The origin and identification of macropores in an earthen-lined dairy manure storage basin

Earthen-lined basins have been used to store dairy manure in Wisconsin since the early 1970s. Monitoring data indicate that many of these basins are leaking, but little effort has been directed toward explaining the mechanisms responsible for leakage. Morphological and micromorphological techniques were used to identify macropores in the sidewall of an earthen-lined manure storage basin. Laboratory and field dye studies provided evidence of contaminant movement via macropores. Results indicate that physicochemical and biological mechanisms were responsible for creating macropores capable of providing pathways for preferential flow. These mechanisms, and the resulting macropores, can significantly affect the long-term viability of earthen-lined manure storage basins.