*"Socio-hydrology is still dominated by hydrologists, who have adopted a perceived hegemonic attitude toward inter-disciplinary collaboration".*

The socio-hydrology community is dominated by hydrologists. If the socio-hydrology's objective is to break the existing boundaries through a systems approach that leads to a holistic understanding of complex human-water systems, hydrologists must be open to actively learning from and working with other disciplines and do not need to pull every exciting concept toward their own domain. Rephrasing the concepts from other fields might not the most constructive step toward scientific interdisciplinarity.

The socio-hydrology literature has shown a strong tendency to borrow fashionable phrases and exciting concepts from other fields (e.g., co-evolution, tipping points, self-organization, Anthropocene, black swan, ludic fallacy, unintended consequences). Using "popular terms and fashionable phraseology" socio-hydrology [2] and the fame of the socio-hydrology proposers have made the socio-hydrology papers highly cited and popular. Invention of socio-hydrology has also sparked the idea of developing socio-hydrogeology, socio-climatology, socio-meteorology. Yet, the popularity of socio-hydrology has mainly emerged in networks that are less familiar with the water resources systems and CHANS literature. Socio-hydrology remains to be dominated by hydrologists who are less "traditional" than the mainstream hydrologists but more "traditional" than the water experts who have been working in the human-water systems space for decades. We noted many papers in the literature that use socio-hydrology as a keyword or in their title but do not make a proper connection to socio-hydrology "concepts" or literature throughout their articles. Seidl and Barthel [5] also noted that 26% of the socio-hydrology papers they reviewed mention the term socio-hydrology in their title, abstracts, and keywords but "do not refer to the concept of socio-hydrology presented by Sivapalan et al. [1]". Seidl and Barthel expressed their "surprise", claiming that when they contacted the authors of several of those papers, they confirmed that they were not aware of the socio-hydrology concepts.

While the desire for adopting fashionable concepts from other disciplines is high among the socio-hydrologists, the inappropriate use of such concepts significantly hurt the scientific rigor of some socio-hydrology publications. The interest of the original proposers of socio-hydrology [1] in predicting black swan events (also questioned by Koutsoyiannis [2] in his review report), reflects their misunderstanding of the black swan theory [41] which asserts that black swans might be predictable retrospectively, not prospectively. As another example, Di Baldassarre et al. [104] explained the known mechanism of increase in water demand as the result of increasing water supply (e.g., [24,35,38,69]) as the Jevons' paradox (rebound effect). However, Jevons' paradox in economics is about the increased efficiency in use of a resource (an intervention on the demand side), not an intervention on the supply side. In other words, the total resource volume remains constant and the rebound is caused due to increase in the rate of resource consumption. But, in the featured examples of Di Baldassarre et al. [104], changes in the supply side, i.e., increasing the volume of resource (through building a new reservoir) had led to an increase in demand (by enabling "agricultural, industrial or urban expansion") that ended up offsetting the increase in supply. In their examples, the intervention is on the supply side (reservoirs) as opposed to the Jevons' paradox which involves an intervention on the demand side (e.g., increasing resource use efficiency through technology advancements). While the governing structure of the two problems and the overall behavior in the variables of interest (e.g., supply-demand gap) might be the same, the interventions that cause this behavior can be different. That is why using generic

coupled human-water systems archetypes for this type of problems has been proposed [20,51,56]. The "fixes that fail" archetype (Figure 4) can explain the behaviors of both problems (Jevons' paradox and viscous supply-demand cycles) as discussed earlier (see Section 2.2).

Borrowing concepts and terms from other disciplines can be illuminating and valuable as long as they are used correctly and are not rephrased unnecessarily. Relabeling and rewording the syntaxes and terminologies of other fields might create short-term popularity. Though, in the long run, it can increase our distance from scholars in other fields rather than breaking the boundaries and barriers to facilitate interdisciplinary and trans-disciplinary interactions. We already have too many terminologies in different disciplines that are worded differently but mean the same thing.

#### **3. E**ffi**ciency of Our Peer-Review Systems**

We raised some concerns about the claims that have been made by socio-hydrology literature. These concerns are about the general interest area of socio-hydrology and not specific to certain publications. Some of these concerns are not new but have remained unaddressed since the day the "new science" was proposed in 2012 [1]. The socio-hydrology community could have avoided most of these concerns through essential scientific efforts on a proactive basis (e.g., by a comprehensive review of the existing literature). However, these basic concerns could have also been addressed reactively and in response to peer review comments. If we attribute the systematic overlooking of the water resources systems, system dynamics, and CHANS research in the socio-hydrology publications to the unfamiliarity of socio-hydrologists with the existing literature, then we must be seriously concerned about the major flaws and deficiencies of our peer review system. Evidently, the peer review system has systematically failed in providing constructive feedback to our colleagues in socio-hydrology.

As discussed in Section 1, the questions asked in this paper are not supposed to undermine socio-hydrology. We consider the increasing interest in socio-hydrology as a positive development, whilst remaining surprised that these issues have not been raised in the peer review of 180 socio-hydrology publications by some of the best water resources journals that are supposed to have a fundamental role in setting the science agenda and recognizing the value of novel insights [190]. This calls for revisiting our peer review system and asking how an effective review system can be set up when a "new science" is proposed. Who is qualified to review papers that belong to a "new" space? How must we set up a reliable review system that promotes innovation and interdisciplinarity but does not compromise our scientific research procedures and standards?

Another issue that has contributed to the existing deficiencies in the socio-hydrology literature is our culture in academia. We do not want to challenge, shame, and disrespect our colleagues. So, we have strong reservations about putting our thoughts, comments, and feedback in writing in fear of offending our colleagues. When our colleagues are more senior and famous, our concerns grow further. The two of us also had serious reservations about writing this article. However, this culture must change. We have to be more helpful to each other and not be afraid of providing constructive feedback to our colleagues if we care about them and really believe in the power of science and interdisciplinary approaches. The concerns we listed here are not new and we have heard our colleagues talking about them for years but did not share them formally. When our formal peer review systems fail, we have a stronger responsibility to protect the integrity of science and help our colleagues flourish and succeed.

While the flaws of our peer review system require great attention, we should not forget that as academics, we still have an ethical responsibility to ensure that to the best of our knowledge what we propose as a "new" contribution does not already exist. It is very hard to imagine that the socio-hydrology community has remained unaware of the ongoing and past research in other areas such as system dynamics with a strong overlap with their work, especially when they refer to their early products as system dynamics models, use CLDs, and frequently use the popular terms such as unintended consequences, complexity, feedbacks, evolution, etc.

#### **4. Conclusions and Final Remarks**

Undoubtedly, the seminal paper of Sivapalan et al. [1] and their subsequent leadership has created an increasing interest in social systems in the hydrologic science community. The socio-hydrologists' success is evidenced by the number of published socio-hydrology papers since 2012, as well as the number of researchers who identify themselves as socio-hydrologists or use the socio-hydrology term in their publications. Yet, socio-hydrology seems to have become mostly popular among the mainstream hydrologists with limited familiarity with the past work in the human-water systems space, not to those who have worked in this space for decades. The socio-hydrologists' interest in holistic understanding of human-water systems, which necessitates systems approaches, together with their desire to advise policy creates a natural overlap between socio-hydrology and research in water resources systems, SES and CHANS areas. Nevertheless, socio-hydrologists insist that their work is different from the works of other groups without providing sufficient scientific evidence.

Socio-hydrology was originally proposed as a "new science" but so far it has not been more than an interest area or a sub-field of hydrology. While the socio-hydrology literature shows a great tendency to borrow fashionable syntaxes and popular concepts from the literature of other fields, socio-hydrologists have systematically overlooked the past and ongoing work in the coupled human-water systems space and this has led to reproduction of some existing concepts under new names.

Some concerns about the practicality of socio-hydrology goals, the types of unique tools/methods it uses, the new questions it asks, and its boundaries and points of departure from existing domains have been around and remained unaddressed since 2012. Thus, it is not clear to us why socio-hydrology insists on creating arbitrary boundaries with water resources systems and CHANS. The overviewed deficiencies in the socio-hydrology literature reflect the existing shortfalls of our peer review system that require serious attention, especially in the era of increasing interest in developing new interdisciplinary fields in response to our research needs.

Generally, the ex-ante creation of a new science or even a new field is not scientific and sets the counterproductive precedent of creating new sciences based on personal judgement rather than scientific proof. Establishing a new field must be done through a scientific procedure that recognizes the new needs, carefully examines what is available, identifies the gap, proposes meaningful and new questions, and suggests solid evidence for the possibility of answering such questions using new, old, or revised approaches and methods. Certainly, this procedure was not followed by socio-hydrology and as a result, after eight years, we still have a hard time figuring out what socio-hydrology means and what it is trying to do that is novel. This can be attributed to our ignorance, but we believe that this confusion has been contagious and common for a lot of non-socio-hydrologists.

In our opinion, the valuable contribution of the socio-hydrologists is not their "new science", models, ambitious statements, and exciting agenda, but their perseverance and dedication to reminding the mainstream hydrologists about the need for taking the human factor into account. For the reasons discussed in the paper, a good number of socio-hydrology papers would have been nearly unpublishable in their current forms in traditional water resources management or water resources systems journals. The same is true if these papers had been reviewed by those familiar with the larger water resources systems, system dynamics, and CHANS literature. Nevertheless, the appearance of these papers in the most reputable hydrology/water resources journals and the dedicated efforts of the socio-hydrology leaders to promote their "new science" at major gatherings of the field have resulted in: (1) an increasing recognition of the need for incorporating the human element into traditional hydrologic models; (2) an increasing interest, especially among the early-career researchers to study and model coupled human-water systems; and (3) a big surge in the production of coupled human-water systems literature (mainly based on systems dynamics methods) that provide potentially useful insights for policymaking. Thanks to the efforts of the socio-hydrology leaders, the coupled human-water systems community now has a bigger and more enthusiastic task force. This success must be celebrated and promoted as it can strengthen the current efforts of those who have been working on coupled human-water systems for a long time.

Meanwhile, to avoid wasting economic resources and human talents, the socio-hydrology leaders have a great responsibility to ensure that their community is aware of and recognizes the major contributions of the water resources systems and CHANS communities to studying coupled human-water systems. The presented boundaries and coordinates of the socio-hydrology "science" seem to be suffering from a misunderstanding of what other communities (e.g., water resources systems) are doing. Socio-hydrologists have an ethical responsibility to review what other groups have done and clearly indicate their point of departure, if such departure is necessary at all.

Hjorth and Madani [191] warned that within the water resources profession, our mental frames [192], beliefs, expectations, and judgements could converge over time as we continue to read the same journals and go to the same conferences. Repetitions make our frames stronger and empower them in our brains. To conserve our mental frames, we have a tendency to preoccupy ourselves with issues that are closer to our comfort zones. We disregard the observations that do not fit into our frames as we know well that "a frame modification would imply adjustment, insecurity, and even confusion, possibly not just for the individual but for an entire community" [191]. This issue could be among the reasons that the socio-hydrology, water resources systems, and CHANS communities have not successfully interacted with each other in a complementary fashion. Instead, each group has remained defensive of its own framing of problems and its own unique solutions to it. As proponents of the systems approach in decision making in the real world, we have failed to adopt such an approach in our own world, i.e., academia, where most of the real-world complexities do not exist and the stakes are supposedly much lower. Instead, as academics with strong interest overlaps, we have competed to create and lead our own territories, dismissing what others have done. It is true and very unfortunate that "we work hard, but separately, to solve interlinked problems" [191].

New challenges require changed priorities and new thinking. We need to update our common sense and come to grips with our mistaken beliefs [115]. Common sense can unite us but creating new science might divide us. Thus, if we want a unified effort, we must function within a common-sense framework [191] instead of developing and protecting our own science. The lack of common understanding makes scientists compete to interpret problems [115], propose new terms, "correct" evaluation methods [193] and disciplinary jargons [194], and prescribe solutions based on their own preferences and knowledge of their own domain instead of focusing on problem solving. If the subject is more important, more people will try to compete and pull it toward their domain where they feel most empowered by their own capabilities and perspectives [195]. Creating a common sense for hydrologists that humans must be an integral element of water models can unite the water resources community. However, insisting on creating a "new science" of socio-hydrology while undermining the existing work in the human-water systems space might be a frustrating precedent that can lead to further fragmentation of the already siloed scientists.

Lastly, despite the possible misinterpretations of our intention, we decided to write this paper as outsiders who remain interested but confused about the developments and contributions of socio-hydrology. The ability to give constructive and critical feedback, without causing resentment, is a superpower that we might not possess. Nevertheless, we remain hopeful that these comments encourage our colleagues in socio-hydrology to sharpen their messages, more comprehensively consider the existing literature, and, if appropriate, join their forces and merge their work with other scholars who are working on human-nature and human-water systems problems as unity can certainly make us more powerful.

**Author Contributions:** K.M. and M.S.-J. did the analysis and literature review through extensive discussions. M.S.-J. did the literature search in the WoS database and produced the figures. K.M. wrote the manuscript with input from M.S.-J. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Acknowledgments:** We thank the Guest Editor, Slobodan Simonovic, for the invitation to write this paper. We are also thankful to the anonymous reviewers for their constructive feedback.

**Conflicts of Interest:** The authors declare no conflict of interest.
