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91.
山东半岛蓝色经济区海洋生态旅游发展研究 总被引:3,自引:0,他引:3
发展海洋生态旅游是实现山东半岛蓝色经济区战略的重要途径之一。在SWOT分析的基础上,指出在山东半岛蓝色经济区发展海洋生态旅游必须明确其动力机制,坚持统筹发展战略,从生态保护、社区参与、区域统筹和产业协同四个方面采取具体的对策。 相似文献
92.
Many lakes have experienced a transition from a clear into a turbid state without macrophyte growth due to eutrophication.
There are several measures by which nitrogen (N) and phosphorus (P) concentrations in the surface water can be reduced. We
used the shallow lake model PCLake to evaluate the effects of three measures (reducing external nutrient loading, increasing
relative marsh area, and increasing exchange rate between open water and marsh) on water quality improvement. Furthermore,
the contribution of different retention processes was calculated. Settling and burial contributed more to nutrient retention
than denitrification. The model runs for a typical shallow lake in The Netherlands showed that after increasing relative marsh
area to 50%, total phosphorous (TP) concentration in the surface water was lower than the Maximum Admissible Risk (MAR, a
Dutch government water quality standard) level, in contrast to total nitrogen (TN) concentration. The MAR levels could also
be achieved by reducing N and P load. However, reduction of nutrient concentrations to MAR levels did not result in a clear
lake state with submerged vegetation. Only a combination of a more drastic reduction of the present nutrient loading, in combination
with a relatively large marsh cover (approximately 50%) would lead to such a clear state. We therefore concluded that littoral
marsh areas can make a small but significant contribution to lake recovery. 相似文献
93.
Richard J. Horwitz Thomas E. Johnson Paul F. Overbeck T. Kevin O’Donnell W. Cully Hession Bernard W. Sweeney 《Journal of the American Water Resources Association》2008,44(3):724-741
Abstract: The joint influences of riparian vegetation and urbanization on fish assemblages were analyzed by depletion sampling in paired forested and nonforested reaches of 25 small streams along an urbanization gradient. Nonforested reaches were narrower than their forested counterparts, so densities based on surface area differ from linear densities (based on reach length). Linear densities (based on number or biomass of fish) of American eel, white sucker and tesselated darter, and the proportion of biomass of benthic invertivores were significantly higher in nonforested reaches, while linear densities of margined madtom and the number of pool species were significantly higher in forested reaches. Observed riparian effects may reflect differences in habitat and algal productivity between forested and nonforested reaches. These results suggest that relatively small‐scale riparian restoration projects can affect local geomorphology and the abundance of fish. Dense vegetative cover in riparian zones and similar or analogous habitats in both forested and nonforested reaches, the relatively small scale of the nonforested reaches, and the low statistical power to detect differences in abundance of rare species may have limited the observed differences between forested and nonforested reaches. There was a strong urbanization gradient, with reductions of intolerant species and increases of tolerant species and omnivores with increasing urbanization. Interactions between riparian vegetation type and urbanization were found for blacknose dace, creek chub, tesselated darter, and the proportion of biomass of lithophilic spawners. The study did not provide consistent support for the hypotheses that responses of fish to riparian vegetation would be overwhelmed by urban degradation or insignificant at low urbanization. 相似文献
94.
George N. Zaimes Richard C. Schultz Thomas M. Isenhart 《Journal of the American Water Resources Association》2008,44(4):935-947
Abstract: Phosphorus and sediment are major nonpoint source pollutants that degrade water quality. Streambank erosion can contribute a significant percentage of the phosphorus and sediment load in streams. Riparian land‐uses can heavily influence streambank erosion. The objective of this study was to compare streambank erosion along reaches of row‐cropped fields, continuous, rotational and intensive rotational grazed pastures, pastures where cattle were fenced out of the stream, grass filters and riparian forest buffers, in three physiographic regions of Iowa. Streambank erosion was measured by surveying the extent of severely eroding banks within each riparian land‐use reach and randomly establishing pin plots on subsets of those eroding banks. Based on these measurements, streambank erosion rate, erosion activity, maximum pin plot erosion rate, percentage of streambank length with severely eroding banks, and soil and phosphorus losses per unit length of stream reach were compared among the riparian land‐uses. Riparian forest buffers had the lowest streambank erosion rate (15‐46 mm/year) and contributed the least soil (5‐18 tonne/km/year) and phosphorus (2‐6 kg/km/year) to stream channels. Riparian forest buffers were followed by grass filters (erosion rates 41‐106 mm/year, soil losses 22‐47 tonne/km/year, phosphorus losses 9‐14 kg/km/year) and pastures where cattle were fenced out of the stream (erosion rates 22‐58 mm/year, soil losses 6‐61 tonne/km/year, phosphorus losses 3‐34 kg/km/year). The streambank erosion rates for the continuous, rotational, and intensive rotational pastures were 101‐171, 104‐122, and 94‐170 mm/year, respectively. The soil losses for the continuous, rotational, and intensive rotational pastures were 197‐264, 94‐266, and 124‐153 tonne/km/year, respectively, while the phosphorus losses were 71‐123, 37‐122, and 66 kg/km/year, respectively. The only significant differences for these pasture practices were found among the percentage of severely eroding bank lengths with intensive rotational grazed pastures having the least compared to the continuous and rotational grazed pastures. Row‐cropped fields had the highest streambank erosion rates (239 mm/year) and soil losses (304 tonne/km/year) and very high phosphorus losses (108 kg/km/year). 相似文献
95.
“四沿”化工企业污水处理系统安全事故状态下负荷缓冲及安全环境(SE)联锁探讨 总被引:2,自引:1,他引:1
在对"四沿"(沿江、沿河、沿湖、沿海)化工行业污水处理方法及流程特点总结的基础上,归纳出应对水力和污染物冲击负荷的缓冲方法。为克服缓冲控制能力有限的缺点,提出一种新方法——SE(安全和环境)联锁,以期达到完善管理、提高控制效果的目的,并详细阐述了该方法在管理及技术层面的实施途径。 相似文献
96.
Interactions between water and land in The Netherlands 总被引:1,自引:0,他引:1
The Netherlands are one of the most densely populated coastal countries in the world and there is only limited space for living,
working, transport and recreation, while there is also the need to preserve and expand valuable natural habitats. In order
to solve many existing and future conflicts of interest, and in order to create ‘added value’, strategies are developed to
optimize the use of water-land systems.
The principle of ‘building with nature’ is applied in order to integrate land in sea and water in land in such a way that
future generations will be able to use coastal resources in a sustainable way, including a minimal effort to maintain the
coastline and the promotion of a multiple-use system.
The concept of Integrated multifunctional sustainable coastal zone development is introduced. This concept deals with a balanced
approach to the lack of space for present and future coastal uses in relation to each other, to the hinterland, and to the
sea. Flexible master plans are developed, taking into account many functions of the coastal zone, and facilitating adaptation
to future developments—e.g. impacts of climate change and relative sea level rise. In this regard increasing the flexibility
of the coastal zone is of vital importance.
Large-scale coastal land reclamations in The Netherlands are dealt with, based on two different principles: (1) polder systems
(low lying land reclamations surrounded and protected by dikes), (2) systems of ‘building with nature’—land reclamation protected
by man-made foreshores, beaches and dunes. In the latter type new flexible dynamic-equilibrium coasts are created for many
functions, while coastal vulnerability is reduced and a flexible coast is developed. 相似文献
97.
三峡大坝每年周期性“蓄水-放水”,形成水位落差巨大的消落带,库区内污染物环境地球化学行为随之发生变化.以冬季淹没期消落带多环芳烃为研究对象,采集成对大气(n=16)、植物(n=12)和土壤样品(n=12),采用气相色谱/质谱法(GC/MS),分析USEPA 16PAHs浓度水平,解析来源,估算大气地表、大气-植物等多介质交换通量.结果表明:大气、土壤和植物中PAHs浓度为5.65~13.47ng/m3、70.86~13 5.44ng/g和78.23~1084.72ng/g,平均值分别为(8.58±2.78) ng/m3、(90.10±22.18) ng/g和(360.36±309.54) ng/g.大气中PAHs以2~3环为主(62.3%),植物中PAHs以3~4环为主(73.7%),土壤中PAHs以3环和5环为主(52.1%).特征分子比值法揭示煤、生物质燃烧是植物PAHs的主要来源,以石油为主的化石燃料燃烧是大气和土壤PAHs主要来源.“一室模型”表明,植物吸收PAHs的主要途径为植物-气相之间动态平衡限制下的气沉降.“逸度模型”表明,3... 相似文献
98.
Almost half (354) of all fish kills (805) in South Carolina, USA, between 1978 and 1988 occurred in the coastal zone. These
kills were analyzed for causative, spatial, and temporal associations as a distinct data set and as one integrated with ambient
water quality monitoring data. Estuarine kills as a result of natural causes accounted for 42.8% followed by man-induced (35.1%)
and undetermined causes (22.1%).
Although general pesticide usage was responsible for 53.9% of man-induced kills, weed control activities around resorts and
municipal areas accounted for slightly more kills (20.9%) than did agricultural (19.8%) or vector control (13.2%) uses. A
dramatic decline in agricultural-related kills has been observed since 1986 as the integrated pest management approach was
adopted by many farmers. When taken with the few kills (12.0%) resulting from wastewaters, this suggests that these two land-use
activities have been successfully managed via existing programs (IPM and NPDES, respectively) to minimize their contributions
to estuarine fish kills.
Ambient trend monitoring data demonstrated no coastal-wide dispersion of pesticide pollution. These data confirmed the nature
of fish kills to be site-specific, near-field events most closely associated with the contiguous land-use practices and intensities.
Typically, fish kill data are considered as event-specific data limited to the bounds of that event only. Our analysis has
shown, however, that a long-term data set, when integrated with ambient water quality data, can assist in regulatory and resource
management decisions for both short- and long-term planning and protection applications. 相似文献
99.
Joseph W. Dellapenna 《Journal of the American Water Resources Association》1994,30(2):197-204
ABSTRACT: Lawyers, engineers, and hydrologists are accustomed to thinking of water law as falling into one of two incompatible models: riparian rights (under which water is allocated by courts according to the relative reasonableness of the competing uses) and appropriative rights (under which water is allocated according to the temporal priority of the competing uses, largely by the action of the water users themselves but perfected by the issuance of an administrative permit). Usually unnoticed is the existence of a third approach, which I have dubbed “regulated riparianism.” Under regulated riparianism, water is allocated by water permits issued after an administrative determination of the reasonableness of the proposed use before the use is commenced. This system, now in place in about half of the states east of Kansas City (plus Hawaii), thus is fundamentally different from either the traditional ripanan rights that it replaces or the appropriative rights found in western states. 相似文献
100.
在则木河断裂带宏观研究的基础上,结合岩石破裂实验成果,对包括1850年大震变形带在内的断裂产物进行定向原态采集、固结、制片和镜下系统观测,从复杂纷呈的变形遗迹中鉴别出微观粘滑与蠕滑标志。最后就有关问题进行了简要讨论. 相似文献