scholarly journals Simulation of Rainfall-Runoff Process in a Catchment with a Check-Dam System Equipped with a Perforated Riser Principal Spillway on the Loess Plateau of China

Water ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2450
Author(s):  
Zeyu Zhang ◽  
Junrui Chai ◽  
Shuilong Yuan ◽  
Zhanbin Li ◽  
Zengguang Xu

Check dams are applied worldwide as an effective approach for soil and water conservation. To improve the simulation accuracy of the hydrological processes in a catchment with a check-dam system, this study analyzed the applicability and accuracy of a formula for the drainage process of a perforated riser principal spillway based on observational experiments. The rainfall-runoff processes in a catchment with a check-dam system were also simulated with the recommended formulas for the drainage process of a perforated riser principal spillway. The deviations in the calculated discharge from the observed values of the experiment with the recommended formulas under normal and abnormal working conditions were within ±15% and ±5%, respectively. The hydrologic model used in this study needed only a few parameters to achieve a satisfactory simulation accuracy. The recommended formulas for the drainage process of a perforated riser principal spillway can improve the simulation accuracy of a flood peak by 7.42% and 19.58% compared with the accuracies of the technical code formula scenario and no drainage scenario, respectively. The results of this study are expected to provide a reference for flood warnings and safe operations of check-dam systems.

2021 ◽  
Author(s):  
Baiqun Wang ◽  
Weiqin Dang ◽  
Tianmin Dang

<p>The soils are susceptible to water erosion in the hilly and ravine region of the Loess Plateau due to the readily erodible attribute of soils, erosive geomorphology, land use and land cover, and erosive rainfall. The soil and water losses induced by water erosion have the significant on-site impacts on crop growths and yields in this region because of soil nutrient depletion and adverse soil moisture condition. In addition, the crops grown in different land types frequently suffer from the seasonal draught due to climate change, which leads to the decline or failure of crop yield. Therefore, the crop yields and grain production are susceptibly stressed by soil erosion and drought in this region. Soil erosion and draught are the essential issues faced by agriculture production and eco-environment. Alternatively, effective measures of soil and water conservation can incredibly control soil and water losses induced by water erosion, alleviate the influences of draught on crop yields, and sustain grain production in this region. The check dam is one of the widely adopted engineering measures of soil and water conservation in the valleys of the hilly and ravine region on the Loess Plateau. Check dam can play multiple roles in mitigating soil erosion, trapping eroded sediments, regulating runoff and creating the lands in the valleys in the context of water erosion. The check dam can control the soil erosion to some extent because it can raise the basis level of erosion in the valley. The lost sediment and runoff can be trapped by the check dam in a watershed, which can reduce resultant loss rate of soil and water in the outlet of the watershed and mitigate sediment loads in the rive connecting to the watershed. Moreover, the check dam can make sediments or eroded soils deposit so as to develop the relatively flat lands called as the dam-trapped farmland in the valleys. The dam-trapped farmlands along with the terrace lands are regarded as the crucial farmlands due to their excellent farming conditions in this region. Some grain crops, such corn, sorghum, millet or potato, are always grown in the dam-trapped farmlands, among which corn is frequently planted in this kind of farmland. The crop yields of the dam-trapped farmlands have been increasing over the last 60 years. It is evidenced that the yield of corn increased from 2250-3000 kg/ha in 1960s to 12000-15000 kg/ha at present. The corn yield of the dam-trapped farmland is 1.5-2.0 folds of that of the terrace land. The nutrient use efficiency and water use efficiency of corn in the dam-trapped farmland are much higher than those of terrace land. It can be seen that check dam have the powerful function mitigating the losses runoff and sediment, and dam-trapped land can play the critical parts in sustaining grain production and insuring food security in the hilly and ravine region of the Loess Plateau. </p><p><strong>Keywords:</strong> soil erosion; check dam; dam-trapped farmland; grain production; food security; hilly and ravine region; Loess Plateau</p>


Water ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 1054 ◽  
Author(s):  
Qiaoling Guo ◽  
Yaoyao Han ◽  
Yunsong Yang ◽  
Guobin Fu ◽  
Jianlin Li

The streamflow has declined significantly in the coal mining concentrated watershed of the Loess Plateau, China, since the 1970s. Quantifying the impact of climate change, coal mining and soil and water conservation (SWC), which are mainly human activities, on streamflow is essential not only for understanding the mechanism of hydrological response, but also for water resource management in the catchment. In this study, the trend of annual streamflow series by Mann-Kendall test has been analyzed, and years showing abrupt changes have been detected using the cumulative anomaly curves and Pettitt test. The contribution of climate change, coal mining and SWC on streamflow has been separated with the monthly water-balance model (MWBM) and field investigation. The results showed: (1) The streamflow had an statistically significant downward trend during 1955–2013; (2) The two break points were in 1979 and 1996; (3) Relative to the baseline period, i.e., 1955–1978, the mean annual streamflow reduction in 1979–1996 was mainly affected by climate change, which was responsible for a decreased annual streamflow of 12.70 mm, for 70.95%, while coal mining and SWC resulted in a runoff reduction of 2.15 mm, 12.01% and 3.05mm, 17.04%, respectively; (4) In a recent period, i.e., 1997–2013, the impact of coal mining on streamflow reduction was dominant, reaching 29.88 mm, 54.24%. At the same time, the declining mean annual streamflow induced through climate change and SWC were 13.01 mm, 23.62% and 12.20 mm, 22.14%, respectively.


2014 ◽  
Vol 71 (5) ◽  
pp. 691-699 ◽  
Author(s):  
G. Q. Wang ◽  
J. Y. Zhang ◽  
T. C. Pagano ◽  
Y. L. Liu ◽  
C. S. Liu ◽  
...  

Runoff in major rivers in China has been decreasing in recent decades, mainly due to climate change and human activity. River basin managers have a critical interest in detecting and diagnosing non-stationaries in runoff time series. Here we use a rainfall runoff model-based approach to identify the human-disturbed periods of the record. The method is applied to the Kuye River catchment, located in the Loess Plateau, China. The SimHyd model performs well for simulation of monthly natural discharges, and the method suggests that discernable human influence began in 1980. Anthropogenic effects were detectable several years earlier at the downstream stations than the upstream stations, consistent with pace and timing of soil and water conservation measures implemented across the Kuye River catchment.


2020 ◽  
Author(s):  
Zhe Gao

<p>The Geo-Hazards Triggered of Serial Reclamation Land of Extreme Precipitation in Typical Regions of the Loess Plateau<br>Gao Zhe<sup>1</sup>,Zhang Genguang <sup>1*</sup>,Gao Jian'en<sup>1,2,3</sup>,Li Xingyao<sup>1</sup>,Han Jianqiao<sup>2,3</sup>,Kang Youcai<sup>3</sup>,Guo Zihao<sup>3</sup>,Long Shaobo<sup>2</sup>,Dou Shaohui<sup>2</sup>,Zhang Yuanyuan<sup>3</sup><br>1. College of Water Resources and Architectural Engineering, Northwest A&F University, 712100, Yangling, Shaanxi, China;<br>2. Institute of Soil and Water Conservation, Northwest A&F University, 712100, Yangling, Shaanxi, China;<br>3. Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, 712100, Yangling, Shaanxi, China;</p><p>The “Gully Land Consolidation Project”(GLCP) was widely carried out all over the world, such as Spain, the United States and China. It was a new attempt to solve the shortage of regional land resources. Aiming at the problem that the influence of extreme rainstorms on the “Gully Land Consolidation Project”(GLCP) on the Loess Plateau.By using the method of actual measurement and analysis of categorical data, the erosion disaster in July 26 2017 was investigated in Niu Xue Gully of Wuding River Watershed in Zizhou County of the Central part of the Loess Plateau. The results showed : </p><p>(1) The Niu Xue Gully Small Watershed in Zizhou County (109°55'25"E, 37°39'46"N), which was located in the central part of the Loess Plateau and belonged to the northern Shaanxi Loess Hilly-Gully region. The Niu Xuegou catchment covered an area of 0.48 km<sup>2</sup> and the average altitude of the region in about 1000-1200 meters, land consolidation in the basin about 38 mu(25333.3m<sup>2</sup>)since 2014.</p><p>(2) This storm was characterized by "long duration and large precipitation", the accumulated rainfall was 147.9 mm, the average rainfall intensity was 13.45 mm/h, the maximum rainfall intensity was close to 5 mm/min, the maximum flood peak discharge was 44.64 m<sup>3</sup>/s, the flood duration was about 11 hours, and the flood recurrence period was more than once in a hundred years.</p><p>(3) The storm caused nearly a thousand geological hazards at the channel of the basin. The main types of disasters were as follows, gravity erosion types, such as landslides, landslides, and mudflows, account for 14.85% of the conventional geological hazards; secondary disasters of water erosion types, such as trench erosion and dam erosion, occurring at different locations on the slope, accounted for 51.05% and composite new-derived land destruction and dam break disasters account for nearly 10% .</p><p>(4) The damage of cascade land preparation was closely related to the average flood discharge, embankment height and ecological vegetation cover in the watershed.<br>The investigation provided technical support for the consolidation of the Chinese implementation of the "Cropland to Forest (Grass)" results on the Loess Plateau, and also provided theoretical support for the safe implementation of the “Gully Land Consolidation Project”(GLCP) around the world.<br><br></p><p>Keywords: The loess plateau; Extreme rainstorm;The “Gully Land Consolidation Project”(GLCP)</p><p>Funding:(National Key R&D Program of China: 2017YFC0504703);(National Natural Science Foundation of China,41877078,41371276,51879227);(Research and Development and Integrated demonstration of key Technologies in soil and Water Conservation Engineering,A315021615)</p><p><strong>        </strong></p>


2007 ◽  
Vol 31 (4) ◽  
pp. 389-403 ◽  
Author(s):  
Liding Chen ◽  
Wei Wei ◽  
Bojie Fu ◽  
Yihe Lü

The Loess Plateau, China, has long been suffering from serious soil erosion. About 2000 years ago, larger areas were used for grain production and soil erosion was thus becoming severe with increase in human activity. Severe soil and water loss led to widespread land degradation. During the past decades, great efforts were made in vegetation restoration to reduce soil erosion. However, the efficiency of vegetation restoration was not as satisfactory as expected due to water shortage. China initiated another state-funded scheme, the `Grain-for-Green' project in 1999, on the Loess Plateau to reduce soil erosion and improve land quality. However, the control of soil erosion effectively by land-use modification raised problems. In this paper, the lessons and experiences regarding soil and water conservation in the Loess Plateau in the past decades are analysed first. Urgent problems are then elaborated, such as the contradiction between land resource and human population, shortage of water both in amount and tempospatial distribution for vegetation growth, weak awareness of the problems of soil conservation by local officials, and poor public participation in soil and water conservation. Finally, suggestions regarding soil and water conservation in the Loess Plateau are given. In order to control soil erosion and improve vegetation, a scientific and detailed land-use plan for the Loess Plateau has to be made, in the first instance, and then planning for wise use of water resources should be undertaken to control mass movement effectively and to improve land productivity. Methods of improving public awareness of environmental conservation and public involvement in vegetation rehabilitation are also important.


Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 834 ◽  
Author(s):  
Shuilong Yuan ◽  
Zhanbin Li ◽  
Peng Li ◽  
Guoce Xu ◽  
Haidong Gao ◽  
...  

As an important soil and water conservation engineering measure, check dams have been constructed on a large scale in the Loess Plateau of China. However, their effects on runoff and sediment processes in the basin are still unclear. In this study, the hydrodynamic processes of the Wangmaogou watershed located in the Loess Plateau were simulated, and the influence of check dams on the flood and erosion dynamic processes in this watershed were also evaluated. The results showed that the check dams obviously reduced the flood peak and flood volume and mitigated the flood process. After the dam system was completed, the flood peak and flood volume were reduced by 65.34% and 58.67%, respectively. The erosion dynamic distribution of the main channel in the small watershed was changed to different extents by the different dam type combinations, and the erosion dynamic parameters of the channel decreased most after the dam system was completed, when the velocity and runoff shear stress of the outlet section were reduced by 10.69% and 31.08%, respectively. Additionally, the benefits of sediment reduction were most obvious after the check dam system was completed, with the sediment discharge in the watershed being reduced by 83.92%. The results of this study would provide specific implications for construction and management of check dams in the Loess plateau.


2021 ◽  
Author(s):  
Shuilong Yuan ◽  
Chen Li ◽  
Zhanbin Li ◽  
Zeyu Zhang

<p>As important soil and water conservation engineering measures, there are more than 100,000 check dams constructed on the Loess Plateau; these dams play a vital role in reducing floods and sediment in watersheds. However, the effects of check dams on hydrologic process are still unclear, particularly when they are deployed as a system for watershed soil and water management. This study examined the watershed hydrologic process modulated by the check dam system in a typical Loess Plateau catchment. By simulating scenarios with various numbers of check dams using a distributed physical-based hydrological model, the effects of the number of check dams on runoff generation and concentration were analyzed for the study catchment. The results showed that the presence of check dams reduced the peak discharge and the flood volume and extended the flood duration; the reduction effect on peak discharge was most significant among the three factors. The system of check dams substantially decreased the runoff coefficient, and the runoff coefficient reduction rate was greater for rainstorms with shorter return periods than for rainstorms with longer return periods. The check dams increased the capacity of the catchment regulating and storing floods and extended the average runoff concentration time in the catchment that flattened the instantaneous unit hydrograph. This study reveals the influencing mechanism of check dams on the hydrological process of a watershed under heavy rainstorm conditions and provides a theoretical basis for evaluating the effects of numerous check dams on regional hydrology and water resources on the Loess Plateau.</p>


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