Dredging Prism Data

The slurry density and pipeline velocity, production rate, x-, y-, z-positioning

of dustpan, pump vacuum, discharge pressure, and date and time parameters were

sampled every 10 sec. Prior to the demonstration, the contractor was already

using these parameters for dredge operation optimization (described in Chap-

ter 2). Minor software modifications by the contractor merged these parameters

into a common data stream provided to the USACE in a single, comma-delimited

data string for analyses. The header for this data string consists of the following

parameters and engineering units:

Date, time, pump vacuum (inches of mercury), pump 1 discharge pressure

(psig), pump 2 discharge pressure (psig), slurry specific gravity, slurry

velocity (ft/s), production rate (yd3/hr), dustpan easting (ft), dustpan

northing (ft), dustpan elevation (in ft referenced to MLG), and river stage

(ft).

Horizontal position (x-,y-coordinates) of the dustpan was determined by a

DGPS and reported in State Plane Coordinates. The z-coordinate (dustpan depth)

was calculated by measuring the dustpan depth relative to water level, then

correcting that value with the river stage referenced to MLG. Dustpan depth

relative to water surface was calculated by measuring the ladder angle with an

inclinometer and, by working through geometric relations between the measured

inclination angle and ladder geometries, producing a depth value. This value was

then corrected for draft and reported as depth relative to water surface. This

relative water depth was adjusted to MLG datum by river stage values manually

entered from readings taken from the MVN river stage board at Pilot Town.

The slurry density was measured by a nuclear density meter (Photo 26) and

pipeline velocity by a electromagnetic flow meter. The instantaneous production

rate (reported in cubic yards per hour) was calculated for each sample from the

slurry density and velocity values. Pump vacuum and discharge pressures were

measured by pressure transducers mounted on the pipeline. Date and time values

were taken from the data collection computer clock set to the local time zone.

The leverman logs and daily observation logs were manually recorded by

USACE and contractor personnel in the leverman's room.

Dredging Prism Data

The dredging prism data listed in Table 1 were collected to reference the

dustpan digging elevation and hydrographic surveys to MLG and define hydro-

dynamic conditions in which the dredging was conducted (respectively river

stage and current measurements), to determine sediment type and grain size in

Reaches 1 and 2 (sediment samples), and to determine production rates and

identify shoaling (before dredge (BD) and after dredge (AD) hydrographic

surveys).

Chapter 3

Data Collection Program