the events can be a shorter 3 days.

June and November are the transitional months between the high and low flow seasons. The recommended flows for these periods are the 80% flows for the relevant month. The ramping up and ramping down of flow through these transitional months should be a gradual change in flow.

Due to the current lack of a suitable compliance point for the flow recommendations, it is recommended that the streamflow gauge at Harrow (238 210) be reactivated.

In dry years it may not be possible to implement fully all of the recommendations. For example, there may not be sufficient water to implement the 5 summer freshes within a given year. Naturally there would have been this variation. As such the implementation of the recommendations should account for dry and wet years. It is suggested that a 5 year period be used to measure the implementation of the recommendations and the annual frequency be over that period.

Fr equency P l ot 9 0 Per cent i l e P l ot

Scen ar io 1 Scen ar io 1 3 0 0 8 0 d l o h s 7 0 10.0 % e r

s 2 5 0 25. 0% r h t a

50. 0% e e

y 6 0 v 75. 0% o 0 b

0 2 0 0 90.0 % a 1

) 5 0 r s e y p a

d y 1 5 0 ( 4 0 c n n e o i u t q a 3 0 e r r 1 0 0 u F d

l 2 0 e p

5 0 S 1 0

0 0 4 50 1 4 00 4 50 1 4 00 T hr esho l d (M L ) T hr esho l d (M L ) n Figure 8-7 Natural duration and frequency of spells above the spring fresh (450 ML/day) and winter high flow (1400 ML/day) thresholds (ML/day) in the Glenelg River Reach 1.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 48 n Table 8-2 Maximum water depth for each cross section at each recommended flow Reach 1 – Rocklands Reservoir to Chetwynd River Cross Flow Minimum Water Maximum Flow Area Water Section ML/day Channel Surface Depth (m) (m 2) Surface Elevation Elevation (m) Width

1 11 122.94 123.07 0.13 0.16 2.72 1 23 122.94 123.11 0.17 0.3 3.69 1 150 122.94 123.28 0.34 1.47 10.81 1 450 122.94 123.44 0.5 3.76 19.73 1 1400 122.94 123.66 0.72 8.79 25.6

2 11 122.73 123.14 0.41 1.66 9.95 2 23 122.73 123.21 0.48 2.54 13.97 2 150 122.73 123.48 0.75 7.7 25.35 2 450 122.73 123.71 0.98 15.28 35.94 2 1400 122.73 124.06 1.33 29.61 44.9

3 11 122.06 123.14 1.08 7.99 13.17 3 23 122.06 123.21 1.15 9.03 14.42 3 150 122.06 123.49 1.43 14.22 24.93 3 450 122.06 123.75 1.69 21.11 29.59 3 1400 122.06 124.13 2.07 33.45 34.95

4 11 121.47 123.14 1.67 12.42 26.78 4 23 121.47 123.22 1.75 14.55 28.68 4 150 121.47 123.5 2.03 24.17 37.96 4 450 121.47 123.75 2.28 34.33 41.54 4 1400 121.47 124.15 2.68 51.74 46.69

5 11 122.47 123.14 0.67 4.93 26.38 5 23 122.47 123.22 0.75 7.09 28.39 5 150 122.47 123.5 1.03 15.52 32.02 5 450 122.47 123.76 1.29 25.5 42.77 5 1400 122.47 124.16 1.69 45.13 57.16

6 11 121.36 123.14 1.78 28.18 24.43 6 23 121.36 123.22 1.86 30.13 25.45 6 150 121.36 123.5 2.14 37.95 30.33 6 450 121.36 123.76 2.4 46.62 35.56 6 1400 121.36 124.17 2.81 63.04 45.63

For the purpose of monitoring. the maximum water depth was calculated for each recommended daily flow at each cross section (Table 8-2). Following implementation of specific flows it will be possible to validate the assumption of the recommendation by checking the maximum water depth at each cross section within the site. The site plan view and cross section profiles are provided to assist in the determination of the maximum channel depth across each cross section (Figure 8-8).

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 49 Cross Section: 1 54H 0562172 Cross Section: 2 54H 0562200 UTM 5885340 UTM 5885336

132 132

130 130

128 128

126 126

124 124

122 122

120 120 0 10 20 30 40 50 60 70 80 90 100 110 0 10 20 30 40 50 60 70 80 90 100 110

Cross Section: 3 54H 0562245 Cross Section: 4 54H 0562281 UTM 5885339 UTM 5885313

132 132

130 130

128 128

126 126

124 124

122 122

120 120 0 10 20 30 40 50 60 70 80 90 100 110 0 10 20 30 40 50 60 70 80 90 100 110

Cross Section: 5 54H 0562294 Cross Section: 6 54H 0562317 UTM 5885280 UTM 5885246

132 132

130 130

128 128

126 126

124 124

122 122

120 120 0 10 20 30 40 50 60 70 80 90 100 110 0 10 20 30 40 50 60 70 80 90 100 110

n Figure 8-8 Cross Sections Site 3: Glenelg River upstream of Dick Roberts’ property, upstream of Harrow For each flow recommendation for Reach 1, there are a series of risks associated with not meeting the respective recommendation. Subsequently, these recommendations have been prioritised based on the level of risk to the aquatic environment of not being met (Table 8-3). The first priority for Reach 1 is the maintenance of a minimum summer flow to maintain suitable conditions. If this flow is not met, water quality would be compromised to the detriment of small bodied fish and the benthic community. The flow recommendations with the lowest priority for implementation is the winter high flow of 1400 ML/d. If this flow recommendation is not met, there is likely to be a lack of diversity in channel form and subsequently aquatic habitat. In

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 50 addition, the lack of a flow of such magnitude would lead to a loss of benthic community diversity and a build up of sand in the channel. n Table 8-3 Priority for implementation of flow recommendations for Reach 1, indicating risk of not meeting respective recommendations.

Season Magnitude Priority Risk if not met

Summer Minimum A Adverse water quality conditions and low availability of aquatic habitat that (Dec – May) 11 ML/d may lead to deleterious effects on small bodied fish and the benthic community Summer >23 ML/d C Adverse water quality conditions and low availability of aquatic habitat that (Dec – May) may lead to deleterious effects on small bodied fish Winter Minimum B Not mimicing natural flow variability as well as adverse water quality conditions (Jul – Oct) 150 ML/d and limited availability of aquatic habitat Winter >1400 ML/d E Lack of diversity in channel form and subsequently aquatic habitat. Also loss of (Jul – Oct) benthic community diversity and a build up of sand in the channel Spring >450 ML/d D Lack of recruitment of many fish species and a reduction in water quality (Sept) conditions to the detriment of aquatic species

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 51 8.1.2 Reach 2 – Chetwynd River to Wannon River The following section details the flow recommendations (Table 8-4) and the rationale used in the development of those recommendations for Reach 2 of the Glenelg River. n Table 8-4 Reach 2 Chetwynd River to Wannon River

River Glenelg River Reach Chetwynd River – Wannon River Compliance Point Roseneath Gauge No. 238 211

Flow Rationale

Season Magnitude Frequency Duration Objective Evaluation

Summer 0 ML/d 3 annually Maximum 8 11a Cease to flow occurs (Dec – May) days Minimum Annual Dec – May 1a, 2a, 3, 4a, 5a, 6a, Self-sustaining 16 – 77 ML/d (excl. CTF) 11b, 12a populations of small bodied fish > 77 ML/d 4 annually 7 – 15 days 12b Self-sustaining populations of small bodied fish

June 93 ML/d Annual June 1a, 2a, 3, 4a, 5a, 6a, Self-sustaining 8a, 11a, 12b, 13a populations of small bodied fish

Winter Minimum Annual July – Oct 1a, 2a, 3, 4a, 5a, 6a, Minimum Flow (July – Oct) 385 ML/d 11b, 12a Maintained > 3600 ML/d 2 annually Minimum 4 7, 8, 11c Occurrence of large flow days

November 110 ML/d Annual November 1a, 2a, 3, 4a, 5a, 6a, Self-sustaining 11b, 12a populations of small bodied fish

Spring > 700 ML/ d 2 – 3 annually 5 days 1b, 1c, 2b, 2c, 4b, 5b, Self-sustaining (Sept) 6b, 12b populations of fish (Common Galaxias Mountain Galaxias, River Blackfish, Pygmy Perch) Off-stream habitats wetted

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 52 Hydrological analysis indicates that cease to flow events would occur naturally within Reach 2 approximately 30 % of the time during the identified summer period of December to May, inclusive (Figure 8-10). The events are relatively short with a median duration of 4 days and 75% of events occurring for no longer than 8 days, although the average frequency is 3.5 times per year (Figure 8-11). It is recommended that these cease to flow events be maintained to occur 3 times annually and last no longer than 8 days. The occurrence of such flow periods benefits the aquatic ecosystem by providing an environmental disturbance that n Figure 8-9 Cross section 3 at Site 5 prevents the domination of an (Roseneath) Reach 2 Glenelg River. area by a particular macroinvertebrate species, as many species would be reduced in their abundance and distribution during the dry period. Species diversity would subsequently be increased on rewetting of the channel. Extending the duration of these events risks impacts on the ecosystem.

Cease to flow events should not be implemented until there is further improvement in water quality, specifically salinity throughout the reach. In the current catchment conditions, saline inputs into the river lead to saline pool formation in this reach of the Glenelg River. A cease to flow period under these conditions could significantly exacerbate this issue and result in impacts to the aquatic ecosystem. Consequently, in the interim it is not recommended to implement the cease to flow period until the impacts of saline pool formation has been reduced by catchment actions.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 53 103 ) y a d / 2 L 10 M (

w o l 101 F

y l i a 0 D 10

10-1 0 10 20 30 40 50 60 70 80 90 100 T i m e E xceeded ( % )

n Figure 8-10 Flow duration Glenelg River Reach 2 at Site 5 (Roseneath) (Summer December – May inclusive).

Per c ent il e Pl ot F r eq uenc y Pl ot 400 S cenar io 1 25

d 350 l o h

s 10.0 % e r 25 .0% s 300 h r t 20 a

50 .0% e y w

o 75 .0% l 0 250 e 90.0 % 0 b 1

) r

s 15 e y p

a 200

d y ( c

n n e o

i u 150 t

10 q a e r r u F d

l 100 l e

p 5 S 50

0 0 1 16 1 16 T hre sh ol d (ML ) T hre sh ol d (ML ) n Figure 8-11 Spell analysis Glenelg River Reach 2 at Site 5 (Roseneath), spells less than threshold (1 ML/day, 16 ML/day) (Summer: December – May inclusive). In summer the recommended minimum flow is 16 ML/day, this provides a minimum level of connectivity through the habitats in the reach (Figure 8-12). It is also the equivalent flow to the minimum flow recommendation in Reach 1, accounting for inflows over the distance between the two compliance points. Cross section 3 is a low flow control and at the minimum flow of 16 ML/day there would be approximately 0.08m of water passing over this point. This water depth presents a potential risk, but the sandy nature of the Glenelg River at this location would suggest that such a discharge would maintain flow through the large woody debris (LWD), roots and sand in this cross section (Figure 8-9). The maintenance of a connecting flow within this reach would assist in maintaining a water quality within the pools over summer. This

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 54 flow would mix the water in these pools to the benefit of temperature, dissolved oxygen and salinity.

Glenelg Plan: Site 5 - roseneath TS3 .06 55.0

54.5 54.0 53.5

53.0 52.5 Elevation (m) 52.0 51.5

51.0 0 20 40 60 80 Station (m) n Figure 8-12 Cross section 3 Site 5 (Roseneath) Glenelg River Reach 2, showing water level at recommended summer minimum flow 16 ML/day. The summer fresh for Reach 2 is greater than the median summer flow of 77 ML/day (Table 8-5). The recommendation for the summer fresh is for it to last at least 7 days on average 4 times annually. This recommendation means that the freshes will exceed the duration of 75% of the natural events (Figure 8-13). These short, but frequent, summer freshes will act to mix pools and minimise the risk of saline pool formation to the benefit of aquatic dependent species. n Table 8-5 Flow percentiles Glenelg River Reach 2 (Summer: December-May inclusive). Site 10% 20% 30% 40% 50% 60% 70% 80% 90% BurkesB 335.6 193.6 137 105.6 86.5 70.5 55.4 14.5 4.2 Roseneath 356 199.1 138.8 103.4 77.2 55.5 29.4 15.8 0.1 Section Rd 434.5 243 169.4 126.2 94.3 67.8 35.9 19.3 0.1

Pe r cent i le Pl ot F r equ enc y Pl ot 450 90 Sce nar io 1 d

l 400

o 80 h

s 1 0.0 % e r

25. 0% s 350 h r

t 70 a

50. 0% e e y v 300

o 75. 0% 60 0 b 0

a 9 0.0 % 1

) r

s 250 e

y 50 p a

d y ( c 200 n

n 40 e o i u t q a e

r 150 30 r u F d

l l 100 e 20 p S 10 50

0 0 16 77 16 77 T hr esh ol d ( ML ) T hr esh ol d ( ML ) n Figure 8-13 Spell analysis Glenelg River Reach 2 at Site 5 (Roseneath), spells greater than threshold (16 ML/day, 77 ML/day) (Summer: December – May inclusive). The winter minimum flow is aimed at maintaining a flow over a range of habitats throughout the site. The recommended minimum is 385 ML/day, which is between

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 55 the 70% and 80% flow for the winter period naturally (Table 8-6). Similar to the minimum flow recommendation during the summer period, the winter minimum flow is aimed at improving water quality conditions, including diluting salinity in pools, to the benefit of aquatic dependent species. n Table 8-6 Flow percentiles Glenelg River Reach 2 (Winter: July-October inclusive). Site 10% 20% 30% 40% 50% 60% 70% 80% 90% BurkesB 3210.8 2075.6 1472.2 1122.4 837.1 652.3 490.0 345.6 221.8 Roseneath 4153.2 2510.7 1647.5 1204.6 926.6 653.3 477.8 348.8 209.1 SectionRd 5068.4 3063.9 2010.5 1470.1 1130.7 797.3 583.1 425.7 255.1

The accumulation of sand within this reach of the Glenelg River has smothered the aquatic habitat, hence large sediment mobilising flows are a key recommended feature of the flow regime. During winter the recommended large flows can be utilised to displace this sand deposit. To prevent the accumulation of further sand downstream, it is also recommended that sand extraction be conducted in addition to the large flows to remove, rather than shift, the problem. The recommended flow is that in excess of 3600 ML/day for a minimum of 4 days twice annually (Figure 8-14). The relatively short duration annual event will be able to provide the large disturbance required.

Per cen t il e Pl ot F r eq uen cy Pl ot 90 300 Scena rio 1 d l 80 o

h 250 s 10. 0% e r 25 .0% s

70 r h t a

50 .0% e e y v 75 .0% 200

o 60 0 b 0

a 90. 0% 1

) r s 50 e y p a

150 d y ( c 40 n n e o i u t q a

r e 100

30 r u F d

l l

e 20 p

S 50 10

0 0 707 3653 707 3653 T hr esho l d ( ML ) T hr esho l d ( ML ) n Figure 8-14 Spell analysis Glenelg River Reach 2 at Site 5 (Roseneath), spells greater than threshold (707 ML/day, 8653 ML/day) (Winter: July - October inclusive). Many aquatic biota utilise increases in flow to induce certain stages of their lifecycle. Many fish species utilise these increases in flow to induce spawning, and such flows permit the access to previously inaccessible habitats. The proposed spring freshes would be utilised by many fish species in the Glenelg River to gain access to suitable sites for spawning. The recommended spring fresh is greater than 700 ML/day for a minimum of 5 days, 2 – 3 time annually. Although 75% of the events would have occurred for at least 4 days (Figure 8-14), 5 days is a suggested minimum as this has been agreed as the minimum duration for an event to have ecological significance.

June and November are the transitional months between the high and low flow seasons. The recommended flows for these periods are the 80% flows for the relevant month. The recommendation for June is 83 ML/day, and 110 ML/day in November.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 56 The ramping up and ramping down of flow through these transitional months should be a gradual change in flow.

The most appropriate location for gauging the compliance with the recommended environmental flows is Warrock Road at Roseneath. A gauge is not currently established at this site but it is recommended that such a gauge be established in the near future. Until this gauge is created it is recommended that gauge 238 211 at Dergholm be utilised in the interim. n Table 8-7 Maximum water depth for each cross section at each recommended flow Reach 2 – Rocklands Reservoir to Chetwynd River. Cross Flow Minimum Water Water Depth Flow Area Water Section ML/day Channel Surface (m) (m 2) Surface Elevation Elevation (m) Width (m) 1 16 51 51.5 0.5 1.74 8.55 1 77 51 51.69 0.69 3.74 11.47 1 700 51 52.22 1.22 10.87 15.1 1 385 51 52.03 1.03 7.99 13.92 1 3600 51 53.28 2.28 30.75 25.54

2 16 51.24 51.46 0.22 0.59 6.22 2 77 51.24 51.6 0.36 2 13.72 2 700 51.24 52.1 0.86 13.85 29.05 2 385 51.24 51.88 0.64 7.65 25.74 2 3600 51.24 53.2 1.96 49.75 36.7

3 16 51.17 51.25 0.08 0.24 4.14 3 77 51.17 51.36 0.19 0.78 5.98 3 700 51.17 52.03 0.86 9.12 18.83 3 385 51.17 51.71 0.54 3.73 12.42 3 3600 51.17 53.18 2.01 45.89 41.49

4 16 50.19 50.86 0.67 2.46 7.42 4 77 50.19 51.1 0.91 4.29 8.08 4 700 50.19 51.94 1.75 15.33 20.27 4 385 50.19 51.62 1.43 9.47 14.97 4 3600 50.19 53.1 2.91 50.5 38.67

5 16 49.41 50.86 1.45 14.89 15.85 5 77 49.41 51.1 1.69 18.79 16.85 5 700 49.41 51.94 2.53 37.56 30.71 5 385 49.41 51.62 2.21 28.72 23.19 5 3600 49.41 53.09 3.68 84.93 52.08

6 16 50.57 50.86 0.29 0.64 4.4 6 77 50.57 51.09 0.52 1.95 6.58 6 700 50.57 51.9 1.33 9.15 11.23 6 385 50.57 51.59 1.02 5.95 9.44 6 3600 50.57 53.02 2.45 38.91 36.02

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 57 n Figure 8-15 Plan View Site 5: Glenelg River at Roseneath, Reach 2.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 58 Cross Section: 1 54H 0523995 Cross Section: 2 54H 0524013 UTM 5856182 UTM 5856164

56 56

55 55

54 54

53 53

52 52

51 51

50 50

49 49 0 10 20 30 40 50 60 70 80 90 100 110 0 10 20 30 40 50 60 70 80 90 100 110

Cross Section: 3 54H 0523999 Cross Section: 4 54H 0524027 UTM 5856163 UTM 5856160

56 56

55 55

54 54

53 53

52 52

51 51

50 50 49 49 0 10 20 30 40 50 60 70 80 90 100 110 0 10 20 30 40 50 60 70 80 90 100 110

Cross Section: 5 54H 0524039 Cross Section: 6 54H 0524071 UTM 5856081 UTM 5856101

56 56

55 55

54 54

53 53

52 52

51 51

50 50

49 49 0 10 20 30 40 50 60 70 80 90 100 110 0 10 20 30 40 50 60 70 80 90 100 110

n Figure 8-16 Cross Sections Site 5: Glenelg River at Roseneath. For each flow recommendation for Reach 2, there are a series of risks associated with not meeting the respective recommendation. Subsequently, these recommendations have been prioritised based on the level of risk to the aquatic environment of not being met (Table 8-8), which do not necessarily correspond to the relative increases in flow magnitude. The first priority for Reach 2 is the maintenance of a minimum summer flow to maintain suitable conditions. If this flow is not met, water quality would be

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 59 compromised to the detriment of small bodied fish and the benthic community. The flow recommendations with the lowest priority for implementation is the winter high flow of 3600 ML/d. If this flow recommendation is not met, there is likely to be a lack of diversity in channel form and subsequently aquatic habitat. In addition, the lack of a flow of such magnitude would lead to a loss of benthic community diversity and a build up of sand in the channel. n Table 8-8 Priority for implementation of flow recommendations for Reach 2, indicating risk of not meeting respective recommendations.

Season Magnitude Priority Risk if not met

Summer 0 ML/d E Loss of benthic community diversity (Dec – May) Summer Minimum A Adverse water quality conditions and low availability of aquatic habitat that (Dec – May) 16-77 ML/d may lead to deleterious effects on small bodied fish and the benthic community Summer >77 ML/d C Adverse water quality conditions and low availability of aquatic habitat that (Dec – May) may lead to deleterious effects on small bodied fish Winter Minimum B Not mimicing natural flow variability as well as adverse water quality conditions (Jul – Oct) 385 ML/d and limited availability of aquatic habitat Winter >3600 ML/d F Lack of diversity in channel form and subsequently aquatic habitat. Also loss of (Jul – Oct) benthic community diversity and a build up of sand in the channel Spring >700 ML/d D Lack of recruitment of many fish species and a reduction in water quality (Sept) conditions to the detriment of aquatic species

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 60 8.1.3 Reach 3 – Wannon River to Tidal Extent The following section details the flow recommendations (Table 8-9) and the rationale used in the development of those recommendations for Reach 3 of the Glenelg River. n Table 8-9 Reach 3 – Wannon River to Tidal Extent

River Glenelg River Reach Wannon River – Tidal Extent Compliance Point Dartmoor Gauge No. 238206

Flow Rationale

Season Magnitude Frequency Duration Objective Evaluation

Summer Minimum Annual Dec – May 1a, 2a, 3, 4a, 5a, 6a, Self-sustaining (Dec – May) 83 ML/d 11b, 12a populations of small bodied fish > 216 ML/d 4 annually Minimum 12b Self-sustaining 5 days populations of small bodied fish

June 180 ML/d Annual June 1a, 2a, 3, 4a, 5a, 6a, Self-sustaining 11b, 12a populations of small bodied fish

Winter Minimum Annual July – Oct 1a, 2a, 3, 4a, 5a, 6a, Minimum Flow (July – Oct) 629 ML/d 11b, 12a Maintained

November 130 ML/d Annual November 1a, 2a, 3, 4a, 5a, 6a, Self-sustaining 11b, 12a populations of small bodied fish

Spring > 2200 ML/d 2 – 3 annually Minimum 5 1b, 1c, 2b, 2c, 4b, 5b, Self-sustaining (Sept) days 6b, 7,11c, 12b populations of fish (Common Galaxias, Australian Smelt)

Recommendations in this reach could be divided into two components. A cease to flow is a relevant feature of the flow regime near Sandford, whereas it is not near Dartmoor (Figure 8-17; Figure 8-18). The difference in the flow regime is likely to be a result of the different positions in the catchment, with the region near Sandford being a losing greater water than it gains. Losses occur for a variety of reasons in rivers including evaporation, seepage into ground water and the occurrence of subterranean flow that will resurface further downstream.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 61 4 1 0

) 3

y 1 0 a d /

L Dartmoor 2 M

( 1 0 Sandford

w o l 1 F

1 0 y l i a

D 0 1 0

1 0- 1 0 1 0 20 30 40 50 60 70 8 0 90 100 T im e Exceeded (% )

n Figure 8-17 Flow duration Glenelg River Reach 3 at Site 7 – Sandford (Red/Solid) and Site 8 – Dartmoor (dotted) (Summer December – May inclusive).

Per cent i le Plot F r eq uency Pl ot 8 Sce nar io 1 350 d

l 7 o h

s 1 0.0% e

r 300 2 5.0 % s

6 r h t a

5 0.0 % e w y

o 7 5.0 %

l 0 250

e 5 9 0.0% 0 b 1

) r s e y

p 200

a 4

d y ( c

n n e o

i 3 u 150 t q a e r r u F d

100

l 2 l e p S 1 50

0 0 1 1 T h resh ol d (M L ) T h resh ol d (M L ) n Figure 8-18 Spell analysis Glenelg River Reach 3 at Site 7 (Sandford), spells less than threshold (1 ML/day) (Summer: December – May inclusive). The recommended minimum summer flow of 83 ML/day through Reach 3 is aimed to provided longitudinal habitat connectivity through the reach. The river is a wide U-shaped channel in this lower reach and the minimum flow is needed to be significantly higher that that in upstream reaches to provide this connectivity to benefit water quality and subsequently aquatic species (Figure 8-19; Figure 8-23).

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 62 n Figure 8-19 Glenelg River Reach 3, Site 8 (Dartrmoor) – indicating wide channel and abundance of woody debris. The summer and spring freshes are the key components of the flow regime that should be implemented as a priority in this reach. The summer freshes, flows greater than 216 ML/day (Table 8-10), naturally occurred on average 4 times per year (Figure 8-20). The recommendation has been to mimic this frequency with a duration for a minimum of 5 days. Naturally 75% of the events lasted for 7 days minimum, but 5 days is considered a minimum duration for events to be ecologically relevant and it was considered more important to maintain the annual frequency. These freshes will improve water quality conditions, particularly temperature, dissolved oxygen and salinity, to the benefit of aquatic biota. n Table 8-10 Flow percentiles Glenelg River Reach 3 (Summer: December-May inclusive). Site 10% 20% 30% 40% 50% 60% 70% 80% 90% Sandford 642.5 363.6 246.5 189.5 149.8 115.8 72.6 45.2 10.9 Dartmoor 864.9 493.4 343.1 269.7 215.5 158.6 119 82.9 54.7

Per c ent i le Pl o t F r eq uen cy Plo t 450

45 Scen ar io 1

d 400 l o

h 40 s

e 10 .0 % 350 r s r h a

t 2 5. 0%

35 e

e 5 0. 0% y

300 v 0 o 7 5. 0% 30 0 b 1 a 90 .0 %

250 r ) e s

25 p y

a y d 200 ( c

20 n n e o u i q

t 150 a e

15 r r u F d

100 l

l 10 e p

S 50 5

0 0 216 216 T hr esh ol d ( ML ) Th re sh o l d (M L ) n Figure 8-20 Spell analysis Glenelg River Reach 3 at Site 8 (Dartmoor), spells greater than threshold (21 ML/day) (Summer: December – May inclusive).

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 63 The minimum winter flow is recommended to be 629 ML/day. This flow is aimed at providing connectivity through the major habitats in the system, subsequently wetting a large portion of the stream channel (Table 8-12). The minimum winter flow acts as a base from which larger flows such as the high flows or freshes develop. The abundance of large woody debris in this reach will be inundated under such flow and lead to increased submersed habitat complexity.

The spring freshes are targeted to act as biological cues for the biota that occur in Reach 3. These freshes would have occurred naturally on average 2.5 times annually (Figure 8-21), the recommendation is for the average to be between 2 – 3 times annually. Naturally 75% of the events would have lasted for 5 days, and the recommendation is for this to be the minimum duration of the freshes.

Per cent i le Plo t F r equ en cy Pl ot 80 Scen ari o 1 d

l 250 o

h 70 s

e 10 .0% r s h r

t 2 5.0 % a

e 200

e 5 0.0 % y v

o 7 5.0 % 0 b 0

a 50 90 .0% 1

) r s 150 e y p a

40 d y ( c n n e o

i 30

u 100 t q a r e r u F d

20 l l

e 50 p

S 10

0 0 2200 2200 T h resh ol d (M L ) T hr esho l d ( ML ) n Figure 8-21 Spell analysis Glenelg River Reach 3 at Site 8 (Dartmoor), spells greater than threshold (2200 ML/day) (Winter: July – October inclusive). The high flow recommendations of greater than 2200 ML/day will have a key benefit for the freshwater section of this reach providing a significant disturbance and sediment mobilisation. In addition, there are substantial benefits to the estuarine section of the Heritage Reach of the river from the high flows. One of the key threats to the tidal reach is the lack of flushing because of the reduced flows in the river. The high winter flow event will increase the large flushing flows through the tidal reach. The implementation of this recommendation is not a high priority, relative to the minimum flows and freshes. It is likely that large events will be beyond the control of extractions and regulating structures and occur on a more natural frequency. n Table 8-11 Flow percentiles Glenelg River Reach 3 (Winter: July-October inclusive). Site 10% 20% 30% 40% 50% 60% 70% 80% 90% Sandford 8693.0 5290.1 3472.4 2577.3 1984.6 1440.0 1042.7 711.1 417.1 Dartmoor 11946.4 7238.0 4743.7 3493.8 2681.3 2047.1 1476.0 926.8 531.9

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 64 n Table 8-12 Maximum water depth for each cross section at each recommended flow Reach 3 – Wannon River to Tidal Extent. Cross Flow Minimum Water Water Depth Flow Area Water Section ML/day Channel Surface (m) (m 2) Surface Elevation Elevation (m) Width (m) 1 83 -0.45 0.76 1.21 6.96 9 1 216 -0.45 0.95 1.4 8.7 10.05 1 2200 -0.45 2.15 2.6 27.27 21.05 1 629 -0.45 1.34 1.79 13.44 13.98

2 83 -0.25 0.76 1.01 6.83 12.94 2 216 -0.25 0.94 1.19 9.34 15.03 2 2200 -0.25 2.12 2.37 31.55 21.45 2 629 -0.25 1.32 1.57 15.77 18.14

3 83 0.5 0.67 0.17 0.95 9.04 3 216 0.5 0.77 0.27 2.11 15.07 3 2200 0.5 2 1.5 27.3 24.04 3 629 0.5 1.2 0.7 9.7 19.67

4 83 -0.86 0.54 1.4 12.25 13.26 4 216 -0.86 0.76 1.62 15.27 14.46 4 2200 -0.86 1.9 2.76 36.25 21.44 4 629 -0.86 1.15 2.01 21.48 17.5

5 83 0.03 0.53 0.5 2.14 8.63 5 216 0.03 0.74 0.71 5.12 18.07 5 2200 0.03 1.86 1.83 28.88 23.35 5 629 0.03 1.13 1.1 12.73 20.56

6 83 -0.05 0.41 0.46 2.99 11.49 6 216 -0.05 0.62 0.67 5.72 13.78 6 2200 -0.05 1.78 1.83 31.57 30.19 6 629 -0.05 1.04 1.09 12.45 19.36

Glenelg Plan: Site 8 - dartmoor Legend

WS PF 3 Ground Bank Sta

n Figure 8-22 Plan View Site 8: Glenelg River at Dartmoor, Reach 3.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 65 Cross Section: 1 54H 0525093 Cross Section: 2 54H 0525092 UTM 5802697 UTM 5802692

10 10

8 8

6 6

4 4

2 2

0 0 0 20 40 60 80 100 0 20 40 60 80 100 -2 -2

Cross Section: 3 54H 0525073 Cross Section: 4 54H 0525041 UTM 5802641 UTM 5802614

10 10

8 8

6 6

4 4

2 2

0 0 0.0 20.0 40.0 60.0 80.0 100.0 0.0 20.0 40.0 60.0 80.0 100.0 -2 -2

Cross Section: 5 54H 0525020 Cross Section: 6 54H 0524979 UTM 5802620 UTM 5802562

10 10

8 8

6 6

4 4

2 2

0 0 0.0 20.0 40.0 60.0 80.0 100.0 0.0 20.0 40.0 60.0 80.0 100.0 -2 -2

n Figure 8-23 Cross Sections Site 8: Glenelg River at Dartmoor. For each flow recommendation for Reach 3, there are a series of risks associated with not meeting the respective recommendation. Subsequently, these recommendations have been prioritised based on the level of risk to the aquatic environment of not being met (Table 8-13), which do not necessarily correspond to the relative increases in flow magnitude. The first priority for Reach 3 is the maintenance of a minimum summer flow to maintain suitable conditions. If this flow is not met, water quality would be compromised to the detriment of small bodied fish and the benthic community. The flow recommendations with the lowest priority for implementation is the winter high flow of 2200 ML/d. If this flow recommendation is not met, there is likely to be a lack of diversity in channel form and subsequently aquatic habitat. In addition, the lack of a flow of such magnitude would lead to a loss of benthic community diversity and a build up of sand in the channel.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 66 n Table 8-13 Priority for implementation of flow recommendations for Reach 3, indicating risk of not meeting respective recommendations.

Season Magnitude Priority Risk if not met

Summer Minimum A Adverse water quality conditions and low availability of aquatic habitat that (Dec – May) 83 ML/d may lead to deleterious effects on small bodied fish and the benthic community Summer >216 ML/d C Adverse water quality conditions and low availability of aquatic habitat that (Dec – May) may lead to deleterious effects on small bodied fish Winter Minimum B Not mimicing natural flow variability as well as adverse water quality conditions (Jul – Oct) 629 ML/d and limited availability of aquatic habitat Winter >2200 ML/d D Lack of recruitment of many fish species and a reduction in water quality (Jul – Oct) conditions to the detriment of aquatic species. Also lack of diversity in channel form and subsequently aquatic habitat. Also loss of benthic community diversity and a build up of sand in the channel

8.2 Supporting recommendations While site-specific flow bands are in themselves important, our recommendations also consider longitudinal and lateral connectivity issues and tributary inflows. We recognise that not all flow peaks were naturally conveyed down the length of the channel, so not all freshes recommended in upper sections are included in the lower reaches. Hence, our recommendations for lower reaches allow for travel times and attenuation of flows as water is moved downstream through the system.

The additional water introduced to the system from the various confluences is a major factor in our recommendations and affects the timing and magnitude of any of the flow components in downstream reaches.

The value of managing summer flows in the river is limited if the peaks in flow caused by freshes are taken off along the way and not allowed to flow through the system to lower reaches. These flows are vital to ease the summer stress that the low-flow condition imposes on the instream ecosystem. Even small flows can freshen up pools and provide some opportunity for movement into other habitats that are possibly less stressed or less utilised by competitors.

Lateral connectivity issues are also complicated in the Glenelg River. Although there are real management issues associated with recommending higher flows, connectivity with a degraded riparian zone may be of limited ecological value. Two main issues require attention throughout the catchment: better management of stock access (through fencing) to the stream margins and better weed management throughout the riparian zone.

Lateral connectivity also relates to connectivity to the local groundwater. In the case of the Glenelg River, water quality in the mid reaches is adversely affected by saline groundwater returns. Catchment management of irrigation techniques and vegetation cover often quite remote to the stream will be required to manage groundwater interception.

Finally, we cannot recommend strongly enough, the need for ongoing monitoring of the implementation of our recommendations. There is no easily prescribed recipe for returning natural values to impacted streams and our recommendations must be carefully scrutinised and adapted, as appropriate. Streams are dynamic parts of the

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 67 landscape that demand equally dynamic management. All recommendations listed here rely on the information available at the time of writing. This information will change and should be monitored to allow an adaptive management regime of the system into the future.

In summary the series of key supporting recommendations include:

1) Monitor the implementation of the recommendations and adapt where appropriate

There is a range of monitoring components that should be considered, including: q As the summer and spring freshes are implemented, physical monitoring of key water quality parameters (dissolved oxygen, temperature and electrical conductivity) should be monitoring on a regular frequency at stages downstream. For example, ongoing monitoring in Reach 2 to assess changes in saline pools formation, the impact of cease to flow events and freshes is critical. q Recruitment of key fish species is a suggested indicator for several flow components this requires ongoing monitoring to understand what the limiting factors for recruitment are in the system. q Within the Glenelg River, sand accumulation and its effect on channel structure and habitat diversity are key issues. Large flows have been recommended that should mobilise sediments through the system. The efficacy of the large flows recommended should be monitored to determine if sand is moving and where it is accumulating. This could be used to target sand extraction activities. q To validate the assumptions used in the development of the recommendations, depth monitoring at the cross-sections should occur during implementation of the flow components to check the assumptions and accuracy of the flow benefits. The tables have been provided that specify the maximum depth of water for each cross section at recommended flows. q An integrated monitoring program to assess the changes and benefits of the environmental flow releases should be designed and implemented as soon as possible. This program should integrate water quality and biological indicators through the system and build on the work by Brad Mitchell and Deakin University.

2) Monitor the impact of future extractions within the catchment

Currently there are relatively small levels of extractions from the Glenelg River, excluding Rocklands and Moora Moora Reservoirs. Any further extractions through pumping or farm dams should be closely monitored.

3) Examine the removal of fish barriers

The highest priority fish barrier has already been removed from the Glenelg River, the remaining identified barriers are the series of fixed crest weirs near Balmoral. These barriers should be removed when appropriate in line with the state fishway strategy

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 68 (DNRE 1999). In addition, the feasibility of improving the movement of fish beyond Rocklands Reservoir.

4) Fencing and stock control of stream length

This is an ongoing program as part of the waterway planning process. To manage bed and bank structure with flows, external influences such as stock access require control.

5) Weed control

This action is also supported by the catchment plan and waterway plans. Weed management will enhance the benefits as a result of the implementation of environmental flows.

6) Manage inputs of saline water into the lower reaches

This is a key catchment action that will remove the requirement of large flushing flows to ameliorate saline pool effects. Until these actions have been undertaken, recommendations into summer cease to flow would not be implemented.

7) Examine impact of cold water releases downstream of Rocklands Reservoir

This is a key study that is beyond the scope of the current study but would build upon the current results. Rocklands Reservoir is deep enough and has a bottom release outlet to consequently be a substantial source of cold water effects in the mid reaches of the Glenelg River. Cold water released from Rocklands Reservoir may have a significant effect on the community structure or reproductive capacity of the populations, reducing potential benefits of the environmental flow releases for this reach. A study should examine the potential impacts of the Rocklands Reservoir releases and determine if they would limit the environmental flow benefits in the system.

8) Examine potential sand extraction sites

As discussed in previous strategies sand extraction is likely to be the only method of removing significant amounts of sand from the Glenelg River. High flows will move sand down this system, but this is just likely to transfer the problem. The best option would be to extract sand directly from several sites to increase the efficacy of the high flows recommended.

9) Areas of bank stabilisation

The stabilisation of stream banks is important to reduce erosion and hence encourage the establishment of native fringing vegetation and reduce input of sediment into the river. Unstable banks can also lead to lateral expansion of the river channel that result in the reduction of the velocity of flows down the system as the same volume of water is spread over a larger area. Bank stabilisation practices linked with fencing of the riparian zone can encourage the regrowth of vegetation, hence improving water quality and instream habitat.

10) Install/Reactivate Gauges for Compliance Points

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 69 Environmental flow recommendations have been developed to be gauged at particular compliance points throughout the system, specifically streamflow gauging sites. However, in the Glenelg River, these streamflow gauges are not at the most appropriate site or the collection of records has ceased. It is therefore recommended that the gauge at Harrow (238 210) be reactivated in order to gauge compliance in Reach 1. In addition, due to the lack of a suitable compliance point toward the lower end of Reach 2, it is recommended that a gauge be established at Warrock Road at Roseneath. Until this gauge is established, the gauge on the Glenelg River at Dergholm (238 211) should be utilised.

11) Reintroduce snags in areas of mid reaches where desnagging has occurred

Extensive desnagging has occurred in certain areas of the mid reach of the Glenelg River. Habitat is a key factor in community maintenance and large woody debris (snags) has been identified as a key habitat type in the aquatic ecosystem. Habitat improvement through resnagging will assist in maximising the benefits of flow regime improvements.

12) Investigate limitation of outlet capacities

The current capacity and operation of releases from outlets into the Glenelg River may limit the ability to provide adequate environmental flows into the main stem of the river. Releases from Rocklands Reservoir are currently capped at 35 ML/d due to greater flows resulting in flooding at Fraser’s Swamp. Secondly, releases from both the 5 Mile and 12 Mile outlet channels are limited to 20 ML/d due to the clogging up of carp screens with debris at flows in excess of this magnitude. These carp screens have been set in place to limit the distribution of this species throughout the system and require substantial labour to clean the screens of debris. In addition, as the screens clog up, the volume of water being released at the outlets is reduced as less water passes through the screens.

The valve capacity at Rocklands Reservoir is 600 ML/day, the volume of water that is released to the river can be further reduced depending on the demand for water through the Toolondo channel. Consequently there are issues as to how some of the large flows (e.g. > 1400 ML/day) may be released in the current infrastructure.

Therefore to utilise these outlet points to provide environmental flows in the most efficient and reliable way will require further investigation.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 70 9. References

ANZECC (2000). ANZECC List of Threatened Vertebrate Fauna. The Australian and New Zealand Environment Conservation Council, Canberra. Bird, E.C.F. (1977). Sites of special scientific interest in the Victorian coastal region. A report on geological and geomorphological aspects prepared for the Town and Country Planning Board. Bird, J.F. (1985). Review of channel changes along creeks in the northern part of the Latrobe River basin, Gippsland, Victoria, Australia. Zeitschrift für Geomorphologie Supplement Band, 55: 97-111. Brizga, S.O., N.M. Craigie, P. Condina and Lawson and Treloar Pty Ltd (2000). Development of operational guidelines for sand management sites on the Glenelg River: Feasibility study. Final report to the Glenelg Hopkins Catchment Management Authority. Brooks, A.P. and G.J. Brierley, (1997). Geomorphic responses of the lower Bega River to catchment disturbance, 1851-1926. Geomorphology, 18: 291-304. Burston, J. and M. Good, (1996). The impact of European settlement on erosion and sedimentation in the Inman River catchment, South Australia. In I.D. Rutherfurd and M. Walker (eds.), Stream Management ’96, Proceedings of the First National Conference on Stream Management in Australia, Merrijig. Cooperative Research Centre for Catchment Hydrology, Melbourne: 259-64. Cameron, M. and Jekabsons, M. (1992). Salinity in the Glenelg and Wannon Rivers, Victoria. Department of Conservation and Natural Resources, Victoria, Davidson, N., Jeffery, G., and Wagg, C. (1994). The Environmental Condition of Streams in the Glenelg Basin. Department of Conservation and Natural Resources and National landcare Program, Victoria, Dixon, P.R., Wagg, C., and Amirtharajah, M. (1998). Aspects of Environmental Conditions in the Glenelg-Hopkins Region with Particular Reference to Salinity and Nutrients in Rivers, Wetlands and Remnant Vegetation. Department of Natural Resources and Environment, DNRE (1997). Heritage rivers and natural catchment areas. Draft management plans Volume 1 - Western Victoria. Department of Natural Resources and Environment, East Melbourne. DNRE (1997a). Victoria's Environmental Flow Program. Department of Natural Resources and Environment. DNRE (1999). State Fishway Program - an inventory of fishways and potential barriers to fish movement and migration in Victoria. Department of Natural Resources and Environment, Waterways Unit. DNRE (2000a). Atlas of Victorian Wildlife. Arthur Rylah Institute - Department of Natural Resources and Environment, Heidelberg. DNRE (2000b). Threatened vertebrate fauna in Victoria - 2000. Department of Natural Resources and Environment, East Melbourne. DNRE (2000c). Victorian Aquatic Fauna Database. Arthur Rylah Institute - Department of Natural Resources and Environment, Heidelberg. DWR (1989). Water Victoria: a Resource Handbook. Victorian Government Printing Office, Melbourne. EPA (1999). The health of streams in the Glenelg catchment. River Health Bulletin. Environment Protection Authority, Victoria. Erskine, W.D. (1994). River response to accelerated soil erosion in the Glenelg River catchment. Australian Journal of Soil and Water Conservation 7: 39-47.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 71 Godoy, W. (1996). The Effects of Rocklands Reservoir on the Glenelg River. Department of Natural Resources and Environment - Water Bureau, July 1996. GRCLPB (1997). Glenelg Regional Catchment Strategy. Glenelg Regional Catchment and Land Protection Board, May 1997. Hart, B.T. (1982). Water quality: formulation of criteria. In: O'Loughlin, E.M. and Cullen, P. (Eds) Predictions in Water quality. Australian Academy of Science, Canberra, pp 11-26. Ingeme, Y. (1996). Glenelg River Catchment Environmental Flows Technical Report - Draft Report. Department of Natural Resources and Environment, July 1996. Koehn, J. D. and O'Connor, C., W.G. (1990). Biological information for the management of native freshwater fish in Victoria. Government Printer, Melbourne. LCC (1991). Glenelg River - Victorian heritage river. Rivers and streams special investigation - final recommendations. Report extract. Land Conservation Council, Victoria. McGuckin, J.T., Anderson, J.R., and Gasior, R.J. (1991). Salt Affected Rivers in Victoria. Arthur Rylah Institute for Environmental Research, July 1991. Mitchell, B., Rutherfurd, I., Constable, A., Stagnitti, F., and Merrick, C. (1996). An Ecological and Environmental Flow Study of the Glenelg River from Casterton to Rocklands Reservoir. Aquatic Resource Utilisation and Management Research Group, Deakin University, Warrnambool. August 1996. Mitchell, P. (1990). The Environmental Condition of Victorian Streams. Department of Water Resources, Victoria. OCE (1988). State of the environment report 1988. Victoria's inland waters. Office of the Commissioner for the Environment, Victoria. Pollard, D.A. (1971). The biology of a landlocked form of the normally catadromous salmoniform fish Galaxias maculatus (Jenyns). I. life cycle and origin. Australian Journal of Marine and Freshwater Research 22: 91-123. Prosser, I.P., I.D. Rutherfurd, J.M. Olley, W.J. Young and P.J. Wallbrink, in press. Patterns and processes of erosion and sediment transport in Australian rivers. Marine and Freshwater Research. Rutherfurd, I.D. and Budahazy, M. (1996). A Sand Management Strategy for the Glenelg River and its Tributaries, Western Victoria. Report to the Department of Natural Resources and Environment, Victoria and Southern Rural Water. Cooperative Research Centre for Catchment Hydrology, Report 96/9, Melbourne. Melbourne. December, 1996. Ryan, T. and Davies, P. (1996). Environmental effects of salinity and nutrients from salt disposal: approaches to the development of management criteria. Flora and Fauna Technical Report 137. Department of Natural Resources and Environment. SKM (2001a). Glenelg River Environmental Flow Study. Issues Paper. Report to the Glenelg Hopkins Catchment Management Authority. Sinclair Knight Merz. SKM (2001b). Glenelg River Natural Flow Estimation. Report to the Department of Natural Resources and Environment. Sinclair Knight Merz. Schlosser, I.J. (1982). Fish community structure and function along two habitat gradients in a headwater stream. Ecological Monographs 52: 395-414. Schreiber, E.S.G., Wagg, C., Metzeling, L., and Perriss, S. (1998). Assessing stream health in the Glenelg catchment - using macroinvertebrates. Department of natural Resources and Environment and Environment Protection Authority, Sherwood, J., Magilton, C. and Rouse, A. (1998). The Glenelg River: Nutrient and Estuarine Hydrodynamics. Deakin University, Warrnambool. July 1998.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 72 Wagg, C. (1997). A Summary of the Water Quality in the Glenelg Catchment. Department of Natural Resources and Environment, Walker, K.F., Thoms, M.C., and Sheldon, F. (1992). Effect of weirs on the littoral environment of the River Murray, South Australia. Pages 270-293 in Boon, P. J., Calow, P. A., and Petts, G. E., eds. River Conservation and Management. Wiley, Chichester.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 73 Environmental Flow Study of the Glenelg River System

PART B

Issues Paper

Final

April 2001

This document was completed in Stage 1 of the project. It was approved by the Glenelg Hopkins CMA and formed the basis for Stage 2 of the project.

590 Orrong Road Armadale VIC 3143

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 the Sinclair Knight Merz constitutes an infringement of copyright. Contents

1. Introduction...... 1 1.1 Project scope ...... 1 2. Catchment description...... 2 2.1 Physiography ...... 2 2.2 Landuse ...... 6 2.3 Hydrology ...... 7 2.4 Water quality ...... 10 2.4.1 Salinity...... 10 2.4.2 Dissolved oxygen...... 11 2.4.3 Nutrients ...... 11 2.4.4 pH...... 11 2.4.5 Turbidity...... 11 2.5 Biota ...... 12 2.6 Summary...... 14 3. Key issues...... 16 3.1 Potential environmental issues ...... 16 3.2 Sand slugs ...... 19 3.3 Water quality ...... 20 3.4 Regulation ...... 22 3.5 Channel condition ...... 24 3.6 Current flora and fauna values of the Glenelg River system ...... 25 3.7 The heritage reach...... 26 4. Methods...... 28 5. Site descriptions...... 31 6. Objectives...... 37 6.1 Policy and strategy objectives ...... 37 6.2 Catchment objectives ...... 38 6.3 Environmental objectives...... 38 7. Discussion...... 40 7.1 Seasonal timing of releases ...... 40 7.2 Periods of cease to flow ...... 41 7.3 Baseflows ...... 41 7.4 Freshes during periods of cease to flow/low flow ...... 41 7.5 Spring freshes...... 42 7.6 Flow variability...... 42 7.7 High flows ...... 42 8. Recommendations...... 43 8.1 Flow Recommendations ...... 44 8.1.1 Reach 1 – Rocklands Reservoir – Chetwynd River...... 44 8.1.2 Reach 2 – Chetwynd River to Wannon River ...... 52 8.1.3 Reach 3 – Wannon River to Tidal Extent ...... 61 8.2 Supporting recommendations ...... 67 9. References ...... 71 1. Introduction...... 1

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE i 1.1 Project scope ...... 1 1.2 Report structure...... 2 2. Catchment description...... 3 2.1 Physiography ...... 3 2.2 Landuse ...... 3 2.3 Hydrology ...... 7 2.4 Water quality ...... 10 2.4.1 Salinity...... 10 2.4.2 Dissolved oxygen...... 11 2.4.3 Nutrients ...... 11 2.4.4 pH...... 11 2.4.5 Turbidity...... 12 2.5 Biota ...... 12 2.6 Summary...... 14 3. Key issues...... 16 3.1 Potential environmental issues ...... 16 3.2 Sand slugs ...... 19 3.3 Water quality ...... 20 3.4 Regulation ...... 22 3.5 Channel condition ...... 23 3.6 Current flora and fauna values of the Glenelg River system ...... 24 3.7 The heritage reach...... 25 4. Environmental objectives...... 27 Preliminary umbrella objectives ...... Error! Bookmark not defined. 4.2 Preliminary specific objectives ...... 27 5. Outcomes...... 28 5.1 Assessment framework...... 28 5.1.1 Technical panel...... 28 5.1.2 Study reaches ...... 28 5.1.3 Use of existing data and information...... 30 5.2 Reporting...... 30 6. References ...... 31 Appendix A Hydrology...... 34 A.1 Streamflows...... 34 A.2 Licensed water use...... 36 A.3 System operation...... 37 A.4 Summary...... 38 A.5 Flow plots ...... 39 A.6 Flow duration curves...... 42 A.7 Rocklands Reservoir Discharge...... 54 Appendix B Geomorphology...... 55 B.1 Introduction ...... 55 B.2 Stream network...... 55 B.3 Hydrology ...... 56 B.4 Landuse ...... 56 B.5 Sand slugs ...... 57 B.6 Summary...... 58 Appendix C Water quality...... 59

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE ii C.1 Salinity...... 60 C.2 Nutrients ...... 61 C.3 pH...... 62 C.4 Dissolved oxygen...... 63 C.5 Turbidity...... 63 C.6 Summary...... 64 C.7 Water quality plots indicating guideline values ...... 65 Appendix D Biota 77 D.1 Condition of instream and riparian habitat...... 77 D.2 Fish, decapod crustacea and molluscs...... 77 D.2.1 Fish ...... 77 D.2.2 Decapod Crustacea ...... 82 D.2.3 Macroinvertebrates ...... 82 D.3 Birds ...... 83 D.4 Amphibians and reptiles ...... 83 D.5 Other vertebrates ...... 84 D.6 Instream and riparian flora...... 85 D.7 The Glenelg Heritage River and Lower Glenelg National Park...... 86

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE iii Document History and Status

Issue Rev. Issued To Qty Date Reviewed Approved 1 Draft Melanie Tranter 1 15/02/01 Brenton Zampatti (ARI) Michael Shirley (GHCMA) 2 Draft Melanie Tranter 1 23/02/01 Melanie Tranter Michael Shirley (GHCMA) (GHCMA) Glenelg Project Group John Martin (WMW) 3 Draft Alex Marshall (GHCMA) 1 2705/01 Glenelg Project Group Michael Shirley 4 Final Alex Marshall (GHCMA) 1 7/06/01 Alex Marshall (GHCMA) Michael Shirley

Printed: 7 May, 2003 Last Saved: 15 October, 2002 File Name: I:\WCMS\Wc01432\500_Analysis_Reporting\Reporting\Released Reports\Revised\R04_Mjs_Glenelg_Final.Doc Project Manager: Michael Shirley Name of Organisation: Glenelg Hopkins Catchment Management Authority Name of Project: Wimmera, Avoca and Glenelg Environmental Flows Name of Document: Glenelg River issues paper Document Version: Final Project Number: WC01432

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE iv 1. Introduction

Reducing or altering streamflows can have dramatic impacts on the health of riverine ecosystems with subsequent implications for other water users. Flow is the governing influence in rivers, controlling many aspects of the physical environment and significantly affecting the biota of a riverine system. It is, therefore, essential that adequate water be provided for the purpose of protecting the physical and ecological processes and features of rivers.

The need to reform the water resource industry and provide water for the environment has been recognised by both Federal and State Governments in the Council of Australian Governments’ (COAG) Water Reform Agenda (ARMCANZ, 1995). Under the 1994 COAG agreement, the environment is recognised as a legitimate water user and environmental water requirements must be assessed and provided. The National Principles for the Provision of Water for Ecosystems define environmental water requirements as:

…the water regimes needed to sustain the ecological values of aquatic ecosystems at a low level of risk (ARMCANZ and ANZECC 1996).

Given that some systems are over-allocated and unable to provide fully for environmental water requirements, negotiation between stakeholders can lead to the establishment of flows for the purpose of environmental protection. Such flows are defined in this report as environmental water provisions, meaning:

…that part of environmental flow requirements that can be met (ARMCANZ and ANZECC 1996).

The Department of Natural Resources and Environment has developed the Victorian Water for the Environment Program to implement measures in place to provide water to meet environmental needs. The shared objective of this program to increase environmental flows is to maintain and, where possible, restore the environmental values of rivers and wetlands, whilst recognising existing entitlements. The program includes a two-stage process for providing water for the environment: 13) protecting and enhancing environmental flows through water entitlement agreements; and 14) rehabilitating stressed river systems (DNRE 1997a).

1.1 Project scope The Glenelg River was identified as the highest priority river for restoration as part of the Victorian Stressed Rivers Programs. The current study was consequently developed to address the key flow related issues in the Glenelg River system, specifically the environmental water requirements of the surface water systems of the Glenelg River catchment.

The aim of this project is to provide a scientific basis for the implementation of environmental flow provisions for water dependent ecosystems of the Glenelg River. The project requires a multi- disciplinary approach, with a need to integrate information from ecology, hydrology, geomorphology, and water quality.

The project defines a clear scientific process for the determination of environmental water requirements and strategies to implement and test the efficacy of the environmental water provisions that are implemented. The project will include: q investigation of existing information on key flow related issues; q definition of multi-disciplinary objectives and targets; q use of a sound scientific method to define the environmental water needs;

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 1 q develop recommendations for monitoring to support and measure the implementation of environmental water provisions.

The project will be conducted in two stages. In Stage 1, the current environmental status of the catchment will be examined. This includes examination of the current system operation, aquatic ecology, hydrology, geomorphology and water quality conditions. Information will also be sought on current and future threats to the ecological and biodiversity values of the catchment, as related to water management. The current management arrangements and the implications of these for the Glenelg River and water dependant ecosystems will also be determined. This stage also aims to clarify specific objectives and required project outcomes. Some ground-truthing of the information gathered through Stage 1 will underpin the selection of key areas, study reaches and issues for further targeted investigation. This information will enable the selection of the most appropriate method for the determination of environmental water requirements, and the refinement of the detailed work plan for subsequent stages of the project. This report is the output of Stage 1.

Recommendations for the environmental water requirements of the Glenelg River are developed in Stage 2. This is discussed in more detail in Section 5 of this report.

1.2 Report structure As part of Stage 1, a series of preliminary Issues Papers were produced to review available information on the environmental status of the catchment according to discipline categories including ecology, hydrology, geomorphology and water quality. Information in the preliminary Issues Papers was verified via comments from the Project Group, discussion with Brad Mitchell of Deakin University, Project Steering Committee and during a field inspection of the catchment in September 2000 by Bruce Abernethy and Paul Close.

The project is now at the completion of Stage 1 and the preliminary Issues Papers (see appendices) together with information obtained during a field inspection by the team have been used to produce this Integrated Issues Paper. This paper identifies and reviews the available background information on the values and issues in the catchment and river system, assesses critical knowledge gaps and considers key issues for consideration in developing an approach to determining the environmental water requirements of the Glenelg River.

This document reports on an audit of available information, undertaken to identify the ecological, hydrological and geomorphological values and flow related issues in the Glenelg River catchment. Section 2 describes the Glenelg River catchment in terms of its geomorphology, landuse, hydrology, water quality and biota. Section 3 provides an overview of the key issues that are apparent in the catchment and comment on how they relate to environmental water management. Section 4 identifies flow-related environmental objectives for the Glenelg River while Section 5 provides a framework for further work required to determine the river’s environmental water requirements. Detailed issues papers are appended at the end of the document.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 2 2. Catchment description

The study area specified for this report is the main channel of the Glenelg River. No tributaries are included in the study area.

2.1 Physiography The Glenelg River rises in the Grampians and flows to the Southern Ocean (Figure 2-1 Glenelg River catchment.). On leaving the Grampians the river flows along the northern and then the western edge of the Dundas Tablelands, between Rocklands Reservoir and Casterton. Near Casterton the Wannon River joins the Glenelg River and from there the Glenelg River meanders across broad coastal plains towards Dartmoor. Below Dartmoor the river follows a generally southerly course becoming increasingly incised in limestone (Erskine 1994). At the confluence of Moleside Creek the river turns WNW and runs parallel to the coast, eventually looping into South Australia before entering the sea at Nelson.

Davidson et al. (1994) suggested that flow regulation, sedimentation, salinisation and extensive snag removal were the main factors leading to poor channel condition. Our field observations support those of Mitchell et al. (1996) that the riparian vegetation is continuous to discontinuous along both banks of the river but is generally restricted to the bankface and the immediate bank verge (Figure 25, Figure 26). The lower section in the Lower Glenelg National Park is in good condition with excellent bank and verge vegetation (Figure 29). The banks are generally stable with only isolated examples of bank erosion (Figure 42). In some locations, bank instability is associated with stock traffic.

The main issue associated with physical condition of the Glenelg River is the high sand load that occupies a large proportion of the channel (Figure 43). The sediment has created a sandy bed with and reduced the occurrence of deep holes (>2m) in sections of the river. Areas of sediment build-up are most obvious are around Casterton and Harrow.

2.2 Landuse The Department of Water Resources Victoria (1989) reports that European settlement of the Glenelg catchment began in 1837. The merino wool industry was established quickly and today wool is still

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 3 Glenelg Hopkins Catchment Management Authority

n Figure 39: Glenelg River catchment.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 4 n

n Figure 25: Glenelg River at Fulham Hole Streamside Reserve (note typical riparian vegetation, consisting of patchy overstorey and little or no understorey).

n Figure 26: Glenelg River at Dartmoor. the main product of the region with prime lamb production also important. The beef industry is well established and a small amount of dairying occurs in the catchment. Since 1837, two-thirds of the catchment has been cleared for pasture to graze sheep and cattle and today only two main forested

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 5 areas remain. The northeast of the catchment is forested and includes the Grampians National Park, as well as State Forest where a small amount of hardwood is logged. In the west there is a mixture of native hardwood forests (the Glenelg National Park) and intensive softwood plantations (Department of Water Resources Victoria 1989). Hamilton is the major urban centre within the catchment, located in the southeast.

n Figure 42: Glenelg River at Wannon River confluence (note erosion of left bank).

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 6 n

n Figure 43: Sand slug in the Glenelg River downstream of Chetwynd River confluence.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 7 n

n Figure 29: Lower Glenelg River.

There are three notable water storages within the Glenelg River basin. These are Konong Wootong Reservoir, Moora Moora Reservoir, and Rocklands Reservoir. Konong Wootong is a small reservoir constructed on Den Hills Creek, a tributary of the Wannon River, to supply the townships of Casterton and Coleraine. The capacity of this storage is 1,920 ML and diverts approximately 852 ML/year out of the system (Ingeme 1996). Moora Moora Reservoir is located in the upper reaches of the Glenelg River. The reservoir is a small, offstream storage with a capacity of only 6,300 ML (Department of Water Resources Victoria 1989). Lake Bellfield diverts water from the upper Wannon River. Rocklands Reservoir is the largest storage in the catchment with a total capacity of 348,000 ML. The primary purpose of the storage is to provide domestic and stock supply to the Wimmera Mallee Water channel system (Godoy 1996).

Rocklands Reservoir has a significant impact on the seasonal flow pattern downstream of the reservoir, although the impact decreases with distance from the dam. Rocklands has a storage capacity about three times its average annual inflow and has spilled once every four years on average since construction. Downstream of Chetwynd River, flows are continuous due to natural inflow from the catchment adding to the river flows and current releases from the reservoir do not appear to exert an influence below Casterton (Mitchell et al. 1996). Recent observations in December 2000 have shown that this section of the Glenelg River did cease to flow (M. Tranter pers. comm.)

The Glenelg River, under natural conditions, commonly ceased to flow at Balmoral over the three months February to April, sometimes for months longer (Godoy 1996). The deep pools through the river would have allowed the key biota to persist during the cease to flow periods. However, the cease to flow does not occur within the current flow regime, which is a summer autumn flow release. Under low flow conditions transit times for releases from Rocklands Reservoir are approximately 7 days to Balmoral, 14 days to Fulham Bridge and 21 days to Harrow. According to Mitchell et al. (1996) a 20- 25 ML/day release at Rocklands delivers 10 ML/day at Fulham Bridge and 2 ML/day at Harrow.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 8 The total licensed volume for water extraction from the main channel of the Glenelg River is 68.2 ML/year which is a very small proportion of licensed water entitlement in the Glenelg River system (Table 6-1). All licences on the Glenelg River extract upstream of the Wannon River confluence (J Donovan, pers. comm.). An additional 878.6 ML/year is licensed for extraction from the remainder of the catchment. Of the 68.2 ML/year available for extraction from the Glenelg River, 66 ML/year is extracted through two irrigation licences. These licences are generally used sometime between September and February, although the specific timing of such use is dependent on the crops being irrigated. The remaining 2.2 ML/year is a dairy licence, which is used throughout the year for dairy washing and stock watering.

The Rocklands Outlet channel passes from Rocklands Reservoir in the Glenelg River Basin to Toolondo Reservoir in the Wimmera Catchment. Water is also lost from the Glenelg River due to evaporation at Fraser’s Swamp and water being held up by the tributary junction plugs that are present in the stream. To reduce losses along the river to Fulham Bridge, Wimmera Mallee Water can release water from the 5 and 12 Mile channel outfalls, although this is generally only done when there are concurrent transfers to Toolondo Reservoir. There is some leakage from the Rocklands Outlet channel that reaches the Glenelg River and helps offset some of the losses in this reach.

A compensation flow from Rocklands Reservoir down the Glenelg River is currently fixed at 3,300 ML/year. This was previously a sliding scale between 2,500 ML and 3,700 ML/year, but at the request of the Glenelg Hopkins CMA, a new formula has been developed being the average of the historic releases, (3,300 ML/year)(Table 2-1)(R Leeson, pers. comm.). Wimmera Mallee Water is required to maintain a reserve volume in Rocklands to guarantee this compensation flow. The compensation flows, released in summer and autumn, are aimed to maintain a target flow of 5-10 ML/d at Fulham Bridge and 1-2 ML/day at Harrow. Commencement of compensation flows is timed to take advantage of the wet river channel and thus prevent the flow from ceasing altogether (Godoy 1996) and the releases to the river are based on the flow measured at Fulham Bridge (Gauge 238224). The compensation flows are generally released between mid November to late April, depending on the weather.

n Table 2-1 Summary of environmental flow releases for the Glenelg River (Source Wimmera Mallee Water) Season Compensation Flow Environmental Flow Total Release ML ML ML 1996-97 3,700 4,119 7,819 1997-98 3,210 6,167 9,377 1998-99 3,300 5,736 9,036 1999-2000 3,300 1,994 5,294

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 9 2.4 Water quality The key parameters that influence ecological processes and water use are salinity, nutrients (TN and TP), pH, dissolved oxygen (DO), and turbidity. For example, low levels of dissolved oxygen can restrict aerobic respiration resulting in stress to or mortality of aquatic biota. Similarly, high nutrient levels can result in algal blooms that make the water unsuitable for consumption.

The VWQMN Annual Report presents attainment values (with the set guideline) for each water quality parameter. Attainment is the frequency (% occurrence) that a particular water quality parameter falls within developed guidelines for a specific site. Attainment values are described as either high (> 95%), moderate (90-95%) or low (< 90%) (AWT 1999).

Water quality data has been assessed for this project at five sites along the river system: q Glenelg River at Big Cord (238231), upstream of Rocklands Reservoir; q Glenelg River at Fulham Bridge (238224), about 20km downstream of Rocklands Reservoir; q Wannon River at Henty (238228), about 15km upstream of the confluence with the Glenelg River; q Glenelg River at Sandford (238202), immediately downstream of the Wannon River confluence; and, q Glenelg River at Dartmoor (238206).

Data from these sites for the years 1990 to 1999, inclusive, are plotted in Appendix C and summarised in Table 6-2 (Appendix C).

2.4.1 Salinity Salinity varies along the length of the Glenelg River, with the structure of the channel and groundwater intrusions characterising different reaches and the resultant impact of salinity. Salinity is probably the key impacting water quality parameter in the Glenelg River system, that is directly impacted by the flow regime.

The section of the Glenelg River between Rocklands Reservoir and Fulham Bridge was characterised by Sherwood et al. (1998a) as shallow sections (<3 m deep) interspersed with deep elongated pools (>8.5 m deep). This section of the river has been identified as a major source of salt. Salinity increases with distance downstream from Rocklands Reservoir through this reach (Sherwood et al. 1998a).

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 10 significant reduction in useable habitat, and also reduce access to the benthos which is a significant source of food and resources. Although stratification and deoxygenation would have occurred naturally in pools, particularly in low flow events, the current reduced flow conditions exacerbate this effect.

2.4.2 Dissolved oxygen Severe deoxygenation has been found throughout the length of the Glenelg River (McGuckin et al. 1991). McGuckin et al. found that deoxygenation was closely associated with the presence of saline pools in the reach from Rocklands Reservoir to Fulham Bridge with each pool registering a bottom dissolved oxygen concentration of less than 10% saturation. Sites between Casterton and Dartmoor were only slightly better than upstream with values ranging between 10-40% saturation. McGuckin et al. suggested that the temperature gradient in this section of the river was most likely associated with the depth of the pool and was the governing factor controlling DO at conductivities less than 500 mS/cm.

Sources of nutrients within the Glenelg River are varied. For example, contrary to the norm, active erosion in the subcatchment of Sandford contributes to total nitrogen (TN) loads but no total phosphorus (TP). Nitrogen may be from decaying organic material and animal wastes. Until 1996/97, the Casterton Wastewater Treatment Plant was contributing an unknown load of nutrients to the river, which would be having a major impact. This practice of discharging has now ceased (Wagg 1997). Septic tank effluent at Dartmoor may also contribute to nitrogen concentrations in the river (Sherwood et al. 1998a). At Dartmoor, TKN associated with organic material is also positively related to flow, similarly for TP, which is attached to sediments (Wagg 1997).

Although TP rarely exceeds the guideline values (see Appendix C) in the Glenelg River, values of TN progressively exceed guideline values with distance downstream. The occurrence of high nitrogen values can potentially lead to the growth of algal blooms.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 11 water was slightly acidic. This indicates that pH is not an issue in terms of water quality in the Glenelg River below Rocklands Reservoir.

2.4.5 Turbidity Median turbidity values have been recorded as excellent for the past 10 years at all sites presented. The 90th percentile values for turbidity at Henty, Dartmoor and Sandford have frequently indicated degraded conditions that correlate with periods of high flow during winter (Department of Water Resources Victoria 1989). Turbidity at Fulham Bridge has been shown to correlate positively with discharge at flows greater than 10 ML/day (Mitchell et al. 1996). Turbidity is not of concern in the Glenelg River system as the high winter turbidity levels are not prolonged and return to acceptable levels.

2.5 Biota The native freshwater fauna of the Glenelg River system represent a diverse assemblage with high conservation significance. As shown in Table 3 (Appendix D), twenty species of native freshwater fish and 26 estuarine species have been recorded from the Glenelg River system (DNRE 2000c). Eight species have conservation significance and of these, five are protected through their listing on the Victorian Flora and Fauna Guarantee Act 1988. Four species are protected through their listing on the List of Threatened Australian Vertebrate Fauna (ANZECC 2000). Of the 20 species of native freshwater fish, seven are known to migrate between freshwater and estuarine/marine habitats at some stage in their life cycle (Koehn and O’Connor 1990).

Seven species of decapod crustacea and at least three species of bivalve mollusc have also been recorded (Table 3, Appendix D). Of these, the Glenelg freshwater mussel (Hyridella glenelgensis) and the western swamp cray (Gramastacus insolitus) are suspected of being rare, with restricted distributions and low abundances (Tarmo Raadik pers. comm.). Consequently, these species may in the near future be rated as highly threatened fauna in Victoria.

The EPA (1999) recorded a total of 86 families of macroinvertebrates from a total of 61 survey sites throughout the Glenelg River catchment (Table 4, Appendix D). Mitchell et al. (1996) and EPA (1999) report a dominance of insects (such as beetles, mayflies and true bugs) in the macroinvertebrate community, as is commonly the case in fresh waters. Based on the macroinvertebrate communities present, the health of sites in the Glenelg River was assessed as good to excellent in both pools and shallow habitats based on ratings presented in OCE (1988). Increased community complexity and abundance of macroinvertebrates was reported at sites with macrophytes and organic debris (Mitchell et al.1996).

There have been 271 species of bird recorded in the Glenelg River of which 50 species have conservation significance either in Victoria or nationally (DNRE 2000a, DNRE 2000b). Of the threatened species, 20 are reliant directly upon the instream environment for their survival (Table 5, Appendix D).

The warty bell frog (Litoria raniformis), has been recorded in the Glenelg catchment and is listed as vulnerable by DNRE (2000b). Two species of threatened reptile, the swamp skink (Egernia coventryi) and tree goanna (Varanus varius), have been recorded from the Glenelg catchment (DNRE 2000a). Although the tree goanna does not directly depend on the riparian environment, such areas often provide the only remaining habitat. It should be noted that the latest recorded sightings of these species date from the early 1980’s.

Other vertebrates present in the catchment and known to depend directly on the instream environment for food and shelter include the platypus (Ornithorhynchus anatinus) and water rat (Hydromys

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 12 chrysogaster). Platypus have been recorded in the Glenelg River near Casterton and Dartmoor and in the vicinity of Fulham Hole. The species has also been recorded in the Wannon River near Coleraine and Hamilton, Mackinnon Creek and Grange Burn (unpublished database Australian Platypus Conservancy; Melanie Tranter pers. comm.). There is no documented distribution information for the water rat.

Of the 63 threatened flora species that occur in the Glenelg River catchment (Table 6, Appendix D), 15 of them rely directly on the instream environment or temporary inundation for their survival (DNRE, 2000; Dale Tonkinson pers. comm.). Thirty species of aquatic and semi-terrestrial macrophyte have been recorded in the mid to upper reaches of the Glenelg River (Mitchell 1996). Species richness within sites ranged from 7-11. Emergent aquatic macrophyte species were dominant and represent between 67 and 100% of species present at sites surveyed.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 13 2.6 Summary The following table provides a summary of the issues on a reach by reach basis.

Reach Geomorphology Flora and Fauna Water Quality Hydrology Headwaters to backwater q q Low flows and sediment deposition in q q of Rocklands Reservoir mid to upper reaches of Glenelg have been shown to promote excessive growth of Typha spp. and Phragmites australis

Rocklands Reservoir to q Sediment buildup q Low flows and sediment deposition in q Salinity increases with distance q 70% of annual flow occurs Aug to Chetwynd River around Harrow mid to upper reaches of Glenelg have downstream from this reach Oct to Wannon been shown to promote excessive q Regulation of Rocklands growth of Typha spp. and Phragmites q For a distance 15km downstream of q Significant impact on streamflows Reservoir is inpart australis Rocklands salinity varies greatly caused by Rocklands and spills responsible for the low between the surface and bottom of the only once every four years transport rate q Rocklands Dam significantly impedes river. upstream movement of migratory fish q Glenelg R used to dry at q 60% loss of capacity species. q Very low Dissolved oxygen and Balmoral Feb to Apr under due to sand slugs at temperature is associated with saline natural conditions but current Harrow and Burkes q A large proportion of high and moderate pools for the above distance conditions do not lead to drying Bridge value with only one sub-reach requiring rehabilitation* q Water lost due to evaporation at Fraser’s Swamp

q There is a significant reduction in peak flows, due to Rocklands Reservoir, down to Casterton

Chetwynd River to q Sediment buildup q Platypus recorded near Casterton q Erosion in the Sandford subcatchment q 70% of annual flow occurs Aug to Wannon River around Casterton contributes to increased nitrogen loads Oct to Wannon q Variegated pygmy perch endemic to q 20% loss of capacity Glenelg catchment and found in reach q Deoxygenated pools present q Continuous streamflow due to due to sand slugs at between Harrow and Strathdownie natural inflows Casterton q A large proportion of this reach is q There is a significant reduction in comprised of moderate value sub- peak flows, due to Rocklands reaches with a similar number but Reservoir, down to Casterton smaller length of high value sub- reaches. Two small sub-reaches requiring rehabilitation occur in this region*

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 14 Reach Geomorphology Flora and Fauna Water Quality Hydrology Wannon River to tidal q 10% loss of capacity q Lower Glenelg National Park in good q High nitrogen due to septic inflows q No licences for extraction in this extent due to sand slugs at condition with excellent bank and verge reach Dartmoor vegetation q Deoxygenated pools present

q Platypus recorded near Dartmoor

q This reach contains a larger proportion of high value than moderate value sub- reaches. There are not any sub-reaches requiring rehabilitation in this reach*

Tidal extent to river mouth q q q q No licences for extraction in this reach

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 15 n Table 3-1: Threatened aquatic and semi-terrestrial flora present in the Glenelg River, and associated seasonally inundated wetlands. Scientific Name Common Name Status 1 Agrostis aemula var. setifolia Gilgai blown-grass v Agrostis avenacea var. perennis Wetland blown-grass k Agrostis billardierei var. filifolia Gilgai blown-grass v Amphibromus fluitans River swamp wallaby-grass V, k Baumea laxa Lax twig-sedge r Dianella callicarpa Swamp flax-lily r Eucalyptus kitsoniana Bog gum R, r Euphrasia scabra Rough eyebright K, e Lobelia beaugleholei Showy lobelia R, r Microtis orbicularis Dark mignonette-orchid v Pneumatopteris pennigera Lime fern e Pterostylis tenuissima Swamp greenhood) V, v Senecio psilocarpus Swamp Fireweed V, v Thelymitra epipactoides Metallic sun-orchid E, e Utricularia violacea Violet bladderwort r 1Abbreviations denote conservation status following (Gullan 1990). Upper-case refers to categories in Australia and lower- case to Victoria. E,e, endangered; V,v, vulnerable; R,r, rare; K,k, uncertain. 3. Key issues

In common with other river basins around Australia, the hydrology of the Glenelg River catchment has undergone substantial change in the past 200 years. Extensive clearing of native vegetation for agriculture has resulted in a number of primary impacts on the Glenelg River such as salinisation, erosion and sedimentation. These modifications to the channel system have been further exacerbated as a result of system regulation by Rocklands Reservoir and water harvesting.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 16 in sheet erosion that delivers sediment to the upper river. Moreover, removal of riparian vegetation in mid to lower reaches of the river has resulted in bank instability and subsequent bank slumping which has contributed to sedimentation and reduced capacity of the channel. These processes reduce instream habitat complexity, an essential requirement for aquatic fauna in that it provides different microhabitats for shelter, spawning, food production etc.

Primary factors resulting in a loss of habitat complexity are: q sedimentation leading to the infilling of pools and smothering of coarse substrates, woody debris and macrophytes q salinisation leading to stratification and subsequent deoxygenation of pool habitats, also potentially the inhibition of aquatic macrophyte growth q river regulation leading to a reduction in the magnitude, frequency and duration of high flows in winter and spring thus diminishing channel flushing (removal of sediment from channel). q desnagging leading to a direct loss of woody substrates

Many of these factors are interrelated and are affected by flow but not alone attributable to the altered flow regime. For example, extensive sedimentation in the Glenelg River (some reaches of stream have lost 80% of their former channel capacity) has occurred as a result of vegetation clearing and erosion. Nevertheless, diminished flows over the winter/spring period result in a lack of flushing of the river channel thus leaving sediment deposited in pools in the upper and mid reaches of the Glenelg River

Salinisation as a result of native vegetation clearing and elevated groundwater levels is a primary environmental issue in the Glenelg River (Mitchell 1996). Salinisation and subsequent stratification occur in deep pools (>2 m) in the Glenelg River. In pools over 3 m deep, stratification is stable, long- lived and reappears 1-2 months after flushing (Mitchell 1996). Conductivity in the Glenelg River is highest during the low flow period between January and March and shows a second increase in June- July attributable to additional salt inputs from “first flush” events (Mitchell 1996). Reduction in the magnitude of natural flows as a result of Rocklands Reservoir may also contribute to salinisation of downstream sites. Saline groundwater intrusion appears to be most pronounced above Fulham Bridge (Cameron and Jekabsons 1992, McGuckin et al. 1991, Mitchell 1996) and results in stable stratification under low to moderate flow conditions.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 17 Direct effects of salinisation may result if salt tolerances of organisms are exceeded, leading to lethal physiological effects. Similarly, increase levels of salt may have sub-lethal effects on stream biota that may result in reduced growth rates, reduce reproductive success and reduced health and vigour.

While the following section considers each of the identified issues as separate phenomena, they are in reality all interlinked. Moreover, their relative importance changes with location within the catchment and though the year. Due to the interaction between issues it is impossible to legitimately rank them relative to each other. Hence, the order in which the issues are described is not one of relative importance within the catchment.

In brief, the five key issues that confront the Glenelg River are as follows. 7. Sand slugs:

– loss of channel form;

– reduced substrate diversity; and

– reduced instream habitat diversity.

8. Water quality:

– salinisation;

– stratification and subsequent deoxygenation of water column;

– reduction in habitat availability for aquatic fauna; and

– inhibition of aquatic macrophyte growth.

9. Flow regulation:

– altered flood frequency, magnitude, duration;

– changed flow seasonality; and

– diminished channel flushing.

10. Channel condition:

– bank erosion;

– stock access;

– riparian clearing; and

– desnagging.

11. Current values of the Glenelg River:

– riparian and instream flora present; and

– aquatic fauna community.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 18 12. Heritage river reach:

– high environmental value; and

– degraded riparian zone outside National Park.

3.2 Sand slugs Sand accumulation in stream channels is a major stream management issue in the Glenelg River catchment. Sheet, rill and gully erosion of granite portions of the catchment have filled the Glenelg and its tributaries with about 6,000,000 m3 of sand (Rutherfurd and Budahazy, 1996). Little sand is now coming from the catchment, so the major source of sand to the Glenelg River is the lower reaches of tributary streams. The tributaries introduce discrete slugs of sand to main channel that often partially dam the river, these slugs are commonly referred to as tributary junction plugs. As these sand slugs move downstream they attenuate, gradually giving way to a succession of small sluglettes. Rutherfurd and Budahazy (1996) estimate the sand slugs are moving through the stream network at a slow rate, with only tens of thousands of cubic metres being removed by bedload transport. The low transport rate is due, in part, to regulation of the river from Rocklands Reservoir.

The effect of the movement of sand into the Glenelg River and its tributaries is not clear. Rainfall- runoff modelling suggests that filling half of the channel cross-section with sand will have minimal impact on the size of flood peaks or their time-to-peak because of the decreased roughness associated with sand sheets. In addition, deposition on the floodplain has meant that in many reaches the rise in bed level has been matched by an increase in bank height.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 19 A complicating factor in managing sand in the Glenelg River is the form of channel adjustment that takes place once the sand is removed from a reach. Both Rutherfurd and Budahazy (1996) and Brizga et al. (2000) report examples of bed incision and consequent bank erosion following sand extraction from the channel. Bed incision of the main trunk can also lead to incision of the tributaries, particularly if those tributaries are graded to the elevation of the sand surface.

Brizga et al. found that in fact there were very few areas where sand comprised the only available habitat. While many pools may have partially filled with sand there is still a remnant sequence of pools and shallow areas usually with some residual LWD. However, the loss of deep holes in the river has removed sites of refuge for platypus during periods of low flow. Furthermore, artificially reduced flows during low flow periods may have implications for the movement of platypus between pools and foraging behaviour, thus restricting platypus to regions of poor water quality. Low flows and sediment deposition in the mid to upper Glenelg River have also been found to promote excessive growth of Typha spp. and Phragmites australis in the river channel (Mitchell et al. 1996). This consequently impedes flows and leads to further sediment deposition and further reduction in habitat complexity.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 20 from tributary inflows (Mitchell et al. 1996). Reduction in the magnitude of natural flows as a result of Rocklands Reservoir may also contribute to salinisation of downstream sites.

There is currently an flow allocation for the Glenelg River of 13,360 ML annually, although this is planned to increase with further stages of pipelining of the Wimmera Mallee Water system. The current releases differ from environmental flow recommendations as they are designed to sustain the ecosystem, rather than return all or part of the natural flow regime. However, these flows are not always delivered in their entirety. Deakin University is undertaking a biological monitoring program in the Glenelg River to determine if the environmental allocations have had a significant beneficial effect. Over the four seasons since 1994/95 when the monitoring began, there have effectively been two years when the allocation was delivered to approximately 20-25% of allocated flows and two years when it was 70-80% of recommended flows (B. Mitchell, pers. comm.). The reduction in flows delivered were due to periods of drought and subsequent water limitations.

The work of Anderson and Morrison (1989) and Mitchell et al. (1996) suggest that even if the environmental water was currently available, releasing large flushing flows down the river could have substantial short term detrimental effects but in the long term be beneficial. This short term detrimental effect would largely be due to the mobilisation of highly saline water or water with low dissolved oxygen levels from the existing deep pools. Sustained environmental flows would help to reduce salinity in shallow water and the upper water column, however, saline water in deep pools should not be managed using flushing (Mitchell et al. 1996). Mitchell et al. (1996) recommend sustaining environmental flows in the summer-autumn period to compensate for lost habitat with an additional provision for spring flows. The low level sustaining flows would also help manage the water quality within the surface water of the pools and the preliminary indications are that these flows are having a beneficial effect on the surface water quality (B. Mitchell pers. comm.) In the long term large flushing flows are important for managing the stream channel form and movement of sediment. These flows would also act as important disturbances to the biological community.

The salinity levels within the Glenelg River system may potentially affect a range of biota. It is considered for example, that fish are a good indicator of the effect of salinity on a river system

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 21 because they are mobile and their occurrence may reflect the health of a river reach (Ryan and Davies 1996). Some fish species found in the Glenelg River, for example the Common Galaxias (Galaxias maculatus), are relatively tolerant of salinity because of their migratory stages and may not be greatly affected by current salinity levels (Pollard 1971). Other species found in the Glenelg River, such as the River Blackfish (Gadopsis marmoratus), are relatively sensitive to saline conditions, particularly in juvenile life stages (Ryan and Davies 1996). Salinity levels found within the Glenelg River would also impact a range of invertebrate species, resulting in a reduction in diversity and abundance (Hart 1982).

Consequently the impacts of salinity may be two-fold, direct effects on biotic health and structural effects reducing useable habitat within the system.

3.4 Regulation Rocklands Reservoir has diverted water from the upper Glenelg River catchment to the Wimmera River system since 1953. The diversion has reduced the mean annual flow downstream of the dam from 113,000 ML/year naturally to 42,700 ML/year currently (data from this study). Alternate calculations have suggested that the mean annual natural flow downstream of Rocklands Reservoir, for the period 1990-99, were 103,000 ML and current annual flow was 19,000 ML (J. Martin pers comm.). Both of these figures clearly indicate that as a result of the diversion the natural flow regime of the Glenelg River has been substantially altered and is missing several critical flow elements. Firstly, the overall volumes of water are greatly reduced throughout the year and large flushing flows are absent. These changes exacerbate sand slug formation, saline pools and reduction in structural diversity. The mitigation of major floods also has implications for connectivity between the main channel of the Glenelg River and its floodplain.

The effect of regulation is obviously greatest immediately downstream of Rocklands Reservoir, although effects continue a significant distance downstream. The reduction in peak flows is highly significant all the way through to Casterton, downstream of the confluence with the Wannon the impact of peak flows is still apparent (e.g. at Dartmour) although is relatively reduced. As discussed these peaks flows are important for sand and sediment movement through the system. They also are considered to be key trigger flows for a number of biological events such as fish spawning and invertebrate recruitment. Consequently, reduction in timing, recurrence, duration and magnitude of peak flow events has a significant effect on both the biological and physical processes in the river.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 22 The Glenelg River system is considered self regulatory by Southern Rural Water. Southern Rural Water has not previously had a formal water restriction policy in place due to flow rapidly dropping to zero as water levels begin to fall during the summer months and water quality also declines. Ad hoc restrictions were imposed in the summer of 1998/99, during which river flow of 10 ML/day was used as a trigger to implement restrictions. Such restrictions were unnecessary due to the river rapidly dropping to zero flow once it was below 10 ML/day and the water becoming too saline for agricultural use. Therefore, the timing of bans coincided with conditions that were unsuitable for pumping due to lack of water and high salt levels. Similarly, restrictions were imposed on the Wannon last summer (1999/00) but due to the flow dropping very quickly by mid January such restrictions were once again unnecessary. Southern Rural Water also used 10 ML/day, an arbitrary figure, to impose restrictions on the Crawford River and the Grange burn Creek (J Donovan, pers. comm.).

Rocklands Reservoir also presents a barrier to the movement of migratory fish species and localised movement of non-migratory species. Although Mitchell et al. (1996) suggest that the spawning cycles of endemic native fish do not appear to be linked with flooding, altered flow regimes, in the Glenelg River, below Rocklands Reservoir, may have adversely impacted fish communities through eliminating other flow related cues. Flushes in late summer/early spring may be important for improving water quality after low flow periods. This, in turn, may affect the recruitment success of native fish species by influencing the survival of juvenile fish.

3.5 Channel condition A number of reports discuss the degraded condition of the Glenelg River (e.g. Rutherfurd and Budahazy; Brizga et al. 2000; Erskine ). Each of these have identified similar themes of degradation: q catchment sheet and gully erosion; q sand slugs; q sand extraction; q macrophyte loss; q localised bed and bank erosion; q riparian degradation (including unmanaged stock access); q desnagging; and q river regulation. Schreiber et al. (1998) also assessed the environmental aquatic habitat of the Glenelg River based on bed composition, proportion of pools and riffles, bank vegetation, degree of cover for fish and the extent of sedimentation or erosion. Their rating ranged from moderate to very poor.

The loss of aquatic macrophytes, salinisation, sedimentation, smothering and removal of snags and altered flow regimes have direct and indirect impacts on instream fauna (macroinvertebrates, fish, reptiles and amphibians, and other vertebrates). Aquatic vegetation and LWD are an important component of habitat complexity in deeper reaches of rivers (Walker et al. 1992) and are often correlated with macroinvertebrate species (O’Connor 1991 in Mitchell et al 1996) and fish species richness (Schlosser 1982).

Large woody debris plays a critical role in providing stable substrate and hydraulic diversity in sand- bed streams, and is arguably even more important in sand bed streams than other types of streams (Brizga et al. 2000). There has been significant desnagging within the Glenelg River system, particulalry in the reach in the Casterton region. Decreases in the diversity and abundance of aquatic macrophytes and the loss of LWD lead to a loss of food source, spawning sites and shelter for both aquatic macroinvertebrates and fish. However, the available data on macroinvertebrate populations in the river is equivocal. For example the heath of the Glenelg River was assessed as good to excellent in both pools and shallow habitats based on the macroinvertebrate communities present (OCE 1988).

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 23 Whereas as part of the National River Health Strategy the Glenelg River Catchment was described as highly degraded (Schreiber et al. 1998). (See Appendix D for more detail).

Riparian vegetation is particularly important to in-stream biota as it provides shading, food (terrestrial invertebrates) and shelter (leaf litter, woody debris). Riparian vegetation also influences water chemistry through filtering and buffering the in-stream environment from allocthanous sources of sediment, chemicals and nutrients. In the Glenelg River catchment, clearing of vegetation has resulted in sheet erosion that delivers sediment to the upper river. Moreover, removal of riparian vegetation in mid to lower reaches of the river has resulted in bank instability and subsequent bank slumping which has contributed to sedimentation and reduced capacity of the channel. Loss of riparian vegetation reduces shading for the stream channel and has a consequent affect on water temperature also. These processes reduce instream habitat complexity, an essential requirement for aquatic fauna in that it provides different microhabitats for shelter, spawning, food production etc.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 24 In addition to the listed flora and fauna of the Glenelg River system there are numerous other species of value to the region and community.

3.7 The heritage reach The lower section of the Glenelg River, from Nelson on the coast to Dartmoor, is designated a “Heritage River” under the Heritage Rivers ACT 1992 (DNRE 1997) and is listed as a Nationally Important Wetland by Environment Australia. The Heritage River corridor covers an area of approximately 3020 Ha and is about 50 m wide for most of its length. The lower section of the Heritage River flows through the Lower Glenelg National Park. The Heritage River corridor provides an important habitat link particularly between inland woodlands and the coast for species reliant on riparian habitats. This habitat corridor is well protected within the National park although public land water frontages are degraded at Nelson, Donovan’s and below Dartmoor (DNRE 1997).

Key management directions have been proposed for the lower sections of the Glenelg River that will maintain and enhance existing values (DNRE 1997). These include: q restore habitat links along the River to the coast; q improve environmental water values of the river, particularly the estuary, and develop trigger levels for opening of the river mouth; q undertake research and monitoring of significant fish species and environments, monitor sand and silt effects on the River including the sand slug upstream the heritage River corridor (DNRE 1997).

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 25 Flow related threats to the lower Glenelg River might include the encroachment of the upstream sand slug and the alteration of late summer/autumn and winter/spring flow events. Rutherfurd and Budhazy (1996) suggest that the sand slug may not reach the Heritage River for approximately 30-40 years. Nevertheless, the impacts of the sand slug are likely to be similar to those that have occurred in the mid to upper reaches of the Glenelg River (e.g. infilling of deep pools, smothering of substrates, etc) ultimately leading to decreased habitat complexity. With regards to the alteration of flows to the lower Glenelg River, this has not been quantified and hence it is difficult to determine the potential biological impacts.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 26 4. Environmental objectives

4.1 Preliminary umbrella objectives 1) Maintain/improve water quality in accordance with SEPP Waters of Victoria objectives (Government of Victoria, 1988). This section outlines the preliminary environmental 2) Achieve an assured and adequate quality of water resource and objectives that have been a balanced and fair distribution between human and environmental developed for the Glenelg uses (see Glenelg Regional Catchment Strategy: GRCLPB, 1997). River system. Two types of environmental objectives are 4.2 Preliminary specific objectives proposed: umbrella objectives (reflect state and 7) Provide an adequate environmental flow regime throughout the regional objectives) and year that includes: specific objectives (focus on q periods of no flows but without extending their frequency or environmental water duration;

q minimum environmental flows during low flow periods;

q appropriate flushing flows to manage salinity and nutrient levels; and

q flows of a sufficient magnitude to facilitate geomorphological processes.

8) Maintain and restore longitudinal connectivity by: q minimising changes in flow regime (from natural) due to regulation at Rocklands Reservoir; q improving flow over/through existing weirs; and q providing natural flood regime along entire stream length.

9) Maintain and improve (where possible) stream habitat condition by providing flows to enhance: q channel morphology; q appropriate water quality; q riparian vegetation; and q instream vegetation.

10) Maintain self-sustaining populations of endemic native fish with particular emphasis on threatened species.

11) Ensure that links to other strategies (e.g. Wagg, 1997) are fostered to promote the benefits of environmental flows.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 27 5. Outcomes

The previous sections have described the catchment, identified issues that are related to environmental water management and set out preliminary environmental management objectives. Following is a summary of further work that is required to assess the environmental flow requirements of the Glenelg River. The methodology that we have adopted is detailed in the state-wide methodology developed as part of the Stressed rivers project for the Wimmera, Avoca and Glenelg Rivers. The full state-wide methodology will not be repeated in detail here but in brief the key steps include: q field assessment of a number of field sites that typify relatively homogenous reaches; q hydraulic modelling to relate channel morphology to streamflow; q identification of critical flow components along with discussion of the ecological and geomorphological roles of these components; and q modelling flow components for different management scenarios to understand how the wetted area of the channel changes as critical flow components change under different management scenarios.

5.1 Assessment framework Information collected throughout the project, including agreement on critical flow components, will be used to finalise objectives. Recommendations will be then developed to meet each objective. The key basis for the recommendations will be an assessment of the differences between management scenarios within a number of study reaches by the technical panel.

5.1.1 Technical panel Fieldwork will be conducted at each of the sites by technical panel. The composition of the panel is not set at this stage but should include personnel experienced in: q hydrology; q aquatic ecology; and q geomorphology.

These disciplines will be combined across key project personnel as appropriate.

5.1.2 Study reaches In order to meet the environmental objectives of the Glenelg River, data for appropriate water resource management reaches are required. To this end the river has been divided into five distinct reaches. Within each reach, potential field sites have been identified where environmental value can be measured or gauged by technical panel. The reaches and sites have been selected on the basis of catchment issues and a number of practical criteria. Selection criteria include the proximity of sites to flow gauges, features of site that are typical of the wider reach (e.g. channel morphology and topography) and site access. Links with Deakin University studies in the catchment have been maintained by choosing common sites, where possible. Study reaches and field sites that meet these criteria are listed below. It should be noted that field sites may change with field inspection.

1) Headwaters to backwater of Rocklands Reservoir The upper reach is distinguished from the lower reaches on the basis of its relief, drainage density, adjacent landuse (predominantly National Park) and its lack of regulation.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 28 There was no field assessment undertaken in this reach as environmental flows were not a key issue in the reach.

2) Rocklands Reservoir to Chetwynd River This reach is very affected by regulation and salinisation. Two sites will be used to characterise the reach:

q Site 1 Downstream 5 mile outlet

q Site 2 Pine Hut Hole – upstream Gauge 238224

q Site 3 Upstream Harrow at Dick’s Place off Greens Lane

3) Chetwynd River to Wannon River The effects of regulation are diminished below the Chetwynd River confluence and the Chetwynd River remains one of the largest sources of sand to the Glenelg River. Two sites will be investigated to characterise this reach; q Site 4 Burkes Bridge – downstream Chetwynd River

q Site 5 Roseneath – upstream of bridge

q Site 6 Section Rd – downstream of bridge (Downstream Wando River)

4) Wannon River to tidal extent The Wannon River is the largest tributary of the Glenelg River, draining almost half the catchment. The Wannon River is also the watercourse most affected by abstractions for irrigation, other than the diversion at Rocklands Reservoir. Unregulated flows entering this reach distinguish it from its upstream counterparts. Hence this reach is of key importance in characterising the environmental flows of the Glenelg River. Two sites will be investigated by the technical panel:

q Site 7 Gauge 238202

q Site 8 Gauge 238206

5) Tidal extent to river mouth Heritage river reach. Although not particularly affected by abstractions, this reach is of high environmental value and consequently is of importance to this study. One site with adequate access will be chosen in the field. A detailed flow assessment at this site will not be undertaken, although a brief site inspection will be conducted.

Information collected at each site will include stream channel measurements and records of key features and issues as outlined in the state-wide methodology. This information will form the basis of a simple 1-D hydraulic model. The panel will also take photographs and video footage of each site. The aim of collecting this information is to allow the panel to understand and visualise how streamflow fluctuations affect instream habitat and ecosystem condition. A team member will undertake two subsequent visits to the field sites in order to provide an assessment of stream condition at different streamflows. This will involve the completion of a sub-set of the field sheets completed by the Technical Panel on the first trip and taking 180 degree photographs and videos of each site for latter analysis by the Technical Panel.

It should be noted that field sites may vary at the discretion of the technical panel. Sites might need to be altered due to flow-data availability, site access, channel modifications, etc.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 29 5.1.3 Use of existing data and information As referred to in this document, the existing data and literature on the Glenelg River are adequate to describe the environmental condition of the catchment. We propose to critically review the applicability of this information to the current assessment of environmental water requirements. In addition, Dr Brad Mitchell has offered to make available unpublished data sets on water quality, macroinvertebrates and fish habitat (e.g. mapping of snags) for analysis and evaluation as part of Phase 2 of this environmental flow study. The critical review and evaluation of existing data and information is a key step in developing recommendations as part of Phase 2.

5.2 Reporting Following finalisation of the state-wide methodology, fieldwork, consultation and further study, the technical panel will report its final recommendations for environmental objectives and for strategies to attain those objectives. Catchment issues that affect the flow regime of the Glenelg River will be addressed in the final report. Nevertheless, it is worth being clear here on the type and scope of those recommendations.

The final report will detail all strategies and works, directly related to environmental water allocations, required for the main trunk of the Glenelg River to attain the environmental objectives. It is expected that recommendations will include: q environmental flow recommendations for the Glenelg River, including a range of flow requirements at different times of the year and/or maximum extraction rates; q indication of the impact of the current water resource development within the catchment on instream habitat, specific species and broader ecological processes; q comment on the expected impact of additional water resource development for the agreed scenarios used as part of the hydraulic modelling; q appropriate monitoring program; and q suggestions for further work to fill knowledge gaps.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 30 6. References

Andrews, A.P. (1996). Family Bovichtidae. Congolli. Pages 198-199 in McDowall, R. M., ed. Freshwater fishes of south-eastern Australia. Reed Books, Chatswood. ANZECC (1992). Australian Water Quality Guidelines for Fresh and Marine Waters. A report for the National Water Quality Management Strategy. ANZECC, Canberra. ANZECC (2000). ANZECC List of Threatened Vertebrate Fauna. The Australian and New Zealand Environment Conservation Council, Canberra. ARMCANZ and ANZECC (1996). National Principles for the Provision of Water for Ecosystems. ARMCANZ and ANZECC, Sydney. Beumer, J.P. (1996). Family Anguillidae. Freshwater eels. Pages 39-43 in McDowall, R. M., ed. Freshwater fishes of south-eastern Australia. Reed Books, Chatswood. Bird, E.C.F. (1977). Sites of special scientific interest in the Victorian coastal region. A report on geological and geomorphological aspects prepared for the Town and Country Planning Board. Brizga, S.O., N.M. Craigie, P. Condina and Lawson and Treloar Pty Ltd (2000). Development of operational guidelines for sand management sites on the Glenelg River: Feasibility study. Final report to the Glenelg Hopkins Catchment Management Authority. Cameron, M. and Jekabsons, M. (1992). Salinity in the Glenelg and Wannon Rivers, Victoria. Department of Conservation and Natural Resources, Victoria, Chessman, B.C. (1995). Rapid assessment of rivers using macroinvertebrates: A procedure based on habitat-specific sampling, family level identification and a biotic index. Australian Journal of Ecology 20: 122-129. Davidson, N., Jeffery, G., and Wagg, C. (1994). The Environmental Condition of Streams in the Glenelg Basin. Department of Conservation and Natural Resources and National landcare Program, Victoria, DCNR (1993). Action Statement No. 42 Variegated (Ewen's Pygmy Perch) Nannoperca variegata . Department of Conservation and Natural Resources, East Melbourne. DWR (1989). Water Victoria: a Resource Handbook. Victorian Government Printing Office, Melbourne. Dixon, P.R., Wagg, C., and Amirtharajah, M. (1998). Aspects of Environmental Conditions in the Glenelg-Hopkins Region with Particular Reference to Salinity and Nutrients in Rivers, Wetlands and Remnant Vegetation. Department of Natural Resources and Environment, DNRE (1997). Heritage rivers and natural catchment areas. Draft management plans Volume 1 - Western Victoria. Department of Natural Resources and Environment, East Melbourne. DNRE (1997a). Victoria's Environmental Flow Program. Department of Natural Resources and Environment. DNRE (2000a). Atlas of Victorian Wildlife. Arthur Rylah Institute - Department of Natural Resources and Environment, Heidelberg. DNRE (2000b). Threatened vertebrate fauna in Victoria - 2000. Department of Natural Resources and Environment, East Melbourne. DNRE (2000c). Victorian Aquatic Fauna Database. Arthur Rylah Institute - Department of Natural Resources and Environment, Heidelberg. Doeg, T. . a. K., J.D. (1994). Effects of draining and desilting a small weir on downstream fish and macroinvertebrates. Regulated Rivers: Research and Management 9: 263-277. EPA (1999). The health of streams in the Glenelg catchment. River Health Bulletin. Environment Protection Authority, Victoria. Erskine, W.D. (1994). River response to accelerated soil erosion in the Glenelg River catchment. Australian Journal of Soil and Water Conservation 7: 39-47. Godoy, W. (1996). The Effects of Rocklands Reservoir on the Glenelg River. Department of Natural Resources and Environment - Water Bureau, July 1996.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 31 GRCLPB (1997). Glenelg Regional Catchment Strategy. Glenelg Regional Catchment and Land Protection Board, May 1997. Gullan, P.K., Cheal, D.C. and Walsh, N.G. (1990). Rare or threatened plants in Victoria. Department of Conservation and Environment, East Melbourne. Harris, J. H. a. R., S.J. (1996). Family Percichthyidae. Australian freshwater cods and basses. Pages 150-163 in McDowall, R. M., ed. Freshwater fishes of south-eastern Australia. Reed Books, Chatswood. HArt, B.T. (1982). Water quality: formulation of criteria. In: O'Loughlin, E.M. and Cullen, P. (Eds) Predictions in Water quality. Australian Academy of Science, Canberra, pp 11-26. Humphries, P. (1986). Observations on the ecology of Galaxiella pusilla (Mack) (Salmoniformes: Galaxiidae) in Diamond Creek, Victoria. Proceedings of the Royal Society of Victoria 98: 133- 137. Ingeme, Y. (1996). Glenelg River Catchment Environmental Flows Technical Report - Draft Report. Department of Natural Resources and Environment, July 1996. Koehn, J. D. a. O. C., W.G. (1990). Biological information for the management of native freshwater fish in Victoria . Government Printer, Melbourne. Koster, W.M. (1997). A study of the interactions between the dwarf galaxias, southern pigmy perch and eastern gambusia. Pages 88. School of Ecology and Environment. Deakin University, Melbourne. Kuiter, R.H., Humphries, P.A. and Arthington, A.H. (1996). Family Nannopercidae. Pygmy perches. Pages 168-175 in McDowall, R. M., ed. Freshwater fishes of south-eastern Australia . Reed Books, Chatswood. Larson, H. K. a. H., D.F. (1996). Family Gobiidae, subfamilies Eleotrinidae and Butinae. Gudgeons. Pages 200-219 in McDowall, R. M., ed. Freshwater fishes of south-eastern Australia. Reed Books, Chatswood. LCC (1991). Glenelg River - Victorian heritage river. Rivers and streams special investigation - final recommendations. Report extract. Land Conservation Council, Victoria. McDowall, R.M. (1996a). Family Retropinnidae. Southern smelts. Pages 92-95 in McDowall, R. M., ed. Freshwater fishes of south-eastern Australia. Reed Books, Chatswood. McDowall, R.M. a. F., W. (1996b). Family Galaxiidae. Galaxiids. Pages 52-77 in McDowall, R. M., ed. Freshwater fishes of south-eastern Australia. Reed Books, Chatswood. McDowall, R. M. a. F., W. (1996c). Family Prototroctidae. Southern graylings. Pages 96-98 in McDowall, R. M., ed. Freshwater fishes of south-eastern Australia . Reed Books, Chatswood. McGuckin, J.T., Anderson, J.R., and Gasior, R.J. (1991). Salt Affected Rivers in Victoria. Arthur Rylah Institute for Environmental Research, July 1991. Mitchell, B., Rutherfurd, I., Constable, A., Stagnitti, F., and Merrick, C. (1996). An Ecological and Environmental Flow Study of the Glenelg River from Casterton to Rocklands Reservoir. Aquatic Resource Utilisation and Management Research Group, Deakin University, Warrnambool. August 1996. Mitchell, B., Rutherfurd, I., Constable, A., Stagnitti, F., and Merrick, C. (1996). An Ecological and Environmental Flow Study of the Glenelg River from Casterton to Rocklands Reservoir. Aquatic Resource Utilisation and Management Research Group, Deakin University, Warrnambool. Mitchell, P. (1990). The Environmental Condition of Victorian Streams. Department of Water Resources, Victoria. OCE (1988). State of the environment report 1988. Victoria's inland waters. Office of the Commissioner for the Environment, Victoria. O'Connor, W.G. a. K., J.D. (1998). Spawning of the broad-finned galaxias, Galaxias brevipinnis Gunther (Pisces: Galaxiidae) in coastal streams of southeastern Australia. Ecology of Freshwater Fish 7: 95-100.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 32 Pollard, D.A. (1971). The biology of a landlocked form of the normally catadromous salmoniform fish Galaxias maculatus (Jenyns). I. life cycle and origin. Australian Journal of Marine and Freshwater Research 22: 91-123. Rutherfurd, I.D. and Budahazy, M. (1996). A Sand Management Strategy for the Glenelg River and its Tributaries, Western Victoria. Report to the Department of Natural Resources and Environment, Victoria and Southern Rural Water. Cooperative Research Centre for Catchment Hydrology, Report 96/9, Melbourne. Melbourne. December, 1996. Ryan, T. and Davies, P. (1996). Environmental effects of salinity and nutrients from salt disposal: approaches to the development of management criteria. Flora and Fauna Technical Report 137. Department of Natural Resources and Environment. SAC (1991a). Final recommendation on a nomination for listing. Edelia obscura (Klunzinger, 1972) - Yarra Pygmy Perch. Nomination No. 125. Flora and Fauna Guarantee - Scientific Advisory Committee, Victoria. SAC (1991b). Final recommendation on a nomination for listing. Galaxiella pusilla (Mack, 1936) - Dwarf Galaxias. Nomination No. 141. Flora and Fauna Guarantee - Scientific Advisory Committee, Victoria. SAC (1991c). Final recommendation on a nomination for listing. Prototroctes maraena (Gunther, 1864) - Australian Grayling. Nomination No. 3. Flora and Fauna Guarantee - Scientific Advisory Committee, Victoria. SKM (2001). Glenelg River Natural Flow Estimation. Report to the Department of Natural Resources and Environment. Sinclair Knight Merz. Schlosser, I.J. (1982). Fish community structure and function along two habitat gradients in a headwater stream. Ecological Monographs 52: 395-414. Schreiber, E.S.G., Wagg, C., Metzeling, L., and Perriss, S. (1998). Assessing stream health in the Glenelg catchment - using macroinvertebrates. Department of natural Resources and Environment and Environment Protection Authority, Sherwood, J., Magilton, C. and Rouse, A. (1998a). The Glenelg River: Nutrient and Estuarine Hydrodynamics. Deakin University, Warrnambool. July 1998. Sherwood, J., Magilton, C. and Rouse, A. (1998b). The Glenelg River: Nutrients and Estuarine Hydrodynamics. Department of Natural Resources and Environment, Hamilton. July. VWQMN (1999). Victorian Water Quality Monitoring Network Database, AWT Victoria. Wagg, C. (1997). A Summary of the Water Quality in the Glenelg Catchment. Department of Natural Resources and Environment, Walker, K.F., Thoms, M.C., and Sheldon, F. (1992). Effect of weirs on the littoral environment of the River Murray, South Australia. Pages 270-293 in Boon, P. J., Calow, P. A., and Petts, G. E., eds. River Conservation and Management. Wiley, Chichester. Zeidler, W. and Adams, M. (1990). Revision of the Australian crustacean genus of freshwater crayfish Gramastacus Riek (Decapoda: Parastacidae). Invertebrate Taxonomy 3: 913-924.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 33 Appendix A Hydrology

Hydrology is an integral component to the development of environmental flows. It is important to understand where and when water is being diverted as well as the volumes of diversion so that it can be identified what source, if any, may supply water back to the environment.

This chapter outlines the demands that are placed on the system by water extraction as well as the operation of the Glenelg River system downstream from Rocklands Reservoir. The patterns of streamflows are also compared between natural flow (no extraction) and the current level of demand at six geographically distinct locations within the project area. A resource allocation model (REALM) was constructed to quantify flows under natural and contemporary conditions.

Natural flows were calculated by adding rural and urban water demands to gauged flow data. All catchment storages were accounted for during the process. Natural flows generated in this manner do not reflect potential changes to flows as a result of landuse changes. Only those licensed private diverters on the Wannon River were considered in the generation of natural flows. Private diversions from the Glenelg River and its other tributaries are small relative to its flows and as such were assumed to be negligible. Current conditions were assumed to be equal to the 1993/94 level of development and were generated using REALM (SKM 2001b).

A.1 Streamflows Rainfall varies seasonally and spatially within the catchment. Although winter months are wetter throughout the catchment, there is a gradual decline in mean annual rainfall from the coast near Nelson (approximately 750 mm) to the centre of the catchment (approximately 550 mm). In the northeast of the catchment, in the vicinity of the Grampians, annual rainfall increases with elevation to more than 900 mm on the Victoria Range. Rainfall is relatively reliable along the coast and in the higher parts of the Grampians (Department of Water Resources Victoria 1989).

Reflecting rainfall distribution, flows are strongly seasonal with 70% of average annual flow in the Glenelg River above the Wannon River junction occurring in the three months August to October. At Dartmoor (Station No. 238 206), the residual mean annual flow of the Glenelg River is 639,000 ML. Although only 1.5 % of that total occurs in the months January to March, there are reliable base flows rarely falling below 30 ML per day during this period (Department of Water Resources Victoria 1989).

The Glenelg River, under natural conditions, commonly dried up at Balmoral over the three months February to April, sometimes for months longer. Flows at Balmoral are now highly regulated by Rocklands Reservoir. Rocklands has a storage capacity about three times its average annual inflow. Since construction Rocklands Reservoir has spilled 14 times, approximately every four years on average. However, current releases from Rocklands Reservoir do not appear to exert an influence below Casterton due to the size of these releases 20-25 ML/day (Mitchell et al. 1996).

Under low flow conditions transit times for releases from Rocklands are approximately 7 days to Balmoral, 14 days to Fulham Bridge and 21 days to Harrow. According to Mitchell (1996) a continuous 20-25 ML/day release from Rocklands Reservoir delivers 10 ML/day at Fulham Bridge and 2 ML/day at Harrow.

Streamflows within the Glenelg River exhibit the greatest alteration due to development at Rocklands Reservoir, as exhibited by the variation between pre-regulation flows (natural flows) and flows under

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 34 the current level of development (current flows). Flows are least affected by development upstream of Rocklands Reservoir.

Streamflows (frequency, duration and magnitude) upstream of Rocklands Reservoir are similar under natural and current conditions for the majority of the year (April to November inclusive) (Figure A.5). The most significant difference in current and natural flows is most distinct during January and February. During February, 10 ML/month is exceeded 95% of the time under natural conditions, while under current conditions this flow is only exceeded 73% of the time. Under current conditions, there is no flow at this site for 20% of the time during February.

Streamflows are significantly altered from natural immediately downstream of Rocklands Reservoir. At this site under natural conditions, median flows peak during August at 23 400 ML/month (Figure A.4). Lowest flows occur during the summer months, particularly February. The current flow pattern is the inverse of that that occurs under natural conditions reflecting discharge from the reservoir (Figure A.7). Current flows are less than natural flows during all months of the year. Zero flows occur during the months May to November, inclusive. Peak flows at this site occur during December to February, inclusive, under current conditions. During June and July zero flow prevails 100% of the time under current conditions (Figure A.5). Between August and October, flow exceeds 0 ML/month for less than 18% of the time under current conditions, while under natural conditions, flow exceeded 600 ML/month 100% of the time.

At Fulham Bridge, about 20 km downstream of Rocklands Reservoir, the current level of development results in much lower flows, although the pattern of flows is similar (Figure A.5). Flows peak during August under both current and natural conditions (approximately 9,000 and 31,000 ML/month respectively). The breadth of the peak is however much broader under natural conditions. Streamflow begins to peak during April and declines during December under natural conditions, while under current conditions, streamflow begins to peak during June and decline during November. The summer low flows are considerably lower under current conditions than would naturally occur.

Further downstream, at Casterton the pattern of streamflows is similar to that at Fulham Bridge but with considerably higher flows under both natural and current conditions. The peak median flows under both current and natural conditions occur during August, however flow under natural conditions is approximately 65 000 ML/month while under current conditions flow is approximately 44 000 ML/month (Figure A.4). The summer flows that occur under natural conditions are also higher than those that occur under current conditions.

The Wannon River at the Glenelg River confluence has similar streamflows under both natural and current conditions. Natural flows exhibit a peak of flow during August of 45 600 ML/month while that under current conditions peaks during 44 400 ML/month (Figure A.4). The similarity in flows may be due to the number of sleeper licences on this reach. Only 61% of the total licensed entitlements are currently active.

Natural and current streamflows at Dartmoor are also similar with a slight reduction in streamflows under the current conditions. Natural flows at Dartmoor exceed current flows for all months of the year (Figure A.5). The peak in streamflow at this site occurs during August at this site under both natural (155 000 ML/month) and current conditions (132 500 ML/month). The breadth of this peak is also similar, beginning during May and declining up until December. Similar to the Wannon River site, low flows under natural conditions are higher.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 35 n Table 6-1: Licensed private diversions from the Glenelg River system (figures are ML/day, those in parenthesise indicate number of licences). Stream Irrigation Dairy Winter Fill Total 66 2.2 - 68.2 Glenelg River (2) (1) (3) - 2.2 - 2.2 Glenelg River Trib (1) (1) - 2.2 - 2.2 Corea Ck (1) (1) 50 - - 50 Crawford River (1) (1) 587.8 4.4 232 824.2 Wannon River1 (8) (2) (4) (14) 703.8 11 232 946.8 Total (11) (5) (4) (20) 1Data for the main channel of the Wannon River and its tributaries are pooled under the Wannon River. A.2 Licensed water use A large proportion of the water used within the Glenelg River Basin is obtained from groundwater. This volume is equal to 2/3 of the total water used (Department of Water Resources Victoria 1989).

Information on the licensed entitlement within the Glenelg River system is presented, which is distinct from the total volume that is actually extracted each year due to a number of factors including the availability of flow and water quality.

The total licensed volume for water extraction from the main channel of the Glenelg River is 68.2 ML/year which is a very small proportion of the total licensed water entitlement in the Glenelg River system. An additional 878.6 ML/year is licensed for extraction from the remainder of the Glenelg River System. The majority of extractions in the system are through irrigation licences held on the Wannon River and its tributaries. A total annual entitlement of 824.2 ML is held on the Wannon River, of which 587.8 ML is licensed for extraction through 8 licences (Table 6-1).

Licences to divert water from within the Glenelg River system have been granted for the purposes of irrigation, dairy and winter dam-fill. Licences for irrigation in the Glenelg River system are generally used sometime between September and February, although the specific timing of such use is dependent on the crops being irrigated. The dairy licences are used throughout the year for the purposes of washing the dairy and watering stock. The winter fill licences are used to fill both onstream and offstream storages during winter.

All licences on the Glenelg River extract upstream of the Wannon River confluence (J Donovan, pers. comm.). Of the 68.2 ML/year available for extraction from the Glenelg River proper, 66 ML/year is available for extraction through two irrigation licences. The remaining 2.2 ML/year is a dairy licence. Two additional dairy licences are held on tributaries of the Glenelg River, other than the Wannon River. The largest volume licence that is not held on the Wannon River or one of its tributaries is a licence for 50 ML/year for an instream storage on Crawford River, which enters the Glenelg River near Dartmoor. The largest winter fill licence for the whole catchment is held on Muddy Creek, a tributary of the Wannon River, for 150 ML/year.

The Glenelg River system is self regulatory. Southern Rural Water has not previously had a formal water restriction policy in place due to flow rapidly dropping to zero as water levels begin to fall during the summer months and water quality also declines. Ad hoc restrictions were imposed last summer (1998/99), during which river flow of 10 ML/day was used as a trigger to implement restrictions. Such restrictions were unnecessary due to the river rapidly dropping to zero flow once it was below 10 ML/day and the water becoming too saline. Therefore, bans were being imposed when

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 36 conditions were unsuitable for pumping due to lack of water and high salt levels. Similarly, restrictions were imposed on the Wannon last summer (1999/00) but due to the flow dropping very quickly over a short period of time, and then to no flow by mid January such restrictions were once again unnecessary. Southern Rural Water also used 10 ML/day, an arbitrary figure, to impose restrictions on the Crawford River and the Grange burn Creek.

A.3 System operation Three major water storages exist within the Glenelg River Basin. These are Konong Wootong Reservoir, Moora Moora Reservoir and Rocklands Reservoir. Konong Wootong is a small reservoir constructed on Den Hills Creek, a tributary of the Wannon River, to supply the townships of Casterton and Coleraine. The capacity of this storage is 1920 ML and diverts approximately 852 ML/year out of the system (Ingeme 1996). Moora Moora Reservoir is a small, offstream storage with a capacity of only 6,300 ML located in the upper reaches of the Glenelg River (Department of Water Resources Victoria 1989). This storage does not remain full over the summer period as much of the flow is used to supply part of the summer domestic and stock demand to the Wimmera River system.

Rocklands Reservoir is the largest storage in the Wimmera Mallee Water Supply System. It was completed in 1953 and has a total capacity of 348, 000 ML. The primary purpose of this storage is to provide domestic and stock supply to the Wimmera Basin (Godoy 1996). Approximately 85% of the water from the upper Glenelg River is diverted out of the system from Rocklands Reservoir. This amounts to 76 000ML/year of diversion out of the basin into the Wimmera-Mallee Domestic and Stock Supply System (Cameron and Jekabsons 1992). Water is diverted via the Moora Channel to Distribution Heads in the Wimmera River catchment.

Rocklands Reservoir has a significant impact on the seasonal flow pattern downstream of the reservoir between the dam wall and the confluence of the Chetwynd River. The impact decreases with distance from the storage. Downstream of Chetwynd River flows are generally continuous due to natural inflow from the catchment adding to the river flows, this section of river was observed to cease to flow in December 2000 (M. Tranter pers. comm.). The Glenelg River dries upstream of the confluence each year (Godoy 1996).

A compensation flow from Rocklands Reservoir down the Glenelg River is fixed at 3300 ML/year. This was previously a sliding scale between 2500 ML and 3700 ML/year, but at the request of the Glenelg Hopkins CMA, a new formula has been developed being the average of the historic releases, i.e. 3300 ML/year (R Leeson, pers. comm.). Wimmera Mallee Water is required to maintain a reserve volume in Rocklands to guarantee this compensation flow. This compensation flow is subject to restrictions during times of drought. The compensation flows aimed to maintain a target flow of 10-11 ML/day at Fulham Bridge, and consequently 1-2 ML/day at Harrow at all times.

Commencement of compensation flows is timed to take advantage of the wet river channel and thus prevent the flow from ceasing altogether (Godoy 1996). Releases to the river are based on the flow at Fulham's Bridge (238224). Compensation flows are timed to maintain a minimum flow of 15 ML/day at Fulham’s Bridge (R Leeson, pers. comm.). The compensation flows are generally released between mid November to late April and are in the order of 15-25 ML/day, weather dependent. There is, however, leakage from the Rocklands-Toolondo channel back into the river, as such the releases are reduced to account for this gain (Godoy 1996).

The Rocklands Outlet channel passes from Rocklands Reservoir over the Great Dividing Range to Toolondo Reservoir in the Wimmera Catchment. Water is also lost from the Glenelg River due to evaporation at Fraser's Swamp and water being held up by the sand slugs that are present in the stream. To compensate for the losses along the river to Fulham's Bridge, Wimmera Mallee Water

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 37 release water from the 5 and 12 Mile channel outfalls i.e. outfalls on the Rocklands Outlet channel located 5 or 12 channel miles from the reservoir. These outfalls have been used to: q reduce the time taken for flows to reach the “lower” part of the River if flows at Fulham bridge have suddenly dropped; q avoid capacity problems in the “upper” reaches of the river during times of high environmental flow releases; and q avoid the high losses that seem to occur in the Rocklands – Fulham Bridge reach (R Leeson, pers. comm.).

Wimmera Mallee Water has found that flows in the order of 50 ML/d are larger than the river channel’s capacity in some areas upstream of Balmoral. In particular, on Trevor Wood’s property some adjoining minor flood lines also carry water during this period, which significantly limits access to the property.

A.4 Summary The current level of development along the Glenelg River has resulted in streamflows frequently being considerably lower than that which would have occurred under natural conditions. The greatest impact along the Glenelg River is caused by the presence and management of Rocklands Reservoir in the upper reaches of the river. Rocklands Reservoir has drastically reduced the frequency of large flows that under natural conditions occurred during late winter and into September. Compensation flows are released from Rocklands Reservoir between November and April, and are approximately of 15-25 ML/day, weather dependent. During the remainder of the year, flows immediately downstream of the storage are zero. To account for losses from the Glenelg River between Rocklands Reservoir and Fulham Bridge, water is released into the Glenelg River from the 5 and 12 Mile channel outfalls. This is done to ensure the flows achieve the desired target at Fulham Bridge. Although, this is generally only done when transfers are being made to Toolondo Reservoir.

Progressively downstream, flow increases due to runoff, groundwater and flow from tributaries. Licensed demand on the Wannon River is having little effect on the streamflows of this river near the confluence of the Glenelg River.

The majority of private diversion licences to extract water from the Glenelg River catchment are held on the Wannon River, of which the licences are primarily not used (sleeper licences). Water use along the Glenelg River has its greatest impact on peak flow periods, reducing the magnitude of such flows. A formal restriction policy is not developed for the Glenelg River but restrictions are generally imposed during low flow periods as during such times flows rapidly drop to zero and prevailing water quality renders the water unsuitable for use.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 38 A.5 Flow plots

Glenelg River upstream of Rocklands - Natural Flow Glenelg River upstream of Rocklands - Current Flow

40000 40000

35000 35000

30000 30000

25000 25000

80th Percentile 80th Percentile 20000 Median 20000 Median 20th Percentile 20th Percentile

15000 15000 Monthly Flow (ML/month) Monthly Flow (ML/month)

10000 10000

5000 5000

0 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Glenelg River at Rocklands Outlet-Natural Flow Glenelg River at Rocklands Outlet-Current Flow

40000 40000

35000 35000

30000 30000

25000 25000

80th Percentile 80th Percentile 20000 Median 20000 Median 20th Percentile 20th Percentile

15000 15000 Monthly Flow (ML/month) Monthly Flow (ML/month)

10000 10000

5000 5000

0 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 39 Glenelg River at Fulhams Bridge-Natural Flow Glenelg River at Fulhams Bridge-Current Flow

60000 60000

50000 50000

40000 40000

80th Percentile 80th Percentile 30000 Median 30000 Median 20th Percentile 20th Percentile

Monthly Flow (ML/month) 20000 Monthly Flow (ML/month) 20000

10000 10000

0 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Glenelg River at Casterton- Natural Flow Glenelg River at Casterton-Current Flow

120000 120000

110000 110000

100000 100000

90000 90000

80000 80000

70000 70000 80th Percentile 80th Percentile 60000 Median 60000 Median 20th Percentile 20th Percentile 50000 50000

Monthly Flow (ML/month) 40000 Monthly Flow (ML/month) 40000

30000 30000

20000 20000

10000 10000

0 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 40 Wannon at Glenelg River - Natural Flow Wannon at Glenelg River - Current Flow

100000 100000

90000 90000

80000 80000

70000 70000

60000 60000

80th Percentile 80th Percentile 50000 Median 50000 Median 20th Percentile 20th Percentile

40000 40000 Monthly Flow (ML/month) Monthly Flow (ML/month) 30000 30000

20000 20000

10000 10000

0 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Glenelg River at Dartmoor - Natural Flow Glenelg River at Dartmoor - Current Flow

260000 260000

240000 240000

220000 220000

200000 200000

180000 180000

160000 160000

140000 20th Percentile 140000 20th Percentile Median Median 120000 80th Percentile 120000 80th Percentile

100000 100000 Monthly Flow (ML/month) Monthly Flow (ML/month) 80000 80000

60000 60000

40000 40000

20000 20000

0 0 Jan Feb Mar Apr May June July Aug Sep Oct Nov Dec Jan Feb Mar Apr May June July Aug Sep Oct Nov Dec

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 41 A.6 Flow duration curves

Flow duration curve for Glenelg River upstream of Rocklands Flow duration curve for Glenelg River upstream of Rocklands -JANUARY- -FEBRUARY- 100000 100000

Est. natural flow Est. natural flow Current Conditions Current Conditions 10000 10000

1000 1000

100 100 Monthly Flow (ML/month) Monthly Flow (ML/month)

10 10

1 1 3 3 15 26 38 50 62 74 85 97 15 26 38 50 62 74 85 97 Proportion of time exceeded (%) Proportion of time exceeded (%)

Flow duration curve for Glenelg River upstream of Rocklands Flow duration curve for Glenelg River upstream of Rocklands -MARCH- -APRIL- 100000 100000

Est. natural flow Est. natural flow Current Conditions Current Conditions 10000 10000

1000 1000

100 100 Monthly Flow (ML/month) Monthly Flow (ML/month)

10 10

1 1 3 3 15 26 38 50 62 74 85 97 15 26 38 50 62 74 85 97 Proportion of time exceeded (%) Proportion of time exceeded (%)

Flow duration curve for Glenelg River upstream of Rocklands Flow duration curve for Glenelg River upstream of Rocklands -MAY- -JUNE- 100000 100000

Est. natural flow Est. natural flow Current Conditions Current Conditions 10000 10000

1000 1000

100 100 Monthly Flow (ML/month) Monthly Flow (ML/month)

10 10

1 1 3 3 15 26 38 50 62 74 85 97 15 26 38 50 62 74 85 97 Proportion of time exceeded (%) Proportion of time exceeded (%)

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 42 Flow duration curve for Glenelg River upstream of Rocklands Flow duration curve for Glenelg River upstream of Rocklands -JULY- -AUGUST- 100000 100000

Est. natural flow Est. natural flow Current Conditions Current Conditions 10000 10000

1000 1000

100 100 Monthly Flow (ML/month) Monthly Flow (ML/month)

10 10

1 1 3 3 15 26 38 50 62 74 85 97 15 26 38 50 62 74 85 97 Proportion of time exceeded (%) Proportion of time exceeded (%)

Flow duration curve for Glenelg River upstream of Rocklands Flow duration curve for Glenelg River upstream of Rocklands -SEPTEMBER- -OCTOBER- 100000 100000

Est. natural flow Est. natural flow Current Conditions Current Conditions 10000 10000

1000 1000

100 100 Monthly Flow (ML/month) Monthly Flow (ML/month)

10 10

1 1 3 3 15 26 38 50 62 74 85 97 15 26 38 50 62 74 85 97 Proportion of time exceeded (%) Proportion of time exceeded (%)

Flow duration curve for Glenelg River upstream of Rocklands Flow duration curve for Glenelg River upstream of Rocklands -NOVEMBER- -DECEMBER- 100000 100000

Est. natural flow Est. natural flow Current Conditions Current Conditions 10000 10000

1000 1000

100 100 Monthly Flow (ML/month) Monthly Flow (ML/month)

10 10

1 1 3 3 15 26 38 50 62 74 85 97 15 26 38 50 62 74 85 97 Proportion of time exceeded (%) Proportion of time exceeded (%)

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 43 Flow duration curve for Glenelg River at Rocklands Outlet Flow duration curve for Glenelg River at Rocklands Outlet -JANUARY- -FEBRUARY- 100000 100000

Est. natural flow Est. natural flow Current Conditions Current Conditions 10000 10000

1000 1000

100 100 Monthly Flow (ML/month) Monthly Flow (ML/month)

10 10

1 1 3 3 15 26 38 50 62 74 85 97 15 26 38 50 62 74 85 97 Proportion of time exceeded (%) Proportion of time exceeded (%)

Flow duration curve for Glenelg River at Rocklands Outlet Flow duration curve for Glenelg River at Rocklands Outlet -MARCH- -APRIL- 100000 100000

Est. natural flow Est. natural flow Current Conditions Current Conditions 10000 10000

1000 1000

100 100 Monthly Flow (ML/month) Monthly Flow (ML/month)

10 10

1 1 3 3 15 26 38 50 62 74 85 97 15 26 38 50 62 74 85 97 Proportion of time exceeded (%) Proportion of time exceeded (%)

Flow duration curve for Glenelg River at Rocklands Outlet Flow duration curve for Glenelg River at Rocklands Outlet -MAY- -JUNE- 100000 100000

Est. natural flow Est. natural flow Current Conditions Current Conditions 10000 10000

1000 1000

100 100 Monthly Flow (ML/month) Monthly Flow (ML/month)

10 10

1 1 3 3 15 26 38 50 62 74 85 97 15 26 38 50 62 74 85 97 Proportion of time exceeded (%) Proportion of time exceeded (%)

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 44 Flow duration curve for Glenelg River at Rocklands Outlet Flow duration curve for Glenelg River at Rocklands Outlet -JULY- -AUGUST- 100000 100000

Est. natural flow Est. natural flow Current Conditions Current Conditions 10000 10000

1000 1000

100 100 Monthly Flow (ML/month) Monthly Flow (ML/month)

10 10

1 1 3 3 15 26 38 50 62 74 85 97 15 26 38 50 62 74 85 97 Proportion of time exceeded (%) Proportion of time exceeded (%)

Flow duration curve for Glenelg River at Rocklands Outlet Flow duration curve for Glenelg River at Rocklands Outlet -SEPTEMBER- -OCTOBER- 100000 100000

Est. natural flow Est. natural flow Current Conditions Current Conditions 10000 10000

1000 1000

100 100 Monthly Flow (ML/month) Monthly Flow (ML/month)

10 10

1 1 3 3 15 26 38 50 62 74 85 97 15 26 38 50 62 74 85 97 Proportion of time exceeded (%) Proportion of time exceeded (%)

Flow duration curve for Glenelg River at Rocklands Outlet Flow duration curve for Glenelg River at Rocklands Outlet -NOVEMBER- -DECEMBER- 100000 100000

Est. natural flow Est. natural flow Current Conditions Current Conditions 10000 10000

1000 1000

100 100 Monthly Flow (ML/month) Monthly Flow (ML/month)

10 10

1 1 3 3 15 26 38 50 62 74 85 97 15 26 38 50 62 74 85 97 Proportion of time exceeded (%) Proportion of time exceeded (%)

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 45 Flow duration curve for Glenelg River at Fulhams Bridge Flow duration curve for Glenelg River at Fulhams Bridge -JANUARY- -FEBRUARY- 100000 100000

Est. natural flow Est. natural flow Current Conditions Current Conditions 10000 10000

1000 1000

100 100 Monthly Flow (ML/month) Monthly Flow (ML/month)

10 10

1 1 3 3 15 26 38 50 62 74 85 97 15 26 38 50 62 74 85 97 Proportion of time exceeded (%) Proportion of time exceeded (%)

Flow duration curve for Glenelg River at Fulhams Bridge Flow duration curve for Glenelg River at Fulhams Bridge -MARCH- -APRIL- 100000 100000

Est. natural flow Est. natural flow Current Conditions Current Conditions 10000 10000

1000 1000

100 100 Monthly Flow (ML/month) Monthly Flow (ML/month)

10 10

1 1 3 3 15 26 38 50 62 74 85 97 15 26 38 50 62 74 85 97 Proportion of time exceeded (%) Proportion of time exceeded (%)

Flow duration curve for Glenelg River at Fulhams Bridge Flow duration curve for Glenelg River at Fulhams Bridge -MAY- -JUNE- 100000 100000

Est. natural flow Est. natural flow Current Conditions Current Conditions 10000 10000

1000 1000

100 100 Monthly Flow (ML/month) Monthly Flow (ML/month)

10 10

1 1 3 3 15 26 38 50 62 74 85 97 15 26 38 50 62 74 85 97 Proportion of time exceeded (%) Proportion of time exceeded (%)

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 46 Flow duration curve for Glenelg River at Fulhams Bridge Flow duration curve for Glenelg River at Fulhams Bridge -JULY- -AUGUST- 100000 1000000

Est. natural flow Est. natural flow Current Conditions Current Conditions 100000 10000

10000

1000

100

Monthly Flow (ML/month) Monthly Flow (ML/month) 100

10 10

1 1 3 3 15 26 38 50 62 74 85 97 15 26 38 50 62 74 85 97 Proportion of time exceeded (%) Proportion of time exceeded (%)

Flow duration curve for Glenelg River at Fulhams Bridge Flow duration curve for Glenelg River at Fulhams Bridge -SEPTEMBER- -OCTOBER- 100000 1000000

Est. natural flow Est. natural flow Current Conditions Current Conditions 100000 10000

10000

1000

100

Monthly Flow (ML/month) Monthly Flow (ML/month) 100

10 10

1 1 3 3 15 26 38 50 62 74 85 97 15 26 38 50 62 74 85 97 Proportion of time exceeded (%) Proportion of time exceeded (%)

Flow duration curve for Glenelg River at Fulhams Bridge Flow duration curve for Glenelg River at Fulhams Bridge -NOVEMBER- -DECEMBER- 100000 100000

Est. natural flow Est. natural flow Current Conditions Current Conditions 10000 10000

1000 1000

100 100 Monthly Flow (ML/month) Monthly Flow (ML/month)

10 10

1 1 3 3 15 26 38 50 62 74 85 97 15 26 38 50 62 74 85 97 Proportion of time exceeded (%) Proportion of time exceeded (%)

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 47 Flow duration curve for Glenelg River at Casterton Flow duration curve for Glenelg River at Casterton -JANUARY- -FEBRUARY- 100000 100000

Est. natural flow Est. natural flow Current Conditions Current Conditions 10000 10000

1000 1000

100 100 Monthly Flow (ML/month) Monthly Flow (ML/month)

10 10

1 1 3 3 15 26 38 50 62 74 85 97 15 26 38 50 62 74 85 97 Proportion of time exceeded (%) Proportion of time exceeded (%)

Flow duration curve for Glenelg River at Casterton Flow duration curve for Glenelg River at Casterton -MARCH- -APRIL- 100000 100000

Est. natural flow Est. natural flow Current Conditions Current Conditions 10000 10000

1000 1000

100 100 Monthly Flow (ML/month) Monthly Flow (ML/month)

10 10

1 1 3 3 15 26 38 50 62 74 85 97 15 26 38 50 62 74 85 97 Proportion of time exceeded (%) Proportion of time exceeded (%)

Flow duration curve for Glenelg River at Casterton Flow duration curve for Glenelg River at Casterton -MAY- -JUNE- 100000 100000

Est. natural flow Est. natural flow Current Conditions Current Conditions 10000 10000

1000 1000

100 100 Monthly Flow (ML/month) Monthly Flow (ML/month)

10 10

1 1 3 3 15 26 38 50 62 74 85 97 15 26 38 50 62 74 85 97 Proportion of time exceeded (%) Proportion of time exceeded (%)

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 48 Flow duration curve for Glenelg River at Casterton Flow duration curve for Glenelg River at Casterton -JULY- -AUGUST- 1000000 1000000

Est. natural flow Est. natural flow Current Conditions Current Conditions 100000 100000

10000 10000

1000 1000

Monthly Flow (ML/month) 100 Monthly Flow (ML/month) 100

10 10

1 1 3 3 15 26 38 50 62 74 85 97 15 26 38 50 62 74 85 97 Proportion of time exceeded (%) Proportion of time exceeded (%)

Flow duration curve for Glenelg River at Casterton Flow duration curve for Glenelg River at Casterton -SEPTEMBER- -OCTOBER- 1000000 1000000

Est. natural flow Est. natural flow Current Conditions Current Conditions 100000 100000

10000 10000

1000 1000

Monthly Flow (ML/month) 100 Monthly Flow (ML/month) 100

10 10

1 1 3 3 15 26 38 50 62 74 85 97 15 26 38 50 62 74 85 97 Proportion of time exceeded (%) Proportion of time exceeded (%)

Flow duration curve for Glenelg River at Casterton Flow duration curve for Glenelg River at Casterton -NOVEMBER- -DECEMBER- 1000000 100000

Est. natural flow Est. natural flow Current Conditions Current Conditions 100000 10000

10000

1000

100

Monthly Flow (ML/month) 100 Monthly Flow (ML/month)

10 10

1 1 3 3 15 26 38 50 62 74 85 97 15 26 38 50 62 74 85 97 Proportion of time exceeded (%) Proportion of time exceeded (%)

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 49 Flow duration curve for Wannon River at Glenelg River Flow duration curve for Wannon River at Glenelg River -JANUARY- -FEBRUARY- 100000 100000

Est. natural flow Est. natural flow Current Conditions Current Conditions 10000 10000

1000 1000

100 100 Monthly Flow (ML/month) Monthly Flow (ML/month)

10 10

1 1 3 3 15 26 38 50 62 74 85 97 15 26 38 50 62 74 85 97 Proportion of time exceeded (%) Proportion of time exceeded (%)

Flow duration curve for Wannon River at Glenelg River Flow duration curve for Wannon River at Glenelg River -MARCH- -APRIL- 100000 100000

Est. natural flow Est. natural flow Current Conditions Current Conditions 10000 10000

1000 1000

100 100 Monthly Flow (ML/month) Monthly Flow (ML/month)

10 10

1 1 3 3 15 26 38 50 62 74 85 97 15 26 38 50 62 74 85 97 Proportion of time exceeded (%) Proportion of time exceeded (%)

Flow duration curve for Wannon River at Glenelg River Flow duration curve for Wannon River at Glenelg River -MAY- -JUNE- 100000 100000

Est. natural flow Est. natural flow Current Conditions Current Conditions 10000 10000

1000 1000

100 100 Monthly Flow (ML/month) Monthly Flow (ML/month)

10 10

1 1 3 3 15 26 38 50 62 74 85 97 15 26 38 50 62 74 85 97 Proportion of time exceeded (%) Proportion of time exceeded (%)

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 50 Flow duration curve for Wannon River at Glenelg River Flow duration curve for Wannon River at Glenelg River -JULY- -AUGUST- 1000000 1000000

Est. natural flow Est. natural flow Current Conditions Current Conditions 100000 100000

10000 10000

1000 1000

Monthly Flow (ML/month) 100 Monthly Flow (ML/month) 100

10 10

1 1 3 3 15 26 38 50 62 74 85 97 15 26 38 50 62 74 85 97 Proportion of time exceeded (%) Proportion of time exceeded (%)

Flow duration curve for Wannon River at Glenelg River Flow duration curve for Wannon River at Glenelg River -SEPTEMBER- -OCTOBER- 1000000 1000000

Est. natural flow Est. natural flow Current Conditions Current Conditions 100000 100000

10000 10000

1000 1000

Monthly Flow (ML/month) 100 Monthly Flow (ML/month) 100

10 10

1 1 3 3 15 26 38 50 62 74 85 97 15 26 38 50 62 74 85 97 Proportion of time exceeded (%) Proportion of time exceeded (%)

Flow duration curve for Wannon River at Glenelg River Flow duration curve for Wannon River at Glenelg River -NOVEMBER- -DECEMBER- 100000 100000

Est. natural flow Est. natural flow Current Conditions Current Conditions 10000 10000

1000 1000

100 100 Monthly Flow (ML/month) Monthly Flow (ML/month)

10 10

1 1 3 3 15 26 38 50 62 74 85 97 15 26 38 50 62 74 85 97 Proportion of time exceeded (%) Proportion of time exceeded (%)

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 51 Flow duration curve for Glenelg River at Dartmoor Flow duration curve for Glenelg River at Dartmoor -JANUARY- -FEBRUARY- 100000 100000

Est. natural flow Est. natural flow Current Conditions Current Conditions 10000 10000

1000 1000

100 100 Monthly Flow (ML/month) Monthly Flow (ML/month)

10 10

1 1 3 3 15 26 38 50 62 74 85 97 15 26 38 50 62 74 85 97 Proportion of time exceeded (%) Proportion of time exceeded (%)

Flow duration curve for Glenelg River at Dartmoor Flow duration curve for Glenelg River at Dartmoor -MARCH- -APRIL- 100000 100000

Est. natural flow Est. natural flow Current Conditions Current Conditions 10000 10000

1000 1000

100 100 Monthly Flow (ML/month) Monthly Flow (ML/month)

10 10

1 1 3 3 15 26 38 50 62 74 85 97 15 26 38 50 62 74 85 97 Proportion of time exceeded (%) Proportion of time exceeded (%)

Flow duration curve for Glenelg River at Dartmoor Flow duration curve for Glenelg River at Dartmoor -MAY- -JUNE- 100000 1000000

Est. natural flow Est. natural flow Current Conditions Current Conditions 100000 10000

10000

1000

100

Monthly Flow (ML/month) Monthly Flow (ML/month) 100

10 10

1 1 3 3 15 26 38 50 62 74 85 97 15 26 38 50 62 74 85 97 Proportion of time exceeded (%) Proportion of time exceeded (%)

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 52 Flow duration curve for Glenelg River at Dartmoor Flow duration curve for Glenelg River at Dartmoor -JULY- -AUGUST- 1000000 1000000

Est. natural flow Est. natural flow Current Conditions Current Conditions 100000 100000

10000 10000

1000 1000

Monthly Flow (ML/month) 100 Monthly Flow (ML/month) 100

10 10

1 1 3 3 15 26 38 50 62 74 85 97 15 26 38 50 62 74 85 97 Proportion of time exceeded (%) Proportion of time exceeded (%)

Flow duration curve for Glenelg River at Dartmoor Flow duration curve for Glenelg River at Dartmoor -SEPTEMBER- -OCTOBER- 1000000 1000000

Est. natural flow Est. natural flow Current Conditions Current Conditions 100000 100000

10000 10000

1000 1000

Monthly Flow (ML/month) 100 Monthly Flow (ML/month) 100

10 10

1 1 3 3 15 26 38 50 62 74 85 97 15 26 38 50 62 74 85 97 Proportion of time exceeded (%) Proportion of time exceeded (%)

Flow duration curve for Glenelg River at Dartmoor Flow duration curve for Glenelg River at Dartmoor -NOVEMBER- -DECEMBER- 1000000 100000

Est. natural flow Est. natural flow Current Conditions Current Conditions 100000 10000

10000

1000

100

Monthly Flow (ML/month) 100 Monthly Flow (ML/month)

10 10

1 1 3 3 15 26 38 50 62 74 85 97 15 26 38 50 62 74 85 97 Proportion of time exceeded (%) Proportion of time exceeded (%)

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 53 A.7 Rocklands Reservoir discharge

Discharge from Rocklands Reservoir for past 10 years

4000

3500

3000

2500

Median 2000 20th percentile 80th percentile

Mean Discharge (ML/month) 1500

1000

500

0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 54 Appendix B Geomorphology

B.1 Introduction Sand accumulation in stream channels is a major stream management issue in the Glenelg River catchment. Sheet, rill and gully erosion of granite portions of the catchment have filled the Glenelg and its tributaries with about 6,000,000 m3 of sand (Rutherfurd and Budahazy, 1996). Little sand is now coming from the catchment, so the major source of sand to the Glenelg River is the lower reaches of tributary streams. The tributaries introduce discrete slugs of sand to main channel that often partially dam the river. As these sand ‘slugs’ move downstream they attenuate, gradually giving way to a succession of small ‘sluglettes’. Rutherfurd and Budahazy (1996) estimate the sand slugs are moving through the stream network at a slow rate, with only tens of thousands of cubic metres being removed by bedload transport. The low transport rate is due, in part, to regulation of the river from Rocklands Reservoir.

Near Dartmoor the river has well vegetated banks but is affected by sediment input (Figure 26). The sediment has created a sandy bed with few deep holes. Sites where sediment build-up is most obvious are around Casterton and Harrow. The lower section in the Lower Glenelg National Park is in good condition with excellent bank and verge vegetation (Figure 29).

B.2 Stream network The Glenelg River rises in the Grampians and flows to the Southern Ocean. On leaving the Grampians, between Rocklands Reservoir and Casterton, the river flows along the northern and then the western edge of the Dundas Tablelands. Near Casterton the Wannon River joins the Glenelg River and from here the Glenelg River meanders across the broader coastal plains towards Dartmoor. Below Dartmoor the river follows a generally southerly course becoming increasingly incised in limestone (Erskine, 1994). At the confluence of Moleside Creek the river turns WNW and runs parallel to the coast, eventually looping into South Australia before entering the sea at Nelson.

The catchment boundary follows the state border quite closely in the west but swings eastwards at to abut the Wimmera region in the north. The boundary swings towards the south at the Grampians then winds its way in a southwesterly direction back to the coast. The catchment is approximately 120 km wide and 100 km from north to south, covering a total area of 1,266,030 ha (Department of Water Resources Victoria, 1989).

The topography of the catchment varies substantially from the coastal plains in the southwest to the rugged escarpments of the Grampians in the northeast. The Victoria and Serra Ranges of the Grampians drain into both the Glenelg and the Wannon Rivers; the former of which ultimately drains the north and west of the catchment and the latter the east and south. The cental portion of the catchment is composed of the deeply dissected Dundas and Merino tablelands. Towards the southeast the tablelands drop down to the flat basal plains around Hamilton. Near Nelson there is an estuarine lagoon at the mouth of the Glenelg River and a line of calcereous sand dunes fringes the coastline. During low flow conditions salt water penetrates upstream beyond the boundary of the Lower Glenelg National Park. At over 70 km, the Glenelg estuary one of the State’s longest (Sherwood et al. 1998).

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 55 Mitchell (1990) reported that the river down to about Dartmoor is generally in poor to moderate condition. Riparian vegetation is continuous to discontinuous along both banks of the river but is generally restricted to the bank crest fringe (Sherwood et al. 1998). Near Dartmoor the river has well vegetated banks but is affected by sediment input. The sediment has created a sandy bed with few deep holes. Sites where sediment build-up is most obvious are around Casterton and Harrow. The lower section in the Lower Glenelg National Park is in good condition with excellent bank and verge vegetation.

In their more complete description of the Glenelg River channel, Rutherfurd and Budahazy (1996) divide the river into four reaches: 3) Rocklands to Fulham Bridge (30 km); 4) Fulham Bridge to Killara Bridge (120km); 5) Killara Bridge to Dartmoor (30 km); and 6) the estuarine section (65 km).

B.3 Hydrology Rainfall varies seasonally and spatially within the catchment. While winter months are wetter throughout the catchment, there is a gradual decline in mean annual rainfall from the coast near Nelson (approximately 750 mm) to the centre of the catchment (approximately 550 mm). In the northeast of the catchment, in the vicinity of the Grampians, annual rainfall increases with elevation to more than 900 mm on the Victoria Range. Rainfall is relatively reliable along the coast and in the higher parts of the Grampians (Department of Water Resources Victoria, 1989).

Reflecting rainfall distribution, flows are strongly seasonal with 70% of average annual flow in the Glenelg River above the Wannon River junction occurring in the three months August to October. At Dartmoor (Station No. 238 206), the residual mean annual flow of the Glenelg River is 639,000 ML. Although only 1.5 % of that total occurs in the months January to March, there are reliable base flows rarely falling below 30 ML per day.

The Glenelg River, under natural conditions, commonly dried up at Balmoral over the three months February to April, sometimes for months longer. Flows at Balmoral are now highly regulated by Rocklands Reservoir. Rocklands has a storage capacity about three times its average annual inflow and very rarely spills. However, releases from Rocklands Reservoir do not appear to exert an influence below Casterton (Mitchell et al. 1996). Under low flow conditions transit times for releases from Rocklands are approximately 7 days to Balmoral, 14 days to Fulham Bridge and 21 days to Harrow. According to Mitchell et al. (1996) a 20-25 ML/day release at Rocklands delivers 10 ML/day at Fulham Bridge and 2 ML/day at Harrow.

B.4 Landuse The Department of Water Resources Victoria (1989) reports that European settlement of the Glenelg catchment began in 1837. The merino wool industry was established quickly and today wool is still the main product of the region with prime lamb production also important. The beef industry is well established and dairying has been steadily declining. Since 1837, two-thirds of the catchment has been cleared for pasture to graze sheep and cattle and today only two main forested areas remain. The northeast of the catchment is forested and includes the Grampians National Park, as

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 56 well as State Forest where hardwood is logged. In the west there is a mixture of native hardwood forests (the Glenelg National Park) and intensive softwood plantations (Department of Water Resources Victoria, 1989).

Hamilton is the major urban centre within the catchment, located in the southeast.

B.5 Sand slugs The following discussion of sediment transport/storage in the Glenelg River is drawn from Rutherfurd and Budahazy (1996).

Before European settlement, the upper Glenelg River and its tributaries were characterised by pools separated by densely vegetated reaches. Below Harrow, vegetated reaches were less common but there were still deep pools. Since the 1850s, gullying and sheet erosion of granite portions of the catchment have filled long reaches of the Glenelg and its tributaries with sand. The sand is moving through the stream network in a complicated pattern, but it will take many decades for the sand to be stabilised and removed (Rutherfurd and Budahazy 1996).

Rutherfurd and Budahazy estimate that there are between 4 and 8 million cubic metres of sand stored in the Glenelg River and its tributaries. Channel storage estimates range from about 50,000 m3/km in the Glenelg at Harrow, to an average of about 10- 20,000 m3/km elsewhere in the system. The sand occupies a larger proportion of the cross-section in the tributaries (up to 80%) than in the Glenelg River. Capacity loss in the Glenelg River falls from about 60% between Harrow and Burkes Bridge, to 20% at Casterton, and 10% at Dartmoor.

Most of the sand was deposited in the lower reaches of the streams very quickly after the onset of channel extension through gullying. The 1946 flood was particularly effective at moving the sediment through the system. However, the original deep pools in the Glenelg River, combined with regulation from Rocklands Reservoir, have limited the movement of sand through the trunk stream. As a result, sand in the Glenelg River is stored in discrete slugs originating from several tributary streams: Mathers, Deep, and Pigeon Ponds Creeks, Chetwynd, Wando, and Wannon Rivers.

There is no doubt that the major period of catchment and gully erosion has passed in the Glenelg River catchment, and that soil conservation activities have contributed to a reduced erosion rate. However, the sand slugs in the lower tributaries are still on their rising limb, or close to their peaks. Sand located in the lower few kilometres of tributary streams are now the major store of sand in the catchment. There are no large reserves of sand moving through stream networks towards the Glenelg River (with the possible exception of the Chetwynd River).

Of the sand already stored in the main channel, only about two-thirds will be available for downstream transport. About one-third will be more permanently stored in benches, pointbars or on the floodplain. Importantly, in smaller tributaries, large volumes of sand are stored in deep areas of the bed that have been abandoned by widening of the channel. In Bryans Creek and Pigeon Ponds Creek, this bed storage has removed up to half of the total volume of sand available for transport.

The effect of the movement of sand into the Glenelg River and its tributaries is not clear. Rainfall-runoff modelling suggests that filling half of the channel cross-section

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 57 with sand will have minimal impact on the size of flood peaks or their time-to-peak because of the decreased roughness associated with sand sheets. In addition, deposition on the floodplain has meant that in many reaches the rise in bed level has been matched by an increase in bank height.

The available evidence suggests that the present distribution of sand in the Glenelg catchment was in place by the 1940s and has changed very little over the past half century. Discrete sand slugs below the Wannon River junction have remained in the same position since 1947. Contrary to earlier estimates of huge bedload transport rates in the Glenelg River, (hundreds of thousands of tonnes per year), several lines of evidence suggest that bedload transport rates are in the order of 10-30,000 m3/year. The major tributaries transport less than 5000 m3/year.

A major flood could move large volumes of sand. This certainly occurred in the 1946 flood when large volumes of sand were deposited in the channel and on the floodplain. However, regulation has dramatically reduced the frequency of large floods (I. Rutherfurd, pers. comm.), and so the rate of sand transport.

Sand slugs buffer channel morphology from hydrological changes in the catchment. Hydrology has changed because of catchment clearing, and because gully development has increased the efficiency of the drainage network. As sand moves through a stream reach, the channel is exposed to the changed hydrological conditions of the catchment, and typically adjusts to the new flow regime by incising. Such incision also leads to incision of the tributaries, particularly if those tributaries are graded to the elevation of the sand surface.

Moreover, removal of the sand that fills some channels in the Glenelg catchment to one-third or half of their depth has implications for bank stability. This sand has supported the bank and reduced the incidence of bank failure. The movement of sand out of a reach and any subsequent incision of the bed can heighten the banks and cause the onset of slumping.

B.6 Summary Sand accumulation in stream channels is the major stream management issue in the Glenelg River catchment. The sediment influx has smothered the previous channel form and dramatically simplified the geomorphological diversity of the channel by creating a sandy bed with few deep holes. The sand is moving through the stream network in a complicated pattern, but it will take many decades for the sand to be stabilised and removed. The available evidence suggests that the present distribution of sand in the Glenelg catchment was in place by the middle of last century and has changed very little over the intervening 50 years. However, a large flood could re- work and transport large volumes of sand as occurred during the 1946 flood. The effect of regulation has limited the magnitude and frequency of floods downstream from Rocklands Reservoir.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 58 Appendix C Water quality

Water Quality can be characterised by a large variety of parameters, many of which are important to the ecological condition of a waterway. Key parameters for the monitoring of water quality include salinity, DO, nutrients, pH and turbidity. These parameters are important as they influence ecological processes and water use. For example, low levels of dissolved oxygen can restrict aerobic respiration resulting in stress to or mortality of aquatic biota. Similarly, high turbidity levels can restrict the use of water for irrigation through reducing the efficiency of irrigation pumps and high nutrient levels can result in algal blooms that make the water unsuitable for consumption.

Numerous sites have been established throughout the Glenelg catchment for the purposes of water quality monitoring. Ten sites are still active along the Glenelg River and its tributaries and of these 5 have been selected for the analysis of water quality along the river system. These are (progressing downstream): q Glenelg River at Big Cord (238 231), upstream of Rocklands Reservoir; q Glenelg River at Fulham Bridge (238 224), about 20km downstream of Rocklands Reservoir; q Wannon River at Henty (238 228), about 15km upstream of the confluence with the Glenelg River; q Glenelg River at Sandford (238 202), immediately downstream of the Wannon River confluence; and, q Glenelg River at Dartmoor (238 206).

All data presented in this document has been sourced from the Victorian Water Quality Monitoring Network (VWQMN). Three sets of data have been discussed. Firstly, the results presented in the VWQMN Annual Report, 1998 (AWT 1999) are presented as these indicate the compliance of each parameter with selected guidelines. To supplement this, percentiles have been calculated on the past 10 full years of data (1990-1999), therefore where data is presented for the previous 3 years or 10 years this is prior to and including 1999 (VWQMN 1999). Thirdly, monthly percentile plots showing seasonal variation of selected parameters is also presented. All values are discussed in relation to the guidelines set out in the VWQMN Annual Report (AWT 1999).

The VWQMN Annual Report presents attainment values (with the set guideline) for each water quality parameter. Attainment is the frequency (% occurrence) that a particular water quality parameter falls within developed guidelines for a specific site. For example, if pH was to have an attainment of 20%, this indicates that 20% of the total number of values for a specified time period were within the guidelines specified. Attainment values are described as either high (> 95%), moderate (90-95%) or low (< 90%) (AWT 1999).

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 59 C.1 Salinity Salinity or electrical conductivity (EC) is a measure of the salt content of the water. High EC can threaten the survival of native flora and fauna as well as affect the use of the water for drinking and irrigation. Aquatic biota are adapted to tolerate a certain salinity range. Conditions outside this tolerable range can create stressful conditions that may lead to reduced biodiversity and biomass through the exclusion of species or even mortality. There are a number of factors that may contribute to high EC values, however if EC is already moderate, evaporation can increase the EC by removing a large proportion of water while leaving the dissolved salts behind. The guideline value for EC varies depending on the use of the water, however for the protection of the aquatic environment, EC values should not exceed 1500 mS/cm for any period of the year. Attainment of the electrical conductivity during 1998 with the ANZECC guidelines decreased with distance downstream. Attainment at Big Cord was 100% and 33% attainment was achieved at Fulham Bridge, while the remaining two sites on the Glenelg River and that on the Wannon River achieved 0% attainment, indicating that at no time was a record collected that was less than 1500 mS/cm (AWT 1999). This increase in salinity with distance downstream was consistent with findings by Mitchell (1990).

Median EC values for the past 10 years increase with distance downstream, peaking at Sandford and then decrease slightly at Dartmoor. Median and 90th percentile values at Big Cord have always been recorded within the ANZECC guideline for the past 10 years. In contrast the median values have exceeded the guideline value at all sites during all but one year at Fulham Bridge. During 1993 EC was 1300 mS/cm at Fulham Bridge. Salinity varies little at Big Cord, while that for the other four sites varies greatly throughout the year. Salinity in the Wannon River at Henty and at both Sandford peaks during March when flushing flows are lowest. The peak in salinity at Dartmoor is greatest during May. The lowest median and greatest variation in salinities, as shown by the variation between the 10th and 90th percentiles, occurs when flows are lowest, between September and October. In contrast, salinity at Fulham Bridge exhibits an inverse pattern that possibly coincides with high volume releases from Rocklands Reservoir. Discharge from Rocklands Reservoir is greatest during February-March and lowest during August (Figure C.7). Salinity peaks during September and is lowest during May. There has not been any long term change in electrical conductivity for the past 20 years at any site (Mitchell 1990).

Salinity varies along the length of the Glenelg River, with saline pools present at specific locations. A major source of salt in the Glenelg River is saline groundwater (Glenelg Regional Catchment Strategy, 1997). Under low flow conditions, groundwater plays an important role in determining salinity along the entire river length. At higher flows, surface water dilutes the effect of groundwater on salinity (Sherwood et al. 1998a). A decrease in salinity that occurs between Myaring Bridge to Dartmoor, approximately 20km downstream, is likely to be due to dilution that results from inflow of less saline surface or groundwater.

The section of the Glenelg River between Rocklands Reservoir and Fulham Bridge is characterised by shallow sections of less than 3 m deep interspersed with deep elongated pools up to 8.5 m in depth (Sherwood et al. 1998a). This section of the river has been identified as a major source of salt with salinity increasing with increasing distance downstream from Rocklands Reservoir (Sherwood et al. 1998a).

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 60 A long-lived saline pool is present just upstream of Fulham Bridge. The water depth, conductivity and dissolved oxygen profile showed little change between September 1990 to March 1991. The bottom 3 metres of the pool had conductivity levels exceeding 10000 mS/cm with associated low dissolved oxygen. The surface 2-2.5 m showed variation in temperature but with little change in the underlying water (McGuckin et al. 1991).

In the 15km section downstream of Rocklands Reservoir, surface and bottom salinities were between 3500 mS/cm and 7000 mS/cm with surface salinities approximately 2000 mS/cm less than that at the bottom. Further downstream, conductivity declined to approximately 2000 mS/cm with the exception of Fulham Bridge, where bottom conductivity was 10380 mS/cm. In the reach between Casterton and Dartmoor, a 1991 survey revealed no significant difference in surface and bottom salinities (McGuckin et al. 1991).

Deoxygenation also prevailed in the section of the river between Rocklands Reservoir and Fulham Bridge with lowest concentrations of dissolved oxygen coinciding with high bottom conductivities (McGuckin et al. 1991).

The high salinity in the Glenelg River is of particular concern in the upper reaches of the river near Fulham Bridge. The presence of saline pools is also closely associated with adverse temperature and dissolved oxygen conditions. The persistence of such conditions greatly affects the amount of suitable available habitat for aquatic organisms.

C.2 Nutrients High values of nitrogen and or phosphorus produces nutrient enrichment, increasing plant and animal biomass, benefiting certain species and potentially altering species diversity and abundance in affected systems. Eutrophication may result if nutrient levels get sufficiently high and other conditions are favourable. Under eutrophic conditions, waters can become anoxic, and turbidity becomes high, potentially leading to algal blooms and fish kills (OCFE 1988). The attainment of total nitrogen in the Glenelg River (TN) records with the ANZECC guideline of <0.75 mg/L (ANZECC 1992) decreased with distance downstream during 1998. The lowest attainment in the Glenelg River was at Dartmoor (25%), while the lowest attainment of 8% was recorded on the Wannon River at Henty. Attainment at Big Cord during 1998 was 92%. Attainment with the EPA guideline of 1.0 mg/L was similar with decreasing attainment with distance downstream on the Glenelg River and the lowest attainment of 50% recorded at Henty. Percentile values at Big Cord, however did not exceed the guideline during any of the past 10 years. A general increase in median TN values was also exhibited with distance downstream. Median TN at Henty and Sandford was within the ANZECC guideline value on two occasions only in the past 10 years and four times at Dartmoor. Median TN values only exceeded the EPA guideline during 1990-92, at Dartmoor. Annual fluctuation of total nitrogen varies greatly between sites (Appendix C). Similar to salinity, total nitrogen varies little at Big Cord. Variation in total nitrogen values is also minor at Fulham Bridge although values are consistently greater. The greatest variation in TN occurs at the Henty, Sandford and Dartmoor. Total Nitrogen peaks during July but remains high until October, while at Sandford and Dartmoor the peak is exhibited during September. The peak in TN values is possibly correlated with high runoff.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 61 Attainment with the ANZECC guideline for total phosphorus (TP) of <0.1 mg/L during 1998 was 100% at all sites presented , while attainment with the EPA guideline of 0.035 mg/L decreased with distance downstream and was lowest at Henty (50%). (AWT 1999). Similar to TN, there is a general increase in median TP with distance downstream. Median TP values have consistently been within the ANZECC guideline at all sites over the past 10 years. While exceedance of the EPA guideline was most frequent at Sandford. The 90th percentile values for TP have exceeded the ANZECC guideline value during three years at Henty and Dartmoor and four years at Sandford. As has been shown with the above parameters in the Glenelg River, seasonal variation in TP is similar at Henty, Sandford and Dartmoor (Appendix C). At Big Cord and Fulham Bridge median TP remains low for much of the year. In contrast, median TP peaks during September at Sandford and Dartmoor, and during August at Henty. The peaks in TP possibly correlate to patterns of runoff.

Nutrient enrichment of the waterways has been recognised as a significant issue. To date there have been no blue green algal blooms reported in the Glenelg River although eutrophication of farm dams and lakes has been recorded (Dixon et al. 1998). Blooms have, however been recorded in Rocklands Reservoir (1991) and the Casterton Sewage Treatment Ponds (1995) (GRCLPB 1997).

Sources of nutrients within the Glenelg River are varied. Active erosion in the subcatchment of Sandford contributes to nitrogen loads but not phosphorus. Nitrogen may be from decaying organic material and animal wastes. Until 1996/97, the Casterton Wastewater Treatment Plant was contributing an unknown load of nutrients to the river, which would be having a major impact. This practice has now ceased (Wagg 1997). Septic tank effluent at Dartmoor may also contribute to nitrogen concentrations in the river (Sherwood et al. 1998a). At Dartmoor, TKN associated with organic material is also positively related to flow, similarly for TP, which is attached to sediments (Wagg 1997).

Although TP rarely exceeds the guideline values in the Glenelg River, values of TN progressively exceed guideline values with distance downstream. The occurrence of high nitrogen values can potentially lead to the growth of algal blooms and development of anoxic conditions.

C.3 pH The acidity of a waterway is measured by its pH. Reduced pH values are associated with more acidic conditions in a river. The chemical properties of water can be altered by the pH. Spawning failure and diminished hatching success for fish has been associated with pH values less than 6.0 (ANZECC 1992). Macroinvertebrate communities generally have reduced numbers, fewer species and altered species composition at lower pH values. The SEPP Waters of Victoria (1988) guidelines for pH are 6.0 to 9.0. During 1998 there was 100% attainment with the SEPP guidelines for pH at the four of the five sites presented. Glenelg River at Big Cord had an attainment of only 33% during this period. Attainment with the ANZECC guideline of 6.5-9.0 was only 17% at Big Cord but 100% at the remaining sites (AWT 1999). Median pH values have only been outside the two guidelines at Big Cord where water was slightly acidic. During the past 10 years, 10th and 90th percentile pH values have consistently been within the ANZECC guideline at the four sites downstream from Rocklands Reservoir. At Big Cord, pH values demonstrate slightly acidic conditions with median values being greater than or equal 6.0 during only 4 of the past 10 years.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 62 This indicates that pH is not an issue in terms of water quality in the Glenelg River below Rocklands Reservoir.

C.4 Dissolved oxygen There are a variety of natural and human activities that contribute to reduced concentrations of dissolved oxygen (DO) including pollutants and bacterial activity in enriched sediments (OCFE 1988). Low DO can also be expected in slow moving or still waters. Low DO concentrations can be harmful to aquatic biota, as it is required for aerobic respiration. The SEPP Waters of Victoria guideline for DO is a concentration that exceeds 5 mg/L for general surface waters. Attainment of 100% was achieved at all sites during 1998 (AWT 1999). With the exception of Fulham Bridge during 1993, all 10th percentile values of DO have been greater than this guideline value for the past 10 years. Median DO values vary throughout the year generally peaking in the middle of the year (Appendix C). The earliest peak in median DO occurs during May at Big Bend while at the other four sites this parameter peaks between June and July, Sandford does however have an additional spike during March. The lowest peaks in median DO have been exhibited at Big Cord and Fulham Bridge. The peak in DO prior to the high flow period of September to October may be as a result of water temperature. During periods of low water temperature the water holds oxygen better, therefore although mixing is not at its maximum during this period, the potential for the water to hold oxygen is at its optimum.

Severe deoxygenation has been found throughout the length of the Glenelg River. Severe deoxygenation is closely associated with the presence of saline pools and has been recorded in the reach from Rocklands Reservoir to Fulham Bridge with each pool registering a bottom dissolved oxygen concentration of less than 10% saturation. Sites between Casterton and Dartmoor were only slightly better during a 1991 survey with values ranging between 10-40% saturation (McGuckin et al. 1991). It is suggested that the temperature gradients in this section of the river are most likely associated with the depth of the pool and are the governing factor controlling DO at conductivities less than 500 mS/cm. Conversely, pools between Casterton and Dartmoor had no significant difference in surface and bottom salinity (McGuckin et al. 1991).

Although low dissolved oxygen does not appear to be of concern at the VWQMN sampling sites, isolated locations do exhibit low DO concentrations. Of particular concern is the significant reduction in DO in the deep pools along the Glenelg River, especially in the reach from Rocklands Reservoir to Fulham Bridge.

C.5 Turbidity Increased turbidity limits the penetration of light through the water in the river thereby reducing the growth of aquatic flora and impeding the feeding of visual predators, such as some fish species. There are not any SEPP or ANZECC guidelines for turbidity but those from the Office of the Commissioner for the Environment (1988) indicate a range of guideline values that vary depending on the area. Degraded, in a mountain area, relates to a turbidity value of >12.5 NTU, >22.5 NTU a valley and on a plain >30.0 NTU, values less than these indicate better water quality with respect to turbidity. Median turbidity values have been recorded as excellent for the past 10 years at all sites presented. The 90th percentile values for turbidity at Henty, Dartmoor and Sandford have frequently been recorded greater than 30.0 NTU indicating

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 63 degraded conditions that correlates with periods of high flow (winter) and hence runoff (Department of Water Resources Victoria 1989). Turbidity at Fulham Bridge has been shown to correlate positively with discharge at flows greater than 10 ML/day (Mitchell et al. 1996). Turbidity is not a of concern in the Glenelg River system as the winter high turbidities return to acceptable levels.

C.6 Summary This analysis indicates that water quality in the Glenelg River system is poor with respect to electrical conductivity. Electrical conductivity is particularly high in pools in the reach of the Glenelg River between Rocklands Reservoir and Fulham Bridge. Although turbidity and nutrients are generally not high, historical levels have been shown to get high and hence may impact on the aquatic biota. Low concentrations of dissolved oxygen is not of concern at a river wide scale but decreases in DO in the saline pools is a factor that may inhibit the occurrence of some species in the areas of the river where they persist. The concentrations of some parameters are closely related to river flow. Clear patterns in nutrients and salinity can be observed during high flow periods

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 64 C.7 Water quality plots indicating guideline values

Glenelg River @ Big Cord (238231) - Salinity

6500

6000

5500

5000

4500

4000

3500 Median 10th Percentile 3000 90th Percentile

2500

2000

1500 Guideline 1500 mS/cm 1000

500

0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Glenelg River @ Big Cord (238231) - Total Nitrogen

2.5

1.5

Median 10th Percentile 90th Percentile 1 EPA ANZECC

0.5

0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 65 Glenelg River @ Big Cord (238231) - Total Phosphorus

0.18

0.16

0.14

0.12 ANZECC

0.1 Median 10th Percentile 0.08 90th Percentile

0.06

0.04 EPA

0.02

0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Glenelg River @ Big Cord (238231) - Dissolved Oxygen

8 Median 10th Percentile 90th Percentile 6 Guideline 5 mg/L 4

0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 66 Glenelg River @ Fulhams Bridge (238224) - Salinity

6500

6000

5500

5000

4500

4000

3500 Median 10th Percentile 3000 90th Percentile

2500

2000

1500 Guideline 1500 mS/cm 1000

500

0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Glenelg River @ Fulhams Bridge (238224) - Total Nitrogen

2.5

1.5

Median 10th Percentile 90th Percentile 1 EPA ANZECC

0.5

0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 67 Glenelg River @ Fulhams Bridge (238224) - Total Phosphorus

0.18

0.16

0.14

0.12 ANZECC 0.1 Median 10th Percentile 0.08 90th Percentile

0.06

0.04 EPA

0.02

0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Glenelg River @ Fulhams Bridge (238224) - Dissolved Oxygen

8 Median 10th Percentile 90th Percentile 6 Guideline 5 mg/L 4

0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 68 Wannon River @ Henty (238228) - Salinity

6500

6000

5500

5000

4500

4000

3500 Median 10th Percentile 3000 90th Percentile

2500

2000

1500 Guideline 1500 mS/cm 1000

500

0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Wannon River @ Henty (238228) - Total Nitrogen

2.5

1.5 Median 10th Percentile

mg/L 90th Percentile 1 EPA ANZECC

0.5

0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 69 Wannon River @ Henty (238228) - Total Phosphorus

0.18

0.16

0.14

0.12 ANZECC

0.1 Median 10th Percentile 0.08 90th Percentile

0.06

0.04 EPA

0.02

0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Wannon River @ Henty (238228) - Dissolved Oxygen

8 Median 10th Percentile 90th Percentile 6 Guideline 5 mg/L 4

0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 70 Glenelg River @ Sandford (238202) - Salinity

6500

6000

5500

5000

4500

4000

3500 Median 10th Percentile 3000

EC Units 90th Percentile

2500

2000

1500 Guideline 1500 mS/cm 1000

500

0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month

Glenelg River @ Sandford (238202) - Total Nitrogen

2.5

1.5 Median 10th Percentile

mg/L 90th Percentile 1 EPA ANZECC

0.5

0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 71 Glenelg River @ Sandford (238202) - Total Phosphorus

0.18

0.16

0.14

0.12 ANZECC

0.1 Median 10th Percentile 0.08 90th Percentile

0.06

0.04 EPA

0.02

0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Glenelg River @ Sandford (238202) - Dissolved Oxygen

8 Median 10th Percentile 90th Percentile 6 Guideline 5 mg/L 4

0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 72 Glenelg River @ Dartmoor (238206) - Salinity

6500

6000

5500

5000

4500

4000

3500 Median 10th Percentile 3000

EC Units 90th Percentile

2500

2000

1500 Guideline 1500 mS/cm 1000

500

0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month

Glenelg River @ Dartmoor (238206) - Total Nitrogen

2.5

1.5 Median 10th Percentile

mg/L 90th Percentile 1 EPA ANZECC

0.5

0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 73 Glenelg River @ Dartmoor (238206) - Total Phosphorus

0.18

0.16

0.14

0.12 ANZECC

0.1 Median 10th Percentile 0.08 90th Percentile

0.06

0.04 EPA

0.02

0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Glenelg River @ Dartmoor (238206) - Dissolved Oxygen

8 Median 10th Percentile 90th Percentile 6 Guideline

4 5 mg/L

0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 74 n Table 6-2: Basic statistics for water quality parameters for the year 1999, collected, progressively downstream, in the Glenelg River catchment as part of the Victorian Water Quality Monitoring Network (Rivers and Streams). a) Glenelg River at Big Cord (238231). 238231 Statistic 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 EC Median 115 105 100 110 105 100 105 98 97 105 10th Percentile 101 98 92 99 95 93 100 91 87 86 90th Percentile 139 110 119 139 119 147 120 110 109 149 TN Median 0.202 0.202 0.252 0.302 0.202 0.204 0.203 0.192 0.226 0.259 10th Percentile 0.202 0.052 0.102 0.112 0.112 0.102 0.102 0.103 0.183 0.183 90th Percentile 0.251 0.208 0.302 0.302 0.292 0.327 0.261 0.312 0.371 0.393 TP Median 0.002 0.002 0.004 0.004 0.003 0.009 0.010 0.008 0.007 0.012 10th Percentile 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.005 90th Percentile 0.002 0.006 0.011 0.009 0.010 0.011 0.027 0.012 0.012 0.018 pH Median 6.3 5.5 5.2 5.8 6.5 6.0 6.9 5.8 5.6 5.6 10th Percentile 5.7 5.1 4.9 5.0 5.7 5.4 5.6 5.6 5.1 5.0 90th Percentile 6.8 7.2 5.8 6.1 7.1 6.7 7.6 6.6 6.5 6.4 DO Median 9.1 9.6 8.7 8.4 9.5 9.2 9.0 8.9 9.1 9.3 10th Percentile 8.3 8.1 7.4 7.6 8.7 8.5 7.9 8.2 7.4 8.1 90th Percentile 10.9 10.7 10.5 9.7 10.6 9.7 10.2 10.9 10.0 9.8 Turbidity Median 2.3 1.8 2.4 3.1 2.2 2.2 2.0 2.2 2.0 1.6 10th Percentile 1.6 1.3 1.5 1.6 1.6 1.6 1.5 1.2 1.4 1.2 90th Percentile 3.3 3.1 5.3 5.7 4.8 3.7 3.8 3.4 2.8 2.6 b) Glenelg River at Fulham Bridge (238224) 238224 Statistic 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 EC Median - 2450 1700 1300 2350 2950 1600 2000 1900 2600 10th Percentile - 1330 637 612 1220 1730 973 1110 964 1300 90th Percentile - 3100 3160 2920 4500 3290 3830 3390 3430 4400 TN Median - - - 0.757 0.704 0.882 0.807 0.588 0.653 0.563 10th Percentile - - - 0.714 0.403 0.803 0.536 0.506 0.516 0.520 90th Percentile - - - 0.799 1.186 1.398 1.469 0.843 0.802 0.741 TP Median - - - 0.018 0.012 0.016 0.024 0.017 0.014 0.015 10th Percentile - - - 0.017 0.009 0.015 0.014 0.007 0.011 0.012 90th Percentile - - - 0.018 0.021 0.023 0.059 0.026 0.023 0.019 pH Median - 7.4 7.2 6.9 7.0 7.1 7.0 7.4 7.1 7.1 10th Percentile - 7.2 6.7 6.4 6.6 6.7 6.9 7.0 6.8 6.9 90th Percentile - 7.7 7.8 7.2 7.4 7.6 7.4 7.7 7.4 7.3 DO Median - 7.1 8.0 7.9 8.0 7.7 8.0 8.3 7.9 8.6 10th Percentile - 5.7 6.1 3.7 6.1 6.5 5.6 6.2 6.5 7.1 90th Percentile - 8.6 9.0 9.5 9.7 9.0 8.8 9.7 10.0 9.7 Turbidity Median - 1.9 2.3 3.1 2.6 2.3 2.1 1.8 2.2 1.4 10th Percentile - 0.8 1.0 2.0 1.6 1.5 1.3 1.3 1.4 0.7 90th Percentile - 12.9 19.4 10.9 4.0 7.5 27.9 2.3 2.8 1.7 c) Wannon River at Henty (238228) 238228 Statistic 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 EC Median 4300 4200 3200 2850 4500 3600 4400 4650 4850 4950 10th Percentile 2220 1490 658 1460 3730 917 923 4210 3230 4400 90th Percentile 5400 5090 5360 4690 5090 5760 5280 5290 5700 5300 TN Median 0.930 0.731 1.085 0.967 0.710 0.920 1.026 0.781 0.986 0.860 10th Percentile 0.845 0.611 0.614 0.671 0.605 0.849 0.626 0.654 0.859 0.574 90th Percentile 1.738 2.089 1.930 1.558 1.014 1.924 1.901 0.951 1.392 1.008 TP Median 0.041 0.021 0.058 0.036 0.020 0.028 0.034 0.022 0.035 0.030 10th Percentile 0.023 0.010 0.011 0.012 0.013 0.018 0.020 0.013 0.022 0.022 90th Percentile 0.083 0.073 0.158 0.078 0.062 0.136 0.120 0.054 0.084 0.056 pH Median 8.0 8.0 7.9 7.8 7.8 7.8 8.0 8.2 8.0 8.1 10th Percentile 6.8 7.5 7.4 7.4 7.0 7.2 7.3 8.0 7.9 7.6 90th Percentile 8.2 8.3 8.0 8.0 8.1 8.2 8.4 8.2 8.2 8.3 DO Median 9.3 9.8 8.4 9.6 9.7 9.3 8.7 9.4 9.3 9.9 10th Percentile 8.5 8.3 7.4 7.8 8.5 7.4 7.7 8.6 8.2 8.0 90th Percentile 11.0 10.9 11.1 10.4 11.2 10.7 11.4 11.1 10.7 11.2 Turbidity Median 4.2 6.9 16.0 11.4 5.6 8.0 7.6 3.2 4.5 3.2

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 75 238228 Statistic 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 10th Percentile 2.5 2.7 2.4 2.7 2.2 2.4 1.3 1.9 2.9 1.7 90th Percentile 42.0 37.0 54.2 32.7 15.2 50.7 56.9 13.2 17.3 6.0 d) Glenelg River at Sandford (238 202). 238202 Statistic 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 EC Median 3950 4000 2300 2450 4400 3850 4200 4050 4050 4500 10th Percentile 2310 1610 628 928 3600 927 977 3710 3150 3900 90th Percentile 4700 5080 5500 4570 4700 6310 5550 4390 4980 5090 TN Median 0.889 0.706 0.900 0.873 0.690 0.958 0.808 0.652 0.763 0.650 10th Percentile 0.595 0.555 0.615 0.560 0.512 0.772 0.582 0.574 0.666 0.529 90th Percentile 1.648 1.784 1.765 1.345 1.089 2.259 2.181 0.875 1.159 0.899 TP Median 0.036 0.030 0.049 0.036 0.032 0.053 0.050 0.022 0.036 0.024 10th Percentile 0.021 0.018 0.029 0.026 0.016 0.026 0.019 0.009 0.026 0.016 90th Percentile 0.089 0.066 0.137 0.102 0.067 0.136 0.145 0.053 0.063 0.042 pH Median 7.9 8.2 8.1 7.9 8.0 7.8 7.9 8.0 8.0 8.1 10th Percentile 6.8 7.6 7.4 7.4 7.3 7.0 7.2 7.9 7.8 7.6 90th Percentile 8.2 8.5 8.3 8.3 8.5 8.4 8.2 8.3 8.1 8.2 DO Median 10.4 10.3 10.8 10.2 11.1 9.7 9.3 9.9 9.8 9.9 10th Percentile 8.7 8.3 7.8 7.8 9.2 7.7 7.5 7.7 8.9 8.8 90th Percentile 11.5 14.3 11.6 11.6 11.6 11.7 10.6 11.9 11.1 10.9 Turbidity Median 5.2 4.5 5.6 9.2 2.6 4.4 5.4 2.9 2.9 2.7 10th Percentile 1.7 2.0 1.9 2.0 2.1 2.2 1.6 1.6 2.3 1.6 90th Percentile 38.5 49.6 58.0 40.0 14.0 52.3 52.0 16.7 13.6 6.4 e) Glenelg River at Dartmoor (238 206). 238206 Statistic 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 EC Median 2550 2800 2950 1950 3000 2500 2750 3350 2900 3550 10th Percentile 1810 1320 687 1250 2420 1760 904 2700 2600 3020 90th Percentile 3690 3670 3670 3180 3690 4020 3980 3790 3660 3890 TN Median 1.010 1.005 1.115 0.900 0.735 0.995 0.960 0.725 0.882 0.710 10th Percentile 0.642 0.599 0.659 0.711 0.634 0.682 0.668 0.642 0.700 0.590 90th Percentile 1.560 1.605 1.494 1.646 0.978 1.658 2.399 0.879 1.351 0.866 TP Median 0.026 0.023 0.039 0.024 0.013 0.022 0.028 0.020 0.021 0.025 10th Percentile 0.014 0.009 0.010 0.010 0.009 0.010 0.013 0.008 0.008 0.015 90th Percentile 0.106 0.092 0.095 0.106 0.028 0.087 0.156 0.030 0.069 0.045 pH Median 7.7 7.8 7.7 7.7 7.6 7.7 7.3 7.8 7.6 7.6 10th Percentile 6.4 7.6 7.5 7.2 7.0 7.4 6.4 7.7 7.0 7.4 90th Percentile 7.9 8.0 7.9 7.8 8.0 7.9 8.0 7.9 8.0 7.9 DO Median 8.9 9.5 8.1 8.8 9.6 9.4 8.7 8.9 9.4 8.8 10th Percentile 7.4 8.2 7.2 7.7 8.0 8.2 8.3 6.5 8.0 6.4 90th Percentile 10.4 10.6 11.0 10.4 10.9 10.1 9.8 11.2 10.0 10.1 Turbidity Median 1.9 2.9 16.1 9.5 2.8 2.4 2.7 1.8 2.2 1.2 10th Percentile 1.3 1.5 1.5 1.9 1.5 1.7 1.2 1.2 1.6 0.7 90th Percentile 53.3 33.1 47.2 49.7 15.1 42.8 75.6 3.4 20.7 2.1

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 76 Appendix D Biota

D.1 Condition of instream and riparian habitat The lower reaches of the Glenelg River are classified as a “Heritage River” and lie within the Lower Glenelg National Park. As a consequence of being in the National Park, riparian and instream habitats relatively intact. Upstream of the National Park, however, the Glenelg River catchment has been extensively cleared for dryland agriculture. Mitchell et al. (1996) indicates that despite extensive clearing for agriculture in the mid to upper reaches of the river, riparian vegetation shows continuous or discontinuous cover on both banks. Nevertheless, riparian vegetation is restricted to the banktop fringe and is influenced by adjacent landuse.

D.2 Fish, decapod crustacea and molluscs The native freshwater fauna (fish, decapod crustacea and bivalve mollusc) of the Glenelg River system represent a diverse assemblage with high conservation significance. Twenty species of native freshwater fish and 26 species of estuarine species have been recorded from the Glenelg River system (DNRE 2000c) (Table 6-3). Eight species have conservation significance and of these, five species are protected through their listing on the Victorian Flora and Fauna Guarantee Act 1988. Of these, four species are protected through their listing on the (ANZECC 2000) List of Threatened Australian Vertebrate Fauna. Of the twenty species of native freshwater fish, seven are known to migrate between freshwater and estuarine/marine habitats at some stage in their life cycle (Koehn 1990, O'Connor 1998) (Table 6-3). Seven species of decapod crustacea and at least three species of bivalve mollusc have also been recorded (Table 6-3). Of these, the Glenelg freshwater mussel (Hyridella glenelgensis) and the western swamp cray (Gramastacus insolitus) are suspected of being rare, with restricted distributions and low abundances (Tarmo Raadik pers comm). Consequently, these species may in the near future be rated as highly threatened fauna in Victoria (Tarmo Raadik pers comm).

D.2.1 Fish The distribution of native freshwater fish recorded from the Glenelg River system is discussed below. Flow and habitat related issues that may be impacting on the fish fauna of the Glenelg River are discussed in section 6.7.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 77 Dwarf galaxias have been recorded in the upper Glenelg River upstream of Balmoral to the headwaters, including Rocklands Reservoir and its tributaries (DNRE 2000c). This species has also been recorded near Dartmoor in Scott Creek, a tributary of the lower Glenelg River and from the upper Crawford River, upper Wannon River and various other tributaries and wetlands (DNRE 2000c). The Glenelg River basin contains some of the best dwarf galaxias populations in Victoria (Tarmo Raadik pers comm). Dwarf galaxias are classified as lower risk-near threatened (DNRE 2000b) and vulnerable (ANZECC 2000), and protected through their listing on the Victorian Flora and Fauna Guarantee Act 1988. Dwarf galaxias typically inhabit swamps and billabongs and occasionally streams (Humphries 1986, Koster 1997, McDowall 1996b). The species is considered prone to threats including habitat degradation caused by swamp drainage (SAC 1991b).

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 78 n Table 6-3: Conservation status of fish, decapod crustacea and bivalve mollusc species recorded in the Glenelg River Catchment. Scientific Name Common Name Status Scientific Name Common Name Status 1 Native Migratory Native Estuarine Anguilla australis Short-finned eel C Atherinasoma Small-mouthed Galaxias truttaceus Spotted galaxias microstoma hardyhead Galaxias maculatus Common galaxias C Acanthopagrus butcheri Black bream Geotria australis Pouched lamprey C Afurcagobius tamarensis Tamar river goby Mordacia mordax Short-headed lamprey C Aldrichetta forsteri Yellow-eye mullet Prototroctes maraena Australian grayling C Ammotretis rostratus Longsnouted flounder Pseudaphritis urvilli Tupong V, L, v Arenigobius bifrenatus Bridled goby Native Non-Migratory Argyrosomus Mulloway Edelia obscura Yarra pygmy perch LN, L, v hololepidotus Gadopsis marmoratus River blackfish upper D Arripis georgianus Tommy rough upper Wannon Wannon form Arripis truttaceus West. Aust. salmon Gadopsis marmoratus River blackfish C Chelidonichthyes kumu Red Gurnard Galaxias olidus lower Mountain galaxias D Dactylophora nigricans Dusky morwong Glenelg (lower Glenelg form) Engraulis australis Australian anchovy Galaxias olidus Mountain galaxias C Girella tricuspidata Luderick Galaxiella pusilla Dwarf galaxias LN, L, v Hyporhampus Southern sea garfish Hypseleotris klunzingeri Western carp gudgeon C melanochir Macquaria ambigua Golden perch V, Macquaria colonorum Estuary perch Macquaria australasica Macquarie perch End, L Mugil cephalus Sea mullet Nannoperca australis Southern pygmy perch C Nemadactylus douglasii Blue morwong Nannoperca variegata Variegated pygmy V, L, v Nesogobius hinsbyi Orange spotted goby Perch Platycephalus bassensis Sand flathead Philypnodon grandiceps Flat-headed gudgeon C Pomatomus saltatrix Tailor Retropinna semoni Australian smelt C Pseudogobius olorum Swan river goby Freshwater Exotic Rhomboselea taparina Greenback flounder Carassius auratus Goldfish Ruboralaga Red rock cod Gambusia holbrooki Eastern gambusia ergastulorum Oncorhynchus mykiss Rainbow trout Sillaginodes punctata King George whiting Oncorhynchus Chinook salmon Tasmanogobius lasti Lagoon goby tshawytscha Tetractenos glaber Smooth toadfish Salmo trutta Brown trout Tinca tinca Tench Perca fluviatilis Redfin

Decapod crustacea Bivalve mollusca Cherax destructor Yabby Common Hyridella glenelgensis Glenelg freshwater Rare2 Euastacus bispinosis Glenelg spiny cray Common mussel Geocherax falcata Western cray Common Velesunio ambiguus Freshwater mussel Common Gramastacus insolitus Western swamp cray Common Corbicula australis Pea mussel Common Paratya australiensis Freshwater shrimp Common Engaeus lyelli Upland burrowing cray Common Engaeus strictifrons Portland burrowing Common Cray 1Abbreviations denote conservation status as; LN, lower risk-near threatened; C, common; End, endangered; V, vulnerable D, data deficient (DNRE 2000b); L, listed; E, endangered; N, nominated (Flora and Fauna Guarantee Act); v, vulnerable (ANZECC 2000) 2suspected to be endangered (Tarmo Raadik pers comm)

Variegated pygmy perch are endemic to the Glenelg River system and have been recorded in the mid reaches of the Glenelg River between Harrow to Strathdownie (DNRE 2000c). This species has also been recorded in the lower Crawford, Stokes and Wannon rivers, Grange Burn and various tributaries. Little is known about the species distribution upstream of Harrow. The species typically inhabits flowing water, and is associated with dense aquatic vegetation and substrates of gravel, cobble or boulder in the absence of silt (Koehn 1990, Kuiter 1996). Variegated pygmy perch are classified as vulnerable (ANZECC 2000, DNRE 2000b) and protected through their listing on the Victorian Flora and Fauna Guarantee Act 1988. The species is considered prone to threats including habitat degradation caused by stock access, alteration to temperature regimes and sediment input to streams (DCNR 1993).

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 79 Yarra pygmy perch have been recorded in the Glenelg River from Balmoral to Casterton (DNRE 2000c). The species is widespread with the Glenelg River catchment having been recorded in the Crawford River, Wannon River and tributaries, and various wetlands. It is likely that the Glenelg River catchment supports some of the best Yarra pygmy perch population in Victoria (Tarmo Raadik pers comm). The species typically inhabits flowing water and well-vegetated streams (Koehn 1990, Kuiter 1996). Yarra pygmy perch are classified as lower risk-near threatened (DNRE 2000b) and vulnerable (ANZECC 2000), and protected through their listing on the Victorian Flora and Fauna Guarantee Act 1988. The species is considered prone to threats including habitat modification, in particular the removal of riparian and instream vegetation (SAC 1991a).

Golden perch and Macquarie perch are not indigenous to the Glenelg catchment. Nevertheless, both species are of conservation significance. The conservation status of golden perch in Victoria is described as vulnerable (DNRE 2000b). Similarly, Macquarie perch are considered endangered in Victoria (DNRE 2000b) and are protected through their listing on the Victorian Flora and Fauna Guarantee Act 1988. Golden perch have been recorded from Ess Lagoon off the Glenelg River, Wannon River near Wannon Falls and Hamilton Lake (DNRE 2000c). The species typically inhabits slow-flowing rivers and floodplain lakes (Harris 1996) and has undergone a decline in number across its range, potentially due to habitat degradation, construction of dams and weirs and alteration of the natural hydrology (flow and temperature regimes) (Harris 1996). Macquarie perch have been recorded from Ess Lagoon and the Wannon River between Wannon Falls and Nigretta Falls (DNRE 2000c). This species typically inhabits riverine and lake habitats (Harris 1996) and has undergone a decline in number across its range, potentially due to siltation of stream beds, construction of dams and weirs and alteration of the natural hydrology (flow and temperature regimes) (Koehn 1990).

Australian grayling was recorded in the Glenelg River in 1896, however no recent records exist (DNRE 2000c). Australian grayling are classified as vulnerable (ANZECC 2000, DNRE 2000b) and protected through their listing on the Victorian Flora and Fauna Guarantee Act 1988. The species typically inhabits streams with a moderate flow and gravel substrate (McDowall 1996c). Australian grayling has become extinct in a major part of its range attributable to the construction of dams and weirs restricting migration, and the alteration of natural stream flow and temperature regimes (SAC 1991c).

River blackfish have been recorded throughout most of the Glenelg River and tributary streams (DNRE 2000c). River blackfish populations in the upper Wannon River are spatially isolated from other Victorian populations and as such may be genetically distinct and of conservation significance. This particular population has been recognised and its conservation status classified as "data deficient" (DNRE 2000b). River blackfish inhabit a variety of stream types, preferably with abundant cover such as snags and vegetation (Koehn 1990). The species is considered susceptible to increased sediment loads in streams and degradation of natural riparian vegetation (Doeg 1994).

Mountain galaxias have been recorded in the Glenelg River between Harrow and Rocklands Reservoir and most tributary streams throughout the catchment (DNRE 2000c). Mountain galaxias populations in the lower Glenelg River are spatially isolated from other Victorian populations and as such may be genetically distinct and

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 80 of conservation significance. This particular population has been recognised and its conservation status classified as "data deficient" (DNRE 2000b). Mountain galaxias typically inhabits small streams at higher elevations where water temperatures remain cool in summer (McDowall 1996b).

Southern pygmy perch have been recorded in the Glenelg River between Balmoral and Chetwynd most other parts of the catchment in tributary streams and wetlands (DNRE 2000c). Southern pygmy perch typically inhabit small, slow flowing streams and wetlands with abundant aquatic vegetation (Kuiter 1996).

Common galaxias have been recorded throughout most of the Glenelg River and tributary streams (DNRE 2000c). This species typically inhabits slow flowing or still waters (Koehn 1990). A land-locked population of this species is present in Rocklands Reservoir (Tarmo Raadik pers comm).

Australian smelt have been recorded in the mid reaches of the Glenelg River near Dergholm and Casterton as well as from the river mouth (DNRE 2000c). This species has also been recorded in the Wando, Stokes and Wannon rivers and various tributaries. Australian smelt typically inhabit slow flowing or still waters (McDowall 1996a).

Short-finned eel have been recorded in the Glenelg River near Balmoral, Chetwynd and Casterton, and from the river mouth (DNRE 2000c). This species has also been recorded in the Crawford and Wannon rivers and Grange Burn. Short-finned eel occupy a variety of habitats including rivers, creeks and wetlands (Beumer 1996).

Tupong have been recorded in the Glenelg River from Harrow downstream to the river mouth (DNRE 2000c). This species has also been recorded in the Wando, Wannon and Crawford rivers and tributaries. Tupong typically inhabit the beds of slow flowing streams, and often remain partly buried among rocks and logs (Andrews 1996).

Flat-headed gudgeon have been recorded in the Glenelg River from Balmoral downstream to the river mouth (DNRE 2000c). This species has also been recorded in Rocklands Reservoir, the Wannon and Crawford rivers and various tributary streams. Flat-headed gudgeon typically inhabit slow flowing or still waters, usually amongst weed or mud bottoms (Larson 1996).

Spotted galaxias have been recorded from a number of tributaries of the lower Glenelg River (DNRE 2000c). This species typically inhabits the lower reaches of streams, occupying pool habitats amongst logs, boulders or overhanging banks (McDowall 1996b).

Western carp gudgeon have only been recorded in the Wannon River and its tributaries, there are no records for the Glenelg River (DNRE 2000c). This species typically inhabits slow flowing streams amongst aquatic vegetation (Koehn 1990) and may have been introduced into the Glenelg River catchment via stockings of other native fish species (e.g. golden perch).

Short-headed lamprey has been recorded in the Glenelg River near Harrow and Chetwynd (DNRE 2000c). This species has also been recorded in the lower Wannon, Stokes and Crawford rivers and Moleside Creek.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 81 Pouched lamprey are only known from the Glenelg River near Casterton (1888) and from an unspecified location in 1928. No recent records exist (DNRE 2000c). Pouched lamprey are a cryptic species that are rarely caught throughout their range in Victoria (Tarmo Raadik pers comm).

D.2.2 Decapod Crustacea Distribution information for decapod crustaceans in the Glenelg River catchment is limited. Available records primarily represent by-catch of netting and electrofishing surveys conducted for fish species. Nevertheless, some information is available on the distribution of Glenelg spiny crayfish (Euastacus bispinosus).

In Victoria, Glenelg spiny crayfish are restricted to the Glenelg River basin. Mitchell et al. (1996) suggest that they may once have been distributed throughout the basin but their range may now be restricted by habitat degradation. The distribution of the species is now associated with large areas of remnant bush and may be particularly reliant on intact riparian vegetation (Mitchell et al. 1996). Crayfish are also likely to require deep pools as drought refuges and abundant woody debris for cover. Siltation, flow regulation, desnagging and riparian vegetation clearing in the Glenelg River basin have led to the loss of important habitat attributes, particularly in the mid to upper catchment.

Salinisation may have also had an impact on Glenelg spiny crayfish. Crayfish moult frequently when small, but by 50 mm OCL moulting is restricted to once a year between January to May. At this time water quality in the modified upper river is poor with elevated temperature and salinity, and reduced oxygen levels. When a crayfish moults its ability to osmoregulate is reduced, consequently high salinities may reduce growth or survival (Mitchell 1996).

Western swamp cray in the Glenelg River basin are restricted in distribution and have only been collected in low abundances (Zeidler and Adams 1990). The species is most often associated with wetlands, permanent swamps, creeks and drains.

D.2.3 Macroinvertebrates (EPA 1999) recorded a total of 86 families of macroinvertebrates from a total of 61 survey sites throughout the Glenelg River catchment (Table 6-4). Studies by (Mitchell 1996) and (EPA 1999) report a dominance of insects (such as beetles, mayflies and true bugs) in the macroinvertebrate community, as is commonly the case in fresh waters (EPA 1999). Based on the macroinvertebrate communities present, the health of sites in the Glenelg River were assessed as good to excellent in both pools and shallow habitats based on ratings presented on OCE (1988). Increased community complexity and abundance of macroinvertebrates was reported at sites with macrophytes and organic debris (Mitchell 1996).

In contrast, a study undertaken as part of the National River Health Strategy (Schreiber et al. 1998) the Glenelg River Catchment was described as highly degraded, based on several measures of stream health including the assessment of instream habitats and macroinvertebrate populations. One particular analysis of water health (Chessman 1995), which uses macroinvertebrate populations and the relative pollution sensitivities of individual taxa, identified the possible presence of mild to moderate pollution at most of the sites sampled. Only four sites were described as

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 82 n Table 6-4: Macroinvertebrate communities in the mid to upper Glenelg River (Mitchell 1996). Group % of taxa Crustacea 8 Mollusca 9 Insecta Hemiptera 12 Trichoptera 11 Diptera 10 Hymenoptera 6 Ephemeroptera 2 Coleoptera 19 Odonata 4 Lepidoptera 4 Mecoptera 1 Annelida Oligochaeta 2 Hirudinea 3 Arachnida 9 Platyhelminthes 1 having clean water quality status (Schreiber et al. 1998). Conflicting results, however, were obtained using AUSRIVAS, another tool for assessing the condition of streams.

AUSRIVAS is a biotic index that relates the macroinvertebrate taxa occurring at individual sites to species that are expected to occur at those sites. The list of expected taxa is based on the macroinvertebrate populations present at reference sites located in pristine reaches of stream. Of 53 sites used in the AUSRIVAS model, 26 sites had the expected macroinvertebrate fauna and were therefore described as good condition (Schreiber et al. 1998). However due to reference sites being non-pristine these results were confounded and might be misleading. Signal scores for these 26 sites however showed the macroinvertebrate fauna at 20 sites was reasonably tolerant and therefore indicated that mild to moderate pollution may exist. Twenty-six sites had AUSRIVAS scores that indicated mild disturbance. A further five sites had AUSRIVAS scores indicating moderate to severe impact on water and/or habitat condition

In general, most sites in the Glenelg River Catchment are considered to have poor or very poor aquatic habitats. SIGNAL scores indicate mild or moderate pollution at most sites. The degraded condition of Glenelg River catchment reflects the high level of erosion and clearing that has occurred. Sites considered to have good habitat quality and water quality were located in or near National Parks.

D.3 Birds There have been 271 species of bird recorded in the Glenelg River of which 50 species have conservation significance either in Victoria or nationally (DNRE 2000a, DNRE 2000b). Of the threatened species, 20 are reliant directly upon the instream environment for their survival (Table 6-5). No information, however, is available on the impacts of altered flow regimes on these species.

D.4 Amphibians and reptiles One species of threatened amphibian, the warty bell frog (Litoria raniformis), has been recorded from the Glenelg catchment from near Balmoral in 1963, Dartmoor in 1972, Dergholm in 1979, and from Rocklands Reservoir in 1981. Nevertheless, no recent records exist (DNRE 2000a). The conservation status of this species is

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 83 vulnerable (DNRE 2000b). Two species of threatened reptile, the swamp skink (Egernia coventryi) and tree goanna (Varanus varius), have been recorded from the Glenelg catchment (DNRE 2000a). Only two records of the swamp skink exist in the catchment, namely, near Nelson (1980) and the Crawford River (1988). No recent records exist and the conservation status of this species is vulnerable (DNRE 2000b). Only one record of the tree goanna exists in the catchment (Rocklands Reservoir - 1981) and its conservation status is data deficient (DNRE 2000b). Although the tree goanna does not directly depend on the riparian environment, such areas often provide the only remaining habitat.

D.5 Other vertebrates Other vertebrates present in the catchment and known to depend directly on the instream environment for food and shelter include the platypus (Ornithorhynchus anatinus) and water rat (Hydromys chrysogaster) (DNRE 2000a). Platypus have been recorded in the Glenelg River near Casterton and Dartmoor and in the vicinity of Fulham Hole. The species has also been recorded in the Wannon River near Coleraine and Hamilton, Mackinnon Creek and Grange Burn (unpublished database Australian Platypus Conservancy; Melanie Tranter pers comm). There is no documented distribution information for the water rat.

The effect of altered flow regimes on these species is undocumented. Nevertheless, it may be assumed that deep holes would provide refuge areas during periods of low flow. Consequently, sedimentation and salinisation may restrict the availability of this important habitat. Further more, artificially reduced flows during low flow periods may lead to a direct loss of habitat (through a lack of water depth) and the potential loss of runs between pools. This may have implications for the movement of platypus between pools and foraging behaviour, thus restricting platypus to regions of poor water quality.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 84 D.6 Instream and riparian flora Of the 63 threatened flora species that occur in the Glenelg River catchment, 15 of them rely directly on the instream environment or temporary inundation of off channel areas for their survival (DNRE, 2000; Dale Tonkinson DNRE pers. comm., 2000) (Table 6-5). Gilgai Blown-grass. (Agrostis aemula var setifolia), wetland blown- grass (Agrostis avenacea var. perennis) and Gilgai blown-grass (Agrostis billardierei var. filifolia) all occur in seasonally wet areas. River swamp wallaby-grass (Amphibromus fluitans), lax twig-sedge (Baumea laxa), swamp flax-lily (Dianella callicarpa), showy lobelia (Lobelia beaugleholei), violet bladderwort (Utricularia violacea) and swamp fireweed (Senecio psilocarpus) all occur in swampy and waterlogged soils. Bog gum (Eucalyptus kitsoniana) and dark mignonette-orchid (Microtis orbicularis) occur in coastal swamps, metallic sun-orchid (Thelymitra epipactoides) occurs in heathy swamps and swamp greenhood (Pterostylis tenuissima) occurs in tea-tree swamps. Lime fern (Pneumatopteris pennigera) is a riparian species that grows on limestone and rough eyebright (Euphrasia scabra) is a riparian species that has become extinct in the area except for one locality at Wandovale (Dale

n Table 6-5: Threatened birds dependent on instream and wetland habitats of the Glenelg River. Scientific Name Common Name Status 1 Anas rhynchotis Australasian shoveler V Ardea alba Great egret E, L Aythya australis Hardhead V Biziura lobata Musk duck V Botaurus poiciloptilus Australasian bittern E, N Burhinus grallarius Bush stone-curlew E, L Cereopsis novaehollandiae Cape barren goose V Chlidonias hybridus Whiskered tern LN Egretta garzetta Little egret CE, L Grus rubicunda Brolga V, L Haliaeetus leucogaster White-bellied sea eagle E, L Ixobrychus minutus Australasian bittern E, N Numenius madagascariensis Eastern curlew LN Nycticorax caledonicus Nankeen night heron V Oxyura australis Blue-billed duck V, N Phalacrocorax varius Pied cormorant V Platalea regia Royal spoonbill V Porzana pusilla Baillon’s crake V, N Rallus pectoralis Lewin’s rail E, N Sterna caspia Caspian tern V Stictonetta naevosa Freckled duck E, L 1Abbreviations denote conservation status as E, endangered; V, vulnerable; LN, lower risk-near threatened; D, data deficient (DNRE 2000b); L, listed; N, nominated (Victorian Flora and Fauna Guarantee Act 1988).

Tonkinson, DNRE, pers. comm., 2000).

Thirty species of aquatic and semi-terrestrial macrophyte have been recorded in the mid to upper reaches of the Glenelg River (Mitchell 1996). Species richness within sites ranged from 7-11. Emergent aquatic macrophyte species were dominant and represent between 67 and 100% of species present at sites surveyed.

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 85 Low flows and sediment deposition in the mid to upper Glenelg River have been found to be facilitating the excessive growth of Typha and Phragmites australis in the river channel (Mitchell 1996). This consequently impedes flows and leads to further sediment deposition and reduction in habitat complexity.

Mitchell et al. (1996) also noted that a conspicuous feature of macrophyte communities was the absence of submerged aquatic macrophyte species in downstream sites. It was suggested that salinities in pools at the downstream sites may be sufficiently high to affect the growth of submerged macrophytes.

D.7 The Glenelg Heritage River and Lower Glenelg National Park. The lower section of the Glenelg River, from Nelson on the coast to Dartmoor, is designated a “Heritage River” under the Heritage Rivers ACT 1992 (DNRE 1997). The Heritage River corridor covers an area of approximately 3020 Ha and is about 50 m wide for most of its length. The lower section of the Heritage River flows through the Lower Glenelg National Park. The Heritage River corridor provides an important habitat link particularly between inland woodlands and the coast for species reliant on riparian habitats. This habitat corridor is well protected within the National park although public land water frontages are degraded at Nelson and below Dartmoor (DNRE 1997).

There are several key values associated with the heritage section of the lower Glenelg River. These include; q 13 rare or threatened flora species are known to occur in the Heritage River corridor although many of these are only known from local knowledge (DNRE 1997). Rare Bog Gum, The Lime Fern are two examples. Two species are listed under the Flora and Fauna Guarantee Act 1988 (FFG): the leafy greenhood and the limestone spider-orchid. q 23 significant fauna species in the Heritage River Corridor. A further five significant fish species. Of these species 11 are listed in the FFG ACT 1988 (DNRE 1997). q the Lower Glenelg karst area – an area of limestone between Keegan's Bend and Nelson which is of state significance (LCC 1991), q rare and threatened fauna (see section 6.2-6.6), q remnant River Red Gum community south of Dartmoor (DNRE 1997), q Moleside Creek ( a tributary of the Glenelg River) contains numerous species of fern, q a diverse fish fauna in both freshwater and estuarine sections, q high landscape values including extensive caves that provide habitat for several significant species of bat and the Glenelg River estuary which represents the only estuary in Victoria developed in a framework of dune calcarenite ridges (Bird 1977) ,

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 86 q numerous recreational values – fishing, boating, camping, walking (DNRE 1997).

Key management directions have been proposed for the lower sections of the Glenelg River that will maintain and enhance existing values. These include; q restore habitat links along the River to the coast, q improve environmental water values of the River, particularly the estuary, and develop trigger levels for opening of the river mouth, q undertake research and monitoring of significant fish species and environments, monitor sand and silt effects on the River including the sand slug upstream the heritage River corridor (DNRE 1997).

WC01432:R04_MJS_GLENELG_FINAL.DOC Final PAGE 87