THE TWO‐DIMENSIONAL UPLAND EROSION MODEL CASC2D‐SED1

ABSTRACT: The two‐dimensional soil erosion model CASC2D‐SED simulates the dynamics of upland erosion during single rainstorms. The model is based on the raster‐based surface runoff calculations from CASC2D. Rainfall precipitation is distributed in time and space. Infiltration is calculated from the Green‐Ampt equations. Surface runoff is calculated from the diffusive wave approximation to the Saint‐Venant equations in two‐dimensions. Watershed data bases in raster Geographical Information System (GIS) provide information on the soil type, size fractions, soil erodibility, cropping management, and conservation practice factors for soil erosion calculations. Upland sediment transport is calculated for the size fractions (sand, silt, and clay), and the model displays the sediment flux, the amount of suspended sediment, and the net erosion and deposition using color graphics. The model has been tested on Goodwin Creek, Mississippi. The peak discharge and time to peak are within ± 20 percent and sediment transport rates within ?50 percent to 200 percent.     

Evaluation of rainfall erosivity in Bheta Gad catchment, Kumaun Hills of Uttar Pradesh, central Himalayas

The importance of the size of raindrop in causing soil detachment and splash has long been recognized, although the total energy expended on erosion by splash may be small. The aggressiveness of rainfall or its capacity to cause detachment can be expressed in terms of drop size, rainfall intensity and kinetic energy or momentum. An attempt has been made to determine the rainfall erosivity (EI) of two gauged stations where continuous rainfall recorders were installed, on the basis of rainfall characteristics. Thus, the relationship between average storm EI₃₀ (rainfall erosivity for 30 minutes interval) values and average depths of rainfall could be developed for the Bheta Gad basin of the Gomati River in the Hindu-Kush Himalayas. The analysis has revealed that if factors other than rainfall remain constant, soil splash erosion from cultivated fields is directly proportional to the rainstorm parameter identified as EI.     

贵州省矿业生产诱发喀斯特石漠化的机理与治理对策探讨

文章对贵州省矿产开发导致的喀斯特石漠化现状及机理进行了调查分析,发现:贵州大宗开采的煤、磷、铝土、金、铅锌、重晶石等矿产主要分布在碳酸盐岩分布区,赋矿层位均在碳酸盐岩所夹的碎屑岩中或碳酸盐岩中。矿产的开发导致水土流失、地下水位下降,排放的废气、废水使植被死亡或抑制其生长,导致了严重的石漠化,是人类强烈经济活动的直接结果。并对此提出了防治对策。     

模拟酸雨对混凝土影响的研究

采用周期浸泡和喷淋试验等２种加速腐蚀试验方法,分别研究ＰＨ为１．０、３．５、５．６和ＰＨ为１．０、ＳＯ＾２－４为０、０．０６、０．１ｍｏｌ／Ｌ等６种模拟酸雨对混凝土的影响。     

模拟酸雨对砂浆影响的研究

建立了周期浸泡法和喷淋试验法等两种加速腐蚀试验方法,并分别研究Ph为5.6、3.5和Ph为1.0、S²₄-为0、0.06、0.1、0.2mol/L六种模拟酸雨对砂浆的影响。研究结果表明：砂浆受蚀后强度降低,其下降的程度与材料中CaO和SO₃/CaO的比值成二元线性关系;酸雨中＋的侵蚀将使材料中CaO、MgO、Al₂O₃和Fe₂O₃组分流失,H⁺.和SO的协同作用,使材料中的SO₃/CaO的比值增大;受蚀后的砂浆其物相发生较大的变化,变化趋势是原［CaNa］［SiAI］₄0₈、KAISi₃0₈、0.62NaAISi_{208·0.38CaAl2等矿物晶体逐渐消失,而转化成CaSO4·2H2O、CaAl2i2O8、Ca－Fe－Al－S－Si－O,甚至体积更大的Ca3Al6O12·CaSO4。因此,酸雨对砂浆的影响,主要是H⁺侵蚀引起的溶解腐蚀和SO²4-侵蚀引起的膨胀腐蚀。}     

风蚀与环境若干问题及思考

本文从风蚀对植物生长环境的影响、风蚀与尘暴、人为活动与风蚀三个方面对风蚀与环境的关系进行了评述,并对今后的研究方向提出了建议.     

新型高分子抑尘剂的性能实验研究

为了进一步改善抑尘剂抑尘性能,自主研发了新型高分子抑尘剂。以阜新发电厂末煤为实验原型,对8组小煤堆 在自然条件下进行抑尘性能实验。研究其表面固化效果、耐水冲蚀性、抗风蚀性、流动性等主要性能,得出其在不同条 件下的最佳浓度配比。实验结果表明:新型抑尘剂具有良好的抑尘功能,其耐水冲蚀性和抗风蚀性随抑尘剂浓度增加而 增强。在多雨地区,抑尘剂溶液最佳浓度是3%,浓度大于3%时抑尘剂耐水冲蚀性随浓度增加效果不明显;在干燥多风地 区,当煤堆储存在30天以内时,抑尘剂溶液最佳浓度范围为1%~3%,储存30~50天时,最佳浓度范围为3%~4%,储存在50 天以上时,最佳浓度为5%。抑尘剂溶液流动性随浓度增加而降低,高浓度抑尘剂喷洒时不易实现均匀喷洒,浓度超过3% 的抑尘剂喷洒时需提前用低浓度溶液进行预湿润。     

公路建设中水土流失分析及对策建议

以天津地区公路建设为例,分析了公路建设过程中水土流失主要受降雨、植被的减少、地形、土壤、人工因素等方面的影响。根据水土流失方程式对公路施工前后水土流失的情况进行了分析,结果显示公路建成一般需要2~3年,由于植被的恢复,水土流失可恢复到施工前的水平,并且随着植被的生长,道路沿线的水土流失会比施工期减轻。     

Protecting River Corridors in Vermont1

Kline, Michael and Barry Cahoon, 2010. Protecting River Corridors in Vermont. Journal of the American Water Resources Association (JAWRA) 46(2):227-236. DOI: 10.1111/j.1752-1688.2010.00417.x Abstract: The Vermont Agency of Natural Resources’ current strategy for restoring aquatic habitat, water quality, and riparian ecosystem services is the protection of fluvial geomorphic-based river corridors and associated wetland and floodplain attributes and functions. Vermont has assessed over 1,350 miles of stream channels to determine how natural processes have been modified by channel management activities, corridor encroachments, and land use/land cover changes. Nearly three quarters of Vermont field-assessed reaches are incised limiting access to floodplains and thus reducing important ecosystem services such as flood and erosion hazard mitigation, sediment storage, and nutrient uptake. River corridor planning is conducted with geomorphic data to identify opportunities and constraints to mitigating the effects of physical stressors. Corridors are sized based on the meander belt width and assigned a sensitivity rating based on the likelihood of channel adjustment due to stressors. The approach adopted by Vermont is fundamentally based on restoring fluvial processes associated with dynamic equilibrium, and associated habitat features. Managing toward fluvial equilibrium is taking hold across Vermont through adoption of municipal fluvial erosion hazard zoning and purchase of river corridor easements, or local channel and floodplain management rights. These tools signify a shift away from primarily active management approaches of varying success that largely worked against natural river form and process, to a current community-based, primarily passive approach to accommodate floodplain reestablishment through fluvial processes.     

Ability of Remnant Riparian Forests,With and Without Grass Filters,to Buffer Concentrated Surface Runoff1

Knight, Kris W., Richard C. Schultz, Cathy M. Mabry, and Thomas M. Isenhart, 2010. Ability of Remnant Riparian Forests, With and Without Grass Filters, to Buffer Concentrated Surface Runoff. Journal of the American Water Resources Association (JAWRA) 46(2):311-322. DOI: 10.1111/j.1752-1688.2010.00422.x Abstract: Riparian forest buffers established according to accepted conservation practice standards have been recommended as one of the most effective tools for mitigating nonpoint source pollution. The midwestern United States is characterized by many kilometers of narrow, naturally occurring forests along streams. However, little is known about the relative effectiveness of these remnant forests compared with these newly established buffers. This study compared the ability of naturally occurring remnant forests with and without adjacent planted grass filters to buffer concentrated flow paths (CFPs) originating in crop fields along first- and second-order streams in three northeast Missouri watersheds. Remnant forests breached by runoff through CFPs were narrower than those that dispersed 100% of the CFPs. Remnant forests with adjacent grass buffers were nearly twice the width as those without grass filters. We also found that CFPs, which developed within remnant forests and at the base of in-field grass waterways, were potential sources of sediments to streams. Methods to mitigate these CFPs warrant further investigation. Our study suggests that although these natural remnant forests provide substantial buffering capacity, both improved management and/or the addition of an adjacent grass filter would improve water quality by reducing sediment loss to streams. Inferences can be used to inform the design and management of similar conservation buffer systems within the region.