scholarly journals Esquema explícito para la solución numérica del flujo no saturado en medios heterogéneos bajo condición de niveles freáticos someros.

2021 ◽  
Vol 27 ◽  
pp. 47-58
Author(s):  
Erik Zimmermann
Keyword(s):  
Hydrus 1D

Se propone un esquema numérico explícito de 4 celdas (4C) para la integración de las ecuaciones de flujo en la zona no saturada diseñado para áreas de llanura con niveles freáticos someros. El esquema contempla un coeficiente de ponderación para definir la conductividad hidráulica no saturada representativa entre celdas adyacentes y considera la heterogeneidad de cada horizonte edáfico. El esquema 4C es comparado con estimaciones realizadas por el HYDRUS-1D en dos grupos de ensayos modelados, uno con saturación de superficie durante 10 días y otro con series de precipitaciones durante 96 días. Los ensayos numéricos se hicieron para 14 tipos de asociaciones de suelos características de la zona de estudio (A° del Azul, Bs. As.) y 6 profundidades freáticas (entre 300 y 50 cm). Para el primer ensayo, la respuesta del esquema se considera aceptable con diferencias porcentuales del orden al 19%. En el segundo, el esquema propuesto estimó satisfactoriamente las recargas freáticas con diferencias porcentuales del 1% entre ambos esquemas. Complementariamente, mostró un muy buen ajuste en las evoluciones de contenidos de humedad de cada estrato. Estos resultados validan el esquema simplificado propuesto permitiendo una respuesta rápida en términos de tiempo computacional.

scholarly journals Sensitivity of groundwater recharge using climatic analogues and HYDRUS-1D

2012 ◽  
Vol 16 (8) ◽  
pp. 2485-2497 ◽  
Author(s):  
B. Leterme ◽  
D. Mallants ◽  
D. Jacques
Keyword(s):  
Water Balance ◽  
Groundwater Recharge ◽  
Potential Evapotranspiration ◽  
Future Climate ◽  
Annual Precipitation ◽  
Balance Model ◽  
Subtropical Climate ◽  
Northern Spain ◽  
Near Surface ◽  
Hydrus 1D

Abstract. The sensitivity of groundwater recharge to different climate conditions was simulated using the approach of climatic analogue stations, i.e. stations presently experiencing climatic conditions corresponding to a possible future climate state. The study was conducted in the context of a safety assessment of a future near-surface disposal facility for low and intermediate level short-lived radioactive waste in Belgium; this includes estimation of groundwater recharge for the next millennia. Groundwater recharge was simulated using the Richards based soil water balance model HYDRUS-1D and meteorological time series from analogue stations. This study used four analogue stations for a warmer subtropical climate with changes of average annual precipitation and potential evapotranspiration from −42% to +5% and from +8% to +82%, respectively, compared to the present-day climate. Resulting water balance calculations yielded a change in groundwater recharge ranging from a decrease of 72% to an increase of 3% for the four different analogue stations. The Gijon analogue station (Northern Spain), considered as the most representative for the near future climate state in the study area, shows an increase of 3% of groundwater recharge for a 5% increase of annual precipitation. Calculations for a colder (tundra) climate showed a change in groundwater recharge ranging from a decrease of 97% to an increase of 32% for four different analogue stations, with an annual precipitation change from −69% to −14% compared to the present-day climate.

Statistisch-klimatologische Analyse zum Verhalten der Evapotranspiration von Winterweizen mittels Lysimeterdaten und Modellergebnissen in Deutschland

2021 ◽  
Author(s):  
Alice Künzel
Keyword(s):  
Hydrus 1D

<p>Winterweizen ist die wichtigste Kulturpflanze in Deutschland, weshalb in der vorliegenden Arbeit eine statistisch-klimatologische Analyse der Evapotranspiration von Winterweizen mittels Lysimeterdaten und Modellergebnissen in Groß Lüsewitz, Brandis und Potsdam erfolgte. Die ausgewählten Standorte unterscheiden sich hinsichtlich der klimatischen und edaphischen Verhältnisse. In Groß Lüsewitz und in Brandis wird die aktuelle Evapotranspiration (AET) mittels Lysimetern gemessen. Diese Messdaten wurden mit der modellierten AET der Bodenwasserhaushaltsmodelle METVER und HYDRUS-1D verglichen, wobei nur Anbaujahre des Winterweizens am jeweiligen Lysimeterstandort berücksichtigt wurden. Für Potsdam erfolgte für vier Klimaperioden nur eine modellbasierte Auswertung der AET. Die Analyse beschränkt sich an allen Standorten auf die Vegetationsperiode des Winterweizens, welche die Monate März bis August umfasst.</p> <p>Die für das Wachstum des Winterweizens entscheidenden Monate sind April bis Juni. In dieser Hauptwachstumszeit ist der Wasserverbrauch des Winterweizens am größten, weshalb eine kontinuierliche Wasserversorgung gewährleistet sein muss. Die Analyse ergab, dass die Variabilität der gemessenen AET mittels beider Bodenwasserhaushaltsmodelle an den Lysimeterstandorten, wenn auch unterschiedlich gut im Vergleich zur gemessenen AET auf den Lysimetern, simuliert werden konnte.</p> <p>Die potentielle Evapotranspiration (ETP) wird in METVER mit einem modifizierten Berechnungsansatz nach Turc-Wendling und in HYDRUS-1D nach dem Ansatz von Penman-Monteith modelliert. In Groß Lüsewitz und in Potsdam wurden trotz der unterschiedlichen Berechnungsansätze ähnliche Ergebnisse erzielt. Für Brandis dagegen ergaben sich deutlich unterschiedliche Ergebnisse.</p> <p>Wenn sehr trockene Bedingungen in einzelnen Monaten der jeweiligen Anbaujahre vorlagen, war die Differenz zwischen der modellierten ETP des jeweiligen Bodenwasserhaushaltsmodells und der gemessenen AET auf den Lysimetern deutlich ausgeprägt. Anhand des verwendeten Ariditätsindexes konnte festgestellt werden, dass in Groß Lüsewitz die Vegetationsperiode des Winterweizens bei METVER in vier und bei HYDRUS in einem von insgesamt 26 Anbaujahren durchweg sehr trocken war. In Brandis waren es bei METVER drei und bei HYDRUS zwei von insgesamt 12 Anbaujahren.</p> <p>Mittels einer modellbasierten Trendanalyse der ETP und der AET am jeweiligen Standort konnte für Groß Lüsewitz im Zeitraum 1975-2020, für Brandis (1981-2020) und für Potsdam (1901-2020) eine zunehmende Trockenheit festgestellt werden, sodass die Bewässerung von Winterweizen hier zukünftig an Bedeutung gewinnen wird.</p>

scholarly journals Coupling DSSAT and HYDRUS-1D for simulations of soil water dynamics in the soil-plant-atmosphere system

2018 ◽  
Vol 66 (2) ◽  
pp. 232-245 ◽  
Author(s):  
Vakhtang Shelia ◽  
Jirka Šimůnek ◽  
Ken Boote ◽  
Gerrit Hoogenbooom
Keyword(s):  
Water Balance ◽  
Soil Water ◽  
Crop Yield ◽  
Crop Growth ◽  
Water Dynamics ◽  
Soil Water Balance ◽  
Soil Water Dynamics ◽  
Atmosphere System ◽  
Water Contents ◽  
Hydrus 1D

AbstractAccurate estimation of the soil water balance of the soil-plant-atmosphere system is key to determining the availability of water resources and their optimal management. Evapotranspiration and leaching are the main sinks of water from the system affecting soil water status and hence crop yield. The accuracy of soil water content and evapotranspiration simulations affects crop yield simulations as well. DSSAT is a suite of field-scale, process-based crop models to simulate crop growth and development. A “tipping bucket” water balance approach is currently used in DSSAT for soil hydrologic and water redistribution processes. By comparison, HYDRUS-1D is a hydrological model to simulate water flow in soils using numerical solutions of the Richards equation, but its approach to crop-related process modeling is rather limited. Both DSSAT and HYDRUS-1D have been widely used and tested in their separate areas of use. The objectives of our study were: (1) to couple HYDRUS-1D with DSSAT to simulate soil water dynamics, crop growth and yield, (2) to evaluate the coupled model using field experimental datasets distributed with DSSAT for different environments, and (3) to compare HYDRUS-1D simulations with those of the tipping bucket approach using the same datasets. Modularity in the software design of both DSSAT and HYDRUS-1D made it easy to couple the two models. The pairing provided the DSSAT interface an ability to use both the tipping bucket and HYDRUS-1D simulation approaches. The two approaches were evaluated in terms of their ability to estimate the soil water balance, especially soil water contents and evapotranspiration rates. Values of thedindex for volumetric water contents were 0.9 and 0.8 for the original and coupled models, respectively. Comparisons of simulations for the pod mass for four soybean and four peanut treatments showed relatively highdindex values for both models (0.94–0.99).

scholarly journals Telhado verde: desempenho do sistema construtivo na redução do escoamento superficial

2013 ◽  
Vol 13 (1) ◽  
pp. 161-174 ◽  
Author(s):  
Pedro Tyaquiçã da Silva Santos ◽  
Sylvana Melo dos Santos ◽  
Suzana Maria Gico Lima Montenegro ◽  
Artur Paiva Coutinho ◽  
Glawbber Spíndola Saraiva de Moura ◽  
...  
Keyword(s):  
Hydrus 1D

Na atualidade, metade da população mundial reside em centros urbanos, e os impactos negativos decorrentes de eventos hidrológicos têm sido recorrentes, visto que, com o aumento da impermeabilização, há redução nas taxas de infiltração, levando à diminuição da recarga dos aquíferos e à diminuição do escoamento de base. Consequentemente, o escoamento superficial é intensificado, aumentando a frequência e a magnitude dos picos de cheia, o que pode resultar na ocorrência de inundações, especialmente nos centros urbanos. Por outro lado, verifica-se já há algum tempo o emprego de telhados verdes em várias partes do mundo para contribuição arquitetônica estética e melhoria do conforto ambiental. Além desses enfoques, esta solução vem sendo tratada, também, como uma estrutura de controle do escoamento pluvial. Considerando características reais e os dados obtidos em campo, foi realizada a simulação da dinâmica da água em dois telhados verdes, com o emprego do código computacional Hydrus-1D, para diferentes intensidades de precipitação, visando verificar o desempenho desse sistema construtivo na redução do escoamento superficial. Os hidrogramas de saída mostraram-se qualitativamente adequados e quantitativamente coerentes e pode-se concluir que os telhados verdes constituem importantes dispositivos no amortecimento do escoamento superficial oriundo dos telhados, para as condições climáticas da área investigada.

scholarly journals Understanding nitrogen transport in the unsaturated zone with fluctuations in groundwater depth

2021 ◽  
Author(s):  
Jianmin Bian ◽  
Qian Wang ◽  
Siyu Nie ◽  
Hanli Wan ◽  
Juanjuan Wu
Keyword(s):  
Support Vector Machine ◽  
Unsaturated Zone ◽  
Prediction Models ◽  
Groundwater Depth ◽  
Support Vector ◽  
Nitrogen Transport ◽  
Irrigation Area ◽  
Leaching Loss ◽  
The Relationship ◽  
Hydrus 1D

Abstract Fluctuations in groundwater depth play an important role and are often overlooked when considering the transport of nitrogen in the unsaturated zone. To evaluate directly the variation of nitrogen transport due to fluctuations in groundwater depth, the prediction model of groundwater depth and nitrogen transport were combined and applied by least squares support vector machine and Hydrus-1D in the western irrigation area of Jilin in China. The calibration and testing results showed the prediction models were reliable. Considering different groundwater depth, the concentration of nitrogen was affected significantly with a groundwater depth of 3.42–1.71 m, while it was not affected with groundwater depth of 5.48–6.47 m. The total leaching loss of nitrogen gradually increased with the continuous decrease of groundwater depth. Furthermore, the limited groundwater depth of 1.7 m was found to reduce the risk of nitrogen pollution. This paper systematically analyzes the relationship between groundwater depth and nitrogen transport to form appropriate agriculture strategies.

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