Report To: Lakeland Marine Ltd

AMSL Report No 10/04.6 rev1
July 2010
BDnC
site and hydrographic survey report
ANDERSON MARINE SURVEYS LTD.
Croabh, Tighnabruaich,
Argyll. PA21 2DY
Tel/Fax: 01700 811677
Email: amsl@sol.co.uk
Report To: Lakeland Marine Ltd
Issued By: SJA
Date: 06 July 2010
BDnC – site and hydrographic survey report – rev1
Introduction
This report describes a site and hydrographic survey of the Bagh Dail nan Ceann (BDnC)
cage site, outer Loch Melfort in Argyll.
Current data acquisition was carried out by Angus Matheson, Matheson Consulting. Data
analysis has been carried out by AMSL in accordance with SEPA guidelines (Regulation and
monitoring of marine cage fish farming in Scotland - a procedures manual. Attachment VIII
Site and Hydrographic Survey Requirements. Version 2.7, 31 October 2008).
This revision (rev1) addresses various issues raised by SEPA on the draft report (rev0),
principally in relation to selection of depth bins for near-bed and sub-surface levels.
Site description
The site is located south of the
entrance to Loch Melfort.
Within the area to be modeled
using AutoDepomod, the
seabed slopesgenerally to the
west to depths >50m,
although the grid area is
influenced by a shoal
extending south from Culbhaie
rocks.
5km
General location of survey
AMSL Report No 10/04.6 rev1
July 2010
BDnC
site and hydrographic survey report
Survey program
The deployment position was 56° 10.778’ N 05° 35.307’ W, OSGB (1936) 177394 704357.
The deployment of 43.5 days at 20 minute duration was longer than a half-lunar period (15
days) from 18:00 UTC on the 12 March 2007 to 07:00 on 25 April; accordingly, a
representative 15-day period has been selected (commencing 09 April 2007; 1081 records).
Additional bathymetric data, as required by the updated guidelines, was also acquired
subsequently on 30 March 2010.
A simultaneous anemometer deployment was carried out to ensure that the period of
observation included at least 2 consecutive days with wind speeds of less than force 5
(<10m/s ). The anemometer and wind direction gauge were deployed 19.6km to the south at
Achnamara, 56° 03.070’ N 05° 33.396’ W.
Methods
Positioning for the survey was provided by a Lowrance GlobalMap 100 GPS receiver, with at
least seven satellites visible. GPS precision was checked against a land reference point
(Craobh Haven west breakwater 56° 12.808’ N 05° 33.559’ W) prior to, and on completion of
the survey. These differed by 0.003’N, 0.001’W (5.6m). Positions were recorded as
geographical coordinates in WGS84 datum.
Depth at the mooring location and additional reference points was recorded using an
echosounder (resolution 0.1m). Recorded depth was corrected to chart datum using tidal
height predictions, from WXTide (Oban, corrected to Loch Beag) for 2007 data and Belfield
Software Tide Plotter v5.5 (Loch Melfort) for 2010 data. Positions were converted from
geographic to OSGB coordinates (same datum) using DatumPro v1.1 software.
To produce the site survey figure, bathymetric data digitised from Admiralty Chart 2326 have
been re-contoured using the gridding routine within Surfer. Selected spot depths from the site
survey are also shown (for clarity, not all depths are labeled).
Hydrographic data were collected using a Nortek Acoustic Doppler Profiler (NDP, serial
number 4705), 0.5MHz, deployed 0.55m above bed. Data from 51 bins at 1m spacing were
recorded. Meter specifications and configuration where available are shown below:
accuracy
speed
±1%, ±0.5cm/s
precision
resolution
0.1 cm/s
range
0-10 m/s
AMSL Report No 10/04.6 rev1
July 2010
BDnC
site and hydrographic survey report
The deployment log showing instrument configuration (the .CTL file extracted from the raw
.ADP file) is reproduced below:
File ----------------------> bdnc4001.ADP
FileSize (bytes) ----------> 2139136
Number of profiles --------> 3136
Time of first profile -----> 2007/03/12 18:00:00
Time of last profile -----> 2007/04/25 07:00:00
NDP Hardware Configuration
---------------------------SoftwareVerNum ------------> 2.6
SerialNumber --------------> N4705
NdpType -------------------> 3000 kHz
Nbeams --------------------> 3
VertBeam ------------------> NO
SlantAngle ----------------> 25
SensorOrientation----------> UP
CompassInstalled ----------> YES
RecorderInstalled ---------> YES
TempInstalled -------------> NO
PressInstalled ------------> YES
Transformation Matrix -----> 1.540 -0.771 -0.771
-----> 0.000 -1.334 1.334
-----> 0.359 0.359 0.359
NDP User Setup
---------------DefaultTemp ----- (deg C) -> 8.00
DefaultSal ------ (ppt) ---> 33.00
DefaultSoundSpeed (m/s) ---> 1479.90
Ncells --------------------> 50
CellSize -------- (m) -----> 1.00
BlankDistance --- (m) -----> 1.00
SensorDepth ----- (m) -----> 0.00
TempMode ------------------> 1
PingInterval ---- (s) -----> 0.00
AvgInterval ----- (s) -----> 320
ProfileInterval - (s) -----> 1200
BurstMode -----------------> DISABLED
BurstInterval --- (s) -----> 1200
ProfilesPerBurst ----------> 1
CoordSystem ---------------> ENU
OutMode -------------------> AUTO
OutFormat -----------------> BINARY
RecorderEnabled -----------> ENABLED
RecorderMode --------------> NORMAL
DeploymentMode ------------> ON
DeploymentName ------------> BDNC4
AMSL Report No 10/04.6 rev1
July 2010
BDnC
site and hydrographic survey report
Depth bins have been selected according to current SEPA guidelines:
•
Sub-surface – from a depth 5m below the lowest predicted spring tide during the
deployment period
•
Cage-bottom – at a depth corresponding to the bottom of the cages at mean sea level
±1m
•
Near-bottom – as close to the bed as practicable
Cell heights calculated as transducer height (0.55m) + blanking distance (1.0m) + cell number
x cell size (1.0m) are:
measured depth at deployment (m)
predicted tidal height at deployment (m)
corrected depth at deployment (mCD)
41.0
1.8
39.2
lowest predicted tide during deployment (mCD)
0.4
charted mean sea level (Loch Melfort) (mCD)
1.4
mean sea level height above bed (m)
assumed cage depth (m)
41.0
15
bed - height above bed (m)
3.6
Bin 2
mid - height above bed (m)
26.6
Bin 25
surface - height above bed (m)
33.6
Bin 32
bed - depth below MSL (m)
37.4
mid - depth below MSL (m)
14.4
surface - depth below MSL (m)
7.4
Data were extracted as time series from the raw data file using the Nortek utility Explore ADP
v1.10. Extracted data were analysed using the SEPA tool HGdata_analysis_v7, running in
Excel. Graphs were re-formatted to allow co-presentation of data from all three depth bins.
The data record was truncated to 15 days, 1081 records as described above.
A grid convergence of 2.98ºW (source: HGdata_analysis_v7) and Magnetic Declination of
5.28ºW (source:http://www.ngdc.noaa.gov/geomagmodels/Declination.jsp) applied at the time
of survey and were applied in HGdata_analysis_v7. Reported summary statistics are in ºG.
Site survey results
The site survey and bathymetry diagram is shown below.
RCM position and spot depth information is tabulated below.
AMSL Report No 10/04.6 rev1
July 2010
Measured
Position
mCD
OSGB36
NGR
NDP
3/12/07
14:00
1.8
41.0
39.2
56 10.778N
005 35.307W
177320
704343
1
3/30/10 9:19
1.6
26.8
25.2
56 11.052N
005 35.117W
177609
704841
7
2
3/30/10 9:23
1.6
31.6
30.0
56 11.031N
005 35.017W
177711
704797
8
3
3/30/10 9:27
1.5
38.0
36.5
56 10.975N
005 35.055W
177666
704695
7
4
3/30/10 9:31
1.5
31.5
30.0
56 10.835N
005 35.131W
177574
704440
7
5
3/30/10 9:38
1.5
36.5
35.0
56 10.787N
005 35.195W
177503
704354
8
6
3/30/10 9:42
1.5
49.2
47.8
56 10.822N
005 35.281W
177417
704424
8
7
3/30/10 9:45
1.4
46.4
45.0
56 10.87N
005 35.218W
177487
704509
7
8
3/30/10
10:00
1.4
32.1
30.8
56 10.996N
005 35.155W
177564
704740
8
Fix duration
(min)
UTC
Depth
# satellites
Predicted tidal
height (m)
label
Date / Time
BDnC
site and hydrographic survey report
704900
25.2
704800
30.0
30.8
704700
36.5
704600
45.0
704500
47.8
30.0
704400
39.2
35.0
704300
704200
704100
704000
NDP
1km box centred on NDP
703900
bathymetric data (30/03/2010)
703800
177900
177800
177700
177600
177500
177400
177300
177200
177100
177000
176900
176800
Site survey figure. All depths in m(CD). Contoured depths from chart data; spot depths from site survey (30 March 2010)
AMSL Report No 10/04.6 rev1
July 2010
BDnC
site and hydrographic survey report
Meteorological Results
Wind velocities (analysed using the SEPA tool HGdata_analysis_v7) had 24h rolling averages
between 1.0 and 3.4 m/s, with no speeds in excess of 10m/s recorded over the selected part
of the deployment period. The deployment period therefore met the requirement for at least
three consecutive days with mean daily wind speed <10m/s.
Hydrographic survey results
Pitch and roll varied during the deployment period from –0.6 to +0.3º and -0.5 to
+0.3º respectively. Pitch and roll were therefore within acceptable limits (15º) for the
instrument.
Summary statistics for individual depth bins are tabulated below:
bed
mid
surface
Number of records
1081
1081
1081
Start date/time
09/04/07 00:00
09/04/07 00:00
09/04/07 00:00
End date/time
24/04/07 00:00
24/04/07 00:00
24/04/07 00:00
Mean velocity (m/s)
0.084
0.083
0.082
Minimum velocity (m/s)
0.004
0.005
0.004
Maximum velocity (m/s)
0.245
0.289
0.288
Ranked percentage of mean velocity
55%
60%
58%
Ranked percentage of 3cm/s
8%
11%
10%
Ranked percentage of 4.5cm/s
21%
24%
23%
Ranked percentage of 9.5cm/s
65%
68%
68%
Residual velocity (m/s)
0.018
0.024
0.022
Residual direction
268 (Deg-G)
246 (Deg-G)
256 (Deg-G)
Major axis
210 (Deg-G)
210 (Deg-T)
210 (Deg-G)
Residual parallel (m/s)
0.009
0.019
0.015
Residual normal (m/s)
0.015
0.014
0.016
Amplitude parallel (m/s)
0.123
0.123
0.119
Amplitude normal (m/s)
0.049
0.052
0.054
Parallel anisotropy
0.62
1.37
0.95
Normal anisotropy
2.50
2.37
2.23
AMSL Report No 10/04.6 rev1
July 2010
BDnC
site and hydrographic survey report
Interpretation
Recorded water depths from the NDP deployment and site survey (30/03/2010) were broadly
consistent with contoured bathymetry derived from chart data. This has been quantified by
extracting interpolated depths for the locations of measured depths from the SURFER grid
used to derive contoured bathymetry (from a combination of chart and measured data), and
calculating %error between measured and contoured values. The analysis indicates errors of
between -43.7% and 21.9%, with a general trend to actual depths being greater than charted
(consistent with shoal bias in charted bathymetry). This systematic discrepancy is considered
acceptable given the relatively steep seabed gradient at this point, and is conservative in
relation to AutoDepomod modelling; the extracted chart data is therefore considered to be
acceptable for modelling purposes.
OSGB E
OSGB N
Measured depth
(mCD)
Contoured depth
(mCD)
% error
NDP
177394
704357
39.2
32.0
-22.5%
1
177609
704855
25.2
32.3
21.9%
2
177711
704811
30.0
29.4
-2.1%
3
177666
704709
36.5
31.7
-15.1%
4
177574
704454
30.0
26.9
-11.5%
5
177503
704368
35.0
24.4
-43.7%
6
177417
704438
47.8
36.2
-32.0%
7
177487
704523
45.0
42.9
-4.9%
Following advice from SEPA FFModelling (17 June 2010), the near-bed bin (1) has been
rejected as having insufficient predicted horizontal precision, and the sub-surface bin (34) as
compromised by side-lobe interference; these bins have been replaced by bins 2 and 32
respectively.
In general, there was similarity between recorded current velocity and direction at all depths.
Velocities were moderate, with a maximum recorded surface velocity of 0.288m/s. Currents
were moderately directional, with the major current axis orientated parallel to bathymetric
contours.
There is also clear evidence of spring-neap variation consistent with predictions, and no
evidence of discontinuities or data artefacts during the selected part of the deployment
(although the earlier part of the deployment was apparently influenced by a wind-related surge
between 16 – 20 March 2007).
AMSL Report No 10/04.6 rev1
July 2010
BDnC
site and hydrographic survey report
Residuals shown by cumulative current vectors were moderate at all depths. The residual
direction was orientated down-slope at all depths.
The recorded data are indicative of a moderately flushed site.
Quality Assurance statement
The data described above are considered to be representative of the flow conditions at the
location.
Dr SJ Anderson
Anderson Marine Surveys Ltd.
06 July 2010
BDnC_subs_33.6m_bin32
Current meter ID :
declination:
Period of measurement :
-5.280
convergence:
9/4/07 00:00
0 hrs
0 mins
0.35
0.3
Percentile Analysis
thresholds
90%
0.4
major axis 210
mean
percentile analysis
8.61
7.18
5.59
0.25
0.2
0.15
100%
Max:
Mean:
Min:
Depth/
Pressure
(Deg-G)
0.1
0.013 m/s
0.023 m/s
0.030 m/s
0.048 m/s
0.074 m/s
0.108 m/s
0.147 m/s
0.174 m/s
0.238 m/s
0.288 m/s
0.030 m/s
0.045 m/s
0.095 m/s
0.082 m/s
15 days
-2.3
0.05
Current Speed
1%
5%
10%
25%
50%
75%
90%
95%
99%
100%
10%
23%
68%
58%
24/4/07 00:00
704357mN
GMA:
0
Percentiles
to
177386mE
-2.980
80%
70%
residual 256
68%
60%
58%
50%
-0.4
threshold values
0.4
40%
mean
30%
Major axis :
Residual current :
210 (Deg-G)
0.022 m/s
at
0.119 m/s
256 (Deg-G)
23%
20%
10%
330≤340
300≤310
lat. residual
270≤280
240≤250
long. residual
210≤220
180≤190
150≤160
lat. amplitude
120≤130
long. amplitude
090≤100
lateral
0%
060≤070
longitudinal
0.40 m/s
Tidal amplitude
0.119 m/s
0.054 m/s
2.23
030≤040
Residual
0.015 m/s
0.016 m/s
0.95
10%
000≤010
Longitudinal (U) :
Lateral (V) :
Anisotropy (long'l/lat'l) :
-0.4
W~L
10m
9m
0.30 m/s
8m
0.20 m/s
7m
0.10 m/s
6m
0.00 m/s
5m
-0.10 m/s
4m
3m
-0.20 m/s
2m
25-Apr 0h
24-Apr 0h
23-Apr 0h
22-Apr 0h
21-Apr 0h
20-Apr 0h
19-Apr 0h
18-Apr 0h
17-Apr 0h
16-Apr 0h
15-Apr 0h
14-Apr 0h
13-Apr 0h
12-Apr 0h
11-Apr 0h
0m
10-Apr 0h
-0.40 m/s
09-Apr 0h
1m
08-Apr 0h
-0.30 m/s
BDnC_cbot_26.6m_bin25
Current meter ID :
declination:
Period of measurement :
-5.280
convergence:
9/4/07 00:00
0 hrs
0 mins
0.35
0.3
Percentile Analysis
thresholds
90%
0.4
major axis 210
mean
percentile analysis
15.66
14.23
12.64
0.25
0.2
0.15
100%
Max:
Mean:
Min:
Depth/
Pressure
(Deg-G)
0.1
0.013 m/s
0.022 m/s
0.029 m/s
0.046 m/s
0.072 m/s
0.109 m/s
0.153 m/s
0.186 m/s
0.238 m/s
0.289 m/s
0.030 m/s
0.045 m/s
0.095 m/s
0.083 m/s
15 days
-2.3
0.05
Current Speed
1%
5%
10%
25%
50%
75%
90%
95%
99%
100%
11%
24%
68%
60%
24/4/07 00:00
704357mN
GMA:
0
Percentiles
to
177386mE
-2.980
80%
70%
residual 246
68%
60%
60%
50%
-0.4
threshold values
0.4
40%
mean
30%
Major axis :
Residual current :
210 (Deg-G)
0.024 m/s
at
0.123 m/s
246 (Deg-G)
24%
20%
11%
10%
330≤340
300≤310
lat. residual
270≤280
240≤250
long. residual
210≤220
180≤190
150≤160
lat. amplitude
120≤130
long. amplitude
090≤100
lateral
0%
060≤070
longitudinal
0.40 m/s
Tidal amplitude
0.123 m/s
0.052 m/s
2.37
030≤040
Residual
0.019 m/s
0.014 m/s
1.37
000≤010
Longitudinal (U) :
Lateral (V) :
Anisotropy (long'l/lat'l) :
-0.4
W~L
18m
16m
0.30 m/s
14m
0.20 m/s
12m
0.10 m/s
10m
0.00 m/s
8m
6m
-0.10 m/s
4m
-0.20 m/s
2m
25-Apr 0h
24-Apr 0h
23-Apr 0h
22-Apr 0h
21-Apr 0h
20-Apr 0h
19-Apr 0h
18-Apr 0h
17-Apr 0h
16-Apr 0h
15-Apr 0h
14-Apr 0h
13-Apr 0h
12-Apr 0h
11-Apr 0h
10-Apr 0h
09-Apr 0h
0m
08-Apr 0h
-0.30 m/s
BDnC_nrbd_3.6m_bin02
Current meter ID :
declination:
Period of measurement :
-5.280
convergence:
9/4/07 00:00
0 hrs
0 mins
0.3
Percentile Analysis
thresholds
90%
0.4
major axis 210
mean
percentile analysis
38.61
37.18
35.59
0.25
0.2
0.15
100%
Max:
Mean:
Min:
Depth/
Pressure
(Deg-G)
0.1
0.012 m/s
0.026 m/s
0.032 m/s
0.049 m/s
0.076 m/s
0.109 m/s
0.146 m/s
0.168 m/s
0.215 m/s
0.245 m/s
0.030 m/s
0.045 m/s
0.095 m/s
0.084 m/s
15 days
-2.3
0.05
Current Speed
1%
5%
10%
25%
50%
75%
90%
95%
99%
100%
8%
21%
65%
55%
24/4/07 00:00
704357mN
GMA:
0
Percentiles
to
177386mE
-2.980
80%
residual 268
70%
65%
60%
55%
50%
-0.4
threshold values
0.4
40%
mean
30%
Major axis :
Residual current :
210 (Deg-G)
0.018 m/s
at
0.123 m/s
268 (Deg-G)
21%
20%
10%
0%
330≤340
300≤310
lat. residual
270≤280
240≤250
long. residual
210≤220
180≤190
150≤160
120≤130
lat. amplitude
090≤100
long. amplitude
060≤070
lateral
8%
030≤040
longitudinal
0.30 m/s
Tidal amplitude
0.123 m/s
0.049 m/s
2.50
000≤010
Longitudinal (U) :
Lateral (V) :
Anisotropy (long'l/lat'l) :
Residual
0.009 m/s
0.015 m/s
0.62
-0.4
W~L
45m
40m
0.20 m/s
35m
0.10 m/s
30m
25m
0.00 m/s
20m
-0.10 m/s
15m
10m
-0.20 m/s
5m
25-Apr 0h
24-Apr 0h
23-Apr 0h
22-Apr 0h
21-Apr 0h
20-Apr 0h
19-Apr 0h
18-Apr 0h
17-Apr 0h
16-Apr 0h
15-Apr 0h
14-Apr 0h
13-Apr 0h
12-Apr 0h
11-Apr 0h
10-Apr 0h
09-Apr 0h
0m
08-Apr 0h
-0.30 m/s
0.8
185
0.5
0.4
0.3
184
0.0
183
23-Apr-07
22-Apr-07
21-Apr-07
20-Apr-07
19-Apr-07
18-Apr-07
17-Apr-07
16-Apr-07
15-Apr-07
14-Apr-07
13-Apr-07
12-Apr-07
11-Apr-07
10-Apr-07
9-Apr-07
BDnC - ADP heading, pitch and roll time series
0.2
0.1
heading
pitch
roll
183
pitch, roll (deg)
0.6
184
heading (degM)
1.0
185
0.9
0.7
Met. station ID :
declination:
Period of measurement :
BDnC_wind
-5.280
9/4/07 00:00
convergence:
to
24/4/07 09:00
12
10
mean
20.0
80%
70%
10.0
percentile analysis
60%
56%
0.0
50%
50%
-20.0
-10.0
0.0
10.0
20.0
40%
threshold values
mean
-10.0
30%
20%
-20.0
10%
0%
330≤340
300≤310
270≤280
240≤250
210≤220
180≤190
150≤160
120≤130
090≤100
060≤070
3.4 m/s
1.8 m/s
1.0 m/s
thresholds
030≤040
24 hrs
Max:
Mean:
Min:
Percentile Analysis
000≤010
Rolling Average period:
90%
8
0.1 m/s
0.3 m/s
0.5 m/s
0.9 m/s
1.8 m/s
2.5 m/s
3.0 m/s
3.5 m/s
4.1 m/s
4.3 m/s
2.0 m/s
5.0 m/s
10.0 m/s
1.8 m/s
0 mins
6
1%
5%
10%
25%
50%
75%
90%
95%
99%
100%
56%
#N/A
#N/A
50%
9 hrs
4
Wind Speed
100%
704357mN
-2.3
2
Percentiles
15 days
177386mE
GMA:
0
heading reference: (Deg-G)
-2.980
360
5
330
5
300
4
270
4
240
210
3
180
3
150
2
120
2
090
1
060
1
030
000
8/4 0h
10/4 0h
12/4 0h
14/4 0h
16/4 0h
18/4 0h
20/4 0h
22/4 0h
24/4 0h
0
26/4 0h