The Relationship Between Land Use And Phosphorus LoadingA Sampling of Forested and Agricultural Land Use Basins Within The Lamoille Valley

Alan Therrien and Jay Modry, Hazen Union School

HypothesisIf we test the phosphorus levels of the river at different sites with different land uses

then we will find that the phosphorus will be more abundant at the sites where there is

more agriculture and less forest in the drainage basins. We predict this because there

is phosphorus found in many things that are found in agricultural areas such as

fertilizer and manure. These types of things are not found in forested areas so the

phosphorus levels at the sites with the heavily forested drainage basins should be

much lower.

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Watershed Classification

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Watershed Classification

Site 1

Watershed Class 1 "Forested"

% Forested

% Ag

% Urban

%Other

Site 2

Watershed Class 1 "Forested"

% Forested

% Ag

% Urban

%Other

Site 3

Watershed Class 2 "Forest/Ag"

% Forested

% Ag

% Urban

%Other

Site 4

Watershed Class 2 "Forest/Ag"

% Forested

% Ag

% Urban

%Other

Site 5

Watershed Class 3 "Agriculture"

% Forested

% Ag

% Urban

%Other

Site 6

Watershed Class 3 "Agriculture"

% Forested

% Ag

% Urban

%Other

Upper Lamoille In Forested Area

Phosphate Being Applied On Agricultural LandManure on Agricultural Field Above Tributary

Methods To test our hypothesis we needed to take water samples from our designated sites, and

use the data that was collected by other schools at the other sites. We collected the

samples by using the designated Total Phosphorus bottles that were sent to us by the

EPSCOR project along with the other containers we were using to collect samples such

as Total Suspended Solids and Bacteria. We collected this data about twice a month

from the end of summer and into the fall until the river became too dangerous to collect

samples. After the samples were collected they were sent back to the lab where they

were tested and the results were then posted online. This is how we were able to use

data from not only our site, but those of others who were participating in the project.

In order to answer our question we needed drainage basins along the Lamoille River

that had different percentages of forested and agricultural land. This is where we used

the GIS software to produce a map with six different basins that could be separated into

three different classes, depending on their percent of forested area. Within each of

these three different classes we chose two different sites to calculate the phosphorus

levels.

After averaging the calculated phosphorus levels for a certain site in micrograms/liter, we

converted the data into milligrams/cubic meters. We then multiplied by the flow in cubic

meters/second, then seconds/minute, minutes/hour, and hours/day to get our final

calculations in mg/ day. However, since the drainage basins were not all the same size

we also divided by the acreage of the basin to so that we could more accurately

compare them.

Land Use Classification

Class 1 >90% Forested

Class 2 70%-90% Forested

Class 3 <70% Forested

ConclusionAfter comparing the average levels of phosphorus in ug/l and

mg/acre/day, we can conclude that there is a difference

between the drainage basins in the 3 different classes. From

those sites in Class 1 the levels of phosphorus are much lower

than the other 2 classes. Class 2 levels are in the middle and

Class 3 levels are the highest, just as we predicted they would

be. The different factors in the less forested/more agricultural

areas do seem to have an affect on the amount of phosphorus

that flows into the streams. We don’t want these higher levels

of phosphorus to flow into the Lamoille River and eventually

into Lake Champlain because the high levels are not natural,

and not healthy for the lake. When the phosphorus levels in a

lake like Lake Champlain get higher then normal, the growth of

the algae blooms dramatically increases. That’s why

phosphorus is commonly used in fertilizers, it can increase the

growth of plants. When these algae blooms grow, they take up

more oxygen from the water in the lake, which in turn can be

harmful to other organisms also living in the lake. The

excessive growth of the algae on the surface also blocks the

sunlight from penetrating the deeper water, making it almost

impossible for other organisms to live in. This process is called

eutrophication.

AcknowledgementsI would like to thank everyone involved with the EPSCOR Streams Project for all the materials

they provided us, the lab work, and the database. I would also like to give a special thanks to

Lexie Reiss Haselton, the GIS/Database Specialist for all of her help with mapping out the sites

and the drainage basins.

Lamoille Enters Lake Champlain After 85 Miles, Draining 706 Square Miles