Bioretention Design for Xeric Climates Based on Ecological Principles¹

Abstract

Bioretention as sustainable urban stormwater management has gathered much recent attention, and implementation is expanding in mesic locations that receive more than 1,000 mm of annual precipitation. The arid southwestern United States is the fastest growing and most urbanized region in the country. Consequently, there is a need to establish design recommendations for bioretention to control stormwater from expanding urban development in this ecologically sensitive region. Therefore, we review the ecological limits and opportunities for designing bioretention in arid and semiarid regions. We incorporated USEPA Stormwater Management Model (SWMM) simulations to synthesize ecologically based design recommendations for bioretention in arid climates. From our review, an ideal bioretention garden area should be 6 to 8% of the contributing impervious drainage area (depending on region) with two layers of media, a 0.5‐m low‐nutrient topsoil layer above a 0.6‐m porous media layer that acts as temporary storage during a storm event. When planted with the suggested vegetation, this design maximizes stormwater treatment by promoting ecological treatment in the topsoil while promoting infiltration and evapotranspiration of stormwater by deep‐rooted shrubs that require no irrigation after establishment. This synthesis improves water resources management in arid and semiarid regions by introducing a sustainable bioretention design that protects local surface waters while reducing regional water demands for irrigation.

Evaluation of three vegetation treatments in bioretention gardens in a semi-arid climate

“…Bureau of Reclamation, 2007) and therefore, does not meet LID objectives. Houdeshel et al, 2012). The control cell and upland cell included the infiltration bay shown in the image, however, the Wetland Cell did not.…”

“…These guidelines include: (1) the use of regionally native upland vegetation adapted to water-limited climates instead of wetland vegetation that has substantially higher water demands, and (2) routing stormwater to a sub-grade gravel storage layer instead of allowing stormwater to pond on the surface of bioretention facilities. Houdeshel et al (2012) demonstrated the hydrological performance of their suggested design, but the nutrient treatment performance of using upland vegetation in bioretention in concert with a sub-grade storage reservoir has not been tested.…”

“…We compared the treatment capacity of the bioretention design recommended by Houdeshel et al (2012) against a wetland vegetation community suggested for use in bioretention in more mesic climates and against a media-only system without vegetation (i.e. bare soil).…”

“…Flow from the 1" sample collection pipe was controlled to replicate the water level drop from the expanded shale reservoir as measured in an adjacent cell of similar design without an impervious liner (Steffen, 2012). Houdeshel, Pomeroy, and Hultine (2012) proposed design guidelines for bioretention stormwater treatment facilities in water-limited climates based on biogeochemical processes such as evapotranspiration (ET) and nutrient cycling in water-limited ecosystems. These guidelines include: (1) the use of regionally native upland vegetation adapted to water-limited climates instead of wetland vegetation that has substantially higher water demands, and (2) routing stormwater to a sub-grade gravel storage layer instead of allowing stormwater to pond on the surface of bioretention facilities.…”

Hydrological Design of Two Low-Impact Development Techniques in a Semi-Arid Climate Zone of Central Mexico

“…The wetted perimeter (W p ) and hydraulic radius (r) were calculated applying Equations (15) and (16).…”