scholarly journals Effects of water and soil conservation works on runoff and sediment variation in the areas with high and coarse sediment yield of the middle Yellow River

2018 ◽  
Vol 38 ◽  
pp. 01033
Author(s):  
Wei Ying Sun ◽  
Pan Zhang ◽  
Li Li ◽  
Jiang Nan Chen
Keyword(s):  
Sediment Yield ◽  
Water Conservation ◽  
Human Activities ◽  
Soil Conservation ◽  
Yellow River ◽  
Soil And Water Conservation ◽  
Contribution Rate ◽  
Rainfall Variation ◽  
Runoff Reduction ◽  
Soil And Water

The areas with high and coarse sediment yield of the middle Yellow River is well known for its severe erosion, high sediment yields. Since 1982 when the 8 key soil and water conservation harnessing regions has been built, the ecological environment has been gradually improved and the amount of sediment and runoff entering the Yellow River has been reduced continuously. Some researchers considered that it was owing to the water and soil conservation works (WSCW), while others believed that it was caused by the rainfall variation, but this has not been quantified for the effect respectively. This paper deals with the effects of WSCW on runoff and sediment variation. The study has been carried out in the Sanchuanhe River watershed, where was listed as one of the 8 key soil and water conservation harnessing regions. The results show that the contribution rate of human activities was 80.2% after 1st harnessing stage (1970-1979), 43.0% after 2nd harnessing stage (1980-1989), in 3rd harnessing stage (1990-1996) it reached 98.4%, and was 44.8% after 4th harnessing stage (1997-2006). With regard to the influence on runoff reduction in the watershed, the contribution rate of human activities was 62.5% compared with the natural factors after 1st harnessing stage (1970-1979), 28.4% after 2nd harnessing stage (1980-1989), in 3rd harnessing stage (1990-1996) it reached 69.6%, and was 37.0% after 4th harnessing stage (1997-2006). The results revealed that human activities exerted the largest effects on the sediment reduction and explained 66.6% of the variation in the specific sediment yield. This study suggests that a combination of human activities and rainfall variation effectively reduces runoff and sediment delivery of the Loess Plateau. Generally The runoff reduction and contribution of rainfall variation to runoff reduction in this area were as large as human activities. After many years' harnessing the great benefit have been obtained in water and soil loss control in this watershed.

scholarly journals Causes of Variations in Sediment Yield in the Jinghe River Basin, China

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Jinliang Zhang ◽  
Yizi Shang ◽  
Jinyong Liu ◽  
Jian Fu ◽  
Shitao Wei ◽  
...  
Keyword(s):  
River Basin ◽  
Sediment Yield ◽  
Water Conservation ◽  
Yellow River ◽  
Soil And Water Conservation ◽  
Water Diversion ◽  
Sediment Discharge ◽  
Jinghe River Basin ◽  
Jinghe River ◽  
Soil And Water

Abstract The Jinghe River remains the major sediment source of the Yellow River in China; however, sediment discharge in the Jinghe River has reduced significantly since the 1950s. The objective of this study is to identify the causes of sediment yield variations in the Jinghe River Basin based on soil and water conservation methods and rainfall analyses. The results revealed that soil and water conservation projects were responsible for half of the total sediment reduction; sediment retention due to reservoirs and water diversion projects was responsible for 1.3% of the total reduction. Moreover, the Jinghe River Basin has negligible opportunity to improve its vegetation cover (currently 55% of the basin is covered with lawns and trees), and silt-arrester dams play a smaller role in reducing sediment significantly before they are entirely full. Therefore, new large-scale sediment trapping projects must be implemented across the Jinghe River Basin, where heavy rainfall events are likely to substantially increase in the future, leading to higher sediment discharge.

scholarly journals Response of LUCC on Runoff Generation Process in Middle Yellow River Basin: The Gushanchuan Basin

Water ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1237 ◽  
Author(s):  
Caihong Hu ◽  
Li Zhang ◽  
Qiang Wu ◽  
Shan-e-hyder Soomro ◽  
Shengqi Jian
Keyword(s):  
Climate Change ◽  
Human Activities ◽  
Yellow River ◽  
Trend Test ◽  
Generation Process ◽  
Runoff Generation ◽  
Contribution Rate ◽  
Runoff Reduction ◽  
Runoff Change ◽  
Significant Downward Trend

Runoff reduction in most river basins in China has become a hotpot in recent years. The Gushanchuan river, a primary tributary of the middle Yellow river, Northern China, showed a significant downward trend in the last century. Little is known regarding the relative contributions of changing environment to the observed hydrological trends and response on the runoff generation process in its watershed. On the basis of observed hydrological and meteorological data from 1965–2010, the Mann-Kendall trend test and climate elasticity method were used to distinguish the effects of climate change and human activities on runoff in the Gushanchuan basin. The results indicate that the runoff in the Gushanchuan Basin has experienced significant declines as large as 77% from 1965 to 2010, and a mutation point occurred around 1997; the contribution rate of climate change to runoff change is 12.9–15.1%, and the contribution rate of human activities to runoff change is 84.9–87.1%. Then we divided long-term data sequence into two stages around the mutation point, and analyzed runoff generation mechanisms based on land use and cover changes (LUCC). We found that the floods in the Gushanchuan Basin were still dominated by Excess-infiltration runoff, but the proportion in 1965–1997 and 1998–2010 decreased gradually (68.46% and 45.83% in turn). The proportion of Excess-storage runoff and Mixed runoff has increased, which means that the runoff is made up of more runoff components. The variation law of the LUCC indicates that the forest area increased by 49.61%, the confluence time increased by 50.42%, and the water storage capacity of the watershed increased by 30.35%.

Evaluation of Four Kinds of Water and Soil Conservation Measures on Highway Side Slope

2013 ◽  
Vol 726-731 ◽  
pp. 3843-3846
Author(s):  
Shu Li Wang ◽  
Jian Ping Zhou ◽  
Zhen Yang
Keyword(s):  
Water Conservation ◽  
Soil Conservation ◽  
Soil And Water Conservation ◽  
Water Holding Capacity ◽  
Side Slope ◽  
Network Measure ◽  
Conservation Measures ◽  
Hollow Brick ◽  
Water Holding ◽  
Soil And Water

Four kinds of protective measures and three contrast measures were chosen on Harbin-Suifenhe highway to analyze the effects of different types of soil and water conservation measure on highway side slope soil. The results showed that Soil and water conservation measures of highway side slope increased water holding capacity and soil conservation capacity significantly. The saturated water holding capacity, capillary water holding capacity and field water holding capacity of E, PP grid measure were 1.79 times,1.60 times and 1.62 times respectively of that in contrast 1 measure. E, PP grid measure, resin network measure and spread planting measures reduced runoff 58.5%, 59.3% and 50.8% compared with contrast measures. Consider of landscape and cost factors, spread planting measures was recommended to use on the smaller slope degree of highway side, E, PP grid measure, resin network measure were recommended to be used on the steep slope of highway side, hex hollow brick measure was not recommended.

scholarly journals Advances in soil conservation research: challenges for the future

2014 ◽  
Vol 4 ◽  
Author(s):  
Ildefons Pla
Keyword(s):  
Environmental Protection ◽  
Water Conservation ◽  
Soil Conservation ◽  
Soil Degradation ◽  
Crop Production ◽  
C Sequestration ◽  
Soil And Water Conservation ◽  
Water Degradation ◽  
Empirical Approaches ◽  
Soil And Water

Increased human influences on soils frequently result in widespread land and soil degradation. The processes of soil and water degradation are closely linked, as unfavourable changes in the hydrological processes affect soil water regimes. In the last 15-20 years there has been increased interest in human-induced climate change, associated with increased atmospheric concentrations of greenhouse gases. Most of the present and future problems of land and soil degradation, water supply and natural disasters are mainly attributed to these climate changes. At the same time, and probably related to it, there has been a change in the focus of research on soil and water conservation. From the late 1960s there was an increasing interest in stimulating studies related to soil and water conservation. This was a great change from the previous emphasis on more static studies of the characteristics of the soil resource, mainly for soil classification and mapping, and for land evaluation related to agricultural and other uses. This situation was due to the increasing evidence of the global problems of land, soil and water degradation, and their effects on food production and the environment. Particular attention was paid to the processes of soil and water degradation in relation to their use and management for agricultural purposes. These efforts led to the development of models and evaluation systems mainly using empirical approaches. Later studies demonstrated the limitations of the generalized universal use of these empirical approaches. Concurrently there was an increase in related organizations, conventions, congresses and conferences associated with the renewed interest on soil and water conservation. A global assessment of human-induced soil degradation (GLASOD) demonstrated the paucity, difficult accessibility and poor quality of basic information. This information, however, is essential for adequate planning and effective application of practices to prevent soil and water degradation. The most recent conventions and programs at international and regional levels are generally based on re-interpretations, and a different processing method or representation of old information using “new” terminology. In other cases, new information has been mostly generated through indirect or remote sensing deductions, usually without adequate ground-truthing. The decreasing public or private support for more integrated interdisciplinary studies and the compulsion to quickly publish papers has resulted in a very specialized and isolated consideration of different aspects related to the degradation of soil functions. This frequently results in over-simplifications, failures and even contradictions in the proposed strategies to control soil degradation. Currently we have reached quasi-stagnation in soil conservation research and a new series of soil conservation terms (soil quality, desertification, tillage erosion) and clichés (“C sequestration”, “no-tillage”) have been introduced. These are derived from different interests, but generally they are very empirical approaches without a strong scientific basis. However, they attract increased attention from organizations setting policies and providing funds for research in soil and water conservation, and as a consequence many research activities in the last 20 years have been concentrated in such topics. Regretfully, these approaches have very limited accuracy and are insufficient for developing adequate policies for land use and management. Climate, soil and socio-economic conditions differ greatly from one location to another and are changing continuously. There cannot therefore be simple universal prescriptions regarding practices of sustainable soil management for crop production and environmental protection or for mitigation of the greenhouse effect by “C sequestration” in soils. The adequate selection of those sustainable practices must be based on research with a broader vision of soil conservation, where all the system components and their interactions are considered and understood with a far-sighted approach, to ensure that short term gains in one aspect or location do not induce long-term losses in other aspects or elsewhere. Research needs to be directed to better the understanding of the processes and reactions in soils related to chemical recycling and water balance over a range of spatial and temporal scales, with the common objective of improving crop production and environmental protection. Lasting solutions will only be found if adequately trained researchers in soil science and hydrology, who recognize the complexity of the problems, develop appropriate strategies.

scholarly journals Changes in streamflow regimes and their response to different soil and water conservation measures in Loess Plateau watersheds

2021 ◽  
Author(s):  
Shuyu Zhang ◽  
Guangju Zhao ◽  
Xingmin Mu ◽  
Peng Tian
Keyword(s):  
Loess Plateau ◽  
Water Conservation ◽  
Human Activities ◽  
Soil And Water Conservation ◽  
Low Flow ◽  
Hydrological Change ◽  
River Watershed ◽  
Daily Streamflow ◽  
Conservation Measures ◽  
Soil And Water

Investigating the changes in streamflow regimes is useful for understanding the mechanisms associated with hydrological processes in different watersheds and for providing information to facilitate water resources management. In this study, we selected three watersheds, i.e., Sandu River, Hulu River, and Dali River on the Loess Plateau, to examine the changes in the streamflow regimes and to determine their responses to different soil and water conservation measures (terracing, afforestation, and damming). The daily runoff was collected continuously by three hydrological gauges close to the outlets of the three watersheds from 1965 to 2016. The eco-surplus, eco-deficit, and degree of hydrological change were assessed to detect hydrological alterations. The Budyko water balance equation was applied to estimate the potential impacts of climate change and human activities on the hydrological regime changes. Significant decreasing trends (P < 0.05) were detected in the annual streamflow in the Sandu and Dali River watersheds, but not in the Hulu River watershed where afforestation dominated. The annual eco-surplus levels were low and they decreased slightly at three stations, whereas the eco-deficit exhibited dramatic increasing trends in the Sandu and Dali River watersheds. In the Sandu River watershed (dominated by terraces), the runoff exhibited the most significant reduction and the eco-deficit was the highest among the three watersheds. The integral degrees of hydrological change were higher in the Sandu River watershed than the other two watersheds, thereby suggesting substantial variations in the magnitude, duration, frequency, timing, and rate of change in the daily streamflow. In the Dali River watershed (dominated by damming), the changes in the extreme flow were characterized by a decreasing number appearing in high flow. In these watersheds, human activities accounted for 74.1% and 91.78% of the runoff reductions, respectively. In the Hulu River watershed (dominated by afforestation), the annual runoff exhibited an insignificant decreasing trend but with a significant increase in the low flow duration. Rainfall changes accounted for 64.30% of the runoff reduction.

scholarly journals Review: Design norms for soil and water conservation structures in the sugar industry of South Africa

Water SA ◽  
2019 ◽  
Vol 45 (1 January) ◽  
Author(s):  
Daniel Otim ◽  
Jeff Smithers ◽  
Aidan Senzanje ◽  
Rianto Van Antwerpen
Keyword(s):  
South Africa ◽  
South African ◽  
Water Conservation ◽  
Soil Conservation ◽  
Soil Loss ◽  
Sugar Industry ◽  
Empirical Models ◽  
Soil And Water Conservation ◽  
The South ◽  
Soil And Water

This paper contains a critical review of the norms employed in the design of soil and water conservation structures in the South African sugar industry and highlights research needs in order to update them. Sugarcane in South Africa is grown on wide-ranging soils, sometimes in non-ideal climates and on steep topographies where soils are vulnerable to erosion. A consequence of unsustainable soil loss is reduction in field production capacity. Sugarcane fields are protected against erosion through, inter alia, the use of engineered waterways, contour banks and spill-over roads. The South African Sugarcane Research Institute (SASRI), previously known as the South African Sugar Experiment Station (SASEX), developed a nomograph to easily compute the maximum width of field panels based on soil type, tillage method, replant method, surface structures to control runoff, surface cover and slope. This was followed by guidelines and norms for the design of soil and water conservation structures. However, the nomograph was developed based on an acceptable soil loss of 20 t·ha−1·yr−1, yet soil formation rates in South Africa range between 0.25 and 0.38 t·ha−1·yr−1. Comparisons between design norms in the National Soil Conservation Manual and norms used in the sugar industry clearly show discrepancies that need to be investigated. The design of soil conservation structures includes the design of both contour bank spacing and hydraulic capacity. The sustainable soil loss method is recommended in the design of contour spacing and it determines contour spacing based on evaluation of site-specific sheet and rill erosion potential of the planned contour spacing while the hydraulic design employs Manning’s equation. Considering that increases in both design rainfall and design floods are anticipated in South Africa, it is necessary to incorporate these projections in the design of soil and water conservation structures. Many soil loss models exist, of which empirical models are the most robust and provide stable performances. The majority of empirical models are lumped models which estimate average annual soil loss. The Modified Universal Soil Loss Equation (MUSLE) estimates event-based erosion and, given that the majority of soil erosion occurs during a few extreme events annually, the design norms should be updated using the MUSLE.

Analysis and Research on the Evaluation of Economy Benefits of Small Watershed Warping Dams System

2011 ◽  
Vol 403-408 ◽  
pp. 3026-3029
Author(s):  
Yong Jia Song ◽  
Xi Min Gao ◽  
Guang Jie Wang ◽  
Jie Wang
Keyword(s):  
Water Conservation ◽  
Economic Benefit ◽  
Yellow River ◽  
Social Benefit ◽  
Soil And Water Conservation ◽  
Small Watershed ◽  
Ecological Benefit ◽  
Planning Scheme ◽  
Specification Requirement ◽  
Soil And Water

The evaluation of economy benefits of small watershed warping dams system program mainly includes foundation benefit, economic benefit, ecological benefit, social benefit on project construction. The thesis takes this small watershed planning scheme 30- year computation time as object of study ,on its soil conservation benefit, storage benefit, planting benefits and rationalities irrigation benefit, block mud benefit, economic indexes such as flood protection benefits were analyzed and calculated ,for dam system planning scheme of the economic rationality assessment provides evaluation basis. Using natural "catch-basin" concept, the people of loess plateau created warping dam whose role is storing muddy and releasing clearing, intercept sediment and silting farmland, which is a kind of soil and water conservation engineering measures. Since liberation, in the middle Yellow River area has built more than 110,000 warping dams, exceeding 0.3million hm2 place has been silting into dam land and accumulated retard mud 2.1 million tons. Since 1990s, in order to give full play to the operation safety and overall benefit of warping dams, which has formed the construction concept of dam is "in tributaries as skeletons, small watershed as a unit, matching key dam, small and middle warping dams to construction the dam system of gullies"[1]. Further assure the operation safety and the overall benefit of warping dams, which has been brought into full play. A watershed which is in order to limitation of control the flood and sediment to realize the long-term goals of soil and water conservation. Through the field survey and measurement, selected the dam system layout scheme , determinded the engineering construction scheme of the dam system of the river basin, dam system altogether layout 5 key dam (including 3 seats new dams , 2 seats old dam which is need reinforcement ) ,15 seats small and middle warping dams ,and the project under construction will last for 3 years. Basis to the specification requirement, we need evaluation analysis the planning scheme for engineering benefit. Dam system’s engineering benefits include foundation benefit, economic benefit, ecological benefit and social benefit. Basis to the specification requirement, engineering planning after the project implementation produced by the foundation and economic benefit emphatically analyzes, ecological and social benefits are briefly analyzed[2].

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