scholarly journals A simple method for water balance estimation based on the empirical method and remotely sensed evapotranspiration estimates

2020 ◽  
Vol 22 (2) ◽  
pp. 440-451
Author(s):  
George Falalakis ◽  
Alexandra Gemitzi
Keyword(s):  
Water Balance ◽  
Performance Metrics ◽  
Empirical Relationship ◽  
Remotely Sensed ◽  
Empirical Method ◽  
Data Availability ◽  
Water Balance Components ◽  
Time Step ◽  
Simple Method ◽  
Satisfactory Outcome

Abstract Developing a methodology for water balance estimation is a significant challenge, especially in areas with little or no gauging. This is because direct measurements of all the water balance components are not feasible. To overcome this issue, we propose a simple methodology based on the predefined empirical relationship between remotely sensed evapotranspiration (ET), i.e. Moderate Resolution Imaging Spectroradiometer (MODIS) ET and groundwater recharge (GR), and readily available precipitation data at the monthly time step. The developed methodology was applied in seven catchments in NE Greece using time series of precipitation and remotely sensed ET from 2009 to 2019. The potential of the proposed method to accurately estimate the water balance was assessed by the comparison of the individual water balance components against modeled values. Three performance metrics were examined and indicated that the methodology produces a satisfactory outcome. Our results indicated mean ET accounting for approximately 54% of precipitation, mean GR of 24% and mean surface runoff approximately 22% of precipitation in the study area. The proposed approach was implemented using freely available remotely sensed products and the free R software for statistical computing and graphics, offering thus a convenient and inexpensive alternative for water balance estimation, even for basins with limited data availability.

scholarly journals Satellite-based evapotranspiration and crop coefficient for irrigated sorghum in the Gezira scheme, Sudan

2006 ◽  
Vol 3 (3) ◽  
pp. 793-817
Author(s):  
M. A. Bashir ◽  
T. Hata ◽  
A. W. Abdelhadi ◽  
H. Tanakamaru ◽  
A. Tada
Keyword(s):  
Energy Balance ◽  
Irrigation Water ◽  
Crop Coefficient ◽  
Remotely Sensed ◽  
Data Availability ◽  
Balance Model ◽  
Time Data ◽  
Remotely Sensed Data ◽  
Time Step ◽  
Key Factor

Abstract. The availability of the actual water use from agricultural crops is considered as the key factor for irrigation water management, water resources planning, and water allocation. Traditionally, evapotranspiration (ET) has been estimated in the Gezira scheme by multiplying the reference evapotranspiration (ETo) by crop coefficient (kc) which is derived from the phenomenological crop stages. Recently, advanced developed energy balance models assist to estimate ET through remotely sensed data. In this study Enhanced Thematic Mapper Plus (ETM+) images were used to estimate spatial distribution of daily, monthly and seasonal ET for irrigated sorghum in the Gezira scheme, Sudan. The daily ET maps were also used to estimate kc over time and space. Results of remotely sensed based energy balance were compared with actual measurements conducted during 2004/05 season. The daily actual ET values estimated using the energy balance model during the satellite acquisition dates (28 July, 29 August, 16 October and 17 November) were 4.7, 5.5, 7.1 and 2.7 mm/day, while the average seasonal evapotranspiration for irrigated sorghum estimated to be around 596 mm. The remotely estimated kc values in the initial, crop development, mid-season and late-season stages were 0.62, 0.85, 1.15, and 0.48 respectively. On the other hand the widely used tradition kc values during the pervious mention stages are 0.55, 0.94, 1.21 and 0.65, respectively. This research shows that remotely sensed measurements can help objectively analyzed the irrigation water requirement for different field crops on daily and seasonal time step. Moreover, the remotely sensed real-time data availability provides the system managers with information that not previously available.

scholarly journals Assessment of the ParFlow–CLM CONUS 1.0 integrated hydrologic model: evaluation of hyper-resolution water balance components across the contiguous United States

2021 ◽  
Vol 14 (12) ◽  
pp. 7223-7254
Author(s):  
Mary M. F. O'Neill ◽  
Danielle T. Tijerina ◽  
Laura E. Condon ◽  
Reed M. Maxwell
Keyword(s):  
United States ◽  
High Resolution ◽  
Water Balance ◽  
Water Table ◽  
Performance Metrics ◽  
System Modeling ◽  
Hydrologic Model ◽  
Surface Model ◽  
Water Balance Components ◽  
Continental Scale

Abstract. Recent advancements in computational efficiency and Earth system modeling have awarded hydrologists with increasingly high-resolution models of terrestrial hydrology, which are paramount to understanding and predicting complex fluxes of moisture and energy. Continental-scale hydrologic simulations are, in particular, of interest to the hydrologic community for numerous societal, scientific, and operational benefits. The coupled hydrology–land surface model ParFlow–CLM configured over the continental United States (PFCONUS) has been employed in previous literature to study scale-dependent connections between water table depth, topography, recharge, and evapotranspiration, as well as to explore impacts of anthropogenic aquifer depletion to the water and energy balance. These studies have allowed for an unprecedented process-based understanding of the continental water cycle at high resolution. Here, we provide the most comprehensive evaluation of PFCONUS version 1.0 (PFCONUSv1) performance to date by comparing numerous modeled water balance components with thousands of in situ observations and several remote sensing products and using a range of statistical performance metrics for evaluation. PFCONUSv1 comparisons with these datasets are a promising indicator of model fidelity and ability to reproduce the continental-scale water balance at high resolution. Areas for improvement are identified, such as a positive streamflow bias at gauges in the eastern Great Plains, a shallow water table bias over many areas of the model domain, and low bias in seasonal total water storage amplitude, especially for the Ohio, Missouri, and Arkansas River basins. We discuss several potential sources for model bias and suggest that minimizing error in topographic processing and meteorological forcing would considerably improve model performance. Results here provide a benchmark and guidance for further PFCONUS model development, and they highlight the importance of concurrently evaluating all hydrologic components and fluxes to provide a multivariate, holistic validation of the complete modeled water balance.

Improvement of uncertainty estimation in global hydrological models by using high resolution satellite data as an interpolator

2020 ◽  
Author(s):  
Rogier Westerhoff ◽  
Frederika Mourot ◽  
Conny Tschritter
Keyword(s):  
High Resolution ◽  
Water Balance ◽  
Groundwater Recharge ◽  
Satellite Data ◽  
Spatial Scales ◽  
Remotely Sensed ◽  
Google Earth ◽  
Data Driven ◽  
Hydrological Models ◽  
Water Balance Components

<p>Global hydrological models often ingest remotely-sensed observations supported by ground-truthed data in attempts to better quantify water balance components, e.g. soil water content, evapotranspiration, runoff/discharge, groundwater recharge. However, the scaling up process from local observations to that global, coarse, scale contains large uncertainty, often undermining the relevance of water balance calculations.</p><p>With recent more advanced high-resolution satellite data, freely available at 10m spatial resolution and (sub-) weekly temporal resolution, there is a possibility to reduce uncertainty in that upscaling. However, there are two challenges in doing so when working with global models: exponential increase of computational effort, and the need for quantifying the yet unknown uncertainty of assumptions that coarse global model cells and their underlying equations bring.</p><p>This study hypothesises that a bottom-up approach with high-resolution satellite data and in situ observations will better constrain and quantify uncertainty. By using these more spatially-explicit data, we make the case that the estimation of water balance components should become more data-driven. We propose a more data-driven model that improves uncertainty of estimation and scalability by using more sophisticated, remotely-sensed interpolation layers.</p><p>Our case study shows New Zealand-wide estimates of evapotranspiration and groundwater recharge at two resolutions: 1km x 1km, using an earlier developed model and MODIS satellite data; and a novel approach at 10m x 10m using Sentinel-1 and Sentinel-2 data to better incorporate impervious areas (e.g., anthropogenic urbanised land covers) and small land patches (e.g., small forestry areas). We then study the implications of using different spatial scales and quantify the differences between 10m x 10m versus 1km x 1km model pixel estimates. Our method is applied in the Google Earth Engine, a free-for-research high performance cloud computing facility, hence providing powerful computational resources and making our approach easily scalable to global, regional and catchment scales. </p><p>Finally, we discuss what underlying model assumptions in traditional models could be changed to facilitate a method that works consistently at these different scales.</p>

scholarly journals Assessment of the ParFlow-CLM CONUS 1.0 integrated hydrologic model: Evaluation of hyper-resolution water balance components across the contiguous United States

2020 ◽  
Author(s):  
Mary M. F. O'Neill ◽  
Danielle T. Tijerina ◽  
Laura E. Condon ◽  
Reed M. Maxwell
Keyword(s):  
United States ◽  
High Resolution ◽  
Water Balance ◽  
Water Table ◽  
Performance Metrics ◽  
System Modeling ◽  
Hydrologic Model ◽  
Surface Model ◽  
Water Balance Components ◽  
Continental Scale

Abstract. Recent advancements in computational efficiency and earth system modeling have awarded hydrologists with increasingly high-resolution models of terrestrial hydrology, which are paramount to understanding and predicting complex fluxes of moisture and energy. Continental-scale hydrologic simulations are, in particular, of interest to the hydrologic community for numerous societal, scientific and operational benefits. The coupled hydrology-land surface model ParFlow-CLM configured over the continental United States (PFCONUS) has been employed in previous literature to study scale-dependent connections between water table depth, topography, recharge, and evapotranspiration, as well as to explore impacts of anthropogenic aquifer depletion to the water and energy balance. These studies have allowed for an unprecedented, process-based understanding of the continental water cycle at high resolution. Here, we provide the most comprehensive evaluation of PFCONUS version 1.0 (PFCONUSv1) performance to date, comparing numerous modeled water balance components with thousands of in situ observations and several remote sensing products, and using a range of statistical performance metrics for evaluation. PFCONUSv1 comparisons with these datasets are a promising indicator of model fidelity and ability to appropriately reproduce the continental-scale water balance at high resolution. Areas for improvement are identified, such as a positive streamflow bias at gauges in the eastern Great Plains, a shallow water table bias over many areas of the model domain, and low bias in seasonal total water storage amplitude especially for the Ohio, Missouri and Arkansas river basins. We discuss several potential sources for model bias and suggest that minimizing error in topographic processing and meteorological forcing would considerably improve model performance. Results here provide a benchmark and guidance for further PFCONUS model development, and they highlight the importance of concurrently evaluating all hydrologic components and fluxes to provide a multivariate, holistic validation of the complete modeled water balance.

A first look at ERA5 for physically based water balance modelling of the Devoll Catchment, Albania

2020 ◽  
Author(s):  
María Herminia Pesci ◽  
Fenja Voges ◽  
Nils Rüther ◽  
Kristian Förster
Keyword(s):  
Water Balance ◽  
Meteorological Data ◽  
Model Performance ◽  
Data Availability ◽  
Capital City ◽  
High Temporal Resolution ◽  
Time Step ◽  
Reanalysis Dataset ◽  
River Catchment ◽  
Physically Based

<p>The need for effective water resources management has turned into a major challenge, especially in the face of climate change. Meteorological data is not always readily available and thus the task of predicting the response of hydrological systems becomes complicated. For this reason, climate reanalysis datasets are used as a viable alternative. They combine models with data from satellites and ground sensors and provide consistent long-term meteorological conditions with high temporal resolution. The ERA5 reanalysis dataset was produced and is continuously updated by the European Centre for Medium-Range Weather Forecasts (ECMWF). Within this framework, the ERA5 reanalysis dataset has been applied to predict the hydrological response of the Devoll River catchment in Albania. Due to its location, Albania belongs to the Mediterranean climatic belt, which is characterized by hot dry summers and mild rainy winters. The Devoll River catchment is situated south from the capital city Tirana and covers a surface of around 3140 km<sup>2</sup>. The flow regime of this catchment consists mainly of snowmelt in the upstream mountainous part, whereas precipitation dominates the lower regions. The simulation of the different flow components was carried out with the latest version of the Water Balance and Simulation Model (WaSiM) on a daily time step. The performance of the simulation was evaluated with the Nash-Sutcliffe (NSE) and the Kling-Gupta (KGE) efficiencies, yielding values of 0.66 and 0.80, respectively. Although the model performance suggests some deficiencies, it is considered satisfactory given that ERA5 is a reanalysis dataset with modelled precipitation fields. From the resulting hydrographs, it is possible to infer that observed and simulated runoff follow the same dynamics and a close correspondence between flow peaks can be achieved. These results finally reinforce the idea of applying ERA5 datasets in cases where meteorological input data availability is low or even absent.</p>

scholarly journals Afforestation of Degraded Croplands as a Water-Saving Option in Irrigated Region of the Aral Sea Basin

Water ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1433
Author(s):  
Navneet Kumar ◽  
Asia Khamzina ◽  
Patrick Knöfel ◽  
John P. A. Lamers ◽  
Bernhard Tischbein
Keyword(s):  
Land Use ◽  
Water Balance ◽  
Water Supply ◽  
Water Availability ◽  
Irrigation Water ◽  
Water Saving ◽  
Aral Sea ◽  
Water Balance Components ◽  
Study Region ◽  
Trade Offs

Climate change is likely to decrease surface water availability in Central Asia, thereby necessitating land use adaptations in irrigated regions. The introduction of trees to marginally productive croplands with shallow groundwater was suggested for irrigation water-saving and improving the land’s productivity. Considering the possible trade-offs with water availability in large-scale afforestation, our study predicted the impacts on water balance components in the lower reaches of the Amudarya River to facilitate afforestation planning using the Soil and Water Assessment Tool (SWAT). The land-use scenarios used for modeling analysis considered the afforestation of 62% and 100% of marginally productive croplands under average and low irrigation water supply identified from historical land-use maps. The results indicate a dramatic decrease in the examined water balance components in all afforestation scenarios based largely on the reduced irrigation demand of trees compared to the main crops. Specifically, replacing current crops (mostly cotton) with trees on all marginal land (approximately 663 km2) in the study region with an average water availability would save 1037 mln m3 of gross irrigation input within the study region and lower the annual drainage discharge by 504 mln m3. These effects have a considerable potential to support irrigation water management and enhance drainage functions in adapting to future water supply limitations.

Effect of watershed subdivision on simulation of water balance components

2006 ◽  
Vol 20 (5) ◽  
pp. 1137-1156 ◽  
Author(s):  
M. P. Tripathi ◽  
N. S. Raghuwanshi ◽  
G. P. Rao
Keyword(s):  
Water Balance ◽  
Water Balance Components

Some assessments of the potential 2 � CO2 climatic effects on water balance components in the eastern mediterranean

1994 ◽  
Vol 27 (4) ◽  
pp. 351-371 ◽  
Author(s):  
M. Segal ◽  
P. Alpert ◽  
U. Stein ◽  
M. Mandel ◽  
M. J. Mitchell
Keyword(s):  
Water Balance ◽  
Eastern Mediterranean ◽  
Water Balance Components ◽  
Climatic Effects

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>

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