Conservation Corner

16-Oct-11 Cultural Eutrophication

 Cultural Eutrophication

Lakes in general are a reflection of the watershed that they reside in. When it

rains out the water that cannot be absorbed by the soil is directed by the

nature of the landscape to lowlands, streams, rivers and of course lakes.  The

kinds of material that ends up there is dependent on the type of soils and

vegetation that make up the landscape.

When we as humans change the landscape by clearing the land, pave the roads and

build our cities we create “Cultural Eutrophication“, which is the removal of

the natural soils and vegetation that make up the natural protective barrier to

keep material or nutrients from entering directly into a body of water, which

causes accelerated natural eutrophication of lakes. When this happens “nonpoint

source pollutants” can now enter the lake more easier. These include lawn

fertilizers, pesticides, pet bacteria, metals like lead and zinc, automotive

oils and road materials. A water treatment plant or factory may add a “point

source pollutant” by using pipes that discharge water that reaches the lake,

which need to be taken into consideration in the future.

What does all this Mean?  Eutrophication by itself is the enrichment of water

with inorganic nutrients, organic matter and silt which causes an increase in

biological activity. The rate at which a lake “ages” which is all lakes

eventually fill in and become dry land (sorry lake shore owners) can take

thousands of years to happen.  Our own cultural activities can allow this to

happen in a single generation and the increased lake ageing is called “Cultural

Eutrophication”  The most relevant effect is the algae bloom with a close

following of the shallowing of a lake by silt and soil runoff which in turn

causes shallow rooted plants to thrive, which in turn cause boat navigation

hardships, boats churning up plants and sediment then create a resuspending of

nutrients which can enhance the biological activity all over again. This effect

has appeared in Choo Choo Bay and the Mud Arm over the last 30 years, in a

single generation the Mud Arm has went from being boat user friendly to non boat

accessable today.

Along with the Cultural Eutrpohication effect comes the loss of spawning grounds

for fish and other aquatic species.  Areas have dried up or become contaminated

with silt and algae and the oxygen level no longer supports or sustains aquatic

life in that area.

Controlling nonpoint source pollutants should be the main objective of any lake

management plan. The CLIA is leading the way with a storm water runoff project

at one point on Viking Blvd, which should limit the entry of soils, nutrients

and other materials from entering Coon Lake uncontrolled.  This is only one

project however.  As a lakeshore owner with riparian water rights it is also up

to each individual to make sure that they participate and implement good water

run off practices.  Next time it rains, go outside and actually look at what is

happening to the rain water runoff.  Make sure you have a buffer zone at the

lake shore.  Look around your neighborhood to spot potential runoff hazards and

bring them to the owners or city’s attention.  Things cannot be fixed if we do

not let them know.

Treating storm water runoff is now part of the federal Clean Water Act. 

Cultural Eutrophication is a form of water pollution, we all want to continue to

use and have a healthy lake to enjoy, we all need to take steps to protect it.

It is all the little things that each and everyone of us does that ends up

making a big impact.  The things you decide to do today will have a long term

impact on you and future generations who desire to have a high quality water

environment as their backyard to use for recreation.

Not only important to just lake owners but all property owners who have a

wetland or pond close to them should be aware of the Cultural Eutrophication

effect and take steps to protect them.


21-Mar-10 Spring into Action
22-Sep-09 Boating and Water Pollution
02-May-09 Keeping It Blue!