飞来峡水利枢纽对北江河流综合影响研究

综合分析飞来峡水利枢纽平面布置、运行管理等方面,对北江河流水流流态、河道变化、水质、水温、水生物等方面的影响。枢纽建设运行有不利的影响因素,对河流生态方面的影响提出改进的建议。     

模糊数学评价法在棋盘山水库水环境评价中的应用

为了综合评价棋盘山水库水环境质量,测试了棋盘山水库的高锰酸盐指数、化学需氧量、五日生化需氧量、氨氮、铜、总锌、铅、镉、氰化物、阴离子表面活性剂、硫化物等19项评价因子的浓度并对照地表水质量评价标准[1]进行了各个测试项目的水质级别分类,大部分检测项目均为Ⅰ类,只有氨氮和总磷为Ⅲ类水,直观上分析完全满足鱼虾等水生动物生存以及水产养殖。最后应用模糊数学综合评价法评价了棋盘山水库水质质量综合评价等级为Ⅰ类。     

叶尔羌河库鲁克栏杆站-喀群站洪水传播时间规律

通过建立库鲁克栏杆站和喀群站流量与单位河长传播时间Q―t关系,确定了库鲁克栏干站-喀群站河段流量与洪水传播时间关系的基本模式。根据2站历史洪水数据建立的Q―T0关系验证了库鲁克栏干站-喀群站河段流量与洪水传播时间基本模式。库鲁克栏杆站洪水流量超过2 000m3/s,库鲁克栏干站-喀群站河段洪水传播时间稳定在7-8h。     

探地雷达在冬季冰下水深探测中的应用研究

本文从理论上分析了探地雷达用于冰下水深探测的基本原理。介绍了采用该项技术对辽河福德店段的探测过程。通过对采集数据处理和图像解释分析,得到河道断面连续水深值,并进行钻取冰眼测量验证,证明探测结果是可靠的。     

不同地下水水质评价方法的比较及实例应用

为真实准确地反映地下水水质情况,分别介绍了F值法、内梅罗指数法、模糊综合评价法的基本原理,以2013年北京市某地区地下水枯水期6例水样为例,进行评价分析。结果表明：F值法使用便捷,结果直观,应用广泛,但会造成一定的不连续性,缺失Ⅲ类水。内梅罗指数法运算简洁,但过于突出最大污染因子,并且没有准确的地下水质量类别划分依据。模糊综合评价法虽然计算过程复杂,但是计算结果更加准确。经过3种方法的分析比较可以为实际工程中地下水评价方法的合理选择提供一定的技术指导。     

EVALUATION OF SPAWNING SUBSTRATE ENHANCEMENT FOR WHITE STURGEON IN A REGULATED RIVER: EFFECTS ON LARVAL RETENTION AND DISPERSAL

Site‐specific habitat alterations have improved spawning success and early life stage survival of different fish species, including sturgeon, in regulated rivers. We modified the substrate within a section of river at the only known spawning site used by white sturgeon (Acipenser transmontanus) in the Mid Columbia River, Canada. Existing armoured riverbed conditions were modified using a mixture of larger and smaller angular rock with the assumption that the larger material would remain in place at higher discharges and help retain the smaller material. This increased substrate complexity and the amount of available interstitial spaces. We stocked 2‐day posthatch larvae over both the modified site and at an adjacent control site that represented existing substrate conditions. Our objectives were to determine (i) the extent that stocked larvae remained in both the modified and control sites immediately after release, (ii) the timing of subsequent dispersal of larvae from both sites and (iii) how total length of dispersing larvae changed over time and by site. Results from this work indicated that the modified section of riverbed retained significantly higher numbers of larvae after release compared with the control site. Larvae at the modified site were able to hide and remain within the substrate and initiated downstream drift 15 days after release. With the exception of the first day after release, dispersal from both sites occurred at night. There was a significant effect of time after release and site on the total length of dispersing larvae. The larger variation in total larval length observed at the control site compared with the modified site indicated greater difficulty in hiding within the control substrate. Larvae initiated dispersal from the modified site at a mean size of 17.5 mm, which may indicate an important growth threshold before drift. Results from this work are important for future mitigative efforts for sturgeon in regulated rivers where changes to spawning substrates have occurred. Copyright © 2012 John Wiley & Sons, Ltd.     

EVALUATION OF THE SOUNDING ROD METHOD FOR SAMPLING COARSE RIVERBED SEDIMENTS IN NON‐WADEABLE STREAMS AND RIVERS

The substrate of fluvial systems is regularly characterized as part of a larger physical habitat assessment. These measures are instrumental in meeting the regulatory responsibilities of bioassessment and monitoring programs, and essential to monitoring restoration and rehabilitation success. We describe and validate a commonly used technique for broadly categorizing, and thus characterizing, the substrate in non‐wadeable streams and rivers called the sounding rod method. In brief, a rod, often hollow, is used to probe the substrate of non‐wadeable systems to characterize the substrate. We tested the viability of this method on three different systems by comparing estimated particle class and direct particle measurements. Our results indicate that substrates can adequately be defined into six broad classes (fine‐particle sediment, sand, gravel, cobble, boulder and bedrock) based on size using the sounding rod. Estimated classes were significantly positively correlated to measured classes (τ = 0.83, p < 0.001), and estimates of size class and direct measurements of size were not from significantly different distributions (χ² _0.05,9 = 569.51, p < 0.001). Further, there were significant differences between each category (H = 243.5, 3 d.f., p < 0.001). Although our results affirm that actual substrate class size can be directly inferred from estimated data, it should be noted that soft sediments <200 mm were not always detected. This finding should be carefully considered with individual study objective. Overall, the sounding rod method can be learned quickly, and it is a low‐cost and time‐efficient method for substrate classification. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.     

ASSESSMENT OF CONSEQUENCES OF SEDIMENT DEFICIT ON A GRAVEL RIVER BED DOWNSTREAM OF DAMS IN RESTORATION PERSPECTIVES: APPLICATION OF A MULTICRITERIA,HIERARCHICAL AND SPATIALLY EXPLICIT DIAGNOSIS

As regards river restoration, it is fundamental to better link human pressures and environmental responses and to take into consideration not only target species or habitat but diverse ecological elements. This permits to assess sustainable restoration plan, especially concerning sediment augmentation below dams. The use of a hierarchical multicriteria approach on the Ain River permits us to assess a diagnosis of sediment deficit impact integrating several morphological (channel shifting, river bed degradation and river bed coarsening) and ecological components (Riparian and floodplain lake and fish communities). Our diagnosis also integrates a temporal and spatial approach better to link human pressures and environmental responses and to identify the dam effects amongst other drivers (e.g. grazing decline and channel regulation). The results confirm causality links between sediment deficit and slight channel bed degradation (0.01 m.year^?1) or channel bed paving and thus highlight the impact of the dam on the drying of the riparian forest and on former channel community. However, the relationship between incision and reduction in active channel lateral mobility is more difficult to establish. The role of sediment deficit in the current variability of the riparian regeneration capacity and, thereby, landscape diversity along the lower valley remains unclear. This study also confirms the relevance of using different ecological indicators, notably because all components present different adjustment time scales, whereas some of them are more sensitive to other impacts. Copyright © 2013 John Wiley & Sons, Ltd.     

IMPACT OF CHANGING HYDROLOGY ON NUTRIENT UPTAKE IN HIGH ARCTIC RIVERS

Despite the importance of river nutrient retention in regulating downstream water quality and the potential alterations to nutrient fluxes associated with climate‐induced changes in Arctic hydrology, current understanding of nutrient cycling in Arctic river systems is limited. This study adopted an experimental approach to quantify conceptual water source contributions (meltwater, groundwater), environmental conditions and uptake of NO₃^?, NH₄⁺, PO₄^3? and acetate at 12 headwater rivers in Svalbard and so determine the role of changing hydrology on nutrient uptake in these Arctic river systems. Most rivers exhibited low demand for NO₃^? and PO₄^3?, but demand for NH₄⁺ and acetate was more variable and in several rivers comparable with that measured in sub‐Arctic regions. The proportion of meltwater contributing to river flow was not significantly related to nutrient uptake. However, NH₄⁺ uptake was associated positively with algal biomass, water temperature and transient storage area, whereas acetate uptake was associated positively with more stable river channels. Mean demand for NH₄⁺ increased when added with acetate, suggesting NH₄⁺ retention may be facilitated by labile dissolved organic carbon availability in these rivers. Consequently, nutrient export from Arctic river systems could be influenced in future by changes in hydrological and environmental process interactions associated with forecasted climate warming. Copyright © 2013 John Wiley & Sons, Ltd.     

EFFECT OF A MAJOR FLOOD ON BREEDING AND HABITAT OF THE CRIMSON FINCH (NEOCHMIA PHAETON): A RIPARIAN SPECIALIST

Riparian specialists, such as the Crimson Finch (Estrildidae: Neochmia phaeton), are vulnerable to declines in habitat quality, including alterations of flow regime associated with dam construction. Crimson Finches persisted and bred in substantial numbers following two large floods in the Isaac–Connors catchment in early 2008. Major flooding was not detrimental to nesting and breeding success, although the immediate post‐flood period was identified as a bottleneck in the availability of riparian grass seed. Crimson Finches nested at 16 m or more above the normal river level (compared with an average of 2–3 m elsewhere in Northern Australia); indicating that they have adapted to the extreme flood peaks in the Fitzroy River basin. The tall river‐associated grass Chionachne cyathopoda was a key habitat plant, retaining seed well into the dry season when most other grasses are expended. It also provided abundant seeds following floods, coinciding with peaks in abundance of dependent young finches. The adaptations of both Crimson Finches and Chionachne suggest that increased flooding, predicted by climate change, is unlikely to be a problem. In contrast, a proposed dam on the Connors River may be a threat. River regulation that reduces peaks of major floods may favour introduced riparian grasses over flood adapted native grasses such as Chionachne. Any change in the quantity of this species could be detrimental to persistence of Crimson Finches. Environmental managers should carefully consider the ecology of Chionachne when making decisions about river flows. Copyright © 2013 John Wiley & Sons, Ltd.