It aims to provide a comprehensive overview of relevant theories, concepts, and empirical studies.
The background outlines the broader research area, introduces the research problem, and explains the significance and rationale for the study.
The emphasis is on evaluating and comparing different studies.
Its primary focus is on explaining the research problem’s significance and relevance and setting the study’s stage.
It follows a structured and organized format, synthesizing the existing literature chronologically.
It provides a brief overview of the research topic and the significance of the study.
When writing a background section for a research paper, you can follow these three steps to ensure a clear and compelling presentation:
Following these steps, you can create a well-structured and coherent background section that establishes your research’s context, significance, and rationale. Remember to provide sufficient background information and be concise yet informative in your presentation.
Here are a few tips to help you avoid common mistakes when writing background paragraphs:
By following these tips, you can enhance the quality of your background section, ensuring that it effectively sets the stage for your research and engages the reader from the beginning of your paper.
To write the background of a research paper, you must understand the overall structure and know exactly how this section should look.
Let’s see an excellent example of a background section for a research paper on the topic of “The Impact of Social Media on Mental Health”:
“The rapid rise of social media platforms in recent years has transformed how people communicate, connect, and share information. Platforms such as Facebook, Instagram, Twitter, and Snapchat have become integral parts of daily life for millions of individuals worldwide.
While social media offers numerous benefits, including increased social connectivity and access to diverse perspectives, concerns have been raised regarding its potential impact on mental health.
Numerous studies have investigated the relationship between social media use and mental health outcomes, focusing on depression, anxiety, and body image dissatisfaction.
This study seeks to contribute to the existing knowledge by employing a longitudinal design and examining a broad range of mental health outcomes among a diverse sample of adults aged 18-45.
Research has shown that excessive use of social media and constant exposure to carefully curated and idealized representations of others’ lives can contribute to feelings of inadequacy, social comparison, and low self-esteem.
Additionally, cyberbullying has emerged as a significant concern, as individuals may experience harassment, negative comments, and exclusion within the online environment”.
You have to be very concise and clear to write a background paragraph. Remember that it often serves as the first point of contact between your research and the reader. As a result, the background section has to focus on the study, explaining the significance and relevance of the research problem.
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Research background is a brief outline of the most important studies that have been conducted so far presented in a chronological order. Research background part in introduction chapter can be also headed ‘Background of the Study.” Research background should also include a brief discussion of major theories and models related to the research problem.
Specifically, when writing research background you can discuss major theories and models related to your research problem in a chronological order to outline historical developments in the research area. When writing research background, you also need to demonstrate how your research relates to what has been done so far in the research area.
Research background is written after the literature review. Therefore, literature review has to be the first and the longest stage in the research process, even before the formulation of research aims and objectives, right after the selection of the research area. Once the research area is selected, the literature review is commenced in order to identify gaps in the research area.
Research aims and objectives need to be closely associated with the elimination of this gap in the literature. The main difference between background of the study and literature review is that the former only provides general information about what has been done so far in the research area, whereas the latter elaborates and critically reviews previous works.
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The methods section describes actions taken to investigate a research problem and the rationale for the application of specific procedures or techniques used to identify, select, process, and analyze information applied to understanding the problem, thereby, allowing the reader to critically evaluate a study’s overall validity and reliability. The methodology section of a research paper answers two main questions: How was the data collected or generated? And, how was it analyzed? The writing should be direct and precise and always written in the past tense.
Kallet, Richard H. "How to Write the Methods Section of a Research Paper." Respiratory Care 49 (October 2004): 1229-1232.
You must explain how you obtained and analyzed your results for the following reasons:
Bem, Daryl J. Writing the Empirical Journal Article. Psychology Writing Center. University of Washington; Denscombe, Martyn. The Good Research Guide: For Small-Scale Social Research Projects . 5th edition. Buckingham, UK: Open University Press, 2014; Lunenburg, Frederick C. Writing a Successful Thesis or Dissertation: Tips and Strategies for Students in the Social and Behavioral Sciences . Thousand Oaks, CA: Corwin Press, 2008.
I. Groups of Research Methods
There are two main groups of research methods in the social sciences:
II. Content
The introduction to your methodology section should begin by restating the research problem and underlying assumptions underpinning your study. This is followed by situating the methods you used to gather, analyze, and process information within the overall “tradition” of your field of study and within the particular research design you have chosen to study the problem. If the method you choose lies outside of the tradition of your field [i.e., your review of the literature demonstrates that the method is not commonly used], provide a justification for how your choice of methods specifically addresses the research problem in ways that have not been utilized in prior studies.
The remainder of your methodology section should describe the following:
In addition, an effectively written methodology section should:
NOTE: Once you have written all of the elements of the methods section, subsequent revisions should focus on how to present those elements as clearly and as logically as possibly. The description of how you prepared to study the research problem, how you gathered the data, and the protocol for analyzing the data should be organized chronologically. For clarity, when a large amount of detail must be presented, information should be presented in sub-sections according to topic. If necessary, consider using appendices for raw data.
ANOTHER NOTE: If you are conducting a qualitative analysis of a research problem , the methodology section generally requires a more elaborate description of the methods used as well as an explanation of the processes applied to gathering and analyzing of data than is generally required for studies using quantitative methods. Because you are the primary instrument for generating the data [e.g., through interviews or observations], the process for collecting that data has a significantly greater impact on producing the findings. Therefore, qualitative research requires a more detailed description of the methods used.
YET ANOTHER NOTE: If your study involves interviews, observations, or other qualitative techniques involving human subjects , you may be required to obtain approval from the university's Office for the Protection of Research Subjects before beginning your research. This is not a common procedure for most undergraduate level student research assignments. However, i f your professor states you need approval, you must include a statement in your methods section that you received official endorsement and adequate informed consent from the office and that there was a clear assessment and minimization of risks to participants and to the university. This statement informs the reader that your study was conducted in an ethical and responsible manner. In some cases, the approval notice is included as an appendix to your paper.
III. Problems to Avoid
Irrelevant Detail The methodology section of your paper should be thorough but concise. Do not provide any background information that does not directly help the reader understand why a particular method was chosen, how the data was gathered or obtained, and how the data was analyzed in relation to the research problem [note: analyzed, not interpreted! Save how you interpreted the findings for the discussion section]. With this in mind, the page length of your methods section will generally be less than any other section of your paper except the conclusion.
Unnecessary Explanation of Basic Procedures Remember that you are not writing a how-to guide about a particular method. You should make the assumption that readers possess a basic understanding of how to investigate the research problem on their own and, therefore, you do not have to go into great detail about specific methodological procedures. The focus should be on how you applied a method , not on the mechanics of doing a method. An exception to this rule is if you select an unconventional methodological approach; if this is the case, be sure to explain why this approach was chosen and how it enhances the overall process of discovery.
Problem Blindness It is almost a given that you will encounter problems when collecting or generating your data, or, gaps will exist in existing data or archival materials. Do not ignore these problems or pretend they did not occur. Often, documenting how you overcame obstacles can form an interesting part of the methodology. It demonstrates to the reader that you can provide a cogent rationale for the decisions you made to minimize the impact of any problems that arose.
Literature Review Just as the literature review section of your paper provides an overview of sources you have examined while researching a particular topic, the methodology section should cite any sources that informed your choice and application of a particular method [i.e., the choice of a survey should include any citations to the works you used to help construct the survey].
It’s More than Sources of Information! A description of a research study's method should not be confused with a description of the sources of information. Such a list of sources is useful in and of itself, especially if it is accompanied by an explanation about the selection and use of the sources. The description of the project's methodology complements a list of sources in that it sets forth the organization and interpretation of information emanating from those sources.
Azevedo, L.F. et al. "How to Write a Scientific Paper: Writing the Methods Section." Revista Portuguesa de Pneumologia 17 (2011): 232-238; Blair Lorrie. “Choosing a Methodology.” In Writing a Graduate Thesis or Dissertation , Teaching Writing Series. (Rotterdam: Sense Publishers 2016), pp. 49-72; Butin, Dan W. The Education Dissertation A Guide for Practitioner Scholars . Thousand Oaks, CA: Corwin, 2010; Carter, Susan. Structuring Your Research Thesis . New York: Palgrave Macmillan, 2012; Kallet, Richard H. “How to Write the Methods Section of a Research Paper.” Respiratory Care 49 (October 2004):1229-1232; Lunenburg, Frederick C. Writing a Successful Thesis or Dissertation: Tips and Strategies for Students in the Social and Behavioral Sciences . Thousand Oaks, CA: Corwin Press, 2008. Methods Section. The Writer’s Handbook. Writing Center. University of Wisconsin, Madison; Rudestam, Kjell Erik and Rae R. Newton. “The Method Chapter: Describing Your Research Plan.” In Surviving Your Dissertation: A Comprehensive Guide to Content and Process . (Thousand Oaks, Sage Publications, 2015), pp. 87-115; What is Interpretive Research. Institute of Public and International Affairs, University of Utah; Writing the Experimental Report: Methods, Results, and Discussion. The Writing Lab and The OWL. Purdue University; Methods and Materials. The Structure, Format, Content, and Style of a Journal-Style Scientific Paper. Department of Biology. Bates College.
Statistical Designs and Tests? Do Not Fear Them!
Don't avoid using a quantitative approach to analyzing your research problem just because you fear the idea of applying statistical designs and tests. A qualitative approach, such as conducting interviews or content analysis of archival texts, can yield exciting new insights about a research problem, but it should not be undertaken simply because you have a disdain for running a simple regression. A well designed quantitative research study can often be accomplished in very clear and direct ways, whereas, a similar study of a qualitative nature usually requires considerable time to analyze large volumes of data and a tremendous burden to create new paths for analysis where previously no path associated with your research problem had existed.
To locate data and statistics, GO HERE .
Knowing the Relationship Between Theories and Methods
There can be multiple meaning associated with the term "theories" and the term "methods" in social sciences research. A helpful way to delineate between them is to understand "theories" as representing different ways of characterizing the social world when you research it and "methods" as representing different ways of generating and analyzing data about that social world. Framed in this way, all empirical social sciences research involves theories and methods, whether they are stated explicitly or not. However, while theories and methods are often related, it is important that, as a researcher, you deliberately separate them in order to avoid your theories playing a disproportionate role in shaping what outcomes your chosen methods produce.
Introspectively engage in an ongoing dialectic between the application of theories and methods to help enable you to use the outcomes from your methods to interrogate and develop new theories, or ways of framing conceptually the research problem. This is how scholarship grows and branches out into new intellectual territory.
Reynolds, R. Larry. Ways of Knowing. Alternative Microeconomics . Part 1, Chapter 3. Boise State University; The Theory-Method Relationship. S-Cool Revision. United Kingdom.
Methods and the Methodology
Do not confuse the terms "methods" and "methodology." As Schneider notes, a method refers to the technical steps taken to do research . Descriptions of methods usually include defining and stating why you have chosen specific techniques to investigate a research problem, followed by an outline of the procedures you used to systematically select, gather, and process the data [remember to always save the interpretation of data for the discussion section of your paper].
The methodology refers to a discussion of the underlying reasoning why particular methods were used . This discussion includes describing the theoretical concepts that inform the choice of methods to be applied, placing the choice of methods within the more general nature of academic work, and reviewing its relevance to examining the research problem. The methodology section also includes a thorough review of the methods other scholars have used to study the topic.
Bryman, Alan. "Of Methods and Methodology." Qualitative Research in Organizations and Management: An International Journal 3 (2008): 159-168; Schneider, Florian. “What's in a Methodology: The Difference between Method, Methodology, and Theory…and How to Get the Balance Right?” PoliticsEastAsia.com. Chinese Department, University of Leiden, Netherlands.
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Introduction.
The background and history section of your dissertation highlights the empirical foundations of the topic that you have chosen and this can comprise of five or six per cent of the total word limit.
The ‘background’ section or chapter is often considered the ‘other half’ of the introduction section or chapter and it may be incorporated within it or as a separate chapter. While the introduction deals with the thematic structure of your work, the background deals with the academic ‘history’ of your work.
The purpose of a dissertation background/history section is to give the reader the relevant facts about your chosen dissertation topic so that they understand the material or case that you will write about later and how it links to your theoretical question.
It aims to contextualise your study and to explain its relevance. The background chapter will explain how your work adds to and builds upon existing academic studies.
In this chapter, it is important to select information carefully. It is tempting to write all you know about a subject, but it is more important to tell the reader what they need to know before they continue reading your dissertation.
This section doesn’t just provide the general context, but it also directs the readers’ attention to the empirical details through which your research topic and questions are lived and made relevant. This will illustrate the need for, and the importance of, your research.
It’s important your work is viewed as academically contextualised, and so the background chapter will show your grounding in academic theory, and how your research will take a fresh look at an issue.
It first needs to explain the general background to the existing research in the area that you are studying by mentioning previous studies that have been written on the subject. You may not find work that very specifically addresses your topic, but you will find literature that is comparable or is linked to it in some way.
Secondly, you need to explain how your study builds upon the existing studies by offering something new. The background chapter is a rationale for your study and in the same way that the introduction introduces the ‘key themes’ of the chapters, the background acts as a precursor to the literature review and (depending upon the subject matter) the methodology.
There are three simple overlapping concepts to keep in mind when writing your background or history section.
You may also use this review to implicitly reveal what has drawn you to the topic in the first place. Doing this well will help convince the reader that your interest in the topic is justified and that you are likely to sustain that interest over the time required to complete the project.
As with the theoretical review, the historical and background section must be precise and measured. A piece that is too passionate, too political, or too lengthy a historical review may cause some readers to lose focus or question your capacity to be detached and analytical.
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If you require assistance to write the background section of your dissertation, you may want to consider our helpful service which is a great way to get a head start on your work.
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The rationale of the study is the justification for taking on a given study. It explains the reason the study was conducted or should be conducted. This means the study rationale should explain to the reader or examiner why the study is/was necessary. It is also sometimes called the “purpose” or “justification” of a study. While this is not difficult to grasp in itself, you might wonder how the rationale of the study is different from your research question or from the statement of the problem of your study, and how it fits into the rest of your thesis or research paper.
The rationale of the study links the background of the study to your specific research question and justifies the need for the latter on the basis of the former. In brief, you first provide and discuss existing data on the topic, and then you tell the reader, based on the background evidence you just presented, where you identified gaps or issues and why you think it is important to address those. The problem statement, lastly, is the formulation of the specific research question you choose to investigate, following logically from your rationale, and the approach you are planning to use to do that.
How to write a rationale for a research paper , how do you justify the need for a research study.
The basis for writing a research rationale is preliminary data or a clear description of an observation. If you are doing basic/theoretical research, then a literature review will help you identify gaps in current knowledge. In applied/practical research, you base your rationale on an existing issue with a certain process (e.g., vaccine proof registration) or practice (e.g., patient treatment) that is well documented and needs to be addressed. By presenting the reader with earlier evidence or observations, you can (and have to) convince them that you are not just repeating what other people have already done or said and that your ideas are not coming out of thin air.
Once you have explained where you are coming from, you should justify the need for doing additional research–this is essentially the rationale of your study. Finally, when you have convinced the reader of the purpose of your work, you can end your introduction section with the statement of the problem of your research that contains clear aims and objectives and also briefly describes (and justifies) your methodological approach.
The author can present the study rationale both before and after the research is conducted.
Although every study rationale is different and discusses different specific elements of a study’s method or approach, there are some elements that should be included to write a good rationale. Make sure to touch on the following:
There are different types of limitations that you can use to justify the need for your study. In applied/practical research, the justification for investigating something is always that an existing process/practice has a problem or is not satisfactory. Let’s say, for example, that people in a certain country/city/community commonly complain about hospital care on weekends (not enough staff, not enough attention, no decisions being made), but you looked into it and realized that nobody ever investigated whether these perceived problems are actually based on objective shortages/non-availabilities of care or whether the lower numbers of patients who are treated during weekends are commensurate with the provided services.
In this case, “lack of data” is your justification for digging deeper into the problem. Or, if it is obvious that there is a shortage of staff and provided services on weekends, you could decide to investigate which of the usual procedures are skipped during weekends as a result and what the negative consequences are.
In basic/theoretical research, lack of knowledge is of course a common and accepted justification for additional research—but make sure that it is not your only motivation. “Nobody has ever done this” is only a convincing reason for a study if you explain to the reader why you think we should know more about this specific phenomenon. If there is earlier research but you think it has limitations, then those can usually be classified into “methodological”, “contextual”, and “conceptual” limitations. To identify such limitations, you can ask specific questions and let those questions guide you when you explain to the reader why your study was necessary:
Let’s look at an example from one of our earlier articles on the statement of the problem to clarify how your rationale fits into your introduction section. This is a very short introduction for a practical research study on the challenges of online learning. Your introduction might be much longer (especially the context/background section), and this example does not contain any sources (which you will have to provide for all claims you make and all earlier studies you cite)—but please pay attention to how the background presentation , rationale, and problem statement blend into each other in a logical way so that the reader can follow and has no reason to question your motivation or the foundation of your research.
Since the beginning of the Covid pandemic, most educational institutions around the world have transitioned to a fully online study model, at least during peak times of infections and social distancing measures. This transition has not been easy and even two years into the pandemic, problems with online teaching and studying persist (reference needed) .
While the increasing gap between those with access to technology and equipment and those without access has been determined to be one of the main challenges (reference needed) , others claim that online learning offers more opportunities for many students by breaking down barriers of location and distance (reference needed) .
Since teachers and students cannot wait for circumstances to go back to normal, the measures that schools and universities have implemented during the last two years, their advantages and disadvantages, and the impact of those measures on students’ progress, satisfaction, and well-being need to be understood so that improvements can be made and demographics that have been left behind can receive the support they need as soon as possible.
To identify what changes in the learning environment were considered the most challenging and how those changes relate to a variety of student outcome measures, we conducted surveys and interviews among teachers and students at ten institutions of higher education in four different major cities, two in the US (New York and Chicago), one in South Korea (Seoul), and one in the UK (London). Responses were analyzed with a focus on different student demographics and how they might have been affected differently by the current situation.
In a research article bound for journal publication, your rationale should not be longer than a few sentences (no longer than one brief paragraph). A dissertation or thesis usually allows for a longer description; depending on the length and nature of your document, this could be up to a couple of paragraphs in length. A completely novel or unconventional approach might warrant a longer and more detailed justification than an approach that slightly deviates from well-established methods and approaches.
Now that you know how to write the rationale of the study for a research proposal or paper, you should make use of Wordvice AI’s free AI Grammar Checker , or receive professional academic proofreading services from Wordvice, including research paper editing services and manuscript editing services to polish your submitted research documents.
You can also find many more articles, for example on writing the other parts of your research paper , on choosing a title , or on making sure you understand and adhere to the author instructions before you submit to a journal, on the Wordvice academic resources pages.
Purpose of a white paper, how to write a white paper, the bottom line.
Adam Hayes, Ph.D., CFA, is a financial writer with 15+ years Wall Street experience as a derivatives trader. Besides his extensive derivative trading expertise, Adam is an expert in economics and behavioral finance. Adam received his master's in economics from The New School for Social Research and his Ph.D. from the University of Wisconsin-Madison in sociology. He is a CFA charterholder as well as holding FINRA Series 7, 55 & 63 licenses. He currently researches and teaches economic sociology and the social studies of finance at the Hebrew University in Jerusalem.
Thomas J Catalano is a CFP and Registered Investment Adviser with the state of South Carolina, where he launched his own financial advisory firm in 2018. Thomas' experience gives him expertise in a variety of areas including investments, retirement, insurance, and financial planning.
Investopedia / Michela Buttignol
A white paper is an informational document issued by a company or not-for-profit organization to promote or highlight the features of a solution, product, or service that it offers or plans to offer.
White papers are also used as a method of presenting government policies and legislation and gauging public opinion.
White papers are sales and marketing documents used to entice or persuade potential customers to learn more about a particular product, service, technology, or methodology.
White papers are commonly designed for business-to-business (B2B) marketing purposes between a manufacturer and a wholesaler , or between a wholesaler and a retailer. It can provide an in-depth report or guide about a specific product or topic and is meant to educate its readers.
The facts presented in white papers are often backed by research and statistics from reliable sources and can include charts, graphs, tables, and other ways of visualizing data. A white paper can communicate an organization’s philosophy or present research findings related to an industry.
A startup , large corporation, or government agency will use white papers differently. There are three main types of white papers: backgrounders, numbered lists, and problem/solution white papers.
Backgrounders detail the technical features of a new product or service. Designed to simplify complicated technical information, they are used to:
Numbered lists highlight the key takeaways of a new product or service, and are often formatted with headings and bullet points such as the following familiar format:
Problem/solution papers identify specific problems faced by potential customers and suggest a data-driven argument about how a featured product or service provides a solution to:
White papers differ from other marketing materials, such as brochures. Brochures and traditional marketing materials might be flashy and obvious, but a white paper is intended to provide persuasive and factual evidence that solves a problem or challenge.
White papers are commonly at least 2,500 words in length and written in an academic style.
A white paper should provide well-researched information that is not found with a simple Internet search and has a compelling narrative to keep the reader’s attention. The author of a white paper should:
All of the documents listed below, publicly available on Microsoft’s website, focus on aspects of the company’s suite of cloud services. In contrast with brochures, these white papers don’t have a clear sales pitch. Instead, they dive into relevant topics, such as cloud security, hybrid clouds, and the economic benefits of adopting cloud computing.
Cryptocurrencies have also been known to publish white papers during initial coin offerings (ICOs) and frequently issued white papers to entice users and “investors” to their projects.
Bitcoin famously launched a few months after the pseudonymous Satoshi Nakamoto issued its famous white paper online in October 2008.
White papers may have developed from the use of “Blue Papers” in 19th century Britain, where a Parliament report cover was blue. When a topic for the government was less serious, the blue cover was discarded and published with white covers. These reports were called White Papers. In the United States, the use of government white papers often means a background report or guidance on a specific issue.
A white paper is an informational document issued by a company, government agency, or not-for-profit organization to promote the features of a solution, product, or service that it offers or plans to offer. The facts presented in white papers are often backed by research and statistics from reliable sources and are commonly written in one of three formats: backgrounders, numbered lists, and problem/solution papers.
Bitcoin.org. " Bitcoin: A Peer-to-Peer Electronic Cash System ."
Michigan State University. " Finding British Parliamentary Papers in the M.S.U. Libraries, Collections Guide No. 6 (Advanced): Parliamentary, or Sessional Papers--Discussion ."
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We, the APA Style team, are not robots. We can all pass a CAPTCHA test , and we know our roles in a Turing test . And, like so many nonrobot human beings this year, we’ve spent a fair amount of time reading, learning, and thinking about issues related to large language models, artificial intelligence (AI), AI-generated text, and specifically ChatGPT . We’ve also been gathering opinions and feedback about the use and citation of ChatGPT. Thank you to everyone who has contributed and shared ideas, opinions, research, and feedback.
In this post, I discuss situations where students and researchers use ChatGPT to create text and to facilitate their research, not to write the full text of their paper or manuscript. We know instructors have differing opinions about how or even whether students should use ChatGPT, and we’ll be continuing to collect feedback about instructor and student questions. As always, defer to instructor guidelines when writing student papers. For more about guidelines and policies about student and author use of ChatGPT, see the last section of this post.
If you’ve used ChatGPT or other AI tools in your research, describe how you used the tool in your Method section or in a comparable section of your paper. For literature reviews or other types of essays or response or reaction papers, you might describe how you used the tool in your introduction. In your text, provide the prompt you used and then any portion of the relevant text that was generated in response.
Unfortunately, the results of a ChatGPT “chat” are not retrievable by other readers, and although nonretrievable data or quotations in APA Style papers are usually cited as personal communications , with ChatGPT-generated text there is no person communicating. Quoting ChatGPT’s text from a chat session is therefore more like sharing an algorithm’s output; thus, credit the author of the algorithm with a reference list entry and the corresponding in-text citation.
When prompted with “Is the left brain right brain divide real or a metaphor?” the ChatGPT-generated text indicated that although the two brain hemispheres are somewhat specialized, “the notation that people can be characterized as ‘left-brained’ or ‘right-brained’ is considered to be an oversimplification and a popular myth” (OpenAI, 2023).
OpenAI. (2023). ChatGPT (Mar 14 version) [Large language model]. https://chat.openai.com/chat
You may also put the full text of long responses from ChatGPT in an appendix of your paper or in online supplemental materials, so readers have access to the exact text that was generated. It is particularly important to document the exact text created because ChatGPT will generate a unique response in each chat session, even if given the same prompt. If you create appendices or supplemental materials, remember that each should be called out at least once in the body of your APA Style paper.
When given a follow-up prompt of “What is a more accurate representation?” the ChatGPT-generated text indicated that “different brain regions work together to support various cognitive processes” and “the functional specialization of different regions can change in response to experience and environmental factors” (OpenAI, 2023; see Appendix A for the full transcript).
The in-text citations and references above are adapted from the reference template for software in Section 10.10 of the Publication Manual (American Psychological Association, 2020, Chapter 10). Although here we focus on ChatGPT, because these guidelines are based on the software template, they can be adapted to note the use of other large language models (e.g., Bard), algorithms, and similar software.
The reference and in-text citations for ChatGPT are formatted as follows:
Let’s break that reference down and look at the four elements (author, date, title, and source):
Author: The author of the model is OpenAI.
Date: The date is the year of the version you used. Following the template in Section 10.10, you need to include only the year, not the exact date. The version number provides the specific date information a reader might need.
Title: The name of the model is “ChatGPT,” so that serves as the title and is italicized in your reference, as shown in the template. Although OpenAI labels unique iterations (i.e., ChatGPT-3, ChatGPT-4), they are using “ChatGPT” as the general name of the model, with updates identified with version numbers.
The version number is included after the title in parentheses. The format for the version number in ChatGPT references includes the date because that is how OpenAI is labeling the versions. Different large language models or software might use different version numbering; use the version number in the format the author or publisher provides, which may be a numbering system (e.g., Version 2.0) or other methods.
Bracketed text is used in references for additional descriptions when they are needed to help a reader understand what’s being cited. References for a number of common sources, such as journal articles and books, do not include bracketed descriptions, but things outside of the typical peer-reviewed system often do. In the case of a reference for ChatGPT, provide the descriptor “Large language model” in square brackets. OpenAI describes ChatGPT-4 as a “large multimodal model,” so that description may be provided instead if you are using ChatGPT-4. Later versions and software or models from other companies may need different descriptions, based on how the publishers describe the model. The goal of the bracketed text is to briefly describe the kind of model to your reader.
Source: When the publisher name and the author name are the same, do not repeat the publisher name in the source element of the reference, and move directly to the URL. This is the case for ChatGPT. The URL for ChatGPT is https://chat.openai.com/chat . For other models or products for which you may create a reference, use the URL that links as directly as possible to the source (i.e., the page where you can access the model, not the publisher’s homepage).
You may have noticed the confidence with which ChatGPT described the ideas of brain lateralization and how the brain operates, without citing any sources. I asked for a list of sources to support those claims and ChatGPT provided five references—four of which I was able to find online. The fifth does not seem to be a real article; the digital object identifier given for that reference belongs to a different article, and I was not able to find any article with the authors, date, title, and source details that ChatGPT provided. Authors using ChatGPT or similar AI tools for research should consider making this scrutiny of the primary sources a standard process. If the sources are real, accurate, and relevant, it may be better to read those original sources to learn from that research and paraphrase or quote from those articles, as applicable, than to use the model’s interpretation of them.
We’ve also received a number of other questions about ChatGPT. Should students be allowed to use it? What guidelines should instructors create for students using AI? Does using AI-generated text constitute plagiarism? Should authors who use ChatGPT credit ChatGPT or OpenAI in their byline? What are the copyright implications ?
On these questions, researchers, editors, instructors, and others are actively debating and creating parameters and guidelines. Many of you have sent us feedback, and we encourage you to continue to do so in the comments below. We will also study the policies and procedures being established by instructors, publishers, and academic institutions, with a goal of creating guidelines that reflect the many real-world applications of AI-generated text.
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Research Article
Roles Conceptualization, Data curation, Investigation, Methodology, Project administration, Resources, Supervision, Validation, Visualization, Writing – original draft, Writing – review & editing
* E-mail: [email protected] , [email protected]
Affiliation Paleotechnic., Paris, France
Roles Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Project administration, Software, Validation, Visualization, Writing – original draft, Writing – review & editing
Affiliation Univ. Grenoble Alpes, INRAE, CNRS, IRD, Grenoble INP, IGE, Grenoble, France
Roles Conceptualization, Investigation, Methodology, Software, Visualization
Affiliation Sicame Group, Arnac-Pompadour, France
Roles Conceptualization, Investigation, Methodology, Validation, Writing – review & editing
Affiliation CEDETE—Centre d’études sur le Développement des Territoires et l’Environnement, Université d’Orléans, Orléans, France
Roles Conceptualization, Investigation, Methodology, Validation
Roles Conceptualization, Investigation, Methodology, Visualization
Affiliation AtoutsCarto, Bourges, France
Roles Methodology, Project administration
Affiliation Verilux International, Brienon-sur-Armançon, France
Roles Conceptualization, Investigation, Validation, Writing – review & editing
Roles Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Software, Validation
Roles Conceptualization, Investigation, Methodology, Supervision, Validation
The Step Pyramid of Djoser in Saqqara, Egypt, is considered the oldest of the seven monumental pyramids built about 4,500 years ago. From transdisciplinary analysis, it was discovered that a hydraulic lift may have been used to build the pyramid. Based on our mapping of the nearby watersheds, we show that one of the unexplained massive Saqqara structures, the Gisr el-Mudir enclosure, has the features of a check dam with the intent to trap sediment and water. The topography beyond the dam suggests a possible ephemeral lake west of the Djoser complex and water flow inside the ’Dry Moat’ surrounding it. In the southern section of the moat, we show that the monumental linear rock-cut structure consisting of successive, deep compartments combines the technical requirements of a water treatment facility: a settling basin, a retention basin, and a purification system. Together, the Gisr el-Mudir and the Dry Moat’s inner south section work as a unified hydraulic system that improves water quality and regulates flow for practical purposes and human needs. Finally, we identified that the Step Pyramid’s internal architecture is consistent with a hydraulic elevation mechanism never reported before. The ancient architects may have raised the stones from the pyramid centre in a volcano fashion using the sediment-free water from the Dry Moat’s south section. Ancient Egyptians are famous for their pioneering and mastery of hydraulics through canals for irrigation purposes and barges to transport huge stones. This work opens a new line of research: the use of hydraulic force to erect the massive structures built by Pharaohs.
Citation: Landreau X, Piton G, Morin G, Bartout P, Touchart L, Giraud C, et al. (2024) On the possible use of hydraulic force to assist with building the step pyramid of saqqara. PLoS ONE 19(8): e0306690. https://doi.org/10.1371/journal.pone.0306690
Editor: Joe Uziel, Israel Antiquities Authority, ISRAEL
Received: December 7, 2023; Accepted: June 22, 2024; Published: August 5, 2024
Copyright: © 2024 Landreau et al. This is an open access article distributed under the terms of the Creative Commons Attribution License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Data Availability: All relevant data are within the manuscript and its Supporting Information files. The computer codes are available upon request.
Funding: The Sicame Group, The Atoutscarto Company and The Verilux Company provided support in the form of salaries for GM, CG and J-CM, respectively. The specific roles of these authors are articulated in the ‘author contributions’ section.
Competing interests: The authors have read the journal’s policy and have the following competing interests: GM, CG and J-CM are paid employees of The Sicame Group, The Atoutscarto Company and The Verilux Company, respectively. There are no patents, products in development or marketed products associated with this research to declare. This does not alter our adherence to PLOS ONE policies on sharing data and materials.
The funerary complex of King Djoser, built at Saqqara in Egypt around 2680 B.C., is considered a significant milestone in monumental architecture. It is the first to disclose two crucial innovations: a pyramid shape for the pharaoh’s grave and the exclusive use of fully dressed stones for masonry. In practice, it is also revolutionary in the ability to extract and raise stones by millions before stacking them with precision [ 1 ]. Djoser’s complex visible achievements are such that its architect, Vizier, and Great Priest of Ra, Imhotep, was deified by the New Kingdom.
The knowledge and innovations implemented in the Djoser mortuary complex profoundly influenced future developments and were widely perfected throughout the Old Kingdom’s III rd and IV th Dynasties, i . e . circa 2680–2460 B.C. These developments resulted in a substantial increase in the megaliths’ size [ 2 ], leading to pyramids of spectacular dimensions, such as those of the Meidum, Dahshur, and Giza plateaus. In less than 150 years, the average weight of the typical large stones was thus multiplied by ≈8 and went from ≈300 kg for Djoser’s pyramid to more than 2.5 tons for Chephren’s pyramid’s structural blocks [ 3 ]. For the largest lintels, the weight increases by two orders of magnitude, with several blocks of ≈50 – 100 tons for Cheops’ pyramid. On this short timeframe on the scale of human history, Egyptians carried and raised some 25 million tons of stones [ 4 ] to build seven monumental pyramids. Assuming an annual work schedule of 300 days at a rate of 10 hours/day, meaning 450,000 hours spread over less than 150 years, this requires a technical and logistical organization capable, on average, of cutting, moving, and adjusting about 50 tons of stone blocks per hour. Even if one admits that not every pyramid’s blocks are fitted with millimeter precision, the amount of work accomplished is truly remarkable. Interestingly, the pyramids later built in Egypt tended to be smaller with time and never reached the volume of the Old Kingdom’s monumental structures again.
As authentic sources from the working sphere of pyramid architects are currently lacking, no generally accepted wholistic model for pyramid construction exists yet. Although many detailed publications dedicated to pyramid-building procedures have given tangible elements [ 5 , 6 ], they usually explain more recent, better documented, but also smaller pyramids [ 7 ]. These techniques could include ramps, cranes, winches, toggle lifts, hoists, pivots, or a combination of them [ 8 – 10 ]. Studies of the pyramid’s construction sites also revealed a high level of expertise in managing the hydraulic and hydrological environment, such as utilizing waterways to deliver materials, constructing ports and locks, or setting up irrigation systems [ 11 , 12 ]. These achievements have led some scholars to refer to ancient Egypt as an ‘early hydraulic civilization [ 11 ].’ However, there is actually very little multidisciplinary analysis combining the rich archaeological findings on pyramids with other disciplines such as hydrology, hydraulics, geotechnics, paleoclimatology, or civil engineering [ 9 ]. Therefore, the topic of water force in the context of pyramid construction remains insufficiently addressed in the academic literature.
Moreover, a second question accentuates the enigma: the Pharaohs who built these pyramids are missing. Until now, neither written record nor physical evidence reports the discovery of one of the III rd and IV th Dynasties’ Pharaohs. Old Kingdom’s ‘big’ pyramids’ rooms were allegedly plundered [ 13 – 15 ] during the millennia that followed the construction of the pyramids, leaving little evidence behind [ 12 ]. The III rd and IV th Dynasties’ rooms present little or no funerary attributes, such as those observed in other high-dignitary figures’ tombs contemporary to the period [ 16 , 17 ], with no King’s remains found inside. In addition, the walls of the pyramids’ chambers do not exhibit any hieroglyphs, paintings, engravings, or drawings, which would allow us to qualify them as funerary with certainty. Despite this lack of evidence, many authors [ 18 ] still support that these rooms can be attributed to Pharaohs’ burials mainly based on royal cartouches or Kings’ names found elsewhere within the pyramid or nearby temples.
Over the recent years, Dormion & Verd’Hurt [ 19 , 20 ], Hamilton [ 21 – 24 ] or others [ 1 , 25 ] were among the first to consider possible non-funerary functions of pyramids’ internal layouts by pointing out some architectural inconsistencies and highlighting the high degree of complexity of several structures, irrelevant for a burial chamber. Their analysis provided both chambers and gallery systems with a technical dimension, emphasizing a level of engineering on the part of the ancient builders that is quite remarkable and sometimes challenges any apparent explanation. This technical level is at once reflected in the geometry of the rooms and ducts, as well as in the stonework, which includes materials selection, extraction, cutting, and then assembling with exceptional accuracy [ 20 ]. This precision involved several advanced sub-techniques, such as inter-block mortar joint realization [ 26 – 29 ] or stone polishing with flatness and roughness values that reach levels of contemporary know-how. Apart from surfaces and interfaces, the builders’ technical ability is also evident throughout sophisticated mechanical systems set up in the pyramids [ 30 ], as swivel stone flaps’ designs in the Meidum and Bent pyramids [ 21 , 24 ] or tilted portcullises found in the Bent pyramid, as well as at Giza [ 20 ]. These elements suggest that, rather than an aesthetic rendering or a funerary use for these layouts, ancient Egyptians intended technical functions for some walls, tunnels, corridors, shafts, and chambers where more straightforward existing techniques were insufficient.
In summary, the analysis of the pyramids’ construction and the investigation of their internal layouts seem to require more research to provide a wholistic explanation to their purpose. This study aims to provide a fresh look at these topics by applying an alternative, multi-disciplinary, wholistic approach. It revisits the Old Kingdom’s pyramids’ construction methodology and seeks to explain the significance of internal layouts during construction. Based on current archaeological knowledge, we demonstrate that the Saqqara’s topography and the layout of several structures are consistent with the hypothesis that a hydraulic system was used to build the pyramid. The paper is divided into three main sections that analyze the current scientific literature to address the following inquiries: (i) Was the plateau of Saqqara supplied with water? (ii) If so, how was it possibly stored and treated? and (iii) How was it used to build the pyramid? A discussion and some concluding remarks and perspectives follow.
Our study began with the postulate that the larger Cheops’ and Chephren’s pyramids of Giza plateau were the outcomes of technical progress from previous pyramids, with the Step Pyramid as a technological precursor. While many literature studies focus on the construction of Cheops’ pyramid, we found it more relevant to examine the building techniques used for the Step Pyramid first. This would provide insight into the processes used by ancient builders that were later refined in subsequent pyramids. As a first approach, we analyzed potential reasons for the specific building of King Djoser’s Complex on the Saqqara Plateau.
Although detailed measurements of the Nile flood levels have been reported since the V th Dynasty (2480 B.C.) [ 31 – 33 ], there is very little information available about the hydrology of its desert tributaries, known as ’wadis’, in ancient Egypt. Sedimentological evidence of heavy rainfalls and flash floods exists [ 31 , 34 ] but little is known beyond that.
Determining the rainfall regime that the Saqqara region experienced about 4,700 years B.P. is challenging and uncertain. Past studies demonstrated that, from about 11,000 to 5,000 B.P, during the so-called ‘Green Sahara’ period, the whole Sahara was much wetter than today, and the landscape was savannah rather than desert [ 35 , 36 ]. Around 4500–4800 years B.P. too, the Eastern Mediterranean region was wetter than it is now, despite drying up later [ 37 – 39 ]. A range of annual precipitation value of 50–150 mm/year is assumed in the following calculation to perform crude computations of water resource. It covers the range between the >150 mm/year suggested by Kuper & Kropelin [ 40 ] for the end of the Green Sahara period, before the subsequent drier period, during which rainfall decreased to <50 mm/year. The range of variability, i . e . 50 to 150 mm/yr is also consistent with the typical inter-annual rainfall variability observed in the region [ 38 ].
Then, current hydrological monitoring on Egyptian wadis located further to the north and experiencing comparable annual rainfall ( i . e ., 100–200 mm/yr) showed that only 1–3% of this mean annual precipitation was measured as runoff, i.e., surface flows [ 41 ]. This average range is hereafter used for conservative, first-order estimations of available water volume, referred hereafter to as the ‘water resource’. Note that the infrequent, most intense events can reach 50 mm of rainfall and trigger devastating flash floods where the runoff coefficients have been measured up to 30%, i . e ., one order of magnitude higher than the mean annual [ 41 – 43 ]. Note that these water resource and flash flood hydrology estimates neglect that the soils were probably richer in clay and silt just after the Green Sahara period, with several millennia of a wetter climate and savannah landscape [ 35 , 36 ], which would increase the runoff coefficient and available surface water resource in the wadis.
The Saqqara necropolis is located on a limestone plateau on the west bank of the Nile River, about 180 km from the Mediterranean Sea ( Fig 1 ). The entire site lies in the desert, less than two kilometers from the plateau’s edge (elevation 40–55 m ASL— Above Sea Level ), which overlooks the Nile floodplain (height ≈ 20 m ASL). Further to the west, the desert rises gently for about 20 km (hills’ top elevation ≈ 200–300 m ASL).
(Satellite image: Airbus Pléiades, 2021-07-02, reprinted from Airbus D&S SAS library under a CC BY license, with permission from Michael Chemouny, original copyright 2021).
https://doi.org/10.1371/journal.pone.0306690.g001
The reasons behind the construction of the Djoser complex at Saqqara remain unclear. The contribution of economic, socio-political, and religious factors was previously highlighted [ 44 , 45 ], but environmental factors were also possibly influential. In 2020, Wong provided evidence that the climate, geology, and hydrology would have influenced building choices and may have contributed to, or perhaps accelerated, the emergence of stone architecture on the Saqqara plateau [ 37 ].
From a geological standpoint, the layered structure of the limestone at Saqqara was indeed stressed as a favorable factor for excavating large amounts of construction stones [ 46 , 47 ]. These layers, which consist of 30–60 cm thick sand-rich calcareous beds alternated with calcareous clay and marl layers, made it easy to extract the limestone blocks from their parent beds by vertical cuttings, the original thickness being reflected in the building stones’ thickness of Djoser’s complex.
From a hydrological standpoint, the Abusir wadi is considered a second environmental factor that strongly influenced the Early Dynastic development of the Saqqara necropolis at least [ 45 , 48 – 50 ]. The Abusir wadi is the ephemeral stream draining the hills west of Saqqara ( Fig 1 ) . Before this study, academic research mainly focused on the downstream part of the wadi [ 45 , 48 – 50 ], namely the Abusir Lake [ 51 ] located north of Saqqara Plateau. However, the upstream portion has remained undocumented.
In order to analyze the relationships between the Abusir wadi and the Step Pyramid’s construction project, the drainage networks west of the Saqqara area were mapped for the first time to the best of our knowledge, using various satellite imagery ( Fig 1 ) and Digital Elevation Models (see S1 Fig in S2 File ).
A paleo-drainage system can be identified upstream of the Gisr el-Mudir structure as the origin of the Abusir wadi ( Fig 1 , pink line). The boundaries of this runoff system form a catchment area never reported so far, although easily recognizable from the geomorphological imprints of surface paleochannels in the desert and on historical maps [ 52 ]. Although it currently has a 15 km 2 surface area, we cannot rule out the possibility that the drainage divides shifted and changed due to land alterations and aeolian sand deposits over the past 4,500 years.
The current catchment summit is about 110 m ASL, giving the Abusir wadi a 1% average slope over its slightly more than 6 km length. In the field of hydrology, a 1% gradient is described as ‘rather steep’. With such steep slopes, transportation of sand and gravel is expected during flashfloods, which can cause severe downstream damage (scouring or burying of structures, filling of excavations and ponding areas). In comparison, irrigation channels are rather at least ten times less steep (about 0.1%), and the Nile slope is less than 0.01% (less than 200m of elevation gain between Aswan and Cairo).
Reported since the early 1800s, a former tributary to the Nile called the Bahr Bela Ma [ 53 , 54 ] or ‘ Wadi Taflah’ flowed parallel to the Abusir wadi catchment, less than two kilometers south of the Saqqara plateau. From satellite imagery, we identified that the Wadi Taflah arises from a drainage area of almost 400 km 2 and consists of three main branches ( Fig 2 , numbered black dots) still visible from the desert’s geomorphological marks. This network is also visible on the radar imagery provided by Paillou [ 55 ] that can penetrate multiple meters of sand ( S2 Fig in S2 File ). The similarity of the optical and radar drainage patterns confirms the existence and old age of this hydrological network.
https://doi.org/10.1371/journal.pone.0306690.g002
Although no canal was detected from the satellite data, the close proximity of Abusir wadi with the Wadi Taflah ( Fig 2 ) is intriguing and raises the question about a potential ancient, artificial connection between them. According to the 18 th -century maps published by Savary [ 54 ], the Wadi Taflah was ‘closed by an ancient King of Egypt.’ Such a testimony, although imprecise, could suggest the construction of a water diversion by a former ruler. A geophysical investigation could help to find such a structure if existing. The drainage area of Wadi Taflah covers nearly 400 km 2 at an elevation >58 m ASL. This elevation is high enough to allow the diversion of the drainage area toward the Abusir wadi. This would result in an increase in the drained area and associated availability of water resources by a factor of >25 times. Based on the hydrological conditions described in section 2.1, the estimated water resource from Abusir wadi and Wadi Taflah is crudely between 7,500 to 68,000 m 3 /year and 200,000 to 1,800,000 m 3 /year, respectively.
According to the Saqqara topography ( Fig 3 ), the Abusir wadi flowed through the Gisr el-Mudir enclosure before heading north towards the Nile floodplain, where it used to feed an oxbow lake, the Abusir Lake [ 51 ]. With such a localization, the Gisr el-Mudir walls literally dam the Abusir wadi valley’s entire width. The sparse vegetation only growing in the valley bottom upstream of Gisr el-Mudir and not elsewhere in the area evidences this damming and interception of surface and subsurface flows ( Fig 4A , green line). This slight moist area is dominated by plants commonly found in desert margins and wadis, such as Panicum thurgidum and Alhagi graecorum [ 56 ], and is typical of hypodermal flows.
Contour lines extracted from the 1:5,000 topographical map [ 52 ] “Le Caire, sheet H22”.
https://doi.org/10.1371/journal.pone.0306690.g003
a. The Gisr el-Mudir check dam (Satellite image: Airbus Pléiades, 2021-07-02, reprinted from Airbus D&S SAS library under a CC BY license, with permission from Michael Chemouny, original copyright 2021); b.: Digital Elevation Model generated from the 1:5,000 topographical map “Le Caire, sheet H22”.
https://doi.org/10.1371/journal.pone.0306690.g004
Downstream of the Gisr el-Mudir, the Abusir wadi joins the Saqqara Plateau. Its boundaries are defined to the south by an outcropping limestone ridge and to the east by the Sekhemkhet and Djoser’s enclosures ( Fig 3 ).
The landform of this area seems inconsistent with a pure fluvial formation. Instead, the very flat topography on about 2–2.5 km 2 , according to the Saqqara Geophysics Survey Project (SGSP) [ 57 – 60 ] and possibly allowed some ephemeral ponding water which may have resulted in an episodic upper Abusir lake after the most intense rainfalls. However, due to the several-meter deep wind-blown and alluvial sand cover accumulated over the past millennia [ 57 ], the riverbed altitudes during Djoser’s reign are challenging to establish without further investigations, and only broad patterns can be determined from the local topography [ 52 ].
As with many other small wadis, the Early Dynastic hydrology of the Abusir wadi remains largely unknown. According to fluvial sediment analysis in the Abusir Lake area, the Abusir wadi was probably a perennial stream during the Old Kingdom period [ 51 ]. Although the climate is hot and arid nowadays, several studies support a more humid environment during the Old Kingdom [ 34 ] . Multiple strands of evidence indeed suggest that Egypt experienced considerable rainfalls around the reign of Djoser, resulting in frequent flooding and heavy runoffs on the Saqqara Plateau. This climatic feature is supported by sedimentary deposits resulting from flowing water of ‘considerable kinetic force’ contemporary to Djoser’s reign [ 61 , 62 ] . According to Trzciński et al.[ 34 ], the strongly cemented structure L3 found in the Great Trench surrounding the Djoser Complex was due to cyclical watering while the high content of Fe3+ indicates that the region experienced intensive weathering in a warm and humid environment. In 2020, Wong concluded that the ‘ intriguing possibility that the Great Trench that surrounds the Djoser complex may have been filled with water ’ during Djoser’s reign [ 37 ]. If so, this might explain why tombs were built on the northern part of the Saqqara plateau which has a higher altitude [ 45 ] and nothing was constructed inside the Trench until the reign of Userkaf and Unas (V th Dynasty).
3.1 the gisr el-mudir check dam.
Reported at least since the 18 th century [ 63 ] and extensively described within a decade of a geophysical survey by Mathieson et al ., see also [ 45 ] for a summary, the Gisr el-Mudir is a rectangular enclosure located a few hundred meters west of the Djoser’s complex ( Fig 3 , Fig 4A & 4B ). This monumental structure has a footprint of about 360 m x 620 m, i . e ., larger than the Djoser complex (545 m x 277 m). The walls have an estimated volume of >100,000 m 3 (SGSP, 1992–1993 report), meaning about one-third of the Step Pyramid’s volume. Field inspection and geophysical results from the SGSP [ 57 ] found no construction inside except for a couple of more recent, small graves, thus confirming that the enclosure is mainly empty. Moreover, several elements in the building suggest that this structure predated the Step Pyramid’s complex and was tentatively dated to the late II nd or early III rd Dynasty [ 57 , 64 ], which might turn it into the oldest substantial stone structure in Egypt discovered so far.
Before this study, several conflicting theories about the Gisr el-Mudir’s purpose were put forward [ 59 ]: e . g ., an unfinished pyramid complex (but the lack of a central structure made it improbable to be a funerary monument), a guarded fortress [ 65 ] protecting the Saqqara necropolis from nomadic Bedouin incursions, an embankment to raise a monument to a higher level [ 66 ], a celebration arena [ 64 , 67 ], or even a cattle enclosure. However, given the low level of exploratory work afforded to the structure, no generally accepted explanation exists yet, and its purpose has remained more conjectural than substantiated.
In light of the upstream watershed and its transversal position across the Abusir River, the Gisr el-Mudir’s western wall meets the essential criteria of a check dam, i . e ., a dam intending to manage sediment and water fluxes [ 68 , 69 ]. This comparison is particularly striking regarding its cross-section ( Fig 5 ). According to Mathieson et al . [ 59 ], the basic structure of this wall consists of a hollow construction of two rough-hewn limestone masonry skin-walls, ≈3.2 m high, separated by a 15 m interspace filled with three layers of materials extracted from the surrounding desert bedrock [ 70 ] and cunningly arranged. The first layer ( Fig 5 , ‘ A ’ dot) is made of roughly laid local limestone blocks forming a buttress against the inside of the facing blocks. The secondary fill ( B ) comprises coarse sand and medium to large limestone fragments. Then, the third fill ( C ) consists of rough to fine sand and silt, small limestone fragments, and chippings with pebble and flint nodules. Finally, these A, B, and C backfill layers are positioned symmetrically to the median axis of the wall.
Figure adapted from [ 58 ].
https://doi.org/10.1371/journal.pone.0306690.g005
Civil engineering was used during the Old Kingdom to protect settlements from flash floods, such as the Heit el-Ghurab (’Wall of the Crow’) safeguarding the village of the pyramid builders at Giza [ 71 ]. Regarding the Gisr el-Mudir structure, the abovementioned elements strikingly echo the transversal profile and slope protection of another famous Old Kingdom structure: the Sadd el-Kafara dam built on the Wadi al-Garawi , a colossal building found to be contemporary to that of the Gisr el-Mudir [ 72 – 74 ]. Both structures present the technical signature of zoned earthen dams: a wide embankment made of a central impervious core surrounded by transition filters, i . e ., filling material with coarser grain size, preventing erosion, migration, and potential piping of the core fine material due to seepage. The semi-dressed limestone walls stabilized the inner material and protected it against erosion when water flowed against and above the dam. Both dams have much broader profiles than modern dams. This oversizing could be due to the unavailability of contemporary compaction systems or an empirical and conservative structural design. They both have narrower cores of fine material at the bottom of the dam than at their crest, contradicting modern design [ 75 ]. This can be attributed to the construction phasing that would have started by raising the sidewalls buttressed against the coarse and intermediate filling ( B and C fills in Fig 5 ), followed by a phase of filling the wide core with finer, compacted material [ 72 ].
Finally, the eastern wall’s north-south profile ( Fig 6 , line A-B ) presents a parabolic profile relevant to guide the flows to the basin’s center formed by Gisr el-Mudir. This guidance would have prevented the dam failure by outflanking during flooding events when the dam outlet was saturated. We estimate that the accumulated water crossed the dam through an outlet likely located at the valley’s lowest elevation, i . e ., near 48.7 m ASL ( G1 in Figs 4B and Fig 6 ). In summary, the Gisr el-Mudir’s western wall likely acted as a first check dam to the Abusir wadi flows.
https://doi.org/10.1371/journal.pone.0306690.g006
The excavations performed on the eastern wall of the Gisr el-Mudir highlighted a lower structural quality [ 45 ]. Its shape is similar to that of the western wall, with a distinctive parabolic profile ( Fig 6 , line C-D ). Furthermore, it discloses two topographical singularities: first, its overall altitude is a few meters lower than the western wall ( Fig 7A ). Then, in the southern part of the eastern wall, a geophysics anomaly ( G2 in Figs 4B and Fig 6 ) was found to be a series of massive, roughly cut, ‘L’-shaped megaliths [ 45 , 66 ]. Before our study, these megaliths were thought to possibly be the remains of a monumental gateway–due to their similarities with the Djoser’s complex enclosure’s entrance–but their purpose was not specified [ 66 ]. According to our analysis, these megaliths could be the side elements of the water outlets, possibly slit openings [ 76 ] that were likely closed off by wood beams but could be opened to drain the basin. They are consistently found near a trench that is 2.2 m deep [ 45 ], which we believe is possibly the canal that guided outflowing water. In a nutshell, the eastern wall likely acted as a second check dam to the Abusir flows.
a. West-east elevation profile of the Gisr el-Mudir structure. b: Schematic reconstitution of the profile with water flow.
https://doi.org/10.1371/journal.pone.0306690.g007
In addition to the two dams formed by the western and eastern walls, the Gisr el-Mudir enclosure forms a basin ( Fig 4 ). It is closed to the north by another wall made of limestone blocks, though not very tall (likely <2m) because it is built on a natural ridge [ 45 ]. The basin’s southern boundary is also mostly made of a natural ridge. The possible absence of a masonry wall on certain portions on this side was unexplained by previous analyses [ 45 ]. However, it makes perfect sense when considering a reservoir function. Anchoring dams against side slopes is indeed the standard approach to guide flows and prevent outflanking [ 68 ].
In essence, the Gisr el-Mudir enclosure exhibits the defining features of a check dam ( Fig 7B ). The catchment it intercepts is large enough (15 km 2 ), plus eventual water derivation from the Wadi Taflah to produce flash floods transporting significant amounts of gravel, sand, mud, and debris due to its slope during intense rainfalls. The valley upstream of the western wall likely served as a first reservoir where the coarsest gravels tended to deposit. The overflowing water then filled the inner basin of the Gisr el-Mudir, where coarse sand would again deposit. Assuming a storage depth between 1 and 2 meters, the retention capacity of the basin would be approximately 220,000–440,000 m 3 . This volume is in line with the overall water volume of a flash flood that could be produced by the Abusir wadi, which is estimated to be about 75,000–225,000 m 3 , assuming 50 mm of rainfall and a 0.30 runoff coefficient. This key, first structure of the Saqqara hydraulic system would have then delivered clear water downstream in normal time, as well as muddy water with an eventually suspended load of fine sand and clay during rainfall events.
3.2.1 general configuration..
The Djoser’s Complex is surrounded by a vast excavation area, commonly referred to as the ’Dry Moat’ since Swelim spotted its outlines [ 77 , 78 ] ( Fig 3 , blue strip). The Dry Moat is alleged to be a continuous trench cut in the bedrock, up to 50 m wide and ≈3 km long, enclosing an area of ≈600 m by ≈750 m around the Djoser complex [ 77 , 79 , 80 ]. When considering an average depth of 20 m for the four sides of the trench [ 61 ], the total excavated volume is estimated at ≈3.5 Mm 3 , approximately ten times the Step Pyramid‘s volume. Due to the thick cover of sand and debris [ 61 ] accumulated over the past millennia, its precise geometry is incompletely characterized. The moat’s east and south channels are particularly debated [ 61 ].
According to Swelim, the moat’s south channel probably split into two parts, known as the Inner and Outer south channels [ 78 ] ( Fig 8 , blue strips). The Inner south channel is relatively shallow (5–7 m deep), 25–30 m wide, and spans approximately 350 m parallel to the southern wall of Djoser’s complex.
Water from the Abusir Lake can follow two parallel circuits.
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The ‘Deep Trench’ [ 81 ] ( Fig 8 , red rectangles and dotted lines) is built inside the Inner south channel, along its south wall. It is a ≈27 m-deep, 3 m-wide, and hundreds of meter-long rock-cut channel with several ‘compartments’. So far, only about 240 m [ 78 ] of its probable 410 m length have been subject to archaeological excavations in 1937–1938 [ 78 ], 1937–1945 [ 81 ], and 1975 [ 82 ]. Consequently, approximately 170 m remains unexplored, mainly due to the presence of the later Old Kingdom two groups of mastabas built above the trench and at risk of collapse if submitted to underground excavation (transparent grey parts in Fig 8 ).
Generally, two leading theories are highlighted in the literature to explain the purpose of the trench: (i) a quarry for the Djoser’s complex [ 47 , 83 ], or (ii) a spiritual function [ 78 , 84 , 85 ]. However, over recent years, authors have pointed out several specificities in the trench’s architectural layout, which seem irrelevant in a religious or mining context [ 1 , 86 , 87 ]. In particular, on the mining aspect, several authors estimate [ 45 , 86 ] that the form of the track suggests that the extraction of stones was not its sole or even primary function, as it does not match with the ancient Egyptian quarrying methods. Reader also considers that some parts of the trench which are ~27 m deep and covered with a rocky ceiling, are wholly unrealistic for quarrying operations and unlikely to have required the paving found near the trench’s bottom [ 45 ]. This point is further emphasized by the narrow width of the excavated Deep Trench (3m), which is impractical in a mining scenario.
On the spiritual aspect, Kuraszkiewicz suggests that the trench may have developed a ritual significance as a gathering place for the souls of the nobles to serve the dead King [ 86 ]. Monnier [ 1 ] considers that the discovery of several niches in the channel does not fully demonstrate the moat’s religious purpose and considers it secondary. The trench’s ritual significance is also regarded as secondary by Reader [ 45 ], who suggests the ritual aspects developed only after the complex’s construction and do not reflect the original function of the structure.
In 2020, based on the archaeological, geological, and climatic evidence, Wong was the first to introduce the idea that the trench may have had a completely different function, being filled with runoff water following downpours [ 37 ]. If so, this would explain why it was not until the reigns of Unas and Userkaf (V th Dynasty) that new graves occupied the moat. The onset of drier climatic conditions [ 31 , 88 ] around the end of the IV th Dynasty would have created more favorable conditions for new constructions inside the moat. Despite the potential impact of Wong’s assumption, it did not receive much attention in the literature. Nonetheless, the current authors believe that Wong’s conclusions make sense when considering Saqqara’s downstream localization of a watershed.
The Inner south channel and the Deep Trench are built inside the Unas Valley, a hydrological corridor connecting the Abusir wadi plain to the Nile floodplain ( Fig 3 ). Both were thus possibly submitted to (un)controlled flooding [ 34 , 61 ] from the Abusir wadi plain.
The Deep Trench connects at least three massive subterranean compartments [ 45 , 47 ] ( Fig 8 , red parts) meticulously carved out with precisely cut surfaces [ 78 ] ( Fig 9 ) and joined by a tunnel [ 77 ] . A fourth compartment, retroactively named compartment-0 ( Fig 10 ), likely exists [ 45 , 78 ]. On a large scale, the perfect geometric alignment of these compartments is remarkable, as well as their parallelism with the Djoser’s complex and their bottom level similar to those of the southern and northern shafts (≈27 m ASL). These spatial relationships have led some authors to consider that the trench was created as a part of Djoser’s Complex [ 86 , 89 , 90 ]. This assumption has been reinforced by Deslandes’ discoveries of at least two east-west pipes, about 80 m long, connecting the Djoser’s Complex’s subterranean layouts to the Dry Moat’s eastern side [ 91 ].
a: View from the west; b: View from the east. The workers in the background provide a sense of the structure’s immense scale and technicity.
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View of the south face.
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Taken together, the Deep Trench architecture highlights technical proficiency and suggests that the ancient Egyptians intended a technical function rather than a spiritual one. Surprisingly, despite the available clues, the Deep Trench has never undergone detailed engineering studies to analyze its features and identify its purpose. The following sections suggest a hydraulic rationale behind the trench’s internal layout (more details in the Supplement ).
Being largely described in the literature [ 77 , 86 , 92 ] , the compartments’ layouts are presented in detail in the Supplement . Considering its architecture and geographical location, the Dry Moat’s southern section combines the technical requirements of a water treatment system, including sedimentation, retention, and purification. Fig 10 illustrates a comprehensive outline of the installation’s functioning process. Similarly to the Gisr el-Mudir, we found that the Deep Trench compartments likely served to transfer water with low suspended sediment concentration to the downstream compartments by overflowing. The process of using a series of connected tanks to filter water and remove sediment is an ancient technique that has been extensively documented in archaeological and scientific literature [ 93 – 96 ]. This method has been employed for centuries to clean water and has played a significant role in the development of water treatment practices.
Compartment-0 presents the minimum requirements of a settling basin (considerable length and width, low entry slope, position at the entry of Unas hydrological corridor) whose purpose is to facilitate the coarse particles’ settling that would overflow from Gisr el-Mudir during heavy rainfalls. The descending ramp along the south wall identified by Swelim [ 97 ] may have permitted workers to dredge the basin and remove the accumulated sediments along the east wall ( Fig 10 ) . The very probable connection [ 45 , 97 ] between compartment-0 and compartment-1, blocked with rough masonry ( Fig 9B and S3 Fig in S2 File ), is consistent with an outlet overflowing structure. Additionally, when the flow rate in compartment-0 was too high, the tunnel or even the northern portion of the trench may have been used as a spillway bypass to evacuate excess water toward the eastern portion of the Unas wadi valley ( Fig 8 , safety circuit).
Compartment-1 is then consistent with a retention basin with > 3000 m 3 capacity ( Fig 10 , left part). The bottom stone paving with mortar joints probably limited water seepage through the bedrock. Its eastern end could go until the compartment-2 [ 45 ] to form a single compartment, but this point remains debated [ 78 , 97 ] .
Compartment-2’s is, unfortunately, largely unexplored ( Fig 10 ). Its downstream position might indicate a second retention basin or possibly an extension [ 45 ] of the first one. The western part of this compartment (stairs area) perfectly aligns with the base levels of the Djoser’s complex south and north shafts, which points towards a connection between the three [ 86 ] . If so, it would be aligned with the recently discovered pipe of a 200 m-long tunnel linking the bottom of Djoser’s Complex’s southern and northern shafts [ 91 ] (see next section, Fig 11 ). Compartment-2 would then be another, or an extended, retention basin equipped with a water outlet toward the north.
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Compartment-3 ( Fig 10 , right part) is likely a side purification basin for drinking water. Its position as an appendix of the primary water circuit connecting Gisr el-Mudir to Djoser’s complex seems optimal to minimize water circulation and maximize water-settling time, thus increasing its purification. The second and third sections likely allowed further settling of particles and would have served as reservoirs during dry periods. The relatively smooth walls of the whole structure would have hindered the growth of microbes, plants, and other contaminants, thereby helping maintain the water’s cleanliness [ 98 ] . Four surface wells allowed access to the end of the last compartment where the water, kept clear and fresh in the shadow of this subterranean monumental cistern, could be used by the building site workforce [ 99 ] .
The excavated volume of the Deep Trench is greater than 14,000 m 3 [ 77 , 86 , 92 ]. If we assume that most of the water available in the Wadi Taflah was diverted toward Saqqara, this volume could be filled about a dozen to more than one hundred times per year on average. We hypothesize a typical filling level of 45 m ASL in the Deep Trench, but an accurate topographical survey is lacking, and the maximum water level could vary between 40–52 m ASL, according to the surrounding terrain elevation.
In essence, we discovered and highlighted for the first time that the Deep Trench’s position and design are consistent with possible use as a water treatment and storage system capable of cleaning and storing thousands of cubic meters of water.
4.1 overview of the djoser’s complex’ substructure.
The internal and external architecture of the Djoser’s Complex is thoroughly documented [ 1 , 3 , 100 , 101 ]. The Supplement provides an overview of this structure. Basically, the six-step Step Pyramid itself stands slightly off-center in a rectangular enclosure toward the south and reaches a height of approximately 60 m ( Fig 11 ). The pyramid consists of more than 2.3 million limestone blocks, each weighing, on average [ 2 ], 300 kg, resulting in a total estimated weight of 0.69 million tons and a volume of ≈330,400 m 3 .
The substructure features at least 13 shafts, including two significantly sizeable twin shafts located at the north and south of the complex ( Fig 11 , insets 3&4), and an extensive and well-organized network of galleries descending up to 45 m below ground level [ 102 ]. The north shaft is surrounded by four comb-shaped structures distributed on each side and angled 90° apart. Ground Penetrating Radar (GPR) revealed that the twin shaft layouts are connected [ 91 , 102 ] by a 200 m-long tunnel. Moreover, at least two of the twelve shafts on the pyramid’s east side are connected to the supposed eastern section of the Dry Moat by two 80 m long pipes ( Fig 11 and Supplement ).
From our 3D models, we estimate that ancient architects extracted more than 30,000 tons of limestone from the bedrock to dig the whole underground structure. The total length of the tunnels and subterranean rooms combined is ~6.8 km. However, its layout and purpose remain primarily poorly known and debated [ 6 ].
The ‘north shaft’ is located under the pyramid of Djoser and is almost aligned with its summit. This shaft is ≈28 m deep and has a square shape with 7 m sides. Its bottom part widens to ≈10 m on the last, deepest 6 m, forming a chamber ( Fig 12 and S6 Fig in S2 File ). On its upper part, the shaft extends above the ground level by at least four meters inside the Step Pyramid in the shape of a hemispherical vault that was recently reinforced ( Fig 11 , inset 5 ). This upper part inside the pyramid body remains unexplored. However, as noticed by Lauer, the shaft sides above ground level display comparable masonry to that of the southern shaft, indicating a possible upward extension [ 3 ]. On the pyramid’s north side, a steep trench with stairs provides access to the shaft.
a.: Granite box of Djoser’s complex north shaft serving as an opening-closing system for the water flow coming from side tunnels -source: [ 113 ]. b.: Limestone piles supporting the box - source: [ 3 ]. c: Diagram of the North Shaft plug system. Redrawn from Lauer sketches [ 108 ].
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The ‘south shaft’ is located ~200 m south of the north shaft, close to the Deep Trench ( Fig 11 , inset 1 ). Its dimensions and internal layout are broadly similar to the north shaft’s. The substructure of the south shaft is entered through a west-facing tunnel-like corridor with a staircase that descends about 30 m before opening up inside the shaft. The staircase then continues east and leads to a network of galleries whose layout imitates the blue chambers below the Step Pyramid. As mentioned earlier, a 200 m-long tunnel connects the lower part of the north and south shafts ( Fig 11 , orange pipe). A series of deep niches located on the south face of the south shaft [ 97 ], the shape of which resembles that of the Deep Trench’s compartments 1 and 2, might indicate a former connection between both. This point remains to be confirmed by additional investigation.
The south shaft is connected to a rectangular shaft to the west via a tunnel-like corridor with a staircase that descends approximately 30 meters before opening up into the south shaft ( Fig 11 , inset 2 ). At the corridor level, a chamber has been cut into the bedrock parallel to the descending passage [ 3 ], towards the south. This chamber features several incompletely excavated niches on its south wall, which could extend under the south wall of the Djoser complex ( Fig 8 ). Pending further excavations, they might indicate a connection with the Deep Trench.
The initial purpose of the twin shafts’ granite boxes has been largely debated [ 15 , 100 ]. The presence of two shafts with two similar granite boxes and almost identical substructures was previously explained as a separation of the body and spirit of Djoser [ 100 ]. However, the Pharaoh’s body is actually missing and was not found during modern excavations. Several authors and explorers excluded the possibility of King Djoser’s burial in the north shaft [ 15 , 103 ]. Vyse claimed [ 15 ] that the box’s internal volume was too narrow for moving a coffin without breaking the body. Firth and Quibell considered [ 103 ] the fragments found by Gunn and Lauer [ 104 ] to be of mummies of ‘late date’, possibly belonging to the Middle or New Kingdom. Finally, a thorough radiocarbon dating [ 105 ] on almost all retrieved remains [ 104 , 106 , 107 ] located near the granite box excluded the possibility that ‘ even a single one of them ’[ 105 ] could have belonged to King Djoser. Therefore, although the northern shaft had clear funerary significance much later, its original purpose during the time of Djoser may have been different.
Unfortunately, the main part of the materials that filled the twin shafts was removed during past archaeological excavations, mainly in the 1930s [ 108 ], leaving only the two granite boxes at their bottom ( Fig 11 , insets 3 and 4 ). Therefore, the shafts’ internal layout description is mainly based on the explorers’ archaeological reports and testimonies[ 109 – 111 ].
The two granite boxes are broadly similar in shape and dimensions. Both are made of four layers of granite blocks and present top orifices closed by plugs that weigh several tons ( Fig 12A ). The southern box is slightly smaller, with a plug made of several pieces, making it less versatile. The north box does not lay directly on the underlying bedrock but is perched on several piles of limestone blocks supporting the lower granite beams ( Fig 12B ), tentatively attributed to robbers by Lauer [ 3 ]. The space around the box is connected with four tunnels arranged perpendicularly on each side of the shaft (see Supplement ). This space was filled with several successive layers [ 108 ] ( Fig 12C , grey parts). The lowermost layer consisted of coarse fragments of limestone waste and alabaster, making it permeable. Meanwhile, the upper layer, going up to the box ceiling’s level, was made of limestone jointed with clay mortar [ 108 ], i . e ., less permeable [ 112 ]. This ceiling was itself covered by a 1.50 m thick layer of alabaster and limestone fragments plus overlying filling ( Fig 12C , blue part), except around the plug hole, which was encircled by a diorite lining, a particularly solid rock ( Fig 12C , green part).
Directly above the granite boxes were ‘maneuvering chambers [ 108 ]’ that enabled the plug to be lifted. The plug closing the north shaft’s box has four vertical side grooves, 15 cm in diameter, intended for lifting ropes ( Fig 12C ) and a horizontal one, possibly for sealing. Below the chamber ceiling and just above the orifice, an unsheathed wooden beam was anchored in the east and west walls ( Fig 12C ). This beam likely supported ropes to lift the plug, similar to those found in the south shaft with friction traces [ 108 ].
Interestingly, the granite stones forming the granite box ceiling were bounded by mortar ( Fig 12A ), creating an impermeable barrier with the shaft’s lower part and leaving the plug’s hole as the only possible connection between the shaft and the inside of the box. Conversely, most joints between the box’s side and bottom stones, connected with the permeable bottom layer, were free from mortar.
These details, thoroughly documented during Lauer’s excavation [ 3 , 108 ] and visible on pictures ( Fig 12A and 12B ), clearly point to technical rather than symbolic application. Taken together, the granite box’s architecture and its removable plug surrounded by limestone clay-bound blocks present the technical signature of a water outlet mechanism.
When opened, such a plug system would have allowed the north shaft to be filled with water from the Deep Trench or, in another scenario, from the Dry Moat’s eastern section. The permeable surrounding filling would have permitted water discharge control from the four side tunnels. Then, the water could only seep through the granite box’s lower joints. This design would have prevented water from rushing through the system at high speed and with pressure shocks.
Considering water coming from the Deep Trench (elevation delta: 10–20 m), the retaining walls and the many layers’ cumulated weight stacked over the granite box acted as a lateral blockage and would have prevented the box ceiling from being lifted due to the underlying water pressure.
After gathering all the elements of this study, we deduce that the northern shaft’s layout is consistent with a hydraulic lift mechanism to transport materials and build the pyramid. Elements at our disposal indicate that the south and north shafts could be filled with water from the Dry Moat. A massive float inside the north shaft could then raise stones, allowing the pyramid’s construction from its center in a ‘volcano’ fashion ( Fig 13 ).
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Although a connection between the Compartment -2 and the Djoser shafts has yet to be identified, it is highly probable that sediment-free water from the Deep Trench was used in this system ( Fig 13 , disk ‘ 1 ’). This water quality would have reduced the risk of fouling and malfunction because it minimizes the presence of sand and clay that feed into the north shaft. This would prevent the deposition and progressive filling in the tunnels and connections, as well as the clogging of the joints between the bottom and side granite blocks of the box. The 200 m-long underground pipe [ 91 ] that connects the north and south shafts is then consistent with the transfer of water from the Deep Trench’s water treatment system to the north shaft, possibly via the south shaft.
Furthermore, there is a proven connection between the tunnels surrounding the north shaft and the Dry Moat through the Deslandes’ pipes [ 91 ] on the eastern side of the complex ( Figs 11 and 13 ). Pending further investigation, we hypothesize that the water inlet was located to the south ( Fig 13 , disk ‘ 1 ’), with the outlet(s) sending water toward the east through two juxtaposed pipes (disk ‘ 2 ’). Several horizontal galleries connected to these two pipes were acacia-cased [ 3 ], a technique commonly used to safeguard the walls in hydraulic works in ancient Egypt. A large stone portcullis [ 108 ] found in one of these galleries may have served as a versatile gate closed during the water filling of the north shaft.
In another scenario, the Deslandes’ juxtaposed pipes ( Fig 13 , disk ‘ 2 ’) could be considered as a water inlet for unfiltered water.
Finally, we hypothesize that a hydraulic lift, a massive float that was possibly made of wood and weighed several tons (see Supplement ), should run slowly inside the shaft to prevent instabilities and friction with the sides. The stones could have been elevated by filling and emptying cycles, allowing the lift to move up and down with stones ( Fig 13 ). These stones could have passed along the northern entrance until the central shaft. Recent discoveries have shown that this gallery was kept open until the very end of the pyramid’s construction, after which it was closed [ 1 , 91 ]. In our scenario, the stones could have been transported directly at ground level, corresponding to the pyramid’s first course, or slightly higher through a ramp penetrating in a (currently sealed) corridor some meters above the ground level. This configuration would have had the particular advantage of minimizing the elevation gain for which the hydraulic lift would be required. The stones could have been transported via the so-called ‘Saite gallery [ 114 ]’ in a final scenario. Although Firth [ 114 ] considers this gallery to postdate the III rd Dynasty, it remains possible that it was recut on the basis of an earlier gallery.
We developed a simple numerical model of the hydraulic lift to study its water consumption and loading capacity (see Supplement ). The model was kept as simple as possible to be easily checked and only intended to give relevant orders of magnitudes.
The hydraulic lift is modelled as a float loaded with stones to build the pyramid and with a vertical extension to raise this material at the necessary level. Based on the initial altitude of the lift, Z m , which cannot be below 17m from ground level (the bottom of the shaft was filled with the box and overlying rocks, see Fig 12C ), and assuming a loading of the material on the lift at the ground level, the maximum height that can be reached in one cycle is <17m. To achieve greater heights, we hypothesize that the lift platform was blocked during the float descent, e . g ., using beams (see Fig 14 ). This modification would have allowed the platform to reach higher altitudes by adding or unfolding an extension. For the top of the pyramid, the float could be conversely used as a counterweight when descending, pulling on ropes that would haul the platform after passing over pulleys above the shaft head. A dual-use method involving hauling during shaft draining and elevating during water filling would have been the optimal management approach.
The lift platform (red line), and extension support (orange line) during the unfolding of the lower element are represented. The associated holes are to be localized in further excavation of the upper part of the shaft.
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The beginning of the pyramid building was most probably performed using ramps prolonging the path from the local quarry, possibly the Dry Moat [ 44 ]. To provide an upper bound of water consumption, we modelled the pyramid building using the hydraulic lift from the first layer at ground level. Our model suggests that this upper bound value is 18 Mm 3 of water required to build the whole pyramid using the float to lift stones only when the shaft is filled (see Supplement ). A few million were required to build the first 20 m and could be saved if ramps were used instead. The total amount of water needed would have been reduced by about one-third if the float had been used as a counterweight, pulling on ropes to haul stones on a platform suspended in the top part of the shaft rather than being located on a wooden frame extension attached to the float. Finally, if both lifting (when filling the shaft) and hauling (when draining the shaft) were used, the water consumption would decrease by two-thirds. If the loading was not performed at ground level but rather through a ramp and gallery above ground level, about one-quarter of the water would be saved if, for instance, using a 5 m-high ramp and 43% for a 10 m-high ramp. Further investigation above the vault and on the pyramid sides could help to identify such an eventual gallery. If, conversely, the loading was performed about 13 m below ground level in the top part of the northern gallery ( S6 Fig in S2 File ), the water consumption would typically increase by two-thirds.
On the other hand, through our research and calculations, we have determined that the Wadi Taflah catchment had the capacity to supply 4–54 Mm 3 over 20–30 years of construction, therefore not enough when assuming only pessimistic values (lower bound for rainfall and runoff coefficient, fast construction and sub-optimal use of the lift just using it when water rose), but sufficient when assuming intermediate values, and eight-times enough water to meet this demand when assuming optimistic values (upper bounds of parameters and dual lifting-hauling functioning). If further research demonstrates that the higher clay and silt content possibly present at that time shortly after the Green Sahara period probably led to increased runoff coefficients by a factor of 2–3 or even more, the resource would be increased by the same factor.
The climatological conditions on the Saqqara plateau during the III rd Dynasty are still not well understood [ 37 ]. As a first assumption, we estimate that the water supply may have been continuous even without an upper Abusir lake’s permanent existence, thanks to the flow from the wadi Abusir and, more significantly, through a probable derivation system from the nearby Wadi Taflah, assuming this large catchment had a more perennial runoff regime. Pedological investigations would be worthwhile in the plateau area and in the talweg of both wadis to look for evidence of more frequent water flow.
As a result, the hydraulic mechanism may have only been usable when sufficient water supply was available, so it may have only been used periodically. Other techniques, such as ramps and levees, were likely used to bring the stones from the quarries and adjust their positions around the lifting mechanism or when it was not in operation.
A unified hydraulic system.
Based on a transdisciplinary analysis, this study provides for the first time an explanation of the function and building process of several colossal structures found at the Saqqara site. It is unique in that it aligns with the research results previously published in the scientific literature in several research areas: hydrology, geology, geotechnics, geophysics, and archaeology. In summary, the results show that the Gisr el-Mudir enclosure has the feature of a check dam intended to trap sediment and water, while the Deep Trench combines the technical requirements of a water treatment facility to remove sediments and turbidity. Together, these two structures form a unified hydraulic system that enhances water purity and regulates flow for practical uses and vital needs. Among the possible uses, our analysis shows that this sediment-free water could be used to build the pyramid by a hydraulic elevator system.
By its scale and level of engineering, this work is so significant that it seems beyond just building the Step Pyramid. The architects’ geographical choices reflect their foresight in meeting various civil needs, making the Saqqara site suitable for settling down and engaging in sedentary activities, such as agriculture, with access to water resources and shelter from extreme weather conditions. This included ensuring adequate water quality and quantity for both consumption and irrigation purposes and for transportation, navigation, or construction. Additionally, after its construction, the moat may have represented a major defensive asset, particularly if filled with water, ensuring the security of the Saqqara complex [ 115 ].
The hydraulic lift mechanism seems to be revolutionary for building stone structures and finds no parallel in our civilization. This technology showcases excellent energy management and efficient logistics, which may have provided significant construction opportunities while reducing the need for human labor. Furthermore, it raises the question of whether the other Old Kingdom pyramids, besides the Step Pyramid, were constructed using similar, potentially upgraded processes, a point deserving further investigation.
Overall, the hydraulic lift could have been a complementary construction technique to those in the literature for the Old Kingdom [ 8 , 10 ]. Indeed, it is unlikely that a single, exclusive building technique was used by the ancient architects but that a variety of methods were employed in order to adapt to the various constraints or unforeseen circumstances of a civil engineering site, such as a dry spell. Therefore, the beginning of the pyramid building was most probably performed using ramps prolonging the path from the local quarry. According to petrographic studies [ 47 ], the main limestone quarry of the Saqqara site could correspond to the Dry Moat that encircles the Djoser Complex, providing access on the four sides of the pyramid for the extracted blocks and reducing the average length of the ramps.
By their technical level and sheer scale, the Saqqara engineering projects are truly impressive. When considering the technical implications of constructing a dam, water treatment facility, and lift, it is clear that such work results from a long-standing technical tradition. Beyond the technical aspects, it reflects modernity through the interactions between various professions and expertise. Even though basic knowledge in the hydraulics field existed during the early Dynastic period, this work seems to exceed the technical accomplishments mentioned in the literature of that time, like the Foggaras or smaller dams. Moreover, the designs of these technologies, such as the Gisr el-Mudir check-dam, indicate that well-considered choices were made in anticipation of their construction. They suggest that the ancient architects had some empirical and theoretical understanding of the phenomena occurring within these structures.
The level of technological advancement displayed in Saqqara also raises questions about its place in history. When these structures were built remains the priority question to answer . Were all the observed technologies developed during the time of Djoser, or were they present even earlier? Without absolute dating of these works, it is essential to approach their attribution and construction period with caution. Because of the significant range of techniques used to build the Gisr el-Mudir, Reader estimates [ 70 ] that the enclosure may have been a long-term project developed and maintained over several subsequent reigns, a point also supported by the current authors. The water treatment facility follows a similar pattern, with the neatly cut stones being covered and filled with rougher later masonry. Finally, the Djoser Step Pyramid also presents a superposition of perfectly cut stones, sometimes arranged without joints with great precision and covered by other rougher and angular stones [ 3 ]. Some of these elements led some authors [ 6 , 100 ] to claim that Djoser’s pyramid had reused a pre-existing structure.
The Deep Trench was intentionally sealed off at some point in history, as evidenced by the pipe blockage between Compartment-0 and Compartment-1. The reasons are unknown and speculative, ranging from a desire to construct buildings (such as the Khenut, Nebet, or Kairer mastabas) above the trench to a technical malfunction or shutdown due to a water shortage. This sealing might also have been done for other cultural or religious purposes.
The current topography of the land around the Djoser complex, although uncertain given the natural or anthropogenic changes that have occurred over the last five millennia, does not support the existence of a trench to the east side. Therefore, our observations join those of Welc et al. [ 61 ] and some of the first explorers [ 63 ], reasonably attributing only three sections to the Dry Moat.
This article discloses several discoveries related to the construction of the Djoser complex, never reported before:
North Saqqara map showing the relation between the Abusir water course and the Step Pyramid construction process (Inset). The arrows figuring the flow directions are approximate and given for illustrative purposes based on the Franco-Egyptian SFS/IGN survey [ 52 ]. Satellite image: Airbus Pléiades, 2021-07-02, reprinted from Airbus D&S SAS library under a CC BY license, with permission from Michael Chemouny, original copyright 2021.
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Here are the steps to write the background of the study in a research paper: Identify the research problem: Start by identifying the research problem that your study aims to address. This can be a particular issue, a gap in the literature, or a need for further investigation. Conduct a literature review: Conduct a thorough literature review to ...
The background of the study is a section in a research paper that provides context, circumstances, and history leading to the research problem or topic being explored. It presents existing knowledge on the topic and outlines the reasons that spurred the current research, helping readers understand the research's foundation and its significance ...
The background of the study is the first section of a research paper and gives context surrounding the research topic. The background explains to the reader where your research journey started, why you got interested in the topic, and how you developed the research question that you will later specify. That means that you first establish the ...
Fitterling, Lori. Researching and Writing an Effective Background Section of a Research Paper. Kansas City University of Medicine & Biosciences; Creating a Research Paper: How to Write the Background to a Study. DurousseauElectricalInstitute.com; Background Information: Definition of Background Information. Literary Devices Definition and Examples of Literary Terms.
The background of a study in a research paper helps to establish the research problem or gap in knowledge that the study aims to address, sets the stage for the research question and objectives, and highlights the significance of the research. The background of a study also includes a review of relevant literature, which helps researchers ...
While writing your background, you must: Mention the main developments in your research area. Highlight significant questions that need to be addressed. Discuss the relevant aspects of your study. Related reading: 4 Step approach to writing the Introduction section of a research paper. The secret to writing the introduction and methods section ...
The background of a study is the first section of the paper and establishes the context underlying the research. It contains the rationale, the key problem statement, and a brief overview of research questions that are addressed in the rest of the paper. The background forms the crux of the study because it introduces an unaware audience to the ...
Table of contents. Step 1: Introduce your topic. Step 2: Describe the background. Step 3: Establish your research problem. Step 4: Specify your objective (s) Step 5: Map out your paper. Research paper introduction examples. Frequently asked questions about the research paper introduction.
Usually, the background forms the first section of a research article/thesis and justifies the need for conducting the study and summarizes what the study aims to achieve. How to structure the background . In this section, the author usually outlines the historical developments in the literature that led to the current topic of research concisely.
A good background section. Describes current state of knowledge. Explains rationale for question (how & why) Sets up design choices. Backs these up with current references.
The introduction section of a research paper provides background information about the research problem, the research question, and the research objectives. ... Researchers often write research papers to publish their findings in academic journals or to present their work at academic conferences. Publishing research papers is an important way ...
A good Background section explains the history and nature of your research question in relation to existing literature - a "state of the art.". This section, along with the rationale, helps readers understand why you chose to study this problem and why your study is worthwhile. This article will show you how to do this.
How to Write a Research Paper. SPORTSCIENCE, Perspectives/Research Resources. Department of Physiology and School of Physical Education, University of Otago, 1999; Green, L. H. How to Write the Background/Introduction Section. Physics 499 Powerpoint slides. University of Illinois; Woodall, W. Gill. Writing the Background and Significance Section.
The structure of a background study in a research paper generally follows a logical sequence to provide context, justification, and an understanding of the research problem. It includes an introduction, general background, literature review, rationale, objectives, scope and limitations, significance of the study and the research hypothesis.
Background information example. To write the background of a research paper, you must understand the overall structure and know exactly how this section should look. Let's see an excellent example of a background section for a research paper on the topic of "The Impact of Social Media on Mental Health":
Research background is a brief outline of the most important studies that have been conducted so far presented in a chronological order. Research background part in introduction chapter can be also headed 'Background of the Study." Research background should also include a brief discussion of major theories and models related to the research problem. Specifically, when writing research ...
Answer: The background of the study provides context to the information that you are discussing in your paper. Thus, the background of the study generates the reader's interest in your research question and helps them understand why your study is important. For instance, in case of your study, the background can include a discussion on how ...
Many research documents when reviewed wholesomely in most instances fails the background study test as the authors either presume it is a section notes on the research or just a section to ensure ...
Bem, Daryl J. Writing the Empirical Journal Article. Psychology Writing Center. University of Washington; Denscombe, Martyn. The Good Research Guide: For Small-Scale Social Research Projects. 5th edition.Buckingham, UK: Open University Press, 2014; Lunenburg, Frederick C. Writing a Successful Thesis or Dissertation: Tips and Strategies for Students in the Social and Behavioral Sciences.
The dissertation background/history should illustrate your concepts, questions, and theory. Your background section should relate to your research topic in question; this requires you to make explicit links between the stories you tell and the questions and theoretical approaches you are using. To do this, try to ensure a tight fit between this ...
The rationale of the study is the justification for taking on a given study. It explains the reason the study was conducted or should be conducted. This means the study rationale should explain to the reader or examiner why the study is/was necessary. It is also sometimes called the "purpose" or "justification" of a study.
how to write background of the study in research paper l y step by step guideThe background section should discuss your findings in chronological order to hi...
The background forms a part of the introduction section of the paper. It has to set the context of the study, by introducing the research problem, talking about what existing studies say about the problem, what gaps you have found, and why you wish to address these gaps. So, the background forms a key and prominent part of the introduction.
Papers usually end with a concluding section, often called the "Discussion." The Discussion is your opportunity to evaluate and interpret the results of your study or paper, draw inferences and conclusions from it, and communicate its contributions to science and/or society. Use the present tense when writing the Discussion section. •
White Paper: A white paper is an informational document, issued by a company or not-for-profit organization, to promote or highlight the features of a solution, product, or service. White papers ...
The in-text citation appears within the body of the paper (or in a table, figure, footnote, or appendix) and briefly identifies the cited work by its author and date of publication. This enables readers to locate the corresponding entry in the alphabetical reference list at the end of the paper.
In this post, I discuss situations where students and researchers use ChatGPT to create text and to facilitate their research, not to write the full text of their paper or manuscript. ... ChatGPT or other AI tools in your research, describe how you used the tool in your Method section or in a comparable section of your paper. For literature ...
The Step Pyramid of Djoser in Saqqara, Egypt, is considered the oldest of the seven monumental pyramids built about 4,500 years ago. From transdisciplinary analysis, it was discovered that a hydraulic lift may have been used to build the pyramid. Based on our mapping of the nearby watersheds, we show that one of the unexplained massive Saqqara structures, the Gisr el-Mudir enclosure, has the ...