scholarly journals Stormwater harvesting in ephemeral streams: how to bypass clogging and unsaturated layers

2021 ◽  
Author(s):  
José D. Henao Casas ◽  
Fritz Kalwa ◽  
Marc Walther ◽  
Randolf Rausch
Keyword(s):  
Vadose Zone ◽  
Numerical Models ◽  
Water Storage ◽  
Sensitivity Analyses ◽  
Ephemeral Streams ◽  
Infiltration Rates ◽  
Stormwater Harvesting ◽  
Harvesting Systems ◽  
Study Case ◽  
Recharge Rates

AbstractTo cope with water scarcity in drylands, stormwater is often collected in surface basins and subsequently stored in shallow aquifers via infiltration. These stormwater harvesting systems are often accompanied by high evaporation rates and hygiene problems. This is commonly a consequence of low infiltration rates, which are caused by clogging layers that form on top of the soil profile and the presence of a thick vadose zone. The present study aims to develop a conceptual solution to increase groundwater recharge rates in stormwater harvesting systems. The efficiency of vadose-zone wells and infiltration trenches is tested using analytical equations, numerical models, and sensitivity analyses. Dams built in the channel of ephemeral streams (wadis) are selected as a study case to construct the numerical simulations. The modelling demonstrated that vadose-zone wells and infiltration trenches contribute to effective bypassing of the clogging layer. By implementing these solutions, recharge begins 2250–8100% faster than via infiltration from the bed surface of the wadi reservoir. The sensitivity analysis showed that the recharge rates are especially responsive to well length and trench depth. In terms of recharge quantity, the well had the best performance; it can infiltrate up to 1642% more water than the reservoir, and between 336 and 825% more than the trench. Moreover, the well can yield the highest cumulative recharge per dollar and high recharge rates when there are limitations to the available area. The methods investigated here significantly increased recharge rates, providing practical solutions to enhance aquifer water storage in drylands.

scholarly journals Vulnerability assessment and potential contamination of unconfined aquifers

2018 ◽  
Vol 19 (4) ◽  
pp. 1008-1016 ◽  
Author(s):  
J. Caprario ◽  
A. S. Rech ◽  
A. R. Finotti
Keyword(s):  
Vadose Zone ◽  
Vulnerability Index ◽  
The Other ◽  
Sensitivity Analyses ◽  
Drastic Model ◽  
Groundwater Availability ◽  
Unconfined Aquifers ◽  
Direct Infiltration ◽  
The Subject ◽  
The Impact

Abstract The decline in groundwater availability and quality has become a worldwide issue and has been the subject of several studies in recent decades. In this sense, the goal of this study is to assess the vulnerability of the Campeche Aquifer (Florianopolis, Brazil), identifying potential areas of possible contamination by the direct infiltration of runoff in drainage compensatory techniques. To achieve this goal, the following methodological steps were used: (1) data collection and preparation, (2) application of the DRASTIC model, (3) sensitivity analysis and (4) analysis of potential contamination by compensatory techniques. The results show that approximately 33% of the aquifer area presented moderate vulnerability to contamination. However, 29% of the remaining areas had high and extremely high vulnerability. Analysing the potential of contamination with drainage compensatory structures we verified that approximately 95% of them are located in areas of vulnerability classified as moderate and high. The other 5% were identified in areas with extremely high vulnerability. Sensitivity analyses indicated that the removal of topography, soil type and the impact of the vadose zone caused a large variation in vulnerability index. It is evident that there is a high potential of contamination of groundwater by direct infiltration of drainage compensatory structures.

Renewed thinking on groundwater age

2021 ◽  
Author(s):  
Grant Ferguson ◽  
Mark Cuthbert ◽  
Kevin Befus ◽  
Tom Gleeson ◽  
Chandler Noyes ◽  
...  
Keyword(s):  
Environmental Flows ◽  
Numerical Models ◽  
Groundwater Age ◽  
Holistic Approach ◽  
Water Levels ◽  
Residence Times ◽  
Groundwater Sustainability ◽  
Long Time ◽  
Mean Residence Times ◽  
Recharge Rates

<p>Groundwater age and mean residence times have been invoked as measures of groundwater sustainability, with the idea that old or "fossil" groundwater is non-renewable. This idea appears to come from the link between groundwater age and background recharge rates, which are also of questionable use in assessing the sustainability of groundwater withdrawals. The use of groundwater age to assess renewability is further complicated by its relationship with flow system geometry. Young groundwaters near recharge areas are not inherently more renewable than older groundwaters down gradient. Similarly, there is no reason to preferentially use groundwater from smaller aquifers, which will have smaller mean residence times than larger aquifers for the same recharge rate. In some cases, groundwater ages may provide some information where groundwater recharge rates were much higher in the past and systems are no longer being recharged. However, there are few examples where the relationship between depletion and changes in recharge over long time periods has been rigorously explored. Groundwater age measurements can provide insights into the functioning of groundwater flow systems and calibration targets for numerical models and we advocate for their continued use, but they are not a metric of sustainable development. Simple metrics to assess groundwater sustainability remain elusive and a more holistic approach is warranted to maintain water levels and environmental flows.</p>

scholarly journals Impact of Soil Amendments on the Hydraulic Conductivity of Boreal Agricultural Podzols

Agriculture ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 133 ◽  
Author(s):  
Dinushika Wanniarachchi ◽  
Mumtaz Cheema ◽  
Raymond Thomas ◽  
Vanessa Kavanagh ◽  
Lakshman Galagedara
Keyword(s):  
Hydraulic Conductivity ◽  
Vadose Zone ◽  
Hydraulic Properties ◽  
Soil Amendments ◽  
Dairy Manure ◽  
Soil Hydrology ◽  
Inorganic N ◽  
Infiltration Rates ◽  
Agricultural Setting ◽  
Properties Of Soil

Hydraulic properties of soil are the basis for understanding the flow and transport through the vadose zone. It has been demonstrated that different soil amendments can alter the soil properties affecting soil hydrology. The aim of this study was to determine the effect of soil amendments on hydraulic conductivity (K) of a loamy sand podzolic soil under both unsaturated (Kunsat) and near-saturated (near Ksat) conditions in an agricultural setting. A field experiment was conducted with two common soil amendments: Dairy manure (DM) in 2016 and 2017 and biochar (BC) once only in 2016. DM and BC were incorporated up to a depth of 0.15–0.20 m at a rate of 30,000 L ha−1 and 20 Mg ha−1, respectively. A randomized complete block experimental design was used and the plots planted with silage corn (Zea mays L.) without irrigation. The treatments were: Control without amendment (0N), inorganic N fertilizer (IN), two types of DM (IN+DM1 and IN+DM2), and two treatments with BC (IN+BC and IN+DM1+BC). Infiltration data were collected using a mini disk infiltrometer under three tension levels in which −0.04 and −0.02 m was ascribed as unsaturated (at the wet end) and −0.001 m as near-saturated condition. Based on the measured infiltration rates, Kunsat and near Ksat hydraulic conductivities were calculated. There were no significant effects of DM and BC on bulk density and near Ksat. Treatments IN+DM1, IN+DM2, and IN+DM1+BC significantly reduced the Kunsat compared to the control. Since these soil amendments can influence soil hydrology such as reduced infiltration and increased surface runoff, carefully monitored application of soil amendments is recommended.

Modelling the seasonal dynamics of the soil water balance of vineyards

2003 ◽  
Vol 30 (6) ◽  
pp. 699 ◽  
Author(s):  
Eric Lebon ◽  
Vincent Dumas ◽  
Philippe Pieri ◽  
Hans R. Schultz
Keyword(s):  
Water Balance ◽  
Soil Water ◽  
Soil Layer ◽  
Water Storage ◽  
Soil Evaporation ◽  
Water Dynamics ◽  
Soil Water Balance ◽  
Sensitivity Analyses ◽  
Rooting Depth ◽  
Top Soil

A geometrical canopy model describing radiation absorption (Riou et al. 1989, Agronomie 9, 441–450) and partitioning between grapevines (Vitis vinifera L.) and soil was coupled to a soil water balance routine describing a bilinear change in relative transpiration rate as a function of the fraction of soil transpirable water (FTSW). The model was amended to account for changes in soil evaporation after precipitation events and subsequent dry-down of the top soil layer. It was tested on two experimental vineyards in the Alsace region, France, varying in soil type, water-holding capacity and rooting depth. Simulations were run over four seasons (1992–1993, 1995–1996) and compared with measurements of FTSW conducted with a neutron probe. For three out of four years, the model simulated the dynamics in seasonal soil water balance adequately. For the 1996 season soil water content was overestimated for one vineyard and underestimated for the other. Sensitivity analyses revealed that the model responded strongly to changes in canopy parameters, and that soil evaporation was particularly sensitive to water storage of the top soil layer after rainfall. We found a close relationship between field-average soil water storage and pre-dawn water potential, a relationship which could be used to couple physiological models of growth and / or photosynthesis to the soil water dynamics.

A spatial covariance model for GRACE and GRACE-FO terrestrial water storage data

2020 ◽  
Author(s):  
Maik Thomas ◽  
Eva Boergens ◽  
Henryk Dobslaw ◽  
Robert Dill ◽  
Christoph Dahle ◽  
...  
Keyword(s):  
Bessel Function ◽  
Numerical Models ◽  
Water Storage ◽  
Terrestrial Water Storage ◽  
Covariance Model ◽  
Spatial Covariance ◽  
Spatial Error ◽  
Grace Data ◽  
Uncertainty Estimates ◽  
Terrestrial Water

<p>Gridded terrestrial water storage (TWS) observed by GRACE or GRACE-FO typically show a spatial error structure that is anisotropic (direction depending), non-homogeneous (latitude depending), and non-stationary (time depending).</p><p>We will introduce a new covariance model characterizing this error behavior analytically with a direction depending Bessel function of the first kind. The anisotropy of this function is governed by a shape parameter allowing for longer correlation lengths in longitudinal than in latitudinal direction. The wave-effect of the Bessel function allows us to account for the residuals of the GRACE striping errors. Both size as well as shape parameters of the Bessel function vary smoothly with latitude. These variations are implemented via even Legendre polynomials. The non-stationarity of the covariance is modeled with time-varying point variances. The validity of this covariance model on the sphere was thoroughly tested with a Monte-Carlo approach.</p><p>First, we apply this covariance model to 5 years of simulated GRACE data (Flechtner et al., 2016) where true errors are readily available from the differences of the synthetic input and the finally recovered gravity fields. For the 50 largest discharge basins, we obtain more realistic time series uncertainties than from propagating the formal errors associated with the Stokes coefficients. For smaller basins, however, the covariance model tends to provide overly pessimistic uncertainty estimates.</p><p>Second, the model is adapted to real GRACE and GRACE-FO data to obtain realistic error covariance information for arbitrarily shaped basins from globally gridded error information. We will show the current plans to update GFZ’s GravIS portal (http://gravis.gfz-potsdam.de/home) so that area- and time-dependent error information which is critically important for the assimilation of GRACE-based TWS data into numerical models will become readily available to the user community.</p>

scholarly journals Creative computing with Landlab: an open-source toolkit for building, coupling, and exploring two-dimensional numerical models of Earth-surface dynamics

2017 ◽  
Vol 5 (1) ◽  
pp. 21-46 ◽  
Author(s):  
Daniel E. J. Hobley ◽  
Jordan M. Adams ◽  
Sai Siddhartha Nudurupati ◽  
Eric W. H. Hutton ◽  
Nicole M. Gasparini ◽  
...  
Keyword(s):  
Open Source ◽  
Numerical Models ◽  
Epistemic Uncertainty ◽  
Process Models ◽  
Third Party ◽  
Sensitivity Analyses ◽  
Surface Dynamics ◽  
New Process ◽  
Creative Computing ◽  
Classroom Use

Abstract. The ability to model surface processes and to couple them to both subsurface and atmospheric regimes has proven invaluable to research in the Earth and planetary sciences. However, creating a new model typically demands a very large investment of time, and modifying an existing model to address a new problem typically means the new work is constrained to its detriment by model adaptations for a different problem. Landlab is an open-source software framework explicitly designed to accelerate the development of new process models by providing (1) a set of tools and existing grid structures – including both regular and irregular grids – to make it faster and easier to develop new process components, or numerical implementations of physical processes; (2) a suite of stable, modular, and interoperable process components that can be combined to create an integrated model; and (3) a set of tools for data input, output, manipulation, and visualization. A set of example models built with these components is also provided. Landlab's structure makes it ideal not only for fully developed modelling applications but also for model prototyping and classroom use. Because of its modular nature, it can also act as a platform for model intercomparison and epistemic uncertainty and sensitivity analyses. Landlab exposes a standardized model interoperability interface, and is able to couple to third-party models and software. Landlab also offers tools to allow the creation of cellular automata, and allows native coupling of such models to more traditional continuous differential equation-based modules. We illustrate the principles of component coupling in Landlab using a model of landform evolution, a cellular ecohydrologic model, and a flood-wave routing model.

scholarly journals Supplemental Material: Sustainable densification of the deep crust

2020 ◽  
Author(s):  
Benjamin Malvoisin
Keyword(s):  
Numerical Models ◽  
Bulk Composition ◽  
Coupling Reaction ◽  
Reaction Model ◽  
Diffusion Reaction ◽  
Sensitivity Analyses ◽  
Plagioclase Composition ◽  
Deep Crust ◽  
Inclusion Mapping ◽  
Reaction Fluid

Materials and methods, Figures S1–S9 (fluid-inclusion mapping and point analyses of garnet and clinopyroxene with FTIR, sensitivity analyses for the two numerical models, results of the diffusion-reaction model in open system conditions, X-ray mapping of amphibole inclusions in clinopyroxene, evolution in space of the plagioclase composition), Tables S1 and S2 (chemical composition of the main minerals, and local bulk composition used for numerical modelling), and Movies S1 and S2 (results in 2-D of the model coupling reaction, fluid flow, and deformation).<br>

scholarly journals Creative computing with Landlab: an open-source toolkit for building, coupling, and exploring two-dimensional numerical models of Earth-surface dynamics

2016 ◽  
Author(s):  
Daniel E. J. Hobley ◽  
Jordan M. Adams ◽  
Sai Siddhartha Nudurupati ◽  
Eric W. H. Hutton ◽  
Nicole M. Gasparini ◽  
...  
Keyword(s):  
Open Source ◽  
Numerical Models ◽  
Epistemic Uncertainty ◽  
Process Models ◽  
Third Party ◽  
Sensitivity Analyses ◽  
Surface Dynamics ◽  
New Process ◽  
Creative Computing ◽  
Classroom Use

Abstract. The ability to model surface processes and to couple them to both subsurface and atmospheric regimes has proven invaluable to research in the Earth and planetary sciences. However, creating a new model typically demands a very large investment of time, and modifying an existing model to address a new problem typically means the new work is constrained to its detriment by model adaptations for a different problem. Landlab is an open-source software framework explicitly designed to accelerate the development of new process models by providing: (1) a set of tools and existing grid structures – including both regular and irregular grids – to make it faster and easier to develop new process components, or numerical implementations of physical processes; (2) a suite of stable, modular, and interoperable process components that can be combined to create an integrated model; and (3) a set of tools for data input, output, manipulation, and visualization. A set of example models built with these components is also provided. Landlab's structure makes it ideal not only for fully developed modelling applications, but also for model prototyping and classroom use. Because of its modular nature, it can also act as a platform for model intercomparison and epistemic uncertainty and sensitivity analyses. Landlab exposes a standardized model interoperability interface, and is able to couple to third party models and software. Landlab also offers tools to allow the creation of cellular automata, and allows native coupling of such models to more traditional continuous differential equation-based modules. We illustrate the principles of component coupling in Landlab using a model of landform evolution, a cellular ecohydrologic model, and a flood-wave routing model.

scholarly journals Supplemental Material: Sustainable densification of the deep crust

2020 ◽  
Author(s):  
Benjamin Malvoisin
Keyword(s):  
Numerical Models ◽  
Bulk Composition ◽  
Coupling Reaction ◽  
Reaction Model ◽  
Diffusion Reaction ◽  
Sensitivity Analyses ◽  
Plagioclase Composition ◽  
Deep Crust ◽  
Inclusion Mapping ◽  
Reaction Fluid

Materials and methods, Figures S1–S9 (fluid-inclusion mapping and point analyses of garnet and clinopyroxene with FTIR, sensitivity analyses for the two numerical models, results of the diffusion-reaction model in open system conditions, X-ray mapping of amphibole inclusions in clinopyroxene, evolution in space of the plagioclase composition), Tables S1 and S2 (chemical composition of the main minerals, and local bulk composition used for numerical modelling), and Movies S1 and S2 (results in 2-D of the model coupling reaction, fluid flow, and deformation).<br>

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