scholarly journals Impact of Arable Land to Grassland Conversion on the Vegetation-period Water Balance of a Small Agricultural Catchment (Němčický Stream)

2010 ◽  
Vol 5 (No. 4) ◽  
pp. 128-138 ◽  
Author(s):  
P. Kovář ◽  
D. Vaššová

This paper presents results of decadal (10-day) water balance simulations for the vegetation periods (April to October) of 2001 (normal year), 2002 (wet year) and 2003 (dry year) in the Němčick&yacute; Stream experimental catchment (3.52 km<sup>2</sup>). The catchment is a typical agricultural area with a large extent of arable land. This paper shows that the model used (WBCM) is capable of reliably simulating decadal water balance components for the actual land use. The same model is then used to estimate water balance changes brought about when 10% of arable land has been transformed into permanent grassland. It is shown that this land use change results in a pronounced reduction of surface runoff and an increase in subsurface storage over the vegetation periods of all three years. The vegetation period groundwater runoff was only enhanced in the wet year, while the total runoff was reduced in all three years.&nbsp;

2007 ◽  
Vol 4 (6) ◽  
pp. 4265-4295 ◽  
Author(s):  
J. Dams ◽  
S. T. Woldeamlak ◽  
O. Batelaan

Abstract. Land-use change and climate change, along with groundwater pumping are frequently indicated to be the main human-induced factors influencing the groundwater system. Up till now, research has mainly been focusing on the effect of the water quality of these human-induced changes on the groundwater system, often neglecting changes in quantity. The focus in this study is on the impact of land-use changes in the near future, from 2000 until 2020, on the groundwater quantity and the general hydrologic balance of a sub-catchment of the Kleine Nete, Belgium. This study tests a new methodology which involves coupling a land-use change model with a water balance model and a groundwater model. The future land-use is modelled with the CLUE-S model. Four scenarios (A1, A2, B1 and B2) based on the Special Report on Emission Scenarios (SRES) are used for the land-use modelling. Water balance components, groundwater level and baseflow are simulated using the WetSpass model in conjunction with a MODFLOW groundwater model. Results show that the average recharge slowly decreases for all scenarios, the decreases are 2.9, 1.6, 1.8 and 0.8% for respectively scenario A1, A2, B1 and B2. The predicted reduction in recharge results in a small decrease of the average groundwater level, ranging from 2.5 cm for scenario A1 to 0.9 cm for scenario B2, and a reduction of the total baseflow with maximum 2.3% and minimum 0.7% respectively for scenario A1 and B2. Although these average values do not indicate significant changes for the groundwater system, spatial analysis of the changes shows the changes are concentrated in the neighbourhood of the major cities in the study areas. It is therefore important for spatial managers to take the groundwater system into account for reducing the negative impacts of land-use and climate change as much as possible.


Agrologia ◽  
2018 ◽  
Vol 1 (1) ◽  
Author(s):  
Semuel Laimeheriwa

This research was conducted to estimate the values of parameters which described the physical characteristics of catchments area and monthly water balance components, and understand the sensitivity of the water balance components to change in the parameter value due to the physical changes occurring in Way Pia catchments area, Ceram Island.  The method used involved calculation of the regional water balance in the current time (normal) and during the time of land use change, using an evapoclimatonomy model. The main model inputs were monthly rainfall, global radiation and run off. Analyses of data were conducted with five steps as follows : (1) mathematical formulation of the evapoclimatonomy model, (2) algorithm formation and transfer to computer code, (3) establishment of parameters and calibration, (4) validation of model, and (5) experimentation of model. The current physical conditions of Way Pia catchments area were characterized by: average of parameter value of albedo, a = 0,16; rainfall threshold, Pn = 100 mm; surface run off ratio, np = 0,23; evapority, ep = 0,42; measure of soil water loss from sub surface, vN = 0,12; and measure of evapotranspiration of soil water from sub surface, vE = 0,20. Model output of the current water balance consisted of  annual value of soil moisture, m = 272 mm; total evapotranspiration, E = 1393 mm, and total run off, N = 920 mm. The land use change  in the form of land clearing will increase the parameter values of a and np, which affect on increasing of direct run off (N') of 13% as compared to current conditions.


2008 ◽  
Vol 12 (6) ◽  
pp. 1369-1385 ◽  
Author(s):  
J. Dams ◽  
S. T. Woldeamlak ◽  
O. Batelaan

Abstract. Land-use changes are frequently indicated to be one of the main human-induced factors influencing the groundwater system. For land-use change, groundwater research has mainly focused on the change in water quality thereby neglecting changes in quantity. The objective of this paper is to assess the impact of land-use changes, from 2000 until 2020, on the hydrological balance and in particular on groundwater quantity, as results from a case study in the Kleine Nete basin, Belgium. New is that this study tests a methodology, which couples a land-use change model with a water balance and a steady-state groundwater model. Four future land-use scenarios (A1, A2, B1 and B2) based on the Special Report on Emission Scenarios (SRES) are modelled with the CLUE-S model. Water balance components, groundwater level and baseflow are simulated using the WetSpass model in conjunction with a steady-state MODFLOW groundwater flow model. Results show that the average recharge decreases with 2.9, 1.6, 1.8 and 0.8% for scenario A1, A2, B1 and B2, respectively, over the 20 covered years. The predicted reduction in recharge results in a small decrease of the average groundwater level in the basin, ranging from 2.5 cm for scenario A1 to 0.9 cm for scenario B2, and a reduction of the baseflow with maximum 2.3% and minimum 0.7% for scenario A1 and B2, respectively. Although these averages appear to indicate small changes in the groundwater system, spatial analysis shows that much larger changes are located near the major cities in the study area. Hence, spatial planning should take better account of effects of land-use change on the groundwater system and define mitigating actions for reducing the negative impacts of land-use change.


2010 ◽  
Vol 7 (4) ◽  
pp. 5851-5893 ◽  
Author(s):  
L. M. Mango ◽  
A. M. Melesse ◽  
M. E. McClain ◽  
D. Gann ◽  
S. G. Setegn

Abstract. With the flow of the Mara River becoming increasingly erratic especially in the upper reaches, attention has been directed to land use change as the major cause of this problem. The semi-distributed hydrological model Soil and Water Assessment Tool (SWAT) and Landsat imagery were utilized in the upper Mara River Basin in order to 1) map existing field scale land use practices in order to determine their impact 2) determine the impacts of land use change on water flux; and 3) determine the impacts of rainfall (0%, ±10% and ±20%) and air temperature variations (0% and +5%) based on the Intergovernmental Panel on Climate Change projections on the water flux of the upper Mara River. This study found that the different scenarios impacted on the water balance components differently. Land use changes resulted in a slightly more erratic discharge while rainfall and air temperature changes had a more predictable impact on the discharge and water balance components. These findings demonstrate that the model results show the flow was more sensitive to the rainfall changes than land use changes. It was also shown that land use changes can reduce dry season flow which is the most important problem in the basin. The model shows also deforestation in the Mau Forest increased the peak flows which can also lead to high sediment loading in the Mara River. The effect of the land use and climate change scenarios on the sediment and water quality of the river needs a thorough understanding of the sediment transport processes in addition to observed sediment and water quality data for validation of modeling results.


Land ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 749
Author(s):  
Leonardo Bianchini ◽  
Gianluca Egidi ◽  
Ahmed Alhuseen ◽  
Adele Sateriano ◽  
Sirio Cividino ◽  
...  

The spatial mismatch between population growth and settlement expansion is at the base of current models of urban growth. Empirical evidence is increasingly required to inform planning measures promoting urban containment in the context of a stable (or declining) population. In these regards, per-capita indicators of land-use change can be adopted with the aim at evaluating long-term sustainability of urbanization processes. The present study assesses spatial variations in per-capita indicators of land-use change in Rome, Central Italy, at five years (1949, 1974, 1999, 2008, and 2016) with the final objective of quantifying the mismatch between urban expansion and population growth. Originally specialized in agricultural productions, Rome’s metropolitan area is a paradigmatic example of dispersed urban expansion in the Mediterranean basin. By considering multiple land-use dynamics, per-capita indicators of landscape change delineated three distinctive waves of growth corresponding with urbanization, suburbanization, and a more mixed stage with counter-urbanization and re-urbanization impulses. By reflecting different socioeconomic contexts on a local scale, urban fabric and forests were identified as the ‘winner’ classes, expanding homogeneously over time at the expense of cropland. Agricultural landscapes experienced a more heterogeneous trend with arable land and pastures declining systematically and more fragmented land classes (e.g., vineyards and olive groves) displaying stable (or slightly increasing) trends. The continuous reduction of per-capita surface area of cropland that’s supports a reduced production base, which is now insufficient to satisfy the rising demand for fresh food at the metropolitan scale, indicates the unsustainability of the current development in Rome and more generally in the whole Mediterranean basin, a region specialized traditionally in (proximity) agricultural productions.


2021 ◽  
Vol 13 (4) ◽  
pp. 647
Author(s):  
Fan Sun ◽  
Yi Wang ◽  
Yaning Chen ◽  
Yupeng Li ◽  
Qifei Zhang ◽  
...  

The desert-oasis ecotone, as a crucial natural barrier, maintains the stability of oasis agricultural production and protects oasis habitat security. This paper investigates the dynamic evolution of the desert-oasis ecotone in the Tarim River Basin and predicts the near-future land-use change in the desert-oasis ecotone using the cellular automata–Markov (CA-Markov) model. Results indicate that the overall area of the desert-oasis ecotone shows a shrinking trend (from 67,642 km2 in 1990 to 46,613 km2 in 2015) and the land-use change within the desert-oasis ecotone is mainly manifested by the conversion of a large amount of forest and grass area into arable land. The increasing demand for arable land for groundwater has led to a decline in the groundwater level, which is an important reason for the habitat deterioration in the desert-oasis ecotone. The rising temperature and drought have further exacerbated this trend. Assuming the current trend in development without intervention, the CA-Markov model predicts that by 2030, there will be an additional 1566 km2 of arable land and a reduction of 1151 km2 in forested area and grassland within the desert-oasis ecotone, which will inevitably further weaken the ecological barrier role of the desert-oasis ecotone and trigger a growing ecological crisis.


2021 ◽  
Vol 21 (3) ◽  
Author(s):  
Susanne Rolinski ◽  
Alexander V. Prishchepov ◽  
Georg Guggenberger ◽  
Norbert Bischoff ◽  
Irina Kurganova ◽  
...  

AbstractChanges in land use and climate are the main drivers of change in soil organic matter contents. We investigated the impact of the largest policy-induced land conversion to arable land, the Virgin Lands Campaign (VLC), from 1954 to 1963, of the massive cropland abandonment after 1990 and of climate change on soil organic carbon (SOC) stocks in steppes of Russia and Kazakhstan. We simulated carbon budgets from the pre-VLC period (1900) until 2100 using a dynamic vegetation model to assess the impacts of observed land-use change as well as future climate and land-use change scenarios. The simulations suggest for the entire VLC region (266 million hectares) that the historic cropland expansion resulted in emissions of 1.6⋅ 1015 g (= 1.6 Pg) carbon between 1950 and 1965 compared to 0.6 Pg in a scenario without the expansion. From 1990 to 2100, climate change alone is projected to cause emissions of about 1.8 (± 1.1) Pg carbon. Hypothetical recultivation of the cropland that has been abandoned after the fall of the Soviet Union until 2050 may cause emissions of 3.5 (± 0.9) Pg carbon until 2100, whereas the abandonment of all cropland until 2050 would lead to sequestration of 1.8 (± 1.2) Pg carbon. For the climate scenarios based on SRES (Special Report on Emission Scenarios) emission pathways, SOC declined only moderately for constant land use but substantially with further cropland expansion. The variation of SOC in response to the climate scenarios was smaller than that in response to the land-use scenarios. This suggests that the effects of land-use change on SOC dynamics may become as relevant as those of future climate change in the Eurasian steppes.


Water ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1433
Author(s):  
Navneet Kumar ◽  
Asia Khamzina ◽  
Patrick Knöfel ◽  
John P. A. Lamers ◽  
Bernhard Tischbein

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.


2004 ◽  
Vol 8 (5) ◽  
pp. 903-922 ◽  
Author(s):  
M. Bari ◽  
K. R. J. Smettem

Abstract. A conceptual water balance model is presented to represent changes in monthly water balance following land use changes. Monthly rainfall–runoff, groundwater and soil moisture data from four experimental catchments in Western Australia have been analysed. Two of these catchments, "Ernies" (control, fully forested) and "Lemon" (54% cleared) are in a zone of mean annual rainfall of 725 mm, while "Salmon" (control, fully forested) and "Wights" (100% cleared) are in a zone with mean annual rainfall of 1125 mm. At the Salmon forested control catchment, streamflow comprises surface runoff, base flow and interflow components. In the Wights catchment, cleared of native forest for pasture development, all three components increased, groundwater levels rose significantly and stream zone saturated area increased from 1% to 15% of the catchment area. It took seven years after clearing for the rainfall–runoff generation process to stabilise in 1984. At the Ernies forested control catchment, the permanent groundwater system is 20 m below the stream bed and so does not contribute to streamflow. Following partial clearing of forest in the Lemon catchment, groundwater rose steadily and reached the stream bed by 1987. The streamflow increased in two phases: (i) immediately after clearing due to reduced evapotranspiration, and (ii) through an increase in the groundwater-induced stream zone saturated area after 1987. After analysing all the data available, a conceptual monthly model was created, comprising four inter-connecting stores: (i) an upper zone unsaturated store, (ii) a transient stream zone store, (ii) a lower zone unsaturated store and (iv) a saturated groundwater store. Data such as rooting depth, Leaf Area Index, soil porosity, profile thickness, depth to groundwater, stream length and surface slope were incorporated into the model as a priori defined attributes. The catchment average values for different stores were determined through matching observed and predicted monthly hydrographs. The observed and predicted monthly runoff for all catchments matched well with coefficients of determination (R2) ranging from 0.68 to 0.87. Predictions were relatively poor for: (i) the Ernies catchment (lowest rainfall, forested), and (ii) months with very high flows. Overall, the predicted mean annual streamflow was within ±8% of the observed values. Keywords: monthly streamflow, land use change, conceptual model, data-based approach, groundwater


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