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This teaching unit is an overview of various issues related to the development of the Albuquerque metropolitan region and the relationship of this development with the Rio Grande River. The unit will examine the river as it is today and how it has changed over time. It will consider the origins of the Rio Grande, current uses of the river, and changes that have characterized the river’s form and processes in recent times. The unit will examine the effects that various control techniques have had on the river and the resulting benefits and problems that have occurred due these control efforts. The information described within this curriculum unit will be used to develop lessons that will be used as part of a high school geology curriculum.

The objectives of the unit are:
-Develop student awareness of issues surrounding the Rio Grande and its management.
-Foster critical thinking and problem-solving skills with this developing awareness.
-Integrate related fields of science such as the life sciences, environmental sciences, anthropology and archaeology to the earth science material being covered in the      class.
-Promote a multifaceted approach to teaching science through the use of debate, writing, and hands-on activities.
-Motivate potentially at-risk students by using material and resources that are more relevant and accessible to them and their daily lives.

Surface Water Hydrology and River Morphology

The Rio Grande River is the second longest river in North America, totaling more than 1,800 miles in length. It is second only in length to the Mississippi/Missouri River of the Central U.S.¹ It stretches from the southern Colorado Rocky mountains to the Gulf of Mexico, and is the predominant drainage feature in the state of New Mexico. The river enters the state north of the Rio Grande gorge and flows south through a series of alluvium-filled basins, or troughs, that have been produced by rifting processes over time. The subsequent erosion of the rift alluvium by the river and its tributaries has produced various landforms in and surrounding this basin.² The resulting landforms are often referred to as the Rio Grande Valley. This process of development and deposition in the Rio Grande rift through New Mexico has been occurring for millions of years. The river currently flows through numerous villages, towns and cities of the state, including the city of Albuquerque, and is a major supplier of surface and ground water used residentially, commercially and agriculturally in these areas.

Several major drainages feed into the Rio Grande. North of Albuquerque, these include the Chama and Jemez Rivers. South of the city, they include the Rio San Jose and the Rio Puerco. The combination of these sources has produced a hydrologic resource allowing for more than 2,000,000 acre-feet of water to be withdrawn per year from the Rio Grande basin in New Mexico for a total discharge area of 32,207 square miles.³ Typically the river reaches its highest discharges in the months from April through June, with its peak levels in May. In general, this pattern reflects the annual natural flows of water due to seasonal snowmelt/runoff and summer monsoon precipitation. Natural flows also show a great deal of variation from year to year. This variation is due to periods of drought and other climatic variabilities.

The river known to many Albuquerque inhabitants of today is much different than the river that would have been found in the region hundreds to thousands of years ago. Prior to measurable human habitation along the Rio Grande river and the resulting influence of humans, the Rio Grande could have been described as a "perennially flowing, aggrading river with a shifting sand substrate."⁴ The river’s pattern of flow through the state and through the region at this time was braided and slightly sinuous, depositing a great amount of sediment across the river’s floodplain. Within the valley, the river would have freely migrated and meandered, creating oxbows, side streams, wetland and marsh areas. In fact, evidence of this movement about the valley can be seen in various areas of the city. The Rio Grande’s past floodplain within Albuquerque extends a distance of 10 miles, from as far west as Nine Mile Hill eastward to the University of New Mexico area.⁵

Despite the ability of the river to move about and migrate in the Rio Grande valley, it has experienced periods of stability and equilibrium. During these periods, riparian ecosystems would have had a chance to become established on riverbanks and islands. During periods of instability, however, deposition of sediments and erosion would allow new locations for riparian vegetation to start.⁶ Thus, a picture of a changing Albuquerque and a changing Rio Grande river can be developed. As human influence on the river has increased though, these patterns of change have diminished or stopped completely. The river has within the last hundred years gone from braided and sinuous to flowing in a single channel.

History of the Rio Grande River

The Rio Grande River flows along the Rio Grande valley, but did not actually carve out the depression it follows, except in a minor way.⁷ The river’s course has been determined by the underlying geological features that characterize the rift valley that divides New Mexico geographically into east and west halves. Thus to understand the origin of the river, an understanding of the past geologic evolution of the state is necessary.

Albuquerque and many of the more populated regions of the state lie along the Rio Grande Rift, an area which sits above a segment of the earth’s crust that is slowly being pulled apart and stretched. Unlike typical valleys, the river did not create the valley it flows through. The valley has been forming by way of geological tension processes for hundreds of millions of years. The rift is an area of slowly subsiding rock and sediments that are bordered on either side by uplifting blocks of rock sliding along fault zones. This has resulted in what has been called the "Rio Grande Trough".⁸ The Sandia mountains along the east side of Albuquerque represent one of these uplifting blocks and fault zones. The Rio Grande river itself flows through the lowest area of the trough and has played a major role in slowly filling the valley with soils and sediments. The thickness of these sediment deposits has been estimated to be about 20,000 feet thick. In other words, the same rocks found at the surface of the Sandias can be found roughly 5 miles below the surface of the Albuquerque valley.⁹

The process of filling the rift valley has been occurring for millions of years. As the Rio Grande flows, it carries a considerable amount of mud, sand and gravel. This material, referred to as alluvium, is deposited along its course. Over great lengths of time, a considerable amount of this alluvium is deposited by the river, and it slowly begins filling up the valley that is being formed by the rifting process. In addition, as this deposition happens, some of the water that has carried the sediment is buried underground. This buried water fills in the loose spaces of the alluvial deposits and is the primary source of Albuquerque’s water needs, or its aquifer.

The Middle Rio Grande basin is one of the oldest areas of habitation in the United States. It is also one of the oldest areas of agriculture use. Farming has been carried on in the area for centuries, dating back to the basket-maker cultures of the pre-Pueblo Indians over one thousand years ago, followed by more modern Pueblo groups, and the first Spanish colonists of the 1500’s. Most recently, extensive farming practices have been carried out as new groups began to settle the area in the last half of the 1800’s. The demands on the river for irrigation purposes have grown along this time line. Irrigation of about 20,000 acres was sufficient to support native populations, but this demand grew to more than 125,000 acres by 1880. Use of water from the Rio Grande resulted in a serious deterioration and aggradation of the river to the point that only 40,000 acres of farmland could be irrigated by 1925. This was a result of irrigation upstream from the basin, depletion of downstream riverflows, high sedimentation rates caused by rising riverbeds (aggradation), unstable riverflows, floods, water-logged lands, and urbanization.¹⁰

Since 1925, the State of New Mexico along with the U.S. Department of the Interior has undertaken a program of river development and maintenance that has significantly changed the Rio Grande river in its appearance and behavior. With the formation of the Middle Rio Grande Conservancy District in that year, projects were begun to increase the efficient use of the river. Aspects of this program included the use of dams, El Vado and Caballo, diversion channels, levees, and "jetty jacks" in an effort to control the flow rate of the river and to minimize its impact on the numerous population centers located on and around the river. These facilities aided irrigation but did little to ease water shortages, floods, high water tables and siltation of ditches.¹¹

Because of problems in aggradation and degradation of the river, a joint effort between the Army Corps of Engineers and the Bureau of Reclamation was initiated. As stated in its Environmental Impact Statement from 1976, the Bureau of Reclamation’s purpose in this program has been to (1) more effectively meet New Mexico’s water obligation without curtailment of water use in New Mexico by providing efficient transport of water through the state; (2) conserve both surface and ground water; (3) reduce the rate of aggradation of the Rio Grande floodway; and (4) provide effective flood control. Projects from this association included the construction of Cochiti Dam, a system of flood-control reservoirs on the river and its tributaries, and a rehabilitation of irrigation systems in the district.¹² In addition to limiting the effects of flooding, reservoirs and other river storage and flood control structures have limited some of the effects of climatic variability. Thus, this has insured a more consistent flow of water from year to year to those dependent on the Rio Grande for agricultural, business and residential water needs in this part of the state.

Historically, the Albuquerque area has suffered from major flooding both along the Rio Grande and in the nearby Sandia canyons. Severe floods had occurred in Albuquerque and its surrounding vicinity on a fairly regular cycle, with events taking place in 1874, 1884, 1891, 1903, 1909, 1912, 1920, 1937, and 1940. In the 1874 flood, it was estimated that 24 square miles of water filled the area between Bernalillo and Albuquerque for over 3 months. This was due to what was approximated as an all-time record river flow of more than 100,000 cubic feet of water per second.¹³ During this and other occasions, the Albuquerque Old Town area has experienced dramatic flooding events. The area, which is relatively higher than its local neighborhood, has become an island several times as the water rose in the lower surrounding areas. In fact, this is the reason that the Old Town area is built in this particular location.

As the population of the middle Rio Grande valley increased in the late 1800’s and 1900’s, the demand for water increased as well. The result of this increased demand was to raise the river channel bed and the damaging effects of the river. Because more water was being removed from the river, its sediment carrying capacity was decreased. This in turn brought about the process of silting and clogging of the river channel. Water tables in the areas surrounding the river rose, and farms became waterlogged. Resulting loss of farmland and the increase in swampland led to an all-out effort by city, state and federal governments to control the Rio Grande’s flow. As Kelley states, "the battle was begun to confine the river".

Early attempts to prevent flooding included increasing the height and strength of existing natural levees and the building of parallel storm channels, which also provided drainage for surrounding wetlands and marshes. These areas are now being utilized as working agricultural areas. Flood-control concrete embankments along the eastside of the city were built to capture runoff and divert it to the Rio Grande. The end result of these measures has been the construction of a system that can withstand "100 year floods" as designated by the U.S. Geological Survey.¹⁴

In addition, other methods utilized locally to prevent and limit the effects of flooding have included the construction of a series of drainage ditches, diversion channels, and concrete arroyos, along with the drilling of numerous industrial and municipal wells. The result of this, with accompanying dry periods, has been to lower Albuquerque’s water table. With this drop in the water table, reclamation projects began and the Albuquerque population has now occupied once previous swampland areas of the city’s yazoo or lowlands.¹⁵

In all, the changes that have been instituted along the river have contributed to a controlled and restricted waterway. As such, with these changes over the last 50 years, the Rio Grande river can no longer be truly considered a "naturally flowing river".¹⁶ The elimination of flooding and the restriction of water flow has also led to serious consequences in other areas. These areas are only recently becoming recognized, and questions of past practices of river management have now come under great scrutiny.

Attracting critical examination recently is the importance of "natural disasters" to the health and vitality of ecosystems. The necessity of natural fires for healthy and dynamic forests and grasslands is being better understood and utilized in management practices. Periodic flooding of lowlands is also being analyzed and evaluated as a natural and important part of the river and riparian ecosystem. As Molles says, "Rivers and their floodplains form a complex, highly dynamic landscape that includes river, riparian forest, marsh, oxbow lake, and wet meadow ecosystems. Historically, these ecosystems actively exchanged organisms, inorganic nutrients, and organic energy sources. The key linkage between these landscape elements (has been) periodic flooding." Floods seemingly play a vital part in maintaining the health of these types of ecosystems. Periodic flooding deposits silts for development of soils, and produces oxbow lakes and new river channels which offer new environments for supporting diverse populations of organisms. Floods also increase decomposition rates and help to recycle nutrients back to the ecosystem. Also, many fish are known to utilize floodplains for spawning, and numerous riparian plants require sustained flooding for germination of seeds and early development.

Locally, the bosque forests of the Rio Grande are being studied closely to gain an insight into the importance of periodic flooding. Studies of cottonwoods show that flooding helps their seeds to germinate and is necessary for their establishment. The cottonwood forests of the Albuquerque bosque, for the most part, date back to the early 1940’s when flooding still occurred. Since the construction of the Cochiti dam in 1942, no local flooding has occurred to help establish new growth of these trees. This has also led to the proliferation of non-native species such as the Russian olive and tamarisk.¹⁷ Numerous native animals and plants are dependent upon these riparian forests and wetland areas. As the cyclical cycles of flooding in the lowland areas around the Rio Grande have been eliminated, many species of organisms have also been placed at risk (see attached list of special status animals and plants). In fact certain species of fish, such as the Rio Grande shiner and the shovelnose sturgeon, which were once found in the river, are no longer present.

The extensive networks of diversion channels and dams that control water flow on the Rio Grande in New Mexico have also created a great deal of controversy farther downstream in Texas and Mexico. Limits on the amounts of water allowed to cross the border into El Paso have been criticized by some who propose that the river is not currently managed properly in New Mexico to provide the in-stream flow needed to sustain riparian habitats and agricultural needs in these areas. Water rights controversy has led to heated battles in the courts and news media between parties involved. Claims have been made that while Texas and Mexico have undergone tremendous droughts in the last few years, reservoirs within New Mexico have been full to the point of overflowing because of above average snowfall in the state and in Colorado.¹⁸

In 1993, American Rivers, a U.S. river conservation society listed the Rio Grande/Rio Conchos system as the most endangered river in the country.¹⁹ Concerns were expressed concerning the continued degradation of water quality from pollution due to mining along the northern section of the Rio Grande and industrial and municipal wastes seeping into the water from both sides of the Mexican/U.S. border. Also, the presence of pesticides and fertilizers from farms along the length of the river due to run-off has been detected and their effects on water supplies are being carefully examined.

If current trends continue, most scientists agree that very serious biological consequences will occur to the Middle Rio Grande riparian ecosystem. There is little question that a riparian ecosystem will be present as long as the Rio Grande continues to flow its course through the state, but many biologists express concern about the "biological quality" and "ecosystem integrity" of this riparian ecosystem.²⁰ As mentioned, the cottonwood forests are continually aging and slowly disappearing. Wetlands and marsh areas have been drained and converted to farmland. As these riparian systems diminish, the associated flora and fauna will be pushed to survive and potentially may die off. Because of this perceived threat, biologists and ecology experts are suggesting ways to prevent the slow death of the remaining native Rio Grande ecosystems.

In their "Middle Rio Grande Ecosystem: Bosque Biological Management Plan," the Middle Rio Grande Biological Interagency Team has proposed a series of recommendations that, if implemented, could potentially ensure the survival of these native Rio Grande ecosystems. Their plan, as outlined, has twenty-one recommendations. They include changes and measures that deal with hydrology and the management of surface and ground water; aquatic resources and proper use of these resources; changes dealing with terrestrial resources, such as protecting the bosque forests that already exist; enhancing monitoring and research in processes and actions that effect the Rio Grande ecosystems; implementation of a sustained plan of management of biological resources; and viewing the middle Rio Grande as part of a much larger riparian system. In all, the team sees the need not only to protect the bosque forest that already exists from development, but to expand the forest in the future. This can be done by a concerted effort to restore and maintain the fundamental processes necessary for ecosystem health and vitality. Suggestions include the renewed overbank flooding of parts of the floodplain to simulate natural perennial cycles that once existed, and to allow the river channel as much freedom to migrate within the floodplain as possible.²¹

In a study conducted by Ellis, Molles and Crawford, experimental flooding over five years in the riparian forests of the Bosque del Apache produced very interesting and promising results. Over the period of the study, it was found that seasonal flooding did in fact promote new cottonwood tree growth and increased the populations of various soil microbes and insects that are needed in a healthy riparian ecosystem. Though the results in other areas were inconclusive, the study suggests that even limited flooding can have a tremendous impact in restoring the bosque forests of the Rio Grande.

The Rio Grande River has played and will continue to play a very vital and integral role in the sustenance and continued growth of the Albuquerque metropolitan area. The river’s use has led the community and state to a certain amount of success and prosperity. Yet with the success, the continued use and disuse of the river has become an area of concern for local communities and environmental groups. It is extremely important that students learn about the Rio Grande and its role in the development of New Mexico and the Albuquerque region, and also understand issues of concern and controversy relating to the river. From this understanding, students learn to make appropriate and reasonable decisions about our community and its resources.

1. Rosner, "Albuquerque’s Natural Environment- River" Section. 1996
2. Snead, et al. 1986
3. Snead, et al. 1986
4. Crawford, et al. 1993
5. Kelley, 1982
6. Crawford, et al. 1993
7. Kelley, 1982
8. Kelley, 1982
9. Kelley, 1982
10. Bureau of Reclamation, Department of the Interior, 1977
11. Bureau of Reclamation, Department of the Interior, 1977
12. Bureau of Reclamation, Department of the Interior, 1977
13. Kelley, 1982
14. Chronic, 1987
15. Kelley, 1982
16. Bureau of Reclamation, Department of the Interior, 1976
17. Dahm, et al. 1997
18. Bureau of Reclamation, Department of the Interior, 1976
19. Bureau of Reclamation, Department of the Interior, 1976
20. Crawford, et al. 1993
21. Crawford, et al. 1993

The material detailed in this curriculum unit will be used in a unit that I currently teach on Surface and Moving Water. This unit is one part of a high school Geology and Astronomy course taught in an urban setting. Though students are inner-city dwellers, many have a connection with the Rio Grande through their own experiences or the experiences and stories of parents and grandparents. The unit has been designed to relate material currently taught, such as stream erosion, meanders and oxbows, sediment deposition, and flooding, to the local community and landforms. As mentioned earlier, the Rio Grande is an important feature of the Albuquerque area, but few students have an understanding of its dynamics and features. Most students have little appreciation for the river and its contributions to their community. Lessons will be developed to help foster this understanding and attempt to lead students to a greater appreciation of the Rio Grande and its influences on their lives.

Lesson One:

Students will simulate river processes such as meandering, oxbow formation, avulsion, etc. with stream tables. A stream table is a small scale model of a fluvial, or water, system. It is an enclosed structure in which running water (usually supplied by a hose connected to the stream table) flows through sediments, such as sand and gravel, that have been placed in the table. As the water flows, students are able to see the effects that this fluid movement has on the sediment material. Tables demonstrate the same processes that can be witnessed in natural flowing water structures, such as rivers and streams. Analysis of the movements will be done by the students, with a follow-up discussion on the Rio Grande river and its characteristics. Utilizing slides and diagrams, students should be able to see some of the same structures and characteristics that they saw with their experiments with the stream table.

Lesson Two:

After a discussion / lecture with notes, students will construct a timeline model of the Rio Grande river and its development over the last several hundred thousand years. Strong emphasis will be placed on the channelization of the river in very recent times and the quick disappearance of the riparian forests along its length. Students will build a three-dimensional model of the river as it appeared before human habitation of the Albuquerque region and after habitation. The models will be displayed in class, with students working on their model in large groups. An analysis of the changes that have occurred to the river will be required by all students in the form of a written report to accompany the models that have been built.

Lesson Three:

Students will critically analyze issues related to the current use of the Rio Grande river. Reaction papers / class discussions / debates concerning the use of the river and the damming and channelization of it will be done. Classes may also focus on issues such as measures to help preserve riparian forests and aquatic ecosystems. Students can also research methods that can be used to rescue endangered species such as the Silvery Minnow. Students will read articles recently published in the Albuquerque Journal concerning these issues and the differing points of view that are established within these articles. (See student reading list)

Lesson Four:

Students will participate in a field trip to the Rio Grande bosque and the Rio Grande Nature Center to examine cottonwood forests and the bosque ecosystem. After all classes have had the opportunity to learn about the bosque in the classroom, this will enable them to incorporate some of what they have learned with hands-on observation and analysis. On-site activities related to these field trips will be designed to engage students in observation and data recording.

Lesson Five:

Students will be required to research and develop a report or project on one of the endangered or threatened species of plants or animals found in the middle Rio Grande region. Projects must include descriptions of habitat, reasons for threat, diagrams and pictures of the plant or animal and its habitat (see attached list of special status plants and animals).

Other Possible Activities:

-Guest speakers that have been long-time residents of the community who have experienced floods in Albuquerque and can give first-hand accounts of these events.

-Guest speakers currently working on riparian ecosystems and reclamation projects can discuss their works and long-term implications of human impact on the Rio Grande.

-Activity showing how a "One-Hundred Year Flood" is determined. Develops and utilizes statistics, research and computation.

-Beginning a riparian reclamation project for the classes to work on as a community service project. Involve various resources from the community in a project designed to help the re-establishment of cottonwood and other native plant species in areas that have been taken over by non-native species. The project would include the removal of these non-native species of plants, such as tamarisk, and the planting of cottonwood seedlings in these areas. Also, the clean-up and removal of human and plant litter, and the thinning of understory growth in the area could be done. I would especially encourage parents and other family members of the students to become involved in the project as a form of community outreach. I view this as an opportunity to utilize knowledge that the students have learned in class in a very hands-on, real world application. The message is that there is a connection between the science of school and the science of everyday life.

Chronic, Halka. Roadside Geology of New Mexico. Mountain Press Publishing Company. 1987.

*A very good resource for basic geology around the state of New Mexico. The book is divided into "Trips" along various highways and points out numerous geological features and characteristics that can be seen. The introduction to the book gives a simple, fairly complete overview of the geologic history of New Mexico.

Crawford, Clifford S., Anne C. Cully, Rob Leutheuser, Mark S. Sifuentes, Larry H. White, James P. Wilbur. Middle Rio Grande Ecosystem: Bosque Biological Management Plan. U.S. Fish and Wildlife Service. 1993.

*Resource designed for anyone interested in ecosystem concerns of the Middle Rio Grande Valley. Material covered includes the history, existing conditions, future concerns, and specific recommendations for biological management of the Rio Grande river. Good illustrations to demonstrate various aspects of riparian ecosystems, and changes that have occurred in the area over time.

Dahm, C.N., T. Mulhern, P.V. Unnikrishna, H.M. Valett, M.C. Molles, Jr., C.S. Crawford. "Riparian Ecosystem Restoration: Effects of Flooding and Vegetation Type on Annual Evapotranspiration in a Semi-arid Landscape". NASA Proposal 97-NCERQA-15.

*Study on the effects of flooding in relation to the use of water by native plants.

Kelly, Vincent C.. Albuquerque, Its Mountains, Valley, Water and Volcanoes. New Mexico Bureau of Mines and Mineral Resources. 1982.

*Excellent overview of geology and the environment in the Albuquerque area. Written specifically for Albuquerque, it uses local landmarks and features to construct an overview of the region geologically and environmentally. The book has interesting photographs of how the city has changed in the last 100 years. It could be used as a high school geology book for the section of the course on local geology.

Merritts, Dorothy, Andrew De Wet and Kirsten Menking. Environmental Geology.

W. H. Freeman and Company. 1998.

*Basic college textbook that reviews elemental geology and relates the material to environmental science and ecology.

Molles, Manuel C.. Ecology, Concepts and Applications. WCB McGraw-Hill. 1999.

*Higher level college environmental science text.

Rosner, Joan and Hy. "The Albuquerque Environmental Story". Cottonwood Printing

Company. 1996. http://www.cabq.gov/aes/abqenv.html

*Website that has been developed from a resource guide from the 1970’s. Gives an overview of Albuquerque, and environmental challenges that the city faces. Written to be used by teachers with many activities for the classroom. Primarily geared for younger students from elementary through middle school.

Siegel, Lee. "Rivers Reshaped: USU Scientist Suggests We Rethink Our Water Ways". Salt Lake Tribune. December 12, 1998.

*Newspaper article that analyzes how science is now starting to think about how past river management practices may have a long term impact on various environment and ecological systems.

Snead, Rodman and Steve Reynolds. "Surface Hydrology" from New Mexico in Maps.

University of New Mexico Press. 1986.

*Numerous maps of New Mexico, from geological to political. The Surface Hydrology map shows all the major rivers and streams in New Mexico and how these feed into larger ones.

U.S. Department of Interior Bureau of Reclamation. New Mexico Water Resources: Assessment For Planning Purposes. 1976.

*Description of the history of water management practices in New Mexico and future projects designed to effectively utilize the Rio Grande river for agricultural, residential and industrial use. Gives a detailed description of projects that have been done in the past and why they were instituted.

U.S. Department of the Interior Bureau of Reclamation. Environmental Impact Statement: Operation and Maintenance Program for the Rio Grande- Velarde to Caballo Dam. 1977.

*An environmental impact statement analyzing possible changes and effects construction of various water resource projects have had and will have on the Rio Grande and surrounding areas. Good photos and maps of projects.

Windell, John T., PhD. Stream Riparian and Wetland Ecology. University of Colorado. Fall, 1992.

*Good detailed text on streams and stream factors, include both biotic and abiotic. Excellent resource for Biology teachers wishing to add stream ecology to their curricula. Very complete glossary of terms.

The Albuquerque Environmental Story by Joan and Hy Rosner. Selected sections that can be printed off or accessed by computer from the internet. http://www.cabq.gov/aes/abqenv.html

Albuquerque: Its Mountains, Valley, Water and Volcanoes by Vincent C. Kelley. Selected readings.

"Safeguard for Minnow Starts Today" from the Albuquerque Journal, June 23, 1999. Article by Mike Taugher.

"Report: Dying River Needs Changes" from the Albuquerque Journal, June 27, 1999. Article by Mike Taugher.

Teacher Resources

I. Glossary of Terms

Acre-feet: amount of water covering one acre (43,560 sq. ft.) to a depth of one foot.

Aggradation: the process by which material is deposited within a channel as a result of sediment overloading.

Alluvium: sediments transported and deposited by streams and rivers.

Arroyo: a dry gully, rivulet or stream.

Avulsion: a sudden shift of a river channel from one part of the valley floodplain to another through the development of a new course; also known as pattern movement.

Bosque: a small wooded area associated with riparian habitat.

Braided stream: stream characterized by multiple channels that divide and rejoin; indicative of an unstable stream ecosystem.

Channelization: the artificial straightening, stabilizing, or diverting of rivers resulting in straighter and deeper channels.

Fluvial: materials that are transported and deposited by streams; usually rounded, sorted into layers and poorly compacted.

Flood plain: a nearby flat landform composed of sediment that lies on either side of a stream and is commonly underwater during floods.

Meander: a stream reach that includes one complete bend, curve or loop.

One-hundred year flood: a regulatory standard that is based on statistical analysis of historical flooding of a river or stream, useful for planning in an attempt to control floods and provide flood insurance.

Oxbow: area of a stream, cut off by meandering processes; often develops into wetland habitat for riparian plants and animals.

Riparian: areas bordering streams, lakes, rivers, and other water courses; usually having high water tables and are capable of supporting plants that require saturated soils during all or part of the year.

Sediment load: quantity of solid material that can be transported by a stream or river.

Siltation: process by which a river or stream becomes clogged with sediments.

Wetland: general term that includes different landscapes covered by shallow and sometimes intermittent waters; such as bogs, swamps, and marshes.

Yazoo: low areas of the floodplain that are found alongside rivers and are in constant risk of flooding.

II. Special Status Plants and Animals of the Middle Rio Grande-

FE = federally endangered
C2 = category 2 federal candidate
FT = federally threatened
SE = state listed endangered
FP = federally proposed for listing
SS = state listed sensitive
C1 = category 2 federal candidate
BC = Biological Interagency Team species of concern

Brimblecombe, S., Gallannaugh, D., & Thompson, C. et al, 1998. QPB Science Encyclopedia. Helicon Publishing Group Ltd.: New York.
    This book is a really great resource for all those little questions that are eating away at the back of your head. Most of the entries are short enough so that the         science educated person can quickly read it and say, "Oh yes, I remember that now…"

McCormick, C. & Pressley, M., 1997. Education Psychology: Learning, Instruction, Assessment. Addison Wesley Longman Inc.: New York.    
    This was a textbook for an introductory class in education psychology. I have used this book on many occasions to help me get the research behind my          students’ behavior. Definitely a well used book in my household.

McFadden, L., 1999. Lecture Notes.
    Sorry I can’t get you a copy. Les was a wonderful leader for our summer course. I learned so much about soils and why they are important, that is why this          curriculum unit was made.

Merrits, D., De Witt, A., & Menking, K., 1998. Environmental Geology: An Earth System Science Approach. W.H. Freeman and Company: NewYork.
    This book has so many great ideas for teaching Earth science. Merrits takes an orthodox point of view on teaching Earth science. Although this is designed for     freshman college level classes, the information is written at a level and in a way that high school students can understand. It might be a little too advanced for         middle school.

Molles, M., 1999. Ecology: Concepts and Applications. WCB/McGraw-Hill Companies: Boston.
    Great source for examples! Molles explains study after study and relates them to the content. For example, he talks about cicadas that sweat, but first he goes      through the entire atmospheric conditions that would be ideal for sweating organisms. He also talks about the scientific process that goes into the discovery of          sweating bugs. This would be a really neat class to teach or learn more about.

Spaudling, N. & Namowitz, S., 1997. Heath Earth Science. McDougal Littell: Evanston, Illinois.
    This is a basic Earth science high school textbook. This is the text that my students will be using so I thought I should use some of the terms and concepts              addressed in the book. Although soils were left out, I plan on supplementing the text with this curriculum unit.