Soil Erosion and Water Pollution

The relationship between water quality and soil erosion cannot be overemphasized. Soil erosion and residue management, especially surface water runoff, influence water quality. A silt fence, sometimes called a filter fence, is a temporary sediment control barrier used on construction sites to protect water quality in nearby waterways from sediment in stormwater runoff.

The problem with silt fences is that they only filter sand and silt, clay and nutrients flow through the fences.  Placing a berm of compost on the low side of silt fences adds the capacity to filter out clays and nutrients. Compost contains both positive and negative charges that attract both positively and negatively charged elements and clays.

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Don't Let Leaves Litter Lakes

The beautiful fall colors will soon give way to barren trees and piles of fallen leaves around our yards and neighborhoods.  The leaves decompose and restock the soil with nutrients and organic matter.

However, those decomposing leaves may eventually make their way into lakes and rivers.  They get washed down streets and into storm drains and will feed unwanted algae growth the following summer.

In the Mississippi River-Twin Cities watershed 87 of the 180 lakes studied didn't meet water quality standards because of excess nutrients — that's about half the lakes! And leaves are a major source of the problem. Depending on the lake, leaves might account for 60% of the excess nutrients in these lakes.

Here’s what you can do with your autumn leaves:
·         Rake the leaves that have accumulated along your curb, sidewalk and alley
·         Never trash or burn your leaves
·         Put leaves in your backyard compost pile
·         Use leaves to mulch your garden and lawn
·         Drop leaves off at a compost site

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Fertilizers as Water Pollutants

Article Credit: wisconsinlakes.org

Fertilizers, leaves, grass clippings, eroded soil, and animal waste are all sources of nutrients, including phosphorus. Phosphorus is main nutrient that drives eutrophication (premature aging) in most lakes. Relatively small amounts of phosphorus can cause water quality declines. A concentration of 25 parts per billion of phosphorus in water can promote excessive algae growth in lakes.

Phosphorus—an essential nutrient for plant growth—is a common ingredient in many lawn and garden fertilizers. However, the same phosphorus that helps keep lawns green is also the primary nutrient that turns lakes green with algae. Algae blooms can turn lakes into a thick, smelly green soup that is undesirable for swimming and other recreation. Too much algae clouds water and blocks sunlight from reaching aquatic plants; it also lowers the oxygen levels in the water which can cause fish kills.

Soil can retain only so much phosphorus and plants cannot absorb more phosphorus than they can use. Spreading manure and other fertilizers on lake watershed soils already saturated with phosphorus contributes to chronic nutrient loading, as nutrients can run directly into the lake and/or leach into our lakes from groundwater for years.

Excess algae and aquatic plant growth caused by an over-abundance of nutrients can impact boating and other water recreation and increase lake management costs for lake groups.

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Fire-Retardant Chemicals Fight Wildfires

There are currently dozens of large wildfires burning over 7.8 million acres across western United States.  Many blame global warming for the increased wildfires, as temperatures rise and droughts continue to plague much of the U.S.  Fire seasons are longer and causing more frequent, large-scale, high-severity wildfires.  The risk of large wildfires is expected to increase sixfold by mid-century.

These wildfires cost billions to battle, destroy property, displace wildfire, and are deadly; many firefighters have lost their lives battling the blazes.  The smoke is dangerous to the heart and lungs and we can’t help but ponder what the fires impact is to the water.

Hundreds of thousands of gallons of fire-retardant chemicals (LC95A) are being dropped by air tankers to shield homes and protect firefighters from the wildfires.  Laced with ammonia and nitrates, the chemicals have the potential to kill fish and taint water supplies. 

New rules prohibit the application of fire-retardant chemicals within 600 feet of waterways.  Air tanker pilots and crew commanders now are required to carry maps that identify sensitive terrain — such as areas where greenback cutthroat trout and Pawnee montane skipper butterflies are monitored as sentinel species.  But if wildfires threaten people, the chemicals are applied regardless of the location. 

Forest Service fire managers acknowledge concerns about toxic fire retardants degrading habitat and watersheds, yet they rely upon the bombers to protect houses and firefighters from the potentially catastrophic wildfires.  LC95A air tankers target houses and power grids; the retardant cools and coats fuel, depleting fire of oxygen and slowing the combustion.  A layer of retardant can slow the fire for about two hours which can be enough time for water to actually douse the flames.

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10 Reasons to Care about Aquatic Invasive Species

Written by Madeline Seveland, Education Coordinator with Carver County Water Management

Invasive Species have been steadily gaining more interest with lawmakers, interest groups and the public since the introduction of zebra mussels into Lake Minnetonka and the threat of Asian carp in the Mississippi River. Here are the top ten reasons you should care about preventing the spread of AIS.

10.  CLOGGING: Aquatic invasive species can reproduce very fast and both plants and animals can form dense mats/colonies that clog waters affecting transportation (canals), hydropower and irrigation (ditches). In the early 90s, Hydrilla caused the shutdown of a hydro-electric plant resulting in a record fish kill and the company has spent more than $14 million in control since. Zebra mussels clog intake pipes all over and ruin boat motors by clogging the cooling intake. In the Great Lakes, the annual damage and control costs of zebra mussels who clog intake pipes at electric power plants and water supply facilities is $480 million.

9.  POOR WATER QUALITY: The Great Lakes Water Quality Agreement notes that AIS degrade water quality by increasing turbidity (sediment & algae) and nutrients, reducing dissolved oxygen and concentrating toxins. An example found in many Minnesota lakes and rivers is common carp. These fish are “bottom feeders” and their feeding disrupts shallowly rooted plants muddying the water and releasing phosphorus that leads to algae blooms.

8.  SPREAD OF DISEASE: Many parasites and bugs benefit from thick patches of vegetation. One example is swimmers itch. Eurasian Water Milfoil (EWM) provides good habitat for the parasites that cause swimmers itch (Cercarial dermatitis and Schistosome dermatitis) increasing their numbers.

7.  RECREATIONAL IMPACTS: Lake Tahoe in CA is infested with Eurasian Water Milfoil (EWM).  Water based recreation trips to Lake Tahoe are conservatively estimated at bringing in between $35 and $45 million a year. EWM decreases water quality, clogs boat motors and cooling intakes and the spread of EWM could lead to decrease in recreational uses. Just a 1% decrease in recreation would drop the economic recreational income $500,000 a year.

6.  DECREASE IN PROPERTY VALUES: A paper written by Eric J. Horsch from Stratus Consulting and David J. Lewis from the University of Wisconsin analyzed property values on 170 lakes in northern WI and found property values fell 13% after invasion of Eurasian Water Milfoil. Other studies have found property values to drop 20-40%.

5.  WILDLIFE HEALTH: In addition to the loss of habitat, food, and shelter that affect wildlife when an invasive species moves in, we can add disease. Great Lakes scientists are researching their theory that zebra mussels promote conditions for avian botulism (botulism type E) to grow. It is one of the most toxic substances on earth. On the shores of Lake Michigan it has been the cause of thousands of bird and other wildlife deaths over the past few years.

4.  HUMAN HEALTH: Invasive aquatic plants have become so thick they increased the risk of drowning. One of the most well documented stories took place in Royal City, WA when two men jumped into Red Rock Lake to rescue a boy who became entangled in EWM.  The boy and one man were rescued, the third was so entangled in weeds it took five divers to disentangle his body. Adding to that, zebra mussels have razor sharp shells that can leave painful wounds on your feet if stepped on.

3.  ECONOMY: Much of Minnesota’s economy relies on tourism. Hospitality Minnesota is the third largest employer in the state which includes restaurants, lodgings, resorts & campgrounds, etc.  Much of this industry relies on healthy lakes and rivers. Waters with AIS infestations will see fewer users leading to reduced business and lost jobs. John Madsen, an Associate Research Professor in the Geosystems Research Institute and the Department of Plant and Soil Sciences, Mississippi State University put it simply, “Managing these species economically beats not managing them.”

2.  FISHERIES: Zebra Mussels may clear up the water, but they do so by removing phytoplankton which is the very basis of the food chain. Without phytoplankton, zooplankton populations decrease, resulting in a decrease small fish (planktavores) and then a decrease in game fish (piscivores).  In addition, the clear water allows more sunlight to reach the bottom of the lake resulting in more aquatic plant growth. If there is an invasive plant like EW milfoil established, its population can explode. In short, ZM could = more weeds and less fish.

1.  LONGETIVITY: Many of us will have children and grandchildren. When we are gone we will be leaving our favorite fishing spots, our lake cabins, our tourism businesses, and our stories to our children and grandchildren and will hope they too can enjoy thrill of catching fish, boating, or walking on the beach without risk of cutting up their feet.

Information and examples for this article came from the following sources: Environmental Protection Agency, Journal of Weed Science, MN DNR, MN Sea Grant, WI Sea Grant, Great Lakes Fishery Commission, and MN Dept. of Natural Resources.