Does this picture look familiar? Anyone who has been to Lake Eau Claire knows exactly the feeling that the person who took this picture shared, yuck. Phosphorus is one the of the main reason for algae growth. Phosphorus is brought into lakes through tributaries and turnover from sedimentation on the bottom of the lake.

By: Dan Carey

How can I convert the data to useable figures regarding total lake area or volume? What ways can I represent the result?

How can I measure and calculate the amount of water leaving the basin? How can I measure and calculate the amount of water leaving the basin? What factors needed to be measured and taken into account to know about the volume of the lake? Where is the most phosphorus coming from, the sediment or the tributaries?

The lake has water quality problems and it has to do mainly with chlorophyll and phosphorus.

Lake Eau Claire annually has a very large abundance of algae growth every year. This can be because of the pollutants that are introduced by the following tributaries: Hay Creek, Muskrat Creek, and the Eau Claire River. Lake Eau Claire is a basin, so it has a faster than normal turnover rates when it come to lakes.

When the water is entering and leaving the basin, that turnover/flow causes sediment to be kicked up, introducing “old” pollutants back into the lake. The most common habitat that the tributaries wind through is mostly agricultural areas and county forest. Also, two out of the three tributaries have quite poor water quality at the mouth: Muskrat creek the North Fork of the Eau Claire River.

The next mission I had was to find the volume of the lake so that I could use it to calculate the loading and “unloading” of Phosphorus and sediment. So I took a map of Lake Eau Claire and cut out each depth of the lake. Then I set up proportions that had to deal with the known size and the weight out of a whole of the sections of the lake.

After this, it was time to start getting tests done for phosphorus and inflow/outflow. So I went to four designated sites, which will be specified later, and I took bottles filled them up and I took the flow with the flow meter at each site.

After I finish all of the outdoor testing, then it was time for a the long, drawn out indoor testing for phosphorus. The directions for the procedures came from the “HACH Test ‘N Tube procedures” packet. I went out to test, then came back to finish it 7 times.

Field methods were quite simple. The first of the two, the flow meter, was turned on and the propeller end was stuck in the water and I waited till the ft/sec speed stopped going up, and then I would mark it down. The second thing I would do would be to fill up two bottles per site, with water, and mark down the number on the bottle.

This object is a flow meter which measures how fast the water is moving in feet per second. It is hooked up to a graphing calculator which displays the speed.

Sample bottles were used to hold samples of water from each of the four sites so that they could be taken back to the lab to be tested for phosphorus.

The labs methods weren’t quite as simple. I had to follow the Hach Test n’ Tube P Testing step by step. This process, in a whole, took about 2 hours to complete. Sediment testing took a couple of days to complete.

The Hach Analytical Procedures Test n’ Tube Phosphorus Testing Manuel was used for the procedures for testing for phosphorus when the samples were taken back to the lab.

This is the Spectrophotometer and it is used for measuring how “turbid” or how much phosphorus is present in a solution by shooting light waves through it and seeing how able the waves are to get through.

The Hach test tubes where used in holding the samples and the chemicals needed to test phosphorus. I used 12 test tubes, 3 for each site, to get a better average of phosphorus for each site.

These Hach Test n’ Tube chemicals were used in the testing process. The following chemicals were used: Potassium Persulfate, PhosVer Phosphate Reagent, Sulfuric Acid, and Sodium Hydroxide.

Inflow/Outflow

Phosphorus Loading

I conclude that the inflow of phosphorus into the lake is much greater than that leaving the lake. The highest rate of flow is spring time, and it is more of a gradual thing during the times of summer, fall, and winter. Winter is the lowest time.