Channel incision began after 1880 in Douglas Creek, a tributary of the White River in northwestern Colorado. This modern erosion produced a complex series of discontinuous, unpaired terraces below the 1880 valley floor. As many as four of these surfaces were formed below the level of the old valley floor by a process of discontinuous downcutting that apparently was not related to changes of base level, climate, or land use, although the initial incision was probably due to the introduction of large numbers of livestock.
The progress of incision was impeded as large quantities of sediment were flushed from steep tributary valleys into the main channel. Temporary storage and flushing of the sediment by episodic erosion produced a complex post-1900 terrace sequence. This phenomenon may be expected following rejuvenation of areas of high relief and high sediment production, and episodic incision may be a normal part of the erosional evolution of such areas.