SIMULATION OF GROUNDWATER FLOW REGIME: A CASE OF YALA RIVER CATCHMENT, KENYA
DOI:
https://doi.org/10.33736/jcest.10765.2026Keywords:
Aquifer, groundwater, hydrogeology, recharge, visual-MODFLOWAbstract
The hydrogeological regime that includes the vadose and phreatic zones significantly supports the hydrological cycle and influences surface and groundwater bodies for a sustainable ecosystem. Since these zones are unseen, they are prone to anthropogenic threats, which include groundwater overabstraction, reduced infiltration or aquifer recharge, and adversity from climate change. There is also inadequate knowledge of groundwater capacity and flow regime in catchments. This study developed hydrogeological knowledge to understand the groundwater flow regime and provide a decision tool for catchment management. The model was developed using Visual MODFLOW and ran through a set of scenarios to widely understand hydrogeological aspects in the Yala River catchment. While running the model through day 147 to 190, the trends indicated a maximum head of 0.00624 m and a minimum of -0.00676 m. The head changes recorded a maximum of 0.00524 m and a minimum of -0.0068 m with the residual of less than 2, indicating that the verifications were within acceptable levels. It was observed that the catchment storage improved from 0.050238 m3/day in the reference scenario to 7.16 m3/day, and when the catchment was assumed to be well managed, the model’s groundwater inflow-outflow difference increased to 429 m3/day, an increase of 422.4 m3/day in the zonal unit, which gave a 98.33% increase. There was evidence of groundwater backflow at the midblock, indicating the development of a cone of depression that requires further research. It is worth noting that the boundary conditions used in the calibrated model were representative combinations of selected parameter values and boundary conditions. This model can be replicated for simulation of the hydrogeological flow regime in other catchments with similar or relative geographical characteristics.
References
Nyakundi, R. M., Makokha, M., Mwangi, J. K., & Obiero, C. (2015). Impact of rainfall variability on groundwater levels in Ruiru municipality, Kenya. African Journal of Science, Technology, Innovation and Development, 7(5), 329–335. https://doi.org/10.1080/20421338.2015.1085157
Kuria, Z. N. (2018). Groundwater Resources Assessment of Lamu Island along Coastal Kenya.
Okune, P. (2019). Threats to the survival of river Yala in Kenya. GRIN Verlag. Retrieved from https://www.perlego.com/book/4830852/threats-to-the-survival-of-river-yala-in-kenya
Mogaka, H., Gichere, S., Davis, R., & Hirji, R. (2009). Climate variability and water resources degradation in Kenya- improving water resources development and management. World Bank.
Kiluva, V. M., Mutua, F. M., Makhanu, S. K., Ong, B. T. I., & Mwikali, K. V. (2011). Rainfall runoff modeling in Yala River basin of Western Kenya. Journal of Meteorology and related sciences, 10(5), 1–11. Retrieved from http://hdl.handle.net/1834/7242
Okungu, J., Adeyemo, J., & Otieno, F. (2017). Scenario Analysis of Water Supply and Demand Using WEAP Model: A Case of Yala Catchment, Kenya. American Journal of Water Resources, 5(4), 125–131. Retrieved from http://pubs.sciepub.com/ajwr/5/4/5
Kanda, E. K., Avulala, M. K., Olendo, E., Mukolwe, M. M., Awandu, W., Lutta, V. O., Ong’or (T), B., & Khaemba, A. W. (2023). Assessment of groundwater quality in Vihiga County, Kenya. Progress in Sustainable Development: Sustainable Engineering Practices, 1, 249–264. https://doi.org/10.1016/B978-0-323-99207-7.00010-5
Anderson, M. P., Woessner, W. W., & Hunt, R. J. (2015). Simulation of Flow and Advective Transport (second.). ed. U. S. Geological Survey, Wisconsin Water Science Center, Cross Plains, Wisconsin: Applied Groundwater Modeling. https://doi.org/10.1016/C2009-0-21563-7
Waswa, G. W., & Lorentz, S. A. (2019). Dynamics of groundwater flow and upwelling pressure heads at a wetland zone in a headwater catchment. SN Applied Sciences, 1(9), 1052–1059. https://doi.org/10.1007/s42452-019-1052-9
Fitts, C. R. (2012). Groundwater Science. Groundwater Science. Science Ltd: Elsevier. https://doi.org/10.1016/C2009-0-62950-0
Bradford, R. B., & Acreman, M. C. (2003). Applying MODFLOW to wet grassland in-field habitats: A case study from the Pevensey Levels, UK. Hydrology and Earth System Sciences, 7(1), 43–55. https://doi.org/10.5194/hess-7-43-2003
Fatapour, E., Afrous, A., Aminnejad, B., Saremi, A., & Khosrojerdi, A. (2026). Mapping Flood Zone in Khorram Abad River by Integrating Hydrological and Hydraulic Models. International Journal of Engineering, Transactions B: Applications, 39(5), 1122–1138. https://doi.org/10.5829/ije.2025.39.05b.07
Kumar, P., Thakur, P. K., Bansod, B. K. S., & Debnath, S. K. (2016). Assessment of the effectiveness of DRASTIC in predicting the vulnerability of groundwater to contamination: a case study from Fatehgarh Sahib district in Punjab, India. Environmental Earth Sciences, 75(10). https://doi.org/10.1007/s12665-016-5712-4
Naji, L., Tawfiq, M., & Jabber, A. K. (2016). Global Journal of Engineering Science and Researches Mathematical Modeling of Groundwater Flow. C) Global Journal Of Engineering Science And Researches, 3(10), 2348–8034. https://doi.org/10.5281/zenodo.160914
Dung, N. V., Merz, B., Bárdossy, A., Thang, T. D., & Apel, H. (2011). Multi-objective automatic calibration of hydrodynamic models utilizing inundation maps and gauge data. Hydrology and Earth System Sciences, 15(4), 1339–1354. https://doi.org/10.5194/hess-15-1339-2011
Babu, R. G. (2015). Sensitivity Analysis of Modflow Used For the Simulation of Ground Watertable Fluctuations. International Journal of Agriculture Sciences, 7(13), 828–833. Retrieved from www.india.gov.in
Pradeep Kumar, G. N., & Anil Kumar, P. (2014). Development of Groundwater Flow Model Using Visual MODFLOW. International Journal of Advanced Research, 2(6), 649–656. Retrieved from http://www.journalijar.com
Downloads
Published
How to Cite
Issue
Section
License
Copyright (c) 2026 UNIMAS Publisher
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
Upon acceptance of an article, the corresponding author on behalf of all authors will be asked to complete and upload the Copyright Transfer Form (refer to Copyright Issues for more information on this) alongside the electronic proof file.
Copyright Transfer Statement for Journal
1) In signing this statement, the author(s) grant UNIMAS Publisher an exclusive license to publish their original research papers. The author(s) also grant UNIMAS Publisher permission to reproduce, recreate, translate, extract or summarize, and to distribute and display in any forms, formats, and media. The author(s) can reuse their papers in their future printed work without first requiring permission from UNIMAS Publisher, provided that the author(s) acknowledge and refer the publication in the Journal.
2) For open-access articles, the author(s) agree that their articles published under UNIMAS Publisher are distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License (CC BY-NC-SA 4.0) which permits unrestricted use, distribution, and reproduction in any medium, for non-commercial purposes, provided the original work of the author(s) is properly cited.
3) For subscription articles, the author(s) agree that UNIMAS Publisher holds the copyright or an exclusive license to publish. Readers or users may view, download, print, and copy the content, for academic purposes, subject to the following conditions of use: (a) any reuse of materials is subjected to permission from UNIMAS Publisher; (b) archived materials may only be used for academic research; (c) archived materials may not be used for commercial purposes, which include but not limited to monetary compensation by means of sale, resale, license, transfer of copyright, loan, etc.; and (d) archived materials may not be re-published in any part, either in print or online.
4) The author(s) are responsible to ensure their submitted work is original and does not infringe any existing copyright, trademark, patent, statutory right, or propriety right of others. The corresponding author has obtained permission from all co-authors prior to submission to the journal. Upon submission of the manuscript, the author(s) agree that no similar work has been or will be submitted or published elsewhere in any language. If the submitted manuscript includes materials from others, the authors have obtained permission from the copyright owners.
5) In signing this statement, the author(s) declare that the researches which they have conducted comply with the current laws of the respective country and UNIMAS Journal Publication Ethics Policy. Any experimentation or research involving humans or the use of animal samples must obtain approval from the Human or Animal Ethics Committee in their respective institutions. The author(s) agree and understand that UNIMAS Publisher is not responsible for any compensational claims or failure caused by the author(s) in fulfilling the above-mentioned requirements. The author(s) must accept the responsibility for releasing their materials upon request by Chief Editor or UNIMAS Publisher.
6) The author(s) should have participated sufficiently in the work and ensured the appropriateness of the content of the article. The author(s) should also agree that they have no commercial attachments (e.g. patent or license arrangement, equity interest, consultancies, etc.) that might pose any conflict of interest with the submitted manuscript. The author(s) also agree to make any relevant materials and data available upon request by the editor(s) or UNIMAS Publisher.
