Ecological engineering in a new town development: Drainage design in The Woodlands, Texas

Abstract

a b s t r a c tThis paper presents a comparative study of two different drainage designs in a 10,930-ha new town development of The Woodlands, Texas. Open surface drainage by shallow grassed swales was used in the first two subdivisions that were developed with ecological approaches. Open surface drainage mimics the natural flow regime and is regarded to mitigate development impacts on watershed. In other later subdivisions, the drainage design shifted back to a conventional stormwater drainage system, that is, curb and gutter, drop inlet, and underground piping, known to concentrate stormwater and lead to downstream flooding. The objective of this study is to compare The Woodlands' two drainage systems on their correlation with downstream floods. Two sub-watersheds within The Woodlands that used different drainage designs were compared. U.S. Geological Survey stream data from the gauge station at the outlet of each sub-watershed were used for analysis. Geographic Information System was used to quantify the development conditions. Correlation analysis was performed using measured precipitation and streamflow data.Results show that open drainage watershed generated less storm runoff than the conventional drainage watershed, given the similar impervious area in both watersheds. Furthermore, the open surface drainage watershed responded to rainfall in a way similar to its predevelopment natural forest conditions, indicating effective flood mitigation post development. In contrast, in the conventional drainage watershed, the precipitation-streamflow correlations increased enormously after development. The open drainage system presents an advantage over the conventional drainage one in mitigating flood problems in urban development.Published by Elsevier B.V.

Green Infrastructure Design for Stormwater Runoff and Water Quality: Empirical Evidence from Large Watershed-Scale Community Developments

“…Moreover, this study confirms with previous studies that integrated GI design strategies are better than a single strategy [30,31,44]. This is because Site 1's GI design mimics the natural hydrological cycle by keeping the portion of runoff that originally infiltrates underground.…”

“…At the regional scale, lands with large patches of sandy soils were preserved as open space to infiltrate runoff [45]. Road alignment considered sandy soil locations where check dams were built to slow runoff velocity (see Figure 3) [31,50]. At the site level, a Landscape Clearance Index was developed to ensure the minimum clearance of vegetation.…”

“…It is a precursor of the USEPA's GI design initiative: a series of integrated GI design strategies were used to meet flood control and stormwater quality goals [44][45][46][47]. Several recent studies have demonstrated the effectiveness of The Woodlands GI design on flood mitigation [31,32,46]. In addition to stormwater quantity, this current study further assessed water quality performance of The Woodlands' GI design with built communities that use the conventional drainage design.…”

“…GI design typically encompasses open space, parks, green roofs, bioretention and constructed wetlands, decentralized water management (e.g., rainwater harvesting), protection of riparian areas, and various hybrids of pervious surfacing options [26,27]. GI design is based on ecological engineering principles [28,29], and a number of studies have suggested that integrated GI designs can be more effective than single-design strategies [30][31][32]. While the main focus of conventional drainage solution is peak discharge reduction, GI design aims at restoring the predevelopment flow regimes, such as reduction of runoff volume, enhancement of stormwater quality, and maintenance of base flows [33][34][35].…”

An evaluation of the Stormwater Footprint Calculator and the Hydrological Footprint Residence for communicating about sustainability in stormwater management

“…These techniques are controversial and may require new initiatives by utilities and local governments because they deviate from the conventional approach to stormwater management, which uses an end-of-pipe centralized design (Coffman et al 1999;USEPA, 2000). Although some site-specific LID projects have been successfully implemented and monitored in the United States, for example in Philadelphia (Landers, 2009), Chicago (Dreher, 2009), and the Woodlands (near Houston) (Yang & Li, 2010), lot-level LID technologies have not gained widespread adoption in the United States or abroad (Roy et al 2008;Ahiablame et al 2012).…”