The exponential decline in saturated hydraulic conductivity with depth: a novel method for exploring its effect on water flow paths and transit time distribution

2016 ◽  
Vol 30 (14) ◽  
pp. 2438-2450 ◽  
Author(s):  
A. A. Ameli ◽  
J. J. McDonnell ◽  
K. Bishop
Keyword(s):  
Hydraulic Conductivity ◽  
Water Flow ◽  
Transit Time ◽  
Time Distribution ◽  
Saturated Hydraulic Conductivity ◽  
Flow Paths ◽  
Exponential Decline ◽  
Novel Method ◽  
Transit Time Distribution ◽  
Water Flow Paths

Hillslope permeability architecture controls on subsurface transit time distribution and flow paths

2016 ◽  
Vol 543 ◽  
pp. 17-30 ◽  
Author(s):  
A.A. Ameli ◽  
N. Amvrosiadi ◽  
T. Grabs ◽  
H. Laudon ◽  
I.F. Creed ◽  
...  
Keyword(s):  
Transit Time ◽  
Time Distribution ◽  
Flow Paths ◽  
Transit Time Distribution

scholarly journals The Wavelets show it – the transit time of water varies in time

2018 ◽  
Vol 66 (3) ◽  
pp. 295-302 ◽  
Author(s):  
Milan Onderka ◽  
Vladimír Chudoba
Keyword(s):  
Transit Time ◽  
Time Distribution ◽  
Conceptual Modeling ◽  
Flow Paths ◽  
Transit Times ◽  
The Mean ◽  
Transit Time Distribution ◽  
Mathematical Techniques ◽  
Time Invariant

Abstract The ways how water from rain or melting snow flows over and beneath the Earth‘s surface affects the timing and intensity at which the same water leaves a catchment. Several mathematical techniques have been proposed to quantify the transit times of water by e.g. convolving the input-output tracer signals, or constructing frequency response functions. The primary assumption of these techniques is that the transit time is regarded time-invariant, i.e. it does not vary with temporarily changing e.g. soil saturation, evaporation, storage volume, climate or land use. This raises questions about how the variability of water transit time can be detected, visualized and analyzed. In this paper we present a case study to show that the transit time is a temporarily dynamic variable. Using a real-world example from the Lower Hafren catchment, Wales, UK, and applying the Continuous Wavelet Transform we show that the transit time distributions are time-variant and change with streamflow. We define the Instantaneous Transit Time Distributions as a basis for the Master Transit Time Distribution. We show that during periods of elevated runoff the transit times are exponentially distributed. A bell-shaped distribution of travel times was observed during times of lower runoff. This finding is consistent with previous investigations based on mechanistic and conceptual modeling in the study area according to which the diversity of water flow-paths during wet periods is attributable to contributing areas that shrink and expand depending on the duration of rainfall. The presented approach makes no assumptions about the shape of the transit time distribution. The mean travel time estimated from the Master Transit Time Distribution was ~54.3 weeks.

Water flow paths are hotspots for the dissemination of antibiotic resistance in soil

Chemosphere ◽  
2018 ◽  
Vol 193 ◽  
pp. 1198-1206 ◽  
Author(s):  
K. Lüneberg ◽  
B. Prado ◽  
M. Broszat ◽  
P. Dalkmann ◽  
D. Díaz ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Water Flow ◽  
Flow Paths ◽  
Water Flow Paths

The master transit time distribution of variable flow systems

2012 ◽  
Vol 48 (6) ◽  
Author(s):  
Ingo Heidbüchel ◽  
Peter A. Troch ◽  
Steve W. Lyon ◽  
Markus Weiler
Keyword(s):  
Transit Time ◽  
Time Distribution ◽  
Variable Flow ◽  
Flow Systems ◽  
Transit Time Distribution

scholarly journals On the use of spring baseflow recession for a more accurate parameterization of aquifer transit time distribution functions

2013 ◽  
Vol 17 (5) ◽  
pp. 1825-1831 ◽  
Author(s):  
J. Farlin ◽  
P. Maloszewski
Keyword(s):  
Transit Time ◽  
Time Distribution ◽  
Mean Transit Time ◽  
Distribution Functions ◽  
Rate Of Change ◽  
Spring Discharge ◽  
Atrazine Concentration ◽  
Groundwater Dating ◽  
Transit Time Distribution ◽  
Trend Reversal

Abstract. Baseflow recession analysis and groundwater dating have up to now developed as two distinct branches of hydrogeology and have been used to solve entirely different problems. We show that by combining two classical models, namely the Boussinesq equation describing spring baseflow recession, and the exponential piston-flow model used in groundwater dating studies, the parameters describing the transit time distribution of an aquifer can be in some cases estimated to a far more accurate degree than with the latter alone. Under the assumption that the aquifer basis is sub-horizontal, the mean transit time of water in the saturated zone can be estimated from spring baseflow recession. This provides an independent estimate of groundwater transit time that can refine those obtained from tritium measurements. The approach is illustrated in a case study predicting atrazine concentration trend in a series of springs draining the fractured-rock aquifer known as the Luxembourg Sandstone. A transport model calibrated on tritium measurements alone predicted different times to trend reversal following the nationwide ban on atrazine in 2005 with different rates of decrease. For some of the springs, the actual time of trend reversal and the rate of change agreed extremely well with the model calibrated using both tritium measurements and the recession of spring discharge during the dry season. The agreement between predicted and observed values was however poorer for the springs displaying the most gentle recessions, possibly indicating a stronger influence of continuous groundwater recharge during the summer months.

Plant communities along preferential superficial water flow paths across a floodplain landscape

Ecohydrology ◽  
2019 ◽  
Vol 12 (6) ◽  
Author(s):  
Ilda Entraigas ◽  
Natalia Vercelli ◽  
Luisa Fajardo
Keyword(s):  
Water Flow ◽  
Plant Communities ◽  
Flow Paths ◽  
Water Flow Paths
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