Author

Cheng Aidong

Date of Graduation

Spring 2008

Degree

Master of Science in Geospatial Sciences

Department

Geography, Geology and Planning

Committee Chair

Robert Pavlowsky

Keywords

the James River Arm, water quality, turbidity, interpolation, accuracy

Subject Categories

Hydrology | Water Resource Management

Abstract

The James River Arm (JRA) is one of the most nutrient-contaminated areas in Table Rock Lake (TRL). Reduced water clarity and quality in the lake have been causing public concern. The problem with clarity is caused by increased amounts of nitrogen and phosphorus entering the lake. Turbidity, or the degree to which light traveling through a water column is scattered by suspended particles, is one of parameters utilized to measure water clarity. To accurately assess the risk and analyze the possible sources of nutrient pollution, interpolation techniques can be used to predict the spatial distribution of turbidity within the lake system. Interpolation is the procedure of predicting the value of attributes at unsampled or missing sites from measurements made at point locations within the same area. Turbidity samples were collected at the confluence of James River and Flat Creek. Using an interpolation model, a continuous turbidity surface can be created from the sampled discrete points. To find the best interpolation model in this specific water quality research, five interpolation techniques of inversed distance weighting (IDW), radial basis functions (RBF), ordinary kriging (OK), universal kriging (UK) and co-kriging (CK) are tested on their statistical accuracy. Comparing the root mean square error (RMSE) of each model, UK was found to be the most accurate interpolator in this study.

Copyright

© Cheng Aidong

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