Evaluating the use of diurnal groundwater fluctuations for estimating evapotranspiration in wetland environments: case studies in southeast England and northeast Germany

Mould, D. J.; Frahm, Enrico; Salzmann, Thomas; Miegel, Konrad; Acreman, Mike

doi:10.1002/eco.108

Cited by 42 publications

(33 citation statements)

References 25 publications

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“…

{ET}_{g} = ([], ((), H_{1} - L) + \frac{H_{2} - L}{T_{2}} \times T_{1}) \times S_{y},

where S y is the specific yield of the groundwater fluctuation aquifer, H 1 is the groundwater level in early morning (mm) of the study day, H 2 is the groundwater level in early morning of the following day (mm), L is the lowest point of groundwater depth hydrograph on the target day (m), T 1 is the number of hours of the drawdown period, from H 1 to L (hr), and T 2 is the number of hours of the rising period, from L to H 2 (hr). This method separates the time periods of WTD descending and recovery, partitioning the diurnal hydrograph into two constituent parts of T 1 and T 2 (Mould, Frahm, Salzmann, Miegel, & Acreman, ). This method is adopted in this study.…”

Section: Methodsmentioning

confidence: 99%

Drip irrigation enhances shallow groundwater contribution to crop water consumption in an arid area

Wang

Huo

Guan

et al. 2018

Hydrological Processes

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Shallow groundwater plays a key role in agro‐hydrological processes of arid areas. Groundwater often supplies a necessary part of the water requirement of crops and surrounding native vegetation, such as groundwater‐dependent ecosystems. However, the impact of water‐saving irrigation on cropland water balance, such as the contribution of shallow groundwater to field evapotranspiration, requires further investigation. Increased understanding of quantitative evaluation of field‐scale water productivity under different irrigation methods aids policy and decision‐making. In this study, high‐resolution water table depth and soil water content in field maize were monitored under conditions of flood irrigation (FI) and drip irrigation (DI), respectively. Groundwater evapotranspiration (ETg) was estimated by the combination of the water table fluctuation method and an empirical groundwater–soil–atmosphere continuum model. The results indicate that daily ETg at different growth stages varies under the two irrigation methods. Between two consecutive irrigation events of the FI site, daily ETg rate increases from zero to greater than that of the DI site. Maize under DI steadily consumes more groundwater than FI, accounting for 16.4% and 14.5% of ETa, respectively. Overall, FI recharges groundwater, whereas DI extracts water from shallow groundwater. The yield under DI increases compared with that under FI, with less ETa (526 mm) compared with FI (578 mm), and irrigation water productivity improves from 3.51 kg m−3 (FI) to 4.58 kg m−3 (DI) through reducing deep drainage and soil evaporation by DI. These results highlight the critical role of irrigation method and groundwater on crop water consumption and productivity. This study provides important information to aid the development of agricultural irrigation schemes in arid areas with shallow groundwater.

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“…

{ET}_{g} = ([], ((), H_{1} - L) + \frac{H_{2} - L}{T_{2}} \times T_{1}) \times S_{y},

Section: Methodsmentioning

confidence: 99%

Drip irrigation enhances shallow groundwater contribution to crop water consumption in an arid area

Wang

Huo

Guan

et al. 2018

Hydrological Processes

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“…S y is of crucial importance because errors in S y estimation directly translate to the ET g estimates (Loheide et al ., ; Lautz, ; Mould et al ., ; Cheng et al ., ). However, there are many difficulties in estimating S y because this parameter is not constant with time; it depends upon the water table depth and the soil hydraulic properties.…”

Section: Introductionmentioning

confidence: 97%

Performance of the White method for estimating groundwater evapotranspiration under conditions of deep and fluctuating groundwater

et al. 2015

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Abstract:The White method is a simple but the most frequently applied approach to estimate groundwater evapotranspiration (ET g ) from groundwater level diurnal signals. Because of a lack of direct measurements of ET g , it is difficult to evaluate the performance of the White method, particularly in field environments with variable groundwater fluctuations. A 2-year field observation in a hyper-arid riparian tamarisk (Tamarix spp.) stand with deep groundwater depth in the lower Tarim River basin of China was conducted to measure the surface evapotranspiration (ET s ) and groundwater table. The performance of the White method and the influences of the variable groundwater fluctuations on the determinations of the specific yield (S y ) and recharge rate of groundwater (r) in the White method were investigated. The results showed that the readily available S y determined by Loheide's method was feasible but must be finely determined based on the soil textures in the layers in which the groundwater level fluctuated. A constant S y value for a defined porous medium could be assumed regardless of the discharge or recharge processes of groundwater. The time span of 0000 h to 0600 h for r estimation for the White method worked best than other time spans. A 2-day moving average of r values further enhance ET g estimation. Slight effects of environmental or anthropogenic disturbances on the diurnal fluctuations of groundwater level did not influence the ET g estimations by the White method. Our results provide valuable references to the application of the White method for estimating daily ET g in desert riparian forests with deep groundwater depth.

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“…Note that the monthly and weekly sample 349 rates do not pick up the rainfall events and that sub-daily (in this case hourly) 350 sampling is needed to detect the diurnal pattern. Monitoring at a suitably high 351 temporal resolution can allow estimation of evaporative loss (e.g., Gilman 1994; 352 Mould et al 2010) during periods of zero rainfall, when lateral flow is constant and 353 evaporative loss is enough to drive a diurnal oscillation in water levels (assuming 354 constant lateral or upward shallow groundwater flow). However producing unnec-355 essarily large datasets can be problematic when information storage and analysis are 356 considered.…”

Section: Au5mentioning

confidence: 99%

Hydrological Assessment and Monitoring of Wetlands

Low¹,

Farr

Clarke

et al. 2018

The Wetland Book

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Evaluating the use of diurnal groundwater fluctuations for estimating evapotranspiration in wetland environments: case studies in southeast England and northeast Germany

Cited by 42 publications

References 25 publications

Drip irrigation enhances shallow groundwater contribution to crop water consumption in an arid area

Drip irrigation enhances shallow groundwater contribution to crop water consumption in an arid area

Performance of the White method for estimating groundwater evapotranspiration under conditions of deep and fluctuating groundwater

Hydrological Assessment and Monitoring of Wetlands

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