“We are all born with a unique genetic blueprint,
which lays out the basic characteristics of our personality as well as our physical
health and appearance...And yet, we all know that life experiences do change
us.”
- Joan D. Vinge
Purpose. Many aspects of life are centered upon a
sense of purpose, upon the “why?” factor that either motivates us or moves us
to find another use for our time. Fortunately, this summer was devoid of the
latter and saturated with the former. The beginning of these past eight weeks
was nothing short of a search for purpose as I tried to find my footing within
the larger scope of the program. Thanks to the guidance and support of my
faculty mentor Zach Raff, that purpose was found in short order as we promptly
set our research project in motion. While I was excited to begin and well aware
of how rewarding the process would be, I quickly realized that this summer was
going to be a lot more than an exercise in research exposure; the experience as
a whole would shape my career goals and personal outlook on what it means to
find one’s niche in the world.
From a formative beginning to a resoundingly
successful end, with all the data fanfare in between, our research project was
the driving force behind this summer’s adventures. For our project, Zach and I
chose to analyze the Minnesota Phosphorus Lawn Fertilizer Law’s effects on
water quality. Essentially, we set out to empirically determine if the
statewide Law had actually produced its intended effect of reducing phosphorus
content in surface waters e.g. lakes, rivers, streams. Doing so would allow us
to conclude whether or not a policy of the Minnesota Law’s caliber should be
implemented in the state of Wisconsin so as to replicate any potential
reductions in phosphorus content; the Wisconsin state legislature actually
enacted a similar statewide water quality policy (2009 Wisconsin Act 9) in 2010,
but when it comes to overall extensiveness, it pales in comparison to the
stringency of the Minnesota Phosphorus Lawn Fertilizer Law.
Being that the Law centers on suburban and urban phosphorus runoff abatement, we pulled
phosphorus content data from the National Water Information System (NWIS) and
the EPA’s Storage and Retrieval System (STORET) for all counties in Minnesota
and Wisconsin. Our analysis of the phosphorus content data utilized a fixed
effects regression model with a difference-in-differences estimator tossed in
to account for the treatment “group” Minnesota and the control “group”
Wisconsin; Minnesota receives a treatment in the form of the Phosphorus Lawn
Fertilizer Law while Wisconsin does not, thus forming the basis of a classic
natural experiment. Fixed effects allow us to control for time-invariant
variables (things that don’t change over time) such as geographical incongruity
as well as entity-invariant variables (things that may change over time but not
between entities) such as national level legislation; our model uses location
(e.g. county, watershed) as its entity variable and months as its time
variable. Finally, our difference-in-differences approach enables the modeling
of water quality differences between
Minnesota and Wisconsin over time to ascertain the Phosphorus Lawn Fertilizer
Law’s impact.
The econometric modeling we ran included two control
variables for the sake of producing the most robust result possible: population
density and mean precipitation by county. Three models were created in total,
each with increased inclusion of fixed effects and control variables. The third
and most complete model, including all fixed effects and control variables, was
ultimately became our flagship result. Based on its econometric analysis, we
were able to conclude that the Minnesota Phosphorus Lawn Fertilizer Law was
significantly and directly responsible for reducing phosphorus content by 0.096 mg/l. We were able to accomplish
what previous similar studies were not, which is finding a clear causal relationship between improved water quality and policy.
Applying this reduction in phosphorus content
specifically to Dunn County and the average phosphorus content of its surface
waters, we estimate a decrease in average phosphorus from 0.663 mg/l to 0.567
mg/l. Despite not reducing phosphorus content to healthy levels outright,
augmenting the Wisconsin fertilizer law to be as stringent and extensive as
Minnesota’s does have a much prettier associated monetary benefit: the 0.096
mg/l reduction in phosphorus content would result in a property value increase
of $3,174 per lakefront or
near-lakefront property in Dunn County.
Implementing a policy like the Minnesota Phosphorus
Lawn Fertilizer Law appears to be relatively
costless, which serves to add more fuel to the fire that is the process of motivating
Wisconsin state legislators to improve the existing Wisconsin fertilizer law to
be on par with Minnesota’s. That being said, our goal now is to fine tune our
research so that we may effectively present this information to Wisconsin
policymakers with the aim of bringing real change to fruition and developing another
angle of attack in the battle against phosphorus runoff.
While real
policy change is still on the horizon, another type of change has already taken
effect. This change, however, is one within myself as a person and as an
academic. Coming into this REU, I knew I wanted to attend graduate school but I
had no idea what kind of research I would choose to engage in. Being exposed to
environmental policy and economics, as well as taking in the perspectives of my
LAKES colleagues, has led me to become a more well-rounded academic with new
aspirations to make meaningful impacts through research. As I sit in front of
my laptop with the last days of LAKES looming, I know now that this is the sort
of work that I want to dedicate my knowledge and efforts to.
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