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Applications of geographic information system data in the UBC Watershed Model

University of British Columbia

The suitability of using geographic information system (GIS) data to describe a watershed for the UBC Watershed Model is investigated. A GIS combines the ability of a database management system to store, retrieve, and analyse information with the capacity to produce and manipulate graphical elements on a map. In hydrologic modeling, information from a GIS is commonly used to describe the physical characteristics of a watershed such as terrain, forest cover, and soil type. By using a GIS, possible sources of human error and subjectivity present when manually measuring attributes from maps or aerial photographs can be removed. The Seymour Watershed located north of Vancouver, B.C. is used as an example in assessing the value of GIS data for the watershed model and to illustrate the complexities of calibrating the model. Terrain, ecological, and timber GIS databases for the Seymour Watershed are used to create a watershed description file (WAT) which is implemented in the model to produce synthetic watershed hydrographs. These hydrographs are then compared and calibrated against recorded historical streamflows, resulting in a calibrated Seymour Watershed model. This model is then used to forecast future streamflows when meteorological forecasts are also provided. Although GIS data is not perfect, it is valuable in describing a watershed as input for the UBC Watershed Model, which is then used to produce calculated hydrographs. The main drawback of utilizing a GIS for the Seymour Watershed is the absence of adequate documentation of some GIS characteristics. Despite the removal of subjectivity and human error by using GIS data, inaccurate model streamflows remain due to errors in other non-GIS data such as improper reservoir elevation readings, missing historical streamflow or meteorological data, and inherent errors in the watershed modeling process.

Thesis/Dissertation

application/pdf

2009-02-14

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http://hdl.handle.net/2429/4585

Civil Engineering

University of British Columbia

UBCV

DSpace