Multi-purpose dams facilitate human life by purveying water for household purposes, irrigation activities, hydropower generation, and reducing flood risk [1
]. The suitable site of hydro-projects has the least pessimistic environmental impacts [2
]. Therefore site suitability analysis for the construction of the dam is crucial [3
] by considering geographical properties like downstream conditions [4
], lakes [5
], and geological hazards [6
]. Water is one of the essential components of all human activities and supports life [8
]. The distribution of water has been uneven and further disturb by global variability in climate [9
]. Snow and glaciers melting due to the temperature rise have increased the discharge of rivers and the frequency of Glacial lake outburst floods (GLOFs). Similarly, variation in the amount and spatial pattern of rainfall has further intensified the magnitude and frequency of floods in the areas which receive more precipitation and drought in arid regions [10
]. To avoid such a disaster and for the sake of development, dams provide a sustainable amount of benefits to humanity, such as flood risk mitigation, agriculture, and hydropower production [11
]. Pakistan is one of those countries facing problems such as natural disasters, power crises, and water scarcity. Pakistan has been facing power crises for which hydropower projects generate renewable, environment-friendly energy sources. In Pakistan, 21% of gross domestic product (GDP), and 50% of the economy rely on agriculture [13
]. In this regard, water resource management is the most critical issue and need in many countries worldwide [14
]. Spotting feasible sites for the multi-purpose dam is a part of water resources management [1
]. Moreover, building dams has a high fiscal cost; therefore, positive feasibility is necessary.
Multi-criteria decision-making (MCDM) methods can be utilized to solve such problems. MCDM methods use several criteria to make a problem solving decision. There are many MCDM methods and their applications in which the analytical hierarchy process (AHP) is one of the most used methods [15
]. AHP is the most potent and most straightforward technique for solving the most crucial step of MCDM that is defining the weights of criteria [16
]. The main steps involved in AHP are identifying the problem, making a hierarchy of selected criteria, making the pairwise comparison of chosen criteria, and weighing each criterion [17
]. AHP facilitates decision-making under several criteria rather than one criterion [15
]. AHP has been used as a weighting method for Geographical Information System (GIS)-based MCDM in many site suitability applications [18
Previously many techniques have been applied to find potential sites for dams: multi-purpose earth dam sites use AHP [1
]; GIS, which included overlay, polygon intersection, and normalized cumulative weighted index (NCWI) [19
]; GIS spatial analysis for a valley by analyzing its shape, geometrical and bathometric properties [20
]; a geo-spatial information system for small hydropower [21
]; automation of the hydropower site identification process using a GIS-based computational program based on remote sensing and regional streamflow data [22
]; assessment of small dam sites’ suitability based on satellite, climatological, and hydrological freely available data [23
]; dam spots for flood control based on remote sensing (RS) and GIS [24
]. Locating reservoirs with GIS and RS, where two models, Boolean and weighted linear combination (WLC), were comparatively evaluated [25
However, most of the studies used the MCDM approach based on the amalgamation of GIS, RS, and AHP to find a feasible site for suitable dam sites; some of them are [9
]. Therefore, in this study, we put forward a new model, DSSM, based on GIS, RS, and AHP as a weighting method to find potential sites for the multi-purpose dam. As most of the studies [9
] involved stream and surface water as an essential parameter to determine potential sites for the dam as adequate water is vital, which has to be stored and utilized for many purposes. The models used in the previous research gave suitability maps but not directly on the streams according to their order of streams, which is very important. Another aspect is that some studies included stream order as a parameter in overlay analysis. However, the suitability map results were still all over the area, which is not satisfactory. Moreover, high stream order with enough catchment area and a perfect V-shaped valley are also considerable for dams’ cost-efficient development. This research is an effort to improve dam site identification analysis and elaborates on the different results based on stream order. Therefore, stream order is taken as the most crucial factor for this study.
The Panjkora River, situated in the Northwest of Pakistan, has enough capability where the multi-purpose dam can prove beneficial. To achieve this aim, we proposed a new approach named the dam suitability stream model (DSSM), which is based on GIS, remote sensing, and the theory of AHP, where the following objectives given below are set for the model:
To generate suitability maps
To propose multi-purpose dam sites
Evaluate each proposed dam site
In this study, hydro-meteorological, geological, land cover, and geo-morphometric characteristics are analyzed of the Panjkora River Basin and suitable sites for construction of multi-purpose dams. This study involved the essential parameters for dam suitability analysis and evaluation parameters for evaluating the proposed dam sites. Among the essential parameters of the model, stream order is crucial to ensure enough water availability that can be stored by the dam for many purposes. This study systemized the entire location analysis process by developing the dam suitability stream model (DSSM) by utilizing GIS, RS, and AHP, while enhancing the findings’ accuracy.
The model gave two types of suitability map, which were further analyzed, and we proposed two final dam sites. The proposed dam sites are in the upper reaches that fulfil the multi-purpose. Lower reaches consist of more settlements, e.g., Timergara is the central city in the lower reaches. As every river consists of the population living near the river, which is essential for life, but dam sites can also provide different benefits to the area, e.g., fishing industry, use of water for the marble industry, etc. Moreover, lower reaches are also a high flood hazard zone [38
]. In 2010, a destructive flood disaster caused many deaths and economic losses, especially in the lower reaches. Therefore, the construction of these sites will prove to reduce flood disasters. Another advantage is the provision of water in the lower regions for agricultural production. The selection of these sites is considered the dam’s purposes, and all the parameters are analyzed to obtain the best possible area and conditions.
However, some parameters have not been taken into account that can influence the site suitability performance, such as economic performance, site accessibility, etc. The developed technique can be utilized alongside traditional approaches to ascertain new dam construction locations to increase efficiency and save time and resources. Future research can focus on high-resolution DEM, high-resolution satellite and aerial images, and advanced methods such as machine learning and deep learning to retrieve the model’s parameters in order to strengthen the model’s accuracy.
A new model DSSM is being proposed in the current study based on integrating GIS, remote sensing, and AHP to spot a feasible site for constructing a multi-purpose dam in the Panjkora Basin, northwest of Pakistan. The selection of sites for multi-purpose dams involves several factors. Therefore, DSSM can utilize all factors combined with streams and their order in an efficient way to solve this problem. DSSM uses AHP to assign weights for each criterion, where the highest weight is given to the most crucial parameter of the DSSM model, named as stream order.
Overlay analysis aggregates all the essential parameters in the form of raster maps with their concern calculated weights that resulted in the suitability maps. The results showed two types of suitability map, i.e., “suitability on stream” and “overall suitability” based on stream order and Euclidean distance (distance from streams), respectively. Each of the maps showed four suitability classes (highly suitable, moderately suitable, less suitable and least suitable). Two sites were proposed based on the first suitability map for multi-purpose dam construction, and each site is evaluated in a GIS environment using evaluation parameters.
The proposed sites are feasibly located where the whole region of the Panjkora river basin will yield multi-benefits such as flood reduction, water for agriculture, fish industry, and hydropower generation. Developing countries like Pakistan badly need such initiatives where an extensive amount of water is being wasted and causes disasters.
For further studies, it is recommended that high-resolution datasets will increase the accuracy of the study. Other parameters with streams and their order can also be included to improve model efficiency, depending on the area and analysis conditions.