Open-framework gravel has permeability, k, above the measurement range of most laboratory constant-head permeameters because the head difference across the length of conventional permeameters is too small to be measured. Here we addressed the challenge of measuring the high k by using a 3 m long permeameter. The head difference over this length was of the order of 10−2 to 10−3 m, which we could measure to the nearest 10−5 m. We collected data over the range of linear, laminar flow to nonlinear, laminar flow to verify that kwas measured using data collected within the Darcian regime. We measured k between 4000 and 100,000 Darcies among experiments using different sediments.