嫩江大堤植物根系固土护堤功能研究

通过对嫩江大堤护坡植物根系及土壤抗冲、抗蚀及抗剪强度的测定分析,发现同一地段土壤的抗冲、抗蚀（水稳性）指数及抗剪强度均是表土层大于底土层。植物根系有较强的固持土壤功能,抗冲指数与根长、根量间有明显的相关性,单相关系数分别为０９１４６和０８１９７。有机质含量高的土壤抗蚀性强,水稳性指数大,土壤抗蚀性与有机质含量间的相关系数为０９１３２,与根长和根量的相关性相对较低,单相关系数分别为０８１３７和０８０９１。土壤稳定性与植物根量关系密切,根量大,其抗剪强度就大,相关系数为０９８１４。在现有的植物中,牛毛草地抗蚀能力最大,其固土护坡护堤功能最强,应大力推广。     

江西省堤防护坡形式现状及其研究展望

堤防工程是防洪体系的重要组成部分,其护坡形式是防洪等级、水土保持及景观要求的综合反映。根据江西省堤防护坡的现状和主要特点,综述了江西省堤防护坡的主要形式,总结提炼了传统硬质护坡、自然恢复边坡和生态护坡等护坡形式的优缺点及其适用范围,指出在以后应该加强堤防生态护坡的研发工作,特别是优良护坡草种的筛选和培育工作。     

混凝土网格梁、板沙堤护坡技术

阜新县河床受地质影响,多发生于前震旦纪花岗岩山区,河床质为沙粒.在小流域治理过程中,用这些沙质材料筑成的堤坝,其透水性强,稳定性较差,堤坝表面抗冲能力弱,容易被洪水冲刷成岸坎,失去其防护作用.另外,从生态建设方面也存在不易绿化等问题.为此研究混凝土网格梁、板组合堤防护坡技术,以提高沙质堤防的稳定、绿化问题.     

综合评分法在护坡方案优选中的应用

河道护坡是河道防洪工程中一项量大面广的基础设施。结合河道护坡工程实例,选择了浆砌石挡土墙护坡、混凝土面板护坡、混凝土模袋护坡、铰接式连锁砖4种护坡方案,通过对4种方案进行优缺点比较,提出了利用综合得分的方法对4种护坡方案进行优选,在比较分析各方案得分的基础上,评选出最佳护坡方案为铰接式连锁砖护坡。     

平原区河道生态治理之我见

黑山县地处绕阳河下游地区,主要河流有绕阳河等,且属季节性河流。河床坡度小,含沙量大。由于近年来连续干旱少雨,河水几乎断流,由此而产生了麻痹思想,导致除了在防洪堤内仅留出主河床外,在两侧滩地全部栽植了杨树,已构成行洪障碍。历史洪水固然可鉴,但季节性河流,决定了岸滩的空置;百年不遇的洪水必然少见,若河滩地闲置无用,也是一种资源的浪费。河道生态治理的关键在于调整规划设计理念,分级防洪标准一线穿,设计多阶复式断面,一阶滩地短期用,行洪漫流无风险;二阶滩地年际用,超标洪水还河滩。河岸堤防确定合理治导线;主洪槽保自然,一阶护堤随势弯,二阶护堤直顺川。生态护堤很环保,绿化、经济又景观,河流生态若平衡,人水和谐社平安。     

土工模袋在堰塘护坡工程中的应用

土工模袋护坡法普遍应用于取水工程、护坡工程。其特点是不仅保证工程整体性可靠,一次性施工面积大、速度快,且克服了干砌石护坡法的弱点,简化了施工工艺和施工流程。模袋混凝土强度一般为C15～C30。无论在技术上,乃至经济上都有突出的优越性。其关键技术在于编织物选择、模袋厚度的确定、模袋加工、铺设及混凝土充灌。2010年于普兰店市大刘家镇小山村进行施工,实践证明:护坡整体稳定,质量满足抗冲、抗冻设计要求。应用土工模袋护坡是一种行之有效的施工方法。     

渭河水患成因与治理对策初探

渭河水患已严重影响到渭河下游两岸人民生命财产安全.通过对历史洪峰流量与洪水水位的对比分析、文献资料分析和实际调查等方法,得出渭河水患的主要成因是:渭河上游黄土高原地区毁林开荒,造成水土流失,加大了泥沙量;下游两岸防洪堤坝的修建,限制了河水流动范围,影响行洪泻洪,造成泥沙沉积.黄河三门峡工程的修建,加剧了泥沙沉积,抬高了河床高度,使渭河成为地上悬河,遇到洪水极易毁堤,形成水灾.治理渭河首先要理清思路,在方法和措施上要有突破和创新,在治渭方略上要以疏为主,疏堵结合,关键是要降低河床高度.要综合治理,工程措施与生物措施并举,科学调水调沙,退田还河.惟有这样,方可确保渭河安澜.     

新疆和田县段河滩地水土保持综合治理对策

玉龙喀什河流域由于河岸防护工程较少、抗冲能力差,河道防御标准低,洪水每年对河岸造成很大的损失,严重危害当地群众的生命和财产安全。为了有效治理河道,稳固当地群众积极发展农业,加快经济建设步伐,提高居民生活水平,当地水保部门利用水土保持综合治理较少的投资,结合玉龙喀什河和田县段的实际情况,通过粉细沙筑丁坝,同时对丁坝坝头用沉桩进行有效保护,并且让沿线丁坝形成一定规模的治理对策,其护岸和淤沙的效果非常好,同时在淤沙处结合植物措施,对河道的整治也起到了非常好的效果。     

泥石流防治工程混凝土材料的抗冲磨性能

[目的] 开展在混凝土中复掺纳米二氧化硅、微硅粉、聚丙烯纤维等材料,增强工程耐磨性的试验研究,探讨复掺材料掺量变化影响抗冲磨强度的规律,旨在为泥石流防护工程建设中抗冲磨混凝土的配合比设计提供科学参考。[方法] 采用正交试验设计的水下钢球法对混凝土试件进行水下冲磨试验,得出了复掺纳米二氧化硅、微硅粉、聚丙烯纤维的混凝土试件的抗冲磨强度。[结果] 在选定的掺量范围内,混凝土试件的抗冲磨强度随纳米二氧化硅的增加先增大再减小,在掺量为1.5%时达到最大值;随微硅粉的增加而增大,在掺量为12%时达到最大值;随聚丙烯纤维的增加先减小再增大,在掺量为1.8 kg/m³时达到最大值;随着引气剂的增加先减小再增大,在掺量为0.005%时达到最大值。[结论] 影响混凝土抗冲磨性能最为显著的因素是纳米二氧化硅掺量,其次是聚丙烯纤维,再次是微硅粉,最后是引气剂。     

河道生物护堤固岸技术的实践与探讨

以汾河下游运城段为例 ,提出了平原冲积性复式河道生物护堤和生物固岸护弯新模式。对防洪土堤 ,采用优化栽植乔灌木林带建设的方法 ,削能防冲 ,固坡护堤 ;对弯道险段 ,在岸坡及河底 ,插植矮化的紫穗槐、绵柳等灌木林带 ,控制河势 ,稳定主槽 ,防止其畸形发展。并提出了护堤林带可持续发展的管理措施。     

沣河综合治理与橡胶坝工程效益研究

针对沣河咸阳段存在河堤标准低,质量差,险段多,局部段堤距较窄,堤身单薄且未砌护,堤线布置不合理等问题。提出了沣河综合治理工程和新型橡胶坝引水防沙工程的基本模式,解决了以往洪水泛滥,河床滩面裸露,两岸杂草丛生,河堤内乱倒垃圾,水体污染严重的难题。研究结果表明沣河上橡胶坝的修建将产生明显的经济、环境和社会效益。     

石坎梯田的优化设计

通过对石坎梯田断面要素和工程量的分析,以田坎高度和田坎侧坡坡率作为设计变量,以每公顷梯田的造价为目标函数,提出了石坎梯田的通用优化设计数学模型,并进行了实际优化计算。优化设计结果和常用的石坎梯田规格相比,优化设计的石坎梯田要比常用规格安全经济得多。     

The Vertical Distribution of Soil Seed Bank and Its Restoration Implication in an Active Sand Dune of Northeastern Inner Mongolia,China

Although the functions and characteristics of soil seed banks in topsoil layers have been described for various ecosystems, the spatiotemporal pattern of the seed bank in deep soil and its ecological implications for vegetation restoration of active sand dune have not been fully explored. In 2007 and 2008, seed densities with regard to dune position, soil depth and season were investigated on an active and a stabilized sand dune of northeastern Inner Mongolia, China. Seeds in the 0–10 cm topsoil layer accounted for 60% of total soil seed bank on the stabilized sand dune, while more than 40% of seeds were stored in the 50–100 cm layers on the active sand dune. Seed density declined significantly with soil depth on the stabilized sand dune, but it was relatively constant across the 0–100 cm soil profile on the active sand dune. Seed density fluctuated with soil depth on the active sand dune suggesting that seeds were either relocated upward or downward over time. Seeds of annual non‐psammophytic species accounted for the majority of soil seed bank on the stabilized sand dune, while pioneer psammophytes contributed more to the soil seed bank of the active sand dune. Our data suggest that seeds in the deep soil layers of active sand dunes account for a large proportion of the whole soil seed bank. Because of the effect of wind erosion, seeds in deep soil could be gradually exposed to shallow soil layers and potentially contribute to population recruitment and vegetation restoration on active sand dunes. Copyright © 2015 John Wiley & Sons, Ltd.     

黄河中游多沙粗沙区土地利用与覆盖变化分析

黄河中游多沙粗沙区是黄河中下游淤积泥沙的主要来源区,所以研究多沙粗沙区的土地利用与覆盖变化具有重要的现实意义。利用具有时间序列的多沙粗沙区土地利用图,在地理信息系统的支持下,分析了该区1980年到1997年间土地利用的时空变化规律,以及土地利用、土地覆盖变化的驱动因子,并结合多沙粗沙区的自然特征,对该区的水土保持、生态环境建设提出了一些建议。     

黄河中游多沙粗沙区治理对黄河水资源的影响

黄河中游多沙粗沙区,特别是粗泥沙集中来源区的水土流失是黄河泥沙,特别是粗泥沙的主要来源,强化对该区的治理是减少入黄泥沙,特别是粗泥沙,效果最为明显,通过综合治理,在减少入黄泥沙的同时,也必然要减少入黄水量。但应看到,因减少了入黄泥沙,特别是粗泥沙,也会减轻下游河床淤积,因而减少了为维持下游"河床不抬高"而消耗的输沙用水量。研究表明,多沙粗沙区,特别是粗泥沙集中来源区治理程度越高,所节约的输沙水也越多。可以说,加强该区治理,可间接为黄河"增加"水资源。     

The Influences of Storage and Further Purification on Residual Concentrations of Pharmaceuticals and Phthalate Esters in Drinking Water

This paper reports about the modification of sand and fumed silica with titania in order to obtain a photocatalytic active material for the degradation of pollutants. The coating process was performed based on the sol–gel method. Tetrapropylorthotitanate was used as the titania precursor to apply a nanoscaled layer on sand grains. For silica fume, the coating process was varied. Various amounts of tetrapropylorthotitanate were used to obtain different coating thicknesses and to identify the maximum amount of titania that could be loaded on the material. All samples showed high photonic efficiencies in the degradation of nitrogen monoxide despite their low titania quantities, which were identified via x-ray fluorescence analysis. Some samples showed higher photonic efficiencies than commercial Degussa P25. Due to the preparation method, calcination of the sand composites was not necessary to yield a crystalline coating which was responsible for the high photocatalytic activity. However, silica fume composites had to be calcined possibly due to variation in the preparation method. Scanning electron micrographs revealed the structured morphology of all specimens. Energy dispersive x-ray analysis identified nanoscaled titania particles on the sand surface that could not be observed only via SEM. The results of this research are especially interesting for large scale applications of photocatalysts. As industrial sand and silica fume used are low cost materials, this new kind of photocatalyst can be applied in higher quantities and distributed onto larger areas, while saving costs at the same time.     

Restoration of the Rivers in Israel's Coastal Plain

Israel's chronic water shortage has aggravated problems of river pollution, as almost no dilution of inadequately treated wastewater takes place. Since the early 1990s, large investments were made to build new wastewater treatment plants, designed to produce effluents of secondary quality or better. Consequently, it became of interest to examine the possibility of using tertiary treated effluents as a water source for rehabilitation of aquatic habitats. A survey of water quality in clean and polluted segments of Israel's coastal rivers was initiated, including analyses of riverbed sediments. Although many segments are still heavily polluted, there are examples of measurable improvement in water quality, which should lead to better sediment quality. It is argued that sediments serve both as a memory bank of past pollution events and as an ongoing source of anaerobic and toxic compounds, such as sulfides and ammonium compounds. Their chemical compositions are, therefore, of much importance for river restoration processes and monitoring.     

黄河乌兰布和沙漠段沿岸风沙流结构与沙丘移动规律

为明确黄河乌兰布和沙漠段沿岸的风沙活动及沙丘移动特征,该文以黄河乌兰布和沙漠段沿岸的流动沙丘为研究对象,采用野外观测与实验室分析相结合的方法对沿岸沙丘的起沙风况、沙物质组成、风沙流结构及沙丘移动规律进行初步的定量研究。结果表明:起沙风的主风为西南—西风,集中于3-5月份,且5～6m/s风占起沙风的50.26%;沙物质粒径以细砂(0.1～0.25mm)为主,沿黄段沙丘粒径极细砂以下(≤0.1mm)的沙物质粒径组成比沙漠腹地减少8.92%;距地60cm高度范围内,81.75%的沙物质在0～10cm高的气层中通过。在沙丘的不同部位上,相对输沙量与高程之间有着良好的幂函数关系;沙丘向前移动的距离为8.19m/a,主要发生在3-5月份。该研究结果可为合理计算入黄风积沙量及完善黄河沿岸综合防护体系提供科学依据。     

黄河首曲重大生态功能区护岸林建设问题探讨

分析了河岸防护林改变区域小气候、巩固河岸、保持水土、防风固沙、改良土壤、湿地保护、提供饲料、薪材和增加收入、提高畜牧业生产力、丰富和改善高寒区景观等作用,系统阐述了加强河岸防护林建设的重要性,针对性地提出了河岸防护林树种组成单一、体系结构不够完整、自然因素恶劣等护岸林建设问题,并提出了进一步发展建设的对策,在黄河首曲重大生态功能区的环境建设中加强黄河护岸林建设,对于黄河首曲生态环境的治理、恢复、重建和改善具有十分重要的意义。     

Distribution, species composition and management implications of seed banks in southern New England coastal plain ponds

Buried seeds that germinate during periods of low water or water level drawdown can play important roles in shaping plant community composition, community dynamics and species richness in ecosystems with fluctuating water levels. Northeastern US coastal plain ponds have fluctuating water levels and contain a characteristic shoreline flora that contains many rare plants. The objectives of this study were to: (1) test whether geographically distant ponds in Cape Cod and Martha’s Vineyard had distinct seed banks, (2) determine if hydrologic status as permanent and ephemeral ponds led to differences in seed banks, and (3) examine seed diversity and seed abundance across gradients of shoreline elevations and sediment characteristics. Viable seeds of 45 plant species were identified from nine ponds. Native species dominated pond-shore seed banks and made up 89-100% of all species. There was high overlap in seed bank composition across hydrological classes and geographic regions. One hydrological class captured 73-76% of total species and one geographical region captured 69-78% of the total species recovered from the entire suite of seed bank samples. Seeds were relatively evenly distributed along the shorelines of ephemeral ponds but seed diversity and abundance were lower at low elevations in permanent ponds. Results suggest that strategies to protect pond shorelines to capture maximum diversity of coastal plain pond plants contained in pond sediment seed banks should be implemented across pond hydrologic classes and across a wide geographic area. Shoreline seed distributions indicate that ground-water withdrawals or climate changes that lower pond water levels in permanent ponds will reduce the diversity and abundance of plants recovered from seed banks by shifting water levels to a shoreline zone of high sediment organic matter where seed densities are lower. This effect will be much less in ephemeral ponds where seed diversity and abundance on pond bottoms was high.