Incorporating student-centered approaches into catchment hydrology teaching: a review and synthesis

As hydrologists confront the future of water resources on a globalized, resource-scarce and humanimpacted planet, the educational preparation of future generations of water scientists becomes increasingly important. Although hydrology inherits a tradition of teacher-centered direct instruction – based on lecture, reading and assignment formats – a growing body of knowledge derived from engineering education research suggests that modifications to these methods could firstly improve the quality of instruction from a student perspective, and secondly contribute to better professional preparation of hydrologists, in terms of their abilities to transfer knowledge to new contexts, to frame and solve novel problems, and to work collaboratively in uncertain environments. Here we review the theoretical background and empirical literature relating to adopting student-centered and inductive models of teaching and learning. Models of student-centered learning and their applications in engineering education are introduced by outlining the approaches used by several of the authors to introduce student-centered and inductive educational strategies into their university classrooms. Finally, the relative novelty of research on engineering instruction in general and hydrology in particular creates opportunities for new partnerships between education researchers and hydrologists to explore the discipline-specific needs of hydrology students and develop new approaches for instruction and professional preparation of hydrologists. 1 Introduction There is an increasing need to understand the dynamics of water resources as key determinants of development, human and environmental health, and conflict and sustainability (Gleick and Palaniappan, 2010; Postel and Wolf, 2001; United Nations Development Program, 2011). The context of the global water crisis provides a strong motivation for universities to train cohorts of hydrological professionals who can provide expertise in interpreting, predicting and managing the dynamics of water in the 21st century. Sustainable management of water resources is challenging for many reasons: the global nature of water scarcity, the complex interconnections between hydrologic dynamics and a myriad of physical, biological, social and economic processes that take place in catchments (Rockstrom et al., 2009; Vorosmarty et al., 2010; Crutzen and Stoemer, 2000), and the difficulties that global changes in climate and land use pose for prediction (Milly et al., 2008). In this context, the hydrologic community needs to critically appraise the teaching of hydrology, not only in terms of the content of hydrologic courses, but also in terms of the way that the subject is taught as it impacts the professional development of future hydrologists (Uhlenbrook and de Jong, 2012; Wagener et al., 2012). The science of education research expanded significantly during the latter half of the 20th century (Piaget, 1954; Smock, 1981; Zimmerman, 1981), with a specific focus on engineering education emerging in the past 10 yr (Shulman, Published by Copernicus Publications on behalf of the European Geosciences Union. 3264 S. E. Thompson et al.: Incorporating student-centered approaches into catchment hydrology teaching 2005). This body of research into how students learn, and into the kinds of educational efforts that can promote desirable educational outcomes offers a valuable resource to hydrologists as they confront the challenge of evaluating and reforming hydrology education. The revolution in hydrology teaching demanded by practitioners and commentators is broadly reflected in discussions surrounding the future of science and engineering education (Rugarcia et al., 2000). The aim of this paper is to provide a summary of some of the theoretical developments in educational research that are pertinent to the teaching of hydrology, to illustrate these concepts with hydrological examples, and to review our attempts to apply these developments in our own classrooms and within targeted hydrology summer schools. Despite the expansion of engineering education research, there remains a dearth of research specifically targeting hydrology education, meaning that we have relied largely on anecdotal accounts when discussing hydrological examples, and on examples from the broader literature to provide empirical data. The only clear way to overcome these limitations is to engage upon a program of educational research within hydrology, and the paper concludes with a discussion of where the opportunities for such research might lie. To avoid confusion between different disciplinary foci within hydrology, the paper primarily addresses educational issues associated with teaching catchment hydrology at an upper undergraduate–graduate level. The arguments may therefore reflect the perspectives of catchment hydrologists, but we hope that they will prove relevant to teaching and learning across multiple hydrological sub-disciplines. 2 Hydrology graduates: traditional requirements and modern challenges Lying at the interfaces of many disciplines and perspectives, there are multiple dimensions to knowing and understanding catchment hydrology (Wagener et al., 2010; Vogel, 2011). The working definition of a catchment hydrologist for our purposes is someone who is engaged in the quantitative study of the terrestrial water cycle at the scale of individual catchments (Wagener et al., 2004). Two opposing approaches to conceiving catchment hydrology can be outlined: the first based on the application of fundamental physical laws – specifically the conservation of energy, mass and momentum – within boundary conditions set by the natural environment. Dooge (1981) referred to this reductionist, process-based approach as providing the “internal descriptions” of the catchment. Alternatively, hydrologists may study the dynamics of the overall catchment system without references to the detailed structure of its components. The nature of the functioning of the system is inferred from the input and output observations. Despite the process complexity at small scales, catchment responses at large scale are often rather simple (Sivapalan, 2003). Dooge (1981) calls this macroscopic approach the “external description” of the catchment. Both approaches have strengths and limitations: the internal description perspective is challenging to apply at large spatial scales, because natural systems are heterogeneous, contain complex forms of spatial and temporal organization, and are usually impossible to completely observe; while methods based on external descriptions are difficult to extrapolate to different places or different times. There are many traditional tools that are used to make hydrological predictions from both perspectives (e.g., flood frequency analysis, rational method, US-SCS curve numbers, unit hydrograph approaches, Green and Ampt infiltration equation). These tools have strengths and are often embedded in standard approaches for hydrological prediction, but are also subject to limitations (Wagener, 2007; Beven, 1993), which may be exaggerated under scenarios of land use and climate change (Sivapalan et al., 2003; Milly et al., 2008). As human activity increasingly drives hydrological dynamics, hydrologists are also forced to confront the interaction of natural and engineered systems, and of water resource management decisions on the dynamics of the hydrological cycle, in effect expanding the domain of the discipline as a whole (Gupta et al., 2000). Numerous calls have been made to the hydrology community to alter its perspectives from a “business as usual” model to one which can respond to the challenges posed by global change (Gupta et al., 2000; Dooge, 1986, 1988; Torgersen, 2006; Hooper, 2009; Uhlenbrook and de Jong, 2012; Wagener et al., 2012). This emerging perspective in many ways requires a unification of the internal and external approaches. It challenges students to generate new knowledge, expertise and experiences that represent a synthesis of process knowledge and knowledge gained from interpreting data relating to hydrological response directly at the catchment scale. Hydrology education must provide students with the ability to approach the hydrological prediction problem from both perspectives, and provide experiences to gain the depth of understanding to synthesize the knowledge derived from each one. Comprehending this level of complexity, and the duality of the ways to conceptualize hydrological processes, requires higher-order, reflective, metacognitive and critical thinking skills – skills that are increasingly identified across multiple scientific and engineering disciplines as the core elements of professional competence (Lenschow, 1998). Future hydrological scenarios are characterized by uncertainty, associated with non-stationarity, human influences, climate change and an increased appreciation of the nonlocal and complex interactions between hydrological processes and other environmental processes. Future hydrologists must undertake their work in the face of this uncertainty. In these contexts, scientists who make decisions based on didactic rules are unlikely to produce useful contributions. Interpreting data, formulating, developing and testing conceptual models, and critically evaluating ideas, however, will be essential, as will the ability to work across disciplines and Hydrol. Earth Syst. Sci., 16, 3263–3278, 2012 www.hydrol-earth-syst-sci.net/16/3263/2012/ S. E. Thompson et al.: Incorporating student-centered approaches into catchment hydrology teaching 3265 across geographic areas (Gupta et al., 2000; Dooge, 1986, 1988; Torgersen, 2006; Hooper, 2009). Core elements of such interdisciplinarity are increasingly reflected in the formal curricula for hydrological specialists – hydroinformaticians for instance are expected to have an education that spans “physics, mathematics, ecology, geography and computer and software engineering” (Popescu et al., 2012). The challenge for the modern education of hydrologists, then, is to firstly provide graduates with a strong understanding of the fundamental theories, tools, methods and approaches of contemporary hydrology, and also, hopefully, with positive feelings about hydrology (educational outcomes in the affective or emotional domain) (Bloom, 1956). Beyond knowledge, however, hydrology education is now challenged to prepare creative graduates with skills in critical thinking, collaboration, interdisciplinary communication, with the intellectual confidence to proceed in an uncertain environment, and with an ethical framework to address complex issues responsibly (Stouffer et al., 2004). Not only, therefore, do we need to teach hydrologists well, and to leave them with positive responses to hydrology as a discipline; but we need to adopt ways of teaching that can foster these intangible skills. The lecture and homework-problem based teaching that applies material covered in class and emphasizes getting the “right answer” (Mills and Treagust, 2003), typical of most hydrology courses (Aghakouchak and Habib, 2010; Elshorbagy, 2005; Mohtar and Engel, 2000), seems almost antithetical to the implicit skills hydrology graduates need, and often fails to provide opportunities for students to exercise and develop skills in problem solving, writing or teamwork (Woods et al., 2000). Education research suggests that didactic, “chalk and talk” approaches to teaching are often ineffective helping students develop an appropriate understanding of content (Goris and Dyrenfurth, 2012; Duit, 2004). To understand this point of view, it is necessary to review educational theory. 3 Framework, vocabulary, and an overview of educational theory 3.1 The four components of education There are four essential elements in education – the learner; the subject matter and syllabus, which comprises the skills and knowledge the learner is to master; the methods of teaching and learning activities used to bridge the two, known as the pedagogy; and the assessment used to measure outcomes of learning and to guide ongoing pedagogical activities (Shuell, 1986; Smith et al., 2005; Pellegrino, 2006). To be effective, a pedagogical method must be appropriate to both the nature of the learner and the content being covered (Bransford et al., 2004; Svinicki, 2004; Catalano and Catalano, 1999). While we recognize the importance of the assessment of learning outcomes, this discussion focuses on the intersection of the learner, the content and the pedagogy. 3.2 Pedagogical content knowledge What enables a good teacher to teach well? It is clearly not just an expert command of the subject matter – we have all known experts who teach poorly. Similarly, it must be more than mastering pedagogical skills: we would not expect an English professor to teach hydrology well, no matter how good an English teacher they were. Good teachers, therefore, must have knowledge about how to teach particular kinds of subject matter to facilitate learning (Bodner, 1986; Ward and Bodner, 1993). This understanding of how to link pedagogy with the subject matter is known as Pedagogical Content Knowledge, or PCK. PCK tends to be an idiosyncratic notion of what is appropriate to teach, at what point, through what method. It is content specific: in the context of catchment hydrology, PCK relates to the understanding of which concepts are difficult to understand, and why, and how teaching strategies can explicitly cater to those challenges (Shulman, 1986; Shulman and Shulman, 2007). As teachers develop their expertise, their PCK will also grow and develop. PCK can have many forms, but might be best defined as “the most powerful analogies, illustrations, examples, explanations, and demonstrationsin a word, the ways of representing and formulating the subject that makes it comprehensible for others” (Berry et al., 2008). To illustrate the concept of PCK, consider the use of the “leaky-bucket” or “flowerpot” analogy of a catchment, illustrated in Fig. 1. The leaky-bucket or flowerpot analogy invites students to think about a catchment as a more elaborate form of a flowerpot. Water is introduced into the flowerpot system by irrigation or rainfall, is partitioned into infiltrated water and runoff at the surface, is transpired by the plants in the flower pot, and drains from the flower pot as it reaches its base (the “leaks” in the “leaky bucket”). Like real catchments, the flowerpot contains soil, water and vegetation, and represents a fluctuating, vertically inhomogeneous moisture store. Many of the simple process descriptions that can be applied at catchment scales are made intelligible by developing “leaky-bucket” models of the flowerpot. Why is the flowerpot or leaky bucket an effective element of PCK? It has several strong points: it draws on student familiarity with potted plants, it allows simple experiments to be performed, the processes in the flowerpot bear reasonably good correspondence to those in real catchments, and the mathematical and theoretical descriptions derived from the model form a reasonable bridge to more complex process descriptions, or to forming scaled-up models that are suitable for representing catchment processes. As with all conceptual models of real world processes, it may result in the generation of misconceptions (for instance it is a poor representation of heterogeneity and of the relative scale of vegetation www.hydrol-earth-syst-sci.net/16/3263/2012/ Hydrol. Earth Syst. Sci., 16, 3263–3278, 2012 3266 S. E. Thompson et al.: Incorporating student-centered approaches into catchment hydrology teaching Infiltra(on / “Overland flow” par((oning Rainfall (P) Transpira(on/ Evapora(on (ET) Deep drainage / OuAlow (Q) Storage (S) S = h x n Depth of saturated zone (h) Soil proper(es e.g. porosity (n) “Flowerpot” Runoff Model: Q = -­‐k S dS/dt = P – ET – Q Fig. 1. Cartoon illustration of the flowerpot analogy for a catchment used in teaching catchment hydrologists. Containing vegetation, a root zone, a vadose zone, a saturated zone and soil; and modeling processes of rainfall, infiltration, surface flow partitioning, drainage, outflow, evapotranspiration and water storage in the soil, the flowerpot is an effective example of PCK commonly employed by catchment hydrologists. By employing simple parameterizations of the fluxes and a water balance over the flowerpot, a simple runoff model can be made and explored. to catchment size). Effective PCK in this case would also involve highlighting the ways in which a flowerpot’s water balance behavior differs from reality, and the limitations of the usefulness of thinking about catchments in this way. 3.3 Varying teaching and PCK to reflect the way that people learn Because PCK arises from an idiosyncratic relationship between instructor, content and the context of the students, there is never only a single “right” way to teach particular content. In fact, research on the development of disciplinary specific expertise has demonstrated that the suitability of instructional methods differs according to the nature of the discipline, concepts and topics taught within the discipline (Donald, 2002; Clough and Kauffman, 1999). However, higher quality teaching, and thus good PCK, likely arises when the pedagogy and the content both work together to enhance student learning. To evaluate or design teaching approaches, it is therefore important to understand how students learn. There are two broad kinds of learning that hydrology students will be engaged with – the learning of facts and principles, and the learning of skills and procedures (Svinicki, 2004). Both are important for catchment hydrologists; however, there is less controversy over procedural learning. There is a general consensus that procedures are largely learned through the observation of others, practice, trial and error (Bandura, 1975, 1986). As illustrated in cartoon form in Fig. 2, however, there are several theories regarding how facts and principles are learned. Information processing theories focus upon how information is communicated to learners and is transformed into knowledge (Svinicki, 2004; Shuell, 1986). This theory proposes that a learner receives information through their senses (e.g., by reading, listening, touching, etc.), which is transmitted into their long-term memory. Information processing suggests that the quality of learning is primarily a function of the quality of the information presented by the instructor. These theories are helpful in explaining common observations of students, for instance “information overload”, unconscious selection of input stimuli, and reduction of knowledge to rote memory (Johnstone, 1997). While information processing theories explain how learners deal with sensory stimuli in the classroom, the dominant theory regarding the transformation of these stimuli into knowledge is now constructivism. Constructivism posits that information is taken in from the environment through the senses and selectively stored in working memory. Learners then make connections between the new information and their prior knowledge, and memories. This process results in the “construction” of new understanding or conceptualizations, which are stored in the longterm memory. Learners therefore play an active role in determining what is learned from particular information sources. Knowledge is constructed in the mind of the learner, rather than being imparted by the teacher and absorbed directly by the student (Bodner, 1986; Smock, 1981). Constructivism implies that new knowledge is evaluated, manipulated, and connected using prior knowledge, preconceptions, values, and beliefs in order to make sense of experiences (Piaget, 1954; Smock, 1981; Zimmerman, 1981; Bodner, 1986). Prior knowledge is not necessarily derived from the classroom, and may reflect self-consistent mental models of the natural world derived from students’ previous experience. Even where these mental models are incompatible with scientific theory, they may prove very resilient. Understanding and working with these prior conceptions thus becomes a core challenge for teachers (Ward and Bodner, 1993). A more recent theory argues that perception and long term memory are socially constructed by a group of learners through a process of discussion and collaboration, a theory known as socioconstructivism (Greeno et al., 1996). Socio-constructivism helps explain the empirical findings that student learning Hydrol. Earth Syst. Sci., 16, 3263–3278, 2012 www.hydrol-earth-syst-sci.net/16/3263/2012/ S. E. Thompson et al.: Incorporating student-centered approaches into catchment hydrology teaching 3267 Didac&c “Chalk-­‐and-­‐Talk” approach Informa&on Processing α β = γ Percep+on filter Working memory Long-­‐term memory Construc&vism