scholarly journals Using WaTEM/SEDEM and HEC-HMS models for the simulation of episodic hydrological and erosion events in a small agricultural catchment

2019 ◽  
Vol 15 (No. 1) ◽  
pp. 18-29 ◽  
Author(s):  
Jana Konečná ◽  
Petr Karásek ◽  
Hana Beitlerová ◽  
Petr Fučík ◽  
Jiri Kapička ◽  
...  
Keyword(s):  
Agricultural Land ◽  
Arable Land ◽  
Extreme Rainfall ◽  
Curve Number ◽  
Careful Analysis ◽  
Rainfall Runoff ◽  
Extreme Rainfall Events ◽  
Erosion Model ◽  
Fundamental Factor

A careful analysis of rainfall-runoff events and patterns of sediment and pollution load to water bodies is crucial for the proper management of agricultural land. This study simultaneously employed the WaTEM/SEDEM long-term erosion model and the HEC-HMS episodic hydrological and erosion model to describe the runoff and sediment load evoked by extreme rainfall events in a small agricultural catchment in Czechia, using the long-term monitoring discharge and water quality episodic data. WaTEM/SEDEM helped to delineate the runoff and sediment critical source areas, subsequently incorporated into HEC-HMS. The acquired results showed that the spatial distribution of land use is a fundamental factor in the protection of watercourses from diffuse pollution sources and the transport and delivery of sediment profoundly depends on the status of crop cover on arable land near a watercourse. Integrating both models, it was shown that the tabulated Curve Number (CN) values as well as the average C-factor values had to be lowered for the majority of the modelled events to match the monitored data. A noticeable role of catchment runoff response most probably played tile drainage, which appeared to profoundly modify the episodic runoff pattern. This study showed a promising approach for the simulation of different rainfall-runoff responses of small agricultural catchments and could be applied for the delineation of areas where soil conservation measures or protective management is of high priority. The results further revealed the obvious need to revise the CN values for tile-drained catchments.

scholarly journals Trends in the Frequency of Intense Precipitation Events in Southern and Southeastern Brazil during 1960–2004

2011 ◽  
Vol 24 (7) ◽  
pp. 1913-1921 ◽  
Author(s):  
Mateus da Silva Teixeira ◽  
Prakki Satyamurty
Keyword(s):  
Extreme Rainfall ◽  
Southeastern Brazil ◽  
Extreme Rainfall Event ◽  
Southern Brazil ◽  
Extreme Rainfall Events ◽  
Rainfall Events ◽  
Annual Frequency ◽  
Long Term Trends ◽  
Increasing Trends

Abstract A new approach to define heavy and extreme rainfall events based on cluster analysis and area-average rainfall series is presented. The annual frequency of the heavy and extreme rainfall events is obtained for the southeastern and southern Brazil regions. In the 1960–2004 period, 510 (98) and 466 (77) heavy (extreme) rainfall events are identified in the two regions. Monthly distributions of the events closely follow the monthly climatological rainfall in the two regions. In both regions, annual heavy and extreme rainfall event frequencies present increasing trends in the 45-yr period. However, only in southern Brazil is the trend statistically significant. Although longer time series are necessary to ensure the existence of long-term trends, the positive trends are somewhat alarming since they indicate that climate changes, in terms of rainfall regimes, are possibly under way in Brazil.

scholarly journals On the possibilities of watershed parameterization for extreme flow estimation in ungauged basins

2015 ◽  
Vol 370 ◽  
pp. 171-175 ◽  
Author(s):  
S. Kohnová ◽  
B. Karabová ◽  
K. Hlavčová
Keyword(s):  
Extreme Rainfall ◽  
Curve Number ◽  
The United States ◽  
Water Levels ◽  
Design Flood ◽  
Extreme Rainfall Events ◽  
Local Conditions ◽  
Ungauged Sites ◽  
Design Values ◽  
Flood Estimation

Abstract. The estimation of design discharges and water levels of extreme floods is one of the most important parts of the design process for a large number of engineering projects and studies. Design flood estimates require a consideration of the hydrological, meteorological and physiographical situation, the legal requirements, and the available estimation techniques and methods. In the last decades changes in floods have been observed (Hall et al., 2014) which makes design flood estimation particularly challenging. Methods of design flood estimation can be applied either locally or regionally. A significant problem may arise in small catchments that are poorly gauged or when no recorded data exist. To obtain the design values in such cases, many countries have adopted procedures that fit the local conditions and requirements. One of these methods is the Soil Conservation Service – Curve number (SCS-CN) method which is often used in design flood estimation for ungauged sites, including those in Slovakia. Since the method was derived on the basis of the specific characteristics of selected river basins in the United States, it may lead to significant uncertainties in other countries with different hydrological conditions. The aim of this study was to test the SCN-CN method and derive regional runoff curve numbers based on rainfall and discharge measurements for selected region in Slovakia. The results show that the classical CN method gives too high estimates of event runoff depths and is not valid in the study area. To avoid the overestimation of runoff caused by extreme rainfall events, the use of the empirically derived regional runoff curves was tested and finally proposed for practical application in engineering hydrology.

scholarly journals SURFACE MELT WATER RUNOFF ON THE ARABLE LANDS OF THE LOWER DON

2021 ◽  
Author(s):  
D. P. Sidarenko ◽  
Keyword(s):  
Agricultural Land ◽  
Arable Land ◽  
Water Runoff ◽  
Erosion Processes ◽  
Rostov Region ◽  
Melt Water ◽  
Runoff Rate ◽  
The Impact ◽  
Term Data

Purpose: to study the indicators of melt water runoff from arable land of various compaction and to assess its quantitative and qualitative characteristics based on long-term data. Materials and methods. Studies of the intensity of melt water runoff were carried out in the Azov zone of Rostov region in the period 1964–2018 by a number of researchers, including the author of the article. Results. The runoff indicators for a 55-year period are characterized by significant fluctuations. Analysis of long-term data revealed that the indicator of melt water runoff rate from loose arable land for the period 1964–2018 averaged 9.0 mm/year and on compacted arable land averaged 17.5 mm/year. On loose arable land, the maximum runoff rate for a 55-year period is 25.3 mm, on compacted arable land it is 47.3 mm. As a result of the analysis of the data, it was revealed that the average water reserve in snow on the surface of the fall-plowed land is 43.7 mm, and 48.7 mm on the winter wheat sowing. In general, for two agrophonies, the runoff indicator for the period 1964–2018 was most often characterized as weak and very weak only on loose arable land. Calculations of statistical indicators of runoff data revealed that they are not uniform, for example, the coefficient of runoff variation from loose arable land was 115.4 %, and from compacted arable land 70.4 %, with a coefficient of variation above 33 %, the aggregate is considered heterogeneous. Rostov region, having a large agricultural potential, is experiencing significant problems from the impact of negative natural processes, among which one of the first places belongs to erosion processes. Conclusions. In the course of generalization of long-term data on melt water runoff from arable land of varying degrees of compaction, indicators that made it possible to plot the flow availability curves were obtained. The use of the results obtained makes it possible to predict the occurrence of runoff of various intensities and thereby prevent its negative impact on agricultural land with the minimal material costs.

scholarly journals Historical Arable Land Change in an Eco-Fragile Area: A Case Study in Zhenlai County, Northeastern China

2018 ◽  
Vol 10 (11) ◽  
pp. 3940 ◽  
Author(s):  
Yuanyuan Yang ◽  
Shuwen Zhang
Keyword(s):  
Land Cover ◽  
Agricultural Land ◽  
Arable Land ◽  
Agricultural Activity ◽  
Reconstruction Method ◽  
Land Change ◽  
Land Transformation ◽  
Mass Migration ◽  
Agricultural Areas

Long-term land changes are cumulatively a major driver of global environmental change. Historical land-cover/use change is important for assessing present landscape conditions and researching ecological environment issues, especially in eco-fragile areas. Arable land is one of the land types influenced by human agricultural activity, reflecting human effects on land-use and land-cover change. This paper selected Zhenlai County, which is part of the farming–pastoral zone of northern China, as the research region. As agricultural land transformation goes with the establishment of settlements, in this research, the historical progress of land transformation in agricultural areas was analyzed from the perspective of settlement evolution, and the historical reconstruction of arable land was established using settlement as the proxy between their inner relationships, which could be reflected by the farming radius. The results show the following. (1) There was little land transformation from nonagricultural areas into agricultural areas until the Qing government lifted the ban on cultivation and mass migration accelerated the process, which was most significant during 1907–1912; (2) The overall trend of land transformation in this region is from northeast to southwest; (3) Taking the topographic maps as references, the spatial distribution of the reconstructed arable land accounts for 47.79% of the maps. When this proxy-based reconstruction method is applied to other regions, its limitations should be noticed. It is important to explore the research of farming radius calculations based on regional characteristics. To achieve land-system sustainability, long-term historical land change trajectories and characteristics should be applied to future policy making.

scholarly journals Numerical simulation of runoff from extreme rainfall events in a mountain water catchment

2002 ◽  
Vol 2 (1/2) ◽  
pp. 109-117 ◽  
Author(s):  
J. Burguete ◽  
P. García-Navarro ◽  
R. Aliod
Keyword(s):  
Extreme Rainfall ◽  
Flood Mitigation ◽  
Mitigation Measures ◽  
Rainfall Runoff ◽  
Shallow Water Flow ◽  
Extreme Rainfall Events ◽  
Small Reservoir ◽  
Rainfall Events ◽  
Water Catchment

Abstract. A numerical model for unsteady shallow water flow over initially dry areas is applied to a case study in a small drainage area at the Spanish Ebro River basin. Several flood mitigation measures (reforestation, construction of a small reservoir and channelization) are simulated in the model in order to compare different extreme rainfall-runoff scenarios.

scholarly journals Measuring and Predicting Long-Term Land Cover Changes in the Functional Urban Area of Budapest

2020 ◽  
Vol 12 (8) ◽  
pp. 3331
Author(s):  
József Lennert ◽  
Jenő Zsolt Farkas ◽  
András Donát Kovács ◽  
András Molnár ◽  
Rita Módos ◽  
...  
Keyword(s):  
Land Cover ◽  
Urban Area ◽  
Urban Sprawl ◽  
Urban Areas ◽  
Agricultural Land ◽  
Arable Land ◽  
Land Cover Changes ◽  
Research Findings ◽  
Nature And Society

The loss of farmland to urban use in peri-urban areas is a global phenomenon. Urban sprawl generates a decline in the availability of productive agricultural land around cities, causing versatile conflicts between nature and society and threatening the sustainability of urban agglomerations. This study aimed to uncover the spatial pattern of long-term (80 years) land cover changes in the functional urban area of Budapest, with special attention to the conversion of agricultural land. The paper is based on a unique methodology utilizing various data sources such as military-surveyed topographic maps from the 1950s, the CLC 90 from 1990, and the Urban Atlas from 2012. In addition, the multilayer perceptron (MLP) method was used to model land cover changes through 2040. The research findings showed that land conversion and the shrinkage of productive agricultural land around Budapest significantly intensified after the collapse of communism. The conversion of arable land to artificial surfaces increased, and by now, the traditional metropolitan food supply area around Budapest has nearly disappeared. The extent of forests and grasslands increased in the postsocialist period due to national afforestation programs and the demand of new suburbanites for recreational space. Urban sprawl and the conversion of agricultural land should be an essential issue during the upcoming E.U. Common Agricultural Policy (CAP) reforms.

scholarly journals Mitigating Toxic Planktonic Cyanobacterial Blooms in Aquatic Ecosystems Facing Increasing Anthropogenic and Climatic Pressures

Toxins ◽  
2018 ◽  
Vol 10 (2) ◽  
pp. 76 ◽  
Author(s):  
Hans Paerl
Keyword(s):  
Climatic Variability ◽  
Extreme Rainfall ◽  
Cyanobacterial Blooms ◽  
Nitrogen And Phosphorus ◽  
Extreme Rainfall Events ◽  
Rainfall Events ◽  
Water Diversions ◽  
Short And Long Term ◽  
Reservoir Construction

Toxic planktonic cyanobacterial blooms are a pressing environmental and human health problem. Blooms are expanding globally and threatening sustainability of our aquatic resources. Anthropogenic nutrient enrichment and hydrological modifications, including water diversions and reservoir construction, are major drivers of bloom expansion. Climatic change, i.e., warming, more extreme rainfall events, and droughts, act synergistically with human drivers to exacerbate the problem. Bloom mitigation steps, which are the focus of this review, must consider these dynamic interactive factors in order to be successful in the short- and long-term. Furthermore, these steps must be applicable along the freshwater to marine continuum connecting streams, lakes, rivers, estuarine, and coastal waters. There is an array of physical, chemical, and biological approaches, including flushing, mixing, dredging, application of algaecides, precipitating phosphorus, and selective grazing, that may arrest and reduce bloom intensities in the short-term. However, to ensure long term, sustainable success, targeting reductions of both nitrogen and phosphorus inputs should accompany these approaches along the continuum. Lastly, these strategies should accommodate climatic variability and change, which will likely modulate and alter nutrient-bloom thresholds.

scholarly journals Impact Assessment of the Long-Term Fallowed Land on Agricultural Soils and the Possibility of Their Return to Agriculture

Agriculture ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 148
Author(s):  
Małgorzata Kozak ◽  
Rafał Pudełko
Keyword(s):  
Agricultural Production ◽  
Agricultural Land ◽  
Agricultural Soils ◽  
Arable Land ◽  
Nutrient Content ◽  
Soil Conditions ◽  
Positive Assessment ◽  
Large Acreage ◽  
The Impact

Agricultural land abandonment is a process observed in most European countries. In Poland and other countries of Central and Eastern Europe, it was initiated with the political transformation of the 1990s. Currently, in Poland, it concerns over 2 million ha of arable land. Such a large acreage constitutes a resource of land that can be directly restored to agricultural production or perform environmental functions. A new concept for management of fallow/abandoned areas is to start producing biomass for the bioeconomy purposes. Production of perennial crops, especially on poorer soils, requires an appropriate assessment of soil conditions. Therefore, it has become crucial to answer the question: What is the real impact of the fallowing process on soil, and is it possible to return it to production at all? For this purpose, on the selected fallowed land that met the marginality criteria defined under the project, physicochemical tests of soil properties were carried out, and subsequently, the results were compared with those of the neighboring agricultural land and with the soil valuation of the fallow land, which was conducted during its past agricultural use. The work was mainly aimed at analyzing the impact of long-term fallowing on soil pH, carbon sequestration and nutrient content, e.g., phosphorus and potassium. The result of the work is a positive assessment of the possibility of restoring fallowed land for agricultural production, including the production of biomass for non-agricultural purposes. Among the studied types of fallow plots, the fields where goldenrod (Solidago L.—invasive species) appeared were indicated as the areas most affected by soil degradation.

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