Variably saturated flow in storm-water partial exfiltration trench

Journal Article · Tue Jun 01 04:00:00 EDT 1999 · Journal of Environmental Engineering

DOI:https://doi.org/10.1061/(ASCE)0733-9372(1999)125:6(556)· OSTI ID:354310

Li, Y; Buchberger, S G ^[1]; Sansalone, J J ^[2]

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1. Univ. of Cincinnati, OH (United States). Dept. of Civil and Environmental Engineering
2. Louisiana State Univ., Baton Rouge, LA (United States). Dept. of Civil and Environmental Engineering

Storm water from impervious urban areas can adversely impact water quality and quantity. The partial exfiltration trench (PET) is a control device designed to moderate both the quality and the quantity of urban runoff. This paper uses a 2D numerical model to evaluate variably saturated flow profiles and residence time distributions for a PET subject to storm water loading. Parameters estimated from laboratory experiments show that flow through the PET is influenced strongly by the rate and duration of the hydraulic loading and by the type and properties of the surrounding soil. Unless the surrounding soil is nearly saturated or highly impermeable, propagation of the wetting front through an unlined PET occurs as 2D variably saturated flow. Variably saturated 2D flow through the PET is characterized by skewed residence time distributions, long mean travel times (relative to plug flow), high exfiltration losses to the surrounding soil, and low tracer mass recovery at the underdrain. These features of the PET performance are beneficial for storm-water treatment because the first flush of runoff often contains significantly higher pollutant concentrations than those present in later phases of the storm.

• OSTI ID: 354310
• Journal Information: Journal of Environmental Engineering, Journal Name: Journal of Environmental Engineering Journal Issue: 6 Vol. 125; ISSN 0733-9372; ISSN JOEEDU
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
FLUID FLOW
MATHEMATICAL MODELS
PERFORMANCE
POLLUTION CONTROL EQUIPMENT
RUNOFF
STORMS
SURFACE WATERS
URBAN AREAS
WATER POLLUTION
WATER POLLUTION CONTROL