Northwest Pipe Co. reported third quarter sales of $70.9 million compared with $76.0 million in the same quarter last year. Net income increased to $3.4 million for the quarter compared to $2.6 million last year. Through nine months, Northwest Pipe sales were virtually unchanged from last year at $209.5 million. Net income edged up to $8.81 million compared to $8.01 million after three quarters of 2000.