Report of Survey El Bluff / Bluefields, Nicaragua 09NU02 fleet survey team

Report of Survey El Bluff / Bluefields, Nicaragua 09NU02

FLEET SURVEY TEAM
REPORT OF SURVEY

General Area	Nicaragua – East Coast
Name of Survey	El Bluff and Bluefields, Nicaragua
Archive #	09NU02
Unit Name	Fleet Survey Team
Hydrographer in Charge	Mr. Ian Fergusson
Survey Start Date	12 November 2008
Survey End Date	17 December 2008

UNCLASSIFIED

DISTRIBUTION STATEMENT D

DISTRIBUTION AUTHORIZED TO THE GOVERNMENT OF NICARAGUA, DOD AND U.S. DOD CONTRACTORS ONLY. FOREIGN GOVERNMENT INFORMATION: 18 OCTOBER 2008 THIS INFORMATION MAY NOT BE RELEASED TO A THIRD COUNTRY / PARTY WITHOUT PRIOR APPROVAL. ALL U.S. REQUESTS SHALL BE REFERRED TO: COMMANDING OFFICER, FLEET SURVEY TEAM / NAVAL OCEANOGRAPHIC OFFICE AND THE GOVERNMENT OF NICARAGUA.

FLEET SURVEY TEAM

STENNIS SPACE CENTER, MISSISSIPPI

REPORT OF SURVEY

ARCHIVE # 09NU02
Country: Nicaragua
Area: El Bluff and Bluefields – East Coast – Caribbean Sea
Dates of Survey: 14 November – 17 December 2008
Archive #: 09NU02
Charts:

NGA DNC: DNC 14 Caribbean Sea

H1409770 Bluefields

NGA Chart: 28082 Bluefields

28082 Plan El Bluff

Sailing Directions: NGA PUB Pub 148, Caribbean Sea, Vol II, 2008

Sector 5, Sub Sector 5.29 to 5.30
World Port Index: 9769 EL BLUFF

9770 BLUEFIELDS

NGA List of Lights: PUB 113 (Light #16500) El Bluefields Bluff

Horizontal Datum: World Geodetic System 1984 (WGS-84)
Projection: Transverse Mercator
Grid: Universal Transverse Mercator (UTM), Zone 17 N
Sounding Datum: Mean Lower Low Water (MLLW)
Vertical Datum: Mean Sea Level (MSL)
23 FEB 2009

MEMORANDUM

From: Mr. Ian Fergusson, Hydrographer in Charge, Plans Department Head

To: Commanding Officer, Fleet Survey Team

Via: Plans Department

Subj: INTERNATIONAL HYDROGRAPHIC ORGANIZATION SURVEY ORDER RECOMMENDATION FOR SURVEY 09NU02

1. Recommend that survey Archive Number 09NU02 as submitted be accepted as meeting International Hydrographic Organization Order 1a survey standards in accordance with IHO Special Publication 44, Fifth Edition (2008). All data as noted in the following report meets or exceeds the requirement for IHO Order 1a Survey.

.

MR. IAN FERGUSSON

Hydrographer in Charge Nicaragua

El Bluff and Bluefields – 09NU02

2. Recommend that survey Archive Number 09NU02 as submitted be accepted and distributed in accordance with Technical Specifications 09NU02.

LCDR M. SALAZAR

PLANS Department

Fleet Survey Team

3. Concur with recommendation and approve release of survey data in accordance with Technical Specification 09NU02.

CDR R. R. DELGADO

Commanding Officer

Fleet Survey Team

SURVEY TEAM

Name	Qualification	Dates	Position
Mr. Ian Fergusson	ACSM Certified	14 Nov to 17 Dec 08	Hydrographer in Charge
LT Travis Clem	Hydrographer, Cat A	1 Dec to 17 Dec 08	Hydrographer in Charge (U/I)
Mr. A. J. Pearson	Hydrographer	14 Nov to 17 Dec 08	Data Manager
AG3 Andrew Jackson	Technician/Coxswain	1 Dec to 18 Dec 08	Coxswain/ Survey Assistant
Mr. Jerry Worth	Electronic Technician	18 Nov to 17 Dec 08	Electronic Technician
AG2 Joshua Clark	Survey Technician	1 Dec to 18 Dec 08	Data Collection
AGAN Lydia Carr	Survey Technician	1 Dec to 18 Dec 08	Data Collection

STATISTICS

PRIMARY DATA COLLECTION	MILEAGE	REMARKS
SBES El Bluff - Harbor and Approach & Bluefields Channel	181.9 LNM	200 kHz 20m Line Spacing
SSS El Bluff – Harbor and Approach & Bluefields Channel	66.9 LNM	Klein 3000, 40m Line Spacing 50m Swath
TOTAL	181.9 LNM

DATA TYPE	GOOD	BAD	TOTAL	REMARKS
Bottom Samples	14	0	14
CTD Casts	10	9	19
Kinematic Shoreline (km)	4.37	0	4.37	Taken with the NAVCOM SF2040G receiver.
Weather Observations	17	0	17	Daily observations
Tidal Data Station	31 days	0	31 days	Station Compared to Admiralty Total Tides and Nicaraguan Tidal Report INTER.

DATA DELIVERED	NUMBER	SCALE	REMARKS
Final Smooth Sheets	2	1 : 7,500	The Government of Nicaragua, NGA, COMUSNAVSOUTH and NAVOCEANO

DAY COUNT

ACTION	NUMBER	REMARKS
Mobilization Days	2	Includes Craning Launch into Water from Barge, Equipment Set-up and Initial Area Outline.
Bathymetric Data Collection days	8	On Water days Collecting Bathymetry
Ancillary Data Collection days	1	Tide Gauge Installation and Removal, NAVCOM Static Test, Bottom Samples, ATONs, Shoreline Delineation
Days Lost to Boat Casualty	8	Broken SSS TPU, All TPU Operations Stopped
Days Lost to Weather	0
Decommissioning	2	Removal and Gear Pack Out
Days Lost Awaiting Cargo Transport	15	See Appendix N Daily Narrative and Timeline.
Total days Team on Site	18	See Appendix N Daily Narrative and Timeline

REPORT OF SURVEY CONTENTS

1. 
   General ………………………………………………………………………………... 10
   
   1. 
      Requirements.....................................................................................................10
      
   2. 
      Survey Area and Objectives …………………………………………………. 10
      
   3. 
      Elements Affecting Survey Operations ………………………………….…...10
      

2. 
   Geodetic Control…………………………………………………………………….....11
   
   1. 
      Datum ………………………………………………………………………...11
      
   2. 
      Geodetic Control, Existing and Established ……………………………….... 11
      
   3. 
      Shoreline Delineation………………………………………………………… 11
      

3. 
   Data Acquisition and Processing Systems …………………………………………. 11
   
   1. 
      Data Acquisition Systems …………………………………………………… 11
      
   2. 
      Data Processing Systems ……………………………………………………. 12
      

4. 
   Calibration and Vessel Configuration ………………............................................... 12
   
   1. 
      Horizontal Positioning Systems.................………………………………….. 12
      
   2. 
      Vessel System Calibration............................................................................... 12
      
   3. 
      Hydrographic Survey Platform Configuration ……………………………... 13
      
   4. 
      Side Scan Sonar Configuration…………………………………………….... 13
      
   5. 
      Sound Velocity Adjustments ……………………………………………….. 13
      

5. 
   Tides, Tide Gauges and Sounding Datum…………………………………………... 14
   
   1. 
      Establishment of Tidal Datum……………………………………………….. 14
      
   2. 
      Tide Gauge to Staff Comparison..................……………………………….... 14
      
   3. 
      Tidal Datum Comparison ……………………………………………………. 14
      
   4. 
      Tide Gauge Malfunctions ………………………………………………….... 15
      

6. 
   Sounding Development.........................………………………………………………. 15
   
   1. 
      Area 1b, Approach to El Bluff Channel…………………………………….... 15
      
   2. 
      Area 1a, El Bluff Harbor……………………………………………………... 15
      
   3. 
      Area 2a, Escondido River Channel.................................................................. 15
      
   4. 
      Target Investigations ........................................................................................15
      

6.5. Sounding Selection …………………………………………………………...15

7. 
   Crosscheck Analysis..................................……….…………………………………... 16
   
   1. 
      Area 1a and 1b ..................................…………………………………...….. 16
      
   2. 
      Area 2a.............................……………………………………………..…...... 16
      
   3. 
      Crosscheck Comparisons...................................................................................16
      

8. 
   Agreement with Existing Charts ……………………………………………………. 16
   

8.1. Existing Charts.………………………………………………………………. 16

8.2. Approach................…………………………………………………………... 16

8.3 El Bluff Pier......……………………………………………………………... 16

4. 
   Agreement with Prior Surveys ......................................................................... 16
   

8. 
   Charted and Uncharted Wrecks and Obstructions ……………………………….. 17
   

1. 
   Charted Wrecks and Obstructions ……………………………………….........17
   
2. 
   Uncharted Wrecks and Obstructions ………………………………………... 18
   

9. 
   Charted and Uncharted Lights, NAVAIDs, Buoys and Piers ..…………………... 18
   

10.1. Charted/Uncharted NAVAIDs

10.2. Survey of Lights...................................……………………………………… 18

10.3. Position of Buoys ……………………………….……………………………18

9. 
   Sailing Directions and Nomenclature...............…………………………………..... 19
   

11.1. General ................ ……………………………………………………...…… 19

1. 
   Landmarks ............ ………………………………………………………...... 19
   
2. 
   Anchorage and Moorings….............................................................................19
   

11. 
    Seabed Topography and Bottom Samples ..……………………………….…...…. 19
    
    1. 
       Seabed Topography ….………………………………………………..……. 19
       
    2. 
       Seabed Samples…...................……………………………………………… 19
       

11. 
    Coastline, Topography, Conspicuous Objects .….…...…………………………… 19
    
    1. 
       Coastline Positioning ...........………………………………………………. 19
       
    2. 
       Beach Morphology…...…………………………………………………….. 19
       

11. 
    Ancillary Observations .……………………………………………………………. 19
    
    1. 
       Meteorological Data…..…………………....………………………………. 19
       

11. 
    Summary………………………………………………………………………........... 20
    
    1. 
       Summary………..…………………………………………………................20
       
    2. 
       Hydrographers Recommendation…................................................................20
       

APPENDICES:
A Survey Area Graphic and Technical Specifications

B Daily Weather Log

C Seabed Features and Contacts Report

D NAVAID Lights and Buoys List, Photographs

E Bottom Sample Drop Locations, Log (M Sheet) and Analysis

F Tide Report, Level Lines, Tidal Analysis and Tidal Block

G Geodetic Station Calibration Results

H & I Data Collection and Processing Equipment and Software Lists

J Geodetic Stations and OPUS Solutions

K CTD Log, Profiles and Analysis

L Crosscheck Analysis

M Sailing Directions and Port Index

N Daily Timeline of Events

1. 
   General
   

1.1. Requirements: The primary objective of this survey operation was to collect

environmental and navigational data in the port and approaches to El Bluff,

Nicaragua in accordance with Oceanographic, Hydrographic and Bathymetric

2008 requirements and Technical Specifications 09NU02 Appendix A. The

products generated from this survey will support the safe navigation of ships in

this area through the updating of nautical charts.

1. 
   NGA 2006 Assessment: El Bluff NU (28110) U.S. Chart 28082 is a harbor scale chart of Bluefields. It was made from a U.S. Navy Survey (Appendix A) of 1966 and UKHO Charts from 1900. The Navy surveys are 40 years old and the British data is ancient, recommend resurvey.
   

2. 
   The survey further supports the Theater Security Cooperation (TSC) objectives of USSOUTHCOM. The extents of survey operations, area graphics and Technical Specifications are given in Appendix A.
   

2. 
   Survey Area and Objectives: The area surveyed is within the territorial waters of
   

Nicaragua. The survey area was El Bluff pier, Approach to the 10m contour line,

and Channel from El Bluff to the mouth of the Escondido River. See Appendix A

for area graphics and area coordinates. All areas were surveyed to International

Hydrographic Organization Order 1a Standards. Real-time water level data were

collected (See Appendix F) and tidal corrections were applied to all soundings.

Current charts indicate four known wrecks or hazards. Three wrecks were

identified during survey operations, See Appendix C. Navigation aids in the

survey area were verified and the results are contained in Appendix D.

3. 
   Elements Affecting Survey Operations:
   

1. 
   Weather: El Bluff / Bluefields, Nicaragua has a tropical climate affected
   

by the Caribbean Sea as well as the Mountains to the east and north. Low

pressure systems passing to the north yielded North North East winds and

seas for most of the survey. The strength of these winds varied from light

and variable to gusts of 13 knots at their peak. Weather was not a big

impact on collection with the exception of large (1.0m to 1.7m) offshore

swells in the Approach area. In periods of heavy weather the team was

able to work inside of Bluefields Bay. See Appendix B for daily weather

observations.

2. 
   Local Elements: Large derelict shrimp boat fleet (approximately 30 boats some floating and some sinking) prevented survey operations close to the Punta Pescado pier. Shipping traffic to and from El Bluff pier and barge traffic up the Escondido River channel did not affect data collection.
   
   
   
   

2. 
   Geodetic Control
   

1. 
   Datum:
   

1. 
   Horizontal Datum: World Geodetic System 1984 (WGS 84)
   

2.1.2. Projection Grid: Universal Transverse Mercator, North Zone 17

(78° W – 84° W)

3. 
   Vertical Datum: Mean Sea Level (MSL)
   

3. 
   Sounding Datum: Mean Lower Low Water (MLLW)
   

2. 
   Geodetic Control, Existing and Established: The survey team used the NAVCOM SF2040G system for all aspects of the survey. One geodetic control point from the Inter American Geodetic Survey (1949) was located near the Port Captain Station in El Bluff, however, repeated attempts to position the marker failed due to large buildings and trees blocking the signal. Additionally, 3 Control points (BM A, BM B and BM C) were established by the team and tied into ITRF 2000 using NOAA OPUS.
   

1. 
   Existing Control Points: IAGS 1949 point located next to the Port Captains
   

Building was recovered. However, several attempts (2) to re-establish control

at the point failed, possibly, due to masking by nearby structures (did not use

GPS in 1949). No other existing control Marks were found.

1. 
   New Control Points: The team established Benchmarks closer to the pier along the pier wall in El Bluff. These Bench Marks labeled BMA, BMB and BMC are bolts epoxy glued into the concrete wall. 6 hours of RINEX data was collected on each point and the data submitted to NOAA’s OPUS to acquire final data solutions listed in Appendix J. In addition the north east corner of the El Bluff light concrete pad was positioned with 6 hours of observation final data solution listed in Appendix J.
   
   
2. 
   Shoreline Delineation: GPS points along the El Bluff shoreline and pier were captured in ASCII format using the NAVCOM SF2040G GPS Receiver and the Rugged Reader and were downloaded into CARIS GIS software for display on the smooth sheet. Approximately 4.37 kilometer of shoreline was delineated with the NAVCOM SF2040G Receiver and input to CARIS GIS for shoreline representation.
   
   
   

3. 
   Data Acquisition and Processing Systems
   

1. 
   Data Acquisition Systems: The ODOM Echotrac CV200 and TSS DMS-25
   

Heave/Pitch Compensator experienced no significant problems in collection.

However, the heave/pitch compensator showed a -0.45 second delay. Data

collection software system used for singlebeam was HYPACK 6.2b. Heave error

induced due to large period swells was mitigated by adjusting survey speed and

adjustment of main scheme orientation. A list of all systems used in Data Collection

can be seen in Appendix H.

3.2. Data Processing Systems: Data processing was performed using CARIS HIPS and

SIPS 6.1. The data was ingested in CARIS HIPS for initial cleaning, filtering and

application of tides, sound velocity, total propagated error and true heave as well as

verification of navigation and attitude. The final edited data was returned to HIPS

and then exported to CARIS GIS for smooth sheet production. No significant

problems were experienced with the systems used for data processing. A list of all

software used in Data Processing can be seen in Appendix I.

3. 
   Calibration and Vessel Configuration
   

1. 
   Horizontal Positioning Systems: The NAVCOM SF2050M GPS System provided
   

all horizontal positioning for the survey vessel. A 24 hour static accuracy test was

conducted on 28 OCT 08, referenced to BM1 in Puerto Cabezas. A full test failed

due to signal disruption caused by passing traffic, however, 11 hours of continuous

data was preserved and processed in SA Watch, see Horizontal Calibration Check

(Appendix G). The system was compared to the OPUS derived position for BM1

(See Appendix J) with a 0.4m error at 99% confidence level (See Appendix G). The

SF2050M was also used to position buoys. The NAVCOM SF2040G Rover System

was used to position shoreline and land based NAVAIDs.

2. 
   Vessel System Calibration:
   

1. 
   GPS System: A standard latency test on the Navigation system was conducted using HYPACK 6.2b with a latency of 0.30 sec determined from averaging 8 runs across a known target. This value (0.30 sec.) was entered into the CARIS Vessel Configuration File (.hvf) for this vessel (Appendix G).
   

2. 
   Echosounder: Singlebeam echosounder was confirmed daily against lead line. An average value of 0.6m below the waterline was applied throughout the project as variances were within 0.02m of this value. The CARIS waterline height was then determined by subtracting the static transducer draft measurements from the Z offset between the transducer and the TSS DMS-25 (-1.984m) and was subsequently entered in the CARIS vessel configuration file. Results of the static transducer draft measurements and CARIS waterline calculations can be seen in Appendix G.
   

3. 
   TSS DMS-25: The TSS DMS-25 Heave, Pitch Compensator was used as the vessel reference point (0, 0, 0 point) and all measurements were taken from it. Using CARIS Calibration tool and three passes over a known object, it was determined that the DMS-25 had a latency error of -0.45 seconds. This value was placed in the vessel configuration file as seen in Appendix G.
   

2. 
   Hydrographic Survey Platform Configuration: The survey was conducted on the FST 9m RHIB “RIVER RAT”. Sensor offsets and position can be seen in Appendix G. Those results were entered in the vessel configuration file and are also presented in Appendix G.
   

Device	Horizontal Lever Arm	Fore / Aft Port / Starboard	Vertical Lever Arm	Above Water Line / Below Water Line	Notes
NAVCOM Antenna	0.100m	Aft (-)	1.984m	Above (+)
	0.200m	Port (-)
Heave / Pitch Compensator	0.000m	Forward (+)	0.000m	Above (+)
	0.000m	Port (-)
Transducer	0.120m	Stbd (+)	1.184m	Below Ref
	-2.344m	Aft (-)	0.600m	Below Water Line	DRAFT

2. 
   Side Scan Sonar Configuration: Klein 3000 Side Scan Sonar system was used throughout the project, with cable out being measured using the 3PS digital block.
   

The 3PS digital block experienced problems dealing with the slacking and taut due

to pitch. This was compensated for by manual input of line out for SSS, using the

position of the 3PS block as reference point.

Device	Horizontal	Fore / Aft Port / Starboard	Vertical	Above Water Line / Below Water Line	Notes
3PS Digital block	-4.4m	Aft (-)	1.50m	Above (+)
	0.0m	Centerline

2. 
   Sound Velocity Adjustments: SV profiles were obtained by a Seabird SBE-19 CTD.
   

Casts were conducted twice daily (exceptions being JD 339, 347, 348, 349, 350 and

351). Details of all SV data collection can be found in Appendix K. Sound Velocity

adjustments were entered into CARIS as SVP files, copy is in Appendix K. Table

below represents the Average – Maximum – Minimum – Median and Standard

Deviation of the CTD datasets (See Appendix K for details). Fresh water due to

inflow of the Escondido River and surface layer due to heavy thunderstorm

precipitation is the bulk of the changes noted. Also, due to the shallow water in the

River Channel most of the observations were 4m or less. 8 m or more observations

were noted in the Outer 1b area and are due to good mixing of the water mass in the

open ocean environment.

4. 
   Tides, Tide Gauges and Sounding Datum
   

1. 
   Establishment of Tidal Datum: An In-Situ vented tide gauge was installed onto a
   

three meter tide staff hard mounted on to the pier piling (N 11° 59’ 53.4” / W 083°

41’ 28.0”). Continuous data was collected for a duration of 34 days. The Chart

Datum is Mean Lower Low Water (MLLW) and was determined from NAVOTAS

least squares solution. Details of MLLW determination can be seen in Appendix F.

All manipulations and downloads of data from the In-Situ tide gauge were done

through Win-Situ 5.0. Tide Gauge Zero was tied to the WGS 84 Ellipsoid by a

direct reading to BM B using a laser level. BM B was tied to the WGS 84 Ellipsoid

by a 6 hour static observation on BM B using a NAVCOM SF2040G. All soundings

are reduced to sounding datum (MLLW). See Appendix F for additional

information.

2. 
   Tide Gauge to Staff Comparison: No Tide Staff to Tide Gauge readout comparison was performed.
   

2. 
   Tidal Datum Comparison: NAVOTAS Tide Datum results were compared to Admiralty Total Tides for Puerto Cabezas with the following results.
   

Diurnal	Admiralty Value	Mixed Tide Prevailing Semi-Diurnal	NAVOTAS
Mean Higher High Water	0.3m	Mean High Water Springs	0.40m
Mean Lower High Water	0.1m	Mean High Water Neaps	0.30m
Mean Sea Level	0.1m	Mean Sea Level	0.21m
Mean Higher Low Water	0.1m	Mean Low Water Neaps	0.10m
Mean Lower Low Water	0.0m	Mean Low Water Springs	0.00m

2. 
   Tide Gauge Malfunctions: None.
   

4. 
   Sounding Development
   

2. 
   Area 1b, Approach to El Bluff Channel: The development line plan was established to run down the estimated center of the Marked (buoys) channel and out 200m either side of the channel into the Area 1A channel. The main survey development line plan was oriented 133º/313º with a singlebeam line spacing of 20 meters, SSS line spacing of 40 meters and surveyed at approximately 4.0 knots. HYPACK 6.2b was used to record all data from the ODOM CV200 echosounder. A TSS DMS-25 Heave/Pitch Compensator sent data at 1 Hz to HYPACK. GPS data from the NAVCOM SF2050M receiver was sent to HYPACK at 1 Hz.
   
   
   
3. 
   Area 1a, El Bluff Harbor: The development line plan was established to run approximately parallel to the main channel into El Bluff and from the Escondido channel to the Approach Channel to El Bluff. The main survey development line plan was oriented 16º/196º with a singlebeam line spacing of 20 meters, SSS line spacing of 40 meters and a survey speed of approximately 4.0 knots. HYPACK 6.2b was used to record all data from the ODOM CV200 echosounder. A TSS DMS-25 Heave/Pitch Compensator sent data at 1 Hz to HYPACK. GPS data from the NAVCOM SF2050M receiver was sent to HYPACK at 1 Hz.
   

2. 
   Area 2a, Escondido River Channel: The development line was a 4 segment line adapted to run parallel to the center of the Marked (buoys) channel from the El Bluff Harbor basin to the Mouth of the Escondido River. The main survey development line was run with a singlebeam line spacing of 20 meters, SSS line spacing of 40 meters and surveyed at approximately 4.0 knots. HYPACK 6.2b was used to record all data from the ODOM CV200 echosounder. A TSS DMS-25 Heave/Pitch Compensator sent data at 1 Hz to HYPACK. GPS data from the NAVCOM SF2050M receiver was sent to HYPACK at 1 Hz.
   

6.4. Target Investigations: There were no direct target investigations performed during

this survey. One wreck was found using Side Scan Sonar; Wreck Location: 11° 59’

40.2384” N / 083° 41’ 51.0032” W. Wreck is believed to be Wreck charted (DNC

H1409770) at Location: 11° 59’ 44.1677” N / 083° 41’ 50.5117” W which was not

found as charted. Additionally, stranded wrecks above water were sited at

approximately 11° 59’ 40.1100” N / 083° 41’ 41.3947” W and 11° 59’ 35.5052” N

/ 083° 41’ 41.2555” W. Survey team was unable to safely verify exact positions

which were not in a navigable area, (See Appendix C).

5. 
   Sounding Selection: CARIS HIPS, Version 6.1 was used to determine least depth
   

soundings. CARIS HIPS applied shoal-biased sounding selection with a 0.5 meter

bin. Further suppression of soundings was conducted within CARIS GIS, Version

4.4a. All suppressions of soundings retained the shoalest soundings.

6. 
   Crosscheck Analysis
   

7.1. Area 1a and 1b: The crosscheck survey line plan was oriented 90° to development

lines, spaced at 400 meters and surveyed at approximately 4.0 knots. Data recording

was identical to development line recording in 6.1 above.

7.2. Area 2a: The crosscheck survey line plan was oriented 90° to development lines

and crosschecks were placed at beginning, middle and end of each segment to

ensure coverage.
7.3. Crosscheck Comparisons: Crosscheck line soundings were compared to

development line soundings visually using CARIS HIPS 6.1 subset editor and

mathematically using the quality control verification tool to ensure IHO standard

required accuracies. The QC tool showed that 95.4% of the crosschecks met IHO

Order 1a standards. All crosscheck comparison details and results can be seen in

Appendix L.

Count Max (+) Min (-) Mean Std Dev Special Order Order 1a

18959 1.748 1.448 0.044 0.225 79.7 % 95.4 %

6. 
   Agreement with Existing Charts
   

8.1. Existing Charts: The charts include NGA DNC 14 Caribbean Sea, DNC H1409770

Bluefields and NGA Chart 28082 Bluefields with PLAN 28082A El Bluff.
8.2. Approach: The approach area was comparable to the NGA Chart 28082 and the

NGA DNC H1409770 with the following exceptions: surveyed positions and

disposition of wrecks differ between the paper and digital charts (See Appendix D).

In addition there is a large bar across the mouth of the channel approach created by

currents from Seaward and River approximately along the line 11° 59’ 00” N where

the bottom goes to a Shoalest depth of 4.2m. Indications of Dredging were observed

at the entry to the Pier, however, any dredging across the bar has been filled in.
8.3. EL Bluff Pier: El Bluff pier has been dredged to a depth of 6m, however, dredged

area is showing signs of filling in with sediment transported from the Escondido

River.

4. 
   Agreement with Prior Surveys: No prior survey data was available, therefore, no
   

comparisons could be made by the survey team.

8. 
   Charted and Uncharted Wrecks and Obstructions
   

1. 
   Charted Wrecks and Obstructions:
   

1. 
   Chart: NGA Chart 28082 Bluefields and El Bluff Approach was compared to data collected in the survey area.
   

Charted Wrecks Shown on NGA Chart 28082
Symbol	Notes on Chart	Latitude	Longitude	Comments	Recommendation
	"Mast"	11-59-35.30 N	083-41-46.70 W	Not Found with 200% Side Scan Sonar Search	Remove from Chart
		11-59-44.30 N	083-41-51.00 W	Not Observed	Remove from Chart
		11-59-57.85 N	083-41-27.03 W	Observed, PA	Retain on Chart

2. 
   NGA DNC: DNC Tile H10409770 was compared to data collected in the survey area:
   
   

Charted Wrecks Shown on NGA DNC 14, Tile H1409770
Symbol	Notes	Latitude	Longitude	Comments	Recommendation
		11-59-35.30 N	083-41-46.70 W	Not Found with 200% Side Scan Sonar Search	Remove from DNC
		11-59-44.30 N	083-41-51.00 W	Not Found with 200% Side Scan Sonar Search	Remove from DNC
		11-59-57.85 N	083-41-27.03 W	Observed as Wreck Awash PA	Retain on DNC, Change Symbol

2. 
   Uncharted Wrecks and Obstructions: The following wrecks and obstructions were
   

observed by side scan sonar or directly sited. (See Appendix C).

Uncharted Wrecks Observed in Survey Area
Contact #	Notes	Latitude	Longitude	Comments	Recommendation
0001 and 0001a	Sunken Wreck, Wreck is outside of Channel	11-59-40.24 N	083-41-51.00 W	Least Depth 2.3m in 3.4m of Water	Add to Chart, Wk, Least Depth of 2.3m
0002	Debris	11-59-52.69 N	083-41-37.90 W	Least depth of 6.0m in 8.6 m of Water	Add to Chart, Obstn, Least Depth of 6.0m
Visually Observed Stranded Wreck	Approximate Position, could not pull along side of wreck for safety reasons	11-59-36.16 N	083-41-41.76 W	Wreck Awash, Position Approximate	Add to Chart, Wreck Awash, PA

9. 
   Charted and Uncharted Lights, NAVAIDs, Buoys and Piers
   

10.1. Charted/Uncharted NAVAIDs: Positions of existing NAVAIDs within the survey

area were observed and logged, See Appendix D. None of the NAVAID buoys

were depicted on the either NGA Chart 28082 or DNC H1409770.

2. 
   Survey of Lights: El Bluefield Bluff Summit Light is correctly positioned on
   

Chart and DNC and was verified by 6 Hour Geodetic Observation. Recommend

changing name to El Bluff Light to avoid confusion.

1. 
   Three Towers depicted on DNC and Chart at location:
   

1. 
   11° 59’ 23.2361” N / 083° 41’ 34.7743” W
   

2. 
   11° 59’ 29.5458” N / 083° 41’ 27.1449” W
   

3. 
   11° 59’ 44.5916” N / 083° 41’ 28.1993” W
   

The above three Towers do Not exist and should be removed from Charts and

DNC. See Appendix D. The Tramway at El Bluff, also, no longer exists.
10.3. Position of Buoys: No buoys were previously charted, however, twenty two buoys

were observed within the survey area. See Appendix D for position and photos.

10. 
    Sailing Directions and Nomenclature
    

11.1. General: NGA PUB 148, Caribbean Sea, Vol. II, 2008, has Sailing Direction

coverage of the approach to El Bluff, Nicaragua. Section 5.29 to 5.30, See

Appendix D for changes to the current Sailing Directions.
11.2. Landmarks: From Seaward the approach to El Bluff is marked by the El Bluff

Light that is prominent on the hill overlooking El Bluff Harbor. Cell Towers, the

Airport and the town of Bluefields would also be visible from Seaward. See

Appendix D.

3. 
   Anchorage and Moorings: There are no Seaward Anchorages or Mooring buoys.
   

The only anchorage area is inside the channel entrance opposite the El Bluff

pier. Descriptions and photographs are presented in Appendix D.

11. 
    Seabed Topography and Bottom Samples
    

1. 
   Seabed Topography: The majority of the survey area is a flat sand/mud bottom
   

with some rock outcroppings. Clay, Sand and Vegetation was found at the channel

opening due to Escondido River outflow.

12.2. Seabed Samples: Bottom samples were collected using a Ponar hinged bottom

grab deployed and retrieved by hand. A total of 14 samples were collected

throughout the survey area. Location and summary of bottom sediment collection

can be seen in Appendix E. Seabed samples were turned over to Naval

Oceanographic Geology Lab for analysis and categorization, results of that

Analysis can be seen in Appendix E.

11. 
    Coastline, Topography, Conspicuous Objects
    

1. 
   Coastline Positioning: GPS points were collected along the shoreline with the
   

NAVCOM SF2040G Receiver and used to verify DNC and chart differences. The

shoreline was ingested into HYPACK 6.2b and compared to DNC. Variations

between the two shorelines were less than 14 meters.
13.2. Beach Morphology: Beach height, including observations of significant foreshore

erosion and accretion, was not observed by the survey team.

11. 
    Ancillary Observations
    

1. 
   Meteorological Data: See Appendix B.
   

14. 
    Summary
    

1. 
   Summary: Survey 09NU02 was conducted to fulfill the USNAVSOUTH
   

hydrographic requirement and support Theater Security Cooperation objectives.

The products generated from this survey will support the safe navigation of ships

into and out of the harbor of El Bluff, Nicaragua. The data collected by the team

meets IHO Order 1a standards for horizontal and vertical accuracies defined by the

IHO S-44, Edition 5 publication.

2. 
   Hydrographer’s Recommendation: No further singlebeam Echosounder and side
   

scan sonar survey of the Port of El Bluff and Approach is required. The Channel

from the Mouth of the Escondido River to Bluefields was not surveyed and is

considered unusable by any vessel with draft greater than 1 meter, due to numerous

rock outcrops. While there was evidence of dredging the El Bluff Harbor mouth is

blocked by a large bar, making passage to El Bluff unsuitable for vessels with draft

in excess of 4m.