11 Water

Learning Objectives

By the end of this chapter, students should be able to:

  • Describe the processes of the water cycle
  • Describe basins, protection, and water budget.
  • Describe reasons for water laws, who controls them, and how water is shared in the western U.S.
  • Describe zone of transport, zone of production, zone of , and equilibrium.
  • Describe landforms: channel types, fans, floodplains, natural levees, deltas, , and .
  • Describe the properties required for a good ; define .
  • Describe three major groups of water contamination and three types of .
  • Describe topography, how it is created, and the landforms that characterize it.
Stone wall made up of two levels of thin arches
Figure 11.1: Example of a Roman aqueduct in Segovia, Spain.

All life on Earth requires water. The (Earth’s water) is an important agent of geologic change. Water shapes our planet by depositing , aiding , and altering rocks after they are lithified. Water carried by causes of upper material. Water is among the in and emerges at the surface as steam in .

Mayan stone figure with a long elephant-like nose representing a water deity.
Figure 11.2: Chac mask in Mexico.

Humans rely on suitable water sources for consumption, agriculture, power generation, and many other purposes. In pre-industrial civilizations, the powerful controlled water resources. As shown in the figures, two thousand year old Roman aqueducts still grace European, Middle Eastern, and North African skylines. Ancient Mayan architecture depicts water imagery such as frogs, water-lilies, water fowl to illustrate the importance of water in their societies. In the drier lowlands of the Yucatan Peninsula, mask facades of the hooked-nosed rain god, Chac (or Chaac) are prominent on Mayan buildings such as the Kodz Poop (Temple of the Masks, sometimes spelled Coodz Poop) at the ceremonial site of Kabah. To this day government controlled water continues to be an integral part of most modern societies. 

11.1 Water Cycle

A diagram depicting the continuous movement and transformation of water on Earth. The diagram shows a circular process with labeled arrows and key components: starting with the evaporation process, an arrow indicates water vapor rising from bodies of water into the atmosphere; condensation is represented by arrows showing the transformation of water vapor into clouds; precipitation is denoted with arrows indicating the falling of rain or snow from clouds back to the Earth's surface; surface runoff and infiltration are demonstrated by arrows showing water flowing over the land or seeping into the ground; arrows depicting the processes of plant uptake and transpiration are shown where water is absorbed by plants and released into the atmosphere through their leaves.
Figure 11.3: The water cycle.

The water cycle is the continuous circulation of water in the Earth’s . During circulation, water changes between solid, liquid, and gas (water vapor) and changes location. The processes involved in the water cycle are evaporation, transpiration, condensation, , and .

Evaporation is the process by which a liquid is converted to a gas. Water evaporates when solar energy warms the water sufficiently to excite the water molecules to the point of vaporization. Evaporation occurs from oceans, lakes, and  and the land surface. Plants contribute significant amounts of water vapor as a byproduct of photosynthesis called transpiration that occurs through the minute of plant leaves. The term  refers to these two sources of water entering the  and is commonly used by geologists.

Water vapor is invisible. Condensation is the process of water vapor transitioning to a liquid. Winds carry water vapor in the long distances. When water vapor cools or when air masses of different temperatures mix, water vapor may condense back into droplets of liquid water. These water droplets usually form around a microscopic piece of dust or salt called condensation nuclei. These small droplets of liquid water suspended in the become visible as in a cloud. Water droplets inside clouds collide and stick together, growing into larger droplets. Once the water droplets become big enough, they fall to Earth as rain, snow, hail, or sleet. 

Once has reached the Earth’s surface, it can evaporate or flow as into , lakes, and eventually back to the oceans. Water in and lakes is called surface water. Or water can also into the and fill the spaces in the rock or underground to become . slowly moves through rock and unconsolidated materials. Some may reach the surface again, where it discharges as springs, , lakes, and the ocean. Also, surface water in and lakes can again to . Therefore, the surface water and systems are connected.

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Video 11.1: Water cycle.

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11.2 Water Basins and Budgets

Schematic map view of a drainage basin: the main trunk stream has many branching tributaries and the drainage divide encircles all of the streams as a dashed red line.
Figure 11.4: Map view of a drainage basin with main trunk streams and many tributaries with drainage divide in dashed red line.

The basic unit of division of the landscape is the , also known as a or . It is the area of land that captures and contributes to a or segment. divides are local topographic high points that separate one from another. Water that on one side of the divide goes to one , and water that on the other side of the divide goes to a different . Each , and streamlet has its own . In areas with flatter topography, divides are not as easily identified but they still exist.

Oblique relief map of the Latorita River, a tributary of the Lotru River; North is toward the right of the map. The Latorita drainage basin is colored green and outlined in red; it encircles the main river as well as the tributary streams and surrounding land leading to the river.
Figure 11.5: Oblique view of the drainage basin and divide of the Latorita River, Romania.

The headwater is where the begins. Smaller combine downhill to make the larger trunk of the . The is where the stream finally reaches its end. The mouth of most streams is at the ocean. However, a rare number of do not flow to the ocean, but rather end in a (or ) where the only outlet is evaporation. Most in the Great Basin of Western North America end in . For example, in Salt Lake County, Utah, Little Cottonwood Creek and the Jordan River flow into the endorheic Great Salt Lake where the water evaporates.

World map with major drainage basins color-coded according to which ocean they lead to; the drainage basins leading to the Pacific Ocean are colored purple and cover western North America, a sliver along western South America, eastern and southeastern Asia, and northeastern and eastern Australia; the drainage basins leading to the Atlantic Ocean are colored green and cover eastern North America, central and eastern South America, western Europe, and western Africa; the drainage basins leading to the American Mediterranean Sea are colored olive green and cover central and southern North America and a tiny northern part of South America; the drainage basins leading to the Arctic Ocean are colored teal and cover northern North America, northern Europe, and northern Asia; the drainage basins leading to the Indian Ocean are colored pink and cover eastern Africa, southern Asia, and central and western Australia; the drainage basins leading to the Eurafrican Mediterranean Sea are colored blue and cover southern Europe and northern and central Africa; the drainage basins leading to the Southern Ocean are colored tan and covers all of Antarctica; and endorheic basins are colored gray and they are located in western and southern North America, southern South America, northern and central Africa, southern Africa, southern Asia, and central Australia.
Figure 11.6: Major drainage basins color coded to match the related ocean. Closed basins (or endorheic basins) are shown in gray.

Perennial flow all year round. Perennial occur in humid or temperate climates where there is sufficient rainfall and low evaporation rates. Water levels rise and fall with the seasons, depending on the . flow only during rain events or the wet season. In arid climates, like Utah, many  are These  occur in dry climates with low amounts of rainfall and high evaporation rates. Their channels are often dry washes or  for much of the year and their sudden flow causes . 

Along Utah’s Wasatch Front, the urban area extending north to south from Brigham City to Provo, there are several that are designated as “ protection areas” that limit the type of use allowed in those in order to protect culinary water. Dogs and swimming are limited in those because of the possibility of contamination by harmful bacteria and substances to the drinking supply of Salt Lake City and surrounding municipalities.

Water in the water cycle is very much like money in a personal budget. Income includes  and  and  inflow. Expenses include  withdrawal, evaporation, and  and  outflow. If the expenses outweigh the income, the water budget is not balanced. In this case, water is removed from savings, i.e. water storage, if available. , snowice,  moisture, and  all serve astorage in a water budget. In dry regions, the water is critical for sustaining human activities. Understanding and managing the water budget is an ongoing political and social challenge. 

Hydrologists create budgets within any designated area, but they are generally made for () boundaries, because and surface water are easier to account for within these boundaries. Water budgets can be created for state, county, or aquifer extent boundaries as well. The groundwater budget is an essential component of the hydrologic model; hydrologists use measured data with a conceptual workflow of the model to better understand the water .

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11.3 Water Use and Distribution

Map of the United States with water withdrawals per state in different shades of blue; low water withdrawals are lighter shades of blue while higher water withdrawals are darker shades of blue; California and Idaho have the highest water withdrawals; Oregon, Montana, Colorado, Nebraska, Texas, and Arkansas also have high water withdrawals; Washington, Wyoming, Nevada, Utah, Arizona, New Mexico, Kansas, Missouri, Mississippi, and Florida have lower withdrawals, and the rest of the 50 states have the lowest water withdrawals.
Figure 11.7: Agricultural water use in the United States by state.

In the United States, 1,344 billion liters (355 billion gallons) of ground and surface water are used each day, of which 288 billion liters (76 billion gallons) are fresh . The state of California uses 16% of national .

Utah is the second driest state in the United States. Nevada, having a mean statewide of 31 cm (12.2 inches) per year, is the driest. Utah also has the second highest per capita rate of total domestic water use of 632.16 liters (167 gallons) per person per day. With the combination of relatively high demand and limited quantity, Utah is at risk for water budget deficits.

Bar graph titled Trends in population and freshwater withdrawals by source, 1950-2010: the horizontal axis has years in 5-year intervals on the from 1950 to 2010; there are two vertical axes: the left vertical axis is labeled Withdrawals, in billion gallons per day and increases from 0 to 400, and the right vertical axis is labeled Population, in millions and increases from 0 to 350. Population increases over time while total water use increases at the beginning, peaks at 1980, and stays relatively steady until a decrease in 2010.
Figure 11.8: Trends in water use by source.

11.3.1 Surface Water Distribution

Fresh water is a precious resource and should not be taken for granted, especially in dry . Surface water makes up only 1.2% of the fresh water available on the planet, and 69% of that surface water is trapped in ground ice and . water accounts for only 0.006% of all freshwater and lakes contain only 0.26% of the world’s fresh water

Global circulation patterns are the most important factor in distributing surface water through . Due to the Coriolis effect and the uneven heating of the Earth, air rises near the equator and near latitudes 60° north and south. Air sinks at the poles and latitudes 30° north and south (see chapter 13). Land masses near rising air are more prone to humid and wet climates. Land masses near sinking air, which inhibits , are prone to dry conditions. Prevailing winds, ocean circulation patterns such as the Gulf Stream’s effects on eastern North America, rain shadows (the dry leeward sides of mountains), and even the proximity of bodies of water can affect local patterns. When this moist air collides with the nearby mountains causing it to rise and cool, the moisture may fall out as snow or rain on nearby areas in a phenomenon known as lake-effect .

Map of the United States showing distribution of precipitation in the United States. The western half of the United States is much drier than the eastern half of the United States with the exception of the Pacific northwest which has abundant precipitation.
Figure 11.9: Distribution of precipitation in the United States. The 100th Meridian is approximately where the average precipitation transitions from relatively wet to dry. (Source: U.S. Geological Survey)

In the United States, the 100th meridian roughly marks the boundary between the humid and arid parts of the country. Growing crops west of the 100th meridian requires irrigation. In the west, surface water is stored in and mountain snowpacks, then strategically released through a of canals during times of high water use.

Some of the driest parts of the western United States are in the Province. The has multiple mountain ranges that are oriented north to south. Most of the valleys in the are dry, receiving less than 30 c(12 inches) of per year. However, some of the mountain ranges can receive more than 1.52 m (60 inches) of water as snow or snow-water-equivalent. The snow-water equivalent is the amount of water that would result if the snow were melted, as the snowpack is generally much thicker than the equivalent amount of water that it would produce.

11.3.2 Groundwater Distribution

Water source Water volume (cubic miles) Fresh water (%) Total water (%)
Oceans, seas, and bays 321,000,000 96.5%
Ica caps, glaciers, and permanent snow 5,773,000 68.7% 1.74%
Groundwater (total) 5,614,000 1.69%
Groundwater (fresh) 2,526,000 30.1% 0.76%
Groundwater (saline) 3,088,000 0.93%
Soil moisture 3,959 0.05% 0.001%
Ground ice and permafrost 71,970 0.86% 0.022%
Lakes (total) 42,320 0.013%
Lakes (fresh) 21,830 0.26% 0.007%
Lakes (saline) 20,490 0.006%
Atmosphere 3,095 0.04% 0.001%
Swamp water 2,752 0.03% 0.0008%
Rivers 509 0.006% 0.0002%
Biological water 269 0.003% 0.0001%

Table 11.1: Groundwater distribution. Source: Igor Shiklomanov's chapter "World fresh water resources" in Peter H. Gleick (editor), 1993, Water in Crisis: A Guide to the World's Fresh Water Resources (Oxford University Press, New York).

makes up 30.1% of the fresh water on the planet, making it the most abundant of fresh water accessible to most humans. The majority of freshwater, 68.7%, is stored in and ice caps as ice. As the and ice caps melt due to global warming, this fresh water is lost as it flows into the oceans.

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11.4 Water Law

Federal and state governments have put laws in place to ensure the fair and equitable use of water. In the United States, the states are tasked with creating a fair and legal for sharing water.

11.4.1 Water Rights

Because of the limited supply of water, especially in the western United States, states disperse a of legal defined as a claim to a portion or all of a water source, such as a , , well, or lake. Federal law mandates that states control water rights, with the special exception of federally reserved water rights, such as those associated with national parks and Native American tribes, and navigation servitude that maintains navigable water bodies. Each state in the United States has a different way to disperse and manage water rights.

A person, entity, company, or organization, must have a to legally extract or use surface or in their state. Water rights in some western states are dictated by the concept of prior appropriation, or “first in time, first in right,” where the person with the oldest gets priority water use during times when there is not enough water to fulfill every .

The Colorado River and its tributaries pass through a desert region, including seven states (Wyoming, Colorado, Utah, New Mexico, Arizona, Nevada, California), Native American reservations, and Mexico. As the western United States became more populated and while California was becoming a key agricultural producer, the states along the Colorado River realized that the was important to sustaining life in the West.

To guarantee certain perceived water rights, these western states recognized that a water budget was necessary for the Colorado River Basin. Thus was enacted the Colorado River Compact in 1922 to ensure that each state got a fair share of the water. The Compact granted each state a specific volume of water based on the total measured flow at the time. However, in 1922, the flow of the was higher than its long-term average flow, consequently, more water was allocated to each state than is typically available in the .

Over the next several decadeslawmakers have made many other agreements and modifications regarding the Colorado River Compact, including those agreements that brought about the Hoover Dam (formerly Boulder Dam), and Glen Canyon Dam, and a treaty between the American and Mexican governments. Collectively, the agreements are referred to as The Law of the River” by the United States Bureau of Reclamation. Despite adjustments to the Colorado River Compact, many believe that the Colorado River is still over-allocated, as the Colorado River flow no longer reaches the Pacific Ocean, its original terminus (). Dams along the Colorado River have caused water to divert and evaporate, creating serious water budget concerns in the Colorado River Basin. Predicted drought associated with global warming is causing additional concerns about over-allocating the Colorado River flow in the future. 

The Law of the River highlights the complex and prolonged nature of interstate water rights agreements, as well as the importance of water.

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Video 11.2: The Colorado River Compact of 1992.

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The Snake Valley straddles the border of Utah and Nevada with more of the irrigable land area lying on the Utah side of the border. In 1989, the Southern Nevada Water Authority (SNWA) submitted applications for water rights to pipe up to 191,189,707 cu m (155,000 ac-ft) of water per year (an acre-foot of water is one acre covered with water one foot deep) from Spring, Snake, Delamar, Dry Lake, and Cave valleys to southern Nevada, mostly for Las Vegas. Nevada and Utah have attempted a comprehensive agreement, but negotiations have not yet been settled. 

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NPR story on Snake Valley

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SNWA History

Dean Baker Story

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Video 11.3: Transporting Snake Valley water to satisfy a thirsty Las Vegas.

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11.4.2 Water Quality and Protection

Two major federal laws that protect water quality in the United States are the Clean Water Act and the Safe Drinking Water Act. The Clean Water Act, an amendment of the Federal Water Pollution Control Act, protects navigable waters from dumping and point-source pollution. The Safe Drinking Water Act ensures that water that is provided by public water suppliers, like cities and towns, is safe to drink. 

The U.S. Environmental Protection Agency Superfund program ensures the cleanup of hazardous contamination, and can be applied to situations of surface water and  contamination. It is part of the Comprehensive Environmental Response, Compensation, and Liability Act of 1980. Under this act, state governments and the U.S. Environmental Protection Agency can use the to pay for remediation of a contaminated site and then file a lawsuit against the polluter to recoup the costsOr to avoid being sued, the polluter that caused the contamination may take direct action or provide funds to remediate the contamination. 

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11.5 Surface Water

Geologically, a is a body of flowing surface water confined to a channel. Terms such as , creek and brook are social terms not used in geology.  erode and transport , making them the most important agents of the earth’s surfacealong with wave action (see chapter 12) in eroding and transporting They create much of the surface topography and are an important water resource

Several factors cause  to erode and transport , but the two main factors are channel and velocity. channel  is the slope of the usually expressed in meters per kilometer or feet per mile. A steeper channel gradient promotes . When  forces elevate a mountain, the   increases, causing the mountain  to erode downward and deepen its channel eventually forming a valley. channel velocity is the speed at which channel water flows. Factors affecting channel velocity include channel which decreases downstream, and channel size which increase as tributaries coalesce, and channel roughness which decreases as lining the channel walls decreases in size thus reducing friction. The combined effect of these factors is that channel velocity actually increases from mountain brooks to the of the .

11.5.1 Discharge

size is measured in terms of , the volume of water flowing past a point in the over a defined time interval. Volume is commonly measured in cubic units (length x width x depth), shown as feet3 (ft3) or meter3 (m3). Therefore, the units of are cubic feet per second (ft3/sec or cfs). Therefore, the units of  are cubic meters per second, (m³/s or cms, or cubic feet per second (ft³/sec or cfs). increases downstream. Smaller have less than larger . For example, the Mississippi is the largest in North America, with an average flow of about 16,990.11 cms (600,000 cfs). For comparison, the average  of the Jordan  at Utah Lake is about 16.25 cms (574 cfsand for the annual  of the Amazon River(the world’s largest river)annual discharge is about 175,565 cms (6,200,000 cfs).

can be expressed by the following equation:

Q = V A 

  • Q =  cms (or ft3/sec), 
  • A = cross-sectional area of the  channel [width times average depth] as m2 (or in2 or ft2), 
  • V = average channel velocity m/s (or ft/sec)

At a given location along the , velocity varies with  width, shape, and depth within the  channel as wellWhen the stream channel narrows but  remains constant, the same volume of water must flows through a narrower space causing the velocity to increase, similar to putting a thumb over the end of a backyard water hose. In addition, during rain storms or heavy snow melt,  increases, which increases   and velocity.

When the  channel curves, the highest velocity will be on the outside of the bend. When the  channel is straight and uniformly deep, the highest velocity is in the channel center at the top of the water where it is the farthest from frictional contact with the  channel bottom and sides. In hydrology, the of a river is the line drawn that shows its natural progression and deepest channel, as is shown in the diagram. 

Stream velocity is higher on the outside bend and the surface which is farthest from the friction of the stream bed. The inside of the bend is a shorter distance than the outside. Longer arrows indicate faster velocity. In a river bend, the fastest moving particles are on the outside of the bend, near the cut bank.
Figure 11.10: Thalweg of a river. In a river bend, the fastest moving water is on the outside of the bend, near the cutbank. Stream velocity is higher on the outside bend and the water surface which is farthest from the friction of the stream bed. Longer arrows indicate faster velocity (Earle 2015).

11.5.2 Runoff versus Infiltration

Factors that dictate whether water will  into the ground or run off over the land include the amount, type, and intensity of ; the type and amount of vegetation cover; the slope of the land; the  and aspect of the land; preexisting conditions; and the type of  in the infiltrated area. High intensity rain will cause more  than the same amount of rain spread out over a longer duration. If the rain  faster than the ’s properties allow it to , then the water that cannot  becomes . Dense vegetation can increase , as the vegetative cover slows the water particleoverland flow giving them more time to If a parcel of land has more direct solar radiation or higher seasonal temperatures, there will be less and , as rates will be higher. As the land’s slope increases, so does because the water is more inclined to move downslope than  into the ground. Extreme examples are a and a cliff, where water much quicker into a than a cliff that has the same properties. Because saturated soil does not have the capacity to take more water, runoff is generally greater over saturated soil. Clay-rich cannot accept as quickly as gravel-rich .

11.5.3 Drainage Patterns

The pattern of tributaries within a region is called . They depend largely on the type of rock beneath, and on structures within that rock (such as and ). The main types of are dendritic, trellis, , radial, and deranged. are the most common and develop in areas where the underlying rock or are uniform in character, mostly flat lying, and can be eroded equally easily in all directions. Examples are or flat lying sedimentary rocks. typically develop where sedimentary rocks have been folded or tilted and then eroded to varying degrees depending on their strength. The Appalachian Mountains in eastern United States have many good examples of . patterns develop in areas that have very little topography and a of planes, , or that form a rectangular network. A forms when flow away from a central high point such as a mountain top or , with the individual typically having patterns. In places with extensive deposits, can disappear into the via caves and subterranean and this creates a .

Five schematic diagrams of stream drainage patterns: rectangular drainage shows streams curving at nearly right angles; dendritic drainage shows streams resembling tree branches; trellis drainage shows parallel ridge lines with streams between ridge lines; radial drainage shows streams radiating outward from a central high point; and deranged drainage shows curvy, erratic streams that appear and disappear.
Figure 11.11: Various stream drainage patterns.

11.5.4 Fluvial Processes

processes dictate how a behaves and include factors controlling production, transport, and . processes include velocity, slope and , , transportation, , equilibrium, and .

can be divided into three main zones: the many smaller tributaries in the source area, the main trunk in the and the distributaries at the of the . Major systems like the Mississippi are composed of many source areas, many tributaries and trunk , all coalescing into the one main draining the region. The zones of a are defined as 1) the zone of production (erosion), 2) the zone of transport, and 3) the zone of deposition. The zone of sediment production is located in the of the . In the zone of transport, there is a general balance between of the finer in its channel and transport of across the . eventually flow into the ocean or end in quiet water with a which is a zone of located at the of a . The of a is a plot of the elevation of the channel at all points along its course and illustrates the location of the three zones.

Zone of Sediment Production 

The zone of production is located in the of a where rills and gullies erode and contribute to larger . These tributaries carry and water further downstream to the main trunk of the . Tributaries at the have the steepest ; there produces considerable carried b the . Headwater tend to be narrow and straight with small or non-existent floodplains adjacent to the channel. Since the zone of production is generally the steepest part of the , are generally located in relatively high elevations. The Rocky Mountains of Wyoming and Colorado west of the Continental Divide contain much of the for the Colorado River which then flows from Colorado through Utah and Arizona to Mexico. of the Mississippi river system lie east of the Continental Divide in the Rocky Mountains and west of the Appalachian Divide.

Zone of Sediment Transport 

2D diagram with a brown stream bed at the bottom and a light blue stream above it; particles that move along the stream bed are labeled Bed load, particles that are carried in the stream without touching the stream bed are labeled Suspended load, and there is a label Dissolved load to show material dissolved in the water.
Figure 11.12: A stream carries dissolved load, suspended load, and bedload.

Streams transport great distances from the to the ocean, the ultimate depositional basins. transportation is directly related to and velocity. Faster and steeper can transport larger grains. When velocity slows down, larger settle to the channel bottom. When the velocity increases, those larger are entrained and move again.

Transported are grouped into , , and as illustrated in the above image. moved along the channel bottom are the that typically consists of the largest and densest particles. is moved by (bouncing) and traction (being pushed or rolled along by the force of the flow). Smaller particles are picked up by flowing water and carried in suspension as . The particle size that is carried in suspended and depends on the flow velocity of the . in a is the total of the ions in from , including such common ions such as bicarbonate (-HCO3), calcium (Ca+2), chloride (Cl-1), potassium (K+1), and sodium (Na+1). The amounts of these ions are not affected by flow velocity.

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Video 11.4: Bed load sediment transport.

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Profile of a stream channel at three stages: the Bank-full stage shows the water filling the channel without overflowing, the Flood stage shows the river overfilling the channel and spreading outward with sediments deposited on the top of the river banks, and deposition of natural levee shows the river within the channel due to natural levels forming that raised the stream banks higher.
Figure 11.13: Profile of stream channel at bankfull stage, flood stage, and deposition of natural levee.

A is the flat area of land adjacent to a channel inundated with flood water on a regular basis. flooding is a natural process that adds to floodplains. A typically reaches its greatest velocity when it is close to flooding, known as the . As soon as the flooding overtops its banks and flows onto its , the velocity decreases. that was being carried by the swiftly moving water is deposited at the edge of the channel, forming a low ridge or . In addition, are added to the during this flooding process contributing to fertile .

Zone of Sediment Deposition

Deposition occurs when and come to rest on the bottom of the channel, lake, or ocean due to decrease in and reduction in velocity. While both and occur in the zone of transport such as on point bars and , ultimate where the reaches a lake or ocean. Landforms called deltas form where the enters quiet water composed of the finest such as fine sand, silt, and clay.

Equilibrium and Base Level

Longitudinal profile of a creek in Indiana with altitude along the y-axis and river miles from mouth on the x-axis: it shows steep gradient in its headwaters the farthest away from its mouth and shallower gradients toward its mouth.
Figure 11.14: Example of a longitudinal profile of a stream; Halfway Creek, Indiana.

All three zones are present in the typical of a which plots the elevation of the channel at all points along its course (see figure 11.14). All have a long profile. The long profile shows the from headwater to . All attempt to achieve an energetic balance among , transport, , velocity, discharge, and channel characteristics along the ’s profile. This balance is called equilibrium, a state called .

Another factor influencing equilibrium is , the elevation of the ‘s representing the lowest level to which a can erode. The ultimate is, of course, sea-level. A lake or may also represent for a entering it. The Great Basin of western Utah, Nevada, and parts of some surrounding states contains no outlets to the sea and provides internal base levels for within it. for a entering the ocean changes if sea-level rises or . also changes if a natural or human-made dam is added along a ‘s profile. When is lowered, a will cut down and deepen its channel. When rises, increases as the adjusts attempting to establish a new state of equilibrium. A that has approximately achieved equilibrium is called a .

11.5.5 Fluvial Landforms

landforms are the land features formed on the surface by either or . The -related landforms described here are primarily related to channel types.

Channel Types

Many channels that braid back and forth among each other; between channels are tan sediment deposits.
Figure 11.15: The braided Waimakariri river in New Zealand.
Sinuous tan river running through roughly flat green terrain.
Figure 11.16: Air photo of the meandering river, Río Cauto, Cuba.

channels can be straight, , , or entrenched. The , load, , and location of all influence channel type. are relatively straight, located near the , have steep gradients, low , and narrow V-shaped valleys. Examples of these are located in mountainous areas.

have multiple channels splitting and recombining around numerous mid-channel bars. These are found in floodplains with low gradients in areas with near sources of coarse such as trunk draining mountains or in front of .

have a single channel that curves back and forth like a snake within its where it emerges from its into the zone of transport. are dynamic creating a wide by eroding and extending meander loops side-to-side. The highest velocity water is located on the outside of a meander bend. of the outside of the curve creates a feature called a and the meander extends its loop wider by this .

U-shaped river bend in France with sandy deposition at the inside of the bend labeled Point Bar and erosion on the outside of the bend labeled Cut Bank; there is lush green vegetation around the river and cliffs in the background.
Figure 11.17: Point bar and cut bank on the Cirque de la Madeleine in France.

The of the is the deepest part of the channel. In the straight parts of the channel, the and highest velocity are in the center of the channel. But at the bend of a , the shifts toward the . Opposite the on the inside bend of the channel is the lowest velocity and is an area of called a .

In areas of uplift such as on the Colorado Plateau, that once flowed on the plateau surface have become entrenched or incised as uplift occurred and the cut its down into . Over the past several million years, the Colorado River and its tributaries have incised into the flat lying rocks of the plateau by hundreds, even thousands of feet creating deep canyons including the Grand Canyon in Arizona.

Steep U-shaped canyon; a river with narrow shores fills in the gorge.
Figure 11.18: An entrenched meander on the Colorado River in the eastern entrance to the Grand Canyon.
Panoramic view of an S-shaped meandering river that flows at the base of tall canyons.
Figure 11.19: Panoramic view of incised meanders of the San Juan River at Gooseneck State Park, Utah.
Astronaut-taken photograph of two long branches of Lake Powell, which extends across southeastern Utah and northeastern Arizona. The serpentine surface of the reservoir is highlighted by gray regions of sunglint and follows the incised course of the canyon, surrounded by a tan landscape. The two branches of the lake are connected by a bend to the southwest which is cut off at the bottom of the photo.
Figure 11.20: The Rincon is an abandoned meander loop on the entrenched Colorado River in Lake Powell.
Satellite image of a large flood plain; the main river branches into two on the right-hand side of the photo, then spreads out toward the left into numerous smaller meandering streams; fertile green land covers the wide area of branching streams.
Figure 11.21: Landsat image of Zambezi Flood Plain, Namibia.

Many landforms occur on a associated with a . Meander activity and regular flooding contribute to widening the by eroding adjacent uplands. The channels are confined by natural levees that have been built up over many years of regular flooding. Natural levees can isolate and direct flow from channels on the from immediately reaching the main channel. These isolated streams are called yazoo streams and flow parallel to the main trunk stream until there is an opening in the levee to allow for a belated confluence.

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Video 11.5: How is a levee formed?

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To limit flooding, humans build artificial levees on flood plains. that breaches the levees during flood stage is called and delivers silt and clay onto the . These deposits are rich in nutrients and often make good farm land. When floodwaters crest over human-made levees, the levees quickly erode with potentially catastrophic impacts. Because of the good , farmers regularly return after floods and rebuild year after year.

River with extreme S-shaped curves surrounded by flat green landscape; two curves of the river nearly touch each other.
Figure 11.22: Meander nearing cutoff on the Nowitna River in Alaska.

Through on the outsides of the meanders and on the insides, the channels of move back and forth across their over time. On very broad floodplains with very low gradients, the meander bends can become so extreme that they cut across themselves at a narrow neck (see figure 11.22) called a cutoff. The former channel becomes isolated and forms an lake seen on the right of the figure. Eventually the lake fills in with and becomes a wetland and eventually a . Stream meanders can migrate and form lakes in a relatively short amount of time. Where channels form geographic and political boundaries, this shifting of channels can cause conflicts.

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Video 11.6: Why do rivers curve?

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Satellite image of an alluvial fan in a tan desert landscape; a stream emerges from a canyon and creates a fan-shaped deposit that has rectangular green patches scattered at the edges of the deposit.
Figure 11.23: Alluvial fan in Iraq seen by NASA satellite. A stream emerges from the canyon and creates this cone-shaped deposit.

fans are a depositional landform created where emerge from mountain canyons into a valley. The channel that had been confined by the canyon walls is no longer confined, slows down and spreads out, dropping its of all sizes, forming a in the air of the valley. As distributary channels fill with , the is diverted laterally, and the fan develops into a cone shaped landform with distributaries radiating from the canyon . fans are common in the dry climates of the West where emerge from canyons in the ranges of the .

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Map of central North America showing the main branch of the Mississippi River and the many tributaries that contribute to the river.
Figure 11.24: Location of the Mississippi River drainage basin and Mississippi River delta.

A is formed when a reaches a quieter body of water such as a lake or the ocean and the and is deposited. If wave from the water body is greater than from the , a will not form. The largest and most famous in the United States is the Mississippi River formed where the Mississippi River flows into the Gulf of Mexico. The Mississippi River is the largest in North America, draining 41% of the contiguous United States. Because of the large area, the carries a large amount of . The Mississippi River is a major shipping route and human engineering has ensured that the channel has been artificially straightened and remains fixed within the . The is now 229 km shorter than it was before humans began engineering it. Because of these restraints, the is now focused on one trunk channel and has created a “bird’s foot” pattern. The two NASA images below of the show how the has retreated and land was inundated with water while of was focused at end of the distributaries. These images have changed over a 25 year from 1976 to 2001. These are stark changes illustrating sea-level rise and land from the of peat due to the lack of resupply.

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The of the Mississippi River started about 7500 years ago when postglacial sea level stopped rising. In the past 7000 years, prior to modifications, the Mississippi River formed several sequential lobes. The abandoned each lobe for a more preferred route to the Gulf of Mexico. These lobes were reworked by the ocean waves of the Gulf of Mexico. After each lobe was abandoned by the , isostatic depression and of the caused and the land to sink. 

A lake surrounded by forest-covered mountain slopes.
Figure 11.25: Delta in Quake Lake Montana. Deposition of this delta began in 1959, when the Madison river was dammed by the landslide caused by the 7.5 magnitude earthquake.

A clear example of how deltas form came from an earthquake. During the 1959 Madison Canyon 7.5 earthquake in Montana, a large dammed the Madison River forming Quake Lake still there today. A small that once flowed into the Madison River, now flows into Quake Lake forming a composed of coarse actively eroded from the mountainous upthrown block to the north.

Deltas can be further categorized as wave-dominated or -dominated. Wave-dominated deltas occur where the tides are small and wave energy dominates. An example is the Nile River in the Mediterranean Sea that has the classic shape of the Greek character (Δ) from which the landform is named. A -dominated forms when ocean tides are powerful and influence the shape of the . For example, Ganges-Brahmaputra Delta in the Bay of Bengal (near India and Bangladesh) is the world’s largest and mangrove swamp called the Sundarban. 

Map of the Ganges River leading into a delta; there are also many smaller parallel streams also leading into the delta.
Figure 11.26: Sundarban Delta in Bangladesh, a tide-dominated delta of the Ganges River.

At the Sundarban Delta in Bangladesh, tidal forces create linear intrusions of seawater into the . This also holds the world’s largest mangrove swamp.

Satellite view of a land-sea boundary with a green fan-shaped delta between the edge of tan land and deep blue ocean, widening toward the ocean.
Figure 11.27: Nile Delta showing its classic “delta” shape.
Map of Lake Bonneville in northwestern Utah; the modern Great Salt Lake is outlined in the northern part of Lake Bonneville and is much smaller than Lake Bonneville.
Figure 11.28: Map of Lake Bonneville, showing the outline of the Bonneville shoreline, the highest level of the lake.

Lake Bonneville was a large, that occupied the western half of Utah and parts of eastern Nevada from about 30,000 to 12,000 years ago. The lake filled to a maximum elevation as great as approximately 5100 feet above mean sea level, filling the basins, leaving the mountains exposed, many as islands. The presence of the lake allowed for of both fine grained lake mud and silt and coarse gravels from the mountains. Variations in lake level were controlled by regional and a catastrophic failure of Lake Bonneville’s main outlet, Red Rock Pass. During extended of time in which the lake level remained stable, wave-cut were produced that can be seen today on the flanks of many mountains in the region. Significant deltas formed at the mouths of major canyons in Salt Lake, Cache, and other Utah valleys. The Great Salt Lake is the remnant of Lake Bonneville and cities have built up on these deposits.

Satellite view of tan desert landscape with slopes on the left leading down to a flat white playa labeled Pilot Valley Playa on the right; the slopes are labeled Pilot Range; near the bottom of the image at the base of the slopes is the label Bonneville shoreline; near the top of the image at the base of the slopes are the labels offshore sediments of Lake Bonneville and Provo shoreline; leading from the base of the slopes to the playa is the label multiple unnamed shorelines on alluvial fans on the eastern piedmont of the Pilot Range with another label Stansbury shoreline.
Figure 11.29: Deltaic deposits of Lake Bonneville near Logan, Utah; wave cut terraces can be seen on the mountain slope.

are remnants of older floodplains located above the existing and . Like , form when uplift occurs or drops and erode downward, their meanders widening a new . can also form from extreme flood events associated with retreating . A classic example of multiple are along the Snake in Grand Teton National Park in Wyoming.

Landscape with a winding river in the foreground and steep rocky mountains in the background. Three different levels of flat surfaces are visible in the foreground.
Figure 11.30: Terraces along the Snake River, Wyoming.

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11.6 Groundwater

is an important source of freshwater. It can be found at varying depths in all places under the ground, but is limited by extractable quantity and quality.

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Video 11.7: What is an aquifer?

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11.6.1 Porosity and Permeability

An  is a rock unit that contains extractable ground water. A good must be both porous and permeable. Porosity is the space between grains that can hold water, expressed as the percentage of open space in the total volume of the rock. comes from connectivity of the spaces that allows water to move in the . can occur as primary , as space between sand grains or vesicles in rocks, or secondary as or spaces in rock). and during of reduces (see section 5.3).

A combination of a place to contain water () and the ability to move water () makes a good —a rock unit or that allows extraction of . Well-sorted have higher because there are not smaller particles filling in the spaces between the larger particles. made of clays generally have high , but the are poorly connected, thereby causing low .

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Video 11.8: Porosity and permeability.

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While is an important measure of porous material’s ability to transmit water is more commonly used by geologists to measure how easily a fluid is transmitted. measures both the permeability of the porous material and the properties of the water, or whatever fluid is being transmitted like or gas. Because  also measures the properties of the fluid, such as , it is used by both  geologists and hydrogeologists to describe both the production capability of   and of . High  indicates that fluid transmits rapidly through an 

11.6.2 Aquifers

are rock layers with sufficient and to allow water to be both contained and move within them. For rock or to be considered an , its must be at least partially filled with water and it must be permeable enough to transmit water. Drinking water must also contain potable water. can vary dramatically in scale, from spanning several covering large regions to being a local in a limited area. adequate for water supply are both permeable, porous, and potable.

11.6.3 Groundwater Flow

Cross sectional diagram that shows the subsurface below a vegetated ground surface that slopes downward toward the left; the upper part of the ground is labeled Vadose Zone and the part below that zone is labeled Zone of Saturation. The boundary between the zones is labeled Water Table and there is a small zone just above the Water Table labeled Capillary Fringe. The flow of groundwater is toward the left.
Figure 11.31: Zone of saturation.

When surface water or seeps into the ground, it usually enters the unsaturated zone also called the , or zone of aeration. The is the volume of geologic material between the land surface and the where the spaces are not completely filled with water. Plant roots inhabit the upper and fluid pressure in the is less than atmospheric pressure. Below the is the capillary fringe. Capillary fringe is the usually thin zone below the where the are completely filled with water (), but the fluid pressure is less than atmospheric pressure. The in the capillary fringe are filled because of capillary action, which occurs because of a combination of and . Below the capillary fringe is the zone or phreatic zone, where the are completely and the fluid in the is at or above atmospheric pressure. The interface between the capillary fringe and the zone marks the location of the .

Wells are conduits that extend into the ground with openings to the , to extract from, measure, and sometimes add water to the . Wells are generally the way that geologists and hydrologist measure the depth to from the land surface as well as withdraw water from .

Water is found throughout the spaces in and . The is the area below which the are fully with water. The simplest case of a is when the is unconfined, meaning it does not have a above it. can pressurize by trapping water that is at a higher elevation underneath the , allowing for a higher than the top of the , and sometimes higher than the land surface.

Cross section of aquifers: there are two aquifers with one aquitard between them, surrounded by the bedrock aquiclude. The lower aquifer is labeled Confined aquifer and the upper aquifer is labeled Unconfined aquifer; the boundary at the top of the Unconfined aquifer is labeled Water table and the ground above is labeled Unsaturated zone. The direction of groundwater flow is shown with arrows which flow toward the surface where a stream channel is located; trees at the surface are labeled Transpiration by vegetation.
Figure 11.32: An aquifer cross-section. This diagram shows two aquifers with one aquitard (a confining or impermeable layer) between them, surrounded by the bedrock aquiclude, which is in contact with a gaining stream (typical in humid regions).

A is a low layer above and/or below an that restricts the water from moving in and out of the . include , which are so impermeable that no water travels through them, and , which significantly decrease the speed at which water travels through them. The represents the height that water would rise in a well penetrating the pressurized . Breaches in the pressurized , like or wells, can cause springs or , also known as wells.

The will generally mirror surface topography, though more subdued, because hydrostatic pressure is equal to atmospheric pressure along the surface of the . If the intersects the ground surface the result will be water at the surface in the form of a gaining , , lake, or wetland. The intersects the channel for gaining which then gains water from the . The channels for losing lie below the , thus losing lose water to the . Losing may be seasonal during a dry season or in dry climates where they may normally be dry and carry water only after rain storms. pose a serious danger of  in dry climates.

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Video 11.9: Where is the water table?

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Mentioned in the video is the USGS Groundwater Watch site. 

Using wells, geologists measure the ’s height and the . Graphs of the depth to  over time, are known as hydrographs and show changes in the  over time. Wellwater level is controlled by many factors and can change very frequently, even every minute, seasonally, and over longer  of time.

In 1856, French engineer Henry Darcy developed a to show how through a porous medium is controlled by , pressure, and crosssectional area. To prove this relationshipDarcy experimented with tubes of packed with water running through them. The results of his experiments empirically established measure of and  that is known as Darcy’s law. The relationships described by Darcy’s Law have close similarities to Fourier’s law in the field of heat conduction, Ohm’s law in the field of electrical networks, or Fick’s law in diffusion


Schematic diagram of a horizontal pipe: the pipe is a porous medium and the length of the pipe is labeled L. A cross sectional slice of the pipe is labeled A. The left end of the pipe is labeled a and the right end of the pipe is labeled b; a smaller pipe enters and exits the main pipe with an arrow pointing toward the right labeled Q.
Figure 11.33: Pipe showing apparatus that would demonstrate Darcy’s Law. Δh would be measured across L from a to b.
  • Q = flow (volume/time)
  • K = (length/time)
  • A = cross-sectional area of flow (area)
  • Δh = change in pressure head (pressure difference)
  • L = distance between pressure (h) measurements (length)
  • Δh/L is commonly referred to as the hydraulic

Pumping water from an unconfined  lowers the . Pumping water from a confined lowers the pressure and/or  around the well. In an unconfined , the  is lowered as water is removed from the  near the well producing drawdown and a (see figure 11.34). In a confined , pumping on an reduces the pressure or around the well.

Cross sectional diagram that shows the subsurface around where a water well is located. The shape of the water table around the well is cone-shaped, where groundwater level has the greatest drawdown near the well.
Figure 11.34: Cones of depression.

When one intersects another or a barrier feature like an impermeable mountain block, drawdown is intensified. When a intersects a recharge zone, the is lessened.

11.6.4 Recharge

The  area is where surface water enters an through the process of . areas are generally topographically high locations of an . They are characterized by losing and permeable rock that allows into the . areas mark the beginning of flow paths.

In the  Province,  areas for the unconsolidated  of the valleys are along mountain foothills. In the foothills of Salt Lake Valley, losing contribute water to the gravel-rich deltaic deposits of ancient Lake Bonneville, in some cases feeding wells in the Salt Lake Valley.

An  management practice is to induce through storage and recovery. Geologists and hydrologists can increase the recharge rate into an   using injection wells and  galleries or basins. Injection wells pump water into an  where it can be stored. Injection wells are regulated by state and federal governments to ensure that the injected water is not negatively impacting the quality or supply of the existing in the . Some can store significant quantities of water, allowing water managers to use the like a surface . Water is stored in the during of low water demand and high water supply and later extracted during times of high water demand and low water supply.

Cross sectional diagram that shows the the different ways an aquifer can be recharged: on the left side of the diagram there is a storm cloud releasing precipitation onto the ground surface with some water becoming runoff and some infiltrating and recharging the aquifer; near the center of the diagram there is an artificial recharge well that injects water directly into the aquifer; on the right side of the diagram there is a stream at the surface that naturally recharges the aquifer.
Figure 11.35: Different ways an aquifer can be recharged.

11.6.5 Discharge

areas are where the  or  intersects the land surface.  areas mark the end of  flow paths. These areas are characterized by springs, flowing () wells, gaining , and  in the dry valley basins of the  Province of the western United States.

11.6.6 Groundwater Mining and Subsidence

Like other on our planet, the quantity of fresh and potable water is finite. The only natural source of water on land is from the sky in the form of . In many places,  is being extracted faster than it is being replenished. When  is extracted faster than it is recharged,  levels and potentiometric surfaces declineand  areas diminish or dry up completely. Regional pumping-induced decline is known as or overdraft. is a serious situation and can lead to dry wells, reduced spring and flow, and . Groundwater  is happening is places where more water is extracted by pumping than is being replenished by , and the  is continually lowered. In these situations, must be viewed as a body and in its depletion, the possibility of producing ghost towns.

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Man standing next to pole with signs showing approximate altitude of land surface in 1925 (highest sign on pole), 1955 (middle sign on pole), and 1977 (at ground level).
Figure 11.36: Evidence of land subsidence from pumping of groundwater shown by dates on a pole.

In many places, water actually helps hold up an ’s skeleton by the water pressure exerted on the grains in an . This pressure is called pressure and comes from the weight of overlying water. If pressure decreases because of , the  can compact, causing the surface of the ground to sink. Areas especially susceptible to this effect are  made of unconsolidated . Unconsolidated  with multiple layers of clay and other fine-grained material are at higher risk because when water is drained, clay compacts considerably. 

from has been documented in southwestern Utah, notably Cedar Valley, Iron County, Utah. levels have declined more than 100 feet in certain parts of Cedar Valley, causing earth fissures and measurable amounts of land .

This photo shows documentation of from pumping of for irrigation in the Central Valley in California. The pole shows from pumping over a of time.

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11.7 Water Contamination and Remediation

Water can be contaminated by natural features like -rich geologic  and by human activities such as agriculture, industrial operations, landfills, animal operations, and sewage treatment processes, among many other thingsAs water runs over the land or  into the ground, it dissolves material left behind by these potential contaminant sources. There are three major groups of contamination: organic and inorganic chemicals and biological agents. Small  that cloud water, causing turbidity, is also an issue with some wells, but it is not considered contamination. The risks and type of  for a contaminant depends on the type of chemicals present. 

Contamination occurs as pointsource and nonpointsource pollution.  pollution can be attributed to a single, definable source, while pollution is from multiple dispersed sources. include waste disposal sites, storage tanks, sewage treatment plants, and chemical spills. Nonpoint sources are dispersed and indiscreet, where the whole of the contribution of pollutants is harmful, but the individual components do not have harmful concentrations of pollutants. A good example of nonpoint pollution is residential areas, where lawn fertilizer on one person’s yard may not contribute much pollution to the , but the combined effect of many residents using fertilizer can lead to significant nonpoint pollution. Other nonpoint sources include nutrients (nitrate and ), herbicides, pesticides contributed by farming, nitrate contributed by animal operations, and nitrate contributed by septic systems.

Organic chemicals are common pollutants. They consist of strands and rings of carbon atoms, usually connected by covalent . Other types of atoms, like chlorine, and molecules, like hydroxide (OH), are attached to the strands and rings. The number and arrangement of atoms will decide how the chemical behaves in the environment, its danger to humans or ecosystems, and where the chemical ends up in the environment. The different arrangements of carbon allow for tens of thousands of organic chemicals, many of which have never been studied for negative effects on human health or the environment. Common organic pollutants are herbicides and pesticides, pharmaceuticals, fuel, and industrial solvents and cleansers.

Organic chemicals include surfactants such as cleaning agents and synthetic hormones associated with pharmaceuticals, which can act as endocrine disruptors. Endocrine disruptors mimic hormones, and can cause long-term effects in developing sexual reproduction systems in developing animals. Only very small quantities of endocrine disruptors are needed to cause significant changes in animal populations.

An example of organic chemical contamination is the Love Canal, Niagara Falls, New York. From 1942 to 1952, the Hooker Chemical Company disposed of over 21,337 mt (21,000 t) of chemical waste, including chlorinated hydrocarbons, into a canal and covered it with a thin layer of clay. Chlorinated hydrocarbons are a large group of organic chemicals that have chlorine functional groups, most of which are toxic and carcinogenic to humans. The company sold the land to the New York School Board, who developed it into a neighborhood. After residents began to suffer from serious health ailments and pools of oily fluid started rising into residents’ basements, the neighborhood had to be evacuated. This site became a U.S. Environmental Protection Agency , a site with federal funding and oversight to ensure its cleanup.

Inorganic chemicals are another set of chemical pollutants. They can contain carbon atoms, but not in long strands or links. Inorganic contaminants include chloride, arsenic, and nitrate (NO3). Nutrients can be from geologic material, like phosphorous-rich rock, but are most often sourced from fertilizer and animal and human waste. Untreated sewage and agricultural contain concentrates of nitrogen and phosphorus which are essential for the growth of microorganisms. Nutrients like nitrate and in surface water can promote growth of microbes, like blue-green algae (cyanobacteria), which in turn use oxygen and create toxins (microcystins and anatoxins) in lakes. This process is known as eutrophication.

Metals are common inorganic contaminants. Lead, mercury, and arsenic are some of the more problematic inorganic contaminants. Bangladesh has a well documented case of arsenic contamination from natural geologic material dissolving into the . Acid  can also cause significant inorganic contamination (see chapter 16).

Salt, typically sodium chloride, is a common inorganic contaminant. It can be introduced into from natural sources, such as deposits like the Arapien Shale of Utah, or from sources like the salts applied to roads in the winter to keep ice from forming. Salt contamination can also occur near ocean coasts from saltwater intruding into the cones of depression around fresh  pumping, inducing the encroachment of saltwater into the freshwater body.

Biological agents are another common  contaminant which includes harmful bacteria and viruses. A common bacteria contaminant is Escherichia coli (E. coli). Generally, harmful bacteria are not present in  unless the  source is closely connected with a contaminated surface source, such as a septic . , landforms created from  , is especially susceptible to this form of contamination, because water moves relatively quickly through the conduits of  Bacteria can also be used for .

View USGS tables on contaminants found in groundwater.

is the act of cleaning contamination. Hydrologists use three types of biological, chemical, and physical. Biological uses specific of bacteria to break down a contaminant into safer chemicals. This type of is usually used on organic chemicals, but also works on reducing or oxidizing inorganic chemicals like nitrate. Phytoremediation is a type of bioremediation that uses plants to absorb the chemicals over time.

Chemical uses chemicals to remove the contaminant or make it less harmful. One example is to use a reactive barrier, a permeable wall in the ground or at a point that chemically reacts with contaminants in the water. Reactive barriers made of can increase the pH of , making the water less acidic and more basic, which removes contaminants by into solid form.

Physical consists of removing the contaminated water and either treating it with filtration, called pumpandtreat, or disposing of it. All of these options are technically complex, expensive, and difficult, with physical typically being the most costly.

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11.8 Karst

River flowing across landscape of flat land with steep rock towers rising from the land.
Figure 11.37: Steep karst towers in China left as remnants as limestone is dissolved away by acidic rain and groundwater.

refers to landscapes and hydrologic features created by the dissolving of . can be found anywhere there is  and other soluble subterranean substances like salt deposits. Dissolving of limestone creates features like sinkholes, caverns, disappearing , and towers. 

Light tan landscape with numerous bowl-shaped sinkholes.
Figure 11.38: Sinkholes of the McCauley Sink in Northern Arizona, produced by collapse of Kaibab Limestone into caverns caused by solution of underlying salt deposits.

Dissolving of underlying salt deposits has caused sinkholes to form in the Kaibab Limestone on the Colorado Plateau in Arizona.

Dirt-lined sinkhole in front of a gray house; the sinkhole is cordoned off with caution tape.
Figure 11.39: This sinkhole from collapse of surface into a underground cavern appeared in the front yard of this home in Florida.

Collapse of the surface into an underground cavern caused this sinkhole in the front yard of a home in Florida. 

CO2 in the  dissolves readily in the water droplets that form clouds from which  comes in the form of rain and snow. This  is slightly acidic with . Karst forms when carbonic acid dissolves  (calcium ) in 

H2O + CO2 = H2CO3

Water + Carbon Dioxide Gas equals Carbonic Acid in Water

CaCO3 + H2CO3 = Ca2++ 2HCO3 -1

Solid Calcite + Carbonic Acid in Water Dissolved equals Calcium Ion + Dissolved Bicarbonate Ion

White and brown natural steps with steam rising near the back; the brown steps have a coating of liquid and organic material while the white steps are dry and chalky in appearance. There are a few dead tree trunks in the springs.
Figure 11.40: Mammoth hot springs, Yellowstone National Park.

After the slightly acidic water dissolves the , changes in or gas content in the water can cause the water to redeposit the in a different place as (), often deposited by a or in a cave. Speleothems are secondary deposits, typically made of , deposited in a cave. speleothems form by water dripping through cracks and openings in caves and evaporating, leaving behind the deposits. Speleothems commonly occur in the form of stalactites, when extending from the ceiling, and stalagmites, when standing up from the floor.

Numerous cave formations hanging from the top and protruding from the base of a cave. Smooth, bulbous formations protruding from the base are labeled Flowstone and spires that rise from the base are labeled Stalagmites. Spires that hang from the ceiling are labeled Stalactites, small tubes hanging are labeled Straws, and ribbon-like formations hanging from the ceiling are labeled Drapery. One formation stretches from the ceiling of the cave to the base of the cave, labeled Column.
Figure 11.41: Varieties of speleothems.
A stream disappears into gravel at the foreground of the photo.
Figure 11.42: This stream disappears into a subterranean cavern system to re-emerge a few hundred yards downstream.

Surface water enters the through sinkholes, losing , and disappearing . Changes in can cause running over to the and sink into the ground. As the water continues to its way through the , it can leave behind intricate networks of caves and narrow passages. Often will follow and expand in the . Water exits the as springs and rises. In mountainous , can extend all the way through the vertical profile of the mountain, with caverns dropping thousands of feet.

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Water is essential for all living things. It continuously cycles through the , over land, and through the ground. In much of the United States and other countries, water is managed through a of regional laws and regulations and distributed on paper in a collectively known as “water rights”. Surface water follows a , which is separate from other areas by its divides (highest ridges). exists in the within rocks and . It moves predominantly due to pressure and gravitational gradients through the rock. Human and natural causes can make water unsuitable for consumption. There are different ways to deal with this contamination. is when is by water, forming caves and sinkholes.

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URLs Linked Within This Chapter

NPR story on Snake Valley: https://www.npr.org/2007/06/12/10953190/las-vegas-water-battle-crops-vs-craps

SNWA History: https://www.snwa.com/about/mission/index.html#:~:text=In%201991%2C%20seven%20local%20water,Big%20Bend%20Water%20District

Dean Baker Story: The Consequences: Transporting Snake Valley water to satisfy a thirsty Las Vegas. [Video: 25:24] https://www.youtube.com/watch?v=eCZ8KLrmUXo

NASA images: https://earthobservatory.nasa.gov/images/8103/mississippi-river-delta

USGS Groundwater Watch: https://groundwaterwatch.usgs.gov/default.asp

USGS tables on contaminants found in groundwater: https://www.usgs.gov/special-topics/water-science-school/science/contamination-groundwater

Text References

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  2. Charlton, R., 2007, Fundamentals of fluvial geomorphology: Taylor & Francis.
  3. Cirrus Ecological Solutions, 2009, Jordan River TMDL: Utah State Division of Water Quality.
  4. Earle, S., 2015, Physical geology OER textbook: BC Campus OpenEd.
  5. EPA, 2009, Water on Tap-What You Need to Know: U.S. Environmental Protection Agency.
  6. Fagan, B., 2012, Elixir: A history of water and humankind: Bloomsbury Press.
  7. Fairbridge, R.W., 1968, Yazoo rivers or streams, in Geomorphology: Springer Berlin Heidelberg Encyclopedia of Earth Science, p. 1238–1239.
  8. Freeze, A.R., and Cherry, J.A., 1979, Groundwater: Prentice Hall.
  9. Galloway, D., Jones, D.R., and Ingebritsen, S.E., 1999, Land subsidence in the United States: U.S. Geological Survey Circular 1182.
  10. Galloway, W.E., Whiteaker, T.L., and Ganey-Curry, P., 2011, History of Cenozoic North American drainage basin evolution, sediment yield, and accumulation in the Gulf of Mexico basin: Geosphere, v. 7, no. 4, p. 938–973.
  11. Gilbert, G.K., 1890, Lake Bonneville: United States Geological Survey, 438 p.
  12. Gleick, P.H., 1993, Water in Crisis: A Guide to the World’s Fresh Water Resources: Oxford University Press.
  13. Hadley, G., 1735, Concerning the cause of the general trade-winds: By Geo. Hadley, Esq; FRS: Philosophical Transactions, v. 39, no. 436–444, p. 58–62.
  14. Halvorson, S.F., and James Steenburgh, W., 1999, Climatology of lake-effect snowstorms of the Great Salt Lake: University of Utah.
  15. Heath, R.C., 1983, Basic ground-water hydrology: U.S. Geological Survey Water-Supply Paper 2220, 91 p.
  16. Hobbs, W.H., and Fisk, H.N., 1947, Geological Investigation of the Alluvial Valley of the Lower Mississippi River: JSTOR.
  17. Knudsen, T., Inkenbrandt, P., Lund, W., Lowe, M., and Bowman, S., 2014, Investigation of land subsidence and earth fissures in Cedar Valley, Iron County, Utah: Utah Geological Survey Special Study 150.
  18. Lorenz, E.N., 1955, Available potential energy and the maintenance of the general circulation: Tell’Us, v. 7, no. 2, p. 157–167.
  19. Marston, R.A., Mills, J.D., Wrazien, D.R., Bassett, B., and Splinter, D.K., 2005, Effects of Jackson lake dam on the Snake River and its floodplain, Grand Teton National Park, Wyoming, USA: Geomorphology, v. 71, no. 1–2, p. 79–98.
  20. Maupin, M.A., Kenny, J.F., Hutson, S.S., Lovelace, J.K., Barber, N.L., and Linsey, K.S., 2014, Estimated use of water in the United States in 2010: US Geological Survey.
  21. Myers, W.B., and Hamilton, W., 1964, The Hebgen Lake, Montana, earthquake of August 17, 1959: U.S. Geol. Surv. Prof. Pap., v. 435, p. 51.
  22. Oviatt, C.G., 2015, Chronology of Lake Bonneville, 30,000 to 10,000 yr B.P: Quat. Sci. Rev., v. 110, p. 166–171.
  23. Powell, J.W., 1879, Report on the lands of the arid region of the United States with a more detailed account of the land of Utah with maps: Monograph.
  24. Reed, J.C., Love, D., and Pierce, K., 2003, Creation of the Teton landscape: a geologic chronicle of Jackson Hole and the Teton Range: pubs.er.usgs.gov.
  25. Reese, R.S., 2014, Review of Aquifer Storage and Recovery in the Floridan Aquifer System of Southern Florida.
  26. Schele, L., Miller, M.E., Kerr, J., Coe, M.D., and Sano, E.J., 1992, The Blood of Kings: Dynasty and Ritual in Maya Art: George Braziller Inc.
  27. Seaber, P.R., Kapinos, F.P., and Knapp, G.L., 1987, Hydrologic unit maps.
  28. Solomon, S., 2011, Water: The Epic Struggle for Wealth, Power, and Civilization: Harper Perennial.
  29. Törnqvist, T.E., Wallace, D.J., Storms, J.E.A., Wallinga, J., Van Dam, R.L., Blaauw, M., Derksen, M.S., Klerks, C.J.W., Meijneken, C., and Snijders, E.M.A., 2008, Mississippi Delta subsidence primarily caused by compaction of Holocene strata: Nat. Geosci., v. 1, no. 3, p. 173–176.
  30. Turner, R.E., and Rabalais, N.N., 1991, Changes in Mississippi River water quality this century: Bioscience, v. 41, no. 3, p. 140–147.
  31. United States Geological Survey, 1967, The Amazon: Measuring a Mighty River: United States Geological Survey O-245-247.
  32. U.S. Environmental Protection Agency, 2014, Cyanobacteria/Cyanotoxins.
  33. U.S. Geological Survey, 2012, Snowmelt – The Water Cycle, from USGS Water-Science School.
  34. Utah/Nevada Draft Snake Valley Agreement, 2013.

Figure References

Figure 11.1: Example of a Roman aqueduct in Segovia, Spain. Bernard Gagnon. 2009. CC BY-SA 3.0. https://en.wikipedia.org/wiki/File:Aqueduct_of_Segovia_08.jpg

Figure 11.2: Chac mask in Mexico. Bernard DUPONT. 1995. CC BY-SA 2.0. https://commons.wikimedia.org/wiki/File:Chac_Mask_(21784027699).jpg

Figure 11.3: The water cycle. John Evans and Howard Periman, USGS. 2013. Public domain. https://commons.wikimedia.org/wiki/File:Watercyclesummary.jpg

Figure 11.4: Map view of a drainage basin with main trunk streams and many tributaries with drainage divide in dashed red line. Zimbres. 2005. CC BY-SA 2.5. https://commons.wikimedia.org/wiki/File:Hydrographic_basin.svg

Figure 11.5: Oblique view of the drainage basin and divide of the Latorita River, Romania. Asybaris01. 2011. Public domain. https://commons.wikimedia.org/wiki/File:EN_Bazinul_hidrografic_al_Raului_Latorita,_Romania.jpg

Figure 11.6: Major drainage basins color coded to match the related ocean. Citynoise. 2007. Public domain. https://commons.wikimedia.org/wiki/File:Ocean_drainage.png

Figure 11.7: Agricultural water use in the United States by state. USGS. 2018. Public domain. https://www.usgs.gov/media/images/map-us-state-showing-total-water-withdrawals-2015

Figure 11.8: Trends in water use by source. USGS. 2018. Public domain. https://www.usgs.gov/media/images/trends-population-and-freshwater-withdrawals-source-1950-2015-0

Figure 11.9: Distribution of precipitation in the United States. United States Department of the Interior. 2006. Public domain. https://commons.wikimedia.org/wiki/File:Average_precipitation_in_the_lower_48_states_of_the_USA.png

Figure 11.10: Thalweg of a river. In a river bend, the fastest moving water is on the outside of the bend, near the cutbank. Steven Earle. 2021. CC BY. Figure 8.1.1 from https://openeducationalberta.ca/practicalgeology/chapter/8-1-stream-erosion-and-deposition/#fig8.1.1

Figure 11.11: Various stream drainage patterns. Kindred Grey. 2022. CC BY-SA 3.0. Includes Rectangular by Zimbres, 2006 (CC BY-SA 2.5, https://commons.wikimedia.org/wiki/File:Rectangular.png). Dendritic by Zimbres, 2006 (CC BY-SA 2.5, https://en.wikipedia.org/wiki/File:Dendritic.png). Trellis drainage pattern by Tshf aee, 2007 (CC BY-SA 3.0, https://en.wikipedia.org/wiki/File:Trellis_drainage_pattern.JPG). Radial by Zimbres, 2006 (CC BY-SA 2.5, https://commons.wikimedia.org/wiki/File:Radial.png). Irregular drainage pattern by Tshf aee, 2007 (CC BY-SA 3.0, https://en.wikipedia.org/wiki/File:Irregular_drainage_pattern.JPG).

Figure 11.12: A stream carries dissolved load, suspended load, and bedload. PSUEnviroDan. 2008. Public domain. https://en.wikipedia.org/wiki/File:Stream_Load.gif

Figure 11.13: Profile of stream channel at bankfull stage, flood stage, and deposition of natural levee. Steven Earle. 2021. CC BY. Figure 8.1.4 from https://openeducationalberta.ca/practicalgeology/chapter/8-1-stream-erosion-and-deposition/#retfig8.1.3

Figure 11.14: Example of a longitudinal profile of a stream; Halfway Creek, Indiana. USGS. 2008. Public domain. https://commons.wikimedia.org/wiki/File:HalfwayCreek_fig02.jpg

Figure 11.15: The braided Waimakariri river in New Zealand. Greg O’Beirne. 2007. CC BY 2.5. https://www.wikiwand.com/simple/Braided_river#Media/File:Waimakariri01_gobeirne.jpg

Figure 11.16: Air photo of the meandering river, Río Cauto, Cuba. Not home~commonswiki. 2007. Public domain. https://commons.wikimedia.org/wiki/File:Rio-cauto-cuba.JPG

Figure 11.17: Point bar and cut bank on the Cirque de la Madeleine in France. Jean-Christophe BENOIST. 2007. CC BY 2.5. https://www.wikiwand.com/en/Bar_(river_morphology)#Media/File:CirqueMadeleine.jpg

Figure 11.18: An entrenched meander on the Colorado River in the eastern entrance to the Grand Canyon. Paul Hermans. 2012. CC BY-SA 3.0. https://commons.wikimedia.org/wiki/File:Horseshoe_Bend_TC_27-09-2012_15-34-14.jpg

Figure 11.19: Panoramic view of incised meanders of the San Juan River at Gooseneck State Park, Utah. Michael Rissi. 2006. CC BY-SA 3.0. https://commons.wikimedia.org/wiki/File:GooseNeckStateParkPanorama.jpg

Figure 11.20: The Rincon is an abandoned meander loop on the entrenched Colorado River in Lake Powell. NASA’s Earth Observatory. 2012. CC BY 2.0. https://commons.wikimedia.org/wiki/File:Lake_Powell_and_The_Rincon,_Utah_-_NASA_Earth_Observatory.jpg

Figure 11.21: Landsat image of Zambezi Flood Plain, Namibia. Jesse Allen and Robert Simmon
via NASA. 2010. Public domain. https://commons.wikimedia.org/wiki/File:Zambezi_Flood_Plain,_Namibia_(EO-1).jpg

Figure 11.22: Meander nearing cutoff on the Nowitna River in Alaska. Oliver Kurmis. 2002. CC BY-SA 2.0 DE. https://www.wikiwand.com/en/Oxbow_lake#Media/File:Nowitna_river.jpg

Figure 11.23: Alluvial fan in Iraq seen by NASA satellite. NASA. 2004. Public domain. https://commons.wikimedia.org/wiki/File:Alluvial_fan_in_Iran.jpg

Figure 11.24: Location of the Mississippi River drainage basin and Mississippi River delta. Shannon1. 2016. CC BY-SA 4.0. https://commons.wikimedia.org/wiki/File:Mississippiriver-new-01.png

Figure 11.25: Delta in Quake Lake Montana. Staplegunther. 2007. CC BY-SA 3.0. https://commons.wikimedia.org/wiki/File:Quakelakemontana.jpg

Figure 11.26: Sundarban Delta in Bangladesh, a tide-dominated delta of the Ganges River. NordNordWest. 2015. CC BY-SA 3.0 DE. https://commons.wikimedia.org/wiki/File:Bangladesh_adm_location_map.svg

Figure 11.27: Nile Delta showing its classic “delta” shape. NASA. 2018. Public domain. https://www.earthdata.nasa.gov/worldview/worldview-image-archive/the-nile-delta-from-space

Figure 11.28: Map of Lake Bonneville, showing the outline of the Bonneville shoreline, the highest level of the lake. Staplini. 2019. CC BY-SA 4.0. https://commons.wikimedia.org/wiki/File:Map_of_Lake_Bonneville.jpg

Figure 11.29: Deltaic deposits of Lake Bonneville near Logan, Utah; wave cut terraces can be seen on the mountain slope. Staplini. 2019. CC BY-SA 4.0. https://commons.wikimedia.org/wiki/File:Image_of_Lake_Bonneville_shorelines.png

Figure 11.30: Terraces along the Snake River, Wyoming. Fredlyfish4. 2008. CC BY-SA 3.0. https://commons.wikimedia.org/wiki/File:Snake_River_Overlook.JPG

Figure 11.31: Zone of saturation. USGS. 2011. Public domain. https://commons.wikimedia.org/wiki/File:Vadose_zone.gif

Figure 11.32: An aquifer cross-section. Hans Hillewaert. 2007. CC BY-SA 3.0. https://commons.wikimedia.org/wiki/File:Aquifer_en.svg

Figure 11.33: Pipe showing apparatus that would demonstrate Darcy’s Law. Vectorised by Sushant savla from the work by Peter Kapitola. 2018. CC BY-SA 2.5. https://en.m.wikipedia.org/wiki/File:Darcy%27s_Law.svg

Figure 11.34: Cones of depression. USGS. 2018. Public domain. https://www.usgs.gov/media/images/cone-depression-pumping-a-well-can-cause-water-level-lowering

Figure 11.35: Different ways an aquifer can be recharged. USGS. Unknown date. Public domain. https://www.usgs.gov/media/images/groundwater-can-be-recharged-naturally-and-artificially

Figure 11.36: Evidence of land subsidence from pumping of groundwater shown by dates on a pole. Dr. Joseph F. Poland via USGS. 1977. Public domain. https://www.usgs.gov/media/images/location-maximum-land-subsidence-us-levels-1925-and-1977

Figure 11.37: Steep karst towers in China left as remnants as limestone is dissolved away by acidic rain and groundwater. chensiyuan. 2011. CC BY-SA 4.0. https://commons.wikimedia.org/wiki/File:1_li_jiang_guilin_yangshuo_2011.jpg

Figure 11.38: Sinkholes of the McCauley Sink in Northern Arizona, produced by collapse of Kaibab Limestone into caverns caused by solution of underlying salt deposits. Google Earth. Image retrieved 2022 by Kindred Grey. Public domain.

Figure 11.39: This sinkhole from collapse of surface into a underground cavern appeared in the front yard of this home in Florida. Ann Tihansky via USGS. 2010. Public domain. https://www.usgs.gov/media/images/sinkholes-west-central-florida-freeze-event-2010-2

Figure 11.40: Mammoth hot springs, Yellowstone National Park. Brocken Inaglory. 2008. CC BY-SA 3.0. https://en.wikipedia.org/wiki/File:Dead_trees_at_Mammoth_Hot_Springs.jpg

Figure 11.41: Varieties of speleothems. Dave Bunnell / Under Earth Images. 2006. CC BY-SA 2.5. https://commons.wikimedia.org/wiki/File:Labeled_speleothems.jpg

Figure 11.42: This stream disappears into a subterranean cavern system to re-emerge a few hundred yards downstream. Martyn Gorman. 2007. CC BY-SA 2.0. https://www.geograph.org.uk/photo/471804



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