The hydrological influence of black locust plantations in the loess area of northwest China     

Wang Yanhui 《水文研究》1992,6(2):241-251

Black locust (Robina pseudoacacia) has become one of the most important shelter species in the loess area of northwest China. This paper summarizes recent research concerning its hydrological influence, including canopy interception, litter absorption capacity, its effect on rainfall kinetic energy, infiltration rates, surface runoff, soil moisture, and evapotranspiration, and its role in soil conservation. Several predictive models are listed. on the basis of existing results, optimum characteristics for an effective plantation are defined, and problems requiring further research are identified.  相似文献   

Infiltration at the Tai rain forest (Ivory Coast): Measurements and modelling     

A. Wierda  A. W. L. Veen  R. W. A. Hutjes 《水文研究》1989,3(4):371-382

Infiltration experiments have been performed at three sites along a well-known catena under virgin tropical rain forest using a portable sprinkling infiltrometer. Experimentally determined infiltration curves are presented. Infiltration curves are also simulated on the basis of the Mein-Larson equation. The parameters for this model have been obtained from the infiltration curves (saturated conductivity) and simple soil moisture determinations (fillable porosity). The agreement between experimentally determined and modelled infiltration is reasonable, provided (a) saturated conductivity as derived from the experimental data is corrected, (b) a storage parameter, also derived from the experimental data, is added to the Mein-Larson model, and (c) the decline in soil porosity with depth is either small or occurs abruptly at shallow depth. Comparison of observed infiltration rates with rainfall intensity shows that Horton Overland Flow has to occur naturally at least on the middle and lower section of the catena. Despite the fact that most parameters can be estimated in principle from basic soil data, it remains advisable to obtain sprinkling infiltrometer field measurements, because of soil variability due to dynamic surface conditions, macroporosity, air entrapment, and irregularity of the wetting front.  相似文献   

Transient deterministic shallow landslide modeling: Requirements for susceptibility and hazard assessments in a GIS framework   总被引：12，自引：0，他引：12  

J.W. Godt  R.L. Baum  W.Z. Savage  D. Salciarini  W.H. Schulz  E.L. Harp 《Engineering Geology》2008,102(3-4):214

  相似文献   

Variation of infiltration rate through karstic surfaces due to land use changes: A case study in Murgia (SE-Italy)   总被引：1，自引：0，他引：1  

Filomena Canora  M. Dolores Fidelibus  Antonella Sciortino  Giuseppe Spilotro   《Engineering Geology》2008,99(3-4):210

Groundwaters of the Murgia carbonate aquifer represent the main groundwater resource of the Apulia region (SE Italy). In the highlands (Alta Murgia) karst crops out in different forms and textures which have been preserved up to the 1970s: little evolved agriculture and sheep rearing produced only a marginal modification of the epikarst while a high degree of division into parcels by drystone walls helped in preserving soils from erosion. In the last years the original scenery of the Alta Murgia changed due to widespread transformations of surface karstic textures for agricultural purposes, with undeniable negative consequences on the hydrogeological balance, concerning both the infiltration and the runoff terms. Stone shattering led to flattening and deep alteration of a large part of the original karstic landscape and to demolition of drystone walls.In a study area of about 139 km² located in the Alta Murgia, the comparison of aerial photos related to the period 1950–2001 indicated that stone shattering had occurred for about 42% of the area.The hydrological behaviour of the first soil layer of experimental parcels representing both shattered stone and natural karstic surface textures was analysed by using the numerical model Hydrus-2D with the aim of estimating the variation on infiltration rate due to stone shattering. Intensive field and laboratory measurements concerned soil texture, soil water content, pressure head, saturated hydraulic conductivity, pan evaporation and meteorological parameters.  相似文献   

新疆伊犁南岸干渠黄土渠段湿陷性分析     

汪海涛  刘晓丽  王思敬 《工程地质学报》2008,16(2):222-228

新疆伊犁南岸干渠工程明渠段沿线风积黄土广布,黄土的湿陷性对工程具重要影响。本文依据规范并考虑工程实际,对区内黄土的湿陷性等级、起始湿陷压力、湿陷性黄土厚度进行了综合分析,分析了挖方渠道黄土的湿陷性程度;并在考虑降雨土体非饱和过程的条件下,对填方渠道土地基的湿陷变形量进行了详细深入的研究。通过分析认为,工程区黄土渠段为非自重湿陷性场地,湿陷等级为Ⅰ～Ⅱ级;压实后的黄土不具湿陷性;无论是挖方渠道还是填方渠道,经过换填处理和设置排水措施后,即可消除湿陷性,无需要再做专门处理措施。  相似文献   

Modeling of rainfall-triggered shallow landslide   总被引：5，自引：3，他引：5  

Tung-Lin Tsai  Jinn-Chuang Yang 《Environmental Geology》2006,50(4):525-534

By integrating hydrological modeling with the infinite slope stability analysis, a rainfall-triggered shallow landslide model was developed by Iverson (Water Resour Res 36:1897-1910, 2000). In Iverson’s model, the infiltration capacity is assumed to be equivalent to the saturated hydraulic conductivity for finding pressure heads analytically. However, for general infiltration process, the infiltration capacity should vary with time during the period of rain, and the infiltration rate is significantly related to the variable infiltration capacity. To avoid the unrealistically high pressure heads, Iverson employed the beta-line correction by specifying that the simulated pressure heads cannot exceed those given by the beta line. In this study, the suitability of constant infiltration capacity together with the beta-line correction for hydrological modeling and landslide modeling of hillslope subjected to a rainfall is examined. By amending the boundary condition at ground surface of hillslope in Iverson’s model, the modified Iverson’s model with considering general infiltration process is developed to conduct this examination. The results show that the unrealistically high pressure heads from Iverson’s model occur due to the overestimation of infiltration rate induced from the assumption that the infiltration capacity is identical to the saturated hydraulic conductivity. Considering with the general infiltration process, the modified Iverson’s model gives acceptable results. In addition, even though the beta-line correction is applied, the Iverson’s model still produces greater simulated pressure heads and overestimates soil failure potential as compared with the modified Iverson’s model. Therefore, for assessing rainfall-triggered shallow landslide, the use of constant infiltration capacity together with the beta-line correction needs to be replaced by the consideration of general infiltration process.  相似文献   

Infiltration on mountain slopes: a comparison of three environments     

Carol P. Harden  P. Delmas Scruggs 《Geomorphology》2003,55(1-4):5

Water is well established as a major driver of the geomorphic change that eventually reduces mountains to lower relief landscapes. Nonetheless, within the altitudinal limits of continuous vegetation in humid climates, water is also an essential factor in slope stability. In this paper, we present results from field experiments to determine infiltration rates at forested sites in the Andes Mountains (Ecuador), the southern Appalachian Mountains (USA), and the Luquillo Mountains (Puerto Rico). Using a portable rainfall simulator–infiltrometer (all three areas), and a single ring infiltrometer (Andes), we determined infiltration rates, even on steep slopes. Based on these results, we examine the spatial variability of infiltration, the relationship of rainfall runoff and infiltration to landscape position, the influence of vegetation on infiltration rates on slopes, and the implications of this research for better understanding erosional processes and landscape change.Infiltration rates ranged from 6 to 206 mm/h on lower slopes of the Andes, 16 to 117 mm/h in the southern Appalachians, and 0 to 106 mm/h in the Luquillo Mountains. These rates exceed those of most natural rain events, confirming that surface runoff is rare in montane forests with deep soil/regolith mantles. On well-drained forested slopes and ridges, apparent steady-state infiltration may be controlled by the near-surface downslope movement of infiltrated water rather than by characteristics of the full vertical soil profile. With only two exceptions, the local variability of infiltration rates at the scale of 10° m overpowered other expected spatial relationships between infiltration, vegetation type, slope position, and soil factors. One exception was the significant difference between infiltration rates on alluvial versus upland soils in the Andean study area. The other exception was the significant difference between infiltration rates in topographic coves compared to other slope positions in the tabonuco forest of one watershed in the Luquillo Mountains. Our research provides additional evidence of the ability of forests and forest soils to preserve geomorphic features from denudation by surface erosion, documents the importance of subsurface flow in mountain forests, and supports the need for caution in extrapolating infiltration rates.  相似文献   

A time-space based approach for mapping rainfall-induced shallow landslide hazard   总被引：2，自引：0，他引：2  

Mowen Xie  Tetsuro Esaki  Meifeng Cai 《Environmental Geology》2004,46(6-7):840-850

A rainfall-induced shallow landslide is a major hazard in mountainous terrain, but a time-space based approach is still an unsettled issue for mapping rainfall-induced shallow landslide hazards. Rain induces a rise of the groundwater level and an increase in pore water pressure that results in slope failures. In this study, an integrated infinite slope analysis model has been developed to evaluate the influence of infiltration on surficial stability of slopes by the limit equilibrium method. Based on this new integrated infinite slope analysis model, a time-space based approach has been implemented to map the distributed landslide hazard in a GIS (Geographic Information Systems) and to evaluate the shallow slope failure induced by a particular rainfall event that accounts for the rainfall intensity and duration. The case study results in a comprehensive time-space landslide hazard map that illustrates the change of the safety factor and the depth of the wetting front over time.  相似文献   

Variation in nitrate and calcium as indicators of recharge pathways in Nolte Spring, PA   总被引：1，自引：0，他引：1  

L. Toran  W. B. White 《Environmental Geology》2005,48(7):854-860

This study documents variations in calcium and nitrate concentrations that suggest changes in recharge pathways in a karst spring. The nitrate concentrations increased at the end of the growing season, showing the importance of the soil zone in the recharge pathway. The increase occurred over just a few days, which may be indicative of a change in contribution of baseflow in different seasons from deep to shallow groundwater. The calcium concentrations decreased several days after storm events. A change in the carbonate equilibrium is hypothesized because chloride was not diluted during these events. The decrease in calcium could be due to outgassing and calcite precipitation in the recharge area when older, higher ionic strength matrix water mixes with stormwater in open conduits. The use of geochemical indicators to better understand recharge pathways benefited from long-term monitoring and periods of daily sampling.  相似文献   

The hydrological response of soil surfaces to rainfall as affected by cover and position of rock fragments in the top layer   总被引：1，自引：0，他引：1  

J. Poesen  F. Ingelmo-Sanchez  H. Mucher 《地球表面变化过程与地形》1990,15(7):653-671

Rainfall experiments have been conducted in the laboratory in order to assess the hydrological response of top soils very susceptible to surface sealing and containing rock fragments in different positions with respect to the soil surface. For a given cover level, rock fragment position in the top soil has an ambivalent effect on water intake and runoff generation. Compared to a bare soil surface rock fragments increase water intake rates as well as time of runoff concentration and decrease runoff volume if they rest on the soil surface. For the same cover level, rock fragments reduce infiltration rate and enhance runoff generation if they are well embedded in the top layer. The effects of rock fragment position on infiltration rate and runoff generation are proportional to cover percentage. Micromorphological analysis and measurements of the saturated hydraulic conductivity of bare top soils and of the top layer underneath rock fragments resting on the soil surface reveal significant differences supporting the mechanism proposed by Poesen (1986): i.e. runoff generated as rock flow or as Horton overland flow can (partly) infiltrate into the unsealed soil surface under the rock fragments, provided that they are not completely embedded in the top layer. Hence, rock fragment position, beside other rock fragment properties, should be taken into account when assessing the hydrological response of soils susceptible to surface sealing and containing rock fragments in their surface layers. A simple model, based on the proportions of bare soil surface, soil surface occupied by embedded rock fragments, and soil surface covered with rock fragments resting on the soil surface, describes the runoff coefficient data relatively well.  相似文献