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261.
We evaluated ecological monitoring data and landowner perceptions to the federally funded Wetlands Reserve Program (WRP) in a three-county region in Wisconsin. We surveyed landowner satisfaction, involvement, participation, and use of the WRP restoration sites. We found that landowners are satisfied with the overall program (mean, 3.6 ± 0.2 [SE], on a scale of 1–5, with 5 being completely satisfied). WRP restorations significantly increased the area of wetland within the sites surveyed, the increase was primarily of fresh meadow (736.32 ha after restoration). Satisfaction is related to landowner participation during restoration and to the economic incentives provided by the WRP, Landowner satisfaction and the number of plant communities after restoration are unrelated to each other or to restoration and easement costs per hectare. Survey participants recommended some changes to the WRP, including a reduction in the tax rate of land enrolled in the WRP, approval for permanent deer stands, and increased communication with WRP officials during the restoration. Monitoring information collected for WRP restoration sites does not allow assessment of whether WRP sites are functionally equivalent to natural sites. We suggest that the WRP require a more rigorous monitoring program, including guidelines for invasive species control. Managers should also encourage collaborations with external researchers and consider restorations within an experimental framework. 相似文献
262.
综采工作面粉尘浓度分布的数值解法 总被引:2,自引:0,他引:2
分析工作面流场和粉尘分布的特点,采用气──固两相流原理,导出描述综采工作面粉尘分布的数学模型。用数值方法一有限容积法求解数学模型,编制了计算综采工作面三维空间内风速和粉尘浓度分布的计算机程序。 相似文献
263.
During 1970 the Geological Survey conducted a study to evaluate the surface-water data collection program. Objectives were formulated, specific goals were set, a massive analysis of available data was made to determine the extent to which the present system enables the goals to be met, alternatives were considered for meeting the remaining goals, and finally, specific elements were identified for inclusion in the future program. The results of the evaluation will be used in planning the future streamflow data program. Less productive elements in the present program can be weeded out, and the effort devoted to more critically needed water data. The study provides the groundwork for redirection of efforts towards a more efficient system for satisfying present and future needs. 相似文献
264.
阐述了跨界流域监测方案对于科学指导实践的重要性,提出方案具有针对性、完整性、规范性和可行性等基本特征。结合总体设计思路和要点,从组织机构、技术要求、质量控制等3个方面论证了方案的构成,针对当前编制并实施跨界流域监测方案中存在的针对性不强、缺项和漏项多、前期工作不到位、认识不统一等问题,提出了加强前期调研、技术培训和全程监督等应对措施,要建设先进环境监测预警体系新要求,通过加快技术创新,建立新型环境监测技术路线。 相似文献
265.
Lihua ZHANG Zhiliang ZHU Yanling QIU Ronghua ZHANG Jianfu ZHAO 《Frontiers of Environmental Science & Engineering in China》2008,2(4):505-508
The dissociation constants of polyepoxysuccinic acid (PESA) were investigated in this study. Based on the potentiometric titration
and the BEST program, the dissociation constants of PESA were determined. Considering the complexity of the dissociation of
PESA in aqueous solution, several models were constructed to simulate the dissociation process of PESA. By comparison, the
dissociation constants of PESA were obtained with model 4. The species distribution of PESA in aqueous solution as a function
of pH was also presented according to the experimental and calculation results. It showed that the H2L model with five basic structure units to describe the dissociation of PESA was reasonable, and the relevant constants had
less error and better matching between the experimental and calculation data. The corresponding values of pK
ai were 4.68 and 4.92, respectively, for H2L at 35°C with ionic strength of 0.1 mol/L. 相似文献
266.
新疆鄯善县吐峪沟千佛洞崩塌灾害特征及防治对策探讨 总被引:1,自引:0,他引:1
为了查清新疆鄯善县吐峪沟千佛洞旅游区崩塌灾害的危害,对区内崩塌灾害的分布、发育特征、形成影响因素及破坏模式等进行了详细勘查,结果表明崩塌灾害主要受地形地貌、地层岩性、地质构造、风化、降水、地震、人类工程活动等多种内外因素的影响,崩塌危岩体直接威胁旅游区内人行栈道和部分佛窟;同时针对勘查结果,提出了避让与治理相结合的防治... 相似文献
267.
268.
不同剖面层次土壤磷素运移研究 总被引:2,自引:0,他引:2
以陕西杨凌地区塿土为研究对象,通过饱和稳定流土柱运移试验,测定磷酸盐(H_2PO_4~-)在不同层次土壤中的运移穿透曲线(BTC),应用CDE模型、CXTFIT软件程序对其实测穿透曲线(BTC)进行拟合求其运移参数,研究其运移规律。结果表明,磷酸盐在塿土中的运移受到土壤的强烈阻滞作用,随着CaCO_3含量增加,磷酸盐运移所受的阻滞作用增大。磷酸盐在塿土不同剖面层次中运移所受阻滞作用大小与CaCO_3含量呈极显著的正相关,r=0.9791;而与粘粒含量且成极显著的负相关、r=0.9318。磷酸盐在塿土不同土层运移所受阻滞作用大小顺序为:钙积层>堆垫表层>粘化层,其阻滞因子R值分别为:11.80~13.00,5.20~7.00,3.90~5.00。 相似文献
269.
In this study, a dual-interval fixed-mix stochastic programming (DFSP) method is developed for planning water resources management systems under uncertainty. DFSP incorporates interval-parameter programming (IPP) and fuzzy vertex analysis (FVA) within a fixed-mix stochastic programming (FSP) framework to address uncertain parameters described as probability distributions and dual intervals. It can also be used for analyzing various policy scenarios that are associated with different levels of economic consequences since penalties are exercised with recourse actions against any infeasibility. A real case for water resources management planning of Zhangweinan River Basin in China is then conducted for demonstrating the applicability of the developed DFSP method. Solutions in association with α-cut levels are generated by solving a set of deterministic submodels, which are useful for generating a range of decision alternatives under compound uncertainties. The results can help to identify desired water-allocation schemes for local sustainable development that the prerequisite water demand can be guaranteed when the available water resource is scarce. 相似文献
270.
夏成明 《防灾减灾工程学报》2000,(3)
根据安徽省地震局规定使用的表面震源《走时表》 ,按其精度要求 ,把震中距分成三个距离段进行程序设计。在数据处理上 ,对 4 6°以内的数据 ,为保证精度 (0误差 ) ,采用数据检索方式 ;而对 4 6°~ 13 5°之间的数据 ,在保证精度的前提下 ,先进行线性拟合 ,解出一系列关于Δ的函数方程 ,再进行程序编制 ,在实际使用中发挥了较好的作用。 相似文献