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March 2017 Issued to Chris Dench (Reef Catchments) Description: Draft for comment Citation: Draft for comment - please do not cite.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 Stream type assessment of the Mackay-Whitsundays region i 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 Stream type assessment of the Mackay-Whitsundays region ii 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 Stream type assessment of the Mackay-Whitsundays region iii 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