Welcome to the second lesson of this week, and in this lesson we are going to explore a case study. We are going to form the grammar, the taxonomy of indicators and we are going to do the estimations. So today we are going to present the case of Mauritius Island. The case of Mauritius Island is very interesting in terms of the connection between agricultural production and water use. In this session, we are going to see how to form the grammar and how to choose the typologies of water that are going to be relevant, taking into account the characteristics of this case study. Before we start, let me just go back a little bit on the key things that we saw in the previous sessions. First of all, we saw that in MuSIASEM we focus in the importance of water flows for the maintenance of structures in the social ecosystem, so either in societies or ecosystem. We used two different scales and one of them is Anadorol scale, which is called the watershed, the other scale is called a problemshed. In the watershed we use water to delineate the analytical system, and in the problemshed we use societal structures to delineate our analytical system. We also talk about how we are going to use different indicators in each of the levels of the analysis, and how we can choose between intensive and extensive versions of those indicators. We also saw at the very beginning that water is very much connected to other resources and integrated water resource management. And in this case today we are really going to see how it is connected to land and agricultural production. If you remember from previous sessions, we have a taxonomy of indicators which are given by two things. First thing is the indicators of water use, or extraction, recharge, and supply. Those depend on the level of their analysis. And the other part of the indicators is given by the dimension of water that is relevant for our study at each of the levels. So we can define the supply of water from precipitation, from external inflow, but we might as well estimate the direct use of water from a distributed system that is going to produce economic value. Now, let's think about what analytical levels we are going to need. Mauritius is an island, so we are not analyzing the whole archipelago. We are actually just focusing in Mauritius island. Mauritius island is very well known for its sugarcane production, but 90% of that sugarcane production is exported. You're going to see a little bit more about the case study in week six, but I think that's the things that we need to know for now. So how are we going to delineate our analytical levels. We we're going to have Mauritius on the one hand, a society of Mauritius, and on the other hand we are going to have the island, the actual land of Mauritius. So the society in Mauritius is going to be our focal level, and then we're going to dis-aggregate that society in social functions and social sub-functions. On the upper part of this scale and the upper levels of the scale we can see the international market which is clearly very much affecting the social activities in Mauritius. Now the other scales, the natural scales, that we are going to take into account are the ecosystems and the water cycle. In this case we are going to analyze the use of water by the social functions, like agriculture, and social sub-functions which are going to be the different crops. At the ecosystem level in the watershed perspective, we are going to analyze the supply of water from the ecosystem to the water bodies, that's how much recharge the water bodies are having. We are going to do this for the whole island, but we are going to see how at a certain point in the feasibility assessment, in the comparison with the ecosystem boundaries, the ecosystem constrains, we are going to change our analysis, our structure, from social functions to water catchments. That means that we're going to be able to move the analysis for water catchments and agriculture for water catchments for the whole economy depending on the needs we have for our analysis. Now, if you look at the table of the nexus elements for Mauritius 2010 and you focus on water, in this table, you can always put any of the indicators that you have estimated. In this case, we chose to use water extraction because it was more related to gross energy requirement in energy. Now let's keep this in mind, and in the next sessions we're going to see how we arrive to these numbers. In conclusion, in Mauritius most of the sugarcane is exported and that goes to produce biofuels. Also, in terms of food security, most of the vegetables are imported. When we use a grammar, when we apply the grammar, when we build a grammar for a specific case study, we can decompose the grammar to analyze different catchments or regions or political divisions, or even climatic areas. Connecting the internal view, which is the viability check, with the external view, the feasibility check, the ecosystem analyses, is very important as we have seen. And it's very important for sustainability analyses as we will see in the next two sections.