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High Nutrients in Our Bayous; Tips for Reducing the Problem

LAKEWATCH is a volunteer citizen science program provided by UF IFAS.  These volunteers use their own boats to sample water at three stations in their assigned body of water.  These samples are analyzed back on campus for nutrients (total nitrogen and total phosphorus), algal (chlorophyll a), water clarity, and salinity.  Samples are collected every other month.

Lakewatch is a UF IFAS citizen science volunteer program.

The 2020 report indicates that our bayous (particularly, Bayous Chico and Texar) have higher levels of total nitrogen than the other bodies, and that Chico is higher in total phosphorus.

 

Bayou Texar – total phosphorus (17-18 µg/L), total nitrogen (600-800 µg/L)

Bayou Chico – total phosphorus (20-30 µg/L), total nitrogen (350-600 µg/L)

Bayou Grande – total phosphorus (16-19 µg/L), total nitrogen (320-340 µg/L)

 

For comparison

Lower Perdido Bay – total phosphorus (15-16 µg/L), total nitrogen (350-360 µg/L)

 

The concern with high nutrients is the possibility of generating an algal bloom, which in turn will lower the dissolved oxygen when the bloom dies and cause a fish kill.  We are lucky there have been no algal blooms or fish kills in our waters this year that can be attributed to this.  That said, you would still like to get the nutrient levels down.  How can we do that?

 

TIP #1 – REDUCE FERTILIZER USE

 

Nitrogen and phosphorus are both important components in lawn fertilizers.  But our lawns need fertilizer, so how do you reduce?

  • Consider native plants in the yard. They may need fertilizer to kick start them but down the road (if you select the right plants for your yard) will not need fertilizer or water – this saves a lot of money and reduces fertilizers that could potentially end up in our waterways.  Read more about Florida Friendly Landscaping at https://ffl.ifas.ufl.edu/.
  • Find out what nutrient requirements you yard needs. Many lawns in our area are sandy and low in nutrients, so they need a boost – but not all.  Visit the county extension office for a soil sample bag.  For a small fee, UF IFAS will analyze your soil and let you know which nutrients you might need to make your lawn healthy.  You may be able to reduce fertilizer use this way.

Animal waste can become a problem in high density areas.
Photo: Molly O’Connor

 

 

TIP #2 – REDUCE ANIMAL WASTE

 

As you might guess, animal waste is full of nitrogen.  It is a product of life.  Wildlife does produce, and release, waste which can increase nitrogen levels in the environment – but this is totally natural.  Nitrogen IS needed by the system and a source of food for plants and thereby a source of energy for the animals. But too much nitrogen in our waterways can create the algal blooms we are hoping to avoid.  Though we think the bigger issue is human waste, reducing access for animal waste to reach our waters is a good practice.  In this case we are talking about domestic animals – our pets and livestock.

  • Most people do pick up after their pets, but not all. With the number of pets being walked in our neighborhoods each day it can have an impact if we do not.  Within the city, there are locations near parks where the city provides bags for you to use and we recommend everyone use them if they do not have their own.
  • Most of the livestock owners are north of the interstate. For cattle and horses, removing their waste from an open field is not an option.  But for some other livestock breeds, there are options.  If you are in a situation where this can be done, we recommend you do.  This can be used in composting for fertilizer in lawn and gardens.  There are proper methods for composting, and we recommend you contact your county extension office to learn more.

Florida Friendly Yard requires few chemicals and little watering.
Photo: UF IFAS

 

TIP #3 – LEAF LITTER

Nitrogen is a common element in most organic compounds associated with life.  Proteins, enzymes, and more have nitrogen associated with them.  It is an important element in sustaining life and obtained by most living creatures when consuming things.  It is stored and used within the body but when creatures die nitrogen is returned to the system for others – recycled.

 

So, it is with leaves and grass clippings from our yards.  Normally, these would remain on the landscape and be recycled back into the system by bacteria.  But when piled on the side of the street after a day of working in the yard they are subject to being “washed” into local waterways where aquatic bacteria do the same – releasing nitrogen into the aquatic system.

 

Simple tip – do not leave your yard clippings and leaves on the side of the road.

But then you ask – “so, what do I do with them?

  • Some people will use a mulching mower and leave them on the landscape to re-fertilize their lawn. This is an option.
  • Some will pile them in their yard on the side of the road – in a sense keeping them from “washing” away. This works okay.  One problem people have with this plan is that the trash removal folks use large grabbing “claws” to place the debris in their trucks.  These usually leave a “hole”/depression in their yards they are not happy with, so resort to placing them back into the street.
  • For those concerned about the “claw man” digging their yard, you can place the leaves and clippings in bags, and these then placed on the side of the street. More and more people are choosing this option.  However, we do recommend if you choose this to use the paper lawn bags sold at area “do-it-yourself” stores.  Plastic bags work but the county prefers to mulch the yard waste and then give away free mulch.  They cannot do this with yard waste in plastic bags.  By the way, you can get free mulch from the county landfill, but it must be covered before you can take it away.  Check with the county landfill on their rules.

These containers can be found at stations scattered across the county.

TIP #4 – SEPTICS AND SEWERS

 

Our final tip will focus on septic tanks and sewers.  Here, of course, is where human waste goes.  As with animal waste, human waste too is full of nitrogen and can cause multiple problems if it enters local waterways.  Theoretically, you would think the chance of human waste escaping these systems would be low, but septic tanks were not really designed to keep nitrogen held within and sewers have a tendency to “overflow” during heavy rain events.

  • With septic tanks the best thing you can do is to maintain them and have a scheduled maintenance program. They work fine if placed in the right location during building, have an adequate drain field, and you do not flush anything down the commode that was not meant to be flushed into your drain (septic tanks can back up as well).  A regular maintenance program would include an inspection, possibly pump out, every five years.  The jury is still out on products that can be flushed and help your septic tank.  The idea is to have healthy bacteria in there to break the waste products down.  Anything that would impede these bacteria from doing their job would not be desirable.  Food and other items flushed can be broken down, but the time required may be problematic and nitrogen levels will definitely increase.  It was meant for human waste so only human waste should be flushed.  NOTE: most flushable wipes can be flushed but they do not breakdown and can cause back-ups and overflows.  We do not recommend these products be flushed.  A plug of such wipes was found in the sewers of London that was about the size of a city bus, this is a problem.
  • Sewers are designed to collect and move the waste to the treatment plant offsite. However, flushable wipes, bacon grease, and even milk have been known to “clog the arteries”.  These clogs can cause sanitary sewage overflows where the sewage backs up and exits via the manhole covers out into the streets, or even back into your home.  Again, flush only waste and toilet paper down your commode.  The Emerald Coast Utility Authority (ECUA) has a program called FOG (fats, oils, and grease) to help you better understand this problem and they provide 1-gallon plastic jugs for free to place your grease and oil in.  These can be exchanged for clean jugs at locations around the county (there is one at the county extension office) and it is free.  Find out more at Fats, Oils & Grease (fl.gov).

With a few behavior changes on our part we may be able to reduce the nitrogen levels in our local waterways and reduce the chance of an algal bloom or fish kills.  If you have more questions on this problem, contact your local county extension office.