The Niobrara River flows across north central Nebraska at the northern edge of the Nebraska Sandhills. East of Valentine, the Niobrara has cut a valley 200 to 300 feet deep and between one-half to two miles wide. The Niobrara is unique in that it is the only river in Nebraska that flows directly over it's bedrock substrate. Therefore, the upper 25 miles of the Scenic River stretch tends to have more riffles and rapids making for an enjoyable, and at times exciting canoe experience. Valley side slopes are generally steeper on the south bank with vertical cliffs and over 90 waterfalls. Most waterfalls originate and are viewable along side tributaries of the south bank, such as the state's highest waterfall- Smith Falls. However, other waterfalls are visible directly from the river, such as Berry Falls and Hardin Falls. Terraces and moderate slopes are more common on the north side of the river. These are cut by steep-sided canyons of tributary streams that originate on a broad plain defining the north edge of the valley. The north slope experiences drier conditions due to more sun exposure, different soil types, and less ground water draining into the sub-strata due to the river's overall drainage pattern.