Monitor - Maasvlakte 2

Monitor

Contents
Foreword 3
Introduction 5
1. Silt 7
2. Benthos 15
3. Spring peak 21
4. Underwater noise 29
5. Flow pattern 35
6. Archaeology 41
7. To be continued … 51

Foreword
The seawall around Maasvlakte 2 has been closed
and the first container terminals on the new deepsea
quays are under construction. Next year, right on
schedule, the first phase of the construction of
Maasvlakte 2 will be complete. By then, about
220 million m³ of sand will have been extracted from
the sea and the Netherlands will be 20 km² bigger.
The construction work has been carried out in
accordance with the necessary permits. These
permits contain, among things, extensive regulations
on controlling the effects of the construction work in
the sea and of the sand extraction on the North Sea.
The Port of Rotterdam Authority will implement
a comprehensive measuring programme for this
purpose. That will result in extensive technical
reports. These so-called monitoring reports will be
presented periodically to the competent authorities.
In the document before you, we have set out the
main points. In this way, everyone who so wishes
can find out about the activities and the results.
This Maasvlakte 2 Monitor also contains a description
of the fascinating results of the study into the areas
of archaeological and palaeontological interest
involved with Maasvlakte 2.
Before construction work could begin, the possible
effects of the construction work were studied.
Extensive research charted as accurately as possible
the uncertainties and the potentially most unfavourable
situations in terms of the effects on nature.
By looking at which effects actually occur, during the
construction, the assumptions made in the environmental
studies conducted are tested against reality.
Divergent results can possibly lead to changes in
the measures taken. In addition, the measuring
programme leads to new knowledge. Future projects
can benefit from this. This means that the measurements
are not only important as a finger on the
pulse, but mainly also as something from which
to learn. And the latter is precisely what we are
doing with Maasvlakte 2. Measuring then suddenly
becomes exciting and useful. It gives us a better
understanding of the actual effects and the natural
processes in the coastal zone. The change ability
in the populations of shellfish, but also the currents
along the coast, are striking examples of this.
The results of the monitoring programme confirm,
for the time being, that we based our predictions
on the most sombre scenarios. Moreover, measurements
remain within the predicted values. The
deviations are also so limited that it will be difficult
to distinguish possible patterns of effects from
natural patterns. What is particularly striking is that
there is great natural variation in the coastal zone.
As far as measuring the effects of the construction
is concerned, a number of elements are already at
the finalisation stage. Work is (partially) completed
and the measurements carried out.
For example, final conclusions have already been
drawn regarding the effects on the shellfish larvae
in the Voordelta, among other things. A number
of other issues will be looked at in more detail.
For example, how new life is establishing itself in
the sand extraction areas where the seabed has been
deepened to a maximum 20 metres. This means that
the measuring work has not quite finished.
I hope that this document will not only make it clear
that care was taken in constructing Maasvlakte 2,
but also that new knowledge was added to the public
domain. This also includes the attention paid to the
discovery of fossils in the sand extraction area and
the remains of prehistoric human habitation deep
in the Yangtzehaven, the future access route to
Maasvlakte 2.
I hope you enjoy reading this Monitor.
Tiedo Vellinga
Project Organisation Maasvlakte 2
Port of Rotterdam Authority
3

Introduction
The first edition of the Maasvlakte 2 Monitor, issued in August 2010, focused primarily on the possible
consequences and effects of the construction of Maasvlakte 2 and how the Port of Rotterdam Authority
monitors this. Apart from the baseline measurement which took its starting point in 2006, the monitoring
programme had only just been launched, so that no far-reaching results could yet be reported.
Now, two years after publication of the first Maasvlakte 2 Monitor, the realisation of Maasvlakte 2 is well
advanced, the monitoring is well under way and various results of the monitoring can be presented.
This applies mainly to the monitoring results in connection with the sand extraction on the North Sea
and the construction of the new land itself. Results from monitoring the existence of Maasvlakte 2 will
be covered in the next edition of the Maasvlakte 2 Monitor.
5
The public edition you have before you looks in more detail at: silt (distribution), life on the water bed
(benthos), mismatch/spring peak, underwater noise, flow pattern and archaeology/palaeontology.

What does the distribution pattern of silt in the water off the
Dutch coast look like? To what extent does the floating silt in
the water column increase as a result of the sand extraction?
And can the possible increase in the silt concentration have
consequences for marine life and the food available for sea birds?
1.
Monitoring silt concentrations
along Dutch coast
Effect on the food chain
The dredging operations at sea for the construction
of Maasvlakte 2 lead to extra silt in the water. Silt in
the water makes it turbid, as a result of which there
is less light for the algae which float in the water
(phytoplankton). This allegedly slows down the
growth of the algae and their spring peak could occur
at a different time (see also chapter on monitoring
spring peak). As a result of this, there could be less
food available for small creatures (zooplankton) in
the water and for creatures living on the water bed,
such as shells and worms. This zooplankton and the
benthic fauna are, in turn, eaten by fish. Birds, and
diving ducks in particular, also feed on benthic fauna.
Other birds, such as gulls, enjoy fish. Reduced growth
in algae therefore has possible consequences for the
whole food chain. It is therefore important to know
what the silt distribution patterns look like before,
during and after construction. By comparing these
patterns, one can see if the sand extraction
is having a possible effect.
7

Charting the silt
When extending the permit under the Earth
8
Removal Act, it was agreed with the Port of
Rotterdam Authority that the silt concentrations
would be charted in the water column in the sand
extraction area, in the immediate vicinity of this
and in a larger (reference) area off the coast.
This mainly involves monitoring: establishing
if the sand extraction for Maasvlakte 2 caused
an increase in the silt concentration in the water
column. And, if so, if this increase is within the
range calculated in the EIA Construction.
Great variation in distribution
The permit under the Earth Removal Act states
that measurements must be taken every fourteen
days in three section lines (imaginary lines)
across the coastal silt profiles in the water column.
The Port of Rotterdam Authority and the scientists
involved in the monitoring study wondered if the
effect of the sand extraction on the Dutch coast
could be measured reliably enough in this way.
The silt concentrations in the water already fluctuate
massively under natural conditions in terms of space
and time. For silt concentrations, it is not therefore
a question of coincidental values at a certain time
in a certain place, but long-term deviations which
could possibly be caused by the construction of
Maasvlakte 2. These deviations cannot therefore
be explained by, for example, fluctuations in the
climate or incidental peaks, such as heavy storms
or highly changeable volumes of silt brought from
the rivers and from the coastal waters of Zeeland,
Flanders and France.
Silt measurements at sea are not so easy to
interpret. A heavy storm, for example, has a great
effect on the distribution of silt; the higher waves
mean that silt is released from the bed. Only after
some time will such silt return to the bed, for
example as a result of the activity of benthic fauna.
An increased flow velocity (during ebb and flood)
also brings to the surface silt that forms a thin
layer on the bed during the turning tide. It would
be difficult or impossible to interpret the measuring
results with the usual statistical methods and with
the measurements at sea prescribed in the permit
under the Earth Removal Act, as a result of which
it might be impossible to measure the consequences
of the sand extraction.
Time to meet with the scientists and look at whether
or not a measuring method could be developed that
would be able to make reliable pronouncements
about the silt distribution. In consultation with and
following approval from the government, the decision
was made, in 2008, to set up a new monitoring
method to provide much greater insight into the
distribution of the extra silt off the Dutch coast.
New measuring and monitoring
method
The basis for determining the amounts of silt is
an innovative method based on a combination
of calculation models and measurements: MoS 2 ,
which stands for Model-Supported Monitoring
or SPM (Suspended Particulate Matter, silt).
With model-supported monitoring, the water
movement and water quality are calculated using
calculation models, which are fed with measurement
data from satellites and sea measurements.
Not only the competent authority was involved
in the development of this innovative approach,
but also external scientific reviewers from the
Netherlands and Belgium.

A precursor of this model, subsidised by the NIVR
(Netherlands Agency for Aerospace Programmes)
and the Port of Rotterdam Authority, was developed
by Deltares and the Institute for Environmental
Studies (IVM) of the VU University Amsterdam.
Model, satellite and sea samples
Model-supported monitoring is complicated, hence
a brief explanation. Using the Deltares models,
calculations are made at ten-minute intervals retrospectively,
when the weather data and information
on river outflows are available, of how the water
moves, how much silt is released from the bottom
and how the silt rises and falls in the water column.
However good the models might be, they always
deviate from reality. The models can be adjusted
on the basis of observations. Data from remote
sensing (observations using satellites) is used for
these adjustments. On clear nights, the surface
of the sea is observed regularly from satellites.
The satellite that supplies the images passes once
a day. The pictures encompass the whole of the
North Sea, insofar as visible in the light spectrum.
Based on the colour of the water, an estimate can
be made of the quantity of silt and algae present
in the topmost metres of the water column.
Finally, there is the uncertainty regarding what
happens deeper in the water (in the water column).
For this reason, the model results are also validated
using the results of the measurements at sea which
the Port of Rotterdam Authority itself takes using
the Silt Profiler (see box on page 13 ‘Measurements
at sea’) and measurements from the Directorate-
General for Public Works and Water Management
and other parties.
Silt atlases
After combining and assimilating a year’s data, silt
distribution maps are made, for example as weekly
or monthly averages of the silt concentrations.
These maps are put into a silt atlas and can be
used when deducing possible ecological effects
of the sand extraction.
The silt atlases can subsequently be used to
check the predictions in the environmental impact
assessment. Making the silt atlases is time consuming.
For instance, it took three years to set up the
model and compute the data from 2007 (baseline
measurement) with MoS 2 , the satellite images and
field measurements. The first silt atlas for 2007 has
now been published. Deltares is well advanced
with the production of the silt atlases for the years
2003-2008. The experience gained when creating
the atlas for 2007 is being incorporated into the
MoS 2 method. A decision will then be made on how
the years 2009-2013 with the sand extraction will
be calculated.
There is variation in the values measured, which
is largely dependent on the distance from the
coast (the water depth) and the time in the tidal
cycle (flow velocity).
Results
A provisional analysis shows that there appears
to be no evidence of significant increases in the
floating silt content outside the sand extraction
area on the basis of the measurements in 2009,
2010 and 2011. This means that, in accordance
with the EIA and the Appropriate Evaluation,
no effects can be expected on the Natura 2000
areas North Sea coastal zone and Wadden Sea.
9

10
More insight
The combination of data with model results is
referred to as data assimilation. The technique
used (ensemble Kalman filtering) is also used
for weather forecasts. If parameters of the model
are also modified (parameter assimilation), this
ultimately leads to increasingly better models,
which produce the most reliable results. This
method must lead to a smaller margin of error
and provide more insight into the different silt
flows. The procedure has been tested and it
transpires that the new monitoring model, the
satellite observations and the measurements
at sea provide a reliable picture and that it is
possible to produce silt maps and silt atlases.

New knowledge
11
Fresh water in sea
One of the striking things noted during the
monitoring is the great influence exerted by
the hugely variable volume of fresh water that
flows into the sea from the Nieuwe Waterweg
and the Haringvliet. Furthermore, the size and
location of the area that is influenced by the
fresh water varies due to the direction of the
tidal flow and the wind. This helps determine
the transport of silt along the coast. The measurements
made by the Port of Rotterdam
Authority, particularly the 13 and 26 hour
measurements, were used to chart the
behaviour of the fresh(er) water (Region
of Freshwater Influence).
The behaviour of the region of freshwater is
extremely variable in terms of time and space
(both location and size). The measurements
and the analysis of the results have provided
a better understanding of this phenomenon.
Bad weather and silt
The crew of the BRA7 and the Port of Rotterdam
Authority employees who carry out measurements
at sea using the Silt Profiler even take to the water
at wind speeds of 8 or 9 on the Beaufort scale (BF)
and also conduct their research under these
difficult conditions. Most survey ships still return
to port at wind speeds in excess of 5. We therefore
now have a much better understanding of the
effect of storms at sea and the sediment that is
brought up from the bottom as a result.
It transpires from the figures that the silt
concentrations during a storm can increase
by a factor of between 10 and 100, because
the fine particles from the bottom are churned
up and over by the power of the waves and
end up in the water column as a result.
Water turbulence tamed?
The turbulence in the water is a source of error
in the models. Students cooperated in doctoral
research to see if they could measure the water
turbulence and could incorporate it into the model.

12
‘We now know a lot more about the silt distribution off the Dutch coast’
Meinte Blaas, senior adviser/researcher at Deltares, project manager for MoS 2
‘Silt distribution is a very complex issue, with lots
of natural variation in volumes, in terms of time
and space. There are many natural causes of
sudden increases: changing currents due to tide
and wind, fluctuating river outflows due to rain and
drought, and variation in waves between calm
weather and storms. In addition, there is a lot of
human intervention, such as sand suppletion on
the coast and the construction of the ‘Sand Motor’
at Delfland. The sand extraction for the construction
of Maasvlakte 2 has been added to this. What
does that silt do? We have been given a unique
opportunity to develop a new measuring method
for model-supported monitoring and to combine
the data from the updated model with data from
satellite images and from the measurements at
sea. We now get a much more complete picture
of the silt distribution and the fluctuations in silt
concentrations over a large area off the Dutch
coast. We can make reliable statements about
what happens in a week.
The Port of Rotterdam Authority was extremely
progressive and went further than they had to.
They made the fundamental choice to not only
meet the permit-related obligations; they truly
want to take measurements to find out and
learn things.
The model meets the scientific requirements
and the information from the satellites and
models shows a great degree of consistency
with the data from the measurements at sea.
I also envisage other applications for this
method. I think that it will also be possible,
in the future, to make more reliable predictions
before the start of large-scale infrastructural
projects at sea. In essence, the method could
also be used to predict algae growth.’

Measurements at sea
In 2007, an extensive baseline measurement
was made of the silt. In April, June and October,
samples were taken at 100 locations, from Petten
to Vlissingen. These locations were divided
over approximately 20 section lines with at least
four points per section line, which were in turn
sub divided according to the changes in depth.
In the area around the sand extraction pit,
the section lines are longer.
In 2009, 2010 and 2011, these measurements
were repeated. In addition to the standard
measurements (six times a year at 50 sampling
points), measurements were taken twice in a
period of 26 consecutive hours (two full tidal
cycles) and a few times in a 13-hour cycle (one
tidal cycle with ebb and flood). Furthermore,
measurements were taken during a storm and
behind a trailing suction hopper dredger during
the sand extraction.
Silt Profiler
The vertical (depth) profiles were measured using
a Silt Profiler, a stainless steel frame with a large
number of built-in measuring instruments.
Since 2009, a newly built Silt Profiler has been in
use, with more advanced measuring equipment.
The Silt Profiler is lowered into the water from a
fishing boat that was converted into a survey ship,
in order to take measurements over the whole
depth and to take water samples at different
depths. Measurements are taken of such things as
silt content, grain size of the silt, amount of algae,
clarity of the water (colour), its salt content and
temperature. The measuring equipment is calibrated
using the water samples, the amount of floating
material, the organic fraction and the chlorophyll
level of which are determined.
At more than 100 measurement points, three times
a year, the measuring platform is lowered from a
ship during six surveys, in which 50 sample points
are visited every time.
Whilst the measuring platform is lowered and then
raised again, measurements are taken ten times
a second (silt content, temperature, algae) or
once a second (colour and grain size distribution).
In this way, we therefore know the quantity of silt
and algae, the temperature and salt level of the
water at every depth.
13

To what extent has the benthos in and on the seabed close to the sand
extraction area been affected by the sand extraction? What is the impact
of the floating silt released in the water column on the marine ecosystem?
2.
Monitoring benthos
More than 300 species of benthic organisms live
in and on the bottom of the North Sea. These are
invertebrate organisms, otherwise known as
(macrozoo)benthos. Within the benthos, a distinction
is made between two groups. First of all, the creatures
living in the seabed, the infauna. The infauna
include many species of worm, such as clam worms,
tube worms and bristle worms. The worms vary
in size from 1 millimetre to 10 centimetres. A lot of
shellfish also live in the seabed, such as cockles,
otter shells and razor shells (Ensis). The second
group are the living creatures which live on or
just above the seabed: the epifauna. Well-known
examples of this include shrimps, hermit crabs,
crabs and starfish.
Ecosystem
The floating silt mainly has an impact on the growth
of algae. The assumption in the environmental
impact assessment was that the increased silt
concentrations due to the sand extraction could
lead to fewer algae.
15

16
Living and dead algae (bacteria) are a food source
for the creatures which live in and on the bottom
of the North Sea. Temporarily, there would thus be
less food available for this benthic fauna. Also, they
would perhaps have to work harder to filter the extra
silt out of the water, thereby ingesting less food and,
as a result, showing less growth. If we look further
in the ecosystem, then less food would perhaps
be available for, for example, flatfish which eat
clam worms and graze on the siphons of shellfish.
Siphons are feeding tubes, through which they
suck in and expel water. Various species of duck
also dive to the bottom in search of shellfish.
The research into the mismatch between the spring
peak of algae and the presence of cockle larvae has
already shown that there are great changes during
the year in the quantity, composition and production
of the algae which float in the water (phytoplankton)
and that hardly any effect can be seen from the extra
silt released by the construction of Maasvlakte 2.
Benthic fauna live longer than algae and should
present a clearer and more stable picture of the
state of the ecosystem in the North Sea, as well
as the effects of the sand extraction.
What lives at the bottom of the
North Sea?
In order to determine the effects of the extra silt
released as a result of the sand extraction, baseline
measurements were made in the spring of 2006,
2008 and 2009. The last baseline measurement
only concerned the area that will be investigated
a few years after the sand extraction in order to
find out if the benthos is recovering well, or if
recolonisation by benthic fauna is taking place
and on what timescale.
In this period, no or hardly any sand was extracted.
By repeating these measurements later during the
sand extraction operations, it must be possible to
determine the changes in numbers and species.
The samples from the seabed were taken using
the box corer (infauna) and the deep-digging dredge
(infauna, and epifauna in particular).

Benthic fauna in the seabed: box corer
The creatures which live in the seabed are brought
to the surface using a box corer. This is a weighted
tube, about 32 centimetres in diameter. It is lowered
to the bottom and penetrates about 20 centimetres
into the seabed. With the aid of a clever mechanism,
a metal plate swings under the corer, after which a
‘cake’ from the seabed is hauled on board. Small
samples are taken from this cake to determine the
granular distribution of the sediment in the bed.
The rest of the sample is sieved through a sieve
with a one-millimetre mesh to largely remove the
sand. The residue is then preserved by putting it in
formalin (fixation in pH-neutralised formaldehyde).
In the laboratory, the organisms are sorted under
a stereomicroscope and counted and weighed per
species. The following variables can be determined:
species composition, distribution of species and
groups of species, density (numbers per m²) and
biomass (ash-free dry weight per m²). From these
samples, the presence and distribution of specific
species can also be determined. This box corer
survey was carried out most years by the
Netherlands Institute for Ecological Research
(NIOO-KNAW).
Benthic fauna on the seabed:
deep-digging dredge
Sampling with the aid of the deep-digging dredge
focuses mainly on the epifauna and the larger and
rarer species which have a lower density (number
per m²). In this way, information is obtained to
supplement that from the box corer samples.
The deep-digging dredge consists of a metal mesh
cage fixed to a sledge. The base plate of the sledge
is fitted with two vertical blades and a horizontal,
sloping blade. The deep-digging dredge is dragged
along the seabed and, in this way, cuts a strip about
10 centimetres wide, 7-10 centimetres deep and
about 150 metres long from the bed. The material
ends up in the cage and the water that flows past
ensures that sand and other small particles, including
the tiniest worms and young shellfish, are rinsed out
of the sample. The result is a sample that contains
the larger species of infauna and epifauna, originating
from an area of around 15 m².
On board the survey ship, density, biomass, distribution
and size category are determined. In the
laboratory, the ash-free dry weight is determined
retrospectively. The deep-digging dredge provides
information on, for example, the numbers of cockles,
nuns, beach shells, mussels, lesser sand eels and
gobies. This research was carried out by IMARES,
with the aid of the survey ship Isis.
Baseline measurements at
300 locations
The first baseline measurement of the benthos was
carried out in 2006. The area sampled was between
IJmuiden and the Kop van Goeree, and was about
50 kilometres wide, at right angles to the coast.
The second baseline measurement of the benthos
took place in 2008 and had a more rectangular
shape. This modification was based on the scenario
predictions from the silt distribution along the North
Sea coast. The boundaries were at Petten and
Westkapelle (Walcheren) and the width of the survey
area was reduced to a maximum 35 kilometres at
right angles to the coast.
For the baseline measurements, sediment samples
were taken from 300 places in 2006 and 2008. The
density of the sampling points around the mouth of the
port is greater, in order to get an even better picture
of the benthic community in the area where higher
17

18
silt concentrations were already present prior to the
sand extraction. The total sampling area is so large,
because the areas which are not affected can serve
as reference area.
Measurements 2009, 2010, 2011 and 2012
In the spring of 2009, the sampling programme
involved 100 points in and around the sand extraction
pits as baseline measurement for the recolonisation.
Sampling of the whole area was repeated during
the sand extraction in 2010 and 2011 and will be
carried out again in 2012. The first T1 recolonisation
measurement will be taken in 2013.
Results:
no species disappeared
The assumption was of a more or less constant
natural environment on the bed of the North Sea,
and that it would show the same pattern on average
and in the longer term. Due to the sand extraction,
more silt was expected to appear on the seabed
in the vicinity of the sand extraction pit, thereby
changing the average pattern. Despite the more
or less constant environment in the North Sea,
on average, it was often noted already that numbers
and species of benthic fauna could differ greatly in
space and time. During some periods (time), there
are many species of certain shellfish and sometimes
few. In 2006, for example, there were few sand
mason worms to the north of the future sand
extraction area, and in 2008 a lot.
There is also great spatial variation. Within just a
few metres, the composition of the marine benthos
can be completely different. The bristle worm,
which was not found at one measuring point, was
present in large numbers elsewhere. A species
that seems to have disappeared can be found
living happily in or on the bottom 100 metres further
along. This variation in time and space makes it
much more complicated than anticipated to make
well-founded statements and make connections
with the sand extraction.
Minor effect
In order to be able to demonstrate changes given
this great natural variation in the benthos, a large
number of samples were therefore taken at
300 sampling points (including reference points).
This would supposedly make it possible to determine
a spatial pattern, which could be corrected
for differences in the total quantity between years.
On the basis of the surveys, there only seems to
have been a minor effect on the benthic life in the
vicinity of the sand extraction area.
One conclusion that can however already be
drawn is that no species disappeared during the
sand extraction.
Unpredictable
We have found out a lot more about the unpredictable
nature of the occurrence of benthic fauna. As a result,
it will be difficult to differentiate between the possible
effects of sand extraction and natural patterns. Insight
into the benthic fauna was obtained at 300 locations.

Improved deep-digging dredge
How efficient is the deep-digging dredge? That
is what the Port of Rotterdam Authority wanted
to know, because a reliable picture of the benthos
was needed. The old deep-digging dredge
proved to be less accurate than people thought.
Two things were improved:
• The counting wheel was fixed during lowering
and raising, so that the distance covered
during scraping could be determined more
accurately. The dredge moves over the
bottom. A counting wheel is attached to
the dredge with a hinged arm. The distance
covered is ascertained from the number of
rotations of the counting wheel. However,
the counting wheel apparently kept on turning
if the front of the dredge was suspended to
about 15 centimetres above the seabed.
The decision was therefore made to block
the counting wheel as soon as it projected
more than 5 centimetres below the dredge.
• The deep-digging dredge was weighted and
the razor was fixed. Extra equipment was set up
on the deep-digging dredge to measure how
well it made contact with the seabed. The old
deep-digging dredge had a sort of ‘spoiler’,
the purpose of which was to press the dredge
down on the seabed. This was shown not to
work adequately: sometimes, especially with
rough seas, a lot was missed. On the basis
of various experiments, the decision was made
to weight the dredge, to prevent it from leaving
the seabed during dredging.
19

Do the increased concentrations of floating silt during the sand extraction
for Maasvlakte 2 have a negative effect on the growth and availability of
algae? Is there a shift in the spring peak of these algae? Is there, as a result of
this, too little food available for the shellfish larvae which then have to grow?
Does this mismatch between the presence of plenty of (edible) algae and
shellfish larvae ultimately lead to fewer or smaller shellfish on the seabed?
Do the shellfish-eating ducks get too little food in the winter as a result?
With the study into the possible mismatch between
the spring peak in edible algae and the effect of this
on the growth of shellfish larvae and – ultimately –
on the availability of food for shellfish-eating ducks,
a complex chain of effects is evident. This chain
is influenced by a large number of things, such as
water temperature, sunlight, the presence of silt,
the ratio between salt and fresh water, and storms.
Algae growth and turbidity
Algae (phytoplankton) grow – just like plants –
through photosynthesis: they are dependent
on the amount of light in the water. Every year,
in spring, algae grow rapidly, so that there is
suddenly a large quantity of algae in the sea water.
This ‘algal peak’ is also referred to as the spring
bloom. This is because the higher position of the
sun in spring and the longer days mean that the
water warms up and more light is available for
photosynthesis. As a result, algae grow faster.
21

silt in
water
transparency
algae
biomass
weather
conditions
moment of
spring peak
food
quality
amount of
born larvae
grow of
larvae
hydrodyn.
conditions
biomass
breed
grow fallen
breed
biomass
0-year
grow 1 a.f.
years
eatable
biomass
A second possible effect of the increased silt
concentrations is that the cockles which have
settled on the bottom will grow more slowly if
there is more silt in the water. Shellfish filter
organic material as food from the water.
22
diving ducks
Growth slows down if the nutrients they need become
exhausted. Some of the floating silt released in the
water column with the sand extraction is transported
to the Voordelta. If there is more floating silt in the
water, the water becomes cloudier. This reduces
the amount of light in the sea water. The increased
silt concentrations during the sand extraction could
therefore have an effect in this way on the annual
spring algal bloom: the algae growth could be
reduced and the spring bloom could occur later than
normal. For some shellfish larvae, particularly the
cockles, this would be bad news: they emerge from
their eggs in spring and eat certain algae to grow.
Cockle larvae
Under normal conditions, the cockle is the first
species of shellfish to spawn, often even before
the spring algal bloom. The water temperature is
decisive here: if the temperature rises above 12˚C,
the cockles begin to spawn.
The other shellfish species relevant for the study
tend to spawn later. It was for this reason, and
because the cockle is an important source of
food for ducks, that the cockle was chosen for the
monitoring operation. In spring, cockle larvae float
in the water and feed on the for them edible part
of the phytoplankton: these are algae smaller than
20 μm (micrometres, a thousandth of a millimetre).
If the spring peak in edible algae were to shift to
after the peak in the presence of cockle larvae,
we would have a mismatch, because then the two
peaks would not coincide. In this situation, there
could be too little food for the cockle larvae. As a
result, larvae could perhaps die prematurely or be
retarded in their growth before they nest on the
seabed (spatfall).
Cockles
If the shellfish larvae do not catch up on this possible
retarded growth, the cockles on the seabed remain
smaller. This could ultimately lead to less food being
available for Eider ducks and Common Scoters which
dive to the seabed to feed on shellfish.
In doing so, they also take in floating silt. This is
not edible and is expelled. If they take in more silt,
they ingest relatively less food. That could retard
their growth. If these cockles have less meat
weight, that could lead to a temporary decrease
in the amount of food available for shellfish-eating
ducks in the Voordelta. That is because this area
is the foraging area for Eider ducks and Common
Scoters in autumn and winter.
Chain effects
This complicated sequence of effects begins with
the water becoming turbid because the silt concentration
is too high. Hence all the work that went
into the environmental impact assessment to chart,
with the aid of models, the pattern via which the
silt released by the sand extraction is distributed
through the sea water. The environmental impact
assessment is based on the maximum increase
in silt concentration in the worst-case scenario.
The extensive monitoring programme for the silt
survey, in which models are also used, provided
new insights into the distribution pattern of the
silt released.

Assumptions of environmental impact
assessment
In the environmental impact assessment, temporary
negative effects on the food stocks for shellfisheating
ducks were predicted on the basis of
worst-case scenarios. This worst-case effect would
supposedly occur if a lot of sand was extracted in
the spring of 2010, in combination with bad weather
conditions, as a result of which there would be more
silt in the water column anyway. The increased silt
concentration in the Voordelta could rise so much
during the sand extraction that the spring peak in
algae concentration would occur two weeks later.
This could therefore lead to a mismatch between
the presence of high algae concentrations and
shellfish larvae. That could ultimately mean fewer
or smaller cockles being available for the shellfisheating
ducks.
It was implicitly assumed here, on the basis of
scientific literature, that shellfish (cockles) only
spawn once a year, in spring. Another starting point
was that shellfish (cockles), once they have suffered
retarded growth, no longer catch up later in the year;
supposedly, they continue to have lower biomass,
leading to reduced food stocks for the shellfisheating
ducks in this area.
Research questions
In the chain-effect approach, assumptions were
made on a field in which science still has a lot to
discover. High time for field studies at sea and
on the mud flats of the Voordelta, to find out more
about the actual situation.
The main research questions were:
• Was the annual spring algal bloom delayed
as a result of increased silt concentrations?
• If so, was there a resulting mismatch in time
between sufficient high concentrations of algae,
which are important for the growth of shellfish
larvae (cockles), and the presence of these
shellfish larvae which, as a result, would have
less food?
• If so, did this ultimately lead to more limited
availability of food (cockles) for shellfish-eating
ducks in the following autumn and winter?
The Port of Rotterdam Authority was also keen
to answer the following question:
• Is there an actual failure to catch up on the
possible retarded growth in the larval phase
during the shellfish phase following the spatfall?
Do the smaller larvae and the smaller shellfish
no longer grow into shellfish of ‘normal’ size and
volume (biomass) in the autumn and winter?
New measuring approach: water
samples
The most logical research method would be to
answer the questions on the basis of data from
the existing measuring programmes used by the
Directorate-General for Public Works and Water
Management and the measurement data from
the satellite images made from space of the
North Sea (remote sensing).
Using remote sensing, it is possible to monitor the
algae growth and determine the time of the spring
peak. It was not long before this originally proposed
measuring method was abandoned. During the
spring bloom, the algae community consists mainly
of colonies of the algae Phaeocystis. These are
algae which are not edible for shellfish larvae in
this form, due to their size (colonies with a diameter
of approximately 2 millimetres), as the shellfish
larvae themselves only measure about 100-250
micrometres and their mouths a maximum 20 μm.
Determining the spring algal bloom from the
remote sensing observations would therefore not
give a good indication of the availability of food
for shellfish larvae.
The conclusion was that the amount of food (algae)
available and the quantity and size of the cockle
larvae could only be determined by microscopic
analysis of water samples. Also, it would be
necessary to take samples of zero year-old
shellfish at various places on the seabed in
order to determine the possible retarded growth.
Approach
Parallel to setting up the field study, Yvonne van
Kruchten (TU Delft, see box on page 27) carried
out a model study. The purpose of this was to
calculate, using what was known at the time, the
chance of significant retarded growth occurring
among shellfish larvae given different temperature
and turbidity scenarios. This chance proved to
be extremely small. The insights gained via this
study were used to further streamline the planned
field study.
23

In order to gain an understanding of the possible
impact on the effect chain described, water samples
were taken with a high frequency at fixed points
in the Haringvliet estuary in 2009 and 2010, from
the start of the growth season (spring) until into
the early summer. The purpose was to determine
the development of algae in combination with the
development and growth of cockle larvae and their
ensuing settlement on the seabed (spatfall).
Samples of algae, cockle larvae
and cockles
In the spring of 2009 (baseline measurement)
and the spring of 2010 (peak in sand extraction,
April-June), water samples started to be taken just
before the first larvae appeared. This was done at
three locations off the coast of Voorne as soon as
the water temperature reached about 12 degrees
Celsius. As a mismatch of a few days could already
have measurable consequences for the larvae,
measurements were taken very frequently. Twice
a week, samples were taken from the water column
using a water sampler. The samples were always
collected during the same tidal phase.
The shellfish larvae present were then filtered
from the water via the sieve of a plankton net.
A second sample was taken and preserved so
that the phytoplankton in it could settle.
In the laboratory, the following things were
ascertained using a microscope:
• Density, size and species composition of the
algae. Per shape and size, the number of cells
was converted into biomass.
• Density and size of the cockle larvae. Their
speed of growth was determined from the length
of the larvae. At the same time, a number of
physio-chemical parameters were measured,
such as the water temperature and the salt
content of the water in the Haringvliet estuary.
These studies were carried out by ecological
consultancy and research firm Koeman & Bijkerk.
The samples were taken by ATKB (soil, water and
ecology consultants).
Cockles spawn more often
During the measurements, it came to light that an
important assumption of the environmental impact
assessment was incorrect. When determining
the length of the larvae, it transpired that cockles
did not spawn once per growth season, but several
times. New cockle larvae kept appearing in the
water in approximately weekly waves (cohorts).
In the measurements, that was visible as the sudden
appearance of large numbers of small larvae and
the disappearance of the larger larvae, which had
sunk to the bottom to settle there.
By combining data from the literature on the
filtering and assimilation capacity of shellfish
larvae with the research results, a comparison
was made between the energy needs of the
shellfish larvae and the amount of energy
available in the edible algae fraction.
Cockle spawn
In the summer and autumn of 2009 and 2010,
cockle spawn was sought on the mud flats of
Voorne. To do this, the top layer of the ground
(about 5 centimetres) was scraped away during
low tide using a scoop. The shellfish present were
sieved out. The age, shell length and biomass
(fresh weight and ash-free dry weight) of these
shellfish were determined. This study was carried
out by the NIOO-CEME and researchers from the
Port of Rotterdam Authority. In 2009, this study
produced no results because hardly any 0 year-old
shellfish were found in the seabed. Studies were
conducted again on 15 July and 28 October 2010
and cockle spawn was found this time.
25

that the shellfish-eating ducks would not have
26
Conclusion
No mismatch
In the period during which the effects of the sand
extraction operations for Maasvlakte 2 would
supposedly be the greatest, no mismatch occurred
between the spring bloom of edible algae and
the presence of shellfish larvae. The peak in the
density of the edible algae fraction coincided with
the appearance of the shellfish larvae (2009) or
preceded it slightly (2010). In both years, the
shellfish larvae did not therefore miss the algal
peak, considering the fact that they were already
there before the algae volume was at its highest.
The study also revealed that a mismatch cannot
occur, because the cockles produce several cohorts
of larvae. Cockles therefore spread the risk: there
is always at least one group of larvae growing under
sufficiently favourable conditions. This can also be
seen from the 0 year-old cockles in the Haringvliet
estuary, which reached normal size in the autumn
and winter of 2010.
Enough food
It transpires from analysis of the algae composition,
from the estimated amount of food ingested (from
literature and the model) and the estimated energy
needs of shellfish larvae (literature), that there was
enough food available in the water for the shellfish
larvae in both 2009 and 2010. The energy needs for
maximum growth were definitely not always achieved,
but this is far from uncommon in natural systems.
Cockles on the seabed
In 2009, hardly any shellfish were found on the
seabed. This was presumably because the shells
on the bottom had been crushed during spring
storms. The length of the 0 year-old cockles from
2010 does not differ from that of other years.
The length-frequency distributions from various
years reveal considerable variation and show that
the 2010 values fall completely within the natural
variation and range.
In 2010, therefore, no effects of the sand extraction
on the size of the cockles can be ascertained.
This means that there is also no reason to suppose
enough food in the autumn and winter.
Several cohorts and catching up
on retarded growth
So no mismatch. But new knowledge. It transpires
from the studies that cockles spawn several times
per season. In 2009, at least two cohorts could
be identified and in 2010 there were six. In 2010,
the first cohort was present on the first sample
date (26 April) and the last two cohorts on 10 June
and 14 June respectively. Cockles are apparently
insensitive to when the spring bloom occurs.
This picture is confirmed by the shellfish studies
from the past. In the Haringvliet estuary, two or
more peaks in 0 year-old cockles were measured
on several occasions.
In the Haringvliet, the natural variation is great
and there are changeable conditions in terms of
the weather (wind), temperature and the ratio of
fresh and salt water. It probably does not matter
too much to cockles when the greatest quantity
of edible is available (spring peak in algae),
because there are several cohorts a year.

Yvonne van Kruchten
A probabilistic analysis of the ecological
effects of sand mining for Maasvlakte 2
With her final thesis at the TU Delft, Yvonne van
Kruchten won, among other things, the Risk
Management Study Award 2008. The jury report
states: “With ‘A probabilistic analysis of the
ecological effects of sand mining for Maasvlakte 2’,
Ms Van Kruchten questioned the results of the
EIA through in-depth research into the consequences
of the sand mining for the complex food
chain of sea ducks. By drawing attention to the
uncertainty regarding possible effects of the sand
mining on the food chain with the aid of a large
number of probabilistic analyses, she showed that
the chance of the number of sea ducks declining
due to the sand mining related to Maasvlakte 2
was extremely small. An aid for the government
in modifying its policy.”
She also won the VBKO Hydraulics Prize 2008.
The jury:
“With her probabilistic approach, Yvonne van
Kruchten provides new insights into the design
and results of EIA studies. The results blaze
a trail for the evaluation of potential future
projects impacting the environment. The jury
decided that this result provided a good
impetus for an alternative method of analysing
the environmental consequences of a project
in a scientific manner.”
27

What underwater noise do the dredgers which sail backwards and forwards
to extract sand for Maasvlakte 2 make? Can the noise production per ship
and per activity be ascertained? And what effect does the underwater noise
have on the marine life?
4.Monitoring underwater noise
Human activity in the North Sea has increased in the
past few decades. The ocean-going vessels sailing
there, the construction of wind farms in the sea and
the dredging in sand extraction areas off the coast
produce underwater noise. Marine animals, such as
porpoises, seals and fish, are highly dependent on
sound, certainly if visibility is poor. They use sounds
for orientation and navigation, for communication
with members of the same species and for tracking
their prey. Underwater noise caused by human
activities undoubtedly has an effect on creatures
which live in the sea, but little is known about the
conditions under which this can cause temporary
or permanent damage to animals. There is great
interest in underwater noise among scientists and
knowledge is increasing rapidly.
29

30
Noise production per dredger
and per activity
The Monitoring Plan Construction Maasvlakte 2
covered underwater noise. The task of the government,
as stipulated in the Permit under the Earth
Removal Act, was to determine the noise production
of the sand extraction with trailing suction hopper
dredgers. This had to result in quantitative data
on the noise production per ship and per activity
throughout the dredging cycle: this concerns the
noise made by extracting sand at sea, sailing with
a full hold, unloading at the dumping site and the
return of the empty ship to the sand extraction site.
Effect on marine life?
After measuring the underwater noise, a start
could be made on answering the following
questions, which were included in the competent
authority’s Monitoring and Evaluation Programme
Construction (MEP Construction): Can the underwater
noise nuisance during the sand extraction
operations disturb the fish and marine mammals
(seals and porpoises)? Does it influence their
behaviour? Do they avoid the sand extraction
area and its vicinity? And, if so, does that have
an effect on the populations?
On the basis of the available scientific knowledge
on the effect of underwater noise on fish and
marine mammals, it was predicted in the
environmental impact assessment Construction
Maasvlakte 2 that there would be no negative
consequences as long as the noise produced
remained below a certain level.
Baseline measurement
September 2008
To measure and chart the underwater noise
during the construction work, the Port of Rotterdam
Authority called in the acoustic experts from
TNO Sonar and Acoustics. In 2008, TNO made
an initial plan for conducting the measurements
in a scientifically responsible manner.
The opening question was: what is the ‘normal’
underwater noise produced by ocean-going
vessels wishing to enter the port of Rotterdam?
Regular shipping traffic makes a noise 24 hours
a day; every day about 100 ships enter the port
of Rotterdam from the North Sea and almost the
same number travels in the opposite direction.
This means approximately 180 ship movements
a day. This regular background noise (baseline
measurement) was measured before the
dredging operations for the construction of
Maasvlakte 2 took place.
Hydrophones
TNO performed the baseline measurement
between 8 and 15 September 2008. From a ship,
two underwater microphones (hydrophones) were
lowered at a fixed location. These hydrophones
picked up the noise at two depths: two and seven
metres above the seabed. The survey ship lay
at a location close to the future sand extraction
area and where the new land would be created.
The precise spot was agreed in advance.
Round the clock measurements
All underwater background noises were recorded
for a week, 24 hours a day. Of this, six seconds of
every minute were used for analysis. Furthermore,
wave movements, wind speeds, precipitation and
ship movements were registered via the Automatic
Identification System (AIS). TNO correlated all of
the data obtained with the ship movements and
the measured noise.
This baseline measurement gives an idea of the
regular background noise before the dredging
operations began. By repeating the measurements
during the work, the effects of the dredgers can
be determined.

Results of baseline measurement
Most of the underwater noise during the baseline
measurement was produced by regular shipping.
Only high-frequency noise was caused by the wind.
In addition, not only the ships’ engines produce
noise, but also mainly the movement of water
caused by the action of the ships’ propellers.
Cavitation occurs with badly functioning propellers.
Water bubbles (cavities) occur in the water behind
the propeller, where the pressure is lower. If these
bubbles are then surrounded by water with a higher
pressure, they implode. The ensuing shock wave
generates noise.
Acoustic underwater climate
The acoustic climate under water is a complex
affair: there is a lot of noise under water. Rain,
wind, thunderstorms, waves, vortices and
currents all produce noise. But so do ships’
engines, ships’ propellers and human activity,
such as pile driving and dredging. The noise
under water cannot be compared to the noise
in the air. In the air, noise is muffled better due
to the lower density. Under water, noise carries
farther and it travels more than four times faster.
In the air, sound travels at about 340 metres per
second and in the water at around 1,500 metres
per second.
With noise under water, there are differences
between fresh and salt water, between deep
and shallow water, and other factors also play
a role, such as the water temperature and the
noise absorption by different types of ground.
With underwater noise, the sound pressure
level (Pascal) is measured and set against the
frequency of the sound (Hertz). Using special
reference charts, this can be converted into
a sound level in decibels (dB).
31

32
Measurements during operations
In September 2009, noise measurements were
again carried out at about the same place as the
baseline measurement. Construction work on
Maasvlakte 2 had started and the trailing suction
hopper dredgers were busy.
During the measuring week, seven dredgers
were in operation; this was more than the average
number of ships (five) deployed during the first
two years of construction. The ships present
during the week in question were representative
of all the dredgers used.
The approach route of the ocean-going vessels
to the port entrance had been diverted slightly to
the north due to the dredging activities in the sand
extraction area. However, this diversion did not
cause any problems for the interpretation of the
measuring results.
From sand extraction to dumping
The measurements were carried out in order to
ascertain the noise levels of the various activities
in the entire dredging cycle:
Sucking up the sand in the sand extraction area.
Sailing fully loaded to Maasvlakte 2.
• Unloading the sand via ‘klappen’, rainbowing
and shore pumping. ‘Klappen’ is the unloading
of cargo by opening the bottom doors. Spraying
sand from a nozzle on the bow is referred to
as rainbowing. With shore pumping, the sand is
pushed through a floating pipe and/or underwater
pipe from the ship to the dump site.
• Sailing back empty to the sand extraction area.
With the second measurement, TNO improved
the measuring system. From a survey ship at
sail, measurements were carried out close to the
individual dredgers during the various activities.
In this way, it was possible to record the noise
production per ship and activity. Measurements
were also made via the autonomous system
SESAME, which was anchored at a fixed location
on the seabed.
Measuring results
The noise production of the ships during the
various activities could not be measured directly.
These source levels (source terms) were reconstructed
by TNO from the results of the measurements
via models (models for the propagation of
noise). This is completely in accordance with the
requirements of the Monitoring Plan which was
approved by the competent authority. In addition
to this, the models were used to produce noise
maps for a number of typical points in time, showing,
with the aid of noise contours, how the noise is
distributed around a dredger. The noise contours
are imaginary lines which connect points where
the noise level has the same value. On the maps,
the different noise levels are shown in different
colours. In this way, the maps provide insight into
the noise level at a certain point as well as the
noise distribution.
TNO produced noise level spectra of the under water
noise production of the trailing suction hopper
dredgers during the various phases of the work.
The Port of Rotterdam Authority made the noise
levels reconstructed from the measurements of
representative trailing suction hopper dredgers
available to the competent authority for further
scientific study into the effect of underwater noise
on marine mammals and/or fish.
The execution of the measurements during the
dredging operations went better than anticipated
in the monitoring plan. During the first measurements
in 2009, seven representative ships were
present and all the activities which had to be
monitored took place: ‘klappen’, rainbowing and
shore pumping, and the sailing backwards and
forwards between the sand extraction location
and the construction site (transit). Following
consultation with and approval from the authorities
responsible, all planned measurements for 2009
and 2010 were performed in one go in 2009.
Simulation with swimming
marine mammals
The Port of Rotterdam Authority and TNO are still
busy developing computer simulation models in
which marine mammals (seal and porpoise) swim
through the sand extraction and construction area.
The marine mammals swim from south to north
through the navigation area for 24 hours via
predefined paths. There, they therefore encounter
sailing and working dredgers, the noise contours
for which are available following the 2009
measurements. With what noise level is a seal
confronted? What is the total exposure during
such a swimming route?

As the noise production of regular shipping and
of all sand extraction operations was determined,
it is possible to get a good idea of the total
exposure. The following step is to relate these
results to the dose-effect relationships known
for seals, porpoises and fish. As with humans,
fish and marine mammals are sensitive in varying
degrees to different frequencies of sound.
The sensitivity differs from species to species.
Ships’ noise mainly causes an increase in the
underwater sound with relatively low frequencies.
At these frequencies, seals and fish can hear
more or less the same. Porpoises are less
sensitive at these low frequencies.
However, the audibility of sound does not in
itself determine possible differences in the behavioural
response and temporary or permanent
damage to the hearing. For example, seals can
hear low-frequency sound better than porpoises,
but, due to their curiosity, they are possibly prepared
to tolerate more noise. Almost nothing is
known about the noise levels at which behavioural
changes occur in fish and marine mammals.
This is why the level at which a temporary
change in the hearing threshold or Temporary
Threshold Shift (TTS) occurs is used when
estimating the possible effects of noise from
the dredging operations. Knowledge about
this is also limited, but is increasing rapidly.
Scientific knowledge has increased
On our way to international
standardisation
The measurement of underwater noise and
the source description of underwater noise
during the different dredging operations such
as that carried out by TNO are unique in the
world. Further to the insights acquired from this
research for Maasvlakte 2, the aim is to achieve
the international standardisation of measuring
methods. Ultimately, there needs to be a total
instrument that also describes the effects on
marine life. This would contain knowledge on
the source, the noise propagation in water,
the exposure of animals to noise, the effect
on animals (dose-effect relationships) and
possible measures to mitigate this effect.
Conclusion
In the survey area, the background noise with
the baseline measurement in 2008 was dominated
by (the propellers of) ocean-going vessels at sail.
The underwater noise measured by the fixed
measuring point (SESAME) in 2009 was generally
higher than in 2008 and this is closely related to
the dredgers which passed close to SESAME.
With respect to the dredgers, the underwater
noise is not so much determined by the equipment
switched on for, for example, shore pumping
and rainbowing, as by the activity of the (bow)
propellers whilst sailing and sucking up the sand
(the dredging).
33

Does the land reclamation during
the construction phase influence
the safety and accessibility of the
port for shipping? And what will
be the impact once Maasvlakte 2
becomes operational?
5.
Currents have an influence on the safety of
shipping, certainly in the Eurogeul and Maasmond,
where ships sail into and out of the port of
Rotterdam. During the construction operations,
but also when the new docks become operational,
the flow pattern in the Eurogeul and Maas estuary
must not be allowed to reduce the safety and
accessibility of the port of Rotterdam. The flow
pattern is the speed and the direction of the
Monitoring flow pattern
Maasgeul and Maasmond
current, as well as the changes in this over a short
The rough flow pattern during flood tide is north(east)
erly and during ebb tide south(west)erly. The water
in the Eurogeul is characterised by a complex flow
pattern. The discharge from the Rhine, ebb, flood,
fresh and salt water, as well as a lot of wind, all have
an impact. In the environmental impact assessment,
it was shown, on the basis of research, that the
flow pattern during the construction phase would
not deteriorate. The flow pattern will even improve
with the completion of the seawall, becoming
calmer and less changeable.
Core team Navigation
At the design stage, when the form of Maasvlakte 2
was still on the drawing board, the core team
Navigation was already poring over the flow
patterns of the different variants. For each of the
possible designs, they looked at what influence
these would have on the current.
35

In this way, a responsible and optimum choice
could be made. The core team consists of the
harbour master and representatives of the
Directorate-General for Public Works and Water
Management North Sea, the Rotterdam-Rijnmond
Pilotage Service and the Port of Rotterdam
Authority. During the construction operations,
this core team closely monitored the effects on
the flow pattern. The team is also going to monitor
the effects of cutting through the Yangtzehaven.
Eurogeul, Maasgeul and Maasmond
The Eurogeul or Euro-Maasgeul (sometimes also
referred to as Maasgeul) is the navigation channel
dug in the North Sea which provides access to the
port of Rotterdam. The channel is 57 kilometres
long and 23 metres deep. The last 14 kilometres
of the Eurogeul are called the Maasgeul. In order
to be able to sail into this last section of the navigation
channel to the port of Rotterdam, the ships have to
veer starboard (right). Ocean-going vessels with
a draught of more than 17.4 metres have to use
the Eurogeul, those with less draught only need
to use the Maasgeul. Some 75 kilometres off the
coast, ships which have to use the channel take
a pilot on board, before the start of the Eurogeul.
At the Maasmond, the fairways splits into the
Nieuwe Waterweg to the city and the Caland
Canal to Europoort or the Maasvlakte.
Most favourable design
The effects of currents were already taken into
account at the design stage. When choosing
between the different variants, the design was
tested and improved via flow models and in scale
model studies in various hydrodynamic laboratories
in Europe. The cut-through variant (Yangtzehaven)
and the round, streamlined form were thought to
provide the most favourable flow pattern.
In addition, the location and the form of the hard
seawall were designed in such a way that there
would be no unfavourable effects from currents
in the port entrance. The flow and wave pattern in
the port entrance would even improve as a result.
Improved models and new
measuring methods
Since 2006, extensive research has been carried
out into the prediction of the flow conditions in
and around the port. A flow model was developed,
which can simulate the flow in all phases of the
construction process.
The flow model was improved during the construction
phase and new measuring methods were added.
The flow model developed by the Directorate-General
for Public Works and Water Management forms
the basis. This government department continuously
carries out measurements of the flow pattern in the
Maasgeul. Pilots make use of the information system
FEWS (Flood Early Warning System), which contains
forecasts on water level, flow, wave and weather,
among other things.
Water flow measuring pole
The currents in the access channel are monitored
continuously using a fixed water flow measuring
pole. This device measures the flow in the whole
water column. The data from the fixed water
flow measuring pole for the period from 2002 to
31 October 2011 has now been analysed. It has
shown that the speed of the current at right angles
to the Maasgeul decreased in 2009. This is good
for ships wishing to enter. They are driven less
to the north, as it were.
Radar
By way of extra monitoring, a pilot project was
set up to look at whether the current flow pattern
could also be visualised using the fixed radar
post with the processing system SeaDarQ on
the current Maasvlakte.
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38
SeaDarQ measures the current on the basis of the
wave patterns. The echoes from the waves can
be used to calculate the flow velocity. This can be
done to a depth of two metres below the surface.
It transpires from the pilot project that this system
produces reliable results. For example, the current
seam in the flood phase, important for pilots, can
be derived from the SeaDarQ radar measurements.
A current seam (tidal seam) can often be seen as
a line of foam on the surface of the water. Due to
differences in the density of two adjacent bodies
of water masses, a current arises on the surface
in the direction of the boundary between the
water masses. As a result, floating material and
air bubbles are carried to this boundary, creating
a current seam.
Survey ships
The flow model was validated with field measurements
taken in and around the Maasmond. From
March 2009 onwards, the flow pattern was measured
every four weeks by a survey ship. During a tidal
cycle (ebb and flood, about 12.5 hours), the survey
ship sailed backwards and forwards in the access
channel to validate the models.
The ship measured the flow direction and velocity,
and the salt content in the water column. The
measurements were made using an Acoustic
Doppler Current Profiler (ADCP). The ADCP is
a sort of sonar, which measures the current
right down to the bottom below the ship.
Pilots’ observations
During the construction operations, pilots reported
any peculiarities and indicated where the current
seam was located.
The Port of Rotterdam Authority developed a new
web application specially for the pilots, in which data
from the fixed measuring device and the radar is
made available via the Internet. As a result, the pilots
always had the most up-to-date information on hand.
Measurements and model
During every phase of construction, the shape
of the land reclamation at that time was put into
models and the cross current and variation within
this were evaluated.
The comparison between the measurements and
the results from the models showed that, generally
speaking, the model made a good prediction of
both the flow direction and the flow velocity.
Conclusions
The safety and the accessibility of the port of
Rotterdam for ocean-going ships have increased.
The cross current velocities in the approach
channel have been deflected: they veer more
towards the coast than prior to the construction
of Maasvlakte 2. This levelling off is favourable for
incoming and outgoing ocean-going ships. This is
in line with the predictions in the EIA Construction.
Direction
The flow direction of ebb and flood currents at
the fixed measuring set-up has shifted slightly
as a result of the construction of Maasvlakte 2
and the seawall.
Speeds
The maximum cross current speeds in the Maasgeul
have decreased substantially in comparison with
the period 2002- 2010. This decrease falls outside
the established natural range and can therefore
be attributed to the construction of Maasvlakte 2.
The change in cross current velocity is the result
of, among other things, the change in flow direction,
considering that the current is increasingly following
the direction of the channel rather than the coastline.

‘Piloting is safer and more predictable’
Rik van Marle, registered pilot with Rotterdam-Rijnmond Pilots Corporation
Model, measuring pole and radar
Under normal conditions, the flow patterns are predicted
well by the flow model in FEWS. The actual
flow pattern is in keeping with the expectations of
the models. The measurements from the water
flow measuring pole produce reliable values at the
Maasmond and can be used in FEWS to test the
reliability of these model predictions. The position
of the current seam in the flood phase can be derived
well from the SeaDarQ radar measurements.
Pilots sometimes encountered two or three current
seams. Following investigation, this was shown to
involve superficial current seams, with no or hardly
any changes in the water flow. These current
seams were probably the result of construction
operations.
‘I have been part of the Core Team Navigation
Maasvlakte 2 since 2008, on behalf of the
Pilotage Service. We have been able to use
our knowledge and experience in evaluating the
designs. We were also kept up to date on every
phase during the sand extraction at sea and the
construction off the coast, and we were able to
provide feedback on what we came across.
Important, because we pilots know the area like
the back of our hand and we are the eyes and
ears at sea. What matters to us is to get ships
into the port quickly, safely and without incident,
whether or not they are working on Maasvlakte 2:
our piloting work may not be interrupted and it
must not hinder us in any way. Everything went
extremely well: there was not a single incident,
even when the dredgers were most active.
The construction was phased. By first creating
an island off the coast, it was possible to
minimise the influence of undesirable currents.
I am extremely positive about the
change in the flow pattern
The cross current effect, which could be quite
severe in the old situation, has levelled out.
The angle between the current and the sailing
direction has become smaller. The flow has now
been guided more in the direction in which the
ships sail. The undesirable effects due to the
sharp gradient when passing the current seam
have been minimised: the chance of unexpected
movements is smaller as a result. This really is
a big improvement, and piloting is safer and
more predictable.’
39

How does the Port of Rotterdam Authority handle historical finds
in or on the seabed? What have the archaeological investigations
yielded in the sand extraction area, in the sprayed-on sand on the
soft seawall and when deepening the Yangtzehaven? And what
happens to palaeontological finds?
With the construction of land in the sea, the
Valletta Treaty (1992) makes it compulsory to look
for historical objects in or on the seabed. In the
Netherlands, this led, in 2007, to the (revised)
Archaeological Heritage Act (Wamz). The starting
point of this act is to preserve archaeological sites
as much as possible by sparing them or, if that is
not possible, by excavating them. Guidelines for
this are contained in the act.
archaeology
and palaeontological finds
6.Monitoring
In this connection, the Port of Rotterdam Authority
and the Cultural Heritage Agency of the Netherlands
(RCE) signed an Archaeology agreement. This
contains the agreements with contractor PUMA.
Implementation protocols state how archaeological
finds must be treated during the construction
ope rations. Within 24 hours of an archaeological
find, the contractor must inform the Port of Rotterdam
Authority and RCE. The archaeology committee,
in which the RCE, the Port of Rotterdam Authority,
the Bureau Oudheidkundig Onderzoek Rotterdam
(BOOR) and PUMA are represented, then decides
what will be done with it.
41

2
1
3
42

Areas
The archaeological investigation for Maasvlakte 2
started in 2004. Following a desk study of academic
publications, it was decided where the investigation
should focus:
1. The location where Maasvlakte 2 was to be built.
2. The sand extraction area about 10-15 kilometres
off the coast to the southwest of the Maasvlakte.
3. The place where the Yangtzehaven was to be
widened and deepened.
Maritime archaeology
Before the start of the construction work, the seabed
of the sand extraction area and the construction area
were investigated. Using sonar equipment, a search
was made for objects of historical importance and
in particular shipwrecks or parts thereof. During
this investigation, 94 observations were made,
which finally led to 9 possible sites of historical
wrecks. At these spots, divers looked for anything
of archaeological value. At one location in the
construction area this resulted in an archaeological
investigation. A wooden shipwreck from the
19th century was excavated.
The contours of the sand extraction area were
modified on the basis of research, so that another
shipwreck could be preserved. This location was
monitored during the project.
Archaeologists look for man-made objects
(artefacts). These can help them form a picture
of how people lived in the past: their domestic
situation, how they conducted trade, hunted,
ate and what rituals they had.
Palaeontology: ‘bycatch’ for
science and the public
There are no legal obligations regarding
palaeontological finds. Despite this, the Port
of Rotterdam Authority decided to handle any
palaeontological finds, such as bones and fossils,
with care during the dredging operations. Also
because geologists and archaeologists can gain
new insights into the submerged landscapes and
their possible inhabitants on the basis of these
finds. During various Ice Ages, the sea level was
so low that what is now the North Sea was dry.
This respect for the past led to a covenant with
the Natuurhistorisch Museum Rotterdam, which
was signed on 16 February 2010.
The Port of Rotterdam Authority ensures that all
bones from mammoths and other fossil mammals
found during the sand extraction on the bed of the
North Sea go to the Natuurhistorisch Museum
Rotterdam. Thanks to the meticulous records kept
by the contractor, the ‘exact’ sand extraction locations
and depths are known for all the finds. Partly as a
result of this, the new material is of great scientific
value. The palaeontological objects are accessible
for scientists and the public; they are exhibited in
the Rotterdam museum referred to above, but also
in the FutureLand information centre.
Palaeontologists study the past on the basis of
fossil remains, such as teeth, bones and vertebrae,
or traces of plants and animals. They are interested
in such things as their origins and relationship with
plants and animals living today.
43

44
Archaeology, palaeontology and
geology in sand extraction area
Cold Serengeti in the North Sea
The bed of the North Sea is a rich and internationally
important underwater site for prehistoric fossil mammals.
Until about 10,000 years ago, the southern
North Sea basin was dry and formed an expansive
cold steppe, referred to as the Mammoth Steppe.
It was inhabited by woolly mammoths 100,000 to
25,000 years ago, along with rhinos, steppe wisents,
hyenas, reindeer and Irish elk etc., as well as many
other smaller mammals.
Two hundred mammal remains
During the sand suction operations, a number
of larger objects were caught in the ‘bomb grate’
of the drag head, including palaeontological finds.
As a result, the Port of Rotterdam Authority decided
to organise specific fishing trips for palaeontological
finds in the sand extraction area. In October 2009,
the cutter OD7 spent two days fishing for finds.
In 2010, the Jade (BRA-7) was used to fish for
mammoth fossils and archaeo logical finds on six
Saturdays spread through the year. Thanks to the
suction dredgers, which kept exposing new and
deeper parts of the seabed, the fossil finds in
particular were spectacular: over two hundred topquality
mammal remains, such as teeth, vertebrae
and bones, have now been added to the collection
of the Natuurhistorisch Museum Rotterdam. Three
quarters of the finds are from the woolly mammoth
(Mammuthus primigenius), including the longest
mammoth thighbone (as yet) found in the North
Sea, two virtually complete and exceptionally large
pelvic bones and a tusk.
Other animal species from the Late Pleistocene
the fossils of which were dredged up from the sand
extraction area are reindeer, steppe wisent, aurochs,
Irish elk, red deer, woolly rhino, wild horse, cave
lion, harp seal and otter.
In October 2009, a 133 centimetre long thighbone
of a woolly mammoth was dredged up. This is the
largest fossil bone ever found in the Netherlands.

Hyena pellet
On 18 August 2010, the BRA-7 dredged up
the first fossilised hyena pellet ever found in the
Netherlands. Research in the Natuurhistorisch
Museum Rotterdam revealed that the light brown
fossilised dung had been produced an estimated
30,000 to 40,000 years ago by a cave hyena
(Crocuta crocuta spelaea). The perfect fossilisation
of this relatively young (Late Pleistocene) piece
of hyena excrement is exceptional. The so-called
coprolite, measuring 55x44 millimetres, has been
incorporated into the museum’s collection and is
now exhibited there.
The presence of this predator had previously
been demonstrated by dredged-up fossilised
skeleton parts and, most importantly, by typical
signs of a hyena having fed on (mammoth) bones.
Geological envelope
In 2011, the specific searches using the BRA-7
were repeated in the summer (week 23). The
design of this palaeontological search differed from
that of the earlier fishing trips. In advance, previous
results (finds) were looked at in combination with
the geological structure of the slopes (of the sand
extraction pit) along which they would search.
During these fishing trips, a Side Scan Sonar (SSS)
was used. Use was also made of a shallow seismic
profiler (xStar) and a Boomer (sparker).
The SSS is used to look sidewards along the
seabed for objects which protrude partially from
the bed. With the xStar and the Boomer, one can
look in the bed at the structure of the substrate.
Furthermore, a number of depthwise overlapping
seismic borings were carried out perpendicular and
parallel to the slope. Using this data, the geological
structure of the pit was mapped out and, with the
aid of samples from the borings, the age of the
various differentiated layers is ascertained. In this
way, the (previous) finds from the fishing trips can
be placed in their geological context. During the
fishing trips, the catches from the two bottom trawl
nets were looked at systematically and sorted into,
among other things, bone material, flint, stone,
gravel, fossil shells and wood. Also, a general
characterisation was given of, for example, the presence
of lumps of clay, chunks of peat, residues of
wood and the quantity of serpent stars and starfish.
Submerged landscapes
The North Sea is the second largest mammoth
graveyard, after Siberia. It concerns the middle
and last part of the Old Stone Age, the period
before 9,700 BC. We now know, partly from the
flints and tools found, that people roamed the
cold steppe (what is now the seabed).
It is important to know if the bones found can be
connected with the landscape research in the sand
extraction area. The scientists, including physical
geographers and geologists, were interested in the
piling up (sequences) of landscapes. As a section
of the bed of the North Sea was dug up in the sand
extraction area to a maximum depth of 20 metres
below the original seabed, the composition of the
layers could be determined and dated (dating study).
Furthermore, they wanted to be able to make a
reconstruction of the landscape sequence. The
reconstruction study would supposedly produce
unique scientific knowledge: a lot of dredging has
been done in the North Sea, but never before was
research conducted on such a scale.
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46
Dating sand layers
In the slope of the north-eastern edge of the sand
extraction area, borings were performed systematically
in the successive soil layers, whereby the
coordinates and the depth of each drilling location
were carefully noted. Under the guidance of
TNO | Geological Department, the age of the
(sand) layers is determined via OSL dating and
the sediments are carefully analysed. OSL stands
for Optical Stimulated Luminescence and is a
relatively new dating technique. Some minerals
emit a small light signal when they are heated or a
light is shone on them. This light, or luminescence,
can be used to date sediments, pot fragments and
a number of other artefacts. Luminescence dating
has a longer measuring range (250,000 years) than
the commonly used C14 or carbon dating method
(approx. 50,000 years). The datings are now being
conducted in the OSL laboratory of the TU Delft
(reactor centre).
Puzzle: walking whale or swimming
mammoth?
Palaeontological research on the whale and
mammoth bones dredged up using the popular
C14 dating method produced a striking result:
both heavyweights apparently lived in the same
place between about 32,000 and 38,000 years
ago. Shells were also dated to about the same
period. But did the whales live on the land then
or the mammoths in the sea?
The method for dating shell and bone material
of this age found underwater must be revised
slightly. New carbon material is added through
the recrystallisation of calcium in shells and
bones by bacteria which live in this porous
material. Due to this ‘contamination’ with young
carbon, the C14 method is not accurate with
material more than about 30,000 years old.
By studying the sand in which the finds were
made via the OSL dating technique, it will shortly
be possible to date the material more accurately.
Archaeology and palaeontology
in outer contour
The freshly created beach of Maasvlakte 2
was studied before it was opened to the public.
The beach was cleaned systematically, and
archaeological and palaeontological finds were
safeguarded mechanically and manually for
scientific study. This involved collecting smaller
remains from the Holocene and Pleistocene.
It is already clear that many remains of animals
from the mammoth group from the Pleistocene
and archaeological artefacts from the Late
Pleistocene and Holocene have been found.

Finds include teeth from a white shark, a beaver
and a rhinoceros. A lot of unique fossil shells were
also found, and a large number of fossil marine
animals and flints. Some remains proved to be
between 50,000 and a million years old. The white
shark tooth must definitely be a couple of million
years old. The shells could help with the reconstruction
of the landscape. Furthermore, the shells
provide indications of the origin, i.e. brought in from
the north or south by ice sheets or rivers. Scientists
are now busy investigating how old the shells are.
The Pleistocene lasted from 2.588 million to
11,700 years ago and is subdivided into five more and
less cold Ice Ages and warmer periods in between.
The Holocene is the geological period from
11,700 years ago to the present. The warming up
of the earth caused the ice caps, which covered
areas such as Canada and Scandinavia, to melt.
As a result, the sea level rose all over the world,
with the formation in Western Europe of the North
Sea and the Irish Sea, among other things.
River Scheldt in the Netherlands
The first studies of the shells found have now provided
the scientific proof for a long-held assumption:
the Scheldt once flowed further northwards and
came out in the Rhine in the vicinity of the sand
extraction area for Maasvlakte 2.
Archaeology and geology in the Yangtzehaven
In order to make the new docks of Maasvlakte 2
accessible for ocean-going ships, the Yangtzehaven
must be widened, deepened and dredged through
in 2012. The current bottom (-17 metres NAP) will
be dug almost five metres deeper. This is the floor
on which hunters and gatherers once hunted and
lived in temporary encampments in the Middle
Stone Age (from about 11,700 years ago). The area
from the North Sea to beyond today’s Rotterdam
once formed part of a large river delta that was rich
in food, with river dunes and more low-lying channels.
The river dunes, also referred to as ‘donken’, were
high, dry spots in the wet river delta. These river
dunes were ideal places to spend the night and
live on a temporary basis.
What new knowledge about these people and their
way of life are we gaining from the archaeological
excavations on the floor of the Yangtzehaven?
What do the archaeological remains tell us and
what is the structure of the floor like?
Unique archaeological
underwater research
In the Yangtzehaven, systematic research was
carried out on the buried former land surface and
the possible traces of human habitation for the
first time in the Netherlands at this depth (about
-20 metres NAP) and so far to the west. The layers
had remained undisturbed in the substrate.
The research was conducted at a water depth of
around 17 to around 5 metres below the bottom of
the port. On the basis of existing borings, seismic
measurements and probes (rough exploration of
the soil composition via a rod with a sensor that
measures resistance and friction), an area of
approximately 120 hectares was charted. Of the
three ‘archaeologically promising’ zones which
emerged from these initial investigations, two were
looked at in more detail: a buried river dune (donk)
and a silted-up channel, where people in the past
possibly sailed in their canoes.
These two areas were studied more thoroughly
by means of highly detailed seismic research
and vibrocore sampling. On this basis, the
decision was made to excavate small sections
of the buried river dune.
47

natural stone, bone adze (tool used for working
wood) and scrapers (skins) had already been
48
Prehistoric habitation on
river dunes
The river dunes are visible in the drill cores. That
is one of the most important results up to now.
The structure of the soil consists of a thick layer of
North Sea bed, made up of sand and shells. Below
this, there are layers of clay and peat. Under the
peat lies the river dune, the top of which is recognisable
from dark, rough-grain sand. This means that
sections of the old bed, on which people walked in
the Stone Age, are still intact and well preserved.
This allows us to form a good picture of this period.
Where the North Sea and the port of Rotterdam
now lie, there was a fluvial landscape formed by
the Rhine and Maas 9,500 - 9,000 years ago.
The rich flora and fauna made this fluvial area
attractive to hunters and gatherers. In the Middle
Stone Age, these hunters and gatherers lived in
families, in small groups of about ten people.
They moved through the region, with the higher
river dunes (donken) serving as ‘camping sites’,
as they were safe from floods there. There was
also sufficient food in the area, such as fish, meat,
berries, nuts and fruit. The excavations are providing
us with more information on their way of life.
Creation of river dunes
During the last Ice Age, 100,000 to 11,700 years ago,
it was bleak and cold. During the coldest period,
between about 25,000 and 15,000 years ago, the
landscape was bare, with sparse vegetation. The
strong winds blew the sand on the surface away
and deposited it elsewhere. During the Ice Age,
the Dutch rivers were of the twisting type: they often
changed their course, as a result of which they
had a wide bed which was only completely covered
with water in spring, when the snow melted. In the
summer and autumn, the bare bed was largely
dry. The sand on the surface, just like the surface
sand that was blown across the Netherlands at the
time, could be picked up by the wind and deposited
elsewhere. Right next to the bed, there was some
vegetation at a number of places, in which the sand
became trapped. In this way, relatively high dunes
(donken) were created, where people could live
safely later, when the climate became less harsh.
Finds from hunters and gatherers
The material from the Yangtzehaven was sieved
and archaeologists are currently studying these
sieved remains. Shortly after the start of the
research, some 18,000 small remains of charcoal,
wood, bones, burnt bones, fish, (worked) flint,
found. These remains suggest that people
inhabited the river dune.
The bone remains are small particles, no bigger
than 1 cm, burnt and unburnt animal bone.
The unburnt bone demonstrates the presence
of animals in the area. The burnt bone is burnt
in such a way that it must be the result of human
action. Together with the charcoal found, this is
an indication of food preparation, such as the
grilling of meat.
The flint fragments and the minuscule splinters
of flint prove that flint was worked in situ to make
implements, such as arrowheads, knives and
scrapers for cleaning animal skins.
The unique thing about the site in the Yangtzehaven
is that it is the first time in the Netherlands that a
complete package of material of this age has been
found. There are known sites in the Netherlands
where flint of this age has been found in these
Pleistocene soils, but the organic material (wood,
berries, etc.) was always missing because it had
decayed through time. Here, everything can still
be found together and that yields new knowledge
about how the people at the time lived.

River plain with sandsbanks
and braided river
River dune
Reconstruction of Stone Age fluvial area
The soil borings and the samples obtained from
these, combined with all the other field studies and
measurements, provide the researchers with a
detailed picture of the substrate. In the laboratory,
the soil samples are examined further, for example
to work out from pollen (palaeo-botanic study) what
plant growth was like in the past. In the meantime,
Deltares has made a model of the dune and, in
information centre FutureLand, a reconstruction of
a camp gave visitors an idea of life in the Stone Age,
during the themed weekend in February 2012.
Bedding sediment
Older subsoil
49
Submerged landscapes charted
Henk Weerts, senior researcher in Physical Geography and
Palaeontology with the Cultural Heritage Agency of the Netherlands
The unique samples from the sand extraction
pits enable us to perform dating research
and make geological reconstructions of the
landscape, so that we can study the sequence
of landscapes. By combining this with the
archaeological and palaeontological finds,
the picture of the Stone Age is completed.
The area where the Yangtzehaven now lies was
inhabited by humans in the Middle Stone Age
(8,800 - 4,400 B.C.). At a depth of 20 metres in
a river dune, the archaeological study found
traces of bone, flint and charcoal. This organic
material was buried quickly and covered with
water, and excellently preserved.
These finds date from about 7,500 - 7,000 B.C.,
providing the first scientific proof that people
lived at this spot in the Early and Middle Stone
Age. Up to now, very little was known about
this period so far west in the Netherlands.
What happened here is unique: the depth,
the techniques and the finds.
We are able to form a three-dimensional image
of the submerged landscapes and what life
looked like there. The finds and method have
been presented internationally at scientific
conferences both at home and abroad. The
project as a whole has already led to various
scientific publications in the field of archaeology,
underwater archaeology, palaeontology and
landscape reconstruction.’

Although the first phase of the construction of Maasvlakte 2
will be completed in mid-2013, a number of things will continue
to be monitored. The development of the erosion pit is an example
of this. Furthermore, monitoring for a number of themes related
to the existence of Maasvlakte 2 will start. An example of this
is the development of the deep and shallow foreshore of the
land reclamation.
In 2012 and 2013 too we will be looking at the monitoring
results in relation to the predictions made in
the EIA. It transpires from the results already known
that the consequences and effects remain within
the EIA predictions. This is cause to continue to
evaluate the format of the monitoring critically in the
coming two years. As a result, changes to studies
are conceivable or even the termination of certain
measurements. After all, the main purpose of the
monitoring programme is to gather enough reliable
information to determine whether or not the effects
fall within the preconditions set in the permits granted.
7.
The permit-granting agencies will evaluate this in
the course of 2013. The monitoring results which
the Port of Rotterdam Authority has supplied to these
competent authorities in the past few years play an
important role here.
51
To be continued...
The following edition of the Maasvlakte 2 Monitor
is expected to be published in 2014. In it, we will at
all events bring you up to date on the results of this
evaluation of the monitoring results.

Silt Profiler
Measuring platform for monitoring survey at sea
Colophon
Publication
Port of Rotterdam Authority
Project Organization Maasvlakte 2
www.maasvlakte2.com
info@maasvlakte2.com
September 2012
Content and editing
Tiedo Vellinga, Paul van der Zee,
Gert Hardeman (text)
Images
Port of Rotterdam Authority
Design
Port of Rotterdam Authority
Production and finish
Platform P
Central core With power
supply and communication:
including WIFI equipment
Niskin bottle (water sample)
1x high position
Niskin bottle (water sample)
2x low position
Optical Backscatter Sensor
(OBS)
Measures concentration of
particles in the water through
the reflectance of light emitted
ACS Wetlab sensor
To measure the colour of the
water (complete frequency
spectrum of light)
FRAME
Diameter: 0,80 m
Height: approx 1,20 m
Total weight: approx 80 kg
Pressure sensor
To measure depth vis-à-vis
water surface
More information
Visit the FutureLand information center
www.futureland.nl
Fluorescence meter
Emits light and measures the
fluorescence of chlorophyll this
causes and the chlorophyll
concentration (algae)
LISST
To determine granular distribution
of particles in the water column
CT (conductivity, temperature)
This is also used to determine
the salinity
Altimeter (echo sounder)
Measures the distance to
the bottom; also used to close
bottle at certain height vis-à-vis
the bottom
Flow velocity meter
Measures the speed of the water
in 3 directions in a volume 15 cm
below the probe