Health of our Lakes

Submitted by Bobbi Eby on Wed, 2017-06-21 00:00

I finished watching the Health of our Lakes video. It was very informative and eye opening about lakes that I have fished, swam in, and hiked around. I was aware of the algae in Fernan, but I did not realize that it was also threatening CDA Lake and Hayden Lake. I am away with a few questions. What causes the phosphorous? Is it from the mining? How do the lake’s residents contribute to the phosphorous problem? What can they do to minimize this? I found the floating wet lands an aesthetic solution, and am interested to hear more about the success or lack of in the future.   


cknigge's picture

Bobbi a big source of phosphorus is our fertilizers that help keep our lawns nice and green. There is also phosphorus trapped naturally in rocks and sediment. When these rocks erode then that phosphorus and nitrogen is dumped into the lakes and streams. Mining practices around the turn of the 20th century weren't the best (obviously not their fault....they had no idea about the impact of phosphorus on the ecosystems) and those mining practices helped contribute to the large amount of poisonous metals and phosphous loads into the CDA and Silver Valley area lakes. Installing wetlands to help absorb the excess is important to keep these levels down.

Katie Mosman's picture


Phosphorus is one of the three most important plant nutrients and is often included in fertilizers (the other two are nitrogen and potassium).   It supports early growth, root development, and photosynthesis in plants--which is great for our lawns! The excess in nutrients is a result of that fertilizer being carried off the lawns into the water system (by poorly timed rain or irrigation--this is made worse when too much phosphorus is applied). Once in the water system, the algae are the first ones to this smorgasbord of excessive plant food, so their growth takes off! 

How can we help? Keep the nutrients in the soil! Follow fertilizer instructions to a T, including checking the forecast and planning irrigation.  The best thing we can do is only applying fertilizer when or where we need it--which can be determined with some easy at-home soil test kits.  On a large, production scale, this is called "precision agriculture" and it saves money and resources.  

Think of it this way. It's like if you had a couple bug bites, but then you applied Benadryl cream to your entire body. And sometimes, you don't even have bug bites, you just did it because it's summer and that's what you do and you do it at least once every summer.  That's not to say Benadryl cream is bad though, when the itching on that bug bite kicks in, it's relief straight from heaven! Precision fertilizer application saves money, saves resources, and protects the environment. Win-win-win! 

Eric Rude's picture

In the early history of chemical fertilizers (and until recent decades), farmers often did use fertilizer the way you describe wasting Benadryl. Fertilizer companies, out to make big bucks, encouraged over-application. They would often tell the farmers that they needed to apply more fertilizer because so much was being lost to run-off and wind. Then, of course, that extra fertilizer ends up in the watershed, and gets more concentrated as it moves downstream (with all the additional farms adding their extra fertilizer). Eventually, we get massive eutrophication (if you add fertilizer to bodies of water, you get lots of growth of algae, but algae blooms can destroy other life in the water). On a large scale, we end up with areas like the dead zone in the gulf of Mexico. See for more info about this.

Katie Mosman's picture


You are absolutely right. In the early 1900s, there was an enormous leap in technology used for agricultural production, leading to the “Green Revolution,” largely thanks to the work of Norman Borlaug, mechanization of labor and application of fertilizers and pesticides allowed yields per acre to skyrocket, preventing malnutrition and saving the lives of millions, but there were obvious consequences on the environment. Sedimentation of waterways from erosion and eutrophication are a few famous examples.

Many farmers recognize this and are educating themselves on more sustainable practices and implementing them in their production, but not all to be sure. Precision agriculture is one example of this, no-till farming is another. The problem is, money and education are the limiting factor. Precision application of fertilizer, for example, requires equipment that utilizes GPS and GIS technology as the tractor and sprayer move across the field. The tractor uses a GPS to read where it is in the field, then access GIS information that may include soil pH, soil moisture, and specific nutrient levels, then uses a computer algorithm to apply an appropriate amount of fertilizer. However, the farmer must be able to afford the expensive tractor and sprayer to utilize this practice. In addition, they need to have the time, equipment, and resources to collect that data and keep track of all the information. No-till practices increase the organic matter in the soil, improve yields over time, increase water holding capacity, reduce the need for fertilizers, prevent compaction, and balance the pH--however, it can take years to see these benefits. 

Many farmers can see the benefit of these practices, but still don't implement them, and it comes down to money. Due to urbanization, fewer farmers can afford to own much of their own land anymore, so they are forced to always think in the short term--what will pay my operating expenses this year so I don't go broke? Probably tilling (mechanical breakdown of organic matter to release organic nutrients more quickly), planting wheat—again—(one of the higher value crops in North Idaho), and pouring on the nitrogen (wheat uses up a lot of nitrogen, so it’s heavily applied on these fields, which over time, makes the soil more acidic, so the plants fare worse, and uneducated farmers will add more nitrogen next year). No-tilling rental land would be like installing new windows, insulation, and solar panels in a rental home. The sprayer/tractor set up I described would be approximately $100,000 to get set up—this doesn’t include data collection. Planning and preparing with a long-term mindset is a luxury, and many people can't afford it. Should I pay back my students loans or should I save for retirement? Or, if I buy in bulk from Costco, I can save money per unit, but it's going to cost me more money up front. 

So, unfortunately, it's not as widespread as is ideal, but it's gaining momentum with education. The best thing we can do to encourage responsible, sustainable practices is support agriculturists that use these practices is give them our business.  Every dollar we spend is a vote for what we want to see more of in the market. So, if more of us buy local from agriculturists using sustainable practices, these businesses will become more successful and widespread. But buying the cheapest food possible, we unfortunately perpetuate the cycle of cheapest production in the short term possible, which is not what's best for the environment and is not sustainable long term. Americans spend a smaller percent of their income on food than any other country in the world. For real change to happen, we, as consumers, need to make a shift in what and how we are buying our food. It will be more expensive, but it will be what’s best for everyone in the long run.

Best case scenario in my opinion? More people getting back to agriculture and producing more of their own food. Smaller scale agricultural production utilizing sustainable practices would be a dream and the benefits on the environment would be incredible Also, it’s active and out of doors! However, it’s hard work and time consuming, so it’s difficult to get people on board. But it also seems to be an option that’s becoming more popular, so I hope it continues!