Improving Water Quality: Part 5 of 5 – Monitoring
In our five part series on improving water quality in Pensacola Bay we have discussed the problems our bay is facing, how you can re-landscape your yard to reduce runoff, how to develop a living shoreline if you are a waterfront property owner, and how boaters and marinas can reduce their impact. The last installment will discuss how and where monitoring is currently going on in the bay.
With the focus on stormwater runoff and the load of nutrients and bacteria it may be carrying, these are the parameters that scientists monitor. In terms of nutrients total nitrogen and phosphorus are monitored. Another indicator of nutrient loads would be the levels of chlorophyll in the water column; and this is often sampled for as well. Factors that may influence the levels of these nutrients and nutrient indicators – such as rain, water temperature, salinity, and dissolved oxygen – are also monitored. Several certified labs monitor the levels of indicators of pathogenic bacteria. Coliform bacteria are typically sampled for in freshwater, and Enterococcus are sampled for in brackish and marine systems. It is important to note that these are NOT pathogenic bacteria but indicators of their possible presence.
The agencies monitoring these parameters include the federal Environmental Protection Agency (EPA), the state Florida Department of Environmental Protection (FDEP), the county health department (ECHD), and even citizen scientists such as the Marine Science Academy at Washington High School (MSA), and the University of Florida / IFAS LAKEWATCH program. The locations and frequency of sampling vary from one agency to another but they do work together so that a larger more efficient effort of monitoring occurs.
Locally the FDEP and ECHD both monitoring weekly and post their results on the following website:
The Sea Grant Agent in the Escambia office logs these values each week. Beginning this week we too will post what the numbers are and give short comments on the state of water quality in the area each week. Here is a look at what has happened so far this year.
The Florida Department of Environmental Protection monitors 20 different locations in the Pensacola Bay watershed. They look at water temperature, salinity, dissolved oxygen (DO), and bacteria. The DO values should be above 4.0 mg/L. With freshwater coliform bacteria a single sample should not have more than 800 colonies / 100ml of sample. For brackish water Enterococcus it should not be more than 104 colonies / 100ml of sample. The Sea Grant program here in Escambia is currently monitoring our three bayous and the lower portion of Perdido Bay for a program we are calling “Bringing Back the Bayous”; so it will be these four that we will focus on here and each week until the project expands.
Below are the average values for the data collected between May and September of 2013.
Location Water temp (°F) Salinity (ppt) DO (mg/L) Enterococcus (colonies / 100ml)
Texar 84 8.3 6.3 5 (high of 127 on Oct 6)
Chico 82 7.4 6.5 115 (high of 310 on Jul 14)
Grande 83 10.9 6.0 64 (high of 340 on Sep 22)
Lower Perdido 82 12.0 5.3 14 (high of 76 on Sep 15)
The lowest DO reading was 4.1 in Bayou Grande on Aug 11; so far DO has not dropped below 4.0 at any location this year. Bacteria counts have risen above the 104 value 5 times. These have occurred in each of the bayous but not in the lower Perdido. Water temperatures have been steadily rising, but that is to be expected with summer. Salinity has been declining but this is due the excessive amount of rain over the summer months. DO has been declining and this can be explained either by the increasing temperatures (which naturally decreases DO), or the nutrient increase due to the rain (see Part 1 of 5 in this series for an explanation of the eutrophication process), or both. The bacteria loads have spiked up and down. These can be associated with the spikes in rainfall. Most of the high values occurred from September 15-22. Health advisories are issued by the ECHD; let’s look at their data.
ECHD records their data using the following rubric:
Good = 0-35 colonies / 100ml
Moderate = 36-104 colonies / 100ml
Poor = 105> colonies / 100ml
These data are totals
Location # of Good # of Moderate # of Poor # of advisories
Texar 22 3 5 8*
Chico 16 3 7 8*
Grande 19 2 7 7
Lower Perdido 22 0 1 1
- The additional advisories were issued because the 30-day average was too high in some cases
The timing of the advisories was interesting:
Jan – 3 (Texar) Jun – 5 total: 2 (Texar), 1 (Chico), 1 (Grande), 1 (Perdido)
Feb – 0 Jul – 7 total: 2 (Texar), 3 (Chico), 2 (Grande)
Mar – 2 (Chico) Aug – 5 total: 1 (Texar), 2 (Chico), 2 (Grande)
Apr – 0 Sep – 2 (Grande)
May – 0
The heavy activity in the summer can be associated with the heavy rainfall we received. Again, Florida Friendly Landscaped yards and Living Shorelines – though they will not eliminate the problem – can reduce some stormwater runoff which trigger these events.
Beginning next week we will post the values from these four bodies of water and give comments. If you are interested in the specific data or other bodies of water you can visit the website listed above and find more. If you have any questions or comments please contact me here at the extension office at 850-475-5230 or firstname.lastname@example.org.