River Range Research Articles

Global risk assessment of river pollution stress based on nighttime light remote sensing data

Rivers play a crucial role in the development of human civilization, and river pollution is a significant environmental issue that accompanies with intensified human activity. However, the evaluation of river pollution at a global scale is difficult because of the limitations of long-term pollution-related datasets. As human activities are the main factor causing river pollution, nighttime light (NTL) remote sensing data can be used as an alternative indicator of the risk of river pollution stress(RPS), which is closely related to human activities and refers to the amount of pollutants within the confluence range of river reaches. In this study, we propose a river pollution pressure index (PI) to indicate risk of RPS by considering the accumulation effect of water flow. Then we calculated PI of over 0.67 million reaches global with annual total flow >100 million m3/s from 2000 to 2022, which was validated using water quality data of >2000 river sections in China. The results show that, from 2000 to 2022, the spatial variations of the risk of RPS are uneven, with a migration trend from west to east. The risk of RPS continues to increase globally, especially rapidly after 2010. Central Asia, Southeast Asia, East Asia, and eastern China are the regions with the fastest growth rates. In most developed countries, developing countries, and underdeveloped countries, the risk of RPS is high and increasing slowly, moderate and increasing rapidly, and low and increasing slowly, respectively. However, in some special cases, such as Japan, the risk of RPS continues to decrease. These spatiotemporal variations of the risk of RPS correlate with global events, such as quantitative easing of global economy after 2008, China's “Belt and Road Initiative”, and COVID-19. This study demonstrates that NTL data can be applied to evaluate the global risk of RPS.

Glacier Meltwater Impacts to Late Summer Flow and Geochemistry of Tributaries in the Wind River Range, Wyoming, USA

Reductions in winter snowpack over the last few decades have affected water resource availability in the western United States. In regions where glaciers exist, local communities have an advantage over nonglaciated regions as water continues to flow once the snowpack has melted. Despite this advantage, relatively little is understood about the contributions of glacial meltwater quantity and quality to streamflow. Torrey Creek watershed in the Wind River Range, Wyoming, contains several glaciers that provide meltwater to supplement late summer streamflow to the Wind River. Despite its importance as a contributor to water resources in the region, Torrey Creek discharge is not regularly monitored. Field research conducted in August 2019 for this study, along with previous field work completed in August 2012 and 2014, provides some understanding of late summer meltwater quantity and quality within the Torrey Creek watershed. Measured Torrey Creek discharge during mid-August 2019 averaged 3.80 m³ s−1 with 37 percent of the discharge attributed to glacial ice melt from stable isotope analysis. Nutrient loading to Torrey Creek from glacial meltwater was dominated by NO2–NO3 at 179.99 kg per month followed by 21.86 kg of total P for August 2019.

Wind Riders of the Lost River Range: A Modular Project-Based Case for Software Development

The Wind Riders of the Lost River Range (WRLRR) is a modular project-based simulated case study. This case study is designed to accompany a hands-on collaborative semester project for a variety of software development courses. The case can be used in courses like Systems Analysis and Design, Database Design, Software Engineering, and Software Development. The case provides a detailed account of a situation that closely simulates a real-world problem. This challenging experiential learning opportunity reinforces course concepts through their application in a realistic scenario. WRLRR has been developed using the modular design of teaching cases approach. This approach makes it possible to swap modules in and out of the case. This reduces instructor workload by making it unnecessary to develop a new case from scratch for each course iteration. It also discourages students from recycling solutions from previous courses because the case scenario has been altered. Adding or removing modules makes it possible to sufficiently vary the case study to refine the problem being addressed. Macros are provided to automate, and thereby facilitate, the insertion of modules.

Occurrence and environmental risk assessment of 4 estrogenic compounds in surface water in Belgiumin the frame of the EU Watch List.

The presence of natural estrogens estrone (E1), 17β-estradiol (E2), estriol (E3) and synthetic estrogen 17α-ethynylestradiol (EE2) in the aquatic environment has raised concerns because of their high potency as endocrine disrupting chemicals. The European Commission (EC) established a Watch List of contaminants of emerging concerns including E1, E2 and EE2. The proposed environmental quality standards (EQSs) are 3.6, 0.4, 0.035ng/L, for E1, E2, EE2, respectively. A thorough evaluation of analytical procedures developed by several studies aiming to perform sampling campaigns in different European countries highlighted that the required limits of quantification in surface water were not reached, especially for EE2 and to a lesser extent for E2. Moreover, data regarding the occurrence of these contaminants in Belgian surface water are very limited. A sampling campaign was therefore performed on a wide range of rivers in Belgium (accounting for a total of 63 samples). The detection frequencies of E1, E2, E3 and EE2 were 100, 98, 86 and 48%, respectively. E1 showed the highest mean concentration (= 4.433ng/L). In contrast, the mean concentration of EE2 was 0.042ng/L. The risk quotients (RQs) were calculated based on the respective EQS of each analyte. The frequency of exceedance of the EQS was 31.7% for E1, EE2, while it increased to 44.4% for E2. The extent of exceedance of the EQS, represented by the 95th percentile of the RQ dataset, was higher than 1 for E1, E2, EE2. The use of a confusion matrix was investigated to try to predict the risk posed by E2, EE2, based on the concentration of E1.

Modeling the effects of levee setbacks on flood hydraulics

AbstractRelocating levees further back from river channels to increase river–floodplain connection can reduce flood stages and provide a host of co‐benefits. Modeling case studies show the significant potential of large levee setbacks for reducing flood stages; however, the difficulty of comparing between these case studies limits our understanding of how the hydraulic effects of setbacks vary in different settings. We filled this research gap by systematically modeling the hydraulic effects of setbacks across a range of river and flood conditions. We used unsteady, 1D Hydrologic Engineering Center‐River Analysis System models to quantify changes in flood stage, channel velocity, and sediment transport capacity for various setback sizes with different river slopes, widths, floodplain roughness, and flood sizes (peak flows) and durations. Setbacks reduce flood stages within the setback, as well as up‐ and downstream. Channel velocity and sediment transport capacity both increased upstream and decreased within the setback. Channel slope, flood size, and flood duration had the largest influence on hydraulic changes. There are diminishing returns in hydraulic effects with increasing setback size. These results can help guide the design and prioritization of levee setback projects and help set reasonable expectations for the scale of changes to flood hydraulics relative to the size of the reconnected floodplain.

The utility of alpine cave fossil assemblages for zoological census: an example from northern Utah, United States

Abstract Assemblages of mammal skeletal remains provide a powerful tool for censusing wildlife populations to establish zoological baselines required for evaluating biogeographic trends over varying timescales. Caves provide an ideal depositional setting to preserve these skeletal remains despite potential time averaging and taphonomic filtering. We describe a Holocene paleontological assemblage from Boomerang Cave in the Bear River Range of Cache County, northern Utah, United States, at an elevation of 2,231 m, and at the boundary between the Great Basin and Rocky Mountain biogeographic provinces. We analyzed 1,228 surface-collected specimens from six areas within the cave, and identified a minimum of 22 nonoverlapping mammalian taxa, comprising all size classes present in the region. Compared to museum records for mammals from the Bear River Range and individuals trapped or observed in the vicinity of the cave, specimen-based rarefaction demonstrates that our assemblage captures most of the mammalian diversity expected in the area. This is particularly apparent for carnivorans and soricids, which are particularly well-represented in the Boomerang Cave assemblage, with the former clade represented by at least nine taxa. This high level of diversity can be attributed to the relatively random nature of natural trap cave deposition, reducing accumulation biases due to size or diet. We also record the first occurrence of Merriam’s Shrew (Sorex merriami) from the Bear River Range. Our analysis does not indicate any mammalian changes between late Holocene and present-day communities, but these data establish a new zoological baseline for an alpine community at the interface between two key biogeographic provinces in western North America. Our work highlights the value of collecting skeletal remains from cave assemblages as a convenient and fast method for censusing terrestrial mammalian communities.

Propagation characteristics of the flow and suspended sediment peaks in the three gorges reservoir, China: Insight from numerical simulations and measured data

AbstractEffective management of reservoir sedimentation necessitates the characterization of flood events, especially in relation to the propagation of the flow peak (Qpeak) and the suspended sediment concentration peak (SSCpeak). This study, based on a one‐dimensional river network hydro‐sediment model together with field data, presents an exploration of the flood events in the Three Gorges Reservoir (TGR) with focus on the propagating characteristics of Qpeak and SSCpeak. The findings reveal that the main flood season (from July to September) contributed over 80% of the annual sediment load into the TGR, with the mainstream Yangtze and its tributary, the Jialing River, being the primary sediment sources. After the impoundment of the TGR, the propagation time of Qpeak decreases with the raise of the water level in front of dam (WLdam). The increases in Qpeak discharge extends the range of river reach dominated by kinematic wave, resulting in an increase trend in Qpeak propagation time. The propagating speed of SSCpeak is closely related to the ratio of sediment concentration to flow discharge and WLdam. Finally, the propagating durations of Qpeak and SSCpeak in the TGR are compared, and empirical formulas are proposed for quantifying their difference.

The pre-Jurassic Meng-Shaan paleochannel and its control on the accumulation model of Yan 10 reservoir in Central Ordos Basin

In the setting of the increasing density of exploration wells, and the decreasing scale and increasing difficulty of discovering Jurassic paleogeomorphology reservoirs, it is urgent to deepen the fine depiction of pre-Jurassic paleogeomorphology features and to analyze their controlling effect on reservoirs. Based on abundant logging data combined with indoor microscopic observation and experimental testing, the paper applies the theory of reservoir configuration analysis for the first time to the single-channel period division of the pre-Jurassic Meng-Shaan paleochannel which deposited with the braided channel sand bodies. Meanwhile, it reveals the controlling effect of hydrocarbon accumulation and the distribution characteristics of the Yan 101 reservoir as ' paleogeomorphology and sedimentary facies combination' to determine the type, 'migration channel' to determine the distributing range, and 'low-amplitude structure' to determine the trap in the study area, and also the reservoir accumulation modes in different channel ranges have established. In conclusion, the single-channel boundary of the Meng-Shaan paleochannel in different periods controls the path of oil and gas migration, thus controlling the distribution range and reservoir type of the Yan 10 reservoir. Moreover, depending on the production data we derived that it should prefer the composite trap reservoir of the Fuxian period and the Yan 102 period, as well as the structural reservoir on the periphery of the Yan 102 period single-channel for the further exploration of the Yan 10 paleogeomorphology reservoirs within the development range of the Meng-Shaan ancient river. In particular, the lithologic trap reservoirs within the Fuxian period channel and the Meng-Shaan main channel, such as the reservoirs of the 'Source' of the secondary channel type and the paleochannel type, which could as a replacement accumulation model for increasing reserves and production.

Determination of River Ecological Base Flow Based on the Coupling Relationship of Sediment–Water Quality–Biodiversity in Water Shortage Area of Northwest China

Maintaining the integrity of ecosystem service functions of rivers has become the top issue in the water shortage area of Northwest China. By combining the coupling relationship of sediment, water quality, and biodiversity and the hydraulic relationship of the section, we established a quantitative calculation method for the river ecological base flow, which is mainly divided into the following three steps: first, we determined the reasonable ecological flow velocity range of rivers via water purification, maintaining the river geometry and biodiversity; second, we combined the hydraulic relationship between the river ecological velocity range and the river ecological base flow to determine the protection target of the river ecological base flow; finally, we combined the remaining water volume of rivers and ecological base flow protection target of rivers to determine their protection rate. Take the Baoji section of the Weihe River as an example: the results show that the ecological base flow in the Baoji section of the Weihe River is [6.26, 9.17 m3/s] and [32.94, 38.93 m3/s] from October of this year to May of next year and from June to September, respectively, and the protection rates of the ecological base flow for five typical years are 62.47%, 41.10%, 16.16%, 15.07%, and 10.68%. These coupling methods can also be used in the world’s river basin, which has similar problems.

Unexpected low CO2 emission from highly disturbed urban inland waters

Constituents and functionality of urban inland waters are significantly perturbed by municipal sewage inputs and tailwater discharge from wastewater treatment plants. However, large knowledge gaps persist in understanding greenhouse gas dynamics in urban inland waters due to a lack of in situ measurements. Herein, via a 3-year field campaign (2018–2020), we report river and lake CO2 emission and related aquatic factors regulating the emission in the municipality of Beijing. Mean pCO2 (546 ± 481 μatm) in the two urban lakes was lower than global non-tropical freshwater lakes and CO2 flux in 47% of the lake observations was negative. Though average pCO2 in urban rivers (3124 ± 3846 μatm) was among the higher range of global rivers (1300–4300 μatm), average CO2 flux was much lower than the global river average (99.7 ± 147.5 versus 358.4 mmol m−2 d−1). The high pCO2 cannot release to the atmosphere due to the low gas exchange rate in urban rivers (average k600 of 1.3 ± 1.3 m d−1), resulting in low CO2 flux in urban rivers. Additionally, eutrophication promotes photosynthetic uptake and aquatic organic substrate production, leading to no clear relationships observed between pCO2 and phytoplankton photosynthesis or dissolved organic carbon. In consistence with the findings, CO2 emission accounted for only 32% of the total greenhouse gas (GHG) emission equivalence (CO2, CH4 and N2O) in Beijing waters, in contrast to a major role of anthropogenic CO2 to anthropogenic GHG in the atmosphere in terms of radiative forcing (66%). These results pointed to unique GHG emission profiles and the need for a special account of urban inland waters in terms of aquatic GHG emissions.

Parallel shifts in trout feeding morphology suggest rapid adaptation to alpine lake environments.

Eco-evolutionary interactions following ecosystem change provide critical insight into the ability of organisms to adapt to shifting resource landscapes. Here we explore evidence for the rapid parallel evolution of trout feeding morphology following eco-evolutionary interactions with zooplankton in alpine lakes stocked at different points in time in the Wind River Range (Wyoming, USA). In this system, trout predation has altered the zooplankton species community and driven a decrease in average zooplankton size. In some lakes that were stocked decades ago, we find shifts in gill raker traits consistent with the hypothesis that trout have rapidly adapted to exploit available smaller-bodied zooplankton more effectively. We explore this morphological response in multiple lake populations across two species of trout (cutthroat trout, Oncorhynchus clarkii, and golden trout Oncorhynchus aguabonita) and examine the impact of resource availability on morphological variation in gill raker number among lakes. Furthermore, we present genetic data to provide evidence that historically stocked cutthroat trout populations likely derive from multiple population sources, and incorporate variation from genomic relatedness in our exploration of environmental predictors of feeding morphology. These findings describe rapid adaptation and eco-evolutionary interactions in trout and document an evolutionary response to novel, contemporary ecosystem change.

Study of Urban Flooding Response under Superstandard Conditions

Superstandard conditions refer to extreme rainfall and river flooding that exceed the flood control system or flood control works. In order to explore the influence of superstandard conditions on urban waterlogging, based on the MIKE FLOOD platform, this paper takes the downtown area of Zhoukou as the research object, and it conducts waterlogging simulation in this area under the extreme rainfall conditions of once in 20 years and once in 50 years combined with the ultra-high water level of the river. The simulation results of inundation depth, inundation range and drainage capacity of a self-flowing river are compared and analyzed. The results show that heavy rainfall is the main cause of waterlogging disaster. When extreme rainfall and river flood occur at the same time, the artesian drainage capacity of the pipeline is seriously affected due to the high water level of the river. The city has a large amount of water, and when the river embankment overflows, it poses a serious threat to the safety of the city.

A Numerical Evaluation of the Impact of Operational Ground-Based Glaciogenic Cloud Seeding on Precipitation over the Wind River Range, Wyoming

Abstract This study evaluates an operational glaciogenic cloud-seeding program using ground-based generators of silver iodide (AgI), with a total of 190 seeded storms over 10 cold seasons, using the Weather Research and Forecasting Weather Modification (WRF-WxMod) scheme at 900-m grid spacing. This study examines both the quantitative change in precipitation and the ambient and cloud conditions impacting seeding efficacy. An ensemble approach is used, with differing model boundary conditions, ice nucleation physics, concentrations of cloud condensation nuclei, and boundary layer schemes. This is intended to provide an envelope of uncertainty of natural clouds and seeding impacts. The simulations are validated against radiosonde, snow gauge, and microwave radiometer observations, and the seeding impact is inferred from simulations with/without AgI seeding. The seeding-induced precipitation enhancement (“yield”) varies greatly between storms. A small portion of the cases produces the majority of the yield. Overall, the precipitation in the target area (the Wind River Range in Wyoming) increased by 1.10% ± 0.13% in the 10 years of operational seeding. This rather low fractional increase is related to the frequent seeding at unsuitable times, primarily because of low-level flow blocking. The flow and cloud structure for select cases are examined to provide better insight into the variability of yield. Cases with unblocked surface flow and abundant cloud liquid water tend to be the most productive. The technique presented here can be readily adapted to evaluate the seeding impact of other long-term glaciogenic seeding operations and to improve their operational efficiency. Significance Statement In the United States and elsewhere, there are several operational programs to enhance cold-season precipitation through glaciogenic seeding of orographic clouds. The impact of such activity on seasonal precipitation has always been difficult to quantify. Recent observational and numerical modeling studies indicate that orographic cloud seeding can increase precipitation, although the amounts and optimal seeding conditions remain uncertain. Operators lack guidance about the seeding efficacy and about the most suitable environmental conditions. In recent years a model parameterization, called Weather Research and Forecasting Weather Modification (WRF-WxMod), has been tested against detailed measurements. This sets the stage for our work, a well-designed numerical evaluation of 10 years of operational cloud seeding over the Wind River Range, a mountain range in Wyoming that feeds the Colorado River basin and other watersheds. The WRF-WxMod based simulation experiment presented here, one of the most computationally expensive numerical experiments on this subject to date, quantifies seeding impact and its uncertainty. It is demonstrated with a high degree of confidence that over this 10-yr period, suitable seeding conditions were rare over this mountain range, that most seeding events were unproductive, and that, as a result, the overall yield over 10 years was a mere 1.1%.

Diverse portfolios: Investing in tributaries for restoration of large river fishes in the Anthropocene

Rehabilitation of large Anthropocene rivers requires engagement of diverse stakeholders across a broad range of sociopolitical boundaries. Competing objectives often constrain options for ecological restoration of large rivers whereas fewer competing objectives may exist in a subset of tributaries. Further, tributaries contribute toward building a “portfolio” of river ecosystem assets through physical and biological processes that may present opportunities to enhance the resilience of large river fishes. Our goal is to review roles of tributaries in enhancing mainstem large river fish populations. We present case histories from two greatly altered and distinct large-river tributary systems that highlight how tributaries contribute four portfolio assets to support large-river fish populations: 1) habitat diversity, 2) connectivity, 3) ecological asynchrony, and 4) density-dependent processes. Finally, we identify future research directions to advance our understanding of tributary roles and inform conservation actions. In the Missouri River United States, we focus on conservation efforts for the state endangered lake sturgeon, which inhabits large rivers and tributaries in the Midwest and Eastern United States. In the Colorado River, Grand Canyon United States, we focus on conservation efforts for recovery of the federally threatened humpback chub. In the Missouri River, habitat diversity focused on physical habitats such as substrate for reproduction, and deep-water habitats for refuge, whereas augmenting habitat diversity for Colorado River fishes focused on managing populations in tributaries with minimally impaired thermal and flow regimes. Connectivity enhancements in the Missouri River focused on increasing habitat accessibility that may require removal of physical structures like low-head dams; whereas in the Colorado River, the lack of connectivity may benefit native fishes as the disconnection provides refuge from non-native fish predation. Hydrologic variability among tributaries was present in both systems, likely underscoring ecological asynchrony. These case studies also described density dependent processes that could influence success of restoration actions. Although actions to restore populations varied by river system, these examples show that these four portfolio assets can help guide restoration activities across a diverse range of mainstem rivers and their tributaries. Using these assets as a guide, we suggest these can be transferable to other large river-tributary systems.

Inversion of river discharge from remotely sensed river widths: A critical assessment at three-thousand global river gauges

Accurately estimating river discharge from satellite-derived river hydraulic variables (e.g., width, height, and slope) is the overarching goal of the remote sensing of discharge (RSQ) community. Numerous past studies have developed and intercompared different RSQ algorithms to demonstrate their feasibility, yet relatively few have focused on assessing how the RSQ algorithms are adapted to a wide range of rivers globally. As the community is now ready to expand to the global scale given advances in computing power, sensors, and the launch of the Surface Water and Ocean Topography (SWOT) satellite mission, a much broader geographic view of RSQ accuracy should be prioritized toward “better generalizability” instead of “higher accuracy at limited places”. To help close this gap, we extracted multi-temporal river widths from >350 K Landsat scenes at >3 K river reaches globally, and used them to estimate discharge using the Bayesian AMHG-Manning (BAM) algorithm and the geomorphologically-enhanced variant (geoBAM). We use this framework to demonstrate how to apply an ‘off the shelf’ RSQ algorithm and test it globally without methodological intervention and answer: does it live up to its promise? Our daily discharge inversions (1984–2019) showed positive Kling-Gupta Efficiency (KGE) at 27% of the gauges for BAM and 39% for geoBAM, and this percentage increased to 46–65% after feeding richer priors on flow seasonality and monthly variability, amounting to 1400–2000 successful inversions. Exploratory analyses showed that the inversion is the most sensitive to a channel geomorphological parameter b and climate aridity, where the optimal conditions are high-b, humid environments, as well as moderate width variability, leaf area index (LAI), and river width. Although specific to BAM/geoBAM, constraining the factors to their optimal ranges led to a median KGE of 0.33 for >600 gauges, which highlights the promising potential for global RSQ. We further discussed the optimal configuration of the RS/priors by analyzing results derived from different information content in priors. Overall, our critical assessment of BAM/geoBAM reveals a successful global implementation of an existing algorithm that SWOT will improve. We suggest similar large-scale assessments for other RSQs be prioritized to identify the emerging challenges as we move into a new era with global river monitoring capability from space.

Moving Aircraft River Velocimetry (MARV): Framework and Proof‐of‐Concept on the Tanana River

AbstractInformation on velocity fields in rivers is critical for designing infrastructure, modeling contaminant transport, and assessing habitat. Although non‐contact approaches to measuring flow velocity are well established, these methods assume a stationary imaging platform. This study eliminates this constraint by introducing a framework for moving aircraft river velocimetry (MARV). The workflow takes as input images acquired from an airplane and involves orthorectification, frame overlap analysis, image enhancement, particle image velocimetry (PIV), and aggregation of the resulting velocity vectors onto a prediction grid. We also use new metrics to quantify the agreement between image‐derived and field‐measured velocity vectors in terms of both orientation and magnitude. The potential of MARV was evaluated using data from two Alaskan rivers: a large, highly turbid channel and its smaller, clearer tributary. Sediment boil vortices on the mainstem provided natural features trackable via PIV and estimated velocities corresponded closely with field measurements (R2 up to 0.911). We compared an exhaustive approach that evaluates overlap for all frame combinations to a simpler rolling window implementation and found that the more efficient algorithm did not compromise accuracy. Sensitivity analysis suggested that the method was robust to window parameterization. Comparing PIV output from different flying heights and imaging systems indicated that larger pixels led to higher accuracy and that a more advanced dual‐camera system provided superior performance. Results from the tributary were less encouraging, presumably due to a lack of trackable features in visible images. Testing across a range of rivers is needed to assess the generality of MARV.

Outdoor thermal comfort of urban river landscape belt in China's cold region: A case study of Xi'an

The outdoor thermal sensation and comfort questionnaires was conducted on the River Ba landscape belt of Xi'an city located in the cold region of China. The survey included objective micrometeorological measurements and subjective questionnaire surveys in winter, summer and spring. The study contrasted the outdoor thermal comfort of the river landscape belt in different seasons in cold region. Physiological equivalent temperature (PET) was used as a thermal comfort index to quantitatively analyze the thermal comfort range of urban river in Xi'an. The 80% thermal acceptable PET range in Xi'an was 14.3 °C–19.9 °C in winter, 17.3 °C–24.6 °C in spring, and 17.6 °C–31.8 °C in summer. During winter, spring, and summer, the neutral PET was 21.7 °C, 20.5 °C, and 18.9 °C, respectively. Due to seasonal adaptation, “slightly warm” in spring and winter was considered the most comfortable thermal sensation, while “neutral to cool” was regarded as the most comfortable in summer. The importance of thermal experience and psychological adaptation was found, thermal sensation voting was lower in early spring than in winter for the same PET, and the locals were acceptable even if not within the comfort PET range.

Changes in snow and ice surface albedo and its impact on snow and ice area in the Wind River Range, Wyoming, USA

ABSTRACT Glacial and snow melt in the Wind River Range, Wyoming feed headwaters for the Missouri and Colorado River Systems, covering much of the western United States. Identifying the factors that have the greatest impact on snow and ice melt is important to managing the water resources in this region. This study examined snow and ice albedo, summer temperature and precipitation, and winter precipitation as potential significant factors related to snow and ice area changes. The Mann–Kendall statistical test was used to analyze changes in surface albedo on snow and ice over time (1985 to 2016) as derived from Landsat imagery among 5 basins in the Wind River Range. As well, a stepwise regression analysis was utilized in determining the significance of albedo along with summer mean temperature, total summer precipitation, and total winter precipitation in predicting snow and ice area. Among all the variables, albedo was found to have the greatest significance in relation to snow and ice area change. The significance of albedo on snow and ice melting in the Wind River Range is likely due to a positive feedback effect coupled with possible effects from annual increases in particulates from forest fires and fossil fuel production.

Spatio-temporal dynamics of fish assemblage in the Datong and Xiaotong rivers, karst tributaries in the upper Yangtze River drainage: Implications for ecological adaptation and conservation of fish in rivers

The Datong and Xiaotong rivers are karst tributaries in the upper Yangtze River drainage and represent considerable habitat diversity that contributes to high fish diversity and rich fishery resources in the two rivers. During the few decades, fish resources have abruptly declined due to overfishing, water pollution and habitat degradation. In order to further strengthen conservation and restoration of fish resources and provide scientific support for fishery management in these rivers, the temporal and spatial dynamics of fish assemblage in the Datong and Xiaotong rivers were investigated in the present study. A total of 45 species were captured at 30 sample sites during four surveys conducted from March 2016 to January 2017. Species diversity and richness both increased from upstream to downstream in the two rivers. The fish assemblages significantly differed between river reaches, while did not differ in significantly between 4 months. The spatial variations in the abundance of Rhynchocypris oxycephalus, Zacco platypus, Triplophysa bleekeri, Sinogastromyzon szechuanensis, Platysmacheilus nudiventris, Sinibrama taeniatus, Saurogobio gymnocheilus, Pseudorasbora parva, Pseudobagrus truncates and Opsariichthys bidens were considered to contribute most to the spatial pattern of fish assemblages. The lack of a temporal pattern of the fish assemblage in the rivers might be attributed to ecological habits of short-distance migration and diversified mesohabitats with riffles and pools for fish spawning, feeding or overwintering within a very short river range. Our results suggest the spatio-temporal dynamics of fish assemblages is highly adapted to the habitat characteristics in the two karst rivers. We recommend that fish conservation of these tributaries be focused on the mesohabitats, particularly the many pools and riffles.

Analysis of Distribution of Flood Disaster Hazard in Tangerang City

Tangerang City was largest city in Banten Province with total area of 184.23 km2. Tangerang City was generally combination of coastal areas with lowlands condition which is located along Cisadane River. Mapping of flood-prone areas in Tangerang City aims to identify areas which have potential for flooding, so these areas can be analyzed for preventing action. In this research, flood-prone areas were identified using scoring method. The flood parameters consist of land height, slope, rainfall, soil type, land cover, and river range. Spatial information was represented in form of map, while attributes of spatial information were represented in tabular form using different parameters and weight values in mapping flood hazard in Tangerang City. The results show us that level of flood hazard in Tangerang City was divided into four classes of hazard, namely level of flood hazard “safe” in Benda District with area of 0,831 Ha, level of flood hazard “slightly vulnerable” in Jatiuwung District with area of 155,897 Ha, level of flood hazard “Prone” occur in Pinang District, which has area of 1.360,161 Ha, while level of flood hazard “very vulnerable” was in Benda District, which has area of 1.358,454 Ha.