1122 Lab 3(Surface Water) (AutoRecovered)
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Lab 3- Surface Water
GEOL 1122
Before answering the questions for each section, make sure you have watched the video(s). After
you have completed this worksheet, save it and upload it to the assignment folder for Lab 3 in iCollege. Please use your own words
to answer the questions, and include as much detail as possible
.
Lab Objectives
At the end of this lab, students should be able to:
Understand “where is water found and how much is there?” on a global scale
Name and explain major reservoirs and fluxes in the hydrologic cycle
Know the distinguishing features of wetlands and ponds/lakes
Understand how river velocity and sediment transportation capacity changes along a river
network and why these changes.
Understand the importance of urban stormwater infrastructure and how it relates to social
and environmental justice or the lack thereof Part 1: Introduction
To answer these questions, first watch the “Lab 3, Part 1: Introduction” video on iCollege. Please
answer the questions in your own words.
1)
Hypothesize a process by which water from the ocean moves to the land surface. Please give a detailed answer with your reasoning fully explained. (4 pts)
Water from the ocean moves to the land surface through water cycle which involves water movement between ocean, land, atmosphere and organisms. The water movement is through:
Evaporation: That is water evaporating from ocean by the sun changing its state from liquid to vapors.
Condensation: The vapors will then cool down and condenses to droplets, forming clouds.
Precipitation: Water vapors then unite to form larger droplets and eventually become heavy enough to come back to land in the form of rain, snow and hail.
Water getting to land: The land and the ocean then get the rains. It contributes to several water bodies on the land, including lakes, rivers, and groundwater. This is the location where ocean water reaches land.
Runoff & Infiltration: Rainfall that travels across the land surface, gathers in rivers and streams, and finally reaches the ocean as runoff. When precipitation seeps into the earth, it replenishes soil moisture and aids in the development of groundwater as infiltration.
Movement of Ground Water: Laterally moving groundwater can empty into rivers or other bodies of surface water before returning to the ocean.
Transpiration: Other than precipitation, water being absorbed by plants and then be released into atmosphere.
2)
Pick three of the fluxes listed on the right side of this slide. For each of the three fluxes you pick, please search the internet to explain the process, in addition to naming the two reservoirs involved. In other words, your answer needs to include the starting and ending reservoirs for this process
. (4 pts)
Precipitation
: Water vapors uniting and condensing to form larger droplets and eventually become heavy enough to come back to land in the form of rain, snow and hail.
Starting Reservoir: Atmosphere in the form of water vapor.
Ending Reservoir: Earth's surface that is oceans, land, rivers and lakes.
Evaporation
: Transition of water from liquid to gaseous state in the form of water vapors
due to heat by sunlight. Starting Reservoir: Atmosphere in the form of water vapor.
Ending Reservoir: Earth's surface that is oceans, land, rivers and lakes.
Transpiration: Water is absorbed by the plant through roots and then released in the atmosphere through leaves as vapors.
Starting Reservoir: Earth's surface that is soil and ground water.
Ending Reservoir: Atmosphere in the form of water vapor.
3)
Use the internet to find a lake or wetland in the state of Georgia. Please write a thoughtful, well-developed paragraph (of at least five sentences) describing this lake or wetland. Important things to include are: (1) How and when did this feature form? (2) What organisms use this feature as a habitat? (3) what social, historical, or economic functions does this feature serve? (6 pts)
One of the lakes in Ga is, Lake Lanier, a large reservoir in the north of the state, is one of the most well-known. With the completion of the Buford Dam on the Chattahoochee River in the 1950s, Lake Lanier was formed. Among its many applications are the generation of hydroelectric power, water supply, and flood control. Today, the lake is a popular recreational location offering boating, fishing, and camping. Lake Lanier is home
to a broad range of fish species, including largemouth bass, striped bass, and catfish. The lake also acts as a habitat for other organisms. The lake is a well-liked location for bird watching since it attracts ducks and migrating species. Because of its ability to attract tourists, encourage the development of real estate along its boundaries, and provide water
resources for the region's agricultural and civic needs, the lake has made a substantial economic contribution to Georgia. Because of its visual beauty and recreational opportunities, Lake Lanier attracts both locals and tourists and has been deeply ingrained in the social and economic fabric of the surrounding communities.
4)
Please answer whether or not you think you live within a watershed (please explain your reasoning
). (2 pts)
It is within a watershed, as I reside in Atlanta, Georgia. A watershed is a region of land where all runoff or precipitation ends up in a shared outlet, like a lake or river. Atlanta is situated in the Upper Chattahoochee River Watershed. The Chattahoochee River flows through Atlanta, and the water resources of the city contribute to this watershed in the form of lakes and streams.
5)
Please hypothesize whether or not it is possible for a piece of land to be part of more than
one watershed simultaneously (fully explain your reasoning). (4 pts)
It is possible for a piece of land to be included in more than one watershed at the same time. The fundamental notion of a watershed is that all water flows to a single, shared exit, such as a river, stream, or lake. The direction in which water flows is determined by the ridges or divides that separate watersheds. However, the topography of the area may be complex, with overlapping or related drainage patterns, leading to situations where a certain land area delivers water to more than one watershed. Land can occasionally be found in complex, topographically variable locations bordering two or more watersheds. Rainfall on this kind of terrain may ultimately reach many bodies of water in various directions. In certain ecosystems, there are linked lakes, rivers, or marshes. Human activities such as the construction of canals, drainage systems, or water diversion projects
can alter natural drainage patterns. A piece of land may therefore fall under more than one watershed. Additionally, a piece of land may contribute to multiple watersheds due to
erosion and changes in landforms over time that affect drainage patterns.
Part 2: Why Do Rivers Curve?
Watch the linked YouTube video “Why do Rivers Curve” in its entirety to answer these questions in your own words
.
6)
According to the video, how are mountain streams different from rivers and streams that run through plains? (4 pts)
The main characteristics that set mountain streams apart from plains rivers and streams are their rapid flow, steep grades, and increased turbulence. Mountain streams flow faster
because they originate at higher elevations and confront steeper slopes. Mountain streams
have higher energy and turbulence, which contributes to unique geomorphic features like rapids and waterfalls. Plains rivers and streams, on the other hand, frequently have softer gradients, which causes slower flow and more meandering patterns. The overall dynamics, sediment movement, and ecological features of the water bodies are influenced
by these terrain variations.
7)
Explain the process by which streams/rivers running through flat areas begin to curve. Please use as much detail as possible, and make sure to include the role that water
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velocity plays (i.e., make sure to describe how water velocity is different in different parts of the stream/river). (4 pts)
A river in a flat location usually follows a fairly straight path in the beginning.
Gravity causes water to flow in the direction of least resistance, downhill. The riverbed is
not perfectly regular, even in regions that appear to be level. Its bedrock, other characteristics, or the composition of the sediment may vary. The water's velocity varies within the river. Generally speaking, the channel's center experiences faster flow, while the banks experience slower flow. Friction between the water and the riverbed, with less friction in the center than on the sides, is what causes this fluctuation in velocity. Faster-
flowing water in the center of the channel has more erosive power and can transport larger sediment particles. Sediment is carried downstream by the water as it erodes the central riverbed. A helicoidal or corkscrew flow pattern is produced by the velocity distribution, which has slower flow near the banks and quicker flow in the center. The river meanders as a result of the lateral migration brought on by this helicoidal flow. Where the riverbank is steep, erosion on the outside of a meander curve produces a cut bank. Deposition forms a point bar with softer slopes on the inside of the bend. The process of meandering generates a positive feedback cycle. Water encourages more meandering and migration by eroding the cut bank. Along the meandering route, a succession of riffles that is shallower sections and pools the deeper areas, alternate over time. As the river continues to erode and deposit silt, meanders become increasingly noticeable. A meander may occasionally get so prominent that the river cuts through its neck, creating an oxbow lake.
8)
What is the relationship between the width of a stream/river and the distance between consecutive meanders? If the width of a stream is 3 meters, what is the expected length of
one S-shaped meander in this stream (explain how this was calculated)? (4 pts)
One S-shaped meander's length is 6 times the channel's width. Thus, the S-shaped meander will be 18 meters if the width is 3 meters. As the width increases the river will meander over a long time.
9)
Explain the formation of an oxbow lake in as much detail as possible. (4 pts)
The meandering course of a river is the first step towards the creation of an oxbow lake. A meander bend's outer bank becomes cut as a result of the river's erosion over time, while the inner bank becomes a point bar due to sediment deposition. The meander loop's
neck narrows as it keeps growing and migrating. Eventually, during flood episodes, the river erodes through the tight neck, leaving the meander alone and establishing a bypass. After then, the deserted meander becomes an oxbow lake that is crescent-shaped, isolated
from the main river channel.
Part 3: Streamflow
Watch the linked YouTube video “Streamflow” in its entirety to answer these questions in your own words.
10) Please define the following terms: headwaters, tributary, main channel, and delta/mouth. (4 pts)
Headwater: The beginning, source, or origin of a river system (the high gradient portion that is subject to erosion).
Tributary: More water is supplied by smaller streams that merge with a main river along the way.
Main Channel: The principal river or waterway into which tributaries flow.
Delta/mouth: The stream's terminus reaches a bigger body of water, usually a lake or the ocean. Low gradient and deposition (delta is the depositional landform) are its defining characteristics.
11) Please explain how sediment grain size changes from the headwaters to the mouth of a river system. Make sure to include how water velocity is involved with this. (4 pts)
Grain size of silt in a river system typically varies from the headwaters to the mouth. Because of the steeper gradients, water velocity is usually higher near the headwaters, where the river starts at higher elevations. The river can carry larger, coarser sediment particles due to its rapid velocity. The gradient frequently drops as the river flows downstream towards the mouth, which lowers the water velocity. Finer sediment particles
are deposited at lower velocities, leading to a downstream fining tendency where the grain size decreases gradually from the headwaters to the mouth.
12) Pause the video at the Hjulstrom Diagram presented at 3:54 and predict what will happen (at a flow velocity of 1 cm/second) for clay, silt, sand, and gravel (i.e., whether each of these will be transported, eroded, or deposited, or a combination). (4 pts)
According to the Hjulstrom Diagram, the fate of sediment particles changes with size at a
flow rate of 1 cm/second. Because clay is so fine, it tends to get deposited because the velocity is too low for it to be transported continuously. Since silt is finer than sand, it may be subject to both deposition and transport, depending on turbulence, among other variables. At this velocity, sand with coarser particles is usually conveyed in suspension. Even coarser than sand, gravel tends to settle because the velocity is usually too low to maintain the suspension of these larger particles. 13) List the reasons given in the video for why stream velocity generally increases with distance downstream (4 pts)
There is an increase in stream velocity because the channel size increase along with the discharge and roughness of the channel decreases as we travel downstream. Sediment loads also increases until the sediments are deposited at the delta. And as the velocity of stream increases the transportation of sediments goes like boulders as the velocity
increases then can transport pebbles and with the stream having fast velocity can now transport the gravel. 14) First, give the definition of a hydrograph. (Note that while this video shows a period of months on the x-axis, hydrographs can be generated for any time period.) The graph below shows a hydrograph for a single storm event at Snapfinger Creek near Decatur, Georgia. The x-axis represents minutes since the start of the storm event. The y-axis represents discharge in units of cubic feet per second (although not metric, this is a unit for streamflow commonly used by the US Geological Survey). Using the diagram, locate peak discharge on this hydrograph and estimate the approximate magnitude (amount) of this discharge, as well as the approximate minute since the start of the storm event that this peak discharge occurred. (4 pts)
0
500
1000
1500
2000
2500
3000
3500
4000
4500
0
50
100
150
200
250
USGS 02203950 (December 28, 2012)
Time (minutes)
Discharge (CFS)
Peak Discharge = 220 CFS
Peak Discharge Time = 255 minutes
Part 4: Atlanta’s Proctor Creek
Read the linked article on iCollege in its entirety to answer these questions in your own words. 18) Summarize the reasons given in this article for the flooding problems and pollution that have long been associated with Proctor Creek. In your answer, hypothesize about how hydrologic processes in this watershed (that is mostly covered by concrete) are different from those in a forested watershed (hint: think about some of the fluxes listed in the introduction video) (4 pts)
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The ongoing issues with floods and pollution in Proctor Creek, Atlanta, are largely the result of past decisions made on urban development. The construction of the city includes
a lot of pavement and development, especially in the downtown Gulch region. Proctor Creek, which rises in the Gulch and passes through populated areas, has problems because rainwater does not naturally seep into the ground. Rather, after heavy rains, stormwater quickly travels over impermeable surfaces, strikes pavement, and enters sewers, overwhelming systems. Unlike a forested watershed where rainwater contributes to springs forming a creek, Proctor Creek's concrete-covered headwaters disrupt natural hydrologic processes, leading to downstream problems such as flooding, erosion, and pollution. Pollutants affect Proctor Creek and the neighboring neighborhoods, which leads to disinvestment and economic difficulties for the cleanup effort.
19) The US EPA defines the term “Environmental Justice” as follows: Environmental justice is the fair treatment and meaningful involvement of all people regardless of race, color, national origin, or income with respect to the development, implementation, and enforcement of environmental laws, regulations, and policies. EPA has this goal for all communities and persons across this Nation. It will be achieved when everyone enjoys the same degree of protection from environmental and health hazards and equal access to the decision-making process to have a healthy environment in which to live, learn, and work. Using this definition, write a well-developed paragraph (at least five sentences) about how residents in the neighborhoods comprising the Proctor Creek watershed have historically and are currently experiencing environmental injustice (8 pts)
Pollution and flooding issues are among the disproportionate number of environmental risks that affect the residents in the neighborhoods comprising Proctor Creek watershed in the Atlanta region. The occurrence of impermeable surfaces, industrial processes, and insufficient stormwater management systems lead to recurrent flooding that has an uneven effect on inhabitants, particularly in low-income areas. Pollutant flow into Proctor
Creek also aggravates problems with water quality, endangering the health of locals who frequently do not have equitable access to medical care. It is difficult for the historically underprivileged communities in this watershed to actively participate in the procedures that determine environmental laws and policies, which prevents them from having a voice and influencing decisions. In order to attain environmental justice within the Proctor Creek watershed, it would be necessary to tackle the existing imbalances, guarantee just treatment, and grant all inhabitants, regardless of their national origin, equal access to a healthy environment.