Sediment accumulation expectations for growing desert cities: a realistic desired outcome to be used in constructing appropriately sized sediment storage of flood control structures

Abstract

Many rapidly urbanizing desert cities (RUDC) around the globe experience an acute risk of flooding. To reduce this risk, properly engineered flood control structures (FCS) must account for sediment accumulation as well as flood waters. While the Phoenix area, USA, uses regional data from nonurban, non-desert watersheds to generate sediment yield rates, the proposed desired outcome for RUDCs is to base FCS on data related to urbanization. Wolman (1967 Geogr. Ann. A 49 385-95) recognized that sediment yields spike during a relatively short period of bare-ground exposure associated with urban growth, followed by surface sealing resulting in a great reduction in sediment yield. This research presents a new analysis of empirical data where two regression models provide estimates of a more realistic sediment accumulation for arid regions and also urbanization of a desert cities: (i) linear regression between drainage area and sediment yield based on a compilation of more than 150 global sediment yield data for warm desert (BWh Köppen-Geiger) climate; and (ii) linear regression relating percent urban growth with sediment yield using available data on urbanizationgenerated sediment associated with growth of a desert city. The new model can be used to predict the realistic sediment accumulation for helping provide data where few data exists in urbanizing parts of arid Africa, southwest Asia, and India.

Implications of a specific storm event for understanding adjustment of urban dryland channels

“…A growing body of literature has suggested the effectiveness of management in mitigating and even reversing the deleterious impacts of urbanization. These practices include water infrastructure to counteract increased imperviousness (Bhaskar et al, 2020;Oudin et al, 2018) and store sediment (Jeong, 2019), as was demonstrated in central Arizona where retention basins decreased stream flashiness (McPhillips et al, 2019). Fountain Hills, therefore, may give a template for proactive management and geomorphic design (Chin & Gregory, 2009;Gregory & Chin, 2018) in guiding urbanizing dryland river systems towards stability.…”

Acceleration of Soil Erosion by Different Land Uses in Arid Lands above 10Be Natural Background Rates: Case Study in the Sonoran Desert, USA

“…The 18 stock pond watersheds (Figures 2 and 3) are located on pediments and fans with a variety of rock types (Figure 3). Urban sprawl in the Sonoran Desert (Figure 2) increased the region's vulnerability to erosion through construction, exposing bare ground to rainfall and runoff [32,55].…”

“…The stakes associated with urbanization-enhanced soil erosion tend to be spatially variable, as is the case for all soil erosion [19,31,109]. For example, the effects of urban soil erosion in the Phoenix area are relatively minor-impacting such issues as reservoirs [55], water quality [110], and health effects from heavy metals [111]. In other cities, soil erosion can impact the urban poor in a variety of ways, including a negative health impact [112] and water quality [113].…”