Eutrophication Project



The Students: Sarah Davis, Ben Davidson, Cassie Sandmeyer, Jenny Whitehead

The Teacher:
Clinton A. Kennedy


Our Advanced Biology project is based on the following problem:
eutrophication which is a nutrient overloading in any particular
body of water: it is often a result of excessive amounts of nitrates
or phosphates. Cascade Reservoir has become eutrophic because
of nutrients, mainly phosphate, entering the water through point
and non point sources, such as: irrigation, leaky septic tanks,
cattle waste, and storm water run off. Excessive nutrients allow
for excessive algae.

Nutrient levels in bodies of water are effected in various ways,
but one common way is through cattle excretement. Cattle excretement
contains many nutrients, but phosphorus is one that seems to have
damaging effects on bodies of water. High nutrient levels can
be related to cattle being allowed to graze too close to bodies
of water and its impact on water quality has concerned many groups
of people for some time, especially in and around Cascade. Some
fear that water quality is at risk when cattle graze near bodies
of water because 97.3% of the phosphorus ingested by cattle are
excreted and presented with an opportunity to enter the water
shed. Most soils are able to easily absorb phosphorus, but some
groups are still concerned with that little bit of phosphorus
that does escape the reach of the soil and enters into the water
shed. This very scenario is quite common to Cascade and that is
why we have chosen to base our Advance Biology project on something
related to the problems caused by phosphate (mainly cattle excretement).
One particular problem caused by excessive nutrients is outlined
below.

Eutrophication, summed up, occurs when nutrients are plentiful,
therefore allowing algae the food needed for growth. After algae
use up all the nutrients in the top of the water column they die
turning to detritus, and fall to the floor of the lake where bacteria
continue to decompose them. The bacteria use up all the oxygen
at the bottom of the lake. This loss of oxygen is deadly to some
sensitive species of cold water fish like trout and it causes
the water to become slightly toxic caused illness in swimmers.
Not only is the water harmful, but it also releases a horrible
odor making activities like boating, fishing, and water skiing
rather unpleasant. and the nutrients, nitrate and phosphate, originally
used by the algae to maintain life are released back into the
water column starting the process all over again. This process
continues as water quality is slowly destroyed. This is the situation
occurring in Cascade Reservoir, simplified of course, and that
is why our group has become interested in the problems related
to the reservoir.

As eutrophication has been examined and the problems with the
lake have been becoming a large concern environmental groups have
focused on trying to fix these problems. Irrigation is just one
point source of nutrients that has been examined by groups concerned
with the quality of the lake. Many have assumed that flood irrigation
contributes a large portion of phosphate to the watershed adding
to the overall problem of eutrophication in the lake. This has
not been solidly proven, as to our knowledge, and that is why
we have chosen to set up a simulated irrigation process. We are
going to attempt to figure out for ourselves if flood irrigation
does indeed allow more phosphate to escape into the watershed
and ultimately the reservoir.

The types of irrigation that we are trying to simulate are: flood,
which consists of allowing water to leach or overflow out of existing
man-made ditches; sprinkler, which consists of sprinkling water
onto soil samples; and natural, which is the same as sprinkler,
but less frequent.

Flood irrigation looks like the below picture, of course in our
project it will be on a much smaller scale. It will consist of
applying large amounts of water over smaller amounts of time in
comparison with that of sprinkler. Flood irrigation will include
supersaturating the soil.

Sprinkler irrigation will consist of watering the soil to the
point of dampness or saturation without flooding or excessive
standing water on the surface of the soil. This is a large scale
picture of sprinkler irrigation.

 

Natural irrigation is very similar to that of sprinkler irrigation.
It will sprinkler the soil to the point of saturation, but on
a less frequent basis that that in sprinkler.

Along with the water being applied to the soil will be cow manure.
This manure will be applied in exact amounts and the same amount
will be applied to each bucket. After this manure is applied the
various types of irrigation will be used. The water passing through
each bucket will be collected and the amount of phosphate in them
will be tested. This resulting phosphate will imply and show which
type of irrigation is indeed allowing the most phosphate to escape
into the ground water and ultimately the watershed and the reservoir.

The actual set-up of our project is an interesting conglomeration
of pieces and odds and ends, put together. Here is a side view
and a top view of our project:

Side View

Top View

As you can see the set-up holds nine buckets each with its own
watering apparatus. The buckets each have holes in which the water
applied well drain. This watering tube as shown in more detail
here:

These tubes will allow us to control the amount of water being
put on the soil over a certain amount of time.

 


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