Evaluating the Capabilities of the Second Generation PICS Settling Column
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Grace M. Cartwright, S. Jarrell Smith , Carl T. Friedrichs, and Kelsey A. Fall PowerPoint PPT Presentation


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Evaluating the Capabilities of the Second Generation PICS Settling Column Floc Camera in a Muddy Tidal Estuary, York River, Virginia, USA. Grace M. Cartwright, S. Jarrell Smith , Carl T. Friedrichs, and Kelsey A. Fall. US Army Corps of Engineers

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Grace M. Cartwright, S. Jarrell Smith , Carl T. Friedrichs, and Kelsey A. Fall

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Grace m cartwright s jarrell smith carl t friedrichs and kelsey a fall

Evaluating the Capabilities of the Second Generation PICS Settling Column FlocCamera in a Muddy Tidal Estuary, York River, Virginia, USA

Grace M. Cartwright, S. Jarrell Smith ,

Carl T. Friedrichs, and Kelsey A. Fall

US Army Corps of Engineers

Engineer Research and Development Center

Waterways Experiment Station

Vicksburg, MS


Motivation

Motivation

An Example Set of Bursts

Independent verification

Acoustic Doppler Velocimeter (ADV) Method

Bulk Settling Velocity (Ws) of suspended sediment

<C> is burst averaged concentration from calibrated ADV backscatter

<w’C’> is burst averaged Turbulent Reynold’s Flux

Cbackgroundis the lowest concentration observed during the study period

ADV

Concentration(mg/L)

<w’C’> (mm/s)(mg/L)

Bulk

Bulk Settling Velocities for MUDBED Tripod Deployments

(Dickhudt et al, 2009; Cartwright et al, 2011; Fugate and Friedrichs, 2002)


Pics particle imaging camera system

PICS – Particle Imaging Camera System

Laser source

settling column

camera

Laser source

Side View

1mm light sheet

10 x 14 mm

Current

Top View

(Smith- INTERCOH 2012)


Example pics video sequence 1 m depth

Example PICS Video Sequence (1 m depth)

10/06/2012 14:06:00 (frames 001-080) collected at 8 frames/sec

Fluid Velocity hinders sediment settling


Grace m cartwright s jarrell smith carl t friedrichs and kelsey a fall

PTV/PIV method to remove fluid velocity effects

PTV: Particle Tracking Velocity

individual particles ≥ 30 μm (3 pixels)

PIV: Particle Image Velocity

groups of particles ≤20 μm (2 pixels)

Fluid velocities

estimated for each cell from one frame to the next

Particles are tracked from frame to frame

A Thread is a particle tracked for at least 5 frames

Peak velocity used

for each cell

(Smith and Friedrichs, 2012;Van Leussen and Cornelisse, 1993; Fennessy et al, 1994)


Ptv piv method to estimate ws s and mass

PTV/PIV method to estimate Ws, ρsand mass

Calculated as the net of the Particle and fluid velocity vectors

Averaged for all the frames in the track

Particle Density

Split into 3 classes: Density

1. primary > 1800 kg/m3

2. bed aggregate 1150-1800 kg/m3

3. flocculants < 1150 kg/m3

(Smith and Friedrichs, 2012; Oseen, 1927; Schiller and Naumann, 1933; Soulsby, 1997,)


Grace m cartwright s jarrell smith carl t friedrichs and kelsey a fall

NSF MUltiDisiplinaryBenthic ExchangeDynamics

Clay Bank area on York River Chesapeake Bay, VA

Micro tidal ( 0.7 to 1 meter)

Study Site

Secondary Channel

~ 5 meter depth

Seabed During Neap

>75% mud

~10% Organics

Sand D50 ~100 µm

up to 30% Pellets (~60-90 μm)

Kraatz, (2010, personal comm), Rodriguez-Calderon (2010)


Grace m cartwright s jarrell smith carl t friedrichs and kelsey a fall

October 6, 2012

2 days before Neap

Slack-Slack bracket Flood (~6 hrs)

Study Period

Every Hour

Water column “cast” 5-6 samples (~1/m)

Bottom samples every 10-15 min

Each Sample

PICS

Turbulence dissipate 15-30 sec

Collect 30 sec burst @ 8 frames/sec

Collect second burst ~1 min later

ADV

2 minute burst @ 10 Hz

LISST

2 minute burst@ 2/3 Hz

CTD

2 minute burst@ 1 Hz

Pump Samples

1 sample right away

2nd sample mid CTD burst

(Picture from Smith and Friedrichs, 2010)

Two Grab Samples of Bottom Sediment


Grace m cartwright s jarrell smith carl t friedrichs and kelsey a fall

20121006084703.seq

08:47:03

Example PICS Results

Depth 5.8 m

Number particles 400

d50,p= 54.7 μm

d50,m = 68.1 μm

ws50,p = 0.172 mm\sec

ws50,m = 0.239 mm\sec

By particle count

Flocs: 75.5 %

Bed Agg: 24.5 %

Primary: 0.0 %

By mass

Flocs: 78.0 %

Bed Agg: 22.0 %

Primary: 0.0 %

3 classes: Density

1. primary > 1800 kg/m3

2. bed aggregate 1150-1800 kg/m3

3. flocculants < 1150 kg/m3


Grace m cartwright s jarrell smith carl t friedrichs and kelsey a fall

Preliminary Results

Concentrating on bottom samples only


Grace m cartwright s jarrell smith carl t friedrichs and kelsey a fall

Water Velocity from ADV


Grace m cartwright s jarrell smith carl t friedrichs and kelsey a fall

% >60 μm (by weight) from Pump Sample SPM

% SPM > 60 μm


Grace m cartwright s jarrell smith carl t friedrichs and kelsey a fall

50 percentile grain-size from PICS

For each sample -- 30-sec bursts approximately 1 minute apart


Grace m cartwright s jarrell smith carl t friedrichs and kelsey a fall

50 percentile settling velocity from PICS

For each sample -- 30-sec bursts approximately 1 minute apart


Grace m cartwright s jarrell smith carl t friedrichs and kelsey a fall

Bulk settling velocity from PICS and ADV

For each PICS sample -- 30-sec bursts approximately 1 minute apart


Grace m cartwright s jarrell smith carl t friedrichs and kelsey a fall

Future Work

  • Work up LISST data

  • Process the bottom sediment

  • Repeat Study for Spring Tide

  • PICS lab experiment to find

  • Ws for isolated fecal pellets

(Figure from Smith and Friedrichs, 2010)


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