共查询到20条相似文献，搜索用时 78 毫秒
1.
七里海潟湖湿地位于河北昌黎黄金海岸国家级自然保护区内,是国内外仅存的现代潟湖之一,在沿海湿地类型中具有较强的典型性和代表性,具有重要的生态功益和保护价值。但是在其演变过程中,由于受到自然环境条件和人类违背自然规律活动的影响,七里海出现了严重的退化现象。如何恢复治理和保护七里海资源是一个亟待解决的问题。本文根据七里海退化状况,系统分析了退化原因,并提出有针对性的修复对策。 相似文献
2.
3.
4.
本文对七里海湿地气候、水文、土壤及生物进行了论述;利用遥感解译技术提取湿地信息,总结了七里海二十来年自然生态变化特征;根据水资源平衡原理进行了生态需水量保障分析;提出了水资源修复建议。 相似文献
5.
长江流域生态环境修复是中国近年来生态环境保护工作的重要组成部分,文章基于长江流域（江苏境内）废弃露天矿山现状特征以及大量矿山生态修复工作经验,提出了生态工程模式、土地整治模式、景观再造模式及自然恢复模式,并对这四种模式的特点及适用性进行了阐述,结果可以为废弃矿山生态修复提供借鉴。以江苏省长江沿岸某废弃露天矿山生态修复工程为例,通过生态环境问题分析,明确该废弃露天矿山在地质灾害隐患发育、生态环境及地貌景观破坏以及土地资源浪费等方面存在的主要问题,最终成功采用生态工程模式开展该废弃矿山的生态修复工作,产生了良好的生态效益、社会效益和经济效益。 相似文献
6.
7.
《中国煤炭地质》2021,(8)
祁连山是我国西北重要的生态屏障,以往露天煤矿的破坏性开采导致生态环境问题突出。为系统修复祁连山南麓露天煤矿开采引发的生态环境问题,选取木里煤田聚乎更矿区为研究区。通过无人机遥感解译、现场调查、工程地质测绘等技术手段,从水文地质、工程地质、环境地质角度提出研究区生态环境问题主要为地貌生态景观及地表草甸冻土破坏、采坑及渣山边坡失稳和采坑积水等;提出矿山生态修复治理应综合考虑工程地质、环境地质、水文地质理论知识结合生态学知识,即整治矿区内边坡失稳的同时考虑地表及地下水的联通与保护,对矿山植被修复采取以自然恢复为主,人为干预为辅的原则。考虑到不同露天矿井的差异性,提出应针对不同矿坑采用"四工程一保障"开展生态修复工作。"四工程"即"采坑整治、边坡与渣山治理、水系修复、植被复绿"四项工程措施;"一保障"指矿区生态环境监测信息系统。 相似文献
8.
9.
10.
煤炭开采引起的地表沉陷造成的地质灾害、经济损失和社会问题日趋严重,对采煤沉陷区进行生态环境修复治理尤为迫切。本文以贵州安龙县普坪采煤沉陷区为研究区域,基于该采煤沉陷区矿山地质环境调查成果,针对存在的地质环境问题提出生态环境修复措施。结果认为：安龙县普坪采煤沉陷区地质环境问题主要为矿山地质灾害、地下水资源破坏和土地资源损毁。生态环境修复治理中应有针对性地采取搬迁工程措施、工业场地及废弃建筑物拆除措施、矿区残余房屋拆除措施、煤矸石堆修复工程措施、土地整治的工程措施及复绿工程措施。通过实施生态修复措施将有效改善矿区生态环境,减少和控制地质灾害发生,实现良好的环境、经济及社会效益。 相似文献
11.
杭州西湖疏浚底泥工程性质试验研究 总被引：5，自引：0，他引：5
针对西湖疏浚底泥的沉积规律、颗粒分布、渗透特性、压缩特性等工程性质进行了室内试验,并分别对室内沉积土样和库区沉积土样的工程性质做了比较,得到了渗透系数、压缩系数等指标沿深度和距离上的变化规律。试验结果对进一步了解疏浚底泥的工程特性具有参考意义,也有利于指导蓄泥库疏浚底泥的后期处理措施的制定。 相似文献
12.
Omran Frihy Wahid Moufaddal Essam Deabes Essam El Din Helmy 《Arabian Journal of Geosciences》2016,9(14):637
The present study is the first attempt in Egypt to assess feasibility of using of dredging material from Damietta Harbor in the northwestern Nile Delta for erosion control. The study also provides an economic evaluation for the shoreline management alternatives selected to mitigate for the effects of coastal erosion at two pilot eroding areas (namely, A and B) located near the Damietta Harbor. Results of compatibility analysis reveal that the dredging material is fairly compatible with the native sand of the nearby eroding beaches. In addition to soft nourishment by dredged sand, other types of coastal engineering measures which are often used in erosion management area were also evaluated as alternatives for erosion control and mitigation solution. Economic feasibility assessment by means of cost-benefit analysis of direct and indirect items has been carried out to facilitate comparison between these alternatives. Analysis of alternatives has been also supported by other criteria to select the cost-effective and environmentally acceptable option to protect the eroding pilot areas. These criteria include the high total cost paid for maintenance of the Damietta Harbor channel with no use, anticipated impacts on the littoral system, sustainability, future plans for protection of the existing coastlines, and lessons learned from previous shore protection works in the Nile Delta. The final selection of the best viable alternative indicates that the procedure of beach nourishment is the most appropriate form for protection area A, while a combination of groins and sand nourishment is more relevant for area B. In any case, material dredged from the navigation approach of the Damietta Harbor should be utilized as a borrow material in the nourishment schemes and excluding use of the terrestrial sources. 相似文献
13.
Donna Marie Bilkovic 《Estuaries and Coasts》2011,34(1):129-147
To investigate the effects of dredging and associated development pressures (i.e., shoreline armoring, developed land use)
on fish, three sets of paired dredged and undredged tidal creeks were surveyed within Lynnhaven River, Virginia. Fish species
diversity, community abundance, biomass, and size structure were compared among creeks and related to watershed, shoreline,
and physicochemical characteristics. Mean fish community characteristics (e.g., abundance) were similar among creeks; however,
species-specific analysis revealed subtle differences. Species biomass differed between dredged and undredged creeks, though
species abundance was similar. Turbidity highly influenced differences in species abundance among creeks, while organic matter,
dissolved oxygen, turbidity, and shoreline hardening may be influencing biomass patterns. The most recently dredged creek
appeared to provide less suitable nursery habitat for some species than historically dredged creeks, suggesting initial adverse
effects with eventual recovery. Protective measures, such as preservation of marshes, dredge depth, and time-of-year restrictions,
may be moderating development and dredging pressures. 相似文献
14.
《China Geology》2018,1(4):512-521
Shandong has more than 70% of natural coasts are under erosion. Coastal erosion started from the 1970’s and became a very serious problem at 1990’s. The dramatic decrease of sediment supplies from rivers caused rapid erosion at the delta and estuary areas, especially in the abandoned Yellow River Delta. Most sandy coasts along the Peninsula were eroded due to lack of sand supply and interruption of alongshore sediment drift, sand dredging from the beach or the offshore area caused serious erosion during short time. Sea-level rise causes slow but constant shoreline retreats and became a more serious threat. Different types of hard solutions for coastal protection against erosion were used in Shandong. Seawalls are most widely used, especially at the Yellow River Delta and city center waterfront. Groynes, jetties and breakwater are used on the north and east sandy coast of the Peninsula. Hard approaches are effective to protect the coast erosion but not change the erosion causes and led secondary impact on the coast. Soft engineering solution or the combined solutions are taken into acts. Beach nourishment is mostly considered as the better soft solution, especially to those tourists attracting sandy beaches along the Shandong coast. Long term monitoring and continuous lessons learning from the coastal erosion management will be adaptive for better coast solution in the future. 相似文献
15.
Detrimental effects of engineering works on the coast and a wish to conserve parts of the coastline have increased realization among coastal managers of the need to examine shoreline problems and proposals for protection in a wider spatial context than the site itself and over a longer time scale than the past few years. This paper outlines the approach taken in one region of the United Kingdom, the central south coast of England, to provide that wider perspective. Authorities responsible for coastal protection and sea defenses formed a coastal group, which, among other activities, commissioned research aimed at providing a greater understanding on which to base shoreline management decisions. A major project undertaken was a sediment transport study in which all existing information relating to coastal sediment processes in the region was collated and analyzed. All inputs, flows, and outputs of sediment were documented. Links between processes were examined for each part of the region. Finally, nine littoral cells of sediment circulation were identified and were suggested as forming a framework for shoreline management. The methods of compilation and analysis are outlined here and are exemplified for one area in the region. The approach is recommended as a cost-effective basis for strategic management of the coast in developed regions. 相似文献
16.
Tapas K. Mallik 《Environmental Geology》1985,7(3):151-157
Detailed survey on various aspects has indicated the presence of calcareous sands in the lagoons of Lakshadweep (Arabian Sea)
suitable for a number of industries. No data are available about the effect of mining the deposits on these atolls. This paper
attempts to analyze the data collected in studying the channel that has been dredged in connection with development of the
harbor at Kavaratti lagoon Maximum depth in the lagoon is 3 m Outside the depth increases rapidly within a short distance
of about 100 m Sediment in the lagoon is derived from the destruction of the reefs and consists of corals, halimeda, molluscan
shells, foraminifers, and red algae Presently sands are being dredged from the lagoon and dumped in the sea and these sands
are lost as there is a steep slope outside A study of shoreline records for the beaches adjacent to the dredging site shows
that the shoreline is an area of accretion. It is quite possible that removal of 1 or 2 meters of sands from the lagoon floor
will not affect the equilibrium if the reef is not disturbed Dredging of coral sands for different purposes is known from
Fiji, Johnson Island, offshore Apia and no adverse effect has been noticed Removal of limited quantity of sands is recommended,
since in a closed system of such atolls like Kavaratti there is always a surplus of sediment transported to the deep sea.
The surplus sediment opens the way to sediment dredging. However, reef areas should not be disturbed since the reef is the
most important sediment-generating site Studies on growth rate, currents, tides, and bathymetry should be continued to detect
the adverse effect simultaneously with dredging
The views expressed in this paper are entirely those of the author and no organization is responsible for them. 相似文献
17.
河道疏浚拓宽以及港口新建扩建等不可避免地产生大量疏浚淤泥,如何处置大量废弃淤泥是工程界关注的一个重要研究课题。固化方法是目前处理疏浚淤泥的常用方法,其目的是将废弃淤泥处理成土工材料加以利用。处理后的淤泥固化土作为工程建设用土必须考虑其工程力学性能。为了研究疏浚淤泥固化土的压缩性状与结构屈服应力,进行了多组不同配比下淤泥固化土的压缩试验。通过室内一维压缩试验,研究了高含水率疏浚淤泥固化土的压缩性状,探讨了固化材料掺量、初始含水率、龄期等对固化土压缩变形特性和结构屈服应力的影响。压缩试验结果表明:与许多天然沉积结构性土及水泥土类似,疏浚淤泥固化土的压缩曲线均存在一个明显的结构屈服点。当上部荷载小于结构屈服应力之前,固化土的压缩性很小; 一旦上部荷载超过结构屈服应力之后,固化土的压缩性急剧增大。分析了淤泥固化土结构屈服应力的影响因素,并将由一维压缩试验得到的结构屈服应力(Py)与由无侧限抗压试验确定的抗压强度(qu)进行了比较,给出了两者之间的定量关系。疏浚淤泥固化土在屈服前后的压缩性状差异很大,这一研究成果对工程应用很有指导意义,当上部荷载较低时,可以充分利用其屈服前的低压缩性,但应确保上部荷载不能超出其结构屈服应力,以避免固化土在缺乏预兆的情况下发生突然破坏。 相似文献
18.
Piles and diaphragm wall-supported berthing structure on marine soils are loaded laterally from horizontal soil movements
generated by dredging. The literature on the adequacy of the finite element method modeling of berthing structure to analyze
their behavior during dredging is limited. This paper describes a finite element approach for analyzing the lateral response
of pile and diaphragm wall during dredging. Piles are represented by equivalent sheet-pile walls and a plane strain analysis
using the finite element method is performed. Results from the finite element method are compared with full-scale field test
data. Full-scale field test was conducted on a bearing structure to measure the lateral deflection on pile and diaphragm wall
for their full length using inclinometer during dredging in sequence. The finite element method results are in good agreement
with full-scale field results. Conclusions are drawn regarding application of the analytical method to study the effect of
dredging on piles and diaphragm wall-supported berthing structures. 相似文献
19.
为研究水下清淤人工冻结板温度场的发展规律以及冻土帷幕形成的过程,通过有限元分析软件,采用单因素分析法进行数值分析,研究了水下人工冻结板在几何及物理环境变化条件下的冻结规律。结果表明:冻结板不同几何尺寸与清淤深度的相关性较弱,调整冻结板的几何尺寸仅能改变清淤面积;对清淤环境来说,土层的导热系数越大,比热容越小,原始地温越低,其降温速度越快,清淤越高效;砂土的冻结效果要明显优于黏土;相变潜热对土体降温的影响十分有限;盐水降温计划中最低温度对清淤深度有较大影响,在-50℃以前,冻土帷幕发展较快,每降低10℃冻土帷幕的发展厚度增加约0.4 m,而在-50℃以后冻土帷幕的发展较慢,每降低10℃冻土帷幕厚度的发展仅约为0.05 m。因此,在工程实际中,冻结初期通过调节盐水降温计划可以较好的实现冻结效果;建议盐水降温计划最低温度设置为-50℃,此时可以得到的有效清淤深度约1.5 m。研究结果可为今后的相关实际工程提供参考依据。 相似文献
20.
寒区冻土环境与工程环境间的相互作用 总被引：24，自引：6，他引：18
从冻土环境和工程环境相互作用着手 ,分析了青藏公路建设过程中的冻土环境破坏、环境保护状况及冻土环境保护对工程建设的重要性 ,同时对正在拟建的青藏铁路 ,阐述了人类经济活动对冻土环境和工程环境的影响 ,并初步提出寒区冻土、工程环境质量监测、管理和评价系统的设计框架. 相似文献