South West Waterways Values, Condition & Impacts A context for water issues in the West RFA
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Transcript of South West Waterways Values, Condition & Impacts A context for water issues in the West RFA
South West South West WaterwaysWaterways
Values, Condition & Values, Condition & ImpactsImpacts
A context for water issues in the A context for water issues in the West RFAWest RFA
South West South West WaterwaysWaterways
Values, Condition & Values, Condition & ImpactsImpacts
A context for water issues in the A context for water issues in the West RFAWest RFA
Dr. Tim Dr. Tim FletcherFletcherDr. Tim Dr. Tim FletcherFletcher
IntroductionIntroduction General presentation - General presentation - sets the context for sets the context for
more specific presentations which followmore specific presentations which follow
The information presented is not “new” The information presented is not “new” — it is a broad summary of the state of it is a broad summary of the state of
knowledge of regional waterwaysknowledge of regional waterways
Presents the big picture of waterways in Presents the big picture of waterways in the region - both the condition & impactsthe region - both the condition & impacts— puts RFA water issues in regional contextputs RFA water issues in regional context
OutlineOutline Waterways in the West RFA regionWaterways in the West RFA region
Values & uses (demands) of Values & uses (demands) of waterwayswaterways
Impacts on waterwaysImpacts on waterways
Condition of regional waterwaysCondition of regional waterways
Methods to protect waterway Methods to protect waterway valuesvalues
Waterways within the Waterways within the West RFAWest RFA
Covers part of 16 river basinsCovers part of 16 river basinsGoulburnGoulburn CampaspeCampaspeLoddonLoddon AvocaAvocaYarraYarra MaribyrnongMaribyrnongWerribeeWerribee Wimmera-AvonWimmera-AvonMooraboolMoorabool BarwonBarwonOtway CoastOtway Coast Lake CorangamiteLake CorangamiteHopkinsHopkins Portland CoastPortland CoastGlenelg Glenelg MillicentMillicent
Waterways in the Waterways in the Corangamite regionCorangamite region
(Barwon, Moorabool, Lake Corangamite & Otway (Barwon, Moorabool, Lake Corangamite & Otway Coast Basins)Coast Basins)
Colac
Geelong
Apollo Bay
Ballarat
Lismore
Forrest
Meredith
Timboon
Port Campbell
Cobden
Simpson
Winchelsea
Anglesea
Anakie
Linton
CamperdownM
oorabool RLake
Corangamite
Barwon RL
eigh RWoady
Yaloak R
Curdies R
Gellibrand R
Aire R
Waterway Values & Waterway Values & UsesUses
EnvironmentalEnvironmental
EconomicEconomic
SocialSocial
Many competing Many competing demands...demands...
Economic & Social Economic & Social ValuesValues
Water supplyWater supply— drinking & domestic (e.g. garden watering), industrial, drinking & domestic (e.g. garden watering), industrial,
agriculture (stock & irrigation)agriculture (stock & irrigation)
ExtractionExtraction— fish, gravel, sand, soil (floodplain)fish, gravel, sand, soil (floodplain)
Tourism & recreationTourism & recreation— walking, sightseeing, fishing, boating, swimmingwalking, sightseeing, fishing, boating, swimming
AestheticsAesthetics— rural landscape, parkland, urban designrural landscape, parkland, urban design
Waste dischargeWaste discharge— sewerage, industry, stormwatersewerage, industry, stormwater
Environmental ValuesEnvironmental Values InstreamInstream
— habitat for fish, macroinvertebrates habitat for fish, macroinvertebrates (“bugs”), macrophytes (“plants”)(“bugs”), macrophytes (“plants”)
Riparian (streamside) zoneRiparian (streamside) zone— habitat corridor, unique landscape element habitat corridor, unique landscape element
(ecotone)(ecotone)
FloodplainFloodplain— intermittent habitat (billabongs), nutrient intermittent habitat (billabongs), nutrient
transfer, sediment depositiontransfer, sediment deposition
Dynamic, variability, diversityDynamic, variability, diversity
Impacts on Impacts on WaterwaysWaterways UrbanisationUrbanisation
AgricultureAgriculture
ForestryForestry Others (e.g. mining)Others (e.g. mining)
Impacts of Urbanisation Impacts of Urbanisation (e.g (e.g
Geelong, Ballarat)Geelong, Ballarat)
HydrologyHydrology— increased impervious area, decreased vegetation cover increased impervious area, decreased vegetation cover
““flashy catchments” - rapid flows over short timeflashy catchments” - rapid flows over short time leads to downstream erosion & scouringleads to downstream erosion & scouring
— river isolated from its floodplainriver isolated from its floodplain— extraction of flows for water supplyextraction of flows for water supply
Water qualityWater quality— increased sediment transportincreased sediment transport— increased nutrients (N, P) - sewerage, fertilisers, etcincreased nutrients (N, P) - sewerage, fertilisers, etc— reduced dissolved oxygen (DO)reduced dissolved oxygen (DO)— pathogens, heavy metals, hydrocarbons, litterpathogens, heavy metals, hydrocarbons, litter
Channel & riparian zoneChannel & riparian zone— gross modificationgross modification— channelisation, clearing of vegetation - channelisation, clearing of vegetation - loss of diversityloss of diversity— barriers to fish passage (weirs, culverts, etc)barriers to fish passage (weirs, culverts, etc)
Impacts of AgricultureImpacts of Agriculture HydrologyHydrology
— Vegetation removal Vegetation removal ((runoff, erosion, runoff, erosion, groundwater, salinity) groundwater, salinity)— Diversion & storage of stream waterDiversion & storage of stream water
impacts on aquatic communities (flora & fauna)impacts on aquatic communities (flora & fauna)— Flood control (levees, etc)Flood control (levees, etc)
river isolated from floodplain, flow concentration, erosionriver isolated from floodplain, flow concentration, erosion
Water QualityWater Quality— sediment & nutrients (fertiliser use, stock access & sediment & nutrients (fertiliser use, stock access &
cropping, soil erosion)cropping, soil erosion)— pathogens (stock access)pathogens (stock access)— potential chemical contamination (herbicide/pesticide)potential chemical contamination (herbicide/pesticide)— changed organic inputs, dissolved oxygen levelschanged organic inputs, dissolved oxygen levels
Impacts of Agriculture Impacts of Agriculture (cont.)(cont.)
Channel & Riparian ZoneChannel & Riparian Zone— vegetation removal (changed shade, temperature, vegetation removal (changed shade, temperature,
etc)etc)
— de-snagging, channel “cleaning” & “straightening”de-snagging, channel “cleaning” & “straightening” loss of habitatloss of habitat
— channel deepening & erosion (from increased runoff)channel deepening & erosion (from increased runoff)
— fish barriers (storages, weirs, poorly designed fish barriers (storages, weirs, poorly designed crossings)crossings)
— reduced physical and biological diversityreduced physical and biological diversity smaller range of habitats (suits less species)smaller range of habitats (suits less species)
Impacts of ForestryImpacts of Forestry HydrologyHydrology
— short and long-term changes to water yieldshort and long-term changes to water yield— presentation by Dr. Rob Vertessypresentation by Dr. Rob Vertessy
Water qualityWater quality— sediment mobilisation & transportsediment mobilisation & transport— presentation by Dr. Jacky Crokepresentation by Dr. Jacky Croke
Channel & riparian zoneChannel & riparian zone— short or long-term changes to vegetation short or long-term changes to vegetation
structurestructure depending on proximity of harvestingdepending on proximity of harvesting
— generally less than urbanisation or agriculturegenerally less than urbanisation or agriculture
Condition of Waterways Condition of Waterways in SW Vicin SW Vic
Two comprehensive assessments Two comprehensive assessments of environmental condition:of environmental condition:
— Mitchell (1990)Mitchell (1990) 96 sites96 sites
— Index of Stream Condition (ISC) Index of Stream Condition (ISC) (1999)(1999) 217 sites217 sites
Condition Assessment - Condition Assessment - ISCISC
HydrologyHydrology— deviation from natural flowsdeviation from natural flows
Physical formPhysical form— bed & bank stabilitybed & bank stability— barriers to fish passagebarriers to fish passage— instream habitat (snags, etc)instream habitat (snags, etc)
Streamside zoneStreamside zone— vegetation cover & condition, weeds, regenerationvegetation cover & condition, weeds, regeneration
Water qualityWater quality— total phosphorus, turbidity, EC, pHtotal phosphorus, turbidity, EC, pH
Aquatic lifeAquatic life— macroinvertebrate population diversitymacroinvertebrate population diversity
Five sub-indicesFive sub-indices Index of Stream Condition Index of Stream Condition
ResultResultss
Excellent Excellent 13%13%
Good Good 25%25%
Moderate Moderate 26%26%
Poor Poor 29%29%
Very Poor Very Poor 7%7%
ExcellentExcellent— Generally in forested Generally in forested
areas:areas: Otways (e.g. Otways (e.g.
Gellibrand, Barham, Gellibrand, Barham, Ford Rivers)Ford Rivers)
Moorabool River (e.g. Moorabool River (e.g. below Lal Lal below Lal Lal Reservoir)Reservoir)
Very PoorVery Poor— Generally in/near urban areas, or Generally in/near urban areas, or
where intensive agriculture is present:where intensive agriculture is present: Naringhil & Kuruc-a-Ruc CksNaringhil & Kuruc-a-Ruc Cks Yarrowee River & Winter Ck (near BallaratYarrowee River & Winter Ck (near Ballarat))
Mitchell, Mitchell, 19901990
ResultsResults(Mitchell (Mitchell
1990)1990)
Moorabool Excellent (%) 0%
Good (%) 11%Moderate (%) 47%
Poor (%) 39%Very Poor (%) 3%
Barwon Excellent (%) 0%
Good (%) 48%Moderate (%) 12%
Poor (%) 28%Very Poor (%) 11%
Corangamite Excellent (%) 0%
Good (%) 0%Moderate (%) 46%
Poor (%) 41%Very Poor (%) 13%
Otway Excellent (%) 35%
Good (%) 18%Moderate (%) 24%
Poor (%) 23%Very Poor (%) 0%
Good (%) 25%Moderate (%) 26%
Poor (%) 30%Very Poor (%)
Mundy Mundy Gully, Gully, LismoreLismore
Winter Winter CreekCreek
YarroweYarroweee
RiverRiver
MoorabMoorabool ool RiverRiver
Ford Ford RiverRiver
GellibraGellibrandRiverndRiver
Moorabool RiverMoorabool River
Aire RiverAire River
How can we best protect How can we best protect our waterways?our waterways?
Considering thatConsidering that
— there are many different there are many different values/uses of land and watervalues/uses of land and water
……..
Protecting waterway Protecting waterway values...values...
Initial assessment of capability/impacts Initial assessment of capability/impacts of the particular useof the particular use
Best practice land useBest practice land use— urbanisationurbanisation— agricultureagriculture— forestryforestry
BUTBUT all of the above depend on all of the above depend on Long-term environmental monitoringLong-term environmental monitoring
— both broad scale/background both broad scale/background && specific specific
Some referencesSome referencesMitchellMitchell (1990). (1990). The environmental condition of Victorian The environmental condition of Victorian
streamsstreams
Ladson & WhiteLadson & White (1999). (1999). An index of stream condition: An index of stream condition: reference manualreference manual
Commissioner for the EnvironmentCommissioner for the Environment (1988). (1988). State of the State of the environment report 1988 - Victoria’s inland watersenvironment report 1988 - Victoria’s inland waters
Corangamite CaLPCorangamite CaLP (1997). (1997). Corangamite Regional Corangamite Regional Catchment StrategyCatchment Strategy
Fletcher & BrenFletcher & Bren (1999). (1999). Cumulative effects analysis; Cumulative effects analysis; grasping the big picture of environmental change grasping the big picture of environmental change in rivers. in rivers. In Proceedings of 2nd Australian Stream Management In Proceedings of 2nd Australian Stream Management ConferenceConference