Locating the artificial feeding of underground water by comparing watershed management, irrigation and geology

Dissertation for Master's Degree in Natural Resources Engineering - Watershed Management

Abstract

After glaciers and ice sheets, underground water sources form the largest reserve of fresh water on earth and are one of the most important sources of fresh water supply needed by humans. Since in most parts of the country, rainfall is often insignificant and sometimes appears as destructive floods, artificial groundwater feeding operations can be used as a suitable solution for the optimal use of floods and the stability of underground water tables. Determining suitable areas for artificial feeding is very important and must be done carefully. Due to the presence of many effective parameters in positioning and the need to examine the evaluated criteria and their continuous changes, the geographic information system is an effective tool for managing and using spatial data in this field. In this research, the factors of slope, water quality, depth of underground water and geological units were used to locate suitable areas for artificial groundwater feeding in Dasht Khoi in northwest Iran. The above maps were integrated in the GIS environment and by applying the hierarchical analysis method. In this study, in order to compare the criteria and sub-criteria effective on artificial nutrition by preparing a questionnaire from the viewpoints of watershed, irrigation and geology experts, 16, 13 and 12 respectively were used and the results of each were examined separately. Also, the land use map of the region was also extracted from Landsat 8 satellite images in order to apply existing land use restrictions in the region, and after superimposing the final layer with a buffer of 50 and 100 meters for water-filled waterways with rank 3 and 4, the results of the research showed that according to each of the watershed, irrigation, and geological experts' views, about 48.00, 38.11, and 7.76 hectares, which include 39, 81 and 14 polygons are suitable for artificial feeding in Dasht Khoi area.

Key words: Dasht Khoi, location, artificial feeding, hierarchical analysis process, watershed management, irrigation, geology.

Chapter 1: Introduction

At the same time as the population increases, the need for safe and drinkable water has been on the rise, and on the other hand, surface water sources are also facing the problem of pollution and volume changes over time, as a result, the planners' eyes have shifted towards underground water sources, which are considered vital water sources in arid and semi-arid regions. After glaciers and ice sheets, underground water sources constitute the largest freshwater reserve on earth and are one of the most important sources of human freshwater supply (Freeze & Cherry, 1979). The need to know and optimally use underground water comes from the fact that these resources make up 99% of all available fresh water (Kowsar, 2014). In addition, in many countries located in arid and semi-arid areas, more than 80% of water resources are used (Sadaqt, 1372).

In recent years, with the increasing population, development of industry, growth of urbanization and the consequent increase in demand for food, the exploitation of water resources is many times higher than in the past, so that the amount of exploitation and consumption of underground water is more than the amount of nutrition of these resources. is, in other words, the input of the underground water system is less than its output, and the system with a negative balance has a positive feedback and is decaying; Therefore, it is very important to identify and determine the most suitable place for this purpose. The management of water resources is a set of many management actions aimed at the optimal use of water resources and reducing economic, social and environmental damage. Iran is considered one of the arid and semi-arid regions of the world due to its special geographical location and very scattered unevenness and climatic conditions and the state of atmospheric precipitation. But the same amount of rainfall is not well distributed in time and place. So that one-third of the rainfall falls in more than half of the country (in the central desert) and one-third falls on a level of about 10% of the total area of ??the country and the rest falls in other parts (Asgharpour, 2013). In this sense, the limitation of water resources has been the concern of Iranians for a long time.Considering that underground waters make up 99% of the total usable fresh water (Akbarpour, 2018) and on the other hand, many regions of our country are arid climates in terms of climate, they provide a large part of their water supply from underground sources. Depletion of underground water and the lack of replacement of water from these sources is one of the biggest problems that human societies, especially our country, are facing.

One ??of the ways to solve the challenges related to the negative balance of underground water is to study and implement artificial nutrition projects in areas that are facing problems due to this. Artificial feeding of aquifers is one of the methods that can replace part of the water coming out of the basement. Artificial feeding is the addition of water to underground water sources (Sultani and Abedi, 2018) or the introduction of water into a permeable formation with the aim of feeding the underground water table and in order to reuse it with a different regime and quality that is created by creating additional facilities or changes in the natural conditions of the region (Habibi et al., 2019). The meaning of this definition is the addition of any water to the aquifer regardless of its origin.

In order to model and manage water resources, it is necessary to determine the net supply of underground water. The use of underground water is very important for expanding urban, industrial and agricultural areas, especially in arid and semi-arid areas (Xu & Beekman, 2003; De Vries & Simmers, 2002). Groundwater feeding is an important part of the hydrological cycle. Feeding can be done directly by spreading water in wide pits and directing water in injection wells or indirectly from human activities such as land irrigation. The use of computer and mathematical models, the management of underground and surface water resources and the transfer of pollution to underground water resources require a proper understanding of the concept of nutrition (Neff et al., 2006). To achieve a certain goal, there are several solutions, each of which provides different priorities for different issues such as environmental, social, political and organizational. These requirements naturally lead to the use of multi-criteria decision-making methods (MCDM[1]), whose purpose is to choose the best solution from among different solutions.

Analytic Hierarchy Process (AHP[2]) method is widely used as a multi-criteria decision-making technique (decision-making system) in the field of location. Considering the problems related to the decision-making process based on multiple criteria, it can be said that the decision-making process is not simple and due to the lack of standards, the speed and accuracy of decision-making is greatly reduced. This makes the decision-making process highly dependent on the decision-maker. To solve this problem or to minimize its side effects, multi-criteria decision making (MCDM) methods have been designed. Analytic Hierarchy Process (AHP) is one of the most comprehensive systems designed for decision making. This technique provides the possibility of formulating the problem in a hierarchical manner and also allows the consideration of different quantitative and qualitative criteria in the problem. In this method, different options are involved in decision-making and there is a possibility of sensitivity analysis on criteria and sub-criteria. It is also based on pairwise comparison, and this issue facilitates judgment and calculations. In this method, the degree of consistency and inconsistency of the decision can be calculated, which is one of the exclusive advantages of this technique among different methods of multi-criteria decision making. The analysis process is designed in a way that matches the mind and human nature (Qodsipour, 2019).

Artificial nutrition can be done in several ways, in the division made by Scanlon[3] and colleagues in 2002 to quantify nutrition, nutrition was classified as surface studies, studies of saturated areas, and studies of unsaturated areas (Xu & Beekman, 2003; Scanlon et al. al., 2002), also Beldachi et al. (2009) divided the artificial feeding methods into three surface methods (special pools, Farrer, river bed, flood spreading, ice water irrigation, Degar, Torkinset, underground dam and pitting), well feeding and induction feeding or feeding by lowering the underground water level. The best possible use of water resources requires determining the right place to implement artificial feeding plans.