Red River Basin Research Articles

Seasonal variations of sediment load related to all large damming in the Red River system: A 64‐year analysis

AbstractVariations of water discharge and sediment load in the Red River basin have received considerable attention due to its drastic reduction during the past several decades. This paper presents a more specifically investigating of the seasonal variations in water discharge and sediment load from 1958 to 2021, both before and after the impoundment of all large dam‐reservoirs, using daily observations from the Son Tay hydrological gauging station, the outlet of the Red River system and entry to the delta. Sediment loads have decreased progressively since the early 1990s due to sediment yield reduction and dams in the upper basin, with a reduction of about 91% (from 116 × 106 to 11 × 106 t/year) over the 64‐year observation period. Prior to the impoundment of the Hoa Binh dam‐reservoir in 1988, the hydrological processes in the Red River system exhibited seasonal anomalies (clockwise mode on the hysteresis of rating curve), which implies that sediment load is highly proportional to water discharge and precipitation. The hysteresis loops between mean monthly water discharge and suspended sediment concentration after 1988 were altered by tributary dam‐reservoirs and a phenomenon known as ‘temporal monsoon moving’, which shifted the rating curve from clockwise to counterclockwise mode. Our long‐term analysis indicates that approximately 57.5% and 79% of sediments were trapped during the periods 1989–2008 (after Hoa Binh dam‐reservoir impoundment) and 2009–2021 (a series of new dam‐reservoirs went into operation), respectively, primarily during the high‐discharge months (June–October). Additionally, we concluded that the contribution of climate components (e.g., rainfall) to the dramatic decline in sediment load of the Red River system was less than the human impact.

Impacts of climatic variability on surface water area observed by remotely sensed imageries in the Red River Basin

Recent wetting in the Northern Great Plain (NGP) exerted strong influences on lakes and wetlands. However, the influence of recent increase in precipitation on spatiotemporal variation of surface water area is poorly understood in the Red River Basin (RRB, northern United States and southern Canada). Here, we used a high-resolution global surface water dataset to understand spatiotemporal dynamics of the annual, total, permanent, and seasonal water extent in RRB. Monthly surface water area is investigated to detect the change in seasonal surface water extent. We found four distinct phases of variation in surface water: Phase 1 (1990–2001, wetting); Phase 2 (2002- 2005, dry); Phase 3 (2006–2013, recent wetting); and Phase 4 (2014–2019, recent drying). A bare land to a permanent and seasonal water area switch is observed during Phase 1, while the other phases have experienced relatively little fluctuation. Findings have implications for nutrient concentration assessment in lakes and wetlands.

Exploring “big picture” scenarios for resilience in social–ecological systems: transdisciplinary cross-impact balances modeling in the Red River Basin

Climate change is increasing the frequency and the severity of extreme events in river basins around the world. Efforts to build resilience to these impacts are complicated by the social–ecological interactions, cross-scale feedbacks, and diverse actor interests that influence the dynamics of change in social–ecological systems (SESs). In this study, we aimed to explore big-picture scenarios of a river basin under climate change by characterizing future change as emergent from interactions between diverse efforts to build resilience and a complex, cross-scale SES. To do so, we facilitated a transdisciplinary scenario modeling process structured by the cross-impact balances (CIB) method, a semi-quantitative method that applies systems theory to generate internally consistent narrative scenarios from a network of interacting drivers of change. Thus, we also aimed to explore the potential for the CIB method to surface diverse perspectives and drivers of change in SESs. We situated this process in the Red River Basin, a transboundary basin shared by the United States and Canada where significant natural climatic variability is worsened by climate change. The process generated 15 interacting drivers ranging from agricultural markets to ecological integrity, generating eight consistent scenarios that are robust to model uncertainty. The scenario analysis and the debrief workshop reveal important insights, including the transformative changes required to achieve desirable outcomes and the cornerstone role of Indigenous water rights. In sum, our analysis surfaced significant complexities surrounding efforts to build resilience and affirmed the potential for the CIB method to generate unique insights about the trajectory of SESs.

Operating Multi-Purpose Reservoirs in the Red River Basin: Hydropower Benefit Optimization in Conditions Ensuring Enough Water for Downstream Irrigation

Operational management of multiple reservoirs and hydropower plants in the Red River Basin (RRB) in Vietnam was investigated for optimal benefit of hydropower generation and to ensure the water supply for agricultural and social–economic development downstream during the dry season. This research will investigate the operation of three hydropower reservoirs, including Hoa Binh, Thac Ba, and Tuyen Quang reservoirs. Those reservoirs are managed under the operating Decision No. 740 of the Prime Minister in 2019, which stipulates the dry season and water - enhanced discharge period to supply water for agriculture and ensures that the minimum water level in Hanoi is above 2.2 m, which may lead to lack of water for hydropower plants. To do this, I used the optimization approach to determine the optimal water discharge scenario in these three reservoirs during the enhanced discharge period (irrigation water supply). Based on the optimal scenario, I calculated the amount of saved water which is then compared with the standard discharge scenario under Decision No. 740. This study also found that there is an increasing economic benefit from saved water and hydropower generation during peak hours (after the winter–spring crop). Addtionally, the results demonstrated that the economic value added by the power generation of three reservoirs is about 401.7 billion VND. If compared with using thermal power plants, it saves 858.0 billion VND.

Alp-valley and elevation effects on the reference evapotranspiration and the dominant climate controls in Red River Basin, China: Insights from geographical differentiation

Complicated topography can drastically affect the geographical distribution of evaporation, runoff production, water cycle, and water security guarantee. However, whether the elevation and Alp-valley have differentiated effects on basin evaporation and handle the change with constant variables is still being determined. This manuscript calculates reference evapotranspiration (ET0) of the Red River Basin with a typical Alp-valley and elevation gradient from 1960 to 2021. Then at the scales of the whole basin, both sides of the main Alp (western of Ailao mountain (WAL) and eastern of Ailao mountain (EAL)), the mainstream valley (Yuanjiang valley (YJV)), the spatial–temporal distribution pattern of ET0 and its sensitivity of climate variables are depicted from the insights of barrier-corridor and elevation effects. The results indicate that ET0 grows at a rate of 27.77 mm per decade throughout the Red River Basin, China (RRBC), gradually declines from northwest to southeast, and increases with increasing elevation. The barrier effect of the Ailao Mountains within the RRBC alters the elevation distribution pattern of ET0 on both sides of the mountain. In contrast, the corridor effect along the YJV causes the ET0 increases with the depth of the valley. Accordingly, the aridity index increases with rising elevation resulting in drier climatic conditions in the north of the RRBC, and suffers a significant influence from Alp-valley topography resulting in wet WAL, dry EAL and drier YJV. The topography plays an impact on ET0 through the climatic control variables. Solar radiation (Rs) has the highest impact on ET0, followed in descending order by relative humidity (RH), air temperature (T) and wind speed (U). With the elevation increases, Rs and T reduce the effect on ET0, whereas RH increases its effect. Also, the barrier effect changed the dominant factors: Rs and RH control the ET0 on WAL and EAL, respectively, while the corridor effect enhances the role of T and U. Moreover, the schematic diagram of the ET0’s change with elevation gradient and Alp-valley, and its climate controls is deduced. This research can help us comprehend the spatial differentiation of ET0 in complicated topographical areas, as well as uncover its dynamic mechanisms under elevation and Alp-valley effects.

Water tenure analysis: A case study in Nui Coc irrigation system in the Red River Basin, Vietnam

AbstractVietnam is considered to have a sound legal system for water resources management, but the enforcement of these systems remains limited. This weakness and its causes were reported in various studies on institutional arrangements. However, clear relationships among stakeholders with respect to water resources, or water tenure, and levels of implementation of water tenure governance that are related to these limitations remain undocumented. Using a new approach on water tenure analysis to identify issues and conflicts related to water tenure arrangements in a pilot area in Vietnam is the aim of this study. Most of the types of possible formal (8) and informal (7) water tenure arrangements were identified in the pilot area. The analysis of water tenure governance covering 14 aspects and the assessment of water tenure security were conducted in the study area. The study results illustrate the need to improve the implementation of law enforcement and to strengthen the process of water tenure governance. Based on the analysis results, several relevant solutions are recommended including review and update of legal framework and strengthening the enforcement of current legal regulations in Vietnam.

Variation in Prairie Chub hatch relationships across wet and dry years in the upper Red River basin

AbstractObjectiveThe Prairie Chub Macrhybopsis australis is a poorly studied minnow species endemic to the upper Red River basin and is of both state and federal conservation interest due to uncertainty about its life history and potential listing status. The upper Red River basin of Oklahoma and Texas is a harsh environment where drought and extreme flow events are exacerbated by human alterations. As an assumed pelagic‐broadcast‐spawning minnow, the Prairie Chub is capable of a protracted spawning season and larval fish survival is assumed to be linked to discharge and streamflow variability.MethodsWe systematically collected 2,017 age‐0 Prairie Chub from seven sites (North Fork Red River, Salt Fork Red River, Pease River, Red River, Prairie Dog Town Fork Red River, North Wichita River, and South Wichita River) with variable flow patterns during April–September 2019 and May–August 2020. We used otolith age estimates and back calculations to determine successful spawning dates. We used a hurdle model framework to examine relationships between hatch probability and hatch frequency.ResultHatch probability had a negative relationship with calendar day and declined as calendar day increased. Hatch counts peaked in late June and early July and declined thereafter in 2019 but showed no discernible peak during the spawning season in 2020. Hatch probability during the spawning season increased with relative flow and air temperature. Increased hatch counts were also positively related to discharge variability (CV) for the 10 d prior to hatch dates.ConclusionOur findings indicated that successful hatches had considerable spatial and temporal variability, with some sites contributing minimally to the population during some years. Spatial and temporal variability of hatch probability and hatch frequencies pose a variety of considerations for future conservation and management efforts, particularly given the pending federal listing status of the species.

Prehistoric pathways to Anthropocene adaptation: Evidence from the Red River Delta, Vietnam.

Over the past twenty years, government advisory bodies have placed increasing emphasis on the need for adaptive measures in response to the effects of human-induced climate change. Integrated Assessment Models (IAMs), which incorporate macroeconomic and climate variables, feature prominently in advisory content, though they rarely draw on data from outside strictly constrained hypothetical systems. This has led to assertions that they are not well-suited to approximate complex systemic human-environment processes. Modular, interdisciplinary approaches have offered a way to address this shortcoming; however, beyond climate records, prehistoric data continue to be under-utilised in developing such models. In this paper we highlight the contribution that archaeology and palaeoecology can make to the development of the next generation IAMs that are expected to enhance provision for more local and pro-active adaptations to future climate change. We present data from one of Southeast Asia's most heavily developed river deltas: the Red River (Song Hong) Delta, in Vietnam and localised analysis from the Tràng An Landscape Complex World Heritage Site, on the delta's southern margin. Comparison is made between Shared Socio-economic Pathways (SSP) 5-8.5 and SSP2-4.5 emission projection models and the Mid-Holocene inundation of the Red River Basin. We highlight the value to taking a scientific long view of coastal evolution through an illustrative set of eight research foci where palaeo-data can bring new and localised empirical data to bear on future risk management planning. We proceed to demonstrate the applicability of palaeoenvironmental, zooarchaeological and historical evidence to management and the development of sustainable conservation strategies using Tràng An as a case study. In so doing, we further highlight the importance of knowledge exchange between scientific, corporate, non-governmental, local, and state stakeholders to achieve tangible results on the ground.

Factors influencing the spatial and temporal variations of surface runoff coefficient in the Red River basin of Vietnam

Factors influencing the spatial and temporal variations of surface runoff coefficient in the Red River basin of Vietnam

The geochemical gas field in surface sediments in the Southwest sub-basin of East Vietnam Sea: distribution, origin, and comparative features with other regions of Western East Vietnam Sea

We analyzed 39 gas samples, including carbon dioxide, hydrocarbon gases C1–C4, hydrogen, and helium, in surface sediment from 19 gravity cores collected from the SW sub-basin of the East Vietnam Sea (EVS) using the headspace and vacuum degassing methods. Based on the result, we discussed the distribution and origin of gases in the southwest sub-basin EVS surface sediments. The sediments are mostly clay and silty clay containing methane ranging from 0.5–440 ppm. The anomalous concentrations of methane, helium, and hydrogen occur along the continental slope in the Nam Con Son basin of Southwest EVS. Methane is the dominant gas compared to other detected hydrocarbon gases, including ethylene, propane, and butane. Based on comparative results, the background methane concentrations in surface sediments decrease from South to North, from the southwestern sub-basin of the East Vietnam Sea to the Phu Khanh and the Red river basins. We propose the presence of a large-scale degassing zone of hydrocarbon gases and discuss the gases’ origin in surface sediments based on hydrocarbon gas ratios, carbon isotope compositions of carbon dioxide and methane, and the relationship between geochemical characteristics of surface sediments and fault system, and surface sediment gases.

Applicability of macrobenthos indexes in health assessment upstream of a large river: A case study in the Babian River of the Red River Basin, China

Biological assessment is an important component of river health assessments. With the thorough growth of river health assessment in China, the scientific verification and screening of straightforward, easily quantifiable, and widely used bio-assessment indexes has emerged as a significant scientific challenge that needs to be resolved immediately in river health assessment. In 2019, 28 sections of the Babian River were examined for water quality, macrobenthos, status of the riparian zone and societal value. Based on the presence of macrobenthos in river health assessments, the applicability of 17 indexes was analyzed. The indexes that could differentiate between reference sites and impaired sites were B-IBI, S2, S3, and BMWP, which had good correlation with environmental factors. Although there was no significant link with riparian conditions, B-IBI, S2, S3, and BMWP had strong negative correlations with total ammoniacal nitrogen, total nitrogen, and total phosphorus but S2, S3, and BMWP are effective alternatives for B-IBI in river health assessment since their results were comparable to those of B-IBI, which covered all the assessment grades. Moreover, when constructing and selecting a bio-assessment index, more attention should be paid to the role of dominant and rare species, as well as the appropriate condition of indexes. In addition, riparian condition is a necessary aspect of river health assessment, but it is challenging to reflect the influence of land components on river health because of the small scale of riparian investigation. Therefore, it is necessary to introduce basin-scale indexes to optimize river health assessment systems. By doing this, watershed system management and overall governance will be supported more effectively.

Three new species of Homatula (Teleostei: Nemacheilidae) from Yunnan, China, with comments on habitat conservation.

Based on the morphological comparisons and molecular results, three new species of Homatula, i.e., H. geminusclathratus sp. nov., H. microcephala sp. nov., and H. longibarbatus sp. nov., have been described and named from the Lancang-jiang (the upper Mekong River) and the Chuan-he (the upper Black River, a tributary of the Red River) basins. The loaches of Homatula from the Lancang-jiang and the Chuan-he can be distinguished via morphology, genetics, and geographic distribution. All of the 10 recorded species distributed in the Nu-jiang (the upper Salween River), the Lancang-jiang, and the upper Black River share the following combination of character states: whole body, except head, densely scaled; lateral line complete; and a short adipose crest along the dorsal midline of the caudal peduncle, anteriorly not reaching vertically through the anal-fin origin. Species with these characters are called the densely-scaled group of Homatula. The three newly described species belong to the densely-scaled group of Homatula. Based on molecular phylogenetics, these Homatula species form a monophyletic group that can be divided into two clades, the densely-scaled group and the non-densely-scaled group. The densely-scaled group of Homatula includes 13 species occurring between the Nu-jiang and the upper Black River. The non-densely-scaled group is non-monophyletic and includes 14 species that are distributed in the Red, Pearl, Yangtze, and Yellow River basins. Species of the non-densely-scaled group are clustered into four sub-clades that are constrained to the four river basins. Homatula exclusively inhabits mountain streams with rapid or gentle currents, vauclusian springs, underground rivers connected to streams, and ditches near villages and farmland. No specimens of Homatula were collected from the main streams of Lixian-jiang, Lancang-jiang, and Nu-jiang as well as their large tributaries. Small environmental changes in the habitat of Homatula, such as water pollution or extensive human use, can lead to species/population extinction. Effective conservation of rare and endemic fishes, like loaches of Homatula, entails systematic observations and more targeted protection.

Impacts of the policy on exemption of irrigation service fee on irrigation performance, a case study in the Red River Basin, Vietnam

AbstractThe policy on irrigation service fee had been adopted in irrigated agriculture in Vietnam for decades but has changed to exemption since 2008. This study surveyed irrigation systems in the Red River basin and found that the ratio of irrigated area to cultivation command area of irrigation system increased from 85% to 91% for a period 2008–2014 thanks to increased maintenance fund for upgrading irrigation systems. Using the Difference in Difference method, the study assessed impact of the policy on on‐farm irrigation performance, agricultural productivity, and household economy at sites across the 44,600 ha of the Cau Son Irrigation System. The analysis found that the exemption policy had a negative and significant impact (p < 0.01) on on‐farm irrigation performance measured by flexibility, reliability, and equity indicators. We found the exemption caused no significant impact on agriculture productivity, cultivation labor, or rice yield in the study area. While net cultivation income of the sample households increased, total income and gross cultivation income of these households were not affected as irrigation service fee accounts for only 1–2% of the total annual household incomes. For improved irrigation performance, it is recommended to revise the current exemption policy and follow a cost recovery approach.

Fish fauna of the Red River, Southeast Asia: Indictors and implications for planning fish species preserves

The composition of fish fauna in the Red River basin was analyzed based on 288 fish species belonging to 138 genera, 53 families (subfamilies), and 14 orders, using the Traditional Fish Fauna Analysis (TFFA) and the Value of Fish Fauna Presence (VFFP) methods. The TFFA and VFFP methods allow for a ranking of the taxa according to commonality and uniqueness of the taxa to the river basin; however, both methods provide different, complimentary results. Based on the results from the TFFA method, 15 families (subfamilies), including 85 genera and 219 species, were identified as the main fish taxa in the Red River basin. Based on the results of the VFFP method, 17 families (subfamilies), including 89 species and 52 genera, were highlighted as representative families (subfamilies) and genera in the Red River basin. Overall, Cypriniformes was the most abundant order, followed by Siluriformes and Gobiiformes. Although the Red River basin is geographically situated in Southeast Asia, it had obvious characteristics of East Asian fish fauna rather than Southeast Asian fish fauna. Therefore, the Red River fish fauna can be considered the boundary between the fish fauna of Southeast Asia and East Asia. This paper further detailed the indexes and calculations of the TFFA and VFFP methods. The authors proposed using the results of the TFFA and VFFP methods as indicators for planning fish preserves as well as discussed the specific methods related to using these indicators to plan and establish fish preserves.

Influence of climate, topography, and soil type on soil extractable phosphorus in croplands of northern glacial-derived landscapes.

Delineating the relative solubility of soil phosphorus (P) in agricultural landscapes is essential to predicting potential P mobilization in the landscape and can improve nutrient management strategies. This study describes spatial patterns of soil extractable P (easily, moderately, and poorly soluble P) in agricultural landscapes of the Red River basin and the southern Great Lakes region. Surface soils (0-30cm) and select deeper cores (0-90cm) were collected from 10 cropped fields ranging in terrain (near-level to hummocky), soil texture (clay to loam), composition (calcareous to noncalcareous), and climate across these differing glacial landscapes. Poorly soluble P dominated (up to 91%) total extractable P in the surface soils at eight sites. No differences in the relative solubilities of soil extractable P with microtopography were apparent in landscapes without defined surface depressions. In contrast, in landscapes with pronounced surface depressions, increased easily soluble P (Sol-P), and decreased soil P sorption capacity were found in soil in wetter, low-slope zones relative to drier upslope locations. The Sol-P pool was most important to soil P retention (up to 28%) within the surface depressions of the Red River basin and at sites with low-carbonate soils in the southern Lake Erie watershed (up to 28%), representing areas at elevated risk of soil P remobilization. This study demonstrates interrelationships among soil extractable P pools, soil development, and soil moisture regimes in agricultural glacial landscapes and provides insight into identifying potential areas for soil P remobilization and associated P availability to crops and runoff.

Reconstruction of Chemical Weathering Intensity and Asian Summer Monsoon Evolution in the Red River Basin Over the Past 36 kyr

AbstractThe Red River is located at the intersection of the Indian and East Asian monsoons. Understanding the evolution history of the monsoon in the Red River basin helps to comprehend the evolution of Asian Summer Monsoon. Herein, we present the high‐resolution major elements and Sr‐Nd isotopic ratios of the terrigenous sediment component for a well‐dated core retrieved from the northern South China Sea slope, aiming to identify the sediment provenance and reconstruct the silicate chemical weathering intensity since the past 36 kyr. The Red River was confirmed as the major sediment source through Sr‐Nd isotopic ratios. The silicate chemical weathering was affected by the rapid changes of sea level and monsoon, and thus it is difficult to indicate the regional paleoenvironment by the weathering degree. The principal component 1 composed of TFe2O3, Al2O3, K2O and MgO was shown to represent the fine‐grained sediment discharge, and employed as a proxy for the summer monsoon rainfall. Global cooling events/stages were identified through the proxies, including the Last Glacial Maximum, Heinrich events, Younger Dryas, and 8.2 ka, as well as the enhanced summer monsoon stages, including the Bølling/Allerød and early Holocene. Based on the comparison with the neighboring paleoclimate indicators, the region summer monsoon of the Red River basin was found to be governed by the Indian summer monsoon, and the summer insolation at low latitudes might be the primary forcing force on the orbital scale.

Investigating the sources and dynamics of naturally occurring radioactive material (NORM) in the Red Deer River, Alberta, Canada.

Distinguishing between natural and anthropogenic controls on the proportions of naturally occurring radioactive materials (NORMs) in the environment is important for water resource management. In this study, the dynamics of uranium (U) and thorium (Th), two of the most prominent NORM elements, were investigated in the Red Deer River basin using monitoring data collected from 2015 to 2018. More than twofold increases in median proportions of total U (from 0.73 to 1.53µg/L) and Th (from 0.008 to 0.104µg/L) were observed for sites located downstream of the Steveville badlands, an area of highly erodible bedrock that a ~ 300km section of the river flows through. Input is highly variable, coinciding mainly with increases in total suspended solids during intense rainstorms in the late summer. In-depth examination of monitoring data through factor analysis, multiple linear regression, mass balance calculations, and land use analysis highlights the importance of erosion and subsequent particle transport along river banks in the badlands area on the distribution of total U and Th, while also revealing that groundwater-surface water interaction affects proportions of dissolved U throughout the river. No significant influence from industry or land use on U and Th export was found, and proportions of U and Th in water and suspended sediment are within the natural ranges expected for surface waters and sediments/soils. Methodology employed in this study provides a basic framework for analysis of environmental monitoring datasets, which can be employed in the absence of radiochemical data to study the fate, transport, and sources of NORMs.

An evaluation of the performance of IMERG hourly precipitation estimates in a geographical sub-region with complex terrain and climate conditions: a case study in the upper Red River Basin

ABSTRACT This study comprehensively evaluates four satellite precipitation estimates (SPE) of the version 6 (V06) of Integrated Multi-satellite Retrievals for Global Precipitation Measurement Mission (IMERG) at hourly scale in the upper Red River Basin (URRB), located in Yunnan, by applying 12 rain gauges during the rainy season (May to October) from 2019 to 2020. Four SPE includes IMERG-E, IMERG-L, IMERG-FU and IMERG-FC, with IMERG-FC is calibrated by the Global Precipitation Climatology Centre (GPCC) gauge. Due to the complex terrain of the URRB, we divide the URRB into three subregions. The evaluation considers precipitation detection capability (POD, FAR and CSI), correlation (CC), error situation (RMSE and RBIAS) and the quantitative analysis index (CPI). The results show that (1) among these SPE, IMERG-FC always has higher POD and FAR, better correlation and larger RBIAS. (2) In the URRB, the results produced by all SPE are overestimates compared to ground-based observations (GBO). And, the detection capability of IMERG is better in the low precipitation threshold but worsens with the increasing precipitation thresholds. (3) IMERG shows worse performance in the dry-hot valley than in the other two areas. (4) The performance of IMERG-L is better than IMERG-FC and other SPE in the URRB.

Integrating local and global projections for the generation of water demand scenarios in the Red River Basin, Vietnam

Planning and management of water supply systems require projections to account for future changes in climate and society. Global and local future scenarios are generated by using models at different spatial scales. The choice of the scale affects if and how the regional socio-economic structure as well as global and local development strategies are considered, and which uncertainties are treated explicitly. This study explores the integration of global and local scale scenarios. Our approach is demonstrated on the Red River basin, Vietnam, where a set of plausible water demands scenarios is generated for 2050. Results show that water demand will increase by 28-58% compared to 2010 when considering all scenarios of climate and socio-economic changes. The ensemble of integrated demands shows a strong dependence of water demand upon the climate-socio-economic state, which allow a better characterization of the future water supply sector dynamics than those obtained by global or local projections only.

Multi-Source Hydrological Data Products to Monitor High Asian River Basins and Regional Water Security

This project explored the integrated use of satellite, ground observations and hydrological distributed models to support water resources assessment and monitoring in High Mountain Asia (HMA). Hydrological data products were generated taking advantage of the synergies of European and Chinese data assets and space-borne observation systems. Energy-budget-based glacier mass balance and hydrological models driven by satellite observations were developed. These models can be applied to describe glacier-melt contribution to river flow. Satellite hydrological data products were used for forcing, calibration, validation and data assimilation in distributed river basin models. A pilot study was carried out on the Red River basin. Multiple hydrological data products were generated using the data collected by Chinese satellites. A new Evapo-Transpiration (ET) dataset from 2000 to 2018 was generated, including plant transpiration, soil evaporation, rainfall interception loss, snow/ice sublimation and open water evaporation. Higher resolution data were used to characterize glaciers and their response to environmental forcing. These studies focused on the Parlung Zangbo Basin, where glacier facies were mapped with GaoFeng (GF), Sentinal-2/Multi-Spectral Imager (S2/MSI) and Landsat8/Operational Land Imager (L8/OLI) data. The geodetic mass balance was estimated between 2000 and 2017 with Zi-Yuan (ZY)-3 Stereo Images and the SRTM DEM. Surface velocity was studied with Landsat5/Thematic Mapper (L5/TM), L8/OLI and S2/MSI data over the period 2013–2019. An updated method was developed to improve the retrieval of glacier albedo by correcting glacier reflectance for anisotropy, and a new dataset on glacier albedo was generated for the period 2001–2020. A detailed glacier energy and mass balance model was developed with the support of field experiments at the Parlung No. 4 Glacier and the 24 K Glacier, both in the Tibetan Plateau. Besides meteorological measurements, the field experiments included glaciological and hydrological measurements. The energy balance model was formulated in terms of enthalpy for easier treatment of water phase transitions. The model was applied to assess the spatial variability in glacier melt. In the Parlung No. 4 Glacier, the accumulated glacier melt was between 1.5 and 2.5 m w.e. in the accumulation zone and between 4.5 and 6.0 m w.e. in the ablation zone, reaching 6.5 m w.e. at the terminus. The seasonality in the glacier mass balance was observed by combining intensive field campaigns with continuous automatic observations. The linkage of the glacier and snowpack mass balance with water resources in a river basin was analyzed in the Chiese (Italy) and Heihe (China) basins by developing and applying integrated hydrological models using satellite retrievals in multiple ways. The model FEST-WEB was calibrated using retrievals of Land Surface Temperature (LST) to map soil hydrological properties. A watershed model was developed by coupling ecohydrological and socioeconomic systems. Integrated modeling is supported by an updated and parallelized data assimilation system. The latter exploits retrievals of brightness temperature (Advanced Microwave Scanning Radiometer, AMSR), LST (Moderate Resolution Imaging Spectroradiometer, MODIS), precipitation (Tropical Rainfall Measuring Mission (TRMM) and FengYun (FY)-2D) and in-situ measurements. In the case study on the Red River Basin, a new algorithm has been applied to disaggregate the SMOS (Soil Moisture and Ocean Salinity) soil moisture retrievals by making use of the correlation between evaporative fraction and soil moisture.