Inspired by the books and lectures of geomorphologist Ellen Wohl (Colorado State University), "Meander" explores how you can understand the health of a river by looking at its shape. In addition, it considers the various impacts of human activity on riparian (wetlands adjacent to rivers) ecosystems.
The overall thesis is that rivers naturally tend towards "complex" shapes, whereas human activity tends to straighten them and reduce complexity. For example, in their natural state, rivers will tend to move freely across valley floors, periodically overtopping their banks and fertilizing the surrounding forest. However, human transportation corridors are often developed alongside rivers, and thereby constrain them into narrow, straighter channels.
One result of this is that the surrounding forests are not replenished with the nutrients that large river floods provide, and start to degrade and die off. Additionally, the straightening of the river reduces the complexity under the surface, making the overall flow speed of the river more uniform. This is distressing for many fish species, as they depend on slower and faster moving water for various different functions during their life cycle.
C3 Scale Proportion and Quantity. Students recognize natural objects and observable phenomena exist from the very small to the immensely large. They use standard units to measure and describe physical quantities such as weight, time, temperature, and volume.
C4 Systems and System Models. Students understand that a system is a group of related parts that make up a whole and can carry out functions its individual parts cannot. They can also describe a system in terms of its components and their interactions.
C7 Stability and Change. Students measure change in terms of differences over time, and observe that change may occur at different rates. Students learn some systems appear stable, but over long periods of time they will eventually change.
C2 Cause and Effect. Students classify relationships as causal or correlational, and recognize that correlation does not necessarily imply causation. They use cause and effect relationships to predict phenomena in natural or designed systems. They also understand that phenomena may have more than one cause, and some cause and effect relationships in systems can only be described using probability.
C4 Systems and System Models. Students can understand that systems may interact with other systems; they may have sub-systems and be a part of larger complex systems. They can use models to represent systems and their interactions—such as inputs, processes and outputs—and energy, matter, and information flows within systems. They can also learn that models are limited in that they only represent certain aspects of the system under study.
C5 Energy and Matter. Students learn matter is conserved because atoms are conserved in physical and chemical processes. They also learn within a natural or designed system, the transfer of energy drives the motion and/or cycling of matter. Energy may take different forms (e.g. energy in fields, thermal energy, energy of motion). The transfer of energy can be tracked as energy flows through a designed or natural system.
C7 Stability and Change. Students explain stability and change in natural or designed systems by examining changes over time, and considering forces at different scales, including the atomic scale. Students learn changes in one part of a system might cause large changes in another part, systems in dynamic equilibrium are stable due to a balance of feedback mechanisms, and stability might be disturbed by either sudden events or gradual changes that accumulate over time
C2 Cause and Effect. Students understand that empirical evidence is required to differentiate between cause and correlation and to make claims about specific causes and effects. They suggest cause and effect relationships to explain and predict behaviors in complex natural and designed systems. They also propose causal relationships by examining what is known about smaller scale mechanisms within the system. They recognize changes in systems may have various causes that may not have equal effects.
C4 Systems and System Models. Students can investigate or analyze a system by defining its boundaries and initial conditions, as well as its inputs and outputs. They can use models (e.g., physical, mathematical, computer models) to simulate the flow of energy, matter, and interactions within and between systems at different scales. They can also use models and simulations to predict the behavior of a system, and recognize that these predictions have limited precision and reliability due to the assumptions and approximations inherent in the models. They can also design systems to do specific tasks.
C5 Energy and Matter. Students learn that the total amount of energy and matter in closed systems is conserved. They can describe changes of energy and matter in a system in terms of energy and matter flows into, out of, and within that system. They also learn that energy cannot be created or destroyed. It only moves between one place and another place, between objects and/or fields, or between systems. Energy drives the cycling of matter within and between systems. In nuclear processes, atoms are not conserved, but the total number of protons plus neutrons is conserved.
C6 Structures and Functions. Students investigate systems by examining the properties of different materials, the structures of different components, and their interconnections to reveal the system’s function and/or solve a problem. They infer the functions and properties of natural and designed objects and systems from their overall structure, the way their components are shaped and used, and the molecular substructures of their various materials.
C7 Stability and Change. Students understand much of science deals with constructing explanations of how things change and how they remain stable. They quantify and model changes in systems over very short or very long periods of time. They see some changes are irreversible, and negative feedback can stabilize a system, while positive feedback can destabilize it. They recognize systems can be designed for greater or lesser stability
ESS2.A Earth Materials and Systems. Four major Earth systems interact. Rainfall helps to shape the land and affects the types of living things found in a region. Water, ice, wind, organisms, and gravity break rocks, soils, and sediments into smaller pieces and move them around
ESS2.C The Roles of Water in Earth's Processes. Most of Earth’s water is in the ocean and much of the Earth’s fresh water is in glaciers or underground.
ESS2.E Biogeology. Living things can affect the physical characteristics of their environment.
ESS3.B Natural Hazards. A variety of hazards result from natural processes; humans cannot eliminate hazards but can reduce their impacts.
ESS3.C Human Impact on Earth systems. Societal activities have had major effects on the land, ocean, atmosphere, and even outer space. Societal activities can also help protect Earth’s resources and environments.
LS2.A Interdependent Relationships in Ecosystems. The food of almost any animal can be traced back to plants. Organisms are related in food webs in which some animals eat plants for food and other animals eat the animals that eat plants, while decomposers restore some materials back to the soil.
LS4.D Biodiversity & Humans. Populations of organisms live in a variety of habitats. Change in those habitats affects the organisms living there
ESS2.A Earth Materials and Systems. Energy flows and matter cycles within and among Earth’s systems, including the sun and Earth’s interior as primary energy sources. Plate tectonics is one result of these processes.
ESS2.C The Roles of Water in Earth's Processes. Water cycles among land, ocean, and atmosphere, and is propelled by sunlight and gravity. Density variations of sea water drive interconnected ocean currents. Water movement causes weathering and erosion, changing landscape features.
ESS2.E Biogeology. Evolution is shaped by Earth’s varying geological conditions. Sudden changes in conditions (e.g., meteor impacts, major volcanic eruptions) have caused mass extinctions, but these changes, as well as more gradual ones, have ultimately allowed other life forms to flourish, which have in turn changed the rates of weathering and erosion of land surfaces, altered the composition of Earth’s soils and atmosphere, and affected the distribution of water in the hydrosphere.
ESS3.B Natural Hazards. Mapping the history of natural hazards in a region and understanding related geological forces can help forecast the locations and likelihoods of future events, such as volcanic eruptions, earthquakes and severe weather.
ESS3.C Human Impact on Earth systems. Human activities have altered the biosphere, sometimes damaging it, although changes to environments can have different impacts for different living things. Activities and technologies can be engineered to reduce people’s impacts on Earth.
LS2.A Interdependent Relationships in Ecosystems. Organisms and populations are dependent on their environmental interactions both with other living things and with nonliving factors, any of which can limit their growth. Competitive, predatory, and mutually beneficial interactions vary across ecosystems but the patterns are shared.
LS2.B Cycles of Matter and Energy Transfer in Ecosystems. The atoms that make up the organisms in an ecosystem are cycled repeatedly between the living and nonliving parts of the ecosystem. Food webs model how matter and energy are transferred among producers, consumers, and decomposers as the three groups interact within an ecosystem.
LS2.C Ecosystem Dynamics, Functioning and Resilience. Ecosystem characteristics vary over time. Disruptions to any part of an ecosystem can lead to shifts in all of its populations. The completeness or integrity of an ecosystem’s biodiversity is often used as a measure of its health.
LS4.D Biodiversity & Humans. Changes in biodiversity can influence humans’ resources and ecosystem services they rely on.
ESS2.A Earth Materials and Systems. Feedback effects exist within and among Earth’s systems.The geological record shows that changes to global and regional climate can be caused by interactions among changes in the sun’s energy output or Earth’s orbit, tectonic events, ocean circulation, volcanic activity, glaciers, vegetation, and human activities.
ESS2.C The Roles of Water in Earth's Processes. The planet’s dynamics are greatly influenced by water’s unique chemical and physical properties.
ESS2.E Biogeology. The biosphere and Earth’s other systems have many interconnections that cause a continual co-evolution of Earth’s surface and life on it
ESS3.C Human Impact on Earth systems. Sustainability of human societies and the biodiversity that supports them requires responsible management of natural resources, including the development of technologies that produce less pollution and waste and that preclude ecosystem degradation.
LS2.A Interdependent Relationships in Ecosystems. Ecosystems have carrying capacities resulting from biotic and abiotic factors. The fundamental tension between resource availability and organism populations affects the abundance of species in any given ecosystem.
LS2.B Cycles of Matter and Energy Transfer in Ecosystems. Photosynthesis and cellular respiration provide most of the energy for life processes. Only a fraction of matter consumed at the lower level of a food web is transferred up, resulting in fewer organisms at higher levels. At each link in an ecosystem elements are combined in different ways and matter and energy are conserved. Photosynthesis and cellular respiration are key components of the global carbon cycle.
LS4.D Biodiversity & Humans. Biodiversity is increased by formation of new species and reduced by extinction. Humans depend on biodiversity but also have adverse impacts on it. Sustaining biodiversity is essential to supporting life on Earth