Selected results from an application of ANN within the frame of a water management system over 60 years are presented in
Figure 8. Optimal values of the decision variables for a more profit oriented management scenario have been estimated in order to manage the agricultural production in the coastal arid region which is infected by saltwater intrusion. Considering the trade-off between the two contradicting objectives of profit and sustainability, an overall 60-year profit was estimated to be $158,118 and the value of

was 0.1714. The estimated profit is quite significant for the particular application concerned and the value of

also indicates that the groundwater system will remain in an almost sustainable state at the end of the management period. As is seen, cropping of maize is suggested throughout the whole management period (
Figure 8(b)). The salinity increases twice in 60 years but with small peaks (
Figure 8(d)). At the end of the management period, it achieves a very low value which means that the groundwater system is sustainable. The algorithm increases the extraction rates from the 12th year to almost the 27th year and then again from the 36th year to the 47th year (
Figure 8(c)). The increased extraction rates also correspond to the increased cultivated area (
Figure 8(a)) and the increased profit (
Figure 8(e)). The yield of maize (salt-sensitive crop) increases with the decrease in salinity and vice versa (
Figure 8(f)). Table 8 shows the optimal parameter set for this scenario where each row corresponds to a time period of 12 consecutive years. This scenario can be adapted to a real life problem since it has reasonable trade-off between the two contradicting objectives of profit and sustainability.
Table 8Optimal values of the decision variables in the profit-oriented long-term management scenario
Cropping pattern (fraction of maize)
. | Extraction rates (Mm3/year)
. | Cultivated area (hectare)
. |
---|
1 | 50 | 4.85 |
1 | 274 | 26.57 |
1 | 106 | 10.25 |
1 | 139 | 13.51 |
1 | 50 | 4.85 |
Cropping pattern (fraction of maize)
. | Extraction rates (Mm3/year)
. | Cultivated area (hectare)
. |
---|
1 | 50 | 4.85 |
1 | 274 | 26.57 |
1 | 106 | 10.25 |
1 | 139 | 13.51 |
1 | 50 | 4.85 |
Figure 8
Selected results from a long-term (60 years) optimization run for a profit-oriented management scenario at a specific farm location.
Figure 8
Selected results from a long-term (60 years) optimization run for a profit-oriented management scenario at a specific farm location.
Close modal