Effects of a check dam system on the runoff generation and concentration processes of a catchment on the Loess Plateau

2021 ◽  
Author(s):  
Shuilong Yuan ◽  
Chen Li ◽  
Zhanbin Li ◽  
Zeyu Zhang
Keyword(s):  
Loess Plateau ◽  
Peak Discharge ◽  
Runoff Coefficient ◽  
Check Dam ◽  
Return Periods ◽  
Runoff Generation ◽  
The Loess Plateau ◽  
Hydrologic Process ◽  
Check Dams ◽  
Soil And Water

<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>

scholarly journals Physics-Based Simulation of Hydrologic Response and Sediment Transport in a Hilly-Gully Catchment with a Check Dam System on the Loess Plateau, China

Water ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1161 ◽  
Author(s):  
Honglei Tang ◽  
Qihua Ran ◽  
Jihui Gao
Keyword(s):  
Sediment Transport ◽  
Loess Plateau ◽  
Distributed Model ◽  
Check Dam ◽  
The Loess Plateau ◽  
Engineering Structures ◽  
Small Catchment ◽  
Check Dams ◽  
Water Redistribution ◽  
Physics Based Simulation

Check dams are among of the most widespread and effective engineering structures for conserving water and soil in the Loess Plateau since the 1950s, and have significantly modified the local hydrologic responses and landforms. A representative small catchment was chosen as an example to study the influences of check dams. A physics-based distributed model, the Integrated Hydrology Model (InHM), was employed to simulate the impacts of check dam systems considering four scenarios (pre-dam, single-dam, early dam-system, current dam-system). The results showed that check dams significantly alter the water redistribution in the catchment and influence the groundwater table in different periods. It was also shown that gully erosion can be alleviated indirectly due to the formation of the expanding sedimentary areas. The simulated residual deposition heights (Δh) matched reasonably well with the observed values, demonstrating that physics-based simulation can help to better understand the hydrologic impacts as well as predicting changes in sediment transport caused by check dams in the Loess Plateau.

scholarly journals Rainfall-runoff processes in the Loess Plateau, China: Temporal dynamics of event rainfall-runoff characteristics and diagnostic analysis of runoff generation patterns

2020 ◽  
Author(s):  
Qiang Wu ◽  
Zhaoxi Zhang ◽  
Guodong Zhang ◽  
Shengqi Jian ◽  
Li Zhang ◽  
...  
Keyword(s):  
Loess Plateau ◽  
Time Scale ◽  
Overland Flow ◽  
Yellow River ◽  
Separation Procedure ◽  
Runoff Coefficient ◽  
Rainfall Runoff ◽  
Runoff Generation ◽  
The Loess Plateau

Abstract. The Loess Plateau is the most erosion-prone area in China, while under large-scale ecological restoration runoff and sediments continue to decrease. This study examined the runoff generation mechanism at the catchment scale to understand the change in runoff generation. Six baseflow used to separation method were tested and the nonparametric simple smoothing method was seperating base flow. With the event runoff separation procedure, 340 rainfall–runoff events are selected in five typical catchments affected by significant human intervention in the Loess Plateau. Runoff characteristics, such as the event runoff coefficient, time scale, rise time, and peak discharge are studied on monthly and long-term scales. In catchments of Jialuhe, Chabagou and Gushanchuan with poor vegetation runoff response is strongly decided by rainfall intensity and is produced by Horton overland flow (HOF). While the mountainous catchments of Jingle and Zulihe runoff response is controlled by rainfall volume. The relation between runoff event characteristics and rainfall is complicated in Loess Plateau, where rainfall and underlying surface is significantly changing. The monthly of event characteristics is mostly controlled by rainfall characteristics. Long-term runoff coefficient experiences decreasing trend, while time scale trend is increasing. Land use changes lead to increasing catchment wetness display mostly strong reason in event characteristic response. According to our proposed framework for classifying dominant runoff generation patterns considering of hydrograph response time, discharge source, and flow paths, HOF runoff is still the dominant mechanism, but gradually shifts to Dunne overland flow (DOF) and combination runoff. We speculate that the reduction in runoff in the Yellow River is likely to be the dominant runoff mechanism changing.

Soil erosion and sediment interception by check dam in watershed under extreme rainstorm on the Loess Plateau, China

2020 ◽  
Author(s):  
leichao bai
Keyword(s):  
Soil Erosion ◽  
Loess Plateau ◽  
Sediment Deposition ◽  
Delivery Ratio ◽  
Construction Technology ◽  
Check Dam ◽  
The Loess Plateau ◽  
Check Dams ◽  
Hydrological Station ◽  
Extreme Rainstorms

<p>The magnitude of soil erosion and sediment reduction efficiency of check dams under extreme rainstorms are long-standing concerns. This paper aims to use check dams to deduce the amount of soil erosion under extreme rainstorms in watersheds and to identify the difference of sediment intercepting efficiency of different types of check dams. Based on the sediment deposition of 12 check dams with 100% sediment intercepting efficiency and sub-catchment clustering by taking 12 check dams-controlled catchments as standard separately, the amount of soil erosion caused by an extreme rainstorm event on July 26<sup>th</sup>, 2017 (named “7·26” extreme rainstorm) was deduced in the Chabagou watershed in the hill and gully region of the Loess Plateau. The differences of sediment intercepting efficiency among check dams in the watershed were analysed according to the field observation 17 check dams. The results showed that the average erosion intensity under the ‘7·26’ extreme rainstorm was approximately 2.03×10<sup>4 </sup>t·km<sup>-2</sup>, which was 5 times that in the second erosive rainfall in 2017 (4.15×10<sup>3 </sup>t·km<sup>-2</sup>) and 11-384 times that in 2018 (0.53×10<sup>2 </sup>t·km<sup>-2</sup> - 1.81×10<sup>3 </sup>t·km<sup>-2</sup>). Under the ‘7·26’ extreme rainstorm, the amount of soil erosion in the Chabagou watershed above Caoping hydrological station was 4.20×10<sup>6</sup> tons. The sediment intercepting efficiencies check dams with drainage canals (including the destroyed check dams) and with drainage culverts was 6.48% and 39.49%, respectively. The total actual sediment amount trapped by the check dam was 1.11×10<sup>6</sup> tons, accounting for 26.36% of the total soil erosion amount. In contrast, 3.09×10<sup>6</sup> tons of sediment was inputted to the downstream channel, and the sediment deposition in the channel was 2.23×10<sup>6</sup> tons, accounting for 53.15% of the total amount of soil erosion. The amount of sediment transport at the hydrological station was 8.60×10<sup>5</sup> tons. The sediment delivery ratio (SDR) under the “7·26” extreme rainstorm was 0.21. The results indicated that the amount of soil erosion was huge, and the sediment intercepting efficiency of check dams was greatly reduced under extreme rainstorms. It is necessary to strengthen the management and construction technology standards of check dams to improve the sediment intercepting efficiency and flood safety in the watershed.</p>

Check Dam-Trapped Farmlands on the Hilly and Ravine Region of the Loess Plateau: Soil Fertility, Crop Yields and Faced Challenges

2020 ◽  
Author(s):  
Weiqin Dang ◽  
Baiqun Wang ◽  
Tianmin Dang
Keyword(s):  
Soil Moisture ◽  
Soil Fertility ◽  
Loess Plateau ◽  
Crop Yields ◽  
Water Erosion ◽  
Check Dam ◽  
The Loess Plateau ◽  
Water Losses ◽  
Soil Moisture Condition ◽  
Soil And Water

<p>It is well known that soils are vulnerable to water erosion in the hilly and ravine region of the Loess Plateau. The soil and water losses induced by water erosion have both the on-site and off-site impacts in this region, which causes the on-site decline of soil fertility and reductions of crop yields on sloping farmlands, and drains the generated overland runoff and transports the eroded soils/sediments to the off-site valleys or rivers to threaten the safety of the river systems. Constructing the check dam in the valley has the long history and is regarded as one of the powerful measures to control the soil and water losses in a watershed in this region. On the one hand, the check dam plays the vital roles in trapping the large amounts of sediment generated from the sloping lands and buffering the drainage of runoff yielded form the slopes. On the other hand, the silted sediments or eroded soils by the check dam can develop the relatively flat lands in the valleys. The check dam-trapped lands can be utilized to grow the crops and become the farmlands in a watershed. The investigation indicates that the contents of soil organic matter, nutrients and soil moisture of he check dam-trapped farmlands are higher than those of the sloping farmlands or the terraces. According to the analysis on the survey data on the crop yield evolutions in the watershed in this region, the crop yields of check dam-trapped farmlands have been significantly higher than those of the sloping farmlands and terraces in the scenario of the similar fertilizer input and crop cultivars due to the optimum soil moisture condition in the check dam-trapped farmlands. However, the check dam-trapped farmlands face some challenges under the climate change. Some of the check dam-trapped farmlands or the grown crops in these kinds of lands are susceptible to the damage arose from extreme rainstorms because of the outdated measures of soil and water conservation for these kinds of farmlands. In some watersheds, the check dam-trapped farmlands are prone to salinization due to the outdated management. Therefore，the protective measures and techniques of harnessing salinization for the check dam-trapped farmlands should be updated over time in order to keep the check dam-trapped farmlands safe and maintain the higher crop yields in those farmlands in the hilly and ravine region of the Loess Plateau.</p>

The Roles of Check Dams and Dam-Trapped Farmlands in the Hilly and Ravine Region of the Loess Plateau: Soil Erosion Control, Grain Production and Food Security 

2021 ◽  
Author(s):  
Baiqun Wang ◽  
Weiqin Dang ◽  
Tianmin Dang
Keyword(s):  
Food Security ◽  
Soil Erosion ◽  
Loess Plateau ◽  
Water Conservation ◽  
Crop Yields ◽  
Water Erosion ◽  
Check Dam ◽  
Grain Production ◽  
The Loess Plateau ◽  
Soil And Water

<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>

scholarly journals Effects of wheat stubble on runoff, infiltration, and erosion of farmland on the Loess Plateau, China, subjected to simulated rainfall

Solid Earth ◽  
2017 ◽  
Vol 8 (2) ◽  
pp. 281-290 ◽  
Author(s):  
Linhua Wang ◽  
Bo Ma ◽  
Faqi Wu
Keyword(s):  
Loess Plateau ◽  
Sediment Concentration ◽  
Simulated Rainfall ◽  
The Loess Plateau ◽  
Water Losses ◽  
Runoff Volume ◽  
Runoff Reduction ◽  
Wheat Stubble ◽  
Summer Fallow ◽  
Soil And Water

Abstract. Soil and water losses in agriculture are major environmental problems worldwide, especially on the Loess Plateau, China. Summer fallow management may help to control soil erosion and conserve water. This study investigated the effects of wheat stubble on runoff, infiltration, and soil loss in laboratory plots under simulated rainfall. The treatments comprised wheat stubble cover (WS) and traditional plowing (TP) in runoff plots (4.0 m  ×  1.0 m) with three slope gradients (5, 10, and 15°) under simulated rainfall at 80 mm h−1 for 1 h. The runoff volume from WS plots was significantly less than that from TP. The runoff reduction with WS ranged from 91.92 to 92.83 % compared with TP. The runoff rates varied with the runoff volume in the same manner. The infiltration amount was higher with WS (94.8–96.2 % of rainwater infiltrated) than TP (35.4–57.1 %). The sediment concentration was significantly lower with WS than TP. Compared with TP (304.31–731.23 g m−2), the sediment losses were reduced dramatically in WS (2.41–3.78 g m−2) and the sediment loss slightly increased with slope; however, it was greatly increased as slope increased in TP. These results revealed that the stubble cover was the main factor reducing runoff and sediment losses and improving infiltration and that stubble showed a great potential to control erosion and conserve soil and water resources during the summer fallow period in the Loess Plateau region.

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