You are here:
Cumulative Effects of Low Impact Development on Watershed Hydrology in a Mixed Land-Cover System
Citation:
Hoghooghi, N., H. Golden, B. Bledsoe, B. Barnhart, A. Brookes, K. Djang, J. Halama, Bob Mckane, C. Nietch, AND P. Pettus. Cumulative Effects of Low Impact Development on Watershed Hydrology in a Mixed Land-Cover System. WATER. MDPI, Basel, Switzerland, 10(8):991, (2018). https://doi.org/10.3390/w10080991
Impact/Purpose:
We provide one of the first studies, to our knowledge, that assesses the relative watershed-scale hydrological effects of different types and configurations of LID practices in a mixed land cover watershed using a spatially explicit modeling approach. We simulated 10 scenarios across multiple spatial configurations of LID to evaluate the watershed hydrological responses of three practices—rain gardens (RG), permeable pavements (PP), and riparian buffers (RB)—in a 0.92 km2 watershed with mixed suburban, agricultural, and forest land cover. A spatially-explicit ecohydrological model (VELMA) was used to compare changes in the watershed’s water balance before and after LID practice implementation.
Description:
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 km2 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 km2 across the study watershed, were modest, which suggests a potentially limited efficacy of LID practices in mixed land cover watersheds.
URLs/Downloads:
DOI: Cumulative Effects of Low Impact Development on Watershed Hydrology in a Mixed Land-Cover System
https://doi.org/10.3390/w10080991