Physical, Chemical, and Mineralogical Properties of Soils

Abstract

Soils used for constructing ponds originally occurred at or near the land surface. Some were well-drained soils, and others were situated in wetlands and covered with water all or part of the time. There are three basic types of aquaculture ponds: watershed ponds, levee ponds, and excavated ponds.¹ Watershed ponds are formed by making embarkments across natural watercourses to impound runoff. Soils for building embankments may come from both inside and outside the areas that will become pond bottoms. Surfaces of pond bottoms may be the original land surfaces with vegetation removed, or the original land surfaces may be cut to obtain fill material for embankments and subsurface soil layers exposed. Sometimes, where topography is irregular, depressions in bottoms may be filled to prevent excessively deep areas. Final pond bottom surfaces will be compacted. Levee ponds are constructed in fairly level areas, and fill material for levees usually is cut almost entirely from pond bottom areas. Bottoms of new levee ponds are normally subsurface layers of soil that have been compacted. Excavated ponds are made by digging pits, and pond bottoms are formed by compacting subsurface layers of soil. Where site soils are highly permeable, clay may be hauled in from other areas, spread over bottoms, and compacted to form barriers against seepage in watershed and levee ponds. Bottom soils of such ponds may have physical and chemical features much different than those of native site soils.