How does the type of terrain in a watershed affect flooding or erosion?
The height and steepness of the hills, floodplains and channels contribute to the erosive power of the water in a watershed and its stream channels. Steep slopes allow the force of gravity to quickly accelerate the speed of flowing water.
How does erosion affect watersheds?
Erosion and sedimentation can also have these affects: Loss of fertile top soil. Flooding from clogged ditches, culverts, and storm sewers. Muddy or turbid streams.
How does flooding affect watersheds?
Agents of Natural Change in Watersheds
During particularly intense floods entirely new channels can form, riparian forests can be displaced, and major landslides and debris torrents can be triggered, leading to a more extensive ecological recolonization and recovery period.
What are the some factors that will affect the amount of water in watersheds?
The physical characteristics of a watershed, including geology, soil types, vegetation, topography and slope, also influence water- shed water quality. Minerals contained in some rocks can dissolve in water and as a result, change the water's chemistry.
How does the slope of the land affect the flow of water in a watershed?
In general, the steeper and longer a slope is, the faster water runs off of it, and the greater potential there is for erosion. But many other factors come into play in determining what becomes of a slope over time when exposed to storm water runoff.
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How does land use affect the watershed?
Impacts of Land Use on Watershed Resources
Constructing swimming pools, buildings, roads, sidewalks, parking areas and other features that are "impervious" (do not allow water to penetrate through them and into the underlying soils) eliminate ground water recharge and convert that volume of water to stormwater runoff.
How land slope affects erosion?
As the slope increases, the type of erosion changes, chiselling the ground into different shapes and thereby increasing the surface area - and hence the number of pores that can absorb water, at least in the initial phase.
How does topography affect watersheds?
For example, topography can determine when surface flow and subsurface flow enter into stream. Steep topography could result in quick response . With the increase of mean slope in the watershed, subsurface flow and quick flow proportions could increase, whereas surface flow proportion could decrease .
What factor is the largest influence in how water drains in a watershed?
Precipitation: The greatest factor controlling streamflow, by far, is the amount of precipitation that falls in the watershed as rain or snow. However, not all precipitation that falls in a watershed flows out, and a stream will often continue to flow where there is no direct runoff from recent precipitation.
How do watersheds prevent flooding?
They capture rushing flood water and hold the water back allowing it to be slowly released downstream. Slowing the water down and allowing it to be gradually released reduces damage to roads, bridges, fences, cropland and other property.
How do watersheds affect the environment?
Healthy watersheds provide many ecosystem services including, but not limited to: nutrient cycling, carbon storage, erosion/sedimentation control, increased biodiversity, soil formation, wildlife movement corridors, water storage, water filtration, flood control, food, timber and recreation, as well as reduced ...
How do watersheds prevent floods?
Plants and trees slow the rainwater, help it spread and sink into the ground, and prevent it from carrying off too much soil. this activity helps people understand how a watershed works and how all things within a watershed are important to the health of all the people living in the area.
How does soil erosion by water cause floods?
When it rains in the mountainous areas, the soil gets washed away towards the plains. The running water deposits the mineral-rich soil in the riverbed and over the years this deposition of soil can change the course of the river. This can lead to floods which cause the destruction of life and property.
What is the cause of water erosion?
What causes water erosion? Erosion is caused by the impact of raindrops on bare soil and by the power of running water on the soil surface. Natural erosion rates depend on inherent soil properties, slope, and climate, which together determine the ability of the site to support vegetation.
How does erosion affect water?
It has led to increased pollution and sedimentation in streams and rivers, clogging these waterways and causing declines in fish and other species. And degraded lands are also often less able to hold onto water, which can worsen flooding.
Why do mountains and elevation changes dictate the range of a watershed?
The elevation above sea level determines how much potential energy the water has. The farther above sea level the water is, the more potential energy it has. As water moves downstream, its potential energy is converted to kinetic energy - the energy of motion.
How does land use affect drainage basin?
Humans disrupt the drainage basin cycle by accelerating processes, (deforestation, changing land use) and creating new water storage reservoirs or by abstracting water. It is mainly human changes to: rivers and drainage. the character of the ground surface (its shape, texture and covering)
How do rivers affect watersheds?
A watershed – the land area that drains to a stream, lake or river – affects the water quality in the water body that it surrounds. Healthy watersheds not only help protect water quality, but also provide greater benefits than degraded watersheds to the people and wildlife that live there.
How does topography affect water movement?
Topographic gradients control the rate at which soil water moves downslope, thereby determining whether stormwater is flushed to the channel network or retained in the soil post-event (Figure 1).
How does topography affect drainage?
This information is useful in determining surface and subsurface drainage patterns. For example, sloping convex areas typically have good surface and subsurface drainage away from the area, while concave sloping areas such as potholes, drainage ways, and foot slopes are more likely to possess wetter soil conditions.
How does slope affect erosion and deposition?
Lesson Summary. Water flowing over Earth's surface or underground causes erosion and deposition. Water flowing over a steeper slope moves faster and causes more erosion.
Does the kind of soil affect the rate of water erosion?
Generally, soils with faster infiltration rates, higher levels of organic matter and improved soil structure have a greater resistance to erosion. Sand, sandy loam and loam-textured soils tend to be less erodible than silt, very fine sand and certain clay-textured soils.
Which slope has the highest erosion rate?
The greatest erosion rates were at upper positions on northern slopes, and upper positions on south slopes had relatively lower erosion rates.
How does land cover impact a watershed and the quality of water?
Many people have suggested that water quality deterioration begins when 10% to 20% of the watershed area is impervious. Studies in many areas of the country have found that concentrations of various contaminants increase with increasing impervious cover, while stream biodiversity decreases.