No 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.

County‐level, Order 2 soil surveys have been used for decades to illustrate the spatial distribution of soils and communicate the utility and limitations of soil series. For the vast majority of these soil surveys, however, there is a distinct lack of resolution of soil series and associated data for urban or highly developed areas of the United States. Yet, with unprecedented vacancy and demolitions in major U.S. cities, the availability of large tracts of open and relatively inexpensive urban land suggests that there are many prospects for using these soils for something other than redevelopment. Therefore, current public interests center on how urban soils may be used to provide a myriad of ecosystem services. Due to the different emphasis, data needs are different than for past soil surveys and we therefore suggest an approach and protocol that was employed in Cleveland, OH in 2010. This work is centered on the possibility of using vacant land mass to infiltrate and otherwise absorb excess stormwater runoff quantity as a sustainable and putatively cost‐effective way of managing combined sewer overflows (CSO). We examined a sample set of 56 vacant lots and 14 city parks or cemeteries located in the drainage areas of relatively small‐volume, high frequency CSOs. This paper details the survey approach rationale, methods, and level of effort required and presents a case study. Overall, this work is submitted as a proposal to the soil survey community for a soil survey protocol aimed at servicing emergent environmental management data needs in urban core areas of the United States.

No abstract

The fragipan subsoil horizon can be a significant limitation to land use and management because of its ability to perch water, restrict root growth, and reduce available water storage. Recognition of the presence of a fragipan is used to describe some diagnostic horizons (mollic, umbric, cambic) and to identify the limits of the particle size control section when classifying a soil according to the U.S. soil taxonomic system. While soil scientists often disagree on whether fragipan diagnostic criteria are met, they will typically agree that the horizon has fragic soil properties. To potentially improve field identification agreement, we propose that the fragipan be redefined to meet criteria more like fragic soil properties. We also propose to include some current criteria for the fragipan denoting pedogenesis, slaking, and HCl reaction. In addition, we propose a new requirement be added for redoximorphic features above the fragipan as additional evidence of its restrictive nature. Changing the fragipan's definition will do little to alter soil land use interpretations given most interpretations are based indirectly off the effects of the fragipan. Analysis of existing series indicates that our proposal should not remove series now classified with a fragipan but would eliminate some ambiguities in field identification. Whether the fragipan's spatial extent would increase or decrease is dependent on regional mapping efforts.