A Flooded Landscape Revealed

3D Hydrodynamic Model Developed for Sustainable Water Abstraction

During the last week of a hydrographic survey of Lough Derg, Ireland’s third largest lake, the remnants of a preserved flooded landscape were unveiled beneath the surface with each passing swath. In early 2015, Geomara was commissioned by the utility company, Irish Water, to undertake a bathymetry and side-scan sonar survey of Lough Derg as part of the planning and design process for the Water Supply Project, Eastern and Midlands Region. This project aims to find a new water source to supply the future needs of the Midlands and Greater Dublin Area. Over the course of a typically wet and... (read more)

2016-04-04 10:00:41

Data Integration for Coastal Surveying

Combining Laser Scanner and Bathymetric Sensor

When surveying the coastline, the integration of bathymetric (below sea level) and laser scanning (above sea level) data causes problems due to the different imaging properties. However, by ensuring that the different data sets have been accurately georeferenced and oriented, a complete and accurate model of the terrain above and below sea level can be obtained. This technique was employed to survey the area of Portovenere in Italy, including the San Pietro church located on a steeply sloping rocky promontory, with positional accuracies in the order of 5cm.<P> View Larger Map One of the biggest issues incoastline survey is the... (read more)

2009-06-04 12:00:00

USGS Tethered ACP Platforms

New design means more safety and accuracy

The US Geological Survey has developed an innovative tethered platform that supports an Acoustic Current Profiler (ACP) in making stream-flow measurements (use of the term ACP in this article refers to a class of instruments and not a specific brand name or model). The tethered platform reduces the hazards involved in conventional methods of stream-flow measurement. The use of the platform reduces or eliminates time spent by personnel in streams and boats or on bridges and cable-way and stream-flow measurement accuracy is increased. One vital mission of the US Geological Survey (USGS) is to provide flow data for streams across... (read more)

2008-01-01 01:00:00

Submarine Volcanoes and Autonomous Survey Vehicles

Fringed by deep trenches, Japan is a country composed of seismic and volcanic active island arcs, where the huge Pacific Plate and the smaller Philippine Sea Plate converge to the Eurasian Plate. Integration of tectonic and volcanic activity since the geological Tertiary period formed beautiful mountainous landscapes and scattered small plains with rich soil. At sea around Japan, two volcanic ridges are extending to south and southwest from the mainland Japan. It means Japanese waters are not free from volcanic hazards. In the morning of 17 September 1952, the Chief Hydrographer of Japan received a telegram from a fishing boat... (read more)

2008-01-01 01:00:00

Slocum Gliders Make Historic Voyages

Autonomous vehicles from the company founded by AUV pioneer Doug Webb have recently made a historic 2600km voyage from New Jersey to Halifax and successfully drawn power from ocean thermal gradients for 3000km worth of data collection between St Thomas and St Croix.<P> Ocean engineers’ dreams docome true, as demonstrated by Doug Webb of Teledyne Webb Research, Falmouth, Massachusetts, USA. When he left the Woods Hole Oceanographic Institution in 1982 after 20 years there, it was to form his own company Webb Research Corporation, recently acquired by Teledyne, to develop and manufacture floats and sound sources. However, he was dreaming... (read more)

2008-08-27 12:00:00

USGS Tethered ACP Platforms

New design means more safety and accuracy

The US Geological Survey has developed an innovative tethered platform that supports an Acoustic Current Profiler (ACP) in making stream-flow measurements (use of the term ACP in this article refers to a class of instruments and not a specific brand name or model). The tethered platform reduces the hazards involved in conventional methods of stream-flow measurement. The use of the platform reduces or eliminates time spent by personnel in streams and boats or on bridges and cable-way and stream-flow measurement accuracy is increased. One vital mission of the US Geological Survey (USGS) is to provide flow data for streams across... (read more)

2008-01-01 01:00:00

EIVA

Marine Software and Integrated Systems Solutions

EIVA a/s, based in Aarhus, Denmark, is an independent software and systems company in design and manufacturing software and integrated, customised systems solutions for marine surveying. Founded in 1978, EIVA initially provided equipment, sensors and services for the offshore oil & gas industry. In 1982 the company began development of the NaviPac integrated navigation software. Since then it has undergone continual growth to become today’s recognised high-technology company with a main focus on software and integrated systems solutions for use in hydrographic surveying, seafloor mapping, offshore construction and inspection works, geophysical surveying, oceanographic research, etc. At the beginning of 2003... (read more)

2008-01-01 01:00:00

Improving the Accuracy of ADCP Discharge Measurements

Automating Edge Discharge Calculation in ADCP Software

There is a key new feature in the discharge measurement software ViSea DAS that allows the user to add a bottom profile. By doing so, side extrapolation from the start and end points of the survey track to the shore is calculated automatically using dGPS positioning. This removes the error inherent in estimating the track to shore distance for each individual track, which is the current method used in comparable software packages. This paper describes research that validates this new approach. Discharge measurements are important for the characterisation of rivers and are the basis of many models. There are many... (read more)

2014-05-19 02:19:44

Crowdsourcing for Hydrographic Data

A Tool for Updating Nautical Charts

Approximately 50% of the sounding data shown on US NOAA nautical charts is pre-1940, collected by antiquated lead-line soundings and wire drags. Even the 500,000 square nautical miles of the most navigationally significant EEZ waters would require 167 years to survey. Crowdsourced data can significantly augment authoritative geodata bases and provide answers to critical mapping deficiencies. The challenge in the marine geospatial sector is to ensure the reliability of crowdsourced data by managing and structuring the process to ensure that it can be confidently relied upon as useable and accurate. SURVICE Engineering and CARIS have developed the ARGUS system as... (read more)

2012-11-22 02:43:16

Solving Wakulla Springs Underwater Mysteries

Using GPS to map FloridaÕs underground caverns

Located in the Woodville Karst Plain stretching south from Tallahassee to the Gulf of Mexico, Florida’s Wakulla Springs is one of the largest and deepest freshwater springs in the world. It is also a gateway into one of the longest underwater cave system in the United States, a system that remained largely unexplored until recently. Soon, however, thanks to one of the world’s most extreme scientific and exploration-related diving projects ever undertaken, visitors to Wakulla Springs State Park will be able to take a virtual tour through the Spring’s huge underwater labyrinth. Using such cutting-edge technology as a 3D Digital... (read more)

2008-01-01 01:00:00