Title: Effect of temporal averaging of meteorological data on predictions of groundwater recharge

Abstract

Accurate estimates of infiltration and groundwater recharge are critical for many hydrologic, agricultural and environmental applications. Anticipated climate change in many regions of the world, especially in tropical areas, is expected to increase the frequency of high-intensity, short-duration precipitation events, which in turn will affect the groundwater recharge rate. Estimates of recharge are often obtained using monthly or even annually averaged meteorological time series data. In this study we employed the HYDRUS-1D software package to assess the sensitivity of groundwater recharge calculations to using meteorological time series of different temporal resolutions (i.e., hourly, daily, weekly, monthly and yearly averaged precipitation and potential evaporation rates). Calculations were applied to three sites in Brazil having different climatological conditions: a tropical savanna (the Cerrado), a humid subtropical area (the temperate southern part of Brazil), and a very wet tropical area (Amazonia). To simplify our current analysis, we did not consider any land use effects by ignoring root water uptake. Temporal averaging of meteorological data was found to lead to significant bias in predictions of groundwater recharge, with much greater estimated recharge rates in case of very uneven temporal rainfall distributions during the year involving distinct wet and dry seasons. For example, at themore » Cerrado site, using daily averaged data produced recharge rates of up to 9 times greater than using yearly averaged data. In all cases, an increase in the time of averaging of meteorological data led to lower estimates of groundwater recharge, especially at sites having coarse-textured soils. Lastly, our results show that temporal averaging limits the ability of simulations to predict deep penetration of moisture in response to precipitation, so that water remains in the upper part of the vadose zone subject to upward flow and evaporation.« less

Authors:

Batalha, Marcia S. ^[1]; Barbosa, Maria C. ^[1]; Faybishenko, Boris ^[2]; van Genuchten, Martinus Th. ^[3]

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+ Show Author Affiliations

1. Univ. of Rio de Janeiro, Rio de Janeiro (Brazil)
2. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
3. Sao Paulo State Univ., Rio Claro (Brazil); Utrecht Univ., Utrecht (Netherlands)

Publication Date:

Tue Feb 06 00:00:00 EST 2018

Research Org.:

Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Biological and Environmental Research (BER)

OSTI Identifier:

1461160

Grant/Contract Number:  

AC02-05CH11231

Resource Type:

Accepted Manuscript

Journal Name:

Journal of Hydrology and Hydromechanics

Additional Journal Information:

Journal Volume: 66; Journal Issue: 2; Journal ID: ISSN 0042-790X

Publisher:

de Gruyter

Country of Publication:

United States

Language:

English

Subject:

54 ENVIRONMENTAL SCIENCES; Groundwater recharge; Meteorological data; Temporal averaging; HYDRUS-1D; Infiltration; Evaporation