I have just started a study examining the risks (especially those relating to waterlogging and associated soil salinity) to low-lying (0 - +5m) agricultural (pasture based) land on the Victorian (Australia) coastline from shallow (0 - 3m) groundwater levels associated with sea levels . At this stage I am interested in developing a conceptual model of the associated risk factors and in the GIS mapping of potentially affected land and not in actually undertaking any 'numerical' modelling of groundwater levels. Thus, I am primarily interested in knowing what factors need to be considered in these situations. That said, in finding this out I would however, still be interested in knowing what numerical modelling approaches have been used in these situations in the past.and am interested links to any papers/results/information from similar/related studies or other advice
Thanks in advance for any advice/links given.
You might find attachments interesting. I suppose you have ocean level forecasting as much as we do by NOAA. Low lying water tables mentioned are commonly affected by rainfall, freshwater flooding and sea level changes (tides, storm surge, etc.). There are many factors in addition to this that can influence effects of sea level influence, including dredging of streams that may allow for increase in coastal influence, changes in stored water released from dams, etc. The risk and frequency of impact is substantially elevation related, so good elevation models based on LiDAR or field verifications of elevations are going to be helpful. The hydrologic cycle also enters, for forest areas with more transpiration than agricultural areas, the water tables may be commonly lower during much of the growing season. Streams that are entrenched such as gullies or tidal waters with frequent flushing water to and from the ocean may not be flooded as frequently as braided stream systems where frequent flooding is common. I would like to advise you to partner with a good hydrologist, soil scientist, botanist, geologist and perhaps others. Trying to model and understand a system from just remote sensing data requires a lot of knowledge and experience to apply what you can obtain, part science and art. If you have streams, wells, sea level and rain gauges, that is background information to help you understand what is happening. Early colonists to America made many hydrologic modifications to contain areas from sea level rise, limit sea level rise and release stored waters to keep out high tides or storms. Some of these are quite ingenious in how they had a personal connection to the land and used that to help protect their rice crops. I would encourage you to partner with a few other scientists to augment your remote sensing capabilities with field study and awareness.
Forgot, report may be useful on documented changes in plant types specific to salinity changes in the Santee River Delta due to reduced instream base flows from upstream reservoir. Other biological indicators such as are changes in fish species, as many freshwater species and perhaps aquatic macrointertebrates cannot handle saline or brackish waters.
Thanks for the info William, I will download and have a look at the papers you suggested. As you say, it is a rather complex situation where a lot of different factors come into consideration. Although I am trained as a geologist/hydrogeologist, I will certainly be consulting with others with more experience in this area, as well as with other scientists in related areas to get their opinions on my work, what I am trying to achieve and how best to proceed from here.
Based on existing spatial information, I have been able to map those areas which: a) are low lying (
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