Effect of fire on water quality in an Arizona ponderosa pine forest

The primary objective of this study was to investigate and compare the effects of a controlled burn on water quality against the effects measured in a previous study on a wildfire. A secondary objective was to develop a set of empirical equations to predict water quality changes following fire. Fluoride, calcium, magnesium and pH in the water were found to increase and the sodium absorption ratio to decrease following the controlled burn. Concentrations of calcium, magnesium, sodium, nitrate, as well as the sodium adsorption ratio, following the wildfire were significantly different, to allow the water to be considered of lesser quality. Prediction equations were developed from the controlled burn data for the pH, sodium and the sodium adsorption ratio. However, these equations are not considered accurate predictors and should be used only as indications of possible trends.