DRAFT REPORT: Stream type assessment of the Mackay-Whitsundays region

March 2017

Document history

Revision: Revision no. 01 Author/s Misko Ivezich Jacqui Reid

Checked Ross Hardie/Steve Skull Approved Misko Ivezich

Distribution: Revision no. 01 Issue date March 2017 Issued to Chris Dench (Reef Catchments)

Description: Draft for comment

Citation: Draft for comment - please do not cite.

Acknowledgements: We would like to acknowledge and thank the following people for their input in this review:

Chris Dench (Reef Catchments)

Paul Grove from the Great Barrier Reef Marine Park Authority (GBRMPA)

Ref: V:\Projects\Brisbane_Projects_2016\018_Mackay_Whitsunday_Stre am_Classification\1_Deliverables\P416018_R01_Mackay_Whitsunda ys_stream_type_assessment_draft_for_comment.docx

Contents

1 Introduction 1 1.1 Background 1 1.2 Study objectives 2 1.3 Report structure 2 2 Study area 3 2.1 Landscape 3 2.2 Climate 5 2.3 Geology/soils 7 2.4 Land use 7 3 Approach 11 3.1 Overview 11 4 Stream type assessment 13 Edgecumbe Bay 15 Overview 15 Stream type assessment 15 Riparian vegetation condition 15 Stability 16 Physical form values 16 Sediment connectivity 16 4.1 Repulse Bay 19 Overview 19 Stream type assessment 19 Riparian vegetation condition 20 Stability 21 Physical form values 21 Sediment connectivity 21 4.2 Whitsunday Coast 25 Overview 25 Stream type assessment 25 Riparian vegetation condition 25 Stability 25 Physical form values 25 Sediment connectivity 25 4.3 Seaforth Coast 28 Overview 28 Stream type assessment 28 Riparian vegetation condition 29 Stability 29 Physical form values 29 Sediment connectivity 29 4.4 Sandringham Bay 32 Overview 32 Stream type assessment 32 Riparian vegetation condition 34 Stability 34 Physical form values 35 Sediment connectivity 35

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4.5 Sarina Inlet 38 Overview 38 Stream type assessment 38 Riparian vegetation condition 38 Stability 38 Physical form values 38 Sediment connectivity 39 4.6 Ince Bay 42 Overview 42 Stream type assessment 42 Riparian vegetation condition 43 Stability 43 Physical form values 43 Sediment connectivity 43 4.7 Carmila Coast 46 Overview 46 Stream type assessment 46 Riparian vegetation condition 46 Stability 47 Physical form values 47 Sediment connectivity 47 5 Summary 51 6 References 52

Attachment A Stream type assessment method 53 Stream type method 54 Primary channel assessment 54 Inset channel assessment 56 Overall channel stability 57 Sediment regime and connectivity 57 Instream habitat 58 Physical form condition 58

Figures Figure 1. Project Study area – major management basins outlined in red 1 Figure 2. Elevation throughout the Mackay-Whitsundays study area showing high relief associated with the Clark Conner Range 4 Figure 3. Rainfall data from Crediton (33172) and Mackay (33119) showing the variability in monthly rainfall. These stations are located near the centre of Mackay- Whitsundays region. 5 Figure 4. Rainfall variability within the study area demonstrated by mean annual rainfall isohyets between the years 1920 to 1969 6 Figure 5. Geology within the study area 8 Figure 6. Soil types within the study area 9 Figure 7. Land use within the Mackay-Whitsundays region 10 Figure 9. The eight receiving waters and their catchments across the Mackay Whitsundays region 14 Figure 10. Section of Emu Creek which is slightly confined by bedrock 15 Figure 11. Significant weed growth within the upper floodplain reach of Gregory River 16 Figure 12. Stream types within the Edgecumbe Bay receiving waters catchment 17 Figure 13. Riparian vegetation condition within the Edgecumbe Bay receiving waters catchment 18 Figure 14. Channel stability within the Edgecumbe Bay receiving waters catchment 18 Figure 15. Inset channel of the Proserpine River within a larger macrochannel 19 Figure 16. Riparian vegetation along the lower Proserpine River 20 Figure 17.Good riparian vegetation within the macrochannel of the Andromache River 21

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Figure 18. Stream types within the Repulse Bay receiving waters catchment 22 Figure 19. Riparian vegetation condition within the Repulse Bay receiving waters catchment 23 Figure 20. Channel stability within the Repulse Bay receiving waters catchment 24 Figure 21. Degraded riparian vegetation in Campbell Creek 25 Figure 22. Stream types within the Whitsundays Coast receiving waters catchment 26 Figure 23. Riparian vegetation condition within the Whitsundays Coast receiving waters catchment 27 Figure 24. Channel stability within the Whitsundays Coast receiving waters catchment 27 Figure 25. Blackrock Creek, significantly confined by terraces. There is good riparian vegetation within the macrochannel. 28 Figure 26. Poor riparian vegetation within St Helens Creek with exotic groundcovers dominating the riparian zone 29 Figure 27. Stream types within the Seaforth Coast receiving waters catchment 30 Figure 28. Riparian vegetation condition within the Seaforth Coast receiving waters catchment 31 Figure 29. Channel stability within the Seaforth Coast receiving waters catchment 31 Figure 30. Cattle Creek, upstream of the Pioneer River confluence, has a macro-channel morphology which is significantly confined by terraces 33 Figure 31. Lower Sandy Creek is significantly confined by the adjacent terraces 33 Figure 32. Excellent riparian vegetation within McGregor Creek which is significantly confined by terraces 34 Figure 33. Engineered Log Jams and revegetation have been used to limit bank erosion in Owen Creek 35 Figure 34. Stream types within the Sandringham Bay receiving waters catchment 36 Figure 35. Riparian vegetation condition within the Sandringham Bay receiving waters catchment 37 Figure 36. Channel stability within the Sandringham Bay receiving waters catchment 37 Figure 37. Lower Plane Creek which is slightly confined by terraces; through this section both banks abut inset floodplain units 38 Figure 38. A section of Plane Creek which has significant weed infestation 39 Figure 39. Stream types across the Sarina Inlet receiving waters catchment 40 Figure 40. Riparian vegetation condition within the Sarina Inlet receiving waters catchment 41 Figure 41. Channel stability within the within the Sarina Inlet receiving waters catchment 41 Figure 42. Bedrock intrusion in Rocky Dam Creek 42 Figure 43. Stock tracks impacting riparian vegetation condition within upper Cherry Tree Creek 43 Figure 44. Stream types within the Ince Bay recieving waters catchment 44 Figure 45. Riparian vegetation within the Ince Bay recieving waters catchment 45 Figure 46. Channel stability within the Ince Bay recieving waters catchment 45 Figure 47. Bedrock controls within Gillinbin Creek 46 Figure 48. Riparian vegetation condition is poor in Carmila Creek near the Bruce Highway 47 Figure 49. Stream types within the Carmila Coast receiving waters catchment 48 Figure 50. Riparian vegetation condition within the Carmila Coast receiving waters catchment 49 Figure 51. Channel stability within the Carmila Coast receiving waters catchment 50 Figure 52. Stages of channel incision 56

Tables Table 1. Mackay-Whitsundays catchment areas and lengths of stream 3 Table 2. Overview of the key elements assessed in this report 11

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1 Introduction

Alluvium Consulting Australia Pty Ltd (Alluvium) has been engaged by Reef Catchments to undertake a stream type assessment of waterways across the Mackay-Whitsundays region (Figure 1). The waterways within the Mackay-Whitsundays region typically drain the eastern slopes of the Clarke Connors Range before flowing east and discharging in the Great Barrier Reef Marine Park (GBRMP). Channel erosion and degraded riparian vegetation within these waterways are factors that contribute to significant sediment and nutrient loads to the GBRMP. An understanding of the fluvial geomorphology, stream physical form and riparian condition can help inform broader catchment management responses to protect the Great Barrier Reef and improve river health.

Figure 1. Project Study area – major management basins outlined in red

1.1 Background Stream channels are the primary conduits for the delivery of catchment derived sediments and nutrients to the coast. Sediments can be derived from hillslopes, gullies and channel erosion. These sediments are periodically stored in a geomorphic units including floodplains, benches, bars and islands. These geomorphic units can exert significant control on waterway processes and impact on how sediments are transported and stored within the fluvial system.

Adjustments to channel form occur as a result of relationships that exist between channel form, flow and sediment supply and transport. At the reach-scale, the type of adjustment that can take place is constrained by the valley setting, the nature of bed and bank materials, and riparian vegetation. This gives rise to a wide diversity of different channel forms (or stream types). Understanding the stream types across a region can greatly assist in understanding waterway condition and sediment transport and storage processes.

Vegetation plays an important role in these processes. Erosion is a natural and essential process in alluvial systems; however human activities such as land clearing, removal of riparian vegetation or grazing pressure that limits reestablishment of vegetation can result in accelerated rates of channel erosion and sediment

Stream type assessment of the Mackay-Whitsundays region 1

delivery. In addition, vegetation within channels and floodplains can play a critical role in capturing and stabilising sediments transported through channel networks. The condition of riparian vegetation is an important factor in sediment generation, transport and delivery

This study aims to provide an overview of the stream types and their condition (including riparian vegetation condition) to assist Reef Catchment in future waterway management programs.

1.2 Study objectives Reef Catchments have sought a high-level assessment of waterways across the Mackay Whitsundays region. The assessment aims to identify stream reaches that can play a critical role in reducing sediment and nutrient delivery to the coast.

The specific objectives of the assessment are to identify:

• The type of stream (i.e. the channel form and boundary conditions).

• The current condition/stability of the channel

• The riparian vegetation condition

• The physical form values of the waterway

• The connectivity of each stream to the Great Barrier Reef This stream type assessment has comprised a high-level assessment of existing geomorphic condition. It does not provide detailed assessment of historic and active geomorphic processes and has only included (Strahler) third order streams and higher have been assessed. The assessment has sought to provide sufficient overview of geomorphic condition to inform catchment management programs which will need to consider broader catchment processes (i.e. agricultural runoff, urban runoff, hillslope and gully erosion etc.) and ecological condition. Assessments of other catchment attributes and processes can be found in Department of Environment, Heritage and Planning’s (DEHP) Walking the Landscape outputs and the Great Barrier Reef Marine Park Authority’s (GBRMPA) Application of the whole of systems management framework reports within the region.

1.3 Report structure The assessment is presented in the following sections in this report:

• Section 2 presents an overview of the study area

• Section 3 provides an overview of the methods used during the assessment

• Section 4 presents the findings from the assessment

• Section 5 summarises the findings of the assessments and provides recommendations for future management actions

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2 Study area

2.1 Landscape The waterways of the Mackay-Whitsundays region rise on the eastern slopes of the Clarke Connors Ranges and flow in an easterly direction before discharging directly into the GBRMP. Elevations within the catchments range from over 1200 m AHD in the Clarke Connors Ranges to sea level at the coast (Figure 2). However, apart from the headwaters in the Clarke Connors Ranges, the majority streams flow through relatively low relief and gently sloping landscapes across the coastal floodplain.

Four major basins are defined within the region. There are also eight distinct receiving waters which have been defined within the region. The basin areas, receiving waters and lengths of stream per stream order are outlined in Table 1. The Proserpine, O’Connell and Plane Creek catchments contain distributed stream networks with many significant and minor streams that drain directly to the GBR lagoon. The Pioneer River catchment has all streams draining into the Pioneer River before discharging into the Sandringham Bay receiving waters in Mackay.

Table 1. Mackay-Whitsundays catchment areas and lengths of stream

Total length Receiving SO3 SO4 SO5 SO6 Basin Area (km²) of stream waters (km) (km) (km) (km) (>SO3) (km)

Edgecumbe Bay Whitsunday Proserpine Coast 1494 564 344 152 63 6 River Repulse Bay (North) Repulse Bay O’Connell (South) 2387 605 344 165 74 22 River Seaforth Coast Sandringham Pioneer River 1570 553 309 89 70 84 Bay (North) Sandringham Bay (South) Plane Creek Sarina Inlet 2540 694 352 247 95 - Ince Bay Carmilla Coast

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Figure 2. Elevation throughout the Mackay-Whitsundays study area showing high relief associated with the Clark Conner Range

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2.2 Climate The Mackay-Whitsundays region experiences a sub-tropical climate with summer dominated rainfall and high inter and intra annual variability (Figure 3). Extremely intense rainfall events have been recorded in the region, generally associated with cyclonic activity and southerly excursions of the monsoon trough (Hacker, 1988). Annual rainfall typically ranges from 800 mm/year to up to 3000 mm/year across the region (Figure 4). Typically, higher rainfall is experienced in the upper catchment where orographic impacts are dominant, except in parts of the upper Pioneer River catchment, which are in a rain shadow due to the dominate south- easterly breezes. Low annual rainfalls also occur in the northern region of the study area near Bowen.

Figure 3. Rainfall data from Crediton (33172) and Mackay (33119) showing the variability in monthly rainfall. These stations are located near the centre of Mackay- Whitsundays region.

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Figure 4. Rainfall variability within the study area demonstrated by mean annual rainfall isohyets between the years 1920 to 1969

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2.3 Geology/soils The geology of the upper catchments is dominated by intrusive granitoid units from the late Carboniferous to early Permian period which now form the steep, mountainous regions associated with the Clark Conner Range (Figure 5). These igneous granitoids are highly erosive and weather to sands and clays.

The other major unit in the Mackay Whitsundays region is the early Permian Carmila beds which consist of a mix of volcanics and sedimentary rocks. This unit primarily forms the lower hillslopes across the region.

The alluvial/colluvial deposits consist of clays, silts and sands in which the waterways have developed. There are also extensive terrace formations throughout the region which are more resistant to erosion than the Holocene floodplain deposits.

Soils in the southern half of the region are dominated by dermasols with a sealing loamy surface (Figure 6). Dermasols can vary from stony hardsetting soils to friable deeper profiles. Within the region these dermasols are typically non-sodic. Sodosols with a loamy surface are dominant in the northern half of the catchment. These sodosols include sodic chromosols/kurosols/kandosols and calcaros. Approximately half of the streams within the region traverse the dermasols soil type and one quarter flow through the sodosols.

2.4 Land use Land use within the region is dominated by agricultural enterprises (Figure 7). Approximately 44 % of the region is used for grazing, whilst a further 18 % is used for irrigated sugarcane production. Sugarcane is a significant economic driver for the region and the Mackay Whitsundays produces up to one third of Queensland’s sugarcane harvest (Jupiter and Marion, 2008). Sugarcane production is predominantly located on the floodplain and terraces, however in some locations it extends into the steeper foothills. The hillslopes are dominated by cattle grazing. Approximately 10 % of the region is comprised of production forestry, which is generally located on the hillslopes. Nature conservation accounts for approximately 8 % of the region, which is typically located in state forests and national parks, such as the Eungella, Dryander, Cape Palmerston and Conway National Parks and the Proserpine, Cathu and Mia Mia State Forests.

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Figure 5. Geology within the study area

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Figure 6. Soil types within the study area

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Figure 7. Land use within the Mackay-Whitsundays region

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3 Approach

3.1 Overview The assessment adopted for the investigation has used many aspects of other stream type assessments such as RiverStylesTM (Brierley G, & Fryirs K, 2005). However, the method has been adapted to address specific issues within GBR catchments. Many rivers in the region do not necessarily have a ‘classic’ floodplain morphology and do not behave like true self-formed alluvial rivers. Many rivers in the region (and across Queensland) have a macro-channel bounded by resistant old floodplain/terrace deposits. Within the macro- channel an inset channel and a range of geomorphic units (e.g. bars, benches, islands, inset floodplains) can exist. The proposed method allows these stream types to be assessed.

The assessment utilised spatial analysis of LiDAR data and aerial imagery (including historic aerial imagery) supported by targeted field assessments. The fields assessments were undertaken by Misko Ivezich (Alluvium), Chris Dench (Reef Catchments) and Paul Grove (Great Barrier Reef Marine Park Authority) between 28th of November and 2nd of December 2017. A total of 108 sites were visited across the Mackay Whitsundays region. During the field assessment observations relating to bed and bank material/morphology, riparian vegetation condition and instream habitat were recorded.

A detailed overview of the overall stream type assessment is provided in Attachment A. However, an overview of the key assessments, which are primarily discussed in this report, is presented in Table 2.

Table 2. Overview of the key elements assessed in this report

Element Description

Stream type The stream type primarily relates to the degree of confinement and planform (i.e. meandering, low sinuosity).

An alluvial channel can be confined (i.e. lateral adjustment of the channel is limited) by either:

• Bedrock valley margins

• Resistant terrace features (typically highly resistant silts and clays)

Alluvial channels can be confined to varying degrees by both terraces and bedrock valley margins. For this assessment, the degree of lateral confinement was assessed as either confined, significantly confined, slightly confined or unconfined (see Attachment A for more details).

Riparian A higher-level assessment of riparian vegetation condition was undertaken. For this vegetation assessment canopy cover was used as a surrogate for root reinforcement and hydraulic resistance along channel banks. The assessment utilised aerial imagery and field assessments and used a four-tier rating system of good, moderate, poor and very poor (see Attachment A for more details).

Stability The channel stability assessment considered both the lateral stability of the channel (i.e. meander migration, channel widening) and the stability of inset units within macrochannel systems (see Attachment A for more details).

Physical The assessment of physical form values included a higher-level assessment of instream form values habitat at the field assessment sites and the assessment of riparian vegetation condition. The location of weirs and dams were also part of the assessment. (see Attachment A for more details)

Stream type assessment of the Mackay-Whitsundays region 11

Sediment A high level assessment of the downstream sediment buffers (floodplains, channels etc. ) connectivity and barriers (reservoirs and weirs) was undertaken to determine the reach sediment transport connectivity to the GBR lagoon.

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4 Stream type assessment

The Mackay Whitsundays region has eight distinct receiving waters which include:

1. Edgecumbe Bay 5. Sandringham Bay

2. Repulse Bay 6. Sarina Inlet

3. Whitsunday Coast 7. Ince Bay

4. Seaforth Coast 8. Carmila Coast

The catchments which drain into these eight receiving waters are shown in Figure 8. Within the eight receiving waters contributing catchments there are 33 sub-catchments which are utilised in Reef Catchments in their Water Quality Improvement Plans (WQIPs). The findings from this stream type and condition assessment for each receiving waters catchment are summarised below.

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Figure 8. The eight receiving waters and their catchments across the Mackay Whitsundays region

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Edgecumbe Bay

Overview Edgecumbe Bay is a north facing bay that lies just south of the township of Bowen. The major waterways that drain into the Edgecumbe Bay include Duck Creek, Emu Creek, Yeates Creek, Eden Lasse Creek (all part of the Eden Lasse Creek sub-catchment) and Gregory River (part of Gregory River sub-catchment).

The catchment is relatively low relief except for the Gregory River headwaters. The majority of the catchment supports grazing land use. The southern area of the Gregory River sub-catchment supports sugar cane cultivation.

Stream type assessment The stream types within the Edgecumbe Bay receiving waters catchment are presented in Figure 11. The majority of the waterways within the Eden Lasse Creek sub-catchment are either slightly confined or significantly confined by bedrock (Figure 9). Within the valley confines there are some alluvial deposits with the most extensive floodplain deposits located in the lower Eden Lasse Creek system. The lower reaches of waterways within the Eden Lasse Creek sub-catchment are unconfined. These streams have a sinuous planform within the estuarine floodplains and mudflats.

Figure 9. Section of Emu Creek which is slightly confined by bedrock

The headwaters of Gregory River flow through steep, bedrock confined valleys with only minor floodplain development. At the base of the hillslopes the Upper Gregory River flows into an alluvial valley with extensive floodplain development (supports sugar cane cultivation) . The mid reaches of Gregory River are significantly confined by the adjacent bedrock associated with the low relief hills with only minor alluvial development. The lower estuarine reach is unconfined with a meandering planform.

Riparian vegetation condition Riparian vegetation condition in the Repulse Bay receiving waters is presented in Figure 12. Riparian vegetation is in a good condition in the upper reaches of Gregory River, Emu Creek, Yeates Creek and some sections of upper Eden Lasse Creek. The majority of reaches have moderate condition riparian vegetation due to adjacent stock and weed pressures. Significant weed infestation was observed in section in Gregory River (Figure 10).

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Figure 10. Significant weed growth within the upper floodplain reach of Gregory River

Stability Channel stability in the Edgecumbe Bay receiving waters contributing catchment is presented in Figure 13. There are no significant instabilities within the major waterways. Generally, waterways are either stable or show minor instabilities associated with localised bank erosion. The localised bank erosion may have been exacerbated by stock impacts as grazing is widespread through the catchment. Lateral adjustment as part of meander migration processes is common in the lower estuarine reaches.

Physical form values The majority of waterways had moderate to good physical form values. A significant length of the upper Gregory River is in poor condition due to extensive instream weeds. Reaches within Eden Lasse Creek subcatchment have limited bed diversity, with weed and stock impacts further contributing to its poor condition. Physical form values have typically been least impacted in the headwaters and estuary reaches.

Sediment connectivity A large portion of sediment derived from hillslopes and inchannel erosion is likely to be transported to Edgecumbe Bay. There is minimal floodplain storage except for the lower estuarine floodplains and tidal flats and the upper Gregory River floodplain. The upper Gregory River floodplain is only likely to be inundated in large flow events and thus would only provide limited buffering capacity. The lower estuarine floodplains are likely to be the major sediment storages in the catchment and act as significant buffers to sediment delivery to the bay.

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Figure 11. Stream types within the Edgecumbe Bay receiving waters catchment

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Figure 12. Riparian vegetation condition within the Edgecumbe Bay receiving waters catchment

Figure 13. Channel stability within the Edgecumbe Bay receiving waters catchment

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4.1 Repulse Bay

Overview Repulse Bay faces east and lies to the south of the Conway Range. Both the O’Connell River and Proserpine River catchments drain into Repulse Bay making it one of the largest receiving waters contributing catchment in the Mackay Whitsundays region.

The major tributaries of the Proserpine River include Myrtle Creek to the east and Lethe Brook to the south. The major tributary of O’Çonnell River is the Andromache River catchment which drains the north-western area of the catchment. Between the Proserpine River and O’Connell River catchments Thompson Creek drains into Repulse Bay. To the south of the O’Connell River catchment the Waterhole Creek subcatchment drains into the southern area of the receiving waters.

The majority of the Repulse Bay catchment is used for grazing. There are also significant areas of sugarcane production primarily on the alluvial terrace units. The Peter Faust Dam was constructed on the Upper Proserpine River in the 1970s and supplies water to the surrounding urban and agricultural areas.

Stream type assessment The stream types within the Repulse Bay receiving waters are presented in Figure 17. Downstream of the Peter Faust Dam the Proserpine River is significantly confined by adjacent terraces. The system is predominately a sand bed stream with a small inset channel (Figure 14). Within the macrochannel there are inset floodplains which are now rarely inundated due to the reduction in high flows due to the dam. The lower reaches of the Proserpine River are unconfined with meandering planform.

Figure 14. Inset channel of the Proserpine River within a larger macrochannel

Within the Myrtle Creek sub-catchment streams drain west off the Conway Range and are either confined, or slightly confined by the bedrock associated with the range.

Upper Lethe Brooke is significantly confined by terraces. In the southern area of the Lethe Brooke subcatchment Silver Creek, Victoria Creek and Gooranga Creek are confined by a mix of bedrock features and terraces. Lower Lethe Brooke is unconfined with a meandering planform through to the estuary zone.

The reaches in upper Thomson Creek are slightly or significant confined by terraces before flowing into an unconfined swampy landscape. Through this section, Thomson Creek has a meandering planform.

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The upper Andromache River is confined or significantly confined by bedrock. The lower Andromache River is significantly confined by terraces with a sand bed. Within the macrochannel there are sandy loam benches and inset floodplains.

The upper O’Connell River is confined or significantly confined by bedrock. The mid and lower reaches of the O’Connell River have macrochannel morphology which is slightly or significantly confined by terraces. Within the macrochannel there are discontinuous pockets of inset floodplains. Major tributaries of the O’Connell River including Boundary Creek, Big Cedar Creek and Horse Creek are also significantly confined by terraces and bedrock features.

Terraces also significantly confine waterways in the Upper Waterhole Creek catchment. In the lower reaches of Waterhole Creek the system is unconfined with a meandering planform.

Riparian vegetation condition Riparian vegetation condition in the Repulse Bay receiving waters contributing catchment is presented in Figure 18.Downstream of Peter Faust Dam, riparian vegetation is in moderate condition with good native vegetation fringing the low flow channel. Further downstream in the mid reaches riparian vegetation is poor and dominated by weeds. The lower Proserpine River has relatively good vegetation coverage (Figure 15).

Figure 15. Riparian vegetation along the lower Proserpine River

Riparian vegetation throughout Lethe Brook subcatchment is in good condition. Within Thompson Creek riparian vegetation is relatively good in the upper reaches and lower estuary. Through the mid-section of the sub-catchment, within the ponded pasture area, riparian vegetation is highly degraded.

In the Upper Andromache River catchment where the channel is more accessible to cattle riparian vegetation is in a poor condition. In the lower Andromache River riparian vegetation within the macrochannel is relatively good (Figure 16).

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Figure 16.Good riparian vegetation within the macrochannel of the Andromache River

Within the O’Connell River riparian vegetation condition is sporadic. There are isolated pockets of good remnant native riparian vegetation throughout the system however for the most part the riparian zone is in poor to moderate condition. Boundary Creek a major tributary of the O’Connell has good riparian vegetation for most of its length.

Riparian vegetation within the Waterhole Creek subcatchment is variable with sections in good, moderate and poor condition reflecting the adjacent grazing land use.

Stability Channel stability in the Repulse Bay receiving waters contributing catchment is presented in Figure 19. The majority of waterways within the Repulse Bay catchment are either stable or experience minor instabilities. The major channel instabilities occur along the main stem of the O’Connell River and Cattle Creek which is a tributary of the upper Andromache River. Within the O’Connell River channel erosion typically occurs from inset floodplain units which lie within the macrochannel. When riparian vegetation is removed, or degraded by stock, these inset features are highly vulnerable to erosion.

Physical form values The Lethe Brooke and Myrtle Creek subcatchments have maintained good instream and riparian habitat. Within the lower Proserpine River physical form is degraded due to flow regulation and instream weeds. In the O’Connell River and Andromache River deep pools have largely been lost due to increased sand loads and loss of instream roughness (i.e. vegetation, large wood etc.).

Sediment connectivity The major sediment barrier in the system in the Repulse Bay catchment is the Peter Faust Dam which is likely to capture significant volumes of fine grained and coarse grained sediments. Both the O’Connell River and Andromache River are relatively well connected to Repulse Bay with limited sediment buffers except for on inset floodplains and inchannel storage. The lower estuarine floodplain has a small area and is only likely to provide minimal buffering capacity

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Figure 17. Stream types within the Repulse Bay receiving waters catchment

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Figure 18. Riparian vegetation condition within the Repulse Bay receiving waters catchment

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Figure 19. Channel stability within the Repulse Bay receiving waters catchment

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4.2 Whitsunday Coast

Overview In the northern Whitsunday Coast area a number of small waterways drain to the east into the Whitsunday Channel. These include Miralda Creek, Charley Creek, Airlie Creek and The Inlet (part of Whitsunday Coast sub- catchment). In the southern area, Repulse Creek drains into the northern section of Repulse Bay.

The catchment is predominately remnant rainforest and large areas are protected by The Conway Range and Dryander National Parks. Airlie Beach and Cannonvale are the main urban developments within the Whitsunday Coast receiving waters catchment.

Stream type assessment The stream types within the Whitsundays Coast region are presented in Figure 21. The majority of waterways are confined by bedrock as the dissect the steep Conway Range. These waterways are likely to be steep, with boulder bars and bedrock outcrops within the channel. In the lower reaches along the coastal fringes floodplains and tidal flats are formed.

Riparian vegetation condition Riparian vegetation condition within the Whitsundays Coast region is presented in Figure 22. The riparian vegetation condition is largely intact with rainforest in the upper catchment and mangrove/saltmarsh communities in the estuaries. Campbell Creek through Airlie Beach has degraded riparian vegetation as a result of the adjacent urban development (Figure 20).

Figure 20. Degraded riparian vegetation in Campbell Creek

Stability Waterways within the Whitsundays Coast receiving waters catchment are generally stable (Figure 23). This is due to the significant bedrock control and limited alluvial development along waterways. No major instabilities were observed.

Physical form values There are good physical form values in the majority of waterways except for reaches impacted by urbanisation. Repulse Creek, the largest waterway in the Whitsundays Coast receiving waters catchment maintains excellent values from the estuary to the headwaters.

Sediment connectivity Most waterways are highly connected to the coast. The floodplains and tidal flats along the lower reach of Repulse Creek provide the major sediment storage within the catchment.

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Figure 21. Stream types within the Whitsundays Coast receiving waters catchment

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Figure 22. Riparian vegetation condition within the Whitsundays Coast receiving waters catchment

Figure 23. Channel stability within the Whitsundays Coast receiving waters catchment

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4.3 Seaforth Coast

Overview The Seaford Coast is a 45 km stretch of coast line to the north of Mackay. The coastline consists of a number of small bays and inlets. The Seaford Coast receiving waters consists of the Blackrock Creek, St Helens Creek, Murray Creek, Constant Creek and Reliance Creek subcatchments. These systems drain the south-western hillslopes and generally flow in a north eastern direction to the coast.

The major land uses within the Seaford Coast receiving waters are grazing and sugarcane production. There are also significant areas of the upper catchment which contain remnant forests.

Stream type assessment The stream types within the Seaforth Coast receiving waters contributing catchment is presented in Figure 26. The headwaters of Blackrock Creek, St Helens Creek, Murray Creek and Constant Creek dissect the north east hillslopes of the Clarke Connors Range creating bedrock confined reaches. At the base of the Clarke Connor Range alluvial floodplains and terraces form within the valley. Within these sections there are both active floodplains and older terraces. Waterways at the base of the range are either slightly or significantly confined by bedrock (where the active floodplains are more extensive) or terraces (where there is limited active floodplain development).

The valleys of Murray Creek and St Helens Creek are the steepest in the Mackay Whitsundays region. Both these waterways have a wider macrochannel with extensive floodplain development. As a result, it is the bedrock (rather than the terraces) which provides the major control to planform adjustment.

Many waterways within the Seaford Coast receiving waters catchment are significantly confined by terraces. These include the mid reaches of the Black Rock Creek (Figure 24), significant lengths of the southern tributaries of Murray Creek (i.e. Silent Grove Creek, Jolimont Creek and Hornet Gully) and the mid reaches of Constant Creek.

Figure 24. Blackrock Creek, significantly confined by terraces. There is good riparian vegetation within the macrochannel.

In the lower reaches of Blackrock Creek, St Helens Creek, Murray Creek, Constant Creek and Reliance Creek there is more extensive floodplain development. However, many of these reaches are still slightly confined by either bedrock or terraces. The estuarine reaches of St Helens Creek and Murray Creek are unconfined and meander across a wide estuarine floodplain.

Stream type assessment of the Mackay-Whitsundays region 28

Riparian vegetation condition Riparian vegetation condition in the Seaforth Coast receiving waters is presented in Figure 27. Riparian vegetation is in a good condition in the northern tributaries of Black Rock Creek. Vegetation in the southern tributary is more degraded ranging in condition from moderate to poor. Within St Helens Creek riparian vegetation is predominately in a poor condition (Figure 25).

Figure 25. Poor riparian vegetation within St Helens Creek with exotic groundcovers dominating the riparian zone

The main stem of Murray Creek also has significant areas of poor riparian vegetation due to extensive stock access to the riparian zone and channel. The riparian vegetation condition in the southern tributaries of Murray Creek improves and typically ranges from moderate to good although there are still significant weed impacts.

The main stem of Constant Creek has variable riparian vegetation condition ranging from poor to good. Generally, condition improves within the tributaries which predominately have good riparian vegetation condition.

Stability Channel stability in the Seaforth Coast receiving waters is presented in Figure 28. Across the Seaforth Coast receiving waters catchment the channels are predominately stable or experience minor instabilities. The primary channel instabilities within the catchment occur within St Helens Creek, the mid reaches of Murray Creek and a reach of the southern tributary of Black Rock Creek. Each of these reaches has limited terrace confinement and extensive floodplain development. Erosion within these reaches occurs as lateral channel adjustment into these floodplain deposits which typically have poor riparian vegetation coverage.

Physical form values Physical form values are most degraded in St Helens Creek and the mid reaches of Murray Creek. Within these reaches riparian vegetation coverage is sporadic and the channels are wide, shallow and contain limited physical form diversity. Elsewhere the physical form values are either good or moderate indicating there is good potential for restoration given the small catchments.

Sediment connectivity The streams within the Seaforth Coast receiving waters catchment are highly connected to the ocean. There are no major barriers for sediment transport to the marine environment. The floodplains in the lower catchment will provide some buffering capacity however this is likely to be minor. Given the short catchment lengths, sediment mobilised within these streams has a high likelihood of reaching the coastline.

Stream type assessment of the Mackay-Whitsundays region 29

Figure 26. Stream types within the Seaforth Coast receiving waters catchment

Stream type assessment of the Mackay-Whitsundays region 30

Figure 27. Riparian vegetation condition within the Seaforth Coast receiving waters catchment

Figure 28. Channel stability within the Seaforth Coast receiving waters catchment

Stream type assessment of the Mackay-Whitsundays region 31

4.4 Sandringham Bay

Overview The Sandringham Bay receiving waterways is positioned directly to the south of Mackay city. The Pioneer River which flows through Mackay is the major waterway which drains into Sandringham Bay. The receiving waters catchment is the largest in the Mackay-Whitsundays.

The major tributaries of the Pioneer River include Cattle Creek to the north and Blacks Creek in the south. To the south of the Pioneer River catchment Bakers Creek, Sandy Creek and Alligator Creek also drain into Sandringham Bay. The lower reaches of all these waterways flow across a large interconnected alluvial plain.

The majority of the Sandringham Bay catchment is used for sugarcane production primarily on the alluvial floodplain zones. There are also significant areas of grazing particularly in the Cattle Creek catchment. The hydrologic regime has been significantly altered within these sub-catchments; a number of dams and weirs and inter-catchment transfers operate to support the sugarcane production.

Stream type assessment The stream type assessment across the Sandringham Bay receiving waterways catchment is presented in Figure 33. Cattle Creek dissects the Clarke Connors Range and forms an alluvial valley. Within the valley there are both active floodplains and remnant terrace features. The main stem of Cattle Creek is slightly confined by these terraces. There are also several bedrock outcrops within the bed of Cattle Creek. Several tributaries in the upper catchment are slightly confined by steep bedrock valleys. Owen Creek, a major tributary of Cattle Creek, has a sinuous planform which is slightly confined by terraces.

Blacks Creek and its tributaries drain a large area of the Clarke Connors Range and primarily flow through steep bedrock controlled valleys. There is limited floodplain development within the Blacks Creek sub- catchment with the exception of some discontinuous floodplain pockets in the mid reaches of Blacks Creek.

Both Cattle Creek and Blacks Creek join to form the Pioneer River. Upstream of their confluence both Cattle Creek and Blacks Creek are significantly confined by terraces (Figure 29). Downstream of the confluence the main stem of the Pioneer River has a similar morphology with a large macro-channel that is significantly confined by the adjacent alluvial terraces. There are also several bedrock controls within the channel, which support the three main weirs within the river.

A number of waterways flow into the main stem of Pioneer River from the north including McGregor Creek. All these waterways are also significantly confined by the extensive alluvial terraces which adjoin the Pioneer River.

Stream type assessment of the Mackay-Whitsundays region 32

Figure 29. Cattle Creek, upstream of the Pioneer River confluence, has a macro-channel morphology which is significantly confined by terraces

Within Bakers Creek sub-catchment there are some unconfined reaches in the headwaters at the base of the ranges. Many of these waterways have been channelised; most likely to reduce inundation of the adjacent floodplains. Further downstream the tributaries become more incised into the Pioneer River alluvial deposits and are significantly confined by these terraces. Lower Bakers Creek has a meandering planform with extensive areas of inset floodplains within the confines of the terraces.

The headwaters of Sandy Creek drain the southern slopes of the Clarke Connors Range. The southern headwater streams are slightly confined by bedrock associated with the ranges. To the north of the upper catchment there are also unconfined reaches. The lower Sandy Creek system is significantly confined by terraces (Figure 30). The estuarine reach of Sandy Creek is unconfined with a meandering planform.

Alligator Creek also drains the southern slopes of the Clarke Connors Range. At the base of the range the Alligator Creek tributaries are incised in the alluvial terraces. The majority of Alligator Creek is significantly confined by these terraces. The lower reach has extensive inset floodplains and is only slightly confined by the surrounding terraces.

Figure 30. Lower Sandy Creek is significantly confined by the adjacent terraces

Stream type assessment of the Mackay-Whitsundays region 33

Riparian vegetation condition Riparian vegetation condition within the Sandringham Bay receiving waters catchment is presented in Figure 34. Within the Pioneer River catchment, the Blacks Creek sub-catchment largely retains native forest as there is limited agricultural activity. Elsewhere in the Pioneer River catchment, riparian vegetation is relatively degraded with the condition typically ranging from moderate to poor. Within the Pioneer River channel native vegetation is sporadic and weeds are widespread. The exception within the Pioneer River catchment is McGregor Creek which maintains excellent riparian vegetation condition within the entrenched macro-channel (Figure 31).

Figure 31. Excellent riparian vegetation within McGregor Creek which is significantly confined by terraces

Within the Bakers Creek sub-catchment riparian vegetation along the headwaters is in very poor condition. These streams are largely channelised through sugarcane plantations. Further downstream as the channel incises further into the terraces, riparian vegetation condition improves within the macro-channel and typically ranges from moderate to good with large isolated areas of inset floodplains retaining riparian forest.

Within the Sandy Creek sub-catchment riparian vegetation ranges from very poor to moderate in the upper reaches. Similar to Bakers Creek, riparian vegetation within the macro-channel improves as the system becomes more incised into the surrounding terraces. For the majority of the main stem of Sandy Creek riparian vegetation is in good condition.

Riparian vegetation condition within the Alligator Creek sub-catchment varies from poor to good. However, the majority of reaches are either in moderate or good condition. The best riparian vegetation is found in the middle reaches of the catchment.

Stability Channel stability within the Sandringham Bay receiving waters catchment is presented in Figure 35. The vast majority of reaches within the Sandringham Bay receiving waterways are either stable or experience only minor instabilities. The terraces which confine substantial lengths of waterways within the catchment limit significant lateral adjustment. The primary instability issues within the catchment occur in Upper Cattle Creek, Owen Creek (Figure 32) and a southern tributary of Sandy Creek.

Stream type assessment of the Mackay-Whitsundays region 34

Figure 32. Engineered Log Jams and revegetation have been used to limit bank erosion in Owen Creek

Physical form values Physical form values within the Pioneer River catchment have been significantly impacted by weirs, sand and gravel extraction and historical river improvement works. In the majority of reaches physical form values are very poor to poor. The Blacks Creek sub-catchment retains good physical form values and primarily consists of forested bedrock controlled streams (except for Teemburra Dam). McGregor Creek is the only other system in the Pioneer River catchment to retain good physical form values for most of its length.

Within Bakers Creek, Sandy Creek and Alligator Creek physical form condition is good in the mid reaches which are incised into the surrounding terraces. The incised form of these reaches provides protection from adjacent land use threats.

Sediment connectivity Both Teemburra Dam and Kinchant Dam are major barriers to sediment transport however both dams have small catchments. There are also three weirs (Marian Weir, Mirani Weir and Dumbleton Rocks Weir) on the Pioneer River which would act as barriers to sediment transport. However, in large flood events significant volumes of sediment stored behind weir pools is likely to be remobilised and transported towards Sandringham Bay.

Inset floodplains along the main stem of Bakers Creek, Sandy Creek and Alligator Creek, which are predominately forested, would act as buffers during flood events by capturing fine sediment.

Stream type assessment of the Mackay-Whitsundays region 35

Figure 33. Stream types within the Sandringham Bay receiving waters catchment

Stream type assessment of the Mackay-Whitsundays region 36

Figure 34. Riparian vegetation condition within the Sandringham Bay receiving waters catchment

Figure 35. Channel stability within the Sandringham Bay receiving waters catchment

Stream type assessment of the Mackay-Whitsundays region 37

4.5 Sarina Inlet

Overview Sarina Inlet is a small inlet directly to the south of Sandringham Bay. The receiving waters receive runoff from Plane Creek and Sarina beaches sub-catchments. The main streams in the Sarina beaches sub-catchment are Cabbage Tree Creek and Glasson Gully.

The majority of the receiving waters catchment is used for grazing. There are also substantial areas of the Plane Creek sub-catchment which are used for sugarcane cultivation.

Stream type assessment The stream types within the Sarina Inlet receiving waters are presented in Figure 38. Upper Plane Creek and its tributaries are either significantly confined or slightly confined by bedrock. Within the valley there are discontinuous floodplains and remnants of terraces. Downstream of Sarina bedrock confinement is reduced. The planform in lower Plane Creek is slightly confined by terraces with large areas of inset floodplains within the terrace confinement (Figure 36).

Directly to the north of Plane Creek, Cabbage Tree Creek drains a small hilly catchment. Cabbage Tree Creek is slightly confined by bedrock with the most extensive floodplain deposits located in the lower estuary. Glasson Gully in the very north of the Sarina beaches sub-catchment is also slightly confined by bedrock with a meandering planform in the estuary.

Figure 36. Lower Plane Creek which is slightly confined by terraces; through this section both banks abut inset floodplain units

Riparian vegetation condition Riparian vegetation condition within the Sarina Inlet receiving waters catchment is presented in Figure 39. Upstream of Sarina riparian vegetation is in poor or moderate condition. Often there is good coverage and diversity of native species however overall condition is impacted by weeds. In the lower estuarine reach riparian vegetation is in good condition with extensive mangrove coverage on inset features.

Upper Cabbage Tree Creek is in moderate condition as the riparian width is often quite narrow. The lower estuary has good riparian vegetation condition. Similarly, riparian vegetation in the Glasson Gully estuary is in good condition.

Stability Channel stability within the Sarina Inlet receiving waters catchment is presented in Figure 40 There are no significant channel stability issues within the catchment. The waterways are either stable or experience minor instabilities. The minor instabilities in the estuary reaches reflect normal rates of adjustment in meandering streams.

Physical form values Upstream of the estuary physical form condition within Plane Creek is either in moderate or poor condition. Instream values are often degraded due to online weirs or the significant weed infestation in some locations

Stream type assessment of the Mackay-Whitsundays region 38

(Figure 37). The lower estuarine reaches within the receiving waters catchment have good physical form values.

Figure 37. A section of Plane Creek which has significant weed infestation

Sediment connectivity There are two weirs on Plane Creek which would act as barriers to sediment transport. However, in large flood events significant volumes of sediment stored behind weir pools are likely to be remobilised and transported towards Sarina Inlet. The floodplain deposits along the upper to mid reaches of Plane Creek would provide some minor sediment buffering however they are rarely likely to be inundated. The most extensive sediment storages are likely to occur on the inset floodplains within the estuarine reaches.

Stream type assessment of the Mackay-Whitsundays region 39

Figure 38. Stream types across the Sarina Inlet receiving waters catchment

Stream type assessment of the Mackay-Whitsundays region 40

Figure 39. Riparian vegetation condition within the Sarina Inlet receiving waters catchment Figure 40. Channel stability within the within the Sarina Inlet receiving waters catchment

Stream type assessment of the Mackay-Whitsundays region 41

4.6 Ince Bay

Overview Ince Bay is located between Notch Point in the south and Freshwater Point in the north. The two sub- catchments which drain into the Ince Bay receiving waters are Rocky Dam Creek and Cape Creek. Within Rocky Dam Creek sub-catchment the main waterways are Rocky Dam Creek and a number of small northern waterways. Cape Creek sub-catchment consists of several small coastal waterways.

The primary land use within the Ince Bay receiving waters catchment is grazing and sugarcane production. There are also substantial areas of ponded pasture in the lower catchment of Rocky Dam Creek. Large areas of the upper Rocky Dam Creek catchment and the divide between Rocky Dam Creek and Cape Creek sub- catchment retain remnant forest.

Stream type assessment The stream types within the Ince Bay receiving waters are presented in Figure 43. The headwaters of Rocky Dam Creek are slightly confined by bedrock. Within the valley confines there are still extensive alluvial floodplain deposits. Through these reaches there are still significant bedrock controls within the streambed (Figure 41). Further downstream Rocky Dam Creek becomes more incised and is significantly confined by terraces. In some sections terrace confinement is reduced and there is more extensive inset floodplain development. Lower Rocky Dam Creek is unconfined with a meandering planform. Paleochannels indicate extensive historical planform adjustment including meander cutoffs.

Figure 41. Bedrock intrusion in Rocky Dam Creek

Tedlands Creek is a major tributary of Rocky Dam Creek. The upper reaches of Tedlands Creek are significantly confined by terraces before emerging into an unconfined wetland/floodplain system. Within the lower floodplain reach there is no defined channel. The lower area of the wetland zone has now been converted to ponded pasture.

The headwaters of Cherry Tree Creek, the northern tributary of Rocky Dam Creek, are slightly confined by bedrock. The mid reaches are slightly or significantly confined by terraces. The lower reaches are unconfined before draining into an extensive area of ponded pasture.

Within the Cape Creek sub-catchment the streams are significantly confined by bedrock in the upper catchment before flowing into the unconfined tidal zone.

Stream type assessment of the Mackay-Whitsundays region 42

Riparian vegetation condition Riparian vegetation condition within the Ince Bay receiving waters catchment is presented in Figure 44. Riparian vegetation condition is good throughout Rocky Dam Creek. Inset floodplains within the mid reaches maintain large areas of remnant riparian rainforest. The upper reach of Tedlands Creek also has good riparian vegetation and large areas of inset floodplains which maintain remnant forest. The lower reach has been impacted by ponded pasture.

The riparian vegetation condition within Cherry Tree Creek is variable. In the upper catchment condition is generally good, however there are also moderate and poor condition reaches. These reaches have typically been impacted by stock access (Figure 42). The lower reaches (upstream of the estuary) have been impacted by ponded pasture. The estuarine reach maintains good riparian vegetation.

Figure 42. Stock tracks impacting riparian vegetation condition within upper Cherry Tree Creek

Running Creek and Plum Tree Creek in the north of Rocky Dam Creek sub-catchment generally has good riparian vegetation. Similarly, riparian vegetation condition in the Cape Creek sub-catchment is good.

Stability Channel stability within the Ince Bay receiving waters catchment is presented in Figure 45. There are no significant stability issues within the catchment. Generally, waterways in the upper catchment are stable. The exception is a reach of upper Cherry Tree Creek which has minor instabilities due to stock impacts. The terraces confinement of Rocky Dam Creek limits significant lateral adjustment. The majority of channel instabilities within the receiving waters catchment are within the lower estuarine reaches which experience active meander migration. Lower Rocky Dam Creek is an actively migrating stream. Boat wash within these reaches may be exacerbating these processes.

Physical form values Physical form values are good across the majority of waterways within the Ince Bay receiving waters. Waterways typically have good riparian vegetation coverage and a diversity of instream habitats. The major impacts to physical form values are the ponded pasture land uses in lower Tedlands Creek and Cherry Tree Creek.

Sediment connectivity The major buffers to sediment transport through Rocky Dam Creek are likely to be the forested inset floodplains within the mid reaches. Both Tedlands Creek and Cherry Tree Creek have poor connectivity to Ince Bay due to alterations to the downstream coastal wetlands to form ponded pasture. The other smaller streams are well connected; some sediment storage would occur within the estuarine floodplains and tidal flats.

Stream type assessment of the Mackay-Whitsundays region 43

Figure 43. Stream types within the Ince Bay recieving waters catchment

Stream type assessment of the Mackay-Whitsundays region 44

Figure 44. Riparian vegetation within the Ince Bay recieving waters catchment Figure 45. Channel stability within the Ince Bay recieving waters catchment

Stream type assessment of the Mackay-Whitsundays region 45

4.7 Carmila Coast

Overview The Carmila Coast is a 50 kilometre stretch of coastline at the very southern end of the Mackay-Whitsundays region. A number of small easterly flowing streams drain into the Carmila Coast. From north to south these include the Marion Creek, Gillinbin Creek, West Hill Creek, Carmila Creek and Flaggy Rock Creek sub- catchments.

The major land use within the Carmila Coast receiving waters catchment is grazing. There are also significant areas which are used for sugarcane production on the alluvial plains in the mid to lower catchments. In the upper catchments of Marion Creek, Gillinbin Creek and West Hill Creek there are areas used for forestry production. The majority of the lower estuary zones are intact.

Stream type assessment The stream types within the Sarina Inlet receiving waters are presented in Figure 48. The upper reaches of Marion Creek, Gillinbin Creek, West Hill Creek, Carmila Creek and Flaggy Rock Creek all flow through valleys with varying degrees of bedrock confinement (Figure 46). This ranges from slightly confined to fully confined.

Near the Bruce Highway there are more extensive alluvial terrace deposits. All waterways are either slightly confined or significantly confined by terraces through this zone. In the lower reaches waterways become unconfined as more contemporary floodplain units are formed just upstream of, and within, the estuary.

Figure 46. Bedrock controls within Gillinbin Creek

Riparian vegetation condition Riparian vegetation within the Carmila Coast receiving waters catchment is presented in Figure 49. The majority of reaches within the Carmila Coast receiving waters catchment have good riparian vegetation condition. Gillinbin Creek has good riparian vegetation condition in all reaches within the sub-catchment. However riparian vegetation condition is degraded in the mid reaches of Marion Creek, West Hill Creek and Carmila Creek which ranges from poor to moderate condition. Riparian vegetation condition is most degraded within the Carmila Creek sub-catchment (Figure 47).

Stream type assessment of the Mackay-Whitsundays region 46

Figure 47. Riparian vegetation condition is poor in Carmila Creek near the Bruce Highway

Stability Channel stability within the Carmila Coast receiving waters catchment is presented in Figure 50. The most significant channel instabilities occur in West Hill Creek (just upstream of Bruce Highway) and within tributaries of Carmila Creek. Elsewhere only minor channel instabilities have been observed. The terraces confinement in the mid reaches limits any significant lateral adjustment.

Physical form values The physical form values are most degraded in Marion Creek, West Hill Creek and Carmila Creek. Significant lengths of stream have been impacted by weeds and stock access resulting in degraded riparian vegetation and instream habitat. Gillinbin Creek and Oaky Creek (within the Flaggy Rock Creek sub-catchment) have good physical form values along their entire length.

Sediment connectivity There are no major sediment barriers or buffers within the Carmila Coast receiving waters catchment. The major sediment storage within the catchment would occur within the lower floodplains and tidal flats.

Stream type assessment of the Mackay-Whitsundays region 47

Figure 48. Stream types within the Carmila Coast receiving waters catchment

Stream type assessment of the Mackay-Whitsundays region 48

Figure 49. Riparian vegetation condition within the Carmila Coast receiving waters catchment

Stream type assessment of the Mackay-Whitsundays region 49

Figure 50. Channel stability within the Carmila Coast receiving waters catchment

Stream type assessment of the Mackay-Whitsundays region 50

5 Summary

The stream type assessment of the Mackay-Whitsundays region identified a diversity of channel forms. The Mackay-Whitsundays region supports a range of land uses and many waterways across the region have been directly impacted by agricultural and urban developments since European settlement. However, despite these land use changes many of the waterways still retain excellent values which are important to both regional river health and GBRMP.

Waterways across the region are dominated by macro channel systems. These waterways are incised into the adjacent alluvial terraces and typically have a low width-depth ratio. The macro-channel systems resemble alluvial self-formed floodplain systems, however they typically behave differently. The terraces are rarely inundated and the terrace substrate (due to soil chemistry, cohesion or other reasons) are very resistant to both fluvial scour and mass failure processes.

The macro-channel morphology has a number of advantages for riparian vegetation communities compared to other agricultural floodplain systems across Australia. Riparian vegetation within the incised macro-channel can be retained without impacting on the adjacent floodplain land use. Across the region many of the macro- channel systems, particularly the smaller systems, maintain excellent riparian vegetation within the channel. However, many of the larger macro-channel systems, including Proserpine River, O’Connell River and Pioneer River have relatively degraded riparian vegetation (at least in part).

The macro-channel morphology across the Mackay-Whitsundays region significantly limits lateral channel erosion. Furthermore, vegetation within macro-channels further limits erosion of inset features. Channel erosion is most prevalent in reaches which are only slightly confined by either terraces or bedrock. Within these reaches contemporary floodplain deposits are more extensive. These deposits are typically more erodible than the terraces. The erosion primarily occurs in reaches with extensive inset floodplains and degraded riparian vegetation. This assessment has identified that major sediment loads from channel erosion are likely to be derived from:

• Upper Cattle Creek (Pioneer River catchment)

• Lower Owen Creek (Pioneer River catchment)

• O’Connell River where there are extensive inset floodplains

• St Helens Creek (Seaforth Coast receiving waters)

• The mid reaches of Murray Creek (Seaforth Coast receiving waters)

In many locations, typically where the floodplain area is smaller, inset floodplains retain remnant riparian communities. The best examples of forested inset floodplains occur in Sandy Creek, areas of Bakers Creek and Rocky Dam Creek. Within a macro-channel system these vegetated inset units are likely to capture significant volumes of fine sediment. As a result the management of inset units can play an important role in limited sediment loads to the GBRMP. This stream type assessment identified significant physical form values in many waterways. The streams across the region provide valuable habitat for many freshwater and marine species including species critical to the health of the Great Barrier Reef. Given the small coastal catchments, the Mackay-Whitsundays region presents excellent opportunities for system repair as in many cases isolated works (i.e. fish barrier removal, reach scale riparian restoration etc.) can substantially increase the connectivity and habitat availability from the coast to the headwaters.

Stream type assessment of the Mackay-Whitsundays region 51

6 References

Brierley, G.J. and Fryirs, K.A. 2005. Geomorphology and River Management: Applications of the River Styles Framework. Blackwell Publications, Oxford, UK

Brodie, J., Waterhouse, J., Schaffelke, B., Furnas, M., Maynard, J., Collier, C., Lewis, S., Warne, M., Fabricius, K., Devlin, M., McKenzie, L., Yorkston, H., Randall, L., Bennett, J. 2013. “Relative risks to the Great Barrier Reef from degraded water quality” in Synthesis of evidence to support the Reef Water Quality Scientific Consensus Statement 2013, Department of the Premier and Cabinet, Queensland Government, Brisbane.

Brooks, A.P., Olley, J., Iwashita, F., Spencer, J., McMahon, J., Curwen, G., Saxton., N. and S. Gibson. (2014) Reducing Sediment Pollution in Queensland Rivers: Towards the Development of a method to Quantify and Prioritise Bank Erosion in Queensland Rivers based on field evidence from the Upper Brisbane, O’Connell and Normanby Rivers. Final Report to Qld State Government, Department of Science Information Technology Innovation and the Arts, Griffith University, pp 76.

Gourlay and Hacker, 1986, Pioneer River Estuary Sedimentation Studies, Department of Civil Engineer, University of Queensland

Hacker, J.L.F, 1988, Rapid accumulation of fluvially derived sands and gravels in a tropical macrotidal estuary: the Pioneer River at Mackay, North Queensland, Australia, Sedimentary geology, Volume: 57 Issue: 3-4 Page: 299-315

Jupiter, S. and Marion, G., 2008, Changes in Forest Area Along Stream Networks in an Agricultural Catchment of the Great Barrier Reef Lagoon, Environmental Management, Vol. 42, pp. 66-79

Schumm, S. 1985: Patterns of alluvial rivers. Annual Review of Earth and Planetary Sciences 13, 5–27.

Stream type assessment of the Mackay-Whitsundays region 52

Attachment A Stream type assessment method

Stream type assessment of the Mackay-Whitsundays region 53

Stream type method The stream type assessment divided the channel assessment into a primary and inset channel assessment. This recognises that many rivers in the region do not necessarily have a ‘classic’ floodplain morphology and do not behave like true self-formed alluvial rivers. Many rivers in the region (and across Queensland) have a macro- channel bounded by resistant old floodplain/terrace deposits. Within the macro-channel an inset channel and a range of geomorphic units (e.g. bars, benches, islands, inset floodplains) can exist.

The larger main channel (or macro-channel) is referred to as the primary channel. Additional assessments were undertaken if there an inset channelexists. In many streams (particularly lower order streams and gullies) there will only be one channel.

The key components assessed as part of the stream type assessment of the Mackay-Whitsundays region are further discussed below. The GIS stream network has been produced which contains the below attributes for each reach. Field sheets for each site inspected have also been produced. The importance of each component and its reason for inclusion in the assessment is also outlined.

Primary channel assessment

Confinement Overview An alluvial channel can be confined (i.e. lateral adjustment of the channel is limited) by either:

• Bedrock valley margins

• Resistant terrace features (typically highly resistant silts and clays)

Alluvial channels can be confined to varying degrees by both terraces and bedrock valley margins. For this assessment the degree of lateral confinement was assessed as:

• Confined (>90 % of the channel abuts the confinement boundary (i.e. valley margin or terraces))

• Significantly confined (50% to 90 % of the channel abuts the confinement boundary)

• Slightly confined (10% to 50 % of the channel abuts the confinement boundary)

• Unconfined (<10 % of the channel abuts the confinement boundary) Importance The degree of confinement is an important boundary condition that controls the form of a channel. It can help determine the width of the zone in which the alluvial channel can migrate. This could help inform riparian management practices and the degree of lateral erosion.

Planform Channel planform is the shape of the river alignment in plan view. For this assessment planform was defined, based on Schumm (1985), as either:

• Straight (sinuosity 1 -1.05)

• Low sinuosity (1.06-1.30)

• Sinuous/meandering (1.31-3.0)

Importance The planform of the river can provide an initial indication of the mechanism and degree of alluvial channel adjustment (i.e. meander migration/extension, cutoffs etc.).

Lateral stability Lateral stability describes the degree of channel adjustment within the confinement boundary.. Lateral stability will be assessed using historical aerial imagery and classified as:

Stream type assessment of the Mackay-Whitsundays region 54

• Laterally stable (no observed lateral adjustment in recent times)

• Minor lateral instabilities (localised minor (less than 5 m or 10 % of channel boundary) channel width adjustment in last decade)

• Moderate lateral instabilities (widespread minor (less than 5 m or 10 % of channel boundary) channel width adjustment in last decade)

• Major lateral instabilities (greater than 5 m or 10 % of channel width adjustment of channel boundary in last decade) Importance The lateral stability of a river provides an indication of the rate and form of alluvial channel adjustment. This can help identify high risk zones and assist in determining appropriate riparian buffer zones to limit meander migration.

Avulsion risk Avulsions are a form of lateral instability that induces catastrophic adjustment to the river’s planform, creating a new section of river through abandonment of the existing river course. Avulsion risk will be assessed as:

• High – An avulsion is likely in the coming decades

• Moderate – An avulsion is possible in the coming decades

• Low - An avulsion is unlikely in the coming decades

Importance Understanding avulsion risk can by very important to informing floodplain and river management programs.

Note: Avulsion risk was classified as low across the Mackay-Whitsundays and is not discussed further

Riparian vegetation condition A higher level assessment of riparian vegetation condition was undertaken. For this assessment canopy cover is used as a surrogate for root reinforcement and hydraulic resistance along channel banks. The assessment utilised aerial imagery and field assessments and used a four tier rating system as outlined below:

• Good - Riparian zone typically has 90 -100 % woody vegetation canopy cover and riparian buffer width greater than 10 m

• Moderate - Riparian zone typically has greater than 70 % woody vegetation canopy cover however riparian buffer width is typically less than 5-10 m

• Poor - Degraded riparian zone with sporadic vegetation cover in the riparian zone - typically less than 70 % woody vegetation canopy cover

• Very Poor - Very degraded riparian zone with only isolated vegetation cover in the riparian zone - typically less than 20 % woody vegetation canopy cover

Importance Riparian vegetation is important for water quality, channel stability and terrestrial and aquatic habitat values. The extent and condition of riparian vegetation through a catchment can assist in prioritising riparian works.

Channel incision Channel incision occurs when the bed of the channel cuts down and causes reach-scale deepening of the channel. Deepening typically migrates in an upstream direction. The deepening is then normally followed by widening. If there is sufficient sediment supply from upstream then the widening may be followed by filling and channel contraction. Five stages of channel incision are shown conceptually in Figure 51.

If the channel network is susceptible to channel incision a stage of incision will be assigned. Where possible, the level of vertical control (i.e. underlying bedrock) will also be assigned as this can assist in determining the

Stream type assessment of the Mackay-Whitsundays region 55

level of incision. Many streams will not be susceptible to channel incision, such as confined reaches and macro- channel systems, and will not be assessed for a stage of incision.

Figure 51. Stages of channel incision

Importance Determining the phase of incision can greatly assist in waterway prioritisation. This can include identifying reaches in the waning stages of incision where low cost options may have a high likelihood of success for both river health and reducing sediment generation that will be exported to the coast. Furthermore, the length of unconfined reaches upstream of reaches in stage 2 (i.e. actively deepening) can assist in determining the trajectory of the incision process and prioritise management actions appropriately.

Note: Active channel incision was not identified within the third order and above streams within the Mackay-Whitsundays and is not discussed further

Inset channel assessment

Inset units The major geomorphic units within the primary channel including bars, benches, islands, and inset floodplains were also identified.

Importance Different inset units have different soil/sediment and morphologic characteristics which can impact on the sediment generation, transport and storage processes within the channel. An understanding of the units and their characteristics can inform management actions for different units (i.e. grazing practices, vegetation management etc.).

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Vegetation condition on inset units A higher level assessment of riparian vegetation condition on inset units will be undertaken. For each major inset unit (i.e. inset floodplains or benches), riparian vegetation condition was assessed using a four tier rating system as outlined below:

• Good - Unit typically has 100 % woody vegetation canopy cover or equivalent remnant standard cover

• Moderate - Unit typically has less than remnant but greater than 80%

• Poor - Unit typically has less than remnant and less than 80%

• Very Poor – Unit typically has less than remnant and less than 20% Importance Woody vegetation within the channel has been found to be a key variable that can control channel erosion in Queensland rivers (Brooks et. al. 2014). It can also play a major role improving the sediment trapping efficiency of inset units.

Stability of inset units The stability of major inset units was assessed. The higher level assessment was undertaken for all major inset units (i.e. inset floodplains or benches) using a four tier assessment:

• Stable (no observed adjustment of unit)

• Minor instabilities (less than 10 % of unit area adjustment in last decade)

• Moderate instabilities (less than 20 % of unit area adjustment in last decade)

• Major instabilities (greater 20 % of unit area adjustment in in last decade)

Importance Understanding the stability of inset units and their vegetation condition can help inform appropriate management of the units to increase their stability and sediment buffering capacity.

Overall channel stability The overall channel stability metric was determined based on the lower metric of either the stability of inset unit metric or the lateral stability metric.

Importance Helps compare channel instability issues at the regional scale regardless of whether the dominant process is a lateral adjustment of in-channel erosion.

Sediment regime and connectivity The sediment regime of each reach was assessed. The assessment identified whether the reach is a sediment source, transfer or accumulation zone. A higher-level catchment story of the sediment processes was undertaken for each major catchment.

A high level assessment of the downstream sediment buffers (floodplains, channels, alluvial fans, terraces, and trapped tributary fills) and barriers (reservoirs and weirs) was undertaken to determine the reach sediment transport connectivity to the GBR lagoon. The GBRMA Blue Maps were also used to inform this process. The assessment of sediment connectivity used a four tier system:

• Highly connected – No barriers and downstream channel capacity is sufficiently high that there is infrequent activation of sediment buffers (i.e. greater than 5 years ARI as a guide)

• Moderately connected - No major barriers (may include minor weirs) and there is relatively frequent activation of sediment buffers (i.e. between 2-5 years ARI as a guide)

• Poorly connected - Major barriers or there is frequent activation of sediment buffers (i.e. occurs during most flow events)

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• Very poorly connected – Major barriers and buffers such that there is no defined channel connecting to the ocean. Importance Understanding how connected a reach is to the GBR lagoon in terms of sediment delivery can assist in planning sediment management programs.

Instream habitat A higher level assessment of instream habitat was undertaken during the field inspections. The assessment used a four tier system as set out below:

• Good – The assemblage of geomorphic units is appropriate for that stream type and the units are intact and provide good physical form (including large wood and vegetation coverage) and hydraulic habitat resulting in high potential for ecological diversity appropriate for that stream type (i.e. similar to the pre-development intact state).

• Moderate - The assemblage of geomorphic units is appropriate for that stream type however there is some degradation of the units resulting in patchy physical form (including large wood and vegetation coverage) and hydraulic habitat providing moderate potential for ecological diversity appropriate for that stream type.

• Poor – The assemblage of geomorphic units for that stream type has been degraded resulting in poor physical form (including large wood and vegetation coverage) and hydraulic habitat providing poor potential for ecological diversity appropriate for that stream type.

• Very Poor – The assemblage of geomorphic units for that stream type has been degraded resulting in an actively degrading stream (i.e. bed aggradation/degradation) with very poor physical form (including large wood and vegetation coverage) and hydraulic habitat providing very poor potential for ecological diversity appropriate for that stream type.

Importance Helps understand the potential for aquatic ecological diversity within the reach to inform waterway prioritisation.

Physical form condition The overall physical form condition was assessed based on the riparian vegetation condition assessment and instream habitat assessment. The matrix below was used for the assessment.

Riparian vegetation condition Good Moderate Poor Very Poor

Good Good Good Moderate Poor

Moderate Good Moderate Poor Poor

Poor Moderate Poor Poor Very Poor

habitat

nstream nstream I Very Poor Poor Poor Very Poor Very Poor

Importance The higher level assessment of physical form condition helps understand the potential for both aquatic and terrestrial ecological diversity within the reach to inform waterway prioritisation.

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