sediments transportation hydrology

Why are sediment transport and deposition?

By: Laiba Sarwar

Why are sediment transport and deposition important?

Many ecosystems benefit from sediment transport and deposition.

Sediment builds aquatic habitats for spawning and benthic organisms .

It is also responsible for providing nutrients to aquatic plants, as well vegetation in near shore

ecosystems.

Sediment and aquatic life:

Sediment deposition creates habitats for aquatic life

While too much sediment can be

detrimental.

Too little sediment can also diminish

ecosystem quality.

Where Does Sediment Come From?

Sediment comes from geologic, geomorphic, and organic factors.

The amount, material and size of the

transported sediment.

Sum of these influences in any particular

waterway.

A body of water surrounded by swampland will be inundated with decomposing organic material.

Factors that influence sediment transport:

Water flow

Water flow also called water discharge, is the single most important element of sediment transport.

The flow of water is responsible for picking up, moving and depositing sediment in a waterway.

Water discharge can be simplified as area (a cross-section of the waterway) multiplied by velocity, or as a volume of water moved over time.

Weather Events

Precipitation causes water levels to initially rise, and then return to previous levels (base flow) over the course of hours or days.

Heavy rainfall over an area of loose soil and minimal vegetation will create runoff, carrying loose particles into the waterway.

Anthropogenic factors, such as dams and altered land use

Dams affect the water flow through complete detention or

restricted channels.

The restricted flow can cause the channel downstream of the

dam to become “sediment-starved”.

Human influence

Sediments in drinking water

Sediments as contaminants

Sediment is one of the most common drinking

water contaminants. Sediment normally occurs due to organic or inorganic

matter being carried by wind or runoff into open

water sources.

Type of sediments in water

• Organic sediments

• Inorganic sediment

Brown or orange colored sediment particles in water are usually rust

particles that stem from corroded

water pipes and plumbing

• Dissolved minerals, such as iron and manganese,

may also precipitate, leaving traces of

sediment• Black sediment can

indicate a high level of manganese in the water, or it could stem from a more local source, such as corroded steel piping

• White or tan sediment in drinking water is usually a result of calcium carbonate and magnesium carbonate, commonly known as pipe scale.

• This determine hardness and softness of water

Other metals in water

• Arsenic is a semi-metal

element • . It is odorless

and tasteless

It enters drinking water supplies from

natural deposits in the earth or

from agricultural and industrial

practices.

Arsenic

Asbestos

• Asbestos is a naturally occurring mineral

• from corroded asbestos-cement pipes

in the distribution system.

Uses of asbestos inproduction of cements,

floor tiles, paper products, paint,

This inorganic metal occurs naturally in the ground and

is often used in electrical equipment and electrical components. It generally

gets into water from run-off from mining operations,

discharge from processing plants and improper waste

disposal.

Beryllium