Local‐scale Benefits of River Connectivity Restoration Planning Beyond Jurisdictional Boundaries

Conservation planning aims to optimize outcomes for select species or ecosystems by directing resources toward high‐return sites. The possibility that local benefits might be increased by directing resources beyond the focal area is rarely considered. We present a case study of restoring river connectivity for migratory fish of the Great Lakes Basin by removing dams and road crossings within municipal jurisdictions versus their broader watersheds. We found that greater river connectivity could often be achieved by considering both intra‐jurisdictional and extra‐jurisdictional barriers. Focusing on jurisdictional barriers alone generally forfeited <20% (median = 0%) of habitat gains for those who value solely habitat gains within the jurisdiction, but >75% (median = 100%) for planners who value larger‐scale habitat gains. Similarly, cost savings tended to be between ?50% and +50%, but in some cases were very negative. Our study underscores the local‐scale benefits of broadening restoration investments, especially for decision makers of the Great Lakes Basin and contributes to a discussion of appropriate and efficient scales of conservation planning. Copyright © 2017 John Wiley & Sons, Ltd.     

青海省公路桥涵水文分区方法与指标研究

介绍了青海省公路桥涵水文分区的现状,通过分析河流的水情变化,论证了修正现行水文分区的必要性,并结合青海省河流的特殊性,对比了省内外一些典型的水文区划方法及水文因子。结果表明:①应根据流域水系、内外流区、沙漠面积等定性指标,以原水文分区为一级区划,在其基础上进行修正并确定二级分区;②利用河川径流强度指标法进行分区划分时,分区指标为年平均降水量、岩土类型、河网密度和沟谷比重;③利用模糊聚类法进行分区划分时,分区指标为年平均径流深、年平均降水量、气候带、河流补给形式及单位面积上50 a一遇设计流量,但只有黄河上游区、湟水大通河区可使用该方法;④青海省内沙漠面积较大,在分区时可将其划分为非产流区。     

中小型水库坝下排水涵管除险加固设计要点

我国20世纪50~70年代修建的中小型水库,其泄水建筑物大多采用坝下涵管,因受当时技术条件的限制,且年久失修,致使大多数涵管存在渗漏或其他问题,严重影响到大坝的安全运行。根据多年处理中小型病险水库的经验,对防止涵管接触渗漏的设计要点、防止内水外渗的设计要点、原涵管拆除与兴建的设计要点、原涵管封堵与新建虹吸管的设计要点等进行了归纳总结。其设计经验对中小型病险水库的除险加固有重要参考价值。     

深季节冻土区涵洞热状况分析

为分析深季节冻土区涵洞对路基及其下地基热状况的影响,建立了涵洞温度场计算模型,基于已有的试验涵洞监测数据,对比分析了所建模型的可靠性,再在该模型基础上,通过改变材料参数和模型尺寸,进行不同情况下的数值计算。结果表明：模拟季节冻土区涵洞温度场时,需要充分考虑热对流效果,忽略填土热对流效果是不合适的,考虑热对流效果的模型在定性和定量上均与现场监测情况一致;在季节性冻土区涵洞设计工作中,应该采取一些积极措施避免或减少对流传热对涵底冻深发展的影响;涵底最大冻结深度随着含水量呈三段式的变化规律：随其增大先减小,后减小速度变缓甚至冻深略有增加,最后又趋于减小;寒区涵洞内径的尺寸对涵底冻结深度方面的影响较大,而净高对涵底冻结深度方面的影响很小,可以不考虑。     

Three‐dimensional numerical simulations of smooth,asymmetrically roughened,and baffled culverts for upstream passage of small‐bodied fish

Traditional box culvert designs lead to development of high velocity zones in the culvert barrel that often impede upstream migration of fish. Herein, three‐dimensional Reynolds‐averaged Navier‐Stokes (RANS)‐ and Large eddy simulation (LES)‐based computational fluid dynamics (CFDs) simulations were performed to compare the effectiveness of smooth, asymmetrically roughened, and corner‐baffled barrels, in creating low‐velocity zones (LVZs) and providing opportunity for upstream passage of small‐bodied fish. The results revealed distinctive benefits provided by the asymmetrically roughened and corner‐baffled barrels relative to the smooth barrel. Cross‐sectional asymmetry, corners, and obstructions are important factors that contribute to the generation of LVZs conducive to fish passage, albeit contiguity of LVZs is required, particularly for weak swimmers. The study demonstrates the adequacy and effectiveness of CFD models to complement traditional laboratory studies in understanding basic mechanisms beneficial to fish passage and to provide insights into future designs.     

隐蔽工程建设中的"三新"

长江重要堤防隐蔽工程在建设过程中,注意推广应用新技术,新工艺,新材料,并在应用中不断改进提高,还根据工程建设的需求开发新技术,解决工程实际问题,“三新”的应用不仅提升了堤防建设的科技含理,更重要是保证了隐蔽工程建设的质量和工期。     

Ausbau des Stichkanals nach Salzgitter von SKS‐km 3,550 bis 14,918

Expansion of the branch channel to Salzgitter from SKS‐km 3,550 to 14,918 The branch channel to Salzgitter will be extended to the waterway category Vb in the next years. This will enable inland waterway vessels with a width of 11,45 m and a loaded draft of 2,80 m to run it without limitations. The reaches Wedtlenstedt and Üfingen will be extended in most areas to a trapezoidal cross section with a width at water level of 36,90 m and a water depth of 4,00 m. The exit basins of the locks will be extended on one side. Overall about 1 000 000 m² of soil will be moved. About 300 000 m² of clay sealing and 460 000 m² of rip‐rap will be installed. Three culverts have to be replaced by new constructions to adapt to the new cross section of the channel. In addition two bridges will be modified to allow for a clearance of 5,25 m. At present the plan approval procedure is carried out. It is expected to achieve the plan approval order in 2017. The construction is planned to start in 2018. Completion is scheduled for 2024.     

输水管道内壁卫生防腐技术

某供水改造工程使用的是大直径有压涵管。管内径为4.8 m,采用高性能C40、W10混凝土。引用的原水为江水,含有大量微生物、原幼虫和细菌等。为防止污染水质,在管道内壁喷涂卫生型防护涂料。     

Three-dimensional modeling of soil-steel culverts under the effect of truckloads

Soil-steel culverts have been successfully used as a cheap alternative to the conventional steel or reinforced/pre-stressed concrete bridges. Current design codes and researchers usually approximate the effect of live loads on such soil-steel culverts. In this study, three-dimensional (3D) finite element (FE) analyses of two existing soil-steel culverts are performed and compared to the published theoretical and experimental results. The study shows that the results of the 3D FE analyses for the thrusts compare well with the experimentally measured ones with differences less than 30%. On the other hand, the FE results for bending moments show less agreement which may be due to the sensitivity of the bending moments to the accurate modeling of the properties of the soil material. The study also shows that the effect of the live loads extends for a very limited longitudinal length of the examined corrugated steel culverts and validates the use long prismatic longitudinal geometry in performing their 3D FE analysis.