Spatial analysis of suitable areas for artificial nutrition based on the method of FUZZY-AHP (case study: Minab study area)

In recent years, extraction of groundwater resources as well as droughts in the Minab plain of Hormozgan province has led to a decrease in groundwater levels, a decrease in water quality and subsidence, resulting in social and economic problems for the people of this region. On the other hand, in some seasons, due to the flooding of the plain, large surface waters flow into the sea. Considering these issues, it is necessary to find suitable fields for artificial nutrition of the groundwater resources of the plain of Minab, so that artificial dams can prevent these waters and floods from entering the sea. Thus, they could feed the plain of Minab. This research studies Minab as a pilot to identify effective parameters and their use as indicators for determining the susceptible sites and ultimately determining the appropriate arenas for artificial nutrition using ArcGIS, Expert Choice and FUZZY -AHP.

a) Introducing study area
The Minab study area, as part of the Minab Plain, is located 100 km east of Bandar Abbas. This zone, with the code 2807, is one of 22 study areas in the central areas of the river basin between Bandar Abbas to the south, and is geographically located between the geographical longitudes '48 ° 56' and '15 ° 57 'east and the latitudes '00 ° 27 to '20 ° 27' north and east of Hormozgan province. The extent of the Minab study area is 654 km2. Minab aquifer, with an area of 272 square kilometers is the only aquifer in range. According to the summary of the changes in the size of the reservoir of Minab plain, a reservoir deficit of 8.876 (million cubic meters) and an annual water loss of 0.46 (m) for this plain are observed.
b)

There are various ways to locate suitable areas for artificial nutrition. The use of any method involves the integration of different information together and analyzing them. In addition to library studies, in order to identify effective parameters and use them as indicators for determining the susceptible sites and finally determine the appropriate arenas for artificial feeding, Arc GIS, Expert Choice and FUZZY-AHP were used. The steps of the FUZZY-AHP method in this study are summarized as follows:1. Determine the criteria and sub-criteria (layers and sub-layers).
2. Provide and prepare information layers.
3. Preparation of a questionnaire (Delphi method).
4. Weighing of information layers by AHP method.
5. Apply the final weight to the criteria.
6. Fuzzy Overlay Layers Integration.

Regarding effective factors in determining the areas of artificial feeding of the studied area, the research findings show that the geological criterion has the highest score (0.450) in prioritizing the effective parameters in artificial feeding of the plain area of the study area and, respectively, land use criteria (0.260), Hydrology (0.153), topology (0.079) and finally climate (0.058) have the lowest weight in prioritizing effective parameters. After mixing the layers with fuzzy method, a final layer was used to determine the proper places for artificial feeding. The final map was classified into 4 classes (inappropriate, medium, appropriate and very appropriate). The most common areas (49.55%) were inappropriate places, followed by a 21.7% of the middle class, 19.58% of the appropriate, and 9.17% of the very appropriate surface area for artificial nutrition.

The level of water change during the 30-year period was 13.85 m (13 m decrease in water level), which reduced groundwater levels, reduced water quality, caused subsidence and as a result created social and economic problems for the people of the area. Considering these issues, one of the most useful ways to preserve the discharge and maintain the groundwater resources of the area is artificial feeding system which, in addition of compensating for the excessive loss of aquifer and its rehabilitation, will attract the floods and reduce their destructive effects. According to the findings of the research, northwest and areas from the west of the study area of Minab, are the best places for artificial nutrition, accounting for only 9.17% of the total area of the range. The central parts of the research area are ranked appropriately and moderately appropriate, which are the next candidates for artificial nutrition. Inappropriate condition density is also seen in the east of the range.