Abstract |
A study of return flows in the Wapato Irrigation District in the Yakima River Basin in central Washington was made during the 1963 irrigation season to determine effects of the (principally) irrigation use on water quality. Parameters investigated included temperature, oxygen demand, hardness, turbidity, coliform bacteria, pesticide toxins, and various nutrient ions. Some degradation of quality was observed for nearly every parameter, but the overall effect was not severe. The chief recommendations for improvement of water quality involve improvements in amount and timing and method of application of the irrigation water, and a continuing educational safety campaign on use of pesticides. (Author) |