The conceptualization phase describes the analysis in which the basis (qualitatively) of the system is defined. The considerations that we will have in this phase will be the determination of the model boundaries, the creation of causal diagrams to describe the system behavior and the identification of important variables of Azag Strip system.

System Boundaries

In order to have the appropriate insight of the system, it’s necessary to identify the main forces that intervenes in the case and that will influence the behavior of the system. In order to find out which are those forces, we find useful to describe the case with the following system diagram.

From the following drawing we can identify that there are some external forces like Political instability, Geography, Weather and Population Growth with can’t be control by the government, which are part of the external factors. Then we have identified some government policies like the maximum pumped water from Groundwater and the abroad water policy and the concentration of Nitrate on used water that can be influenced by the government. At the end we identify the output of our system which are the groundwater quality, quantity and available water for users (supply water).

The system is categorized into sub systems, which are main driver inside the system. We found that the population affects the allocation of land use, determines the water demand, and affects the quality and quantity of the Groundwater, considered the main water resource of Azag Strip. In order to explain the relation among them,causal models are developed.

Basic Causal Diagrams

In order to have a close insight of how all the sub systems are interrelated, causal diagram  is prepared in where we are considering the most important cause-effect relations, which explains what can change the existing behavior and the system dynamics.

In the causal diagram we will find that some assumptions were required for the creation of the system and that are explained below. Like this assumptions, there are other factors that will have an important effect on our system behavior and that will be checked in the verification and during the use of our model.


  • The births in Azag Strip in the future will be stable (around a 60% of the total population), as the people may hope to ensure a comfortable old age by having many children that take care of them.
  • The deaths in Azag Strip will have the same trend as the births (fluctuating around 5.5% of the total population), as the medical care has improved with an increase in investment in the medical sector.
  • There is an increase in the unemployment index with an annual growth of one percent.
  • The Net Migration will be mainly influenced by the possible existing water shortfall per capita; in the case that water supply won’t cover the increasing demand.
  • The water that seeps from domestic cesspits and irrigation goes to the groundwater with nitrate, which mainly affects the quality of the groundwater. The concentration on these waters are almost 350 mg/l of used water.
  • The groundwater is collected in a ground layer with 5% of porosity.
  • The land designated per house is almost constant around the country with 285 m2 per house.
  • In average, the sizes of the families in Azag Strip are 7 persons in family.
  • The water demand of domestic sector is increasing by 0.5 m3 per capita.
  • The water demand of the industrial sector appears to be constant at 240 m³ per employee in the industrial sector per year.
  • The irrigated sector is divided in donum with an average of 1000 m2 and the yearly demand for irrigation per donum has been reduced from 700 m³ to less than 500 m³.
  • The government has established a policy for bringing water from abroad that will cover the 10% of the total water demand.
  • There will be a maximum of 100 million m³/yr of water that can be extracted from groundwater.
  • A special consideration for this model was that the seepage water from Rain, Domestic Use and Irrigation which will not have a delay reaching the groundwater table and only the Nitrate in the last to inflows will have a Delay of 10 years. This assumption is been considered as this cycle of water (inflow and outflow of water) had already started before 1975.

Because we are managing a complex system in where many aspects of the real world of Azag Strip are taken into account and have divided the causal drawing in small representation of the system, which are indicated in the links below.

Inside the system we can find that some accumulations and feedbacks occur. For an example of feedback we can see that the population has a two way causality existing between the births, deaths or net migration and the Total Population. In this cases, the increase in the population affects the number of births, deaths and net migrations that consequently determines an update of the total population. In the case of the births, it is a positive feedback, and in the case of the deaths and the net migration it is negative feedback. The sign of the feedback can be determined by multiplying the signs of all the connections inside the feedback loop.

In the case of the groundwater we have identified it as a accumulation of different inflows coming from rain water, water used in irrigation and water used in households. All these waters came into through the ground until they reach the groundwater. The only water that comes out is the pumped water for covering Azag Strip demand of water as it’s the main source of water.

Like such examples, we can find more information by analyzing these qualitative diagrams. In order to know if the causal diagrams gives a complete view of the system, we have evaluate the qualitative representation of the system and by introducing the units of how they will be measured (for each criteria), we can know more about the quantitative representation of the whole system.


Identification of important variables

1.  Population

2. Land Use
         Urban Areas
             Housing Area
             Business Area
         Agriculture Areas
              Irrigated Area
              Non Irrigated Area

3. Total Water Demand
              Domestic Water Demand
              Industrial Water Demand
              Agriculture Water Demand

4.  Total Water Supply
5.  Groundwater







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