Environmental Fluid Dynamics:
Understanding mixing in a turbulent stratified shear flow: Currently work is progressing on understanding mixing in a stratified shear flow using the new PFP with profiling in Blackwall Reach in the Swan estuary. This is an ideal site as the stratification varies seasonally and shear varies between spring and neap tides. All field software, needed to compute the terms in the TKE equations, has been written and we are now in a position to profile a transect along the Thalweg of the estuary with the PFP and derive both the vertical buoyancy flux and the Reynolds stresses from direct measurements and from inverse techniques. Previous comparison between ELCOM and field data in the water column and WRF and meteorological data profiles showed that neither the closure scheme in ELCOM and WRF do a good job for stable conditions. Fieldwork with the PFP, over the next year or so, will be used to develop better closure schemes for ELCOM and WRF.
Understanding vertical mixing in deep lakes: We have known for some time, that the mixing algorithms in both DYRSEM and ELCOM over predict the vertical mixing when applied to very deep lakes, such as Lake Iseo. This is an important failure as all the sub alpine lakes are under threat from global warming and land use change impacts. We propose to use field work with the PFP to separate the mixing processes supported by the benthic boundary layer and associated upslope flux and those induced by direct shear mixing. Likely candidates for field sites are Lake St Clair in Tasmania and Lake Iseo in Italy. The results will then also be applied to the Gulf of Mexico, the bathymetry of which makes it a 4,000m deep large lake. An accurate understanding of deep mixing is essential for the understanding of the persistence of the huge volume of deep low oxygen water and the fate of the organic load from the Mississippi River.
Flux paths in tropical polymictic lakes: Lakes at low latitudes stratify only weakly and so even modest wind events mix the water column to depth. During heating and cooling phases, differential heating and cooling sets up horizontal convection cells. The combination of intermittent vertical mixing and horizontal gravitational convection provides a special environment for algae growth. Little is known about this environment. Field work with the PFP is the 14 reservoirs in Singapore will be used to she light on the underlying processes. The results from these rather small reservoir will then be compared with results from Lake Argyle, a large lake with very active differential deepening/cooling and vertical mixing.
Differential deepening in large system: It is now over 30 years that we proposed the importance of differential deepening as a mechanism for surface layer deepening. Incidental evidence has supported this initial ascertain, but still needed is clarification in large systems. The passage of a hurricane over the Gulf of Mexico offers such an opportunity. Consequently, CWR is working jointly with the Gulf of Mexico Research Initiative and is setting up ELCOM-CAEDYM for the Gulf to run in RMSO. Collaborative work will allow these simulations to be validated, during and after the passage of a hurricane.
Role of non linear internal waves: The work in Lake Constance and Lake Iseo has shown that in deep lakes with shallow surface layers a considerable fraction of the rate of wind working at the surface of the lake is transferred to high frequency solitary type waves via non linear steepening of basin scale internal waves. Work is continuing in Lake Iseo to find a universal parameterization of this energy pathway.
Lagrangian fluid particle motions in environmental flows: Horizontal dispersion in standing waters is supported by vertical and horizontal shear dispersion and kinematic chaos. The latter makes the prediction of path of algal patches very challenging as the mathematical problem is “ill posed”. The aim of this research is to use the CLD to quantify the contribution from chaos for different environmental conditions.
Flow in shallow system: The recent work in Rio de la Plata has shown the importance the Hele Shaw analogy in shallow flow environments. The objective here is develop an understanding of how to separate the depth averaged flow characteristics form the horizontal dispersion.
Fluid Environment Defining the Aquatic Habitat:
Role the habitat plays in algae succession: Recent results from work with the PFP and the new PCA methodology in the Swan estuary, Cockburn Sound and Rio de la Plata have confirmed that algae succession may be unambiguously predicted from a knowledge of the chronology of nutrient availability, light, temperature, salinity, horizontal and vertical dispersion and turbulent rate of strain. We have started to deign and construct and under water microscope, to be attached to the PFP and associated image recognition software that will allow us to obtain profiles with 20cm vertical resolution of phytoplankton and zooplankton species. The PFP will also have 12 sample bottle, triggered from a knowledge of habitat and fluoroprobe output. Combined this will give us, for the first time all the physical habitat state, including the strain rate, nutrient concentrations from the water samples, algal species and algal predation by zooplankton. This should allow us to make considerable progress towards improving CAEDYM so that algal blooms succession can be predicted with certainly. This research will be done in collaboration with the Kinneret Limnological Laboratory (KLL) with field work in Lake Kinneret.
Role of macrophytes in differential cooling: Work in the last year in Lake Argyle has indicated that macrophyte beds around the perimeter of a lake, even as large as Lake Argyle, induced due to shading, very active differential cooling that can lead to underflows over 10’s of kilometres. The objective of this work is to quantify the net exchange between the littoral and pelagic zones of lakes and also understand whether this exchange is being used by the macrophytes in a beneficial way to bring nutrients to the perimeter and remove waste products to depth. This work will be done Lake Monger (1 sqkm) and Lake Argyle (1,000 sqkm).
Model Development:
Three dimensional reservoir simulation model DYRESM-3D: We are actively working on coupling DYRESM with the new Modal Model and construct a pseudo 3D Lagrangian hydrodynamic model suitable for long time climate change simulations; the run times will be similar to DYRESM-1D. Distinct from the DYRESM-1D, DYRESM-3D will have the correct flux path parameterizations making it a suitable driver for CAEDYM. This model will also have the new ice modules. Its first application will be to Lake Iseo, Italy to assess its sensitivity to global warming and increased nutrient loading.
Hydrologic cycle modelling: Currently CWR has three hydrodynamic drivers, DYRESM-1D, DYRIM and ELCOM and one ecological model CAEDYM. We expect DYRESM-3D to replace DYRESM-1D. Over the last year we have also incorporated the open source meteorological boundary layer model WRF into ARMS and the results so far have been little short of spectacular. A number of the configurations in RMSO are using the output from WRF to force ELCOM with greatly improved results over those using a single data series. The objective now is to add surface water and groundwater models to close the hydrologic cycle, all running under ARMS/RMSO, from simulating rain and evapotranspiration to groundwater infiltration, to surface runoff to finally the change sin the running and standing water bodies. The first application of this new technology will be to the complete water system supply Singapore with bulk water.
Applied Engineering Research:
Optimising coastal effluent disposal: Work on two of Perth’s major waste water coastal effluent disposal sites has allowed much better quantification of the relative importance of the effluent nutrient loadings opening up the possibility that ELCOM-CAEDYM can be used as a real time control of the effluent disposal in order to enrich the coastal margin in a controlled fashion similar to terrestrial agricultural practices. The plan is to add all effluent disposals to the RMSO “Perth Coastal” domain and then use field work with the Djinnang IV and the PFP equipped with the new microscope and water samplers to obtain an holistic understanding of nutrient cycling in a coastal margin.
Optimum control of bulk water supply: Over the last 20 years CWR has been intimately involved in collaborative work with Sydney Catchment Authority (SCA) and Melbourne Water (MW); the management of approximately 70% of Australia’s bulk water is assisted by CWR technologies. The objective is to push this work to where all treatment plants, waste and bulk, are incorporated and optimization algorithms are added in order to provide a complete decision support system for water authorities. Collaboration with SCA, MW and the Public Utility Board of Singapore will provide evaluation platforms.
Optimizing reservoir performance for bulk water, flood control, hydropower, carbon sequestration, fish production and recreation value: The objective here is to use the 40 years of research at CWR on lakes to provide decision support to allow a shift of the operation of reservoirs from single objective such as bulk water, flood control or hydropower to an optimum mix that includes carbon sequestration, fish production and recreational or tourist use yielding a much higher economic return for the infrastructure expenditure. Lake Argyle will be used as a test bed. Close collaboration with fish biologists and tourist operators will allow these aspects to be factored into the real-time simulations, thus providing a real-time decision support. Currently we are looking at the pathways for carbon sequestration to the sediments and the incorporation of these into CAEDYM as well as the upgrade of the fish algorithms that are currently in CAEDYM. This work is being done in collaboration with Lake Argyle Tourist operators, the Aquaculture Council of Western Australian, the Western Australian Fish Foundation, The Western Australian Water Corporation and the recreational fishing interests.
Environment and Sustainability:
Benchmarking social well being: Australia has seen a huge spectrum of political leadership over the last 100 years. The objective is to set up the Index of Sustainable Functionality (ISF) for Australia to measure the changes of social well being over this period and ascertain whether governments influence social well being or are changes in technology determining social well being?
Assessing the suitability of using the GDP as a measure of social well being: Is their an optimum GDP: The objective is to compare the ISF with the GPD and see whether there is any correlation.
Influence of wealth inequity on environmental well being: Technology seems to be feeding increasing wealth inequity in most developed countries. What is the impact of this increasing wealth inequity on social and environmental well being?
Impact of globalisation on social cohesion: Technology is leading to ever increasing globalisation. Can we use the ISF to understand the social implications of globalisation?
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