scholarly journals The effect of the Danube diversion on the soil moisture conditions in Csallóköz and Szigetköz

2021 ◽  
pp. 1-8
Keyword(s):  
Time Series ◽  
Soil Moisture ◽  
Monitoring Program ◽  
Hydroelectric Power Plant ◽  
Water Levels ◽  
Hydroelectric Power ◽  
Groundwater Levels ◽  
Rooting Zone ◽  
Soil Moisture Storage ◽  
Moisture Conditions

Summary. Following the commissioning of the Gabčíkovo (Bős) hydroelectric power plant in 1992, a monitoring program was launched to assess the agricultural and forestry consequences of the diversion of the Danube into a newly built derivation channel in the Žitný ostrov (Csallóköz) and Szigetköz areas. Prior to the Danube diversion, groundwater played a significant role in the water supply of plants, therefore it is of primary importance to monitor the changes in groundwater levels and soil moisture. Correlation between the groundwater depth and soil moisture time series taken at four measurement points of Szigetköz (T-03, T-04, T-09, T-16) between 1995 and 2012 was analysed. Average and extreme water levels (quartiles 1 and 4) were examined for the 18-year time series, in which 2nd and 3rd quartiles of the groundwater levels were treated together as characteristic water level. It was found that groundwater significantly correlated with soil moisture storage below the rooting zone of field crops. Összefoglalás. A Gabčíkovo (Bős) vízerőművet 1992-ben helyezték üzembe. A dunacsúnyi duzzasztó vize a bősi erőművön átfolyva a Szlovákiában épített vízlevezető csatornából 40 km után tért vissza a korábbi Duna főmederbe. A régi Duna főmederbe emiatt az elterelt szakaszon a korábbi vízmennyiség ötöde került. Minthogy mind a szlovákiai, mind a magyarországi mezőgazdasági és erdőterületek vízellátásában a talajvíz és a dunai árhullámok jelentős szerepet játszottak, 1995-től a Duna-elterelés hatásának felmérésére talajvízszint és talajnedvesség monitoring program indult a Csallóközben és a Szigetközben. A szlovák megfigyelések publikált anyagainak megállapításait és a Szigetközből két szántóföld, egy kaszálórét és egy nyárfaültetvény 1995 és 2012 közötti mérési adatait dolgoztuk fel. A talajvízmélység és a 10 cm-es talajrétegek mért térfogatszázalékos (v.%) nedvességtartalmából számított talajvízkészletek közötti korrelációt számítottuk. A 18 éves idősoron külön vizsgáltuk a jellemző, illetve a szélsőséges vízszintek (1. és 4. kvartilisek) hatását. A jellemző vízszintek hatásának vizsgálatához a talajvízszint értékek 2. és 3. kvartilisét egyben kezeltük. Megállapítottuk, hogy szignifikáns, ill. közel szignifikáns összefüggés csupán az átlagosnál a talajfelszínhez közelebbi (Q1) talajvízmélység esetén volt kimutatható mind a mély (T-03), mind a sekély talajrétegű (T-09) szántóföld 210–300 cm-es, illetve 120–140 cm-es talajszintjében. Vagyis a szántóföldi kultúrák számára az átlagos talajvízmélység nem jelentett vízpótlást. A régi Duna főmederhez közeli kaszálóréten (T-04) a talajvízmélység helyett a dunaremetei medervízszint adatok és a talajnedvességkészlet között még a 140 cm-es mélységben található kavicsos alapkőzet fölötti 20 cm-es talajrétegben sem volt jelentős kapcsolat. A mély talajrétegű (300 cm) erdészeti mérőhely (T-16) talajvízmélység és talajnedvességkészlet korrelációja csupán a 210–300 cm-es talajréteg esetében volt közel szignifikáns. A nyárültetvények fejlődéséhez szükséges éves 700–900 mm vízigény biztosítására emiatt a régi Duna főmederbe engedett többletvízre lenne szükség. A szántóföldi kultúrák terméshozama is elsősorban az adott év csapadékmennyisége és eloszlása szerint alakul. Amennyiben az időjárási feltételek kedvezőtlenek, megoldásként öntözni szükséges. Beszámoltunk továbbá arról, hogy két éve négy mérőhely üzemel, ami a naponta óránként mért 6 órás átlag talajnedvesség-adatokat gyűjti. A folyamatos talajnedvesség-adatgyűjtés célja az időjárás, a növényi vízfelhasználás és a talajvízből történő nedvesítés nyomon követése és a talajvízforgalom-modell leírásának a kontrollja. A közeljövő feladata az évente 12-14 alkalommal az ezeken a mérőhelyeken is gyűjtött kapacitívszondás és a folyamatos nedvességmérési eredmények megfeleltetése, minthogy a bemutatott közel azonos példa mellett több helyen és mélységben időben párhuzamos módon változik ugyan a kétféle érték, azonban akár több, mint 5 v.% különbséggel.

Evaluation of 2018 drought and effectiveness of adaptation measures in the Netherlands

2020 ◽  
Author(s):  
Marjolein H.J. van Huijgevoort ◽  
Janine A. de Wit ◽  
Ruud P. Bartholomeus
Keyword(s):  
Soil Moisture ◽  
The Netherlands ◽  
Capillary Rise ◽  
Hydrological Drought ◽  
Water Levels ◽  
Severe Drought ◽  
Drought Event ◽  
Groundwater Levels ◽  
The Impact

<p>Extreme dry conditions occurred over the summer of 2018 in the Netherlands. This severe drought event led to very low groundwater  and surface water levels. These impacted several sectors like navigation, agriculture, nature and drinking water supply. Especially in the Pleistocene uplands of the Netherlands, the low groundwater levels had a large impact on crop yields and biodiversity in nature areas. Projections show that droughts with this severity will occur more often in the future due to changes in climate. To mitigate the impact of these drought events, water management needs to be altered.</p><p>In this study, we evaluated the 2018 drought event in the sandy regions of the Netherlands and studied which measures could be most effective to mitigate drought impact. We have included meteorological, soil moisture and hydrological drought and the propagation of the drought through these types. Droughts were determined with standardized indices (e.g. Standardized Precipitation Index) and the variable threshold level method. Investigated measures were, for example, higher water levels in ditches, reduced irrigation from groundwater, and increased water conservation in winter. We also studied the timing of these measures to determine the potential for mitigating effects during a drought versus the effectiveness of long term adaptation. The measures were simulated with the agro-hydrological Soil–Water–Atmosphere–Plant (SWAP) model for several areas across the Netherlands for both agricultural fields and nature sites.</p><p>As expected, decreasing irrigation from groundwater reduced the severity of the hydrological drought in the region. Severity of the soil moisture drought also decreased in fields that were never irrigated due to the effects of capillary rise from the groundwater, but, as expected, increased in currently irrigated fields. Increasing the level of a weir in ditches had a relatively small effect on the hydrological drought, provided water was available to sustain higher water levels. This measure is, therefore, better suited as a long term change than as ad hoc measure during a drought. The effectiveness of the measures depended on the characteristics of the regions; for some regions small changes led to increases in groundwater levels for several months, whereas in other regions effects were lost after a few weeks. This study gives insight into the most effective measures to mitigate drought impacts in low-lying sandy regions like the Netherlands.</p>

scholarly journals SOIL pH AND MOISTURE EFFECTS ON VEGETABLE AMARANTH PRODUCTION

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 647e-647
Author(s):  
Bharat P. Singh ◽  
Wayne F. Whitehead
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Soil Ph ◽  
Water Levels ◽  
Plant Parts ◽  
Moisture Effects ◽  
Wide Range ◽  
Significant Difference ◽  
Plant Grown ◽  
Moisture Conditions

The effect of soil moisture and pH levels on the vegetative growth of amaranth were studied in the greenhouse during 1990-91. Three soil pH levels: 4.5, 5.3, and 6.4 and four soil water levels: 3, 6, 12 and 18% (w/w) comprised the treatments of the two studies. The plants grown in pH 6.4 were significantly taller and had greater leaf area than plants grown in pH 5.3 or 4.7 soil. There was a significant decrease in all above ground plant parts with each increase in soil acidity. The top fresh weight of plants grown in 5.6 and 4.7 pH soil were 27% and 73% lower, respectively, than plant grown in 6.4 pH soil. Plant grown in 3% soil water had significantly lower leaf, stem and root fresh weights than other soil water levels. There was no significant difference in the performance of plants grown in 6, 12 or 18% soil water, suggesting that amaranth plant is adapted to a wide range of soil moisture conditions.

scholarly journals Characterising hillslope–stream connectivity with a joint event analysis of stream and groundwater levels

2020 ◽  
Vol 24 (12) ◽  
pp. 5713-5744
Author(s):  
Daniel Beiter ◽  
Markus Weiler ◽  
Theresa Blume
Keyword(s):  
Time Series ◽  
Water Level ◽  
Groundwater Level ◽  
Stream Water ◽  
Water Levels ◽  
Joint Analysis ◽  
Strong Increase ◽  
Groundwater Levels ◽  
The Relationship ◽  
Insight Into

Abstract. Hillslope–stream connectivity controls runoff generation, during events and during baseflow conditions. However, assessing subsurface connectivity is a challenging task, as it occurs in the hidden subsurface domain where water flow can not be easily observed. We therefore investigated if the results of a joint analysis of rainfall event responses of near-stream groundwater levels and stream water levels could serve as a viable proxy for hillslope–stream connectivity. The analysis focuses on the extent of response, correlations, lag times and synchronicity. As a first step, a new data analysis scheme was developed, separating the aspects of (a) response timing and (b) extent of water level change. This provides new perspectives on the relationship between groundwater and stream responses. In a second step we investigated if this analysis can give an indication of hillslope–stream connectivity at the catchment scale. Stream water levels and groundwater levels were measured at five different hillslopes over 5 to 6 years. Using a new detection algorithm, we extracted 706 rainfall response events for subsequent analysis. Carrying out this analysis in two different geological regions (schist and marls) allowed us to test the usefulness of the proxy under different hydrological settings while also providing insight into the geologically driven differences in response behaviour. For rainfall events with low initial groundwater level, groundwater level responses often lag behind the stream with respect to the start of rise and the time of peak. This lag disappears at high antecedent groundwater levels. At low groundwater levels the relationship between groundwater and stream water level responses to rainfall are highly variable, while at high groundwater levels, above a certain threshold, this relationship tends to become more uniform. The same threshold was able to predict increased likelihood for high runoff coefficients, indicating a strong increase in connectivity once the groundwater level threshold was surpassed. The joint analysis of shallow near-stream groundwater and stream water levels provided information on the presence or absence and to a certain extent also on the degree of subsurface hillslope–stream connectivity. The underlying threshold processes were interpreted as transmissivity feedback in the marls and fill-and-spill in the schist. The value of these measurements is high; however, time series of several years and a large number of events are necessary to produce representative results. We also find that locally measured thresholds in groundwater levels can provide insight into the connectivity and event response of the corresponding headwater catchments. If the location of the well is chosen wisely, a single time series of shallow groundwater can indicate if the catchment is in a state of high or low connectivity.

scholarly journals Close co-variation between soil moisture and runoff emerging from multi-catchment data across Europe

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Navid Ghajarnia ◽  
Zahra Kalantari ◽  
René Orth ◽  
Georgia Destouni
Keyword(s):  
Time Series ◽  
Soil Moisture ◽  
Large Scale ◽  
Temperature Anomaly ◽  
Important Variable ◽  
Climatic Variables ◽  
New Approach ◽  
European Climate ◽  
Moisture Conditions

AbstractSoil moisture is an important variable for land-climate and hydrological interactions. To investigate emergent large-scale, long-term interactions between soil moisture and other key hydro-climatic variables (precipitation, actual evapotranspiration, runoff, temperature), we analyze monthly values and anomalies of these variables in 1378 hydrological catchments across Europe over the period 1980–2010. The study distinguishes results for the main European climate regions, and tests how sensitive or robust they are to the use of three alternative observational and re-analysis datasets. Robustly across the European climates and datasets, monthly soil moisture anomalies correlate well with runoff anomalies, and extreme soil moisture and runoff values also largely co-occur. For precipitation, evapotranspiration, and temperature, anomaly correlation and extreme value co-occurrence with soil moisture are overall lower than for runoff. The runoff results indicate a possible new approach to assessing variability and change of large-scale soil moisture conditions by use of long-term time series of monitored catchment-integrating stream discharges.

Development and testing of a remote sensing-based model for estimating groundwater levels in aeolian desert areas of China

2011 ◽  
Vol 91 (1) ◽  
pp. 29-37 ◽  
Author(s):  
Aidi Huo ◽  
Xunhong Chen ◽  
Huike Li ◽  
Ming Hou ◽  
Xiaojing Hou
Keyword(s):  
Remote Sensing ◽  
Soil Moisture ◽  
Groundwater Level ◽  
Remote Sensing Data ◽  
Water Levels ◽  
Desert Area ◽  
Groundwater Levels ◽  
Sensing Data ◽  
Desert Areas ◽  
Regional Groundwater

Huo, A., Chen, X., Li, H., Hou, M. and Hou, X. 2011. Development and testing of a remote sensing-based model for estimating groundwater levels in aeolian desert areas of China. Can. J. Soil Sci. 91: 29–37. Regional groundwater level is an important data set for understanding the relationships between groundwater resources and regional ecological environments. The decline in water table levels leads to vegetation degradation and thus affects the ecological environment. Such a negative effect is especially apparent in the desertification areas. In this study, a remote-sensing based method was proposed to predict the distribution of the regional groundwater level in an aeolian desert area in northern China. The study used the Moderate Resolution Imaging Spectroradiometer (MODIS) remote sensing data and field investigations. Based on field investigation of groundwater level, soil moisture, and other supporting information in the aeolian desert area, as well as the soil moisture distribution derived from the MODIS images, empirical equations describing the relationship between the soil moisture and groundwater level were obtained. The groundwater levels derived using the MODIS image data were verified by groundwater levels measured from 58 wells. The results show that the correlation coefficient between the measured groundwater levels and the remote sensing-based estimated water levels was 0.868, indicating that the error is small and the predictions closely reflect the real water levels. This model can be used to predict groundwater levels in aeolian desert areas based on remote sensing data sets.

scholarly journals Remote Sensing-Informed Zonation for Understanding Snow, Plant and Soil Moisture Dynamics within a Mountain Ecosystem

2020 ◽  
Vol 12 (17) ◽  
pp. 2733 ◽  
Author(s):  
Jashvina Devadoss ◽  
Nicola Falco ◽  
Baptiste Dafflon ◽  
Yuxin Wu ◽  
Maya Franklin ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Time Series ◽  
Soil Moisture ◽  
High Resolution ◽  
Time Lapse ◽  
Resolution Time ◽  
Topographic Wetness Index ◽  
Wetness Index ◽  
Plant Dynamics ◽  
Moisture Conditions

In the headwater catchments of the Rocky Mountains, plant productivity and its dynamics are largely dependent upon water availability, which is influenced by changing snowmelt dynamics associated with climate change. Understanding and quantifying the interactions between snow, plants and soil moisture is challenging, since these interactions are highly heterogeneous in mountainous terrain, particularly as they are influenced by microtopography within a hillslope. Recent advances in satellite remote sensing have created an opportunity for monitoring snow and plant dynamics at high spatiotemporal resolutions that can capture microtopographic effects. In this study, we investigate the relationships among topography, snowmelt, soil moisture and plant dynamics in the East River watershed, Crested Butte, Colorado, based on a time series of 3-meter resolution PlanetScope normalized difference vegetation index (NDVI) images. To make use of a large volume of high-resolution time-lapse images (17 images total), we use unsupervised machine learning methods to reduce the dimensionality of the time lapse images by identifying spatial zones that have characteristic NDVI time series. We hypothesize that each zone represents a set of similar snowmelt and plant dynamics that differ from other identified zones and that these zones are associated with key topographic features, plant species and soil moisture. We compare different distance measures (Ward and complete linkage) to understand the effects of their influence on the zonation map. Results show that the identified zones are associated with particular microtopographic features; highly productive zones are associated with low slopes and high topographic wetness index, in contrast with zones of low productivity, which are associated with high slopes and low topographic wetness index. The zones also correspond to particular plant species distributions; higher forb coverage is associated with zones characterized by higher peak productivity combined with rapid senescence in low moisture conditions, while higher sagebrush coverage is associated with low productivity and similar senescence patterns between high and low moisture conditions. In addition, soil moisture probe and sensor data confirm that each zone has a unique soil moisture distribution. This cluster-based analysis can tractably analyze high-resolution time-lapse images to examine plant-soil-snow interactions, guide sampling and sensor placements and identify areas likely vulnerable to ecological change in the future.

scholarly journals Characterizing hillslope-stream connectivity with a joint event analysis of stream and groundwater levels

2020 ◽  
Author(s):  
Daniel Beiter ◽  
Markus Weiler ◽  
Theresa Blume
Keyword(s):  
Time Series ◽  
Water Level ◽  
Groundwater Level ◽  
Stream Water ◽  
Water Levels ◽  
Joint Analysis ◽  
Catchment Scale ◽  
Groundwater Levels ◽  
The Relationship ◽  
Insight Into

Abstract. Hillslope-stream connectivity controls runoff generation, both during events and baseflow conditions. However, assessing subsurface connectivity is a challenging task, as it occurs in the hidden subsurface domain where water flow cannot be easily observed. We therefore investigated if the results of a joint analysis of rainfall event responses of near-stream groundwater levels and stream water levels could serve as a viable proxy for hillslope-stream connectivity. The analysis focuses on the extent of response, correlations, lag times and synchronicity. A newly developed data analysis scheme of separating the aspects of (a) response timing and (b) extent of water level change provides new perspectives on the relationship between groundwater and stream responses. In a second step we investigated if this analysis can give an indication of hillslope-stream connectivity at the catchment scale. Stream- and groundwater levels were measured at five different hillslopes over 5 to 6 years. Using a new detection algorithm we extracted 706 rainfall response events for subsequent analysis. Carrying out this analysis in two different geological regions (schist and marls) allowed us to test the usefulness of the proxy under different hydrological settings while also providing insight into the geologically-driven differences in response behaviour. For rainfall events with low initial groundwater level, groundwater level responses often lag behind the stream with respect to the start of rise and the time of peak. This lag disappears at high antecedent groundwater levels. At low groundwater levels the relationship between groundwater and stream water level responses to rainfall are highly variable, while at high groundwater levels, above a certain threshold, this relationship tends to become more uniform. The same threshold was able to predict increased likelihood for high runoff coefficients, indicating a strong increase in connectivity once the groundwater level threshold was surpassed. The joint analysis of shallow near-stream groundwater and stream water levels provided information on the presence or absence and to a certain extent also on the degree of subsurface hillslope-stream connectivity. The underlying threshold processes were interpreted as transmissivity feedback in the marls and fill-and-spill in the schist. The value of these measurements is high, however, time series of several years and a large number of events are necessary to produce representative results. We also find that locally measured thresholds in groundwater levels can provide insight into catchment-scale connectivity and event response. If the location of the well is chosen wisely, a single time series of shallow groundwater can indicate if the catchment is in a state of high or low connectivity.

Soil moisture conditions and pine failure at Waarre, near Port Campbell, Victoria

1962 ◽  
Vol 13 (3) ◽  
pp. 426 ◽  
Author(s):  
T Poutsma ◽  
KJ Simpfendorfer
Keyword(s):  
Soil Moisture ◽  
Ground Water ◽  
Correlation Coefficient ◽  
Pinus Radiata ◽  
Free Water ◽  
Water Levels ◽  
Lateral Movement ◽  
Monterey Pine ◽  
Shallow Wells ◽  
Moisture Conditions

The pines in the Forests Commission plantation at Waarre, near Port Campbell in Victoria, are marked by large and widespread differences in vigour, and in some cases even by virtual failure. To investigate this condition the presence of and changes in free water levels in the soils were followed at 16 sites on the plantation. This was done by means of shallow wells 30 in. deep, and piezometers sunk to a depth of 5½ ft. Observations extended over 28 months. The results showed that surface waterlogging is widely present on the plantation. This surface waterlogging is seasonal, and it varies in severity from year to year in accordance with the rainfall. "Free" ground-water is absent from nearly all the deep subsoils. The vigour of the pine cover was found to vary significantly with the degree of surface waterlogging. For Monterey pine (Pinus radiata D. Don) the correlation coefficient for nine sites was 0.82**, and for maritime pine (P. pinaster Ait.) the correlation coefficient for six sites was 0.81*. This relationship appears to be modified by the lateral movement of free water through the surface horizons. Nutrient trials have also shown a slow but marked response to additions of superphosphate.

Improving hydrological model performance by incorporating dynamic variability of parameters

2020 ◽  
Author(s):  
Lakshmi Girija ◽  
Sudheer Kulamullaparambathu
Keyword(s):  
Time Series ◽  
Soil Moisture ◽  
Model Performance ◽  
Hydrologic Models ◽  
Antecedent Precipitation ◽  
Process Representation ◽  
Time Period ◽  
Dry Spells ◽  
Daily Change ◽  
Moisture Conditions

<p>Extensive research is being carried out in developing new calibration procedures for improving the efficacy of hydrologic models. Considering the simulation period into separate wet and dry periods, and performing discrete calibration on each of them has resulted in improvement in model performance, especially during dry periods. In this procedure, it is envisaged that by splitting the time period into wet and dry, the temporal variability of soil moisture, which play a major role in maintaining the water balance of the catchment, is accounted. The discretely calibrated data is then recombined to form the entire time series. However, while recombining the discretely calibrated time periods, the physics of the hydrological processes, at the time of transition from one period to the other, may show abrupt variations. In addition, the short spells of wetness and dryness within this partitioned period, which influences the soil saturation, may not get effectively simulated. This study proposes division of simulation period into wet and dry spells considering the state of saturation of the watershed. This is achieved by clustering the time series of the data using the antecedent precipitation and the soil moisture conditions. A supervised Gustafson-Kessel clustering technique is employed for the same. Subsequently, a relationship between the precipitation, the daily change in soil moisture and a selected model parameter is established for all the cluster transitions and incorporated into the model structure. The proposed methodology is tested using a grid based model with six parameters, on Riesel watershed, Texas, USA. The results indicate that clusters formed are unique, with no fixed duration and no repetitive patterns across the entire simulation period. For preliminary analysis, only one parameter is dynamically varied depending on the incoming rainfall. The performance of the refined model (NSE = 0.85) over the conventional static parameter model (NSE = 0.83), though not significant, indicate that better process representation can aid in improving model simulations. It is noted that this method eliminates the abrupt variation of soil moisture across the wet and dry periods, as the simulation is continuous.</p>

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