scholarly journals Hierarchical climate-driven dynamics of the active channel length in temporary streams

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Gianluca Botter ◽  
Filippo Vingiani ◽  
Alfonso Senatore ◽  
Carrie Jensen ◽  
Markus Weiler ◽  
...  
Keyword(s):  
Temporal Variations ◽  
Channel Length ◽  
Mathematical Framework ◽  
Stream Length ◽  
Temporary Streams ◽  
Temporary Stream ◽  
Discontinuous Flow ◽  
Hierarchical Structuring ◽  
Average Fraction ◽  
Active Channel

AbstractLooking across a landscape, river networks appear deceptively static. However, flowing streams expand and contract following ever-changing hydrological conditions of the surrounding environment. Despite the ecological and biogeochemical value of rivers with discontinuous flow, deciphering the temporary nature of streams and quantifying their extent remains challenging. Using a unique observational dataset spanning diverse geomorphoclimatic settings, we demonstrate the existence of a general hierarchical structuring of river network dynamics. Specifically, temporary stream activation follows a fixed and repeatable sequence, in which the least persistent sections activate only when the most persistent ones are already flowing. This hierarchical phenomenon not only facilitates monitoring activities, but enables the development of a general mathematical framework that elucidates how climate drives temporal variations in the active stream length. As the climate gets drier, the average fraction of the flowing network decreases while its relative variability increases. Our study provides a novel conceptual basis for characterizing temporary streams and quantifying their ecological and biogeochemical impacts.

Characterizing temporary stream dynamics: the Stream Length Duration Curve

2021 ◽  
Author(s):  
Nicola Durighetto ◽  
Anfonso Senatore ◽  
Gianluca Botter
Keyword(s):  
Network Dynamics ◽  
Catchment Scale ◽  
Stream Length ◽  
Temporary Streams ◽  
Active Length ◽  
Temporary Stream ◽  
Riverine Ecosystems ◽  
Objective Classification ◽  
Event Based

<p>Temporary streams (i.e. streams that temporarily cease to flow) are becoming a hot research topic in hydrology. These streams provide an invaluable contribution to riverine ecosystems, as they host a variety of habitats (from lotic to lentic and terrestrial) which sustain high biodiversity. Temporary streams can be found in different regions of the world and are characterized by strongly heterogeneous flow patterns, from flashy streams that flow only after rainfall events to rivers that episodically experience droughts. Many recent studies investigated temporary streams, originating interesting observational datasets about event-based or seasonal network dynamics. Empirical or conceptual models are usually employed for assessing the main physical drivers of network dynamics in each specific study site.<br>In this contribution, we develop and apply novel theoretical tools to understand how the local statistical properties of each reach of the network affect the catchment-scale variability of the active length. In particular, the Stream Length Duration Curve (SLDC) is proposed to efficiently summarize catchment-scale dynamics of the active length, providing an objective way to quantify network dynamics. The concept of SLDC is applied to a number of Italian headwater catchments, where data about temporal changes in the configuration of the flowing stream are available, providing a clue for the characterization of emergent temporal and spatial patterns of network dynamics. The Stream Length Duration Curve can facilitate comparisons across different catchments an time periods, possibly enabling and objective classification of temporary streams. </p>

scholarly journals Islands of the upper River Ob: morphometric characteristic, evolution and dynamics

2019 ◽  
pp. 80-90 ◽  
Author(s):  
G. B. Golubtsov ◽  
R. S. Chalov
Keyword(s):  
Channel Length ◽  
Morphological Aspect ◽  
Channel Stability ◽  
Channel Deformations ◽  
River Islands ◽  
Lateral Channel ◽  
Empirical Relations ◽  
Active Channel ◽  
Channel Type

The studied reach of the upper River Ob is quite complicated in the morphological aspect and characterized by very low channel stability and high discharge of sand load. Unconstrained conditions for lateral channel migration promotes active channel deformations not only at long-term scale, but also seasonally. Channel deformations contribute to the transformation of the channel and its morphodynamic type in time. The upper River Ob is intensively used as a water course, so any reorganization of the channel and river islands should be taken into account to support navigation. Morphometric and morphodynamic analysis of the islands made it possible to develop their morphological classification. Morphometric parameters of islands, being associated with the characteristics of the channel itself, are one of the main classification features. Empirical relations were obtained that link the dimensions (Lo, Bo) and shape of islands (Lo/Bo) with the morphodynamic channel type and its stability, the degree of branching of the channel (number of islands no per 1 km of channel length x). The features of island dynamics are also determined by the morphodynamic type of the channel and are associated with the morphometric characteristics of the islands themselves and their position in the channel, which determines the transgressive, regressive and transverse shift or their stable position in time.

Observations on the life history and burrow construction of the crayfish Cambarus fodiens (Cottle) in a temporary stream in southern Ontario

1974 ◽  
Vol 52 (3) ◽  
pp. 365-370 ◽  
Author(s):  
D. Dudley Williams ◽  
N. E. Williams ◽  
H. B. N. Hynes
Keyword(s):  
Life History ◽  
Life Cycle ◽  
Sampling Methods ◽  
Groundwater Table ◽  
Drainage Ditches ◽  
Running Water ◽  
Southern Ontario ◽  
Temporary Streams ◽  
Temporary Stream ◽  
Two Stages

Cambarus fodiens, usually considered an inhabitant of ponds and drainage ditches, is shown to be able to complete its life cycle in a temporary running-water habitat. Details of its life history are given. Sampling methods for burrowing crayfishes are briefly reviewed and a new method is described. The typical burrow construction of this species is shown to be modified at two stages in the life cycle, once in the ovigerous females, and again in the newly released juveniles. It is possible that other inhabitants of temporary streams use these crayfish burrows as refuges when the groundwater table rereats.

Analysis of Hydrogen Passivation Mechanisms in Poly-Si TFT’s by Employing R.F. Plasma

1995 ◽  
Vol 378 ◽  
Author(s):  
K. Y. Choi ◽  
Y. S. Kim ◽  
H.S. Choi ◽  
B.S. Bae ◽  
M. K. Han
Keyword(s):  
Hydrogen Diffusion ◽  
Gate Oxide ◽  
Channel Length ◽  
State Density ◽  
Hydrogen Atoms ◽  
Tail State ◽  
Oxide Tft ◽  
Hydrogenation Time ◽  
Thin Gate Oxide ◽  
Active Channel

AbstractThe dominant pathways for hydrogen diffusion in poly-Si TFT’s are identified by analyzing the hydrogenation effect on the various device geometries. It is observed that the gate poly-Si thickness and channel width didn’t affect the hydrogenation. As the channel length was decreased down to 3 µm, threshold voltage was reduced and field effect mobility was increased significantly with hydrogeantion time. In the thick gate oxide (2000 Å, 4000 Å) poly-Si TFT’s, the device characteristics have been improved rapidly with hydrogenation time. The tail state density of thin gate oxide TFT wasn’t change by hydrgenation while that of thick gate oxide TFT was significantly reduced. Our experimental results may support the model that hydrogen atoms diffuse into the bulk of the active channel layer through the gate oxide and passivate the grain boundary and intragranular defects limitedly by gate oxide area.

Parameter Fluctuations in Multiple Patterned Deca-nm Scaled CMOS Structures

2012 ◽  
Vol 17 ◽  
pp. 157-163 ◽  
Author(s):  
Klaus T. Kallis ◽  
John T. Horstmann ◽  
H.L. Fiedler
Keyword(s):  
Statistical Analysis ◽  
Threshold Voltage ◽  
Channel Length ◽  
Cmos Circuits ◽  
Process Flow ◽  
Industrial Manufacturing ◽  
Immersion Lithography ◽  
Euv Lithography ◽  
193 Nm ◽  
Active Channel

Multiple Patterning Seems to Be One of the Most Promising Solutions for the Gap between the 193 Nm Immersion Lithography and the 13.5 Nm EUV Lithography for Industrial Manufacturing of Ultra Large Scaled Integrated CMOS Circuits [1]. the Used Techniques in this Paper Lead to an Excellent Homogeneity and Uniformity of the Channel Length and Width which Enables a Fundamental Statistical Analysis of the Electrical Transistor Parameters. the Process Flow Has Been Optimized to Minimize the Active Channel Area and to Achieve a Sufficient Yield for a Trustworthy Statistical Analysis. while the Channel Length Is Defined by a Single Deposition- and Etchback Technique the Active Area Is Defined by a Composition of Multiple Spacers that Lead to a Diffusion Stop Barrier. the Statistical Analysis of these Devices Shows Dramatically Increasing Fluctuations of the Threshold Voltage if the Device Dimensions Are Decreased.

scholarly journals Developing a novel approach to analyse the regimes of temporary streams and their controls on aquatic biota

2011 ◽  
Vol 8 (5) ◽  
pp. 9637-9673 ◽  
Author(s):  
F. Gallart ◽  
N. Prat ◽  
E. M. García-Roger ◽  
J. Latron ◽  
M. Rieradevall ◽  
...  
Keyword(s):  
Visual Analysis ◽  
Water Discharge ◽  
Hydrological Regime ◽  
Ecological Quality ◽  
Macroinvertebrate Communities ◽  
Aquatic Life ◽  
Temporary Streams ◽  
Hydrological Conditions ◽  
Temporary Stream

Abstract. Temporary streams are those water courses that undergo the recurrent cessation of flow or the complete drying of their channel. The biological communities in temporary stream reaches are strongly dependent on the temporal changes of the aquatic habitats determined by the hydrological conditions. The use of the aquatic fauna structural and functional characteristics to assess the ecological quality of a temporary stream reach can not therefore be made without taking into account the controls imposed by the hydrological regime. This paper develops some methods for analysing temporary streams' aquatic regimes, based on the definition of six aquatic states that summarize the sets of mesohabitats occurring on a given reach at a particular moment, depending on the hydrological conditions: flood, riffles, connected, pools, dry and arid. We used the water discharge records from gauging stations or simulations using rainfall-runoff models to infer the temporal patterns of occurrence of these states using the developed aquatic states frequency graph. The visual analysis of this graph is complemented by the development of two metrics based on the permanence of flow and the seasonal predictability of zero flow periods. Finally, a classification of the aquatic regimes of temporary streams in terms of their influence over the development of aquatic life is put forward, defining Permanent, Temporary-pools, Temporary-dry and Episodic regime types. All these methods were tested with data from eight temporary streams around the Mediterranean from MIRAGE project and its application was a precondition to assess the ecological quality of these streams using the current methods prescribed in the European Water Framework Directive for macroinvertebrate communities.

scholarly journals A novel approach to analysing the regimes of temporary streams in relation to their controls on the composition and structure of aquatic biota

2012 ◽  
Vol 16 (9) ◽  
pp. 3165-3182 ◽  
Author(s):  
F. Gallart ◽  
N. Prat ◽  
E. M. García-Roger ◽  
J. Latron ◽  
M. Rieradevall ◽  
...  
Keyword(s):  
Visual Analysis ◽  
Water Discharge ◽  
Hydrological Regime ◽  
Ecological Quality ◽  
Aquatic Life ◽  
Temporary Streams ◽  
Hydrological Conditions ◽  
Temporary Stream ◽  
Novel Approach

Abstract. Temporary streams are those water courses that undergo the recurrent cessation of flow or the complete drying of their channel. The structure and composition of biological communities in temporary stream reaches are strongly dependent on the temporal changes of the aquatic habitats determined by the hydrological conditions. Therefore, the structural and functional characteristics of aquatic fauna to assess the ecological quality of a temporary stream reach cannot be used without taking into account the controls imposed by the hydrological regime. This paper develops methods for analysing temporary streams' aquatic regimes, based on the definition of six aquatic states that summarize the transient sets of mesohabitats occurring on a given reach at a particular moment, depending on the hydrological conditions: Hyperrheic, Eurheic, Oligorheic, Arheic, Hyporheic and Edaphic. When the hydrological conditions lead to a change in the aquatic state, the structure and composition of the aquatic community changes according to the new set of available habitats. We used the water discharge records from gauging stations or simulations with rainfall-runoff models to infer the temporal patterns of occurrence of these states in the Aquatic States Frequency Graph we developed. The visual analysis of this graph is complemented by the development of two metrics which describe the permanence of flow and the seasonal predictability of zero flow periods. Finally, a classification of temporary streams in four aquatic regimes in terms of their influence over the development of aquatic life is updated from the existing classifications, with stream aquatic regimes defined as Permanent, Temporary-pools, Temporary-dry and Episodic. While aquatic regimes describe the long-term overall variability of the hydrological conditions of the river section and have been used for many years by hydrologists and ecologists, aquatic states describe the availability of mesohabitats in given periods that determine the presence of different biotic assemblages. This novel concept links hydrological and ecological conditions in a unique way. All these methods were implemented with data from eight temporary streams around the Mediterranean within the MIRAGE project. Their application was a precondition to assessing the ecological quality of these streams.

Spatiotemporal changes in the hydrological state of temporary streams in a pre-alpine headwater catchment

2020 ◽  
Author(s):  
Rick Assendelft ◽  
Ilja van Meerveld
Keyword(s):  
Monitoring System ◽  
The State ◽  
State Change ◽  
Stream Network ◽  
Spatiotemporal Resolution ◽  
Headwater Catchments ◽  
State Data ◽  
Temporary Streams ◽  
Temporary Stream ◽  
Headwater Catchment

<p>Temporary streams are common in headwater catchments and serve as important ecological and hydrological links between these catchments and downstream perennial rivers. However, our understanding of temporary streams in headwater catchments is limited due to a lack of high spatiotemporal resolution data of the three main hydrological states of these streams: dry streambed, standing water and flowing water. In this study, we used a custom designed multi-sensor monitoring system to collect high spatiotemporal resolution state data of the temporary streams in the 0.12 km<sup>2</sup> upper Studibach catchment, a pre-alpine headwater catchment in Alptal, Switzerland. The monitoring system was installed at 30 locations in the stream network. The state data was used to determine: (1) the temporary stream regime for every monitoring location based on the permanence of each hydrological state, (2) the state change thresholds (antecedent soil moisture, precipitation amount and intensity, and discharge at the outlet) for every monitoring location, and (3) the state change patterns in the stream network during precipitation events. The temporary stream regimes, and the state change thresholds and patterns were compared to topographic, land cover and channel characteristics to determine if these factors can explain the variability in temporary stream dynamics. The results show that there are four different landscape areas with distinctive temporary stream dynamics in the catchment, and that a steep forested section with coarse streambed material often disconnects the flowing parts of the upper and lower stream network.</p>

scholarly journals A Low-Cost, Multi-Sensor System to Monitor Temporary Stream Dynamics in Mountainous Headwater Catchments

Sensors ◽  
2019 ◽  
Vol 19 (21) ◽  
pp. 4645 ◽  
Author(s):  
Rick Assendelft ◽  
H. J. van Meerveld
Keyword(s):  
Monitoring System ◽  
Low Cost ◽  
Flow Sensor ◽  
Sensor System ◽  
Spatiotemporal Resolution ◽  
State Data ◽  
Temporary Streams ◽  
Temporary Stream ◽  
State Changes ◽  
Resolution Data

While temporary streams account for more than half of the global discharge, high spatiotemporal resolution data on the three main hydrological states (dry streambed, standing water, and flowing water) of temporary stream remains sparse. This study presents a low-cost, multi-sensor system to monitor the hydrological state of temporary streams in mountainous headwaters. The monitoring system consists of an Arduino microcontroller board combined with an SD-card data logger shield, and four sensors: an electrical resistance (ER) sensor, temperature sensor, float switch sensor, and flow sensor. The monitoring system was tested in a small mountainous headwater catchment, where it was installed on multiple locations in the stream network, during two field seasons (2016 and 2017). Time-lapse cameras were installed at all monitoring system locations to evaluate the sensor performance. The field tests showed that the monitoring system was power efficient (running for nine months on four AA batteries at a five-minute logging interval) and able to reliably log data (<1% failed data logs). Of the sensors, the ER sensor (99.9% correct state data and 90.9% correctly timed state changes) and flow sensor (99.9% correct state data and 90.5% correctly timed state changes) performed best (2017 performance results). A setup of the monitoring system with these sensors can provide long-term, high spatiotemporal resolution data on the hydrological state of temporary streams, which will help to improve our understanding of the hydrological functioning of these important systems.

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