Many of Florida’s historic first magnitude springs are classified as nitrogen impaired. Image credit: UF/IFAS Communications
Septic systems are an effective means of treating wastewater when they are properly designed, constructed and maintained. Conventional systems are designed from a public health perspective and have been widely used since the 1940s to remove pathogens and protect human health. About 30% of Florida’s population relies on septic systems, which treat and dispose household wastewater drained from bathrooms, kitchens and laundry machines.
However, septic systems were not designed to remove nutrients. A conventional system removes only about 30 percent of the nitrogen that flows into it. Even a well-maintained system will become a source of nitrogen (particularly nitrate-nitrogen) to the surrounding soil in the drainfield, and may leach to groundwater. Excess nitrogen in Florida’s waterbodies can be a contributing factor to ecological community degradation and increases in algae.
What alternatives are there to conventional septic systems?
Many enhanced nitrogen removal technologies exist, but only those approved by the Florida Department of Health (FDOH) can be installed. Conventional septic systems are made up of a septic tank and a drainfield (or leachfield). Advanced treatment systems add steps to conventional system processes to improve contaminant removal. Types of advanced nitrogen removal technologies available include:
- Aerobic Treatment Units ATUs are made of fiberglass, polyurethane or concrete. Unlike conventional systems, ATUs introduce air into the sewage in the tank using a pump. By aerating waste, the organic matter in the tank is broken down faster than in a conventional system. Effluent from an ATU is discharged into a drainfield for further treatment in the soil, just as with a conventional septic system. ATUs require higher energy input than conventional septic systems to power the aerator, and regular operation and maintenance to sustain performance ATU example from the US EPA
- Performance Based Treatment Systems PBTS are specialized systems designed by professional engineers to meet specific levels of contaminant removal based on site and/or situation requirements. There are many proprietary commercial options available. Designs often include an ATU. Like ATUs, PBTS require higher energy input than conventional septic systems to power pumps, and regular maintenance is needed to sustain performance.
- In-Ground Nitrogen Removing Biofilters INRB are also referred to as modified drainfields. These systems are passive, which means they require no electric aerators or pumps to treat wastewater, and maintenance requirements are lower than those for ATUs and PBTS. INRBs are nitrogen-reducing media layers placed underneath a conventional drainfield.
Ammonium-nitrogen in wastewater leaving the septic tank moves down through the Drainfield Area soil and an additional oxygen-rich zone (Unsaturated Nitrification Soil) to promote conversion into nitrate-nitrogen. Wastewater then passes through a low-oxygen, carbon-rich zone to promote denitrification (Woodchips/Soil Mix Denitrification Media). Denitrification is a process by which specialized bacteria convert nitrate into nitrogen gas that escapes into the atmosphere. This reduces the amount of nitrogen that can leach into groundwater.
FDOH provides comprehensive information about advanced treatment systems and requirements on their product listing and approval requirement web page.
Where are advanced treatment systems required?
The short answer is wherever a septic system remediation plan to protect Florida Springs has been put into place. The 2016 Florida Springs and Aquifer Protection Act was passed to protect 30 ‘Outstanding Florida Springs.’ The majority are historic first magnitude springs, springs with flows of more than 100 cubic ft/second. Twenty-four of these springs are identified as nitrogen impaired by the Florida Department of Environmental Protection.
If septic systems contribute more than 20% of the nitrogen load to the impaired spring, a remediation plan takes effect in specific areas (Priority Focus Areas) that are particularly susceptible to nitrogen pollution. Septic system remediation plans require new development to connect to central sewer where available. If this isn’t an option, new construction on lots of less than 1 acre must include advanced nitrogen-removal technology. In the Panhandle, areas around Wakulla Springs and Jackson Blue Springs have remediation plans.
The best source of information about specific remediation plans and whether or not you live in a Priority Focus Area is FDOH. Contact your local County Department of Health Office to find out if you live in a PFA or if you have questions about septic tank requirements, permitting and approved advanced nitrogen-treatment features for septic systems.
For more information and resources about conventional septic systems and advanced treatment system visit our UF/IFAS Septic Systems website.
Senate Bill 712 ‘The Clean Waterways Act’ was signed into Florida law on June 30, 2020. The purpose of the bill is to better protect Florida’s water resources and focuses on minimizing the impact of known sources of nutrient pollution. These sources include septic systems, wastewater treatment plants, stormwater runoff as well as fertilizer used in agricultural production.
Senate Bill 712 focuses on protecting Florida’s water resources such as Jackson Blue Springs/Merritt’s Mill Pond, pictured here. Credit: Doug Mayo, UF/IFAS.
What major provisions are included in SB 712?
Primary actions required by SB712 were listed in a news release by Governor Desantis’ staff in June 2020 as:
- Regulation of septic systems as a source of nutrients and transfer of oversight from the Florida Department of Health (DOH) to the Florida Department of Environmental Protection (DEP).
- Contingency plans for power outages to minimize discharges of untreated wastewater for all sewage disposal facilities.
- Provision of financial records from all sanitary sewage disposal facilities so that DEP can ensure funds are being allocated to infrastructure upgrades, repairs, and maintenance that prevent systems from falling into states of disrepair.
- Detailed documentation of fertilizer use by agricultural operations to ensure compliance with Best Management Practices (BMPs) and aid in evaluation of their effectiveness.
- Updated stormwater rules and design criteria to improve the performance of stormwater systems statewide to specifically address nutrients.
How does the bill impact septic system regulation?
The transfer of the Onsite Sewage Program (OSP) (commonly known as the septic system program) from DOH to DEP becomes effective on July 1, 2021. So far, DOH and DEP submitted a report to the Governor and Legislature at the end of 2020 with recommendations on how this transfer should take place. They recommend that county DOH employees working in the OSP continue implementing the program as DOH-employees, but that the onsite sewage program office in the State Health Office transfer to DEP and continue working from there. DOH created an OSP Transfer web page where updates and documents related to the transfer are posted.
How does the bill impact agricultural operations?
SB 712 affects all landowners and producers enrolled in the Florida Department of Agriculture and Consumer Services (FDACS) BMP Program. Under this bill:
- Every two years FDACS will make an onsite implementation verification (IV) visit to land enrolled in the BMP program to ensure that BMPs are properly implemented. These visits will be coordinated between the producer and field staff from FDACS Office of Agriculture and Water Policy (OAWP).
- During these visits (and as they have done in the past), field staff will review records that producers are required to keep under the BMP program.
- Field staff will also collect information on nitrogen and phosphorus application. FDACS has created a specific form, the Nutrient Application Record Keeping Form or NARF where producers will record quantities of N and P applied. FDACS field staff will retain a copy of the NARF during the IV visit.
FDACS-OAWP prepared a thorough document with responses to SB 712 Frequently Asked Questions (FAQ’s). It includes responses to questions about site visits, the NARF and record keeping, why FDACS is collecting nutrient records and what will be done with this information. The fertilizer records collected are not public information, and are protected under the public records exemption (Section 403.067 Florida Statutes). For areas that fall under a Basin Management Action Plan (like the Jackson Blue and Wakulla Springs Basins in the Florida Panhandle), FDACS will combine the nitrogen and phosphorus application data from all enrolled properties (total pounds of N and P applied within the BMAP). It will then send the aggregated nutrient application information to FDEP.
Details of how all aspects of SB 712 will be implemented are still being worked out and we should continue to hear more in the coming months.
Well-maintained stormwater ponds can become attractive amenities that also improve water quality. Photo credit: Carrie Stevenson, UF IFAS Extension
Prior to joining UF IFAS Extension, I spent three years as a compliance and enforcement field inspector with the local Florida Department of Environmental Protection (FDEP) office. It was a crash course in drinking water regulation, wetlands ecology, stormwater engineering, and human psychology. For about half of that time, I worked in the stormwater section with an engineer, certifying the proper construction and specifications of stormwater treatment ponds built for residential and commercial developments. During a construction boom in 2000-2003, my coworkers and I traversed back roads from Perdido Key to Freeport, trying to catch every new project and make sure it was done right. If they weren’t, it also fell to the 3 of us to make sure mistakes were corrected.
Since 1982, Florida Statutes have required that rainfall landing on newly constructed impervious surfaces (rooftops, streets, parking lots, etc.) must be treated before turning into runoff that leaves the property and ends up in local water bodies. The pollutants in stormwater runoff—heavy metals, fertilizer, pesticides, trash, bacteria, and sediment—are the biggest sources of water quality problems for the state, more so even than industrial and agricultural sources.
The most common stormwater ponds have sandy bottoms, grassed berms, and piped inlets with riprap to slow the influx of water. Photo credit, Michelle Diller
Therefore, new developments are required to treat that runoff. This may be accomplished by several means, including regional stormwater ponds. However, the most common are still curbs and gutters, which drain to an often-rectangular hole in the ground with a chain-link fence around it. Ideally, water pools into these dry ponds while raining, reducing flood risk and holding water long enough to allow it to soak into the soil. Most of the ponds in northwest Florida have sandy bottoms that percolate easily. Maintenance is required, however, and when heavier soils, trash, or muck accumulate they must be cleaned out to function properly. Depending on the geology of any given location, the ponds may need sand filters or “chimneys” added to allow water to soak into the native soil.
Admiral Mason Park, adjacent to the Veterans’ Memorial Park along Pensacola Bay, is an example of a regional City stormwater treatment facility that also serves as a park. Photo credit: Visit Pensacola
If an area is naturally low-lying, close to the water table, or has highly organic, water-holding soils, it may be necessary to construct a “wet” stormwater pond. In these, water stands to a level below an overflow device, and can become a water feature for the development. Many residential developers will sell lots around a stormwater pond as “waterfront property” and a well-maintained one really can be a nice amenity. However, at their core, these are stormwater treatment mechanisms. A wet pond functions differently than a dry one and is dependent on healthy stands of shoreline vegetation to take up extra nutrients, metabolize them, and render them into harmless compounds. Many of these ponds have fountains to aerate the water and keep them from becoming stagnant. The City of Pensacola and Escambia County have several great examples of these types of ponds that serve as regional stormwater detention and community amenities. These were constructed in lower-lying areas to handle chronic problems with stormwater in areas that were built up and paved many decades before stormwater rules came into effect. Many other innovative and newer stormwater treatments exist as well, including bioretention, rainwater harvesting, green roofs, and pervious pavement.
Special care needs to be taken with your septic system after flooding. Image: B. White NASA. Public Domain
During and after floods or heavy rains, the soil in your septic system drainfield can become waterlogged. For your septic system to treat wastewater, water needs to drain freely in the drainfield. Special care needs to be taken with your septic system under flood conditions.
A conventional septic system is made up of a septic tank (a watertight container buried in the gound) and a drainfield. Image: Soil and Water Science Lab UF/IFAS GREC.
A conventional septic system is made up of a septic tank and a drainfield or leach field. Wastewater flows from the septic tank into the drainfield, which is typically made up of a distribution box (to ensure the wastewater is distributed evenly) and a series of trenches or a single bed with perforated PVC pipes. Wastewater seeps from these pipes into the surrounding soil. Most wastewater treatment occurs in the drainfield soil. When working properly, many contaminants, like harmful bacteria, are removed through die-off, filtering and interaction with soil surfaces.
What should you do if flooding occurs?
The U.S. Environmental Protection Agency (EPA) offers these guidelines:
- Relieve pressure on the septic system by using it less or not at all until floodwaters recede and the soil has drained. Under flooded conditions, wastewater can’t drain in the drainfield and can back up in your septic system and household drains. Clean up floodwater in the house without dumping it into the sinks or toilet. This adds additional water that an already saturated drainfield won’t be able to process. Remember that in most homes all water sent down the pipes goes into the septic system.
- Avoid digging around the septic tank and drainfield while the soil is waterlogged. Don’t drive vehicles or equipment over the drainfield. Saturated soil is very susceptible to compaction. By working on your septic system while the soil is still wet, you can compact the soil in your drainfield, and water won’t be able to drain properly. This reduces the drainfield’s ability to treat wastewater and leads to system failure.
- Don’t open or pump the septic tank if the soil is waterlogged. Silt and mud can get into the tank if it is opened and can end up in the drainfield, reducing its drainage capability. Pumping under these conditions can cause a tank to float or ‘pop out’ of the ground, and can damage inlet and outlet pipes.
- If you suspect your system has been damaged, have the tank inspected and serviced by a professional. How can you tell if your system is damaged? Signs include: settling, wastewater backs up into household drains, the soil in the drainfield remains soggy and never fully drains, a foul odor persists around the tank and drainfield.
- Keep rainwater drainage systems away from the septic drainfield. As a preventive measure, make sure that water from roof gutters doesn’t drain towards or into your septic drainfield. This adds an additional source of water that the drainfield has to process.
- Have your private well water tested if your septic system or well were flooded or damaged in any way. Your well water may not be safe to drink or use for household purposes (making ice, cooking, brushing teeth or bathing). You need to have it tested by the Health Department or other certified laboratory for total coliform bacteria and coli to ensure it is safe to use.
For more information on septic system maintenance after flooding, go to:
More information on having your well water tested can be found at:
More Information on conventional and advanced treatment septic systems can be found on the UF/IFAS Septic System website
If your private well was damaged or flooded due to hurricane or other heavy storm activity, your well water may not be safe to drink. Well water should not be used for drinking, cooking purposes, making ice, brushing teeth or bathing until it is tested by a certified laboratory for total coliform bacteria and E. coli.
Residents should use bottled, boiled or treated water until their well water has been tested and deemed safe.
- Boiling: To make water safe for drinking, cooking or washing, bring it to a rolling boil for at least one minute to kill organisms and then allow it to cool.
- Disinfecting with bleach: If boiling isn’t possible, add 1/8 of a teaspoon or about 8 drops of fresh unscented household bleach (4 to 6% active ingredient) per gallon of water. Stir well and let stand for 30 minutes. If the water is cloudy after 30 minutes, repeat the procedure once.
- Keep treated or boiled water in a closed container to prevent contamination
Use bottled water for mixing infant formula.
Where can you have your well water tested?
Contact your county health department for information on how to have your well water tested. Image: F. Alvarado Arce
Most county health departments accept water samples for testing. Contact your local department for information about what to have your water tested for (they may recommend more than just bacteria), and how to collect and submit the sample.
Contact information for Florida Health Departments can be found here: County Health Departments – Location Finder
You can also submit samples to a certified commercial lab near you. Contact information for commercial laboratories that are certified by the Florida Department of Health are found here: Laboratories certified by FDOH
This site includes county health department labs, commercial labs as well as university labs. You can search by county.
What should you do if your well water sample tests positive for bacteria?
The Florida Department of Health recommends well disinfection if water samples test positive for total coliform bacteria or for both total coliform and E. coli, a type of fecal coliform bacteria.
You can hire a local licensed well operator to disinfect your well, or if you feel comfortable, you can shock chlorinate the well yourself.
You can find information on how to shock chlorinate your well at:
After well disinfection, you need to have your well water re-tested to make sure it is safe to use. If it tests positive again for total coliform bacteria or both total coliform and E. coli call a licensed well operator to have the well inspected to get to the root of the problem.
Well pump and electrical system care
If the pump and/or electrical system have been underwater and are not designed to be used underwater, do not turn on the pump. There is a potential for electrical shock or damage to the well or pump. Stay away from the well pump while flooded to avoid electric shock.
Once the floodwaters have receded and the pump and electrical system have dried, a qualified electrician, well operator/driller or pump installer should check the wiring system and other well components.
Remember: You should have your well water tested at any time when:
- A flood occurred and your well was affected
- The color, taste or odor of your well water changes or if you suspect that someone became sick after drinking your well water.
- A new well is drilled or if you have had maintenance done on your existing well
- There has been any type of chemical spill (pesticides, fuel, etc.) into or near your well
The Florida Department of Health maintains an excellent website with many resources for private well users: FDOH Private Well Testing and other Reosurces which includes information on potential contaminants and how to maintain your well to ensure the quality of your well water.
Recently there was a report of high fecal bacteria in a portion of Perdido Bay. I received a few concerned emails about the possible source. Follow up sampling from several agencies in both Florida and Alabama confirmed the bacteria was there, the levels were below both federal and state guidelines (so no advisory issued), and a small algal bloom was also found. It was thought the cause was excessive nutrients and lack of rain.
We hear this a lot.
Excessive nutrients and poor water quality.
What is the connection?
Many people understand the connection, others understand some of it, others still do not understand it. UF IFAS has a program called LAKEWATCH where citizen science volunteers monitor nutrients in some of lakes and estuaries within the state. Here in Escambia County, we have six such volunteers. Some of the six bodies of water have been monitored for many years, others are just starting now, but the data we have shows some interesting issues – many have problems with nitrogen. Let’s look closer.
The nitrogen cycle.
Image: University of Florida IFAS
We have all heard of nitrogen. Many will remember from school that it makes up 78% of the air we breathe. In the atmosphere nitrogen is present as a gas (N2). It is very common element found in living creatures – as a matter of fact, we need it. Nitrogen is used to build amnio acids – which builds proteins – which is needed to produce tissue, bone, blood, and more. it is one of the elements found in our DNA and can be used to produce energy. However, it cannot do these in the atmospheric gas form (N2) – it needs to be “converted” or “fixed”.
One method of conversion is the weather. Nitrogen gas are two molecules of nitrogen held together by strong chemical bonds (N2). However, lightning provides enough energy to separate N2 and oxidize it with oxygen in the atmosphere forming nitrogen dioxide (NO2). This NO2 combines with water in the atmosphere to form nitric acid (HNO3). Which can form nitrates (NO3) with the release of the hydrogen and nitrate (NO3) is usable by plants as a fertilizer… a needed nutrient.
But much of the usable nitrates do not come from the atmospheric “fixing” of nitrogen via lightning. It comes from biological “fixing” from microbes. Atmospheric nitrogen can be “fixed” into ammonia (NH3) by bacteria. Another group of bacteria can convert ammonia into nitrite (NO2), and a third group can convert it from nitrite to the usable form we know as nitrate (NO3). Ammonia can also be found in the environment as a waste product of life. As we use nitrogen within bodies it can be converted into ammonia – which can be toxic to us. Our bodies remove this ammonia via urine, and many times we can smell this when we go to the restroom. Nitrogen fixing bacteria can convert this ammonia to nitrites as well and complete the nitrogen cycle.
Once nitrogen has been fixed to the usable nitrate it can be taken up by plants and used within. Animals obtain their needed nitrogen by eating the plants or eating the animals that ate the plants. In both cases, nitrogen is used for protein synthesis in our bodies and unused nitrogen is released into the environment to continue the cycle.
So, what is the connection to water quality?
You might think that excessive nitrogen (nutrients) in the water would be a good thing. Released ammonia, though toxic, could be “fixed” into nitrite and eventually nitrate and recycled back into life. And you would right. Excessive amounts of ammonia though, may not be converted quick enough and a toxic state could occur. We see this in aquaculture ponds and home aquaria a lot.
Members of the herring family are ones who are most often found during a fish kill triggered by hypoxia.
But what about excessive nitrates? Shouldn’t that be good for the plants?
The concept makes sense, but what we see with increase plant growth in aquatic systems is problematic. Excessive plant growth can cause several problems.
1) Too much plant growth at the surface (algae, leafy vegetated material) can block sunlight to the other plants living on the bottom of the waterway. This can cause die off of those plants and a mucky bottom – but there is more.
2) Excessive plant growth at the surface and the middle of the water column can slow water flow. Reduced water flow can negatively impact feeding and reproductive methods for some members of the community, cause stagnation, and decrease dissolved oxygen – but there is more.
3) Plants produce oxygen, which is a good thing, so more plants are better right? Well, they do produce oxygen when the sun is up. When it sets, they begin to respirate just as the animals do. Here excessive plants can remove large amounts of dissolved oxygen (DO) in the water column at night. If the DO levels reach 3.0 µg/L many aquatic organisms begin to stress. We say the water is hypoxic (oxygen starving). When a system becomes hypoxic the animals will (a) come to the surface gasping, (b) some even approach the beach (the famous crab jubilee of Mobile Bay), (c) leave the water body for more open water, (d) die (a fish kill). This is in fact what we call a dead zone. Not always is everything dead, in many cases there is not much alive left – they have moved elsewhere so we say the bottom is “dead”. Here is something else… as the dead fish and (eventually) dead plants settle to the bottom they are decomposed by bacteria. This decomposition process requires dissolved oxygen – you guessed it – the DO drops even further enhancing the problem. In some cases, the DO may drop to 0.0 µg/L. We say the water is now anoxic (NO oxygen). I have only seen this twice. Once in Mobile Bay, and once in Bayou Texar. But I am sure it happens more often. The local environment can enhance (or even cause) this problem as well. Warm water holds less oxygen and much of the oxygen dissolved in water comes from the atmosphere – by way of wave action. So, on hot summer days when the wind is not moving much, and excessive nutrients (nitrogen) is entering the water, you have the perfect storm for a DO problem and possible fish kill.
4) Oh, and there is one other issue… some of the algae that produces these blooms release toxins into the water as a defense. These are known as harmful algal blooms (HABs). Red tide is one of the more famous ones, but blue-green blooms are becoming more familiar. So now you have a possible hypoxic situation with additional toxins in the water that can trigger large fish kills. Some of these HABs situations have killed marine mammals and sea turtles as well.
Though this process can occur naturally (and does) excessive nutrients certainly enhance them, and in some cases, initiate them. So, too much nitrogen in the system can be bad.
So, what does the LAKEWATCH data tell us about the Pensacola Bay system?
Well, first, we have not had volunteers on all bodies of water for the same amount of time. We currently have volunteers monitoring (1) northern Pensacola Bay, (2) Bayou Texar, (3) Bayou Chico, (4) Bayou Grande, (5) Big Lagoon, and (6) lower Perdido Bay. Pensacola Bay has JUST started, and Big Lagoon has not even started yet (COVID-19 issues) – so we only have data from the other four. Bayou Texar has the longest sample period at 13 years.
Lakewatch is a citizen science volunteer supported by the University of Florida IFAS
Second, this program does not sample for just nitrogen, but another key nutrient as well – phosphorus. When you look at a bag of fertilizer you will see a series of numbers looking like: 30-28-14. This would be nitrogen, phosphorus, and potassium. People adding fertilizer to their lawns should know which nutrient they need the most and can by a fertilizer with a numerical concentration that is best for their lawn. You can have your soil tested at the county extension office. But the point here is that there is more than nitrogen to look at and, as we have learned, more than one form of nitrogen out there. So, what we do at LAKEWATCH is monitor for total nitrogen (TN) and total phosphorus (TP).
Another parameter monitored is total chlorophyll a (TC). The idea is… if there are excessive amounts of nutrients in the water there will be excessive amounts of algae. You could collect a sample of water and count the number of algal cells in the water – but another way is to measure the amount of chlorophyll in the water as a proxy for the amount of algae. Chlorophyll, of course, is the compound within plants that allows photosynthesis to happen. There is a chemical process used to release the chlorophyll within the cells and you can then use an instrument to measure the amount of chlorophyll in the water.
LAKEWATCH volunteers also monitor water clarity. It is true that clarity can be impacted by sediments in the water as much as an algal bloom, but anything that contributes to less sunlight reaching the bottom can be problematic for some bodies of water. This is done by lowering a disk into the water and measuring the depth at which it “disappears”.
For those not familiar with the term salinity, it is the measure of the amount of dissolved solids in the water – what most people say, “how salty is it?”. For reference, the Gulf of Mexico is usually around
35‰, most open estuaries are between 20-30‰.
Below is a table of the LAKEWATCH data we have as of the spring 2020.
|Year of Sampling
||Body of Water
||Total Phosphorus (µg/L)
||Total Nitrogen (µg/L)
||Total Chlorophyll (µg/L)
||Water Clarity (feet)
|2014 – 2018
||350 – 600
||10 – 30
||2.6 – 4.2
||7.0 – 8.2
|2012 – 2017
||16 – 19
||320 – 340
||4.0 – 5.2
||17 – 18
|2007 – 2018
||17 – 18
||600 – 800
||6 – 8
||3.4 – 3.8
||8 – 10
|2014 – 2018
||350 – 360
||5.3 – 6.1
There are a couple of things that stand out right away
(keep in mind some water bodies have not been monitored very long by LAKEWATCH).
1) Phosphorus is not as big a problem in our part of the state. In the peninsula part of Florida there is a lot of phosphorus in the sediments and much of it is mined. You can see this in the average value for the state. Actually, because of this, many of the central and south Florida lakes are naturally high in phosphorus and this is not considered “polluted”. All that said, there are higher levels of phosphorus in Bayou Chico. Which is interesting. More on solutions in a moment.
2) We have a lot of nitrogen in our waters. Bayou Texar in particular is much higher than the state average. More on this in a moment.
3) We have a little more chlorophyll than the state average, but not alarming.
4) Bayou Grande and lower Perdido are clearer than Bayou’s Texar and Chico.
5) All these bodies of water are less than 20‰. More on this as well.
1) We already discussed the phosphorus issue (or non-issue), but what about Bayou Chico? Phosphorus is NOT introduced to the system from the atmosphere as nitrogen is – rather, it comes from the sediments. High levels of TP would suggest high levels of sediments in the water column (the water clarity data supports this) – which suggest high levels of run-off. The watershed for Bayou Chico is highly urbanized and run-off has historically been a problem.
2) Nitrogen can come from many sources, but when numbers get high – many will hypothesize they are most likely from lawn run-off (fertilizers), or sewage (septic leakage, sanitary sewage overflows, animal waste). There are certainly other possibilities, but this is where most resource managers and agencies begin.
3) Elevated chlorophyll indicates elevated primary production. This is not unusual for an estuary. They are known for their high productivity. Bayou Chico seems have more algae than the others. Most probably due to the increase levels of nutrients entering the watershed.
4) Bayou Grande and lower Perdido Bay have better water clarity than Bayou’s Chico and Texar. Though all four bodies of water have significant coastal and watershed development, Bayou’s Chico and Texar and completely developed as well as their “feeder creeks”. Again, indication of a run-off problem.
5) All four bodies of water have several sources of freshwater input as well as stormwater run-off that has contributed to the lower salinities found here. It is possible that the salinities here were less than 20‰ prior to heavy development.
There is a common theme with each of these – stormwater run-off. Rain that historically fell on the land and percolated into the ground water, now flows off impervious surfaces (streets, driveways, parking lots, even buildings) into drainage pipes and discharges into the waterways. This stormwater carries with it much more than just fertilizers and animal waste, it carries pesticides, oil, grease, solid waste, leaf litter, and much more.
How do you reduce stormwater?
Well, there is not much you can do with impervious surfaces now, but the community should consider alternative materials and plans for future development – what we call “Green Infrastructure”. Green roofs, pervious streets and parking lots, there are a lot of methods that have been developed to help reduce this problem.
Another consideration is Florida Friendly Landscaping. This is landscaping with native plants that require little (or no) water and fertilizer. It also includes plants that can slow run-off and capture nutrients before they reach the waterways and methods of trapping run-off onto your property.
If you happen to live along a waterway, you might consider landscaping your property by restoring some of the natural vegetation along the shoreline – what we call a living shoreline. Studies have shown that these coastal plants can remove a significant amount of nitrogen from the run-off of your property as well as reduce coastal erosion and enhance fisheries by providing habitat.
Closed due to bacteria.
Photo: Rick O’Connor
What about sewage issues?
Unfortunately, most septic systems were not designed to remove nitrogen – so leaks occur and will continue. The only options you have there are (a) maintain your septic by pumping once every five years, (b) consider taping into a nearby sewage line.
Sewers systems are not without their problems. Sanitary sewage overflows do occur and can increase nitrogen in waterways. These are usually caused by cracks in old lines (which need to be replaced), are because we flush things down drains that eventually “clog the arties” and cause overflows. Things such as “flushable wipes”, which are flushable – they go down the drains – but they do not breakdown as toilet paper does and clog lines. Cooking grease and oil, and even milk have been known to clog systems.
Our LAKEWATCH volunteers will continue to sample three stations in each of their bodies of water. We are looking for a volunteer to monitor Escambia Bay. If interested contact me.
If you are interested learning more about green infrastructure, Florida Friendly Landscaping, or living shorelines lines contact your county extension office (850-475-5230 for Escambia County). If interested in issues concerning sanitary sewage overflows or septic issues, contact your county extension office, or (if in Escambia or Santa Rosa counties) visit ECUAs FOG website (Fats, Oils, and Grease) https://ecua.fl.gov/live-green/fats-oils-grease.