What is the most powerful erosional agent?
Water Erosion Water is the most important erosional agent and erodes most commonly as running water in streams. However, water in all its forms is erosional. Raindrops (especially in dry environments) create splash erosion that moves tiny particles of soil.
What is the concept of graded stream?
A graded stream is a system in equilibrium, one in which there exist a balance of the erosional and depositional processes. It is a stream that is transporting just that amount of sediment it is capable of, for its velocity and discharge.
Where does the water flow the fastest?
Usually the speed of river water is fastest in the upper reaches. It becomes slower at the middle reaches and the slowest at the lower reaches. In the same place of the same river, the speed of the current also differs. Where a river runs straight, the current is faster in the center and slower near the riverbank.
What does it mean when a stream has a graded profile?
A graded stream stream has a smooth concave-upward longitudinal profile from the base level to the headwaters without any breaks (e.g. waterfalls, rapids) in the profile. A graded stream profile is one where a dam has created a change in the longitudinal profile of a stream. Graded stream profiles are not flat.
What is the meaning of graded profile?
A stream is said to be at grade when it is neither eroding nor depositing material at any point along its course. A smooth concave profile, flattening downstream, is usually taken therefore to be typical of a graded stream.
What is graded profile?
A graded stream has a long profile that is in equilibrium with the general slope of the landscape. A graded profile is concave and smooth. Stream’s maintain their grade through a balance between erosion, transportation, and deposition.
What is a graded condition?
Grade is a condition of equilibrium in streams as agents of transportation. Slope usually decreases in a downvalley direction, but because discharge, channel characteristics, and load do not vary systematically along the stream, the graded profile is not a simple mathematical curve.
What does B condition mean?
A Grade B product will be in an okay condition with marks and scratches noticeably visible to the user, including shiny keys and surfaces around the keyboard. They are refurbished products where there are signs of previous use, but the functionality remains the same as Grade A products.
What is Grade C condition?
Refurbished Grade C is the lowest quality of a refurbished phone or laptop that is still in working order. Although refurbished Grade C devices have been tested and are confirmed to work, they do show signs of heavy or even excessive usage by their previous owner.
What are the three main zones of a river system from highest to lowest?
Three zones are usually recognized – headwaters, where flow is usually lowest of any where along the system, slope is often steepest, and erosion is greater than sediment deposition; transfer zone, the middle range of the stream where slope usually flattens somewhat, more flow appears, and deposition and erosion are …
What factors would decrease flow velocity?
Factors Affecting a River’s Velocity
- Channel Shape. The shape of the channel affects the velocity of a river.
- Volume of Water. The volume of water that flows through a river within a given amount of time — known as the discharge — also affects its velocity.
- Smooth and Rough Channels.
- Riverbed’s Gradient.
What serves as the ultimate base level for streams?
The ultimate base level is sea level – streams will not erode their channels below their base level. Many temporary base levels can exist along a stream’s path. Erection of a dam results in creation of a lake which serves as the temporary base level for the up stream part of the river.
What is used to calculate a stream’s discharge?
Discharge = V x D x W If length is measured in feet and time in seconds, Discharge has units of feet3/sec or cubic feet per second (cfs). Depth times Width gives the cross-sectional area. The shape of the channel is important because of the reduction in velocity due to friction along the channel margins.
How do you calculate specific discharge?
the actual flow velocity v may be calculated with the following formula: v=Q/(A*f)=q/n, n is the porosity, and q the specific discharge. if the porosity n is 30%, the flow velocity in the example above is 10.5 m/y.
How is discharge flow rate calculated?
From cross-section and average speed. The flow rate of a stream is equal to the flow velocity (speed) multiplied by the cross-sectional area of the flow. The equation Q=AV (Q=discharge rate, A=area, V=velocity) is sometimes known as the discharge equation.
Are discharge and flow rate the same?
The amount of fluid passing a section of a stream in unit time is called the discharge. If v is the mean velocity and A is the cross sectional area, the discharge Q is defined by Q = Av which is known as volume flow rate. Discharge is also expressed as mass flow rate and weight flow rate.
What is the unit of rate of flow of discharge?
Flow rate or discharge, Q, is the volume of water in cubic feet passing a flow section per unit time, usually measured in cubic feet per second (ft3/s).
What increases river discharge?
As the rain starts to get heavy, the soil may be saturated, thus there is an increase in surface run off. This causes water to start flowing into the river channel, causing the level of discharge to increase, making the line go up positively.