Impacts of Vegetative Practices on Suspended Sediment from Watersheds of Arizona

Abstract

Effects of vegetative practices on suspended sediment discharge from ponderosa pine forests and pinon-juniper woodlands in north-central Arizona are examined. Sediment-rating curves were developed to analyze the impacts. Disturbance from vegetative practices generally increased suspended sediment transport above those of control (reference) watersheds. Completely cleared and strip-cut ponderosa pine watersheds produced higher sediment concentrations than did a control watershed. Likewise, cabled and herbicide-treated pinon-juniper watersheds yielded higher sediment-laden streamflows than did a control. Sediment transport regimes are also related to streamflow-generation mechanisms and hydrograph stages. Although about 85% of the data analyzed represented snowmelt-runoff events in both vegetative types, derivation of sediment-rating curves based on streamflow-generation mechanisms improved the sensitivity of the analysis. Sediment data collected during rising and falling hydrograph stages varied between th...