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University of Arizona (2012)

Estimating Surface Water Presence and Infiltration for Intermittent Streams in the Semi-arid Southwest

Nicholas, Hillary Dianne

Titre : Estimating Surface Water Presence and Infiltration for Intermittent Streams in the Semi-arid Southwest

Auteur : Nicholas, Hillary Dianne

Université de soutenance : The University of Arizona

Grade : Master of Science (MS) 2012

Résumé
Ephemeral streams with spatially and temporally variable flow are important ecological settings in semi-arid desert environments that until now have been poorly characterized. Our quantitative analysis explores how intermittent stream hydrology varies across geomorphic (mountain streams to desert washes) and climatic gradients (150-400 mm precipitation) in Southern Arizona. Stream channels were instrumented for the first time with a co-deployment of vertical profiles of subsurface temperature sensors, and electrical resistance (ER) sensors on the bed surface. HYDRUS 1-D was used to simulate vertical unsaturated flow, and differences along hydrologic, topographic, and climatic gradients were compared. Annual surface water presence varied < 1%-82% of the year, and reach-normalized infiltration water volumes were 20,000-2,500,000 m³/(km y). Surface water presence was correlated with geomorphic gradient, and infiltration volumes were correlated with surface water presence. This sensor co-deployment method has shown that ER sensors alone are necessary to estimate infiltration in semi-arid, poorly-sorted, coarse desert channels.

Mots clés : infiltration ; intermittent ; recharge ; temperature ; Hydrology ; arid ; electrical resistance

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Page publiée le 19 septembre 2012, mise à jour le 5 avril 2019