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Reservoirs impose many negative impacts on riverine ecosystems. To balance human and ecosystem needs, we propose a reservoir operation method that combines reservoir operating rule curves with the regulated minimum water release policy to meet the environmental flow requirements of riverine ecosystems. Based on the relative positions of the reservoir and the water intakes, we consider three scenarios: water used for human needs (including industrial, domestic and agricultural) is directly withdrawn from (1) the reservoir; (2) both reservoirs and downstream river channels and (3) downstream river. The proposed method offers two advantages over traditional methods: First, it can be applied to finding the optimal reservoir operating rule curves with the consideration of environmental flow requirement, which is beneficial to the sustainable water uses. Second, it avoids a problem with traditional approaches, which prescribe the minimum environmental flow requirements as the regulated minimum environmental flow releases from reservoirs, implicitly giving lower priority to the riverine ecosystem. Our method instead determines the optimal regulated minimum releases of water to sustain environmental flows while more effectively balancing human and ecosystem needs. To demonstrate practical use of the model, we present a case study for operation of the Tanghe reservoir in China's Tang river basin for the three above‐mentioned scenarios. The results demonstrate that this approach will help the reservoir's managers satisfy both human and environmental requirements. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
153.
徐辰生 《水文地质工程地质》2001,28(4):73-75
邢台市区地下饮用水源位于太行山前储存两种相当丰富的岩溶水和孔隙水的百泉泉域径流排泄区。令人担忧的是:浅层孔隙水已受到轻度污染,深层岩溶水出现个别水井水质超标。本文针对几起地下饮用水源污染事例,探讨岩溶水饮用水源污染成因和规律。 相似文献
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A procedure for displacement‐based seismic design (DBD) of reinforced concrete buildings is described and applied to a 4‐storey test structure. The essential elements of the design procedure are: (a) proportioning of members for gravity loads; (b) estimation of peak inelastic member deformation demands in the so‐designed structure due to the design (‘life‐safety’) earthquake; (c) revision of reinforcement and final detailing of members to meet these inelastic deformation demands; (d) capacity design of members and joints in shear. Additional but non‐essential steps between (a) and (b) are: (i) proportioning of members for the ULS against lateral loads, such as wind or a serviceability (‘immediate occupancy’) earthquake; and (ii) capacity design of columns in flexure at joints. Inelastic deformation demands in step (b) are estimated from an elastic analysis using secant‐to‐yield member stiffnesses. Empirical expressions for the deformation capacity of RC elements are used for the final proportioning of elements to meet the inelastic deformation demands. The procedure is applied to one side of a 4‐storey test structure that includes a coupled wall and a two‐bay frame. The other side is designed and detailed according to Eurocode 8. Major differences result in the reinforcement of the two sides, with significant savings on the DBD‐side. Pre‐test calculations show no major difference in the seismic performance of the two sides of the test structure. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
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鄂西陡山沱组磷块岩矿层划分对比及成矿规律 总被引:5,自引:0,他引:5
鄂西陡山沱组磷块岩可以划分为三个工业矿层Ph_1,Ph_2,Ph_3和一个含磷层Ph_4,具有全区对比意义的有Ph_1,Ph_2和Ph_4。荆襄矿区工业矿层为Ph_1,Ph_2和Ph_3;宜昌和兴神矿区工业矿层为Ph_1和Ph_2,缺失Ph_3。各矿区磷矿层的分布随海侵方向由南向北出现明显而有规律地迁移,这一时空变化规律为恢复古地理及成矿预测提供了依据。 相似文献
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湘中白马山-龙山金矿带穹隆控矿规律分析 总被引:8,自引:0,他引:8
期望通过对湘中白马山-龙山金矿带的穹隆和发育于其核部的次级断裂与金(锑)矿成矿关系的深入研究来拓宽找矿思路.在野外调研的基础上,总结矿带上古台山、大乘山、龙山3个主要穹隆的地质特征及其对金(锑)矿的控制作用,认为穹隆为矿带的主要控矿构造,其核部的放射状断裂为容矿构造,并在此基础上建立了矿带的穹隆控矿模式.在金(锑)矿床勘查与找矿预测方面,提出应从穹隆的整体出发,重视对不同方向断裂的控矿性研究.通过对成矿带上不同穹隆剥蚀度的研究认为,大乘山穹隆为有利的找矿部位. 相似文献