Year
Tanamerah
Yalliawirra
(S616006)
(S616019)
Salt load
Salt load
kT/year
kT/year
1992
73
125
1993
73
124
1994
48
83
1995
101
148
1996
84
141
1997
49
88
Source: Water and Rivers Commission (2001)
Note: The salt load is related to annual flow and rainfall
in the catchment.
Objective 1
To protect and enhance the quality of the water in
the waterways, lakes and groundwater to meet the
needs of the community and environment.
Baseline knowledge
• Groundwater levels are rising in the Brockman River
catchment, however, as the factors that affect
groundwater recharge and movement within the
weathered rock profile are not uniform, the rate of
groundwater rise is not uniform over the catchment
(Water and Rivers Commission, 2001).
• The annual salt loads exported by the Brockman
River between 1992 and 1997 are listed in table 7.
Tanamerah monitors the upper catchment north of
Bindoon and Yalliawirra is at the confluence of the
Brockman River and the Avon River.
• Sediment loads have increased as evidenced by the
filling of deep pools along the river and sediment
slugs present although no scientific data to quantify
the sediment loads are available.
• Water sampled in July 2000 from the Yalliawirra
gauging station tested below the limits for freshwater
aquatic ecosystems and drinking water guidelines for
common heavy metals (EPA, 1993).
• Total nitrogen (1.1mg/L) and total phosphorus (0.036
mg/L) are also below the target limits for freshwater
aquatic ecosystems (Environment Australia, 2002).
• Total Suspended Solids (32 mg/l) are above the target
limits for aquatic ecosystem protection (Environment
Australia, 2002).
Targets
• No net increase in the mean annual salinity as
measured at Tanamerah and Yalliawirra gauging
stations.
• A reduction in turbidity levels and sediment loads in
the waterways within the catchment.
• Maintain the levels of heavy metals, total nitrogen
and total phosphorus below the target limits set by
Environment Australia for aquatic ecosystems.
• Define the limits of sustainable water use for
groundwater within 5 years.
3.3
Water and Rivers Commission
Natural Resource Management Plan for the Brockman River Catchment
• Use water resources below sustainable limits within
10 years.
• Maintain water regimes in wetlands sufficient for
wetland ecosystems.
• All schools within the catchment involved in the
Ribbons of Blue program.
• All local government town planning schemes to
incorporate water sensitive design principles in 10
years.
• Educate 80% of the people in the catchment about
current best management practice to reduce saline
water, nutrient, sediment and chemical input into the
surface and groundwater in the catchment.
Strategies and actions
3.2.1 Assess and monitor water quality
• identify all sources of pollution by establishing a
sampling program along the Brockman River and
major tributaries then prioritise sources of key
pollutants
• continue to use data from the Water and Rivers
Commission gauging stations (Tanamerah and
Yalliawirra) to monitor changes in the salinity and
quantity of water in the Brockman River
• encourage community involvement in continued
ground and surface water quality monitoring in the
Brockman River catchment to determine changes
• encourage schools to become involved in the Ribbons
of Blue program to monitor water quality.
3.2.2 Decrease the input of nutrients and other
pollutants into the waterways
• encourage the use of soil and tissue testing to
determine the optimum timing, method and rates of
application, and types of fertilizers to be applied to
productive land
• review with landholders the flight path of aircraft
spraying crops or spreading fertiliser to decrease or
eliminate the impacts of spray drift on vegetation and
nutrients entering the waterways
• encourage landholders to prevent direct access of
livestock to watercourses to reduce nutrient input
• manage drains to minimize runoff velocities and
volumes to ensure the control of nutrient and
sediment loads within acceptable limits
• eliminate or reduce polluting activities by asking
landowners who are a source of pollution to clean up.
In the case of serious point-source pollution, if
encouragement doesn’t work, the Local Government
Authority will contact the DEP and request their
assistance
• ensure that weed and pest control programs in the
bushland near watercourses are carried out in a
responsible manner to avoid waterway contamination
• implement pollution control measures to ensure
discharges of effluent such as agricultural chemicals
and intensive agriculture wastewater into receiving
waterways are within acceptable limits
• design contingency plans with the Local Government
Authority, Water and Rivers Commission and State
Emergency Service to handle a major chemical spill
in or near a major waterway.
3.2.3 Improve management of saline water
• encourage revegetation of landscape where possible
to reduce the recharge into the groundwater and
waterways
• publicise and enforce drainage controls for surface
and deep drainage to ensure the volume and salinity
of the water discharged off-site does not adversely
affect neighbouring properties or waterways
• develop and implement current best management
practices for retaining on site and managing saline
water from agricultural/horticultural property
• organise a meeting involving CALM, landholders and
community members to review the artificial
maintenance of water levels in Lake Chittering.
3.2.4 Implement Water Sensitive Design immediately
• ensure that new subdivisions (urban, rural living,
industrial, and intensive agricultural ) are located to
minimise nutrient and pollutant input to the water
cycle and incorporate water sensitive design
• incorporate water-sensitive design into the Town
Planning Schemes
3.4
Water and Rivers Commission
Natural Resource Management Plan for the Brockman River Catchment
• implement appropriate controls and management
measures such as detention basins to strip sediment
and other undesirable components from stormwater to
ensure runoff quality from urban developments is
within acceptable limits
• provide public information and guidelines to
residents, industry associations and commercial users
on water-sensitive design and best practices.
3.2.5 Promote sustainable water use
• regulate through the appropriate authorities, the
abstraction of water from the river, its tributaries and
associated wetlands to ensure equitable distribution
between landholders, community and environmental
requirements
• encourage the community to adopt water
conservation principles throughout the catchment.
How the proposed actions respond to the
following suggestions from the Brockman River
catchment community forum:
• Develop big picture of problem areas (see Swan
Catchment Strategy and this plan).
• Establish list of contact people.
• Identify chemical composition of water to
establish salts (see Actions 3.2.1).
• Urban and industrial development in the townsite
of Bindoon (see Actions 3.2.4).
• Use slotted pipe at base (4 m) trench to catch
leached water and divert for irrigation (see
Actions 3.2.5).
• Divert water from river during floods into storage.
Divert saline water to storage for use in saline
water applications (eg rainbow trout) (see Actions
3.2.3).
• Integration of agency services, such as between
lake and river (see Actions 3.2.3).
• Proper drainage (see Actions 3.2.3).
• Stormwater to be retained on site (see Actions
3.2.4).
3.3 Managing salinity and soil
degradation
Waterlogging and saline seepages are becoming
commonplace throughout the Brockman River
catchment. This increased soil salinity contributes to the
loss of native vegetation and reduces productivity on
agricultural land.
Land clearing, cultivation and livestock grazing causes
increased compaction and loss of soil structure. This
leads to accelerated loss of topsoil through wind and
water erosion. Protection of native vegetation and
revegetation wherever possible is an important
component in preventing erosion and rising
groundwater.
Objective 2
To reduce and prevent salinity and soil degradation;
ensure sustainable land use and increase profitable
production.
Baseline knowledge
• 30 major subcatchments identified in the Shire of
Chittering within the Brockman River catchment, 12
of these subcatchments recorded high or severe soil
salinity, 8 have low or medium soil salinity, and 7
have no soil salinity.
• Further information on salinity and soil degradation is
contained in the following reports.
“Salinity Survey in the Shire of Chittering”. (1997) Ken
Angell. Department of Agriculture WA.
“Degradation in the Brockman River and Ellen Brook
catchments, Western Australia.” (2000) Brian Lloyd.
Department of Agriculture, WA.
Targets
• Halt the rise in groundwater levels in the catchment
within 20 years.
• No net increase in area of soil affected by salinity.
• Reduce the level of in stream salinity within the
subcatchments north of Bindoon.
• Increase the productivity of saline land by 50%.
3.5
Water and Rivers Commission
Natural Resource Management Plan for the Brockman River Catchment
• Identify all areas of potential wind and water erosion
and undertake remedial action on 50% of sites in 10
years.
• All subdivision applications assessed according to
land capability and suitability.
• Establish 50 hectares of perennial pasture in 5 years.
• Educate 50% of the people in the catchment in current
best management practices for irrigated horticulture
and erosion control within 5 years.
Strategies and actions
3.3.1 Assess soil salinity and degradation in the
catchment.
• identify and monitor areas susceptible to soil salinity
and waterlogging within the catchment
• identify and map “hot spots” for soil degradation,
nutrient and sediment export
• identify and map areas within the catchment
susceptible to wind and water erosion.
3.3.2 Improve ground and surface water
management
• use clearing and development controls to protect
native vegetation on large and small parcels of land
• rehabilitate and stabilize eroded areas to control
recharge and increase water use
• encourage landholders to undertake current best
management practices in areas experiencing
waterlogging and soil salinity to lower the
groundwater and rehabilitate degraded lands
• develop and encourage landholders to undertake
current best management practices for irrigated
horticulture, pasture and crops to reduce run off and
recharge to groundwater
• trial and encourage landholders to undertake
alternative farming strategies such as alley farming
and woodlots to reduce recharge to groundwater
• develop and encourage landholders to undertake
appropriate best management practices such as grade
banks for surface water control to manage the
quantity and quality of runoff from paddocks
• construct roaded catchments (sealed with clay) on
recharge areas to divert fresh water into dams for use
in irrigation.
3.3.3 Implement erosion control
• develop and implement current best management
practices such as no till farming in consultation with
landholders and community to address the loss of
topsoil and soil fertility
• encourage landholders to undertake erosion control in
areas experiencing wind and water erosion
• encourage landholders to replace annual pasture
systems with perennial pastures to ensure continuous
soil cover.
3.3.4 Improve land-use planning
• encourage the development of farm management
plans that identify land capability and ensure
sustainability of land uses
• scrutinise subdivision applications to ensure
protection of natural resources in perpetuity
• ensure all re-zoning considers land capability to
guarantee the most appropriate and sustainable use
• locate rural residential and urban areas so they do not
impinge on agricultural land or remove valuable
agricultural soils and microclimates from production.
3.3.5 Encourage further salinity research
• encourage and support further research into saltland
agronomy.
How the proposed actions respond to the
following suggestions from the Brockman River
catchment community forum:
• Identify commercial options for salt tolerant
species in the Brockman River catchment (see
Actions 3.3.5).
• Abstraction of surface water needs to be regulated
by the appropriate authorities WRC ( see Actions
3.2.5).
• Planting of recharge areas (see Action 3.2.3).
•
Farm plans to identify land capability,
sustainability, impact on environment ( see
Actions 3.3.4).
• Compatible development (see Actions 3.3.4).
• Subdivision to be based on landform rather than
square blocks, includes all infrastructure (see
Actions 3.3.4).
3.6
Water and Rivers Commission
Natural Resource Management Plan for the Brockman River Catchment
3.4 Managing waterways and
wetlands
In the early days of settlement from 1843, the Brockman
River was shallower and swampy conditions prevailed
in the valley during the winter months. Progressive
clearing for settlement, deepening of the river, draining
of the floodplain and loss of riparian vegetation has
altered this condition. The increase in water velocity has
changed the course of meander bends and caused
undercutting of the banks. This has led to erosion and
sedimentation problems in the river. Loss of fringing
vegetation has also contributed to increased movement
of topsoil and associated nutrients into the waterways.
In the upper catchment at Wannamal, extensive clearing
in the 1950s and 1960s and a drainage system
constructed in the early twentieth century to drain the
Wannamal Lakes has increased the water flow to the
Brockman River. Water now entering the river system is
becoming progressively saline changing the ecology of
the lakes and wetlands along its length. This has resulted
in the fringing vegetation becoming degraded and salt
sensitive species are being replaced by salt tolerant
species thus changing the nature of the communities
present today. Without the protection of fringing
vegetation, sediment is carried into the waterways and
deposited in the lakes that have now become shallower
and tend to flood outside the reserve boundaries.
Figure 9: Condition rating of the Brockman River
foreshore as a percentage of the full reachof the river.
A Grade: Foreshore vegetation is healthy native bush.
B Grade: Weed invasion, mainly grasses, evident in
foreshore vegetation.
C Grade: Some trees present, understorey weeds and
pasture, some bank erosion.
D Grade: Eroding and/or weed infested ditch.
Objective 3
To restore the natural functions of the river
channels, foreshores, floodplains and wetlands
through protection and rehabilitation.
Baseline knowledge
• A foreshore assessment of the main channel of the
Brockman River was carried out in 2001. Figure 9
shows the percentage of foreshore in each condition
rating using the Pen and Scott method, 1995.
• The environmental condition of the main channel
foreshore is mostly moderate to poor as indicated in
figure 10.
• The fencing status of the main channel of the
Brockman River was carried out in 2001 and is
illustrated in figure 11.
Figure 10: Environmental rating of the Brockman
River foreshore as a percentage of the full reach of the
river.
Figure 11: Fencing Status of the main channel of the
Brockman River as a percentage of the full reach.
Fencing refers to fencing on both sides of the channel
and suitable for excluding livestock.
General Foreshore Condition
50
40
30
20
10
0
Foreshore Length (%)
A
B
C
D
Condition Rating
Environmental Rating of Foreshore
50
40
30
20
10
0
Length of Foreshore (%)
Rating
Excellent
Good
Moderate
Poor
Very Poor
Environmental Rating of Foreshore
100
90
80
70
60
50
40
30
20
10
0
Length of Foreshore (%)
Status
Not Fenced
Fenced
3.7
Water and Rivers Commission
Natural Resource Management Plan for the Brockman River Catchment
Targets
• Complete foreshore assessments of the major
tributaries of the Brockman River in 5 years.
• Fence to exclude livestock and rehabilitate the
riparian vegetation on 50% of the main channel of the
Brockman River and 30% on major tributaries within
10 years.
• Educate 50% of the people in the catchment about
river processes and restoration of riparian habitat.
Strategies and actions
3.4.1 Assess the status of waterways and wetlands
• undertake a review of the foreshore assessment of the
Brockman River, its major tributaries and associated
wetlands to monitor the status of riparian vegetation
• establish and implement a program to measure and
monitor river and wetland health using aquatic fauna.
3.4.2 Improve management of waterways, foreshores
and floodplains
• encourge landholders to fence off and rehabilitate all
defined watercourses
• identify costs and provide economic incentives to
support and encourage landholders to manage, protect
and rehabilitate foreshores and waterways to enhance
their natural functions
• protect river banks, wetlands and foreshores by
permanently excluding livestock
• develop methods of fuel reduction in foreshore areas
to minimise fire risk
• encourage the strategic planting of floodplains using
either native plants or agro forestry woodlots to
restore floodplain function and prevent the main river
channels from creating alternative courses
• encourage the use of perennial pasture species on
floodplains to ensure sustainable summer grazing by
livestock and maximum water uptake
• research and trial native pasture species for use on the
floodplains
• promote sustainable grazing practices on the
floodplains to prevent overgrazing and compaction
• raise landholder and community awareness of river
processes and restoration of the riverine habitat
through field days and workshops
• ensure that infrastructure such as bridges, river
crossings, culverts and fencing across channels
doesn’t interfere with the natural flow of the
waterways and cause local flooding or contribute to
erosion.
3.4.3 Improve the planning process to protect
waterways and wetlands
• develop and implement river restoration plans for the
Brockman River, major tributaries and wetlands to
restore and prevent further damage to the riverbed
and banks and protect assets such as fringing
vegetation, fences and buildings
• negotiate with Local Government Authorities to
ensure adequate setbacks from waterways of new
horticultural enterprises are enforced as conditions of
development
• negotiate with Local Government Authorities to
include fencing of waterways, rehabilitation and
protection of foreshores, and designated building
envelopes to prevent building on floodplains as
conditions for subdivision
• negotiate restrictive covenants between those holding
land tenure and the Water and Rivers Commission to
ensure protection and management of floodplain,
foreshore, riverbanks and channel
• ensure construction of the Perth-Darwin Highway and
others roads cause minimal disturbance to the
environment and that construction in no way affects
the quality of runoff, causes erosion or exacerbates
drainage.
How the proposed actions respond to the
following suggestions from the Brockman River
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