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Monday, February 21, 2022

Computer-supported collaborative learning

From Wikipedia, the free encyclopedia

Computer-supported collaborative learning (CSCL) is a pedagogical approach wherein learning takes place via social interaction using a computer or through the Internet. This kind of learning is characterized by the sharing and construction of knowledge among participants using technology as their primary means of communication or as a common resource. CSCL can be implemented in online and classroom learning environments and can take place synchronously or asynchronously.

The study of computer-supported collaborative learning draws on a number of academic disciplines, including instructional technology, educational psychology, sociology, cognitive psychology, and social psychology. It is related to collaborative learning and computer supported cooperative work (CSCW).

History

Interactive computing technology was primarily conceived by academics, but the use of technology in education has historically been defined by contemporary research trends. The earliest instances of software in instruction drilled students using the behaviorist method that was popular throughout the mid-twentieth century. In the 1970s as cognitivism gained traction with educators, designers began to envision learning technology that employed artificial intelligence models that could adapt to individual learners. Computer-supported collaborative learning emerged as a strategy rich with research implications for the growing philosophies of constructivism and social cognitivism.

Though studies in collaborative learning and technology took place throughout the 1980s and 90s, the earliest public workshop directly addressing CSCL was "Joint Problem Solving and Microcomputers" which took place in San Diego in 1983. Six years later in 1989, the term "computer-supported collaborative learning" was used in a NATO-sponsored workshop in Maratea, Italy. A biannual CSCL conference series began in 1995. At the 2002 and 2003 CSCL conferences, the International Society of the Learning Sciences (ISLS) was established to run the CSCL and ICLS conference series and the International Journal of Computer-Supported Collaborative Learning (ijCSCL) and JLS journals.

The ijCSCL was established by the CSCL research community and ISLS. It began quarterly publication by Springer in 2006. It is peer reviewed and published both online and in print. Since 2009, it has been rated by ISI as being in the top 10% of educational research journals based on its impact factor.

The rapid development of social media technologies and the increasing need of individuals to understand and use those technologies has brought researchers from many disciplines to the field of CSCL. CSCL is used today in traditional and online schools and knowledge-building communities such as Wikipedia.

Theories

The field of CSCL draws heavily from a number of learning theories that emphasize that knowledge is the result of learners interacting with each other, sharing knowledge, and building knowledge as a group. Since the field focuses on collaborative activity and collaborative learning, it inherently takes much from constructivist and social cognitivist learning theories.

Precursor theories

The roots of collaborative epistemology as related to CSCL can be found in Vygotsky's social learning theory. Of particular importance to CSCL is the theory's notion of internalization, or the idea that knowledge is developed by one's interaction with one's surrounding culture and society. The second key element is what Vygotsky called the Zone of proximal development. This refers to a range of tasks that can be too difficult for a learner to master by themselves but is made possible with the assistance of a more skilled individual or teacher. These ideas feed into a notion central to CSCL: knowledge building is achieved through interaction with others.

Cooperative learning, though different in some ways from collaborative learning, also contributes to the success of teams in CSCL environments. The distinction can be stated as: cooperative learning focuses on the effects of group interaction on individual learning whereas collaborative learning is more concerned with the cognitive processes at the group unit of analysis such as shared meaning making and the joint problem space. The five elements for effective cooperative groups identified by the work of Johnson and Johnson are positive interdependence, individual accountability, promotive interaction, social skills, and group processing. Because of the inherent relationship between cooperation and collaboration, understanding what encourages successful cooperation is essential to CSCL research.

In the late 1980s and early 1990s, Marlene Scardamalia and Carl Bereiter wrote seminal articles leading to the development of key CSCL concepts: knowledge-building communities and knowledge-building discourse, intentional learning, and expert processes. Their work led to an early collaboration-enabling technology known as the Computer Supported Intentional Learning Environment (CSILE). Characteristically for CSCL, their theories were integrated with the design, deployment, and study of the CSCL technology. CSILE later became Knowledge Forum, which is the most widely used CSCL technology worldwide to date.

Other learning theories that provide a foundation for CSCL include distributed cognition, problem-based learning, group cognition, cognitive apprenticeship, and situated learning. Each of these learning theories focuses on the social aspect of learning and knowledge building, and recognizes that learning and knowledge building involve inter-personal activities including conversation, argument, and negotiation.

Collaboration theory and group cognition

Only in the last 15 to 20 years have researchers begun to explore the extent to which computer technology could enhance the collaborative learning process. While researchers, in general, have relied on learning theories developed without consideration of computer-support, some have suggested that the field needs to have a theory tailored and refined for the unique challenges that confront those trying to understand the complex interplay of technology and collaborative learning.

Collaboration theory, suggested as a system of analysis for CSCL by Gerry Stahl in 2002-2006, postulates that knowledge is constructed in social interactions such as discourse. The theory suggests that learning is not a matter of accepting fixed facts, but is the dynamic, on-going, and evolving result of complex interactions primarily taking place within communities of people. It also emphasizes that collaborative learning is a process of constructing meaning and that meaning creation most often takes place and can be observed at the group unit of analysis. The goal of collaboration theory is to develop an understanding of how meaning is collaboratively constructed, preserved, and re-learned through the media of language and artifacts in group interaction. There are four crucial themes in collaboration theory: collaborative knowledge building (which is seen as a more concrete term than "learning"); group and personal perspectives intertwining to create group understanding; mediation by artifacts (or the use of resources which learners can share or imprint meaning on); and interaction analysis using captured examples that can be analyzed as proof that the knowledge building occurred.

Collaboration theory proposes that technology in support of CSCL should provide new types of media that foster the building of collaborative knowing; facilitate the comparison of knowledge built by different types and sizes of groups; and help collaborative groups with the act of negotiating the knowledge they are building. Further, these technologies and designs should strive to remove the teacher as the bottleneck in the communication process to the facilitator of student collaboration. In other words, the teacher should not have to act as the conduit for communication between students or as the avenue by which information is dispensed, but should structure the problem-solving tasks. Finally, collaboration theory-influenced technologies will strive to increase the quantity and quality of learning moments via computer-simulated situations.

Stahl extended his proposals about collaboration theory during the next decade with his research on group cognition. In his book on "Group Cognition", he provided a number of case studies of prototypes of collaboration technology, as well as a sample in-depth interaction analysis and several essays on theoretical issues related to re-conceptualizing cognition at the small-group unit of analysis. He then launched the Virtual Math Teams project at the Math Forum, which conducted more than 10 years of studies of students exploring mathematical topics collaboratively online. "Studying VMT" documented many issues of design, analysis and theory related to this project. The VMT later focused on supporting dynamic geometry by integrating a multi-user version of GeoGebra. All aspects of this phase of the VMT project were described in "Translating Euclid." Then, "Constructing Dynamic Triangles Together" provided a detailed analysis of how a group of four girls learned about dynamic geometry by enacting a series of group practices during an eight-session longitudinal case study. Finally, "Theoretical Investigations: Philosophical Foundations of Group Cognition" collected important articles on the theory of collaborative learning from the CSCL journal and from Stahl's publications. The VMT project generated and analyzed data at the small-group unit of analysis, to substantiate and refine the theory of group cognition and to offer a model of design-based CSCL research.

Strategies

Currently, CSCL is used in instructional plans in classrooms both traditional and online from primary school to post-graduate institutions. Like any other instructional activity, it has its own prescribed practices and strategies which educators are encouraged to employ in order to use it effectively. Because its use is so widespread, there are innumerable scenarios in the use of CSCL, but there are several common strategies that provide a foundation for group cognition.

One of the most common approaches to CSCL is collaborative writing. Though the final product can be anything from a research paper, a Wikipedia entry, or a short story, the process of planning and writing together encourages students to express their ideas and develop a group understanding of the subject matter. Tools like blogs, interactive whiteboards, and custom spaces that combine free writing with communication tools can be used to share work, form ideas, and write synchronously.

Technology-mediated discourse refers to debates, discussions, and other social learning techniques involving the examination of a theme using technology. For example, wikis are a way to encourage discussion among learners, but other common tools include mind maps, survey systems, and simple message boards. Like collaborative writing, technology-mediated discourse allows participants that may be separated by time and distance to engage in conversations and build knowledge together.

Group exploration refers to the shared discovery of a place, activity, environment or topic among two or more people. Students do their exploring in an online environment, use technology to better understand a physical area, or reflect on their experiences together through the Internet. Virtual worlds like Second Life and Whyville as well as synchronous communication tools like Skype may be used for this kind of learning. Educators may use Orchestration Graphs to define activities and roles that students must adopt during learning, and analyzing afterwards the learning process.

Problem-based learning is a popular instructional activity that lends itself well to CSCL because of the social implications of problem solving. Complex problems call for rich group interplay that encourages collaboration and creates movement toward a clear goal.

Project-based learning is similar to problem-based learning in that it creates impetus to establish team roles and set goals. The need for collaboration is also essential for any project and encourages team members to build experience and knowledge together. Although there are many advantages to using software that has been specifically developed to support collaborative learning or project-based learning in a particular domain, any file sharing or communication tools can be used to facilitate CSCL in problem- or project-based environments.

When Web 2.0 applications (wikies, blogs, RSS feed, collaborative writing, video sharing, social networks, etc.) are used for computer-supported collaborative learning specific strategies should be used for their implementation, especially regarding (1) adoption by teachers and students; (2) usability and quality in use issues; (3) technology maintenance; (4) pedagogy and instructional design; (5) social interaction between students; (6) privacy issues; and (7) information/system security.

Teacher roles

Though the focus in CSCL is on individuals collaborating with their peers, teachers still have a vital role in facilitating learning. Most obviously, the instructor must introduce the CSCL activity in a thoughtful way that contributes to an overarching design plan for the course. The design should clearly define the learning outcomes and assessments for the activity. In order to assure that learners are aware of these objectives and that they are eventually met, proper administration of both resources and expectations is necessary to avoid learner overload. Once the activity has begun, the teacher is charged with kick-starting and monitoring discussion to facilitate learning. He or she must also be able to mitigate technical issues for the class. Lastly, the instructor must engage in assessment, in whatever form the design calls for, in order to ensure objectives have been met for all students.

Without the proper structure, any CSCL strategy can lose its effectiveness. It is the responsibility of the teacher to make students aware of what their goals are, how they should be interacting, potential technological concerns, and the time-frame for the exercise. This framework should enhance the experience for learners by supporting collaboration and creating opportunities for the construction of knowledge. Another important consideration of educators who implement online learning environments is affordance. Students who are already comfortable with online communication often choose to interact casually. Mediators should pay special attention to make students aware of their expectations for formality online. While students sometime have frames of reference for online communication, they often do not have all of the skills necessary to solve problems by themselves. Ideally, teachers provide what is called "scaffolding", a platform of knowledge that they can build on. A unique benefit of CSCL is that, given proper teacher facilitation, students can use technology to build learning foundations with their peers. This allows instructors to gauge the difficulty of the tasks presented and make informed decisions about the extent of the scaffolding needed.

Effects

According to Salomon (1995), the possibility of intellectual partnerships with both peers and advanced information technology has changed the criteria for what is counted to be the effects of technology. Instead of only concentrating on the amount and quality of learning outcomes, we need to distinguish between two kinds of effects: that is, "effects with a tool and/or collaborating peers, and effects of these." He used the term called "effects with" which is to describe the changes that take place while one is engaged in intellectual partnership with peers or with a computer tool. For example, the changed quality of problem solving in a team. And he means the word "effects of" more lasting changes that take place when computer-enhanced collaboration teaches students to ask more exact and explicit questions even when not using that system.

Applications

It has a number of implications for instructional designers, developers, and teachers.

  • First, it revealed what technological features or functions were particularly important and useful to students in the context of writing, and how a CSCL system could be adapted for use for different subject areas, which have specific implications for instructional designers or developers to consider when designing CSCL tools.
  • Second, this study also suggested the important role of a teacher in designing the scaffolds, scaffolding the collaborative learning process, and making CSCL a success. Third, it is important that a meaningful, real-world task is designed for CSCL in order to engage students in authentic learning activities of knowledge construction.
  • Third, cooperative work in the classroom, using as a tool based technology devices "one to one " where the teacher has a program of classroom management, allows not only the enhancement of teamwork where each member takes responsibilities involving the group, but also a personalized and individualized instruction, adapting to the rhythms of the students, and allowing to achieve the targets set in which has been proposed for them individualized Work Plan.

Criticism and concerns

Though CSCL holds promise for enhancing education, it is not without barriers or challenges to successful implementation. Obviously, students or participants need sufficient access to computer technology. Though access to computers has improved in the last 15 to 20 years, teacher attitudes about technology and sufficient access to Internet-connected computers continue to be barriers to more widespread usage of CSCL pedagogy.

Furthermore, instructors find that the time needed to monitor student discourse and review, comment on, and grade student products can be more demanding than what is necessary for traditional face-to-face classrooms. The teacher or professor also has an instructional decision to make regarding the complexity of the problem presented. To warrant collaborative work, the problem must be of sufficient complexity, otherwise teamwork is unnecessary. Also, there is risk in assuming that students instinctively know how to work collaboratively. Though the task may be collaborative by nature, students may still need training on how to work in a truly cooperative process.

Others have noted a concern with the concept of scripting as it pertains to CSCL. There is an issue with possibly over-scripting the CSCL experience and in so doing, creating "fake collaboration". Such over-scripted collaboration may fail to trigger the social, cognitive, and emotional mechanisms that are necessary to true collaborative learning.

There is also the concern that the mere availability of the technology tools can create problems. Instructors may be tempted to apply technology to a learning activity that can very adequately be handled without the intervention or support of computers. In the process of students and teachers learning how to use the "user-friendly" technology, they never get to the act of collaboration. As a result, computers become an obstacle to collaboration rather than a supporter of it.

For second language acquisition

History

The advent of computer-supported collaborative learning (CSCL) as an instructional strategy for second language acquisition can be traced back to the 1990s. During that time, the internet was growing rapidly, which was one of the key factors that facilitated the process. At the time, the first wikis (such as WikiWikiWeb) were still undergoing early development, but the use of other tools such as electronic discussion groups allowed for equal participation amongst peers, particularly benefiting those who would normally not participate otherwise during face-to-face interactions.

During the establishment of wikis in the 2000s, global research began to emerge regarding their effectiveness in promoting second language acquisition. Some of this research focused on more specific areas such as systemic-functional linguistics, humanistic education, experiental learning, and psycholinguistics. For example, in 2009 Yu-Ching Chen performed a study to determine the overall effectiveness of wikis in an English as a second language class in Taiwan. Another example is a 2009 study by Greg Kessler in which pre-service, non-native English speaker teachers in a Mexican university were given the task to collaborate on a wiki, which served as the final product for one of their courses. In this study, emphasis was placed on the level of grammatical accuracy achieved by the students throughout the course of the task.

Due to the continual development of technology, other educational tools aside from wikis are being implemented and studied to determine their potential in scaffolding second language acquisition. According to Mark Warschauer (2010), among these are blogs, automated writing evaluation systems, and open-source netbooks. Ex situ of the classroom, the development of other recent online tools such as Livemocha (2007) have facilitated language acquisition via member-to-member interactions, demonstrating firsthand the impact the advancement of technology has made towards meeting the varying needs of language learners.

Effectiveness and perception

Studies in the field of computer-assisted language learning (CALL) have shown that computers provide material and valuable feedback for language learners and that computers can be a positive tool for both individual and collaborative language learning. CALL programs offer the potential for interactions between the language learners and the computer. Additionally, students' autonomous language learning and self-assessment can be made widely available through the web. In CSCL, the computer is not only seen as a potential language tutor by providing assessment for students' responses, but also as a tool to give language learners the opportunity to learn from the computer and also via collaboration with other language learners. Juan focuses on new models and systems that perform efficient evaluation of student activity in online-based education. Their findings indicate that CSCL environments organized by teachers are useful for students to develop their language skills. Additionally, CSCL increases students' confidence and encourages them to maintain active learning, reducing the passive reliance on teachers' feedback. Using CSCL as a tool in the second language learning classroom has also shown to reduce learner anxiety.

Various case studies and projects had been conducted in order to measure the effectiveness and perception of CSCL in a language learning classroom. After a collaborative internet-based project, language learners indicated that their confidence in using the language had increased and that they felt more motivated to learn and use the target language. After analyzing student questionnaires, discussion board entries, final project reports, and student journals, Dooly suggests that during computer supported collaborative language learning, students have an increased awareness of different aspects of the target language and pay increased attention to their own language learning process. Since the participants of her project were language teacher trainees, she adds that they felt prepared and willing to incorporate online interaction in their own teaching in the future.

Cultural considerations

Culture may be thought of as composed of "beliefs, norms, assumptions, knowledge, values, or sets of practice that are shared and form a system". Learning communities focused in whole or part on second language acquisition may often be distinctly multicultural in composition, and as the cultural background of individual learners affects their collaborative norms and practices, this can significantly impact their ability to learn in a CSCL environment.

CSCL environments are generally valued for the potential to promote collaboration in cross-cultural learning communities. Based on social constructivist views of learning, many CSCL environments fundamentally emphasize learning as the co-construction of knowledge through the computer-mediated interaction of multivoiced community members. Computer-mediation of the learning process has been found to afford consideration of alternative viewpoints in multicultural/multilingual learning communities. When compared to traditional face-to-face environments, computer-mediated learning environments have been shown to result in more equal levels of participation for ESL students in courses with native English speakers. Language barriers for non-native speakers tend to detract from equal participation in general, and this can be alleviated to some extent through the use of technologies which support asynchronous modes of written communication.

Online learning environments however tend to reflect the cultural, epistemological, and pedagogical goals and assumptions of their designers. In computer-supported collaborative learning environments, there is evidence that cultural background may impact learner motivation, attitude towards learning and e-learning, learning preference (style), computer usage, learning behavior and strategies, academic achievement, communication, participation, knowledge transfer, sharing and collaborative learning. Studies variously comparing Asian, American and Danish and Finnish learners have suggested that learners from different cultures exhibit different interaction patterns with their peers and teachers in online. A number of studies have shown that difference in Eastern and Western educational cultures, for instance, which are found in traditional environments are also present in online environments. Zhang has described Eastern education as more group-based, teacher-dominated, centrally organized, and examination-oriented than Western approaches. Students who have learned to learn in an Eastern context emphasizing teacher authority and standardized examinations may perform differently in a CSCL environment characterized by peer critique and co-construction of educational artifacts as the primary mode of assessment.

Design implications

A "multiple cultural model" of instructional design emphasizes variability and flexibility in the process of designing for multicultural inclusiveness, focusing on the development of learning environments reflecting the multicultural realities of society, include multiple ways of teaching and learning, and promote equity of outcomes. McLoughlin, C. & Oliver propose a social, constructivist approach to the design of culturally-sensitive CSCL environments which emphasizes flexibility with regard to specific learning tasks, tools, roles, responsibilities, communication strategies, social interactions, learning goals and modes of assessment [B5]. Constructivist instructional design approaches such as R2D2 which emphasize reflexive, recursive, participatory design of learning experiences may be employed in developing CSCL which authentically engages learners from diverse linguistic and cultural backgrounds.

Dyslexia in Computer-Supported Collaborative Learning

History

Dyslexia primarily involves difficulties with reading, spelling and sentence structure, transposition, memory, organization and time management, and lack of confidence. Dyslexia has in the past two decades become increasingly present in research and legislation. The United Kingdom passed the Disability Discrimination Act 1995 in which institutions were required to "reasonably adjust" instruction for students with disabilities, particularly physical and sensory disabilities; in 2002, the Special Education Needs and Disabilities Act adjusted the legislation to include learning disabilities.

The Americans with Disabilities Act of 1990 (ADA) established that all students with disabilities must be included in all state and districtwide assessments of student progress. The ADA also guarantees equal accommodation for the disabled in, "employment, public accommodations, state and local government services, transportation, and telecommunications."

In recent years, tools such as WebHelpDyslexia and other capabilities of web applications have increased the availability of tools to provide coping skills for students with dyslexia.

Research on Dyslexia in E-Learning Environments

In 2006, Woodfine argued that dyslexia can impact the ability of a student to participate in synchronous e-learning environments, especially if activities being completed are text-based. During experimental qualitative research, Woodfine found that data suggested "learners with dyslexia might suffer from embarrassment, shame and even guilt about their ability to interact with other learners when in a synchronous environment."

In a study by Fichten et al., it was found that assistive technology can be beneficial in aiding students with the progression of their reading and writing skills. Tools such as spell check or text-to-speech can be helpful to learners with dyslexia by allowing them to focus more on self-expression and less on errors.

Design implications

Alsobhi, et al., examined assistive technologies for dyslexic students and concluded that the most fundamental considerations to be had when serving students of this population are: "the learning styles that people with dyslexia exhibit, and how assistive technology can be adapted to align with these learning behaviors."

The Dyslexia Adaptive E-Learning (DAEL) is a suggested a framework that proposes four dimensions that cover 26 attributes. The proposed framework asks educators to make decisions based on perceived ease of use, perceived usefulness, and system adaptability:

  • perceived ease of use: This refers to the degree to which a student believes that using the technology is free of effort. One technique to increase the perceived ease of use includes utilizing technology in which self-descriptiveness is present. This, coupled with clarity and logical flow of functions, makes the learning process easier and the interaction between the user and machine more convenient.
  • perceived usefulness: Defined as how a student's performance, or learning performance, can be enhanced by a system. Studies show the impact of perceived ease of use and perceived usefulness and their role in a users' decision on whether to use a system again. Scaffolding as well as accommodations to the student's learning style will help overcome limitations of system operations, as will feedback geared toward system improvements.
  • system adaptability: Refers to the user experiences and the way in which students are given control over a system to increase confidence and comfort in their learning. In addition to implications for the system, the flow of content shouldb be logical and the tone (attitude) of content should be encouraging.

508 Compliance & the implications for Educators

Educators that choose to use the CSCL environment must be aware of 508 compliance and its legal implications. "In the U.S., the criteria for designing Web pages accessibly are provided by two major sets: the W3C's Web Accessibility Guidelines (WCAG) and the design standards issued under U.S. federal law, Section 508 of the Rehabilitation Act, as amended in 1998.1 Features of accessible design include, among others, the provision of ALT tags for nontextual elements, such as images, animations and image map hot spots; meaningful link text; logical and persistent page organization, and the inclusion of skip navigation links."

Unfortunately, not all educators are exposed to these guidelines, especially if their collegiate programs do not provide exposure to the use of computers, aspects of web design or technology in education. In some cases, it may be advantageous for the educator to collaborate with an instructional technologist or web designer to ensure 508 guidelines are addressed in the desired learning environment for the CSCL.

Web 3.0 and Computer-Supported Collaborative Learning (CSCL)

The World Wide Web began as information sharing on static webpages accessible on a computer through the use of a web browser. As more interactive capabilities were added, it evolved into Web 2.0, which allowed for user-generated content and participation (e.g. social networking). This opened up many new possibilities for computer-supported collaborative learning (CSCL) using the Internet. The internet is now entering a new phase, Web 3.0 or the Semantic Web, which is characterized by the greater interconnectivity of machine-readable data from many different sources. New intelligent technology applications will be able to manage, organize and create meaning from this data, which will have a significant impact on CSCL.

The interconnectivity of machine-readable data with semantic tags means that searches will be greatly enhanced. Search results will be more relevant, recommendations of resources will be made based on search terms and results will include multimedia content.

New Web 3.0 capabilities for learners include enhanced tools for managing learning, allowing them to self-regulate and co-regulate learning without the assistance of an instructor. Through the use of Web 3.0, groups and communities can be formed according to specific criteria without human input. These communities and groups can provide support to new learners and give experts an opportunity to share their knowledge.

Teachers can benefit from these same capabilities to manage their teaching. In addition, the software for Web 3.0 collaboration will include using data from group communications, which then generates how much each individual has collaborated based on how often they communicate and how long their messages are.

Examples of new Web 3.0 tools to enhance CSCL

Virtual Assistants and Intelligent Agents

Making data machine-readable is leading to the development of virtual assistants and intelligent agents. These are tools which can access data on a user's behalf and will be able to assist learners and collaborators in several ways. They can provide personalized and customized search results by accessing data on a variety of platforms, recommend resources based on user information and preferences, manage administrative tasks, communicate with other agents and databases, and help organize information and interactions with collaborators.

Virtual Learning Communities

Virtual learning communities are cyberspaces that allow for individual and collaborative learning to take place. While they exist today, with Web 3.0 they will gain enhanced features enabling more collaborative learning to take place. Some describe them as evolving out of existing learning management systems (LMSs), adding intelligent agents and virtual assistants that can enhance content searches and deal with administrative and communication tasks, or enabling different LMSs around the world to communicate with each other, creating an even larger community to share resources and locate potential collaborators. Virtual learning communities will also enable different types of peer-to-peer interaction and resource sharing to support co-construction of knowledge. These communities may also include some aspects of 3D gaming and VR.

Non-immersive and Immersive 3D Virtual Environments

Through the use of 3D gaming, users can simulate lives of others while providing their knowledge throughout the 3D environment as an avatar. These 3D environments also foster simulation and scenario building for places where users would otherwise not have access. The 3D environments facilitate online knowledge building communities. Non-immersive environments are environments in which not all five senses are used but still allows users to interact in virtual worlds. Virtual Reality (VR) headsets are sometimes used to give users a full immersion experience, into these 3D virtual worlds. This allows users to interact with each other in real time and simulate different learning situations with other users. These learning experiences and environments vary between fields and learning goals. Certain virtual reality headsets allow users to communicate with each other while being in different physical locations.

Multimodal literacy development in CSCL

The concept of Multimodal literacy

Multimodal literacy is the way processes of literacy - reading, writing, talking, listening and viewing - are occurring within and around new communication media. (Kress & Jewitt, 2003; Pahl & Rowsell, 2005; Walsh, 2008) It refers to meaning-making that occurs through the reading, viewing, understanding, responding to and producing and interacting with multimedia and digital texts. (Walsh, 2010)

Literature review on multi-modal literacy in CSCL

* Online forum

Online forums offer numerous advantages for both teacher and students for collaborative learning online. Discussion forums provide a wider platform to exchange information and ideas, to develop writing and reading skills, critical thinking skills. (Jill Margerison, 2013) A collaborative online forum can also help students learn about the unique challenges of online communication, especially the need for clarity and the dangers of sarcasm. (Susan Martens-Baker, 2009) For the teacher, they offer a flexible platform from which to educate in a participatory culture, where teachers and students can interact with each other and create new knowledge. (Jill Margerison, 2013)

* Video games

Video games were designed as a learning tool engaged learners who advance through experimentation, critical thinking and practice in the virtual world. (Abrams, 2009) Video games in CSCL can promote positive interdependence, individual accountability, face-to-face promotive interaction, social skills, and group processing abilities in the ELA classroom. Through interactions in the virtual world, learners have the opportunities to establish their presence, identity and create meanings for their lives.

* Multimodal composition in digital storytelling: podcast, video/ audio crafts

Digital storytelling refers to integrating a variety of means, such as images, audio, video, graphics and diagram to personal narratives and crafts. Four skill competencies: reading, writing, speaking, and listening would be enhanced by producing digital products. (Brenner, 2014) Students have a greater sense of autonomy, agency through the digital storytelling in CSCL.

The implication for classroom teaching

* Online-forum

Online forums provide opportunities for young people to engage in the self-exposition as they practice digital literacies and hone the skill of movement across multiple literacies, languages and subject positions. Meanwhile, identity is a constellation of the multiple communities. It is also important to emphasize the potentially harmful cultural discourses that occur within young people's consumption. (Kim, 2015)

* Videogame

Through capitalizing on students' gaming experiences by recognizing how they apply to the subject at hand, teachers can highlight the benefits of virtual learning environments and draw upon students' gaming experiences to understand their application of virtual learning across curricula. Educators need to choose the appropriate game for the particular subject to endorse their instruction and promote collaboration among students.

Multimodal composition: podcast, audio, video crafts in digital storytelling

Students who engage in collaborative learning for creating digital production show the characteristics of leadership. Moreover, students would gain the experience of collaboration and expand their skill of the multimodal literacy. In addition, digital composition provides a meaningful tool for teachers to assess. (Brenner, 2014)

Applications for ELLs

Multimodal literacy can facilitate English learners' literacy learning. It has provided opportunities for English learners to expand the interpretation of texts. (Ajayi, 2009) Specifically, English language learners can increase their language ability through computer-collaborative learning. The multimodality platforms provide students, especially ELLs with an anxiety-free zone to collaborate with their peers in a virtual world in order to make meanings together. Technology self-efficacy increases ELLs' level of independence and reduces their level of anxiety. (Mellati, Zangoei & Khademi, 2015) ELLs will have more motivation and self-confident while participating in online group projects to make contributions and share knowledge with their peers. As a result of collaborative learning, ELLs would expand their vocabulary, gain advanced and more academic grammars.

CSCL in Post-Secondary Education

Overview of CSCL in Post-Secondary Education

Research on CSCL in post-secondary education settings

The applications of CSCL in post-secondary education demonstrate positive impacts on students' learning such as promoting learner interaction, motivation and understanding. As collaborative learning is grounded in social constructivism, the interaction and collaboration during learning is valued.

Developing Professional Skills

There's research findings that shows online students had higher scores than face-to-face students in professional competence acquisition test, showing the effectiveness of CSCL in promoting the development of professional skills

Knowledge Building

Knowledge co-construction among geographically dispersed students in an online postgraduate program was explained in a study as students relied heavily on each other for their on-going participation in the online discussions and joint refinement of ideas introduced.

Design Principles & Instructional Strategies for CSCL in Post-Secondary Education

The design principles for using CSCL can be considered from different perspectives. For technical use, instructors need to provide tutorials and online training modules to students. For collaboration, students need time to plan and coordinate group work as well as instructors' support and guidance on the discussions. Also, group size and composition should be taken into consideration for better quality of interaction. More instructional strategies are presented below.

Project-Based Settings Using Wikis

Wikis is a tool for learners to co-construct knowledge online with the access to create and edit contents. There are three phases of using wikis for collaborative writing:

Phase 1. Crisis of Authority

Users experience challenges due to unfamiliarity with the use of wiki and the unknown of other teammates' boundaries of being commented or revised on their writings.

Phase 2. Crisis of Relationship

Collaborative learning emerges and group communication is improved.

Phase 3. Resolution of Crisis

More frequent communication occurs and increased co-writing among team members.

To better design wiki-based project, the design principles design include:

1. Provide learners with a practice article to edit at the beginning of a course for getting familiar with using wikis

2. Informs learners of different communication tools to work collaboratively.

3. Engage learners with repeated wiki article assignments.

4. Provide timely feedback on students' discussion, participation and interaction.

Online Learning Management Systems

The characteristic of social interaction in CSCL can be demonstrated on the online learning community where learners can communicate with each other. One of the medium facilitating the online community to work is online learning management system that provides all people including learners, professors, and administrative staff to communicate.

When using an online learning management system for collaborative learning, the instructor should provide technical training by presenting video tutorials, online training modules or online workshops.

Mobile Computer Supported Collaborative Learning

Mobile CSCL (mCSCL) is beneficial to students' learning achievements, attitude and interactions. The suggested design principles from CSCL include:

1. An idea group size is around 3 to 4 people.

2. A duration between 1 and 4 weeks demonstrate better effects. The criticisms version indicate in the case of short term course the interactions networks not consolidate.

Professional Teaching Community

Professional teacher communities are positively related to student learning, teacher learning, teacher practice and school culture. Teacher collaboration is a significant element of these communities. Reflection‐oriented tasks (such as reflection on teaching performance in individual writing, peer feedback, and collective writing) stimulated participation, and in combination with task structure also interaction in these communities. Furthermore, structured tasks(such as crossword puzzles, the path to come to a solution is unambiguous and answers can be immediately checked) which required critical reflection on personal experiences and perspectives triggered task‐related communication and a deep level of information exchange.

Distance Learning

The European Union Comenius fund sponsored FISTE project which is concerned with the educational use of information and communication technologies (ICTs), specifically with the development and dissemination of a new pedagogical strategy for distance learning through in-service teacher education in schools across Europe. This project uses the online Virtual Learning Environment platform BSCW as a Computer Supportive Communication Learning tool to facilitate the way the participants work together. This work has involved schools and teacher training providers, building culturally different work in in-service teacher education in the participating countries. The value of using CSCL supported technology for in-service teacher education in Europe lies in the concept of hinterland. Cross-national courses like the FISTE would be difficult to run without this technological approach.

Forest gardening

From Wikipedia, the free encyclopedia
 
Robert Hart's forest garden in Shropshire

Forest gardening is a low-maintenance, sustainable, plant-based food production and agroforestry system based on woodland ecosystems, incorporating fruit and nut trees, shrubs, herbs, vines and perennial vegetables which have yields directly useful to humans. Making use of companion planting, these can be intermixed to grow in a succession of layers to build a woodland habitat. Forest gardening is a prehistoric method of securing food in tropical areas. In the 1980s, Robert Hart coined the term "forest gardening" after adapting the principles and applying them to temperate climates.

History

Since prehistoric times hunter-gatherers might have influenced forests, for instance in Europe by Mesolithic people bringing favored plants like hazel with them. Forest gardens are probably the world's oldest form of land use and most resilient agroecosystem. They originated in prehistoric times along jungle-clad river banks and in the wet foothills of monsoon regions. In the gradual process of families improving their immediate environment, useful tree and vine species were identified, protected and improved whilst undesirable species were eliminated. Eventually superior foreign species were selected and incorporated into the gardens. First Nation villages in Alaska with forest gardens, that were filled with nuts, stone fruit, berries, and herbs, were noted by an archeologist from the Smithsonian in the 1930s.

Forest gardens are still common in the tropics and known by various names such as: home gardens in Kerala in South India, Nepal, Zambia, Zimbabwe and Tanzania; Kandyan forest gardens in Sri Lanka; huertos familiares, the "family orchards" of Mexico. These are also called agroforests and, where the wood components are short-statured, the term shrub garden is employed. Forest gardens have been shown to be a significant source of income and food security for local populations.

Robert Hart adapted forest gardening for the United Kingdom's temperate climate during the 1980s. His theories were later developed by Martin Crawford from the Agroforestry Research Trust and various permaculturalists such as Graham Bell, Patrick Whitefield, Dave Jacke and Geoff Lawton.

In temperate climates

Robert Hart, forest gardening pioneer

Hart began farming at Wenlock Edge in Shropshire with the intention of providing a healthy and therapeutic environment for himself and his brother Lacon. Starting as relatively conventional smallholders, Hart soon discovered that maintaining large annual vegetable beds, rearing livestock and taking care of an orchard were tasks beyond their strength. However, a small bed of perennial vegetables and herbs he planted was looking after itself with little intervention.

Following Hart's adoption of a raw vegan diet for health and personal reasons, he replaced his farm animals with plants. The three main products from a forest garden are fruit, nuts and green leafy vegetables. He created a model forest garden from a 0.12 acre (500 m2) orchard on his farm and intended naming his gardening method ecological horticulture or ecocultivation. Hart later dropped these terms once he became aware that agroforestry and forest gardens were already being used to describe similar systems in other parts of the world. He was inspired by the forest farming methods of Toyohiko Kagawa and James Sholto Douglas, and the productivity of the Keralan home gardens as Hart explains: "From the agroforestry point of view, perhaps the world's most advanced country is the Indian state of Kerala, which boasts no fewer than three and a half million forest gardens ... As an example of the extraordinary intensity of cultivation of some forest gardens, one plot of only 0.12 hectares (0.30 acres) was found by a study group to have twenty-three young coconut palms, twelve cloves, fifty-six bananas, and forty-nine pineapples, with thirty pepper vines trained up its trees. In addition, the smallholder grew fodder for his house-cow."

Seven-layer system

The seven layers of the forest garden

Robert Hart pioneered a system based on the observation that the natural forest can be divided into distinct levels.

He used intercropping to develop an existing small orchard of apples and pears into an edible polyculture landscape consisting of the following layers:

  1. Canopy layer consisting of the original mature fruit trees.
  2. Low-tree layer of smaller nut and fruit trees on dwarfing rootstocks.
  3. Shrub layer of fruit bushes such as currants and berries.
  4. Herbaceous layer of perennial vegetables and herbs.
  5. Rhizosphere or ‘underground’ dimension of plants grown for their roots and tubers.
  6. Ground cover layer of edible plants that spread horizontally.
  7. ‘Vertical layer’ of vines and climbers.

A key component of the seven-layer system was the plants he selected. Most of the traditional vegetable crops grown today, such as carrots, are sun-loving plants not well selected for the more shady forest garden system. Hart favored shade-tolerant perennial vegetables.

Further development

The Agroforestry Research Trust, managed by Martin Crawford, runs experimental forest gardening projects on a number of plots in Devon, United Kingdom. Crawford describes a forest garden as a low-maintenance way of sustainably producing food and other household products.

Ken Fern had the idea that for a successful temperate forest garden a wider range of edible shade tolerant plants would need to be used. To this end, Fern created the organisation Plants for a Future which compiled a plant database suitable for such a system. Fern used the term woodland gardening, rather than forest gardening, in his book Plants for a Future.

Kathleen Jannaway, the cofounder of Movement for Compassionate Living (MCL) with her husband Jack, wrote a book outlining a sustainable vegan future called Abundant Living in the Coming Age of the Tree in 1991. The MCL promotes forest gardening and other types of vegan organic gardening. In 2009 it provided a grant of £1,000 to the Bangor Forest Garden project in Gwynedd, North West Wales.

Kevin Bradley in the US called his property and nursery "Edible Forest" in 1985, which combined trees and field crops. Today, his business and the 2005 book Edible Forest Gardens have spawned little "edible forests" all over the world.

Permaculture

Bill Mollison, who coined the term permaculture, visited Robert Hart at his forest garden in Wenlock Edge in October 1990. Hart's seven-layer system has since been adopted as a common permaculture design element.

Numerous permaculturalists are proponents of forest gardens, or food forests, such as Graham Bell, Patrick Whitefield, Dave Jacke, Eric Toensmeier and Geoff Lawton. Bell started building his forest garden in 1991 and wrote the book The Permaculture Garden in 1995, Whitefield wrote the book How to Make a Forest Garden in 2002, Jacke and Toensmeier co-authored the two volume book set Edible Forest Gardens in 2005, and Lawton presented the film Establishing a Food Forest in 2008.

In tropical climates

Forest gardens, or home gardens, are common in the tropics, using intercropping to cultivate trees, crops, and livestock on the same land. In Kerala in south India as well as in northeastern India, the home garden is the most common form of land use and is also found in Indonesia. One example combines coconut, black pepper, cocoa and pineapple. These gardens exemplify polyculture, and conserve much crop genetic diversity and heirloom plants that are not found in monocultures. Forest gardens have been loosely compared to the religious concept of the Garden of Eden.

Americas

The BBC's Unnatural Histories claimed that the Amazon rainforest, rather than being a pristine wilderness, has been shaped by humans for at least 11,000 years through practices such as forest gardening and terra preta. Since the 1970s, numerous geoglyphs have been discovered on deforested land in the Amazon rainforest, furthering the evidence of Pre-Columbian civilizations.

On the Yucatán Peninsula, much of the Maya food supply was grown in "orchard gardens", known as pet kot. The system takes its name from the low wall of stones (pet meaning 'circular' and kot, 'wall of loose stones') that characteristically surrounds the gardens.

Africa

In many African countries, for example Zambia, Zimbabwe, Ethiopia and Tanzania, gardens are widespread in rural, periurban, and urban areas and they play an essential role in establishing food security. Most well known are the Chaga or Chagga gardens on the slopes of Mount Kilimanjaro in Tanzania. These are an example of an agroforestry system. In many countries, women are the main actors in home gardening and food is mainly produced for subsistence. In North Africa, oasis-layered gardening with palm trees, fruit trees, and vegetables is a traditional type of forest garden.

Plants

Some plants, such as wild yam, work as both a root plant and a vine. Ground covers: Low-growing edible 'forest garden plants help keep weeds in control and provide a great way to utilize areas that would otherwise be unused.

Plants

  • Cardamom
  • Ginger
  • Chervil
  • Bergamot
  • Sweet woodruff
  • Sweet cicely

Project

El Pilar on the BelizeGuatemala border features a forest garden to demonstrate traditional Maya agricultural practices. A further one acre model forest garden, called Känan K’aax (meaning 'well-tended garden' in Mayan), is funded by the National Geographic Society and developed at Santa Familia Primary School in Cayo.

In the United States, the largest known food forest on public land is believed to be the seven acre Beacon Food Forest in Seattle, Washington. Other forest garden projects include those at the central Rocky Mountain Permaculture Institute in Basalt, Colorado and Montview Neighborhood farm in Northampton, Massachusetts. The Boston Food Forest Coalition promotes local forest gardens.

In Canada Richard Walker has been developing and maintaining food forests in British Columbia for over 30 years. He developed a three acre food forest that at maturity provided raw materials for a plant nursery and herbal business as well as food for his family. The Living Centre has developed various forest garden projects in Ontario.

In the United Kingdom, other than those run by the Agroforestry Research Trust (ART), there are numerous forest garden projects such as the Bangor Forest Garden in Gwynedd, northwest Wales. Martin Crawford from ART administers the Forest Garden Network, an informal network of people and organisations who are cultivating forest gardens.

Since 2014, Gisela Mir and Mark Biffen have been developing a small-scale Edible Forest Garden ("Verger" in Catalan) in Cardedeu, a village near Barcelona, Catalunya. During their previous years of Permaculture training they were introduced to various Edible Forest Garden projects in Wales and other parts of the UK. It is intended as a space for experimentation and demonstration: "...we want to learn and test what it means to have an orchard in an area with a Mediterranean climate: which species grow well here; how to manage limiting aspects, such as water; and, above all, what design implications there are due to the characteristics of our climate and our latitude."  In April 2021, they published in Spanish the book "Food forests and edible gardens" (Bosques y jardines de alimentos) where they draw on their first experimental progresses and experiences, delving into the particularities of the Mediterranean climate through a book adapted to that climate and to those species. It is one of the first works on this subject not written in English.

Forest gardening in popular culture

A forest garden plays a significant role in the Video Read-Opera "Marisette's Voice," where it is the object of political machinations between two candidates for city council in the fictional city of Augusta, CY. It is also used as a metaphor for one type of society.

Water conservation

From Wikipedia, the free encyclopedia
 
United States 1960 postal stamp advocating water conservation

Water conservation includes all the policies, strategies and activities to sustainably manage the natural resource of fresh water, to protect the hydrosphere, and to meet the current and future human demand (thus avoiding water scarcity). Population, household size and growth and affluence all affect how much water is used. Factors such as climate change have increased pressures on natural water resources especially in manufacturing and agricultural irrigation. Many countries have already implemented policies aimed at water conservation, with much success. The key activities to conserve water are as follows: any beneficial reduction in water loss, use and waste of resources, avoiding any damage to water quality; and improving water management practices that reduce the use or enhance the beneficial use of water. Technology solutions exist for households, commercial and agricultural applications. Water conservation programs involved in social solutions are typically initiated at the local level, by either municipal water utilities or regional governments. Common strategies include public outreach campaigns, tiered water rates (charging progressively higher prices as water use increases), or restrictions on outdoor water use such as lawn watering and car washing.

Goals

The goals of water conservation efforts include:

Strategies

The key activities to conserve water are as follows:

  • Any beneficial reduction in water loss, use and waste of resources.
  • Avoiding any damage to water quality.
  • Improving water management practices that reduce the use or enhance the beneficial use of water.

One of the strategies in water conservation is rain water harvesting. Digging ponds, lakes, canals, expanding the water reservoir, and installing rain water catching ducts and filtration systems on homes are different methods of harvesting rain water. Many people in many countries keep clean containers so they can boil it and drink it, which is useful to supply water to the needy. Harvested and filtered rain water can be used for toilets, home gardening, lawn irrigation, and small scale agriculture.

Another strategy in water conservation is protecting groundwater resources. When precipitation occurs, some infiltrates the soil and goes underground. Water in this saturation zone is called groundwater. Contamination of groundwater causes the groundwater water supply to not be able to be used as a resource of fresh drinking water and the natural regeneration of contaminated groundwater can take years to replenish. Some examples of potential sources of groundwater contamination include storage tanks, septic systems, uncontrolled hazardous waste, landfills, atmospheric contaminants, chemicals, and road salts. Contamination of groundwater decreases the replenishment of available freshwater so taking preventative measures by protecting groundwater resources from contamination is an important aspect of water conservation.

An additional strategy to water conservation is practicing sustainable methods of utilizing groundwater resources. Groundwater flows due to gravity and eventually discharges into streams. Excess pumping of groundwater leads to a decrease in groundwater levels and if continued it can exhaust the resource. Ground and surface waters are connected and overuse of groundwater can reduce and, in extreme examples, diminish the water supply of lakes, rivers, and streams. In coastal regions, over pumping groundwater can increase saltwater intrusion which results in the contamination of groundwater water supply. Sustainable use of groundwater is essential in water conservation.

A fundamental component to water conservation strategy is communication and education outreach of different water programs. Developing communication that educates science to land managers, policy makers, farmers, and the general public is another important strategy utilized in water conservation. Communication of the science of how water systems work is an important aspect when creating a management plan to conserve that system and is often used for ensuring the right management plan to be put into action.

"Water Conservation Day" is celebrated on 22 March.

Social solutions

Water conservation programs involved in social solutions are typically initiated at the local level, by either municipal water utilities or regional governments. Common strategies include public outreach campaigns, tiered water rates (charging progressively higher prices as water use increases), or restrictions on outdoor water use such as lawn watering and car washing. Cities in dry climates often require or encourage the installation of xeriscaping or natural landscaping in new homes to reduce outdoor water usage. Most urban outdoor water use in California is residential, illustrating a reason for outreach to households as well as businesses.

One fundamental conservation goal is universal water metering. The prevalence of residential water metering varies significantly worldwide. Recent studies have estimated that water supplies are metered in less than 30% of UK households. Although individual water meters have often been considered impractical in homes with private wells or in multifamily buildings, the US Environmental Protection Agency estimates that metering alone can reduce consumption by 20 to 40 percent. In addition to raising consumer awareness of their water use, metering is also an important way to identify and localize water leakage. Water metering would benefit society, in the long run, it is proven that water metering increases the efficiency of the entire water system, as well as help unnecessary expenses for individuals for years to come. One would be unable to waste water unless they are willing to pay the extra charges, this way the water department would be able to monitor water usage by the public, domestic and manufacturing services.

Some researchers have suggested that water conservation efforts should be primarily directed at farmers, in light of the fact that crop irrigation accounts for 70% of the world's fresh water use. The agricultural sector of most countries is important both economically and politically, and water subsidies are common. Conservation advocates have urged removal of all subsidies to force farmers to grow more water-efficient crops and adopt less wasteful irrigation techniques.

New technology poses a few new options for consumers, features such as full flush and half flush when using a toilet are trying to make a difference in water consumption and waste. It is also possible to use/"pollute" the water in stages (keeping use in flush toilets for last), hereby allowing more use of the water for various tasks within a same cycle (before it needs to be purified again, which can also be done in-situ). Earthships often use such a setup.

Also available are modern shower heads that help reduce wasting water: Old shower heads are said to use 5-10 gallons per minute, while new fixtures available use 2.5 gallons per minute and offer equal water coverage. Another method is to recycle the water of the shower directly, by means a semi-closed system which features a pump and filter. Such a setup (called a "water recycling shower") has also been employed at the VIRTUe LINQ house. Besides recycling water, it also reuses the heat of the water (which would otherwise be lost).

Contrary to the popular view that the most effective way to save water is to curtail water-using behavior (e.g., by taking shorter showers), experts suggest the most efficient way is replacing toilets and retrofitting washers; as demonstrated by two household end use logging studies in the US.

Water-saving technology for the home includes:

  • Low-flow shower heads sometimes called energy-efficient shower heads as they also use less energy
  • Low-flush toilets, composting toilets and incinerating toilets. Composting toilets have a dramatic impact in the developed world, as conventional Western flush toilets use large volumes of water
  • Dual flush toilets include two buttons or handles to flush different levels of water. Dual flush toilets use up to 67% less water than conventional toilets
  • Faucet aerators, which break water flow into fine droplets to maintain "wetting effectiveness" while using less water. An additional benefit is that they reduce splashing while washing hands and dishes
  • Raw water flushing where toilets use sea water or non-purified water (i.e. greywater)
  • Wastewater reuse or recycling systems, allowing:
  • Rainwater harvesting
  • High-efficiency clothes washers
  • Weather-based irrigation controllers
  • Garden hose nozzles that shut off the water when it is not being used, instead of letting a hose run.
  • Low flow taps in wash basins
  • Swimming pool covers that reduce evaporation and can warm pool water to reduce water, energy and chemical costs.
  • Automatic faucet is a water conservation faucet that eliminates water waste at the faucet. It automates the use of faucets without the use of hands.

Smart water meters are also a promising technology for reducing household water usage. A study conducted in Valencia, Spain shows the potential that smart meter-based water consumption feedback has for conserving water in households. The findings showed that households that were equipped with smart water meters increased their water savings. This technology works to show people how much water they were using in their household, suggest ways they can reduce water usage, and incentivize water savings with physical rewards.

Commercial applications

Many water-saving devices (such as low-flush toilets) that are useful in homes can also be useful for business water saving. Other water-saving technology for businesses includes:

Agricultural applications

Overhead irrigation, center pivot design

Water is a very important part in irrigation. Plants always take a lot of ground water thus ground water should be replenished. For crop irrigation, optimal water efficiency means minimizing losses due to evaporation, runoff or subsurface drainage while maximizing production. An evaporation pan in combination with specific crop correction factors can be used to determine how much water is needed to satisfy plant requirements. Flood irrigation, the oldest and most common type, is often very uneven in distribution, as parts of a field may receive excess water in order to deliver sufficient quantities to other parts. Overhead irrigation, using center-pivot or lateral-moving sprinklers, has the potential for a much more equal and controlled distribution pattern. Drip irrigation is the most expensive and least-used type, but offers the ability to deliver water to plant roots with minimal losses. However, drip irrigation is increasingly affordable, especially for the home gardener and in light of rising water rates. Using drip irrigation methods can save up to 30,000 gallons of water per year when replacing irrigation systems that spray in all directions. There are also cheap effective methods similar to drip irrigation such as the use of soaking hoses that can even be submerged in the growing medium to eliminate evaporation.

As changing irrigation systems can be a costly undertaking, conservation efforts often concentrate on maximizing the efficiency of the existing system. This may include chiselling compacted soils, creating furrow dikes to prevent runoff, and using soil moisture and rainfall sensors to optimize irrigation schedules. Usually large gains in efficiency are possible through measurement and more effective management of the existing irrigation system. The 2011 UNEP Green Economy Report notes that "[i]mproved soil organic matter from the use of green manures, mulching, and recycling of crop residues and animal manure increases the water holding capacity of soils and their ability to absorb water during torrential rains", which is a way to optimize the use of rainfall and irrigation during dry periods in the season.

As seen in China, plastic mulch also has the potential to conserve water in agricultural practices. The "mulch" is really a thin sheet of plastic that is placed over the soil. There are holes in the plastic for the plants to grow through. Some studies have shown that plastic mulch conserves water by reducing the evaporation of soil moisture, however, there haven't been enough applied studies to determine the total water savings that this practice may bring about.

Water reuse

Water shortage has become an increasingly difficult problem to manage. More than 40% of the world's population live in a region where the demand for water exceeds its supply. The imbalance between supply and demand, along with persisting issues such as climate change and population growth, has made water reuse a necessary method for conserving water. There are a variety of methods used in the treatment of waste water to ensure that it is safe to use for irrigation of food crops and/or drinking water.

Seawater desalination requires more energy than the desalination of fresh water. Despite this, many seawater desalination plants have been built in response to water shortages around the world. This makes it necessary to evaluate the impacts of seawater desalination and to find ways to improve desalination technology. Current research involves the use of experiments to determine the most effective and least energy intensive methods of desalination.

Sand filtration is another method used to treat water. Recent studies show that sand filtration needs further improvements, but it is approaching optimization with its effectiveness at removing pathogens from water. Sand filtration is very effective at removing protozoa and bacteria, but struggles with removing viruses. Large-scale sand filtration facilities also require large surface areas to accommodate them.

The removal of pathogens from recycled water is of high priority because wastewater always contains pathogens capable of infecting humans. The levels of pathogenic viruses have to be reduced to a certain level in order for recycled water to not pose a threat to human populations. Further research is necessary to determine more accurate methods of assessing the level of pathogenic viruses in treated wastewater.

Problem areas

Wasting of water

Leaking garden hose bib

Wasting of water is the flip side of water conservation and, in household applications, it means causing or permitting discharge of water without any practical purpose. Inefficient water use is also considered wasteful. By EPA estimate, household leaks in the US can waste approximately 900 billion gallons (3.4 billion cubic meters) of water annually nationwide. Generally, water management agencies are reluctant or unwilling to give a concrete definition to the somewhat fuzzy concept of water waste.

However, definition of water waste is often given in local drought emergency ordinances. One example refers to any acts or omissions, whether willful or negligent, that are “causing or permitting water to leak, discharge, flow or run to waste into any gutter, sanitary sewer, watercourse or public or private storm drain, or to any adjacent property, from any tap, hose, faucet, pipe, sprinkler, pond, pool, waterway, fountain or nozzle.”. In this example, the city code also clarifies that “in the case of washing, “discharge,” “flow” or “run to waste” means that water in excess of that necessary to wash, wet or clean the dirty or dusty object, such as an automobile, sidewalk, or parking area, flows to waste.

Water utilities (and other media sources) often provide listings of wasteful water-use practices and prohibitions of wasteful uses. Examples include utilities in San Antonio, Texas. Las Vegas, Nevada, California Water Service company in California, and City of San Diego, California. The City of Palo Alto in California enforces permanent water use restrictions on wasteful practices such as leaks, runoff, irrigating during and immediately after rainfall, and use of potable water when non-potable water is available. Similar restrictions are in effect in the State of Victoria, Australia. Temporary water use bans (also known as "hosepipe bans") are used in England, Scotland, Wales and Northern Ireland.

Strictly speaking, water that is discharged into the sewer, or directly to the environment is not wasted or lost. It remains within the hydrologic cycle and returns to the land surface and surface water bodies as precipitation. However, in many cases, the source of the water is at a significant distance from the return point and may be in a different catchment. The separation between extraction point and return point can represent significant environmental degradation in the watercourse and riparian strip. What is "wasted" is the community's supply of water that was captured, stored, transported and treated to drinking quality standards. Efficient use of water saves the expense of water supply provision and leaves more fresh water in lakes, rivers and aquifers for other users and also for supporting ecosystems.

A concept that is closely related to water wasting is "water-use efficiency." Water use is considered inefficient if the same purpose of its use can be accomplished with less water. Technical efficiency derives from engineering practice where it is typically used to describe the ratio of output to input and is useful in comparing various products and processes. For example, one showerhead would be considered more efficient than another if it could accomplish the same purpose (i.e., of showering) by using less water or other inputs (e.g., lower water pressure). Urinals are more efficient than toilet stalls in public restrooms for men or boys in situations where the user only needs to urinate; and although this is a natural function, urinals offer considerably less privacy. The technical efficiency concept is not useful in making decisions of investing money (or resources) in water conservation measures unless the inputs and outputs are measured in value terms. This expression of efficiency is referred to as economic efficiency and is incorporated into the concept of water conservation.

Operator (computer programming)

From Wikipedia, the free encyclopedia https://en.wikipedia.org/wiki/Operator_(computer_programmin...