• Issue
    Volume 35, Issue 1
    1-3
    January 2021

ISSUE INFORMATION

Free Access

Issue Information

  • Pages: 1-3
  • First Published: 12 January 2021

WILDFIRE AND HYDROLOGICAL PROCESSES

Effectiveness of post-fire salvage logging stream buffer management for hillslope erosion in the U.S. Inland Northwest Mountains

  • First Published: 14 October 2020
Description unavailable

Ground-based salvage logging is often used to recover economic loss of burned timber. This experiment tested stream buffer width effectiveness with a novel sediment-laden simulated rill experiment after a high severity wildfire. Two months after the fire, highly burned areas had rills up to 100 m long that decreased in length over time as vegetation regrowth occurred. Sediment concentration and sediment dropout rate also varied significantly by soil burn severity. These results suggest that stream buffers on high soil burn severity sites need to be eight times greater (120 m) immediately after wildfire and four times greater (60 m) 1-year post-fire as compared to a standard 15-m unburned buffers.

Increased colluvial hollow discharge and subsequent recovery after a low intensity wildfire in the Blue Ridge Mountains, USA

  • First Published: 13 November 2020
Description unavailable

Results from crest-stage gauges installed in burned and unburned colluvial hollows after a low severity file in the southern Appalachians indicate that runoff increases in the year after a wildfire. Two years later, colluvial hollow discharge is similar between burned and unburned sites indicating a return to the initial state. We interpret the increased runoff after the fire to be the result of increased hydrophobicity and decreased soil moisture storage capacity in burned A and AB horizons.

Connectivity of post-fire runoff and sediment from nested hillslopes and watersheds

  • First Published: 13 November 2020
Description unavailable

Low intensity rainfall led to: (1) limited hillslope-to-stream connectivity; and (2) channel incision at most locations. High intensity rainfall led to increased hillslope-channel connectivity and in-stream deposition. Unconfined channels reduced hillslope-to-stream connectivity during high intensity rainfall. During both rain storms, high burn severity increased hillslope-to-stream connectivity and cross-sectional channel change.

An analytical solution for rapidly predicting post-fire peak streamflow for small watersheds in southern California

  • First Published: 13 November 2020
Description unavailable

Rowe et al. (1949), a common method for predicting post-fire peak streamflow, is critically reviewed and analyzed for 33 small watersheds in southern California. This method is found to be insensitive to a variety of spatially and temporally variant morphological and climactic characteristics. An analytical solution is proposed using machine learning to characterize response using a collection of derived parameters.

Factors affecting connectivity and sediment yields following wildfire and post-fire salvage logging in California's Sierra Nevada

  • First Published: 20 November 2020
Description unavailable

  • Following the 2013 Rim Fire and subsequent salvage logging, no significant difference in sediment yield or rill density was found between logged and unlogged small catchments.
  • Rill density was highly correlated to initial sediment yields, and yields were also positively correlated with exposed bare soil extent.
  • Rill density within logged catchments increased with skid trail extent, and exposed bare soil patches were frequently connected by rills to the drainage network.

Compaction and cover effects on runoff and erosion in post-fire salvage logged areas in the Valley Fire, California

  • First Published: 30 November 2020
Description unavailable

We used rainfall simulations to assess the effects of soil compaction by post-fire logging and the effects of ground cover with logging slash on runoff, soil moisture, rainsplash, sediment yield, Ks and Ki modelling parameters. While soil compaction increased both the hydrologic and erosion responses, the slash cover significantly reduced the erosion response. Logging slash was an effective method for mitigating the high erodibility of burned and skid-compacted soils, which are often associated with post-fire land management.

RESEARCH AND OBSERVATORY CATCHMENTS: THE LEGACY AND THE FUTURES

Water quality data for Fall Creek, New York, USA: 1972–1995

  • First Published: 10 November 2020
Description unavailable

The 33,086 ha mixed land use Fall Creek watershed in upstate New York, USA, is part of the Great Lakes drainage system. Results from more than 3,500 water samples are freely available in a data set that compiles flow data and measurements of various water quality analytes collected between 1972 and 1995 in all seasons and under all flow regimes in Fall Creek and its tributaries.

RESEARCH AND OBSERVATORY CATCHMENTS: THE LEGACY AND THE FUTURE

Hydrometeorological dataset (2014–2019) from the high Arctic unglaciated catchment Fuglebekken (Svalbard)

  • First Published: 12 November 2020
Description unavailable

A unique data set from the High Arctic experimental unglaciated catchment Fuglebekken (SW Spitsbergen) is presented. The time series encompasses air temperature, precipitation, wind speed, relative humidity, and runoff from 2014 to 2019. It may serve as the input to rainfall-runoff hydrological models, and allows multi-model parameter estimation and validation. It may also be used in studies on the functioning of Arctic ecosystems.

Watershed studies at the Hubbard Brook Experimental Forest: Building on a long legacy of research with new approaches and sources of data

  • First Published: 20 December 2020
Description unavailable

The Hubbard Brook Experimental Forest was established in 1955 as a major center for hydrologic research in the northeastern US. Since that time, the scope of study has expanded to a collaborative, multidisciplinary research program that includes long-term investigations of air, water, soils, plants, and animals. New lines of research continue to improve understanding of watershed response to disturbance to better inform land management decisions and policies.

ENVIRONMENTAL FLOW MECHANISM AND MANAGEMENT FOR RIVER-LAKE-MARSH SYSTEMS

Optimizing environmental flow and macrophyte management for restoring a large eutrophic lake-marsh system

  • First Published: 04 November 2020
Description unavailable

A combined environmental flow and macrophyte management strategy is optimized for eutrophic lake-marsh system restoration, which accounts for interactions between hydrological processes and key processes associated with nutrient removal, that is, macrophyte growth and bio-denitrification. Macrophyte management balances transpiration-driven water loss and nutrient uptake. Combined environmental flow and macrophyte management significantly improves water quality.

Quantitative analysis of the driving factors for groundwater resource changes in arid irrigated areas

  • First Published: 07 November 2020
Description unavailable

The effects of these three factors on groundwater levels are about 5, 12.5 and 82.5%. And caused the regional average groundwater level to fall by a maximum of 0.07, 0.23, 1.79 m. And the effects of these three factors on the interaction between surface water and groundwater were 7.04, 3.63 and 89.33%, respectively.

A biodiversity evaluation framework for restoration of aquatic macrophyte communities in shallow lakes driven by hydrological process management

  • First Published: 19 November 2020
Description unavailable

Hydrological processes in a shallow lake's marshy wetlands were evaluated based on water level regimes, and a water level regime suitable for macrophyte restoration was proposed based on a multidimensional biodiversity evaluation framework.

WATER AGE AND HYDROLOGICAL PROCESSES

On the relations between the hydrological dynamical systems of water budget, travel time, response time and tracer concentrations

  • First Published: 11 December 2020
Description unavailable

In this paper we discuss various aspects of the water budget and its relationship with travel times, response times, and solute/tracer concentrations. It is a useful summary and reorganization of the concepts and variables presented in the recent literature. It presents material, otherwise spread out over various papers, in a systematic way. It shows how to obtain the probability distributions under scrutiny and, finally, that these have a form derived from the composition of various elementary distributions.

WOMEN ADVANCING RESEARCH IN HYDROLOGICAL PROCESSES

The resilience of logjams to floods

  • First Published: 10 November 2020
Description unavailable

Key findings: Repeat surveys of hundreds of channel-spanning logjams in the US Southern Rocky Mountains indicate that logjams are not randomly distributed at the scale of entire creeks but are randomly distributed within stream reaches delineated based on consistent valley geometry. Wide, low gradient stream reaches with multi-thread channel planform contain greater numbers of logjams than steep, narrowly confined reaches and these patterns persisted through a major rainfall flood. The results reflect the resilience of logjam longitudinal distributions to disturbance.

Open Access

Fingerprinting hydrological and biogeochemical drivers of freshwater quality

  • First Published: 12 November 2020
Description unavailable

Mining high-frequency hydrochemical datasets allows fingerprinting drivers of freshwater quality including the interplay between hydrological and biogeochemical processes. Storm event magnitude and timing controls the type of mobilisation, flushing and cycling behaviour of solutes and particulates. There is a large variation in storm event flushing and cycling but parameters can be grouped into flushing dominated (phosphorus and turbidity), cycling dominated (dissolved oxygen, redox potential and water temperature) and of mixed type (nitrate nitrogen, specific conductivity and pH).

WOMAN ADVANCING RESEARCH IN HYDROLOGICAL PROCESSES

Visualization and ecohydrologic models: Opening the box

  • First Published: 24 November 2020
Description unavailable

How can we increase the usefulness of ecohydrologic models through better visualization that supports learning and new discovery? We present four complementary approaches, that range from simple best practices to novel software engineering and human-computer interface design. Our goal is to open the ecohydrologic model box and engage multiple audiences, from novices to model developers.

Open Access

Stable isotopes of water reveal differences in plant – soil water relationships across northern environments

  • First Published: 23 December 2020
Description unavailable

We compared stable isotopes of water in plant stem (xylem) water and soil collected over a complete growing season from five well-known long-term study sites in northern/cold regions. Xylem water was isotopically depleted compared to soil waters, most notably for deuterium. At all sites except one, water sources of angiosperms could be associated with soil water, while the sources of water uptake by gymnosperms were much less easily explained.

IMPACTS OF OBSERVATIONAL UNCERTAINTY ON ANALYSIS AND MODELLING OF HYDROLOGICAL PROCESSES

RESEARCH ARTICLES

The effect of density-driven flow on the transport of high-concentration solutes in the hyporheic zone

  • First Published: 21 October 2020
Description unavailable

Density gradients induced by high solute concentration can change the flow of pore water. The strong density-driven flow can lead to an unstable flow and cause the appearance of solute fingers.

Direct and indirect effects of rainfall and vegetation coverage on runoff, soil loss, and nutrient loss in a semi-humid climate

  • First Published: 20 November 2020
Description unavailable

We identified the direct and indirect relationships among the influencing factors of soil nutrient loss on runoff plots and constructed a structural diagram of these relationships.

The role of landscape morphology on soil moisture variability in semi-arid ecosystems

  • First Published: 25 November 2020
Description unavailable

Landform shapes modulate soil moisture variability. Fluvial dominated landscapes promote soil moisture variability. Incoming radiation and precipitation variability promote soil moisture variability.

A parameter allocation approach for flow simulation using the WetSpa-Python model

  • First Published: 24 November 2020
Description unavailable

For physics-based modelling of discharge and associated hydrological processes in a watershed, calibration of most parameters can be avoided by utilizing a priori knowledge from field observations and rational or logically based specifications. The Python-WetSpa model was applied to a mountainous watershed in Iran with calibration adjustment of only two parameters. Straightforward and uncomplicated methods were proposed for allocating model parameters. The paper serves as a case study of the modelling framework philosophy advocating understanding over numerical optimization.

Effects of bedrock groundwater discharge on spatial variability of dissolved carbon, nitrogen, and phosphorous concentrations in stream water within a forest headwater catchment

  • First Published: 26 November 2020
Description unavailable

Relationships between the bedrock groundwater contribution in stream water and DOC, DIN and DIP concentrations. The grey and white circles indicate stream water in September and in December 2013, respectively. The solid triangles show the average concentrations of groundwater in soil layer observed at a 0.02 km2 of forested hillslope, and bedrock springs observed in multi points in a 5 km2 catchment, and the vertical error bars with them indicate the SD of them. The horizontal error bars represent the SD for bedrock groundwater contribution. Solid lines indicate regression lines for the results, which are shown only for significant relationships at a significant level of 5%.

Impact of cascade reservoirs on continuity of river water temperature: A temperature trend hypothesis in river

  • First Published: 26 November 2020
Description unavailable

  • Water temperature changes continuously and uniformly in the longitudinal direction of the free-flowing river.
  • River water temperature continuity evaluation are proposed.
  • Mixed reservoirs have no effect on the continuity of river water temperature. In contrast, stratified reservoirs have a great effect on the continuity of river water temperature.
  • The water residence time of the reservoir dominates the continuity of the water temperature in the cascade reservoir.

Spatial and temporal distributions of stable isotopes in precipitation over Thailand

  • First Published: 26 November 2020
Description unavailable

Thailand meteoric water line is established using ordinary and precipitation weighted methods. Spatial δ18O distribution is affected by precipitation patterns and moisture sources. Temporal δ18O distribution in each climate zone is unique due to the different climate conditions.

Predicting quantiles of water quality from catchment characteristics

  • First Published: 28 November 2020
Description unavailable

Statistical models were developed to predict concentration quantiles for sediments, nutrients and salt at 102 sites. Model explained 37%–96% spatial variation. Temperature cropping area and river channel slope are most common predictors for spatial variation of quantiles.

Climate change and other trends in streamflow observations in Australian forested catchments since 1970

  • First Published: 04 December 2020
Description unavailable

Trend analysis of stream flow data is complex as climate variability and other factors need to be removed. This work demonstrates multiple methods and a significant length of time series and fairly homogeneous catchments to identify climate change effects. We identify amplification of declining rainfall trends in the streamflow, but the biophysical origin of this amplification is unclear.

Predicting high-frequency variation in stream solute concentrations with water quality sensors and machine learning

  • First Published: 03 December 2020
Description unavailable

Although new sensors have provided novel information about the fine-scale temporal variation of some streamwater solutes, we lack adequate sensor technology to gain the same insights for many other solutes. We used two machine learning algorithms to predict concentrations at 15-min resolution for a suite of solutes that lack specific sensors. The results showed great promise for using a combined approach of stream sensing and intensive stream discrete sampling to build information about the high-frequency variation of solutes.

Water quality and spatio-temporal hot spots in an effluent-dominated urban river

  • First Published: 03 December 2020
Description unavailable

Water quality in urban systems can be influenced by the river's flow regime and by anthropogenic inputs from industrial or wastewater effluent and runoff from impervious surfaces. In this study, we aimed to determine whether water quality was controlled primarily by wastewater discharge in an effluent-dominated river. We found that although wastewater effluent influenced water quality, spatio-temporal hot spots were also associated with non-point source pollution. Furthermore, hot spots were only evident during periods of low flow in the river.

Stable isotope dynamics of groundwater interactions with Ganges river

  • First Published: 09 December 2020
Description unavailable

Temporally and spatially variable river baseflow quantification and differential interaction of river water and groundwater is evaluated through mixing model using high-resolution stable isotope signatures of water. This hydrological exchange pattern varies depending on river morphometry. The results from this model helped in understanding multi-scale hydrodynamics, hydro-chemical response and aquifer vulnerability for a growing population on a prolific fluvial aquifer system.

Tree water deficit and dynamic source water partitioning

  • First Published: 09 December 2020
Description unavailable

The stable isotopes have shed light on patterns of tree water use in time and space. However, there are several limiting factors to this methodology and the use of isotopes alone has not been enough to provide a mechanistic understanding of tree water use. Here, we show that observed shifts in water uptake can be explained by changes in tree water status. We show that combining physiological measurements with traditional isotope tracing can reveal mechanistic insights into plant water use.

Open Access

Impact assessment of reservoir operation in the context of climate change adaptation in the Chao Phraya River basin

  • First Published: 12 December 2020
Description unavailable

In the Chao Phraya River basin, the future high flow changes due to climate change are larger than those achieved by the reservoir operation (existing and construction under planning) even though the operation increases the basin low flow considerably. Further, a combination of reservoir operation and afforestation was considered as the adaptation strategy in the basin by which the magnitude of discharge reduction in the wet season was still smaller than the increase caused by warming.

Open Access

A field, laboratory, and literature review evaluation of the water retention curve of volcanic ash soils: How well do standard laboratory methods reflect field conditions?

  • First Published: 15 December 2020
Description unavailable

Standard laboratory methods resemble only a small portion of the wet range the Andosols' WRC, but overestimate substantially their water content for higher matric potentials as compared to field conditions. The discrepancy occurs irrespective of site-specific characteristics and the laboratory method applied. This disagreement limits the capacity to infer correctly subsurface hydrological behavior and imply that results reported in past research should be used with caution in decision-making. Ways forward to determine accurately the Andosols' WRC are outlined.

Open Access

Woody buffer effects on water temperature: The role of spatial configuration and daily temperature fluctuations

  • First Published: 13 December 2020
Description unavailable

  • We studied the effect of shading on daily maximum water temperature Tmax in streams.
  • Tmax was reduced by up to −4.6°C, reached equilibrium conditions after ~0.4 km (~45 min travel-time), and was more strongly affected by woody vegetation in a 10 m compared to a 30 m buffer.
  • The effect increased with daily water temperature range Trange, which in turn depended on cloudiness, upstream canopy cover and summer month, indicating that effects are largest in small shallow streams with high Trange.

Regional crop water use assessment using Landsat-derived evapotranspiration

  • First Published: 18 December 2020
Description unavailable

  • Landsat-based field-scale actual evapotranspiration (ETa) maps were generated using the SSEBop model across the state of South Dakota (SD), USA for the 1986-2018 period.
  • Estimated ETa products were further used to understand the crop water-use characteristics and existing historic mono-directional (increasing/decreasing) trends over the eastern (subhumid/cropland dominated) and western (semiarid/shrubland dominated) regions of SD.
  • The study demonstrates the tremendous potential and robustness of the SSEBop model, Landsat imagery, and remote sensing-based ETa modeling approaches in estimating consistent spatially distributed evapotranspiration.

Isotopic fractionation induced by a surface effect influences the estimation of the hydrological process of topsoil

  • First Published: 24 January 2021
Description unavailable

Organic matter content in soil was a key factor determining the isotopic inhomogeneity of soil water. Excluding the surface effect induced by organic matter may improve the application of δ18O and δ2H in hydrological study on soil.

Significance of isotopic and geochemical methods to determine the evolution of inland brackish and bitter water: An example from the Zuli river in the upper reaches of the Yellow River, China

  • First Published: 23 December 2020
Description unavailable

This graphical abstract is mainly describing the main geochemistry evolution processes in the Zuli river catchment. From the source area to the downstream area, fresh groundwater formed in the Huajialing Mountains gradually evolve to saline water. The dissolution of evaporates is shown to be the main source of salinity in brackish water, which also greatly affects the strontium isotopic composition of water. This includes the dissolution of Mg-rich minerals, which is the main cause of the bitterness. The inflow of brackish groundwater is the source of river water in the upper reach. Then evaporation further aggravates the salinization of river water, with water quality evolving to saline conditions in the lower reach. When the river reaches the valley plain, the 87Sr/86Sr ratios decreases significantly, which is primarily related to soil erosion of the riverbanks during runoff.

SCIENTIFIC BRIEFING

A soil moisture monitoring network to assess controls on runoff generation during atmospheric river events

  • First Published: 03 December 2020
Description unavailable

We present a publicly available, high-resolution soil moisture dataset from Russian River Basin in California designed to assess soil moisture controls on runoff generation under atmospheric river conditions. Analyses of the results demonstrate that: (1) Multi-depth sensors are valuable for identifying which depths show differences in evapotranspiration and soil saturation dynamics, (2) Understanding the factors influencing event runoff ratio during a precipitation event enables us to design evaluation techniques and indicates soil moisture processes that distributed hydrologic models should replicate.

RESEARCH ARTICLES

Role of sediment in solute acquisition in the Himalayan glacier meltwater stream, Gangotri glacier, Uttarakhand, India

  • First Published: 21 December 2020
Description unavailable

  • Significant difference observed between Gangotri glacier meltwater chemistry with that of Alpine glacier system. Alpine system is dominated CO2 dissolution while Gangotri system is dominated by sulphide oxidation.
  • Highest SO42− 1095 μeq/L in meltwater of Gangotri glacier was in comparable with that from experiment clearly indicating the role of sediment in the meltwater chemistry.
  • Continuum of high p(CO2) closed system conditions in proglacial stream of Gangotri Glacier also confirmed by the dissolution experiment.