Land use change and hydrological impacts on historical and present-day channel and floodplain form, Blue River watershed near Kansas City, Missouri

Keywords: Fluvial Geomorphology
Abstract Type: Paper Abstract

Abstract

Channel form can respond to changes in flood regime and sediment load caused by land use and climate disturbances. If conditions are severe enough, hydrological connections between the channel and its floodplain can be altered leading to geomorphic adjustments across the valley floor. Investigating the historical evolution of a stream channel system including its floodplains can help to advance geomorphological theory and benefit environmental managers. This study documents the influence of human impacts on historical changes in channel and floodplain widths since the early to middle 1800s in the Blue River in Kansas City, Missouri. The Blue River watershed is situated in the transitional area between the Ozark Plateaus in Missouri and Central Lowlands in Kansas. It has been affected by a long agricultural history as well as more recent but significant urban-industrial growth. Historical channel changes will be assessed by: (i) General Land Office (GLO) surveys from 1826 that describe pre-settlement channel conditions; (ii) Bank-line changes over time using aerial photography since the 1950s; and (iii) Locations, dates, and types of bank stabilization structures and channel modifications. Channel data combined with census data, flood records, land use trends, and GLO surveyor notes indicated significant changes in channel width and location of Blue River. In general, there was a geomorphic shift from a wide, shallow, multi-threaded system to a narrower, deeper, single-channel stream. In addition, bank height and floodplain area has increased inferring that legacy floodplain deposits occur along most the present-day channel.