The journey so far

I started up this blog a year ago (get it?!). No for serious though, I posted my first blog post in October 2015, not having a clear idea. And I chose the topic of climate change impact on water resources on mere interest. I guess my background in Environmental Engineering and water quality related projects had an impact on it, perhaps?

But I personally learned a lot about the topic and the role of modelling through this journey, which fingers crossed I will continue! 

Now let’s briefly look at the direction we took in exploring this topic!

First I tried to illustrate the importance of climate change and rising temperature on hydrological cycle and how everything is interconnected (What's the big deal?). I tried to “show” this fact through the Last Call at the Oasis documentary, which if you have not seen it yet, I really do recommend it. (Don't take it for granted!)

Then I briefly explored the Integrated Water Resource Management approach, pointing out some of its pros and cons ( The rights and wrongs of IWRM). 

After that we got more scientific and explored the modelling science and introduced the different types of models and different resolutions available for modelling the hydrological responses.( Variety is the spice of modelling!, Different resolutions)

Then I tried to provide an example of how different criteria can be used to facilitate an easier decision making when it comes to choosing a particular modelling approach (The art and skill of decision making).

Next we had the big COP21 coverage, because that was huge and couldn’t be ignored. (Confused about COP21 Agreement, Activist à Paris- COP21 Coverage).

After my mixed-emotions about COP21 was settledJ, I looked into a water quality modelling package(Modelling thequality) and a case study in Nepal that applied that model. (Water quality modelling to the rescue!)

Later a case study that attempted to use lumped modelling approach to test the robustness of models for climate transposability (Climatetransposability- case of Canada and Germany), and finally I felt the desire to write about the debate about lumped and distributed models, because I enjoyed it myself and I wanted to share. (The dilemma-the heated debate)

So there it is, I hope that this blog up to now has helped my readers as much as it helped me to learn new things about the importance of water, the effect of climate change, and more importantly for me personally, the role of modelling.

Here is a short clip on this journey ,It was challenging one for me personally but undoubtedly a nice one,

Honeyeh

*All the photos used in the video are referenced in my blog posts

The dilemma- the heated debate

As I briefly mentioned in the previous post, there is an ongoing historical debate going on about lumped models, which are usually conceptual, and physically-based distributed models. I personally enjoyed reading the literature on this issue. It is quite interesting to see how different authors criticize others’ work!

 

So I decided to write a brief post summarising some of the papers I read and hopefully you will get a sense of the situation. 

You can trace the debates back to 1989, when Beven responded to some the claims of physically-based model promoters. 

Some argue that due to the fact that lumped models are not physically- based and do not consider the physical processes that happen in catchments are not a good choice of modelling approach and that they are over-simplified version of the real world system. Furthermore, there is this criticism towards lumped models that they require long hydrological and meteorological data for calibration which may not always be available. (Abbott et al., 1986)

At this point the other party is clenching their teeth! Saying that distributed models themselves are “lumped” at grid scale and they are far from the real world system as they do not consider the spatial heterogeneity of the system. (Beven, 1989)

Some also argue that since these models consider the spatial variability of the catchment response, they are assumed to be a better approach especially when modelling the environmental changes as these changes only occur in some parts of the catchment (Bormann et al., 2009)

And lumped modelling approach supporters say what can be seen in many papers, that spatially explicit models are complex, and difficult to apply and are demanding parametrically and computationally. (Beven, 2012)

My personal view on this issue is that there is no generally right or wrong decision, as models (whatever their type is) in hydrology are simplification of what really happens at catchments. So I don’t think one can generalize a single best approach as the performance of models vary depending on catchment specification and the aim of the modelling itself. As Seiller, Anctil, and Perrin (2012) concluded from their study, the accuracy and predictive ability of models cannot be anticipated for a specific hydrological and catchment condition, thus, intercomparison approach can be used as an appropriate tool to handle this issue.  

Hope you got a brief perspective of the discussions made in the literature. Quite interesting I have to say, scientific soap opera!

So long,