Hydropedological Assessments of Parcel-Level Infiltration in an Arid Urban Ecosystem

Abstract

soil morphology and correspondent hydrologic data can contribute to qualifying and quantifying urban soil suitability and capacity to cycle stormwater runoff. We put particular emphasis on the possibility that residential parcels may manage their own stormwater on pervious yard areas. We assessed the morphology of Aridisol pedons (as deep cores to approximately the 3.6-m depth) via soil taxonomy, performed in situ measurements of infiltration, and measured subsoil hydraulic conductivity in two desert parks, four residential parcels, and three dual-purpose park-stormwater retention basins in the Phoenix, AZ, metropolitan area. Infiltration rates overall ranged between 0.4 and 1.7 cm h −1 . We used borehole hydraulic conductivity as a proxy for drainage, which ranged from a low of 0.0 to 13 cm h −1 . Representing a baseline, or set of "natural" hydrologic processes, native desert sites exhibited a relatively high capacity to infiltrate and redistribute rainfall, which, depending on storm intensity, may drain to washes or ephemeral streambeds via subsurface runoff. simulations of stormwater runoff on residential parcels showed that when rooftop runoff is directed to pervious patches, rainfall is entirely infiltrated and redistributed, which predicts good potential for parcel-level stormwater management. Our observation of an accumulation of fine sediments in retention basin surface soils was corroborated with local observations that drawdown times in the retention basins had increased with time. Although further assessment is needed on a wider variety of semiarid landscapes, our results suggest a positive role for residential parcels in detaining stormwater on site and perhaps easing the wet-weather burden on centralized stormwater infrastructure in semiarid urban ecosystems.

Comparison of Measured and Simulated Urban Soil Hydrologic Properties

“…Urban soils undergo processes that vastly alter hydrology at the anthropogenic time scale, e.g., a demolition that alters soil conditions in under 1 week. Similarly, the variation in urban soil hydrology at the spatial scale can vary at the submeter scale (Shuster et al 2014(Shuster et al , 2015, making even the highly interpolated mapping efforts of SSURGO inadequate. This begs the question: are tools like USDA Rosetta or soil hydrologic data obtained from either the NSWC or SSURGO adequate for modeling hydrologic responses of urban systems?…”

Urban vacant lands impart hydrological benefits across city landscapes

“…Though we focus on the partitioning of rainfall between infiltration and surface runoff, detention capacity may be indirectly altered through deep drainage and evapotranspiration 25,51 . As vegetation intercepts rainfall that would otherwise reach impervious areas 21 , the presence of vegetation on vacant parcels may amplify the RDT of these areas.…”

“…The urban subsurface will also shape the efficacy of vacant parcels to serve as stormwater resources 17,40,51 . However, the impact of subsurface characteristics and below-ground hydrologic processes (e.g., deep drainage) on detention capacity represents a major source of uncertainty because subsurface hydrologic data are limited in most urban areas ( Supplementary Note 2).…”

Full Water‐Cycle Monitoring in an Urban Catchment Reveals Unexpected Water Transfers (Detroit MI, USA)

“…We measured both infiltration and drainage rate of soils in permeable areas of the study area as described in Shuster et al () and reported in Hoard et al (). Infiltration rate was measured at 6‐m intervals along two parallel 55‐m transects of permeable, fallowed areas with tension infiltrometers set to approximately 2 cm of suction head.…”