Mulgrave River Management Action Plan

Document Control Summary

Natural Resource Assessments Pty Ltd

Job No: F:\AAA\228-Cairns River Improvement Trust\ 228002\Reports\MulgraveRiver_MAP_Final.R01.doc Status: Final Project Manager: Tim Anderson Title: Mulgrave River Management Action Plan Author/s: Dr Alexander Herr, Dr Jon Nott, Stuart Worboys, Marc Seifert, Alison Darroch, Anne Bolton, Tim Anderson. Client: Cairns River Improvement Trust Client Contact: Rob Lait Date of Issue: 24 May 2001 No. of Copies: 2 client, 1 master, 1 file/library Dispatched Via: Hand delivery Delivery Format: Hardcopy Other Info or Nil Requirements:

Quality Assurance

Approved for Issue Document Author Technical Review Editor by QA Manager Version Date Signature Dr Alexander Herr Tim Anderson Alison Darroch Final 24/5/01 PhD, Diplom (MSc MAgrSc MA BA equivalent) BAgrSc (Hons) Ross Kapitzke M NatRes BE (Hons)

Table of Contents

1. Introduction ...... 1 1.1 Background...... 2

2. Study Team...... 3

3. The Mulgrave River Catchment ...... 4 3.1 Vegetation...... 4 3.2 Soils...... 8 3.3 Water Quality ...... 8 3.4 Conservation and Biodiversity...... 9

4. Approach...... 10

5. Identification of Issues (Stage 1) ...... 12 5.1 Community Consultation...... 12 5.2 Cultural Issues...... 15

6. Geomorphological Assessment (Stage 3)...... 17

7. Field studies (Stage 4) ...... 23

8. Mulgrave River Draft Management Action Plan (Stage 4) ...... 25 8.1 Reach Prioritisation...... 25 8.2 Results ...... 26

9. Implementation...... 30 9.1 Strategies ...... 30 9.2 Work Specific Recommendations...... 32

10. Bibliography...... 34

Figures

Figure 1: Location of Reach Sections...... 5 Figure 2: Five Year Running Mean of Maximum Monthly Instantaneous Flood Discharges on the Mulgrave River for the Years 1916 – 1999 ...... 18

Tables

Table 1: Summary of Issues as Identified from the Desktop Study and the Public Meeting of Stakeholders...... 14 Table 2: Summary Table of Issue Ratings as Determined by Field Assessment...... 27 Table 3: Matrix of Reaches Ordered According to Four Prioritisation Rules...... 29 Appendices

Appendix 1: Theoretical Context for the Study Approach Appendix 2: Example Proforma Reach Assessment Sheets Appendix 3: Letter from EPA (Cultural Heritage) Appendix 4: Geomorphological Study of the Mulgrave River - Dr J. Nott Appendix 5: Reach Descriptions and Site-specific Sketches Appendix 6: Table of Plates

Attachments

Attachment 1: CD containing: Site-specific Photographs and EPBC Database Search Results Mulgrave River Management Action Plan

1. Introduction

NRA was commissioned by the Cairns River Improvement Trust (CRIT) and the Mulgrave River Working Group (MRWG) to prepare the Mulgrave River Management Action Plan (MRMAP). The purpose of this work is to devise a management plan outlining priorities for site remediation works along the Mulgrave River.

The study draws on recent information and research undertaken in the catchment, which identified: · areas in need of repair · actions to improve the river’s health · integrate resource use with ecological integrity of the catchment (NQ Joint Board 1998, RMCCC 1997), while also addressing community concerns.

The approach taken in this study relies on expert knowledge, drawn from a multi-disciplinary team utilising existing information. A long-term scientific study could describe and quantitatively analyse changes in the river and identify causes, however, it is arguably not the most practical means of satisfying the goals of the Strategic Plan of the Russell and Mulgrave Rivers (RMCCC 1997) and the Mulgrave-Russell Catchment Rehabilitation Plan (NQ Joint Board 1998), which are specifically to develop an action plan for the Mulgrave River. The approach includes prioritisation of issues and sites for remediation, and relies on visual rapid assessment and incorporation of contemporary community perceptions.

This study focuses on the Mulgrave River and its tributaries as outlined in the brief, however it is imperative that river rehabilitation takes into account the landscape perspective. In this report, where feasible, measures incorporating the wider landscape (ie more than the immediate area of the river with its channel and high banks) have been suggested. Such measures include provision of habitat connectivity and ecosystem functionality, which will in turn maintain sustainability of the landscape.

The report provides a prioritisation matrix for site rehabilitation that maximises sustainable management of the Mulgrave River. It also provides a basis for funding submissions for future works and for monitoring and evaluation of remediation works.

This report documents the stages of the project and includes descriptions of the: · biophysical setting · approach · identification of issues · a geomorphological assessment of the river · field studies · Mulgrave River Draft Management Action Plan · actions, priorities, and costs for implementation of works.

Natural Resource Assessments Pty Ltd 1 24 May 2001 Mulgrave River Management Action Plan

1.1 Background

There is a considerable amount of literature concerned with land use, and prevailing biophysical and ecological conditions in the Mulgrave catchment. Literature consulted for this study is referenced in the bibliography in Section 10 of this report. A brief chronological overview of key previous natural and cultural resources studies of the Mulgrave River catchment follows.

· In the early 1980’s Cassells outlined land use priorities for the Mulgrave River including determination of conservation areas. One main area of concern was the loss of riparian vegetation along the Mulgrave River. · An agricultural study classified landforms and associated soils as to their suitability for sugar cane production in the Mulgrave area (Holz 1985). · An overview study summarising the biophysical environment, land use and cultural aspects of the Mulgrave and Russell catchments was conducted to provide a basis for land use planning (Connell Wagner 1992). This study, commissioned by the Water Resources Commission and the Mulgrave River Improvement Trust (MRIT), collated for the first time values, issues and conflicts as perceived by the community of the Mulgrave Catchment.

· Following on from the above work the strategic plan for the Russell and Mulgrave rivers was developed, this identifies nine issues of concern. The three highest ranking issues are: - decreased water quality - decreased stream and riparian habitat values - loss of stream aesthetic and recreational values (RMCCC 1997). · In 1998 the NQ Joint Board prepared a report describing rehabilitation priorities for the Russell – Mulgrave Rivers (NQ Joint Board, 1998).

Natural Resource Assessments Pty Ltd 2 24 May 2001 Mulgrave River Management Action Plan

2. Study Team

A multi-disciplinary team lead by NRA was brought together to prepare the MRMAP. Members of the team and their fields of specialisation are listed below:

· Tim Anderson (Project Director) – Catchment Management

· Dr Jonathan Nott – Geomorphology

· Ross Kapitzke – Environmental Engineering

· Alan Dunne – River Engineering

· Dr Alexander Herr– Terrestrial Ecology

· Marc Seifert – Freshwater Ecology

· Stuart Worboys – Riparian Vegetation

· Anne Meiklejohn – Cultural Heritage

· Ryan Beales – GIS.

The technical team was assisted by a number of individual landholders and/or members of the Mulgrave River Working Group and Cairns River Improvement Trust. This assistance, which is gratefully acknowledged, was provided during the planning, field and reporting phases of the study and significantly contributed to the value of this final report.

Natural Resource Assessments Pty Ltd 3 24 May 2001 Mulgrave River Management Action Plan

3. The Mulgrave River Catchment

The Mulgrave River rises in the Lamb and Bellenden Ker Ranges and flows through a well- defined valley before crossing a narrow coastal plain and being turned south by the Malbon Thompson Range to Mutchero Inlet and the sea. The catchment area comprises 810 km2 with two major tributaries being the Little Mulgrave and Behana Creek (the latter is not within the scope of this study). The mean annual discharge is calculated to be 770,000 ML (Russell et al 1996). The study area is shown on Figure 1.

3.1 Vegetation

The high peaks of Bellenden Ker experience consistently high rainfall, and their associated forests have consequently remained relatively unaffected by long-term climatic change (Truswell 1990, Webb and Tracey, 1981). They provide refugial areas of biota from the wet forests of Australia’s past, and possible refuges for species that may be impacted by future climatic changes. Much of this rainforest area is protected within the Wet Tropics World Heritage Area. Rare and Threatened species restricted primarily to the Bellenden Ker/Bartle Frere area include Linospadix palmeriana (Walking Stick Palm), Trichomanes exiguum (Filmy Fern) Plectranthus gratus, and Hollandaea sayeriana (Sayer’s Silky Oak). Rare species likely to occur in the study area, based on habitat preferences, include Myrmecodia bercarii (Ant Plant), Pseuduvaria mulgraveana, and Macaranga polyadenia.

Within the study area, much of the land has been cleared for agriculture, primarily sugar cane. Remnant vegetation occurs on steeper gradients, along creek banks and in poorly drained low- lying areas. These remnants are frequently subject to weed invasion and ongoing clearing (NQ Joint Board 1998). Nevertheless, such remnant vegetation represents important fragments of several rare lowland vegetation communities, and provides important links between the forests of the Malbon Thompson Range and the Bellenden Ker Range.

Upstream of the Bruce Highway bridge, lower rainfall areas lying in the rain-shadow of the Bellenden Ker Range support a forest community dominated by Eucalyptus tereticornis (Forest Red Gum), often with a rainforest understorey. This community corresponds to the Regional Ecosystem1 (RE) number 7.11.18 (Forest Red Gum (Eucalyptus tereticornis) woodland on wet to moist metamorphic foothills). Along the river banks, the Endangered RE 7.3.22 (complex mesophyll riparian vine forest on moist and dry well drained lowland alluvial levees) is the most extensive vegetation community between the Little Mulgrave and the Bruce Highway bridge, with instances of the Endangered RE 7.3.28 (riparian herbfield/shrubland on river and stream bed alluvia) on sandbars along the river’s length.

1 Regional Ecosystems are described in Sattler and Williams (1999) and their conservation status is listed in the Queensland Vegetation Management Regulation 2000.

Natural Resource Assessments Pty Ltd 4 24 May 2001 Mulgrave River Management Action Plan

Figure 1: Location of Reach Sections

Natural Resource Assessments Pty Ltd 5 24 May 2001

Mulgrave River Management Action Plan

Downstream of the Bruce Highway the land becomes flatter and less well drained. The remnant vegetation is much more fragmented. Along the riverbanks remnant vegetation fragments larger than 10 ha are rare. Vegetation communities are often dominated by species characteristic of poorly drained areas – Archonthophoenix alexandrae (Alexandra Palm), various Melaleuca (Paperbarks) and Barringtonia racemosa (Freshwater Mangrove). These remnants reflect once extensive areas of lowland mesophyll vine forest, now a rare vegetation community on the coastal plain. Lagoons and wetlands are common. Retention of local hydrological regimes is essential to maintain the integrity of these communities.

Remnant vegetation communities along the lower reaches of the river include RE 7.3.3 (Alexandra Palm (Archonthophoenix alexandrae) swamp vine forest on wet poorly drained fertile lowlands), a rainforest ecosystem dominated by Alexandra Palms, RE 7.3.6 (Swamp Paperbark (Melaleuca quinquenervia) open forest/vine forest complex on a variety of very wet poorly drained lowlands), a complex swamp community generally dominated by Paperbarks, and RE 7.3.10 (complex mesophyll vine forest on very wet well drained fertile lowland alluvial soils), a well-developed rainforest community. Many of these communities have been invaded by Annona glabra (Pond Apple). All three of these REs are currently considered endangered. Downstream toward the mouth, the mangrove community 7.1.1 (Mangrove forests on coastal lowland saline alluvial soils) lines both banks of the river.

Fishery Creek and Hobson’s Creek (Figure 1) have been channelised in their lower reaches to improve drainage of nearby cane paddocks. Much of their associated vegetation has been cleared, although in some cases reinstatement of vegetation for the purposes of bank stabilisation has been carried out. Vegetation along Figtree Creek is almost continuous. Despite infestations of Pond Apple and Thunbergia, this vegetated corridor provides a key habitat link between the Bellenden Ker Range and the River. Further to the north, Behana Creek provides a similar vegetated link between the Range and the river.

The highly mobile substrate and extremes of flow limit aquatic plant growth to lagoons, and reaches or tributaries with consistent flow. Algae are the dominant primary producers in reaches of the Mulgrave where they are not limited by shade. Tanner’s Lagoon, a sheltered backwater linked to the river by a narrow channel, has a high diversity of aquatic plants, and would act as a seeding source for downstream reaches. The rare species Torrenticola queenslandica has been recorded from the upper reaches of the river and it’s tributaries. The rare submerged aquatic plant Vallisneria nana is known to occur in the Russell River, and is likely to occur in the lower reaches of the Mulgrave.

Weeds are a major problem within the Russell-Mulgrave Catchment, impacting severely on biodiversity and function of the catchment (NQ Joint Board 1998). The ecological and socio- economic significance of weeds was reaffirmed in the course of this current study.

The imperative to manage pests was recognised by the Cairns City Council in a Pest Management Plan initiated in 1997 (Cairns City Council, 1999). Parts of the Mulgrave River are identified as being infested with Blue Trumpet Vine (Thunbergia grandiflora and T. lurifolia), Cucumber Tree (Palmentaria edulis), Sicklepod (Senna obtusifolia), Leucaeana (Leucaena leucocephala), Para grass (Brachiaria mutica), Pond Apple (Annona glabira), Elephant Grass (Pennesetum purpureum), and others. The upstream sections of the Mulgrave are particular problem zones for Thunbergia and Leucaeana.

The current Pest Management Plan (Cairns City Council, 1999), prepared through a consultative process, lists prioritised key pests and presents a detailed management response (strategies, objectives, actions and resource requirements).

Natural Resource Assessments Pty Ltd 7 24 May 2001 Mulgrave River Management Action Plan

3.2 Soils

Soils in the catchment are determined by the parent rock, their erosion and rainfall, yielding seven major soil categories (NQ Joint Board 1998): 1. Soils derived from acidic igneous rocks (mainly granite). 2. Soils derived from non-acidic igneous rocks (mostly basalt). 3. Soils of metamorphic rock origin. 4. Well drained alluvial soils. 5. Poorly drained alluvial soils. 6. Soils originating from the pediments and beach ridges of the floodplain and coast. 7. Soils from estuaries.

Details regarding the management of these soils can be found in NQ Joint Board (1998), and in Section 6.1 Geomorphological Assessment of this report.

3.3 Water Quality

In the past, indicators of decreased water quality have been published for the Mulgrave River. The river’s high nutrient load, the second highest (after the Johnstone River) in nitrogen and phosphorous concentrations in Queensland, may be attributed to high run off rates (Moss et al 1992). Recorded high ammonium and nitrate levels found in the river may also be attributed to the Gordonvale sewage treatment plant effluent and intensive agriculture (Russell et al 1996). Monitoring data collected by Cairns City Council, and reported to the Environmental Protection Agency, indicates that discharge from the sewage plant is within licence requirements (pers. comm. Bruce Jennings, CCC, 23 May 2001). Adjacent to the Mutchero Inlet National Park low pH levels have been detected, and may be caused by the acid sulphate soils of the nearby swamps (Russell et al 1996). Despite the lower part of the Mulgrave catchment being intensively used for cane production, pesticide contamination and salinity has been recorded as low (NQ Joint Board 1998). Recent sedimentation related to land uses has been identified as a major issue in the lower part of catchment. Urbanisation is a further issue as are localised temperature increases due to Mulgrave Sugar Mill’s discharge of cooling water (NQ Joint Board 1998). The mill has worked towards amelioration of this issue through installation and operation of a system of cooling ponds (pers. comm. Kurt Derbyshire QDPI, 18 May 2001). Information on groundwater quality is sparse, but one study attributed increased nitrate concentrations to the use of fertilisers (Hausler 1990).

In the State of the Environment Report released earlier this year (EPA 1999) it is concluded that most scientists acknowledge that nutrient and sediment inputs to coastal waters have increased substantially as a result of human activity, the significance of this increase is largely unknown. The absence of baseline data and/or sufficient historic data sets and a severely limited sample size are major impediments to scientific certainty. The Testing the Waters report (DEH & DPI, 1999) is the most comprehensive recent publication on the quality of Queensland’s water. It was prepared using data from 480 sites covering the period of 1992 – 1996. The report acknowledges the limitations of simply summarising water quality conditions across the State. It states the generality that, while a significant proportion of sample sites reflect good water quality conditions, there are also a large number that indicate slightly impacted conditions, and only relatively few are indicative of poor quality conditions.

Natural Resource Assessments Pty Ltd 8 24 May 2001 Mulgrave River Management Action Plan

Waterwatch has been monitoring various points on the Mulgrave River and its tributaries since 1996. Nitrate levels for the Mulgrave River have increased over time and with distance downstream, and more recently, high nitrate levels have been identified in Mackey’s and O’Leary’s Creeks (pers. comm. Nicola Wright, QDMRM, 22 May 2001).

The impacts associated with degradation of natural systems by European anthropogenic activities may not all be quantifiable. In terms of water quality, this appears to be the case. It is however beyond dispute that natural systems have degraded.

3.4 Conservation and Biodiversity

The catchment is a regional node for endemic primitive flowering plants including Stockwellia, the Eucalyptus precursor (NQ Joint Board 1998), and the endangered Torrenticola queenslandica (a small moss-like plant attached to rocks in fast flowing streams of the upper- catchment and found in Little Mulgrave). A range of endangered animals (including mammals, reptiles, frogs and fish) are also known to occur in the catchment area.

A total of 22 species of conservation concern are known to occur in the study area. This was determined through a search of the Environment Australia database, which lists all species protected by the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act), together with maps showing species’ distribution. Species listed in this act are of national significance. The results of the EPBC database search conducted during this study are presented on the accompanying CD. Although some of the species listed are marine, their environment is influenced by water flowing into the sea from the Mulgrave River.

Natural Resource Assessments Pty Ltd 9 24 May 2001 Mulgrave River Management Action Plan

4. Approach

The approach taken in this project delivers a document that outlines a reach-specific action plan for the sustainable management of the Mulgrave River. It is based on an holistic assessment that includes ecological, geomorphological, cultural and engineering information and incorporates information about community and stakeholder perceptions.

Broad issues relating to the sustainable management of the Mulgrave on the regional and catchment scales were identified in the RMCCC (1997) and, NQ Joint Board (1998). Russell et al (1996) also identified management strategies for improvement of instream habitat for fish on the catchment basis. All of these studies focussed on the broader scale and the River Management Action Plan draws on this information.

The River Management Action Plan provides: · prioritised remediation works · indicative cost estimates for works · schematic drawings of proposed engineering works where appropriate.

The work is based on a combination of the methodologies outlined in Stream Stabilisation for Rehabilitation in North Queensland (Kapitzke et al 1998) and A Rehabilitation Manual for Australian Streams (Rutherford et al 1999). Kaptizke et al’s (1998) steps 1-5 were followed for the concept phase investigations at the site scale and adapted to the catchment and reach scale. This ecological approach was supplemented by multiple stream management objectives as outlined in Steps 4-8 of Rutherford et al (1999). Details of this approach can be found in Appendix 1. This process allowed for site-specific remediation measures to be prioritised.

The work was conducted in four stages. Each of the stages relied on information collected and analysed during the former stage. Stage 1: Identification of initial issues. Issues relating to the Mulgrave River catchment were initially identified through a review of existing information and a public meeting and were based on existing catchment and reach level information. Stage 2: Desktop study. This combined the information collated from Stage 1 with a detailed geomorphological assessment of the stream carried out using aerial photography and site inspections. This assessment identified stream processes and classified the river into geomorphological sections. Field proformas were developed and the geomorphological classification was overlain with ecological/infrastructure information to identify reaches and particular sites for field assessment and reporting. Stage 3: Field assessment. Firstly, a project team consisting of an ecologist and an engineer assessed specific sites (predetermined through landholder consultation). Secondly, a reach assessment was undertaken by a geomorphologist, botanist, limnologist, terrestrial ecologist, and river engineering expert; assisted by members of the Mulgrave River Working Group. Field proformas were completed and sketches of specific sites were made. Causes or potential causes of the existing and emerging problems at specific sites were identified through this field work and are presented in Appendix 2 – Proforma Reach Assessment Sheets.

Stage 4: Draft Management Action Plan. Together with the synthesis of Stages 1 to 3, the preparation of the Draft Plan entailed – identifying possible restoration works

Natural Resource Assessments Pty Ltd 10 24 May 2001 Mulgrave River Management Action Plan

– rating environmental issues for each reach – prioritising works based on field assessment outcomes. The Draft Management Action Plan was submitted on 2 April 2001. Stage 5: Presentation workshop and review of Draft Plan by CRIT, MRWG, and stakeholders for comments. A synopsis of the Draft Management Action Plan was presented at a workshop with the MRWG on 24 April 2001, and then at a separate meeting that day, to the Mulgrave Landcare and Catchment Group Incorporated. During the period from 2 April to 3 May 2001 an additional 28 copies of the Draft Management Action Plan were distributed in response to requests. In addition to comments noted during the workshops, comments were either collated and forwarded by the MRWG (correspondence received 16 May 2001), or made direct to NRA in both written and verbal form (communications received 24 April 2001, 2 May 2001, 17 May 2001, 18 May 2001). Stage 6: Submission of final plan after assessment and incorporation of comments from stage 5.

Natural Resource Assessments Pty Ltd 11 24 May 2001 Mulgrave River Management Action Plan

5. Identification of Issues (Stage 1)

The Russell Mulgrave Catchment Coordination Committee (RMCCC 1997) identified nine issues of concern. The three highest ranking issues were decreased water quality, decreased stream and riparian habitat values, and loss of stream aesthetic and recreational values. Weeds, water quality, and coastal wetland habitat loss are identified as being of high concern by the NQ Joint Board (1998). Riverbank erosion, erosion control potential, and habitat connectivity between the Malbon Thompson Range and Bellenden Ker foothills are identified as priorities for rehabilitation in the Mulgrave River in the FNQ Regional Plan – Supporting Technical Document – Environment (FNQ RPAC, 2000).

The Mulgrave River was found to have the second highest (after the Johnstone River) nitrogen and phosphorous loads in Queensland due to high run off rates (Moss et al 1992). Such high run off rates are an indication of low catchment water retention, which may be related to clearing vegetation and altering the natural drainage network of the lower Mulgrave (Connell Wagner 1992). NQ Joint Board (1998) also noted that bank erosion along the river is evident and may lead to channel migration, which in turn can result in slumping of riverbanks and loss of agricultural land. Sedimentation is evident in the lower reaches of the river. Pondage occurs within the swamps and cane fields on former swamp land (NQ Joint Board 1998) and flooding may result in loss of crops through inundation of crops.

Water extraction (132500 ML/a) from the Mulgrave groundwater system is also of concern (NQ Joint Board 1998) as it may lead to wetland salinisation and salt wedge intrusion upstream of the lower reaches of the Mulgrave (Hausler 1991). The riparian vegetation along the lower Mulgrave River has mostly been replaced by cane farming; although some intact riparian zones exist, and tree planting in combination with structural works has been conducted in some parts. Overuse of some recreational areas and encroaching urbanisation contributes to the loss of recreational values of the river. Loss of fish habitat and fish numbers may be attributed to water quality issues (Russell et al 1996).

5.1 Community Consultation

A public meeting involving CRIT/MRWG and stakeholders (including EPA, DPI, DNR, Water Watch, landowners) was held on the 1 March 2001 from 18:00-20:30 at the Gordonvale RSL.

The purpose of this meeting was to: · inform stakeholders of the approach to the study · identify issues seen as important by the community (incorporated into Table 1) · seek endorsement for the proposed approach.

Natural Resource Assessments Pty Ltd 12 24 May 2001 Mulgrave River Management Action Plan

The following issues were raised during the meeting: · Water quality problems are suspected by some community members to occur below the Gordonvale Tip. The tip is now a transfer station, however refuse material remains on- site. A visual inspection of Crooked Creek (Tributary of Behana Creek) during high flows, has revealed foaming. (State Government departments report that groundwater flows are huge and that no groundwater quality problems have been recorded (pers. comm. Tony McCormack CCC 24 April 2001). There are no human point source impacts on groundwater from activities such as sewage disposal, land fills, or contamination from industry (DEH and DPI 1999)). Waterwatch, which has undertaken monitoring on the River, may focus some of its attention on this stream to ascertain more details. Behana Creek was not identified as an area of high priority for rehabilitation in the NQ Joint Board report (1998); and this creek and its tributaries are not considered by this MRMAP due to resource constraints. · The Mulgrave Mill has undertaken its own water quality studies since 1968. Water quality is not considered a problem, however there is a temperature increase in the receiving waters and one organic substance has been identified, but the source can not be pinpointed and may be already present above the Mill. · One additional field day was suggested by the stakeholders, during which Jon Nott, Alan Dunne and Marc Seifert were to investigate specific sites identified by the stakeholders; in order to ascertain anthropogenic influences in relation to erosion, and to determine the success or failure of former remediation works. This was seen as important by the stakeholders and as a result one additional field day was incorporated so that these former works could be visually assessed. Rob Lait (Chairman, CRIT) indicated that a document is being prepared on past river works undertaken by the CRIT. This may be made available to NRA, should it be completed in time. · Deeral Landing is used intensively by larger boats and speedboats. Passage of these boats is causing bank erosion through wave action. It may be worthwhile creating a landing structure further downstream, which can then be used by the heaver boats, thus reducing the impact of wave action. · The water diversion from a subdivision at Hemmings Creek results in larger amounts of water being released during the wet season, causing additional erosion. A site for investigation would be the original Gordonvale tip west of the Bruce Highway (at Leonie’s shed) and west of the diversion channel taking water from O’Leary’s creek catchment and flows into Hemmings Creek (pers. comm. Vince Reghenzani, 6 May 2001). · There was concern about the slow response from government organisations towards supporting and financing community actions. It was also felt that obtaining data held by government was difficult and slow unless paid for.

The meeting endorsed NRA’s approach to assessing the river using a team of specialists and developing a priority list of restoration actions. The process of prioritisation was to be documented and transparent (Section 8).

A summary of the issues identified through the desktop study and from the community consultation meeting is provided in Table 1.

Natural Resource Assessments Pty Ltd 13 24 May 2001 Mulgrave River Management Action Plan

Table 1: Summary of Issues as Identified from the Desktop Study and the Public Meeting of Stakeholders

Category (after Kapitzke Issue Details 1999b) Amenity/Cultural Tourism/ – overuse (poor management) of riparian and Recreation swimming areas – boating intensity near Deeral Landing Flood/ erosion Erosion – cropping/grazing to streambank – extraction industry and other removal of sand/gravel – former infrastructure remediation works Flood/ erosion Flood control – widening, disengaging, levee banks in conflict with habitat restoration, on the spot remediation not taking into account the whole system – gravel extraction, agricultural drainage system in canelands Flood/ erosion Sediment – although used as spot mitigation it causes (Gravel) water regime changes, downstream erosion extraction – reduces aesthetic values for tourism Flood/ Sedimentation Sedimentation – sediment aggradation in the lower Mulgrave. – weed infestation of point bars – gravel extraction in upper Mulgrave returned sand to the stream – sedimentation has a major impact in reducing the diversity of aquatic habitats, particularly pool-riffle sequences, which provide fish habitat. Habitat/ Conservation – coastal communities (Mutchero Inlet National Conservation Park) threatened by changes in hydrology (eg draining) – cassowary habitat in swamps Habitat/ Feral animals – threaten native species eg cassowaries by Conservation dogs, frogs by cats, native fish by exotics – harbor diseases Habitat/ Threatened – habitat loss in general, water quality for Conservation species amphibians and other water-dependent organisms – crocodiles, fish, frogs, Cassowaries, Beach Thicknee, Little Tern, Great Crested Grebe, Black-necked Storck, Cotton Pygmy-Goose, Painted Snipe and Eastern Curlew, bats (four species), Tiger quoll, three Ringtail possums, Tree-kangaroo, Musky Rat Kangaroo Habitat/ Weeds – threaten: riparian habitats & restoration efforts Conservation – choke waterways (eg para grass) – should be controlled on farm land and public land

Natural Resource Assessments Pty Ltd 14 24 May 2001 Mulgrave River Management Action Plan

Category (after Kapitzke Issue Details 1999b) Water quality Gordonvale tip – no surface or groundwater run off control, CCC has indicated that control measures are in place, water quality is monitored quarterly, and he tip received no heavy industry refuse (pers. comm. Tony McCormack, CCC, 24 April 2001) – potential input of chemicals/oils into Mulgrave via Crooked Creek, a tributary of Behana Creek. Water quality Gordonvale – secondary treated sewage is released into the sewage effluent Mulgrave River Water quality Eutrophication/ – sewage, fertiliser & pesticide input (high nitrate algae growth, and sulfate) into groundwater and Mulgrave pesticides River. – fish Water quality Mulgrave Mill – instream habitat & fish effluent and – eutrophication cooling water Water quality Salinisation – change of natural flow regime (drainage channels, dams, water extraction) Water quality Urban – increased traffic - risk of chemical spillage Habitat/ development – destruction of riparian and instream habitat Conservation (Gordonvale) – surface sealing (leads to decreased retention Flood/ Erosion time of rainfall) and grey water run off affects Amenity/cultural instream habitat and water quality – increased water extraction (drinking, household, and industrial water ) Water quality Waterborn – sewage input from Gordonvale and private diseases sewage systems

5.2 Cultural Issues

This section draws together conclusions and recommendations relating to cultural heritage as cited in previous studies of the area. The Queensland Environmental Protection Agency (QEPA) was also consulted for advice on cultural heritage issues relating to the study area.

It is a legislative requirement that cultural heritage places are protected and managed for current and future generations. All items of cultural heritage in Queensland that can be identified as an ‘item of the Queensland Estate’, are protected under the provisions of the Cultural Record (Landscapes Queensland and Queensland Estate) Act 1987. ‘Queensland Estate’ means evidence of human occupation of the areas comprising Queensland at any time that is at least 30 years in the past but does not include anything: · made or constructed as a facsimile; or · made or constructed at or after the commencement of this Act for the purpose of sale; or · that is not of prehistoric or historic significance.

Natural Resource Assessments Pty Ltd 15 24 May 2001 Mulgrave River Management Action Plan

An “Item of the Queensland Estate” includes any structure or object in, on, or under land, the surrounds of the structure or object from which it cannot be separated without destroying or diminishing its value or significance. All “Items of the Queensland Estate” are protected, regardless of whether they are entered on a register. Under the Cultural Record Act any systematic investigation of places covered by the provisions of the Act must be carried out under a permit.

Information relating to the cultural heritage of the study area may be found in unpublished consultancy reports, conducted under permit, for EIS-related assessments (eg infrastructure networks such as road, power lines, optic fibre cables), these are held by the QEPA. The archaeological site register held by this Agency is currently closed. Written correspondence was received from Ms Jana Kahabka, Cultural Heritage Unit, EPA (Far Northern Region) on (19 March 2001), advising that “if developments are planned for the Mulgrave River Catchment a Cultural Heritage Assessment Study should conducted prior to the development…” the Department’s comments are attached (Appendix 3).

Aboriginal peoples are known to have exploited the wet tropics region, possibly for as long as 40,000 years. The coastal regions and forests of the study area are of significance to existing Aboriginal communities who act as traditional custodians and who retain their traditional attachment to the land. The Russell-Mulgrave Catchment Rehabilitation Plan: Summary Rehabilitation Plan (NQ Joint Board, 1998) identifies a number of Aboriginal linguistic groups whose traditional homelands centre round the Russell-Mulgrave catchment (NQ Joint Board, 1998). Aboriginal cultural heritage sites typically occur along the major watercourses of the area and include village, camp and cave sites, story sites, stone fish traps, and meeting and corroboree grounds.

Cultural heritage assessments conducted under the provisions of the Cultural Record Act would require consultation with the traditional custodians of the land. As a first step in the consultation process, the North Queensland Land Council (Cairns) would need to be consulted for advice on appropriate indigenous contacts in the Russell-Mulgrave region.

Historical (non-Aboriginal) exploitation of the resources of the Mulgrave Valley began in the late 1800’s, when timber getters began exploiting the rainforest for commercial timbers. Today the wet tropics region is highly significant as a national and international tourist destination. As the QEPA’s Site Register is currently closed we were unable to ascertain if there are any recorded historical cultural heritage places in the vicinity of the Russell-Mulgrave area. However, this does not mean that there are no places. The historical development of the area indicates that there is a potential for unknown cultural heritage places to be located in the study area.

The Russell-Mulgrave Catchment Rehabilitation Plan: Summary Report on Rehabilitation Needs (NQ Joint Board, 1998) provides the following recommendations:

“It is important to ensure that destruction or damage to cultural places does not occur unwittingly or accidentally and that the values of each place are considered in land use planning with involvement of relevant sections of the community… Provision needs to be made for the protection and management of those sites that are considered significant…in any works programs, including those that are aimed at landscape repair and natural resource enhancement.”

Major rehabilitation works that result from recommendations made in this Action Plan will require cultural heritage surveys to be undertaken if there is a chance that such work could impact on cultural heritage sites.

Natural Resource Assessments Pty Ltd 16 24 May 2001 Mulgrave River Management Action Plan

6. Geomorphological Assessment (Stage 3)

Summary Bank erosion along the Mulgrave River is rated as moderate in extent and is largely confined to the outer bank of meander bends, particularly in those reaches with a relatively high sinuosity. This erosion is deemed to be natural and not necessarily a function of human intervention in this stream system. It would appear that the bed of the Mulgrave River in its middle and lower reaches is aggrading with medium to coarse-grained sands and point bars, in-channel benches and mid-channel bars also appear to be actively accreting. This aggradation is unlikely to be due to bank erosion in the middle to lower reaches as sediments within these banks are generally finer than medium-grained sands. The accreting sands are composed of quartz, feldspars and mica and it is likely that the sediments have been derived from granites in the upper catchment. It is possible that logging, in-channel mining, and stream diversion over the last century may have liberated substantial quantities of sediment.

Analysis of flood records from the Mulgrave River show quasi-cyclic decadal flood and drought dominated regimes since 1916 with the catchment over the majority of this time experiencing a relatively low discharge flood regime. Ungauged but observed flood levels in the very early 1900’s and late 1800’s throughout several catchments in the Wet Tropics, including the Mulgrave River catchment, suggest that floods were considerably larger at this time. Since this time it is possible that the channel of the Mulgrave River has been naturally contracting and aggrading due to a lower flood discharge regime coupled with an increasing sediment supply due to European style land practices in the upper catchment. There is little doubt that a higher discharge flood regime will return in the future, especially if climate change predictions are correct, and this will result in channel expansion, partly involving increased bank erosion. It is suggested that management of the catchment incorporates the precautionary principle and plans for such a possibility. The impacts of future changes in sediment delivery to the coast need also to be considered especially under a scenario of rising sea-levels.

Introduction This report discusses the extent and location of bank erosion along the Mulgrave River. It also briefly examines the flood history of the Mulgrave River from gauged records and the possible reasons for changes in the characteristics of the river channel over the last century. Recommendations are made concerning future management of the river in terms of bank erosion, especially in light of the possible consequences of future climate change and natural quasi-cycles of flooding within the catchment over the last century.

Natural Resource Assessments Pty Ltd 17 24 May 2001 Mulgrave River Management Action Plan

Geology and Soils of the Catchment The Mulgrave River rises in the Bellenden Ker Range and flows northward, then eastwards through the escarpment and lower slopes of the highlands, and turns south on the alluvial floodplain of the lower reaches to join with the Russell River and enter the sea at Russell Heads. The headwater tributaries of the Mulgrave River drain parts of the eastern edge of the basalt covered Atherton Tableland. The main stream then flows through the granites of the Bellenden Ker Range, and the predominantly metamorphics through the lower reaches. An extensive alluvial fan extends from the foothills into the broad north-south trending valley known as the Mulgrave corridor. In the lowermost reaches marine sand deposits, freshwater swamps, and tidal estuaries occur. Soils of the catchment vary depending upon the underlying lithology. In this region granites produce red podzolics, and red, yellow and grey earths. These soils also predominate on the metamorphics. Basalts typically produce krasnozems. These soils are the source of material for sediments being delivered to the stream network.

Hydrology Flood History The headwaters of the Mulgrave River receive close to, if not, the highest annual average rainfalls on the Australian continent. Approximately 64% of this rainfall is transmitted via the stream network to the sea and virtually all streams in the catchment are perennial except for a few that drain areas of rain shadow on the west and northwestern sides of ranges.

Figure 2: Five Year Running Mean of Maximum Monthly Instantaneous Flood Discharges on the Mulgrave River for the Years 1916 – 1999 The years 1962 – 1971 on curve are unreliable as they represent the missing years from 1959-1967 in the raw data set. Data was compiled from gauging stations at Gordonvale and Peet’s Bridge.

2000 1800 1600 1400 1200 1000 800 600 400

Discharge (cumecs) 200 0 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000

Like many other streams along Australia’s eastern seaboard, the flood history of the Mulgrave catchment over the last approximately 80 years shows decadal length quasi-cycles of flooding suggestive of flood and drought dominated regimes. Figure 2 shows these cycles.

Natural Resource Assessments Pty Ltd 18 24 May 2001 Mulgrave River Management Action Plan

As has been noted by Erskine and Warner (1988) flooding regimes in many stream catchments of eastern Australia are crudely cyclic at decadal scales. Periods when peak flood discharges are relatively low have been named drought dominated regimes as opposed to flood dominated regimes when peak flood discharges are relatively high. The curve in Figure 2 suggests that decadal flood cycles are also evident on the Mulgrave River. Periods of higher flood discharges occurred during the 1930’s, 1970’s and a possible start to such a phase during the late 1990’s. Intervening periods experienced generally lower discharges. Because discharge records generally are no longer than 80 – 100 years for many catchments, it has not been possible to determine if any such cycles occur at longer periodicities or whether the magnitude of any cycles may vary at longer periodicities. It is interesting to note however that the largest floods recorded, but not by gauging stations, on several of the major streams draining the wet tropics occurred just before gauged records commenced in the region (ie 1911, 1913 and during the late 1800’s). These floods, as determined from observed flood height levels, had discharges close to double that of any floods recorded since. Alluvial streams are the authors of their own geometrise (Leopold, Wolman and Miller, 1964) which means that they adjust their hydraulic geometry, or channel characteristics, to the prevailing discharge regime. Another way to express this is through the continuity equation where discharge = width x depth x velocity. Hence when discharge varies so to does the depth and width and possibly flow velocity of a stream. In this manner it has been proposed that streams respond to drought and flood dominated regimes. During drought dominated regimes channels often narrow and aggrade, while during flood dominated regimes channels widen and become more erosive. While not in the Mulgrave catchment, Thomatis Creek, a distributary of the Barron River, has responded in such a manner throughout the 1900’s. Whether the Mulgrave has undergone episodic channel size reduction and expansion in response to these cycles is beyond the scope of this study but such an investigation is important before any final recommendations concerning long-term management and remediation options are made for this stream. However, like other streams in the Wet Tropics and elsewhere throughout eastern Australia, it is possible that the Mulgrave River has responded to these flood cycles and since the late 1970’s has experienced some channel contraction due to the lower flood regime. This would result in channel bed aggradation and relatively less bank erosion. It must be stressed though that channel bank erosion, especially on the outer bank of meanders, is a normal process and one that will operate during lower flood regimes as a channel constantly aims to achieve equilibrium and minimal energy loss.

Extent and Location of Erosion On-site investigations of the Mulgrave River revealed that the vast majority of bank erosion is presently occurring on the outer bank of meander bends. In most instances rock revetment structures have been emplaced to reduce this erosion. Aerial photo analysis along with the field observations suggest that the extent of erosion and potential erosion along the Mulgrave River is only moderate. Meandering rivers flowing through alluvial floodplains naturally migrate and one of the outcomes of this process is a minimisation of energy loss, or work performed, along the length of a stream. At times in the history of a stream, different reaches will increase and decrease their sinuosity in concert with similar variations in other reaches. Hard engineering works constrain the natural migration of a meandering stream across its floodplain and it is likely that this will have impacts on other reaches. From a geomorphic perspective it is important to view the stream system as an integrated network. One of the potential constraints here though is the loss of agricultural land and infrastructure and therefore a compromise must be achieved. However, it is also important to note that bank erosion is entirely natural and need not be a consequence of human intervention.

Natural Resource Assessments Pty Ltd 19 24 May 2001 Mulgrave River Management Action Plan

On an immediate cost recovery basis, bank erosion resulting in loss of infrastructure is a concern. One site presently experiencing erosion is the south bank of the Mulgrave River upstream of the Bruce Highway bridge near Gordonvale. This site is not on the outer bank of a meander bend but is a straight stretch of stream. Aggradation appears to be occurring on the opposite bank immediately upstream of this site. While the channel here does not exhibit a meandering planform the flow during moderate to high discharges may meander and it is possible that the southern bank is eroding under the influence of such a flow. The present erosion may be the precursor to a change in channel planform towards a more meandering state. The causes behind this potential scenario are not clear from the brief field observations but may be elucidated by detailed hydraulic modelling of the site.

Bed Aggradation Oral history suggests that Mulgrave River has undergone substantial bed aggradation since the first European inhabitants of the region navigated the river by boat. It is argued that the river must have been generally deeper at least to a point not far downstream of Gordonvale. Observations during this brief study suggest that the stream bed is experiencing aggradation as the entire length from Gordonvale downstream is entirely covered by medium- to coarse- grained sands. Nowhere was bedrock observed on the stream bed except where the stream appears to have been dammed at low flows near the Mulgrave sugar mill. Point bars at many meander bends and in-channel benches appear to be accreting and there are channel bars developing at several locations. The sediment deposited to form these features has been derived from granites in the upper catchment as it is composed of sand-sized grains of quartz, felspar and mica. There is some opinion that accumulation of this sediment in the stream is a function of stream bank erosion. If this is the case then the floodplain or channel bank sediments should contain substantial quantities of the same sediment presently accumulating in the stream. Detailed grain size analysis of floodplain sediments and calculation of the volumes of different sediment textures in the channel banks and in the stream need to be made before a definitive conclusion on this matter can be made. Brief inspection of the channel banks at a number of sites downstream of Gordonvale shows they are largely composed of sediments finer than fine- to medium-grained sands suggesting that these deposits are not a significant contributor to the accumulation of the coarse-grained sand in the channel. It seems more likely that the source of these sediments and/or reason for the apparent channel bed aggradation lies elsewhere in the catchment. This reasoning however does not discount the possibility that bank erosion in the upper catchment may be providing some of this sediment.

There is little doubt that European style land practices and use within stream catchments throughout northeast Queensland have resulted in substantial increases in sediment delivery to streams. Several studies have been undertaken of sediment yields in catchments through this region, including the Mulgrave River resulting in the development of models of sediment yield delivery rates to the Great Barrier Reef Lagoon (Belperio, 1979; Moss et al. 1983; Neil and Yu 1995, 1996, Wasson 1994, 1996). The majority of these models, and certainly the most recent ones, have been primarily concerned with suspended sediments and not bedload, or sand or larger grain sizes. Some studies have suggested that there is a proportional relationship between sediment delivery rates of suspended and bedload sediments it is worthwhile briefly discussing these models here. (The full report containing these discussions is appended in Appendix 4).

Natural Resource Assessments Pty Ltd 20 24 May 2001 Mulgrave River Management Action Plan

Aggradation of sand on the channel bed is likely to have been caused by a number of factors. Logging in the upper Mulgrave catchment may have contributed substantial volumes of bedload material to the stream network. Mining of sand sized and coarser-grained deposits along the length of the stream may have also liberated sediment that has now been transported and deposited downstream. Diversion of the stream channel would also result in similar consequences. It is unlikely though that channel bank erosion in the middle to lower reaches is a significant factor, however this needs to be examined further. Each of these human interventions should also be viewed in light of the flooding history of the stream. If the late 1800’s and early 1900’s were a period of exceptionally large floods then it is likely that the channel of the Mulgrave River may have expanded considerably at this time. This then would have been the likely state of the river when Europeans first settled the area. Since that time, and during distinct episodes of lower flood discharges such as the 1920’s, 1940’s, mid-1950’s to early 1970’s and from the late 1970’s to 1990’s, the channel may have undergone substantial contraction and bed aggradation under a regime of increasing sediment supply as a result of the consequences of logging, mining and channel diversions. It is important to remember that a return to a higher discharge regime in the future is inevitable and substantial flushing of sediment from the channel will occur. Sediment within the channel is also a very important source of sand for coastal beach nourishment. Sediment removed from the stream system today will result in future depletion of sand for beaches in the future resulting in coastal erosion. It is also necessary to consider the impact of future climate change in this region on the stream system and coastal beaches. There is generally wide consensus that climate change in this region will result in more extreme meteorological events such as storms and floods and coupled with possible sea-level rise there will be substantial impacts to river channel and coastal beach behaviour. If flood magnitudes do increase in the near future then the extent of channel bank erosion may also increase. Planning for such a scenario is imperative and accords with employment of the precautionary principle.

Conclusions Bank erosion on the Mulgrave River, particularly in the middle and lower reaches, is moderate in terms of severity and extent. This erosion is primarily occurring on the outer banks of meander bends. At one site however, erosion of the south bank of the river immediately upstream of the Bruce Highway bridge near Gordonvale is occurring along a straight reach. A detailed hydraulic study needs to be undertaken here to ascertain why this erosion is occurring as it threatens significant infrastructure.

The bed of the Mulgrave River appears to be aggrading and point bars and in-channel bars likewise appear to be accreting. It is unlikely that bank erosion in the middle and lower reaches is responsible for this aggradation. Rather it is hypothesised that logging, in-channel and floodplain mining or sediment extraction along with channel diversion in places may have liberated substantial quantities of sediment into the stream system. It is also likely that these land use practices were superimposed upon a flood regime of generally or relatively low flood discharges since the very early 1900’s which in itself would have led to channel contraction and bed aggradation. Decadal length flood dominated and drought dominated regimes are evident from gauged discharge records on the Mulgrave River and these suggest that a return to a flood regime may occur in the near future. Along with potential increases in flood magnitudes under a future altered climate the potential for increasing rates of bank erosion in the near future is high. These possible future scenarios need to be considered in the management of the Mulgrave River catchment.

Natural Resource Assessments Pty Ltd 21 24 May 2001 Mulgrave River Management Action Plan

Further studies are required to accurately assess the roles of various forms of human intervention in changing channel characteristics in the Mulgrave catchment. These studies will require detailed sediment texture analyses of floodplain and in-channel sediments, calculation of the likely volumes of sediment liberated by various land use practices and the amounts extracted from the stream system. Historical changes in the planform and cross-sectional characteristics of the Mulgrave River channel also needs to be undertaken. This information is important for understanding the causes of both recent past and likely future changes in the behaviour of the Mulgrave River.

Natural Resource Assessments Pty Ltd 22 24 May 2001 Mulgrave River Management Action Plan

7. Field studies (Stage 4)

Prior to the field assessment the Mulgrave River was subdivided into broad sections (Figure 1). These sections were subdivided into reaches during field work based on the habitat changes and infrastructure locations. This resulted in the following dissection of the lower Mulgrave River (note: left and right banks are defined looking downstream).

Section 1 Section 1 starts from The Fisheries (including bridge crossing and approximately 100 m upstream area) to Peet’s Bridge and contains two reaches: reach 1.1 extends to the confluence with the Little Mulgrave and reach 1.2 starts at this confluence and extends to Peet’s Bridge (inclusive).

Section 2 Reach 2.1 starts from Peet’s Bridge to the Bruce Highway Bridge in Gordonvale. The second reach 2.2 starts approximately 1 km before the Bruce Highway bridge at Gordonvale.

Section 3 Reach 3.1 is located between the Bruce Highway bridge at Gordonvale and the Mulgrave Mill rock barrage. Reach 3.2 follows this rock barrage and the outer bend past the anabranch ending at Lmk 004. Reach 3.3 continues from Lmk 004 until the reduction of the LHS riparian vegetation (Lmk 009).

Section 4 Section 4 begins at Lmk 009 and extends to Kenny’s Bridge (Lmk 016). It is subdivided into reach 4.1, which includes the double S bends near Aloomba township and finishes at Lmk 014. Reach 4.2 comprises a large left bend, which connects with the Malbon Thomson Range for several hundred metres and ends at Kenny’s Bridge (Lmk 016).

Section 5 Reach 5.1 starts at Kenny’s Bridge and extends past Campbells Creek (Lmk 016). The extent of reach 5.2 is defined by the confluence with Behana Creek (Lmk 022). This is followed by reach 5.3, which finishes at a cane train bridge (Lmk 025).

Section 6 Reach 6.1 starts below the cane train bridge and extends to Laing’s Creek (Lmk 032). This is followed by reach 6.2, which extends to Barbagallo’s Bridge (Lmk 033). Reach 6.3 begins past Barbagello’s Bridge and ends at an unnamed creek (Lmk 036) below Hobson’s Creek. Reach 6.4 extends from this to the Rusty Creek confluence (Lmk 40).

Section 7 This section starts at the Rusty Creek confluence and ends at Lmk 050. Reach 7.1 extends to immediately before Tanner’s Lagoon (Lmk 045). Reach 7.2 includes Tanner’s Lagoon and ends immediately before the Figtree Creek confluence (Lmk 48). This is followed by reach 7.3, which ends before the large right bend (Lmk 050) before Deeral Landing.

Natural Resource Assessments Pty Ltd 23 24 May 2001 Mulgrave River Management Action Plan

Section 8 Reach 8.1 includes the Deeral Landing bend and extends to the last houses on the right hand side of Deeral Landing (Lmk 53). Reach 8.2 continues to the confluence with the Russell River. The Mutchero Inlet was defined as reach 8.3.

Section: Little Mulgrave Extends from the Gillies Highway bridge crossing of the Little Mulgrave (including the picnic area) downstream to its confluence with the Mulgrave River.

Section: Fishery Creek Fishery Creek below the Bruce Highway and downstream toward the Mulgrave River before it opens into a cane drain.

Section: Figtree Creek Figtree Creek below the Bruce Highway to its confluence with the Mulgrave River.

Figure 1 provides a graphic view of the location of each section. The accompanying CD contains photographs taken during the field investigation. Appendix 6 provides a list of plates.

Natural Resource Assessments Pty Ltd 24 24 May 2001 Mulgrave River Management Action Plan

8. Mulgrave River Draft Management Action Plan (Stage 4)

The subsequent development of the Draft Management Action Plan occurred in three steps. 1. Categorisation of sections and associated issues. 2. Field assessment. 3. Prioritisation of rehabilitation works.

Sections and reaches were described using the field data collected (Appendix 5). Erosion potential was determined by the geomorphological assessment and verified by field observations. Ratings (1 – Low; 2 – Medium; 3 – High; and 4 – Very High) were applied to the following environmental, social, and engineering issues within each reach. · Erodibility of the reach. · Sediment aggradation in reach. · Riparian habitat value. · Conservation value (such as connectivity). · Instream habitat (including water quality). · Downstream impacts (eg weed source). · Flood control required (eg infrastructure protection). · Recreation potential. · Weed control required. · Revegetation required.

Table 2 provides a summary of issues and ratings. It also provides costings for the proposed rehabilitation measures. All area calculations were made from 1997 aerial photographs (approximate scale 1:25000) and consequently are approximates only as are the costs derived from these areas. Cost estimates for revegetation and weed control were based on costs of $25000 per ha including five year maintenance period. Costings do not include long-term monitoring and data collation/analyses. Due to an absence of in situ investigation the estimated costs have restricted reliability, however, they provide the best available guide. With respect to site-specific engineering related works it will be essential to undertake further work (eg in situ sampling, further analysis) prior to preparation of specifications suitable for release to tender.

8.1 Reach Prioritisation

The development of a River Management Action Plan requires the consideration of multiple natural processes and multiple objectives. The objectives of reach prioritisation are to ensure actions have multiple positive outcomes. The four expected outcomes of the MRMAP are to: · maintain and enhance areas that have retained higher ecological values (Rutherford et al 1999)

Natural Resource Assessments Pty Ltd 25 24 May 2001 Mulgrave River Management Action Plan

· afford high priority to actions within reaches that address multiple issues (eg ecological and physical and social) · place high priority on actions that have off-site benefits for physical river processes both upstream and downstream · afford priorities to upstream sites when priority between reaches is uncertain ie where the same score is recorded for separate sites, priority is given to upstream sites.

To achieve this, sorting rules were applied to the reach matrix (Table 3). Rule 1: Count the number of issues in Table 2 with High (3) or Very High (4) ratings. Use as highest priority. Rule 2: Count the number of issues in Table 2 with Very High (4) rating. Use as second highest priority. Rule 3: Count the number of issues in Table 2 with High (3) rating. Use as third highest priority. Rule 4: Place reaches of upstream sections first. Use as fourth highest priority.

8.2 Results

This study found that rehabilitation of the Mulgrave River can generally best be achieved through weed control and revegetation of the riparian zone (costings given for such measures only include within bank rehabilitation measures). Some specific ‘hard’ measures are identified for specific sites (Table 2). To achieve re-establishment of an ecologically sustainable river that can function as a integral part of the landscape, natural long-term migration must be taken into account - as must a riparian zone that extends beyond the high bank. Including a wider riparian strip, particularly at erosive bends, allows for the river to naturally erode. The rate of loss will be reduced in areas with established riparian vegetation that is wider than the high bank (Rutherford et al 1999).

A prioritisation of reaches to be rehabilitated has been established (Table 3), the first three (3) upstream reaches on the Mulgrave are the highest priority. Rehabilitation of reaches 1.1 to 2.1 would provide best value for money. Importantly it should be noted that treatment of these upstream areas will provide benefits for downstream reaches in the form of reduced sedimentation and improved water quality.

Although the reaches to be rehabilitated have been prioritised by the ranking system employed, it is not suggested that reaches with lower ratings are not deserving of rehabilitation effort. These reaches (eg 3.2, 4.1, 5.1, 5.2 and 6.3) had high ratings for at least one issue, mostly that of habitat quality or sediment aggradation.

Rehabilitation works undertaken should follow best practice management, incorporating monitoring and documentation to assess the success or failure of works undertaken. This approach, if incorporated into adaptive management of the river works, will assist in the achievement of successful long-term rehabilitation. This is particularly important given the expected increase in flooding due to climate changes (Section 6, Geomorphology). In this scenario an increased riparian width (extending beyond the high bank) will be important to accommodate erosion processes.

Natural Resource Assessments Pty Ltd 26 24 May 2001 Mulgrave River Management Action Plan

Table 2: Summary Table of Issue Ratings as Determined by Field Assessment aggradation

Estimated 1 Reach Restoration Measures Area Comments

Erodability Sediment Riparian habitat Conservation Instream habitat downstream impacts Flood control required Recreation potential Weed control required Revegetation suggested Costs

2 1.1 2 3 4 4 3 3 1 3 3 3 Revegetation / Weed Control 11 ha $275,000 1.2 1 2 3 3 3 3 1 4 3 3 Revegetation/ Weed Control 5.5 ha $137,500 2.1 1 2 4 4 4 3 1 3 3 3 Revegetation/ Weed Control 19.9 ha $497,500 n/a No estimates can be made until n/a hydraulic modelling is 2.2 3 3 2 2 1 4 1 4 2 2 Revegetation/ Weed Control ascertained. Infrastructure value is extremely high: 2 bridges and main water pipeline. Revegetation/ Weed Control 6.5 ha $168,500 3.1 2 2 1 1 1 1 2 1 3 3 and Reshaping of Rock Barrage Revegetation/ Weed Control, 2 ha $92,000 3.2 1 3 1 1 1 2 1 1 2 2 Rock Revetment Securing Mill Manager’s House 9.4 ha includes pointbars, instream $235,000 3.3 1 2 1 1 2 3 1 1 3 3 Revegetation/ Weed Control elongated bar 4.1 3 2 1 1 2 2 1 1 2 2 Revegetation/ Weed Control 24 ha $600,000 4.2 1 1 3 3 3 2 1 1 2 2 Revegetation/ Weed Control 3 ha $75,000 10 ha Rock revetment upstream of $300,000 5.1 2 2 1 1 3 2 1 1 2 2 Revegetation/ Weed Control Bennetts Bridge 5.2 2 2 1 1 3 2 1 1 2 2 Revegetation/ Weed Control 2 ha $50,000 5.3 2 2 2 1 3 2 1 1 2 2 Revegetation/ Weed Control 5.7 ha $142,500 6.1 1 1 3 2 3 1 1 1 1 1 Revegetation/Weed Control 1 ha $25,000

Natural Resource Assessments Pty Ltd 27 24 May 2001 Mulgrave River Management Action Plan aggradation

Estimated 1 Reach Restoration Measures Area Comments

Erodability Sediment Riparian habitat Conservation Instream habitat downstream impacts Flood control required Recreation potential Weed control required Revegetation suggested Costs 6.2 3 1 4 4 2 1 1 1 1 1 Revegetation/Weed Control 1.5 ha $37,500 6.3 2 1 1 1 3 1 1 1 2 2 Revegetation/Weed Control 2.5 ha both sides $62,500 30 m width $200,000 6.4 1 2 3 2 3 1 1 1 2 2 Revegetation/Weed Control 8 ha. 7.1 1 2 2 2 2 2 1 1 2 2 Revegetation/Weed Control 4 ha LHS & RHS where cleared $100,000 1.7 km x 20 m = 3 $75,000 7.2 1 1 3 3 3 1 1 1 1 1 Revegetation/Weed Control ha 2 km x 20 m = $100,000 7.3 1 1 3 3 3 1 1 1 2 2 Revegetation/Weed Control 4 ha 8.1 1 1 3 2 3 1 1 3 2 2 Revegetation/Weed Control 2ha $50,000 1.5ha Nomination of boat ramp 2.5km $37,500 8.2 1 1 4 4 3 1 1 4 1 1 Revegetation/Weed Control below Deeral 8.3 1 1 4 4 4 1 1 4 1 1 None $0 Figtree Ck 2 2 3 3 3 1 1 1 2 2 Revegetation/Weed Control 2.5 ha in patches $62,500 Revegetation/Weed Control + 2.5 ha $73,000 Fishery Ck 2 2 1 1 3 1 1 1 2 2 Rock Revetment in outer bend stream bank to protect native bush Little Mulgrave 1 1 2 2 3 1 1 3 2 2 Revegetation/Weed Control 2.4 ha $60,000 1 Descriptions presented in Appendix 5 and photographs provided on CD. 2 Refer to Section 9.2 Work Specific Recommendations

28 Natural Resource Assessments Pty Ltd 24 May 2001 Mulgrave River Management Action Plan

Table 3: Matrix of Reaches Ordered According to Four Prioritisation Rules

Reach Costs in $1 Rule 1 Rule 2 Rule 3 Rule 4 1.1 275000 8 2 6 1 2.1 497500 7 3 4 2 1.2 137500 7 1 6 1 8.3 0+ 4 4 0 8 8.2 37500* 4 3 1 8 2.2 N/a# 4 2 2 2 6.2 37500 3 2 1 6 Figtree Ck 62500 3 0 3 1 3.3 235000 3 0 3 3 4.2 75000 3 0 3 4 7.2 75000 3 0 3 7 7.3 100000 3 0 3 7 8.1 50000 3 0 3 8 Little Mulgrave 60000 2 0 2 1 3.1 168500 2 0 2 3 6.1 25000 2 0 2 6 6.4 200000 2 0 2 6 Fishery Ck 73000 1 0 1 1 3.2 92000 1 0 1 3 4.1 600000 1 0 1 4 5.1 300000 1 0 1 5 5.2 50000 1 0 1 5 5.3 142500 1 0 1 5 6.3 62500 1 0 1 6 7.1 100000 0 0 0 7 + Although no costs are associated with this reach, its protection and the restriction of human activities, particularly at the extension of Russell Heads, is important. * This does not include costing for construction of a new boatramp including infrastructure and land purchase (estimated to a total of $1,260,000). # No cost estimates could be provided until hydraulic modelling is undertaken. The infrastructure value at this reach is considered to be very high. Further investigation works appear to be essential and to have a high priority. 1 Estimated costs – the reliability of which can be improved through site-specific evaluations.

Natural Resource Assessments Pty Ltd 29 24 May 2001 Mulgrave River Management Action Plan

9. Implementation

This assessment has incorporated a holistic approach that relies on the expertise of a multi- disciplinary team of experts, and incorporates the issues perceived as important by the community and the landholders. It replaces resource intensive quantitative research assessments with expert knowledge (whether that be technical or experiential). In a quantitative approach the prioritisation and inclusion of issues perceived as important also requires a subjective weighting of issues when deriving a prioritisation matrix. In this study the subjective qualifier was supplied by the experts and the community consultation phase and the prioritisation of reaches followed simple repeatable rules.

9.1 Strategies

To implement the MRMAP (Mulgrave River Management Action Plan) successfully, close partnership and cooperation between government agencies, communities and individuals is needed. The CRIT, in conjunction with the MRWG that initiated the Mulgrave River Management Action Plan, provides a platform to encourage further cooperation between community-based organisations and government bodies. The large proportion of privately owned land along the Mulgrave River means that the cooperation and support of private land owners is vital to the successful completion of actions needed to stabilise and enhance the Mulgrave River. Community groups are the obvious choice to engage landowner support for the Mulgrave River Management Action Plan but will require the assistance of government agencies. The support of CANEGROWERS should also be sought. Implementation is directly related to the willingness of individuals, in positions of authority, to take on the responsibility. Community groups can provide independent support to these individuals and assist in cutting through jurisdictional boundaries. These groups can provide the focus necessary to achieve a coordinated response and assist natural resource managers in the task of achieving outcomes acceptable to the community. Industry organisations such as CANEGROWERS can provide assistance in encouraging grower support through raising awareness and acceptance of the benefits of restoration initiatives.

Organisations that can provide assistance are:

· Mulgrave Landcare and Catchment Group Inc. (MLCG) Coordinate a wide range of public education activities and liase with CANEGROWERS, develop projects and prepare/support funding submissions which are able to be completed in conjunction with private land holders by coordinating other organisations and agencies to assist with project completion. Use existing resources eg RIT/Rainforest Cooperative Reach Centre. · Department of Natural Resources and Mining Ensure that weed control works are conducted in State Forests. DNR Forestry should encourage and assist with the replanting of native timber species above the banks. This could provide an economic incentive for landholders to give up potentially productive land.

30 Natural Resource Assessments Pty Ltd 24 May 2001 Mulgrave River Management Action Plan

· Cairns City Council (1999) CCC has prepared a Pest Management Plan in which parts of the Mulgrave River are identified as being infested with Blue Trumpet Vine (Thunbergia grandiflora and T. laurifolia), Cucumber Tree (Palmentaria edulis), Sicklepod (Senna obtusifolia), Leucaeana (Leucaena leucocephala), Para grass (Brachiaria mutica), Pond Apple (Annona glabira), Elephant Grass (Pennesetum purpureum), and others. Particularly the upstream sections of the Mulgrave are problem zones for Thunbergia and Leucaeana. Weed control is a key aspect of the rehabilitation works described (Table 2), synergies can be achieved through co-ordination with the implementation of Cairns City Council’s Pest Management Plan. · CRIT/ MLCG/ Cairns City Council/ QEPA/ DNRM/ CANEGROWERS Landholders should be consulted and informed of the need for a larger riparian buffer especially in erosion prone sections. MLCG and CANEGROWERS could facilitate and promote a coordinated agency response. · Queensland Parks and Wildlife, universities, and bodies such as the Rainforest Cooperative Research Centre To ensure that succession of native vegetation and animal species is occurring and to determine the appropriateness of the planted species, universities and the Rainforest CRC should be encouraged to establish long-term monitoring plots in revegetated areas. Instream habitat and bank stability could also be monitored, and innovative stream rehabilitation techniques to enhance instream and riparian function (eg large woody debris, alignment training groynes) could be researched and developed. MLCG and CRIT could support such initiatives. The results of such initiatives would assist development of more appropriate methods of bank stabilisation in the highly flood prone rivers of North Queensland. · Aboriginal Communities Appropriate Aboriginal groups should be identified for the study area and mechanisms for consultation developed. Identification and protection of cultural values along the Mulgrave River increases the value of restoration works to the local community. When ‘hard’ (engineering) solutions are suggested it is recommended that a cultural heritage assessment be undertaken as part of the investigations necessary to prepare appropriate specifications for the work. · Department of Main Roads (DMR) Sites (near bridges) that DMR controls would generally benefit from upstream bank stabilisation. Encouraging and providing money for appropriate tree planting and engineering works at these sites would allow community involvement for increased ecological benefits and decreased site maintenance costs. · Local Council Where river crossings are under council control ensure that designs are in line with best practice. Where crossings are threatened by erosion ensure that riparian planting and other erosion control works are included in the stabilisation plan.

Natural Resource Assessments Pty Ltd 31 24 May 2001 Mulgrave River Management Action Plan

9.2 Work Specific Recommendations

Remediation Recommendations Specific remediation recommendations are provided in Appendix 5. Where engineering works are required schematic drawings of these works are provided. When conducting rehabilitation works along the river some general principles need to be considered:

· planting should be conducted at the end of the wet season to maximise the benefit of the end of the wet season rains and the fact that flood events have reduced weed infestations. Therefore initial weed control is more cost-effective.

· other treatment works (such as engineering works) should be conducted at the beginning of the dry season and only undertaken subsequent to the detailed, site-specific investigations necessary to prepare appropriate specifications.

· plant species selection should consider not only pre-existing vegetation communities, but also specimens that are most appropriate for current physical conditions (eg changed hydrology regime or existing substrate, which may differ considerably from similar undisturbed sites).

· erosion control measures need to be in place to minimise impact of rainfall events whilst the site is disturbed.

· generally greater follow up maintenance is required for riparian rehabilitation (eg weed control)

· revegetation in weed infested erosion zones should incorporate spot eradication of weeds followed by planting of native species. This is to maintain the stabilising effects of weed cover until such time as rehabilitation species have established.

· use non-residual herbicides to avoid herbicide contamination of waterways as leaching into the stream may occur, evaluate the requirement for permits to undertake weed control.

Further practical instruction in relation to site rehabilitation can be found in Rutherford et al (1999) and on the LWRRDC website (http://www.rivers.aus.net).

Many areas along the Mulgrave River require the enhancement and widening of the riparian buffer beyond the high bank to further protect the riverbanks. Deep rooted tree species have an enormous stabilising effect on river banks (Rutherford et al 1999) and shading from the canopy of these trees also assists in eliminating exotic grass species including Para Grass, Cow Cane and Elephant Grass infestations, which reduce the flow capacity of the river. The cost to replant areas could be lowered considerably by planting only a limited number of appropriate species. Once established these species could provide the necessary cover and habitat to facilitate succession of other native species. Rehabilitation should extend out from existing remnants and be of feasible size (considering both establishment and maintenance costs) and include plantings beyond the high bank.

32 Natural Resource Assessments Pty Ltd 24 May 2001 Mulgrave River Management Action Plan

Weed infestation along the stream bank and particularly in point bars and instream longitudinal sand bars is common to all sections of the Mulgrave River. Weeds often grow to the low water mark and may prevent a natural displacement of the sediments during floods contributing to accumulation of sediment (it should be noted that the Mulgrave River appears to be in a phase of aggradation (Section 6, Geomorphology) and point bars are a natural consequence of this phase). Weed management and revegetation of these areas with natives at the bank side of the point bars appears essential. The existing Pest Management Plan (Cairns City Council, 1999) provides a mechanism for weed management. Enhancing the implementation of this plan is recommended, and putting extra effort into securing additional resources may be necessary (estimated value of $120,000 to account for 2 personnel and equipment).

Further steps will be required before rehabilitation works are implemented. The next step requires the preparation of more detailed site specifications, especially with regard to the engineering work.

Research Recommendations · Further studies are required to accurately assess the roles of various forms of human intervention in changing channel characteristics in the Mulgrave catchment, as well as some evaluation of the effects of global warming. These studies will require detailed sediment texture analyses of floodplain and in-channel sediments, and calculation of the likely volumes of sediment liberated by various land use practices and extracted from the stream system. Recording historical changes in the planform and cross-sectional characteristics of the Mulgrave River channel also needs to be undertaken. This information is important for understanding the causes of recent past, and likely future, changes in the behaviour of the Mulgrave River (especially in the context of global warming). · Specific hydraulic studies have been recommended for Reach 2.2. · The cost/benefit of selective sand removal from specific point bars requires research. This report recommends the removal of weeds from point bars and revegetation (in part) using native vegetation. The intention is to allow stream flows to transport the non-vegetated section of the point bars (Appendix 5). The selective removal of sediment, in the context of a modified system which appears to experience increased sedimentation associated with land use change, is not unreasonable. It is essential that the selective removal be specifically and carefully planned, undertaken and monitored. It is recommended that this concept be developed and trialled. Should it prove beneficial then the development of a Code of Practice for this management technique may be developed to achieve: - uniformity/control of outcomes - necessary regulatory approval. · Monitoring the effectiveness of remediation measures and investigation trials is essential and a photographic/video record should be kept. The remediation measures presented in Appendix 5 are not a ‘quick fix’, they are a measured response to the natural system as modified by human activity. It is anticipated that river management practices will continue over time and results will be gradual, for example, sustained weed management outcomes will occur over 7 – 10 years rather than 1 – 3 years. It is important that the efficacy of the remediation measures is determined through the monitoring and that appropriate modifications to the measures are made where necessary.

Natural Resource Assessments Pty Ltd 33 24 May 2001 Mulgrave River Management Action Plan

10. Bibliography

Belperio, A.P. 1979. An inner shelf sedimentation model for the Townsville region, Great Barrier Reef Province, Unpublished PhD, James Cook University, Townsville, pp. 210.

Burrows, D. undated. FNQ 2010 Regional Environment Strategy: Key Waterways Report. Prepared for the Department of Environment (Northern Regional Office, Cairns). ACTFR, Townsville.

Cairns City Council 1999. Pest Management Plan. Cairns, Queensland 1999.

Cassells, D. S. undated. A Catchment Management Plan for the Upper Mulgrave River

Connell Wagner. 1992. Russell-Mulgrave River overview study report, stages 1-3. Connell Wagner in association with Environmental Science and Services.

DEH & DPI 1999. Testing the waters. A report on the quality of Queensland waters. Queensland Government.

DoE (Queensland) 1996. FNQ 2010 Regional Environment Strategy (draft), A report prepared by DoE under the FNQ 2010 Regional Planning Process, Cairns.

Douglas, I. 1966. Denudation rates and water chemistry of selected catchments in eastern Australia and their significance for tropical geomorphology. Unpublished PhD thesis, Australian National University, Canberra.

Douglas, I. 1967. Man, vegetation and the sediment yield from rivers. Nature 215, 925-928.

EPA 1999. State of the Environment Queensland. EPA Queensland, Brisbane 1999.

EPA, 1999. State of the Environment. Queensland 1999 prepared by Queensland Environmental Protection Agency.

Erskine, W.D., and Warner, R.F., 1988. Geomorphic effects of alternating flood and drought- dominated regimes on NSW coastal rivers. In Warner, R.F. (ed.) Fluvial Geomorphology of Australia. Academic Press, Sydney, 373p.

FNQ RPAC 2000. FNQ Regional Plan.

Gilmore, D.A. 1977. Effect of rainforest logging and clearing on water yield and quality in a high rainfall zone of northeast Queensland. Hydrology Symposium, Brisbane. Institute of Engineers, Australia, pp. 156-160.

Hausler, G. 1991. ‘Hydrology of North Queensland Coastal Streams and their Groundwaters’, in Land Use Patterns and Nutrient Loading of the Great Barrier Reef Lagoon: Proceedings of a Workshop held at James Cook University of North Queensland, 17- 18 November 1999. ed D. Yellowlees. JCU, Townsville.

Holz, G. K. 1985. Land Resources and Land Suitability Mulgrave Shire (Northern Part). Queensland Department of Primary Industries, Brisbane.

34 Natural Resource Assessments Pty Ltd 24 May 2001 Mulgrave River Management Action Plan

Hunter, H. 1997. Land use impacts on water quality in the Johnstone River catchment. Department of Natural Resources, Qld.

I.D.A. Pty Ltd. 1995. Mulgrave Shire River Improvement Trust: Strategic Management Plan for Reach 4 of the Russell River, p. 122.

ID & A Pty Ltd 2000. Benchmarking Activities of Agencies involved in Waterways Management. Final report for Melbourne Water Corporation Waterways Unit, Department of Natural Resources and Environment North East Catchment Management Authority, 2000.

Kapitzke, I. R. 1999a, 'Stream rehabilitation essentials: A conceptual framework and an integrated planning and design procedure', Proceedings of the 2nd Australian Stream Management Conference, Adelaide, pp. 365-370.

Kapitzke, I. R. 1999b, 'The practitioner's path to successful stream rehabilitation: From principles, policies and management planning to project planning, design and implementation', Proceedings of the 2nd Brisbane River Symposium, Brisbane.

Kapitzke, I. R., Pearson, R. G., Smithers, S. G., Crees, M. R., Sands, L. B., Skull, S. D. & Johnston, A. J. 1998. Stream Stabilisation for Rehabilitation in North-east Queensland. LWRRDC, Canberra.

Moss, A.J., Rayment, G.E., Remy, N. and Best, E.K. 1993. A preliminary assessment of sediment and nutrient exports from Queensland coastal catchments. Department of Primary Industries, Environmental Technical Report, No. 5.

Neil, D.T. and B. Yu. 1995. Simple climate driven models for estimating sediment input to the Great Barrier reef Lagoon, In Larcombe, P. and Woolfe, K.J. (eds.) Great Barrier Reef: Terrigenous Flux and Human Impacts. CRC Reef Research Centre, Research Symposium Proceedings, Townsville, pp. 67-73.

Neil, D.T. and B. Yu. 1996. Fluvial sediment yield to the Great Barrier Reef Lagoon: Spatial patterns and the effect of land use. In Hunter, I.M., Eyles, A.G. and Rayment, G.E. (eds.) Proceedings of conference on downstream effects of land use, Rockhampton, April 1995, Dept. Natural Resources, Queensland.

NQ Joint Board, 1998. Russell-Mulgrave Catchment Rehabilitation Plan: Summary Report on Rehabilitation Needs. Prepared for NQ Joint Board, Cairns.

NRA & SMEC, 2001. Discussion Paper No. 1: Influences on Waterways Management in Cairns. Prepared for Cairns City Council.

NRA, River Research Pty Ltd, & Australian Centre for Tropical Freshwater Research, 1999. Conservation Values of Waterways in the Wet Tropics World Heritage Area. Prepared for Wet Tropics Management Authority.

Pringle, A.W. 1986. Causes and effects of changes in fluvial sediment yield to the northeast Queensland coast, Australia., Department of Geography, James Cook University, Townsville, Monograph Series, Occasional Paper 4, p. 128.

Prosser, I. 1996. Using riparian zones to control sediment, nutrients and erosion in the Johnstone River, far north Queensland. Johnstone River Workshop, Johnstone River Catchment Coordinating Committee, Innisfail, p. 6.

Natural Resource Assessments Pty Ltd 35 24 May 2001 Mulgrave River Management Action Plan

Prove, B.G. 1991. A study of the hydrological and erosional processes under sugar cane culture on the wet tropical coast of northeastern Australia. Unpublished PhD thesis, James Cook University, Townsville, p. 272.

RMCCC, 1997. Strategic Plan of The Russell and Mulgrave Rivers Catchment Co-ordinating Committee. Prepared for the Russell and Mulgrave Rivers Catchment Co-ordinating Committee.

Russell, D. J., Hales, P. W. & Helmke, S. A., 1996. Stream Habitat and Fish Resources in the Russell and Mulgrave Rivers Catchment. Department of Primary Industries, Northern Fisheries Centre, Cairns.

Rutherfurd, I., Jerie, K. & Marsh, N. 1999. A Rehabilitation Manual for Australian Streams, CRC for Catchment Hydrology & LWRRDC, Canberra.

Sattler, P. S. & Williams, R. D. 1999. The Conservation Status of Queensland’s Bioregional Ecosystems. Environmental Protection Agency, Brisbane.

Truswell, E.M. 1990. “Australian rainforests: the 100 million year record.” Chapter 1 in Australian Tropical Rainforests. Science – Values – Meaning. Edited by L.J. Webb and J. Kikkawa. CSIRO Publications, Melbourne.

Wasson, R.J. 1994. Annual and decadal variation of sediment yield in Australia and some global comparisons. In, Olive, L.J., Loughran, R.J. and Kesby, J.A. (eds.). Variability in stream erosion and sediment transport, IAHS Publication no. 224, pp. 269-279.

Wasson, R.J. 1996. Run off from the land to the rivers and the sea. CRC Reef Research Centre, Research Symposium Proceedings, Townsville, p 1-24.

Webb, L.J. and Tracey, J.G. 1981. “Australian rainforests: patterns and change, in Ecological Biogeography of Australia. Edited by A. Keast. W. Junk, The Hague.

36 Natural Resource Assessments Pty Ltd 24 May 2001 Remove this hardcopy page it is for TOC use only. Appendix 1: Theoretical Context for the Study Approach Appendix 2: Example Proforma Reach Assessment Sheets Appendix 3: Letter from EPA (Cultural Heritage) Appendix 4: Geomorphological Study of the Mulgrave River - Dr J. Nott Appendix 5: Reach Descriptions and Site-specific Sketches Appendix 6: Table of Plates

Attachment 1: CD containing: Site-specific Photographs and EPBC Database Search Results