MAR planning module

The MAR planning module is a key module of the decision support system. The module consists of two components, namely watershed info (―Basin Edit‖) and ‗Start Planning‘ (Figure 4.7). The ‗Basin Edit‘ function allows the user to enter relevant information of the study area. The water budget information can be stored in the system through the ‗Water Budget Data‘ option (Figure 4.8). The planning module has a tree structure, which appears in the left part of the screen in a windows–like appearance (Figure 4.9). The components of the tree are linked to different analysis techniques, information and modules using the right-hand mouse click option. The planning tree allows the end user to guide through the sequential steps of planning; namely, water source, water quality check, ARS (Artificial Recharge System) location, ARS technology, and option builder. The attributes (e.g., water quantity and quality) of the available water sources (e.g., surface water, treated effluent, imported water etc.,) are implemented at the first step for understanding the overall water availability situation (Figure 4.10) with the status of water quality (Figure 4.11) and for further consideration while making decisions.

Clicking on ‗Planning‘ menu allows to navigate ‗Basin Edit‘(Figure 4.8) and ‗Start Planning‘ options (Figure 4.9)

Figure 4.7: ‘Planning’ menu for MAR planning Module

The system also offers the visualization of time series data in addition to the general advantage of spatial visualization in ArcGIS. The user has the flexibility to add new water sources by clicking on

the map and to work with any type of water sources. The availability of water in the watershed can be added to the system to analyse the water budget quantitatively (Figure 4.10). The water quality check allows the user to compare the water quality of the source with standard water quality guidelines/

Figure 4.8: ‘Basin Edit’ options for the watershed

Clicking on the‘ Basin Edit‘

button the user navigates to an option for entering the basic information of the

Watershed/Basin

Clicking on the ‗Water Budget Data‘, the user opens another window that allows storing and displaying the water budget information of the Watershed

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regulations. The system offers the WHO standard as default for the water quality check. The local guidelines can be compared also in the system.

If the source attends to water quality standards, the system user proceeds with the identification of potential sites for MAR. If the site for MAR system implementation has been already fixed, it can be demarcated in the system with additional general site information asked by the system. If the location is not known, the system offers a method for MAR site selection (described in 4.3.4).

Preferred location-wise MAR Technology is assigned together with the location demarcation. General information such as aquifer thickness, distance from the water sources, use of the injected water, etc. for each location can be saved in the database.

The final step is the definition of a set of alternative MAR planning and management options, supported by the so-called ‗Option Builder‘ under the step ‗MAR planning Options‘ in the planning tree. This step allows the user to define MAR options using the information already given in the preceding steps. Main options components are the water source, MAR location, technology, and annual amount of water to be infiltrated or injected at specific locations. By varying the water source, water quantity, and use of water together with MAR location, the user may generate different MAR project options. These options may be further analysed and ranked based on MCA procedures, given in the decision analysis module. A brief description of the corresponding interface is given under Chapter 4.2.5.

Figure 4.9: MAR ‘Planning Tree’

Figure 4.10: ‘Water Source’ (quantity) attribute in the G-DSS

Figure 4.11: ‘Water Source’ (quality) attribute in the G-DSS

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When the location of the MAR project is not known, the system offers a module which facilitates the user to perform a Spatial Multi Criteria Analysis in order to select potential sites and study their suitability with regards to MAR project implementation (Figure 4.12). The following section gives an overview of the methodology for a site selection tool that was newly developed and describes the interface in details.

A. Constraint mapping

Starting the procedure, the system offers some default criteria to choose and to select the corresponding raster map. New criteria can be added by the user. Both value type and class type map can be handled by the system. The user defines the threshold value for value type criteria and may assign 0 (for non-potential area) or 1 (for potential area) to each class of the class type map. The system then creates a constraint map of each sub-criteria separately (Figure 4.13). The resulting maps may be overlaid and one constraint map can be prepared according to Boolean logic. The constraint maps are added to the ArcGIS document and can be used for further analysis.

Figure 4.12: Navigation of site selection module from MAR planning tree

Figure 4.13: Constraint criteria selection and threshold definition for value type maps (left) and for class map (right)

B. Site suitability mapping

Site suitability mapping starts with the preparation of a hierarchical structure by selecting the criteria and sub-criteria for each level and naming the goal of the analysis. The user selects the criteria from the default list. The default criteria are prepared, considering all relevant characteristics that should be included for spatial analysis. Special care was given to avoid any duplication of the

criteria/sub-criteria in the analysis. New criteria/sub-criteria or sub-criteria/sub-criteria can also be added easily (Figure 4.14). The user can visualize the hierarchical structure and edit for presentation and reporting purposes. The

Figure 4.14: Interfaces showing the criteria selection, hierarchy construction and standardization of the thematic maps

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standardization process follows building of hierarchy. The user selects the criteria, the constraint map, the threshold values, and the preferred standardization function.

The converted function is drawn graphically in the interface for better visualization (Fig 4.14).

Overlay command from the criteria tree proceeds to the step of weighting and overlay. The system offers pair-wise comparison and a direct weighting method. The weights of each criterion in each level can be given directly or generated by pair-wise comparison. By applying the pair-wise comparison method, the user can input preferred values using a scale bar. The weights are generated using the specified formula by Saaty, 1980.

Finishing the weighting procedure, the system user reaches the final steps for site suitability mapping

(Figure 4.15, left). Two different overlay procedures are being offered by the system, Weighted Linear Combination (WLC) and Ordered Weighted Average (OWA). In OWA, the linguistic quantifiers are assigned to each level of the overlay. The resulting map is then created and shown as an ArcGIS document. The Analytical Hierarchy Procedure AHP, according to Saaty (1980), supports the construction of a criteria tree as well as the calculation of relative weights of criteria and sub-criteria by pair-wise comparison. After the AHP function of the program is carried out, WLC or OWA are utilized. WLC computes the overall suitability for each alternative or cells using the standardized map, weights, and constraint map. On the other hand, OWA produces the suitability maps by specifying the linguistic quantifier, (generating a set of ordered weights related to and combining the generated value for each alternative).

Figure 4.15: Overlay for final suitability analysis (left) and reclassification step of the suitability map (right)

By changing the weights of each overlay method and linguistic quantifier associated with the objectives and attributes for OWA, a wide range of decision scenarios can be generated and the corresponding map layers are added to the map document. This helps to check the sensitivity of the system with changing weights and linguistic quantifiers.

The suitability map can be classified as very good, good, moderate, poor and bad.

The system offers five different colors, after Water Framework Directive (WFD), for the five classes (Figure 4.15, right).

The user has the opportunity to change the range of class manually.

The system user may now choose different most-suitable MAR locations according to the location of the available sources of water, taking the required water transfer between sources and selected locations into consideration. The proper technology, such as infiltration pond and or injection well techniques depend on the surface and subsurface condition of the area. The selected most suitable locations will be fixed by using the right click option in the site selection tree and navigating to the positioning of the location on the GIS map (Figure 4.16). The user is asked to give the details of the locations and the technology that will be used at the specific locations (Figure 4.17).

Figure 4.17: Interface showing the input window to include details of the MAR location in the system