A Spatial Assessment of Green Infrastructure and Its Potential Effectiveness on Streamflow
Abstract
As rapid urban development with its concomitant conversion of open space and added imperviousness increases the potential for adverse hazard impacts, the possible benefits of green infrastructure as a tool for hazard mitigation has become an emerging topic in landscape architecture and urban planning. However, research on this topic has been limited by the lack of effective tools for the identification and measurement of the specific dimensions of green infrastructure and the balance between green infrastructure and urban development particularly within highly developed urban environments. Consequently, there has been little empirical research conducted on the potential benefits of green infrastructure for reducing streamflow, an indicator of runoff and potential flooding mitigation.
This study seeks to further research green infrastructure as a potential tool for hazard mitigation by examining its consequences for streamflow over a 2-year period in 2004 and 2010 for two key urban areas subject to flooding in Texas (the Austin and Houston Metropolitan areas) by 1) utilizing high resolution (1-meter) imagery to develop fine resolution assessments of the amount, form, type and placement of green infrastructure in dense urban environments and then 2) utilizing these measures in panel models to assess the effectiveness of green infrastructure for reducing runoff as assessed by using streamflow gauge data predicting annual peak flow and mean flow.
More specifically, this study first identified an approach to employ the National Agriculture Imagery Program (NAIP) and Normalized Difference Vegetation Index (NDVI) to identify and develop high-resolution measures of green infrastructure particularly germane for assessments within dense urban environments. Second, the statistical models developed utilizing these new measure of the extent and spatial patterns of green infrastructure suggested that green infrastructure indeed has consequences for streamflow reduction, particularly with respect to annual peak flow, in urban watersheds. Moreover, the analyses explained that green infrastructure in the Austin metropolitan area appears to be more effective on peak annual flow when compared to the Houston metropolitan area, suggesting that green infrastructure has elevated consequences in areas with greater topographical diversity. These variations perhaps imply that depending on different geographical characteristics, diverse guidelines for green infrastructure implementation should be applied.
The effectiveness of green infrastructure in critical places will help make a guideline for the balanced urban development with implementation of green infrastructure. This dissertation shows the utility of the new data for developing high-resolution measures of green infrastructure as a different approach compared to the conventional approaches. The consequences of green infrastructure for streamflow and potential flooding were clearly suggested. Also, this study begins to provide data that may well be used to establish guidelines for green infrastructure and effective runoff mitigation, and provides support for utilizing these data to guide research into green infrastructure spatial characteristics and hazard mitigation. Overall, the outcomes of this study will be helpful for the strategic planning and implementation of green infrastructure with streamflow issues, thus building community resilience.
Citation
Lee, Hye Kyung (2015). A Spatial Assessment of Green Infrastructure and Its Potential Effectiveness on Streamflow. Doctoral dissertation, Texas A & M University. Available electronically from https : / /hdl .handle .net /1969 .1 /156513.