Concern has been expressed at a perceived deterioration in water quality of the pans making up the Oponono complex. Causes may include natural and accelerated siltation from higher up the drainage system and local impacts from trampling by cattle and fishermen. Siltation rates would need a large scale study but it was thought that the effects of trampling on water quality could be investigated more easily. During a three-day field trip most of the pans were visited and measurements of conductivity and turbidity were made. This included the effects of localised disturbance of the pan substrate and samples of ccres from the bottom of the pans.