HIGH-VOLUME RAINFALL IMPACTS AND ADAPTATION IN THE U.S. MID-ATLANTIC UNDER CLIMATE CHANGE AND URBANIZATION

Abstract

Water over-abundance has negative effects on proper functioning of ecosystem services. The increase in heavy precipitation events and hence stormwater quantity, due to climate change and urbanization, is a major flooding concern. These events also affect ecosystem processes leading to soil erosion and sedimentation. This dissertation draws from different disciplines and involves quantification of hydrological extremes, assessment of stormwater management resilience and analysis of impacts on ecosystem services under anticipated future changes in the U.S. Mid-Atlantic region.

In Chapter 2 of the dissertation, use of precipitation capture depth and findings of likely increase in heavy precipitation events is relevant to flooding concerns at small watershed scales (~3 km2) and are valuable planning-level information for municipal stormwater management. Estimates developed in this dissertation of changes in water volume and resultant on-site infrastructure costs can help stakeholders and managers in planning for flood mitigation and protection of ecosystem services. In addition, the use of capture depth percentiles such as d85, d90, d95, and d99, have the potential to serve as meaningful hydrologic indicators for stormwater management planning. In Chapter 3, the finding of likely higher erosion rates and sediment yield in the future is a point of concern and relevant for effective land use planning. The approach to estimate representative calibration values for sediment delivery ratio model, at small scale (~3 km2) urban watersheds, is valuable for ungauged sites replacing average or theoretical calibration values. In Chapter 4, the construction of a simple curve number watershed model with reasonably good performance and few input data needs offers a possible flow simulation tool for medium to highly impervious watersheds at small scales. Moreover, the stormwater management pathways along with cost-benefit assessment using green stormwater management practices serve as a first step to determine effectiveness of certain green practices at the watershed scale. It provides insights and help identify future research needs to fill gaps in our understanding of green stormwater management practices and how they affect ecosystem services.