“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.