Hasil untuk "Ocean engineering"

Xiangsheng Deng, Huimin Lu, Yuehong Liu et al.

Root exudation is a key interface in plant-soil interactions and strongly influences nutrient cycling within orchard ecosystems. However, how root exudation varies with orchard age and what ecological factors drive these shifts remain insufficiently understood. Therefore, we quantified the relationships between root exudation and root traits, rhizosphere soil properties, and microbial biomass across a six-age orchard chronosequence of Citrus reticulata 'Chachi'. We found that the specific root length (SRL), root tissue density (RTD), specific root tip number (RTN), and root nitrogen concentration (RN) increased with orchard age, whereas the root diameter (RD), root carbon concentration (RC), and the root C:N ratio decreased. Principal component analysis (PCA) revealed that root traits varied significantly along the orchard-age gradient on PC1. Root exudation rates also differed significantly among orchard ages (p < 0.05) and were most strongly associated with soil dissolved organic carbon (DOC) and the DOC:total dissolved nitrogen (TDN) ratio. Specifically, along the orchard-age gradient, the exudation rates of carbon (CEr), nitrogen (NEr), sugars (SEr), and organic acids (OAEr) initially increased and then decreased, with peaks at 3 or 5 years. However, root exudation was not significantly related to root chemical traits. Partial least squares path modeling (PLS–PM) further revealed that orchard age was associated with variation in root exudation both directly and indirectly through its influences on root traits, rhizosphere soil properties, and microbial biomass. With increasing orchard age, root traits became more strongly associated with variation in CEr, whereas NEr shifted from being primarily linked to soil nutrient availability to being more closely influenced by microbial biomass. These results suggest that soil nutrient availability and root traits jointly shape how strongly root exudation responds along the orchard-age gradient. These findings enhance our understanding of belowground C processes associated with root exudation along the orchard-age gradient and offer practical insights for fertilization strategies in long-term perennial orchard systems.

Chenchen Gao, Tianyuan Zheng, Qinpeng Chang et al.

Abstract Fresh groundwater lenses (FGLs) are important freshwater resources for offshore reclaimed islands. However, previous studies usually neglected the dynamic evolution process of FGLs, which can last for decades in thin reclaimed islands. This study employed numerical simulation to analyze the morphology and volumetric evolution of FGLs in a saltwater‐filled reclaimed island. We found that the FGL could develop into an irregular pattern in its decades‐long evolution process, with the radius‐to‐thickness ratio of the island aquifer playing a critical role in shaping FGL morphology. When the ratio is below 29.7, the FGL fully develops into a regular lens‐like shape, characterized by a thick center and thinner edges. Conversely, high ratio leads to an irregular, basin‐like FGL formation. The periphery of the irregular FGL initially contacts the aquifer base, leaving significant residual saltwater at the island's center. At this point, the growth rate of the freshwater volume is maximized. An increase in hydraulic conductivity delays the appearance of irregular FGL formation and accelerates the removal of residual saltwater. When longitudinal dispersivity exceeds 5 m, freshwater firstly forms at the periphery of the island; otherwise, it predominantly forms at the center. Furthermore, increased recharge rates notably accelerate freshwater formation and increase the proportion of freshwater volume. These findings provide new insights into the hydrodynamic mechanisms driving irregular FGL evolution and offer technical support for optimizing fresh groundwater resource utilization on reclaimed islands.

Zhicheng Zhao, Qing Gao, Jinquan Yan et al.

Synthetic Aperture Radar (SAR) image interpretation has attracted widespread attention in remote sensing applications. However, the performance of existing methods is severely hindered by inherent limitations of SAR imaging mechanisms, such as speckle noise and low resolution. With the continuous advancement of remote sensing, it has become increasingly feasible to simultaneously acquire optical and SAR images. Given rich details in optical images, it is crucial to exploit this valuable information to guide quality enhancement of SAR images, thereby significantly improving their performance for practical applications. In this work, we propose a novel Hierarchical Selective Fusion Mamba Network (HSFMamba) for optics-guided joint super-resolution and denoising of SAR images, which simultaneously addresses resolution limitations and noise corruption in a unified framework. HSFMamba leverages the long-range modeling capability of the state space model with linear complexity and incorporates optical images through two progressive cross-selection scan mechanisms to perform high-quality reconstruction of SAR images corrupted by speckle noise. Specifically, we design a cross-modal feature selection module that dynamically identifies significant representations in optical images, thereby progressively extracting key information. To further leverage optical details while mitigating SAR speckle noise, we develop a frequency-spatial adaptive aggregation module aimed at better restoring image details, effectively enhancing critical high-frequency information. Additionally, we construct a well-aligned and high-resolution dataset for optics-guided joint SAR image super-resolution and denoising, comprising 3,200 optical-SAR image pairs, totaling 25,600 pairs across eight degradation modes. Extensive experiments demonstrate that HSFMamba effectively utilizes optical information to improve SAR image quality, outperforming several state-of-the-art methods.

Nana Jiang, Wenbo Zhao, Jiao Guo et al.

High-quality labeled samples of polarimetric synthetic aperture radar (PolSAR) images are relatively scarce. Therefore, achieving optimal classification performance with limited labeled samples has become a significant challenge in PolSAR image classification tasks. Existing deep learning methods not only rely on large amounts of labeled samples but also often face limitations in classification accuracy when handling multiinstance PolSAR image classification tasks. In response to this challenge, we propose a few-shot PolSAR image classification method based on dense bootstrap contrastive learning with 3-D dynamic convolution (DBCL-3DDC). The design of 3DDC enhances the feature extraction ability of the network for complex data. The DBCL learns global and local representations in a 30% and 70% ratio respectively, heuristically extracting feature representations for multiinstance PolSAR images. More importantly, during the pretraining phase, we design a multilevel contrastive learning strategy that fully utilizes both global and local instance representations without requiring labeled samples. The effectiveness of the proposed method is validated through experiments on three different datasets. Notably, on the Flevoland 1989 dataset, DBCL-3DDC achieves an overall accuracy of 97.29% using only 0.2% of labeled samples.

Nerea Portillo Juan, Vicente Negro Valdecantos

Mengmeng Wang, Bai Zhu, Jiacheng Zhang et al.

Deep learning techniques for change detection have undergone rapid development in the past few years. However, it is still a challenge how to reduce massive network parameters and sufficiently fuse bitemporal image features to improve detection accuracy. Therefore, this work proposes a novel and lightweight network based on feature interleaved fusion and bistage decoding (FFBDNet) for change detection. In the encoding stage, considering the application problems caused by a large number of network parameters, we use the more efficient EfficientNet as the backbone to extract the bitemporal image features based on Siamese architecture. To fuse the bitemporal image features and reduce interference from surrounding objects, we propose a feature interleaved fusion module, which can interleave the shared feature information and the difference variance feature information. During the decoding stage, the fused features are split into two groups, and a novel bistage decoding framework is proposed to generate the accuracy change map gradually. Extensive experiments and ablation studies are validated on three public change detection datasets: WHU-CD, LEVIR-CD, and SYSU-CD datasets. Compared to state-of-the-art methods, the experimental results demonstrate that the proposed FFBDNet produces a better balance between performance and model parameters. Specifically, the F1 values obtained for these three datasets are 93.27&#x0025;, 91.11&#x0025;, and 80.10&#x0025;, respectively, and the model parameters of the network are just 2.85 M.

Wen Lai, Xiumian Hu, Xiaolong Dong et al.

Abstract As a hot topic in Earth sciences, the Qinghai‐Tibet Plateau has accumulated a large amount of sedimentary‐related data. We constructed a dataset of detrital components for Qinghai‐Tibet Plateau from 63 peer‐reviewed publications. The dataset thus comprises 1813 Late Proterozoic to Pleistocene sandstones from 84 stratigraphic units. For each sample, we present details on reference, detrital composition, GPS, geographic location, depositional age, tectonic setting and depositional environment. It becomes a high‐quality dataset after the information on each sandstone sample was standardized and reviewed by sedimentary experts. The dataset can be used for regional geoscience studies, exploring the general laws of the source‐to‐sink process. The dataset may also be useful in the field of utilities, such as assisting in finding suitable building stones, helping oil and gas and mineral exploration, and so forth.

Shaojian Yang, Yi Lu, Yan Wei et al.

With the rapid advancement of underwater communication and unmanned aerial vehicle (UAV) technologies, the potential applications of cross-medium communication in environmental monitoring, maritime Internet of Things (IoTs), and rescue operations, in particular, have attracted great attention. This study explores the feasibility of achieving cross-medium direct acoustic communication through the air–water interface. Specifically, it investigates challenges such as acoustic impedance mismatches and signal attenuation caused by energy loss during interface transmission, aiming to understand their impact on communication performance. Experimental tests employed underwater acoustic transducers as signal transmitters to propagate sound waves directly into the air, attempting to establish communication links with aerial UAV nodes. Preliminary experimental results indicate that even conventional underwater acoustic transducers can achieve information exchange between underwater nodes and UAVs, laying a foundation for further research and application of cross-medium communication systems.

Dongen Guo, Zhuoke Zhou, Fengshuo Guo et al.

Remote sensing image (RSI) target detection methods based on traditional multiscale feature fusion (MSFF) have achieved great success. However, the traditional MSFF method significantly increases the computational cost during model training and inference, and the simple fusion operation may lead to the semantic confusion of the feature map, which cannot realize the refined extraction of features by the model. In order to reduce the computational effort associated with the MSFF operation and to enable the features in the feature map to present an accurate, fine-grained distribution, we propose a single-stage detection model (RS-YOLO). Our main additions to RS-YOLO are a computationally smaller and faster Quick and Small E-ELEN (QS-E-ELEN) module and a feature refinement extraction (FRE) module. In the QS-E-ELEN module, We utilize QSBlock, jump-join, and convolution operations to fuse features on different scales and reduce the computational effort of the model by exploiting the similarity of the RSI feature map channels. In order for the model to better utilize the enhanced features, we designed the FRE module to make the location of the enhanced features more accurate and fine. By conducting experiments on the popular NWPU-VHR- 10 and SSDD datasets, we derive results showing that RS-YOLO outperforms most mainstream models in terms of the tradeoff between accuracy and speed. Specifically, in terms of accuracy, it improves 1.6<inline-formula><tex-math notation="LaTeX">$\%$</tex-math></inline-formula> and 1.7<inline-formula><tex-math notation="LaTeX">$\%$</tex-math></inline-formula> compared to the current state-of-the-art models, respectively. At the same time, RS-YOLO reduces the number of parameters and computational effort.

Jiran Zhang, Lingling Zhang, Panpan Ren et al.

This article simulates the indoor useful daylight illuminance (UDI), energy consumption, and power generation of photovoltaic (PV) window buildings using EnergyPlus simulation software. Extensive data on these simulation parameters are obtained using parametric simulation software and combined with actual meteorological data. The factors significantly influencing PV window building performance are determined based on ANOVA. A model is developed to predict energy consumption, power generation, and UDI of PV window buildings using a back propagation neural network. For better lighting quality, lower energy consumption, and greater power generation, NSGA-II is introduced to optimize the windows' performance with multi-objective parameters. Moreover, the resulting energy saving rate, annual average power generation growth rate, and UDI growth rate are compared with the initial values to evaluate the effectiveness of the optimal solution. The results demonstrate that the energy saving rate of the building is 18.23 %, and the growth rates of the useful daylight illuminance and power generation reach 41.6 % and 5.12 %, respectively, compared to the initial values.

O. Marquis, B. Tremblay, J.-F. Lemieux et al.

<p>The viscous–plastic (VP) rheology with an elliptical yield curve and normal flow rule is implemented in a Lagrangian modelling framework using the smoothed particle hydrodynamics (SPH) meshfree method. Results show, from a perturbation analysis of SPH sea-ice dynamic equations, that the classical SPH particle density formulation expressed as a function of sea-ice concentration and mean ice thickness leads to incorrect plastic wave speed. We propose a new formulation for particle density that gives a plastic wave speed in line with theory. In all cases, the plastic wave in the SPH framework is dispersive and depends on the smoothing length (i.e., the spatial resolution) and on the SPH kernel employed in contrast to its finite-difference method (FDM) implementation counterpart. The steady-state solution for the simple 1D ridging experiment is in agreement with the analytical solution within an error of 1 %. SPH is also able to simulate a stable upstream ice arch in an idealized domain representing the Nares Strait in a low-wind regime (5.3 <span class="inline-formula">m s⁻¹</span>) with an ellipse aspect ratio of 2, an average thickness of 1 <span class="inline-formula">m</span> and free-slip boundary conditions in opposition to the FDM implementation that requires higher shear strength to simulate it. In higher-wind regimes (7.5 <span class="inline-formula">m s⁻¹</span>) no stable ice arches are simulated – unless the thickness is increased – and the ice arch formation showed no dependence on the size of particles, in contrast to what is observed in the discrete-element framework. Finally, the SPH framework is explicit, can take full advantage of parallel processing capabilities and shows potential for pan-Arctic climate simulations.</p>

Sujantoko Sujantoko, Widi Agus Pratikto, Rudi Waluyo Prastianto et al.

Surabaya is a coastal area projected to be a strategic area for the sustainable development of coastal areas according to the medium-term development plan for Surabaya 2016-2021. The strategic area of the coastal area functions as a supporter of economic growth and saving the environment to optimize the development of the coastal area, so a study is needed to determine the development of the area. This study was conducted to determine the strengths, weaknesses, opportunities and threats in the coastal area of Surabaya. The researcher took a qualitative approach to the analysis and was the necessary case study. Analysis of this activity using the SWOT method. The SWOT analysis results from a comparison of internal and external factors; the analysis is carried out using the IFAS (Internal Factor Analysis Summary) matrix and the EFAS (External Factor Analysis Summary) matrix. Based on the SWOT analysis, it can be shown that the management of the Surabaya City coastal area is by the spatial plans that have been made. However, in reality, it must pay attention to communication and socialization with the community, which is considered not optimal, as well as periodic impact management and environmental maintenance to minimize coastal threats.

Z. Sun, Z. Sun, Z. Sun et al.

<p>The nitrogen stable isotope composition (<span class="inline-formula"><i>δ</i>¹⁵</span>N) of nitrogen oxides (NO<span class="inline-formula">_<i>x</i>)</span> is a powerful indicator of source apportionment of atmospheric NO<span class="inline-formula">_<i>x</i></span>; however, <span class="inline-formula"><i>δ</i>¹⁵</span>N–NO<span class="inline-formula">_<i>x</i></span> values emitted from ships have not been reported, affecting the accuracy of source partitioning of atmospheric NO<span class="inline-formula">_<i>x</i></span> in coastal zones with a lot of vessel activity. In addition, <span class="inline-formula"><i>δ</i>¹⁵</span>N–NO<span class="inline-formula">_<i>x</i></span> values from ship emissions could also be important for source apportionment of atmospheric nitrogen deposition in remote ocean regions. This study systemically analysed the <span class="inline-formula"><i>δ</i>¹⁵</span>N–NO<span class="inline-formula">_<i>x</i></span> variability and main influencing factors of ship emissions. The results showed that <span class="inline-formula"><i>δ</i>¹⁵</span>N–NO<span class="inline-formula">_<i>x</i></span> values from ships, which were calculated by weighting the emission values from the main engine and auxiliary engine of the vessel, ranged from <span class="inline-formula">−</span>35.8 ‰ to 2.04 ‰ with a mean <span class="inline-formula">±</span> standard deviation of <span class="inline-formula">−</span>18.5 <span class="inline-formula">±</span> 10.9 ‰. The <span class="inline-formula"><i>δ</i>¹⁵</span>N–NO<span class="inline-formula">_<i>x</i></span> values increased monotonically with the ongoing tightening of emission regulations, presenting a significantly negative logarithmic relationship with NO<span class="inline-formula">_<i>x</i></span> concentrations (<span class="inline-formula"><i>p</i>&lt;0.01</span>). The selective catalytic reduction (SCR) system was the most important factor affecting changes in <span class="inline-formula"><i>δ</i>¹⁵</span>N–NO<span class="inline-formula">_<i>x</i></span> values, followed by the ship category, fuel types, and operation states of ships. Based on the relationship between <span class="inline-formula"><i>δ</i>¹⁵</span>N–NO<span class="inline-formula">_<i>x</i></span> values and emission regulations observed in this investigation, a mass-weighted model to compute accurate assessments over time was developed, and the temporal variation in <span class="inline-formula"><i>δ</i>¹⁵</span>N–NO<span class="inline-formula">_<i>x</i></span> values from ship emissions in the international merchant fleet was evaluated. These simulated <span class="inline-formula"><i>δ</i>¹⁵</span>N–NO<span class="inline-formula">_<i>x</i></span> values can be used to select suitable <span class="inline-formula"><i>δ</i>¹⁵</span>N–NO<span class="inline-formula">_<i>x</i></span> values for a more accurate assessment, including the contribution of ship-emitted exhaust to atmospheric NO<span class="inline-formula">_<i>x</i></span> and its influence on atmospheric nitrate (NO<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M36" display="inline" overflow="scroll" dspmath="mathml"><mrow><msubsup><mi/><mn mathvariant="normal">3</mn><mo>-</mo></msubsup><mo>)</mo></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="12pt" height="16pt" class="svg-formula" dspmath="mathimg" md5hash="5cff292f284d562dc6d0310a4128574e"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-23-12851-2023-ie00001.svg" width="12pt" height="16pt" src="acp-23-12851-2023-ie00001.png"/></svg:svg></span></span> air quality and nitrogen deposition studies.</p>

Yingna Mu, Yingna Mu, Qibing Hu et al.

To ensure the safe operation of bridges, the study of methods and techniques for boom replacement has become a crucial aspect of the scientific maintenance of suspension bridges. This study focuses on analyzing the bridge responses and evaluating the applicability of three different boom replacement methods: single-point, three-point and five-point, using finite element calculations. A sea-crossing suspension bridge is taken as a case study to simulate the process of boom replacement using temporary booms. Consequently, the optimal replacement method for booms of varying lengths is determined. Meanwhile, this research proposes a quantitative basis for classifying boom lengths based on calculation data and analysis results to determine the suitable boom lengths for different replacement methods. Besides, a comparison of the relationship between the force transmission efficiency of temporary booms and boom length reveals that longer booms exhibit lower force transmission efficiency, with the efficiency decreasing at a faster rate as boom length increases. Overall, these findings provide a theoretical basis for the study of boom replacement in suspension bridges.

Jun-Yup Park, Jong-Yeon Jung, Yu-Taek Seo

While extensive research is being conducted to reduce greenhouse gases in industrial fields, the International Maritime Organization (IMO) has implemented regulations to actively reduce CO2 emissions from ships, such as energy efficiency design index (EEDI), energy efficiency existing ship index (EEXI), energy efficiency operational indicator (EEOI), and carbon intensity indicator (CII). These regulations play an important role for the design and operation of ships. However, the calculation of the index and indicator might be complex depending on the types and size of the ship. Here, to calculate the EEDI of two target vessels, first, the ships were set as Deadweight (DWT) 50K container and 300K very large crude-oil carrier (VLCC) considering the type and size of those ships along with the engine types and power. Equations and parameters from the marine pollution treaty (MARPOL) Annex VI, IMO marine environment protection committee (MEPC) resolution were used to estimate the EEDI and their changes. Technical measures were subsequently applied to satisfy the IMO regulations, such as reducing speed, energy saving devices (ESD), and onboard CO2 capture system. Process simulation model using Aspen Plus v10 was developed for the onboard CO2 capture system. The obtained results suggested that the fuel change from Marine diesel oil (MDO) to liquefied natural gas (LNG) was the most effective way to reduce EEDI, considering the limited supply of the alternative clean fuels. Decreasing ship speed was the next effective option to meet the regulation until Phase 4. In case of container, the attained EEDI while converting fuel from Diesel oil (DO) to LNG was reduced by 27.35%. With speed reduction, the EEDI was improved by 21.76% of the EEDI based on DO. Pertaining to VLCC, 27.31% and 22.10% improvements were observed, which were comparable to those for the container. However, for both vessels, additional measure is required to meet Phase 5, demanding the reduction of 70%. Therefore, onboard CO2 capture system was designed for both KCS (Korea Research Institute of Ships & Ocean Engineering (KRISO) container ship) and KVLCC2 (KRISO VLCC) to meet the Phase 5 standard in the process simulation. The absorber column was designed with a diameter of 1.2–3.5 m and height of 11.3 m. The stripper column was 0.6–1.5 m in diameter and 8.8–9.6 m in height. The obtained results suggested that a combination of ESD, speed reduction, and fuel change was effective for reducing the EEDI; and onboard CO2 capture system may be required for Phase 5.

Yunlong PANG, Tingting WANG, Huabin SHAO et al.

Marine ecological civilization is the concentrated embodiment of ecological civilization thought in marine field, is the innovation and development in the process of marine governance in China. Since ecological civilization was included in the overall plan of "five-in-one" socialist cause with Chinese characteristics, ecological civilization construction has been raised to an unprecedented height. The ocean is an important area of the country′s overall ecological civilization construction. The core of marine ecological civilization is people-centered, so as to realize overall planning on land and sea and harmony among people, and promote the building of a maritime power. In view of this, this paper puts forward the view of coordinated development of marine ecological civilization, and takes Jiaodong as an example to analyze the basic conditions for the coordinated development of marine ecological civilization in five cities of Jiaodong. At the same time, the index system of the coordinated development of marine ecological civilization is constructed, and the level of the coordinated development of regional marine ecological civilization is comprehensively evaluated, in order to expand the achievements of marine ecological civilization construction and provide a new perspective and approach for the regional coordinated development.

Janusz T. Cieśliński

A comprehensive review of published works dealing with numerical modelling of forced convection heat transfer and hydrodynamics of nanofluids is presented. Due to the extensive literature, the review is limited to straight, smooth, circular tubes, as this is the basic geometry in shell-and-tube exchangers. Works on numerical modelling of forced convection in tubes are presented chronologically in the first part of the article. Particular attention was paid to the method of the solution of governing equations, geometry of the heating section, and boundary conditions assumed. Influence of nanoparticles on heat transfer and flow resistance are discussed. Basic information is summarized in tabular form, separately for single-phase approach and two-phase models. The second part of the article contains the correlation equations proposed in the presented papers for the calculation of the Nusselt (Nu) number or heat transfer coefficient, separately for laminar and turbulent flow. Details of the type of nanofluids, the concentration of nanoparticles, and the Reynolds (Re) number range are also presented. Finally, advantages and disadvantages of individual numerical approaches are discussed.

Ho-Jong Kim, Yong Ju Yun, Sam Nyung Yi et al.

Maxime M. Grand, Agathe Laes-Huon, Susanne Fietz et al.

Trace metal micronutrients are integral to the functioning of marine ecosystems and the export of particulate carbon to the deep ocean. Although much progress has been made in mapping the distributions of metal micronutrients throughout the ocean over the last 30 years, there remain information gaps, most notable during seasonal transitions and in remote regions. The next challenge is to develop in situ sensing technologies necessary to capture the spatial and temporal variabilities of micronutrients characterized with short residence times, highly variable source terms, and sub-nanomolar concentrations in open ocean settings. Such an effort will allow investigation of the biogeochemical processes at the necessary resolution to constrain fluxes, residence times, and the biological and chemical responses to varying metal inputs in a changing ocean. Here, we discuss the current state of the art and analytical challenges associated with metal micronutrient determinations and highlight existing and emerging technologies, namely in situ chemical analyzers, electrochemical sensors, passive preconcentration samplers, and autonomous trace metal clean samplers, which could form the basis of autonomous observing systems for trace metals within the next decade. We suggest that several existing assets can already be deployed in regions of enhanced metal concentrations and argue that, upon further development, a combination of wet chemical analyzers with electrochemical sensors may provide the best compromise between analytical precision, detection limits, metal speciation, and longevity for autonomous open ocean determinations. To meet this goal, resources must be invested to: (1) improve the sensitivity of existing sensors including the development of novel chemical assays; (2) reduce sensor size and power requirements; (3) develop an open-source “Do-It-Yourself” infrastructure to facilitate sensor development, uptake by end-users and foster a mechanism by which scientists can rapidly adapt commercially available technologies to in situ applications; and (4) develop a community-led standardized protocol to demonstrate the endurance and comparability of in situ sensor data with established techniques. Such a vision will be best served through ongoing collaborations between trace metal geochemists, analytical chemists, the engineering community, and commercial partners, which will accelerate the delivery of new technologies for in situ metal sensing in the decade following OceanObs’19.

María Teresa Flórez Molina, Luis Norberto Parra Sánchez, Sandra Viviana Bolaños Benitez et al.

The sedimentology of three reservoirs of Empresas Públicas de Medellín, located in Antioquia, Colombia, showed high average sedimentation rates. In Riogrande II of 2.25 m year–1, in La Fe of 0.14 m year–1 and in Porce II of the order of 7.6 m year–1. In these reservoirs there are differences in the accumulation of sediments, the silts are concentrated in the stagnant and deeper areas while the sands in the inlets of the drainages to the reservoirs. There is a marked seasonal tendency of sedimentation with maximum values during the rainy months and there are spatio-temporal compositional and granulometric differences. A simulation of the sedimentary evolution of these three reservoirs indicates their possible disappearance as a deposit of water to continue the contributions of sediments from the tributaries, being more drastic in Porce II.