Our results indicate that when considering the rapid transmission of microbes to ground or surface waters, the nature of the soil hydraulics should be considered as well as the conventional theory of direct entry via the slot of a mole drain.
Anecdotally, within Southland, this type of drainage system has often been blamed for rapidly delivering microbial contaminants to waterways by removal of surface water to mole drains via the rip line or slot of the mole plough.
Mole drains are commonly pulled above the fragipan to help drain the upper profile, and our lysimeters penetrated down to just above the fragipan.
We suggest that on-farm irrigation practices, if not carefully controlled, could lead to significant movement of microbes to shallow groundwater and surface waterways because of rapid transport of microbes through larger soil pores even without considering the preferential flow paths generated by the slot of mole drains.
This discrepancy may result from the assumption of an initially well-mixed soil system to mole drain depth, whereas the actual soil [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] concentration on 28 May 1990 decreased with depth.
A simplified analysis of soil water flow to a mole drain.
Two models for the leaching of a non-reactive solute to a mole drain.
executive Charlie Murless, the mole drains were put down after the big
After a group of trainers emerged from the stewards' room, Dermot Weld said: "The mole drains collapsed and the track isn't safe for racing.