scholarly journals Riparian forest and permanent groundwater: a key coupling for balancing the hillslope water budget in Sudanian West Africa

2013 ◽  
Vol 10 (5) ◽  
pp. 5643-5686
Author(s):  
A. Richard ◽  
S. Galle ◽  
M. Descloitres ◽  
J. M. Cohard ◽  
J. P. Vandervaere ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Water Balance ◽  
Riparian Forest ◽  
Dry Season ◽  
Groundwater Table ◽  
Riparian Forests ◽  
Actual Evapotranspiration ◽  
Anthropogenic Pressure ◽  
Deep Groundwater ◽  
African Monsoon

Abstract. Forests are thought to play an important role in the regional dynamics of the West African monsoon, through their capacity to extract water from permanent aquifers located deep in the soil and pump it into the atmosphere even during the dry season. This is especially true for riparian forests located at the bottom of the hillslopes. This coupling between the riparian forests and the permanent aquifers is investigated, looking for quantifying its contribution to the catchment water balance. To this end, use is made of the observations available from a comprehensively instrumented hillslope through the framework of the AMMA-CATCH (African Monsoon Multidisciplinary Analysis – Coupling the Tropical Atmosphere and the Hydrological Cycle) observing system. Attention is paid to measurements of actual evapotranspiration, soil moisture and deep groundwater level. A vertical 2-D approach is followed using the physically-based Hydrus 2-D model in order to simulate the hillslope hydrodynamics, the model being calibrated and evaluated through a multi-criteria approach. The model correctly simulates the hydrodynamics of the hillslope as far as soil moisture dynamics, deep groundwater fluctuation and actual evapotranspiration dynamics are concerned. In particular, the model is able to reproduce the observed hydraulic disconnection between the deep permanent groundwater table and the river. A virtual experiment shows that the riparian forest depletes the deep groundwater table level through transpiration occurring throughout the year so that the permanent aquifer and the river are not connected. Moreover the riparian forest and the deep groundwater table form a coupled transpiration system: the riparian forest transpiration is due to the water redistribution at the hillslope scale feeding the deep groundwater through lateral saturated flow. The annual cycle of the transpiration origin is also quantified. The riparian forest which covers only 5% of the hillslope generates 37% of the annual transpiration, this proportion reaching 57% during the dry season. In a region of intense anthropogenic pressure, forest clearing and its replacement by cropping could impact significantly the water balance at catchment scale with a possible feedback on the regional monsoon dynamics.

scholarly journals Interplay of riparian forest and groundwater in the hillslope hydrology of Sudanian West Africa (northern Benin)

2013 ◽  
Vol 17 (12) ◽  
pp. 5079-5096 ◽  
Author(s):  
A. Richard ◽  
S. Galle ◽  
M. Descloitres ◽  
J.-M. Cohard ◽  
J.-P. Vandervaere ◽  
...  
Keyword(s):  
West Africa ◽  
Transpiration Rate ◽  
Riparian Forest ◽  
Dry Season ◽  
Groundwater Table ◽  
Actual Evapotranspiration ◽  
Virtual Experiment ◽  
Deep Groundwater ◽  
Riparian Area ◽  
Study Results

Abstract. Forests are thought to play an important role in the regional dynamics of the West African monsoon, through their capacity to extract water from a permanent and deep groundwater table to the atmosphere even during the dry season. It should be the case for riparian forests too, as these streambank forests are key landscape elements in Sudanian West Africa. The interplay of riparian forest and groundwater in the local hydrodynamics was investigated, by quantifying their contribution to the water balance. Field observations from a comprehensively instrumented hillslope in northern Benin were used. Particular attention was paid to measurements of actual evapotranspiration, soil water and deep groundwater levels. A vertical 2-D hydrological modelling approach using the Hydrus software was used as a testing tool to understand the interactions between the riparian area and the groundwater. The model was calibrated and evaluated using a multi-criteria approach (reference simulation). A virtual experiment, including three other simulations, was designed (no forest, no groundwater, neither forest nor groundwater). The model correctly simulated the hydrodynamics of the hillslope regarding vadose zone dynamics, deep groundwater fluctuation and actual evapotranspiration dynamics. The virtual experiment showed that the riparian forest transpiration depleted the deep groundwater table level and disconnected it from the river, which is consistent with the observations. The riparian forest and the deep groundwater table actually form an interacting transpiration system: the high transpiration rate in the riparian area was shown to be due to the existence of the water table, supplied by downslope lateral water flows within the hillslope soil layer. The simulated riparian transpiration rate was practically steady all year long, around 7.6 mm d−1. This rate lies within high-end values of similar study results. The riparian forest as simulated here contributes to 37% of the annual hillslope transpiration, and reaches 57% in the dry season, whereas it only covers 5% of the hillslope area.

scholarly journals ¿Refleja Formicidae el impacto de la degradación de los bosques ribereños en la Amazonía Oriental?

2019 ◽  
Vol 67 (4) ◽  
Author(s):  
Stefania Pinzon Triana ◽  
Guillaume Xavier Rousseau ◽  
Jhonatan Andrés Muñoz Gutiérrez ◽  
Alexandra Rocha da Piedade ◽  
Heder Braun
Keyword(s):  
Riparian Forest ◽  
Similarity Index ◽  
Canopy Cover ◽  
Dry Season ◽  
Riparian Forests ◽  
Sampling Effort ◽  
Anthropogenic Pressure ◽  
Successional Stage ◽  
Vegetation Height ◽  
The Impact

The increasing anthropogenic pressure on the Eastern Amazon makes the diagnostic of forest degradation imperative, particularly, the effect on key communities within the riparian ecosystems. Formicidae is commonly used in diagnostic and monitoring studies in areas under restoration. This study aimed to determine the impact of riparian forest successional stages (open areas, and, early, intermediate, and advanced succession) on the richness, frequency, and composition of Formicidae. Sampling was performed during both dry and wet seasons, with the TSBF (Tropical Soil Biological and Fertility) method. Collected organisms were identified to species and morphospecies level and the analysis of collector curves determined the method efficiency to represent the ant sub-community. Ant richness and frequency were submitted to generalized linear mixed models to evaluate the effects of season, local, and successional stage. We used linear regressions model to investigate the relationship between richness and frequency of ants with canopy cover and vegetation height. Species composition was represented by the Jaccard similarity index. In total, we observed 1940 individuals grouped into 86 (morpho)species. Analysis of sampling effort suggested that we obtained more than 80% of the probable species richness. Frequency and richness significantly increased following the advanced succession in comparison with the open areas during the dry season. Canopy cover and vegetation height seemed to moderately affect both richness and frequency of Formicidae during the dry season. Intermediate and advanced succession areas presented similar composition with 50 shared species, followed by the areas of early succession with 43, and, anthropic use with 34 shared species. We conclude that the elimination of riparian forests results in a substantial effect on the richness and frequency of Formicidae, with minimum values in open areas during the dry season. Forest areas transformed to agricultural systems suffered losses of 41% and 56% of richness and frequency respectively. Succession restores forest structure and functions thus, favoring re-colonization of ant species. Formicidae reflects forests degradation, and is a key group in monitoring programs for the conservation/restoration of local riparian forests. Agroforestry and silvopastoral systems should be promoted as low impact practices for adjacent lands to riparian forests.

scholarly journals Probabilistic inference of ecohydrological parameters using observations from point to satellite scales

2018 ◽  
Vol 22 (6) ◽  
pp. 3229-3243 ◽  
Author(s):  
Maoya Bassiouni ◽  
Chad W. Higgins ◽  
Christopher J. Still ◽  
Stephen P. Good
Keyword(s):  
Soil Moisture ◽  
Water Balance ◽  
Soil Water ◽  
Dry Season ◽  
Soil Water Balance ◽  
Rainfall Pattern ◽  
Site Specific ◽  
Soil Moisture Dynamics ◽  
Soil Saturation ◽  
Moisture Dynamics

Abstract. Vegetation controls on soil moisture dynamics are challenging to measure and translate into scale- and site-specific ecohydrological parameters for simple soil water balance models. We hypothesize that empirical probability density functions (pdfs) of relative soil moisture or soil saturation encode sufficient information to determine these ecohydrological parameters. Further, these parameters can be estimated through inverse modeling of the analytical equation for soil saturation pdfs, derived from the commonly used stochastic soil water balance framework. We developed a generalizable Bayesian inference framework to estimate ecohydrological parameters consistent with empirical soil saturation pdfs derived from observations at point, footprint, and satellite scales. We applied the inference method to four sites with different land cover and climate assuming (i) an annual rainfall pattern and (ii) a wet season rainfall pattern with a dry season of negligible rainfall. The Nash–Sutcliffe efficiencies of the analytical model's fit to soil observations ranged from 0.89 to 0.99. The coefficient of variation of posterior parameter distributions ranged from < 1 to 15 %. The parameter identifiability was not significantly improved in the more complex seasonal model; however, small differences in parameter values indicate that the annual model may have absorbed dry season dynamics. Parameter estimates were most constrained for scales and locations at which soil water dynamics are more sensitive to the fitted ecohydrological parameters of interest. In these cases, model inversion converged more slowly but ultimately provided better goodness of fit and lower uncertainty. Results were robust using as few as 100 daily observations randomly sampled from the full records, demonstrating the advantage of analyzing soil saturation pdfs instead of time series to estimate ecohydrological parameters from sparse records. Our work combines modeling and empirical approaches in ecohydrology and provides a simple framework to obtain scale- and site-specific analytical descriptions of soil moisture dynamics consistent with soil moisture observations.

Soil water balance and evapotranspiration of irrigated cotton

1967 ◽  
Vol 69 (1) ◽  
pp. 95-101 ◽  
Author(s):  
W. R. Stern
Keyword(s):  
Soil Moisture ◽  
Water Balance ◽  
Soil Water ◽  
Balance Equation ◽  
Dry Season ◽  
Soil Water Balance ◽  
Wet Season ◽  
Water Balance Equation ◽  
Soil Moisture Storage ◽  
Moisture Storage

In a series of five irrigated cotton sowings (T2, T7, T9, T11, T14) evapotranspiration (Et) was determined for the period between October 1961 and October 1962 by observing frequently the changes in soil moisture storage, calculating through drainage, and solving for evapotranspiration in the water balance equation. Thus a water balance was obtained for each sowing extending over the entire crop.The average evapotranspiration in wet season sowings was of the order of 6·5 mm day−1 and in dry season sowings of the order of 4·5 mm day−1. The highest evapotranspiration values ranged between 10 and 12 mm day−1 in T2, T7 and T9 and between 7 and 9·5 mm day−1 in T11 and T14.

Soil moisture dynamics and implications for irrigation of farmland with a deep groundwater table

2017 ◽  
Vol 192 ◽  
pp. 138-148 ◽  
Author(s):  
Xudong Li ◽  
Yong Zhao ◽  
Weihua Xiao ◽  
Mingzhi Yang ◽  
Yanjun Shen ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Groundwater Table ◽  
Deep Groundwater ◽  
Soil Moisture Dynamics ◽  
Moisture Dynamics

scholarly journals The Role of Soil Moisture in the Water-Balance of a Small-Clay Catchment, 1967-75

1985 ◽  
Vol 16 (2) ◽  
pp. 79-88
Author(s):  
R. K. Pegg
Keyword(s):  
Soil Moisture ◽  
Water Balance ◽  
Actual Evapotranspiration ◽  
Groundwater Storage ◽  
Soil Moisture Data

An eight year run of detailed soil moisture data has been incorporated into simple water balance calculations in an attempt to estimate actual evapotranspiration. The value of this data is shown when compared with estimates using only groundwater storage and its role during the autumn is particularly evident.

Water Use by Maize at Three Plant Densities

1971 ◽  
Vol 7 (2) ◽  
pp. 161-169 ◽  
Author(s):  
Lloyd A. Downey
Keyword(s):  
Soil Moisture ◽  
Water Balance ◽  
Water Use ◽  
Root Zone ◽  
Ground Cover ◽  
Grain Filling ◽  
Stress Conditions ◽  
Actual Evapotranspiration ◽  
Deep Drainage ◽  
Plant Densities

SUMMARYWater use by maize at three densities was measured by a complete water balance, including soil moisture, rain, applied irrigation and deep drainage in crops irrigated so that relative turgidity at noon remained above 90 per cent (i.e. no-stress conditions). Total evapotranspiration between planting and harvest, 56 cm., was not significantly affected by density, but evapotranspiration was slightly higher at higher densities when ground cover was less than 50 per cent. Actual evapotranspiration rose to 1 cm. per day during anthesis and grain filling. A fifth of the water applied moved beyond the root zone, indicating that work on more permeable soils would be inaccurate if the deep drainage component was ignored.

The Summer Water Balance in a Danish Oak Stand

1984 ◽  
Vol 15 (4-5) ◽  
pp. 213-222 ◽  
Author(s):  
K. Rømer Rasmussen ◽  
S. Rasmussen
Keyword(s):  
Soil Moisture ◽  
Water Stress ◽  
Water Balance ◽  
Leaf Area ◽  
Saturated Soil ◽  
Actual Evapotranspiration ◽  
Oak Forest ◽  
Noticeable Effect ◽  
The Difference ◽  
Oak Leaves

The summer water balance in a Danish oak forest was studied during a period of 5 years. Interception reduces rainfall inside the forest by about 15%. Variations of the saturated soil moisture amount to some 10% of the water available to plants. Nevertheless, in most summers low soil moisture only restricts evapotranspiration during July. Insufficient leaf area is a major factor in restricting evapotranspiration: oak leaves develop late, and defoliation by insects also has a noticeable effect. The difference between potential and actual evapotranspiration normally ranges between 50 and 100 mm but reached 150 mm in 1976. Yet even in this dry year the vegetation recovered at once as soon as the water stress had been removed.

scholarly journals Assessing Annual Actual Evapotranspiration Based on Climate, Topography and Soil in Natural and Agricultural Ecosystems

Climate ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 20
Author(s):  
Kleoniki Demertzi ◽  
Vassilios Pisinaras ◽  
Emanuel Lekakis ◽  
Evangelos Tziritis ◽  
Konstantinos Babakos ◽  
...  
Keyword(s):  
Water Balance ◽  
Large Scale ◽  
Hydrological Model ◽  
Actual Evapotranspiration ◽  
Irrigated Agriculture ◽  
Climate Data ◽  
Natural Ecosystems ◽  
Loading Effects ◽  
Very High ◽  
Of Greece

Simple formulas for estimating annual actual evapotranspiration (AET) based on annual climate data are widely used in large scale applications. Such formulas do not have distinct compartments related to topography, soil and irrigation, and for this reason may be limited in basins with high slopes, where runoff is the dominant water balance component, and in basins where irrigated agriculture is dominant. Thus, a simplistic method for assessing AET in both natural ecosystems and agricultural systems considering the aforementioned elements is proposed in this study. The method solves AET through water balance based on a set of formulas that estimate runoff and percolation. These formulas are calibrated by the results of the deterministic hydrological model GLEAMS (Groundwater Loading Effects of Agricultural Management Systems) for a reference surface. The proposed methodology is applied to the country of Greece and compared with the widely used climate-based methods of Oldekop, Coutagne and Turk. The results show that the proposed methodology agrees very well with the method of Turk for the lowland regions but presents significant differences in places where runoff is expected to be very high (sloppy areas and areas of high rainfall, especially during December–February), suggesting that the proposed method performs better due to its runoff compartment. The method can also be applied in a single application considering irrigation only for the irrigated lands to more accurately estimate AET in basins with a high percentage of irrigated agriculture.

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