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Development of GIS Interface Tool for GAMES Model

GIS Interface

Soil erosion is an important economic and environmental GIS Interface concern throughout the world. In order to assess soil erosion risk and conserve soil and water resources GIS Interface , soil erosion modeling at the watershed scale is imperative. The Guelph model for evaluating effects of Agricultural Management System on Erosion and Sedimentation (GAMES) is tailor-made for such applications; it, however, requires a significant amount of spatial information which needs to be pre-processed using a Geographic Information System (GIS). The GAMES model currently lacks any such automated tools. As such, the GAMES was loosely coupled to a GIS interface to manage the large spatial input data and to produce efficient cartographic representations of model output results. The developed interface tool was tested to simulate the Kettle Creek paired watershed in Southern Ontario, Canada. Result demonstrated that the GIS-assisted procedure increased the ability of the GAMES model in simulating such a spatially varied watershed and made the process more efficient and user-friendly. Furthermore, the quality of reporting and displaying resultant spatial output was also significantly improved. The developed GAMES interface could be applied to any watershed, and the enhancement could be used to assess soil erosion risk and conserve soil and water resources in an effective way.

Prior to the use of the computer-based hydrologic model and Geographic Information System (GIS) in hydrology and hydraulic projects, practitioners assembled a number of maps, imageries, stream network, and other relevant data from field surveys to perform manual preliminary hydrologic analyses such as catchment delineation [1][2]. These manual methods were very laborious, time-consuming and inefficient [3]. The advancement in GIS technology, digital spatial data, and efficient computers has precluded the need for many of these labor-intensive techniques [4]. Developments in the field of GIS helped users to organize all forms of geographically referenced data as layers and various GIS software/tools such as the ArcGIS [5], enabled hydrologists to pre-process, view and analyze project-specific digital elevation model (DEM), soil, land-use, and hydro-meteorological data spatially [6]. Besides, several hydrologic functions are in-built to perform some of the preliminary investigations which have reduced the level of approximation and subjectivity involved [7]. Use of GIS technology in any hydrology project significantly improved the quality, accuracy, and timeliness of the final product [8]. Furthermore, GIS greatly simplifies the model set up and improves model performance [9]. Additionally, the GIS advancements enabled users to handle a large amount of data in a short time frame.

Another critical component of GIS is an enhancement of the visual understanding of the spatial inputs and output results by managers, decision-makers and the public-at-large [10]. Changing the inputs of land use or introducing best management practices (BMPs) to compare the subsequent output can be very helpful to identify the problem and ease the decision-making process. Similarly, specialized interfaces when linked to a GIS application have increased the popularity and usability of spatially distributed hydrological models and led them to greater use and wide acceptance [11].

Developments of GIS interface for the hydraulic/hydrologic model started in 1975 when the HEC-1 model was integrated using a grid-based model. The resulted model was named as HEC-SAM. In this approach, the GIS software was simply used as a database to feed input data to the model [12]. There are several different approaches to integrating GIS with simulation models such as; the embedding method, loose coupling and tight coupling methods [13][14][15][16]. The loose coupling approach is the simplest as the GIS software and the hydrologic model exchange files, read some of its input data files from geo-database and produce resultant output in a format that allows processing and displays the results within the GIS software. This is a standard approach since it requires little or no modifications to model software [17][18]. From the successes of the past two decades, hydrological modelers have recognized the benefits of integration of GIS software and hydrological models [19][20]. The advancement in GIS technology and improved techniques for the integration of GIS with hydrological modeling has made hydrological models more efficient and user-friendly [21][22][23][33].

The Guelph model for evaluating Effects of Agricultural Management Systems on Erosion and Sedimentation (GAMES) [24], developed at University of Guelph, Guelph, Ontario, Canada, is seasonal event-based soil erosion and sediment yield simulation model for analyzing watershed management practices and effects on nonpoint source pollution changes [25]. However, it was not coupled with any GIS tool. As such, model inputs at user-specified spatial units were not automated which made the model difficult and inefficient to use in areas with high-resolution spatial maps. Furthermore, analyses of model outputs which could greatly be enhanced with the use of any GIS platform was hampered. The GAMES model thus needed a much-needed upgrade in this respect. In this research, a GIS interface modeling tool has been developed which involved two distinct phases. This is the first attempt of this kind specifically to the GAMES model and hence is a novel work. In the first phase, the GAMES model was loosely coupled to a GIS interface by developing a GAMES-GIS model in a GIS system. Then, a GAMES input data generator model was developed in Microsoft Excel using the Visual Basic code in order to convert the processed GIS data in a format compatible with the input format of the GAMES model.

In the second phase, the previous two steps process with many manual-based sub-processes were automated by creating a user-friendly computer interface using C# language. During these processes, no change was made in the source codes of the GAMES model. Hence, the main objective of this study is to present the development and evaluation of the GIS interface to the GAMES model in an agricultural watershed in Southern Ontario, Canada. This has resulted in enhancing the capabilities of GAMES model and making it more efficient and user-friendly.