**5. Conclusions**

Unrestricted urban expansion, burgeoning population and industrialization among various other anthropogenic factors have put significant stress on water resources all over the world [1]. In this context, the Morobe Development Foundation (MDF), a not-for-profit community-based organization located in Lae, Morobe Province, Papua New Guinea has undertaken research to understand the symbiotic relationship that exists between water systems of the Bumbu basin and the health and welfare of the resident communities. This study seeks to facilitate a capacity to link the quality of surface waters to multiple social, economic and environmental factors di fferentially and geographically distributed by tracing the travel history of surface waters through varying landscapes. These include urban, semi-urban, dense forests, green space and regenerating forests. For this purpose, we developed an analytical protocol to determine the potential impact the above-mentioned factors can have on surface water quality. This is essential for our future work, and a positive contribution to the study of water quality in general. It is worthwhile to mention that the protocol can be applied to many factors in addition to those mentioned in this research, based on its underlying point, line or raster-based characteristics. Although previous studies [4–11,18,20] consider a variety of factors, the uniqueness of the protocol is in its examination of the relationship between quality of water, physicochemical characteristics, WASH practices [17,19] and socio-economic parameters. The protocol will help us to understand the relationship that exists between the above parameters and the inhabitants of the Bumbu Watershed, a study that is the first of its kind for the region. Consequently, this will provide relevant insights to aid our upcoming projects which are aimed at addressing probable risks to human health created by poor water quality in the Bumbu basin [14].

We utilized a diversity of spatial analytical tools and techniques to responsibly analyze an array of environmental and anthropogenic data inputs possessing the potential to impact water quality. The study confirms the value of the conceptual framework put forward by Granger et al. [3] to identify potential sources of impact, their mobilization and their delivery to water systems. For our future studies, the practical value of the protocol will be tested in its ability to (a) interpret, interpolate and estimate appropriate values of diverse inputs of other factors associated with water quality as measured at WQI sampling stations; (b) provide the tools to estimate the spatial distribution of variables reported in household surveys; and (c) appropriately estimate the importance values of those survey parameters at the WQI sample sites. The protocol and its procedures described in this paper were generalized enough to be applicable in other geographical settings to determine the influence of runo ff of a variety of factors, and to calculate the relative importance and correlation of these factors with other SEE parameters. Through this study, we intend to bring the protocol and its applications into the limelight, gather international attention of researchers and volunteers and simultaneously garner local support for our future work.

**Author Contributions:** Conceptualization, W.D. and L.W.; methodology, L.W.; software, L.W.; validation, L.W., W.D.; formal analysis, L.W.; investigation, W.D., L.W. and S.B.; resources, L.W. and W.D.; writing—original draft preparation, L.W., W.D. and S.B.; writing—review and editing, L.W., W.D., S.B., M.M. and W.S.W.M.J.; visualization, L.W. and S.B.; funding acquisition, M.M. and W.S.W.M.J.; supervision, W.D.; project administration, W.D. All authors have read and agreed to the published version of the manuscript.

**Funding:** The publication costs related to the research have been covered by the National University of Malaysia (UKM) research gran<sup>t</sup> GUP-2018-132.

**Acknowledgments:** The research was supported and implemented with pro bono contributions by volunteers from the United Nations Online Volunteering Program. The authors would like to acknowledge Esmaeel Adrah (UN volunteer from Syria), John Kennedy Boafo (Geomatic Engineer from Ghana) and Roshan Padel (Lecturer, Acme Engineering College, Purbanchal University, Nepal) for providing GIS-related insights relevant to our research. The authors also thank Kamal Wahp (UN Volunteer from UAE) and Suwarna Shukla (Doctoral Scholar at Indian Institute of Management, Indore, India) for their suggestions and valuable edits related to the previous versions of this manuscript. The authors would also like to thank the three anonymous reviewers who helped to improve the quality of the manuscript. The authors also express their appreciation to Nancy Yang of the MDPI Remote Sensing team and to the members of the Institute of Climate Change, UKM, Malaysia.

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



**Table A1.** GPS survey of the 8 water sampling sites of UA series.



