Multidirectional Shifts in Hydrological Connectivity Result From Hydraulic Barriers

Abstract The weakening of hydrological connectivity caused by hydraulic barriers and its impact on the ecological environment has gained worldwide attention. Previous studies have primarily focused on the obstructive effect of barriers, often overlooking its influence on the internal connectivity of regulated water systems. The study employed a new conceptual framework of hydrological connectivity and utilized the connectivity assessment tool to assess the impact of the proposed Poyang Lake Hydraulic Project (PLHP) on the lake's internal connectivity. The estimated impacts were based on various factors, including the connectivity function (CF), the spatial distribution of the connected object (CONNOB), as well as duration and timing of connection. Key findings indicate that the PLHP will enhance the total connectivity and general connectivity involving inundation depth of the lake. This enhancement will result in increased CF values, expanded CONNOBs and prolonged connection durations. Conversely, the PLHP will weaken the general connectivity involving flow velocity and effective connectivity. As a result, CF values will decrease, CONNOBs will shrink, and connection durations will be shorter. It is important to note that the impact of hydraulic barriers varies depending on evaluation metrics, duration, timing, direction, distance, location, hydrological year, and regulation stage. Therefore, it is not appropriate to simply categorize the barrier impact as “weakening” or “enhancing.” This study innovates the knowledge of hydraulic barriers from the perspective of internal connectivity and is expected to provide more comprehensive theoretical guidance for water resource regulation and eco‐environmental protection.