WSE 187 Spring 2000
Investigation of Ground and Surface Water

INTRODUCTION:

            There are several bodies of water on Stony Brook University's campus including Roth Pond, wells, and streams. In our investigation on the campus we hypothesized that all the bodies of water were connected.

            In order to begin conducting experiments to confirm possible connections between the bodies of water, it is imperative to consider Long Island's water table. The water table is the first point in the ground that consists of 100% saturation and 0% air space. If the water table is found above ground we find bodies of water such as streams, ponds, lakes, and bogs.

When the water table is found beneath the land surface, we find aquifers which are a source of freshwater.

The water table is not the only source of surface water. The term perched is used to describe these bodies of water which are formed due to an impermeable layer of clay. Rather than being connected through the water table, these perched bodies contain water from precipitation that cannot permeate the ground. From this knowledge of Long Island's surface and ground water, we can make a conclusion regarding the water on campus by comparing the physical and chemical properties of each body of water.  

METHODS:

            Bodies of water that are connected will most likely have similar properties. We used different chemical tests to determine the pH, total dissolved solids (TDS), and Dissolved oxygen (ppm) and compared them. We also took into consideration the temperature and the elevation of the ground and the water.

First we collected water samples from Roth pond, a small stream, and a well on campus. We used a bailer to collect the samples.

At each site we measured and recorded the temperature.

At the well aside from collecting the sample, we also determined how far down the water surface began from ground level. We measured how far the string from the bailer had to descend in order to hit the ground water. We then had to measure the height of the pipe coming out of the ground and subtract from the total length of the string.

After collecting all of the samples we went back to the laboratory to perform chemical tests on the samples. We determined the pH by adding a drop of pH indicator to each sample. To determine the total dissolved solids we used an electronic instrument and inserted it into the sample and recorded the reading. To calculate the approximate dissolved oxygen in the samples we again used a different type of indicator and compared the colors to a standard.

DATA:

Roth Pond

North Culvert Pipe

Well

Workstation

ANALYSIS:

   To examine our hypothesis, water was taken from four different sites to be observed and analyized.  These four sites were : Roth pond, North & South culvert pipes, and the Well near the power plant.  The water samples collected were tested for the their water temperature, pH, dissolved oxygen, and the total dissolved solids.  There were surpising differences in the  water temperature of the sites.  The water from north culvert pipe had the lowest temperature of 5°C while the South culvert pipe had a temperature of 17°C.  Water from Roth pond had the second lowest temperature of 10°C.  Water from the well has the highest temperature of 18°C.  The pH of the four sites were very similar as indicated from the above table. The amount of dissolved oxygen had a slight variation where the highest amount was found from water of Roth pond of 10 ppm and the lowest from the North culvert pipe of 7 ppm.   The amount of total dissolved solids also had small differences.  Water from Roth pond had the least amount of 50 ppm and the North culvert pipe had the highest amount of 82 ppm. 

      The  elevation of the ground surfaceand the hydraulic head was also measured. The Roth pond had the highest elevation of ground surface and hydraulic head of 139 ft, which is the highest point on campus.  The well had the lowest elevation of ground surface of 105 ft. and lowest hydraulic head of 21 ft.  The hydraulic gradient was measured using the hydraulic head measurements and the distance that we got from the well to the stream and from the well to the pond.  Using these measurements we calculated the flow rate from the well to the stream and from the well to the pond.  We found that the flow rate from the well to the stream was 8.2718 cubic meters per day, while the flow rate from the well to the pond was 3.442 cubic meters per day.

CONCLUSION:

   From the similarities in the pH, dissolved oxygen, and total dissolved solids, we might conclude that these three sites are connected by an underground watertable.  However, from the elevation differences and temperature differences, we could conclude that they are not connected.  There is also a big difference in the flow rate which tells us that they can't be connected by a watertable.   Along with that, the elevation of the Roth pond is the highest elevation on campus which is above the water table that connects the stream and the well.  Since there is no other point on campus that can provide groundwater, Roth pond can not be connected through the watertable to the other two sites.  From all the data, measurements and common sense we can finally conclude that our hypothesis is incorrect.