Closed Depression Topography and Harps Soil, Revisited.

The Harps soil (Fine-loamy, mixed superactive, mesic Typic Calciaquoll) results from carbonate accumulations around wetland depressions. The purpose of this study is 1) to delineate surface deposition of carbonates representing Harps soil which results from outward and upward flow around closed depressions, and 2) and to relate the carbonate deposits to soil landscape features. The study was based on field-measured soil surface carbonates determined by violent effervescence with 10% HCl. GIS and associated programming was used to determine landscape features and depression depth using a lidar-based 1-m DEM. After initial clean-up of the lidar data, a variable range was used for neighborhood calculations, up to 10 m. The carbonate areas were located primarily in the edges of and just outside the depressions with only 4% located in zones greater than 0.5 m deep in the depression. The carbonate areas were on flatter areas (mean slope of 1.14% compared with median slope of 1.78% for the whole area), and somewhat more convex profile curvatures (-0.25 / 100m compared with 0.46 / 100m for the whole area), especially close to the depressions. Even with tile drainage, the depressions still held water following snow melt and intense rain often for a few days or even weeks. This might have been long enough to continue the outward and upward water flow and carbonate transport pattern.