Cumulative Effects of Low Impact Development on Watershed Hydrology in a Mixed Land-Cover System

Abstract

Low Impact Development (LID) is an alternative to conventional urban stormwater management practices, which aims at mitigating the impacts of urbanization on water quantity and quality. Plot and local scale studies provide evidence of LID effectiveness; however, little is known about the overall watershed scale influence of LID practices. This is particularly true in watersheds with a land cover that is more diverse than that of urban or suburban classifications alone. We address this watershed-scale gap by assessing the effects of three common LID practices (rain gardens, permeable pavement, and riparian buffers) on the hydrology of a 0.94 km 2 mixed land cover watershed. We used a spatially-explicit ecohydrological model, called Visualizing Ecosystems for Land Management Assessments (VELMA), to compare changes in watershed hydrologic responses before and after the implementation of LID practices. For the LID scenarios, we examined different spatial configurations, using 25%, 50%, 75% and 100% implementation extents, to convert sidewalks into rain gardens, and parking lots and driveways into permeable pavement. We further applied 20 m and 40 m riparian buffers along streams that were adjacent to agricultural land cover. The results showed overall increases in shallow subsurface runoff and infiltration, as well as evapotranspiration, and decreases in peak flows and surface runoff across all types and configurations of LID. Among individual LID practices, rain gardens had the greatest influence on each component of the overall watershed water balance. As anticipated, the combination of LID practices at the highest implementation level resulted in the most substantial changes to the overall watershed hydrology. It is notable that all hydrological changes from the LID implementation, ranging from 0.01 to 0.06 km 2 across the study watershed, were modest, which suggests a potentially limited efficacy of LID practices in mixed land cover watersheds.

Development of a Multi-Scale Stormwater Management Modelling Methodology

“…The authors have classified the BMPs, on the functions, as infiltration-based and retention-based. Many other microscale studies have shown an excellent performance of LIDs (Ahiablame et al 2012;DeBusk and Wynn 2011;Dreelin et al 2006;Hoghooghi et al 2018;Hunt et al 2008;Li et al 2017;Palla et al 2008;Salvadore et al 2015;Di Vittorio and Ahiablame 2015;Xiao et al 2006), some studies have mentioned that rather than individual LID the combination of LIDs perform better (Joksimovic and Alam 2014;Palla et al 2008). However, a generalization of the results of LID from those studies is difficult because of the variability of the performance of the various LIDs (Ahiablame et al 2012).…”

Integrated water management recommendations in practice: coexistence of old and new ways in Arizona

“…Apart from water demands, the characteristics of the built environment also co-determine flood risk. Installation of low impact development practices, such as rain gardens, permeable pavement, and riparian buffers, decrease surface runoff and peak flows (Korgaonkar et al, 2018;Hoghooghi et al, 2018).…”

An Integrated Multi-Model Decision Support Framework for Evaluating Ecosystem-Based Management Options for Coupled Human-Natural Systems

“…VELMA is applicable to essentially any terrestrial ecosystem (urban, agricultural, forest, grassland, prairie, wetland, etc. ), as well as to mixed-use watersheds and regional basins (Abdelnour et al 2011(Abdelnour et al , 2013McKane et al 2014a, b;Hoghooghi et al 2018;McKane et al 2018a, b, c).…”