William B. Hawley1,2, †, Carling C.
Hay3, Jerry X. Mitrovica4, and
Robert E. Kopp5
1Department of Earth and Planetary Science, University
of California, Berkeley, Berkeley, CA 94720, USA.
2Berkeley Seismological Laboratory, 215 McCone Hall,
University of California, Berkeley, Berkeley, CA 94720, USA.
3Department of Earth and Environmental Sciences,
Boston College, Chestnut Hill, MA 02467, USA.
4Department of Earth and Planetary Sciences, Harvard
University, 20 Oxford Street, Cambridge, MA, 02138, USA.
5Department of Earth and Planetary Sciences and
Rutgers Institute of Earth, Ocean, and Atmospheric Sciences, Rutgers
University, New Brunswick, NJ 08901, USA
Corresponding author: William Hawley (whawley@ldeo.columbia.edu)
†Now at Lamont-Doherty Earth Observatory of Columbia
University, 61 Rte. 9W, Palisades, NY 10964, USA.
Key Points:
- We present a spatially-resolved time series of sea level due to
reservoir construction from 1900 – 2040.
- Some locations in the past century have experienced a
reservoir-induced rise in sea level that exceeds 40 mm over less than
a decade.
- Future dam construction will cause patterns in sea level change that
are different from the past, and larger than current projections.
Abstract
The artificial impoundment of water behind dams causes global mean sea
level (GMSL) to fall as reservoirs fill, but also generates a local rise
in sea level due to the increased mass in the reservoir and the crustal
deformation this mass induces. To estimate spatiotemporal fluctuations
in sea level due to water impoundment, we use a historical data set that
includes 6,329 reservoirs completed between 1900 and 2011, as well as
projections of 3,565 reservoirs that are expected to be completed by
2040. The GMSL change associated with the historical data (–0.2 mm
yr-1 from 1900 – 2011) is consistent with previous
studies, but the temporal and spatial resolution allows for local
studies that were not previously possible, revealing that some locations
experience a sea level rise of as much as 40 mm over less than a decade.
Future construction of reservoirs through ~2040 is
projected to cause a GMSL fall whose rate is comparable to that of the
last century (–0.3 mm yr-1), but with a geographic
distribution that will be distinct from the last century, including a
rise in sea level in more coastal areas. The analysis of expected
construction shows that significant impoundment near coastal communities
in the coming decades could enhance the flooding risk already heightened
by global sea level rise.