Helping Livestock Producers Fulfill Environmental Standards
Permeability and seepage tests are conducted on new and existing lagoons to ensure the lagoons are meeting all groundwater statutory and regulatory requirements.
Most lagoons are built with compacted soil liners designed to keep seepage rates within mandated guidelines. Facilities must show that the proposed design, materials, and construction practices are such that the expected engineered seepage rate will meet the standard.
Overnight Water Balance/Whole Pond Test
This test uses two pressure transducers to measure the drop in water level over time to the nearest ten‐thousandth of a millimeter. A weather station is also brought to the site during the test, so we can determine which fraction of the drop in water level is due to evaporation and which fraction is due to seepage through the structure’s liner. The test is conducted on two consecutive, or near consecutive, nights to reduce uncertainty.
SEC can collect core samples from new lagoons before putting them into service. The procedure includes obtaining a cylindrical core sample, usually three inches in diameter and to a depth of one foot. The core is then sent to a laboratory for analysis to determine the seepage rate. The core samples are also used to test the seepage rate of mortality composting pads.
The standpipe test is generally used to determine the seepage rate of settling and sediment basins. It is completed by installing a six‐foot-long pipe verticality into the structure’s liner to a depth of one foot. The pipe is filled with water and allowed to come to equilibrium. It is then filled again with water. After three days, the drop in water level is measured and used to determine the structure’s seepage rate.