Soil Analysis:

Excessive seepage in ponds is generally due either to a poor site--that is, one in which the soils in the impounded area are too permeable to hold water--to improperly constructed levees or dams, or to physical damage caused by tree roots, burrowing rodents, or other factors. Selecting a poor site is often the result of inadequate preliminary site investigations and is, therefore, an avoidable situation. You can avoid improper construction just as you can avoid the establishment of trees and shrubs that develop root systems that undermine the dam.

This is why at Catskill Pond the first steps to a successful project is an complete Soil Analysis using test holes and field study to determine the composition of the pond site soil.

Contact Catskill Pond for a complete Soil Analysis and site evaluation before the bulldozer makes the first tracks at your site. Up front planning and analysis can save you thousands of dollars and avoid the horrors that we have been asked to fix that were created by other "Pond Builders".


Minimizing seepage is key to a successful Pond project. There are several methods available:

Compaction
Some pond areas can be made relatively impervious by compaction if the material has different particle sizes--small gravel or coarse sand to fine sand--and enough clay (usually 10 percent or more) and silt to effect a seal. This is the least expensive method of those presented in this website. Compaction, however, is limited to these specific soil conditions and by the depth of water to be impounded.

Bentonite
Adding bentonite is another method of reducing seepage in soils containing high percentage of coarse-grained particles and not enough clay. Bentonite is a fine-textured colloidal clay. When wet, it absorbs several times its own weight of water and, at complete saturation, swells to as much as 8 to 20 times its original volume. Mixed in the correct proportions with well-graded coarse-grained material, thoroughly compacted, and then saturated, the particles of bentonite swell until they fill the pores to the point the mixture is nearly impervious to water. Upon drying, however, bentonite shrinks to its original volume resulting in cracks; therefore, sealing with bentonite is usually not recommended for ponds in which the water level is expected to fluctuate widely. A laboratory analysis of soil particle size distribution is required to decide the rate of application.

Waterproofed Linings
Using waterproofed linings is another method of reducing excessive seepage in ponds with coarse-grained and fine-grained soils. Polyethylene, vinyl, butyl-rubber membranes, and asphalt-sealed fabric liners are gaining wide acceptance as linings for ponds because they virtually eliminate seepage if properly installed.

Chemical Additives
Because of the structure or arrangement of the clay particles, seepage is often excessive in fine-grained soils. If these particles are arranged at random with end-to-plate or end-to-end contacts, they form an open, porous, or honeycombed structure, and the soil is said to be aggregated. Applying small amounts of certain chemicals to these porous aggregates may result in collapse of the open structure and rearrangement of the clay particles. This dispersed structure reduces soil permeability. The chemicals used are called dispersing agents.