Gully Toolbox
A technical guide for the Reef Trust Gully
Erosion Control Programme 2015-16
Scott Wilkinson1, Aaron Hawdon1, Peter Hairsine2, Jenet
Austin1
1
2
CSIRO Land and Water
The Fenner School, Australian National University
1
© Commonwealth of Australia 2015
The Gully Toolbox is licensed by the Commonwealth of Australia for use under a Creative Commons Attribution
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the logo of the agency responsible for publishing the report, content supplied by third parties, and any images
depicting people. For licence conditions see: https://creativecommons.org/licenses/by/4.0/.
Attribute this document as: Wilkinson S, Hawdon A, Hairsine P, Austin J. 2015. Gully Toolbox. A technical guide
for the Reef Trust Gully Erosion Control Programme 2015-16. Commonwealth of Australia.
The Commonwealth of Australia has made all reasonable efforts to identify content supplied by third parties using
the following format ‘© Copyright, [name of third party]’.
Cover image: Gully erosion in the Upper Burdekin catchment, photographer Rebecca Bartley.
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Executive Summary
This is a guide to selecting, designing and implementing gully erosion control activities to costeffectively reduce sediment yield to the Great Barrier Reef (GBR) lagoon. It supports the Reef Trust
Gully Erosion Control Programme 2015-16.
Gully erosion supplies ~40% of the fine sediment exported into the GBR lagoon, from just 0.1% of
grazing land area. Gully erosion is where runoff cuts into the land surface to a depth of >0.3m,
usually within a sharply defined area. It occurs along drainage lines and in deep depositional soils
adjacent to some large river channels. Most gullies in the catchments of the GBR formed in the
period 1850–1900 when the focus was opening up new areas to grazing and agriculture. Gully
erosion is a problem which current land managers have in large part inherited.
As the primary goal of the Reef Trust Gully Erosion Control Programme is to improve the quality of
the water in the GBR lagoon and the contributing catchment areas are vast, the Programme is
restricted to ten priority management units. Gully erosion across these 10 units contributes more
than half of the fine sediment export contributed from gully erosion across all GBR catchments. Gully
erosion makes large per-hectare contributions to the fine sediment yield from these units because
they contain many gullies and their river systems deliver sediment efficiently to the coast without
large losses in downstream reservoirs or floodplains.
This document provides a specification of the gully erosion control activities that can be undertaken.
Cost-effectiveness is an important consideration given the extent of gully erosion to be treated in
priority areas. The first step of gully erosion control is to fence around gullies to enable vegetation to
grow with no or occasional grazing. Revegetation activities are the second step, including seeding
and planting within and around gullies and porous check-dams to assist revegetation within gullies.
Managing forage utilisation and vegetation in the catchment area that drains to the gully is
important, and is also supported by companion programs. These low-cost actions have been
demonstrated to work in reef catchments. Further control measures, including gully reshaping, road
drainage and contour ripping should only be undertaken within the programme where there are
special circumstances. Engineering approaches also have a higher risk of failure resulting in further
gullying in large runoff events.
This document also describes the monitoring that is required to support continuous learning and
improvement in gully erosion control by agencies and landholders.
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Contents
1
Introduction .................................................................................................................................... 6
1.1
The gully erosion process........................................................................................................ 6
1.2
Objectives of gully erosion control ......................................................................................... 7
1.3
Programme strategy ............................................................................................................... 7
2
Spatial patterns in gully extent ....................................................................................................... 9
3
Gully erosion control activities ..................................................................................................... 11
3.1
Fencing .................................................................................................................................. 11
3.1.1
Objective ....................................................................................................................... 11
3.1.2
Integration with other fencing requirements ............................................................... 12
3.1.3
Specifications ................................................................................................................ 12
3.2
Porous checkdams ................................................................................................................ 13
3.2.1
Functional Objective ..................................................................................................... 13
3.2.2
Construction .................................................................................................................. 13
3.2.3
Placement ..................................................................................................................... 15
3.2.4
Design example ............................................................................................................. 15
3.3
Revegetation in and around gullies ...................................................................................... 15
3.3.1
Objective ....................................................................................................................... 15
3.3.2
Specifications ................................................................................................................ 16
3.4
Forage management of paddocks draining to gullies ........................................................... 16
3.5
Water points ......................................................................................................................... 17
3.6
Contour banks and diversion banks ...................................................................................... 17
3.7
Managing road and track drainage ....................................................................................... 18
3.8
Grade control and gully head drop structures...................................................................... 18
3.8.1
Objectives...................................................................................................................... 18
3.8.2
Specifications ................................................................................................................ 18
3.9
Gully reshaping ..................................................................................................................... 19
Example ......................................................................................................................................... 20
4
Monitoring and Reporting ............................................................................................................ 20
4.1
Objectives.............................................................................................................................. 20
4.2
Summary of reporting ........................................................................................................... 21
4.3
Site reports on planned activities and before-treatment monitoring .................................. 22
4.4
Site monitoring...................................................................................................................... 25
4.4.1
Principles ....................................................................................................................... 25
4
4.4.2
Timing of monitoring .................................................................................................... 25
4.4.3
Monitoring design ......................................................................................................... 26
4.4.4
Photography to support monitoring ............................................................................. 28
4.4.5
Mapping out erosion control activities and monitoring at the site .............................. 29
4.4.6
Reporting site monitoring results ................................................................................. 32
5
Acknowledgements....................................................................................................................... 32
6
References .................................................................................................................................... 32
7
Appendix A – Maps of Gully Density in priority management units ............................................. 34
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1 Introduction
1.1 The gully erosion process
Gully erosion involves the incision of a defined drainage channel into the land surface to a depth of
more than 0.3 m. Gullies are widespread in semi-arid climates globally, caused by a combination of
climatic oscillation, geomorphic and hydraulic controls and land use (Ciesiolka, 1987).
Initiation of gully erosion is often triggered by vegetation degradation such as that caused by grazing
and drought-flood cycles. An individual gully starts when a small near-vertical wall is created at a
stock track or other disturbance, where surface runoff is concentrated in a drainage line or where
seepage reduces the strength and erosion resistance of soil during and after a major rainfall event.
The new gully expands upslope and grows in size due to the instability of the wall.
At landscape scale, gully erosion is focused in areas of deeper and less-stable soil, terrain of low to
moderate slopes or the vertical relief around river channels, and where runoff is concentrated in
drainage lines and valley bottoms.
While some gully features were noted by early European explorers, the vast majority of gullies in
Great Barrier Reef (GBR) catchments today developed following the introduction of cattle and sheep
grazing post-1850 (Shellberg et al., 2010; Wilkinson et al., 2013). Most gullies in the catchments of
the GBR would have formed in an era when the focus was on opening up new agricultural land. Gully
erosion is thus a problem which current land managers have in large part inherited. The locations of
gully erosion are also in large part determined by climatic, terrain and soil characteristics.
Today, the length of gullies in GBR catchments totals >87,000 km. Assuming a mean width of 5 m,
gully erosion covers just 0.1% of grazing land. However, analysis of sediment source tracing, erosion
mapping and load monitoring indicates that gully erosion supplies ~40% of the fine sediment (silt
and clay, <63 µm particle size) exported from river basins to the GBR lagoon (Wilkinson et al., 2015).
Figure 1. (Left) Hillslope and (right) alluvial gullies in the Burdekin River basin. Photographs by Scott Wilkinson.
Two forms of gully erosion occur within reef catchments. Hillslope gully erosion is a linear or
branching feature along a former overland flow path or drainage line. Alluvial gully erosion involves
incision of floodplains and river frontage country in deeper alluvial or depositional soils adjacent to
large streams, and is characterised by irregular gullies deviating away from the predominant
alignment of the pre-existing stream bank. Examples are shown in Figure 1. As well as creating ‘new’
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incisions in the natural land surface, gully erosion can also involve enlargement of small natural
water courses to a total size exceeding several times their prior depth and width. The resulting large
channels are generally linear in form but may develop many branches.
1.2 Objectives of gully erosion control
Experience has shown that once a gully has formed, stopping gully erosion completely is impractical
or very expensive. Gully erosion control aims to reduce the sediment yield from gullies into streams
and rivers, by increasing sediment trapping within the gully channel to stabilise its form, and by
slowing erosion of sidewalls and of the gully head (Figure 2).
Figure 2. The principles of gully erosion control for reducing gully sediment yield (Wilkinson et al., 2015).
The principles of gully erosion control are long-established (Geyik, 1986). The first principles is to
increase the resistance to soil erosion and sediment transport by increasing the vegetation in and
around gullies, which are often denuded or contain very little vegetation. Reducing runoff and
seepage into gullies can also be effective. However, gullies with exposed soil require little runoff to
continue eroding. Runoff can be physically diverted away from the gully head but it can be difficult
to discharge diverted runoff safely without creating new gullies. Improving soil health is a second
way to reduce runoff into the gully, but it can require large changes in grazing pressure and take a
long time to achieve substantial impacts on runoff where vegetation has become degraded. Gullies
will remain locations of higher vulnerability to erosion, which require greater resistance to erosion
than elsewhere.
The success or failure of gully erosion control activities depends on how they are selected and
designed appropriately for each situation, and constructed consistent with established guidelines.
Given the large extent of gullies in the relatively low intensity of land use in grazing areas, cost
effective gully erosion control relies on low cost measures applied to many gullies.
1.3 Programme strategy
The gully erosion control strategy is to fence around gullies to enable vegetation to grow with
negligible or only light grazing pressure, and to manage forage utilisation and vegetation in the gully
catchment to help reduce runoff (Order 1 activities in Table 1, these are normally essential activities
at any site). Revegetation activities (e.g., seeding, planting) and porous check-dams to slow runoff
within gully channels and assist revegetation, are next (Order 2). If gully fencing removes stock
access to water then off stream water points are required (Order 2). If roads or tracks are the main
source of runoff, drainage management may be required (Order 2). Engineering activities in gullies
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(Order 3) should be used only if relevant activities in lower orders are also applied and there are
special needs at a site. Following this order, more costly gully erosion control activities are supported
by lower level activities to increase their effectiveness and to reduce their risk of failure. In short, “all
structural measures must be accompanied with vegetative measures” (Geyik, 1986).
Table 1. Relative effectiveness of gully erosion control activities at reducing sediment yield from the gully head, wall and
channel, addressing the 3 principles in Figure 2. Greater effectiveness is indicated by more ticks. Individual treatments
with relatively higher unit costs are indicated by more $. Order 1 activities should be applied at all sites, Order 2
activities are applied only when relevant Order 1 activities are also applied. Any order 3 activities require relevant Order
1 and 2 activities. The control activities are described in detail in Section 3.
Control activity
Head
Wall
Channel Cost
Order
Fence around gully and control stock access
√
√
$
1
Porous check-dams and fence
√
√√
$$
2
Revegetate gully and fence
√√
√
$$
2
√
√√
$$$$
3
√√
n/a
1
Retain native woody vegetation in gully catchment
√√
n/a
1
Fire management to retain species composition A
√
n/a
1
√
$$$
2
√√
$$$
2
Engineered grade control structures and fence
Low forage utilisation in gully catchment
A
Off-stream water point to reduce grazing pressure at gully
Manage road and fence line drainage and fence
A
A
Runoff diversion bank or contour ripping and fence
√√
$$$
2
Gully head drop structure
√√√
$$$$
3
Reshape, revegetation
√√√
$$$$
3
A Cost
assumes co-investment
Assisting revegetation is the main focus of the Gully Erosion Control Programme due to its low cost
and ability to be applied over large areas, and because it addresses the root cause of gully erosion.
Rather than focusing investment on intensive management such as reshaping gullies at a few sites, a
larger impact on catchment sediment loads can be achieved by investing in fencing to protect gullied
and vulnerable areas from grazing at many sites, installing low cost porous check dams to assist
vegetation recovery in the gully channel, and revegetating gullied areas. These are low-cost
measures which can be applied across large areas. Worked examples given in Sections 3.2 and 3.9,
and Table 3, indicate that revegetation of gully features including porous check-dams is
approximately one-third the cost per hectare, and sediment saving in tonnes per year (t/y), of
mechanical reshaping, indicating that three times (and possibly more) the erosion area can be
treated with lower cost activities.
The revegetation approach also helps to integrate gully erosion control with grazing land
management, including forage management in areas draining to gullies, which is important for the
long-term sustainability of gully erosion control.
Where more costly measures such as mechanical/engineering options are planned they must be
justified in terms of the fine sediment they save, e.g. $ per tonne of sediment abated per year. Note
Estimating the cost-effectiveness of engineering approaches should consider the risk of their
pronounced failure in large runoff events. Order 1 and 2 activities can be applied in all soil types, but
8
the design and implementation of activities involving earthworks must carefully consider soil
erodibility.
2 Spatial patterns in gully extent
A recent data synthesis identified priority areas in the GBR catchments in which gully erosion
contributes high levels of fine sediment to the GBR lagoon (Wilkinson et al., 2015). The Gully Erosion
Control Programme uses this knowledge base and other information to focus activities within 10 of
the 47 GBR catchment management units (see Programme Guidelines, spatial data on website and
Figure 3). Gully erosion in these 10 units contributes more than half of the fine sediment export
contributed from gully erosion across all GBR catchments. These units are primarily closer to the
coast where rainfall and erosion rates are higher. They are also well-connected through the river
network to the coast, so that the effect of erosion control on sediment export to the GBR lagoon will
not be attenuated by deposition processes occurring in large dams or floodplains downstream of
project sites.
Within each of the 10 priority management units, spatial patterns in gully extent should be
considered when selecting and designing gully erosion control activities. Areas with more extensive
gully erosion may be more cost-effective to treat if, for example, each kilometre of fencing can
control stock access to a larger area or length of gully erosion. Therefore, project sites should be
targeted within each management unit towards areas with higher levels of gully density to increase
their cost-effectiveness. The nature of gully erosion control works required may also be different in
areas with large extents of gully erosion.
Gully extent has been mapped across the priority management units from air photos, and in some
units by erosion modelling (Figure 3 and Appendix A; spatial data are available on request to Reef
Trust). Contrasts in mapping methods are evident between management units, and this mapping is
not used to allocate funds between management units. Gully sediment loss is affected by gully size
and erosion rate as well as gully extent. However, the gully extent mapping is useful for planning
gully erosion control activities within each management unit, enabling activities to be targeted to
areas of higher density where gully fencing can be more efficient in terms of containing larger
lengths and areas of gully erosion per kilometre of fence. Project planning at the site scale should
also consider gully characteristics and erosion rates as described in Section 4.
Prevention of gullies in non-gullied areas is also important, especially in soil types with duplex
profiles, such as Chromosols (red goldfields) and Sodosols (“spewy” soils with yellow/brown
subsurface clay). These soils have high clay content in the subsoil which limits infiltration, leading to
more frequent saturation of the soil surface, and surface runoff. Avoiding gully erosion in areas with
sodic subsoils is also very important because once these subsoils are exposed they are very difficult
to stabilise.
9
Figure 3 The density of gullies for catchments draining to the GBR lagoon. Catchment management units are labelled and
outlined in black. The ten management units in the Reef Trust Gully Erosion Control Programme are outlined in blue.
Variation is evident between management units in the methods for mapping gully density, and this mapping is not used
to allocate funds between management units. The gully density data sources in each unit are: Normanby (Brooks et al.,
2013); Bowen/Bogie and East Burdekin (Tindall et al., 2014) ©Copyright The State of Queensland, Lower Burdekin, Don,
Isaac and Mary (Darr et al., © Copyright DNRM unpublished data), Theresa Creek, Mackenzie, Fitzroy (Trevithick et al.,
2009) © Copyright The State of Queenland, remaining units (Hughes et al., 2001; NLWRA, 2001). In some management
units data were converted from original mapping units to km/km2 based on estimated gully widths. Please note: spatial
data can be downloaded from the website.
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3 Gully erosion control activities
Key features of the main gully erosion control activities listed in Table 1 are described below.
Applicants/Delivery Partners are encouraged to also consult other recent references on gully erosion
control in Queensland including Carey et al. (2015) and Shellberg and Brooks (2013). Gully erosion
control activities other than the ones described may be utilised provided they address the objectives
described in Section 1.2, and their application can be demonstrated to be cost-effective.
All activities should be undertaken with care for safety and Work Health and Safety obligations in
mind.
3.1 Fencing
Cost: low – many gullies
treated
Risks: Low – may fail if grazing
pressure in gullies remains
high
Cost effectiveness for
sediment: high - many gullies
treated
3.1.1 Objective
To enable the area in and around the gully to be managed primarily for erosion control rather than
livestock production, with short periods of dry-season grazing only as required to manage fire risk or
vegetation composition. This will enable native perennial vegetation to develop a high biomass
which helps in resisting erosion and sediment transport, in keeping the soil drier and in reinforcing
the soil with plant roots.
Fencing should be used at all gully erosion control sites. Fencing is essential to protect active or
passive revegetation of gullies, since livestock will preferentially select new vegetation growth.
Cattle access also causes physical disturbance of the soil through hoof compaction or by dislodging
soil particles.
Fencing around gullies is a more reliable approach to gully erosion control than managing grazing
pressure in large paddocks containing gullies because;
1. Gullies require higher levels of vegetation biomass than other areas of the landscape
because the resistance of incised gully walls and channels to erosion is much lower than the
surrounding areas for the reasons listed below:
a. Gully walls have higher gradients than hillslope surfaces, reducing soil stability and
increasing runoff energy;
b. Soil around gullies is weakened by being saturated more frequently and for longer
than higher in the landscape;
c. Gullies are exposed to much higher runoff volumes and shear stresses due to
concentration of surface runoff from the hillslope area above.
2. Degraded areas like gullies are preferentially grazed. The small amount of grass which grows
in degraded areas like gullies is ‘fertilised’ by mineralisation of particulate nutrients
associated with the erosion process, making it more attractive to cattle and perpetuating the
erosion process.
3. If gullies are contained within larger paddocks it is easy for management of grazing pressure
on the gullies to drift away from sustainable levels which require stocking rate adjustments
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to match seasonal conditions. In contrast, once gullies are fenced, and provided fences are
maintained, conscious decisions are required to graze these areas.
Gully fencing is more efficient and cost-effective if multiple gullies can be included within the fence
so that the length and area of gullies within the fence is increased relative to the length of the fence.
3.1.2 Integration with other fencing requirements
Gully fencing can assist grazing land management by;



excluding cattle from gullies because they complicate mustering;
providing the infrastructure to better manage grazing timing and pressure within smaller
paddocks to improve the condition and appearance of the property; and
rehabilitating areas of active erosion.
Integrating gully fencing with riparian fencing makes good sense since gullies are usually connected
to streams. The key is to control grazing pressure on gullies and other incised surface drainage lines
that are more vulnerable to erosion, separately from flatter areas where vegetation is more stable.
Because gullies require much lower grazing pressure than non-gullied areas, it is ideal if fencing can
be designed to make it unnecessary to graze the gullied area except for short periods to help
manage fire risk. Rotational grazing of gullied areas, such as in smaller ‘frontage’ paddocks, may not
provide sufficient protection from grazing pressure unless carefully managed to maintain complete
ground cover.
Where linear branching gullies are extensive across entire paddocks (e.g., gully spacing of <500m) it
may not be feasible to fence around all gullies. In this scenario the downstream parts of gullies may
be lumped within a ‘riparian’ fence, with spur (or branch line) fences between gullies to keep stock
tracks away from gullies.
Gully fencing may assist efforts to achieve paddock subdivision. Areas draining into gullies need wet
season spelling and careful management of grazing pressure to improve perennial pasture
composition and soil health and thus to reduce runoff. Paddock subdivision may help to achieve this.
If it is feasible to design the layout of gully fencing to help achieve paddock subdivision, landholder
co-investment may be more likely.
3.1.3 Specifications
Set the fence back at least 5 m from the gully edge (at least 10 m from gullies deeper than 3m). Do
not make the fenced area so large that it becomes used for routine grazing. Use at least a 20 m setback around the gully head and side branches to allow for ongoing erosion and to encompass
erosion-prone areas such as scalds. Ensure that the fence encloses all areas where other gully
erosion control activities are undertaken.
Ensure that the fence is sound enough to prevent livestock entry even when forage biomass in and
around the gully is much higher than in the paddock. Prevent livestock access at the downstream
end with a secure flood gate if the fence crosses the gully channel.
Felling trees or disturbing ground vegetation to erect the fence should be kept to the absolute
minimum required to access the site by vehicle and erect the fence. Do not undertake earthworks or
disturb the ground vegetation cover other than as required to access the site.
12
There is a benefit to landholder involvement in fence construction if it helps to encourage stock
exclusion and fence maintenance.
3.2 Porous checkdams
Cost: Low-Medium, many
gullies treated
Risks: Low - not effective
where runoff volumes are
large
Cost effectiveness for
sediment reduction: Good
3.2.1 Functional Objective
To slow the flow of water in the base of gullies, and improve soil condition by causing deposition of
fine sediment, nutrients and seeds. This assists germination of available seeds from perennial
grasses, shrubs and trees, leading to a higher biomass of native vegetation in the gully floors (and in
the longer term a higher diversity). Once established, vegetation enhances sediment deposition to
reduce gully sediment yield, leading to gradual gully infilling in the very long term.
Typically gully floor sediment deposits have a very small proportion by weight of silt and clay
particles (Bartley et al., 2007), making them too dry, unstable and nutrient poor to sustain much
vegetation apart from weeds which tend to die off during droughts (Wilkinson et al., 2013). In other
situations gully floor sediments can also become hard-set due to rainsplash.
Porous check dams (sometimes called leaky weirs) work by slowing the water flow during runoff,
rather than by permanently damming water. Debris accumulates on the upstream side of the checkdam increasing the structure’s ability to slow the flow.
Porous check-dams have been widely used in gully management both worldwide and in Australia,
and have been successfully trialled in the catchments of the GBR (Wilkinson et al., 2013).
3.2.2 Construction
Porous check dams are simple to construct and use materials from near the gully. Consequently they
are cheap to build – enabling many gullies to be treated for a modest budget.
Material that needs to be purchased are: flexible wire mesh with 100 millimetre square openings,
star pickets for anchoring to the base of the gully and some fencing wire.
Materials that are sourced from the site are: fallen timber (branches and shrubs) and or rocks. The
check dam timber should persist long enough for vegetation to become established and decompose
over time.
If rocks are used, the average size of rocks should be 10-20 cm. The rocks should be of mixed sizes
with minimal rock smaller than 5cm.
13
Figure 4. These check dams are 500 mm high, built from fallen timber. The catchment area of this gully is 2 hectares
(photo looking downstream). From (Wilkinson et al., 2013). Each structure took 2 people an hour to construct.
Keep the height of each check dam low (<0.6m), because that is sufficient to trap soil for
revegetation. Also the hydraulic forces increase with height, increasing the chance of failure by
scouring under or around the structure. It is far preferable to have many small check dams in a gully
than a few large check dams that may fail.
The check dam crest should be higher at the sides of the gully to divert higher flow velocities away
from the gully walls and prevent scour around the end of the check-dam. Where gully walls are
sloping this can be achieved by continuing the check-dam some way up the gully walls.
Construction of porous check dams with fallen timber is commenced by laying the metal mesh
across the base of the gully. Sheets are overlapped and joined with fencing wire. The ends of the
mesh are positioned so that the completed structure will be firmly against the gully wall. The fallen
timber or rocks are them piled in a sausage-like manner along the mesh. The mesh is then closed
over the timber or rocks and secured with fencing wire. Finally, star pickets are driven through the
centre of the barrier at approximately 2 metre intervals, to anchor the check dam to the base of the
gully.
Moving the material to the site should be done by hand or with small machines. The use of large
machines such as excavators should be avoided or minimised due to soil disturbance leading to
more gully erosion, or bringing in weed seeds.
If using rock, or for larger gully catchment areas and runoff volumes (assuming the gully slope is flat
enough that check-dams will enable fine sediment deposition), consider keying check-dams into the
gully sidewalls, and using rock to construct energy dissipating aprons on the gully floor downstream
of each check-dam.
In sodic soil consider reducing the check-dam height and spacing and increasing the porosity to avoid
outflanking.
14
Note that the materials suggested above are much more preferable than the geotextile (weed mat)
barriers (or sand bags) used for temporary erosion control on construction sites.
3.2.3 Placement
The check dams should be spaced along the gully channel close enough so that the crest of each
check dam is no higher or slightly below the elevation of the crest of the next check-dam
downstream (Figure 5). For example in a gully with bed slope of 0.02 (2 percent), check-dams of 0.5
m height will be spaced no further apart than 25 m (slope = check-dam height / max spacing).
Figure 5. Porous check dam arrangement in longitudinal section. Runoff is slowed such that some fine sediment and
seeds are deposited upstream (to the right) of each check-dam, improving the moisture and nutrient status. To prevent
scour downstream of check-dams ensure they are spaced so the crest of each check-dam is at least as high as the base
(toe) of the next one upstream. Reproduced from Berton (1989), cited in Critchley and Siegert (1991).
Install check-dams in the following places:



Along the main channel and side-branches of the gully
Down the gully until the catchment area of the downstream check-dam has an upstream
catchment area approximately 2 ha, or larger in flatter landscapes. At larger catchment
areas the runoff volumes become too large for deposition to occur.
Not in the steeper section of gullies immediately downstream of the headcut, where the
steeper channel slope leads to smaller check dam spacing, and the gully channel is narrower
giving higher runoff velocity.
Porous check dams should be used in combination with the fencing out of gullies, to allow
vegetation to become established in the gully.
3.2.4 Design example
An example of costing the application of check-dams and fencing to a large gully is outlined in Table
3 (Gully ID1). The estimated cost assumes fencing completely around the gully at $5,000 per km, plus
installation of 300 porous check-dams at a spacing of 15m over 4,500 m of linear drainage line within
the feature. An additional $20,000 is estimated for site preparation, for sourcing additional materials
and for revegetation.
3.3 Revegetation in and around gullies
Cost: Low-Medium depending
on techniques
Risks: Establishing vegetation
in a variable climate
Cost effectiveness for
sediment reduction: Good
3.3.1 Objective
Active revegetation may not be required where native trees, shrubs and grasses occur upslope to
provide seeds, but is worthwhile in areas where natural vegetation has been removed or cannot be
expected to recover.
15
The objectives of revegetation are to establish a self-maintaining system which protects the soil
surface from rainsplash, slows down runoff by obstructing flow and roughening the surface,
increases soil strength by reinforcing the soil with roots and moderating soil moisture, and reduces
surface runoff by evaporation and transpiration from the leaves. Organic litter will help to improve
the soil health over time.
3.3.2 Specifications
Local professional advice should be sought for revegetation species and techniques. Typically a
diversity of grasses, shrubs and trees will provide the best mix of functions in the long term.
Perennial tussock grasses provide good erosion control, particularly species with large basal area and
root mass (Shellberg and Brooks, 2013). Woody stem densities should be low enough to allow grass
growth. Species native to the local area should be used wherever feasible.
The response to revegetation will be more vigorous in more fertile and structured soils. Deep ripping
along the contour can assist root penetration for new plants and retaining surface runoff but should
not be done directly adjacent to gullies, especially where the subsoil slakes or disperses readily in
water. Surface ploughing near gullies is risky because of the soil exposure and minimal effect on
runoff.
Revegetating exposed sodic soils which are strongly dispersive on contact with water is assisted by
providing an initial cover of compost and/or non-dispersive topsoil, and by chemically treating with
gypsum to support initial vegetation establishment (Shellberg and Brooks, 2013; Carey, 2014).
Seeding directly with rapid-growing grasses is a cheaper alternative which can also be somewhat
effective for revegetating sodic soils. Note that soil sodicity varies from slight to strong and different
approaches may work in different situations.
Weed control, such as by mulching or weed mat can be important to allow vegetation to establish.
Revegetation should be protected from livestock for at least the first 3 years or until plants are large
enough to survive grazing.
Consider seeking landholder co-investment especially if seeding outside the gully-exclusion fence or
seeding with pasture grasses.
3.4 Forage management of paddocks draining to gullies
Cost: Very low; training cost
only.
Risks: No control on stocking
rates after project is complete
Cost effectiveness for
sediment reduction: Good
This activity is used in paddocks draining into gullies to support fencing, porous check-dams and
revegetation at gully erosion control sites. It should be used where gully fencing does not cover the
entire gully catchment. It will involve training and extension activities as required to support the
legacy of revegetation and fencing activities at project sites. Training may also involve graziers
additional to the site landholders where that helps to achieve Programme objectives.
Training should focus on setting stocking rates based on a forage budget that limits the utilisation of
forage by livestock to less than 25% of the annual herbage growth, a level which is sustainable for
16
sustaining the perennial composition of forage on most land types (Hunt et al., 2014), and also wet
season spelling. Available resources include:




Grazing BMP modules for Grazing Land Management and Soil Health
(www.bmpgrazing.com.au);
Stocktake phone app and software (http://www.stocktakeplus.com.au/);
FutureBeef website https://futurebeef.com.au/resources/multimedia/#GLM;
Meat & Livestock Australia Edge network Grazing Land Management course.
3.5 Water points
Cost: Medium – depends on
piping distance required
Risks: Unlikely to reduce
grazing pressure sufficiently
unless gully is fenced out.
Cost effectiveness for
sediment reduction: LowMedium
Stock watering points are best positioned on hills or ridges so that stock tracks lead away from these
higher parts of the landscape. Having watering points low in the landscapes including sites adjacent
to gullies, leads to stock tracks near and through gullies which increase erosion rates and hampers
other rehabilitation measures.
Moving watering points to more favourable locations is a relatively expensive measure. In this
programme, a typical reason to install a water point will be where new gully fencing prevents access
to what was previously the only perennial water in the paddock. Otherwise, caution must be
exercised in implementing this activity as simply adding watering points can result in an increase in
stock numbers and continued run down of pastures over time, which can exacerbate land
degradation and gully erosion. Additional water points can potentially also attract more native
grazing animals.
3.6 Contour banks and diversion banks
Cost: Medium – only treat
active gullies which cannot be
stabilised without diverting
runoff
Risks: Caution in use of heavy
machinery – may damage
catchment vegetation, and
exacerbate erosion if
incorrectly designed.
Cost effectiveness for
sediment reduction: Medium
The aim of contour and diversion banks is to divert run-off away from gully heads and into natural
waterways or stable areas which are not susceptible to erosion (Geyik, 1986). However, there is a
risk of starting a new gully where the water is diverted (Carey et al., 2015). Excessive surface runoff
is often indicative of over-grazing, either historically or currently. Revegetation and controlling
grazing pressure are cheaper activities which address the cause of excess surface runoff, and which
support commitment to responsible long term management.
Diversion banks or detention structures, together with their runoff discharge areas, should be
included inside the gully fencing so that they can be managed at high biomass to maximise water
infiltration.
17
Ripping along the contours is an alternative to formed diversion banks and can reduce runoff for a
number of years to (alongside spelling) assist revegetation of the gully catchment. This activity
should be used with caution and kept at least 50 m away from existing gullies.
Soil disturbance has a risk of creating further gully erosion, particularly in erodible soil types.
3.7 Managing road and track drainage
Cost: Medium – only treat
active gullies where runoff
dominated by road drainage
Risks: Caution in use of heavy
machinery – may expose
erodible subsoils, and
exacerbate erosion if
incorrectly designed.
Cost effectiveness for
sediment reduction: LowMedium depending on coinvestment
Roads, tracks and other compacted areas of soil are known to produce high levels of runoff.
Carefully designed drainage of these surfaces can contribute to both reducing concentrated flows
reaching existing gullies and minimise the chances of new gullies forming. Road drainage takes
several forms including culvert pipes, cross drains (also locally called speed bump or “whoa boys”)
and road crowning. The use of closely spaced drainage (typically every 20 to 50 metres) along a road
results in non-erosive overland flow from roads.
Road drainage is relatively expensive and should be considered only where runoff into active gullies
is dominated by road drainage. Where maintenance of road drainage provides a private benefit a coinvestment from the landholder should be considered.
Soil disturbance has a risk of creating further gully erosion, particularly in erodible soil types.
3.8 Grade control and gully head drop structures
Cost: high – only treat gullies
threatening infrastructure
Risks: Caution in use of heavy
machinery – may destabilise
gully
Cost effectiveness for
sediment reduction: low
3.8.1 Objectives
Grade control structures and rock chute drop structures at the gully head can save sediment that
would be lost with the continued upslope movement of a headcut or secondary incision of a channel
bed to a larger depth than before.
However, these measures are relatively expensive, and are only used when other options such as
porous check dams are inappropriate due to the gully size and rate of expansion. In the wrong place
or in mature gullies they are very expensive and a poor option in terms of cost effectiveness. They
can be justified in situations where a gully is threatening a structure such as a road or pipeline; coinvestment is recommended in such cases. Lower-cost activities are preferred for controlling gully
erosion over extensive areas.
3.8.2 Specifications
Use of grade control structures requires specialist design and construction. As gullies are frequently
associated with sodic and dispersive soils, an assessment of the likelihood of failure of the structure
18
as a result of dispersion of the adjacent soil is required. Out-flanking or scouring around structures
by runoff is a common mode of failure. Fencing during and after construction is essential. The use of
heavy machinery in construction may result in disturbance of the gully and its immediate surrounds
thus introducing new risks of gully erosion.
Design guides for grade control structures are available (e.g., Geyik, 1986); Section II. Basic Gully
Treatment Measures.
Figure 6. A grade control structure under construction in southern Queensland in 2013. Approximate cost $22 000.
[photograph ©Condamine Alliance]
Figure 7. A rock chute – approximate cost $11 000 [photograph ©Condamine Alliance]
3.9 Gully reshaping
Cost: high – only treat gullies
threatening infrastructure
Risks: Heavy machinery may
destabilise gully. Requires
rapid revegetation.
Cost effectiveness for
sediment reduction: low
Reshaping of gullies into evenly-sloping areas (batters) can appear to provide immediate control of
sediment loss, but requires skilled design and is very expensive per unit area. It is also dependent on
successful control of surface runoff and revegetation. Reshaping may assist in establishing
vegetation on sodic soils, provided immediate surface cover is provided from organic mulch
(Shellberg and Brooks, 2013). Chemical treatment of sodic soils (e.g., with gypsum) may also be
19
temporarily required if they are exposed in the reshaped area. The reshaped area will be more
steeply sloping than the natural surface, and hence more vulnerable to erosion than the surrounding
natural surface. In order to maintain the integrity of the reshaped area, it should not be used for
conventional grazing, and ongoing control of stock access is required by secure fencing.
Reshaping has a relatively high cost per unit area (e.g., Shellberg and Brooks (2013) estimated
$10,000–$30,000 per ha). Soil disturbance has a risk of creating further gully erosion, particularly in
erodible soil types. Some erosion of the area following reshaping can be expected. Gully reshaping
has a risk of failure, for example severe rainfall in the recovery period can initiate re-incision of the
reshaped area.
Reshaping must be implemented only in combination with other gully erosion control activities: “In
regions with heavy rains, filling, shaping and diversions alone will not suffice to control gullies.
Additional gully control and slope stabilization measures, such as check dams and revegetation
should be undertaken” (Geyik, 1986).
Example
An example of design and costing reshaping of a gully is given in Table 3 (Gully ID2). The cost is based
on $15,000 per ha as estimated for mechanical reshaping followed by applying gypsum, locally
available compost and hand sown grass seed (Shellberg and Brooks, 2013). Additional design costs
may be incurred where specialist expertise is required. Relative to revegetation of the existing
topography, the immediate site outcome is more transformational and the reduction in yield may be
more rapid. However, extreme rainfall may cause the works to fail. However, in this example
reshaping is less cost-effective than revegetation of the existing topography including porous checkdams.
4 Monitoring and Reporting
4.1 Objectives
An essential part of the Project Activities is to report the characteristics of gullies at project sites, the
gully erosion control activities implemented, and to monitor the environmental impact in local
conditions. Monitoring and Reporting in the Programme has several objectives:
1. To measure and report the characteristics of gullies at project sites, and the selection and
design of gully erosion control activities consistent with the objectives in Section 1.2;
2. To help define the cost-effectiveness of gully erosion control activities at each site in terms
of the past erosion rates, and expected sediment saving from the activities locally and to the
GBR lagoon;
3. To confirm the completion and integrity of on-ground activities;
4. To assess partner and landholder perspectives of gully erosion control works, and inform
decisions on future activities;
5. To inform evaluation of the project impact on vegetation;
6. To facilitate learning between sites, and adaptive management of the project and
Programme in consultation with the Department of the Environment (the Department) and
Technical Partner;
20
7. To assist the Paddock to Reef Monitoring, Modelling and Reporting Programme to estimate
erosion reductions from gully erosion control activities;
8. To provide a baseline for subsequent follow up monitoring to evaluate longer-term
outcomes on land condition and erosion.
Other monitoring activities that may occur outside the project include (i) scaling up monitoring
results to assess regional impacts, and (ii) researchers doing intensive studies of gully erosion control
to verify their effectiveness on erosion and sediment yields and to further refine rehabilitation
techniques.
4.2 Summary of reporting
Delivery Partners are required to report a summary of progress implementing activities (as stated in
the Application Form), every six months. This will be undertaken through the Australian
Government’s Monitoring, Evaluation, Reporting and Improvement Tool (MERIT https://fieldcapture.ala.org.au/). The following content needs to be included with the six monthly
reporting:
1. Progress of activity implementation and achieved outputs, linked to sites and points of
interest (in MERIT), including Table 2;
2. The planned site designs for the coming period and estimated cost-effectiveness as
described in Section 4.3, including Table 3. In the early stages of the project this may also
occur separately to regular reporting dates;
3. Before treatment site monitoring as described in Section 4.4, including Table 5, Table 6 and
the photos which can be attached as a non-public documents in MERIT. In the early stages of
the project this may also occur separately to regular reporting dates;
4. Site monitoring after treatment, including photographs and commentary as described in
Section 4.4, including Table 5, Table 6 and the photos which can be attached as a non-public
documents in MERIT; and
5. On an annual basis, submission of the Master Table spreadsheet and spatial layers of project
area.
21
Treatment
Cost
Effectiveness
($/t/yr)
Est. Sediment
Reduction
(t/yr)
Effectiveness
of Control
(%)
Total
Cost
($)
Total
Gully Area
Treated
Number of sites
Table 2. Summary report of project activities for a six-month period. These totals are to be summed from the Table 3 for
each project site completed.
Fence around gully and
control stock access
Fence around gully and
revegetate
Fence around gully and install
porous check-dams
Water point to reduce grazing
pressure at gully (no fence)
Reduced forage utilisation in
gully catchment to <25%
Manage infrastructure and
fence around gully (e.g. road
drainage)
Runoff diversion bank and
fence around gully
Gully head drop structure and
fence around gully
Engineered grade control
structures and fence
Reshape, revegetation and
fence around gully
Other (specify)
4.3 Site reports on planned activities and before-treatment monitoring
The selection and design of on-ground works at each planned site (e.g., paddock) should be
informed by a site report provided to the Department and Technical Partner as well as the
landholder. The site report should document the following elements:
1. Short description of site context prior to project activities, including;
a. A general sense of the state and known history of the area immediately around the
gully including a description of gully wall soil and steepness, vegetation, and land
surface slope.
b. The context of where it is located relative to property infrastructure, property size
and land type composition, and recent grazing land management.
2. Completion of Table 3 (to be delivered in .xlsx format).
3. Description and objectives of the gully erosion control strategy and specific activities.
22
4. GIS map of the site, ideally mapped over aerial imagery. It may help to first prepare a ‘mud
map’ during the field visit as described in Section 4.4.5. The final GIS map should include:
a. Boundaries of gully erosion features,
b. Watercourses,
c. Existing infrastructure including fencing, road or tracks, stock watering points,
d. Locations of planned fencing, check-dams and other project activities.
e. Monitoring and photo-point locations, as described in Section 4.4.
5. Description of design details (e.g., fencing length and setback at gully sides and head,
number of check dams, dimensions and materials, revegetation methods, hydraulic or other
technical designs, recommended approach to forage management).
6. ‘Before-treatment’ monitoring table and supporting comments, as described in Section 4.4.
7. Budget itemising each erosion control activity and monitoring.
8. Indication of landholder support.
Timing: Once funding agreements are signed, the site report should be provided to the Department
for review within a reasonable timeframe prior to works commencing. Site reports are not required
prior to submission of Programme applications. Following the initial six months, the site reports of
planned works and monitoring should be provided to the Department on a 6 monthly basis, prior to
the next period of implementation.
23
Gully ID 1
Gully ID 2
Site Design Template
21/9/15
21/9/15
S Wilkinson
S Wilkinson
Include in all
reports
Include in all
reports
Longitude (decimal degrees) A
Include in all
reports
Include in all
reports
Property name A
Include in all
reports
Include in all
reports
Paddock name A
Include in all
reports
Include in all
reports
470
470
240
240
11
11
2
2
12
12
564
564
0.024
0.024
63
63
Soil: Type
Sodosol
Sodosol
Soil: Subsoil slake test (stable/slakes/dispersive)
Dispersive
Dispersive
Soil: Estimated dry bulk density (t/m3)
1.5
1.5
Soil: Estimated subsoil silt + clay (proportion)
0.5
0.5
846
846
3, 5
5, 10
0.5
0.5
423
423
Total cost of gully erosion control activities ($)
57,100
169,200
Cost-effectiveness ($ per t/y)
135
400
Date
Person completing the report
Latitude (decimal degrees)
A
Gully: Length (m) B
Gully: Width (m)
B
Gully: Area (ha) B
Gully: Depth below the head (m)
C
Gully: Maximum depth (m)
Gully: Growth rate average over >10y (m2/y)
B
Gully: Longitudinal slope (proportion)
Gully: Catchment area above the head (ha)
D
Yield: Estimated historical fine sediment yield (t/y)
Gully erosion control activities
F
Gully control effectiveness (proportion)
Total Suspended Sediment saving (t/y)
F
G
E
Gully ID 3
Table 3. Site design table. This table can be implemented in a spreadsheet for calculating the cost-effectiveness
(available on request). The completed examples are discussed in Section 3.2 and Section 3.9, respectively.
A These
parameters should be included in site reports. Actual values are not included in this example (which is a real gully in
the Bowen River catchment) because this is a public report rather than a project site report.
B
Estimate from historical air photos and Google Earth. Gully Length is the longest overall dimension of the gully, and Width
is the average width measured at right angles to the length, such that Area (ha) = Length (m) × Width (m) / 10,000. If no
data on historical changes in extent can be obtained then assume Growth rate = Gully area × 0.005 (assumes gully age =
100 years and current erosion rate = 50% of the average rate since gully initiation).
C From
monitoring, see Table 5.
D Can
be estimated from aerial imagery if clearly defined, or by mapping the upstream contributing area in GIS using the 1”
Hydrologically Enforced Digital Elevation Model (DEM-H; ANZCW0703014615) (Gallant et al., 2011), available from
http://www.ga.gov.au/scientific-topics/national-location-information/digital-elevation-data
E
Estimated historical fine sediment yield (t y-1) = Gully Head depth (m) × Gully Growth rate (m2/y) × Soil dry bulk density (t
m-3) × Soil proportion of silt + clay. For linear gullies the Growth rate = average extension (m/y) × Gully width (m).
F
From Table 4, or estimated based on the monitoring results from comparable field trials in the area. If a combination of
techniques are used list them, and describe variants in the text.
G
Total Suspended Sediment saving = Estimated fine sediment yield × Gully control effectiveness
24
Table 4. Estimated effectiveness of gully erosion control measures for use in site design in Table 3.
Fence around gully and control stock access
Activity
Number
1
Effectiveness A
0.2
Fence around gully and revegetate
2
0.3
Fence around gully and install porous check-dams
3
0.5
Water point to reduce grazing pressure at gully (no fence)
4
0.05
Stocking rate reduced in gully catchment to <25% forage utilisation
5
0.1 B
Manage infrastructure and fence around gully (e.g. road drainage)
6
0.3 B
Runoff diversion bank and fence around gully
7
0.4 C
Gully head drop structure and fence around gully
8
0.5
Engineered grade control structures and fence
9
0.5
Reshape, revegetation and fence around gully
10
0.5
Other activity
11
specify
Gully erosion control activity
A Expert
B Can
opinion based; for guidance only.
be added to the effectiveness of treatments in the gully
C Accounts
for some increase in erosion below discharge point
4.4 Site monitoring
4.4.1 Principles
Monitoring consists of a simple set of observations and photos that are made at least three times
(before treatment and twice after treatment). The emphasis is on consistency – so that the
evaluation follows the scientific method. Try to be as consistent as possible in making the
observations and taking the photos.
Monitoring design requires the application of some principles of scientific experiments so that
external factors like variability in the weather and stocking rates outside the managed area are
removed from the assessment. For this reason monitoring should use a Before After Control Impact
(BACI) design in which some gullies in each paddock are left untreated for comparison over time,
and both the treated and untreated gullies are monitored before and after the treatment (gully
erosion control activity) is applied. The monitoring is designed to be reasonably rapid to undertake
in the field (~30 minutes for 2 people), and to require limited skills and experience. Formal
comparisons between sites and over time should be performed by specialists.
4.4.2 Timing of monitoring
Each site should ideally be monitored at least three times during the project:
1. Before site activities commence. Ideally this is early in the dry season between March and
May so that results are comparable with later years.
2. Shortly after treatment: For Order 1 activities (Table 1) this will mostly be photo point
measurements, provided treatment occurred within the same dry season as the beforetreatment monitoring. If the activities involved physical revegetation or earthworks, the
effects of this disturbance should be monitored.
25
3. At the end of each subsequent wet season (between March and May) following completion
of gully erosion control activities. Seasonal rainfall predominantly drives gully erosion and
the responses to revegetation activities. Measurement at the end of the wet season is also
ideal to indicate the effectiveness and integrity of remediation activities. Where possible,
also repeating the Landscape Condition Assessments upslope of the gully late in the dry
season (between September and November) will capture the lowest functional state for the
season to provide context for measuring recovery.
o
For sites where gully erosion control activities occur in 2016, this will involve
monitoring in both 2017 and 2018. Applications may identify savings which would be
made if only one wet season was monitored after treatment.
4.4.3 Monitoring design
In each paddock that gully erosion control works are planned and undertaken, at least one gully
should be monitored, which is/are typical of all the gullies treated. At least one comparable gully
feature, or part of the gully if there is only one feature, should be left untreated and also monitored
using the same protocol as for the treated gullies.
The standard monitoring design includes:
1. Land Condition Assessments (LCAs) immediately upslope of the gully head, and in the
paddock outside the planned fence location. The method is described in the Stocktake users
guide (http://www.stocktakeplus.com.au/wp-content/uploads/2013/01/Stocktake-usersmanual.pdf). A mobile application for field data collection is available for smartphones and
tablets. Online tutorials are available.
2. Gully head location relative to a permanent reference marker, to enable the erosion rate
between monitoring dates to be estimated.
3. Vegetation cover and photos at five marked sampling locations within or around the gully,
coinciding with gully erosion control activities such as check-dams and contour banks. The
furthest upslope and downslope of structural activities must be included and an additional
three other locations in between. This sample-of-5 approach is used instead of monitoring
every individual structure, to reduce field collection time where multiple treatments (such as
check dams) are installed. The same five monitoring locations are used at each date of
monitoring.
4. Rainfall in the last 12 months.
5. Landholder perspectives of the project activities, including the Water Quality Risk
Benchmarking questions (with the landholder).
6. Annual completion of the Australian Government Reef Master spreadsheet.
Monitoring should be recorded, and subsequently reported, using the template and instructions
below (Table 5). The table can be used for recording comments at the site by cross-referencing from
each comment field (using A, B, C, etc) to comments written on a separate sheet.
26
Gully ID 3
Monitoring Report Template
Gully ID 2
Gully ID 1
Table 5. Monitoring report template (refer to the footnotes which continue over the page).
Property name
Paddock name
Date of monitoring
Name of Observer
Treatment (T) or Control (C) gully
Before (B) or After (A) Treatment
LCA (Land Cond. Ass.) outside Fence: Ground cover (%) A
LCA outside Fence: Pasture condition (1-4) B
LCA outside Fence: Soil condition (1-5) C
LCA above Gully Head: Ground cover (%) A
LCA above Gully Head: Pasture condition (1-4) B
LCA above Gully Head: Soil condition (1-5) C
Gully head distance to reference marker (m) D
Gully head depth (m) E
Fence Integrity (1-3) F
Gully location #1 feature G
Gully location #1 integrity (1-3) F
Gully location #1 cover upstream (%) H
Gully location #1 comment I
Gully location #2 feature G
Gully location #2 integrity (1-3) F
Gully location #2 cover upstream (%) H
Gully location #2 comment
Gully location #3 feature G
Gully location #3 integrity (1-3) F
Gully location #3 cover upstream (%) H
Gully location #3 comment I
Gully location #4 feature G
Gully location #4 integrity (1-3) F
Gully location #4 cover upstream (%) H
Gully location #4 comment I
Gully location #5 feature G
Gully location #5 integrity (1-3) F
Gully location #5 cover upstream (%) H
Gully location #5 comment I
Rainfall in last wet season (mm) J
Landholder perception of activities (1-5) K
Landholder comments about the project activities L
A
Estimate the average percent cover of grass over the area upslope of the gully head, or the planned/installed gully fence
upslope of the gully head.
B
1 = >80% 3P, 2 = 60–80% 3P, 3 = 10–60% 3P, 4 = <10% 3P (refer to Stocktake user guide
http://www.stocktakeplus.com.au/resources/)
27
C
1 = Stable, 2 = Slight disturbance, 3 = Moderate disturbance, 4 = Severe disturbance, 5 = Very Severe disturbance
D
Measure the distance from the nearest part of the gully head to a permanent marker (stake) installed ~20 m upslope.
E
Measure the vertical distance between the natural land surface to the floor of the gully channel 10 m downstream
of the gully head.
F1
= Fully intact, 2 = Signs of potential failure, 3 = Total failure. Measure integrity relative to the objective of the activity (eg
for a fence this is excluding livestock, for a check dam this is slowing runoff to deposit fine sediment and seeds)
G In
a treated gully the feature can be an activity 1 - 11 (See Table 4). Location #1 should be the most upstream (or upslope
if above the gully) project activity, inside the gully fence if installed. In a treated gully it should be at the most upstream
activity (eg porous check-dam or contour bank) if installed. Location #5 should be inside the gully near the downstream
end. In a treated gully it should be at the most downstream project activity inside the gully fence (eg porous check-dam).
Locations #2 - #4 should be inside the gully spaced evenly between #1 and #5. In a control gully, Location #1 should be 10
m below the gully head, Location #5 should be at a location comparable to the distance below the head of treated
Locations #5, and Locations #2 - #4 should be inside the gully spaced evenly between #1 and #5.
H
Estimate the percent cover of vegetation within 1m2 area upslope or upstream at or in line with the centre of the gully
channel
I e.g.,
“this location has recently had runoff”, “grass showing the effects of fire”, “Indian Couch only”, “lots of cowpats”,
“soil is more compacted here than at the planned fenceline.”
J Use
the nearest Bureau of Meteorology gauge or reliable station records
K1
= Completely supportive, 2 = Somewhat supportive, 3 = Neither supportive or unsupportive, 3 = Somewhat
unsupportive, 5 = Completely unsupportive.
L e.g.,
Describe how the project activities have impacted on grazing land management by the landholder.
4.4.4 Photography to support monitoring
Photography is an important monitoring technique, provided the photo point locations and camera
heights are consistent between dates. Key points:
1. For linear features which span the gully channel, the photo point should be on one side of
the gully, with the photo taken looking in the cross-gully direction, along the length of the
feature.
2. A 1.8 m metal star picket (stake) should be driven in at each photo point, to provide a
permanent marker of sufficient height for the photo point.
3. The camera can be placed on the top of the photo point stake to achieve a consistent field of
view.
4. The entire feature being monitored (e.g. gully head, check dam) should be contained within
the frame of the photo.
5. The photo file formats should be *.jpg.
6. Resolution should be high so that a typical photo file is >3 Megabytes.
The locations for site monitoring photographs are listed in Table 6. This table can be used at the site
as a checklist to tick off photo locations completed. Subsequently, it should be used to index photo
filenames for reporting.
28
Gully ID 3
Photopoint field checklist, and filename report
Gully ID 2
Gully ID 1
Table 6 Site monitoring photograph index.
Property name
Paddock name
Date
Name of Photographer
Fence line: upslope
Fence line: along fence
Fence line: ground
Gully head: upslope
Gully head: downslope
Gully head: ground
Gully head: from side
Gully location #1: along feature
Gully location #1: oblique upstream 45 degrees
Gully location #1: oblique downstream 45 degrees
Gully location #2: along feature
Gully location #2: oblique upstream 45 degrees
Gully location #2: oblique downstream 45 degrees
Gully location #3: along feature
Gully location #3: oblique upstream 45 degrees
Gully location #3: oblique downstream 45 degrees
Gully location #4: along feature
Gully location #4: oblique upstream 45 degrees
Gully location #4: oblique downstream 45 degrees
Gully location #5: along feature
Gully location #5: oblique upstream 45 degrees
Gully location #5: oblique downstream 45 degrees
General photos (add description and comments)
4.4.5 Mapping out erosion control activities and monitoring at the site
Monitoring locations listed in Table 5 should be included and labelled on the GIS map of site
activities. Recording GPS co-ordinates of each location may assist this process.
29
Drawing a ‘mud map’ while at the site drafting the activity design and undertaking the before
treatment monitoring (e.g., Figure 8) will assist in the later preparation of a GIS map of monitoring
locations relative to other project activities. Follow the check list of items below to include:









Shape of gully/gullies shown
Overall dimensions of gully shown (length/width/depth)
Height of head cut shown
Locations of existing infrastructure (fencing, roads, tracks, stock watering points)
Location of check dams and other planned activities
Other features located eg erosion features
Monitoring locations as per Table 5.
Location and direction of photo points marked
Annotated comments; e.g., “The walls are near vertical for about 30m below the gully head
with active erosion. Below this point the walls start to slope away and do not show any signs
of slumping.”
30
Figure 8. Example ‘Mud map’ of monitoring locations and on-ground activities for a project site.
31
4.4.6 Reporting site monitoring results
The monitoring report should describe the overall outcome of monitoring for each gully during the
reporting period, supported by the GIS map and >5 example photos. Table 5 should be submitted in
.xlsx format (template can be provided on request). The photo index Table 6 and photo files should
be submitted for reference.
5 Acknowledgements
This report was funded by the Australian Government through the Reef Trust. Comments on draft
versions were provided by Anthea Coggan and Peter Stone (CSIRO), Reef Trust team members,
Michele Barson (DoAWR) and Peter O’Reagain (QDAF).
6 References
Bartley R, Hawdon A, Post DA, Roth CH. 2007. A sediment budget for a grazed semi-arid catchment
in the Burdekin Basin, Australia. Geomorphology, 87: 302-321.
http://dx.doi.org/10.1016/j.geomorph.2006.10.001.
Berton S. 1989. A detailed guide to specifications and use of permeable rock dams in West Africa (in
French). GRET, Paris.
Brooks A, Spencer J, Olley J, Pietsch T, Borombovits D, Curwen G, Shellberg J, Howley C, Gleeson A,
Simon A, Bankhead N, Klimetz D, Eslami-Endargoli L, Bourgeault A. 2013. An empiricallybased sediment budget for the Normanby basin. . Griffith University,
http://www.capeyorkwaterquality.info/downloads.
Carey B. 2014. Understanding dispersive soils. http://landcare.org.au/wpcontent/uploads/2013/01/Understanding-dispersive-soils.pdf.
Carey B, Stone B, Shilton P, Norman P. 2015. Chapter 13 Gully erosion and its control. In: Soil
Conservation Guidelines for Queensland, 3rd Edition. Queensland Department of Science,
Information Technology and Innovation. www.publications.qld.gov.au/dataset/soilconservation-guidelines
Ciesiolka C. 1987. Catchment management in the Nogoa watershed. AWRC Research Project 80/128.
Critchley W, Siegert K. 1991. Water harvesting. FAO.
http://www.fao.org/docrep/u3160e/u3160e00.htm#Contents.
Gallant JC, Wilson N, Dowling TI, Read AM, Inskeep C. 2011. SRTM-derived 1 Second Digital Elevation
Models Version 1.0. Geoscience Australia www.ga.gov.au/topographic-mapping/digitalelevation-data.html.
Geyik MP. 1986. FAO watershed management field manual - Gully control. FAO conservation guide
13/2. Food and Agriculture Organisation of the United Nations.
http://www.fao.org/docrep/006/ad082e/AD082e00.htm#cont.
Gilad U, Denham R, Tindall D. 2012. Gullies, Google Earth and the Great Barrier Reef: A remote
sensing methodology for mapping gullies over extensive areas. In: XXII ISPRS Congress,
International Archives of the Photogrammetry, Remote Sensing and Spatial Information
Sciences, Volume XXXIX-B8.
Hughes AO, Prosser IP, Stevenson J, Scott A, Lu H, Gallant J, Moran C. 2001. Gully erosion mapping
for the National Land and Water Resources Audit. CSIRO Land and Water.
Hunt LP, McIvor JG, Grice AC, Bray SG. 2014. Principles and guidelines for managing cattle grazing in
the grazing lands of northern Australia: stocking rates, pasture resting, prescribed fire,
paddock size and water points – a review. The Rangeland Journal, 36: 105-119.
http://dx.doi.org/10.1071/RJ13070.
NLWRA. 2001. Australian Agriculture Assessment 2001. National Land and Water Resources Audit.
Shellberg J, Brooks A, Spencer J. 2010. Land-use change from indigenous management to cattle
grazing initiates the gullying of alluvial soils in northern Australia. In: 19th World Congress of
32
Soil Science, Soil Solutions for a Changing World, http://www.soilscienceaustralia.com.au,
pp: 3992-3995.
Shellberg JG, Brooks AP. 2013. Alluvial gully prevention and rehabilitation options for reducing
sediment loads in the Normanby catchment and northern Australia. In: Final report for the
Australian Government's Caring for Our Country - Reef Rescue initiative, Griffith University,
Australian Rivers Institute. http://www.capeyorkwaterquality.info/references/cywq-223, pp:
314.
Tindall D, Marchand B, Gilad U, Goodwin N, Denham R, Byer S. 2014. Gully mapping and drivers in
the grazing lands of the Burdekin catchment. RP66G Synthesis Report. Queensland
Department of Science, Information Technology, Innovation and the Arts.
Trevithick R, Herring M, Dougall C, Denham R, Pringle M. 2009. Gully Density Mapping and Modelling
for the Fitzroy Basin, Queensland, Australia. Queensland Department of Natural Resources
and Water.
Wilkinson SN, Bartley R, Hairsine PB, Bui EN, Gregory L, Henderson AE. 2015. Managing gully erosion
as an efficient approach to improving water quality in the Great Barrier Reef lagoon. Report
to the Department of the Environment. CSIRO Land and Water.
https://publications.csiro.au/rpr/download?pid=csiro:EP1410201&dsid=DS6.
Wilkinson SN, Kinsey-Henderson AE, Hawdon AA, Ellis TW, Nicholas DM. 2013. Gully erosion and its
response to grazing practices in the Upper Burdekin catchment. CSIRO Water for a Healthy
Country. https://publications.csiro.au/rpr, pp: 96.
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7 Appendix A – Maps of Gully Density in priority
management units
Please note: Gully density data are available by request from Reef Trust
(reef2050@environment.gov.au) as Geotiff grids (1 km2 resolution). The original gully density data
were of varying resolution. In some units it was of finer resolution than presented here and it may
assist site planning, but should be sourced from the data custodians if required. In the Normanby
Griffith University (Brooks et al., 2013) mapped a subset of gullies as high-resolution polygons. In the
Lower Burdekin, Don, Isaac and Mary; Darr et al., (©Copyright DNRM, unpublished data) mapped
gully presence or absence in 100 m pixels. In East Burdekin and Bowen-Bogie gully presence or
absence was modelled at 5 km pixels (1 km pixels in selected areas), as presented here. In Theresa
Creek, Mackenzie and Fitzroy units gully density was modelled at 1 km2 resolution, as presented
here.
34
Normanby
Figure 9. Density of gully erosion in the Normanby management unit, derived from mapping and sediment budget
modelling sourced from Griffith University (Brooks et al., 2013). Gully density as shown here aggregates mapping of
colluvial and alluvial forms of gully erosion, and also eroding secondary streams, which are included in gully erosion
mapping in other management units. The density of eroding secondary streams relative to gullies was estimated based
on the relative contributions of gully erosion and secondary streams to basin suspended sediment inputs estimated by
Brooks et al. (2013). Density is shown at 1 km2 resolution.
35
Lower Burdekin
Figure 10. Density of gully erosion in the Lower Burdekin management unit, as mapped by Darr et al., (©Copyright
DNRM, unpublished data).
36
Don
Figure 11. Density of gully erosion in the Don management unit, as mapped by Darr et al., (©Copyright DNRM,
unpublished data).
37
East Burdekin
Figure 12. Density of gully erosion in the East Burdekin management unit, as mapped by Gilad et al. (2012) and Tindall
et al. (2014), © Copyright The State of Queensland.
38
Bowen/Bogie
Figure 13. Density of gully erosion in the Bowen/Bogie management unit, as mapped by Gilad et al. (2012) and Tindall et
al. (2014), © Copyright The State of Queensland.
39
Isaac
Figure 14. Density of gully erosion in the Isaac management unit, as mapped by Darr et al., (©Copyright DNRM,
unpublished data).
40
Theresa Creek
Figure 15. Density of gully erosion in the Theresa Creek management unit, as mapped by Trevithick et al. (2009), ©
Copyright The State of Queensland (DNRW).
41
Mackenzie
Figure 16. Density of gully erosion in the Mackenzie management unit, as mapped by Trevithick et al. (2009), ©
Copyright The State of Queensland (DNRW).
42
Fitzroy
Figure 17. Density of gully erosion in the Fitzroy management unit, as mapped by Trevithick et al. (2009), © Copyright
The State of Queensland (DNRW).
43
Mary (1/2)
Figure 18. Density of gully erosion in the Mary River basin / management unit, based on preliminary mapping (as of July
2015) on the western side of the basin by Darr et al., (©Copyright DNRM, unpublished data), and elsewhere by the
mapping of Hughes et al. (2001).
44
Mary (2/2)
Figure 19. Density of gully erosion in the Mary River basin / management unit, based on mapping by Hughes et al.
(2001). This figure is included due to the preliminary status of the DNRM mapping in Figure 18.
45