what is a watershed? implications of student conceptions for environmental science education and the...

LEARNING

Joseph Krajcik and Maria Varelas, Section Coeditors

What Is a Watershed? Implicationsof Student Conceptions forEnvironmental Science Educationand the National ScienceEducation Standards

DANIEL P. SHEPARDSONDepartment of Curriculum and Instruction, Purdue University, West Lafayette,IN 47907-2098, USADepartment of Earth and Atmospheric Sciences, Purdue University, West Lafayette,IN 47907-2051, USA

BRYAN WEE, MICHELLE PRIDDY, LAUREN SCHELLENBERGERDepartment of Curriculum and Instruction, Purdue University, West Lafayette,IN 47907-2098, USA

JON HARBORDepartment of Geography and Environmental Sciences, University of Colorado at Denverand Health Sciences Center, Denver, CO 80217, USA

Received 7 September 2006; revised 19 January 2007; accepted 22 January 2007

DOI 10.1002/sce.20206Published online 8 March 2007 in Wiley InterScience (www.interscience.wiley.com).

Correspondence to: Daniel P. Shepardson; e-mail: [email protected] grant sponsor: National Science Foundation (NSF).Contract grant number: 9819439-ESI.The opinions, findings, and conclusions or recommendations expressed in this paper are those of the

authors and do not necessarily reflect the views of the NSF.

C© 2007 Wiley Periodicals, Inc.

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ABSTRACT: The purpose of this study was to investigate students’ conceptions aboutwatersheds. Specifically: (1) What are students’ conceptions of a watershed? and (2) Inwhat ways might students’ conceptions vary by grade level and community setting? Thisstudy was descriptive in nature and reflected a cross-age design involving the collection ofqualitative data from 915 students from the Midwest, United States. These qualitative datawere analyzed for their content in an inductive manner, identifying student’s conceptions.This content analysis was followed with a statistical analysis to determine the significance inthe frequency of the identified student conceptions. Four categories emerged that reflectedthese students’ conceptions. Based on these findings, we make curricular recommendationsthat build on the students’ conceptions, the watershed concept, and the National ResearchCouncil (1996) Science Education Standards. C© 2007 Wiley Periodicals, Inc. Sci Ed 91:554 –578, 2007

INTRODUCTION

Although a number of studies have investigated students’ conceptions about the earth’sshape and gravity (e.g., Baxter, 1989; Nussbaum, 1985), lunar phases (e.g., Baxter, 1989;Stahly, Krockover, & Shepardson, 1999), rocks and rock cycle (e.g., Happs, 1985), andseasons (e.g., Baxter, 1989), research in the area of students’ conceptions about geosciencephenomena lacks the breadth necessary to support large-scale insights and models(Manduca, Mogk, & Stillings, 2002). Related research in environmental education tendsto focus on students’ factual knowledge about environmental issues, and their environ-mental attitudes, and less on student conceptions of the environment (Rickinson, 2001).Thus, it is essential for research in geoscience and environmental education to continue toexpand our understanding of students’ conceptions about geoscientific phenomena and theenvironment (Payne, 1998), as the foundation for informing standards and curriculum ingeoenvironmental science education.

Within environmental education, there has been little research to date that investigatesstudents’ conceptualizations of watersheds (also known as catchments and river basins).This is surprising given that the watershed concept has wide-ranging application in envi-ronmental science, in our everyday lives (people live, work, and play in watersheds), andin environmental regulations. Understanding a watershed as a complex, natural system isessential to sustaining environmental integrity and health (Haury, 2000), and many landand water pollution issues are watershed based. In order to protect water resources, it isessential to consider land surface areas, water bodies, and their interactions because watertransported across the land and through surface water systems distributes the effects ofhuman activities throughout a watershed (Environmental Protection Agency [EPA], 1996).By providing a coherent organizational framework for thinking about and managing waterresources (EPA, 1996), the watershed concept can be a powerful learning tool that canmotivate students to engage in environmentally responsible behaviors.

Once individuals become aware of and interested in their watershed, they often becomemore involved in decision-making as well as hands-on protection and restoration efforts.Through such involvement, watershed approaches build a sense of community, help reduceconflicts, increase commitment to the actions necessary to meet environmental goals, andultimately, improve the likelihood of success for environmental programs. (EPA, 1996)

Although a number of curricular programs and materials (e.g., Adopt-A-Watershed,The Rivers Project Curriculum, Earth Force—Global Rivers Environmental EducationNetwork) have been developed to teach students about watersheds, these programs weredesigned with little consideration of student conceptions. These conceptions may or may not

Science Education DOI 10.1002/sce

556 SHEPARDSON ET AL.

fit current scientific perspectives because students’ conceptions are built on a combinationof unique personal and social experiences (Driver, Guesne, & Tiberghien, 1985).Consequently, these educational programs lack what Driver, Squires, Rushworth, andWood-Robinson (1994) called curricular continuity, a sequence of experiences that buildfrom students’ conceptions toward scientific understanding. The purpose of this study,therefore, was to investigate students’ conceptions about watersheds, add to the extantliterature base on students’ geoscience and environmental science learning, and provideguidance to curricular development. Specifically, the research questions guiding this studywere as follows:

1. What are students’ conceptions of a watershed?2. In what ways might students’ conceptions vary by grade level and community setting?

Based on these findings, we make curricular recommendations that build on the students’conceptions, the watershed concept, and the National Research Council (NRC; 1996) Sci-ence Education Standards.

Significance of Study

An understanding of the watershed concept is essential to comprehending issues aboutwater quality, point and nonpoint source pollution, and the impact of land use practices andpersonal actions on watersheds (Patterson & Harbor, 2005). This is salient given that land isundergoing rapid change in terms of urban development worldwide; for example, built-upareas have increased by almost 50% in the last 15 years in the United States (NationalResources Conservation Service [NRCS], 2004). Only through a deeper understanding ofthe watershed concept will people benefit from or comprehend watershed managementstrategies (National Environmental Education Training Foundation [NEETF], 1999a):

. . . having a real understanding of watersheds and how they affect the daily lives ofindividuals and the community can translate into increased interest in localized efforts tomonitor and protect water quality and riparian habitats. (p. 1)

Most citizens, however, are not knowledgeable about the watershed concept, nor do theyfully understand the hydrologic connection (NEETF, 2005; Schueler & Holland, 2000). Forexample, only 41% of adults have any idea what a watershed is, only 22% know that stormwater runoff is a major cause of stream pollution within a watershed (NEETF, 1999b), andwe know very little about how students’ conceptualize a watershed. Therefore, if scienceeducation is to promote a citizenry that is knowledgeable about watersheds and effectiveresource management, it is essential to determine how students conceptualize watersheds(Osborne & Freyberg, 1987) in order to plan curriculum and design instruction that buildson these conceptions (Driver et al., 1994).

BACKGROUND

Although the watershed is an important environmental concept, little is known abouthow students conceptualize a watershed. Only two studies have specifically investigatedstudents’ conceptions of a watershed. In a small-scale study of sixth- (n= 28), seventh-(n= 25), eighth- (n= 22), and ninth- (n= 23) grade students from Indiana, Shepardson,Harbor, and Wee (2005) found that students’ conceptions about watersheds were limited tomountainous terrain as well as land areas of high relief and elevation, all of which did not


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resemble the topography of watersheds in areas where the students lived. In addition, wa-tershed hydrology was typically restricted to precipitation, evaporation, and condensation;and watershed structure was equated to streams and rivers. In other words, students werefocused on water-related areas and processes; none of them indicated that water or othermaterials on land would be transported into the rivers and streams within the watershedand further transported through the watershed. Thus, students did not see the connectionsbetween land use, water drainage, and water quality (point vs. nonpoint source pollution)in a watershed. Most students, especially younger students, conceptualized a watershed asa human-constructed storage facility, such as a “shed” or “tower,” suggesting that they hadlittle to no understanding of the watershed concept.

Dove, Everett, and Preece (1999) investigated UK students’ understandings of the riverbasin (watershed) concept. They analyzed the drawings (n= 306) of rural 9–11-year-olds,and identified five levels of understanding about rivers. Students’ conceptions ranged froma single river (Levels 1 and 2, 13% of students) to a single river with either a mouth or source(Level 3, 22% of students) to a single river with both a mouth and source (Level 4, 57%of students) to a single river with more fluvial features (Level 5, 4% of students). Of theselevels, only Level 5 reflected a more developed understanding of the watershed concept.Half of the students drew a mountainous terrain, with few drawing an urban environment.Only 7% of the student drawings depicted rain or any other form of precipitation; thus,unlike the students in the Shepardson, Harbor, and Wee (2005) study, these students didnot see the connection between a watershed and the hydrologic cycle.

THEORETICAL AND METHODOLOGICAL FRAMEWORK

A constructivist perspective guided this study. Constructivism, as a research referent,aims to understand the meanings constructed by students participating in context-specificactivities using language (Schwandt, 1994). Central to this study was the written language(words) and symbols (drawings) used by students as part of a watershed task to representand communicate their meaning (Holstein & Gubrium, 1994; Kress, Jewitt, Ogborn, &Tsatsarelis, 2001). These signs and symbols represent the students’ interests, motivation,and what they view as crucial and salient for their purpose in making the sign or symbol(Kress et al., 2001). Students generate the meaning for words, such as watershed, inpart based on their prior experiences and existing concepts (Schollum & Osborne, 1987).These meanings are constructed by students based on an interaction between scientificand everyday concepts. Scientific concepts influence everyday concepts while everydayconcepts influence scientific concepts, and it is this interaction that shapes the meaningsstudents construct, communicate, and represent (Vygotsky, 1991). The meanings inherentin students’ conceptions are contextualized because they represent students’ cognitiveconstructions at a particular point in time (Patton, 2002); that is, they reflect the uniquesocial, educational, and cultural experiences of the students.

Similarly, the authors constructed an understanding of the language and symbols the stu-dents used to represent their conceptions of a watershed—the authors created constructionsabout the students’ constructions. Thus, meanings were constructed by the authors withina sociocultural context. Therefore, the codes and categories constructed by the authors areshaped and colored by their experiences and conceptions of a watershed. Our interpretationsof the students’ responses, then, are simply interpretations grounded in our experiences,conceptions, and perspectives about watersheds that are grounded in both environmentaleducation and the geosciences (Patton, 2002).

This study was descriptive in nature and reflected a cross-age survey (Driver, Leach,Millar, & Scott, 1996), involving the collection of qualitative data (i.e., student written and



drawn responses). This qualitative data was then analyzed for its content in an inductivemanner to identify concepts and patterns in student responses. This content analysis wasfollowed with a statistical analysis to determine the significance in the frequency of the iden-tified student conceptions. The cross-age survey was conducted with limited informationabout the social, cultural, and educational experiences of the students and how these mightinfluence students’ responses. The intent of the authors, however, was not to investigatefactors influencing students’ responses but to explore their conceptions about a specific en-vironmental concept (i.e., watersheds). The benefit of a cross-age survey was that it allowedus to collect data from students with varying degrees of educational experience, therebyproviding us access to a breadth of student conceptions with different degrees of sophistica-tion (Driver et al., 1996). This permitted the characterization of students’ conceptions overdifferent age groups and allowed us to identify trends or patterns in students’ conceptions.

METHOD

Sample

We employed a purposeful sampling strategy, using the classrooms of teachers who hadparticipated in an inquiry-based professional development project (Shepardson et al., 2003).We opted for a large sample size as this provided the advantage of sampling a wide range ofstudents so as to document the similarity, diversity, and/or variation in their conceptions ofa watershed; facilitating the comparison and statistical analysis of the data (Patton, 2002).

The Watershed Task was administered to students in 25 teacher-classrooms at differentgrade levels in various community settings that represented a crosssectional design. A totalof 915 students completed the task. This provided us with a large age range (grades 4through 12) across multiple school settings and increased the heterogeneity of the sample.Geographically, data were obtained from Colorado (5%), Indiana (40%), Kansas (15%),Kentucky (5%), Michigan (10%), Minnesota (10%), Tennessee (10%), and Wisconsin(5%). Several teachers at the middle and high school level administered the watershedtask to multiple classrooms. In these instances, student responses were collapsed into asingle teacher-classroom sample. The 25 teacher-classrooms were distributed as follows:19% upper elementary, 57% middle school, and 24% high school. The classrooms alsorepresented urban schools (16%), suburban schools (24%), and rural schools (60%). Wedid not collect ethnicity or gender data.

The Watershed Task

The Watershed Task was designed as an idea-eliciting task and was based on the inter-views about instances task (Osborne & Freyberg, 1987) and the draw and explain protocol(White & Gunstone, 1992). Drawings elicit students’ conceptions without constraining thestudent to predetermined responses (White & Gunstone, 1992). Furthermore, it providesstudents with a nontraditional, open-ended way in which to express their ideas (Rennie &Jarvis, 1995). The written portion allows students to describe their drawings and clarifiestheir conceptions for the researchers. These written responses also allow the researchers tovalidate meanings constructed from the students’ drawings.

Specifically, written prompts (i.e., “Draw what you think a watershed is” and “Explainthe drawing in your own words”) were used to elicit student responses and these emphasizedthe students’ ideas or concepts. A number of researchers have used such draw-and-explaintasks to elicit students’ ideas about environmental and geoscience phenomena (e.g., Alerby,2000; Anderson & Moss, 1993; Barraza, 1999; Bonnett & Williams, 1998; Payne, 1998;Simmons, 1994).


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The students’ drawings are conceptual visualizations or representations of their under-standings about watersheds that contain a number of individual concepts and, like words,are embodied with meaning (Alerby, 2000; Kress et al., 2001). The students’ drawings,then, are representations of their conceptions (Glynn & Duit, 1995) and “reveal qualitiesof understandings that are hidden from other procedures” (White & Gunstone, 1992,p. 99). Thus, students’ conceptions may be constructed from their graphic representations(Vosniadou & Brewer, 1992).

Data Collection

The Watershed Task was administered to the students during the month of September.Students completed the task during their regularly scheduled science time (elementary)or science class. Each teacher was familiar with the watershed task and its administrationas they had completed the task themselves. The teachers were provided written directiondescribing the procedures for administering the task. The task was administered by theteachers prior to any classroom instruction on the watershed concept. As noted above, itis unknown what formal or informal educational experiences these students had prior tocompleting the Watershed Task.

Data Analysis

Data analysis involved two phases. The first phase involved a content analysis of students’responses resulting in the identification of students’ conceptions, and this process wasinductive in nature. The second phase involved the statistical testing of the identifiedconceptions across classrooms. The chi-square test was used to statistically determine theindependence and goodness-of-fit of students’ conceptions. These two phases of analysisare described in detail below.

Content Analysis. The interpretive nature of the Watershed Task required an inductiveapproach; that is, instead of searching for predetermined patterns, themes were allowed toemerge from the data as the authors constructed meaning from students’ responses(Patton, 2002). The following process details the analytical procedure described by Rubinand Rubin (1995). From the first reading of the Watershed Task, core concepts (codes) wereidentified. These initial codes were revised after a second reading. Descriptive themes werethen constructed using the codes across different grade levels, geographical locations, andcommunity settings. Codes with common/overlapping themes were subsequently placedinto categories that reflected the students’ conceptions. Each researcher independentlygrouped the codes into individual categories. From these individual category matrices, weconstructed a group-consensus category matrix that linked each code to a category(Erickson, 1986) and that reflected the final categories of student conceptions about wa-tersheds. This enabled us to organize and check the data for saturation of categories andto eliminate redundant categories (Erickson, 1986; Lincoln & Guba, 1985). This processof independently constructing categories and then reaching group consensus provided adegree of triangulation, reducing the influence of bias and subjectivity, and increasing thevalidity of our analysis and interpretation of the results (Patton, 2002; Strauss, 1987).

The data were also analyzed for confirming and discrepant situations in order to enhancethe authenticity of the interpretations and the credibility of the findings (Patton, 2002).Students’ conceptions were triangulated across different grade levels, geographic regions,and community settings. To ensure consistency in coding, an interrater reliability coefficientwas calculated by comparing the authors’ coding of 10 randomly selected Watershed Tasks.



The interrater reliability coefficient for the task was 0.90. Coding was monitored throughoutto ensure consistency and reliability.

Statistical Analysis. We employed the chi-square test to determine statistical signifi-cance of the frequency of the identified conceptions across all 25 teacher-classrooms. Wecompared the frequency of the conceptions across classrooms (teachers) to determine thestability of the conceptions using a 25 × 4 matrix (classroom × conception). This initialchi-square test allowed us to examine the validity of the identified conceptions based onstatistical significance; that is, our interpretations of students’ conceptions were reflectiveof the data if there was no significant difference in the frequencies of the conceptions acrossclassrooms.

Although there should be no significant difference in the overall frequencies of theconceptions, it is possible that the frequencies may differ by grade level or communitysetting. Thus, to answer our second research question we conducted a series of chi-squaretests partitioning the data by grade level (i.e., upper elementary, middle school, and highschool) and by community setting (i.e., rural, suburban, urban).

RESULTS

We first present the results of our inductive analysis, identifying the four emergent cate-gories that reflected the students’ conceptions. Next, we report the results of our statisticalanalysis of the distribution of students’ conceptions across different data partitions: gradelevel and community setting.

Students’ Conceptions of a Watershed

From the inductive analysis, we identified 44 codes (concepts) that reflected the students’responses on the Watershed Task. These codes were grouped based on themes that reflectedfour categories of student conceptions about watersheds:

• Conception 1: Watershed as a natural and dynamic process consisting of a developedhydrologic cycle.

• Conception 2: Watershed as a natural process containing elements of the hydrologiccycle.

• Conception 3: Watershed as the natural storage of water (i.e., bodies of water—lakeor pond).

• Conception 4: Watershed as a human-built facility for storing water (e.g., water storedin a “shed” or “tower”).

Each of the conceptions, with the exception of Conception 4, depicts a watershed as anatural environment involving a natural process based on the hydrologic cycle. The com-plexity of the hydrologic cycle varies across conceptions, with Conception 1 representingthe most complete and complex view of the hydrologic cycle. In addition, the task elicitedthe importance of topography, relief, and elevation, in determining a watershed. Concep-tions 1 and 2 emphasized mountainous or hilly terrain, topography with high relief andelevation. Conceptions 1 and 2 also included a single river or stream, whereas Conception3 centered on a lake or pond as a site of water storage. Thus, students’ conceptions wereprimarily built upon topography and the hydrologic cycle. Each of these conceptions isexplained below and depicted in Table 1.


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TABLE 1Elements of Each Conception

Conceptions

Elements Conception 1 Conception 2 Conception 3 Conception 4

Human storage XBuilt environment XNatural environment X X XNatural process X X XNatural storage X X XTopography X XWater transformation X XSingle river X XGroundwater/runoff X

Conception 1: Watershed As a Natural and Dynamic Process Involving a DevelopedHydrologic Cycle (Figure 1). By developed hydrologic cycle, we mean that students rep-resented runoff or groundwater in addition to evaporation, condensation, and precipitation.For these students, a watershed consisted of a single stream that flowed relative to the topog-raphy of a landform (e.g., mountain or hill). Precipitation (e.g., rain or snow) flowed off theland and into the stream. The stream flowed into a lake or pond “or even an ocean.” Someof the precipitation percolates into the ground. Topography of high relief and elevation wascentral to this conception, as was the hydrologic cycle.

A few students (Figure 2), however, represented a watershed as a river system thatcontained a “main river” and “tributary” and “runoff” from hills. As shown in Figure 2,the watershed is the “place where water (runoff, ground water, rivers) ‘drains.’ All waterin an area drains here.” These students focused on the river system and the movement ofwater and less on the landforms. Again, topography of high relief and elevation is evident.We should note that this conception does not reflect a developed conceptual model of awatershed, but simply a developed view of the hydrologic cycle.

Conception 2: Watershed As a Natural Process Containing Elements of the Hydro-logic Cycle (Figure 3). What differentiates this conception from Conception 1 is theemphasis on the hydrologic cycle as the transformation and cycling of water—evaporation,condensation, and precipitation. Students do not include groundwater or runoff as partof their response. Water is stored, usually in a pond or lake, and is evaporated and thenit rains “recycling” the water. As the student says, “Water is stored and then evaporates& recycles.” Students’ written explanations reinforce the connections drawn between thehydrologic cycle and topography (Figure 4).

Conception 3: Watershed As the Natural Storage of Water. Student responses in thiscategory, like the one shown in Figure 5, emphasized the storage of water in lakes or ponds,often between or in mountains: “A big lake in between Mountains.” The water is transportedto the lake by a river or stream. The hydrologic cycle is not represented or identified as thewater source. Similarly, as shown in Figure 6, student responses often represented a lakeor pond as the watershed: “an area of water that is surrounded by trees and grass.” In allstudent responses, the emphasis was on the natural storage of water. Topography was not



Figure 1. Student example, Conception 1: A mountainous watershed with a developed hydrologic cycle. [Colorfigure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

critical to this conception; that is, student responses included lakes and ponds in areas ofno relief (see Figure 6).

Conception 4. In this case, a watershed is viewed as a human-built facility for storingwater. Student responses for this category represented human-built facilities (e.g., shedsand towers) for storing water as shown in Figure 7. In addition, the water being stored inthese facilities is intended to be used in times of need or for emergencies. As the studentwrites, “A shed full of water just for holding: it can be used for water shortages” (Figure 7).


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Figure 2. Student example, Conception 1: A river system with a developed hydrologic cycle.

Another student writes that the watershed is “a giant container underground that collectsrainwater and pumps it to pipes that hold [water] until we need it” (Figure 8). Unlike theother conceptions, students who reflected this group situated the water storage facilities innonnatural areas—towns and cities (Figure 9).

Descriptive Statistics. The percentages for each conception are shown in Figure 10.The dominant conception elicited was Conception 4: a literal representation of the words“water” and “shed” in combination. This conception reflects a word-meaning associationwherein students’ prior experiences and knowledge about the terms “water” and “shed”



Figure 3. Student example, Conception 2: A watershed containing elements of the hydrologic cycle.

TABLE 2Chi-Square Results, Conceptions by Grade Level and Community Setting

Conception 1: Conception 2:Natural Natural Conception 3: Conception 4:

Dynamic– Dynamic– Natural Water Human WaterDeveloped Elements Storage Storage

Grade level (2 df ) χ2 = 6.47 χ2 = 2.32 χ2 = 1.46 χ2 = 5.36p = .039 p = .313 p = .481 p = .069

Community setting χ2 = 5.08 χ2 = 3.00 χ2 = 9.42 χ2 = 4.17(2 df ) p = .079 p = .223 p = .009 p = .124


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Figure 4. Student example, Conception 2: A watershed containing elements of the hydrologic cycle andtopography. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

are used to make meaning of the watershed concept. It reflects the storage of water; thatis, water is stored in a “shed” or “tower,” and this conception of a watershed accounted for46% (n = 429) of the student responses. Only 29% (n = 265) of the students conceptualizeda watershed as a natural and dynamic process that incorporated a developed view of thehydrologic cycle (Conception 1). These students not only viewed the dynamic nature ofa watershed, water running off of land surfaces into lakes and streams or percolating intothe ground, but also how water evaporates from surface water, condenses, and returns tothe watershed as precipitation. Of the remaining students, 7% (n = 64) conceptualized a



Figure 5. Student example, Conception 3: A watershed as the natural storage of water.

watershed as a natural environment with elements of the hydrologic cycle (e.g., evaporation,precipitation, condensation) and 18% (n= 165) conceptualized a watershed as a naturalenvironment for water storage (Conception 3).

Chi-Square Statistics. The comparison of the frequency of the students’ conceptions byclassroom showed no significant difference: χ2 (72 df ) = 2.23, p = .999. This supports theplausibility of the existence of the four conceptions of a watershed; that is, the frequenciesof the conceptions were consistent across all 25 teacher-classrooms.


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Figure 6. Student example, Conception 3: A watershed as the natural storage of water.

Watershed Conceptions by Grade Level and Community Setting

The percentage of each conception by grade level and community setting is shown inFigures 11 and 12. Using a traditional 95% significance level cutoff, the only statisticallysignificant differences were grade level by Conception 1, a developed conceptualization ofa watershed, and community setting by Conception 3, a watershed as a natural but staticprocess (Table 2). A greater percentage of upper elementary (38%) and middle school (36%)students conceptualized a watershed as a dynamic process incorporating a developed viewof the hydrologic cycle compared to the percentage of high school (16%) students. Thismay reflect the fact that the hydrologic cycle tends to be taught at the upper elementary and



Figure 7. Student example, Conception 4: A watershed as a human-built facility for storing water. [Color figurecan be viewed in the online issue, which is available at www.interscience.wiley.com.]

middle school levels. Rural students (38%) were also more likely to hold a well-developedconception of the hydrologic cycle compared to suburban (24%) and urban (1%) students.

High school (69%) students were more likely than upper elementary (30%) and middleschool (53%) students to use the words “water” and “shed” to represent a watershed(Conception 4). These findings suggest that high school students perhaps realize that thehydrologic cycle is not the same as a watershed yet because they do not know what awatershed is or have not been exposed to the watershed concept, they represent the conceptby dividing the word “watershed” into the words “water” and “shed.” They tied the words


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to concrete objects they were familiar with; the meaning-making process was shaped by theeveryday concepts of “water” and “shed.” Thus, everyday language guided these students’conceptual constructions (Duit, 1991) and how they represented their conception of awatershed as human water storage.

Urban (91%) students were more likely than rural (40%) and suburban (67%) studentsto literally represent the word “watershed.” This may reflect the urban landscape (whererunoff often disappears quickly into storm sewer systems rather than flowing over land tostreams) and the fact that water towers are more likely to be visible and used as a watersupply than in rural areas. Conception 3, a watershed as a natural storage facility, was morelikely to be held by rural (20%) students than urban (8%) and suburban (8%) students. This




too may reflect the local experience and landscape, where in many agricultural areas “farmponds” are common features used to store surface water.

DISCUSSION

It is important to stress that the conceptions of a watershed described in this articlereflect the sample as a whole and not individual students. It is possible that an individualstudent, under a different context, might convey a different conception. The categories arean attempt to characterize the different conceptualizations students hold about watershedsand to summarize these in such a way as to inform practice and to further our understanding


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46%

18%

7%

29%Human waterstorage

Natural waterstorage

Hydrologiccycle

Hydrologiccycle/runoff

Figure 10. Percentage of each conception. [Color figure can be viewed in the online issue, which is available atwww.interscience.wiley.com.]

0

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70

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C1 C2 C3 C4

Conceptions

Upper El

Middle Sch

HS

Figure 11 KeyC1: Conception 1 C2: Conception 2 C3: Conception 3 C4: Conception 4

Figure 11. Percentage of conceptions by grade level. [Color figure can be viewed in the online issue, which isavailable at www.interscience.wiley.com.]

0102030405060708090

Per

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RuralSuburbanUrban

Figure 12 KeyC1: Conception 1 C2: Conception 2 C3: Conception 3 C4: Conception 4

Figure 12. Percentage of conceptions by community setting. [Color figure can be viewed in the online issue,which is available at www.interscience.wiley.com.]



about how students make meaning of the natural world. Furthermore, the categories aremeant to distinguish the varied ways in which students conceptualize a watershed.

Although the watershed concept provides students with a unique opportunity to learnabout natural systems (Haury, 2000), these students primarily conceptualized a watershedas an area of land with high relief and elevation where water is cycled, and stored or trans-ported. The spatial boundaries of the watershed were not identified. Watershed hydrologywas restricted to precipitation, evaporation, and condensation for most students. In otherwords, the students were focused on the cycling of water between the land surface and theatmosphere, rather than water movement across the land and in streams and rivers (trans-portation). Only 29% of the students incorporated runoff or groundwater, a more developedconception. Watershed structure for most students was equated to single streams and rivers;few students identified tributaries or represented a river system. Watershed function waslimited to the transport and storage of water, and in most cases storage involved a singlelake or pond. Students’ conceptions emphasized the transport and storage and cycling andtransformation of water. These watershed functions were not applied to sediments, nutri-ents, pollutants, or other materials within the watershed, a critical link when watershedconcepts are being used as a foundation for understanding how to prevent nonpoint sourcepollution.

Biology (e.g., vegetation, animal life) was rarely identified, except for esthetic purposes oras part of the environment (i.e., mountains have trees). The biological component contributessignificantly to the quality of the watershed. For example, if the biology of the watershedis agricultural, pasture, and cattle, the biology determines the nature and type of runoff andits impact on water quality. A cattle pasture may result in more nitrates and phosphates orE. coli entering a stream or lake than forested land. Beyond precipitation (e.g., rain andsnow), the climate of the watershed also needs to be considered. For example, the climatedetermines the form and amount of precipitation, which influences how much water runsoff the land and how and if water is stored.

Students’ Conceptions and the Science Curriculum

The mountainous watersheds drawn by many students reflect the prototypical watershedexample shown in many textbooks and other educational resources, but do not resemblethe topography of watersheds in Midwestern states where the vast majority of the studentsin this study live. This suggests that students may not connect the watershed conceptto their everyday world, where they live, play, and go to school (Patterson & Harbor,2005; Shepardson, Harbor, & Wee, 2005). In addition, these students’ conceptions aboutwatersheds largely focused on natural landscapes rather than the urban- or human-managedlandscapes most of them live in, with the exception of those students who saw watersheds asa human-built storage facility. Thus, these students did not display the necessary conceptualknowledge of the watershed concept to understand nonpoint source pollution. That is,they did not understand that water transported across the land and through surface waterdistributes the effects of human activities throughout a watershed. In essence, these studentsdid not display an understanding of humans as part of a watershed or of concepts that wouldlead to an understanding of how human activity impacts a watershed and water quality.

The fact that poorly developed conceptions about watersheds are retained from elemen-tary through high school suggests that education is contributing little to the developmentof a citizenry that is knowledgeable about watersheds. Thus, there is a need for schoolsto develop the watershed concept within curricular frameworks (Haury, 2000). Designinga curriculum based on students’ conceptions that builds toward a scientific perspective isessential (NRC, 1996) if students are to become more knowledgeable about water-related


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issues and environmental health in general. Educators, administrators, and legislators woulddo well to heed the notion that “central ideas related to health, populations, resources andenvironments provide the foundation for students’ eventual understanding and actions ascitizens” (NRC, 1996, p. 138).

Effective learning experiences require a curriculum that is sequenced in a way that movesstudents toward scientific understanding—curricular continuity (Driver et al., 1994). Thefindings suggest that elementary and middle school students have a rudimentary understand-ing of watersheds based on topography—high relief and elevation—and the hydrologic cy-cle. This likely stems from the students’ educational experiences with the hydrologic cycle,particularly in cases where teachers themselves are unfamiliar with the watershed con-cept and assume (wrongly) that students will derive some understanding about watershedssimply by learning about the hydrologic cycle. These experiences often involve visualsthat portray precipitation falling on mountains and other landforms with high relief andelevation, where the water is collected or stored in a lake or pond from which it evaporates.Thus, it seems that curriculum would be better designed to incorporate the hydrologic cyclewithin the context of the watershed concept. Based on the findings from this study and ourconceptual model of watersheds (Figure 13), the following concepts need to be developedin order to enhance students’ conceptualization of watersheds:

• When rain falls on the land, or snow melts, some of the water soaks in to the ground,some of it evaporates back in to the atmosphere, and some of it flows over the land ina down slope direction, often toward streams, rivers, lakes, or wetlands. A watershedis the land area that provides runoff that feeds particular rivers, streams, lakes, ponds,or wetlands; that is, a watershed has a structure (i.e., flowing and still water).

• Every place on land is a part of a watershed, including the places where we live,work, play, and go to school.

• Smaller streams flow into larger rivers forming a river system, a network of tributariesthat flow into a major river, which drains water from the land within the watershed.

• Watershed boundaries are defined based on topography. Topographic divides deter-mine the direction water flows and any and every point on a stream, river, or body ofwater has a watershed associated with it.

• The earth’s surface consists of numerous nested and joining watersheds that drain intolakes or oceans. These subwatersheds may be further divided into smaller watersheds.

• Sediments, nutrients, and other substances and contaminants on land are transportedinto the stream through runoff and temporarily stored before being transported

TABLE 3The Relationship Between the NRC System Standards and the WatershedConcept

NRC System Concepts Watershed ConceptsStructure Flowing and/or still water: rivers, streams, lakes, ponds,

wetlandsFunction Transportation and storage and cycling and transformation of

water, nutrients, sediments, and pollutantsFeedback/equilibrium Biogeochemical cycles, water velocity, organismsBoundaries Topography, relief and elevation, landformsComponents Physical: climate, geomorphology, hydrology Biological: plants

and animals (including humans)Resources

(inputs/outputs)Water, nutrients, sediments, pollutants, energy (e.g., sun,

kinetic—moving water)



Watershed

Defined by elevation and relief

Structure

Consists of

Flowing water: streams, rivers

Still water: lakes, wetlands

Physical components

Climate

Hydrology

Geomorphology

Biological components

Plants

Animals

Humans

Changed by

Natural processes Human activity

Functions to

Transport water and materials

Store water and materials

Cycle water and materials

Transform water and materials

Polluted by

Point source Nonpoint source Biological, organic, inorganic, thermal

Figure 13. A watershed model.


WATERSHED 575

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through the watershed by the river system and into joining watersheds. The contam-inants transported off the land area and through the river system are often referred toas nonpoint source pollution: fertilizer and pesticide runoff, for example.

• Sediments, nutrients, and other substances are transformed and cycled within awatershed (e.g., nitrogen and carbon cycles).

• Pollutants may be organic, inorganic, toxic, thermal, or biological. Zebra musselsare a biologic pollutant—an invasive species.

• Watersheds consist of physical and biological components that influence the qualityof the watershed and make each watershed unique. For example, a watershed in theArizona desert is physically and biologically different than a watershed in Indiana.

• Water, nutrients, pollutants, and the sun serve as energy resources within the water-shed. For example, the sun’s energy warms the water within a stream or pond anddrives the hydrologic cycle.

• Watersheds are constantly changing as a result of natural and anthropocentric pro-cesses, which often interact. These changes may impact the structure, function, andcomponents of a watershed.

The Relationship Between the NRC Standardsand the Watershed Concept

The watershed concept as a curricular theme provides schools an excellent opportunity todevelop an interdisciplinary and thematic curriculum where students learn about their localenvironment. As a natural system, watersheds have boundaries, components, resources(inputs and outputs), and feedback processes (NRC, 1996). The relationship between theNRC (1996) systems concept and the watershed concept is shown in Table 3.

This interdisciplinary nature of the watershed concept promotes curricular linkages withthe NRC (1996) Science Education Standards as shown in Table 4. Although the tablepresents a condensed version of the K-12 science standards, it demonstrates that the de-velopment of a curriculum grounded in the watershed concept can provide opportunitiesfor students and teachers to explore and analyze the natural world from a systems-basedperspective rather than in isolated segments. Thinking about watersheds and other naturalphenomena in such a holistic manner creates a meaningful context for learning and do-ing science because it requires that students use and apply concepts from other sciencedisciplines.

CONCLUSION

Students in this study primarily conceptualized a watershed as an area of land with highrelief and elevation where water is cycled and stored or transported. Watershed hydrologywas restricted to precipitation, evaporation, and condensation for most students. In otherwords, these students focused on the cycling (transformation) of water rather than thetransportation of water between the land surface and water bodies such as streams and rivers.The purpose of this study was to elucidate students’ conceptions of a watershed; it was not anattempt to identify or articulate the origin or development of students’ conceptualizations.Thus, there is a need for future research to determine the role of students’ experienceand education in shaping the development of their conceptions. Do individuals developdifferent conceptions over time? How does social interaction among peers, teachers, andparents influence the development of a student’s conceptualization of a watershed? Althoughthis study separated students’ conceptions by grade level and community setting, there isa need to investigate students’ conceptions by gender, age, culture, and socioeconomic


WATERSHED 577

conditions. Longitudinal studies of students’ developing conceptions would also be usefulin determining the impact of experience and schooling on students’ conceptualizationof watersheds. Finally, there is a need to understand the relationship between students’conceptions and their environmental behaviors and decision making.

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