Study reveals stream restoration trade-offs: Higher environmental
benefits to be had where homeowners are less willing to pay

Date:
April 26, 2022
Source:
University of Maryland
Summary:
Homeowners in Baltimore area neighborhoods where stream restoration
would do the most for water quality are far less willing to pay for
such projects, than those in other areas, according to a new study.



FULL STORY ========================================================================== Although stream restoration filters pollutants out of local waterways and improves the health of the Chesapeake Bay, Baltimore area neighborhoods
where it would do the most for water quality are far less willing to pay
for such projects, according to a new study by a University of Maryland environmental economist and an interdisciplinary team of colleagues.


==========================================================================
The team found that homeowners in the least densely populated, and
generally wealthier areas of their study region, were less willing
to pay to restore streams, while those in the most densely populated
areas, which tended to have lower incomes, were more willing to pay for restoration projects.

The study, which appeared in the journal Environmental Research Letters,
should help inform decision makers charged with improving water quality,
who often must balance community support with environmental impacts.

"We see this strong urban-to-rural gradient where in urban areas there's
a higher economic potential as far as community support to pay for stream restoration, but less ecological potential to reduce nutrient pollution,
and vice versa," said David Newburn, an associate professor in the
Department of Agricultural and Resource Economics at UMD and co-author
of the study. "The overall trend is that there's often a trade-off for environmental and economic benefits from stream restoration projects, and
it's hard to find the win-win locations." Stream restoration projects
vary greatly with the local environment, but they are all designed to
improve the ability of a stream to absorb and process nutrient pollutants
and prevent them from flowing downstream. Such projects are central
to improving water quality in the Chesapeake Bay and other watersheds
around the world. But stream restoration can change the local landscape, sometimes removing trees or adding grassy meadows along streambanks.

Newburn and his colleagues wanted to understand the complex relationship between the environmental benefits of stream restoration and the
perceived value to homeowners who frequently pay for them through
taxes and fees. The team combined their analysis of one of the most comprehensive data sets on urban stream water quality in the world with
a homeowner survey to estimate willingness to pay for various types of restoration projects.



==========================================================================
The researchers leveraged long-term sampling data from the Baltimore
Ecosystem Study, which has been measuring streamflow and nutrient load
(a measure of ecological health of a waterway) since 1998 across fully forested, agricultural and highly developed watersheds. Using modern
ecosystem modeling techniques, they estimated how much of the nitrogen
would be removed by different stream restoration designs in a variety
of settings.

They focused on small, headwater streams within the Baltimore region
spanning urban, suburban and exurban neighborhoods, meaning neighborhoods outside of city septic systems that are dominated by single family
homes on one to five acre lots. Newburn and his colleagues developed
hydrologic models that showed stream restoration had the most nitrogen reduction in the less densely populated exurban areas, where small
streams predominantly have low flows.

Streams lined by grassy buffers had the highest nutrient reduction
compared to tree-lined streams.

The researchers suggest that low water flow in these areas allowed the
streams to process nutrients in the water, and grassy buffers allowed more sunlight to reach the water than did tree covered stream banks. Sunlight
is important because it helps the algae in streams to remove nitrogen
from the water more effectively.

The projects that had the least nitrogen pollution reduction were in
the most densely populated, urban areas of Baltimore city. In these neighborhoods, urban runoff from impervious surfaces like rooftops and
parking lots leads to local flooding during rainstorms, and the torrents
of swift-moving water do not allow streams time to remove a substantial
portion of the nutrient pollution.

Next, the researchers used homeowner survey data to analyze willingness
to pay for different stream restoration designs and mapped their results throughout the study region.



==========================================================================
"In rural areas you get this high environmental benefit, that has high potential to remove nitrogen pollution from waterways, particularly when
you remove trees and have grassy streambanks to open up the streams
to sunlight," Newburn said. "But that's where you get the lowest
willingness to pay and sometimes even resistance to tree removal from
nearby homeowners compared to doing restoration somewhere else." Trees
often represent an amenity that has value because homeowners enjoy their aesthetic benefits, and removing them equates to removing this value from
the neighborhood. But in densely populated urban areas, where streams were
more likely to be surrounded by human-made infrastructure, the addition of grassy meadows or trees during restoration provides green-space amenities
that are often lacking, particularly in lower-income urban neighborhoods.

Newburn noted that the added green space in urban areas has social
benefits beyond water quality improvement that may be factored into
the environmental and socio-economic analysis for decision makers. He
also suggested that in the future, research on additional benefits of restoration projects such as reducing urban heat islands, restoring
habitats, and quality of life benefits may reveal a greater balance that
favors some projects more clearly than others.

*Andrew Rosenberg earned his Ph.D. in Agricultural Resource Economics
at UMD and is now a Research Agricultural Economist at the USDA.

This research was supported by National Science Foundation Coastal
Science, Engineering, and Education for Sustainability Program (Grant
No. 1426819), and the National Science Foundation Long-Term Ecological
Research (LTER) Program (Grant No. DEB-1027188) for the Baltimore
Ecosystem Study, and the U.S.

Department of Agriculture, Economic Research Service. This story does
not necessarily reflect the views of these organizations.


========================================================================== Story Source: Materials provided by University_of_Maryland. Original
written by Kimbra Cutlip. Note: Content may be edited for style and
length.


========================================================================== Journal Reference:
1. Ruoyu Zhang, David Newburn, Andrew Rosenberg, Laurence Lin, Peter
Groffman, Jonathan Duncan, Lawrence Band. Spatial
asynchrony in environmental and economic benefits of stream
restoration. Environmental Research Letters, 2022; 17 (5): 054004
DOI: 10.1088/1748-9326/ac61c6 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/04/220426101704.htm

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