Dear Lufuno

Development of a decision support system (DSS model), would be an appropriate method. First, you must calibrate your model based on the existing data on normal condition and then you can check the impacts of hydrological events such as sever drought period or flood. You can use WEAP or Vensim for developing your model.

You must also take into consideration that, during the hydrological events many parameters might be changed. For example, the agricultural activities and the policies for cultivation might be different in wet season and dry season in the region that you want to evaluate. Therefore, if you want to develop the model for an extreme hydrological events such as drought you must predict the consumption and other factors as well and not use the same water consumption for the normal period.

Regards

Pirouz

Dear Lufuno

Development of a decision support system (DSS model), would be an appropriate method. First, you must calibrate your model based on the existing data on normal condition and then you can check the impacts of hydrological events such as sever drought period or flood. You can use WEAP or Vensim for developing your model.

You must also take into consideration that, during the hydrological events many parameters might be changed. For example, the agricultural activities and the policies for cultivation might be different in wet season and dry season in the region that you want to evaluate. Therefore, if you want to develop the model for an extreme hydrological events such as drought you must predict the consumption and other factors as well and not use the same water consumption for the normal period.

Regards

Pirouz

Very nice explanation and guidance Dr. Pirouz. Thank you.

thank you so so much... i really appreciate it and this has help me a lot ...

regards

Lufuno

Aditionally to the response alreday given my contribution to this question focuses on impacts of drought events that typify the arid and semi-arid regions. Under natural conditions (i.e. prior to climate change into account) semi-arid regions such a southern Africa are highly variable in climate, characterised by very low precipitation and high temperatures thus leading to drought. The situation is often exacerbated by the onset of climate change which drives heat waves as well as increased frequency and intensity of drought. The percentage of rainfall that flows on surface (i.e. runoff) to fill dams and to infiltrate the ground to replenish the groundwater storage (i.e. recharge) is very low. For instance in South Africa only 8% of rainfall is runoff. Most of the water is lost due to high evaporation rates, particularly with increased temperature. That is how extreme hydrologic events such as drought impact on water availability.

thank you Chris

In addition to the points mentioned by Dr. Pirouz, I would like to add one more dimension, that is water quality changes with respect to drought condition. We have experienced the situation wherein it is not only the water scarcity but also its deteriorated quality makes the situation much worst during droughts. In coastal region because of low flow condition of the streams due to drought condition, the salinity ingression takes place into the river course and as a consequence of this even the coastal groundwater aquifer gets contaminated.  

Thank you so much Prasad

This is big question , in two words the phenomena Either drought or floods.

thanks

Yes, if it is extreme climatic events, then it is drought and floods. Because of this naturally there will shortage of available water during drought or excess of water during floods. In both cases there will be agricultural crop losses; human and animal deaths; water pollution; soil loss; damages to human settlement; health problems; etc.

Dear Lufuno,

The approach and methods to use will very much depend on the characteristics of your study area(s), definitions of extreme hydrological events, changes and water resources, and data availability.

Regarding extreme hydrological events, the method(s) and model(s) to be applied will be quite different depending on whether you look at floods or droughts. Floods are driven by other hydrological mechanisms and have other (smaller) time scales than droughts. Hence appropriate models will also be different. I would suggest to focus on either floods or droughts for the time being and possibly extend the research to other extremes in a later stage.

What kind of changes do you mean? Climatic changes, land use changes, changes in water management? This will also influence the choice of methods and models. It is important to check that the model(s) you are going to use is (are) able to simulate the effects of changes on water availability, not just the water availability for a historic period. For this and other purposes, you need appropriate data of good quality. In general, the data quality and quantity will determine what you can investigate and can probably not investigate in your research.

Regards,

Martijn

Dear Martin

I am looking at both Flood and Drought.

Dear Lufuno,

That will make things more complicated, since you have to balance between an appropriate model for floods and (another) appropriate model for droughts with each its specific requirements. I would recommend to start with a relatively simple model depending on data availability and see whether you can simulate historic events (also the extreme ones).