鱼塘的夏秋管理

夏秋季节是鱼类生长最佳时期,但此时气温高、水质易恶化,水中溶氧低,极易发生死鱼。所以,夏秋季节鱼塘管理工作要注意以下几点: 1.合理施肥投饵:夏秋季节要“看天、看水、看鱼”施肥。天气晴朗、气压高,池塘水质肥、活、爽,鱼类活动、摄食力强时,可按常规施肥;天气闷热、气压低,池塘水质过肥,鱼类活     

题“首都作家绿化基地”

文人先富起来的并不多就像陡子峪这个贫困的山区陡子峪小学的学生娃子们站在早春的风里迎接我们而我们带给他们的只是一些书籍、电脑、衣物什么的面对他们期待的目光心跳加速,无以面对     

图观

<正>俄罗斯最大水电站冰封奇景1月31日,俄罗斯最大水电站——萨扬-舒申斯克水电站遭冰封。该电站位于西伯利亚地区哈卡斯共和国境内。近日该地区连遭寒     

客土喷播技术在矿山地质环境治理中的应用

治理矿山为露天开采矿山,坡面表层岩石风化破碎严重,基本无植被覆盖,易发生崩塌落石灾害。应用客土喷播技术,在岩石边坡上打锚杆、铺设铁丝网,采用专门喷播设备喷播有机基材及植物种子,加盖无纺布快速养护形成边坡生态防护层。边坡表面形成保护层及与表土相近的生长基础,破损山体边坡得到绿化,能起到涵养水源、保持水土、调节气候和净化大气的作用,具有巨大的生态环境效益。     

小水电站环境影响评价内容探讨

小水电站工程环境影响评价按有关规范规定为报告表，但其大纲内容不适合山区小水电站环评。通过总结30余座小水电站环评实践，探讨了小水电站环评基本内容应包括：环境影响分析与预测评价、涉及生态影响因子范围、环境保护措施、公众参与等，从技术角度能满足环保管理部门的审批要求。     

各省动态

福建:试点退出小水电站福建省近日在生态县长汀试点实施东坑和江坊2座小水电站退出,以保持水土、涵养水源、改善水质、美化环境。2015年,福建省首先选择长汀县和永春县,作为小水电退出试点县。福建将出台政策,引导和鼓励安全隐患重、效益低、水生态影响大的水电站实施退出。福建"十三五"拟规划完成1000座小水电退出工作,改善约200条河流的水生态。     

西宁市重大地质灾害隐患分布规律研究

西宁市地处我国黄土高原与青藏高原过渡带,特殊的自然地理环境、强烈的人类工程活动和晚期构造运动的差异性,在湟水及其支流平原两侧的低山丘陵前缘高陡斜坡严重失稳,滑坡、崩塌、泥石流灾害频繁发生,使西宁市成为我国受地质灾害威胁较严重的省会城市之一。文章通过对西宁市地质环境条件和重大地质灾害隐患分析,认为西宁市重大地质灾害隐患在空间上具有相对集中的分布规律。     

干旱生态敏感区水电站环境影响后评价指标体系研究

针对干旱生态敏感区水电站环境影响后评价的要求,设计备选指标集,采用频次分析法进行指标初选,采用专家咨询法进行指标精选,建立由4项二级指标、14项三级指标构成的干旱生态敏感区水电站环境影响后评价指标体系,采用层次分析法给每个指标赋予权重。将该评价指标体系用于某水电站建设的实例分析,结果表明,水电站运行以来总体上有利影响大于不利影响,并且在可接受范围内,其不利影响可以采取人工辅助措施加以避免或减缓。评价结果符合实际,该指标体系具有针对性和一定的实用性。     

水电站建设对水环境容量的影响研究

水电站建设影响河道水环境容量。为研究水电站建设对水环境容量的影响,本文以汉阳水电站为例,采用一维水环境容量计算方法,计算相应河段建库前后水环境容量,并分析了降解系数的取值对水环境容量的影响。结果表明建库后水流流速减缓,污染物降解时间增加,从而增大水环境容量;而水流流速减缓,降解系数减小,从而减小水环境容量。在二者共同作用下,汉阳水电站建库前后水环境容量变化不大。     

西宁地区近地面臭氧(O3)浓度的变化特征及气象条件分析

文章给出了西宁地区2007年4月～2008年12月近地面臭氧浓度的季节变化及日变化.分析了2008年气象因子与地面臭氧浓度的关系.结果表明:西宁地区地面臭氧浓度与云天状况、风向风速、相对湿度、气压等要素的变化比较明显.当西宁地区出现晴天、风速较大、偏E风、气压较低、湿度小时,为出现高地面臭氧浓度的天气条件.与相距90公里处的瓦里关全球大气本底站资料相比,其季节变化及日变化明显不同.     

Impact of mining industries on the groundwater level fluctuation in Singrauli coalfield area by using remote sensing and GIS,India

The coal mining industries influence hydro-geological parameters, which affect the aquifer recharge in the coal mining areas. This research aimed to evaluate the impact of various hydro-geological parameters on fluctuation of groundwater level in the study area. The various hydro-geological parameters such as soil, geology, drainage pattern, elevation and slope have been considered to accomplish the objective. A comparative analysis was performed by comparing the groundwater level fluctuation (WLF) map with the GIS-based various hydro-geological parameter maps to assess the combined influence of different hydro-geological parameters on groundwater level fluctuation. A total of eighty-six (86) dug-wells were chosen to monitor the level of the groundwater for around ten blocks of Singrauli coalfield, and these wells were examined during the months of dry and wet seasons for 2016. Based on the comparative analysis between the WLF map and thematic maps of various hydro-geological parameters, it has been found that WLF in the south-western and some portions of the north-eastern showed moderate to a higher value. This may be because most of the non-hilly areas come under gentle to moderate slope category, with lower elevation in the area forming the suitable hydro-geological condition for recharging groundwater. It was observed that the northwest, south-east and central part of the study area showed lower WLF, which may be due to the presence of overburden dump, presence of higher elevation and steep slope. Thus, the combined effect of slope, elevation, geology, drainage and mining activities on the WLF in the study region is moderate.     

Assessing slope stability in unplanned settlements in developing countries

Unplanned housing in developing countries is often located on steep slopes. Frequently no building code is enforced for such housing and mains water is provided with no drainage provision. Both of these factors can be particularly significant in terms of landslide risk if, as is so often the case, such slopes lack any planned drainage provision. There is thus a need to develop a model that facilitates the assessment of slope stability in an holistic context, incorporating a wide range of factors (including surface cover, soil water topographic convergence, slope loading and point source water leakage) in order that appropriate advice can be given as to the general controls on slope stability in such circumstances. This paper outlines a model configured for this specific purpose and describes an application to a site in St. Lucia, West Indies, where there is active slope movement in an unplanned housing development on relatively steep topography. The model findings are in accord with the nature of the current failure at the site, provide guidance as to the significance of slope drainage and correspond to inferences drawn from an application of resistance envelope methods to the site. In being able to scenario test a uniquely wide range of combinations of factors, the model structure is shown to be highly valuable in assessing dominant slope stability process controls in such complex environments.     

乌昌地区污水综合利用北灌荒漠防护林方案初探

根据新疆天山北坡经济带区位优势以及北坡地势南高北低、干旱少雨等地理气候特点,结合乌昌地区的发展现状和规划目标,将乌昌地区城市生活污水,用于灌溉北部荒漠防护林。对构建片、带、网相结合的绿色屏障,阻挡沙漠南移,改善乌昌地区生态环境具有一定的缓解作用,为解决干旱地区城市污水的综合利用做了有益的探索研究。     

ESTIMATING DRAINAGE AREA ON STEEP UNIFORM SLOPES1

ABSTRACT: A study was conducted to derive a simple procedure for estimating the tributary drainage area that may potentially develop at the base of a uniformly graded, steep slope. Data were extracted from a nil development flume study in which 112 rills and their tributary drainage areas were documented. The tributary drainage area for each rill was correlated to the slope length and the slope gradient. The findings are considered applicable to planar, convex, and divergent slopes with lengths of up to 130 m. Field verification is needed to extend the applicability of the relation.     

陡坡地集流聚肥梯田技术的应用

本文根据径流农业和水土保持综合治理的基本原理,以及对辽西部陡坡地资源的调查研究,介绍了陡坡地集流聚肥梯田的内涵,集流,集流效果及其优化设计参数的确定。     

Response of turf and quality of water runoff to manure and fertilizer

Manure applications can benefit turfgrass production and unused nutrients in manure residues can be exported through sod harvests. Yet, nutrients near the soil surface could be transported in surface runoff. Our research objective was to evaluate responses of bermudagrass [Cynodon dactylon (L.) Pers. var. Guymon] turf and volumes and P and N concentrations of surface runoff after fertilizer or composted manure applications. Three replications of five treatments were established on a Boonville fine sandy loam (fine, smectitic, thermic Vertic Albaqualf) that was excavated to create an 8.5% slope. Manure rates of 50 and 100 kg P ha(-1) at the start of two monitoring periods were compared with P fertilizer rates of 25 and 50 kg ha(-1) and an unfertilized control. Compared with initial soil tests, nitrate concentrations decreased and P concentrations increased after two manure or fertilizer applications and eight rain events over the two monitoring periods. The fertilizer sources of P and N produced 19% more dry weight and 21% larger N concentrations in grass clippings than manure sources. Yet, runoff volumes were similar between manure and fertilizer sources of P. Dissolved P concentration (30 mg L(-1)) in runoff during a rain event 3 d after application of 50 kg P ha(-1) was five times greater for fertilizer than for manure P. Observations during both monitoring periods indicated that total P and N losses in runoff were no greater for composted manure than for fertilizer sources of P at relatively large P rates on a steep slope of turfgrass.     

沱江流域农村径流污染因素分析及防治措施

本文分析了沱江流域农村径流的污染因素和农村径流对沱江的影响,并提出了防治径流污染的措施,通过两年逐月沱江监测数据表明,雨季沱江受到农村径流污染。根据分析,降雨冲刷时段集中、地形坡度加剧径流冲刷、农作物种植安排抗蚀能力差、农药化肥流失严重等是造成沱江流域农村径流污染的主要因素。在农村径流污染因素分析的基础上提出防治农村径流污染的措施。     

Upland Controls on the Hydrological Functioning of Riparian Zones in Glacial Till Valleys of the Midwest1

Abstract: Identifying relationships between landscape hydrogeological setting, riparian hydrological functioning and riparian zone sensitivity to climate and water quality changes is critical in order to best use riparian zones as best management practices in the future. In this study, we investigate water table dynamics, water flow path and the relative importance of precipitation, deep ground water (DG) and seep water as sources of water to a riparian zone in a deeply incised glacial till valley of the Midwest. Data indicate that water table fluctuations are strongly influenced by soil texture and to a lesser extent by upland sediment stratigraphy producing seeps near the slope bottom. The occurrence of till in the upland and at 1.7‐2 m in the riparian zone contributes to maintaining flow parallel to the ground surface at this site. Lateral ground‐water fluxes at this site with a steep topography in the upland (16%) and loam soil near the slope bottom are small (<10 l/d/m stream length) and intermittent. A shift in flow path from a lateral direction to a down valley direction is observed in the summer despite the steep concave topography and the occurrence of seeps at the slope bottom. Principal component and discriminant analysis indicate that riparian water is most similar to seep water throughout the year and that DG originating from imbedded sand and gravel layers in the lower till unit is not a major source of water to riparian zones in this setting. Water quality data and the dependence of the riparian zone for recharge on seep water suggest that sites in this setting may be highly sensitive to changes in precipitation and water quality in the upland in the future. A conceptual framework describing the hydrological functioning of riparian zones on this setting is presented to generalize the finding of this study.     

Developing Restoration Planting Mixes for Active Ski Slopes: A Multi-Site Reference Community Approach

Downhill ski areas occupy large expanses of mountainous lands where restoration of ecosystem function is of increasing importance and interest. Establishing diverse native plant communities on ski runs should enhance sediment and water retention, wildlife habitat, biodiversity and aesthetics. Because ski slopes are managed for recreation, ski slope revegetation mixes must consist of low-stature or herbaceous plants that can tolerate typical environmental conditions on ski slopes (high elevation, disturbed soils, open, steep slopes). The most appropriate reference communities for selecting ski slope revegetation species are thus successional, or seral plant communities in similar environments (i.e., other ski slopes). Using results from a broad-scale reference community analysis, I evaluated plant communities naturally occurring on ski slopes from 21 active and abandoned ski areas throughout the northern Sierra Nevada to identify native plant species suitable for use in ski slope restoration. I constructed a baseline planting palette of regionally appropriate plant species (for restoration of either newly created or already existing ski runs) that is functionally diverse and is likely to succeed across a broad range of environments. I also identify a more comprehensive list of species for more specialized planting mixes based on site-specific goals and particular environmental settings. Establishing seral plant communities may be an appropriate restoration goal for many other types of managed lands, including roadsides, firebreaks and utility rights-of-way. This study describes an ecological (and potentially cost-effective) approach to developing restoration planting palettes for such managed lands.     

官地水电站本底生态调查与施工期生态调查成果的对比与分析

本文通过官地水电站施工期陆生、水生生态调查与环评阶段调查成果的对比和分析,验证了环评对施工期生态影响的预测结论、环评提出的环保措施的合理性,证明了施工期实施生态保护措施的必要性以及施工期生态调查的重要意义。