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Protecting Our Lakes: Why Phosphorous Matters.

March 11, 2008 - A highly potent threat to our lakes, rivers, and streams is lurking in our midst, just waiting for the first flow of snowmelt, the first drops of rain, or the first sprinkles from a garden hose. Invisible, yet capable of causing serious long-term damage, the threat is known as phosphorus, element #15 on the Periodic Table of Elements.

Phosphorus is naturally occurring and is found in abundance in soil and decaying organic material. As an electromagnetically charged element, it bonds to small particles of soil and clay. When soil and clay particles go across the landscape as run-off from roads, driveways, roofs, ditches, gardens, lawns and parking lots, phosphorus hitches a ride. Because everything flows down hill, phosphorus eventually ends up in our lakes and streams.

When present in low concentrations in the water column, phosphorus is beneficial. It is a nutrient that is essential to the growth of plants. It is utilized by everything from pond weeds to single-celled algae that provide food and cover for all the organisms in the food chain.

However, when it is present in high concentrations, it fuels the explosive growth of algae and the formation of "blooms." Slimy, foul-smelling and disgusting to look at, algae blooms can occur virtually overnight and may last several months. When they die, they release phosphorus back into the water. Depending on factors such as the flushing rate of the water body and the size of the watershed, the concentration of phosphorus can remain dangerously high for decades.

Studies have shown that the impacts of algae blooms are expensive, immediate and persistent. In addition to emitting a foul odor, these unsightly masses of algae can kill fish, reduce recreational activities, reduce property values and in some cases produce toxins that have been known to kill pet dogs and other mammals.

Every year, hundreds of algae-based "fish kills" are reported throughout the country. As algae blooms decay, they rob the water of oxygen, leading to the death of thousands of prized game fish and fish desired for human consumption. In cases where a bloom lasts a month or less, a partial fish kill usually occurs. In cases of major fish kills, a water body may need expensive game fish stocking and may take years to recover. In the meantime, recreational fishing and the associated purchases of food, lodging, and gear decline.

A secondary economic impact of fish kills is the reduction in non-fishing, water-based recreation. Simply put, people do not want to swim in waters filled with floating fish. Nor do they want to swim or operate their boats in thick, green, soupy water. Deterred by the presence of algae blooms and/or dead fish, visitors take their cash and credit cards elsewhere, often with staggering economic impacts.

For example: Possum Kingdom Lake in Texas suffered an economic loss of $2.8 million or a 5 percent drop in its economic output due to algae blooms that occurred between 2001 and 2003. In addition, its state park experienced a 57 percent decline in visitors due to the bloom in 2003. Well-known for its recreational opportunities and dependent upon tourism for its livelihood, Possum Kingdom sustained a crushing blow as a result of phosphorus pollution.


Algae blooms and associated declines in water quality also have negative economic impacts on property values. Studies conducted in both Minnesota and Maine demonstrated that shorefront property values decreased as the clarity and the quality of water declined. For example, as a result of a one (1.0) meter loss in clarity on one of Minnesota's lakes, the estimated front foot value of shorefront property declined from $516.23 to $218. As a result, the combined value of all the properties on this lake declined by over $150,560,122.

Finally, both the Maine and Minnesota studies determined that despite improvements made in water quality on a degraded lake, property values do not completely rebound; once the value is lost, it can not be fully recovered. Thus, declines in water quality can permanently impact individual homeowners and the tax base of their towns and plantatioris.

Finally, swimming in, or ingesting toxic algae has been blamed for non-fatal illnesses in humans and the painful deaths of pet dogs, livestock and wild animals. As an example, a 2004 bloom in a Nebraska lake sickened over 50 people with headaches, diarrhea, and vomiting. In addition, it killed five dogs, several livestock, and a number of wild animals. Similarly, several dogs died on Lake Champlain in Vermont after drinking algae tainted water.

While the impacts of phosphorus pollution can be significant, there are strategies and techniques (aka Best Management Practices or BMPs) that when properly installed and maintained can reduce the amount of phosphorus running off into our lakes and streams. Some of the strategies are relatively simple and inexpensive while others are more sophisticated and costly.

Regardless of their cost, each one of them needs to be properly installed, maintained, and repaired to effectively control or buffer the flow of phosphorus. In the absence of this maintenance and regular repair, many BMPs become completely ineffective. As a result, they allow the unchecked flow of phosphorus and the inevitable degradation of our lakes, streams and ponds.

SOURCE: ORIGINAL IRREGULAR

DATE: 02-27-2008

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