A computer-based datalogging system used to investigate the infiltration process under natural rainfall conditions     

C. I. Essery  D. N. Wilcock  W. McClean 《水文研究》1987,1(3):283-292

The system described in this paper uses a commercial, portable computer to monitor rainfall, surface runoff, soil moisture potential, soil temperature, and water table levels. The system is designed as a permanent field instrument which reads 16 analogue and two digital channels. It offers 10-bit accuracy and records data on both magnetic tape and paper for greater security. The computer program is in Microsoft BASIC and can therefore be readily altered to change the measurement regime. Although designed to investigate the infiltration process the system is easily adapted to monitor other environmental processes.  相似文献   

Treatment of a potential soil capping for open-cut mines (Part 1): Influence of prior management on responses to a phyto-organic amendment   总被引：1，自引：1，他引：0  

M. A. Harris  P. Rengasamy 《Environmental Geology》2004,46(1):15-21

Extraction of mineral ores, and some projects in engineering geology commonly entail removal of large tracts of valuable topsoil called overburden. A potential mine overburden capping material from an Alfisol with different management histories was treated to assess its physical responses to phyto-organic amendments during storage. Although there were small inceases in hydraulic conductivity, phyto-organic amendments did not greatly improve the physical properties of the Alfisol which had previously been cultivated for several years, as changes in stability and water retention were generally not statistically significant. However, very substantial increases of stability (about 25%) and water retention about 40%) occurred in the same soil which had previously been under a long-term permanent pasture regime. As topsoils can quickly deteriorate when removed and stored, prior soil management should be taken into account where topsoil is to be removed and replaced as a capping after operations such as ore extraction.  相似文献   

Effects of oil spill on seawater infiltration and macrobenthic community in tidal flats   总被引：1，自引：0，他引：1  

Chung IY  Cho KJ  Hiraoka K  Mukai T  Nishijima W  Takimoto K  Okada M 《Marine pollution bulletin》2004,49(11-12):959-963

Tidal flat ecosystem simulators are used to clarify the effects of stranded fuel oil on tidal flat ecosystems. Results show that oil spills increase the periphyton on sediment by decreasing the predation stress caused by deposit feeders. About a month after an oil spill, the total population density of the macrobenthos recovered. The oxidation-reduction potential in the surface sediment drops to a negative value after the oil spill, and the anaerobic condition throughout the sediment seems to be responsible for the decrease in the population density of the macrobenthos. The infiltration volume of seawater into the oil-stranded sediment decreases to a third of that without the oil spill. The recovery of infiltration volume after about a month coincides with the recovery of the population density of the macrobenthos. This result suggests that the macrobenthic population is highly dependent on the infiltration of seawater.  相似文献   

Acceleration of Horton overland flow and erosion by footpaths in an upland agricultural watershed in northern Thailand   总被引：1，自引：0，他引：1  

A. D. Ziegler  R. A. Sutherland  T. W. Giambelluca 《Geomorphology》2001,41(4)

Through field rainfall simulation experiments in an upland mountainous watershed of northern Thailand, we have identified two phenomena that increase the potential for Horton overland flow (HOF) generation on agricultural lands. First, there appears to be a transition period of 12–18 months, extending from the time of abandonment until the formation of a dense vegetation layer capable of intercepting rainfall and ponding surface water, during which HOF generation is accelerated. Simulation data indicate these recently abandoned fields may have runoff coefficients (ROCs) as high as 40% during large seasonal storms with wet antecedent soil moisture conditions. In comparison, actively cultivated lands and advanced (>16–18 months) fallow fields, the land surfaces existing before and after the threshold period, have ROCs≤4%. Secondly, compacted path surfaces initiate HOF within agricultural fields, which have saturated hydraulic conductivity (K_s) values that are 100–200 mm h⁻¹ higher. In the study area, path/furrow networks, comprising 8–24% of field surface areas, are designed to provide walking access within fields and channel excess surface flow from the fields. Compared with hoed surfaces, path/furrows reduce the time to HOF generation by about 85% and have ROCs that are six times higher. Access paths have the lowest K_s values of all watershed surfaces, but conveyance efficiency of HOF generated on these surfaces is low. Even recently created field paths are capable of reducing runoff generation time by 40–90% and producing sixfold increases in ROCs. Collectively, the data suggest that agricultural erosion rates are accelerated during the 12–18-month threshold period following abandonment and during storms where path-generated HOF interacts with adjacent planting surfaces. Despite having periods of increased HOF generation, the total HOF contribution from agricultural fields to the basin stream hydrograph is similar in magnitude to that of unpaved roads, which occupy 95% less land area.  相似文献   

长江重要堤防防渗与垂直防渗墙技术   总被引：2，自引：0，他引：2  

骆良胜 《华东地质学院学报》2001,24(2):140-143

历来长江中下游堤防洪水险情不断，堤基渗漏、堤身隐患、河岩崩塌是三大主要险情，而堤基渗漏尤其突出。本文阐述了堤基渗漏的地下渗流场，依渗流规律制定渗流控制措施，同时结合实际叙述了垂直防渗的主要措施－垂直防渗墙技术的多种工法。  相似文献   

Focused infiltration of snowmelt water in partially frozen soil under small depressions   总被引：5，自引：0，他引：5  

Masaki Hayashi  Garth van der Kamp  Randy Schmidt 《Journal of Hydrology》2003,270(3-4):214-229

Ephemeral puddles in small closed depressions can play an important role in the hydrology and ecology of many landscapes, by storing runoff water, recharging soil moisture and shallow groundwater, and by providing food and habitat for many organisms. Infiltration of snowmelt water under small depressions (<1000 m²) has been studied in the St. Denis National Wildlife Area in Saskatchewan, Canada, located within the northern glaciated prairie of North America where numerous depressions of varying sizes exist. The depressions stored most of the snowmelt runoff generated within their respective watersheds. The water level in a typical depression declined at 0.6 mm/h while the underlying frozen soil was thawing. This rate was likely limited by the rate of downward movement of the thawing front, which was functioning as a moving impermeable boundary. The rate of thawing was controlled by the external energy input from the ground surface. Standing water in depressions efficiently trapped incoming radiation and conducted it to the thawing front. The recession rate increased to 1.1 mm/h when the soil under the depression thawed completely. The recession rate at this later stage appears to be limited by the hydraulic conductivity of the subsoil (0.04–4 mm/h), which is much smaller than the topsoil conductivity (10–20 mm/h).  相似文献   

Numerical analysis of simultaneous heat and mass transfer during infiltration into frozen ground   总被引：1，自引：0，他引：1  

Litong Zhao  Donald M. Gray  David H. Male 《Journal of Hydrology》1997,200(1-4):345-363

This paper concerns heat transfer and water infiltration into a homogeneous, unsaturated, frozen soil. A numerical analysis of the processes, which is based on the local volume averaging formulation of transport phenomena in porous media, is described. Simultaneous heat and mass transfers with phase changes are considered. The results of the simulations provide an insight into the mechanics of the infiltration process. They suggest that infiltration involves primarily two flow regimes, a transient regime and a quasi-steady-state regime. Once the quasi-steady-state regime is reached, the energy needed to increase soil temperature at depth is supplied by latent heat released from freezing of water in the upper layers of soil. The effects of surface saturation, initial soil saturation and initial soil temperature on infiltration are examined.  相似文献   

文峪金矿床505脉矿化特征及构造控矿规律     

王可勇  范永香  高秋斌 《地质与资源》1997,6(4):270-277

505脉总体走向270~310°,呈透镜体状、扁豆状以尖灭再现或尖灭侧现的形式产出.505脉为一典型的具多金属硫化物含金石英脉.含金矿物主要是黄铁矿,其次为方铅矿和黄铜矿.黄铁绢英岩化是金矿化的重要标志.控矿构造有4次脉动,与其对应,505脉分4个成矿阶段,主要是Ⅰ、Ⅱ阶段及Ⅰ、Ⅱ、Ⅲ阶段叠加的部位成矿最好.505脉受一近东西向脆-韧性剪切带控制.矿体主要产于断裂的85~90°走向段和倾角为小于45~50°的缓倾段.这些部位也是多次矿化叠加、矿体厚度大、矿石品位高的部位,这些地段也是工业矿体产出的地段.  相似文献   

Behaviour of Different Molecular-weight Fractions of DOC of Elbe River Water during River Bank Infiltration     

U. Ludwig  T. Grischek  W. Nestler  V. Neumann 《洁净——土壤、空气、水》1997,25(3):145-150

This paper reports changes in dissolved organic carbon concentration β(DOC) and the relation between UV-active and non-UV-active components determined for Elbe river water and river bank infiltrate in the Torgau river basin between 1992 and 1994. Using an ultrafiltration method, the fractionation of the DOC content was obtained for the fractions > 10 000 g/mol, 1 000…10 000 g/mol, and < 1 000 g/mol. The spectral absorption coefficient at 254 nm a₂₅₄ of the molecular-weight fractions was also measured. The mean total DOC concentration of Elbe river water decreased from 6.0 mg/L to below 3.9 mg/L along two investigated flowpaths. Two thirds of the decrease occurred within the first few metres of the river bed and one third along the 350 m length of the groundwater flowpaths. The a₂₅₄ values showed a significant decrease from 14.8 1/m in Elbe river water to 7.8 1/m in the aquifer. Along a flowpath, the proportion of low-molecular weight fraction of DOC increased, the proportion of high-molecular weight fraction decreased, and the proportion of the 1 000…10 000 g/mol molecular-weight fraction remained relatively stable. The Elbe river water contained the main portion of UV-active compounds in the fraction 1 000…10 000 g/mol, and this was also the case for samples of river infiltrate. For the high-molecular weight fraction, mainly non-UV-active compounds were attenuated in the river bed sediment.  相似文献   

暖季强降雨对多年冻土南界斜坡路基稳定性影响分析     

段东明  沈宇鹏  张鲁新 《工程地质学报》2008,16(2):250-254

青藏铁路在多年冻土南界地区,夏季强降雨后的入渗,不仅破坏了冻土路基内地温场,降低了土体的强度,同时入渗产生的渗透压力降低了斜坡路基的稳定性。文章采用有限元对青藏铁路安多段多年冻土斜坡路基进行降雨入渗的模拟,并将渗流分析结果作为路基稳定性计算的水力条件。计算结果表明,该冻土斜坡稳定性系数在降雨结束20h内持续变小,而最小值出现在降雨后2d左右。  相似文献