WATER
Australia's fragile environment combined with past management practices
means that the natural resources (soil, water and vegetation) of many
areas are degraded. Natural resource degradation affects our environment
and the quality and quantity of natural resources available to current
and future generations.
People form landcare groups to work together to improve the management
of natural resources and to care for their local environment.
Landcare groups throughout NSW are working on a wide range of water
related issues. These include:
· Estuarine and floodplain degradation
· Salinity (irrigation, dryland, urban)
· Riparian (river corridor) degradation
· Water quality
· Water sharing and management
· Wetlands
Estuarine and Floodplain Degradation
The issue
Floodplain degradation is the erosion of land forming the alluvial
river flats that are periodically covered by floodwater. These areas
are often the most productive lands in a catchment. Degradation includes
the loss of river flats by topsoil stripping or gullying, loss of property,
crops, livestock and wildlife habitats, including estuaries.
Floodplain degradation can be caused by inappropriate development of
the floodplain and the clearing of vegetation. Floodplain erosion often
occurs where there has been a change in land use from grazing to cropping.
Erosion is increased by artificial drainage works and other structures
which concentrate flood flows.
What can be done?
There are several options for good floodplain management including:
· ensuring artificial systems follow natural drainage patterns
· keeping enough pondage on floodplains to slow flood waves moving
downstream
· constructing wide floodways to avoid water travelling at high
speed
· maintaining native vegetation in broader natural floodplain
areas.
For further information about Estuaries please click here.
(Information courtesy of the Department of Environment and Climate
Change)
For further information about Floodplain Management please click
here.
(Information courtesy of the Department of Environment and Climate Change)
Salinity
Salinity results from groundwater rising to the surface of the land
and bringing with it salts that naturally occur in these water systems.
Native trees and plants with their deep roots were once effective at
using most of the water entering the soil from rainfall, thereby preventing
groundwater from rising.
Large amounts of native trees and plants have been cleared and replaced
with annual crops and pastures, irrigated agriculture and town gardens
and lawns that have shallower roots and different growth patterns. This
has allowed more rainfall to leak into groundwater, causing the watertable
to rise and bring salts to the surface.
Salts accumulating near the surface cause widespread land, water and
environmental degradation. Salinity can kill or stunt trees, crops and
pastures in rural areas, and damage buildings and other structures in
urban areas.
As water is diverted for irrigation, urban and industrial water supplies,
there is less flow to dilute the salt washing into rivers and streams.
Increased salinity levels in rivers limits the usefulness of water supplies
to towns, irrigation developments and aquatic ecosystems.
Irrigation salinity and waterlogging
The issue
In many irrigation areas, salinity problems have been increased by
the large amount of water which is applied to crops and pastures.
Waterlogging is a separate but related problem that occurs when soil
is saturated with water for longer than one day. Waterlogging contributes
to rising watertables. Shallow watertable areas are more prone to waterlogging.
Salinity and associated waterlogging problems are increasing in NSW
irrigation areas, particularly in the Murray and Riverina.
What can be done?
Improved soil, crop and water management combined with revegetation
on strategic sites can help prevent salinity problems and reclaim affected
land.
The amount and duration of water lying on the ground needs to be minimised
to prevent the development and spread of shallow watertables. This can
be done through better surface and sub-surface drainage, improved irrigation
systems, groundwater pumping, reuse of water and changes to the timing
of irrigation.
The planting of trees and use of salt-tolerant plants helps to manage
existing shallow watertable areas. Resting land from intensive irrigated
production can help to slow and prevent salinity problems.
Dryland salinity
The issue
Dryland salinity occurs when groundwater, and the salts it contains,
rise to the soil surface. It is mainly due to the clearing of deep-rooted
native vegetation for rain-fed crop and pasture production.
Dryland salinity causes vegetation loss and the formation of bare areas
that are susceptible to erosion. It occurs predominantly on the tablelands
and western slopes of NSW and is associated with less productive land.
What can be done?
The development of dryland salinity can be slowed by retaining native
vegetation, revegetating recharge areas in the upper parts of catchments,
and replacing annual shallow-rooted crops and pastures with perennial
deep-rooted pastures.
There are several ways to help repair land affected by dryland salinity,
including:
· fencing off affected areas and reducing stocking rates
· using salt-tolerant grasses, herbs, shrubs and trees to revegetate
affected areas
· surface mulching, surface tillage or deep ripping to assist
plant germination
· subsurface drainage
· changing land and water management to reduce the amount of
water seeping into the watertable.
Urban salinity
The issue
Urban salinity is caused by rising watertables. The replacement of
deep-rooted native trees and plants with lawns and gardens has allowed
more rainfall to leak into groundwater, causing the watertable to rise
and bring salts to the surface.
Salinity in urban areas results in bare patches of soil, unhealthy
or dead plants, corrosion of structures and waterlogged ground. It affects
the quality of drinking water, causes roads, bridges, buildings and
house foundations to crumble, corrodes plumbing and can have a serious
impact on native plants and animals.
Urban salinity occurs to some degree in most towns on the western slopes
of the Great Dividing Range.
What can be done?
Prevention and treatment of urban salinity includes:
· growing mainly native plants which require less water
· minimising vegetation clearing
· revegetating key areas
· identifying areas susceptible to rising watertables.
For further information on all forms of salinity please click here.
(Information courtesy of the NSW Government)
Riparian (River Corridor) Degradation
The issue
The riparian zone includes bodies of water and any land which adjoins
or directly influences them. Small creeks, rivers, lakes and wetlands,
the land alongside and surrounding them, including riverbanks, are all
within the riparian zone.
Riverbanks stabilise the shape and slope of rivers. They also provide
habitats for native plants and animals and shelter for stock. They have
become degraded from the natural meandering of rivers, channel blockage,
clearing of vegetation, grazing and inappropriate use of power boats.
Rivers have become degraded from the erosion of their banks and from
sediments, pollution, salinity and structures such as dams and weirs
which modify flows. These factors impact on aquatic plants and fish,
and the quality of water.
In many areas, river beds are lowering due to less sediment or increases
in bed slope, velocity of flows and runoff. This commonly occurs in
rivers where sand and gravel has been extracted or downstream of dams,
weirs or urban areas. River bed degradation can undermine riverbanks,
widen channels, damage structures, cause downstream siltation or flooding,
lower water levels and affect aquatic plants and animals.
What can be done?
Government agencies, local government, community groups and land owners
and users are addressing riparian degradation through:
· river management works, such as bank armouring
· revegetation of riverbanks using trees, shrubs and grasses
· techniques to reduce river velocity
· deflecting river flows
· allocating water to in-river use
· controlling activities, such as gravel extraction, that cause
river bed degradation.
For further information on water resource issues please click here.
(Information courtesy of the Department of Environment and Climate
Change)
Water Quality
The issue
Surface water and groundwater can become contaminated through discharge
or leaching from manufacturing industries, mining, agricultural and
pastoral activities, sewage and landfills. When nutrients are washed
into dams and low-flow waterways from soil erosion or the inappropriate
use of fertilisers, outbreaks of blue-green algae can occur. Urban development
affects water quality through sedimentation and chemical contamination.
In some areas, land clearing and irrigation practices have caused watertables
to rise and bring salts to the surface. These are then washed into waterways
causing salinisation of the water. Acidification of water can result
from the drainage of wetlands in areas of acid sulfate soils.
The diversion of water for irrigation, urban and industrial water supplies
means there is reduced flow in rivers, streams and groundwater systems.
This can have serious impacts on water quality.
What can be done?
Measures which can be taken to protect water quality and prevent contamination
include:
· research into techniques to control pollution and the effects
of pollution on the environment
· reducing the amount of nutrients entering water systems
· repairing riparian land to help filter pollution
· preventing soil erosion so that sediment does not run off into
waterways
· improving sharing arrangements so that water is allocated to
the environment
· improving land and water management practices.
For further information on how the Department of Environment and
Climate Change is dealing with water quality issues please click here
and also
here.
Water Sharing and Management
The issue
Water is one of our most precious natural resources. It needs to be
shared equitably between competing users such as towns, industry and
agriculture, while ensuring that the health of our aquatic ecosystems
is maintained and not compromised.
NSW is at the limit of its available water resources. There is clear
evidence of degradation in our rivers - loss of wetlands, blue-green
algal blooms, carp infestation, decline in native fish populations,
increased salinity and high bacterial levels.
In many areas, the diversion of water for irrigation, urban and industrial
water supplies has altered the natural flow in rivers, streams and wetlands,
affecting the environment.
What can be done?
The way in which water is managed needs to be continuously improved
by adopting more innovative, cost-effective and community focused approaches.
We also need mechanisms to equitably and fairly share surface water
and groundwater between the various extractive users, including agriculture,
mining, industry and towns.
It is important to identify the stresses on our river systems and respond
to these so that further environmental degradation does not occur.
Sound planning is needed to balance retention of water for the environment
and diversion of water for essential uses. In NSW there are more than
30 water management committees developing a water management plan for
their surface water or groundwater system.
For further information on water resource issues please click here.
(Information courtesy of the Department of Environment and Climate
Change)
Wetlands
The issue
Wetlands are important ecosystems. They provide a valuable link between
surface water and groundwater, they filter out nutrients and pollutants
and hold large amounts of water, preventing flooding. Wetlands are also
home to numerous plants and animals, acting as nursery, feeding and
shelter areas for fish and other aquatic life.
Wetlands have been lost through drainage, dredging and filling in for
agriculture or residential land. They are affected by river works, irrigation
and water supply structures, inappropriate management, pollution from
industrial, agricultural and urban runoff, and salinity. In some wetlands,
native plants and animals are threatened by overgrazing and competition
with introduced species.
Drainage of some coastal wetlands has exposed acid sulfate soils that
impact on agricultural and fisheries activities.
What can be done?
Measures which can be taken to protect existing wetlands and improve
degraded wetlands include:
· promoting the importance of wetlands in maintaining property
and catchment productivity
· creating parks and reserves to protect wetlands
· preventing pollution from entering wetlands
· maintaining and improving native vegetation in and around wetlands
· fencing off wetlands from stock and keeping wetlands on farms
as wildlife refuges
· maintaining the natural cycle of flooding and drying out in
wetlands.
For further information on wetlands please click here.
(Information courtesy of the Department of Environment and Climate
Change)
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