Projected Average Summer Air Temperature Increases and the Implications for Philadelphia's Surface Drinking Water Supply
Abstract
Water managers are faced with numerous uncertainties that need to be addressed in
the development of long-term planning initiatives and large-scale investment decisions.
One of the primary and perhaps most far-reaching of these uncertainties is climate
change. The objective of this project is to utilize one aspect of projected climate
change impacts, increasing average summer air temperature, to understand potential
impacts to surface drinking water supply temperatures in the Schuylkill River at Philadelphia,
PA. The project consists of three major components. As an initial step, climate model
output from the Coupled Model Intercomparison Project Phase 5 (CMIP5) was evaluated
for the Northeast US and Philadelphia by mapping and analyzing Network Common Data
Form (NetCDF) files for near-surface air temperatures in Matlab. The evaluation of
climate model output included model validation for six selected CMIP5 Global Climate
Models (GCMs), as well as future projections using the Representative Concentration
Pathway 8.5 (RCP8.5) climate scenario. Secondly, this project aimed to develop a statistical
relationship between air and surface water temperatures in Philadelphia using publicly
available data from the United States Geological Survey (USGS) and Daymet. Following
the aforementioned empirical analyses, research was performed to provide insight regarding
the impact of increased surface water supply temperatures on the formation of disinfection
byproducts (DBPs) during drinking water treatment. The three most accurate GCMs for
the Northeast US and Philadelphia indicate that the average air temperature over June,
July, August and September (JJAS) will increase approximately 2°C by mid-century.
Assuming the RCP8.5 climate scenario prevails beyond mid-century, the results indicate
that the average JJAS near-surface air temperature may increase by as much as 5.7°C
in the Northeast US and 5.3°C in Philadelphia by 2100. For the Schuylkill River at
Philadelphia, statistical analyses reveal that air temperature explains the majority
of variation in water temperature over the time period of analysis, from 1999-2001
and 2011- 2013 for the months of JJAS. Projected increases in average JJAS air temperature
are expected to increase average JJAS surface water temperature in the Schuylkill
River at Philadelphia by approximately 1.69°C (3.05°F) and 4.23°C (7.62°F) by 2050
and 2100, respectively. Current climate science needs to be directly related to actionable
adaptation initiatives. The outcome of this study directly links one aspect of climate
change to a potential drinking water impact, with the goal of providing actionable
information to inform future operational and supply management strategies.
Type
Master's projectPermalink
https://hdl.handle.net/10161/9285Citation
Rockwell, Julia (2014). Projected Average Summer Air Temperature Increases and the Implications for Philadelphia's
Surface Drinking Water Supply. Master's project, Duke University. Retrieved from https://hdl.handle.net/10161/9285.Collections
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