An investigation of the effects of GIS model selections on hydrology

by Osman, Nasir Abd

Abstract (Summary)
Water is an essential element for human life, and thus water resources are of great importance. GIS is a relatively new technology that provides solutions to issues related to water resources. The National Hydrography Dataset is designed to provide comprehensive coverage of hydrologic data for the US. While based on l:100,000-scale data, the National Hydrography Dataset is designed to incorporate and encourage the development of the higher-resolution data required by many users. It will also facilitate improved integration of hydrologically related data in support of the application requirements of a growing national user community and will enable shared maintenance and enhancement. Generation of a high resolution NHD dataset for Little Miami watershed is a project carried at the Center for Mapping at The Ohio-State University. Arc Hydro is a geospatial and temporal data model for water resources that operates within ArcGIS. Arc Hydro has an associated set of tools, built jointly by ESRI and CRWR, that populates attributes of the features in the data framework, interconnects features in different data layers, and support hydrological analysis. Three of the five components of Arc Hydro were created for the Lower Little Miami watershed using a DEM created from 7.5 minutes USGS DLG files in Arc/Info. The two GIS data models were investigated from three aspects that affect hydrology: the relationship between feature representation in both models and how they can be linked or integrated; the watershed approach and the GIS automated method for watersheds delineation; and different methods of navigation in the stream network of both models.Results show that there is a correspondence between the features in both models. It is difficult to represent one data model in the format of the other data model. However, the Arc Hydro data model can be linked to the NHD to retrieve the attribute information needed. The new concept of Arc Hydro geodatabsae creation "GIS Object Oriented approach" enhance the abstraction and modeling the water features, and will allow solving the problem of integrating the different GIS databases. The accuracy of GIS in delineating the watersheds from the DEM is not of high however, it is efficient in delineating large areas quickly, when compared with the manual method of delineation. Both NHD and Arc Hydro data models allow tracing of water movement among features of the network and support different kinds of navigation. Navigating the NHD stream network is more realistic as it accounts for features associated with the water system, but that do not have flow records. However, navigating in an Arc Hydro network will allow the user to track the effect of the pollutant particles outside the stream network. Moreover, the capability of next-downstream navigation will allow the user to estimate the flow between selected features.
Bibliographical Information:


School:The Ohio State University

School Location:USA - Ohio

Source Type:Master's Thesis



Date of Publication:01/01/2002

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