scholarly journals Redressing the balance: quantifying net intercatchment groundwater flows

2018 ◽  
Author(s):  
Laurène Bouaziz ◽  
Albrecht Weerts ◽  
Jaap Schellekens ◽  
Eric Sprokkereef ◽  
Jasper Stam ◽  
...  
Keyword(s):  
Water Balance ◽  
Relative Importance ◽  
Hydrological Models ◽  
Headwater Catchments ◽  
Actual Evaporation ◽  
Fractured Aquifers ◽  
Geological Features ◽  
Flow Processes ◽  
Yearly Precipitation ◽  
Regional Groundwater

Abstract. Intercatchment groundwater flows (IGF), defined as groundwater flows across topographic divides, can occur as regional groundwater flows that bypass headwater streams and only drain into the channel further downstream or directly to the sea. However, groundwater flows can also be diverted to adjacent river basins due to geological features (e.g., faults, dipping beds and highly permeable conduits). Even though intercatchment groundwater flows can be a significant part of the water balance, they are often not considered in hydrological studies. Yet, assuming this process to be negligible may introduce misrepresentation of the natural system in hydrological models, for example in regions with complex geological features. The presence of limestone formations in France and Belgium potentially further exacerbates the importance of intercatchment groundwater flows, and thus motivates to question the validity of neglecting intercatchment groundwater flows in the Meuse basin. To isolate and quantify the potential relevance of net intercatchment groundwater flows in this study, we propose a three step approach that relies on the comparison and analysis of (1) observed water balance data within the Budyko framework, (2) results from a suite of different conceptual hydrological models and (3) remote sensing based estimates of actual evaporation. The data of 58 catchments in the Meuse basin provides evidence of the likely presence of significant net intercatchment groundwater flows occurring mainly in small headwater catchments underlain by fractured aquifers. The data suggests that the relative importance of net intercatchment groundwater flows reduces at the scale of the Meuse basin, as regional groundwater flows are mostly expected to be self-contained in large basins. The analysis further suggests that net intercatchment groundwater flow processes vary over the year and that at the scale of the headwaters, net intercatchment groundwater flows can make up a relatively large proportion of the water balance (on average 10 % of mean yearly precipitation) and should be accounted for to prevent overestimating actual evaporation rates.

scholarly journals Redressing the balance: quantifying net intercatchment groundwater flows

2018 ◽  
Vol 22 (12) ◽  
pp. 6415-6434 ◽  
Author(s):  
Laurène Bouaziz ◽  
Albrecht Weerts ◽  
Jaap Schellekens ◽  
Eric Sprokkereef ◽  
Jasper Stam ◽  
...  
Keyword(s):  
Water Balance ◽  
Mean Annual Precipitation ◽  
Relative Importance ◽  
Hydrological Models ◽  
Headwater Catchments ◽  
Actual Evaporation ◽  
Fractured Aquifers ◽  
Geological Features ◽  
Flow Processes ◽  
Regional Groundwater

Abstract. Intercatchment groundwater flows (IGFs), defined as groundwater flows across topographic divides, can occur as regional groundwater flows that bypass headwater streams and only drain into the channel further downstream or directly to the sea. However, groundwater flows can also be diverted to adjacent river basins due to geological features (e.g., faults, dipping beds and highly permeable conduits). Even though intercatchment groundwater flows can be a significant part of the water balance, they are often not considered in hydrological studies. Yet, assuming this process to be negligible may introduce misrepresentation of the natural system in hydrological models, for example in regions with complex geological features. The presence of limestone formations in France and Belgium potentially further exacerbates the importance of intercatchment groundwater flows, and thus brings into question the validity of neglecting intercatchment groundwater flows in the Meuse basin. To isolate and quantify the potential relevance of net intercatchment groundwater flows in this study, we propose a three-step approach that relies on the comparison and analysis of (1) observed water balance data within the Budyko framework, (2) results from a suite of different conceptual hydrological models and (3) remote-sensing-based estimates of actual evaporation. The data of 58 catchments in the Meuse basin provide evidence of the likely presence of significant net intercatchment groundwater flows occurring mainly in small headwater catchments underlain by fractured aquifers. The data suggest that the relative importance of net intercatchment groundwater flows is reduced at the scale of the Meuse basin, as regional groundwater flows are mostly expected to be self-contained in large basins. The analysis further suggests that net intercatchment groundwater flow processes vary over the year and that at the scale of the headwaters, net intercatchment groundwater flows can make up a relatively large proportion of the water balance (on average 10 % of mean annual precipitation) and should be accounted for to prevent overestimating actual evaporation rates.

Estimating the water balance and uncertainty bounds in a highly groundwater-dependent and data-scarce areas: An example for the upper Citarum basin

2021 ◽  
Author(s):  
Steven Reinaldo Rusli ◽  
Albrecht Weerts ◽  
Victor Bense
Keyword(s):  
Water Balance ◽  
Water Storage ◽  
Total Water ◽  
Groundwater Abstraction ◽  
Water Balance Components ◽  
Groundwater Storage ◽  
Actual Evaporation ◽  
Basin Scale ◽  
Basin Water ◽  
Storage Change

<p>In this study, we estimate the water balance components of a highly groundwater-dependent and hydrological data-scarce basin of the upper reaches of the Citarum river in West Java, Indonesia. Firstly, we estimate the groundwater abstraction volumes based on population size and a review of literature (0.57mm/day). Estimates of other components like rainfall, actual evaporation, discharge, and total water storage changes are derived from global datasets and are simulated using a distributed hydrological wflow_sbm model which yields additional estimates of discharge, actual evaporation, and total water storage change. We compare each basin water balance estimate as well as quantify the uncertainty of some of the components using the Extended Triple Collocation (ETC) method.</p><p>The ETC application on four different rainfall estimates suggests a preference of using the CHIRPS product as the input to the water balance components estimates as it delivers the highest r<sup>2</sup>  and the lowest RMSE compared to three other sources. From the different data sources and results of the distributed hydrological modeling using CHIRPS as rainfall forcing, we estimate a positive groundwater storage change between 0.12 mm/day - 0.60 mm/day. These results are in agreement with groundwater storage change estimates based upon GRACE gravimetric satellite data, averaged at 0.25 mm/day. The positive groundwater storage change suggests sufficient groundwater recharge occurs compensating for groundwater abstraction. This conclusion seems in agreement with the observation since 2005, although measured in different magnitudes. To validate and narrow the estimated ranges of the basin water storage changes, a devoted groundwater model is necessary to be developed. The result shall also aid in assessing the current and future basin-scale groundwater level changes to support operational water management and policy in the Upper Citarum basin.</p>

scholarly journals Comparison of different evaporation estimates over the African continent

2014 ◽  
Vol 18 (1) ◽  
pp. 193-212 ◽  
Author(s):  
P. Trambauer ◽  
E. Dutra ◽  
S. Maskey ◽  
M. Werner ◽  
F. Pappenberger ◽  
...  
Keyword(s):  
Land Surface ◽  
Hydrological Model ◽  
Hydrological Models ◽  
African Continent ◽  
Land Surface Models ◽  
Continental Scale ◽  
Actual Evaporation ◽  
Balance Approach ◽  
Surface Models ◽  
Energy Balance Approach

Abstract. Evaporation is a key process in the water cycle with implications ranging, inter alia, from water management to weather forecast and climate change assessments. The estimation of continental evaporation fluxes is complex and typically relies on continental-scale hydrological models or land-surface models. However, it appears that most global or continental-scale hydrological models underestimate evaporative fluxes in some regions of Africa, and as a result overestimate stream flow. Other studies suggest that land-surface models may overestimate evaporative fluxes. In this study, we computed actual evaporation for the African continent using a continental version of the global hydrological model PCR-GLOBWB, which is based on a water balance approach. Results are compared with other independently computed evaporation products: the evaporation results from the ECMWF reanalysis ERA-Interim and ERA-Land (both based on the energy balance approach), the MOD16 evaporation product, and the GLEAM product. Three other alternative versions of the PCR-GLOBWB hydrological model were also considered. This resulted in eight products of actual evaporation, which were compared in distinct regions of the African continent spanning different climatic regimes. Annual totals, spatial patterns and seasonality were studied and compared through visual inspection and statistical methods. The comparison shows that the representation of irrigation areas has an insignificant contribution to the actual evaporation at a continental scale with a 0.5° spatial resolution when averaged over the defined regions. The choice of meteorological forcing data has a larger effect on the evaporation results, especially in the case of the precipitation input as different precipitation input resulted in significantly different evaporation in some of the studied regions. ERA-Interim evaporation is generally the highest of the selected products followed by ERA-Land evaporation. In some regions, the satellite-based products (GLEAM and MOD16) show a different seasonal behaviour compared to the other products. The results from this study contribute to a better understanding of the suitability and the differences between products in each climatic region. Through an improved understanding of the causes of differences between these products and their uncertainty, this study provides information to improve the quality of evaporation products for the African continent and, consequently, leads to improved water resources assessments at regional scale.

scholarly journals Multimodel Estimate of the Global Terrestrial Water Balance: Setup and First Results

2011 ◽  
Vol 12 (5) ◽  
pp. 869-884 ◽  
Author(s):  
Ingjerd Haddeland ◽  
Douglas B. Clark ◽  
Wietse Franssen ◽  
Fulco Ludwig ◽  
Frank Voß ◽  
...  
Keyword(s):  
Water Balance ◽  
Land Surface ◽  
Water Model ◽  
Hydrological Models ◽  
Model Intercomparison ◽  
Land Surface Models ◽  
Surface Models ◽  
Terrestrial Water ◽  
Intercomparison Project ◽  
Energy Balance Approach

Abstract Six land surface models and five global hydrological models participate in a model intercomparison project [Water Model Intercomparison Project (WaterMIP)], which for the first time compares simulation results of these different classes of models in a consistent way. In this paper, the simulation setup is described and aspects of the multimodel global terrestrial water balance are presented. All models were run at 0.5° spatial resolution for the global land areas for a 15-yr period (1985–99) using a newly developed global meteorological dataset. Simulated global terrestrial evapotranspiration, excluding Greenland and Antarctica, ranges from 415 to 586 mm yr−1 (from 60 000 to 85 000 km3 yr−1), and simulated runoff ranges from 290 to 457 mm yr−1 (from 42 000 to 66 000 km3 yr−1). Both the mean and median runoff fractions for the land surface models are lower than those of the global hydrological models, although the range is wider. Significant simulation differences between land surface and global hydrological models are found to be caused by the snow scheme employed. The physically based energy balance approach used by land surface models generally results in lower snow water equivalent values than the conceptual degree-day approach used by global hydrological models. Some differences in simulated runoff and evapotranspiration are explained by model parameterizations, although the processes included and parameterizations used are not distinct to either land surface models or global hydrological models. The results show that differences between models are a major source of uncertainty. Climate change impact studies thus need to use not only multiple climate models but also some other measure of uncertainty (e.g., multiple impact models).

scholarly journals Water flow pathways and the water balance within a head-water catchment containing a dambo: inferences drawn from hydrochemical investigations

1999 ◽  
Vol 3 (4) ◽  
pp. 581-591 ◽  
Author(s):  
M. P. McCartney ◽  
C. Neal
Keyword(s):  
Water Balance ◽  
Stream Water ◽  
Management Strategies ◽  
Dry Season ◽  
Sub Saharan Africa ◽  
Flow Paths ◽  
Headwater Catchments ◽  
Sub Saharan ◽  
Flow Pathways ◽  
Water Catchment

Abstract. Dambos, seasonally saturated wetlands, are widespread in headwater catchments in sub-Saharan Africa. It is widely believed that they play an important role in regional hydrology but, despite research conducted over the last 25 years, their hydrological functions remain poorly understood. To improve conceptualisation of hydrological flow paths and investigate the water balance of a small Zimbabwean catchment containing a single dambo, measurements of alkalinity and chloride in different water types within the catchment have been used as chemical markers. The temporal variation in alkalinity is consistent with the premise that all stream water, including the prolonged dry season recession, is derived predominantly from shallow sources. The proposition that dry season recession flows are maintained by water travelling at depth within the underlying saprolite is not substantiated. There is evidence that a low permeability clay lens, commonly present in many dambos, acts as a barrier for vertical water exchange. However, the highly heterogeneous chemical composition of different waters precludes quantitative hydrograph split-ting using end member mixing analysis. Calculation of the chloride mass-balance confirms that, after rainfall, evaporation is the largest component of the catchment water budget. The study provides improved understanding of the hydrological functioning of dambos. Such understanding is essential for the development and implementation of sustainable management strategies for this landform.

scholarly journals Exploring the Capability of Natural Flood Management Approaches in Groundwater-Dominated Chalk Streams

Water ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2212
Author(s):  
Imogen Barnsley ◽  
Rebecca Spake ◽  
Justin Sheffield ◽  
Julian Leyland ◽  
Tim Sykes ◽  
...  
Keyword(s):  
Positive Impact ◽  
Flood Management ◽  
Evidence Base ◽  
Hydrological Models ◽  
Headwater Catchments ◽  
Management Interventions ◽  
Management Application ◽  
Flow Pathways ◽  
Chalk Streams ◽  
Management Approaches

This study aims to address the gap in the Natural Flood Management (NFM) evidence base concerning its implementation potential in groundwater-dominated catchments. We generated a typology of 198 chalk catchments using redundancy analysis and hierarchical clustering. Three catchment typologies were identified: (1) large catchments, (2) headwater catchments with permeable soils, and (3) catchments with impermeable soils and surfaces (urban and suburban land uses). The literature suggests that natural flood management application is most effective for catchments <20 km2, reducing the likelihood of significant flood mitigation in large catchments. The relatively lower proportion of surface runoff and higher recharge in permeable catchments diminishes natural flood management’s likely efficacy. Impermeable catchments are most suited to natural flood management due to a wide variety of flow pathways, making the full suite of natural flood management interventions applicable. Detailed groundwater flood maps and hydrological models are required to identify catchments where NFM can be used in a targeted manner to de-synchronise sub-catchment flood waves or to intercept runoff generated via groundwater emergence. Whilst our analysis suggests that most chalk groundwater-dominated catchments in this sample are unlikely to benefit from significant flood reductions due to natural flood management, the positive impact on ecosystem services and biodiversity makes it an attractive proposition.

Groundwater recharge estimates combining soil isotope profiles and classical soil water monitoring techniques

2021 ◽  
Author(s):  
Nina Krüger ◽  
Christoph Külls ◽  
Marcel Kock
Keyword(s):  
Soil Moisture ◽  
Water Balance ◽  
Groundwater Recharge ◽  
Soil Water ◽  
Soil Profile ◽  
Tunable Diode Laser ◽  
Soil Water Balance ◽  
Advection Dispersion ◽  
Flow Processes ◽  
Percolation Rate

&lt;p&gt;To improve knowledge of hydrological and hydrogeological flow processes and their dependency on climate conditions it is becoming increasingly important to integrate sensors technology, independent observation methods, and new modeling techniques. Established isotope methods are usually regarded as a supplement and extension to classical hydrological investigation methods but are rarely included in soil water balance models. However, the combination could close knowledge gaps and thus lead to more precise and realistic predictions and therefore to better water management. Within the Wasserpfad project, a project of the Department of Civil Engineering at the TH L&amp;#252;beck, soil moisture has been measured since May 2018. SMT100 soil moisture sensors from TRUEBNER GmbH are used at depths of 20, 40, 60, and 80 cm. Next to the station a 2m deep soil profile was taken in 2020, to estimate groundwater recharge using stable isotope equilibration methods and cryogenic extraction combined with soil water balance modeling. Vertical profiles of stable isotopes have been determined with a 10-cm resolution and measured with Tunable Diode Laser spectrometry. Percolation through the soil profile has been estimated based on the convolution of a seasonal input function using advection-dispersion transport models. Percolation rate estimate based on environmental isotope profiles results in 230 mm per year. Fitting of the advection-dispersion equation using a sinusoidal isotope input fitted to available time series provides an estimate of 255 mm per year. This difference is due to the dispersion effect on the isotope minima and maxima. The result of modeling the soil moisture data with a soil water balance model integrating the Richards equation for water transport and Penmen-Monteith based calculation of actual evaporation is used to verify the percolation rates. The analysis of soil moisture and isotope data by modeling provides a direct and efficient way to estimate the percolation rate. The combination of isotope methods with classical hydrological measuring techniques offers the possibility to verify results, to calibrate models, or to investigate the limits of isotope methods. Thus, flow processes can be predicted more reliably in the future.&lt;/p&gt;

Hydrological aspects of an industrial landfill

2019 ◽  
pp. 225-233
Author(s):  
Pille Kängsepp ◽  
Peter Dahlblom
Keyword(s):  
Water Balance ◽  
The South ◽  
South West ◽  
Yearly Precipitation ◽  
Help Model ◽  
Hydrologic Evaluation

A water balance for a landfill in the South-West of Sweden has been performed. The waterbalance is based on measured values of leachate and calculated values of potentialevaporation using Penman's equation. The calculations include a period of 6 years (1995-200 I). During this period, the yearly precipitation was 6 I 0-1180 mm in the Halmstad area. Itwas concluded that the total storage of leachate in the landfill and in the ponds increased withtime. If increasing tendency will proceed then the amount of leachate generated might behigher during the next years and similar to results found in the literature. There is a need forthe more physical based model, the Hydrologic Evaluation of Landfill Performance (HELP)model, for calculation in order to take into account the top cover soils and vegetationinfluence.

Evaluation of precipitation and actual evaporation products over the Nile Basin

2020 ◽  
Author(s):  
Oscar M. Baez-Villanueva ◽  
Ian McNamara ◽  
Mauricio Zambrano-Bigiarini ◽  
Lars Ribbe
Keyword(s):  
Water Balance ◽  
Remote Sensing Data ◽  
Data Availability ◽  
Nile Basin ◽  
Actual Evaporation ◽  
Balance Analysis ◽  
Streamflow Data ◽  
Spatio Temporal ◽  
Eta Products ◽  
Annual Scale

&lt;p&gt;An improved representation of the spatio-temporal patterns of climatological variables is crucial for ecological, agricultural, and hydrological applications and can improve the decision-making process. Traditionally, precipitation (P) and actual evaporation (ETa) are estimated using ground-based measurements from meteorological stations. However, the estimation of spatial patterns derived solely from point-based measurements is subject to large uncertainties, particularly in data-scarce regions as the Nile Basin, which has an area of about 3 million km&lt;sup&gt;2&lt;/sup&gt;. This study evaluates six state-of-the-art P products (CHIRPSv2, CMORPHv1, CRU TS4.02, MSWEPv2.2, PERSIANN-CDR and GPCCv2018) and five ETa products (SSEBop, MOD16-ET, WaPOR, GLEAM and GLDAS) over the Nile Basin to identify the best-performing products. The P products were evaluated at monthly and annual temporal scales (from 1983 onwards) through a point-to-pixel approach using the modified Kling-Gupta Efficiency and its components (linear correlation, bias, and variability ratio) as continuous performance indices. The ETa products were evaluated through the water balance approach (due to the lack of ground-based ETa measurements) for 2009-2018 at the multiannual scale. Because streamflow data were not available for this period, an empirical model based on the Random Forest machine learning technique was used to estimate streamflow at 21 catchments at the monthly scale. For this purpose, we used streamflow data from 1983 to 2005 as the dependent variable, while CHIRPSv2 precipitation and ERA5 potential evaporation and temperature data were used as predictors. For the catchments where the model performed well over the validation period, streamflow estimates were generated and used for the water balance analysis. Our results show that CHIRPSv2 was the best performing P product at monthly and annual scale when compared with ground-based measurements, while WaPOR was the best-performing ETa product in the water balance evaluation. This study demonstrates how remote sensing data can be evaluated over extremely data-scarce scenarios to estimate the magnitude of key meteorological variables, yet also highlights the importance of improving data availability so that the characterisation of these variables can be further evaluated and improved.&lt;/p&gt;

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