Modelling the Hydrologic Regime of Arid Inland Wetlands: Non-linear Relationship Between Root-uptakes of Water and Underground Water Table

2021 ◽  
Author(s):  
Lin Li ◽  
Hu Liu ◽  
Yang Yu ◽  
Wenzhi Zhao
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Soil Moisture ◽  
Water Table ◽  
Land Use Changes ◽  
Northwestern China ◽  
Wetland Ecosystem ◽  
Soil Moisture Dynamics ◽  
Inland Wetlands ◽  
Moisture Dynamics

<p><strong>Abstract: </strong>Wetlands remaining in the arid inland river landscapes of northwestern China suffer degradation and their resilience and ability to continue functioning under hydrologic and land use changes resulting from climate change may be significantly inhibited. Information on the desert-oasis wetlands, however, is sparse and knowledge of how ecological functioning and resilience may change under climate change and water-resource management is still lacking. Research in oasis wetland areas of the Northwestern China identified linkages between subsurface flow, plant transpiration, and water levels. In this study, we present an ecohydrological analysis of the energy and water balance in the wetland ecosystem. A process-based stochastic soil moisture model developed for groundwater-dependent ecosystems was employed to modelling the interactions between rainfall, water table fluctuations, soil moisture dynamics, and vegetation, and to investigate the ecohydrology of arid inland wetlands system. Field measured groundwater levels, vertical soil moisture profiles, soil water potentials, and root biomass allocation and transpiration of pioneer species in the wetlands were used to calibrate and validate the stochastic model. The parameterized model was then running to simulate the probability distributions of soil moisture and root water uptake, and quantitative descript the vegetation–water table–soil moisture interplay in the hypothesized scenarios of future. Our analysis suggested the increasing rates of water extraction and regulation of hydrologic processes, coupled with destruction of natural vegetation, and climate change, are jeopardizing the future persistence of wetlands and the ecological and socio-economic functions they support. To understand how climate change will impact on the ecohydrological functioning of wetlands, both hydrological and land use changes need to be considered in future works.</p><p><strong>Keywords: </strong>Wetland ecosystem, groundwater, soil moisture dynamics, water balances, Heihe River Basin</p>

scholarly journals A signature-based approach to quantify soil moisture dynamics under contrasting land-uses

2021 ◽  
Author(s):  
Ryoko Araki ◽  
Flora Branger ◽  
Inge Wiekenkamp ◽  
Hilary McMillan
Keyword(s):  
Land Use ◽  
Time Series ◽  
Soil Moisture ◽  
Shallow Groundwater ◽  
Storm Event ◽  
Land Uses ◽  
Soil Moisture Dynamics ◽  
Land Use Types ◽  
Event Based ◽  
Moisture Dynamics

Soil moisture signatures provide a promising solution to overcome the difficulty of evaluating soil moisture dynamics in hydrologic models. Soil moisture signatures are metrics that represent catchment dynamics extracted from time series of data and enable process-based model evaluations. To date, soil moisture signatures have been tested only under limited land-use types. In this study, we explore soil moisture signatures’ ability to discriminate different dynamics among contrasting land-uses. We applied a set of nine soil moisture signatures to datasets from six in-situ soil moisture networks worldwide. The dataset covers a range of land-use types, including forested and deforested areas, shallow groundwater areas, wetlands, housing areas, grazed areas, and cropland areas. These signatures characterize soil moisture dynamics at three temporal scales: event, seasonal, and time-series scales. Statistical and visual assessment of extracted signatures showed that (1) storm event-based signatures can distinguish different dynamics for most land-uses, (2) season-based signatures are useful to distinguish different dynamics for some types of land-uses (forested vs. deforested area, greenspace vs. housing area, and deep vs. shallow groundwater area), (3) timeseries-based signatures can distinguish different dynamics for some types of land-uses (forested vs. deforested area, deep vs. shallow groundwater area, non-wetland vs. wetland area, and ungrazed vs. grazed area). We compared signature-based process interpretations against literature knowledge: event-based and time series-based signatures were generally matched well with previous process understandings from literature, but season-based signatures did not. This study demonstrates the best practices of extracting soil moisture signatures under various land-use and climate environments and applying signatures for model evaluations.

Transient soil-moisture dynamics and climate change in Mediterranean ecosystems

2008 ◽  
Vol 44 (11) ◽  
Author(s):  
F. Viola ◽  
E. Daly ◽  
G. Vico ◽  
M. Cannarozzo ◽  
A. Porporato
Keyword(s):  
Climate Change ◽  
Soil Moisture ◽  
Mediterranean Ecosystems ◽  
Soil Moisture Dynamics ◽  
Moisture Dynamics

Evaluation of land cover effects on soil-moisture dynamics: adaptation measures from the territory (Bidasoa catchment, Western Pyrenees).

2020 ◽  
Author(s):  
María Valiente ◽  
Ane Zabaleta ◽  
Maite Meaurio ◽  
Jesus A. Uriarte ◽  
Iñaki Antigüedad
Keyword(s):  
Climate Change ◽  
Soil Moisture ◽  
Land Cover ◽  
Soil Properties ◽  
Hydrological Modelling ◽  
Soil Conditions ◽  
Adaptation Measures ◽  
Soil Moisture Dynamics ◽  
Land Covers ◽  
Moisture Dynamics

<p>The Pyrenees mountain range is the main source of water resources for a large surrounding region, extending from the Atlantic to the Mediterranean. This area is particularly vulnerable to the consequences of climate change. The PIRAGUA project (Interreg-POCTEFA) evaluates the components of the hydrological cycle in the Pyrenees, with the central objective of improving the adaptation of territories to climate change. One of its tasks focuses on the analysis of the effect that land cover and associated soil properties have on different hydrological services. Indeed, land use and its management directly affect soil hydrology, which is a key factor in streamflow temporal distribution. A better understanding of the water-soil-vegetation system is essential for a reliable hydrological modelling which results should be considered in adaptation strategies to climate change.</p><p>To this aim, chemical and physical characterization of soil properties is being conducted at the 681 km<sup>2</sup> humid Bidasoa catchment (Pyrenees). In order to understand the soil-moisture dynamics, a monitoring network was established in July 2019 in a 0.4 km<sup>2</sup> experimental site within the catchment. Four soil-moisture stations and a meteorological one were installed within the same geological setting, same rainfall conditions and similar soil texture characteristics (silt-loamy texture and about one meter deep), but different land covers (pine forest, oak forest, grassland and fernery). Continuous soil-moisture data obtained to date show that upper soil layers (0-20 cm) are deeply influenced by top vegetation cover. Grassland has the highest soil-moisture variations, ranging from 16.2 to 36.6 %, as they closely mirror precipitation patterns. Pine and oak forests present similar variation trend, varying from 33.9 to 42.8 % and from 35.3 to 41.9 %, respectively. Soil-moisture at fernery goes from 30.5 to 36 %. Minimum soil-moisture values coincide in all plots with the end of the dry period (end of September). Maximum values, occurring during very heavy and continuous precipitation in November (647 mm registered from 1 to 24 November), are considered as a proxy for saturated soil conditions. In all the plots, fluctuations in soil-moisture diminish significantly with increasing soil depth. However, considerable differences are found in the vertical soil-moisture profile across land covers. In both forest plots, a decreasing trend of soil-moisture within the profile is observed, while grassland and fernery show an increasing trend. Preliminary results show that soil water infiltration is different among different land covers, which give some insight into the hydrological functionality of soil under different vegetation types. Longer records of soil-moisture dynamics in the area would contribute to better assess the linkages between water, soil and vegetation and, in turn, to improve hydrological modelling in humid mountainous areas. This knowledge is necessary for a better consideration of the adaptation measures that should be taken from the territory.</p>

scholarly journals Climatic expression of rainfall on soil moisture dynamics in drylands

2021 ◽  
Author(s):  
Isaac Kipkemoi ◽  
Katerina Michaelides ◽  
Rafael Rosolem ◽  
Michael Bliss Singer
Keyword(s):  
Climate Change ◽  
Soil Moisture ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Water Scarcity ◽  
Rainfall Intensity ◽  
Precipitation Data ◽  
Soil Moisture Dynamics ◽  
Moisture Dynamics

Abstract. In drylands, characterised by water scarcity and frequent meteorological droughts, knowledge of soil moisture dynamics and its drivers (evapotranspiration, soil physical properties and the timing and sequencing of precipitation events) is fundamental to understanding changes in water availability to plants and human society, especially under a nonstationary climate. Given the episodic and stochastic nature of rainfall in drylands and the limited availability of data in these regions, we sought to explore what effects the temporal resolution of precipitation data has on soil moisture and how soil moisture distributions might evolve under different scenarios of climate change. Such information is critical for anticipating the impact of a changing climate on dryland communities across the globe, especially those that depend on rainfed agriculture and groundwater wells for drinking water for humans and livestock. A major challenge to understanding soil moisture in response to climate is the availability of precipitation datasets for dryland regions across the globe. Gridded precipitation data may only be available for daily or weekly time periods, even though rainstorms in drylands often occur on much shorter time scales, but it is currently unknown how this timescale mismatch might affect our understanding of soil moisture. Numerical modelling enables retrodiction or prediction of how climate translates into dynamically evolving moisture within the soil profile. It can be used to explore how climate data at different temporal resolutions affect these soil moisture dynamics, as well as to explore the influence of shifts in rainfall characteristics (e.g., storm intensity) under potential scenarios of climate change. This study uses Hydrus 1-D, to investigate the dynamics of soil moisture over a period of decades in response to the same underlying rainfall data resolved at hourly, daily, and weekly resolutions, as well as to step changes in rainfall delivery, which is expected under a warming atmosphere. We parameterised the model using rainfall, evaporative demand, and soils data from the semi-arid Walnut Gulch Experimental Watershed (WGEW) in SE Arizona, but we present the results as a generalized study of how rainfall resolution and shifts in rainfall intensity may affect dryland soil moisture at different depths. Our results indicate that hourly or better rainfall resolution captures the dynamics of soil moisture in drylands, and that critical information on soil water content, moisture availability to vegetation, actual evapotranspiration, and deep percolation of infiltrated water is lost when soil moisture modelling is driven by rainfall data at coarser temporal resolutions (daily, weekly). We further show that modest changes in rainfall intensity dramatically shift soil water content and the overall water balance. These findings are relevant to the prediction of soil moisture for crop yield forecasts, for adaptation to climate-related risks, and for anticipating the challenges of water scarcity and food insecurity in dryland communities around the globe, where available datasets are of low spatial and temporal resolution.

scholarly journals A signature-based approach to quantify soil moisture dynamics under contrasting land-uses

2021 ◽  
Author(s):  
Ryoko Araki ◽  
Flora Branger ◽  
Inge Wiekenkamp ◽  
Hilary McMillan
Keyword(s):  
Land Use ◽  
Soil Moisture ◽  
Urban Areas ◽  
Shallow Groundwater ◽  
Land Uses ◽  
Catchment Scale ◽  
Soil Moisture Dynamics ◽  
Land Use Types ◽  
Event Based ◽  
Moisture Dynamics

Soil moisture signatures provide a promising solution to overcome the difficulty of evaluating soil moisture dynamics in hydrologic models. Soil moisture signatures are metrics that quantify the dynamic aspects of soil moisture timeseries and enable process-based model evaluations. To date, soil moisture signatures have been tested only under limited land-use types. In this study, we explore soil moisture signatures’ ability to discriminate different dynamics among contrasting land-uses. We applied a set of nine soil moisture signatures to datasets from six in-situ soil moisture networks worldwide. The dataset covered a range of land-use types, including forested and deforested areas, shallow groundwater areas, wetlands, urban areas, grazed areas, and cropland areas. Our set of signatures characterized soil moisture dynamics at three temporal scales: event, season, and a complete timeseries. Statistical assessment of extracted signatures showed that (1) event-based signatures can distinguish different dynamics for all the land-uses, (2) season-based signatures can distinguish different dynamics for some types of land-uses (deforested vs. forested, urban vs. greenspace, and cropped vs. grazed vs. grassland contrasts), (3) timeseries-based signatures can distinguish different dynamics for some types of land-uses (deforested vs. forested, urban vs. greenspace, shallow vs. deep groundwater, wetland vs. non-wetland, and cropped vs. grazed vs. grassland contrasts). Further, we compared signature-based process interpretations against literature knowledge; event-based and timeseries-based signatures generally matched well with previous process understandings from literature, but season-based signatures did not. This study will be a useful guideline for understanding how catchment-scale soil moisture dynamics in various land-uses can be described using a standardized set of hydrologically relevant metrics.

Soil moisture dynamics of different land-cover types in the blacksoil regions of China

2009 ◽  
Vol 17 (2) ◽  
pp. 256-260 ◽  
Author(s):  
Feng WANG ◽  
Shu-Qi WANG ◽  
Xiao-Zeng HAN ◽  
Feng-Xian WANG ◽  
Ke-Qiang ZHANG
Keyword(s):  
Soil Moisture ◽  
Land Cover ◽  
Soil Moisture Dynamics ◽  
Land Cover Types ◽  
Moisture Dynamics

scholarly journals Changes in Coastal Agricultural Land Use in Response to Climate Change: An Assessment Using Satellite Remote Sensing and Household Survey Data in Tien Hai District, Thai Binh Province, Vietnam

Land ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 627
Author(s):  
Duong H. Nong ◽  
An T. Ngo ◽  
Hoa P. T. Nguyen ◽  
Thuy T. Nguyen ◽  
Lan T. Nguyen ◽  
...  
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Agricultural Land ◽  
Land Use Changes ◽  
Management Strategies ◽  
Household Survey ◽  
Extreme Weather Events ◽  
Agricultural Land Use ◽  
Landsat 8 ◽  
Land Uses

We analyzed the agricultural land-use changes in the coastal areas of Tien Hai district, Thai Binh province, in 2005, 2010, 2015, and 2020, using Landsat 5 and Landsat 8 data. We used the object-oriented classification method with the maximum likelihood algorithm to classify six types of land uses. The series of land-use maps we produced had an overall accuracy of more than 80%. We then conducted a spatial analysis of the 5-year land-use change using ArcGIS software. In addition, we surveyed 150 farm households using a structured questionnaire regarding the impacts of climate change on agricultural productivity and land uses, as well as farmers’ adaptation and responses. The results showed that from 2005 to 2020, cropland decreased, while aquaculture land and forest land increased. We observed that the most remarkable decreases were in the area of rice (485.58 ha), the area of perennial crops (109.7 ha), and the area of non-agricultural land (747.35 ha). The area of land used for aquaculture and forest increased by 566.88 ha and 772.60 ha, respectively. We found that the manifestations of climate change, such as extreme weather events, saltwater intrusion, drought, and floods, have had a profound impact on agricultural production and land uses in the district, especially for annual crops and aquaculture. The results provide useful information for state authorities to design land-management strategies and solutions that are economic and effective in adapting to climate change.

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