Snow drought reduces water transit times in headwater streams

2021 ◽  
Author(s):  
Catalina Segura
Keyword(s):  
Headwater Streams ◽  
Transit Times

scholarly journals Transit times from rainfall to baseflow in headwater catchments estimated using tritium: the Ovens River, Australia

2015 ◽  
Vol 19 (9) ◽  
pp. 3771-3785 ◽  
Author(s):  
I. Cartwright ◽  
U. Morgenstern
Keyword(s):  
Transit Time ◽  
Headwater Streams ◽  
Stream Water ◽  
Mean Transit Time ◽  
Significant Proportion ◽  
Low Flow ◽  
Flow Conditions ◽  
Headwater Catchments ◽  
Flow Models ◽  
Transit Times

Abstract. Headwater streams contribute a significant proportion of the total flow to many river systems, especially during summer low-flow periods. However, despite their importance, the time taken for water to travel through headwater catchments and into the streams (the transit time) is poorly understood. Here, 3H activities of stream water are used to define transit times of water contributing to streams from the upper reaches of the Ovens River in south-east Australia at varying flow conditions. 3H activities of the stream water varied from 1.63 to 2.45 TU, which are below the average 3H activity of modern local rainfall (2.85 to 2.99 TU). The highest 3H activities were recorded following higher winter flows and the lowest 3H activities were recorded at summer low-flow conditions. Variations of major ion concentrations and 3H activities with streamflow imply that different stores of water from within the catchment (e.g. from the soil or regolith) are mobilised during rainfall events rather than there being simple dilution of an older groundwater component by event water. Mean transit times calculated using an exponential-piston flow model range from 4 to 30 years and are higher at summer low-flow conditions. Mean transit times calculated using other flow models (e.g. exponential flow or dispersion) are similar. There are broad correlations between 3H activities and the percentage of rainfall exported from each catchment and between 3H activities and Na and Cl concentrations that allow first-order estimates of mean transit times in adjacent catchments or at different times in these catchments to be made. Water from the upper Ovens River has similar mean transit times to the headwater streams implying there is no significant input of old water from the alluvial gravels. The observation that the water contributing to the headwater streams in the Ovens catchment has a mean transit time of years to decades implies that these streams are buffered against rainfall variations on timescales of a few years. However, impacts of any changes to land use in these catchments may take years to decades to manifest themselves in changes to streamflow or water quality.

Using geochemistry to understand water sources and transit times in headwater streams of a temperate rainforest

2018 ◽  
Vol 99 ◽  
pp. 1-12 ◽  
Author(s):  
Ian Cartwright ◽  
Alexander P. Atkinson ◽  
Benjamin S. Gilfedder ◽  
Harald Hofmann ◽  
Dioni I. Cendón ◽  
...  
Keyword(s):  
Headwater Streams ◽  
Water Sources ◽  
Temperate Rainforest ◽  
Transit Times

scholarly journals Transit times from rainfall to baseflow in headwater catchments estimated using tritium: the Ovens River, Australia

2015 ◽  
Vol 12 (6) ◽  
pp. 5427-5463 ◽  
Author(s):  
I. Cartwright ◽  
U. Morgenstern
Keyword(s):  
Transit Time ◽  
Headwater Streams ◽  
Stream Water ◽  
Mean Transit Time ◽  
Significant Proportion ◽  
Low Flow ◽  
Flow Conditions ◽  
Headwater Catchments ◽  
Flow Models ◽  
Transit Times

Abstract. Headwater streams contribute a significant proportion of the total flow to many river systems, especially during summer low-flow periods. However, despite their importance, the time taken for water to travel through headwater catchments and into the streams (the transit time) is poorly constrained. Here, 3H activities of stream water are used to define transit times of water contributing to streams from the upper reaches of the Ovens River in southeast Australia at varying flow conditions. 3H activities of the stream water varied from 1.63 to 2.45 TU, which are below the average 3H activity of modern local rainfall (~3 TU). The highest 3H activities were recorded following higher winter flows and the lowest 3H activities were recorded at summer low-flow conditions. Variations of major ion concentrations and 3H activities with streamflow imply that different stores of water from within the catchment (e.g. from the soil or regolith) are mobilised during rainfall events rather than there being simple dilution of an older groundwater component by event water. Mean transit times calculated using an exponential-piston flow model range between 5 and 31 years and are higher at summer low-flow conditions. Mean transit times calculated using other flow models (e.g. exponential flow or dispersion) are similar. There are broad correlations between 3H activities and the percentage of rainfall exported from each catchment and between 3H activities and Na and Cl concentrations that allow first-order estimates of mean transit times in adjacent catchments or at different times in these catchments to be made. Water from the upper Ovens River has similar mean transit times to the headwater streams implying there is no significant input of old water from the alluvial gravels. The observation that the water contributing to the headwater streams in the Ovens catchment has a mean transit time of years to decades implies that these streams are buffered against rainfall variations on timescales of a few years. However, impacts of any changes to landuse in these catchments may take years to decades to manifest itself in changes to streamflow or water quality.

Intercontinental and transcontinental mail transit times from Europe to Berkeley, 1892 to 1941

1986 ◽  
Vol 13 (2) ◽  
pp. 141-154 ◽  
Author(s):  
RUDOLF SCHMID
Keyword(s):  
Transit Times ◽  
In Transit

SUMMARY Mail transit times from Germany to Berkeley, California, are computed for issues of the current awareness journals Botanisches Centralblatt (1880–1945) and the interdisciplinary Naturae Novitates (1879–1944). Issues of the former for 1892 to 1902 averaged 29.3 days (31.2 days if abnormal times are included) in transit from Kassel to Berkeley, with many issues (92) requiring only 20 to 25 days for intercontinental and transcontinental transit. Mail transit of Naturae Novitates from Berlin to Berkeley averaged 40.7 days (42 if abnormal times are included) per issue for 1903 to 1916 and 44 days (51.1 days) per issue for 1922 to 1941 (cumulatively averaging 42 days, or 45.9 days for abnormal times), with some issues in 1906 requiring only 11-12 days for intercontinental and transcontinental transit. A smaller sampling for Nature for 1923 and 1930 gave averages of, respectively, 21.5 and 22.4 days, with a minimum of 14 days in both years. These times are consistent with known transatlantic and transcontinental, ship and rail, mail transit times for these periods, as tabulated from various sources. For perspective, early intercontinental and transcontinental air transit times and pre-1892 intercontinental ship transit times are also tabulated.

Hydrogeological responses in tropical mountainous springs

2019 ◽  
Author(s):  
Ricardo Sánchez-Murillo
Keyword(s):  
Costa Rica ◽  
Isotope Composition ◽  
Central Valley ◽  
Distribution Functions ◽  
Geochemical Composition ◽  
Transit Times ◽  
Management Plans ◽  
Best Fit ◽  
Term Data

This study presents a hydrogeochemical analysis of spring responses (2013-2017) in the tropical mountainous region of the Central Valley of Costa Rica. The isotopic distribution of δ18O and δ2H in rainfall resulted in a highly significant meteoric water line: δ2H = 7.93×δ18O + 10.37 (r2=0.97). Rainfall isotope composition exhibited a strong dependent seasonality. The isotopic variation (δ18O) of two springs within the Barva aquifer was simulated using the FlowPC program to determine mean transit times (MTTs). Exponential-piston and dispersion distribution functions provided the best-fit to the observed isotopic composition at Flores and Sacramento springs, respectively. MTTs corresponded to 1.23±0.03 (Sacramento) and 1.42±0.04 (Flores) years. The greater MTT was represented by a homogeneous geochemical composition at Flores, whereas the smaller MTT at Sacramento is reflected in a more variable geochemical response. The results may be used to enhance modelling efforts in central Costa Rica, whereby scarcity of long-term data limits water resources management plans.

FLASHINESS OF HEADWATER STREAMS WITHIN THE CONTEXT OF SEASONAL CHANGES IN EVAPOTRANSPIRATION AND DIFFERING LAND USE

2018 ◽  
Author(s):  
Peter Whitehouse ◽  
◽  
Heather Mase ◽  
Forrest Parrott ◽  
Chris Paradise ◽  
...  
Keyword(s):  
Land Use ◽  
Seasonal Changes ◽  
Headwater Streams

scholarly journals MOST Spacebased Photometry of HD 189733: Precise Timing Measurements for Transits Across an Active Star

2008 ◽  
Vol 4 (S253) ◽  
pp. 459-461
Author(s):  
E. Miller-Ricci ◽  
J. F. Rowe ◽  
D. Sasselov ◽  
J. M. Matthews ◽  
R. Kuschnig ◽  
...  
Keyword(s):  
Orbital Period ◽  
Mass Range ◽  
Active Star ◽  
Precise Timing ◽  
Resonant Orbits ◽  
The Earth ◽  
Test Spot ◽  
Transit Times ◽  
Nearly Continuous ◽  
Parent Star

AbstractWe have measured transit times for HD 189733 passing in front of its bright (V = 7.67) chromospherically active and spotted parent star. Nearly continuous broadband photometry of this system was obtained with the MOST (Microvariability & Oscillations of STars) space telesope during 21 days in August 2006, monitoring 10 consecutive transits. We have used these data to search for deviations from a constant orbital period which can indicate the presence of additional planets in the system that are as yet undetected by Doppler searches. We find no variations above the level of ±45 s, ruling out planets in the Earth-to-Neptune mass range in a number of resonant orbits. We find that a number of complications can arise in measuring transit times for a planet transiting an active star with large star spots. However, such transiting systems are also useful in that they can help to constrain and test spot models. This has implications for the large number of transiting systems expected to be discovered by the CoRoT and Kepler missions.

Catchment topography and the distribution of electron donors for denitrification control the nitrate concentration in headwater streams of the Lake Hachiro watershed

2020 ◽  
pp. 1-13
Author(s):  
Atsushi Hayakawa ◽  
Yu Funaki ◽  
Tatsuya Sudo ◽  
Ryoki Asano ◽  
Hirotatsu Murano ◽  
...  
Keyword(s):  
Headwater Streams ◽  
Nitrate Concentration ◽  
Electron Donors

Influence of leaf miners and environmental quality on litter breakdown in tropical headwater streams

Hydrobiologia ◽  
2021 ◽  
Vol 848 (6) ◽  
pp. 1311-1331
Author(s):  
Vivian de Mello Cionek ◽  
Fábio Nascimento Oliveira Fogaça ◽  
Timothy Peter Moulton ◽  
Laryssa Helena Ribeiro Pazianoto ◽  
Guilherme Okuda Landgraf ◽  
...  
Keyword(s):  
Environmental Quality ◽  
Headwater Streams ◽  
Litter Breakdown ◽  
Leaf Miners
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