Exhibit 99.1 Northwest Pipe Company Announces First Quarter 2024 Financial Results • Net sales of 113.2millionincreased14.220.1 million increased 21.5% year-over-year, the highest first quarter gross profit in 11 years • Net income of 0.52perdilutedshare•Backlog1of255 million; backlog including confirmed orders2 of 337millionfortheEngineeredSteelPressurePipesegment(“SPP”)•Orderbook3of52 million for the Prec ...