Efficacy of Sediment Basins for Reducing Sediment and Pyrethroid Transport in Almond Orchards

摘要

This study examined the effectiveness of sediment basins for reducing sediment and pyrethroid residues in tailwater in two different trials conducted on a section of a large-scale commercial orchard in the Central Valley of California planted with nonpareil almonds. The first trial was conducted under typical tailwater flow conditions with no PAM added to the irrigation water. The second trial was conducted under slightly higher flow rates with PAM added at the point of irrigation input resulting in a five-fold reduction in total suspended solids (TSS) entering the sediment basin. In both trials, the total mass of the sediment leaving the sediment basin was reduced 79%-84% at the discharge point of the basin. Although PAM did not appear to significantly impact the total mass of pyrethroid leaving the field in this study, the sediment basin reduced the total pyrethroid load by 38%-61%.