Drainage Density and Stream Order in a Drainage Basin
Drainage Density represents an approach to the quantitative analysis
of drainage basin. It is the average length of channel per unit area
of the drainage basin. It is calculated as shown below. Drainage
density is a qualitative analysis of the areal properties of a river
basin .
Drainage density is useful as a measure of frequency and spacing of
streams within the drainage basin. It also helps to determine the
texture of dissection of a drainage basin- the extent to which the
landscape is cut into by river valleys and in turn influence slope
development. Generally, there are 4 categories of drainage density and
corresponding texture of dissection.
Very low- less than 8km/km sq coarse
Medium low- 8-20 medium
High density- 20- 200 fine
Very high density- more than 200 ultra fines
Drainage density and texture of dissection varies in response to these
factors:
* Permeability of surface- a highly permeable material such as sand
tends to give low drainage density because of high infiltration
capacity and little water is available as surface runoff to
maintain channels.
* Rock type
* Topography
* Vegetation- dense vegetation helps to intercept rainfall, because
of infiltration capacity and prevent overland flow. This will
inhibit channel development and thus the reduction of drainage
density.
* Rainfall amount, intensity and duration
* Human activities
* Time
Stream order refers to stream hierarchy- the way the various stream
channels in drainage fit together. Identification of the link in ...
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increase in peak flood flows of a river. The below shows the contrast
between storm hydrographs of an area before and after urbanizations. A
flashier storm hydrograph will make the area more prone to flooding.
Chinese experts believe that local deforestation, uncontrolled
building and lack of flood control have led to massive floods that
threaten loves and homes of millions.
Clearing of land for cultivation may cause soil erosion which result
in large quantities of sediments being moved into channels and
floodplains. Mining can also lead to very major change in channel
morphology. As mining often requires the use and deposition of large
quantities of water, thus high amount of waste is moved to rivers.
Both human activities may lead to the aggradations of the channel
bed- the building up of land surface.
Floods can be a very dangerous natural disaster because a flood has the power to move cars, buildings, and cause massive damage to life and property. Even the small floods that are only 30 centimetres or so can do massive damage to houses and if the
Depending on the type of path that was created, it would largely influence the rate and distance to which the sediment was transported.
The one feature common to the Hoover Dam, the Mississippi River and the Three Gorges Dam is that they all try to control nature’s swings, specifically in the form of flooding. Before the Hoover dam was built, the Colorado river “used to flood spectacularly.but after 1900 the Colorado provoked a vehement response” (Pg 177). The response was simple, but large. The U.S. built several large dams, including the Hoover dam, on the Colorado to decrease its flooding and increase power and irrigation. Unfortunately, just as human control of the Colorado’s flooding increased, its organisms and habitats were detrimentally influenced, and the water became more and more salinated.
An epidemic of water born diseases in Chicago was rampant in the early 1880s. In order to stop the spread the diseases, Chicago exercised their right to reverse the flow of the once stagnant river, thus saving the lives of Chicago residents.
Over time an oxbow lake may become filled with organic material and be transformed into a marsh. In conclusion hydraulic variables and physical variables (relief/climate) aid the development of depositional landforms along a river. The more turbulent a river is, the more it will occur. The turbulence differentiates through the three courses; upper, middle and lower.
How does the bare soil surface type affect the amount of runoff? Speculate why this happens.
In Tim O’Brien’s “On the Rainy River”, the environment and it’s surroundings are correlated to the daily life and emotions of Tim O’Brien. These locations each represent a mental state in which Tim is using as his cognition for the events around him. For example, both Canada and Minnesota represent the two ideals Tim struggles with. In Canada, Tim attains the freedom from the Vietnam war he desires, but also leaves his family his family and friends in the shadows of humiliation. Meanwhile, Minnesota represents the war he believes is unjustified; where he must live and fight for, although he does not want to see many mutilated bodies from his homeland. Both Canada and Minnesota are representations of where Tim can go but also represent his
The amount of runoff depends on the surface of the Earth. If you have something like pavement you're prone to have more runoff. If you have something like soil, you're prone to have less runoff. Runoff can also be affected by slopes and the ground material.
What is courage? Is courage a feeling? Is courage a memory? Being a coward is one of the worst feelings experienced, that is why Tim O’Brien felt uneasy after he arrived back from the war. In the story “On the Rainy River”, by Tim O’Brien, O’Brien was to fight in the Vietnam war, he did not want to go to war as he did not throughly understand the reason for it. In “On the Rainy River”, by Tim O’Brien, O’Brien felt cowardly as he was hesitant of the causes and effects of the war, he could have escaped to Canada, and he only went to the war in fear of humiliation from others.
"Step 1. Characterizations of the Watershed." Forest Service: 17 pars. Viewed 7 Nov. 2002. <http://www.fs.fed.us/r2/psicc/spl/south_platte_web/step_1.htm>.
Introduction: Rainwater runoff, also called non-point source, is everywhere, especially in the artificial concrete communities that we live in. Rainwater runoff occurs after rain showers and thunderstorms, when the water flows down streets, sidewalks and gutters. There is so much rainwater runoff now a day because of the colossal neighborhoods and buildings and parking lots we are creating. The runoff happens when the water can’t soak into the ground, like it naturally does. With growing cities and industrialization, runoff water is becoming more and more of a problem and people need to start worrying about it. Runoff water has the possibility of becoming very dangerous, depending on what the water takes with it. Pesticides, garbage, bacteria, sediments from roads, feces and oil/gasoline are just some of the many substances that rainwater runoff carries with it on it’s journey; and lets not forget about all of the possible toxic chemicals that would fall into its path. So many residencies have been built, causing more runoff water because it isn’t being absorbed into the soil, since the soil is covered in concrete or other substances that were used to build. Everything that rests in gutters also goes down into the soil and in sewers that dump water into soil or other bodies of water, and the effects can both be positive and negative. Substances such as phosphate can travel with the runoff water into areas with soil and grass, causing it to grow faster. While some people may think fast growing grass is helpful, lets not forget about the rest of the environment the phosphate can effect. Certain algae’s can be harmful to humans when ingested. After knowing that, people should realize that it is time for environmental management to co...
Storm Water Drainage: This is simply the water from rain, melted snow, etc. draining into
For decades tourists and local beach goers have been flocking to Southern California in search of an inviting environment to relax and enjoy all the amenities a coastal climate has to offer. Yet despite the beauty and breathtaking atmosphere, many unforeseen factors may alter your perspective in regards to how frequently you visit these beach locations. In its current state many beach destinations surrounding the Orange County, California area are susceptible to urban runoff bringing copious amounts of pollution to the waterfront. As it stands urban runoff is attributing to the decline of water quality in numerous locations like Doheny Beach and Poche Beach, which for several years now have remained present on Heal the Bay’s Top 10 Beach Bummers list. With two of Orange Counties own beaches being present on the Top 10 list, it is now apparent that there is a breakdown in the system in regards to policies responsible for controlling runoff headed to the ocean.
the the change in sea level is due to a change in the level of land
Urbanization: Soil is considered as water reservoir. Urbanization acts in creating amount of impermeable surface due to construction of buildings, roads, drainage, sewage, flood relief channel etc. It reduces the amount of infiltration and percolation. Water tends to experiment the runoff process rather than infiltration. This contributes to increase in