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Kelly O.

Piney Z Project Narrative

Located on the east side of Tallahassee, Florida is a chain of watershed called Lake Lafayette. Within this succession of lakes is Lake Piney Z, which has undergone reconstruction in the past few years in order to restore it to an improved condition. Because of its connection to the Florida Aquifer, a major freshwater resource, it is important for the lake to be healthy, pure, and properly maintained. A neighborhood development in the close area of Piney Z recently began, affecting the life and purpose of the lake.

A railroad track runs along side of the approximately 1.06 mile long lake, which has a circumference of roughly 2.60 miles. On the opposite side, a jeep trail follows the water's edge. The picture to the right was taken from the jeep trail. About ten finger dikes protrude into the lake, which were created from piles of muck dredged from the floor of the body of water. When the lake has completely undergone restoration, it will become a place open to the Piney Z community for fishing, picnics, and sightseeing.

The natural cycle of Lake Lafayette was that the lakes drained themselves into the sinkhole and gradually filled back up. Many years ago, the ends of Piney Z were levied off in order to contain the water, and serve for duck hunting and fishing. More recently, the City of Tallahassee drained the lake and scraped the muck off the floor, a process that took a couple of years. The muck was a massive buildup of dead vegetation and runoff from the Piney Z subdivision after years of having nowhere to go; if the lake had not been levied at both ends, the water flow would have carried it away. If the lake still drained naturally, it would flow into the sinkhole. Since neither of these processes occurred for many years, the two or three feet of the lake's floor were made up of useless muck. Bacteria in the muck uses dissolved oxygen in the water that is a necessity to the fish and other life in the lake. This process is called eutrophication. More generally, excessive phosphorus from runoff and erosion nourishes surface waters, causing algae to quickly multiply and cloud the water. This prevents aquatic vegetation under water from getting the sunlight it needs. The algae eventually die and decompose, lowering the amount of dissolved oxygen. This sometimes occurs naturally, but man can also contribute to eutrophication by polluting the water.

Only a portion of the Piney Z underwent the process of being rid of muck; it would have taken too much time and money to do the entire lake. The numerous finger dikes, created for the purpose for places to fish from, were created out of the muck scraped from the floor, and eventually vegetation grew on them.

Karst topography is a landscape in which the characteristics allow for the formation of sinkholes on the ground. Near rivers or small bodies of water, namely in Florida above the Floridian aquifer, a layer of permeable sand lies below the ground above the top of the aquifer. Tertiary limestone is present below that, in which the aquatic system flows. Thus, sinkholes form when perched water lies in the sand. This creates a problem because when sinkholes form they provide a link to the aquifer, which allows polluted water to get into the system where our drinking water comes from.

The Florida aquifer is one of the largest aquifers in the United States, lying beneath Florida, South Georgia, and parts of Alabama and South Carolina and providing a major portion of our drinking water. It is made up of porous limestone and divided into lower and upper sections. Sand, clay, and gravel lie above and below the aquifer. This entire setup of the Florida aquifer encompasses Karst topography. The system of the aquifer is often set off track by varying amounts of rainfall, dredging, and pumping. The sinkhole that exists in Piney Z leads to the Florida aquifer, so the contents of the water should be paid close attention to.

There are certain parameters that serve the purpose of measuring the quality of water. Some of there consist of temperature, dissolved oxygen, pH, turbidity, phosphates, and nitrates. The temperature of the water is important because if man alters it, then the aquatic ecosystem could be disrupted, hurting life in the water. Generally, warm water streams should not exceed temperatures of 89°F. A dissolved oxygen (DO) test measures the amount of gaseous oxygen dissolved in the water. A certain amount is necessary to support substantial aquatic life. The pH of water, the concentration of H+ ions, indicates its acidic or basic nature. A range of 6.0 to 9.0 is acceptable to provide protection for aquatic life. It is rare for the amount to be too high, but if it is then it is harmful to fish. If the concentration is too low, then aquatic life is put under much stress to survive. Turbidity refers to the clearness of water. If water is not clear, the plants underwater don’t receive as much sunlight as they need, and therefore don’t produce the right amount of oxygen. Phosphorus is an element critical for the growth of plants and animals. Rainfall changes the amount of phosphorus in water, stimulating the growth of plankton and aquatic plants and providing food for fish. Thus, the population of fish increases and increases the quality of the water. Too much phosphate results in an abundance of algae, which uses oxygen and eventually leads to eutrophication. Nitrates are one of the most abundant elements. In bodies of freshwater, nitrogen-containing compounds act as nutrients, but nitrate reactions in fresh water result in the depletion of oxygen. Bacteria in water converts nitrates to nitrites, which can produce a serious condition in fish, called “brown blood disease.” In addition, if the nitrite concentration exceeds a certain level and is consumed by humans, it can be detrimental, especially to babies.

Some of the parameters mentioned above were included in the set of information we gathered at Piney Z. Using the Global Positioning System, we first located the latitude and longitude coordinates at the sites where we collected data. We then obtained a beaker of water from the lake and calculated its temperature with a probe and a TI-83 calculator. We also measured the pH with this water sample. Then, using dissolved oxygen kits, we determined the DO, a process that required precision and accuracy.