Abstract:

Water quality parameters such as dissolved oxygen, calcium, water temperature, pH, and turbidity have been used to assess the health of a water body. These parameters are commonly sampled at point locations that represent only a local phenomenon. Based on the kriging analysis and methods of geographic information system (GIS), this study developed modeling procedures to investigate regional water quality of Lake Erie. Data of dissolved oxygen, water temperature, and calcium, obtained from the Intentional Joint Commission, were sort in terms of time and water depth. Then, the analysis of semi-variogram were conducted assuming water quality data are regional variables. Appropriate semi-variogram models were fitted with a 95% confidence level. Results of the kriging analysis based on fitted models were spatially expressed as grid vector values. Finally, a conversion vector values to a raster format resulted in regionalized images showing spatial characteristics of water quality in terms of time and depth, where map algebra were performed. Based on the study, the following conclusions are made: (1) a GIS graphical representation shows that an increase of calcium from the southwest to the northeast of the lake; (2) images of dissolved oxygen as percent saturation obtained by map algebra reveal a decrease of dissolved oxygen distribution from the northeast to the southwest region; (3) the ambient temperature during summer months intensifies the stratification between the warm waters of epilimnion and cool waters of hypolimnion. KEY WORDS: Dissolved Oxygen, Water Temperature, Calcium, GIS, Kriging.

1. Professor, Civil Engineering Department, 147 Stocker Center, Ohio University, Athens, OH 45701.

2. Former Graduate Assistant, Civil Engineering Department, Ohio University, Athens, OH 45701.

Water Resources Engineering Conference
August 1998

For more information on this or any other paper contact Terry Chang by email at tjchang@bobcat.ent.ohiou.edu