Integrated erosion control measures and environmental effects in rocky mountainous areas in northern China

Based on observations of runoff plots and field investigations of gully cross-sections, impacts of various soil and water conservation measures on runoff and sediment yield are analyzed for different rainfall conditions. The results show that antecedent rainfall and rainfall intensity are the main factors affecting the runoff and soil erosion processes. Rainfall events with antecedent rainfall can produce high runoff and sediment yield. Large differences in the characteristics of two rainfall events will result in greater variations of total runoff and sediment yield from the same runoff plot. Under the same soil control measure and rainfall condition, soil and water conservation measures can reduce the impacts of antecedent rainfall and rainfall intensity on runoff and soil erosion. Among various measures, level terrace seems to be the greatest for soil conservation purposes. Combining with engineering measures,Vegetation measures is also effective in controlling runoff and soil erosion. In the initial stage of vegetation enclosure measures, engineering measure is necessary to improve the environment for ecological recovery. Gully head protection can control gully erosion effectively, but the effectiveness of gully head protection would be reduced when rainfall intensity increases. Therefore, the design of a gully head protection structure must be based on local hydrological conditions.     

Rates and mechanisms of discontinuous gully erosion in a red-brown earth catchment,new south wales,australia

Rainfall, runoff, sediment discharge, and gully expansion were measured for five years in a small (45 ha) catchment in central N.S.W. Sixty per cent of the sediment produced from this catchment originated from gully erosion. Gully head erosion was episodic depending on pipe development, cracking, and soil detachment during small runoff events which prepared the heads for rapid soil movement by the infrequent large event.     

The catastrophe forecast of the annual sidement transport by debris flow in Jiangjia Gully,Yunnan Province,China

On the basis of the observational data on the annual sediment transport by debris flow in recent 8 years, appling the catastrophe forecast method of Grey System Theory, this study has established the catastrophe model of the annual sediment transport by debris flow in Jiangjia Gully. It has forecasted the next potential catastrophic year in which the annual sediment transport will be over the catastrophic. threshold 2 million m3. Furthermore, it has introduced the "equal dimension-new information model", which makes the forecast be done continuously.     

昭通头寨沟特大型灾害性滑坡研究

昭通头寨沟滑坡具有启程剧动、行程高速、来势凶猛、破坏严重和灾害面广的特点。该滑坡是一个剧动式高速特大型岩质滑坡。本文分析了滑坡的成因和滑动的机制,根据滑坡运动后的残留痕迹和堆积地貌特征,认为头寨沟滑坡的运动方式和路径独具特点。通过对滑后斜坡稳定性的评价,说明滑坡部分残体仍有活动迹象,据此提出了滑坡的防治措施。     

河南卢氏县罗家沟泥石流灾害及其防治

通过对罗家沟地形地貌、暴雨特征、流域面积、地层岩性、地质构造、水文地质条件、泥石流物源的调查与分析研究,针对该泥石流具有危险性高、流量大、流速缓的特点,结合受灾害对象及其分布区域与整体布局的关系,按照防治结合、因地制宜、重点突出的原则设置了以排为主、挡土墙、排导槽、防护堤加板涵的综合治理方案。     

贵州望谟县田坝沟泥石流灾害特征及防治建议

田坝沟是一条低频率泥石流沟,在2011年6月6日暴雨条件下暴发泥石流。文章着重分析其物源、地形和降雨条件,通过现场取样和断面截取,获得了流速、流量等参数,预测了田坝沟泥石流的未来活动趋势,并提出了相关的防治建议。     

四川省都江堰市虹口乡红色村干沟泥石流特征及危险性评价

红色村干沟位于都江堰市虹口乡,"5.12"地震之后多次发生泥石流。2013年"7.9"特大暴雨后引发泥石流,摧毁沟口居民房屋,淹埋农田;沟内仍存在大量松散物源,沟口的居民安置点和公路仍受泥石流的威胁。笔者结合灾害应急调查资料,采用单沟泥石流危险性评价方法,对红色村干沟泥石流的形成条件、发育特征、易发程度和危险性进行分析,结果显示该沟泥石流易发程度为中等,危险性中等,对沟口居民生命财产和公路交通存在威胁。     

基于DEM的单位汇水面积尺度转换(英文)

Specific Catchment Area (SCA) is defined as the upstream catchment area of a unit contour. As one of the key terrain parameters, it is widely used in the modeling of hydrology, soil erosion and ecological environment. However, SCA value changes significantly at different DEM resolutions, which inevitably affect terrain analysis results. SCA can be described as the ratio of Catchment Area (CA) and DEM grid length. In this paper, the scale effect of CA is firstly investigated. With Jiuyuangou Gully, a watershed about 70 km2 in northern Shaanxi Province of China, as the test area, it is found that the impacts of DEM scale on CA are different in spatial distribution. CA value in upslope location becomes bigger with the decrease of the DEM resolution. When the location is close to downstream areas the impact of DEM scale on CA is gradually weakening. The scale effect of CA can be concluded as a mathematic trend of exponential decline. Then, a downscaling model of SCA is put forward by introducing the scale factor and the location factor. The scaling model can realize the conversion of SCA value from a coarse DEM resolution to a finer one at pixel level. Experiment results show that the downscaled SCA was well revised, and consistent with SCA at the target resolution with respect to the statistical indexes, histogram and spatial distribution. With the advantages of no empirical parameters, the scaling model could be considered as a simple and objective model for SCA scaling in a rugged drainage area.     

资勒沟泥石流灾害及特征

1987年6月5日晨,资勒沟暴发了一场灾害性泥石流,沟口的公路桥和凉红道班被摧毁,致使5名道班工人死亡。该沟是一条暴发频率很低的泥石流沟。这场泥石流是由局地暴雨激发而引起的,雨强为55.2毫米/小时。泥石流为粘性,容重2.18吨/立方米,最大流量352.1立方米/秒,最大流速10—12米/秒,总冲出物方量约8万—9万立方米。     

Anthropogenic alluvial sediments in North Carolina Piedmont gullies indicate swift geomorphic response to 18th century land-use practices

ABSTRACT

Gullies are common erosional features in the Piedmont of North Carolina that have often been studied as indicators of poor land-management practices. However, the timing of gully formation, and thus the specific practices that caused their formation, has been largely overlooked in the literature. Here, we use the timing of gully formation to examine the geomorphic and anthropogenic triggers for erosion in the Piedmont. To do this, we mapped 74 gullies in the landscape and found that most contained alluvium within the gully or in alluvial fans. Soil pits were dug at a subset of the gully sites (16 in alluvium, 1 in colluvium, and 1 upland comparison) and examined for soil development, organic content, and particle size. Seven charcoal fragments were sampled from the soil pits and were radiocarbon dated. Radiocarbon ages cluster in the late 1700s, which suggests that early European settlers had an immediate impact on the landscape through deforestation and agriculture. The swift response of the landscape to deforestation and agriculture indicates that the argillic Piedmont soils are pre-disposed to erosion. Our results highlight the importance of erosion prevention as reforested farmland is cleared during urban expansion.