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Describing the stream and catchment
environment at multiple spatial scales
Janet Stein
ANU Fenner School of Environment
and Society
CC Logo
ANU Fenner School of Environment and Society
Introduction• Australian Hydrological Geospatial Fabric ( “Geofabric”)
– Spatial framework for water information
– Delineates network streams and associated catchment
boundaries at a map scale of ~1:250,000
• Geofabric extension - Stream Environment Database
– 13 lookup tables
– 400+ attributes describing the natural and anthropogenic
environment of every Geofabric network stream and its
catchment
• Characterize important drivers of landscape hydrological,
geomorphological and ecological processes that in turn
influence water resource availability and condition and
ultimately control stream ecosystem patterns and
processes
ANU Fenner School of Environment and Society
Presentation Outline
1. Spatial scale of description
– Segments, sub-catchments and
catchments
2. The lookup tables and summary of
attributes
3. Examples of their application
ANU Fenner School of Environment and Society
Spatial scale of description
• Attributes describe the stream and catchment
environment at multiple spatial scales:
– Local - the stream segment +/- its valley
– Sub-catchment – catchment draining directly to the
stream segment
– Catchment - the contributing area upstream or the flow
path downstream
• Spatial units delineated at 9 second grid resolution
– about 250m
ANU Fenner School of Environment and Society
Segment scale•Segments break the stream network at tributary confluences,
waterbodies, distributary points, cliff lines and breaks in the
mapped stream network
•Segment scale attributes summarize the values of all grid
cells that comprise the stream segment (e.g. segment slope)
ANU Fenner School of Environment and Society
Segment and valley scale
Stream segment grid
cells plus cells
classified as a valley
bottom flat using the
multi-resolution
valley bottom
flatness index
(mrVBF) of Gallant
and Dowling (2003)1
1. Gallant and Dowling ( 2003) A multi-
resolution index of valley bottom flatness
for mapping depositional areas, Water
Resources Research 39(12):1347
ANU Fenner School of Environment and Society
Sub-catchment scale
• The grid cells draining
directly to the stream
segment
• Sub-catchment scale
attributes summarize the
values of all grid cells that
comprise the segment sub-
catchment
ANU Fenner School of Environment and Society
Segment
Catchment scale
Summarize (as appropriate):
• all of the grid cells upstream
of the stream segment
outlet (e.g. catchment
average rainfall)
• the grid cells downstream of
the segment outlet (e.g.
average downstream slope)
ANU Fenner School of Environment and Society
Catchment – contains all segment sub-
catchments upstream of the segment outlet
Segment
outlet
The lookup tables
• Derived using best available data sources
with national coverage
• Links to the Geofabric network streams
and catchments via shared unique
segment identifier (field
SEGMENTNO=NCB_ID)
ANU Fenner School of Environment and Society
ClimateParameters describing:
• annual, seasonal and extreme rainfall,
temperature and solar radiation
• climatic constraints on plant growth
• rainfall erosivity
ANU Fenner School of Environment and Society
Stream segment and
valley bottom
average coldest
month minimum
temperature
Catchment average coldest
month minimum temperature
Terrain• Elevation and elevation
derivatives (relief, slope,
aspect)
• Catchment area and
shape
• Network position
(Strahler stream order)
• Indicator of valley
confinement
• Distance from source /
outlet
ANU Fenner School of Environment and Society
Distance from source (catchment length)
Substrate
• Soil hydrological
characteristics
– saturated hydraulic
conductivity, available
water holding capacity,
sand and clay content
• Lithological
composition
– % area underlain by
rocks classified into
broad lithological
groupings,
unconsolidated
material, old rocks
ANU Fenner School of Environment and Society
Catchment proportion unconsolidated materialGeology data source: Geoscience Australia
Catchment water balance
• Monthly time series and
summary statistics of modelled
monthly runoff (1970-2008)
• Single bucket water balance
model - runoff accumulated
downstream along DEM derived
flow pathways
• Also statistics 30 year period
(1971-2000)
• Statistics include annual and
seasonal mean and maximum,
inter- and intra-year variability
ANU Fenner School of Environment and Society
Monthly mean accumulated runoff (GL)
Average monthly maximum
accumulated runoff (GL)
Modelled runoff with observations
from 331 gauges (Peel et al 2001)
Catchment Water Balance Summary Statistics
ANU Fenner School of Environment and Society
Vegetation cover• pre-European and extant
• % area by structural grouping
(forests, woodlands, shrubs,
grasses, bare) and by NVIS major
vegetation sub-groups
ANU Fenner School of Environment and Society
Vegetation data source:
National Vegetation Information System
pre-European
Extant
Tamar River Catchment
Forest Cover
Landuse and population
• % area by landuse
category
– 13 categories
reflecting potential
impact on water
quality and quantity
• average and
maximum
population density
ANU Fenner School of Environment and Society
Hawkesbury River Catchment
Urban Landuse
Landuse data source : BRS
River Disturbance Indices
ANU Fenner School of Environment and Society
River
Disturbance
Index (RDI)
� Indices summarise potential
impact of human activities
� Segments rated according to
the intensity and extent of
human activities:
– instream (dams, weirs,
levees, flow diversions)
and
– catchment (landuse,
point sources, logging,
settlement, infrastructure)
� Indicator of pressure
Additional tables
Connectivity
–Presence of barriers (dams, cliffs, waterfalls) up or
downstream
–Proportion of stream length that is barrier free
Stream network parameters / habitat availability
–Stream density
–Numbers and density of freshwater habitat features
(waterholes, lakes, springs, large streams mapped as a
watercourse area)
NPP (Net Primary Productivity)
–Monthly and annual mean NPP
ANU Fenner School of Environment and Society
Applications• Data supplied to a wide range of government agencies,
university researchers, consultants, NGO’s
• Assisting a variety of tasks e.g.
• Modelling freshwater biodiversity compositional turnover /
species distribution (frogs, river invertebrates, wetland plants,
mussels, fish)
• Survey design - selecting streams satisfying particular criteria
e.g. unregulated, size
• River health / condition assessment e.g. modelling reference
condition for the MDB Sustainable Rivers Audit, updating
Victorian Index of Stream Condition
• Identifying high conservation value aquatic ecosystems
Murrumbidgee River, Northern Australia
• Development of regional frameworks
ANU Fenner School of Environment and Society
Ecohydrological environment
classification
ANU Fenner School of Environment and Society
•Aim: to develop a continental scale
regional classification of Australian
rivers based on ecologically relevant
aspects of their hydrology
•Streams classified on the basis of
their similarity across a range of
landscape attributes believed to be
key drivers of the flow regime
(climate, catchment water balance,
catchment morphology, geology,
soil, vegetation)
30 group classification with
groups coloured according
to their similarity
Pusey, B. J., Kennard, M. J., Stein, J. L., Olden, J. D., Mackay, S. J., Hutchinson, M. F. and Sheldon, F. (2008) (Eds.) Ecohydrological
regionalisation of Australia: a tool for management and science. Innovations Project GRU36, Final Report to Land and Water Australia.
http://lwa.gov.au/products/pn22591
Flow characteristics of ecohydrological environment groups
• 830 gauges
on
unregulated
streams
• 120
ecologically
relevant flow
metrics
ANU Fenner School of Environment and Society
Conclusions
ANU Fenner School of Environment and Society
Stream Environment Database
•Useful extension to the Geofabric
•Data applicable to a wide range of research, monitoring,
assessment and planning tasks at regional to national scale
•setting a context for more detailed and specifically
targeted planning and assessment
•encouraging more co-ordinated management activities
•Consistent and comprehensive national coverage enables
•analysis and assessment of entire drainage basins
regardless of jurisdictional borders
•consideration of all streams large and small
Data availability
ANU Fenner School of Environment and Society
Lookup tables can be downloaded from
Geoscience Australia in ESRI file Geodatabase
format. See:
http://www.ga.gov.au/surfacewater
Acknowledgements
ANU Fenner School of Environment and Society
•The development of the stream attribute tables
was partially funded by the Northern Australia
HCVAE project undertaken for the Department of
Environment, Water, Heritage and the Arts
(Kennard et al 2010).
•Michael Stewardson and Stephen Wealands
assisted with landuse and population density
data
QUESTIONSQUESTIONS
ANU Fenner School of Environment and Society