Water Well Hydrographs: An Underutilized Resource for Characterizing Subsurface Conditions

Abstract

Many of the world's major aquifers are under severe stress as a result of intensive pumping to support irrigated agriculture and provide drinking water supplies for millions. The question of what the future holds for these aquifers is one of global importance. Without better information about subsurface conditions, it will be difficult to reliably assess an aquifer's response to management actions and climatic stresses. One important but underutilized source of information is the data from monitoring well networks that provide near-continuous records of water levels through time. Most organizations running these networks are, by necessity, primarily focused on network maintenance. The result is that relatively little attention is given to interpretation of the acquired hydrographs. However, embedded in those hydrographs is valuable information about subsurface conditions and aquifer responses to natural and anthropogenic stresses. We demonstrate the range of insights that can be gleaned from such hydrographs using data from the High Plains aquifer index well network of the Kansas Geological Survey. We show how information about an aquifer's hydraulic state and lateral extent, the nature of recharge, the hydraulic connection to the aquifer and nearby pumping wells, and the expected response to conservation-based pumping reductions can be extracted from these hydrographs. The value of this information is dependent on accurate water-level measurements; errors in those measurements can make it difficult to fully exploit the insights that water-well hydrographs can provide. We therefore conclude by presenting measures that can help reduce the potential for such errors.

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Estimation of Specific Yield for Regional Groundwater Models: Pitfalls, Ramifications, and a Promising Path Forward

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Eine Echtzeit-Online-Methode zur Beurteilung der künstlichen Grundwasseranreicherung und Grundwasserentnahme

“…Grundwasserleiter sind heterogen (Cirpka und Valocchi 2016;Sudicky 1986), und daher weisen Messungen des Grundwasserspiegels eine Variabilität auf, die dem Grad der Heterogenität entspricht. Daher besteht einer der Gründe für die Installation mehrerer Grundwassermessstellen darin, genügend Informationen zu erhalten, um mit dieser räumlichen Komplexität angemessen umgehen zu können (Butler et al 2021;Rau et al 2020). Dies kann durch die Untersuchung kleinräumiger Gradientenvariationen, die Verwendung von mindestens drei Brunnenelementen zur Erzeugung von Gradientenfeldern oder durch die Bestimmung ei-nes einzigen, großräumigen Gradienten für den Standort geschehen.…”