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1.
This study presents the evolution of agreements between the governments of Canadaand Québec on flood damage reduction. In Québec, the implementation of a regulation about building in floodplains came about in 1983–1984. Today, this regulation takes the form of a policy called ``Policy of shores, littoral and floodplain protection'. Municipalities must adopt rules that concur with the principles of this policy.The Chaudiére River basin was selected for analysis of urban developmentduring the period following the application of building rules in flood-risk areas.Despite the ban on building in the strong current zone (0–20 year return periodflood zone), many buildings, essentially residential, have been erected in thiszone. These new constructions generally account for a low percentage of thetotal property value in the 0–100 year flooding area, but are legal since theyare connected to a water and sewage network that existed prior to the officialfloodplain regulation.Flood damage along the Chaudiére River will tend to increase for two reasons.Firstly, while respecting the policy mentioned above, sites are still available infloodplains for future development. Secondly, no structural flood protection workshave been erected in view of the fact they are only marginally profitable from anbenefit-cost point of view. 相似文献
2.
Tauseef Ahmad Ansari Yashwant B. Katpatal A. D. Vasudeo 《Arabian Journal of Geosciences》2016,9(18):702
The changing land use due to rapid urbanization has profound impact on the runoff in urban watersheds. The spatial analysis in urban watersheds is felt necessary for management of surface and subsurface water regimes. Significant increase in impervious zones was observed in Nagpur urban watersheds between 2000 and 2012 having impacts on runoff, and even flash floods were observed. This study presents spatial and temporal impacts of change in urban built-up area on curve number (CN) and runoff during the years 2000 and 2012. The study also analyzes effect of slope on CN values and shows that CN increases with slope. High-resolution satellite images were used to map impervious surface areas (ISAs) which show an increase of 0.9 to 34 % during 2000–2012. Spearman’s and Pearson’s coefficients have been generated to establish relationship between runoff, impervious surface areas, vegetation index, slope, and runoff coefficient. It has been hypothetically assumed that if 100, 50, and 25 % rooftop rainwater harvesting is considered, the estimated runoff reduces in 2012 as compared to the year 2000. The study suggests that increase in impervious areas within urban watersheds can be utilized for groundwater augmentation adopting rooftop rainwater-harvesting techniques and to prevent flash floods. 相似文献
3.
Hassan Abdel Kader Saleh 《GeoJournal》1995,37(1):125-132
In spite of Jordan's insignificant natural resources and geopolitical problems, industrial development is being emphasized in Jordan since 1972. Industries are now the second largest sector of economy. Industries contributed 10% of the GDP in 1972, 19.5% in 1989 and 17.4% in 1993. This is remarkable as the national investment in industries is declining. The investments for industrial development was 30% of the total national investment in five year development plans (1976–1980), 23% in the next plan (1981–1985), and 13% in the following plan (1986–1990).The number of; industries has increased from 2500 in 1959 to 4684 in 1974, to 8533 in 1984, and 18600 in 1992. The employment or labor force also increased from 10,000 in 1959 to 70,000 in 1988, and to 110,000 in 1992. It represents about 16.4% of the total labor force in Jordan, the index number of industrial production also increased from (100) in 1979 which was the same base year, to (151) in 1983 to (205) in 1987 and to (215) in 1993. The study was based on three hypotheses: (i) the magnitude varies from one industry to another at the national (Jordan) and local (governorate levels), (ii) temporal change in the magnitude of industries has taken place during the period 1979–1992, (iii) the temporal change in the magnitude of industries was positive in some industries and negative in others. 相似文献
4.
Rispana River flows through the heart of Dehradun, the capital city of Uttarakhand State, India. Uttarakhand had separated from Uttar Pradesh State in the year 2000; since then, Dehradun City has witnessed numerous changes. Both urban sprawl and densification were noticed, with around a 32% increase in population. The city had faced recurrent high runoff and urban flood situations in these last 2 decades. Therefore, the study was conducted to detect the change in land use/land cover (LULC), especially urbanization, through remote sensing data; and later to determine the impacts of such changes on the Rispana watershed hydrology. The LULC maps for the year 2003 and the 2017 were generated through supervised classification technique using the Landsat Series satellite datasets. The LULC change analysis depicted that mainly the urban settlement class increased with significant area among other classes from the year 2003–2017. It was noticed that majorly agriculture and fallow land (8.18 km2, which is 13.52% of total watershed area) converted to urban, increasing the impervious area. Almost all the municipal wards, falling in the Rispana watershed, showed urbanization during the said period, with an increase of as high as 71%. The change in LULC or effect of urbanization on the hydrological response of the watershed was assessed using the most widely used Natural Resources Conservation Services Curve Number method. It was noticed that the area under moderated runoff potential (approx. 10.23 km2) steeply increased during the lean season, whereas, high runoff potential zones (5 km2) increased significantly under wet season. Therefore, it was concluded that an increase in impervious surface resulted in high runoff generation. Further, such LULC change along with climate might lead to high runoff within the watershed, which the present storm drainage network could not withstand. The situation generally led to urban floods and affected urban dwellers regularly. Therefore, it is critical to assess the hydrological impacts of LULC change for land use planning and water resource management. Furthermore, under the smart city project, the local government has various plans to improve present infrastructure; therefore, it becomes necessary to incorporate such observations in the policies.
相似文献5.
Marina Yordanova 《GeoJournal》1996,40(4):371-378
Hydrological changes in four stream basins situated on the northern slopes of the Stara Planina range (North Bulgaria) and in the Rodopi massif (South Bulgaria) have been investigated during the 1951–1989 time period. Parallel analysis of runoff and precipitation mean annual values have been made, calculating the respective annual ratios compared to the mean of the entire range mean value. Curves of runoff and precipitation frequencies have been developed and analyzed. This investigation establishes that during the 1980s a consistent trend towards significant humidity reduction has occurred. Mean annual deviation values of the last decade compared to the entire period mean annual figure amount to 5–20% and 10–25% for the precipitation and runoff, respectively, with humidity reduction of greater amplitude in the North Bulgarian stream basins. Annual Mean deviations are due to significant moisture reduction during the warm half of the year in North Bulgaria and in the cold half in South Bulgaria. Both regions reflect zonal differences caused by climatic patterns of European if not planetary scale. 相似文献
6.
Elise Van Campo 《Quaternary Research》1986,26(3)
Two marine pollen diagrams for sediments off the southwest coast of India provide a 20,000-yr history of the nearby continental vegetation, determined by the monsoon climate, within the framework of the isotopic stratigraphy. Two important phases of the evolution of the monsoon climate are a very arid period about 22,000–18,000 yr B.P. and a very humid period culminating at 11,000 yr B.P. The very arid period corresponds to the lowest pollen representation of mangrove vegetation, which is used here as an indirect indicator of monsoonal runoff. This aridity is due to a very weak southwest airflow, a great reduction of summer monsoonal rainfall, and reduced runoff of the western Ghats rivers. The extension of the monsoon over India after the last glacial maximum has been a gradual process following the northward progression of the Intertropical Convergene Zone. The very humid period, corresponding to the highest pollen representation of mangrove vegetation and the heaviest summer rainfall, is a climatic response to the maximum summer insolation of the Northern Hemisphere at 11,000 yr B.P. 相似文献
7.
Many regions of the world are experiencing an increase in frequency and intensity of floods. There has been increasing understanding among emergency preparedness and natural disaster planners that rapid urbanization is enhancing the risk from river flooding in urban areas. Many regions of Canada have been exposed to particularly severe floods over the course of the last few years, much of this due to land-use change. This study aims at understanding the risk of flooding for the City of Metro Vancouver, British Columbia, Canada, which is located in the Fraser River Delta. The paper presents a fast, efficient and reliable method that can be used to produce vegetation maps from advanced very high resolution radiometer images and SPOT vegetation maps. A 10-day maximum normalized difference vegetation index maps were produced to assess the dynamics of the urbanization process in Vancouver. Remotely sensed data show a significant decrease in vegetation cover in the Metro Vancouver City between 1984 and 2012. The proposed method can be used as an effective tool for raising early land-use change awareness and assist with flood risk management. Flood risk management has a substantial impact on human health and well-being in urban areas, and this flood risk information will be used to assess the impact of flooding and explore the complex relationship between land-use change, urbanization, flooding and impact on urban dwellers. 相似文献
8.
9.
为了解决暴雨导致的城市内涝,为应急管理提供技术支撑,考虑城市暴雨过程及海绵地表特性,结合城市水文学及水力学原理和芝加哥雨型,建立了SWMM-CCHE2D耦合模型。结合高精度地形数据和降雨、径流实时监测数据,采用SWMM雨洪模型模拟暴雨条件下海绵城市的产流,耦合高精度的二维水动力模型CCHE2D模拟相应的内涝情况。结果表明：暴雨条件下通州海绵区的产汇流具有缓慢下渗和汇流的特性,主要海绵措施的加入对径流削减率会有9.0%~40.6%不同程度的提高,从而减缓内涝,其中,对5年一遇暴雨的效果最显著;在100年一遇暴雨下设计的各种海绵措施中,生物滞留带对径流削减率的提高程度最明显,高达28.4%,透水铺装和绿地也具有较好的效果。 相似文献
10.
The equatorial peatlands of the Kutai lowland of eastern Kalimantan are generally 4–10 m in thickness but some sections exceed 16 m in depth. The deposition of peat commenced about 8000 yrs ago after shallow flooding of the basin by the Mahakam River. The earliest vegetation is a Pandanus swamp which grades upwards to swamp forest dominated by dipterocarps. The peatland has expanded laterally and rivers have maintained narrow levee-channel tracks through the swamp, which has grown vertically in balance with river accretion. Historical fires are associated with extreme El Niño years of drought, but human agency is important. The fires of 1982–1983 and 1997–1998 burnt up to 85% of the vegetation on the peatland. Although charcoal analyses show that fire has occurred throughout the history of the peatland, it is rare in forests remote from rivers until the last 3000 years and only common within the last millennium. Fires are earlier and more frequent in sites accessible from waterways, and floodplains have been widely burnt down to water table or below, forming extensive lakes. 相似文献
11.
Anne-Marie Lzine 《Quaternary Research》1989,32(3)
Pollen and phytogeographic evidence provides a vegetational history of the Sahel for the period 0–18,000 yr B.P. The zonal vegetation fluctuated latitudinally and its most extreme positions occurred at 18,000 and 8500 yr B.P. The first involved a southward shift of the Sahelian wooded grassland to 10°N under the arid conditions of the last glacial maximum. The second change shows a rapid northward migration of humid vegetation: Guinean elements reach 16°N and Sahelo-Sudanian elements extend to the southern margin of the modern Sahara (21°N) when the Atlantic monsoon flux increased. In the middle Holocene the extensive spread of Sudanian elements into the modern Sahelian zone suggests the appearance of a markedly dry season. The modern Sahelian semiarid conditions appeared abruptly at 2000 yr B.P. 相似文献
12.
塔里木河下游生态输水后植被景观格局动态变化研究 总被引：7，自引：3，他引：4
2000-2005年, 塔里木河流域管理局先后7次向塔里木河下游断流区进行了生态输水, 输水河道两岸的植被得到了一定的恢复. 以2000-2005的中巴资源卫星CCD影像为主要数据源, 获得了6 a的植被/非植被二值图, 并计算各年的景观格局指数, 分析了6 a植被景观格局的变化. 结果表明: 植被景观动态度在第四时段(2003-2004年)最大, 为47.83%; 在第三时段(2002-2003年)最小, 为-1.39%; 2000-2005年植被景观的动态变化呈正向趋势. 2000-2005年, 植被景观斑块个数与景观形状指数增加, 蔓延度指数下降了36.9, 斑块结合度指数均高于99, 表明研究区的植被景观破碎化程度、分离程度增加, 而景观类型联通性较高. 植被斑块面积均处于增加趋势且远离河道植被恢复率越小, 但植被景观的比重仍小于50%, 说明非植被类型是研究区的基质类型, 组成了景观的最大斑块. 针对缓冲区Zone 1, 植被景观的平均分维数处于减小趋势且2005年的斑块个数最小, 斑块结合度指数处于增加趋势, 表明近河道区域植被较为稳定, 受生态输水的干扰度较小, 植被景观斑块之间越来越聚集. 6 a间Zone 1的植被最大斑块指数均大于10%, 远高于其它5个缓冲带, 表明离河道越近植被景观的优势度最大. 相似文献
13.
Evolutionary trend of water cycle in Beichuan River Basin of China under the influence of vegetation restoration 
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下载免费PDF全文 To understand the influence of vegetation restoration on the water cycle in semiarid areas, the effects of vegetation restoration on evolution of the key elements of water cycle were clarified by analyzing the evolutionary trend of atmospheric precipitation, ecological consumption water, and surface runoff on a river basin scale on the basis of analytical results of the changes in vegetation coverage and the long-term meteorological and hydrological monitoring data of Beichuan River Basin. The results show that the vegetation cover in the Beichuan River basin has rapidly increased in the hilly and mountainous areas since the 1980s, especially from 2000 to 2019, with the maximum and average vegetation cover rates increased by 14.98% and 52.2%, respectively. During 1956-2016, the annual precipitation in the basin remained relatively stable; the annual surface runoff slightly declined, with an average attenuation rate of 20 million m~3/10 a. The main reason for the runoff decline is the increase in ecological water induced by the vegetation restoration, which has changed the spatial-temporal distribution of the water from atmospheric precipitation in the basin. Spatially, more precipitation was converted into ecological water. As a result, the remnant runoff supplied to the lower reaches reduced accordingly. Temporally, more precipitation participated in the soil water-groundwater cycle, thus prolonging the outward drainage period of the precipitation. Moreover, the large-scale vegetation restoration induced a significant decrease in the surface wind speed, evaporation from water surface and drought index. As a result, a virtuously mutual feedback relationship was formed between the vegetation and meteorological elements. Therefore, vegetation restoration is of great significance for the improvement in the water conservation capacity and semiarid climate conditions in the Beichuan River basin. 相似文献
14.
Desert riparian forest colonization in the lower reaches of Tarim River based on remote sensing analysis 总被引：1，自引：0，他引：1
Guilin Liu Alishir Kurban Huanming Duan Umut Halik Abdimijit Ablekim Luocheng Zhang 《Environmental Earth Sciences》2014,71(10):4579-4589
The ecological water conveyance project that pipes water from Daxihaizi reservoir to lower reaches of Tarim River has been implemented ten times since 2000. After ecological water conveyance, restoration has taken place for vegetation along the dried-up lower reaches of the Tarim River. The changes of vegetation fluctuated yearly due to ecological water conveyance. In order to reveal the detailed process of vegetation changes, remote sensing images from 1999 to 2010 were all classified individually into vegetated and non-vegetated areas using the soil-adjusted vegetation index threshold method. Then inter-annual changes of vegetation over a period of 12 years were obtained using a post-classification change detection technique. Finally, spatial–temporal changes distribution of vegetation cover and its response to ecological water conveyance were analyzed. The results indicate: (1) vegetation area increased by 8.52 % overall after ecological water conveyance. Vegetation between 2003 and 2004 increased dramatically with 45.87 % while vegetation between 2002 and 2003 decreased dramatically with 17.83 %. (2) Vegetation area gain is greater than vegetation loss during 1999–2000, 2001–2002, 2003–2004 and 2009–2010 periods. Although vegetation restoration is obvious from 1999 to 2010, vegetation loss also existed except for the periods above. It indicates that vegetation restoration fluctuated due to ecological water conveyance. (3) Spatial distribution of vegetation restoration presented “strip” distribution along the river and group shaper in the lower terrain area, while spatial distribution of vegetation loss mainly located in the upper reaches of river and area far away from the river. (4) Vegetation restoration area had a positive relative with total ecological water conveyance volume. The scheme and season of ecological water conveyance had also influenced the vegetation restoration. The vegetation change process monitoring, based on continuous remote sensing data, can provide the spatial–temporal distribution of vegetation cover in a large-scale area and scientific evidences for implementing ecological water conveyance in the lower Tarim River. 相似文献
15.
Investigating the period 1983–1994 for western Greece, a possible correlation between the selectivity characteristics of the SES (seismic electric signals of the VAN method) and earthquake parameters has been reported by Uyeda et al. [Uyeda, S., Al-Damegh, K.S., Dologlou, E., Nagao, T., 1999. Some relationship between VAN seismic electric signals (SES) and earthquake parameters, Tectonophysics, 304, 41–55.]. They found that the earthquake source mechanism changed from largely strike-slip type to thrust type at the end of 1987, and this coincided with a shift in the SES sensitive site from Pirgos (PIR) to Ioannina (IOA) VAN station. Here, we report the results for the period January 1, 2002–July 25, 2004, during which the SES sensitive site of PIR became again active, after a 10-year period of “quiescence”. This activation was followed by strike slip earthquakes (on August 14, 2003 and March 17, 2004 with magnitude 6.4 and 6.5, respectively) in the Hellenic arc, which provides additional evidence on the correlation reported by Uyeda et al. The SES activities recorded at PIR have been discriminated from “artificial” noise by employing the natural time-domain analysis introduced recently. 相似文献
16.
Interest in the social, technical and demographic problems involved in the development of the world's dryland regions has increased greatly in the recent past. This paper examines the location, size differentiation and growth of urban agglomerations with 100,000 or more inhabitants situated in the extremely arid, arid and and semi-arid regions. A total of 355 such major urban settlements are identified and their distribution and size characteristics are examined. Subsequently, the growth rates recorded by these urban areas in the period 1950–1970 are analyzed at the global, continental and national levels and according to city size. It is estimated that 26.1% of all dryland denizens reside in urban areas with populations of 100,000 or more. In conclusion, the future prospects and planning implications of such dryland urban agglomerations are discussed. 相似文献
17.
Waterlogging risk assessment based on land use/cover change: a case study in Pudong New Area,Shanghai 总被引：2，自引：1，他引：1
Rui-Song Quan Min Liu Min Lu Li-Jia Zhang Jing-Jing Wang Shi-Yuan Xu 《Environmental Earth Sciences》2010,61(6):1113-1121
Waterlogging induced by torrential rain or typhoon in urban areas due to rapid urban development and land cover changes has
been a global hotspot and a potential risk affecting urban habitant lifelines and safety. This paper analyzed the impact of
land use/cover change on the surface runoff and evaluated the waterlogging risk caused by precipitation with different intensities
in Pudong New Area, Shanghai. A simplified urban waterlogging model has been built for the inundated water depth simulation
through the combination of both SCS model and GIS spatial analysis with the consideration of underlying surface characters
in urban area. Based on the simulated depth results, waterlogging risk ranks were further established to evaluate waterlogging
risk of Pudong New Area under different conditions considering social survey results. The results show that the land use structure
and pattern change increases surface runoff depth. Under the assumption of a daily maximum precipitation at 200 mm, the surface
runoff depth increased by 13.19 mm from 1994 to 2006 due to urbanization. On the whole, Heqing, Huaxia tourism area, Chuansha,
Tangzhen and Jichang Town have high waterlogging risk rank, Gaoqiao, Donggou, urban district, Jinqiao, Caolu, Sanlin and Beicai
Town have medium waterlogging risk rank, and Zhangjiang, Gaodong and Huamu Town have low waterlogging risk rank. These results
provide important information for the local government, and the method of waterlogging risk assessment can also be applied
in other cities to provide guidance on waterlogging risk control. 相似文献
18.
近年来北京城区高速发展和大面积的范围扩张,这种开发建设形式使得原有城市内及周边地区的生态遭受到严重破坏,城市下垫面被大量混凝土、沥青和不透水砖覆盖,使得城市原有的暴雨径流条件改变。地处北京城区下游的廊坊市北运河、潮白河流域更是面临着较大的防汛压力,本次分析计算建立了北京城区平均降雨~北运河及潮白河洪量总和之间的关系,为今后进行更加准确、及时的洪峰、洪量预报,来降低甚至防止发生廊坊市北运河、潮白河所在地区暴雨洪水灾害的可能性打下基础。 相似文献
19.
渭河上游典型小流域水文特征差异性分析 总被引：3，自引：2，他引：1
根据渭河流域两个典型小流域的实测水文和气象资料,分析了不同气候和下垫面条件的流域水文特征及其差异性.结果表明:清源河和牛谷河流域的年平均气温呈上升趋势,降水、径流、泥沙、降水径流系数均呈减少趋势;两个流域的降水、径流和泥沙历年变化不一致,1998-2013年清源河流域降水量相对牛谷河流域减少了8.6%,1993-2013年牛谷河的径流相对减少了21.4%,2000-2013年清源河的泥沙相对减少了24.0%;两个流域的面积、河长、海拔、植被覆盖率等流域特征值相对差在-29.4%~-4.5%之间,气温、降水等气候特征值相对差在-27.4%~16.7%之间,而径流特征值相差较大,相对差在-90.2%~-84.7%之间,泥沙特征差异性更大,相对差在292%~347%之间.对气候、下垫面和人类活动对水文要素的影响进行了研究,受人类活动的影响,清源河流域1996-2013年年径流减少11.6%,牛谷河流域1993-2006年年径流减少25.9%,2007-2013年再减少10.5%,研究人类活动的调水减沙效应,对流域综合治理、生态环境建设具有一定的指导意义.同时,充分利用不同小流域实测水文气象数据,分析水文气象要素的变化规律,可以为分布式水文模型研究和中小河流洪水预警预报提供重要依据. 相似文献
20.
The northern shore of Lake Ontario is one of the longest settled parts of Canada beginning around 1795. Accelerated settlement and deforestation after 1840 resulted in massive soil loss from easily-eroded Pleistocene glacial landscapes and the siltation of creeks and lagoons. Channel capacity was reduced but river flow was enhanced by diminished infiltration resulting in straightening of meandering channels, accelerated erosion of stream banks, increased incidence of downstream flooding and large influxes of mud to Lake Ontario. Conservation measures after World War II were successful but rapid urban sprawl after 1970 hardened watersheds and badly impacted the quality and quantity of surface and ground waters flowing to Lake Ontario. The Frenchman’s Bay watershed (27 km2) 50 km east of Toronto is one of the country’s most urbanized (pop: 100,000; 76 % urban cover) and is crossed by Canada’s busiest highway (Highway 401). The watershed drains to Lake Ontario through a coastal lagoon (Frenchman’s Bay) in which pre-settlement postglacial carbonate is abruptly overlain by a ‘European settlement’ mud layer rich in weed pollen and organic debris; the uppermost ‘urban’ part of this deposit shows elevated level of metals and other contaminants. This layer records soil loss after 1840 and more recently, the influx of contaminated urban waters and sediment. Some 7,600 tonnes of road salt have been applied to the lagoon watershed each year producing spikes of brackish surface runoff during winter thaws. Some 50 % of the total salt applied to the entire watershed is conveyed directly to Frenchman’s Bay Lagoon via surface runoff; the rest enters the groundwater system resulting in year-round brackish baseflow to creeks. Chloride continues to be stored in underlying aquifers such that the system has yet to reach a steady-state discharge. Future salinity of baseflow reaching the lagoon can be expected to increase by about 40 %. Rapid migration of contaminated groundwater is facilitated by the widespread presence of thick (<8 m) coarse-grained and heterogeneous fill materials of the built landscape. The watershed is experiencing ongoing changes in land use as urban infilling proceeds. The aquatic ecology of inflowing creeks to the lagoon has been greatly impacted resulting in major loss of wetlands and submergent vegetation and distinct changes in the structure of fish populations. This is the most detailed study of an urban watershed in Canada; lack of knowledge elsewhere is a constraint on the design and testing of mitigation measures and is a major impediment to assessing the impact of ongoing climate change on urban water resources, and the effects of urban runoff on Great Lakes water quality. 相似文献