06 Sediment Measurement

Prepared by: SURIPIN, MAGISTER TEKNIK SIPIL UNDIP

SEDIMENT TRANSPORT

SEDIMENT MEASUREMENT


MEASUREMENT OF SUSPENDED LOAD1. Suspended Sediment Sampling

1) Vertical Concentration Gradient2) Sampling Location3) Depth-Integrating Sampler4) Point Integrating Sampler

2. Continuous Turbidity Measurement1) Type of Turbidimeters2) Relationship between Turbidity and Suspended Solids3) Limitations of Turbidity Data

3. Bed Load Sampling1) Bed Load Transport2) Bed Load Sampling3) Continuous Bed Load Measurement


• The US DH-95TM weighs approximately 29 lbs. and is 22 inches in length from the tip of the intake nozzle to the rear of the tailfin or 17 inches with out the intake nozzle and bottle.

• The unsampled zone, the distance between the centerline of the nozzle and the streambed, is 4.8 inches. The sampler is designed to use a one liter Teflon or plastic bottle adapted to the US D-95 CapTM or US D-77 sampler cap and nozzle. The bottle cavity is machined from a low-lead bronze casting and is coated with plastic. The tail section is constructed from a plastic.

MEASUREMENT OF SUSPENDED LOAD1. The US DH-95TM is a light-weight suspended-sediment/water-quality

sampler capable of being used as a hand-line sampler. 2. It is approximately the same size as the US DH-59 and US DH-76 samplers.

Neither the US DH-59 or US DH-76 can meet the standards for a "clean" water-quality/suspended sediment samplers.


This sampler is equipped with a tail vane assembly to orient the intake nozzle of the sampler into the approaching flow as the sampler enters the water. The sample container is sealed against a gasket in the head cavity of the casting by pressure applied to the base of the bottle by a hand-operated spring-tensioned pull-rod assembly at the tail of the sampler. Suspended-sediment samples, collected by the intake nozzle projecting horizontally upstream from the head of the casting, are discharged into the bottle containers.

Depth-Integrating Suspended-Sediment Sampler Model DH 59

MEASUREMENT OF SUSPENDED LOAD


SNI 3414:2008

Tata cara pengambilan contoh muatan sedimen melayang di sungai

dengan cara integrasi kedalaman berdasarkan pembagian debit


Methods of Sampling• Depth Integrating Method:

– Water depth < 4.5 m two direction (up and down)– 4.5 m < Water depth < 9 m one direction– Water Depth > 9 m vertical should be divided into some parts

• Point Integration Method:– Two points; one from surface and the other from the bottom– Three points; one from surface, second from mid‐depth and third

from bottom.– Two points; one from 80 % and the other 20% of water depth C

mean = 3/8*C1 + 5/8*C2



Frequency of Sampling:• Variations in the sediment load occur due to;

– Storm characteristics– Size, shape, geological and topographic features of

drainage area– Stream characteristics

• Sediments should be measured twice a week but sampling intervals can also be varied from day to a week during low and mean water or daily during floods.



Suspended Sediment Load Samplers

• Instantaneous Suspended Load Samplers

• Time Integrating Suspended Load Samplers– Point‐Integrating Suspended Sediment

Samplers– Depth‐Integrating Suspended Sediment

Samplers


The US DH-2A is an enhanced version of the US DH-2 sampler developed by the Federal Interagency Sedimentation Project (FISP).

The US DH-2A Sampler



Average annual sediment yield rate versus drainage area size. 103-D- 1806.


SUSPENDED SEDIMENT VS DISCHARGE

Qs= a Qwb

where:Qs = suspended transport, in tons

per day,

Qw = discharge, in cubic feet (cubic meters) per second,

a = coefficient, and

b = exponent.


Suspended sediment rating curve for Rio Too Vaco. Near Villalba, Puerto Rico. 103-D-1807.


BEDLOAD MEASUREMENT• Title: Small Bedload Sampler• Description: Named for co-inventors Ed

Helley and Winchell Smith; built in the 1960s by Vigus and Lyle, machinists in the Geology Department of the University of California, Berkeley. This sampler was first used in California and later at several locations around the country. Bedload samplers are used to sample sand, silt, gravel or rock debris carried by a stream or immediately above the stream bed. This sampler weighs 65 lb, larger versions weigh over 100 lb. Object ID: USGS-000760


Helley-Smith Bedload Sampler


Hydrological Services Handheld Bedload SamplerHand Held Sampler

• Easy to Use• Used for Wading Measurements• Field Sample Weighing System• Cast Aluminium Construction

SPECIFICATIONOrifice: 76mm x 76mmBody: Epoxy coated cast aluminiumWading Rods: (2 X 0.5 m ) Stainless SteelSections supplied as standard.Additional 0.5 m sections areavailable on requestSample Bag: Polyester mono filament bag of 0.2mm mesh - will not absorb water.Carry Bag: CanvasPacked Weight : 4 kgPacked Dimension: (700x300x300) mm

BEDLOAD MEASUREMENT


• The sediment grabber is a simple device, the sort of thing that shows up in Engineering Statics homework assignments: it's open as it drops to the bottom, because there's no force on the handles; when you pull up on the handles, it closes, trapping a chunk of mud and gravel (sediment) inside. Then you haul it back on the boat, dump the contents in a big box with a mesh bottom, and wash away the mud to eveal the biomass -- usually flatworms. (Ugh. I am so not a biologist.)

BEDLOAD MEASUREMENT


BEDLOAD MEASUREMENT

06 Sediment Measurement

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