Natural resource management plan for the brockman river



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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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