Date of Award

5-2015

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Civil Engineering

Committee Member

Dr. Nigel B. Kaye

Committee Member

Dr. William D. Martin III

Committee Member

Dr. Ashkok K. Mishra

Abstract

A warming climate leads to a moister atmosphere and more rapid hydrologic cycle. As such, many parts of the country are predicted to experience more total rainfall per year and more frequent extreme rainfall events. Most regions of the country have stormwater systems designed to a standard that matches outflow to pre-development values for specified return period storms. Increases in these return period storm depths, as predicted by many global climate models, will stress existing stormwater infrastructure. This thesis examines two issues related to the impact of climate change on stormwater management in the state of South Carolina, namely how will rainfall patterns change over the remainder of the century and how can our approach to stormwater management system design adapt to these changing conditions. Rainfall simulations from 134 realizations of 21 global climate models were analyzed across the state of South Carolina through 2099. Results show that there will be increases in both annual total rainfall (ATR) and 24 hour design storm depth for a range of return period storms. Across South Carolina, ATR is predicted to increase by approximately 1.5-3.3 inches over the forecast period while the 100 year design storm depth is predicted to increase by 0.5-1.2 inches depending on location. However there are significant regional variations with the Savannah River Basin experiencing smaller increases in ATR compared to the rest of the state. The impact of these changes in rainfall patterns on the outflow characteristics of various land developments was examined through a series of case studies. Hydrologic models were developed for three different development sizes at three locations in the state to evaluate the effectiveness of Low Impact Development (LID) technologies in site design. LID usage increases in onsite retention and disposal which significantly reduces total runoff and can also reduce peak runoff rate. Depending on the location-specific infiltration, developments with LID usage can reduce runoff volume to below predevelopment values and significantly reduce peak outflow. The use of LID can also reduce the required pond size by up to 70% allowing for more space for land development or water quality control structures.

Share

COinS