Jacksonville Harbor Deepening:
A Never Ending Saga
Quinton White, Jr., Ph.D.
Professor of Biology and Marine Science
Executive Director,
Marine Science Research Institute
Jacksonville University
St. Johns River – Mouth to Jacksonville - 1791
Jacksonville Harbor Channel
Improvements – First Dredging
• Dredging of the 6 mile long channel
commenced in June 1892 and took exactly
two years.
• The 15 foot deep channel permitted ships
drawing 20 feet to dock in Jacksonville.
• Prior to project completion, discussion about
additional deepening commenced.
Jacksonville Harbor Channel
Improvements – Deepening
• After 6 years of deliberation (1902)Congress made an
initial appropriation of $350,000 to start the dredging
of a channel 24 feet deep and 300 feet wide, from
Jacksonville to the sea.
• By 1906 the work was completed and the 24-foot
channel became a reality.
• Ten years later, in 1916, another dredging project was
started that resulted in a 30-foot channel from
Jacksonville to the sea.
• By 1924 ships weighted to 30 feet could dock at the
municipal docks in Jacksonville at low tide.
• Total cost of dredging and jetties: $7 million
Port of Jacksonville Project and
Channel Improvements
• 1880 – June; Jetties at entrance (maintenance only)
• 1890 –Two jetties on Volusia Bar and 6’ deep channel
• 1892- Secure 15’ deep navigational channel Dames Pt (RM 11) to Mile
Point (RM 5) - Completed 1894
• 1896 – 24’ Jacksonville to Ocean & extend jetties - completed 1906
• 1910 – 30’ Jacksonville to Ocean – completed in 1916
• 1925 – The distance from the mouth to the FEC RR Bridge is 28.1 miles
• 1930 - Widen bend at Dames Point to 900’
• 1935 - Widen Trout, Six Mile and Drummond creeks
• 1945 – The river channel deepened to 34’ and the Dames Pt. Fulton Cut
made – Federal Project 26.8 miles long.
• 1965 – 38’ deepening completed in 1978
• 1998-2004 – RM 15 to mouth of the SJR deepened to 40’
• 2010 – Drummond Pt. to Tallyrand (5.3 mi) from 38 to 40’
St. Johns River Dredging at Dames Point
1918
St. Johns River Dredging Impacts:
• Impact to benthic (bottom dwelling)
organisms
•Impact to salinity zones
•Impact to marine mammals
• Impact to flushing rates ( positive and
negative)
•Impacts to tributaries (positive and
negative)
Table 33: Summary of Direct and Indirect Impacts
ALTERNATIVE
ENVIRONMENTAL
FACTOR
44-ft Deep
Channel
45-ft Deep
Channel
46-ft Deep
Channel
47-ft Deep
Channel
50-ft Deep
Channel
No Action Status
Quo
GENERAL
CONSEQUENCES
(refer to Section 7.1.1)
Larger ships and
increased
ship transits are
predicted.
Deepening would
result in predicted or
anticipated
increases in salinity,
tidal amplitude,
stress levels on
aquatic plants, risk
to threatened and
endangered
species, air
pollution, and water
residence time.
Larger ships and
increased
ship transits are
predicted.
Deepening would
result in predicted or
anticipated
increases in salinity,
tidal amplitude,
stress levels on
aquatic plants, risk
to threatened and
endangered
species, air
pollution, and water
residence time.
Larger ships and
increased
ship transits are
predicted.
Deepening would
result in predicted or
anticipated
increases in salinity,
tidal amplitude,
stress levels on
aquatic plants, risk
to threatened and
endangered
species, air
pollution, and water
residence time.
Larger ships and
increased
ship transits are
predicted.
Deepening would
result in predicted or
anticipated
increases in salinity,
tidal amplitude,
stress levels on
aquatic plants, risk
to threatened and
endangered
species, air
pollution, and water
residence time.
Larger ships and
increased
ship transits are
predicted.
Deepening would
result in predicted or
anticipated
increases in salinity,
tidal amplitude,
stress levels on
aquatic plants, risk
to threatened and
endangered
species, air
pollution, and water
residence time.
An even greater
increase in
ship transits is
predicted. This may
result in increased
risk to threatened
and endangered
species and air
pollution. Other
factors (i.e. sea level
rise, variable rainfall
levels) would affect
salinity, tidal
amplitude and stress
levels on aquatic
plants.
Generally slight
changes in physical
and water quality
conditions.
However, changes
may be greater in
specific areas.
Salinity change may
modify biological
communities (i.e.
wetlands,
submerged aquatic
vegetation, and
fauna).
Phytoplankton
dynamics may
slightly change.
No effect. (Other
factors such as sea
level rise and
variable rainfall
would affect salinity
levels and may also
modify biological
communities.)
GENERAL
ENVIRONMENTAL
CONSEQUENCES
(refer to Section
7.3.1)
Generally slight
changes in physical
and water quality
conditions.
However, changes
may be greater in
specific areas.
Salinity change may
modify biological
communities (i.e.
wetlands,
submerged aquatic
vegetation, and
fauna).
Phytoplankton
dynamics may
slightly change.
Generally slight
changes in physical
and water quality
conditions.
However, changes
may be greater in
specific areas.
Salinity change may
modify biological
communities (i.e.
wetlands,
submerged aquatic
vegetation, and
fauna).
Phytoplankton
dynamics may
slightly change.
Generally slight
changes in physical
and water quality
conditions.
However, changes
may be greater in
specific areas.
Salinity change may
modify biological
communities (i.e.
wetlands,
submerged aquatic
vegetation, and
fauna).
Phytoplankton
dynamics may
slightly change.
Generally slight
changes in physical
and water quality
conditions.
However, changes
may be greater in
specific areas.
Salinity change may
modify biological
communities (i.e.
wetlands,
submerged aquatic
vegetation, and
fauna).
Phytoplankton
dynamics may
slightly change.
WATER QUALITYSALINITY (refer to
Section 7.2.6.1
and Appendices A
and D)
Increases in depth
averaged salinity
(≤ 0.7 ppt) are
predicted in
certain areas
(refer to Table
46).
No data available.
Increases in depth
averaged salinity
(≤ 0.8 ppt) are
predicted in
certain areas
(refer to Table
46).
No data available.
Increases in depth
averaged salinity
(≤ 0.9 ppt) are
predicted in
certain areas
(refer to Table
46).
No effect.
(However, other
factors such as sea
level rise and
rainfall variability
would affect
salinity).
WETLANDS (refer
to Section 7.3.9
and Appendices D,
E, F, G)
Dredging
operations would
not directly affect
wetlands.
Predicted indirect
effects due to
salinity change
would impact an
estimated 448.95
acres of wetlands.
Mitigation and
monitoring would
be performed.
Dredging
operations would
not directly affect
wetlands.
Predicted indirect
effects due to
salinity change
would impact an
estimated 448.95
acres of wetlands.
Mitigation and
monitoring would
be performed.
Dredging
operations would
not directly affect
wetlands.
Predicted indirect
effects due to
salinity change
would impact an
estimated 448.95
acres of wetlands.
Mitigation and
monitoring would
be performed.
Dredging
operations would
not directly affect
wetlands.
Predicted indirect
effects due to
salinity change
would impact an
estimated 448.95
acres of wetlands.
Mitigation and
monitoring would
be performed.
Dredging
operations would
not directly affect
wetlands.
Predicted indirect
effects due to
salinity change
would impact an
estimated 448.95
acres of wetlands.
Mitigation and
monitoring would
be performed.
No effect.
(However, other
factors such as sea
level rise and
variable rainfall
would affect
salinity levels and
may also modify
wetland
communities.)
SUBMERGED
AQUATIC
VEGETATION
(SAV) (refer to
Section 7.3.10 and
Appendices D, E, F,
G)
Dredging
operations would
not directly affect
SAV. Predicted
indirect effects
due to salinity
change would
impact an
estimated 296.60
acres of SAV.
Mitigation and
monitoring would
be performed.
Dredging
operations would
not directly affect
SAV. Predicted
indirect effects
due to salinity
change would
impact an
estimated 296.60
acres of SAV.
Mitigation and
monitoring would
be performed.
Dredging
operations would
not directly affect
SAV. Predicted
indirect effects
due to salinity
change would
impact an
estimated 296.60
acres of SAV.
Mitigation and
monitoring would
be performed.
Dredging
operations would
not directly affect
SAV. Predicted
indirect effects
due to salinity
change would
impact an
estimated 296.60
acres of SAV.
Mitigation and
monitoring would
be performed.
Dredging
operations would
not directly affect
SAV. Predicted
indirect effects
due to salinity
change would
impact an
estimated 296.60
acres of SAV.
Mitigation and
monitoring would
be performed.
No effect.
(However, other
factors such as sea
level rise and
variable rainfall
would affect
salinity levels and
may also modify
SAV communities.
Mitigation
• Very Difficult to Mitigate Salinity Changes
• Corps had proposed to increase monitoring
– The proposed monitoring has no mechanism to react if
damage is discovered.
– Monitoring is not Mitigation
• Purchase of Credits from Wetland Mitigation Banks
• Funding Nutrient Reductions that are already existing
regulatory requirements
• Restoration of the Ocklawaha River (removal/breaching
of the Rodman Dam) has been withdrawn as an option
The Billion Dollar Question:
Is it worth it economically for the
environmental damage that will occur?
And is there a better way to achieve
the same end result?