Basin System Research Articles

The Role of Razak Fault in Controlling the Sedimentary Basin and Hydrocarbon Systems in External Fars Region, Zagros, Iran

The Role of Razak Fault in Controlling the Sedimentary Basin and Hydrocarbon Systems in External Fars Region, Zagros, Iran

Tectonic-sedimentary evolution in a Palaeocene rifted Lishui Sag, East China Sea Shelf Basin

Influenced by episodic tectonic activity and multiple sediment sources, the source-to-sink systems in rifted basins are relatively complex. Based on seismic data, well logging, cores, thin sections, and heavy mineral data, the growth and linkage of the Lingfeng fault were reconstructed and its influence on the sedimentary responses of the Palaeocene-rifted Lishui Sag in the East China Sea Shelf Basin was examined. The researchers conducted a fault throw-distance analysis on the Lingfeng fault and found that it displayed an overall weak-strong-weak evolutionary process. During the early syn-rift stage, the Lingfeng fault exhibited a segmented geometry consisting of seven fault segments with low fault activity along its strike, and small-scale source-to-sink systems developed in both the hanging wall dip-slope and footwall. As the main syn-rift stage progressed, strong fault activity induced large-scale exposure of the source area, resulting in a high sediment-supply rate and large-scale source-to-sink systems. During the late syn-rift stage, the fault weakened and evolved into a connected basin-boundary fault, and proximal source-to-sink systems in the footwall gradually disappeared. Semi-quantitative measurements of the geomorphic parameters of these source-to-sink systems indicated wide and shallow sediment transport pathways in hanging wall dip-slope areas (average width and depth of approximately 6.34 kmand 0.13 km, respectively) and narrow and deep sediment transport pathways in the footwall (average width and depth of approximately 3.75 km and 0.15 km, respectively). The semi-quantitative statistical analysis implies that the cross-sectional area of the transport channels was positively correlated with the corresponding fan/delta complexes in a rift basin.

Evaluating Effects of Terraces on Flow Regimes in a Hilly and Mountainous Basin

Terraces play a crucial role in regulating the water cycle. The management and restoration of, and the conservation strategies and plans for basins rely heavily on the assessment of alterations in hydrological characteristics, whether natural or man-made, within these basin systems. This study centers on evaluating the impact of terraces on temporal variations in the hydrological regime within the Laixi River basin, within the context of climate variability. To achieve this, we employed a hydrological model and applied the Indicators of Hydrologic Alteration and Range of Variability Approach (IHA–RVA). The results show that, under the influence of terraces, the annual flow exhibited an overall decreasing trend. There was a noticeable decrease in streamflow from March to July, while from October to December, there was a clear upward trend, with increases ranging from 4.76% to 8.10% at the Guanshenxindi (GSXD) and Watershed outlet (WO) cross-sections. The indicators related to the minimum flow showed an overall increasing trend, whereas all indicators related to the maximum flow exhibited a clear decreasing trend. Both high and low flow pulse counts decreased, while high and low pulse durations increased overall. The overall trend of flow reversal counts also showed a decrease. All hydrological indicators exhibited low levels of alteration, with hydrologic alteration values lower than 33.33%. However, the influence of terraces on the upstream hydrological conditions was more pronounced than their downstream effect. The terraces in the study area have played a beneficial role in the flood regulation, drought mitigation, and water resource conservation of the Laixi River. They have contributed to stabilizing the daily average flow during high flow periods and have had a positive impact on the ecological base flow during low flow periods, thereby improving the aquatic ecological environment. This study provides theoretical support for river regulation within the framework of soil and water conservation measures.

Normal fault evolution in the Penghu Basin, a Paleogene Rift Basin in Western Taiwan Strait: A test of fault growth models

The growth of normal fault systems affects the development of rift basins. These systems could grow via either non-coherent or coherent models, where segments either develop independently or merge into one fault, respectively. Also, they could experience decreases in fault system lengths, called lateral tip retreat, during the later fault-activity stage. In this study, we investigate the fault growth model by studying the Penghu Basin, a Paleogene rift basin in the western Taiwan Strait, and test the current fault growth models. Our methods include seismic interpretation and fault growth analyses, such as the spatiotemporal distribution of cumulative throw and throw increment and expansion index. In the Penghu Basin, the boundary and transfer fault systems grew via the non-coherent model followed by lateral tip retreat, while other studied fault systems grew via the coherent model before their tips retreated. Furthermore, segments could separate from their parent fault systems prior to the lateral-tip-retreat stage. During the evolution of the fault system, the shifting of a cumulative throw maximum could be accompanied by a throw increment minimum, i.e., segmentation, moving toward the migrated cumulative throw maximum inside segments or by the retreated fault tip of the fault system. This implies a change in the distributions of stress drop and increase regions. Finally, our results indicate that the specific rift phase of basin evolution is highly correlated with the development of fault systems. We suggest that the lateral tip retreat of fault systems marks a change in the rift phase of a basin and implies the end of basin evolution.

An overview of groundwater response to a changing climate in the Murray-Darling Basin, Australia: potential implications for the basin system and opportunities for management

The Murray-Darling Basin (MDB) is a highly allocated and regulated, mostly semiarid basin in south-eastern Australia, where groundwater is a significant water resource. Future climate predictions for the MDB include an expansion of arid and semiarid climate zones to replace temperate areas. The impacts of climate change are already evident in declining groundwater levels and changes in the connection status between rivers and groundwater, and modelling has predicted a further reduction in future groundwater recharge and ongoing declines in groundwater levels. This is predicted to further reduce river baseflow and negatively impact groundwater-dependent ecosystems (GDEs), and these system responses to a changing climate and extreme events are complex and not always well understood. This report provides an overview of the current state of knowledge of groundwater response to a changing climate for the MDB, and outlines challenges and opportunities for future groundwater research and management. Opportunities for the region include improving data systems and acquisition through automation and novel data sources, and growing capability in integrated, risk-based modelling. Quantification of the groundwater/surface-water connection response to declining groundwater levels, and assessing GDE water requirements and thresholds, would enable identification of vulnerable systems and inform the development of metrics for adaptive management, improving the ability to respond to climate extremes. There is potential to adapt policy to support active management of groundwater where required, including conjunctive use and water banking. Improving knowledge sharing and water literacy, including understanding community values of groundwater and GDEs, would support future decision-making.

Tracing the origin of Lago Mare biota: Ostracods and mollusks from the late Neogene of the Slavonian mountains in the southern Pannonian Basin (NE Croatia)

Lake Pannon was a huge central European, long-lived endorheic lake occupying the Pannonian Basin System during the late Neogene. The benthic fauna of this originally sparsely populated brackish lake went through a spectacular adaptive radiation leading to a great number of autochthonous species. Although largely endemic, some of these species are excellent stratigraphic markers of the Lago Mare interval in the Mediterranean Basin. This situation apparently reflects a short-termed unidirectional migration-wave in the latest Miocene. The latter interval marks the final phase of a major environmental perturbation followed by a massive evaporite deposition termed the Messinian Salinity Crisis. The Section Bozara, located in the southern Pannonian Basin at the southern slopes of Mt. Papuk, bears a well-preserved benthic fauna representative of Lake Pannon. It is embedded into a 25-m-thick succession of alternating mud and sand packages. We detected therein 25 ostracod and 18 mollusk taxa enabling, along with a sedimentary facies analysis, an integrated evaluation of the depositional setting, biostratigraphic position, and paleogeographic distribution pattern. Accordingly, the depositional environment shows a shallowing upward trend from deep-water sublittoral and distal prodelta settings to deltaic high-energy littoral conditions. The biostratigraphic markers, such as the bivalve Rhombocongeria rhomboidea (Hörnes, 1867) and the ostracod Caspiocypris pontica (Sokač, 1972), constrained its stratigraphic position to the Portaferrian interval (8.0–4.5 Ma). Of 16 ostracod taxa determined at the species level, 10 are shared with the Eastern Paratethys, whereas only 3 are present in the Mediterranean Lago Mare deposits as well. In contrast, among 12 corresponding mollusk taxa, only 4 are known from the Eastern Paratethys, all being absent in the Lago Mare interval. Such a paleobiogeographic pattern suggests that the time window of the outflow event from Lake Pannon into the Eastern Paratethys was not synchronous with, but must have preceded, the hypothetic Eastern Paratethys drainage event generating the Lago Mare depositional conditions in the Mediterranean Basin.

Ecological mechanisms and current systems shape the modular structure of the global oceans’ prokaryotic seascape

Major biogeographic features of the microbial seascape in the oceans have been established and their underlying ecological mechanisms in the (sub)tropical oceans and the Pacific Ocean identified. However, we still lack a unifying understanding of how prokaryotic communities and biogeographic patterns are affected by large-scale current systems in distinct ocean basins and how they are globally shaped in line with ecological mechanisms. Here we show that prokaryotic communities in the epipelagic Pacific and Atlantic Ocean, in the southern Indian Ocean, and the Mediterranean Sea are composed of modules of co-occurring taxa with similar environmental preferences. The relative partitioning of these modules varies along latitudinal and longitudinal gradients and are related to different hydrographic and biotic conditions. Homogeneous selection and dispersal limitation were identified as the major ecological mechanisms shaping these communities and their free-living (FL) and particle-associated (PA) fractions. Large-scale current systems govern the dispersal of prokaryotic modules leading to the highest diversity near subtropical fronts.

Flood Simulation Using HEC-HMS 4.8 for Ungauged Catchment During Extreme Events in Lui River, Hulu Langat

Flooding is a sort of natural disaster that can occur anywhere in the world. It is also happening more often now because of global warming and climate change. The Department of Irrigation and Drainage (DID) has designated certain sites along the Lui River in Hulu Langat as flood-prone. Therefore, this study presents a hydrological simulation of the Lui River utilising the flood management software on the Hydrologic Modelling System, HECHMS 4.8, which has been widely used in several studies of water management. The program replicates a river basin system's rainfall-runoff response to a precipitation input by modelling the whole river basin as an integrated system of hydrologic and hydraulic components, displaying the trends in the river's flow for 50 ARI and 100 ARI. The hydrograph of the Lui River may be determined by examining the rainfall-runoff relationship and comparing it to the peak discharge of observed data and the hydrograph for an unmeasured watershed from Hydrological Procedure No. 11. The hydrograph result must undergo model calibration to establish parameters that are validated for the model final value of peak discharge and the shape of the hydrograph. The finding shows that the optimal design hydrograph for the design stage is the model's hydrograph with the greatest peak as in HEC-HMS. Hence, the design storm with the largest output will serve as a guideline for any design matter, be valuable for future river flow research, and function as a future precaution.

The Budyko shape parameter as a descriptive index for streamflow loss

Increases in evapotranspiration (ET) from global warming are decreasing streamflow in headwater basins worldwide. However, these streamflow losses do not occur uniformly due to complex topography. To better understand the heterogeneity of streamflow loss, we use the Budyko shape parameter (ω) as a diagnostic tool. We fit ω to 37-year of hydrologic simulation output in the Upper Colorado River Basin (UCRB), an important headwater basin in the US. We split the UCRB into two categories: peak watersheds with high elevation and steep slopes, and valley watersheds with lower elevation and gradual slopes. Our results demonstrate a relationship between streamflow loss and ω. The valley watersheds with greater streamflow loss have ω higher than 3.1, while the peak watersheds with less streamflow loss have an average ω of 1.3. This work highlights the use of ω as an indicator of streamflow loss and could be generalized to other headwater basin systems.

A SYNTHESIS OF THE GEOLOGY AND PETROLEUM GEOLOGY OF THE IRANIAN PORTION OF THE SOUTH CASPIAN BASIN AND SURROUNDING AREAS

The South Caspian Basin, the northern Alborz Mountains, the Gorgan plain and the Moghan plain constitute the northernmost and youngest petroleum system in Iran. This region was part of the Paratethys realm from Oligocene to Pliocene time. The Oligocene – Miocene Maikop/Diatom Total Petroleum System of the South Caspian Basin produces major volumes of hydrocarbons in Azerbaijan and Turkmenistan, and the Iranian sector of the basin has consequently undergone exploration due to its generally similar geology. The 20 km thick, dominantly Cenozoic sedimentary cover in the basin is reduced to less than 3 km in the northern foothills of the Alborz Mountains, and scattered surface oil seepages in the latter region are believed to be generated by Cretaceous and Miocene source rocks. In the Moghan plain to the southwest of the South Caspian Basin, anticlinal folds of Oligo‐Miocene Zivar Formation sandstones may be prospective for hydrocarbon exploration. Mud volcanoes in the Gorgan plain and in adjacent offshore regions at the SE margin of the South Caspian Basin are associated with hydrocarbon seepages, and appear to be sourced by Cretaceous and Cenozoic shales and mudstones. Major structural features in the southern part of the South Caspian Basin include Cenozoic mud diapirs, folds and gravity structures.

Pit lakes from gravel and sand quarrying in the Po River basin: An opportunity for riverscape rehabilitation and ecosystem services improvement

Since the 1950s, an intense sand and gravel quarrying from the river floodplains led to the formation of pit lakes (PLs) that have changed the morphology and the drainage system of several Italian river basins. In the last decade, a renewed interest in PLs has grown as tools for rehabilitating rivers and their floodplains, in order to provide a similar ecological service once offered by pristine riverine wetlands, which were lost due to anthropogenic pressures. The primary aim of this study was to quantify the number, distribution, and major morphometric characteristics of these ecosystems in the Po River basin, in order to assess their relevance and suitability for ecological restoration purposes. To achieve this aim, a synergistic approach was used including remote sensing techniques, satellite archives, and regional databases. The results show that more than 12,650 small lentic water bodies are present in the Po River basin, with agricultural ponds the most represented category, followed by PLs. Specifically, 1580 PLs were identified, divided into three subcategories: active (338), ceased (1188) and doubtful (54). These artificial ecosystems, when compared with pristine riverine wetlands, are more numerous, widely distributed, and on average more extensive, although more regularly shaped. The temporal analysis of satellite imagery showed that the number and the total area of PLs have increased from 1990 to 2021. PLs currently account for 63.5 km2 surface area, an average water volume of 378 × 106 m3 and for a removal of 26.6 mg N m−2 d−1 via denitrification. Therefore, PLs can contribute ecosystem services, e.g., water provisioning and regulation of the nitrogen cycle, and can be exploited for rehabilitating the riverscape. In this context, remote sensing is a very reliable tool for quantifying and analysing PLs and others water bodies in a vast area such as the Po River basin.

Evaluating main drivers of terrestrial water storage depletion in the agro-pastoral ecotone of northern China

With the heightened threat of declining terrestrial groundwater, determining the effects of changing environments on terrestrial water storage anomaly (TWSA) is essential for water resource management. As a critical element of the water cycle, the multi-effects of the natural and artificial factors on TWSA were still not fully understood and quantified. Using multiple high-resolution data products and the structural equation model (SEM), this study discussed how climate, vegetation, and human activities affected terrestrial water storage (TWS) in the West Liao River basin (WLRB), China, from 1990 to 2020. The results confirmed that vegetation showed a greening trend while TWS depleted at 5.93 cm/10a in the WLRB. TWS in greening areas has a negative correlation with vegetation growth. The decline in TWS is mainly dominated by precipitation and runoff variability. By influencing eco-hydrological cycle processes, climate change and human activities affect TWS through direct and indirect(by influencing NDVI) pathways. Land use change, manifested as conversion of grassland into cropland, contributed to the most decline of TWS (51.2 %). Moreover, the crop yield increasing, climate warming, and vegetation greening could lead to TWS depletion. Spatially, the overexploitation of the groundwater for irrigation to support crop production was probably the most critical cause of TWS depletion over upstream of the WLRB. Furthermore, in the West Liao Plain, the intensified vegetation greenness also led to the increasing ecosystem water demand, resulting in the decrease of TWS. This study improves our understanding of the interaction of the basinal eco-hydrological system and provides a hint that reducing groundwater extraction and implementing agriculture fallow is essential to recovering water storage and alleviating the water resource crisis in the agro-pastoral ecotone.

ON THE QUESTION OF USING GIS TOOLS IN THE STUDY OF PALEOVALLEY IN THE VERCHNY PRUT BASIN

This article is devoted to the complex issue of the use of GIS in the study of the stages of the formation of the water network of the rivers of the Ukrainian Carpathians, the identification and study of ancient flow valleys, morphogenesis and features of high terrace levels and paleovalleys in different periods of their formation. It is the use of new modern methods of digital mapping and geo-informational tools in research that allows us to look in a new way at the seemingly already known and defined problematic issues of the clarity of the stages of the origin and formation of the basins of the river systems of the Ukrainian Carpathians and their gradual stabilization within modern limits. It would seem that the position of leading specialists, Ukrainian geomorphologists (P. M. Tsis, K. I. Gerenchuk, M. S. Kozhurinoi, Y.S. Kravchuk, V. M. Klapchuk and others) has been clearly formulated for a long time thanks to the use of new geoinformation technologies and accessibility to modern software opens up new opportunities for its review and refinement. Currently, an important aspect of the study of basin systems of mountain regions, such as the territory of the Ukrainian Carpathians, is the application of not just a cartographic research method, with the corresponding results of visualization, zoning or the creation of appropriate map schemes, but the use of system analysis, thanks to GIS applications (TIN interpolation qgis) and the creation of appropriate models, which allows us to reveal in more detail the complex issues of the transformation of ancient valleys and their modern reflection in the relief of this territory. It is the ambiguous conclusions and results of previous researchers that encourage the use of new, more progressive methods, which will make it possible to better substantiate and determine how the processes of restructuring of the river network of the southeastern macroslope of the Ukrainian Carpathians took place, as well as to reveal the reasons for these changes. It is especially important to take into account and rely on changes in the configuration of the Upper Prut river system network at various stages of its functioning and development. This complex and not fully resolved issue, the transformation of ancient flow valleys in the Pliocene–Pleistocene period, is extremely important for the understanding of modern channel processes on the rivers of the Upper Pruth basin, as it still has a significant impact on the perception of the modern view of the river network of the studied basin and the inherited nature of macroforms riverbed in its separate sections. Keywords: GIS; digital topographic base of the Earth: SRTM; paleogeomorphological analysis; paleovalley Chornyy Cheremosh river; paleovalley Chornа Tysa river; paleovalley of the Lyuchka and Oslava rivers.

Agricultural activity on the Mun River basin: insight from spatial distribution and sources of dissolved rare earth elements in northeast Thailand.

Rare earth elements (REE) are emerging pollutants of concern, impacted by intensive fertilizer use and discharge of human and animal waste into agricultural watersheds. However, the natural values and potential anthropogenic enrichment of REE in aqueous systems of the agricultural basins remain poorly understood. This study investigated the spatial variation of dissolved REE in a predominantly agricultural river (Mun River) in northeast Thailand. Dissolved ΣREE concentrations in the Mun River ranged from 5.08 to 272.91 ng/L, with the highest concentrations observed in the middle reaches where agricultural fertilizers and wastewater increased dissolved REE concentrations. The PAAS-normalized patterns and dissolved Eu anomaly jointly reveal that the dissolved ΣREE mainly originated from local rocks and agricultural fertilizers. The dissolved REE in the Mun River is characteristic of a depleted light REE relative to heavy REE, slightly negative Ce anomaly, positive Eu anomaly, and positive Gd anomaly in a punctate distribution. The correlation analysis of (La/Yb)N with fluvial pH and HCO3- indicates that the water environment characteristics of the Mun River control dissolved REE fractionation. The Ce anomaly is associated with the oxidation environment, whereas the Eu anomaly is linked to the lithologic inheritance. Positive punctate Gd anomalies are influenced by human-caused wastewater discharge and applying fertilizers, raising Gd concentrations beyond natural background levels. This study has suggested that the geochemical characteristics of dissolved REE are affected by agricultural disturbances, and future environmental research on dissolved REE is essential to clarifying the impacts of REE on agriculture, the environment, and human health.

Quantifying the Effects of Climate Change on Simineh River Discharge in Lake Urmia Basin

The Simineh River is heavily reliant on water resources for agricultural aims in the Lake Urmia. However, the hydrological system of the Simineh basin is highly susceptible to the impacts of climate change scenarios, primarily due to the presence of diverse topographical features, limited availability of data, and the complex nature of the local climate. This study aimed to simulate the monthly discharge of the Simineh River using the SWAT and assess the effects of climate change on the monthly discharge. Future climate scenarios for the years 2011-2030 were generated using the HadCM3 weather models under the A2, B1, and A1B scenarios. After evaluating the performance of the LARS-WG model in producing precipitation, minimum and maximum temperatures for the Simineh River watershed, the output of the HadCM3 under the A1B, B1, and A2 scenarios reduced, and the desired meteorological parameters predicted. These predicted values used as inputs for the SWAT model. In this study, assuming no change in land use, the focus was solely on the impact of climate change scenarios. However, appropriate measures can be taken to save the Simineh River's water consumption by optimizing irrigation efficiency through innovative methods. This is crucial because the results indicate that a total reduction of up to 25% in discharge in the Lake Urmia basin under climate change leads to a significant decrease in the annual average inflow to the lake from 570 million cubic meters to 394, 398, and 440 million cubic meters under the A2, B1, and A1B scenarios, respectively. The Simineh River supplies 11% of the water in Lake Urmia, and taking necessary measures to conserve its water resources is essential.

Depositional model of clastic and carbonate rocks in a continental rift basin: a case study of the Paleogene Shahejie Formation in the Cangdong Depression, Bohai Bay Basin

The study of a clastic and carbonate rock depositional model in a continental rift basin is helpful to better understand the sedimentary processes active in continental rift basins. However, the spatiotemporal evolution characteristics and controlling factors of clastic and carbonate rocks in continental rift basins are still unclear. Therefore, the sedimentary characteristics of the clastic and carbonate rocks in the Paleogene Eocene Shahejie Formation (Es) are analysed via seismic, well log, core, thin section, and geochemistry data. Then, the impacts of tectonic movement, sediment supply and hydrologic conditions on sedimentary characteristics are discussed, and a depositional model is finally established. Five 3rd-order sequences, named SQ1–SQ5 from bottom to top, are identified in the Es. Fan delta, braided delta, meandering river delta, and lake sedimentary systems are identified in the Es; clastic rock sedimentary systems are identified in SQ1–SQ4, while concurrent clastic and carbonate rock sedimentary systems are identified in SQ5. During the SQ1–SQ4 period, the palaeogeomorphology formed by differential faulting activity or fault interactions and the inherited palaeogeomorphology resulted in different distributions of the sedimentary systems. The changes in accommodation space and sediment supply caused by tectonic movement led the delta to prograde or disappear. During the SQ5 period, the clastic rock sedimentary systems underwent a transition into clastic rock and carbonate rock sedimentary systems as a result of rift weakening, broad crustal thermal subsidence, sediment supply reduction and high-salinity lake water. This study provides a typical case for the evolution characteristics of the clastic rock and carbonate rock systems in continental rift basins, identifies changes in the tectonic, sediment supply, and hydrologic characteristics during their mutual transformations, and provides an important reference for hydrocarbon reservoir prediction.

An active molybdenum (polymetallic)-enriching system in foreland basins

Molybdenum (polymetallic)-rich saline brines from the Badain Jaran Desert to the north of the Tibetan Plateau reveal active enrichment of trace metals in the groundwater systems of foreland basins. Molybdenum (polymetallic)-rich brines have salinities of 224–338 g/L and high concentrations of Mo (~3.7 mg/L), Li (~5.8 mg/L), U (~0.65 mg/L), Rb (~2.0 mg/L), Sr (~6.1 mg/L), Mn (~0.62 mg/L), and Ni (~0.52 mg/L). The major ions in the brines are Na+ and Cl−, with small amounts of SO42−. The pH and Eh values are 8.50–8.82 and >200 mV, respectively, with dissolved O contents of >6 mg/L. The δD and δ18O values of these saline brines are −29.2 ‰ to −31.0 ‰ and +0.3 ‰ to +2.8 ‰, respectively, and they exhibit a similar trend to the regional evaporation line, suggesting that the Mo (polymetallic)-rich saline brines originated from evaporation of groundwater in the Badain Jaran Desert. The 3He/4He (R) and R/Ra ratios of the brines are 0.42–2.11 and 0.30–1.51, respectively, and the 38Ar/36Ar and 40Ar/36Ar ratios are 0.194–1.464 and 267.4–360.2, respectively. These results suggest that the Mo-rich saline brines interacted with detrital material in the Badain Jaran Desert and extracted both cosmogenic 3He and radiogenic 4He. We propose that the Mo (polymetallic)-rich saline brines originated from evaporation of groundwater in the Badain Jaran Desert. Regional faults are responsible for the supply of precipitation-derived groundwater to the study area.

Spatio-Temporal Variations in Ecological Quality and Its Response to Topography and Road Network Based on GEE: Taking the Minjiang River Basin as a Case

Urbanization has rapidly increased, leading to a wide range of significant disruptions to the global ecosystem. Road construction has emerged as the primary catalyst for such ecological degradation. As a result, it is imperative to develop efficient technological approaches for quantifying and tracking alterations in the ecological environment. Additionally, it is crucial to delve deeper into the spatial correlation between the quality of the ecosystem and the urban road network. This is of crucial importance in promoting sustainable development within the region. In this study, the research area selected was the Minjiang River Basin (MRB). We made optimal use of the Google Earth Engine (GEE) cloud platform to create a long-term series of remote sensing ecological index (RSEI) data in order to assess the quality of the ecological environment in the area. Additionally, we integrated digital elevation data (DEM) and OpenStreetMap (OSM) road network data to investigate the response mechanisms of RSEI with regard to elevation, slope, and the road network. The findings were as follows: (1) There were two distinct phases observed in the average value of RSEI: a slow-rising phase (2000–2010) with a growth rate of 1.09% and a rapidly rising phase (2010–2020) with a growth rate of 5.36%; the overall 20-year variation range fell between 0.575 and 0.808. (2) During the period of 2000 to 2010, approximately 41.6% of the area exhibited enhanced ecological quality, whereas 17.9% experienced degradation. Subsequently, from 2010 to 2020, the proportion of the region with improved ecological quality rose to 54.0%, while the percentage of degraded areas declined to 3.8%. (3) With increasing elevation and slope, the average value of RSEI initially rose and then declined. Specifically, the regions with the highest ecological quality were found in the areas with elevations ranging from 1200 to 1500 m and slopes ranging from 40 to 50°. In contrast, areas with an elevation below 300 meters or a slope of less than 10° had the poorest ecological quality. (4) The RSEI values exhibited a rapid ascent within the 1200 m buffer along the road network, while beyond this threshold, the increase in RSEI values became more subdued. (5) The bivariate analysis found a negative correlation between road network kernel density estimation (KDE) and RSEI, which grew stronger with larger scales. Spatial distribution patterns primarily comprised High–Low and Low–High clusters, in addition to non-significant clusters. The southeastern region contained concentrated High–Low clusters which covered approximately 10% of the study area, while Low–High clusters accounted for around 20% and were predominantly found in the western region. Analyzing the annual changes from 2000 to 2020, the southeastern region experienced a decrease in the number of High–Low clusters and an increase in the number of High–High clusters, whereas the northwestern region showed a decline in the number of Low–High clusters and an increase in the number of non-significant clusters. This study addresses a research gap by investigating the spatial correlation between road distribution and RSEI, which is vital for comprehending the interplay between human activities and ecosystem services within the basin system.

Forecasting of Flood Flow of Panam River Basin using Adaptive Neuro-Fuzzy Inference System (ANFIS) and ANN with Comparative Study

Flood forecasting is one of the most important issues in the hydrology due to its indispensable contribution in lowering monetary and life losses. In recent years reliability of flood forecasting using various modelling tools has improved to a great extent due to hydrologic modelling, development in expertise and knowledge, and advancement in the collection of data and algorithms for evaluation. The current study presents the use of the Adaptive Neuro Fussy Inference System (ANFIS) in forecasting floods for the Panam River basin system. ANFIS combines neural network algorithms and fuzzy reasoning to map an input space to an output space. This paper includes the development of ANFIS models using various membership function and their comparison for forecasting the inflow rate into the Panam dam, which creates flooding conditions on the downstream side. The different evaluation parameters like Root Mean Square Error (RMSE), Correlation Coefficient (R), Coefficient of Determination (R2) and Discrepancy Ratio (D) are used to evaluate the results of each model. From all the developed ANFIS models, the best ANFIS model is selected, having RMSE as 271.91, R as 0.98, R2 as 0.96, and D as 1.00 for training the model, and RMSE as 2000.74, R as 0.95, R2 as 0.90 and D as 1.12 for validating the model. Artificial Neural Network (ANN) model has also been developed for forecasting flood. In the Neural network there are total 3 types of transfer function in each layer i.e., LOGSIG, TANSIG and PURELIN. All the developed is evaluated with the coefficient of correlation (R) and Mean Squared Error (MSE). In the end, future headings for innovative research work are discussed.

Development of Upper Euphrates Basin hydro-economic model and hydropower generation optimization

Abstract Hydro-economic optimization models are common in hydropower reservoir modeling to aid system operators and planners. In these models, operations are driven by the economic value and constrained by the availability of water. The objective is to either minimize total costs or maximize total benefits. In this study, a hydro-economic optimization model for the integrated reservoir system of the Upper Euphrates Basin, with major tributaries providing water flow to the Euphrates River, is introduced. These model the 10 large-scale reservoirs of the basin with a total installed capacity of 3,255 MW. Water management and hydropower decision-making operations are evaluated with a piecewise linear programming algorithm in monthly time steps using a 45-year historical hydrology between 1971 and 2016. The model aims to maximize hydropower revenue over a long-term time horizon with energy prices varying by month. Reservoir storage and turbine release decisions are optimized for multiple hydropower plants connected in serial or parallel. Hydropower generation, revenue, reservoir storage, capacity ratios and generation reliability results are analyzed. Results show that these hydropower plants generate about 9,481 Gigawatt hour (GWh) of energy with an average turbine capacity use of 36% and obtain a revenue of 620 million $ per year.