Reservoir Region Research Articles

The Effect of the Reservoir Regulation Ability on the Water Consumption Rate During the Hydro–Wind–Photovoltaic Integration

The combined operation of hydropower and renewable energy impacts the hydropower operation efficiency, which exhibits different effects while the reservoir is deployed various regulation abilities. This study attempts to investigate the effect of reservoir regulation storage on the average daily water consumption rate. A case study of the integration of hydro–wind–photovoltaic located in Western China shows the differences mentioned above and explains the mechanism of the effect on the daily water consumption rate. It was concluded that (1) with increasing penetrations of renewable energy (from 0 to 90%), the daily water consumption rate mostly displays a trend of descent and then ascent; (2) with the increasing regulation ability of the reservoir (from 0.8 to 5.35 × 108 m3), the water consumption rate increases in the dry season but decreases in the flood season; (3) the hydropower output and net water head are two factors that cause the water consumption rate to rise and fall; and (4) a balance point between the net water head rise and the output reduction is pointed out. The findings of this study provide technique support for the research of water utilization efficiency during the renewable energy mix.

Revealing joint evolutions and causal interactions in complex ecohydrological systems by a network-based framework

Abstract. There is evidence that climate change and human activities are changing ecohydrological systems, yet the complex relationships among ecological (normalized difference vegetation index, gross primary productivity, and water use efficiency) and hydrological variables (runoff, soil water storage, groundwater storage, etc.) remain understudied. This study develops a novel framework based on network analysis alongside satellite data and in situ observations to delineate the joint evolutions (phenomena) and causal interactions (mechanisms) in complex systems. The former employs correlations, and the latter uses physically constrained causality analysis to construct network relationships. This framework is applied to the Yellow River basin, a region undergoing profound ecohydrological changes. Results suggest that joint evolutions are controlled by compound drivers and direct causality. Different types of network relationships are found – namely, joint evolution with weak causality, joint evolution with high causality, and asynchronous evolution with high causality. The upstream alpine subregions, for example, where the ecological subsystem is more influenced by temperature, while the hydrological one is more driven by precipitation, show relatively high synchronization but with weak and lagged causality between two subsystems. On the other hand, ecohydrological causality can be masked by intensive human activities (revegetation, water withdrawals, and reservoir regulation), leading to distinct evolution trends. Other mechanisms can also be deduced. Reductions in water use efficiency in the growing season are directly caused by the control of evapotranspiration, and the strength of control decreases with the greening land surface in some subregions. Overall, the proposed framework provides useful insight into the complex interactions within the ecohydrological systems for the Yellow River basin and has applicability to broader geographical contexts.

Precisely Designed Hydrophilic Networks in Microporous Layer for High Performance of Proton Exchange Membrane Fuel Cells.

Proton exchange membrane fuel cell (PEMFC) is considered the next promising generation of power devices for vehicles. The microporous layer (MPL) improves the performance through effective water management. In this study, local hydrophilic networks of nano- and macropores are formed in different MPLs. The measured internal contact angle to water confirms that Vulcan carbon black (VB) is helpful for the formation of hydrophilic pores. The MPL sample containing 10% VB (P1-H) exhibits the best performance under a wide range of humidities. Its peak power density reaches 1.51 W/cm2 under 60% relative humidity (RH) and drops only 1.99% under 80%RH. As shown in the three-dimensional simulation model, the hydrophilic nanopores preferentially serve as water reservoir regions to ensure a certain amount of water for membrane hydration and control the water droplet size at the interface. The ohmic resistance and mass transfer resistance of P1-H are reduced under a high current density. The MPL containing hydrophilic macropores (P3-H) displays a slight performance improvement. Despite enhanced air permeability, hydrophilic macropores directly drain water and result in membrane dehydration. The findings provide an optimized strategy for the precise design of MPL to achieve high performance and adaptation under a wide range of humidity.

Redistribution of dissolved inorganic nitrogen loading and transport in global rivers via surface water regulation.

Surface water (SW) regulation, including reservoir regulation and surface water use, alters the soil-river hydrological processes and then influences the dissolved inorganic nitrogen (DIN) transport from rivers to oceans. However, global response of the DIN transfer to such human activity has not been well investigated. Therefore, in this study, we have taken advantage of a recently-developed land surface model to show the effects of SW regulation on DIN loading and transport in global major rivers. Three simulations were conducted at the global scale over the period of 1991-2000. Results show that, acceleration on riverine N loading caused by the SW regulation was more noticeable. With the reservoir regulation only, removal rates of DIN in most rivers were reduced by 5%, up to 20%, while the increase of removal rate in some reaches occurred when the DIN was transferred back to soil through SW withdrawal and use. Influenced by the SW regulation, DIN flow has decreased obviously by 100-1000tNyr-1. Mean DIN flow was most significantly reduced in the Yellow River basin. Yangtze River, Mississippi River, and Nelson River suffered from the strong effect of such water regulation. The DIN exported to oceans was reduced as well. Mean reduction of 40-50% occurred for those exported to the Pacific Ocean, the Atlantic Ocean and the Indian Ocean, while slight effect for the estuaries into the Arctic Ocean. The impact on the DIN exported to the Atlantic Ocean was lasting decreasing from 50% to 40%, while the trend of the impact on that exported to the Pacific Ocean was opposite. There was no evident temporal change in the impacts on the DIN transferred to the Arctic Ocean and the Indian Ocean. The findings of this study could provide new insights for the researches on nitrogen change in rivers under the impacts of human water use.

Multi-index evaluation of drought conditions in Northeastern Algeria using remote sensing tool

Drought is a complex natural disaster with profound impacts on environmental, social, and economic systems globally. This research investigates drought conditions in the Koudiet Mdaouar Basin, located in northeastern Algeria, through a comprehensive analysis of satellite-derived indicators from 2019 to 2023. Employing advanced remote sensing and GIS-based methodological approaches, the study systematically evaluates vegetation health, thermal stress patterns, and water resource dynamics, with particular focus on the Koudiet Mdaouar reservoir region. The analysis reveals a significant progressive decline in ecological conditions, characterized by deteriorating vegetation cover, intensified thermal stress, and severe water scarcity. These findings not only highlight the region's environmental vulnerability but also demonstrate the intricate interplay between climatic changes and local ecosystem dynamics. The research emphasizes the necessity of developing adaptive water resource policies and underscores the potential of integrated satellite and ground-based observation techniques for more precise local drought assessments, offering critical insights for environmental management and climate resilience strategies.

Risk assessment of potential rock collapse in Fenghuang Mountain, three gorges reservoir area, China

On 8 October 2017, persistent heavy rainfall triggered a rock collapse on Fenghuang Mountain in Wuxi Town, located within the Three Gorges Reservoir region of China. Subsequent field investigations and monitoring identified several potentially unstable rock masses in the area, posing a significant threat to the safety of nearby residents and their property. In this study,the Rapid Mass Movement Simulation (RAMMS) numerical tool was used to perform a back analysis of the rock collapse event. The well calibrated numerical model was then used to assess the risk of the potential unstable rock masses in the study area. The rock collapse on Fenghuang Mountain descended rapidly along the slope, with the dislodged material accumulating at the base and obstructing the road at the foot of the slope. Some debris breached the embankment and entered the Daning River. The computed maximum velocity during the rock collapse event was approximately 9.14 m/s, with an average maximum deposit thickness of around 4.48 m. The back-analysis of the rock collapse event closely aligns with the observed failure process and deposit morphology documented through field investigation. Using the well calibrated numerical model, a dynamic analysis was conducted on the potential unstable rock mass. The risk assessment indicates that the potential unstable rock mass is prone to instability, with a high likelihood of a subsequent rockfall under extreme rainfall conditions. The computed average maximum velocity for the potential rockfall is 33.83 m/s, with an average maximum deposit thickness of 2.20 m. The computed maximum impact pressure is about 164 kPa, which would result in significant damage to the road below. Additionally, a maximum wave height of 1.38 m from the surge caused by potential rockfall entering the Daning River was calculated by a semi-empirical model. This research offers a novel approach and methodology for assessing the risk of such hazardous events in similar geological setting globally.

Seismic hazard assessment in the Shamkir-Mingachevir reservoir region through ground response analysis

Seismic hazard assessment in the Shamkir-Mingachevir reservoir region through ground response analysis

Landslide-oriented disaster resilience evaluation in mountainous cities: A case study in Chongqing, China

Natural and human-made disasters are threatening cities around the world. The resilience of cities plays a critical role in disaster risk response and post-disaster recovery. In mountainous cities, landslides are among the most frequent and destructive hazards. This study presents a novel methodological framework for assessing the spatial resilience of mountainous cities specifically against landslides. Focusing on Chongqing in the Three Gorges Reservoir region, this study conceptually divides the disaster resilience of mountain cities to landslides into two dimensions: environmental resilience and social resilience. This study developed a comprehensive database by compiling data from 4,464 historical landslide events, incorporating 17 environmental resilience indicators and 16 social resilience indicators. Random forest (RF) model was employed to evaluate environmental resilience, achieving a high AUC of 0.968 and an accuracy of 97.1 %. Social resilience was assessed by the Analytic Hierarchy Process (AHP), and comprehensive resilience was ranked by the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS). Key findings include: (1) Establishing a multi-dimensional resilience indicator system that effectively assesses landslide-oriented resilience in mountainous cities. (2) Comprehensive resilience in mountainous cities exhibit distinct spatial clustering patterns. Regions with lower environmental resilience are mainly characterized by high rainfall and complex terrain. higher social resilience concentrated in city centers, while peripheral regions face challenges due to weaker economies and inadequate healthcare infrastructure. (3) In the future development of mountain cities, comprehensive and sustainable strategies should be adopted to balance the relationship between environmental resilience and social resilience. This study provides a robust framework for disaster prevention and resilience assessment in mountainous cities, which can be applied to evaluate the disaster resistance capabilities of other mountainous cities.

Reservoir Regulation Changed Terrestrial Particulate Organic Carbon Transport and Burial Processes off the Yellow River Mouth

AbstractThe dynamic behavior of particulate organic carbon (POC) is crucial for understanding biogeochemical carbon cycling in coastal and oceanic environments. However, intense watershed human activities have significantly altered the POC transport and burial in the estuary‐coast continuum. Here, we developed a novel parameterization scheme that incorporates grain‐size constraints to investigate the dispersal and accumulation processes of POC off the Yellow River mouth during the water‐sediment regulation scheme (WSRS) using a three‐dimensional hydrodynamic model (FVCOM). The result shows that the model successfully captures the offshore transport and hydrodynamic sorting of POC, which leads to a progressive increase in POC content with offshore dispersion and significant variations in POC and sediment deposition across different isobaths. Rapid fluctuations in river discharge and sediment composition during WSRS stages result in noticeable differences in sedimentation patterns for sediment and POC. At the Water‐regulation stage, distinct differences are observed in the distribution of riverine POC and sediment across various isobaths. In contrast, during the Sediment‐regulation stage, these differences are significantly reduced due to the finer riverine sediment. Compared to the sediment‐regulation, the Water‐regulation plays a crucial role in enhancing the effective burial of POC. Coarse‐grained sediment can form an armored layer that protects OC from disturbance. Additionally, increased runoff during this stage promotes the offshore transport of POC to a less energetic environment (>10 m in depth). This study provides valuable insights into POC dynamics in high‐turbidity estuarine and coastal environments. It underscores the importance of employing comprehensive modeling approaches to elucidate these complex processes.

Design flood estimation of cascade reservoirs based on vine-copula flood regional composition

Study regionThe study region is the Yalong River basin, the largest tributary of the Jinsha River in China. Study focusThe most likely flood regional composition (MLFRC) method has been widely used to estimate the design flood of cascade reservoirs in the operation period, in which the Gumbel copula or t-copula is often selected to fit the theoretical joint distribution. However, the Gumbel copula is only suitable for 2 or 3 cascade reservoirs, while the t-copula has great uncertainty in parameter estimation. In this study, we introduce vine-copula into MLFRC framework to estimate design flood of cascade reservoirs, and comprehensively compare the universality of different copulas through statistical experiments and a case study on the cascade reservoirs in Yalong River basin. New hydrological insights for the regionThe results indicated that: (1) Vine-copula significantly outperforms Gumbel copula and t-copula in terms of fitting the theoretical joint distribution. (2) The vine-copula based MLFRC method can successfully solve the different flood regional composition schemes most accurately in the simulated scenarios. (3) Compared with the design floods in construction period, the design floods in operation period in the Yalong River basin decrease significantly due to the regulation of upstream reservoirs. The 1000-year design flood at basin outlet section decrease by about 40 %.

Integrating best management practices with dynamic water environmental capacity for optimal watershed management

Definite setting of water quality target is a challenge when considering non-point source (NPS) pollution which demands reasonable allocation of reduction requirements. However, research on the dynamic water environmental capacity (WEC) allocation aimed at reflecting varying rainfall conditions has rarely been performed. In this study, the relationship between rainfall and WEC was explored by a stochastic algorithm, while then reduction target was allocated in a small catchment, the Three Gorges Reservoir Region (TGRR), China. Combined with the distributed model, three commonly adopted best management practices (BMPs) were located precisely. The results indicate that a specific rainfall threshold exists for water quality (84 mm/month for the study area) which reveals the comprehensive effect of rainfall flushing and dilution effect. At 90% confidence, the total phosphorus (TP) load was 1518 kg/yr, and the ideal WEC was 1194 kg/yr, with excess of 324 kg/yr. In addition, the highest amount of inflow phosphorus can be reduced by fertilizer reduction (FR) with 303.8 kg/yr. Besides, slope-to-terrace (ST) measures should be implemented mainly in the upper reaches, while FR should be preferentially considered in the lower reaches. For the small watershed dominated by agricultural NPS, this study can provide accurate water quality target settled by WEC calculation impacted by uneven rainfall and a feasible watershed management.

Single-Shot Time-Lapse Target-Oriented Velocity Inversion Using Machine Learning

In this study, we used machine learning (ML) to estimate time-lapse velocity variations in a reservoir region using seismic data. To accomplish this task, we needed an adequate training set that could map seismic data to velocity perturbation. We generated a synthetic seismic database by simulating reservoirs of varying velocities using a 2D velocity model typical of the Brazilian pre-salt ocean bottom node (OBN) acquisition, located in the Santos basin, Brazil. The largest velocity change in the injector well was around 3% of the empirical velocity model, which mimicked a realistic scenario. The acquisition geometry was formed by the geometry of 1 shot and 49 receivers. For each synthetic reservoir, the corresponding seismic data were obtained by estimating a one-shot forward-wave propagation using acoustic approximation. We studied the reservoir illumination to optimize the input data of the ML inversion. We split the set of synthetic reservoirs into two subsets: training (80%) and testing (20%) sets. We point out that the ML inversion was restricted to the reservoir zone, which means that it was inversion-oriented to a target. We obtained a good similarity between true and ML-inverted reservoir anomalies. The similarity diminished for a situation with non-repeatability noise.

Morphological, Epizotological, and Molecular-Genetic Description of the Species Schyzocotyle acheilognathi (Yamaguti, 1934), a Parasite of the Digestive System of Fishes of Khorezm Region's Reservoirs, Uzbekistan

Morphological, Epizotological, and Molecular-Genetic Description of the Species Schyzocotyle acheilognathi (Yamaguti, 1934), a Parasite of the Digestive System of Fishes of Khorezm Region's Reservoirs, Uzbekistan

Ecological effects of land use and land cover change in the typical ecological functional zones of Egypt

Evaluation the value of ecosystem services can provide crucial reference for formulating ecological protection plans and making informed management decision. This study utilized Landsat remote sensing images as the data source and employed land-use transfer chains and land use transfer matrix methods to compare the ecological effects of land use and land cover change(LUCC) in the two typical ecological functional zones of Egypt, one area isthe northern region of Egypt with the Priority function of Economic Development, another area is the Nasser Reservoir area with the priority function of water conservation. The key findings are as follows: (1)The northern region of Egypt and the Nasser Reservoir exhibited different trends across the ecological functional zones.From 1985 to 2020, the northern region of Egypt is characterized by an increase in arable land and impervious surface,the Nasser Reservoir area is distinguished by the expansion of water and a reduction in sand.(2) Key land transfer patterns vary significantly between the ecological functional zones of the northern region of Egypt and the Nasser Reservoir. From 1985 to 2020, the Egypt’s northern region experienced significant shifts between arable land, sand, and impervious surfaces. The conversion of arable land to impervious surfaces represented 2.41% of the total arable land transfer area, while sand converted to impervious surfaces accounted for 11.68% of the total sand transfer area. In the Nasser Reservoir region, significant conversions occurred between water, grasslands, and sand. Sand converted to water made up 3.83% of the total sand transfer area, while grassland converted to water compriseed 5.38% of the total grassland transfer area. (3) The ecological benefits of the northern region of Egypt and the Nasser Reservoir have increased significantly. In northern region of Egypt, the primary drivers of this increase in ecological service value are the conversion of arable land and grasslands, along with the ecological development and utilization of sand. In the Nasser Reservoir area,the inflow of water and the continued outflow of sands are the main factors contributing to the rise in ecosystem service value. (4) Differentiated LUCC management should be implemented for different ecological functional zones. In northern region of Egypt, the focus should be on balancing ecological security with human development, while the Nasser Reservoir area should prioritize water resource protection and sustainable development. The research findings are not only significant for optimizing LUCC but also for enhancing ecosystem service functions in Egypt.

Resolving spatially complex interactions between hydrodynamics and biogeochemical processing in a large reservoir with metalimnetic oxygen deficits

Deoxygenation in the deep water of stratified lakes and reservoirs due to climate warming and human activities poses a threat to crucial limnetic ecosystem services. Metalimnetic oxygen minima (MOM) typically occurs during the mid to late stages of limnetic stratification. To investigate the mechanism of MOM during stably stratified periods in the Panjiakou Reservoir, northern China, four years of in-situ monitoring was conducted in parallel with longitudinal-vertical 2D modeling. The model simulated the hydrodynamic, water quality, algal, and DO processes in 2017 and 2020, and was calibrated and verified by the measurements. Three scenarios were designed to test the impact of hydrological processes and the high oxygen-consuming sedimentation zones (HOCSZ). We concluded that the stratification and the corresponding advection generated in the metalimnion are the driving forces of MOM in the reservoir, and the limnetic eutrophication-related benthic HOCSZ are the seedbeds of the metalimnetic hypoxia. This unique spatial setting driving the biogeochemical processing and MOM dynamics required a new generation of modelling, incorporating spatial inhomogeneities of sediment characteristics and a sophisticated resolution of hydrodynamics. Metalimnetic horizontal advection, hypolimnetic upwelling currents, sedimentation hot spots and the formation of high oxygen consumption zones became the major initiation processes leading to MOM. The numerical modeling not only represented the occurrence, development, and extinction of MOM but also comprehensively explained the spatial differences in the vertical morphology of MOM and its inter-annual variations. Our studies help to identify management strategies to mitigate the impacts of MOM on aquatic ecological security and drinking water quality, thus supporting the optimization of reservoir regulations.

Nutritional status of the reservoir tributary backwater area and implications for nutrient control

Understanding the spatial and temporal distribution and driving factors of the nutritional status in the backwater area of typical tributaries in the Three Gorges Reservoir Region (TGRR) is important for the prevention and control measures. In this study, the Environmental Fluid Dynamics Code (EFDC) was used to extend in situ monitoring data, followed by the application of hydrogen and oxygen isotope data and scoring methods to predict the nutritional status in the backwater area of the Daning River. The results indicated that the nutritional status-sensitive period mainly ranged from May-October and was distributed at the end of the backwater area and tributary bay. The water temperature and intermediate density flow were identified as the key factors inducing deterioration in the nutritional status at the end of the backwater area and tributary bay, respectively. Nutrient reduction in the mainstream and tributary areas significantly affected the nutritional status in the backwater area. Notably, hydrodynamic adjustment under reservoir objectives is indispensable for improving the water environment in tributary bay after reaching the water quality standard. Our findings highlight the necessity of focusing on the upper reaches of the tributaries and reservoir for nutrient control and emphasize the importance of combining reservoir operation strategies to mitigate the deterioration in the nutritional status.

The coupling characteristics and influencing factors of the "homestead-cultivated land system" in the Three Gorges Reservoir Region of China: A farmer perspective

Homesteads and cultivated land are crucial elements of the rural territorial system. Their coupling characteristics and changing patterns are essential for understanding the evolution of rural human-land systems and for developing coordinated rural development strategies. This study takes Huilong Village and Pingba Village in the TGRR, employing methods such as GIS spatial analysis, comprehensive index evaluation, coupling coordination degree model, and geographic detector model. The analysis focuses on the coupling characteristics and influencing factors of the “HCS” in these villages and proposes optimization strategies to provide scientific guidance for village planning, selection of high-quality rural development paths, and strategy design. The main findings are as follows: (1) The spatial distribution of homesteads and cultivated land in typical villages exhibits clear traffic directionality. The spatial coupling of the “HCS” demonstrates significant convergent evolution and adjacent distribution characteristics. (2) The utilization coupling of the “HCS” in Huilong Village and Pingba Village is predominantly high, with 98.72% and 94.62% of farmers, respectively, being highly coupled. However, the degree of coupling coordination is mostly barely coordinated. (3) The primary factors influencing the coordinated development of the “HCS” in the study area include the utilization conditions of homestead and cultivated land, labor status, and economic status. These factors can be categorized into four types: labor factor restrictions, nonagricultural development disturbance, agricultural development, and lagging farming conditions. Differentiated development strategies are proposed for each type. This research enhances the understanding of the coupling between homestead land and cultivated land, offering valuable insights for regional village planning, high-quality development path selection, and government decision-making.

Identification and Deformation Characteristics of Active Landslides at Large Hydropower Stations at the Early Impoundment Stage: A Case Study of the Lianghekou Reservoir Area in Sichuan Province, Southwest China

Reservoir impoundment imposes a significant triggering effect on bank landslides. Studying the early identification of landslides and their stability concerning reservoir water levels and rainfall is vital for guaranteeing the safety of residents and infrastructure in reservoir regions. This study proposed a method for establishing a dynamic inventory of active landslides at large hydropower stations using integrated remote sensing techniques, demonstrated at Lianghekou Reservoir. We employed interferometric stacking synthetic aperture radar (stacking-InSAR) technology, small baseline subset interferometric synthetic aperture radar (SBAS-InSAR) technology, and optical satellite images to identify and catalogue active landslides. Moreover, we conducted field investigations to examine the deformation characteristics of landslides. Finally, Pearson’s correlation analysis was employed to evaluate the response between deformation values, reservoir water levels, and rainfall. The results revealed 75 active landslides, including 12 long-term active landslides before impoundment and 63 new landslides after impoundment, which were primarily concentrated in the Waduo and Yazho–Zatou regions. The correlation coefficient between landslide deformation values and the reservoir level was high (0.93), while the correlation coefficient with rainfall was low (0.57). The results of this research offer a crucial foundation for preventing and mitigating landslides in reservoir areas.

Earthquake migration characteristics and triggering mechanisms in the Baihetan Reservoir Area based on machine-learning microseismic detection

SUMMARY The Baihetan Reservoir, the second largest in the world, is located at the intersection of multiple large active fault zones on the eastern boundary of the Sichuan-Yunnan rhombic block. After impoundment on 6 April 2021, many earthquakes occurred around the reservoir area submerged by water. The largest ML 4.7 earthquake in the reservoir area occurred after the water level reached its highest point. But the seismogenic structures and mechanisms of earthquakes in the reservoir area are still unclear. Based on dense array data from the reservoir area, this paper uses the experimental site submodel of USTC-Pickers, transfer learned with ‘DiTing’ data set of China to obtain a high-precision earthquake catalogue that is twice as large as that the manual catalogue. This study show that earthquakes in the reservoir region primarily occur on secondary faults of pre-existing ones, characterized by a prominent feature of high dip angles trending northwest to southeast. Combined with the spatiotemperal migration characteristics of earthquakes and the relationship between earthquakes and water levels, we infer that most earthquakes are rapid response type and may be induced by rapid increase in elastic stress. Only the spatiotemporal distribution image of the ML 3.2 earthquakes sequence in the dam site-Toudaogou section conforms to the law of pore pressure diffusion, and belongs to the fast response type, which may be induced by the poroelasiticity coupling mechanism. The ML 3.0 earthquake swarm with deep depths in the Heishui River section belongs to the delayed response type and may be induced by the poroelasiticity coupling mechanism.

Estimation of phosphorus input on county-based scale is more appropriate to formulate phosphorus management policies

The excessive phosphorus input generated by human activities has broken the nutritional balance of ecosystem. This study focused on the Three Gorges Reservoir Region, where human activities are concentrated. It involved the innovative selection of county subunits to provide a clearer analysis of different components contributing to net anthropogenic phosphorus input (NAPI) and factors impacting it on a smaller scale, opening up a new horizon for more accurately formulating phosphorus management policies. The results showed that NAPI of the reservoir region maintained a high level (2641.84 kg·km−2·a−1), while showing significant spatial variation due to high input (>4200 kg·km−2·a−1) at an urban agglomeration in the reservoir region. Phosphorus fertiliser made the largest (63 %–64 %) contribution to NAPI in the reservoir region, but different compositions of the component determining NAPI were shown among the counties. The sensitive coefficient (2.36) of phosphorus fertiliser in the reservoir region was the largest, the sensitive coefficients and proportional contributions in counties also varied among the counties. The findings of this study showed that reducing the input of phosphorus fertiliser and improving the utilization rate of phosphorus are direct methods for reducing NAPI in the Three Gorges Reservoir Region. Furthermore, improving the methods of treating human domestic waste and sewage can alleviate the high input pressure of phosphorus. The spatial differentiation of NAPI in the analyzed counties was mainly affected by the increase in phosphorus fertiliser and gross output value of agriculture, along with increasing urbanization, population densification, and greater economic activity in Chongqing compared with the other counties. Moreover, the components, sensitivities, contributions and impact factors in the counties were heterogeneous due to socio-economic, agricultural, and geographical characteristics, so it might be more appropriate to formulate phosphorus management policies on a smaller county-based scale.