A short course in estuarine ecohydrology modelling

Prof. Wolanski (James Cook University and Australian Institute of Marine Science


Lecture #1: An introduction to box modeling in estuarine ecohydrology (2 lessons of 1 hour each)

Box models are used by estuarine ecosystem modellers who simplify the ecosystem by amalgamating species at the same trophic level or habitats in order to assess the throughflows of material or energy in the ecosystem. Two model types will be explained:
1. models based on conservation of mass between various trophic levels: several examples are given. The lesson will focus mainly on

  • the Guadiana Estuary in Portugal, where the estuary is impacted by flow regulation at the Alqueva dam. An estuarine ecosystem model is used to assess the effectiveness of various flow regulation regimes in recovering or maintaining the health of the estuary.
  • coastal coral reefs affected by land-use in nearby watersheds.

2. models based on transfers of energy between eco-zones.  The lesson will focus on the use of this model to quantify the health of the urban marine environments in Tokyo, Shanghai, Pearl Harbor, the Pearl Estuary, Hong Kong, Manilla, Bangkok, Ho Chi Minh City, Klang, Singapore, Jakarta, and Darwin. Not one of these harbours was developed in an ecologically sustainable way, with environmental impacts ranging from degradation to ecosystem collapse.  In some cases development continues to occur at the cost of environmental degradation; in others rehabilitation of the marine ecosystem is vigorously addressed following increased wealth, though the ecosystems remain severely depleted. The key mechanisms preventing ecosystem recovery in wealthy countries’ harbours appear to be habitat loss, habitat degradation and habitat modification. Currently there is no successful world’s best practice for environmental management of harbours, as these 12 case studies demonstrate. Box models can be used to evaluate which ecosystems could be recovered by realistic remediation measures and which one cannot be recovered.

Lecture #2: The LOICZ biochemical model for turbid estuaries (2 lessons of 1 hour)

  • Lesson 1: The LOICZ model:

The LOICZ biochemical model is a useful tool to understand where the nutrients go when reaching an estuary, are they flushed to sea or are they causing eutrophication of the estuary or coastal waters. The model is simple to use, yet realistic, and has been used widely worldwide. To use the model, some field data are needed on the inflows and outflows of water and nutrients from the estuary. Such data are relatively easy and inexpensive to obtain.  The model has problems however in turbid estuaries, i.e. where the suspended fine sediment (mud) concentration (SSC) is high. The problem is not with the reduction of light available for photosynthesis, since this is already incorporated in the model by assimilating field data on the status of nutrients and chlorophyll-a, instead the problem is due to the fine sediment absorbing dissolved nutrients in particulate forms in the turbidity maximum zone of tidal estuaries (thus behaving like a sponge inhibiting eutrophication) or desorbing nutrients in quasi tideless coastal lagoons (thus facilitating eutrophication). The new LOICZ model for turbid estuaries, produced by Eric Wolanski and Dennis Swaney, incorporates this process through a partitioning coefficient Kd, which can also be readily calculated from a few additional field data. The model has been applied to four turbid Indian estuaries. The results will be discussed.  The student will be provided the software in Excel. The student must have a PC which runs Excel. 

  • Lesson 2: After lesson 1, the student is asked to, outside class time, find suitable data for an estuary and apply the model. Students can work in groups of 2 on one estuary each. During a one-hour class, the students will present their results in the class. The preparation time per student is probably about 2-4 hours. 

Lecture #3: The UNESCO-ROSTE Estuarine Ecohydrology model. (2 hours)

The student will be introduced to this model and will learn to use it.
The student will need a PC using Windows XP as the operating system; the software will be provided. The model will be a black box if the student does not have FORTRAN on his/her PC; otherwise the student will have access to the program and can then see for him/herself how the model works.

Lecture # 4: An assignment (5-10 hours preparation by the student + a public presentation + an open discussion)

The student will prepare an essay on an estuary or coastal water – the student must have field data –real or inferred for nearby or similar sites - of his/her own on the estuary bathymetry, freshwater runoff, tides, nutrients in the river, the estuary, and coastal waters and eventually benthic/coastal wetlands  properties.
In this essay the student will apply to his/her field site
-the LOICZ model
-the UNESCO-ROSTE model
and write an essay.
In this 5-10 pages essay the student will

  1. explain how the models were applied
  2. clearly explain the results using a scientific interpretation.
  3. place his/her results within the context of the scientific literature.

The student will present his/her results to the class (15 min per student).
An open discussion will be organized with all students participating.

Recommended reading:
Wolanski, E. (2007). Estuarine Ecohydrology. Elsevier, Amsterdam, 157 pp.

Information about the lecturer.

Professor Eric Wolanski is a coastal oceanographer and environmental engineer. His research interests start from the oceanography and sediment dynamics of coral reefs, mangroves, and muddy estuaries. They also include the interaction between physical and biological processes determining the ecosystem health in tropical riverine, estuarine and waters. Eric is leading the UNESCO-ROSTE estuarine ecohydrology modelling effort to quantify the impact from farming, dams, irrigation and urbanisation on the ecological services that estuaries provide to humanity. The ecohydrology models that have resulted have been applied to assess the human impact on coral cover in the Great Barrier Reef, Darwin Harbour, coastal waters of Micronesia, and savannah ecosystems. Eric has more than 300 scientific papers and seven books. He is a fellow of the Australian Academy of Technological Sciences and Engineering, the Institution of Engineers Australia, and l'Académie Royale des Sciences d'Outre-Mer. He was awarded an Australian Centenary medal for services in estuarine and coastal oceanography, a Doctorate Honoris Causa from the Catholic University of Louvain, and a Queensland Information Technology and Telecommunication award for excellence. Eric is the chief editor of Estuarine, Coastal and Shelf Science, Wetlands Ecology and Management, and the Treatise of Estuarine and Coastal Science. He is a member of the editorial board of Journal of Coastal Research, Journal of Marine Systems, and Continental Shelf Research. He is a member of the Scientific and Policy Committee of IGBP’s LOICZ (Land Ocean Interactions in the Coastal Zone) and of EMECS (Japan's-based International Center for Environmental Management of Enclosed Coastal Seas).