LAWRENCE, Kan. (AP) — Scientists who plan to measure the water levels in a western Kansas aquifer system this winter say they expect declines similar to those in recent years. Kansas Geological Survey researchers last year found the groundwater levels in the High Plains Aquifer had dropped an average of 3.5 feet. That's the second-largest single-year decline they had ever recorded, behind only the 4.25-foot drop measured the year prior. The Lawrence Journal-World reports that five years of drought have forced farmers to rely more on irrigation to grow their crops. But experts say such heavy usage puts a critical water resource in danger of drying up. The High Plains aquifer is a large network of underground water-bearing rocks that stretches from South Dakota to Texas.