Urban Stream Deserts as a Consequence of Excess Stream Burial in Urban Watersheds

Abstract

The Rouge River watershed, a highly urbanized watershed in southeast Michigan, has substantial impervious surface coverage, relatively high population density, and modified stream network (e.g., stream straightening and burial, dams, and underground retention). The number of stream channels and order decreases, increasing flooding, reducing water quality, and decreasing aquatic species. This study defines, identifies, and describes the progression of the geographic pattern of urban stream deserts—defined as those areas within a watershed that exhibit no surface stream channels due to the effects of human development and population growth. Urban stream deserts are identified and characterized using three data sets: (1) historical aerial imagery, (2) historical census boundary and tables, and (3) stream network data. Flowlines digitized off aerial photos from 1949 are compared against 2013 flowlines to identify areas of the watershed now devoid of stream channels. In the Rouge River watershed, stream density has decreased since 1949, which coincides with a rapid population increase and systematic burial of urban streams. Urban stream deserts in the Rouge River watershed constitute 23 percent of the watershed area, but these areas included as much as 66 percent of the watershed population in 1950 (as the urban stream deserts were developing) and dropped to 41 percent in 2010. This conceptual model of urban stream deserts is applicable to many urban and industrialized areas that have replaced stream channels with infrastructure during periods of economic growth, only to experience depopulation, aging infrastructure, and, as a result, degraded, modified, or altogether buried stream networks.