Land & Natural Environment

Over 94% of the native vegetation in the local government area has been cleared. The remaining 6% exists in pockets and is threatened by isolation, grazing and weed invasion. The main areas of native vegetation remaining are on rocky ridgelines such as the McPherson Range, low lying areas such as black Box depressions and swamps and roadsides.

Less native vegetation usually indicates less native wildlife, as well as increased liklihood of salinity. Records show there are 29 threatened species, including frogs, bats and birds that are likely to occur in the local government area.

Council, Murrumbidgee Irrigation and Landcare Groups have been replanting native vegetation for a number of years within the region in an effort to manage salinity problems, provide a more beautiful environment, and care for our wildlife.

In the city area, planting of natives has been undertaken at recharge sites such as Scenic Hill (usually upslope, where rainfall sinks into the ground) and discharge sites such as Clifton Boulevarde (usually down slope, where groundwater rises to the surface). This program of planting will be continuing into the future.

Useful links:

NSW Department of Environment & Conservation
NSW Department of Planning
NSW Department of Natural Resources
NSW Department of Local Government
Local Government & Shires Association of NSW
Murrumbidgee Irrigation|
Native Vegetation Guide to the Riverina
NPWS Cocoparra National Park Profile
Charles Sturt University - Virtual Herbarium
Flora for Fauna
NSW NPWS Atlas of Wildlife
Queensland Fruit Fly Management Guide

Salinity

What is Salinity?

Salts are a natural part of the landscape in Australia and are found in the rocks, soil and shallow groundwater. Some salt is also carried within rain drops. Changes in land use over time have caused salts normally stored in soils and rocks to be dissolved in water and brought to the surface. When the water evaporates, the salts concentrate at or near the lands surface, and salinity can become a problem. It should be remembered though that whilst salt occurs naturally, the way we use and manage our land and water resources has a large impact on salinity.

Like many urban areas, Griffith and its villages are located in a salty landscape. Over watering of lawns, gardens and sporting fields can cause the groundwater to rise to the surface, bringing with it salts. Leaky pipes (stormwater, town water supply and sewage) and swimming pools can also cause water table levels to rise. Urban salinity can also be related to sub-surface water flows being impeded by structures such as roads and by poor drainage conditions. There may also be some influence to the mobility of salt and watertable depth locally, due to the use of water in the surrounding irrigation area.

Salinity damage shortens the life of urban infrastructure such as roads, buildings, paving, water and sewage pipes and can have detrimental effects on vegetation such as trees, gardens, lawns and playing fields. This leads to costly maintenance and repair by homeowners and councils.

To manage urban salinity the problem normally needs to be addressed at both the catchment (the surrounding rural and urban landscape) and local levels. This is because the groundwater responds to both catchment and local factors. Management practices within an urban centre alone are not normally sufficient.

At the local level, in the urban centre itself, there a number of management strategies that councils and residents could implement. These include:

• Avoiding over-watering public parks, sports fields, home gardens and lawns
• Planting large native trees and shrubs in open spaces
• Investigating the extent of leaking channels and pipes and implementing a pipe replacement program using corrosion resistant materials
• Assessing the likelihood that current and proposed water storages, artificial lakes and drainage basins contribute to groundwater recharge, with strategies to minimise where possible
• Ensuring that water drains away from infrastructure developments to avoid ponding
• Connecting septic tanks to piped sewerage systems where possible
• Connecting roof drainage to stormwater systems, rather than sullage pits
• Monitoring changes to watertable levels and groundwater quality by installing piezometer ('monitoring bore') networks
• Encouraging residents to establish gardens with low water requirements.
• New houses, buildings or infrastructure in current or potentially salt-affected areas should be built to withstand the effects of salinity. Corrosion resistant materials should be widely used. Durable water-resistant membranes (eg. damp courses in houses) may often be appropriate.

For further information on Urban Salinity, click here to dowload Griffith City Council's Urban Salinity Pamphlet.

Hypoxic Blackwater

The Department of Planning, Industry and Environment (DPIE) have informed Local Government Areas (LGA’s) of possible Hypoxic Blackwater Events throughout the Riverina and Murrumbidgee Catchment area due to wetter than normal conditions.

• Following three hot, dry years, floodplains across the Basin have high leaf litter and grass loads and have not been flushed since 2016.
• Forecasts for the Southern Basin show we are currently in a La Niña cycle. There is potential for high rainfall and flooding in late 2020 to early 2021, similar to late 2016.
• River managers, scientists and environmental water holders are monitoring rivers for potential hypoxic Blackwater and working to reduce impacts of a hypoxic Blackwater event where they can.

What is Hypoxic Blackwater?

‘Blackwater’ is a term used when high levels of organic material and tannins in a river discolour the water making it appear black. The water can then become hypoxic (low oxygen) when the material decomposes reducing the oxygen in the water. Blackwater events occur during flooding when organic material is washed off the river bank and floodplain and into the river system.

Most hypoxic Blackwater events happen after prolonged dry periods such is happening now, when temperatures are warm and there has been an extensive build-up of organic material, such as leaf litter.

Some native fish and crustacea are especially vulnerable to oxygen deprivation. Fish are sometimes able to escape the most badly affected areas by swimming upstream or downstream. The chemicals released from organic material can also make water bodies more alkaline or acidic, potentially resulting in toxic effects on some aquatic organisms.

Is there a risk to humans?

Risks to human health are low if direct contact with hypoxic Blackwater is avoided. Thorough cleansing is advised after any contact with affected water and discoloured or dead fish should not be eaten because of possible health risks.

Will Blackwater have an effect on Lake Wyangan?

At this stage it is highly unlikely that Lake Wyangan will be effected by Blackwater as this type of event occurs mainly in rivers and/or lakes that are fed directly by rivers.

Further information

The Department of Environment and Energy has information on hypoxic blackwater events and water quality.

The Murray–Darling Basin Authority has prepared a water management 101 fact sheet on blackwater and a map of threats to water quality in the Murray–Darling Basin. A short video on blackwater is also available.

Real-time water data by WaterNSW includes DO values for some river gauges in NSW.