Assessment of Salinity Management Options for Kyeamba Creek, New South Wales: DATA ANALYSIS and GROUNDWATER MODELLING

KNOWLEDGE Landscapes & Industries Glen R.Walker Richard G.Cresswell, Warrick R.Dawes,Greg K.Summerell, DATA ANALYSIS ANDGROUNDWATER MODELLING Creek, NewSouthWales: management options forKyeamba Assessment ofsalinity

Assessment of salinity management options for Kyeamba Creek, New South Wales: DATA ANALYSIS AND GROUNDWATER MODELLING

Richard G. Cresswell, Warrick R. Dawes, Greg K. Summerell, Glen R. Walker Authors: Richard G. Cresswell 1, Warrick R. Dawes 2, Greg K. Summerell 3,4,5, Glen R. Walker 6, 7

1. Bureau of Rural Sciences, Canberra, ACT 2. CSIRO Land and Water, Canberra, ACT 3. Centre for Natural Resources, NSW Department of Land and Water Conservation, Wagga Wagga, NSW 4. CRC for Catchment Hydrology, Canberra, ACT 5. University of Melbourne, Melbourne, Victoria 6. CSIRO Land and Water, Adelaide, SA 7. Rural Solutions SA, Adelaide, SA

CSIRO Land and Water Technical Report 26/03 CRC for Catchment Hydrology Technical Report 03/9 MDBC Publication 12/03

Published by: Murray-Darling Basin Commission

Level 5, 15 Moore Street Canberra ACT 2600

Telephone: (02) 6279 0100 from overseas + 61 2 6279 0100 Facsimile: (02) 6248 8053 from overseas + 61 2 6248 8053 Email: [email protected] Internet: http://www.mdbc.gov.au

ISBN: 1 876 830 52 2

Cover photo: Arthur Mostead Margin photo: Mat Gilfedder

This work is copyright. Photographs, cover artwork and logos are not to be reproduced, copied or stored by any process without the written permission of the copyright holders or owners. All commercial rights are reserved and no part of this publication covered by copyright may be reproduced, copied or stored in any form or by any means for the purpose of acquiring profit or generating monies through commercially exploiting (including but not limited to sales) any part of or the whole of this publication except with the written permission of the copyright holders.

However, the copyright holders permit any person to reproduce or copy the text and other graphics in this publication or any part of it for the purposes of research, scientific advancement, academic discussion, record-keeping, free distribution, educational use or for any other public use or benefit provided that any such reproduction or copy (in part or in whole) acknowledges the permission of the copyright holders and its source (‘Assessment of salinity management options for Kyeamba Creek, New South Wales: Data analysis and groundwater modelling’) is clearly acknowledged.

To the extent permitted by law, the copyright holders (including its employees and consultants) exclude all liability to any person for any consequences, including but not limited to all losses, damages, costs, expenses and any other compensation, arising directly or indirectly from using this report (in part or in whole) and any information or material contained in it.

The contents of this publication do not purport to represent the position of the Murray-Darling Basin Commission or CSIRO in any way and are presented for the purpose of informing and stimulating discussion for improved management of Basin's natural resources. Acknowledgements

This report represents a synthesis of information garnered from a wide spectrum of work performed on a relatively small catchment within the Murrumbidgee River system. This report places Kyeamba Creek into the context of Catchment Characterisation, with emphasis on the salinity perspective as outlined by Coram (1998) and Coram et al. (2000). The Catchment Characterisation Framework was made possible through the concerted efforts over many years of local and regional hydrogeologists who first developed and populated the concept from a dryland salinity perspective. Many of these are mentioned in Coram (1998), and have contributed to various aspects of this and other work over a period of years.

This report draws on the vast store of knowledge held in the archives and minds of people within the institutions listed with the authors. In particular, this report draws on work carried out for local Landcare and communities by Department of Land and Water Conservation staff, particularly Don Woolley, Darice Pepper, Frank Harvey and Hugh Jones, and by former Australian Geological Survey Organisation (now Geoscience Australia) staff, particularly Jim Kellett (now with Bureau of Rural Sciences) and Phil Bierworth.

This work was funded under the Murray-Darling Basin Commission’s Strategic Investigations and Education Program, Grant Number D9004: ‘Catchment characterisation and hydrogeological modelling to assess salinisation risk and effectiveness of management options’.

This report has benefited immensely from reviews from Ray Evans and Jai Vaze, and from numerous discussions with other members of the Catchment Characterisation project. Editorial support from Mat Gilfedder and Pauline English (CSIRO Land and Water) is gratefully appreciated.

i CATCHMENT CHARACTERISATION, KYEAMBA CREEK CASE STUDY Executive summary

Introduction Kyeamba Creek is represented as Intermediate and Local Flow Systems in Kyeamba Creek catchment, located within fractured rock aquifers (Palaeozoic the uplands of the Lachlan Fold Belt of fractured rock in the Coram et al. 2000 south-eastern Australia, comprises an classification). Suggested management intermediate-scale fractured rock aquifer with options for this type of flow system include overlying alluvial fill in drainage lines and revegetation/reafforestation of upper depressions. This study of the catchments using perennial pastures, hydrogeological factors influencing salinity in native pasture, and native trees, possibly the Kyeamba catchment was undertaken to: with some groundwater pumping applications (Coram et al. 2000). These • describe the physical setting and systems commonly have only a small condition of the Kyeamba Creek proportion of land area actually salinised, catchment and aquifer system less than two percent, but can be a major • examine various data interpretations source of salt via saline discharge to on the conceptual model of flow streams and larger river systems. processes for recharge and discharge Discharge typically occurs at breaks of • model the historical and present-day slope, and directly through sediments hydraulic head trends along valley floors. • model possible future salinity mitigation scenarios for the aquifer.

Site Description

Within the Murray-Darling Basin, Kyeamba Creek is a third-order catchment feeding the Murrumbidgee River. The catchment is located south-east of the city of Wagga Wagga in central New South Wales. The major surface drainage features are Kyeamba, Livingstone and O’Briens Creeks. Average annual rainfall is 650 mm, with a gradient decreasing from south to north from the granite highlands to the alluvial plains at the confluence with the Murrumbidgee. Land Location of ‘Intermediate and Local Flow Systems in use is dominantly cattle grazing, with fractured rock aquifers’ in the Murray-Darling Basin. subordinate cropping, horticulture and, in the higher country, sheep grazing. In the Kyeamba catchment, salinity is manifest as small, scattered patches of Groundwater Flow System salinised land and locally shallow, saline The catchment, covering an area of groundwater. Increasing stream salinity and approximately 600 km2, lies within an salt export to the Murrumbidgee River are intermediate-scale fractured rock aquifer. the main salinity issues in the area. These Overlying valley fill alluvium represents a salinisation outcomes are particularly shallow secondary, local-scale aquifer promoted in the lower landscape by a lack system. The catchment thus contains a of hydraulic gradient, as well as by dual aquifer system: upper local-scale restrictions in the aquifer caused by sub- alluvial aquifers and an intermediate-scale, surface highs, typically of granite. deeper fractured rock aquifer. ii CATCHMENT CHARACTERISATION, KYEAMBA CREEK CASE STUDY the outbreak of surface salinity Current estimations suggest that the is the overlying local alluvial system. The quantity of salt being exported from the system is highly responsive to revegetation / Kyeamba catchment is the second largest reafforestation management options. Further, per unit area in the Murrumbidgee region. sub-surface salt stores can be mobilised Notwithstanding, the total salt contribution upward by the hydraulic heads in the from Kyeamba of 20,000 t/yr constitutes fractured rock, and become available for only a maximum of five per cent of the delivery to the stream network from the salt load measured in the Murrumbidgee alluvial fill. River passing Wagga Wagga. Salt loads are highly variable, however, ranging from While broad-scale reafforestation may 200,000 to 700,000 tonnes per year alleviate salinity concerns in the long term, passing Wagga Wagga. the fact that groundwater levels are high and stable, i.e. in dynamic equilibrium, Groundwater modelling means that the system may continue as a viable agricultural region for the foreseeable The FLOWTUBE model, a simple future. groundwater model based on Darcy’s Law, Kyeamba Creek catchment may be typical was used to simulate the variation in of many within the Lachlan Fold Belt groundwater on the groundwater flow country of central New South Wales and system. The model resolves for changes in northern Victoria. Extension of findings to hydraulic head induced by recharge and other catchments is feasible, following discharge fluxes, and lateral transfers in the detailed evaluation of local hydrogeological direction of flow, and is represented by a factors. Rainfall considerations are hydraulic head transect along the aquifer. paramount in the findings; higher rainfall For the Kyeamba catchment, parameters regions will likely require more drastic for intermediate-scale, fractured bedrock interventions and must be evaluated within and local-scale, alluvial aquifer systems the context of local information. were modelled. Outputs from the simulation of past and Conclusions present heads emphasise the dominance of the upper alluvial aquifer system • Groundwater levels, and hence generating shallow water tables and salinity concerns in the catchment, salinised areas, fed by salt pushed upward are highly dependent on climatic, by heads in the fractured rock aquifer. The i.e. rainfall, conditions. modelling generated a rapid response of water levels to modelled recharge • Targeted perennial plantings would reduction scenarios. This finding reinforces allow direct management of current on-ground mitigation measures in individual saline areas, while longer- the catchment in the form of targeted term and more extensive revegetation, but questions the applicability reforestation would be required to of widespread reforestation. generally lower groundwater levels. • Increased use of pumped aquifers Portability of conceptual near the confluence with the model, tools and results Murrumbidgee River may negate the need for groundwater level reduction, This case study emphasises the need for though the effects are likely to be good local knowledge and understanding restricted to the region within ten of the groundwater system. While classified kilometres of the confluence with the as an intermediate fractured rock aquifer Murrumbidgee due to bedrock system, the dominant system controlling constrictions up valley.

iii CATCHMENT CHARACTERISATION, KYEAMBA CREEK CASE STUDY • Extension of the findings to similar catchments along the west of the Great Dividing Range of New South Wales are encouraged, but not to the higher rainfall regions.

Recommendations

• Continued monitoring of the catchment water levels, stream flow and salinities to enable confident evaluation of the response of the system to anticipated land use changes. Continue local strategy of localised management of saline outbreaks.

• Compare catchment behaviour to other catchments of a similar type to gain confidence in the catchment classification process.

• Extend the study to encompass the adjoining Tarcutta Creek catchment.

iv CATCHMENT CHARACTERISATION, KYEAMBA CREEK CASE STUDY Table of contents

Acknowledgements i

Executive summary ii

1. Introduction 1

2. Physical setting 3 2.1 Location and catchment description 3 2.2 Salinity issues 5 2.3 Salinity in the context of catchment surface morphology 5 2.4 Rainfall considerations 7

3. Conceptual hydrogeological model 8 3.1 Surface water 8 3.2 Groundwater trends 8 3.3 Groundwater salinity 11 3.4 Stream salinity 12

4. Groundwater modelling using FLOWTUBE 14 4.1 Numerical model 14 4.2 Special considerations 14 4.3 Composite aquifer model 19 4.4 Alluvial aquifer model 19 4.5 FLOWTUBE modelling summary 21 4.6 Future tree planting 21 4.7 CATSALT modelling 24

5. Discussion and conclusions 26

6. Future directions 27

References 28

v CATCHMENT CHARACTERISATION, KYEAMBA CREEK CASE STUDY vi CATCHMENT CHARACTERISATION, KYEAMBA CREEK CASE STUDY 1. Introduction

Dryland salinity is a major issue in Australia, intermediate-scale fractured rock aquifer and clear understanding is required to guide system comprised of the Kyeamba and appropriate investment toward management Tarcutta catchments. The major surface of the problem. Understanding catchment drainage features, however, are Kyeamba scale processes is crucial towards identifying Creek and O’Briens Creek, lying on an management options, although in most alluvial plain, whose sediments contain a Australian catchments the existing series of shallow alluvial aquifers. This knowledge-base and data collection is too shallow system is readily delineated from limited to provide this. aerial photographs and can be considered as a local scale flow system (Figure 1). The combination of physical factors governing dryland salinity varies across Australia. The diversity in geology, landscape development, the quantities of salt stored in the landscape, and climatic characteristics all contribute. Similarly, the viable options for managing dryland salinity, and the timescale of groundwater and salinity responses vary from region to region. The variation of groundwater-driven dryland salinity, according to these first-order factors, has been described for the whole of Australia through the National Land and Water Resources Audit (NLWRA) project ‘Australian Groundwater Flow Systems Influencing Dryland Salinity’ (Coram 1998, Coram et al. 2000).

Within the NLWRA four dryland salinity case studies have been published. Each describes the conceptual understanding of a specific Figure 1. Extent of the alluvial system in Kyeamba groundwater flow system; models the prior Valley, deduced from bore logs and break of slope determinations using the model FLAG (courtesy T. and current situation in terms of land use and Dowling, CSIRO Land and Water). Bores indicated by groundwater recharge and examines dots; indicative thickness of alluvials shown by darkening colours. possible future options for recharge reduction through revegetation and groundwater Land salinisation in Kyeamba Creek is very pumping (Stauffacher et al. 2000, Short et al. localised, with small patches scattered 2000, Baker et al. 2001, Hekmeijer et al. across the central and northern areas of the 2001). catchment. Some shallow saline Four further catchments have now been groundwaters do exist, and in the past have studied as part of this Catchment hampered some efforts to establish trees, Characterisation project—the South Loddon such as at Turkey Flat. The more serious plains and Axe Creek in Victoria, and environmental problem in the catchment, Kyeamba Creek and Brymaroo in NSW. however, is that of variable, and often high, The aim of such case studies is to describe stream salinity. This catchment produces a the different groundwater flow systems (GFS) large amount of salt per unit area 2 identified by Coram (1998) and Coram et al. (38.5 tonnes/year/km —Beale et al. 2000) (2000). compared with other catchments in the immediate area of the mid-Murrumbidgee, The Kyeamba Creek catchment is located which average 18.2 tonnes/year/km2 south-east of the city of Wagga Wagga in (12 catchments) and across New South central New South Wales. It lies within an Wales (14.7 tonnes/year/km2 for 63 third-

1 CATCHMENT CHARACTERISATION, KYEAMBA CREEK CASE STUDY order catchments evaluated by NSW DLWC—Beale et al., 2000).

Kyeamba Creek catchment is also the focus of stream flow and salinity measurement analysis (Harvey & Jones, 2003) and surface water and salt balance modelling (Tuteja et al. 2002), work carried out by the NSW Department of Land and Water Conservation, and several aspects of these studies will be touched upon within this report.

The main aims of this case study report are:

• to describe the physical setting and condition of the Kyeamba Creek catchment and aquifer system • to examine various data interpretations on the conceptual model of flow processes for recharge and discharge • model the historical and current head trends with FLOWTUBE • model future tree-planting scenarios for the aquifer system.

2 CATCHMENT CHARACTERISATION, KYEAMBA CREEK CASE STUDY 2. Physical setting

2.1 Location and catchment description

Kyeamba Creek is a third-order tributary feeding the Murrumbidgee River just to the south-east of Wagga Wagga, New South Wales (Figure 2).

The Kyeamba Creek catchment (Figure 3) covers 602 km2, with the sharp relief of the hills to the south contributing to a total land surface of 755 km2. The catchment has an average (over the last 50 years) rainfall of 650 Figure 2. Location of Kyeamba Creek Catchment, NSW. mm/year, exhibiting a south to north gradient from 800 mm/year over the granite hills to the south, decreasing to 600 mm/year at its confluence with the Murrumbidgee River to the north. The main creek is structurally controlled, and follows the general north north-west (NNW) trend of the underlying fractured Palaeozoic sediments.

Kyeamba Creek has been characterised, by Coram et al. (2000), as a local flow system in fractured rock. The catchment is comprised of Silurian age granite intrusions, emplaced into older Ordovician turbidite sediments. The valley floor is now covered with extensive alluvial sediments, the variable thickness of which being governed by bedrock topography. Lineaments observed in airborne magnetic survey data indicate NE trending Figure 3. Locality and topographic map for Kyeamba dykes and faults, which are responsible for Creek catchment . offsets in the creek’s general NNW trend. A major tributary to the west, O’Briens Creek, a hydrogeologic connection between the two follows one of these offset trends. catchments beneath the alluvial plains Constrictions in the catchment occur where (Figure 4b). The fractured bedrock aquifer is subsurface features cross-cut the creek’s probably more extensive then the surface NNW trend. One particularly prominent catchment and, thus, is representative of an obstruction is caused by a basement high in intermediate flow system in the classification the vicinity of Ladysmith, 10 km from the scheme of Coram et al. (2000). confluence with the Murrumbidgee River. Kyeamba Creek is therefore regarded as a The regional geology shows a ring of granite tandem aquifer system comprising a shallow, hills that encompass both the Kyeamba local flow system that is defined by the valley catchment and the easterly adjacent Tarcutta floor alluvial sediments, and an underlying Creek catchment. Topography between the deeper intermediate system in fractured two catchments becomes quite subdued to rocks, the extent of which is defined by the north (Figure 4a) and consideration of surrounding granites. potentiometric contours for groundwaters in the fractured Palaeozoic sediments (J. Kellett, pers. comm. 2001) suggests

3 CATCHMENT CHARACTERISATION, KYEAMBA CREEK CASE STUDY Figure 4a. Regional DEM, showing the stream network of Kyeamba Creek.

Figure 4b. Regional DEM superimposed by the potentiometric surface for the main fractured rock aquifer.

4 CATCHMENT CHARACTERISATION, KYEAMBA CREEK CASE STUDY 2.2 Salinity issues

The New South Wales Department of Land and Water Conservation (DLWC) Salinity Audit (Beale et al. 2000) determined that Kyeamba Creek released the second highest proportion of salt per unit area of the catchments feeding the Murrumbidgee River (after the much smaller Adelong Creek— 48.4 tonnes/year/km2 from 155 km2). An average annual salt-load (1975-1995) of 20,400 tonnes flows past Ladysmith, 12 km from the confluence with the Murrumbidgee River (Beale et al. 2000). As a comparison, the slightly larger (758 km2) Billabung Creek catchment contributes only 6600 tonnes/year to the Murrumbidgee River. Tarcutta Creek, at two and a half times the area (1660 km2), contributes a similar 26,200 tonnes/year. Kyeamba Creek only contributes approximately five percent of the salt in the Figure 5. Mapped surface salinity outbreaks in Kyeamba Valley, 1995. Murrumbidgee River passing Wagga Wagga, but is currently exporting roughly ten times the amount of salt being brought in via rainfall.

While land salinisation is not a major problem in the catchment, constituting less than one percent of the area (Figure 5), catchments with similar output/input ratios, such as Boorowa and Yass, are facing major land salinisation problems. Salinity in the Kyeamba catchment, however, is not directly related to soil type, and only weakly to slope. The dominant influence is the structural control of the valley by underlying geologic features. Specifically, surface ridges (identified in Figure 6) belie the presence of sub-surface barriers to the groundwater movement towards the Murrumbidgee. These impediments to flow cause pooling of groundwater and local rises in water table. Figure 6. Kyeamba geology and structural controls. 2.3 Salinity in the Context Two main functions are employed: of Catchment Surface Morphology (i) Each position is interrogated to determine how much of the Surface morphology for the catchment has surrounding landscape lies been modelled using the digital elevation monotonically above that point modelling tool FLAG (Fuzzy Logic Applied to (termed UPNESS). Geographical Information Systems) of Roberts et al. (1997) and Dowling (2000). (ii) What is the relative position in the This model evaluates each location for its landscape of any point relative to all position in the landscape relative to all other the points around it (LOWNESS)? locations in the study catchment area.

5 CATCHMENT CHARACTERISATION, KYEAMBA CREEK CASE STUDY The former is used to determine the potential a position has as a regional, or catchment, depocentre. That is, if water were to be introduced uniformly across the landscape (e.g. rainfall), how much would potentially cross any given point? This gives a good indication of areas prone to waterlogging. The latter function assesses each point as a local depocentre. That is, if water were to cross that point, how likely is it that the water would stay there, or lose sufficient energy to drop its suspended load? This gives a good indication of sediment accumulation zones.

FLAG UPNESS analysis for Kyeamba Creek is shown in Figure 7. Stream channels are depicted and the trajectories of the creeks are outlined. Comparison to other catchments in the mid-Murrumbidgee region (Figure 8) shows similarities and differences Figure 7. FLAG UPNESS index for Kyeamba Creek between Kyeamba Creek and other Catchment scaled between maximum (1) and catchments. Interestingly, the main Kyeamba minimum (0) values for this catchment alone. Creek is similar to the majority of catchments, including the neighbouring While salinity outbreaks show some Tarcutta Creek, while O’Briens Creek is correspondence to high FLAG index, this similar to Billabung, Muttama and Tumut appears to be a second order effect, catchments, but not the adjoining Tarcutta confirming the primary effect of structural Creek catchment, or many of the others. control on water tables and hence salinity.

Figure 8. FLAG UPNESS index for the Mid-Murrumbidgee region. Scales are normalised to minimum and maximum values or each entire study region.

6 CATCHMENT CHARACTERISATION, KYEAMBA CREEK CASE STUDY 2.4 Rainfall Considerations

1400 Annual rainfall records for Humula (within the Humula averages adjoining Tarcutta catchment, but close to 1200 Wagga Wagga the watershed at the southern end of averages Kyeamba Creek) and Wagga Wagga (as a 1000 proxy for the northern end of Kyeamba Creek) are shown in Figure 9. 800 791 mm/a mm 600 Rainfall records from 1900 to 1950 are 598 mm/a 581 mm/a sparse, but suggest a lower average monthly 480 mm/a 400 rainfall than for the latter half of this century.

From the daily records at Humula, we can 200 deduce that rainfall events have decreased in intensity (from a median of 4.3 to 3.8 0 mm/day), but increased in frequency (from Jan-00 Jan-10 Jan-20 Jan-30 Jan-40 Jan-50 Jan-60 Jan-70 Jan-80 Jan-90 Jan-00 year 86 to 107 days/year). Average yearly rainfall for the last 50 years is 20-30% higher than Figure 9. Rainfall records for Humula (near the that for the first half of the last century. As we Kyeamba source) and Wagga Wagga (near Kyeamba Creek’s outlet to the Murrumbidgee) for the past have an incomplete record for these stations, 100 years. the continuous record from Cootamundra (80 km NE of Kyeamba) has also been evaluated. Cumulative deviation from the 300 mean rainfall is plotted for monthly data in 0 Figure 10, and shows a drying trend prior to 250 1945, followed by a predominantly wetting cumulative deviation from the mean (for 100 years) trend to 2000. The past 50 years have been -1000 200 wetter than the previous 50 years (lower curve in Figure 10—ten year moving -2000 150 average), and a distinction between relatively 10 year moving average 1 year moving average wet and relatively dry periods can be made, -3000 100 highlighted as spikes in the lower curve

(1 year moving average) in Figure 10. averages (mm monthly rainfall) -4000 50 cumulative deviation (mm monthly rainfall)

-5000 0 Jan-00 Jan-10 Jan-20 Jan-30 Jan-40 Jan-50 Jan-60 Jan-70 Jan-80 Jan-90 Jan-00

Figure 10. Rainfall records for Cootamundra (80 km NE of Kyeamba) for the past 100 years. Upper graph shows cumulative monthly deviation from the mean. Steep slopes indicate dry (down) and wet (up) periods. The lower graph summarises this into yearly and decadal information (but based on monthly figures). Wet periods are denoted by spikes in the annual trace above the 10 year average, while dry periods are below the line. Overall, the last 50 years have been wetter than the previous 50, although the frequency of flood periods has been similar.

7 CATCHMENT CHARACTERISATION, KYEAMBA CREEK CASE STUDY 3. Conceptual Hydrogeological Model

3.1 Surface water conductivity values) are low, but the variable salinities of the tributaries indicate the sub- Recently, stream surveys have been carried catchments that hold potential salt stores. out with an aim of discerning the regions of Flow rates are generally low. The tributaries importance regarding salt store to O’Briens Creek, however, have medium remobilisation. Using FLAG analysis to help flow and contribute most salt to the main prioritise creeks for surveying, stream channel. salinities and approximate flow rates have been collected for a number of rain events. Kyeamba Creek represents a system in A typical high flow event is illustrated in disequilibrium. Alternating erosional and Figure 11. Salinities throughout (indicated by depositional stretches result from changes in flow regime, probably caused by vegetation clearing, heavy grazing and drainage of reed-swamps mainly during the late 19th Century, but continuing through to Salt Load the present in a similar manner to that >20 t/day Kyeamba Creek Coolarado Creek recorded for Tarcutta (Page & Carden 11-20 t/day @ Monavale Flow: N/A 6-10 t/day Flow: 23 mgl/day EC: EC: 920 uS/cm 4-5 t/day Salt: Load 13.54 t/day 1998). Knowledge of erosion and 2-3 t/day 0- 1 t/day Kyeamba Creek Wrights Gully Creek depositional environments, which can be Flow: 23 mgl/day Flow: N/A No flow EC: 881 uS/cm EC: Salt: Load 12.9 t/day indicated by FLAG analysis, helps delimit

Clares lane Kyeamba Creek areas that may now be releasing salt Flow: 0.115 mgl/day Flow: 23 mgl/day EC: 154 uS/cm EC: 875 uS/cm Salt: Load 0.012 t/day Salt: Load 12.8 t/day stored in soils into stream channels, and Clares lane Flow: 0.0014 mgl/day EC: can indicate which sub-catchments would 199 uS/cm Yirrkala Creek Salt: Load 0.0001 t/day Flow: N/A EC: benefit from revegetation, and those that The Willows Flow: N/A Tywong EC: Flow: N/A EC: would not. Spring Creek Tooles Creek Flow: 0.216 mgl/day Flow: 0.346 mgl/day EC: 108 uS/cm EC: 2.4 mS/cm Salt: Load 0.015 t/day Salt: Load 0.53 t/day

Obriens Creek Obriens Creek Kyeamba Creek Flow: Flow: 1.04 mgl/day 10 mgl/day Flow: 20 mgl/day 3.2 Groundwater trends EC: EC: 155.9 uS/cm 1230 uS/cm EC: 635 uS/cm Salt Salt : Load 0.1 t/day : Load 7.8728 t/day Salt: Load 8.128 t/day Kyeamba Creek Flow: 19.5 mgl/day Obriens Creek EC: 478 uS/cm Mapping in the 1990s revealed a sympathy Flow: 10.8 mgl/day Salt: Load 5.96 t/day EC: 800 uS/cm Salt: Load 5.534 t/day Book Book Creek between the Kyeamba and Tarcutta Flow: 0.005 mgl/day Pinnacle Creek EC: 478 uS/cm Salt Flow: 0.144 mgl/day : Load 0.001 t/day groundwater systems, particularly in the EC: 863 uS/cm Salt : Load 0.079 t/day Kyeamba Creek Flow: 18 mgl/day lower reach aquifers. Water tables shallow EC: 529 uS/cm Salt: Load 6..09 t/day towards the Murrumbidgee, then deepen Livingstone Creek Near Tantanoola Flow: 0.864 mgl/day Flow:N/A EC: 1506 uS/cm EC: Salt: Load 0.08 t/day within the Murrumbidgee alluvial sediments

Near Ginninderra (J. Kellett, pers. comm. 2001). Pooling of Flow:N/A Near Hume Hwy Flow:N/A EC: groundwater upstream of Ladysmith corresponds to rising water levels seen in the alluvial aquifers of Tarcutta to the east, in the area known locally as Corienbob Catchment. Preparedbythe Wagga Wagga Research Centre,Centre for NaturalResources, Wagga Wagga. Groundwater flow is from the south-east, from the ranges around Tumbarumba, and Figure 11. A snap shot of the salinities and relative flows of the creeks of Kyeamba Catchment after the heads NW towards the Murrumbidgee storm of 16/8/2000. Streams are coloured based on through the Palaeozoic sediments, their relative salinities, and are overlaid on an artificially shaded digital elevation model. Note that constrained by the surrounding granites. salinities are not exactly contemporaneous, as EC Groundwater in the fractured rock aquifers varies throughout a storm as salt loads and water volumes vary. Measurements were taken over the cross the surface catchment divide between course of 6 hours following the rain event. Flow rates Tarcutta and Kyeamba Creeks, while surficial are estimates based on the rate of filling of a 9L waters follow the routes outlined by the bucket, and are scaled to represent to potential contribution to the gauging station at Ladysmith. alluvial sediments.

8 CATCHMENT CHARACTERISATION, KYEAMBA CREEK CASE STUDY -5

10 SWL (m) 15 GW025383 GW030032

20 GW030033 GW030034 GW030286 GW030351 25 GW030355 GW030385 Tarcuttta GW030386 30 Jan-70 Jan-75 Jan-80 Jan-85 Jan-90 Jan-95 Jan-00 date

Figure 12. Hydrographs for nested piezometer sites in the Kyeamba Valley and NW Tarcutta.

-5

15 SWL (m)

35 Jan-70 Jan-75 Jan-80 Jan-85 Jan-90 Jan-95 Jan-00

Figure 13. Hydrographs for bores in the Kyeamba catchment (includes two bores from the adjoining Tarcutta catchment).

Most domestic and farm supplies are derived piezometers giving similar heads (Figure 12) from the unconfined aquifers in the alluvial despite the differing conductivity and sediments of the lower reaches. These aquifers, storativity of the respective aquifers. and those sourced in the weathered bedrock horizon immediately below, provide good Groundwater levels in the alluvials across the quality water, but variable yield. Transmissivity Kyeamba catchment have remained steady and storativity are quite variable. While over the last 30 years (Figure 13), in contrast transmissivity can be high (>100 m2/day), to predictions based on two-point analysis of storativity is generally low (<0.01). In general, groundwater levels by DLWC, shown in the alluvial aquifers have higher hydraulic Figure 14—note, however, the lack of conductivity (K) (8x10-10 m/day) than the topographic constraint on this model weathered horizons (2x10-10 m/day). The (D. Woolley, written comm. 2001). Variability unweathered fractured bedrock exhibits variable in the standing water levels suggests an K (2 – 6x10-10m/day), but often very high association with rainfall events, reflecting the transmissivity (>100 m2/day), presumably due largely unconfined nature of the system and to fracture networks. Fractured bedrock rapid equilibration between different aquifers. is comprised of Ordovician shales and siltstones in the lower reaches, and granites at higher elevations. Connectivity between the alluvials & fractured rocks is good, with nested

9 CATCHMENT CHARACTERISATION, KYEAMBA CREEK CASE STUDY Interestingly, while rainfall records (Figures 9 and 10) indicate the 1990s to be wetter than average, the bore records in Kyeamba indicate a generally downward, or drying, trend.

Using water levels recorded at the time, a bore was drilled, compared to the level measured during a bore survey in 1990, we can determine average rates of rise for bore waters across the region. These show a wide range of rates, from slightly falling to rising at nearly 2 m/year (Figure 15). The fastest rates of rise appear to be for bores sampling the fractured Palaeozoic aquifers installed since 1950, with lowest rates consistently from the alluvial aquifers. It should be apparent from examination of rainfall and bore records that the time of measurement is a critical factor determining this rate, particularly for two- point analysis.

By estimating the specific yield—a function of porosity and connectivity—for the differing rock types, and assuming no drainage, or removal of excess water from the system, we can estimate the minimum amount of water required for this rise. Assuming specific yield values of one, three and five percent for the fractured rocks, weathered granite bedrock and alluvials respectively, gives a more restricted range up to 20 mm/year, with an average of 7 mm/year excess recharge to the system (Figure 16). A Figures 14a-d. Postulated water levels for Kyeamba Creek for the years 2000, 2020, 2050 and 2100 (after complex model, CATSALT, developed by Woolley, 1996).

1.00

Alluvials Silurian granites 0.80 Ordovician sediments

0.60

0.40

0.20

average rate of water level rise (m/a) 0.00

-0.20 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 year of construction

Figure 15. Rate of water level rise for Kyeamba Creek bores.

10 CATCHMENT CHARACTERISATION, KYEAMBA CREEK CASE STUDY DLWC for water balance in the catchment gives a figure of 10 mm/year for its 20 equivalent parameter: ‘routed groundwater’ alluvials 18 Silurian granites (Tuteja et al. 2002) (Figure 17).

a) Ordovician sediments / 16 average excess water

er level (mm

3.3 Groundwater salinity t a 12

ree

Groundwater salinity varies markedly across tf 10 the catchment, with variability of up to two 8 orders of magnitude within a few kilometres 6.6 mm/a 6 in some areas (Figure 18). In general, deeper

rease in equivalen

c aquifers are slightly fresher than upper ones, In 4 but the connectivity of the system ensures 2 reasonable vertical mixing throughout. Two 0 zones of higher salinity waters (>1500 mg/L 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 year of construction TDS) coincide with deep structural anomalies, which are expressed as surface Figure 16. Equivalent increase in water level for lineations (Figure 6). These occur in bands different lithology aquifers in Kyeamba Creek. trending NE-SW, one through Ladysmith, the Murrumbidgee, however, is restricted by and a second extending SW from Turkey Flat the cross-sectional area of the discharge towards Livingstone. This latter may extend conduit and the transmissivity of the aquifers. to the NE across Tooles Creek, although Since Kyeamba Creek’s discharge zone is there are insufficient bores to be certain. We constricted by granite highs, the time surmise that pooling is occurring upstream of required to discharge any excess water these features. received from recharge will be long Kyeamba Creek experiences significant water compared to the period of water level rise during major storm events. accumulation and would require extended Recharge occurs across the entire periods of drought to maintain constant catchment. Discharge of groundwater via average water levels.

Figure 17. Cartoon illustrating the derived water balance for Kyeamba Creek, based on CATSALT modelling (after, Tuteja, et al, 2002).

11 CATCHMENT CHARACTERISATION, KYEAMBA CREEK CASE STUDY use of moderately halophytic plants may be successful. A stand of poplars that failed to survive at Turkey Flat in the 1980s, for example, have been successfully replaced by casuarinas (Woolley 1991).

A related issue is illustrated to the west of O’Briens Bridge where waterlogging with moderately saline waters has occurred due to damming of a natural flow-line to the river by the road. To the west, on the upstream side of the road, salinity is evident in poor pasture with salt bush. To the east of the road, free drainage to the creek has permitted good pasture to develop.

3.4 Stream Salinity

Stream surveys (Figure 11) delimit regions where salt in the landscape is being recycled into the surface waters. Livingstone Creek feeding into O’Briens Creek south of Mt. Flakney and Tooles Creek feeding into Kyeamba Creek at Turkey Flat are streams with known high salinities (>1000 µS/cm EC), as are streams feeding Kyeamba Creek at Ladysmith. Lower salinity streams feeding Ladysmith from the granite hills to the west are reflecting surface runoff from the granites.

Stream surveys during dry spells delimit regions where baseflow is entering the surface system. Livingstone Creek feeds into O’Briens Creek south of Mt. Flakney, and Figures 18. Postulated water levels for Kyeamba shows a progression of stream salinities Creek for the years 2000, 2020, 2050 and 2100 (after towards its confluence with the main channel Woolley, 1996). (Figure 19). A prior preferential flow is delimited by the sudden increase in salinity Current annual discharge of water from seen at location 4 in Figure 19b, marking the Kyeamba into the Murrumbidgee is about re-emergence of the old Livingstone Creek 55 GL, equivalent to 94 mm of stream flow. into O’Briens Creek. This carries the average annual salt load of 20,000 tonnes, and relates to roughly ten Harvey and Jones (2003) have analysed times the amount of salt being brought into 30 years of stream flow and salinity data the catchment via rainfall. Observed salt from four catchments in the Upper loads at Wagga Wagga over the past ten Murrumbidgee, including Kyeamba and years have varied from below 200,000 to Tarcutta Creeks. For the available data, time, over 700,000 tonnes per year, largely volume (flow) and surface run-off salinity dependent on stream flow. Reduction of the (electrical conductivity) relationships were salt load in Kyeamba, therefore, can have no examined. Specifically, a general relationship more than a five percent effect on the load exists of the form: seen at Wagga Wagga. C = a Q b The last century shows an average of 20 mm excess rainfall over annual recharge across where C is the total dissolved concentration the region. Salinities across the region are of salts (using EC as proxy), Q is the generally low, and in higher salinity areas the instantaneous flow-rate (ML/day), and a and

12 CATCHMENT CHARACTERISATION, KYEAMBA CREEK CASE STUDY 9 8 7 6 5 4 3 1 2 OBriens Creek 2000 2.5

EC (µ S/cm) )

Salt load (t/d) /d

iigtn CreekLivingstone 1600 Flow (ML/d) 2.0

(ML

S/c 1200 1.5

rFl

)

t/d EC ( 800 1.0

(

400 0.5 t

S 0 0.0 12 3 4 5 6789 Sites

Figure 19. Baseflow measurements along tributaries of O’Briens Creek. a) Survey sites are superimposed over a DEM for the region. b) EC , salt load and flow for the sites along the 9 km survey stretch (figure from Summerell, 2001).

b are constants (with b<0). This describes Jugiong catchment appeared to plateau and the generally accepted inverse relationship may be decreasing, though data become between salinity and flow, which is due more sparse after 1998, and variance in the primarily to dilution as flow increases data is less well constrained. There is no data (Gregory & Whaling 1973). For baseflow, the for Kyeamba for this period as the flow EC was found to be time dependent for station was removed from Ladysmith some sites. in 1985 and relocated upstream at Book Book. This station was relocated at The observed trends adequately discriminate Ladysmith in 1997. base (groundwater) flow from stream (overland) flow. Baseflow in Kyeamba seems Fitting the data to the power function to range between 400 and 3000 µ S/cm, and described above suggested to Harvey & Jones is evident in flows at Ladysmith up to 20 (2003) that the parameter ‘b’ is similar for all ML/day. Beyond these flow rates EC catchments, and probably represents a regional decreases, though a large number of events parameter. The parameter ‘a’, however, varies around the maximum of 400 ML/day show a between catchments, and we suggest that range of EC up the maximum observed in this represents local variations and is catchment the baseflow. Data is insufficient to determine specific. Broadly, ‘b’ relates to the slope of the causal relationship between this and the EC vs flow data, and may be related to extreme rainfall events. climatic effects and regional management responses. ‘a’ is a measure of the magnitude Comparing the more complete record of of the salinity response and may relate to flows and EC measurements taken from variations in catchment geology, Jugiong Creek to the east, Harvey & Jones geomorphology and local land use practices. (2003) observed a progressive increase in EC for any given flow is observed with time. Thus, for the same instantaneous flow rate measured through the 1970s and1980s, the EC increases by 1.7% per year.Similar trends are seen in the T arcutta andMuttama data, and by extrapolation we expect Kyeamba to show the same trend. A 1.2% increase in EC per year for Tarcutta, and 3.1% for Kyeamba up to the 1990s was observed. In the early 1990s, this trend for

13 CATCHMENT CHARACTERISATION, KYEAMBA CREEK CASE STUDY 4. Groundwater modelling using FLOWTUBE

4.1 Numerical model The two main aquifer parameters in FLOWTUBE are hydraulic conductivity and FLOWTUBE (Dawes et al. 1997, 2000, 2001) specific yield, both of which are often difficult is a simple numerical one-dimensional to measure or estimate directly in fractured groundwater flow model. It is a mass- rock environments (Freeze & Cherry 1979, balance model that solves for a change in Lapsevic et al. 1999, Love & Cook 1999). hydraulic head induced by recharge and Measurements have been taken in Kyeamba discharge fluxes, and lateral transfers in the Creek by the use of pump tests, but the direction of flow. The results of FLOWTUBE parameters ultimately remain fitted values are considered to be a hydraulic head that are representative of the Darcian flow transect along an aquifer. model at the scale of the FLOWTUBE segments. Freeze and Cherry (1979) suggest The model considers a one or two layer that in fractured rock environments simply system. In the case of a single layer the increasing the size of computational cells aquifer is assumed to be unconfined and allows the common solution methods to be having variable transmissivity dependent on applied to groundwater flow. the saturated thickness of aquifer. In the case of a two-layer system, the lower layer is The two different aquifers were modelled in assumed to contain any lateral transmission stages. First, data from the more limited of water while the upper layer contributes number of bores in the fractured rock storage capacity only. In this case the lower aquifers were combined with the more layer is usually confined or semi-confined, comprehensive data from the alluvial and how this is conceptualised controls the unconfined aquifers to give composite simulated mechanism for groundwater hydraulic properties for the system as a discharge. whole (the intermediate system). Second the alluvials were treated as a single aquifer (local 4.2 Special considerations system). The former was modelled at a coarse scale with five kilometre cells, while FLOWTUBE is ideally suited to homogenous the alluvial model used finer two kilometre uniform isotropic media, such as sand and cells. This reflected the greater confidence in gravel aquifers, and massive clay deposits the parameters available for the alluvial without preferred pathways or barriers. In the aquifers based on existing bore data. The Kyeamba Creek system there are both an alluvials included the basal leads where these alluvial aquifer consisting of porous sands and were the dominant aquifers, regardless of silts intercalated with silty clays, and a deeper whether this included the upper weathered fractured rock aquifer that controls the deeper zone or not. The distribution of modelled flow directions. For the alluvial system it is zones is shown in Figures 20 and 21. expected that FLOWTUBE will be very appropriate and well suited to simulation. In Input parameters for the two scenarios are the deeper fractured rock aquifer there are listed in Table 1a and b, and illustrated in caveats that need to be placed on parameters Figures 22 and 23. and conclusions. Unlike some environments, such as Axe Creek in Victoria (Hekmeijer & Dawes 2003), in Kyeamba Creek the dominant fracture direction and hydraulic gradients are coincident. In this case there is confidence that using estimated properties of the fractured media will be representative in a Darcian framework.

14 CATCHMENT CHARACTERISATION, KYEAMBA CREEK CASE STUDY Figure 20. Modelled cell distribution for the fractured- Figure 21. Modelled cell distribution for the alluvial rock aquifer scenario. aquifer scenario.

TABLE 1a. Input parameters for Scenario 1

GW Surf Width Thick Base Cond Length Por Idc

311 320 10,000 60 260 15 5000 0.01 2

292 300 11,500 60 240 15 5000 0.01 3

273 280 13,000 65 215 20 5000 0.02 4

254 260 11,500 70 190 25 5000 0.03 5

235 240 10,000 70 170 30 5000 0.04 9

271 280 23,000 60 220 20 5000 0.02 7

238 243 14,500 65 178 25 5000 0.03 8

220 222 7000 70 152 30 5000 0.04 9

210 211 10,000 80 131 35 5000 0.05 10

202 205 7000 80 125 40 5000 0.05 11

195 199 4500 80 119 45 5000 0.05 12

187 191 3000 80 111 50 5000 0.05 -1

Flowtube groundwater model input parameters. Each row is a segment along the flowtube. GW:Initial groundwater elevation (m); Surf: Ground surface elevation(m); Width: Aquifer width (m); Thick: Aquifer thickness (m); Base: Aquifer basement elevation (m); Cond: Hydraulic Conductivity (m/yr); Length: Length of segment (m); Por: Porosity; Idc: the segment immediately downstream (-1=end of tube)

15 CATCHMENT CHARACTERISATION, KYEAMBA CREEK CASE STUDY TABLE 1b. Input parameters for Scenario 2

GW Surf Width Thick Base Cond Length Por Idc

420 440 500 20 420 10 2000 0.01 2

404 424 750 20 404 10 2000 0.01 3

380 400 1100 20 380 10 2000 0.01 4

350 370 1650 20 350 10 2000 0.01 5

323 325 3450 20 305 10 2000 0.01 6

298 300 3100 20 280 10 2000 0.01 7

269 273 2000 20 253 10 2000 0.02 8

263 270 3450 20 250 10 2000 0.03 9

261 263 2550 20 243 10 2000 0.04 10

253 255 2200 20 235 10 2000 0.05 11

231 237 1300 20 217 10 2000 0.06 12

223 236 1300 20 216 20 2000 0.07 13

220 234 1600 20 214 20 2000 0.08 14

217 221 1100 20 201 20 2000 0.09 15

209 215 1450 20 195 20 2000 0.1 26

310 330 500 20 310 10 2000 0.01 17

290 310 2000 20 290 10 2000 0.02 18

281 301 2000 20 281 10 2000 0.03 19

265 270 4750 20 250 10 2000 0.04 20

255 260 6400 20 240 10 2000 0.05 21

245 250 6200 20 230 10 2000 0.06 22

231 240 2200 20 220 10 2000 0.07 23

225 235 2750 20 215 10 2000 0.08 24

216 226 2550 20 206 10 2000 0.09 25

209 218 3300 30 188 20 2000 0.1 26

203 212 2400 30 182 20 2000 0.1 27

202 208 1100 35 173 20 2000 0.1 28

201 206 1300 40 166 20 2000 0.1 29

200 205 1100 45 160 20 2000 0.1 30

198 202 1100 50 152 20 2000 0.1 31

188 198 1100 55 143 20 2000 0.1 32

187 194 1300 60 134 20 2000 0.1 33

183 190 3650 70 120 20 2000 0.1 34

171 179 1000 80 99 20 2000 0.1 -1 Flowtube groundwater model input parameters. Each row is a segment along the flowtube. GW:Initial groundwater elevation (m); Surf: Ground surface elevation(m); Width: Aquifer width (m); Thick: Aquifer thickness (m); Base: Aquifer basement elevation (m); Cond: Hydraulic Conductivity (m/yr); Length: Length of segment (m); Por: Porosity; Idc: the segment immediately downstream (-1=end of tube)

16 CATCHMENT CHARACTERISATION, KYEAMBA CREEK CASE STUDY 400 ground surface 350 groundwater surface base of aquifer

AHD) 300

n(m

o 250 Kyeamba Creek

t 200

Eleva 150 O’Briens Creek 100 0 102030405060 Relative distancealong creeks (km)

2.5 70 volume of aquifer conductivity (m/s) 60

2 porosity (%) si

o 50 r O’Briens Creek Po

)

3 1.5

40 ty o

ivi

lume (km 30 d

o 1 n

20 cco

Kyeamba Creek rauli 0.5 10 yd

0 0 0 1020304050607080 Relative distancealong creeks (km) 16000 9000 Widthofoutcrop (m) 14000 Thickness of aquifer (cm) 8000

7000 12000 Kyeamba Creek 6000 10000 5000

kness

dth

i 8000

w 4000 T 6000 O’Briens Creek 3000 4000 2000

2000 1000

0 0 0 1020304050607080 Relative distancealong creeks (km)

Figure 22. Parameters used for modelling the combined aquifer system.

17 CATCHMENT CHARACTERISATION, KYEAMBA CREEK CASE STUDY 450 ground surface 400 groundwater surface top of aquifer base of aquifer 350

AHD) Kyeamba Creek 300

n(m

i t 250

Eleva 200 O'Briens Creek 150

O’Briens Creek offsetfor clarity 100 0 102030405060 Relative distancealong creeks (km)

7000 9000 widthofoutcrop (m) thickness (cm) 8000 6000 7000 5000 Kyeamba Creek 6000 O'Briens Creek dth 4000 5000

kness

3000 4000 h

T 3000 2000 2000 1000 1000

0 0 01020304050607080 Relative distancealong creeks (km)

0.6 70 volume of aquifer (km3 ) conductivity (m/s) 60 0.5 ty

porosity (%) si

r 50

)

0.4 O'Briens Creek Kyeamba Creek r

40 ty o 0.3 ivi

lume (km

o 30 d

V 0.2

20 cco

0.1 rauli

10 yd

0 0 0 1020304050607080

Relative distancealong creeks (km)

Figure 23. Parameters used for modelling the alluvial aquifer system only.

18 CATCHMENT CHARACTERISATION, KYEAMBA CREEK CASE STUDY 350 350

upper Kyeamba Creek O'Briens + lower Kyeamba Creek Surface 300 Year 1900 300 Year 2000

AHD)

n(m,

o 250

250 i

n (m,

Eleva

Eleva 200 Surface 200 Year 1900 Year 2000

150 150 0 5 10 15 20 25 30 30 35 40 45 50 55 60 Distance (km) Distance (km)

Figure 24. Simulated groundwater heads within the composite Kyeamba Creek system, for (a) O’Briens and lower Kyeamba Creek, and (b) upper Kyeamba Creek, with pre-clearing recharge of 1 mm/year, and post-clearing of 20 mm/year.

4.3 Composite aquifer model Kyeamba system and Murrumbidgee system can be approximately separated just north of The coarse-scale model was dominated by Ladysmith, coincident with the major the parameters of the fractured bedrock in structural feature mentioned earlier. the upper regions and by the deep alluvials downstream. Aquifer thickness and porosity increased towards the Murrumbidgee. This 4.4 Alluvial aquifer model model reasonably recreates the observed, Using the parameters in Table 1b, Figure 25 present-day, groundwater surface along the shows the simulated results of adding a main Kyeamba Creek. It does not, however, constant 20 mm/year recharge for 100 years. indicate the high groundwater levels seen The right-hand slope is the main part of along the main western tributary, O’Briens Kyeamba Creek above the confluence with Creek. Figures 24a and 24b show the O’Briens Creek. The slope between 16 and simulated groundwater heads in the 36km is the arm of O’Briens Creek itself. composite aquifer. The black and red lines show present-day A pre-clearing recharge rate of 1 mm/year surfaces; the green represents 100 years of 1 was assumed for the native condition, while mm/year recharge; the blue line is for 20 a uniform post-clearing recharge rate of 20 mm/year added to the aquifer for a further mm/year was applied in this simulation. It is 100 years. These values represent extremes suggested by Tuteja (pers. comm. 2002) that in recharge for the catchment, and give the current recharge is distributed with rainfall upper and lower bounds to the ultimate state and soil type, at rates between 15 and 40 of the water table. Plotted in a brown dashed mm/year. The resulting catchment average line is the aquifer capacity, the amount of rate is slightly higher than that used here. water the aquifer can carry, with the parameters as given. This clearly shows why Many of the heads prior to widespread we have such a variable pattern of clearing are shown near the base of the groundwater heads—the thickness varies by aquifer, indicating that elevated water tables an order of magnitude between nodes, and were not present under native vegetation. In is up to 49 m thick in places. This sawtooth the simulations, significant filling is generated post clearing, and particularly occurs in the 450 30000

Surface vicinity of the confluence of O’Briens and 400 25000 Initial

Kyeamba Creek, and in the narrow neck 100yr @ 1mm (m Capacity Aquifer 100yr @ 20mm 350 20000 between that confluence and the Aq. Capacity Murrumbidgee River. 300 15000 3 /day)

Elevation (m AHD) 250 10000 In general, FLOWTUBE delimits the confluences of the major tributaries as 200 5000 regions of elevated water tables. These 150 0 0 10203040506070 regions also correspond to thinning aquifers Distance (km) over basement highs, and thicker sequences Figure 25. Results from FLOWTUBE for the alluvial of alluvial material immediately upstream. The model.

19 CATCHMENT CHARACTERISATION, KYEAMBA CREEK CASE STUDY is partly a relic of sporadic bore information 450 1.2 Surface on a system with complex interconnectivity Initial 400 100yr@1mm 1.0 and we suspect that the actual stream might 100yr @ 20mm Aq. Capacity (10 Capacity Aquifer give a more monotonically decreasing trend, 350 0.8

not a saw-tooth. 300 0.6 6 m 3 Elevation (m AHD) /day) The alluvial model gives a poor description of 250 0.4

present-day levels along the main creek, but 200 0.2 highlights areas along O’Briens Creek that 150 0.0 correspond to present-day near-surface 0 10203040506070 Distance (km) levels. This result is important both for understanding the catchment and the Figure 26. Results from FLOWTUBE for the ‘smoothed’ alluvial model. processes within it that drive dryland salinisation. If only one of the two model 4.4.1.i Monotonically-increasing conductivity, descriptions adequately showed all mapped thickness and porosity downstream areas of high water levels, then the other would be redundant. But since both models The conductivity, thickness and porosity are have features the other does not show, this modified so that they all increase as we has important implications for remediation. move downstream along the FLOWTUBE. This reflects a general coarsening of deposits towards the mouth of the main creek. The 4.4.1 Alternative alluvial models major factor in capacity is now the width and Noting that deficiencies in bore information slope of the FLOWTUBE, but for the scenario may mean that the modelled profile may not depicted in the following graph (Figure 26) accurately reflect the true profile, with bores the slope component has been removed. rarely sited along a flow path, not well 4.4.1.ii Use the current groundwater spread, not well spaced, nor representative gradients to model transmissivity of the entire alluvial body, we can postulate a more smoothly varying profiles using some The next modelling approach is to fit basic principles of hydrogeology. We can transmissivity to apparent current modify parameters such that we achieve a groundwater gradients and see what evolves; monotonic increase in those parameters that this will produce an independent assessment we might expect to increase downstream, or of porosity. The most obvious features occur we can take the postulated groundwater where we require very large conductivity gradient and fit appropriate parameters to fit values to maintain drainage through the that gradient. Specifically, in the former case aquifer. Those areas are likely to be where we assume an increase in hydraulic shallow water levels are and where future conductivity, aquifer thickness and porosity discharge will occur. From this, we can as we move towards the confluence with the model heads using fitted transmissivity, as Murrumbidgee. In the latter case, illustrated in Figures 27a and 27b. transmissivity is varied to conform with the modelled groundwater gradient towards the Groundwater levels reach the surface: at the mouth of the creek. confluence of the main creeks; upslope in

450 450

Surface Surface 400 400 Current Current 100yr @ 1mm 100yr @ 1mm 350 350 100yr @ 20mm 100yr @ 20mm

300 300 Confluence of Turkey Flat O'Briens + Pilliga

Confluence of Elevat on (m AHD)

Elevation (m AHD) 250 250 O'Briens + Kyeamba

200 200

150 150 36 42 48 54 60 66 72 0 6 12 18 24 30 36 Distance (km) Distance (km)

Figure 27. Modelled heads for (a) O’Briens Creek and (b) Kyeamba Creek.

20 CATCHMENT CHARACTERISATION, KYEAMBA CREEK CASE STUDY Figures 28. Modelled regions of elevated water table according to FLOWTUBE for (a) the fractured-rock, and (b) alluvial aquifer scenarios. Red areas are within 1m of the surface, and yellow areas are within 2 m.

O’Briens Creek where several streams come through an artificial construct, and does not together; up-gradient in Kyeamba Creek at explicitly describe salt movement. Turkey Flat; and further up where Tooles Creek enters from the east. Because of the In general, FLOWTUBE delimits the reverse engineering, modelled and ‘current’ confluences of the major tributaries as heads now match more closely, and we regions of elevated water tables (Figures 28a appear to be pin-pointing the major areas of and 28b). These regions also correspond to shallow water tables. Some of the fitted thinning aquifers over basement highs, and hydraulic conductivity values, however, may thicker sequences of alluvial material not be physically realistic for the aquifer occurring immediately upstream. The material. Kyeamba system and Murrumbidgee system can be approximately separated just north of Ladysmith, coincident with the major 4.5 FLOWTUBE modelling structural feature mentioned above. summary

The coarse-scale model was dominated by 4.6 Future tree planting the parameters of the fractured bedrock in In the late 1990s, regional reafforestation was the upper regions and by the deep alluvials considered as an option for salinity mitigation. downstream. Aquifer thickness and porosity To investigate this, we examined a tree planting increased towards the Murrumbidgee. This scenario, and its impact on recharge & discharge model reasonably recreates the observed, within the Kyeamba Creek catchment. A land present-day, groundwater surface along the capability analysis of Kyeamba Creek has indicated main Kyeamba Creek (Figure 24a and 24b). lonly small areas in the highest rainfall parts of the It does not, however, indicate the high catchment are most suitable for commercial ... groundwater levels seen along the main tributary, O’Briens Creek. The alluvial model gives a poorer description of present day levels along the main creek, but highlights areas along O’Briens Creek that correspond to present day near-surface levels (Figure 25). It should be emphasised that FLOWTUBE models groundwater movement

21 CATCHMENT CHARACTERISATION, KYEAMBA CREEK CASE STUDY tree planting, while the bulk of the catchment corresponds to the area of Class 3 softwood is economically marginal for both soft and in the O’Briens Creek area and extends hard woods. Figures 29a and 29b show the laterally to the topographic catchment divide result of GIS analysis of land capability for on both the eastern and western sides. The commercial planting (NSW Forests & NSW tree belt was assumed to reduce recharge DLWC 2001), with ratings from 1 (most from the current rate to zero in a five-year favourable) to 6 (no return), for softwood and start-up period, then was allowed to remain hardwood, respectively. Kyeamba Creek is at zero for a further 15 years of simulation. slightly more suitable for softwood plantations, which have enhanced The time course of head changes is not productivity in higher rainfall areas found in shown for the starting period up until the the southern parts of the catchment. present, but only for the next 20 years, and only in the O’Briens Creek section A FLOWTUBE simulation was run with a (Figure 30). Heads in this arm of the composite alluvial and fractured rock aquifer catchment responded favourably to the set-up, and distributed annual recharge recharge reduction, for both the five-year ranging from 40 mm in the south to 20 mm recharge reduction section and the 15 years in the north. Aquifer parameters are given in of simulation thereafter. The effect is still quite Table 2. For simplicity, a recharge reduction localised however, with no effect on heads zone (e.g. produced by introduction of a further downstream than 25 km from the swathe of trees) was introduced across the catchment outlet. central 13% of the catchment. This roughly

Figure 29. Land capability mapping of suitability for plantation of (a) softwood and (b) hardwood, where Class 1 is most suitable for commercial returns, and 6 is not suitable for forestry. No area of Class 1 was mapped; it was assumed that these areas would already be forested.

22 CATCHMENT CHARACTERISATION, KYEAMBA CREEK CASE STUDY TABLE 2. Input parameters for combined fractured and alluvial aquifers in O’Briens and Kyeamba creeks

O'Briens Creek section

GW Surf Width THK Base K Length Por Idc

270 284.77 2900 20 264 5 1000 0.02 2

250 263.98 7050 20 243 5 2000 0.02 3

239 252.97 10800 20 232 5 2000 0.03 4

234 238.98 8750 20 218 5 2000 0.03 5

229 231.73 5750 20 211 5 2000 0.04 6

224 226.54 4650 20 206 5 2000 0.04 19

Kyeamba Creek section

350 395.17 5500 50 335 3 2000 0.01 8

325 353.87 9500 50 293 3 2000 0.01 9

300 316.55 10500 55 256 3 2000 0.01 10

280 296.20 11250 55 236 2.5 2000 0.02 11

265 280.85 12000 60 220 2.5 2000 0.02 12

256 268.53 12700 60 208 2 2000 0.02 13

251 260.25 12000 65 195 2 2000 0.03 14

246 251.68 11300 65 186 2 2000 0.03 15

241 245.01 10600 65 180 2 2000 0.03 16

235 237.76 9900 70 167 2 2000 0.04 17

228 230.89 9200 70 160 2.5 2000 0.04 18

222 224.01 8400 70 154 2.5 2000 0.04 19

217 219.34 12400 75 144 2 2000 0.05 20

joint section to Murrumbidgee

212 214.05 11,000 75 139 5 2000 0.05 21

208 210.15 10,300 75 135 5 2000 0.05 22

203 205.88 9600 80 125 5 2000 0.05 23

198 201.00 8950 80 121 5 2000 0.05 24

193 199.09 8250 80 119 5 2000 0.05 25

188 194.16 7550 80 114 5 2000 0.05 26

184 189.66 6900 80 109 5 2000 0.05 27

180 182.81 6200 80 102 5 2000 0.05 28

177 179.98 5500 80 99 5 1000 0.05 29

175 177.71 5150 80 97 5 -1 0.05 -1

23 CATCHMENT CHARACTERISATION, KYEAMBA CREEK CASE STUDY A localisation of effectiveness was also found catchment (see Figure 30) demonstrated in the main Kyeamba Creek arm of the that very localised management is required. simulation. In this area there was no Recharge must locally be reduced to a level difference in head distribution in the such that the bottlenecks created by the discharge areas, but a lesser amount of bedrock topography can still transmit all the discharge occurred due to zero recharge groundwater. The major problem with the assumed under this zone. In the upper parts alluvial system, from a management of the recharge area heads did drop by as perspective, is that upstream of a much as one centimetre per year, but this constriction the amount of discharge is effect is unlikely to continue into the future, approximately equal to the amount of and produce the desired level of water level recharge. A 50% recharge reduction, that is control expected of such a large area of assumed to be possible from better afforestation. management alone, is unlikely to change the location of the current discharge areas,

350 but will reduce the volume of discharge with

Surface feedbacks to the stream salt load into the Year 2000 300 future. The local nature of the flow promises Trees Established, 2005 Year 2020 to show changes in water levels in the

250 short-term, e.g. less than 20 years. Greater recharge reductions will require massive Elevation (m AHD)

200 land use changes with serious socio- economic implications.

150 0 5 10 15 20 25 30 Distance (km) 4.7 CATSALT modelling Figure 30. Modelled heads in O’Briens Creek following the establishment of plantation trees over The CATSALT model has been developed five years, then an additional 15 years of zero within the NSW DLWC (Tuteja et al. 2002). recharge in their immediate vicinity. CATSALT simulates water flow and stream salinities for medium sized catchments from It has been common practice to simulate a 500 to 2000 km2 under current conditions. general reduction in recharge of 50% and Its three main components are: 90% in similar work for the NLWRA (Short et al. 2000, Stauffacher et al. 2000, Baker et al. • rainfall-runoff water balance model 2001, Hekmeijer et al. 2001). The former • salt mobilisation and wash-off reduction is assumed to be possible using component only changes to cropping and grazing practice, while the latter usually requires • Fourier Transform estimator for in- extensive land use change to trees and stream salt exported at the catchment deep-rooted perennial plants. The capacity of outlet. the aquifer towards the Murrumbidgee River The water balance component is a lumped varies between 2.2 and 5.5 mm/year over conceptual model for which there are nine the range of aquifer parameterisations used parameters (five for water balance, and four for in this report. This represents a total variation routing) that are fitted to a time series of of only a factor of 2.5, which is probably observed stream flow data with a commensurate with the level of confidence in corresponding sequence of daily rainfall and the individual values that generate this result, evaporation. The five water balance i.e. aquifer width, thickness, conductivity and parameters relate to a crop factor, a run-off hydraulic gradient. In terms of the recharge coefficient, the infiltration capacity, the soil estimated across the catchment, this is a moisture storage in root zone and an factor of between four and 20 less than what evaporation function. Since these parameters is entering the system. This has serious relate to physical factors, it is feasible to implication for broad-scale recharge estimate how these parameters, once fitted, reduction strategies. may change under certain conditions. For example, whole catchment rainfall run-off The simulation with vegetation belts and a relationships (for details, see Zhang et al. 2001) reduction to zero recharge over 13% of the

24 CATCHMENT CHARACTERISATION, KYEAMBA CREEK CASE STUDY between forest cover and long-term water yield • average annual rainfall 683 mm can be used to help recalibrate runoff • routed groundwater run-off 10 mm parameters for an afforestation scenario. The four routing parameters simulate a stream • surface run-off comprising saturated response for the groundwater and shallow flow through flow and saturation excess run- components to a rainfall event. off with no infiltration run-off 84 mm • actual evapotranspiration 600 mm. The salt balance is achieved through calibration with stream salinity data and Some detailed water balance studies at the process modelling. Three parameters are nearby Wagga Wagga research station were fitted. The first is the fraction of base flow compared with the SMAR modelling results. that is groundwater, i.e. ratio of base flow to The water balance model HYDRUS-2D was groundwater salinity. The other two used to interpret the very detailed field parameters control an adsorption isotherm measurements. This suggested that of the 84 relating soil salt storage and salinity of run- mm run-off, 27 to 37 mm occurs through off. Effectively, the salinity of the shallow flow saturated throughflow and 47 to 57 mm (quick flow) processes is calibrated to the through shallow subsurface flow. From the stream data. This is not an unreasonable salt balance analysis, the fraction of baseflow assumption for larger flow events if the salt that was directly sourced from groundwater discharge is almost linear with respect to is around seven percent. For comparison, the stream discharge, as occurs in many of the ratio of salt load in the stream flow relative to streams. The adsorption isotherm then that entering in rainfall is approximately 9:1. allows the aggregation of salt loads from various parts of the catchment according to their soil salt content. Those areas with higher salt content produce higher salinity flows and contribute a higher fraction of the salinity at the catchment outlet.

Whilst most gauging stations have good records of flow, the same is not necessarily true for stream salinity. Frequently, grab samples are taken every two to six weeks. To obtain estimates of salt balances, interpolation is required between these sampling times. Such interpolation requires correlation with flow and time from the last large event. The Fourier Transform stochastic model used in CATSALT is a relatively systematic and objective method for doing this, and can provide error estimates.

Daily stream flow was recorded in Kyeamba Creek at a gauging station at Ladysmith from 1975 to 1987, after which the gauging station was moved upstream to Book Book. Discrete electrical conductivity samples at Ladysmith were available from 1993 to 1997, with a total of 117 samples. The model calibration suggested that processes relating to evapotranspiration, soil moisture storage and saturation excess run-off in response to climate variability are the most important factors in determining run-off. This led to the following estimates for the water balance of Kyeamba Creek (see also Figure 17):

25 CATCHMENT CHARACTERISATION, KYEAMBA CREEK CASE STUDY 5. Discussion and conclusions

The Kyeamba Creek catchment covers an have consistently indicated the dominance in area of 602 km2 in central New South Wales, the surface system of an alluvial aquifer south of the city of Wagga Wagga. Salinity in within the main creek channels as the the catchment is expressed as a scattering delivery mechanism for salt to the stream. of local areas of surface soil salinity, localised Local regions are defined by variable depth shallow and saline groundwater tables, and a to the bedrock topography, and each must high stream salt load relative to the be managed on a case-by-case basis. The catchment area. This behaviour is consistent deeper and more extensive fractured rock with the expectations of Coram et al. (2000) aquifer still shows high hydraulic heads for this type of catchment. across large areas and can deliver stored salt to the surface alluvial zone. Areas of shallow water levels extrapolated from two-point bore water level rises suggest Simulations of past and present head trends that approximately two-thirds of the support the bore hydrograph data, and the catchment could suffer from shallow water concept of a catchment in dynamic levels by the Year 2100. Bore hydrographs equilibrium. Future tree-planting scenarios, and groundwater modelling, however, based on current plans for plantation forestry, indicate that water levels have remained high show a quick response of the Kyeamba and stable for up to 25 years, and that a Creek water levels, and reinforce the dynamic equilibrium may exist. Salt load data localised nature of near-surface flows and for Kyeamba Creek and other catchments in thus the management implications. the region indicate that stream EC appears Successful plantings of trees and perennials to have stabilised. within the catchment to date encourage more widespread use of this strategy. Harvey and Jones (pers. comm. 2001) have described the collection and analysis of stream electrical conductivity in four catchments within the mid-Murrumbidgee, including Kyeamba Creek. The data available at Kyeamba Creek was much less than for the other catchments studied, but all catchments show similar behaviour. An important trend evident form the data is that the EC of the streams peaked in the early nineties and now appears to have stabilised. In combination with the bore hydrograph evidence and responsiveness of FLOWTUBE simulations, we might infer that catchment water levels are in a dynamic equilibrium, and the stream flow and salt load trends are following a longer-term climatic signal. Such a situation implies that the application of the CATSALT model to current data should provide a robust estimate of the catchment processes and bulk water balance terms.

Using three different interpretations of the available bore lithology and soils mapping data, the aquifers within Kyeamba Creek have been identified and modelled using the FLOWTUBE groundwater model. The results

26 CATCHMENT CHARACTERISATION, KYEAMBA CREEK CASE STUDY 6. Future directions

Further monitoring of the Kyeamba Creek catchment is required. A permanent stream flow and conductivity recording station in the northern part of the catchment around Ladysmith would help in further constraining the response of this high salt yielding catchment. In light of the anticipated tree planting in the central to upper catchment, such data collection would add greatly to our understanding of this catchment. Periodic monitoring of individual local flow cells with saline outbreaks would also assist fine-tuning management of these areas. Continuing improvements to modelling, remote sensing and GIS technologies promise to yield deeper understandings of catchments such as Kyeamba Creek. Application of the current suite of models and techniques to other monitored catchments within the mid- Murrumbidgee would also help tie together our overall understanding of this region.

Monitoring of water levels in the north of the catchment is also important, with the groundwater pumping at Gumly Gumly likely to have a local influence. Possible work through manipulation of pumping times and volumes would allow an accurate characterisation of aquifer properties, and better describe the influence of the pumping scheme. Future management of shallow water levels through pumping would benefit from such a study.

Consistent and reliable data within Kyeamba Creek has only been collected for the last 25 years, a period that appears to be under a quasi-equilibrium flow regime. As such this data is most useful in modelling and analysing the current state, rather than providing insight into historical or future trends. With the planned introduction of a major plantation forestry project, this provides an excellent opportunity to observe changes in both surface and groundwater flows within a realistic time frame, in a catchment with a good baseline set of data.

27 CATCHMENT CHARACTERISATION, KYEAMBA CREEK CASE STUDY References

Baker, P, Please, P, Coram, J, Dawes, W, Bond, W, Stauffacher, M, Gilfedder, M, Probert, M, Huth, N, Gaydon, D, Keating, B, Moore, A, Simpson, R, Salmon, L & Stefanski, A 2001, Assessment of salinity management options for Upper Billabong Creek catchment, NSW: Groundwater and farming systems water balance modelling. National Land and Water Resources Audit, Canberra.

Beale, GTH, Beecham, R, Harris, K, O’Neill, D, Schroo, H, Tuteja, NK & Williams, RM 2000, Salinity prediction for NSW rivers in the Murray-Darling Basin. Centre for Natural Resources Report 99.048, NSW Department of Land and Water Conservation, Wagga Wagga.

Chen, XY & McKane, DJ 1996, Soil Landscapes of the Wagga Wagga, 1:100,000 Sheet. NSW Department of Land and Water Conservation, Wagga Wagga.

Coram, JE (ed.) 1998, National Classification of Catchments for land and river salinity control. RIRDC Publication No. 98/78, Rural Industries Research and Development Corporation, Canberra.

Coram, JE, Dyson, PR, Houlder, PA & Evans, WR 2000, Australian groundwater flow systems contributing to dryland salinity. Report by Bureau of Rural Science for the Dryland Salinity Theme of the National Land and Water Resources Audit, Canberra (CD contains report, maps, and spatial data).

Dawes, WR, Stauffacher, M & Walker, GR 2000, Calibration and modelling of groundwater processes in the Liverpool Plains. Technical Report 5/00, CSIRO Land and Water, Canberra, 41p.

Dawes, WR, Walker, GR & Stauffacher, M 1997, Model building: Process and practicality. In Proceedings of MODSIM 97 Volume 1, 8-11 December 1997, Hobart, A McDonald & M McAleer (eds.). Modelling and Simulation Society of Australia and New Zealand, Canberra, pp.317-322.

Dawes, WR, Walker, GR & Stauffacher, M 2001, Practical modelling for management in data-limited catchments. Mathematical and Computer Modelling, 33, 625-633.

Freeze, RA & Cherry, JA 1979, Groundwater. Prentice-Hall, Englewood Cliffs, New Jersey.

Harvey, F & Jones, H 2003, Maximising the information from discrete electrical conductivity samples in the third order catchments. CNR 2001.054. NSW Department of Infrastructure Planning & Natural Resources, Parramatta.

Hekmeijer, P, Dawes, W, Bond, W, Gilfedder, M, Stauffacher, M, Probert, M, Huth, N, Gaydon, D, Keating, B, Moore, A, Simpson, R, Salmon, L & Stefanski, A 2001, Assessment of salinity management options for Kamarooka, Victoria: Groundwater and crop water balance modelling. National Land and Water Resources Audit, Canberra.

Hekmeijer, P & Dawes, WR 2003, Assessment of Salinity Management Options for Axe Creek, Victoria: Data Analysis and Groundwater Modelling. CSIRO Land and Water Technical Report 22/03, Murray-Darling Basin Commission Publication 08/03, Canberra.

Lapsevic, PA, Novakowski, KS & Sudicky, EA 1999, Groundwater flow and solute transport in fractured media. In The Handbook of Groundwater Engineering. JW Delleur (ed.), CRC Press, New York.

Love, A & Cook, PG 1999, The importance of fractured rock aquifers. PIRSA Report Book 99/23, Primary Industries and Resources SA, Adelaide, 12p.

Page, KJ & Carden, YR 1998, Channel adjustment following the crossing of a threshold: Tarcutta Creek, Southeastern Australia. Australian Geographical Studies, 36, 289-311.

Short, R, Salama, RB, Pollock, D, Hatton, TJ, Bond, W, Paydar, Z, Cresswell, H, Gilfedder, M, Moore, A, Simpson R, Stefanski, A, Probert, M, Huth, N, Keating, B, Coram, J & Please, P 2000, Assessment of salinity management options for Lake Warden Catchments, Esperance, WA: Groundwater and crop water balance modelling. Technical Report 20/00, CSIRO Land and Water, Canberra.

Stauffacher, M, Bond, W, Bradford, A, Coram, J, Cresswell, H, Dawes, W, Gilfedder, M, Huth, N, Keating, B, Moore, A, Paydar, Z, Probert, M, Simpson, R, Stefanski, A & Walker, G 2000, Assessment of salinity management options for Wanilla, Eyre Peninsula: Groundwater and crop water balance modelling. Technical Report 01/00, CSIRO Land and Water, Canberra.

Summerell, GK 2001, Exploring mechanisms of salt delivery to stream within the Kyeamba valley catchment New South Wales, Australia. In Proceedings of MODSIM 2001, F Ghassemi, P Whetton, R Little & M Littleboy (eds.). Modelling and Simulation Society of Australia and New Zealand, Canberra, 627-631.

28 CATCHMENT CHARACTERISATION, KYEAMBA CREEK CASE STUDY Tuteja, NK, Beale, GTH, Summerell, G & Johnston, WH 2002, Development and validation of the Catchment Scale Salt Balance Model—CATSALT (Version 1). Technical Report, Centre for Natural Resources, NSW Department of Land and Water Conservation, Wagga Wagga.

Woolley, D 1991, Kyeamba Landcare Area Groundwater. Unpublished DLWC report to Kyeamba Landcare Group.

Zhang, L, Dawes, WR & Walker, GR 2001, Response of mean annual evapotranspiration to vegetation changes at catchment scale. Water Resources Research, 37, 701-708.

29 CATCHMENT CHARACTERISATION, KYEAMBA CREEK CASE STUDY 30 CATCHMENT CHARACTERISATION, KYEAMBA CREEK CASE STUDY Integrated catchment management in the Murray-Darling Basin A process through which people can develop a vision, agree on shared values and behaviours, make informed decisions and act together to manage the natural resources of their catchment: their decisions on the use of land, water and other environmental resources are made by considering the effect of that use on all those resources and on all people within the catchment.

Our values Our principles We agree to work together, and ensure that our We agree, in a spirit of partnership, to use the following behaviour reflects that following values. principles to guide our actions.

Courage Integration • We will take a visionary approach, provide leadership • We will manage catchments holistically; that is, and be prepared to make difficult decisions. decisions on the use of land, water and other environmental resources are made by considering Inclusiveness the effect of that use on all those resources and on • We will build relationships based on trust and all people within the catchment. sharing, considering the needs of future generations, and working together in a true Accountability partnership. • We will assign responsibilities and accountabilities. • We will engage all partners, including Indigenous • We will manage resources wisely, being communities, and ensure that partners have the accountable and reporting to our partners. capacity to be fully engaged. Transparency Commitment • We will clarify the outcomes sought. • We will act with passion and decisiveness, taking • We will be open about how to achieve outcomes the long-term view and aiming for stability in and what is expected from each partner. decision-making. Effectiveness • We will take a Basin perspective and a non- partisan approach to Basin management. • We will act to achieve agreed outcomes. • We will learn from our successes and failures and Respect and honesty continuously improve our actions. • We will respect different views, respect each other and acknowledge the reality of each other’s situation. Efficiency • We will act with integrity, openness and honesty, be fair • We will maximise the benefits and minimise the and credible and share knowledge and information. cost of actions. • We will use resources equitably and respect the Full accounting environment. • We will take account of the full range of costs and Flexibility benefits, including economic, environmental, social and off-site costs and benefits. • We will accept reform where it is needed, be willing to change, and continuously improve our actions Informed decision-making through a learning approach. • We will make decisions at the most appropriate scale. Practicability • We will make decisions on the best available • We will choose practicable, long-term outcomes information, and continuously improve knowledge. and select viable solutions to achieve these • We will support the involvement of Indigenous outcomes. people in decision-making, understanding the value of this involvement and respecting the living Mutual obligation knowledge of Indigenous people. • We will share responsibility and accountability, and act responsibly, with fairness and justice. Learning approach • We will support each other through the necessary • We will learn from our failures and successes. change. • We will learn from each other.