Using GIS to estimate lake volume from limited data

Estimates of lake volume are necessary for calculating residence time and modeling pollutants. Modern GIS methods for calculating lake volume improve on more dated technologies (e.g., planimeters) and do not require potentially inaccurate assumptions (e.g., volume of a frustum of a cone), but most GIS methods do require detailed bathymetric data, which may be unavailable. GIS technology cannot correct for a lack of data; however, it can facilitate development of methods that better use the relatively simple and more widely available measurements of lake shape and maximum depth. In this research note we describe a method to model bathymetry and estimate lake volume with a limited set of data that consists only of a maximum depth measurement and a GIS layer of lake shoreline. Using a simple linear transformation, we estimated depth as a function of distance from shoreline and with the resultant information estimated lake volume. We applied and compared this method with estimates derived from field bathymetry data of 129 lakes in New Hampshire. In New Hampshire lakes, the assumption of depth as a function of distance is appropriate, and the simple GIS method has lower overall error than simply using the formula for volume of a cone to estimate lake volume. This approach has broad implications in the assessment of lake condition from national surveys (e.g., US Environmental Protection Agency's National Lakes Assessment) and should improve upon models of nutrients, contaminants and hydrology, even in the absence of detailed bathymetric data. Supplemental materials are available for this article. Go to the publisher's online edition of Lake and Reservoir Management to view the free supplemental file.