TITLE:
Considerations for the Hydraulic Design of Gravity-Fed Water Conduits in Areas with Rugged Terrain
AUTHORS:
Rodrigo Ruíz-Santos, Humberto Silva-Hidalgo, María Socorro Espino-Valdés, Adán Pinales-Munguía, Cornelio Álvarez-Herrera, Álvarez Jorge-Lucero
KEYWORDS:
Water Availability, Water Sources, Accessibility to Water Resources, Topographic Conditions
JOURNAL NAME:
Open Journal of Fluid Dynamics,
Vol.16 No.1,
March
23,
2026
ABSTRACT: The design of gravity-fed hydraulic systems in mountainous terrain profiles still has challenges, especially in rural areas. The steep topography can induce air in pipes, leading to a change of flow regime, hydraulic area reduction, and hydraulic head losses. Furthermore, the transition between pressurized and free-surface flow, which frequently occurs in pipelines with steep slopes, that is, in which this article focuses, can significantly reduce the hydraulic head and drastically decrease the flow capacity. This experimental work demonstrated that the actual conveyance capacity in a physical model was reduced by up to 75% compared to the theoretical value. Failure to consider this problem in the design of conveyance systems in steep terrain can lead to the incorrect application of mathematical models and conventional hydraulic design software, which do not account for flow regime transitions such as single-phase pressurized flow (liquid), two-phase pressurized flow (liquid and gas), or free-surface flow (liquid at atmospheric pressure). This analysis documents a problem that can be common in conveyance systems in rugged terrain, especially low-flow systems serving small mountain communities. It also highlights the urgent need to integrate advanced and specific criteria into the design of gravity functioning conveyance systems to ensure a safe and efficient water supply.