LTC 321-2015 10th Street Bayfront Water Quality Update MIAMI BEACH
OFFICE OF THE CITY MANAGER
NO. LTC# 321°2015 LETTER TO COMMISSION
TO: Mayor Philip Levine and Members of he City Commi i- on
1
FROM: Jimmy L. Morales, City Manager - - -
DATE: August 12, 2015
SUBJECT: 10th Street Bayfront Water Quality Ups ate
The purpose of this Letter to Commission is to provide an update on City staffs activities
regarding the water quality adjacent to the 10th Street bayfront.
Last week the City received concerns regarding the presence of a plume in the vicinity of the
10th Street bayfront. Since then, City staff has been conducting daily visual inspections and has
deployed divers in the water to assess the conditions in the area. Furthermore, we retained an
environmental services firm that collected surface water quality samples on August 4, 2015.
Turbidity samples collected from a sediment plume identified during visual inspections showed
elevated levels of turbidity. We have identified that the plume is caused by the velocity of
pumped water at a nearby outfall, which stirs up sediments in the bay bottom much like a boat
propeller. As such, we have installed a turbidity curtain around the outfalls to limit the extent of
the plume until a more permanent solution can be identified.
Samples collected from inside the plume were also analyzed for Total Recoverable Petroleum
Hydrocarbons and compared to the results of a background sample taken approximately 1,500
feet south of the plume. The results from this analysis did not show elevated concentrations of
petroleum hydrocarbons. To date, the only items that have been documented coming out of the
outfall are leaf litter and a few small plastic bags.
Today the City received reports of a sheen at the site. I, along with City staff, including Assistant
City Manager Mark Taxis, City Engineer Bruce Mowry and Environmental Manager Margarita
Wells, inspected the area from land and from the water. Representatives from the
Environmental Protection Agency, who were onsite, confirmed that the minimal sheen was not a
cause for concern. The U.S. Coast Guard and Miami-Dade County were also present and
issued no violations.
We take the condition of our waterways very seriously and have a multi-facetted stormwater
management program in place to minimize stormwater pollution. The first component of this
program focuses on preventing pollutants from entering our stormwater system through public
education, daily street sweeping, and other good housekeeping practices. The second
component of this program focuses on trapping debris within the system and removing it from
the stormwater via Vortex structures and other pollution control structures. The third component
of the program focuses on regular cleaning and maintenance of our stormwater structures to
remove pollutants from our system. It is our goal to clean the entire system at least once per
year, ant the Vortex structures at least quarterly.
LTC—10th Street Water Quality
August 12, 2015
Page 2 of 2
It is important to recognize that the pumped system continues to only discharge stormwater, as
the gravity system has for 100 years. Our stormwater system is not discharging anything new.
On the contrary, the pumped discharges are cleaner than the ones from the gravity system
because they are filtered before reaching the bay as evidenced in our latest MBTV segment:
https://youtu.be/wHdRn PF6V8. These enhancements, in conjunction with our comprehensive
stormwater management program, help us improve and preserve the quality of our waterways
and vital marine resources.
If you have any questions, please feel free to call me.
MT/ETC/MKW
F:\WORK\$ALL\(1)EMPLOYEE FOLDERS\BETSY WHEATON\LTC\10thth Street Water Quality Update-LTC 8.12.15.docx