When space is time: evolving soil hydrology on glacial moraines

Featured image: The Stein Glacier in the central Swiss Alps, where the study was conducted. Left panel © Google, right panels CC BY Florian Lustenberger in Hartmann et al. 2020.

Paper: Field observations of soil hydrological flow path evolution over 10 millennia

Authors: Hartmann , A., Semenova, E., Weiler, M., & Blume, T.

The way water flows through soil and sediments can be incredibly diverse. In the simplest case, water flows uniformly through all of the pore space between grains. Most soils act very differently though. Water moves quickly through certain pathways and not at all through other areas. This preferential flow of water has important consequences for the ability of the soil to hold water, and for the movement of nutrients and contaminants. Understanding what factors affect the evolution of preferential flow pathways can help scientists better understand how soils work now, and how they will respond to human induced changes into the future.

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The Extraction of Hidden Waters: 11th century Persian scientist laid the foundations for hydrology and water engineering

Qanat: Aerial View

Featured Image: Areal view of the vertical shafts of a qanat in Jupar, Iran. S.H. Rashedi / CC BY-ND via UNESCO.

Paper: The millennium-old hydrogeology textbook The Extraction of Hidden Waters by the Persian mathematician and engineer Abubakr Mohammad Karaji (953 CE–1029 CE)

Authors: Ataie-Ashtiani, B., & Simmons, C. T.

Reliable sources of water are essential for every civilization. However, the Western science of hydrology is relatively young. It started perhaps at the turn of the 19th century when John Dalton completed the first water balance for England and Wales by estimating the amount of water that fell as precipitation and left as evaporation and flow from rivers to oceans. Since ancient times, civilizations have built water infrastructure like aqueducts and wells, and writings by Aristotle and Plato suggest that the ancient Greeks had a basic understanding of the water cycle. Though in many respects, the study of hydrology in Europe and the Mediterranean stagnated between the time of these early philosophers and the 19th century.

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Thickets and patches: woody plants are changing water availability in dry landscapes

Featured Image: Sparse woody plant encroachment, known as xerification, occurs here in the Chihuahuan Desert north of Coyame, in Chihuahua, Mexico. Source: Ricraider / CC BY-SA via Wikimedia Commons.

Paper: Woody Plant Encroachment has a Larger Impact than Climate Change on Dryland Water Budgets

Authors: A.P. Schreiner-McGraw, E.R. Vivoni, H. Ajami, O.E. Sala, H.L. Throop, and D.P.C. Peters

Almost half of the land on Earth is arid, with little precipitation. Arid lands are home to roughly 20% of the world’s human population, and to much of the world’s livestock as well. Arid lands are changing rapidly, both with respect to land cover and water availability. While the effects of climate change on arid places have attracted a lot of attention, the encroachment of woody plants into grasslands is also rapidly transforming arid landscapes. New research shows that the effects of woody plant encroachment are even more important than climate change for the water budget of arid ecosystems.

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