VIC-AMBHAS input files for the Philippine Hydrological Model

The Philippine Hydrological Model is the first national-scale hydrological model of the Philippines (Scheidegger et al 2023, 2024, 2025). Its primary purpose is to quantify components of the hydrological cycle at the national level, with spatio-temporal patterns of precipitation, evapotranspiration, runoff and groundwater recharge as model outputs. We have developed an integrated surface water-groundwater model based on the Variable Infiltration Capacity (VIC) macro-scale hydrological model (Liang et al. 1994, Hamman et al 2018), into which we have added a one-layer, 2D lateral groundwater flow model (Scheidegger et al. 2021). Groundwater recharge is derived from the interaction of the groundwater model with the VIC soil by allowing bi-directional exchange of water between the aquifer and the soil. The model is run at a 2 km grid resolution and is parameterised with, and driven by, globally available datasets describing the land surface, including soil and vegetation properties. The model outputs include: evapotranspiration, runoff, groundwater recharge, baseflow, groundwater levels, and soil moisture. The resulting modelling framework provides a means to develop understanding of the water resources across the Philippines and aims to support future national water resources planning. Development of the Philippine Hydrological model began under the ‘Philippines Groundwater Outlook (PhiGO)’ project - a collaboration between the British Geological Survey (BGS), Ateneo de Manila University (ADMU), and the Philippine’s National Water Resources Board (NRWB). The project was joint-funded under the NERC-Newton and DOST-PCIEERD programme, understanding the impacts of hydrometeorological hazards in Southeast Asia (project NE/S003118/1). Under PhiGO, models of Panay and Pampanga were developed. Using subsequent funding from BGS’s International Geoscience Research and Development (IGRD) programme the model was then expanded to cover the whole of the Philippines. The latest developments have been undertaken under the Philippine Hydro Hub, a collaboration between the University of the Philippines Diliman, Ateneo de Manila University and the British Geological Survey. This work has been funded by the UK Department for Science Innovation and Technology's International Science Partnerships Fund in partnership with the British Council. To run this model the VIC-AMBHAS-GRID version of the code is used, accessed here: https://github.com/BritishGeologicalSurvey/VIC/blob/VIC-AMBHAS-GRID/vic/extensions/AMBHAS/readme.md More info can be found here: https://philippinehydrohub.org/news-events/blogs/what-next-for-a-hydrological-model-of-the-philippines.html https://mapapps.bgs.ac.uk/philippines-national-hydrological-model/?_ga=2.111079430.2018701401.1774525884-1014372910.1774525884 References: Hamman, J J, Nijssen, B, Bohn, T J, Gergel, D R and Mao, Y X 2018. The Variable Infiltration Capacity model version 5 (VIC-5): infrastructure improvements for new applications and reproducibility. Geoscientific Model Development 11(8), 3481-3496, https://doi.org/10.5194/gmd-11-3481-2018. Scheidegger, Johanna. 2025 Future projections of the hydrology of the Philippines : dataset summary. Nottingham, UK, British Geological Survey, 28pp. (OR/25/010) (Unpublished) Scheidegger, Johanna. 2024 User guide : BGS Philippine National Hydrological Model dataset. British Geological Survey, 45pp. (OR/24/023) Scheidegger, Johanna; Barkwith, Andrew; Jackson, Christopher; Mansour, Majdi; Guzman, Aileen. 2023 Philippine National Hydrological Model. British Geological Survey, 12pp. (OR/23/053) (Unpublished) Scheidegger, Johanna M.; Jackson, Christopher R.; Muddu, Sekhar; Tomer, Sat Kumar; Filgueira, Rosa. 2021 Integration of 2D Lateral Groundwater Flow into the Variable Infiltration Capacity (VIC) Model and Effects on Simulated Fluxes for Different Grid Resolutions and Aquifer Diffusivities. Water, 13 (5), 663. 10.3390/w13050663