Downstream Resources Research Articles

Wildfire and Its Impact on the Ecosystem in Guizhou Province

ABSTRACTIn February 2024, a total of 221 recorded excess wildfires occurred throughout Guizhou Province. The atypical weather conditions attributed to climate change, seasonal drought during the non‐monsoon period, and human activities associated with the Spring Festival are identified as the primary factors contributing to this period of extensive wildfires. To facilitate a comprehensive assessment of the local ecosystem, analyses were conducted on precipitation, temperature, air quality index records, and water quality monitoring of downstream lakes and rivers. The early onset of the rainy season in April exacerbated soil erosion in Guizhou Province, where 81% of the terrain is mountainous. The repercussions of the excess wildfires on the downstream surface water ecosystem may persist for several months. The findings revealed significant differences in biomass accumulation and response times between rivers and lakes. A more thorough understanding of the impacts of wildfires on water and soil is essential for the formulation of effective recovery policies aimed at safeguarding downstream water resources.

Impact of changes in climate and glacier configurations on runoff from the Langtang River basin, Nepal

Abstract. Climate change is rapidly altering Himalayan glaciers, jeopardizing downstream water resources. This study investigates the impact of changing air temperatures, precipitation, and glacier configurations on streamflow in the Langtang River basin, a vital Himalayan basin. Using a process-based glacio-hydrological model driven by bias-corrected reanalysis data, we simulate streamflow under various scenarios. Results reveal that, while current glacier conditions show increased runoff with higher temperatures and precipitation, future deglaciation scenarios project a decrease in total streamflow, highlighting the complex interplay between climate and glacier dynamics in basin hydrology. These findings emphasize the need for adaptation strategies to ensure water security in the face of evolving Himalayan hydrology.

How to manage regime shifts: insights from a dryland social–ecological system

ABSTRACT Effective water resource management in the Zayandeh-Rud River Basin, a critical region in the Middle East, requires understanding system dynamics and anticipating regime shifts. This study uses system dynamics to model water consumption changes in the basin, analysing various scenarios (10% to 30% increase/decrease) in agricultural, urban, and industrial sectors. Results show that increased consumption harms water systems, while reductions, especially a 30% decrease, stabilize systems and improve water quality. Upstream reductions benefit downstream resources, highlighting the importance of integrated management. Proactive strategies can mitigate adverse impacts, ensuring a sustainable water future for the region’s inhabitants.

Using the R Package, nsink, to assess landscape N removal in coastal catchments.

Excess nitrogen (N) loading to coastal ecosystems impairs estuarine water quality. Land management decisions made within estuarine watersheds have a direct impact on downstream N delivery. Natural features within watersheds can act as landscape sinks for N, such as wetlands, streams and ponds that transform dissolved N into gaseous N, effectively removing it from the aquatic system. Identifying and evaluating these landscape sinks and their spatial relationship to N sources can help managers understand the effects of alternative decisions on downstream resources. The N-Sink approach uses widely available GIS data to identify landscape sinks within HUC-12 (or larger) catchments, estimate their N removal potential and map the effect of those sinks on N movement through the catchment. Static maps are produced to visualize N removal efficiency, transport and delivery, the latter in the form of an index. The R package nsink was developed to facilitate data acquisition, processing and visualization. nsink creates static maps for a specific HUC-12, or users can visit the University of Connecticut website to explore previously mapped areas. Users can investigate specific flowpaths interactively by clicking on any location within the catchment. A flowpath is generated with a table describing N removal along each segment. We describe the motivation behind developing nsink, discuss implementation in R, and present two use case examples. nsink is available from https://github.com/USEPA/nsink. N-Sink is a decision support tool created for local decision-makers and NGOs to facilitate better understanding of the relationship between land use and downstream N delivery. Local decision-makers that have prioritized N mitigation in their long-term planning can use nsink to better understand the potential impact of proposed development projects, zoning variances, and land acquisition or restoration. nsink also allows resource economists to investigate the tradeoffs among different, often costly, N reduction strategies.

Real-world evidence study on the impact of SPECT MPI, PET MPI, cCTA and stress echocardiography on downstream healthcare utilisation in patients with coronary artery disease in the US.

Coronary artery disease (CAD) is associated with a large clinical and economic burden. However, consensus on the optimal approach to CAD diagnosis is lacking. This study sought to compare downstream healthcare resource utilisation following different cardiac imaging modalities, to inform test selection for CAD diagnosis. Claims and electronic health records data from the Decision Resources Group Real-World Evidence US Data Repository were analysed for 2.5 million US patients who underwent single-photon emission computed tomography myocardial perfusion imaging (SPECT MPI), positron emission tomography myocardial perfusion imaging (PET MPI), coronary computed tomography angiography (cCTA), or stress echocardiography between January 2016 and March 2018. Patients were stratified into nine cohorts based on suspected or existing CAD diagnosis, pre-test risk, and prior events or interventions. Downstream healthcare utilisation, including additional diagnostic imaging, coronary angiography, and cardiac-related health system encounters, was compared by cohort and index imaging modality. Among patients with suspected CAD diagnosed within 3 months of the index test, PET MPI was associated with lower downstream utilisation; 25-37% of patients who underwent PET MPI required additional downstream healthcare resources compared with 40-49% of patients who received SPECT MPI, 35-41% of patients who underwent cCTA, and 44-47% of patients who received stress echocardiography. Patients who underwent PET MPI experienced fewer acute cardiac events (5.3-9.4%) and generally had lower rates of healthcare encounters (0.8-4.1%) and invasive coronary angiography (ICA, 15.4-24.2%) than those who underwent other modalities. SPECT MPI was associated with more downstream ICA (31.3-38.2%) and a higher rate of cardiac events (9.5-13.2%) compared with PET MPI (5.3-9.4%) and cCTA (6.9-9.9%). Across all cohorts, additional diagnostic imaging was 1.6 to 4.7 times more frequent with cCTA compared with PET MPI. Choice of imaging modality for CAD diagnosis impacts downstream healthcare utilisation. PET MPI was associated with lower utilisation across multiple metrics compared with other imaging modalities studied.

Effect of gold mine activity on water quality and human health

ABSTRACT This study aimed to investigate the levels of heavy metals in surface and groundwater sources within the vicinity of a gold mine in Iran, as well as to evaluate the associated health and carcinogenic risks. A total of 45 water samples were collected from the mine effluent, the downstream of a river receiving the effluent of the mine, and downstream water resources. Subsequent to laboratory digestion of the samples, arsenic levels were determined using atomic fluorescence spectrophotometry, while other heavy metals were quantified using inductively coupled plasma mass spectrometry (ICP-MS). Data analysis was conducted utilizing IBM SPSS software (Version 22). The health risks and carcinogenic potentials associated with arsenic, lead, cadmium, chromium, cobalt, manganese, mercury, nickel, copper, and zinc were assessed for both pediatric and adult populations. The findings revealed that, in most instances, heavy metal concentrations exceeded the recommended standards for drinking water quality. Furthermore, the health and carcinogenic risks posed to both children and adults were found to surpass the maximum acceptable levels.

A multiobjective [formula omitted]-constraint based approach for the robust master surgical schedule under multiple uncertainties

The efficient scheduling of elective surgeries in hospitals is critical for ensuring patient satisfaction, cost-effectiveness, and overall operational efficiency. However, operating theater (OT) managers face complex and competing scheduling problems due to numerous sources of uncertainty and the impact of the proposed schedule on downstream recovery units, such as the intensive care unit (ICU). To address these challenges, this study develops a multiobjective robust planning model for the weekly Master Surgical Schedule (MSS) under multiple uncertainties. The model takes into account patient priority, assignment cost and workload balancing, while also considering the constraints of the OT, surgeon availabilities, downstream resources, and the uncertainty of surgery duration and patients’ length of stay (LOS) in the ICU. To evaluate the robust solutions, a Monte Carlo simulation is used to calculate the risk of constraint violations, and an adapted ϵ-constraint algorithm is used for the four-objective problem to compute the Pareto front and calculate the hypervolume for every degree of uncertainty. This provides a comprehensive decision tool for OT decision makers and allows for the comparison of various scenarios in terms of the number of scheduled patients, canceled patients, and the utilization rate of the OT.

Assessing landscape N removal in coastal New England catchments using the N-Sink approach with the R Package, nsink

Background Excess nitrogen (N) loading to coastal ecosystems impairs estuarine water quality. Land management decisions made within estuarine watersheds have a direct impact on downstream N delivery. Natural features within watersheds can act as landscape sinks for N, such as wetlands, streams and ponds that transform dissolved N into gaseous N, effectively removing it from the aquatic system. Identifying and evaluating these landscape sinks and their spatial relationship to N sources can help managers understand the effects of alternative decisions on downstream resources. Methods The N-Sink approach uses widely available GIS data to identify landscape sinks within HUC-12 (or larger) catchments, estimate their N removal potential and map the effect of those sinks on N movement through the catchment. Static maps are produced to visualize N removal efficiency, transport and delivery, the latter in the form of an index. The R package nsink was developed to facilitate data acquisition, processing and visualization. Results The R package creates static maps for a specific HUC-12, or users can visit the University of Connecticut website to explore previously mapped areas. Users can also investigate specific flowpaths interactively by clicking on any location within the catchment. A flowpath is generated with a table describing N removal along each segment. We describe the motivation behind developing nsink, discuss implementation in R, and present two use case examples. nsink is available from https://github.com/USEPA/nsink. Conclusions N-Sink is a decision support tool created for local decision-makers to facilitate better understanding of the relationship between land use and downstream N delivery. Local decision-makers that have prioritized N mitigation in their long-term planning can use nsink to better understand the potential impact of proposed development projects and zoning variances. Similarly, land trusts and other NGOs interested in N mitigation can use nsink to identify high priority areas for acquisition or restoration.

How three-dimensional forest structure regulates the amount and timing of snowmelt across a climatic gradient of snow persistence

Across the western United States, forests are changing rapidly, with uncertain impacts on snowmelt water resources. Snow partitioning is controlled by forest effects on interception, radiation, and sublimation. Yet, models often lack snow measurements with sufficiently high spatial and temporal resolution across gradients of forest structure to accurately represent these fine-scale processes. Here, we utilize four Snowtography stations in Arizona, in the lower Colorado River Basin, with daily measurements over 3–5 years at ~110 positions distributed across gradients of forest structure resulting from wildfires and mechanical thinning. We combine Snowtography with lidar snapshots of forest and snow to train a high-resolution snow model and run it for 6 years to quantify how forest structure regulates snowpack and snowmelt. These study sites represent a climate gradient from lower/warmer ephemeral snowpack (~2,100 m asl) to higher/colder seasonal snowpack (~2,800 m asl). Forest cover reduced snowpack and snowmelt through canopy sublimation. Forest advanced snowmelt timing at lower/warmer sites but delayed it at higher/colder sites. Within canopy gaps, shaded cool edges had the greatest peak snow water equivalent (SWE). Surprisingly, sunny/warm gap edges produced more snowmelt than cool edges, because high radiation melted snow quickly, reducing exposure to sublimation. Therefore, peak SWE is not an ideal proxy for snowmelt volume from ephemeral snowpacks, which are becoming more prevalent due to warming. The results imply that forest management can influence the amount and timing of snowmelt, and that there may be decision trade-offs between enhancing forest resilience through delayed snowmelt and maximizing snowmelt volumes for downstream water resources.

Assessing parameter efficient methods for pre-trained language model in annotating scRNA-seq data

Annotating cell types of single-cell RNA sequencing (scRNA-seq) data is crucial for studying cellular heterogeneity in the tumor microenvironment. Recently, large-scale pre-trained language models (PLMs) have achieved significant progress in cell-type annotation of scRNA-seq data. This approach effectively addresses previous methods' shortcomings in performance and generalization. However, fine-tuning PLMs for different downstream tasks demands considerable computational resources, rendering it impractical. Hence, a new research branch introduces parameter-efficient fine-tuning (PEFT). This involves optimizing a few parameters while leaving the majority unchanged, leading to substantial reductions in computational expenses. Here, we utilize scBERT, a large-scale pre-trained model, to explore the capabilities of three PEFT methods in scRNA-seq cell type annotation. Extensive benchmark studies across several datasets demonstrate the superior applicability of PEFT methods. Furthermore, downstream analysis using models obtained through PEFT showcases their utility in novel cell type discovery and model interpretability for potential marker genes. Our findings underscore the considerable potential of PEFT in PLM-based cell type annotation, presenting novel perspectives for the analysis of scRNA-seq data.

Conjunctive use of floodwater harvesting for managed aquifer recharge and irrigation on a date farm in Morocco

AbstractIn arid regions, harvesting floodwater can mitigate irrigation‐induced groundwater depletion by providing additional surface water and recharging aquifers. We designed an experimental protocol to quantify these fluxes on a date farm located along the Wadi Satt, whose flow originates from the Anti‐Atlas Mountains in south‐eastern Morocco. Automatic barometric sensors were used to monitor the water level in a 6500 m3 floodwater harvesting pond and in surrounding boreholes. Six flood events occurred from 2021 to 2023. The pond water balance indicated that most stored water is pumped for irrigation (56% of harvested floodwater). More than 40% infiltrates at a rate of approximately 90 mm day−1, and the remainder evaporated. Analytical modelling of the pond water table system showed that the radius of the piezometric mound resulting from pond infiltration is less than 360 m. Groundwater recharge from the irrigated plot could be observed after two close floods that enabled continuous pumping for several weeks, suggesting that in this specific context, over‐irrigation using surface water allows the aquifer to be recharged. The hydrological effects of possible future expansion of these ponds at the watershed scale should be analysed to assess possible negative impacts on downstream water resources.

An aggregation framework to diagnose the compound hydroclimatic change of the Tibetan Plateau using multiple reanalysis data

Study regionThis study was carried on Tibetan Plateau (TP), which is recognized as the “Third Pole” and “Asia Water Tower”. Study focusTP is suffering extreme hydroclimatic change under global climate warming. Quantifying the hydroclimatic change pattern and strength is necessary to protect local to downstream hydrology and water resources. This study promoted an aggregation framework to diagnose the compound hydroclimatic change on TP using several high-resolution reanalysis data. New hydrological insights for the regionThe promoted aggregation framework is efficient to diagnose the compound hydroclimatic change on TP. Both individual applied data and compound result indicate a warming and wetting environment on most TP, combined with increased trend of evapotranspiration (ET) and soil moisture (SM), while decreased trend of runoff (ROF). The hotspots with strong hydroclimatic change mainly located at inner-southeast TP and northeast TP, including Changtang Plateau, sources of Yellow-Yangtze-Mekong-Salween-Brahmaputra river basin, and Qaidam Basin. The compound warming strength is above 0.06 Celsius/mon/a in winter while the wetting trend is above 0.5 mm/mon/a in summer at most hotspots. ET is increased with trend above 0.1 mm/mon/a in spring, summer, autumn at most hotspots. SM is drying at south periphery while wetting at the remaining area with annual and seasonal trend above 0.0005 mm3/mm3/mon/a at hotspots. ROF is decreased with trend above 2 mm/mon/a at south-southeast hotspots in summer and autumn.

Phosphorus supply and floodplain design govern phosphorus reduction capacity in remediated agricultural streams

Abstract. Agricultural headwater streams are important pathways for diffuse sediment and nutrient losses, requiring mitigation strategies beyond in-field measures to intercept the transport of pollutants to downstream freshwater resources. As such, floodplains can be constructed along existing agricultural streams and ditches to improve fluvial stability and promote deposition of sediments and particulate phosphorus. In this study, we evaluated 10 remediated agricultural streams in Sweden for their capacity to reduce sediment and particulate phosphorus export and investigated the interplay between fluvial processes and phosphorus dynamics. Remediated streams with different floodplain designs (either on one side or both sides of the channel, with different width and elevation) were paired with upstream trapezoidal channels as controls. We used sedimentation plates to determine seasonal patterns in sediment deposition on channel beds and floodplains and monthly water quality monitoring. This was combined with continuous flow discharge measurements to examine suspended sediment and particulate phosphorus dynamics and reduction along reaches. Remediated streams with floodplains on both sides of the channel reduced particulate phosphorus concentrations and loads (−54 µg L−1, −0.21 kg ha−1 yr−1) along reaches, whereas increases occurred along streams with one-sided floodplains (27 µg L−1, 0.09 kg ha−1 yr−1) and control streams (46.6 µg L−1). Sediment deposition in remediated streams was five times higher on channel beds than on floodplains and there was no evident lateral distribution of sediments from channel to floodplains. There was no effect from sediment deposition on particulate phosphorus reduction, suggesting that bank stabilization was the key determinant for phosphorus mitigation in remediated streams, which can be realized with two-sided but not one-sided floodplains. Further, the overall narrow floodplain widths likely restricted reach-scale sediment deposition and its impact on P reductions. To fully understand remediated streams' potential for reductions in both nitrogen and different phosphorus species and to avoid pollution swapping effects, there is a need to further investigate how floodplain design can be optimized to achieve a holistic solution towards improved stream water quality.

Changes in Water Age During Dry‐Down of a Non‐Perennial Stream

AbstractNon‐perennial streams, which lack year‐round flow, are widespread globally. Identifying the sources of water that sustain flow in non‐perennial streams is necessary to understand their potential impacts on downstream water resources, and guide water policy and management. Here, we used water isotopes (δ18O and δ2H) and two different modeling approaches to investigate the spatiotemporal dynamics of young water fractions (Fyw) in a non‐perennial stream network at Konza Prairie (KS, USA) during the 2021 summer dry‐down season, as well as over several years with varying hydrometeorological conditions. Using a Bayesian model, we found a substantial amount of young water (Fyw: 39.1–62.6%) sustained flows in the headwaters and at the catchment outlet during the 2021 water year, while 2015–2022 young water contributions estimated using sinusoidal models indicated smaller Fyw amounts (15.3% ± 5.7). Both modeling approaches indicate young water releases are highly sensitive to hydrological conditions, with stream water shifting to older sources as the network dries. The shift in water age suggests a shift away from rapid fracture flow toward slower matrix flow that creates a sustained but localized surface water presence during late summer and is reflected in the annual dynamics of water age at the catchment outlet. The substantial proportion of young water highlights the vulnerability of non‐perennial streams to short‐term hydroclimatic change, while the late summer shift to older water reveals a sensitivity to longer‐term changes in groundwater dynamics. Combined, this suggests that local changes may propagate through non‐perennial stream networks to influence downstream water availability and quality.

Input-Output Analysis: Which Tax Incentive for Natural Resources Downstream Is Suitable for Indonesian Economy?

Indonesian government's policy to promote downstream natural resources leads to tax incentives policy intended to encourage the downstream. This study focuses on corporate income tax incentives in the form of net income reduction (tax allowance according to Article 31A of the Income Tax Law) by 30 percent for 6 years or corporate income tax reduction (tax holiday according to Minister of Finance Regulation Number 130/PMK.010 /2020) by 100 percent or 50 percent. Despite the positive or negative impact of tax incentives enactment argued in the previous studies, this study will calculate the impact on the economy provided by the mentioned tax incentive schemes quantitatively and will analyze which tax incentive scheme gives the greater impact on the economy. The analysis was carried out by using input-output analysis method to calculate the impact from output approach on secondary data in the form of the latest input output table released by Badan Pusat Statistik i.e., 2016 input output table. The result of the study shows that tax incentive in the form of tax holiday with income tax reduction by 100 percent provides greater impact on the economy than the others do. The total impact is getting greater and shows comparable results as the tax incentive rate increases. However, the result of this study implies that the implementation of tax incentives still needs the right tax incentive policy design to gain the expected results.

Optimizing the Flood Limit Water Level of Reservoirs in Sediment-Laden Rivers under Changing Water and Sediment Conditions: A Case Study of the Xiaolangdi Reservoir

Optimizing the flood limit water level (FLWL) of reservoirs in sediment-laden rivers under changing water and sediment conditions is an important research topic that could improve comprehensive utilization benefits. Because reservoir operation has multiple objectives in sediment-laden rivers, this study established a water–sediment mathematical model, a comprehensive benefit evaluation model, and an evaluation index system. Taking the Xiaolangdi Reservoir of the Yellow River as an example, the operation mode of the FLWL under changing water and sediment conditions was studied. Under the scenarios of incoming sediment amounts of 300–800 million tons, when using the operation mode of gradually raising the FLWL, the sediment retention period was 4–13 years longer; the lower average annual siltation of the downstream channel and minimum bank-full discharge of the downstream channel after 50 years was larger by 150–260 m3/s than the operation mode of raising the FLWL at one time. However, with enhanced benefits of sediment blocking and siltation reduction, other benefits such as water resources supply, hydropower generation, and ecological improvement are reduced. The average annual number of days that do not meet the downstream water resources supply requirements, irrigation, and ecological improvement was increased by 0.64–2.16 days, and 91–197 million kW·h reduced average annual hydropower generation. The critical amount of incoming sediment was 350 million for conversion between the two FLWL operation modes, and it will increase to 450 million tons if the incoming runoff of the Yellow River increases by 20%. After constructing the Guxian Reservoir in the middle of the Yellow River, the critical amount of incoming sediment will increase to 600 million tons. This study is of great significance for improving the utilization efficiency of water resources and promoting the socio-economic development of river basins.

Nutrient retention in a small reservoir under changed variability of inflow nutrient concentration

ABSTRACT Within freshwater networks, lakes and reservoirs are reactors that modify nutrient dynamics. Their functioning is based on an interplay of hydrological and biogeochemical processes, rendering them vulnerable to climate change. Future changes in catchment characteristics are likely to alter the timing and magnitude of nutrient concentrations in discharge. This study investigated the impact of changing variability of nutrient concentrations on lake and reservoir dynamics. We examined intraannual nutrient retention and analyzed the role of reservoirs in reconfiguring the variability of nutrients. Utilizing the 1D lake model GOTM-WET, we simulated nutrient processing in a mesotrophic reservoir. Further, we performed scenario simulations by modifying the variability of inflow nitrogen and phosphorus concentrations. Our findings indicate that the reservoir removed ∼4% and ∼12% of total nitrogen (TN) and total phosphorus (TP), respectively. Particulate fractions were retained efficiently, but there was a net export of dissolved organic fractions. Regarding mixing and stratification periods, however, we observed net nitrogen export during stratification in certain years. During stratification, outflow concentration variability remained relatively unchanged for TN and TP compared to inflow concentrations. Conversely, phosphate and nitrate concentration variability increased in the outflow because of in-lake assimilation and the influence of hydrological events. With increasing inflow concentration variability during stratification, there was decreased removal of TN and TP by the reservoir, but increased variability of concentration. By evaluating the lake's capacity to attenuate variability of nutrient inflows under altered conditions, there are opportunities to improve monitoring of nutrient export and evaluate the potential impact of nutrient peaks on downstream drinking water resources and ecosystems.

Effects of Snow Water Storage on Hydrologic Partitioning Across the Mountainous, Western United States

AbstractIn the montane western United States, where the majority of downstream water resources are derived from snowmelt, a warming climate threatens the timing and amount of future water availability. It is expected that the fraction of precipitation falling as snow will continue decreasing and the timing of snowmelt will continue shifting earlier in the year with unknown impacts on partitioning between evapotranspiration and streamflow. To assess this, we employ a Snow Storage Index (SSI) to represent the annual temporal phase difference between daily precipitation and daily modeled surface water inputs (SWI, the sum of rainfall and snowmelt), weighted by the respective amounts. We coupled the SSI metric with a Budyko‐based framework to determine the effect of snow water storage on relative hydrologic partitioning across snow‐influenced watersheds in the western U.S. Greater snow water storage was positively correlated with greater hydrologic partitioning to streamflow, particularly in the North Cascades/Cascades (r2: 0.62), Blue Mountains (r2: 0.56), Canadian Rockies (r2: 0.55), Idaho Batholith, (r2: 0.48), and Columbia Mountains/Northern Rockies (r2: 0.45). The weekly SWI:P ratio was an equally strong predictor for hydrologic partitioning, particularly in mid‐spring (e.g., March/April) in the same mountainous areas (r2: 0.62–0.74, across the same eco‐regions). The retention of snow water storage and subsequent release of stored water in summer months resulted in increased hydrologic partitioning to streamflow. If SSI decreases with future warming, the volume of water partitioned streamflow will decrease non‐uniformly across the western U.S. with substantial implications for ecosystems and agricultural, industrial, and domestic water supplies.

Basin water ecological compensation interval accounting based on dual perspectives of supply and consumption: Taking Qingyi River Basin as an example

Basin water ecological compensation is an effective means of coordinating environmental protection and economic development and promoting sustainable development. A reasonable compensation interval (the value range of the compensation standard) is the basis for final pricing. At present, the calculation method of the compensation interval has not been unified in the current research, and it is rarely considered comprehensively from the perspective of both parties of compensation. Based on the perspectives of upstream water resources suppliers and downstream water resources consumers, this paper proposes a water ecological compensation interval accounting method based on emergy analysis theory and water ecological footprint method. From the perspective of the supply side, the remaining ecological economic system services value supplied by the upstream area is taken as the lower limit; from the perspective of the consumer side, the value of ecological economic system services actually occupied by downstream areas is taken as the upper limit. Taking the Qingyi River Basin as an example, the results show that there is a serious ecological deficit in the lower reaches of the Qingyi River Basin, and reasonable compensation needs to be given to the supplier Xinzheng City; the accounting method based on dual perspectives is better than traditional. The method is more precise and greatly shortens the value range of the compensation standard. This study provides a novel and complete ecological compensation interval accounting method, which provides a more accurate and reasonable reference for the determination of ecological compensation standards in the basin, and helps the government to improve and implement the ecological compensation mechanism.

Using thermal UAV imagery to model distributed debris thicknesses and sub-debris melt rates on debris-covered glaciers

AbstractSupraglacial debris cover regulates the melt rates of many glaciers in mountainous regions around the world, thereby modifying the availability and quality of downstream water resources. However, the influence of supraglacial debris is often poorly represented within glaciological models, due to the absence of a technique to provide high-precision, spatially continuous measurements of debris thickness. Here, we use high-resolution UAV-derived thermal imagery, in conjunction with local meteorological data, visible UAV imagery and vertically profiled debris temperature time series, to model the spatially distributed debris thickness across a portion of Llaca Glacier in the Cordillera Blanca of Peru. Based on our results, we simulate daily sub-debris melt rates over a 3-month period during 2019. We demonstrate that, by effectively calibrating the radiometric thermal imagery and accounting for temporal and spatial variations in meteorological variables during UAV surveys, thermal UAV data can be used to more precisely represent the highly heterogeneous patterns of debris thickness and sub-debris melt on debris-covered glaciers. Additionally, our results indicate a mean sub-debris melt rate nearly three times greater than the mean melt rate simulated from satellite-derived debris thicknesses, emphasising the importance of acquiring further high-precision debris thickness data for the purposes of investigating glacier-scale melt processes, calibrating regional melt models and improving the accuracy of runoff predictions.