Research

18 pages, 5720 KiB

Open AccessArticle

A Study on the Drivers of Remote Sensing Ecological Index of Aksu Oasis from the Perspective of Spatial Differentiation

by Chao Ling, Guangpeng Zhang, Xiaoya Deng, Ayong Jiao, Chaoqun Chen, Fujie Li, Bin Ma, Xiaodong Chen and Hongbo Ling

Water 2022, 14(24), 4052; https://doi.org/10.3390/w14244052 - 12 Dec 2022

Cited by 1 | Viewed by 1663

Abstract

The overexploitation and misuse of natural resources in oaseshave put a significant strain on the ecosystem’s fragility. Therefore, a rigorous study of the ecological environment’s quality is required to assure the sustainability of oasis growth. The GEE platform has the features of timeliness [...] Read more.

The overexploitation and misuse of natural resources in oaseshave put a significant strain on the ecosystem’s fragility. Therefore, a rigorous study of the ecological environment’s quality is required to assure the sustainability of oasis growth. The GEE platform has the features of timeliness and large data cloud processing, which accelerating the development of the remote sensing ecological index. The MODIS data of the research region from 2000 to 2020 were uploaded online to the GEE platform in order to calculate the humidity, greenness, dryness, and heat indices for each year. Principal component analysis was then used to develop the remote sensing ecological index after normalization. In addition, Pearson correlation coefficient, Moran’s I index, geo-detector, and the MK trend test were employed to determine the dependability of the RSEI comprehensive index, analyze the ecological environment status and its change trend in the Aksu River Basin from 2000 to 2020, and investigate the external driving factors of RSEI spatial heterogeneity. (1) The average correlation degree of RSEI is as high as 0.820, and the Moran’s I index is larger than 0.9118; thus, its practicability, dependability, and spatial rationality are enhanced. (2) The natural environment quality of Aksu basin is impacted in two ways by human influences. (1) The adoption of ecological protection measures to support the growth of groundwater reserves in the Aksu basin, increase plant covering, and so improve and enhance the ecological environment’s quality. Following the adoption of ecological protection measures, the average RSEI rose by 12.89%, the ecological quality of the farmland-based region improved considerably, and the quality of the ecological environment was enhanced. (2) Urban growth inhibits environmental progress. The acceleration of urbanization and the large rise in NDBSI have exerted pressure on the development of RSEI, while the growth of cities and towns has decreased the vegetation cover in urban areas and impeded the improvement of ecological environment quality. (3) Both human and environmental causes contribute to the regional variability of RSEI in Aksu Basin. The geographical heterogeneity is mostly caused by temperature and land use, with land use being the most important driver. Strengthening research on the connection between groundwater storage change, land use, vegetation cover, and NDBSI may facilitate the growth of regional green economies. Full article

(This article belongs to the Special Issue Advances in Assessing Water Ecosystem Services for Water Resource Management)

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23 pages, 7223 KiB

Open AccessArticle

Enhancement of Groundwater Recharge from Wadi Al Bih Dam, UAE

by Ahmed Sefelnasr, Abdel Azim Ebraheem, Muhammad Abrar Faiz, Xiaogang Shi, Khaled Alghafli, Faisal Baig, Muhammad Al-Rashed, Dalal Alshamsi, Munaver Basheer Ahamed and Mohsen Sherif

Water 2022, 14(21), 3448; https://doi.org/10.3390/w14213448 - 29 Oct 2022

Cited by 9 | Viewed by 2699

Abstract

Groundwater and harvested rainwater represent the only conventional freshwater resources in the United Arab Emirates (UAE). Groundwater resources in Wadi Al Bih, UAE, are sustainable due to the low exploitation rate for domestic and agricultural purposes. Thus, the groundwater depletion in this area [...] Read more.

Groundwater and harvested rainwater represent the only conventional freshwater resources in the United Arab Emirates (UAE). Groundwater resources in Wadi Al Bih, UAE, are sustainable due to the low exploitation rate for domestic and agricultural purposes. Thus, the groundwater depletion in this area is far less than in other parts of the country. The Wadi Al Bih area is very important for achieving water security in UAE. Therefore, the possible measures of increasing groundwater recharge (e.g., managed aquifer recharge (MAR) methods) are investigated in this paper. The available water resource data were collected, reviewed, validated, and stored in a GIS database. Then, a GIS-based water budget model (WBM) was developed to evaluate the available groundwater resources in Wadi Al Bih and recharge sources. The analyses showed that only 49% of the accumulated rainwater behind the dam is recharging the underlying aquifer. Due to the absence of any direct recharge techniques, the remaining 51% is lost by direct evaporation (15%), and as soil moisture increases in the unsaturated zone (36%), it will subsequently evaporate or percolate depending on the precipitation pattern and air temperature. The results of the WBM indicated that the freshwater resources were decreasing at an alarming rate of approximately thirty-five million cubic meters (MCM) per year until 2019. The groundwater storage and salinity were governed by the rates and patterns of precipitation. For example, the recharge resulting from the two consecutive maximum monthly precipitation events in December 2019 and January 2020 has significantly increased the fresh groundwater reserve and slightly retreated the saline/brackish water toward the shoreline. Moreover, a Mann–Kendall trend analysis was conducted to assess the influence of precipitation, temperature, and evaporation on groundwater recharge. The outcomes suggested that climate variables had a significant effect on groundwater supplies. The mitigation measures include revising groundwater withdrawal rates based on the annual recharge and enhancing recharge using different MAR techniques and dam operation plans. Full article

(This article belongs to the Special Issue Advances in Assessing Water Ecosystem Services for Water Resource Management)

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19 pages, 5021 KiB

Open AccessArticle

Eco-Hydrological Response of Water Conveyance in the Mainstream of the Tarim River, China

by Ayong Jiao, Zikang Wang, Xiaoya Deng, Hongbo Ling and Fulong Chen

Water 2022, 14(17), 2622; https://doi.org/10.3390/w14172622 - 25 Aug 2022

Cited by 5 | Viewed by 1572

Abstract

Desert riparian vegetation forms an ecological corridor in extremely arid environments, and ecological water conveyance is an important measure of vegetation restoration and biodiversity conservation in desert riparian zones. Studying the responses of vegetation to ecological water conveyance and changes in this process [...] Read more.

Desert riparian vegetation forms an ecological corridor in extremely arid environments, and ecological water conveyance is an important measure of vegetation restoration and biodiversity conservation in desert riparian zones. Studying the responses of vegetation to ecological water conveyance and changes in this process in arid desert riparian zones and assessing the comprehensive benefits of ecological water conveyance are highly significant for ecological conservation and restoration in addition to the formulation of water transfer policies. Previous studies mainly used a single indicator to evaluate the ecological restoration of the mainstream Tarim River in Northwest China; thus, systematic and comprehensive assessments based on multiple indicators have not been conducted. In the present study, remote sensing data and field surveys were used to analyze the ecological restoration status of the Tarim River during 2015–2021 in terms of hydrological responses, vegetation responses, and ecological water conveyance benefits. The results showed that groundwater levels and soil moisture in the mainstream area of the Tarim River increased significantly from 2015 to 2021. The amount of groundwater storage also increased. Ecological water conveyance has created good hydrological conditions for groundwater recharge and ecological restoration on both sides of the mainstream area of the Tarim River. Desert forest ecosystems, mainly comprising Populus euphratica and Tamarix ramosissima, have been saved and rejuvenated in water conveyance areas. After ecological water conveyance, the Simpson and Shannon–Wiener indices increased significantly, but the diversity level began to decline and then stabilize with the increase in water conveyance frequency. The overall habitat status improved and the quality of the ecological environment below the Wusiman section of the middle reaches of the Tarim River improved significantly. Full article

(This article belongs to the Special Issue Advances in Assessing Water Ecosystem Services for Water Resource Management)

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19 pages, 4617 KiB

Open AccessFeature PaperArticle

Is There Spatial and Temporal Variability in the Response of Plant Canopy and Trunk Growth to Climate Change in a Typical River Basin of Arid Areas

by Kaiye Yuan, Hailiang Xu and Guangpeng Zhang

Water 2022, 14(10), 1573; https://doi.org/10.3390/w14101573 - 14 May 2022

Cited by 4 | Viewed by 1572

Abstract

The response of plants to climate change has become a topical issue. However, there is no consensus on the synergistic processes of the canopy and trunk growth within different vegetation types, or on the consistency of the response of the canopy and trunk [...] Read more.

The response of plants to climate change has become a topical issue. However, there is no consensus on the synergistic processes of the canopy and trunk growth within different vegetation types, or on the consistency of the response of the canopy and trunk to climate change. This paper is based on Normalized Difference Vegetation Index (NDVI), tree-ring width index (TRW) and climate data from the Irtysh River basin, a sensitive area for climate change in Central Asia. Spatial statistical methods and correlation analysis were used to analyze the spatial and temporal trends of plants and climate, and to reveal the differences in the canopy and trunk response mechanisms to climate within different vegetation types. The results show a warming and humidifying trend between 1982 and 2015 in the study area, and NDVI and TRW increases in different vegetation type zones. On an interannual scale, temperature is the main driver of the canopy growth in alpine areas and precipitation is the main limiting factor for the canopy growth in lower altitude valley and desert areas. The degree of response of the trunk to climatic factors decreases with increasing altitude, and TRW is significantly correlated with mean annual temperature, precipitation and SPEI in desert areas. On a monthly scale, the earlier and longer growing season due to the accumulation of temperature and precipitation in the early spring and late autumn periods contributes to two highly significant trends of increase in the canopy from March to May and August to October. Climatic conditions during the growing season are the main limiting factor for the growth of the trunk, but there is considerable variation in the driving of the trunk in different vegetation type zones. The canopy growth is mainly influenced by climatic factors in the current month, while there is a 1–2-month lag effect in the response of the trunk to climatic factors. In addition, the synergy between the canopy and the trunk is gradually weakened with increasing altitude (correlation coefficient is 0.371 in alpine areas, 0.413 in valley areas and 0.583 in desert areas). These findings help to enrich the understanding of the response mechanisms to climate change in different vegetation type zones and provide a scientific basis for the development of climate change response measures in Central Asia. Full article

(This article belongs to the Special Issue Advances in Assessing Water Ecosystem Services for Water Resource Management)

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24 pages, 4981 KiB

Open AccessArticle

Integrated Growth Model of Typical Crops in China with Regional Parameters

by Fangliang Liu, Yunhe Liu, Lijun Su, Wanghai Tao, Quanjiu Wang and Mingjiang Deng

Water 2022, 14(7), 1139; https://doi.org/10.3390/w14071139 - 01 Apr 2022

Cited by 7 | Viewed by 1903

Abstract

The analysis of common properties of growth for crops is the basis for further understanding crop growth in different regions. We used four typical crops of China, winter wheat, summer maize, rice, and cotton, to build an integrated model suitable for simulating the [...] Read more.

The analysis of common properties of growth for crops is the basis for further understanding crop growth in different regions. We used four typical crops of China, winter wheat, summer maize, rice, and cotton, to build an integrated model suitable for simulating the growth of different crops. The rates and characteristics of crop growth were systematically analysed based on semirelative and fully relative logistic models of crop growth, and a comprehensive, fully relative logistic model for the four crops was established. The spatial distributions of the maximum leaf area index (LAI_max) and maximum dry-matter accumulation (DMA_max) for the four crops were analysed. The semirelative and fully relative growth models exhibited different characteristics of crop growth. The essential characteristics of growth and the characteristics of the crops at each stage of growth were better represented by the fully relative logistic growth model than by the semirelative model. The comprehensive, fully relative logistic model fitted the growth of all four crops well. LAI_max and DMA_max varied greatly amongst the four crops and were strongly regionally distributed. These indicators for the same crop were differentially spatially variable, and the two indicators were not significantly correlated, except for rice. LAI_max and DMA_max in different regions could be obtained using a binary quadratic equation of water consumption and growing degree days for the crops. This study provides a novel method for quantitatively judging the status of crop growth, predicting crop yields, and planning for regional agricultural planting. Full article

(This article belongs to the Special Issue Advances in Assessing Water Ecosystem Services for Water Resource Management)

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18 pages, 9077 KiB

Open AccessArticle

The Nutrient and Heavy Metal Contents in Water of Tidal Creek of the Yellow River Delta, China: Spatial Variations, Pollution Statuses, and Ecological Risks

by Yue Qi, Yilei Zhao, Gang Fu, Junsheng Li, Caiyun Zhao, Xiao Guan and Shuyu Zhu

Water 2022, 14(5), 713; https://doi.org/10.3390/w14050713 - 24 Feb 2022

Cited by 4 | Viewed by 1621

Abstract

In order to understand the spatial distribution, ecological risks, and pollution status of nutrients and heavy metals in the coastal tidal creek water of the Yellow River Delta (YRD), a total of 21 water samples were collected from 7 sample sites. The results [...] Read more.

In order to understand the spatial distribution, ecological risks, and pollution status of nutrients and heavy metals in the coastal tidal creek water of the Yellow River Delta (YRD), a total of 21 water samples were collected from 7 sample sites. The results indicated that along the coastline from northwest to southeast in the YRD, the concentrations of TN, TP, and NH₄⁺-N in the water decreased and then increased; the Cu concentration increased, decreased, and then increased; and the Pb concentration decreased. The average TN/TP mass ratio indicated that the tidal creek water belonged to a potential phosphorus-restricted eutrophication state. The RI result indicated that Cu and Pb in the water were at low ecological risk, while the SSD and RQ results indicated that Cu in the water was at a high ecological risk level and had potential harm to aquatic organisms. Based on the single-factor method, the water quality of the tidal creek inside and outside the Yellow River Delta Nature Reserve belonged to Grade IV. Cu should be controlled to improve the water quality and reduce the ecological risk, especially in the Yellow River Delta Nature Reserve. Full article

(This article belongs to the Special Issue Advances in Assessing Water Ecosystem Services for Water Resource Management)

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11 pages, 3882 KiB

Open AccessFeature PaperArticle

Streamflow Consumption vs. Climate Change in the Evolution of Discharge in the Tarim River Basin, Northwest China

by Fengzhi Shi, Xinhu Li, Yuehui Wang, Xiaofei Ma, Jianting Zhu and Chengyi Zhao

Water 2022, 14(3), 392; https://doi.org/10.3390/w14030392 - 27 Jan 2022

Cited by 2 | Viewed by 2205

Abstract

Quantifying and separating the impacts of hydroclimatic change and human activities on streamflow consumption are crucial issues for the planning, management, and rational allocation of water resources in arid inland river basins. Generalized additive models were used to reveal the interactions between climate, [...] Read more.

Quantifying and separating the impacts of hydroclimatic change and human activities on streamflow consumption are crucial issues for the planning, management, and rational allocation of water resources in arid inland river basins. Generalized additive models were used to reveal the interactions between climate, land-use change, and streamflow consumption in the mainstream Tarim River basin in Northwest China. The results showed that streamflow has decreased, while streamflow consumption has had an increasing trend in the upper reaches and a decreasing trend in the middle and lower reaches during the past 45 years. Land-use change was estimated to contribute 50.1–84.30% (mean of 58.1%) of streamflow consumption, and it was followed by climatic change, which contributed 10.5–28.3% (mean of 21.5%), and inflow runoff, which contributed 11.8–23.6% (mean of 17.7%) from 1970–2015. Land-use change played a dominant role in streamflow consumption in the mainstream Tarim River basin. Cropland expansion and urban area growth were the primary factors causing the decreased streamflow and increased streamflow consumption in the upper reaches. The streamflow consumption in the middle and lower reaches decreased, which was attributed to the decreased inflow. The results are useful for informing policy-making accordingly so that the river can be properly restored, which will benefit the ecosystem services. Full article

(This article belongs to the Special Issue Advances in Assessing Water Ecosystem Services for Water Resource Management)

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18 pages, 5741 KiB

Open AccessArticle

Optimal Alternative for Quantifying Reference Evapotranspiration in Northern Xinjiang

by Ping Jiao and Shun-Jun Hu

Water 2022, 14(1), 1; https://doi.org/10.3390/w14010001 - 21 Dec 2021

Cited by 6 | Viewed by 2289

Abstract

Accurate estimation of reference evapotranspiration is a key step in irrigation and water resources planning. The Penman Monteith (FAO56-PM) formula recommended by FAO56-PM is the standard for calculating the reference evapotranspiration. However, the FAO56-PM model is limited in the observation of meteorological variables, [...] Read more.

Accurate estimation of reference evapotranspiration is a key step in irrigation and water resources planning. The Penman Monteith (FAO56-PM) formula recommended by FAO56-PM is the standard for calculating the reference evapotranspiration. However, the FAO56-PM model is limited in the observation of meteorological variables, so it is necessary to choose an alternative ET₀ model which requires less meteorological data. Based on the daily climate data of eight meteorological stations in northern Xinjiang from 2000 to 2020, seven empirical models (Hargreaves, Berti, Dorji, Dalton, Meyer, WMO, Albrecht) and four optimization algorithms (RF model, LS-SVR model, Bi-LSTM model and GA-BP model) combined with seven different parameters were evaluated comprehensively. The results show that the accurate of the empirical model based on temperature is obviously better than the empirical model based on air mass transport. The annual and multi-year alternative ET₀ models of different input parameter combinations are: LS-SVR1, RF2, LS-SVR3, LS-SVR4, GA-BP5, LS-SVR6, GA-BP7. It can be used as a substitute for the reference evapotranspiration model without relevant meteorological data. Only the LS-SVR6 model and GA-BP7 model are recommended as the best alternative models for northern Xinjiang reference evapotranspiration at daily, monthly and seasonal scales. Full article

(This article belongs to the Special Issue Advances in Assessing Water Ecosystem Services for Water Resource Management)

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18 pages, 2554 KiB

Open AccessArticle

Future Climate Change Impact on the Nyabugogo Catchment Water Balance in Rwanda

by Adeline Umugwaneza, Xi Chen, Tie Liu, Zhengyang Li, Solange Uwamahoro, Richard Mind’je, Edovia Dufatanye Umwali, Romaine Ingabire and Aline Uwineza

Water 2021, 13(24), 3636; https://doi.org/10.3390/w13243636 - 17 Dec 2021

Cited by 4 | Viewed by 4117

Abstract

Droughts and floods are common in tropical regions, including Rwanda, and are likely to be aggravated by climate change. Consequently, assessing the effects of climate change on hydrological systems has become critical. The goal of this study is to analyze the impact of [...] Read more.

Droughts and floods are common in tropical regions, including Rwanda, and are likely to be aggravated by climate change. Consequently, assessing the effects of climate change on hydrological systems has become critical. The goal of this study is to analyze the impact of climate change on the water balance in the Nyabugogo catchment by downscaling 10 global climate models (GCMs) from CMIP6 using the inverse distance weighting (IDW) method. To apply climate change signals under the Shared Socioeconomic Pathways (SSPs) (low and high emission) scenarios, the Soil and Water Assessment Tool (SWAT) model was used. For the baseline scenario, the period 1950–2014 was employed, whereas the periods 2020–2050 and 2050–2100 were used for future scenario analysis. The streamflow was projected to decrease by 7.2 and 3.49% under SSP126 in the 2020–2050 and 2050–2100 periods, respectively; under SSP585, it showed a 3.26% increase in 2020–2050 and a 4.53% decrease in 2050–2100. The average annual surface runoff was projected to decrease by 11.66 (4.40)% under SSP126 in the 2020–2050 (2050–2100) period, while an increase of 3.25% in 2020–2050 and a decline of 5.42% in 2050–2100 were expected under SSP585. Climate change is expected to have an impact on the components of the hydrological cycle (such as streamflow and surface runoff). This situation may, therefore, lead to an increase in water stress, calling for the integrated management of available water resources in order to match the increasing water demand in the study area. This study’s findings could be useful for the establishment of adaptation plans to climate change, managing water resources, and water engineering. Full article

(This article belongs to the Special Issue Advances in Assessing Water Ecosystem Services for Water Resource Management)

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20 pages, 12269 KiB

Open AccessArticle

Temporal and Spatial Changes of Runoff Regime in the Yellow River Basin from 1956 to 2017

by Mingda Yang, Huan Liu, Yuping Han, Qinghui Zeng, Jianhua Wang and Peng Hu

Water 2021, 13(22), 3298; https://doi.org/10.3390/w13223298 - 21 Nov 2021

Cited by 4 | Viewed by 2208

Abstract

The Yellow River is one of the major rivers with severe runoff declines in China, but there are significant differences in runoff changes in the upper and lower reaches of the basin and among different tributaries. However, the characteristic of runoff change and [...] Read more.

The Yellow River is one of the major rivers with severe runoff declines in China, but there are significant differences in runoff changes in the upper and lower reaches of the basin and among different tributaries. However, the characteristic of runoff change and its spatial heterogeneity are not well understood in the whole basin. In this paper, 48 hydrological stations located in the mainstream and major tributaries were selected, and the meteorological and runoff data from 1956 to 2017 were collected. The multi-year and intra-year changes in runoff were analyzed, and then the attribution of climate change and human activity to runoff change was quantified by the climate elasticity coefficients. The results showed that: (1) in the past 60 years, the runoff of the Yellow River showed a serious decrease trend of −8.25 mm/10a. Moreover, most tributaries decreased significantly in runoff with a rate of −1.42 mm/10a to −28.99 mm/10a; (2) for the whole basin, the contribution of climate change and human activity to runoff changes was 13% and 87%, respectively. Moreover, the contribution of the two factors varied considerably in different tributaries. Finally, focusing on different runoff regime and socioeconomic characteristics, this study provided corresponding water resources adaptive management suggestions. Full article

(This article belongs to the Special Issue Advances in Assessing Water Ecosystem Services for Water Resource Management)

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13 pages, 4494 KiB

Open AccessArticle

Spatial Distributions of Nitrogen and Phosphorus in Surface Sediments in Intertidal Flats of the Yellow River Delta, China

by Gang Fu, Yue Qi, Junsheng Li, Caiyun Zhao, Jing He, Yiwen Ma and Jinfang Zhu

Water 2021, 13(20), 2899; https://doi.org/10.3390/w13202899 - 15 Oct 2021

Cited by 4 | Viewed by 1811

Abstract

The spatial distributions of nitrogen (N) and phosphorus (P) in surface sediments are of great significance in studying the ecological process of nutrient cycling in intertidal flats. However, little is known about N and P’s spatial distribution in intertidal flats of the Yellow [...] Read more.

The spatial distributions of nitrogen (N) and phosphorus (P) in surface sediments are of great significance in studying the ecological process of nutrient cycling in intertidal flats. However, little is known about N and P’s spatial distribution in intertidal flats of the Yellow River Delta (YRD). We analyzed the N and P contents in surface sediments and Suaeda glauca density at the low-tidal level to identify the spatial distributions of nutrients and their influencing factors in coastal tidal flat sediments. The results showed that the total nitrogen (TN) and total phosphorus (TP) concentrations in this study were both lower than the background values of China’s shallow sea sediments. The spatial distributions of N and P had significantly spatial heterogeneity, while those of the nutrients at different distances from the low-tidal level to the coastline showed no significant distance effects. The spatial distribution of S. glauca in coastal tidal flats had significant location characteristics and was closely related to the distribution of TN and pH. The TN in non-estuarine intertidal flats was less than that in estuaries; in contrast, the TP was higher in non-estuaries. There are some differences of N and P between estuary and non-estuary areas. Full article

(This article belongs to the Special Issue Advances in Assessing Water Ecosystem Services for Water Resource Management)

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12 pages, 7251 KiB

Open AccessArticle

Estimation of Populuseuphratica Forest Leaf Litterfall and Time Variation of Nutrient in Leaf Litter during Decomposition along the Main Channel of the Tarim River, China

by Yuhai Yang, Honghua Zhou, Zhaoxia Ye and Chenggang Zhu

Water 2021, 13(18), 2514; https://doi.org/10.3390/w13182514 - 14 Sep 2021

Cited by 1 | Viewed by 1947

Abstract

Accurate determination of annual leaf litter amount constitutes the basis of scientific leaf litter nutrient release assessment. In this study, we tried to establish an equation between leaf litter amount and relevant tree characteristics of Populus euphratica (P. euphratica) tree [...] Read more.

Accurate determination of annual leaf litter amount constitutes the basis of scientific leaf litter nutrient release assessment. In this study, we tried to establish an equation between leaf litter amount and relevant tree characteristics of Populus euphratica (P. euphratica) tree on an individual scale, and to find the leaf litter nutrient content variation within 760 d incubation experiment in the main channel of the Tarim River, China. Results showed that there was no proper equation between leaf litter amount and tree height or diameter at breast height. There was great difference in leaf litter amount on an individual scale. The mean annual leaf litter amount per tree was 10.2, 14.83 kg/y obtained by field survey and the equation between annual leaf litter amount and canopy area on an individual scale, respectively. Leaf litter mass changed over incubation time and exhibited three main phases: an initial slow decomposition phase (0–173 d) with mass loss; a rapid mass loss phase (173–290 d); and a second rapid mass loss phase (470–560 d). Overall, carbon (C) and potassium (K) content decreased, and nitrogen (N) and phosphorus (P) content increased in a fluctuating manner over time in the P. euphratica leaf litter. Full article

(This article belongs to the Special Issue Advances in Assessing Water Ecosystem Services for Water Resource Management)

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21 pages, 5467 KiB

Open AccessArticle

Frequency Analysis of Snowmelt Flood Based on GAMLSS Model in Manas River Basin, China

by Chaofei He, Fulong Chen, Aihua Long, Chengyan Luo and Changlu Qiao

Water 2021, 13(15), 2007; https://doi.org/10.3390/w13152007 - 22 Jul 2021

Cited by 4 | Viewed by 2141

Abstract

With the acceleration of human economic activities and dramatic changes in climate, the validity of the stationarity assumption of flood time series frequency analysis has been questioned. In this study, a framework for flood frequency analysis is developed on the basis of a [...] Read more.

With the acceleration of human economic activities and dramatic changes in climate, the validity of the stationarity assumption of flood time series frequency analysis has been questioned. In this study, a framework for flood frequency analysis is developed on the basis of a tool, namely, the Generalized Additive Models for Location, Scale, and Shape (GAMLSS). We introduced this model to construct a non-stationary model with time and climate factor as covariates for the 50-year snowmelt flood time series in the Kenswat Reservoir control basin of the Manas River. The study shows that there are clear non-stationarities in the flood regime, and the characteristic series of snowmelt flood shows an increasing trend with the passing of time. The parameters of the flood distributions are modelled as functions of climate indices (temperature and rainfall). The physical mechanism was incorporated into the study, and the simulation results are similar to the actual flood conditions, which can better describe the dynamic process of snowmelt flood characteristic series. Compared with the design flood results of Kenswat Reservoir approved by the China Renewable Energy Engineering Institute in December 2008, the design value of the GAMLSS non-stationary model considers that the impact of climate factors create a design risk in dry years by underestimating the risk. Full article

(This article belongs to the Special Issue Advances in Assessing Water Ecosystem Services for Water Resource Management)

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