scholarly journals Calcium transfer and mass balance associated with soil carbonate in a semi‐arid silicate watershed (North Cameroon): an overlooked geochemical cascade?

2020 ◽  
Author(s):  
Fabienne Dietrich ◽  
Nathalie Diaz ◽  
Pierre Deschamps ◽  
David Sebag ◽  
Eric P. Verrecchia
Keyword(s):  
Mass Balance ◽  
Soil Carbonate ◽  
Semi Arid

scholarly journals Spatial and temporal variability of groundwater recharge in a sandstone aquifer in a semi-arid region

2018 ◽  
Author(s):  
Ferdinando Manna ◽  
Steven Murray ◽  
Daron Abbey ◽  
Paul Martin ◽  
John Cherry ◽  
...  
Keyword(s):  
Mass Balance ◽  
Groundwater Recharge ◽  
Temporal Variability ◽  
Arid Regions ◽  
Balance Method ◽  
Spatial And Temporal Variability ◽  
Chloride Mass Balance ◽  
Mike She ◽  
Mass Balance Method ◽  
Semi Arid

Abstract. With the aim to understand the spatial and temporal variability of groundwater recharge, a high-resolution, spatially-distributed numerical model (MIKE SHE) representing surface water and groundwater was used to simulate responses to precipitation in a 2.16 km2 upland catchment on fractured sandstone near Los Angeles, California. Exceptionally high temporal and spatial resolution was used for this catchment modeling: an hourly time-step, a 20 × 20 meter grid in the horizontal plane and 240 numerical layers distributed vertically within the thick vadose zone and in the upper part of the groundwater zone. The finest-practical spatial and temporal resolution were selected to accommodate the large degree of surface and subsurface variability of catchment features. Physical property values for the different lithologies were assigned based on previous on-site investigations whereas the parameters controlling streamflow and evapotranspiration were derived from literature information. The calibration of streamflow at the outfall and of transient and average hydraulic head provided confidence in the reasonableness of these input values and in the ability of the model to reproduce observed processes. Confidence in the calibrated model was enhanced by validation through, (i) comparison of simulated average recharge to estimates based on the applications of the chloride mass-balance method from data from the groundwater and vadose zones within and beyond the catchment (Manna et al., 2016; Manna et al., 2017) and, (ii) comparison of the water isotope signature (18O and 2H) in shallow groundwater to the variability of isotope signatures for precipitation events over an annual cycle. The average simulated recharge across the catchment for the period 1995–2014 is 16 mm y−1 (4 % of the average annual precipitation), which is consistent with previous estimates obtained by using the chloride mass balance method (4.2 % of the average precipitation). However, one of the most unexpected results was that local recharge was simulated to vary from 0 to > 1000 mm y−1 due to episodic precipitation and overland runoff effects. This recharge occurs episodically with the major flux events at the bottom of the evapotranspiration zone, as simulated by MIKE SHE and confirmed by the isotope signatures, occurring only at the end of the rainy season. This is the first study that combines MIKE SHE simulations with the analysis of water isotopes in groundwater and rainfall to determine the timing of recharge processes in semi-arid regions. The study advances the understanding of recharge and unsaturated flow processes in semi-arid regions and enhances our ability to predict the effects of surface and subsurface features on recharge rates. This is crucial in highly heterogeneous contaminated sites because different contaminant source areas have widely varying recharge and, hence, groundwater fluxes impacting their mobility.

scholarly journals Rock-Sourced Nitrogen in Semi-Arid, Shale-Derived California Soils

2021 ◽  
Vol 4 ◽  
Author(s):  
Nina L. Bingham ◽  
Eric W. Slessarev ◽  
Peter M. Homyak ◽  
Oliver A. Chadwick
Keyword(s):  
Mass Balance ◽  
Chemical Weathering ◽  
Field Studies ◽  
N Deposition ◽  
Mixing Model ◽  
N Fixation ◽  
Atmospheric N Deposition ◽  
Geochemical Mass Balance ◽  
Semi Arid ◽  
N Flux

Models suggest that rock-derived nitrogen (N) inputs are of global importance to ecosystem N budgets; however, field studies demonstrating the significance of rock N inputs are rare. We examined rock-derived N fluxes in soils derived from sedimentary rocks along a catena formed under a semi-arid climate. Our measurements demonstrate that there are distinct and traceable pools of N in the soil and bedrock and that the fraction of rock-derived N declines downslope along the catena. We used geochemical mass balance weathering flux measurements to estimate a rock-derived N flux of 0.145 to 0.896 kg ha–1 yr–1 at the ridgecrest. We also developed independent N flux estimates using a 15N-based isotope mixing model. While geochemical mass-balance-based estimates fell within the 95% confidence range derived from the isotope mixing model (−1.1 to 44.3 kg ha–1 yr–1), this range was large due to uncertainty in values for atmospheric 15N deposition. Along the catena, N isotopes suggest a diminishing effect of rock-derived N downslope. Overall, we found that despite relatively large N pools within the saprolite and bedrock, slow chemical weathering and landscape denudation limit the influence of rock-derived N, letting atmospheric N deposition (7.1 kg ha–1 yr–1) and N fixation (0.9–3.1 kg ha–1 yr–1) dominate N inputs to this grassland ecosystem.

Linking chloride mass balance infiltration rates with chlorofluorocarbon and SF6groundwater dating in semi-arid settings: potential and limitations

2010 ◽  
Vol 46 (3) ◽  
pp. 312-324 ◽  
Author(s):  
Susanne Stadler ◽  
Karsten Osenbrück ◽  
Wilhelmus H.M. Duijnisveld ◽  
Martin Schwiede ◽  
Jürgen Böttcher
Keyword(s):  
Mass Balance ◽  
Chloride Mass Balance ◽  
Infiltration Rates ◽  
Semi Arid

scholarly journals Identification of PM2.5 Sources Affecting a Semi-Arid Coastal Region Using a Chemical Mass Balance Model

2013 ◽  
Vol 13 (1) ◽  
pp. 60-71 ◽  
Author(s):  
Priya Subramoney ◽  
Saritha Karnae ◽  
Zuber Farooqui ◽  
Kuruvilla John ◽  
Ashok K. Gupta
Keyword(s):  
Mass Balance ◽  
Coastal Region ◽  
Balance Model ◽  
Chemical Mass Balance ◽  
Mass Balance Model ◽  
Chemical Mass Balance Model ◽  
Semi Arid

scholarly journals Water management using traditional tank cascade systems: a case study of semi-arid region of Southern India

2021 ◽  
Vol 3 (3) ◽  
Author(s):  
Aman Srivastava ◽  
Pennan Chinnasamy
Keyword(s):  
Water Balance ◽  
Mass Balance ◽  
Water Budget ◽  
Water Mass ◽  
Cascade Systems ◽  
Balance Approach ◽  
Urban Catchments ◽  
Spatio Temporal ◽  
Water Mass Balance ◽  
Semi Arid

AbstractMost arid and semi-arid regions of the Southern-Indian peninsula experience frequent drought. To combat this, historically many water recharge structures, such as tank cascade systems, have been constructed. However, in recent years, performance of these tanks, especially for irrigation and groundwater recharge, is limited due to impacts of external factors that are not scientifically understood. This study, for the first time, aimed to explore spatio-temporal variation of water mass balance components and their impact on the Vandiyur tank cascade system (VTCS) in the city of Madurai, India. Study estimated water mass balance components for rural, peri-urban, and urban catchments across VTCS. Catchment-specific algorithms and water budget equation were used to estimate the volume of hydrological parameters. Additionally, land use/land cover maps were developed to understand the significance of using a water balance approach in understanding the behavior of hydrological components governing the water budget of a catchment. Results indicated a rapid increase in the urban area, up to 300%, in peri-urban and urban regions. Urbanization was considered the primary cause of high catchment runoff (40–60% of rainfall). Due to this, seasonal water availability within each tank across catchment was observed inconsistent (0–15%), wherein summer recorded approximately the least tank storage (0–8%). In general, study provided an approach for a practical, water‐focused application demonstrating how the principles of mass balance can help to foster robust water accounting, monitoring, and management. It further emphasized the use of a water balance approach in identifying vulnerable catchments for appropriate tank-rehabilitation-based interventions.

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