WEBVTT

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Hello , I am Paul Schroder . I'm a

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research civil engineer in

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environmental lab at DIC . Today , I'm

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going to talk about the STF model ST

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fate models . The short term effects a

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dredge disposal in open water to

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predict deposition of dredge to on the

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sediment bed and the and the water

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quality effects in the water column .

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The first process is convective descent

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of the high density drug material plume

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during that descent waters and trained

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within the plum and portions of the

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plume are stripped from the plume to

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farm low density clouds in the water

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column . The second process involves

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the collapse of the plum on the

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sediment bed . During that time , water

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has been trained into the bed and

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material spreads laterally as the

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density flow . The third process is the

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transport and dispersion of the clouds

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that were formed during the descent and

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collapse on the bed . These clouds are

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transported by the current and then

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disperse by Gaussian diffusion . The

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program will predict the concentrations

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of the suspended solids in these clouds

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as well as their contaminants both in

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space and time material from these

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clouds are able to settle as well and ,

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and deposit on the bed . The program

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predicts the deposition of the material

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both from the collapse and from the the

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long term transport . It predicts it in

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terms of a mass per unit area . In

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addition , considering consolidation ,

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it predicts the thickness of these

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deposits . This slide shows

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the graphical user interface for the

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STF model . The program can be run for

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many different types of evaluations .

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Its primary use is to

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evaluate compliance with water quality

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criteria for open water disposal of

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dredge material . Shown here is a plot

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of a of a run where it's predicting the

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concentration of lead in the this

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judicial plume as a function of time

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shown here in yellow is the

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concentration of the plume shown here

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as a red dash line . It's the water

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quality standard and it illustrates

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that that it meets the water quality

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standard . You know , after about 45

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minutes , this output shows the mixing

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zone required for the discharge . This

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is the area enclosed by this is

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where the water quality criteria was

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succeeded throughout the during the

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simulation . The output also can uh the

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the pro the program will also provide

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you a calculation on the required

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mixing zone required for the disposal

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operation to meet to comply with water

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quality standards . Shown here is the

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just is the contour of the mixing zone .

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We're meeting the water quality

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standards inside the the

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figure here , the the the water quality

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is succeeded outside the water quality

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is met . This shows roughly that you

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need a 1400 ft

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long site to meet your compliant , to

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comply with the water quality criteria ,

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er , discovering , developing and

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delivering new ways to make the world

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safer and better every day .