Impacts of river recharge on groundwater level and hydrochemistry in the lower reaches of Heihe River Watershed, northwestern China

Water resources have been overexploited for agricultural irrigation and industrial production in the upper and middle reaches of the Heihe River, northwestern China. Due to inadequate water resources management, the runoff entering into the lower reaches has been continuously reduced in recent years. The Heihe River is the primary recharge source for the groundwater of the lower reaches, so the decrease in runoff has caused the groundwater level to decline. As a result, a series of ecological and environmental problems has now appeared in the lower reaches, including river-flow interruptions, drying up of associated lakes, degeneration of vegetative cover and so on. In view of these issues, the National Water Diversion Project was put into practice in July 2000. It has significantly increased the quantity and frequency of flows entering into the lower reaches of the Heihe River, and has recharged the groundwater and improved the water quality to some degree along the length of the river. The water deliveries have had obvious influences on the groundwater in the lower reaches. The groundwater level increase and groundwater quality improvement have been of great benefit in restoring the ecological environment that was destroyed in past years.     

三塘湖盆地牛东石炭系火山岩示顶底构造特征、成因及地质意义

三塘湖盆地牛东区块石炭系卡拉岗组火山岩中发育的示顶底构造,类同于碳酸盐岩发育的示顶底构造。该火山岩中的示顶底构造主要发育于火山岩的气孔及自碎缝中,其下部主要为渗滤泥沉积,上部常为结晶的钠沸石或其它自生矿物,二者之间界面平直。同时在火山岩示顶底构造发育部位杏仁体常具溶蚀特征。分析表明,火山岩中示顶底构造的特征及成因与渗流带的淋滤作用有关。示顶底构造发育部位杏仁体溶蚀孔的发育及气孔中未完全充填的剩余孔隙极大地改善了火山岩的储集性能。火山岩中示顶底构造的发现对火山岩岩层的顶底识别、火山岩岩相的划分及油气勘探具有重要的意义。     

预应力锚固技术在昆河线402滑坡治理工程中的应用

昆河线402+200～450m路段的地层是元古宇变质云母片岩,历次的构造运动及长久的风化作用,使该路段地表形成不稳定的堆积层滑坡体,虽然做过数次抗滑挡墙治理,但路基仍然发生多次滑坡。对滑坡成因进行综合分析,决定采用预应力锚索板框架工艺作为该项处滑坡治理方案。通过对预应力锚固设计与施工工艺的分析,说明该技术的应用在滑坡治理工程中的作用。工种治理中进行了如锚索抗拔试验、压浆柱质量检验和钢绞线极限强度试验等一系列测试,结果证明,该技术的各项技术指标均达到或大于设计要求,治理经验可供同类工程借鉴。     

气象电子显示屏在高危行业中的应用

为避免和减少因气象灾害引发的高危行业安全生产事故,围绕如何充分发挥气象信息在高危行业中的作用,进一步拓宽气象电子显示屏在高危行业的安装范围,突出特色气象服务项目,为高危行业提供更合适的气象产品,提高其减灾防灾的能力,充分发挥气象服务信息的作用。     

北祁连-河西走廊地区垂直形变与构造应力场关系的初步研究——三维有限元拟合结果分析

根据已知的地震地质资料对北祁连 -河西走廊及相邻区进行了三维有限单元剖分 ,在线弹性条件下 ,拟合了其 2 0a来垂直运动的总体趋势。计算表明 ,北祁连 -河西走廊地区垂直形变的拟合结果 ,与背景应力场的约束形式和变化特征密切相关 ,其中采用构造应力场增强作为加载条件以及稳定地块作为位移约束条件得出的拟合结果与该区域 2 0a来垂直运动的整体分布特点相一致。在此基础上 ,进一步得到其背景应力场增强的量值估算 ,其中SN方向的压力变化为 +0 .11MPa(压为正 ) ,EW方向的压力变化为 +0 .0 4MPa(压为正 ) ,EW方向的压力变化量是SN方向的 3倍左右。此外 ,根据计算得到的 10～ 15km深处剪应力增量Δγxy的分布情况 ,对比中强地震震源分布可以看出 ,剪应力增量与震源在空间分布上有一定的关联性。震源往往分布在剪应力增量变化较剧烈处 ,从而证实了拟合得出的构造应力场具有一定的合理性     

Excel回归分析及其在矿井瓦斯涌出量预测中的应用

回归分析方法是处理变量之间相关关系的有利工具,在很多领域都有应用。介绍了多元线性回归分析的数学原理,以及用MicrosoftExcel工作表进行多元回归分析的多种方法。在应用实例中用常村矿井的钻孔实测数据,演示了Excel多元线性回归各种方法的分析过程。     

Sediment phosphorus fractions and profile distribution at different vegetation growth zones in a macrophyte dominated shallow Wuliangsuhai Lake,China

Sediment phosphorus (P) fractions and profile distribution at submerged macrophyte growth zone, emergent macrophyte growth zone and open-water zone were studied in Wuliangsuhai Lake, China, as well as the correlations among water content, grain size, and organic matter and P fractions. Among the three surveyed zones, the highest concentrations of most P forms occurred in the surface sediment and the lowest between a depth of 12 and 22 cm, except HCl-P and NaOH-P. Sediment phosphorus was mainly associated to inorganic forms (>50%) in three surveyed areas, and the highest value of inorganic phosphorus (IP) in the surface sediment was obtained from submerged macrophyte growth zone. Submerged and emergent macrophytes increased the IP content by 107 and 44 μg/g, respectively, in the surface sediment compared with open-water zone. Vertical profiles of IP in the three surveyed zones showed that the concentrations decreased from surface to 12 cm depth and then increased. There was a similar trend in the sediment profiles of organic phosphorus (OP) and total phosphorus (TP), but the highest concentration of OP and TP in surface sediment was obtained from the emergent macrophyte growth zone. Compared with open-water zone, the emergent macrophyte increased TP content in surface sediment by 1.73 times to 1,320 μg/g, while submerged macrophyte enhanced TP content in the surface sediment by 1.13 times to 865 μg/g. It was observed that in macrophyte growth zones, a strong linear correlation existed between organic matter and OP (r > 0.98), and the maximum concentrations of OP were present in the areas with maximum concentrations of organic matter. Results show that, although rooted macrophyte could uptake directly P from sediments, it is responsible for increasing the internal P loading especially OP by reducing current velocities, attenuating wave energy and generating organic residue in Wuliangsuhai Lake.     

Closed recirculating system for shrimp-mollusk polyculture

This paper deals with a new system of aquaculture, i.e., a closed recirculating system for shrimp-mollusk polyculture. The culture system consisted of several shrimp ponds, a mollusk water-purifying pond and a reservoir. During the production cycle, water circulated between the shrimp and mollusk ponds, and the reservoir compensated for water loss from seepage and evaporation. Constricted tagelus, Sinonovacula constricta, was selected as the cultured mollusk, and Pacific white shrimp, Litopenaeus vannamei, as the cultured shrimp. The main managing measures during the production cycle were： setting and using the aerators; introducing the probiotic products timely into the shrimp ponds; adopting a “pen-closing” method for controlling shrimp viral epidemics; setting the flow diversion barriers in the mollusk pond to keep the circulating water flowing through the pond along a sine-like curve and serve as substrate for biofilm; no direct feeding was necessary for the cultured mollusk until the co-cultured shrimp was harvested; natural foods in the water from the shrimp ponds was used for their foods. Two sets of the system were used in the experiment in 2002 and satisfactory results were achieved. The average yield of the shrimp was 11 943.5 kg/hm^2, and that of the mollusk was 16 965 kg/hm^2. After converting the mollusk yield into shrimp yield at their market price ratio, the food coefficient of the entire system averaged at as low as 0.81. The water quality in the ponds was maintained at a desirable level and no viral epidemics were discovered during the production cycle.     

Fluvial process of the Huanghe River estuary

Influence of the evolution of the Huanghe River estuary, especially that of four large avulsions in recent years 1953, 1960, 1964 and 1976 on the lower reach was discussed. From this some measures for solving the problem of sedimentation at river mouth were proposed. This paper was published in Chinese inOceanologia et Limnologia Sinica 13 (3): 218–224, 1982. The main ideas of the first three parts of this article were included in the report delivered at the International Symposium on River Sedimentation held in Beijing, March 24–29, 1980.     

天然气水合物专题研讨会简介

报道了天然气水合物专题研讨会的概况，介绍了天然气水合物及其地理化学特征，并就开发天然气水合物对分析测试技术的要求做了简单介绍。