NSN work experience has covered every aspect of surface and ground water development permitting and impact analysis.
NSN incorporates state-of-the-art oceanographic technology in order to provide the most comprehensive analysis of coastal environments to our clients. Some of these instruments include a 4-beam Acoustic Doppler Current Profiler (ADCP), used to obtain detailed continuous data describing current speed and direction, water surface elevation, and wave patterns in order to understand flushing processes in near-shore environments. We also implement continuously-monitoring dissolved oxygen meters, manufactured by YSI, Inc. as an integral part of understanding water quality conditions in a variety of locales. Hand-held instruments and bathymetric data are used in conjunction with these devices to both describe and predict hydrologic and chemical processes at specific project sites.
- High performance water current profiler
- Generates data for wave direction, height and period
- Records current velocity (cm/s)
- Provides information on suspended sediment concentrations
- Records water surface elevation
YSI Meter:
This instrument can be placed at various stations throughout a project site and left for days at a time, continuously recording dissolved oxygen, salinity, temperature, pH, conductivity and barometric pressure. This type of high resolution, time-series data is useful in understanding how parameters related to water quality are changing over a range of time scales.
Acoustic Doppler Current Profiler
YSI Meter
This aerial photograph shows the marina in its entirety. The red stations were set out in a grid surrounding the area of concern for construction. Hand-held measurements of a variety of water quality parameters were taken at each station at every foot through the water column. The yellow stations indicate the areas where the ADCP and/or the YSI dissolved oxygen meter was left to continuously record hydrologic and chemical data for periods of two to four days.
This film clip shows how water velocity changes with tidal forcing over a 74-hour period. Warm colors indicate low velocities and cool colors indicate high velocities. The vectors indicate the direction of flow in a given time step. These types of film clips are useful in providing a visual understanding of circulation processes in a given environment.
*The movie may take a few minutes to load.
This graphic depicts current velocity vectors during a time of maximum discharge of water from the marina, along with a colored contour of current speed in meters per second. Warmer colors indicate slower velocities, and cooler colors indicate increased levels of water movement. The model software allows us to pick specific points within the marina waters and generate time-series profiles of velocity throughout the model simulation time.
Colored contours represent velocities in meters/second.
Land represented by brown grid squares.
*Click on graphic to enlarge
Model – Bathymetry Graphic
In addition to in-situ measurements and direct interpretation, NSN provided a state-of-the-art computer model describing the hydrologic dynamics in this particular marina basin. Real-time bathymetric data was obtained and combined with tidal information, physical characteristics of the water, and time specifications in order to simulate circulation throughout the entire marina. This map provides a bathymetric profile of the marina, and indicates the areas where discharge levels were calculated to understand flushing processes.
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Time Series Plot
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DO at 12 feet
NSN used computer software to generate contour maps of the various data sets obtained with the hand-held instruments throughout all depths at all stations. This map shows the levels of dissolved oxygen in the area of concern at a depth of 12 feet below the surface.
*Click on graphic to enlarge
DO at Surface
This map shows the levels of dissolved oxygen recorded throughout the surface waters in the area of concern. The contouring of all water depths allows for a straightforward, graphical presentation of the variability in water chemistry throughout the marina, and is useful in determining the exact location of potential circulatory issues.
*Click on graphic to enlarge
DO – YSI Time Series plot
This plot shows the dissolved oxygen data obtained using the YSI meters at three depths in the water column at one of the stations in the marina. This data can be combined with the interpretations made from the hand-held instrument data to provide a more comprehensive understanding of water column chemistry over time.
*Click on graphic to enlarge
This plot shows the water current data collected from the ADCP at one of the stations in the marina, converted to discharge and inflow using tidal information. This data is critical in understanding the degree of flushing that is occurring in the marina. Additionally, this type of data can be used to help calibrate a hydrodynamic computer model.
*Click on graphic to enlarge