Comments submitted as part of this
meeting will not be considered
formal comments on the project.
Formal comments must be submitted online
or postmarked by September 12th, 2022,
and we will be showing the website later.
It's our park planning website, Pepsi.
And there is a slide that
describes how to ask a question.
Click on the chat icon.
The media the chat panel will open on
the right side and you can enter your
question into the box and select send.
So we've covered introductions
for the park and I will turn
it over to once again to the.
Any firm who's running the project?
So can't. I don't know if you're on Umm,
but I'm Kim gay leader.
I'm the project manager for H traceries.
Laura Hughes, our principal is on as well,
where we handing the Section
106 for this project?
The AE team is is quite a large team,
so I'll let people run through who is on.
I know that Margaret is on.
From Moffett nickel.
And Kim, this is Kim, Roger,
I'm the program manager for the
HDR Moffitt Nickel joint venture
serving the park with this program.
Check on the coastal
engineer with the JB program.
And Doug, I don't know if
you're on for interagency,
but he is handling the nipa.
I am. Good morning, everybody.
And Annapolis landscape SCAPE
architects Shelly is handling
the landscape arm of the project.
So we kind of skipped over this,
but the agenda here is really
just talking about the project,
undertaking a brief history of the seawall,
the existing conditions and how we've
gotten to the point that we are at an
overview of the Section 106 process,
identifying the historic resources
and then really getting into the
meat of what the preliminary.
Concepts will be and then at the end
discussion questions and comments.
So I'm going to turn it back to
Catherine to discuss the project
undertaking from the parks perspective.
Let's go ahead.
And before we do that,
we'll introduce some of our
consulting parties, DC SHIPPO,
CFIA and NCPC,
in particular the agencies.
So I see Andrew Lewis and David
Maloney from the DC Shippo,
and I'll turn it over to NCPC and
they can introduce themselves.
But. Good morning, everyone.
This is Lee Webb with NCPC. Thank you.
And Tom, hi. Yeah, this is Tom.
Luke with the Commissioner of
Fine Arts and I've got two
other members of my staff here.
Great. Thank you. Should I should I tell?
Oh, sorry. I guess you're gonna
say Sarah Batchelor and Dan Fox.
I guess I'll just say it for them.
Thank you. Great. Thank you.
So the project undertaking is to
rehabilitate approximately 6800 feet of
seawall in the tidal basin to what we're
calling the historic functional fight.
Excuse me. Height.
It's the seawall has deteriorated.
We have a lot of flooding.
For the most part, the land has settled.
And then we also are dealing
with the sea level rise.
So we have flooding.
Our cherry trees are being damaged
and the landscape is being.
Umm.
Harmed.
So this shows the project area.
Most of the significant flooding
happens around the tidal basin just
to the West of the Jefferson Memorial.
Then we have we do have
some flooding along the.
West Potomac seawall.
Which extends along the
West side of the park.
So, and I'll turn it over to Kim
for the history of the seawall.
OK, so I think we all are familiar
that this land is reclaimed land
and was not historically there.
It wasn't ever part of Lafonte plan.
We can see here his map from 1791.
However, in the mid to late 19th century,
sanitary flood control and river
navigation all started to become an issue.
And so as early as the 1860s really they
there were discussions to dredge the Potomac.
River and to create reclamation lands.
So really this was part of kind
of the city beautiful movement,
controlling the way that
they controlled sewage.
You know, it started creating swamps.
As we all know historically DC is being
called that and so they actually had
already started reclaiming about 160 acres
around Longbridge as early as the 1860s.
So by the 1870s,
the Army Corps had formally started
dredging for the shipping channels,
and we can see here in the saxxy map that
it is actually the Potomac Flats are
already outlined by the 18 mid 1870s.
They decided to not only just make the flats,
but then to close the land
up on the Upper West Side.
And while the layout continually changed,
the first person to talk about
title basins was major twinning,
and he proposed that in 1879.
And though the design went through many,
many iterations,
we see here a satsky map from 1901.
You know,
the dredging was ongoing
between the 1880s and 1890s.
They dredged more than 12
million cubic yards and claimed
600 acres of land and by 1897.
That was declared to become
a public park for the people,
so we can see here the 1896 progress
map from the Army Corps of Engineer.
And it's really the first time
you see formally what we now know
as the tidal basin taking shape.
Other reservoirs and ponds were still.
You know on the plan,
but it's really the first time we
see that tidal basin as we know
it to be taken shape.
Umm,
so how they really built the walls
was they first cut through with
stone footings and trenches and
then they backfilled and embankment
with the stone footing.
And then once the land was filled
up to a point,
they formally finished the walls.
So the walls were kind of ongoing
throughout the dredging process.
We can see here on the right,
a cross section from NPS in the 1940s
showing the original design of the
wall and the stone walls were six feet high,
4 feet.
Like at the base with two
and a half thick top.
So really, as Catherine said,
we have 4 distinct sections
sections in this process.
We have West Potomac Park to the North
West Potomac Park, SW, Tidal Basin,
East east and Tidal Basin West,
and they're really four different
distinct sections because of the way the
walls that are existing right now were
constructed or their existing conditions.
So if we start with Tidal Basin and East,
this section of this wall was actually
rebuilt in the 1930s for the Jefferson.
Memorial the tidal Basin actually
was reshaped in order to fit the
memorial at its existing location,
so a new seawall alignment
in the 1940s was put in,
and then the only other major
change was that in the 19th in 1942,
a railing was put around the tidal basin
and and that was taken off at one point.
But we can see here what
this section looks existing.
It's not in very good shape,
but this is a picture of the
cross section of the 1940s.
Design of the wall.
And here is a construction photo.
You can see they're reclaiming
where the original title basin was,
and this is the alignment of the new Wall,
the Jefferson Memorial,
being over here.
And here is another progress shot of
this section of the wall being built in,
and I highlight this one only because
here you really get to see that ashlar
pattern of the Potomac River stone
being laid and how high the wall was.
So for a little bit of a different section,
the tidal basin wall to the West
was actually rebuilt in 1909 when
the inlet bridge here was put in.
So this wall dates to 1909 and 1941.
A seawall concrete coping that's 8
inches thick, was put on top of it.
That's the sidewalk that we see now.
Next to the Roosevelt Memorial and
again a railing was put on in 1942
and taken off at an unknown date.
So here is this cap.
That was put on the wall,
but this is a a section from the Clr that
shows how the title basin walls were built.
They're designed in 1907 but.
Put inserted in 1909 when they
put in that inlet bridge.
So West Potomac Park South is
actually the location of the oldest
persons of the wall that we have
remaining in this project area.
The foundations were completed in 1884 and
they were topped off at 1890 eighteen 91.
However,
materials due to the wall sinking
have continuously been put on top
of this wall and rip wrap have
been added as late as the 1990s.
So West Potomac Park North was
actually completely rebuilt in
1957 by Pepco for power lines that
were running underneath the river.
So we are unclear as to how much of
this wall the historic foundations
remain underneath.
But you can see here from this
cross section that a basically a
solid concrete cap was built right
on top of what was the Stonewall.
So we don't really know exactly
until we get into the project how far
down that goes and how much of the.
Historic Stone is still there.
So I'm going to pass it over to
Margaret to discuss a little bit more
about the existing conditions and how
we've gotten to the point where we are now.
Thank you, Kim.
So we'll go look at some of the
pictures from the existing conditions.
If you can move ahead, great.
So this is showing a flood
event that happens often,
this one particularly bad because
it is over the walkway of what
you're seeing on the West side.
I'm sorry, the West,
the left side of the screen is
your east tidal basin photographs.
This is a flood event that
happens about once a month.
You can see that you can't
even discern where the.
The seawall is,
and that water actually extends pretty
far inside the this flat grassy area.
In fact,
the ADA walkway that was installed
to to allow mobility through this
area due to the floods along the
seawall is is even overtopped,
so mobility is restricted in this area.
Now on the right side of the screen,
the top you're you're seeing
the connection of West Potomac.
I'm sorry, title basin.
West the connection between the
inlet bridge and the seawall.
You can see that's starting to pull away,
and in fact,
the backside of that CAP is starting to sink.
This suggests a a good amount of of
soil and material is being pulled
through that wall or around those
those openings and the bottom right
side photo is from West Potomac South.
As Kim was saying this,
this wall was overtopped and
eroded and has fallen forward.
So what you're seeing in
that photo is a lot of the.
Chip wrap and that irregular
shoreline due to the erosion.
But the stones from the existing arm.
Sorry.
The original wall are actually
submerged and still somewhat in place.
And the next slide shows a bit
more of that deterioration.
The wall,
the largest photo on the right
is a section of the CAP in title
Basin East and you can see that
eroding away that could be due
to poor construction practices at
that time or even the brackish
water causing spalling and and
just that aggregate to break apart,
which creates an unsafe edge on the
left side of this of this slide.
Top corner.
That is the connection point
between the West Potomac North
and the West Potomac South.
As Kim mentioned that North section
was manipulated in the late 1950s
and elevated with a A concrete cap,
you can see that that did not continue,
but a lot of that rip wrap is
is shown in the front front of
that screen which is foreign to
the original design.
And then finally on the left bottom
we see the roots of the cherry trees.
Starting to become exposed due
to the frequent inundation of
the uplands in this location,
it is flooded almost daily,
if not more,
two times a day due to the higher
water levels and the settlement of this area.
This particular tree is actually
in Tidal Basin east and the
frequent washing of those those
routes has completely eroded
away the vegetation and hinders
the growth of those trees.
Which are are damaged due to that
brackish water. Next slide. OK.
The largest picture on the left is the
southern end of West Potomac South.
You can see just along the waters
edge that original gravity
Stonewall of that Potomac stone.
Nice slab, flat pieces with the
Rip wrap place behind it to
prevent the erosion of the uplands.
This is a lower tide picture because
frequently that wall is overtopped as well.
At high high water level.
And then on the right side or
two more from that southern end.
Actually, right around that corner of
the the southern side of West Potomac South,
where currents and frequent washing has
actually continued to erode to that section.
But the alignment is still recognizable
from a few remaining stones that
are are still in place from that
original construction.
Can. OK. And a couple more on the left side.
We're seeing West Potomac Park
once again on the South side,
this is a low water image on the the top.
So you can see that wall placed
further out with the rip wrap.
And on the southern,
I'm sorry on the bottom picture,
you can even see some asphalt.
There's a good amount of foreign
material that has been thrown into
this area to hinder that erosion
and to hold that wall together,
it has not done a good job.
So we are planning on removing all of that.
More material and reestablishing
that wall as it was intended to be,
and on the the right is a
little bit of a comical photo.
This gentleman was trying to to
drive through or pedal through the
floodwaters on Tidal Basin West while
we happen to be there performing a
site visit and you can imagine this
is not a really terrible flood event.
Actually this is on the lower end
so it it gets worse than this.
Regularly I should point out.
And next slide.
And I'll pass it back over to Kim again,
I believe.
Yep, thank you Margaret.
Umm,
so I won't really believe her these
slides because I think everyone here
is familiar with the 106 process.
But we do have federal agencies due to
the National Crystal Preservation Act,
must consider the direct and
indirect effects of a proposed
undertaking on historic properties.
And we have consulted with Sipos and
tribes and you all as the consulting
parties as this project is underway,
I will share with you the draft.
Area of potential effect and you know the
identified historic resources within it.
So consulting party involvement,
I believe you're all familiar.
It's shippo's tribes,
local governments,
the Advisory Council and any other
organization or advocacy group that has
an invested interest in the historic
properties and how they are affected.
And So what we're asking for
you all to do is help us,
you know,
identify historic properties if I have.
This one,
please let me know review the
information that we provide you
and help us consider ways to avoid,
minimize and mitigate any adverse
effects to those historic properties.
So the consulting parties we all went
through and introduced ourselves,
but these are some of the parties
that were invited today.
I'm sure you're all familiar with each
other and then this is just a very
brief 4 step consulting party process.
We're in Step 2.
Right now of identifying potentially
historic properties that could
be affected by this undertaking
and the next step would be to
assess any potential adverse
effects from the undertaking.
We are doing a coordinated nipa
and 106 approach for this project.
Currently the in NEPA,
we are in the middle of the public
scoping period and here we have
the first section 106 meeting.
Of course,
the next steps will be to analyze
the alternatives and to develop
the EA and and the NEEPA
documents to determine any
adverse effects on the resources.
So for the identification
of historic properties,
we have here the add area
of potential effect.
We did stretch it across the river
so that any visual impacts to
Mount Vernon Memorial Highway and
George Washington Memorial Park or
Arlington National Cemetery could
take be taken into account due to the
drastic the changes in the heights
of the seawalls were turning it back
to its historic functional height.
Other resources.
In the ape are,
of course the Washington Monument
and grounds East and West Potomac
Parks and the National Mall.
So just to go over those
properties within the APEC,
we have East and West Potomac
Parks that was listed in 1973 and
contributing resources to that
park are of course the stone walls
and our beloved cherry trees that
are in danger with all of this
flooding for the National Mall in
Washington Monument and grounds.
Again, the title basin,
wall and walls and cherry trees
are all contributing.
Resources to these historic
districts and the National Mall
was expanded in 2016.
And just to point out,
the period of significance for this
resource is actually up to present.
So it's just important to keep that
in mind when you're dealing with
a resource that it has kind of an
open ended period of significance.
The George Washington Memorial Parkway
and Mount Vernon Memorial Hwy are
directly across the river from the
location where we'll be doing work
on the West Potomac Park walls,
so we must consider impacts
to those resources.
They was one of the first park
projects and GWP, of course,
was part of the Macmillan Commission
proposed in 1902 and part of the
intention of the design was to frame
views to the monuments across the river.
Arlington National Cemetery and,
of course, Arlington Bridge,
where our project area
actually ends right here,
where the 1957 wall hits the Memorial Bridge.
So you know, of course,
Memorial Bridge design.
McKinney and white,
very significant building and
just went under a huge renovation.
So we want to make sure that there
would be no adverse effects to this
beautifully restored historic resource.
And then of course we have the
memorials within the parks themselves.
MLK, Franklin Delano Roosevelt and
Thomas Jefferson are all within
the APEC and adverse effects to
those memorials will certainly
be taken into consideration.
Umm.
So I'm gonna turn it back over to
Margaret to discuss the permanent
preliminary concepts for the project.
Thank you, Kim.
So the next slide gives us an idea
of one of our initial concepts.
We should mention that there are
four guiding principles when we're
looking at concepts we we want to
maintain the historical alignment,
the historical look with the stacked stone.
The we want to prevent any future settlement.
One thing that Kim mentioned early
on is this whole area was developed
from alluvial soils from dredging
operations and those consolidate.
Overtime,
which has caused settlement of West Potomac,
East Potomac and all of the
tidal basin at varying levels.
So we want to prevent that settlement
by including including a foundation
that extends all the way to bedrock
and the last guiding principle is
the upland and the vegetation and the
landscape to maintain that visitor
experience with the flowering Japanese.
Cherry blossoms and such.
So this is our cross section based on I
guess those first three guiding principles.
We have a micro piled.
A platform that is going to support
to then a wall which will still
have that historical look but have
modern engineering techniques.
We it does include removing the
existing wall in its entirety.
The foundation can remain,
but once put back the look of it
will will be just in line with that,
that historic understanding,
this relieving platform that is
going to be founded into bedrock
will also support any walkway.
Or lands on the Lee side of that wall.
So going to the next slide.
This is a slightly different option,
but the same idea.
This is for that West Potomac North.
This is one of the alternatives that we
are considering that wall being replaced.
I'm should should say rehabilitated
by PepsiCo in the 1950s is
in very good condition.
So we are looking at utilizing
the existing wall and just adding
to it to increase the height.
So Speaking of height,
we can go to the next slide.
We are looking at establishing a,
reestablishing the historic functional
height and I'll get to that in a second.
But what we're looking at on this
graphic is water level events
and high water level events by
average annual hours of exceedance.
The blue line is what we see currently,
and that's based from 1995 to 2021.
And we see that comment events
range all the way up to.
3.75 Now common events being 15 average
annual hours of exceedance per year.
Rare storm events do push
that water level even higher.
These are your larger storm surges,
rain events, hurricanes,
things in in that order that we also
understand that in the future there
is sea level rise in climate change.
So forecasting based on our our best
understanding of of how the climate
is changing within the DC area.
We have that dashed orange line
which shows that future common
flood events will actually increase
and that pushes those rare storm
events even higher as well.
Now a historic functional elevation.
It was based on a 6 foot high
wall above mean tide level,
which is about mean sea level and
looking at today's water levels
that would put us around 4.75.
Now you see 4.75 is just outside
of those future common.
Blood events,
but one thing I should also mention is
the height of the existing wall ranges,
anywhere from zero to about 3 feet.
So we are looking at raising
that wall a a good amount.
Now 4.75 does not provides us a lot
of future flood protection and is
not a huge impact on on the site.
When we start looking at raising that water.
I'm sorry that that seawall elevation,
and therefore we are looking at
raising all the seawalls everywhere
to a minimum of 4.75.
Moving to the next slide.
So this is what it looks
like in graphic form.
We have our title basin East,
which is our lowest section,
which varies from zero point 4 to about 2.5.
And we've put a human on there for for
some scale and that proposed wall height,
elevation of 4.75.
The next slide shows what that's going
to look like once it's raised with this
concept that we are currently looking at,
we are looking at sheet flow on
the backside for any kind of.
Stormwater.
So therefore you see the existing
grade on the Lee side of that
wall being raised as well.
This will impact some of the trees
and therefore those trees will will
need to be replaced or protected
depending on their level of impact.
Tidal Basin east requires the most
amount of of fill on the backside tidal
Basin West I believe is the next slide.
You can see the existing grade
actually elevates rather quickly
behind the the seawall and therefore.
Once we raise that wall,
which is the next slide,
the the amount of fill on the backside
to maintain that sheet flow has a
much smaller area of impact before
it marries into the existing grade.
Next slide is the title,
I'm sorry, West Potomac South,
this is where we're essentially
rebuilding the the complete wall.
Now there's elevation of the the land side
also raises pretty quickly and therefore.
Uh,
the impact to the upland is also minimized
as it marries into the existing grade,
which is the next slide.
There you can see it there.
Now one thing I do want to also point
out on this slide is proposed wall
height ranges from 4.75 to 5.5 during
our analysis of the Potomac River,
we recognize that there are
additional forcings such as waves,
ice,
current boat wake that is just not
present or at least not in such a
large capacity within the tidal basin.
Ergo,
raising that wall height higher will provide.
Provide additional protections
now in into the future,
and then the final section
is that West Potomac North.
This would also then be increased
to the up to the 5.5,
though this wall is in very good condition,
there are some low points that
go down to about 1.1,
so we'd be looking to raise that
over 3 1/2 feet and the next
slide shows how that would look.
Next slide.
OK. It's the next slide.
And they're also in this area,
the water level, I'm sorry,
the land side does raise as well.
So the marrying into the existing
grade is causes a less distance
of impact into the upland.
Kim, I think that's the last of my sections.
Him.
Catherine, can you hear me?
I can hear you. OK, we we might
have a problem with the uh Kim's
computer might have frozen up.
It looks like she just left.
Do you have a copy, Catherine?
To that you can share of the presentation.
It just got it opened.
Not a big meeting without
one or two technical issues.
I'm just trying to get it
down to where we were. Sure.
We were toward the end.
I should be slide 50 about yes.
That's when I can also
share if you need me to.
Perfect. Thank you.
So that that is the visual.
What that looks like?
You got kicked out.
OK. I guess we can go to the next slide.
All right, now is the time
for any discussion, any,
any comments, any questions or we
can talk through any concerns.
And you don't have to type
in the chat for this.
Yeah, if you want to raise your hand,
I'm Manning monitoring that for Catherine.
Kamloop key.
Yeah. I just. Uh. This seems oops,
I'm picking the wrong box here.
It seems like it's
incredibly straightforward.
If so, let me just make sure I understand it.
You're you're taking the same
plan alignment you are elevating?
Generally this.
This retaining wall or whatever you
want to call bulkhead wall such that it is.
More to its historic height relative to the
to whatever the current mean water level is,
which is going to be about 4.75 generally.
And so, so and then you've got these
various engineering solutions for
various conditions and segments.
The biggest impact seems to be what do
you have to do to to get the right?
Positive slope back down to the
edge or you're going to flatten
the uplands a little bit.
You're going to get.
You're going to have to move or elevate,
or somehow there's some tree impacts
generally, but that seems to be.
Am I right? I mean, there's not a lot to.
There's not a lot of change in plan.
It's literally it's mostly just a
question of section and when you
elevate that bulkhead and you just
sort of you flatten the backfill,
that's literally where where we kind
of have to contend with the impacts.
Is that correct?
I believe that is correct, yes.
It is a very straightforward.
Yeah, it's very expensive project,
but it's a very straightforward project.
Seems like a very sensible way to do it.
I mean, I don't.
I don't know what you do about the trees,
and it's a little hard to.
That's something where you would
have to kind of. Map it out.
How much which trees can be saved and how
much have to be either removed or lifted,
or I don't know what you have to do.
Anyway that seems to be the issue.
Yes.
And some of the trees,
particularly along Tidal Basin
East are basically twigs out of
the ground from the brackish water.
Suffering. Yeah.
OK.
And so and and otherwise the
one question I had is the,
the,
the top you're going to use the the larger
scale stone on the on the vertical faces,
the battered faces of the of the
bulkhead and the top is generally,
is that going to be concrete
or granite slabs?
I can't remember what is it generally?
Concrete right now.
For the for the sidewalk.
Alright, I don't really have
any other questions. Thanks.
I want to mention you
brought up a good point.
We are elevating this area.
One thing about the area next to the
Thomas Jefferson Memorial on the West side,
which we call title base in the
east that Upland has settled as well
when it was created, it just wasn't
didn't have enough compaction at that time.
And so the upland has settled and
therefore we're reestablishing
that historic upland as part
of this project as well.
Andy.
Yeah. Thank you. Can you hear me?
Yes. OK. Yeah. Thanks for.
I wanted to say I appreciate that you
started off with a A history of the sea
walls and how the various sections were
constructed over time and it it sort
of raised the question about how much
difference there is in terms of the
appearance of each individual section.
And how what what the what the the options
that the Park Service is considering
how it's going to address that.
For example there was a coping that was
placed on later in one section of the wall,
another sections.
There isn't a coping and essentially
what I'm trying to get at is is
evaluating what are the effects on
the historic resources in terms of
how much each section is going to
be altered like is this is the idea
to create a single appearance that
would be used in all four sections.
Or are you trying to respond to the
appearance and the construction methods
that were used in each individual section?
Or have you really given that a lot
of thought yet and just just wanted
to try to see what your thoughts
are at at this point on that topic?
I don't think we've given it a
lot of thought at this point,
but I'll let Margaret speak to that.
She's intimately familiar with.
The existing conditions?
Absolutely.
So the the three sections, West Potomac,
South and both of the title basin
sections have the Potomac River stone
that's plus placed in in a I think
Kim called it an Asher stairstep.
Look, it is historic.
It is very particular to those sites.
We plan on maintaining those the
walkways that are along the tidal basin.
We plan on replacing those
with concrete walkways.
The proposed walkway right
now is 18 feet wide,
so this is actually an improvement on
the more narrow walkways that are there.
The West Potomac does not have a a walkway,
and at this point we are intending
for it to remain as grass,
though that that may change at some point.
The the look of the walls themselves is
going to maintain that Potomac River stone.
Now the one area I did not
mention was West Potomac.
North when PepsiCo redid that location,
they did put a concrete cap and it's
either a stone or a stone facade type.
Look along the front face of that.
Now that wall, because of its age,
is now historic in its own right,
but it does not maintain that
same Potomac River stone.
Asher.
Pattern look so it is slightly
different there.
Now the only way you can see
that and the only way we can see
that is from the river itself.
What is inside the tidal basin and
what is visible from the inlet bridge
will be that Potomac River Stone,
which is so classic to this area.
OK,
so you are you are planning to
try to respond to the existing
conditions in each section.
It sounds like to the extent
that that's possible.
So yeah, it would be helpful if
we could have some photographs
just to get a good sense of what
the four individual sections
look like in terms of you know,
so we could judge the difference
in in their appearance and and
maybe have a better idea of of
what should be done in each in each
section recognizing that you know
the whole thing is in some sections
is going to be completely new.
But trying to respond to the
historic conditions could be a way.
To to maybe minimize any adverse
effects that result from the project.
So thank you for that information.
Absolutely. So to your point,
we are taking photographs from the
water at low tide of all of these
walls and our job internally is
is going to be to establish the
criteria to which the contractor
will need to redesign,
redevelop these walls in that historic look.
So we will have a better understanding of.
Of each walls individual characteristics.
Great.
Thank you.
And Sarah?
Hi, yes, thank you. I I agree that I think
you're doing a good job with minimizing
the apparent impact of the project
on which obviously is clearly needed.
And well, the biggest impact seems
to be on the trees. So we'll see.
You know your plans for that as we go along.
I just had two questions.
One is just to clarify.
You had said that the the height of
the wall when it was constructed.
I said six feet above mean high watermark.
I guess if I've got that right.
And am I correct that you are? Umm.
Proposing to go 4.75 to five and
a half feet above mean watermark.
In other words,
you're proposing that the visible
height of the wall would be slightly
less than it was originally.
Or am I just misunderstanding that?
That's quite sorry.
Let me just give you my other question.
You can answer them at the same time.
So that was one.
And then the other was the sections
that you've provided like the one
that's on the screen are going
through vegetated areas.
And I was wondering.
What happens at the Plaza in
front of Jefferson?
Had that already sunk by
the time the Jefferson?
No, I guess that was built.
Wall was rebuilt at the same time.
So what happens at the Plaza?
Do you need to regrade the Plaza in
front of the memorial or is that OK?
OK, let me go to your first question.
Uh, so we're we're actually working in datums
when we start talking about elevations.
But let's let's get rid of that.
Let's talk about mean tide level.
That was the historic height of the
foundation was at mean tide level and six
feet above that was the top of the seawall.
Today's mean tide level using the datum
that we're using for this project,
which is NAV D 88, is negative 1.25.
So if we. Add 6 feet on top of
negative 1.25 we get to 4.75,
so it's it's really taking exactly
what they did then which was wanting
a wall that was six feet above mean
tide level and recreating a wall
that is 6 feet above mean tide level
today with today's water levels.
That makes sense.
Yes, I guess that's surprising
to me that the mean time level
is lower than it was before.
Is it just that the the storm events or or
like the the unusual conditions are higher?
It's all to do with with datums.
Water level was definitely lower
than and I believe water levels have
come up since that time and I'm
going to say approximately 1.5 feet.
So if we were looking at the mean
tide level then it would have been
negative 2.75 or something similar.
OK,
so maybe it's would be just
easier for those of us who are not
familiar with all these datums.
Is the absolute if.
If there's anything such
as an absolute like what,
where are you going with the top of this
wall compared to where it was historically?
Can is there. Is there a?
Is there a more absolute datum than
that you can give us an absolute datum?
No.
Now if if I were to say if these
if this land did not sink at all,
we would be 1.5 feet higher than what it
used to be only because sea level rise has.
Has caused water levels to be approximately
1.5 feet higher than they are today.
OK, OK,
that's, that's,
that's helpful actually.
So so it doesn't have
anything to do with the.
The visibility of the
wall from the water side,
but you are actually raising it
about a foot and a half in order
to accommodate higher water level.
From from its original construction,
yes, but.
But as we we mentioned, all right,
now it's like zero. Yeah, right. Right.
They've all sunken into the ground.
Unfortunately,
the the Plaza for your second question,
the Plaza directly in front
of Jefferson Memorial.
That was worked on within the past 20 years.
That's saying exactly as it is.
It is a separate system.
It's on its own pile foundation.
So we are tying our system.
Into the steps there, but they are not.
They are mutually exclusive systems.
So that was that big construction
project that went.
That happened not too long ago
that brought it up to the level
that you needed to be.
Correct for the Jefferson Memorial,
which is actually higher there.
Excuse me? Their elevation is
roughly 5.75 point 8 for the edge
of the seawall in the Plaza area.
So we will actually be below that,
the upland behind the seawall
in Jefferson Memorial.
That whole area.
Kim Lovely showed that picture
during its construction,
where it was being filled in
that was filled into the same
elevation as the sea wall.
At that time, and it's all sunken.
So that's what has created this
bit of a bathtub effect where
we have water now ponding and
unable to escape behind the
sea wall in Jefferson Memorial.
OK.
Thank you.
David.
Alright, thank you.
I just had a follow up on Sarah's
question about the Jefferson Memorial
and also wanted to just sort of agree
with the consensus of of the speakers
you've heard from already that this
seems to be a very straightforward,
very understandable,
rational way of approaching the problem.
The question I had was about
the Jefferson Memorial,
and I think it would be helpful
if you could provide a sort of
an elevation view of the wall.
Where it connects to the Jefferson Memorial.
Because I had the same question,
I'm trying to figure out my head. OK,
what is the relative heights of the walls?
And if if Jefferson is the
Jefferson Plaza is higher,
that's I guess a good thing.
But just showing how you will.
Make that adjustment from the
height of the Jefferson Plaza
to the to the title basin wall.
I mean, I assume it just gradually scoops up,
but just seeing that in elevation
at some point would be helpful.
And and similarly where it
joins the the inlet bridge,
how that joint between,
what is the feature that remains
and the features that the wall
features that will be changed,
how how that will look in elevation?
And another, just another minor point too.
I was scratching my head a little
bit when you showed the the graph of
the the flood levels where the flood
levels are shown on the horizontal
scale rather than the vertical scale.
And I I realize that it fits better
in the in the landscape paper size,
but it's a little bit counterintuitive
to show water height in the horizontal
rather than the vertical. Not a big deal,
but just you get used to it after a while.
I like showing lines that go down versus
lines that go showing growing up, yes.
And you have the other way right?
You understand? Absolutely. OK.
So to address your your first question and
I'm sorry that we don't have a picture of it.
But at the Jefferson Memorial,
there is granite steps and.
Columns, so let's call them.
They're they're large concrete blocks
on either side of those steps.
The new seawall will actually
engulf about two of those steps,
but still be below the grade
of the Jefferson Plaza.
So there will be those two steps that take
you down onto the top of the sea wall.
Now, there is a separate ADA
access point for for ADA.
Purposes and as I mentioned,
these are two separate systems.
We will not be tying into their
foundation or their foundation system
and ours will just abut up against
those those steps and that interface.
Again,
I kind of wish we had a a picture for that.
Sure, but the explanation is very helpful.
Thanks. OK, great.
And then for the inlet bridge,
right now,
we did have that one photo of showing
that gap in between the existing
wall and the the inlet bridge.
It's it's again going to be an
abutment between this system and
that the connection or I should say
the the water tight or sand tight
connection will be much better as there
they'll be newer grout or or newer.
Sheets that prevent soil migration
through or around,
but it will not be tied directly
into the the inlet bridge.
It will just about next to it
as a separate system.
The the one area we are still working out
is the North End of Tidal Basin West.
As you likely noticed,
this does not have a clean endpoint.
This is a next to a pathway that
leads up to Franklin Delator.
This will require a transition
for for possible future elevation
of the sea walls in that area.
So for now there will be a ramp or
an ADA connection between the two.
Great, very helpful. Thanks.
And Sarah, did you have
another question or comment?
No, sorry, that was leftover.
Kyle, sorry I lost my VPN connection
so I couldn't move back and forth,
but if there's a slide that you want to see.
I'm happy to to move to it.
I I do agree with Margaret.
I don't think we have a photo of
the connection here between the wall
and where the Jefferson Wall meets.
But now I can move through my presentation.
I've reconnected to VPN. Sorry.
Does anybody else have
any questions or comments?
OK. I'll just wait for Kim to
move forward. Sorry, Catherine,
I do have a question. Oh yes.
If you can, you go back to a plant like.
And I just want to make
sure I understand your,
you are actually widening
the path on the West side.
Of the title basin.
So this path I believe and
Margaret can speak up,
but I believe it's under discussion
to widening this due to the sheer
amount of visitors to the park and
not having people having enough access
to walk around the cherry blossoms.
So. The wider you make it, though,
then the more you have to.
Because it doesn't affect the.
And there it was. So I don't know.
This is one of those things.
I don't know what your numbers are, does it?
Does it have to be 18?
I mean it it's it's sort of
balancing here like you know,
tree loss, long term tree loss.
There will be,
so there will be temporary impact
of tree loss that you're gonna feel
for a decade or something like that.
So my question is, does it have you?
Does anybody have any?
Does it have to be the uniform
with all the way around or be
right now it's almost nothing.
You you're going from, you know,
almost nothing to 18 is would
10 feet be OK with nine?
So this is 8 feet right now.
Yeah. Deceptive. Alright.
Yes, it is deceptive but that is 80.
So you're big,
but you're basically doubling it.
It's under consideration, OK.
So right now it is a proposed
walkway with that we are looking
at and we're looking at it in
terms of ADA and use and people
on bikes and scooters and walking
there is room for it to to change.
So we are still looking at it,
but for,
for permitting and and looking
at impact purposes,
we're we're looking at a maximum of 18.
I'm just wondering if there's
any consideration because it's
the most remote part with.
Higher impact potential in
terms of tree loss is there.
Any other is it is it?
You're saying you're considering up to 18 is.
Is it reasonable that you might not make
it that big just to see what you what?
What you can do to?
Minimize that the the tree loss.
We are still still evaluating it.
This is for the tidal basin right now.
West Potomac Park will not
have a a walk walk.
Uh, sorry. Along the river.
You're saying I'm talking
about on the title base?
So this will just go to graphs.
Yeah. And that that seems to be
less have less impact. It's hard.
It's a little hard to understand unless
you actually have to map it then on with,
with with very, very tight top topography
lines on and plan to understand.
You know where the and and then all
the trees you know, surveyed and stuff.
So it's a little hard to understand exactly.
I I just wonder if you know you're gonna.
It seems like you probably have
heavier traffic on the north and
east sides of the title base and
then you do on the West Southwest.
But I could be wrong.
Yeah, I I think it's a.
I think it's a circular route.
I I don't know that we know exactly
where where people are hopping off
and on you are correct that there
are two walking pathways though in
that location on Tidal Basin West,
there's the upper one along the access Rd.
And then there's the the
lower one along the water.
So there are two ways to
experience that location.
I I think we're we're still
we're still looking at it.
We're still assessing where
it's appropriate. OK.
I I actually, since I've been thinking
about this, I I I'm going to ask what
maybe a kind of a dumb question.
You know, we spent a lot of time 10 years
ago thinking about perimeter security
for the Thomas Jefferson Memorial.
And then you've done some
accessibility improvements, but.
My am I forgetting that that comprehensive
perimeter security was never undertaken?
Is that correct? That's correct.
And we're looking at doing a.
We've been calling it a tidal basin master
plan to help us make that decision.
We may be changing the name of it,
but basically we are we are
still considering.
A perimeter security barrier.
Your call the where that was going.
These intersections with the edge was,
as I recall, was going to be handled through
a few bollards and some landscape walls.
Cool. Is that correct?
I mean, I guess right now it's probably it.
It's been so long,
it's kind of it's kind of.
Yeah.
It's just you don't want to do something.
Precludes the implementation,
but I don't even know what you're
implementing anymore, and you may not either,
because you don't know where expensive there.
I think you're right, Tom.
What you remember about the past solution,
I don't think that we're relying
on on any of that at this moment.
It is something that will be taken
up in the title Basin Master Plan.
OK. Well, the only question is,
is there anything here that
is somehow missing a key?
You'd hate to build and have
to rip it up because you,
oops, we forgot the whatever.
You know, I don't think that's an issue.
It's just it's just and I and I,
from my point of view,
I'm I think it's better to worry about
the flood protection at the moment.
Yes.
And we've talked about we we've talked about,
you know,
we're we're doing this huge project,
we're doing this and it's going to stay
for hopefully another 50 to 100 years.
It's a good it's a,
it's a really important needful investment.
So and I think it's all good.
I just I I'm just thinking of all
these other kind of projects that
touch this directly, so that's all.
Thanks. Thank you.
We can probably, I think, Scroll down
to the rest of the presentation.
I think there's a maybe a couple more
slides showing where everything is.
Yes, there we go.
So any comments are requested
by September 12th and you can
provide comments. At our website
parkplanning.nps.gov and just
search for seawall rehabilitation.
You can also send your comments
to our Superintendent if you
would like to use snail mail.
So once again, none of the comment the
comments are listened to at this meeting,
but they are not formal comments.
So we're hoping to, I shouldn't
say we're hoping we will have
the project contracted by 2023.
September of 2023 and then.
It looks like it'll be about
36 months for construction.
Once again, thank you all for joining us.
Ohh Lee, I think you have a question.
Yes, thanks Catherine.
When do you anticipate submitting to
the Commissions both CFA and NCPC?
Will that be mid fall or late fall?
UM, possibly mid fall.
I don't know. I don't know that
we've really talked that one through.
Well, just my thinking is this would
probably be initially a preliminary.
I don't think it would require a
concept review from our Commission,
I think because the strategies sound and
there's not going to be really options.
So just keep that in mind.
So I'm sure we'll be chatting,
but just always good to know kind
of time frames when you think you
will be dropping a submission.
Thank you. Thank you.
And Catherine,
is this you may have already said
this is this presentation going to
be provided to us or do we need to
go to Pepsi to to to get a copy?
It will definitely be on Pepsi and I'm
certainly happy to send it around.
I would appreciate that. Thank you.
Patient is already up on Pepsi and
was attached to this meeting invite.
Thanks Tammy.
And it looks like we have one more
question or comment. Good morning.
So I appreciate the slide that
was just shown with some of the
timeline for construction in that
what is the long term planning
for mitigation issues in the area?
You can see some from some of
the photos of some of the areas
were not touched for a long time.
So what is the funding look like and
what is the process going to look
look like for delayed maintenance
and and and moving forward on
this so that these same issues
aren't happening in these areas?
That's a great question.
I don't know that we actually have
a plan for that at this point.
I don't know, Brent.
I know our our next our next
big steps are East Potomac Park,
both along the river and along the channel.
But I don't know that we have any definitive
plans for the rest of the title basin.
Yeah, not at this time.
And that is correct.
You know, for us,
we'll be looking at going
to the East Potomac Park,
neither as you mentioned earlier,
we'll be looking at doing the
master plan work for the title basin
and what would come out of that,
of course,
would help dictate further
phases of the tidal basin.
We're just eliminating that
frequency eliminates most of
the problem with this project.
It does eliminate the frequency of
the flooding with the majority of the
tidal basin, so you won't have that.
You don't have that maintenance
costs associated with that, so.
Have assessments or studies been done
for long term climate change impact
and flooding in the area right now,
a lot of the tribes I work for,
a tribe in the state of Virginia,
we're looking at flooding and climate
change impact in certain regions
100 years out have studies and for
the tidal basin been done that
that far out in future planning.
Margaret, address that.
Oh, go ahead, Katherine.
No, no, go ahead.
So we we have been looking at all of
the various outputs from from NOAA
and Army Corps of Engineers on climate
change in and around the DC area.
We understand, you know,
this area is particularly impacted
because it has the vertical land
movement of the settlement at this site,
coupled with the increase of
sea level rise here,
as I mentioned over the past 100 years,
the water levels have come up about
1.5 feet and their forecasted to.
To increase in the future and those
those what we've been using in our
analysis in House is the intermediate
level of Army Corps of Engineers
forecasting for sea level rise.
But what we have on jointly been
looking at is we've installed water
level gauges within the tidal basin.
We'll be looking at the influence of
the the inlet gates and the outlet
gates for vertical water level
variation within the tidal basin.
Compared to the Washington Channel,
which has its own water level
gauge which has been in existence
for almost 100 years now,
so we have a good amount of data and
if we continue along that linear line
that we do see water levels going up
at that rate of about 1.5 per 100 years.
But for the analysis that I
showed on on that one page,
looking at the future,
that does include the increase,
the exponential increase of water levels.
In the future as well.
So I guess that should also
highlight and sorry I'm now,
I'm just being nerdy the the water level,
the height of the sea walls and and
I should point this out because
it wasn't all the cross sections.
It doesn't stop all water levels
from going over the top.
Last year we had an event that was
about 5.6 that would overtop these walls.
But prior to that the last event
was in the early 2000s.
Now what we are doing is making
this area much more.
Resilient in that this is
a stormwater runoff.
So the water level goes up and it
comes right back down and doesn't
pond on the surface and therefore
dries out very quickly and causes
little to no damage within this site.
Thank you, Kim. You actually
answered my next question,
which was if you were going to
be installing into any type of
monitoring systems for water
level and that under this project.
So I appreciate it. Thank you.
We're currently under a two
year water level monitoring.
All right. Anybody else?
We'll go ahead and and the meeting.
Thank you once again for joining us.