Groundwater

Contents

Agenda for the Day

Upper Anchor for Soil Water and Groundwater

Learning Progression Levels for Groundwater

Examples of Student Responses to Groundwater FAs

Student Learning and Instructional Activity Table: Exploring Groundwater

Exploring Groundwater Activity Sequence

Student Learning and Instructional Activity Table: Exploring Groundwater - Completed

Scientific Practices and Instructional Activities: Groundwater

Teacher Practices and Instructional Activities: Groundwater

Exploring Groundwater Activity Sequence

Activity 1: Permeability

Activity 2: Exploring With Groundwater Models

Activity 3: Application Assessment: Where Would You Drill A Well?

Activity 4: Get the Groundwater Picture

Agenda for the Day

Day #3 Groundwater

8:30Loose ends from previous Day

8:45Scientific Practices: Explanations and Argument

9:15Introduction to groundwater

  • Student thinking about soil and groundwater
  • Upper anchor for soil and groundwater

9:45Break

10:00Groundwater Formative Assessments

  • Version #1
  • Version #2

11:00Permeability Activity & Tools for Reasoning

  • Pathways Tools
  • Drivers and Constraints Tools

11:30 Lunch

12:15Groundwater Models

1:45Get the Groundwater Picture

2:45 Break

3:00Continuation of Milltown Issue

4:00School year project activities

4:30Done

Upper Anchor for Soil Water and Groundwater

Structure of the Soil/Groundwater System: The soil and rocks undergrounds are heterogeneous. There are different soil horizons and stratigraphic layers that have different porosity and permeability values. Aquifers above impermeable layers (open to the surface) are unconfined. Aquifers below impermeable layers are confined.

  • Macroscopic to Microscopic Scale: Water underground is stored in cracks and small spaces between sediment grains. When water fills the pore spaces completely, the sediment is saturated. The top of the saturated zone is the water table.
  • The capacity of geologic materials (e.g., soil, sandstone, shale) to hold water is determined by the porosity of the material. Porosity is the volume of the pore spaces and cracks. Smaller grain sizes have higher porosity (e.g., clay, shale). Larger grain sizes have lower porosity (e.g., gravel).
  • Permeability is a measure of the ability of a porous material to allow fluids to pass through it. Permeability depends on the connectedness of the pore spaces in materials.Larger sediment grain sizes (e.g., gravel, sandstone) = higher permeability. Smaller sediment grain sizes (e.g., clay, shale) = lower permeability. If water is able to flow (or be pumped) into and out of the saturated zone of a material at a rate that is useable by people (i.e., if the material is sufficiently permeable), it is called an aquifer. Impermeable layers are called aquitards or aquicludes.
  • Large (Landscape) Scale: Stratigraphic layers can cover great distances underground. In unconfined aquifers, the top of the water table generally follows topography. Therefore, surface water divides are usually also groundwater divides.

Processes in Watersheds: Water infiltrates into the small pore spaces between grains of sediment or into cracks in crystalline rocks, displacing the air that is in those spaces. Water can move through permeable materials in both horizontal and vertical dimensions. Water can leave the soil/groundwater system where the water table intersects the surface, when wells pump water from aquifers, bybeing absorbed into plant roots and transpired back into the atmosphere, or where soil water is close to the surface, by being evaporated directly into the atmosphere.

Scientific Principles: Water moves into, through, and out of the soil and groundwater system according to scientific principles.

  • Drivers:
  • Gravity This force is the main driverin unconfined aquifers and is the reason why in general, groundwater follows surface topography.
  • Pressure (also called hydraulic head). This driver is important in confined aquifer systems because the fluid pressure may be greater than gravity. Water moves from areas of high pressure (high potential energy) to areas of low pressure (low potential energy). This driver can move water in any direction, including pulling water upwards in wells or pushing it upwards in artesian springs.
  • At the microscopic scale, capillary forces are important. Adhesion between organic material in soil and water molecules,and surface tension (cohesion between water molecules) causes water within the small pore spaces to move upwards or to dry surfaces.
  • Constraints: The rate and volume of infiltration is constrained by
  • Permeability – Higher permeability results in higher infiltration.
  • Porosity – Water will not infiltrate into saturated areas.
  • Vegetative cover – More vegetation may slow down runoff and increase infiltration rates.

Representations: Stratigraphy is represented on cross-sections. Soil and groundwater can be modeled and represented using cross-section diagrams.

Dependency & Human Agency: Infiltration and aquifer recharge rates can vary from a few feet a day to only inches per year. Therefore, in many areas, withdrawal of water from aquifers can result in a drop in the water table.

Learning Progression Levels for Groundwater

Level 4: Model-Based Accounts

Level 4 accounts trace water into and out of the soil/groundwater systems at multiple scales and along multiple pathways, include reference to driving forces and constraining variables that define possible pathways for water underground, use representations such as cross-sections to trace water, and consider implications of human connections to groundwater systems.

Level 3: School Science Accounts

Level 3 accounts tell school science stories about groundwater. They trace water into the soil and eventually into groundwater or aquifers along multiple steps and pathways.

Structure & Systems: Accountsrecognize that water underground is in pore spaces, although the scale of these pore spaces may be too large or too small. They recognize that the groundwater and surface water systems are connected, although accounts are more likely to describe water infiltrating into the ground and are less likely to trace water from an aquifer into surface water (e.g., a river) unless specifically prompted.

Scale: Can trace water underground at landscape scales. May not recognize scale of pore spaces in underground systems.

Scientific Principles: Accounts usually names processes such as infiltration. They do not consider how gravity, pressure, or permeability constrain water movements.

Representations: Can trace water through cross-sections, but do not usually reason about constraining factors on groundwater flow. Thus, they may trace water through the groundwater across watershed boundaries in unconfined aquifer systems even though this is an unlikely path.

Dependency & Human Agency: Recognizes that human actions have impacts on environmental systems. May reason that pumping from wells can impact the water level in aquifers. May not recognize in principled ways the limitations of human agency.

Level 2: Force-Dynamic Accounts with Mechanisms

Compared with level 1, level 2 accounts show an expanded awareness of and experience with the physical world. These accounts provide more sophisticated force-dynamic explanations and predictions about water. Most significantly, mechanisms to move water or change water are included (compared with level 1, in which no mechanisms are included).

Structure & Systems: Level 2 pictures show water in open spaces underground, such as in underground rivers, lakes, or caverns. Often depicts wells as the iconic stone cylinder with a bucket and rope (Jack & Jill well). May not recognize how surface and groundwater systems interact.

Scale: Focus is on visible macroscopic scale at familiar distances.

Scientific Principles: Includes mechanisms for water moving into the soil or ground. Mechanisms describe agents (often inanimate things in natural systems) doing something to the water, such as the ground absorbing the water. Accounts may also describe natural tendencies of water (sinking into the ground) or describe familiar experiences, such as water and dirt will make mud. Accounts may refer to special circumstances, such as groundwater may get into a bathtub if the bathroom is in the basement. For example, river water can enter a well if the river overflows into the top of the well.

Representations: Recognizes limited connections between representations and the physical world. For example, reasons about maps in two dimensions (horizontal) but does not consider the third (vertical) dimension. May describe cross-sections.

Dependency & Human Agency: Humans benefit or are impacted by movements of water underground if the conditions are right.

Level 1: Force-Dynamic Accounts

Level 1 accounts of water focus on water in visible systems at macroscopic scales. At this level, accounts explain that water goes into the ground, but once that water is no longer visible, the water is considered to be gone, or to have essentially disappeared.

Structure & Systems: Drawings of underground systems tend to depict water in tanks or pipes only. They provide anthropocentric sources for groundwater, such as from toilets or sewers.

Scale: Accounts focus on macroscopic, visible water or water in familiar places.

Scientific Principles: Accounts do not trace water into other systems. Accounts may say that water “goes” into the ground, but do not say how or what happens to the water once it gets there. Typically, the view is that water that goes underground is not re-available for use.

Representations: Drawings of water underground show water in pipes or tanks.

Dependency & Human Agency: These accounts portray people as the sources and movers of water underground.

Examples of Student Responses to Groundwater FAs

Student Drawing / Level / Notes on levels or foci for instruction
1 / V 1
2 / V 2
3 / V 1
4 / V1
5 / V2
6 / V2
7 / V2
8 / V2

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Student Learning and Instructional Activity Table: Exploring Groundwater

What students need to work on (Foci for instruction) / Permeability / Groundwater Models & Where to put a well / Get the Groundwater Picture
Structure & Systems:
Scale
Scientific Principles
Representations
Dependency & Human Agency

Exploring Groundwater Activity Sequence

Activity/Description / Learning Goals – Practices fused with content / Formative Assessments / Drivers & Constraints / Representations / Tools
Permeability
Students pour water into cups of gravel, sand, and clay to see what happens to the water. / -Investigate and analyze and interpret data about permeability
-Construct explanations for groundwater infiltration rates / Groundwater 1
Groundwater 2 / -Gravity pulls water down;
-Permeability constrains infiltration rates / Physical models / -Drivers & Constraints tool to reason about permeability rates
Exploring with Groundwater Models
Students use groundwater models to investigate groundwater movement / -Use models to explore groundwater systems
-Investigate and analyze and interpret data from wells
-Construct explanations about water movements in groundwater systems / Groundwater 1
Groundwater 2 / -Gravity pulls water down; pressure pushes water to areas of low pressure
-Permeability constrains infiltration rates / -Physical models
-Cross-section diagrams / -Drivers and Constraints tool to reason about possible pathways for water underground
Where would you put a well?
Given a map/cross-section, students are asked to suggest a location for a new well / -Investigate and analyze and interpret data about wells
-Construct arguments from evidence about where to locate a well / Groundwater 1
Groundwater 2 / -Gravity pulls water down; pressure pushes water to areas of low pressure
-Permeability constrains infiltration rates / Cross-section diagrams / -Drivers and Constraints tool to reason about possible pathways for water underground
Get the Groundwater Picture
Students use well data to construct a cross-section and then use the cross-section to analyze the groundwater system. / -Use cross-section representations to locate and trace water in the groundwater system
-Analyze and interpret well log data to predict groundwater movements
-Construct predictions for water movements through a groundwater system / Groundwater 1
Groundwater 2 / -Gravity pulls water down; pressure pushes water to areas of low pressure
-Permeability constrains infiltration rates / Cross-section diagrams / -Drivers and Constraints tool to reason about possible pathways for water underground

Student Learning and Instructional Activity Table: Exploring Groundwater - Completed

What students need to work on (Foci for instruction) / Permeability / Groundwater Models & Where to put a well / Get the Groundwater Picture
Structure & Systems: / Recognizing that water exists in cracks and pore spaces (L2 to L3)
Recognizing connections between surface and soil/groundwater systems (L2 to L3 and L3 to L4) / Investigate location of water in different sediments (L2 to L3) / Investigate and trace movement of water through underground systems (L2 to L3 and L3 to L4) / Trace water through underground systems (L2 to L3 and L3 to L4)
Scale / Describing groundwater systems at landscape scales (L2 to L3)
Recognizing scale of pore spaces in underground systems (L3 to L4) / Examining the size of pore spaces and the influence on permeability rates (L2 to L3 and L3 to L4) / Investigating water movements through pore spaces at the macroscopic scale (L2 to L3 and L3 to L4) / Tracing water through underground systems at landscape scales (L2 to L3)
Scientific Principles / Moving from force-dynamic agents to processes of infiltration to describe water movements (L2 to L3)
Moving from naming processes to considering drivers (gravity & pressure) and constraints (permeability) on processes to move water in underground systems (L3 to L4) / Investigate permeability of different sediments (L2 to L3 and L3 to L4) / Using scientific principles to explain water movements and to predict the best location of a well (L2 to L3 and L3 to L4)
Writing Accounts (Explaining & Predicting) of water pathways (L2 to L3 and L3 to L4) / Tracing water through underground systems (L2 to L3)
Considering the influence of gravity, pressure, and permeability to trace water through underground systems (L3 to L4)
Writing Accounts (Explaining & Predicting) of water pathways (L2 to L3 and L3 to L4)
Representations / Using cross-sections to trace water in underground systems ( L2 to L3)
Reasoning about drivers and constraints from cross-sections (L3 to L4) / Drawing cross sections and using cross-sections to explain, predict, and make arguments (L / Using cross-sections to trace water and explain, predict, and make arguments about water flow (L2 to L3 to L4)
Dependency & Human Agency / Recognizing how humans impact and are impacted by movements of water underground (L2 to L3)
Recognizing the limitations of the groundwater system to provide fresh water (L3 to L4). / Using cross-sections to explain and predict groundwater movements and well locations (L2 to L3 to L4) / Using cross-sections to trace water and explain, predict, and make arguments about water flow (L2 to L3 to L4)

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Scientific Practices and Instructional Activities: Groundwater

What Students Need to Work On (Foci for Instruction) / Permeability / Groundwater Models & Where Would You Put Well / Get the Groundwater Picture
Practices / Using Models / Using models to develop understanding of an otherwise invisible system (i.e., groundwater). / Using models to develop understanding of particle size, permeability, and water movement. / Using groundwater models to explore this system. Drawing and interpreting cross-section diagrams of groundwater system. / Constructing cross-section of groundwater system to develop understanding of groundwater flow.
Investigating, Analyzing,
Interpreting Data / Using first-hand experiences with models of sediments and the groundwater system to explore, analyze & interpret how water flows through the ground. / Testing with different sediment/particle sizes to investigate permeability through different materials. / Interpreting observations/data of pumping in a groundwater model to make inferences about locations of hidden well bottoms.
Analyzing cross-section to decide where to build a well. / Students us well data to construct a cross-section and then use the cross-section to analyze the groundwater system.
Constructing Explanations / Moving from force-dynamics & informal rules to considering drivers (gravity, pressure) & constraints (permeability, statigraphy) to explain movement of water in ground. / Using D&C Tool and constructing explanations about drivers and constraints that govern permeability of different materials. / Using D&C Tool to explain how gravity and pressure drive groundwater and how permeability and statigraphy constrain groundwater. Applying explanations in “Where would you put well?” assessment. / Students can construct explanations of where water flows in the represented cross-section.
Arguments From Evidence (& Social Construction) / Developing, defending & evaluating arguments & explanations using experience, evidence & scientific principles in social context (i.e., peer to peer). / Sharing permeability explanations with peers. / Developing, sharing, defending, and evaluating with peers arguments about where well bottoms are located and where to build well.
What Students Need to Work On (Foci for Instruction) / Permeability / Groundwater Models & Where Would You Put Well / Get the Groundwater Picture
Cross-Cutting Concepts / Scale, Proportion & Quantity / Relating size of sediment particles to permeability, and permeability to groundwater movement. / Investigating how size of sediment relates to permeability. / Developing understanding of size of pore spaces underground (generally not large open lakes or rivers). / Translating between scale of cross-section diagram and scale in real world.
Systems System Models / Developing understanding of groundwater system (which is usually invisible to us). / Examining groundwater system materials in macroscopic scale model, which can then be extrapolated to larger scale groundwater systems. / Developing understanding of the structure of groundwater systems using a small-scale model. / Developing understanding of the structure of groundwater systems through constructing and using a cross-section diagram.
Flow & Conservation of Matter / Tracing water into, through and out of the groundwater system. / Examining water flow through different sediment sizes. / Connecting structure of groundwater systems to how water flows into, through and from groundwater system. / Using a cross-section diagram to consider groundwater flow through different materials.
Stability & Change / Recognizing how groundwater is recharged and how natural events (e.g., drought) and human actions (e.g., pumping of groundwater) can change the amount of groundwater that is available. / Examining how quickly water can be infiltrated or extracted from different sediment types. / Examining how pumping of groundwater can impact amount and movement of water in groundwater system. / Examining how groundwater system can change through actions such as pumping and/or introducing pollutants.

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