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1.
Pulakesh Das Mukunda Dev Behera Nitesh Patidar Bhabagrahi Sahoo Poonam Tripathi Priti Ranjan Behera S K Srivastava Partha Sarathi Roy Praveen Thakur S P Agrawal Y V N Krishnamurthy 《Journal of Earth System Science》2018,127(2):19
As a catchment phenomenon, land use and land cover change (LULCC) has a great role in influencing the hydrological cycle. In this study, decadal LULC maps of 1985, 1995, 2005 and predicted-2025 of the Subarnarekha, Brahmani, Baitarani, Mahanadi and Nagavali River basins of eastern India were analyzed in the framework of the variable infiltration capacity (VIC) macro scale hydrologic model to estimate their relative consequences. The model simulation showed a decrease in ET with 0.0276% during 1985–1995, but a slight increase with 0.0097% during 1995–2005. Conversely, runoff and base flow showed an overall increasing trend with 0.0319 and 0.0041% respectively during 1985–1995. In response to the predicted LULC in 2025, the VIC model simulation estimated reduction of ET with 0.0851% with an increase of runoff by 0.051%. Among the vegetation parameters, leaf area index (LAI) emerged as the most sensitive one to alter the simulated water balance. LULC alterations via deforestation, urbanization, cropland expansions led to reduced canopy cover for interception and transpiration that in turn contributed to overall decrease in ET and increase in runoff and base flow. This study reiterates changes in the hydrology due to LULCC, thereby providing useful inputs for integrated water resources management in the principle of sustained ecology. 相似文献
2.
Vaibhav Garg S. P. Aggarwal Prasun K. Gupta Bhaskar R. Nikam Praveen K. Thakur S. K. Srivastav A. Senthil Kumar 《Environmental Earth Sciences》2017,76(18):635
The sustainability of water resources mainly depends on planning and management of land use; a small change in it may affect water yield largely, as both are linked through relevant hydrological processes, explicitly. However, human activities, especially a significant increase in population, in-migration and accelerated socio-economic activities, are constantly modifying the land use and land cover (LULC) pattern. The impact of such changes in LULC on the hydrological regime of a basin is of widespread concern and a great challenge to the water resource engineers. While studying these impacts, the issue that prevails is the selection of a hydrological model that may be able to accommodate spatial and temporal dynamics of the basin with higher accuracy. Therefore, in the present study, the capabilities of variable infiltration capacity hydrological model to hydrologically simulate the basin under varying LULC scenarios have been investigated. For the present analysis, the Pennar River Basin, Andhra Pradesh, which falls under a water scarce region in India, has been chosen. The water balance components such as runoff potential, evapotranspiration (ET) and baseflow of Pennar Basin have been simulated under different LULC scenarios to study the impact of change on hydrological regime of a basin. Majorly, increase in built-up (13.94% approx.) and decrease in deciduous forest cover (2.44%) are the significant changes observed in the basin during the last three decades. It was found that the impact of LULC change on hydrology is balancing out at basin scale (considering the entire basin, while routing the runoff at the basin outlet). Therefore, an analysis on spatial variation in each of the water balance components considered in the study was done at grid scale. It was observed that the impact of LULC is considerable spatially at grid level, and the maximum increase of 265 mm (1985–2005) and the decrease of 48 mm (1985–1995) in runoff generation at grid were estimated. On the contrary, ET component showed the maximum increase of 400 and decrease of 570 mm under different LULC change scenario. Similarly, in the base flow parameter, an increase of 70 mm and the decrease of 100 mm were observed. It was noticed that the upper basin is showing an increasing trend in almost all hydrological components as compared to the lower basin. Based on this basin scale study, it was concluded that change in the land cover alters the hydrology; however, it needs to be studied at finer spatial scale rather than the entire basin as a whole. The information like the spatial variation in hydrological components may be very useful for local authority and decision-makers to plan mitigation strategies accordingly. 相似文献
3.
Coupling a glacier melt model to the Variable Infiltration Capacity (VIC) model for hydrological modeling in north-western China 总被引：3，自引：0，他引：3
Qiudong Zhao Baisheng Ye Yongjian Ding Shiqiang Zhang Shuhua Yi Jian Wang Donghui Shangguan Chuancheng Zhao Haidong Han 《Environmental Earth Sciences》2013,68(1):87-101
For the sustainable utilization of rivers in the mid and downstream regions, it is essential that land surface hydrological processes are quantified in high cold mountains regions, as it is in these regions where most of the larger rivers in China acquire their headstreams. Glaciers are one of the most important water resources of north-west China. However, they are seldom explicitly considered within hydrological models, and climate-change effects on glaciers, permafrost and snow cover will have increasingly important consequences for runoff. In this study, an energy-balance ice-melt model was integrated within the Variable Infiltration Capacity (VIC) macroscale hydrological model. The extended VIC model was applied to simulate the hydrological processes in the Aksu River basin, a large mountainous and glaciered catchment in north-west China. The runoff components and their response to climate change were analyzed based on the simulated and observed data. The model showed an acceptable performance, and achieved an efficiency coefficient R 2 ≈ 0.8 for the complete simulation period. The results indicate that a large proportion of the catchment runoff is derived from ice meltwater and snowmelt water. In addition, over the last 38 years, rising temperature caused an extension in the snow/ice melting period and a reduction in the seasonality signal of runoff. Due to teh increased precipitation runoff, the Aksu catchment annual runoff had a positive trend, increasing by about 40.00 × 106 m3 per year, or 25.7 %. 相似文献
4.
基于CMIP5和VIC模型的长江上游主要水文过程变化趋势预测 总被引：2，自引：0，他引：2
基于长江上游流域82个气象站点的实测数据和国际耦合模式比较计划第5阶段(Coupled Model Intercomparison Project phase 5,CMIP5)的2种排放情景下的8个气候模式1961～2099年的降水、气温数据,通过等距离累积分布函数法(Equidistance Cumulative Distribution Function Method,EDCDFm)进行气候模式的统计降尺度。在此基础上,构建0.5°×0.5°网格空间分辨率的可变下渗容量水文模型(Variable Infiltration Capacity,VIC),对历史流量进行模拟,并进一步模拟分析长江上游流域2006～2099年径流量、蒸散发的时空演变趋势。结果表明:VIC水文模型能够较好地模拟研究区的水文过程,从长江上游流域未来时期(2006～2099)主要水文过程变化趋势的预测来看,径流量变化趋势不明显、蒸散发呈增加趋势。此研究对于合理规划配置长江流域水资源及为气候影响评价和决策系统提供科技支撑具有重要意义。 相似文献
5.
6.
This work evaluates the changes of nitrate-nitrogen (NO3-N), ammonium-nitrogen (NH4-N), total phosphorus (P) and chemical oxygen demand (COD) concentrations in stream waters as related to the land use/land cover (LULC) alterations within eight small (5–39 km2) tile-drained catchments in the southern part of The Czech Republic in the period 1993–2010, when massive grassing of arable land took place. The robust tools of seasonal Mann–Kendall trend test and LOcally WEighted Scatterplot Smoothing methods were employed to reveal trends of the monitored parameters with adjustment to hydrology. Using principal component analysis and multiple regressions, statistically significant factors with highest impacts on the assessed water quality parameters were identified. Besides indicators of LULC changes in the catchments and their various zones, information of built tile drainage systems were used along with factors reflecting point pollution sources such as the population number, sewerage type and proximity to a watercourse, effectiveness of wastewater treatment, and number of livestock units. The change in LULC was essential only for NO3-N concentrations, when grassing of arable land, presence of water ponds, areas of permanent cultures and also areas of drained land explained up to 90.6 % NO3-N variability and nitrate-nitrogen concentrations showed a significantly decreasing trend in all monitored catchments during the evaluated period. LULC changes within infiltration vulnerable zones were discovered as less important for the assessed water quality parameters compared to LULC changes in the whole catchment area. However, for NH4-N, P and COD, the results did not enable a definite quantification of the effects of LULC changes. The influence of non-point pollution sources on these parameters was revealed as uncertain and was heavily overshadowed by point sources, in particular by wastewater management, and livestock numbers, although the proportion of arable land in tile drainage subcatchments was discovered fundamental in case of the COD. The increasing numbers of livestock, population, and changes in sewage treatment led in some catchments to significant worsening of water quality. Achieved findings may be critical for supporting water quality policy and management decisions. 相似文献
7.
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8.
环境变化影响区域水资源的可持续开发利用,导致水文过程出现非平稳特征,需发展非平稳水文干旱评估方法。选取渭河流域为研究区,依据流域内2个水文站、62个雨量站和24个气象站1961-2013年数据,基于可变下渗容量模型定量分离气候变化和人类活动对径流衰减的贡献;采用标准化径流指数（Standardized Runoff Index, SRI）剖析水文干旱时空演变特征;提出多种SRI参数化方案,对比评定各方案表征非平稳干旱的合理性以及环境变化对干旱演变的影响作用。结果表明:自1991年以来渭河流域年径流量呈显著衰减趋势,人类活动是径流演变的主要因素,对咸阳和华县站径流量变化的贡献率分别为-66.7%和-71.0%;时变参数方案计算的干旱指数能合理重建历史水文干旱序列;人类活动是渭河流域1991年以来短历时水文干旱发生的主导因素,气候变化主要影响长历时旱涝的演变趋势。 相似文献
9.
Hossein Mojaddadi Rizeei Biswajeet Pradhan Maryam Adel Saharkhiz 《Arabian Journal of Geosciences》2018,11(3):53
The effects of climate and land use/land cover (LULC) dynamics have directly affected the surface runoff and flooding events. Hence, current study proposes a full-packaged model to monitor the changes in surface runoff in addition to forecast of the future surface runoff based on LULC and precipitation variations. On one hand, six different LULC classes were extracted from Spot-5 satellite image. Conjointly, land transformation model (LTM) was used to detect the LULC pixel changes from 2000 to 2010 as well as predict the 2020 ones. On the other hand, the time series-autoregressive integrated moving average (ARIMA) model was applied to forecast the amount of rainfall in 2020. The ARIMA parameters were calibrated and fitted by latest Taguchi method. To simulate the maximum probable surface runoff, distributed soil conservation service-curve number (SCS-CN) model was applied. The comparison results showed that firstly, deforestation and urbanization have been occurred upon the given time, and they are anticipated to increase as well. Secondly, the amount of rainfall has non-stationary declined since 2000 till 2015 and this trend is estimated to continue by 2020. Thirdly, due to damaging changes in LULC, the surface runoff has been also increased till 2010 and it is forecasted to gradually exceed by 2020. Generally, model calibrations and accuracy assessments have been indicated, using distributed-GIS-based SCS-CN model in combination with the LTM and ARIMA models are an efficient and reliable approach for detecting, monitoring, and forecasting surface runoff. 相似文献
10.
Costache Romulus Fontanine Iulia Corodescu Ema 《Central European Journal of Geosciences》2014,6(3):363-372
Sǎrǎ?el River basin, which is located in Curvature Subcarpahian area, has been facing an obvious increase in frequency of hydrological risk phenomena, associated with torrential events, during the last years. This trend is highly related to the increase in frequency of the extreme climatic phenomena and to the land use changes. The present study is aimed to highlight the spatial and quantitative changes occurred in surface runoff depth in Sǎrǎ?el catchment, between 1990–2006. This purpose was reached by estimating the surface runoff depth assignable to the average annual rainfall, by means of SCS-CN method, which was integrated into the GIS environment through the ArcCN-Runoff extension, for ArcGIS 10.1. In order to compute the surface runoff depth, by CN method, the land cover and the hydrological soil classes were introduced as vector (polygon data), while the curve number and the average annual rainfall were introduced as tables. After spatially modeling the surface runoff depth for the two years, the 1990 raster dataset was subtracted from the 2006 raster dataset, in order to highlight the changes in surface runoff depth. 相似文献
11.
Integration of vegetation processes in rain–runoff (RR) models significantly affects runoff response by influencing evapotranspiration in mesoscale catchments. However, it is impossible to interpret the impacts of vegetation processes on runoff simulations in macroscale catchments using results from mesoscale catchments. Few studies involved vegetation process impacts on hydrological simulations by integrating daily vegetation information into conceptual RR models of macroscale catchments. In this study, we integrated the remotely sensed leaf area index (LAI) from the Moderate Resolution Imaging Spectroradiometer (MODIS) into a daily Distributed Time-Variant Gain Model (DTVGM). Then, this study assessed the performances of two DTVGM versions, with and without vegetation processes, in the Wei River catchment, China. The results showed that: (1) Integration of MODIS-LAI into the DTVGM model improved the calibration and runoff simulation results of the initial DTVGM model. (2) Inclusion of vegetation processes in the DTVGM changed the simulated proportions of water balance components in the hydrological model and made the simulation of water balance components more accurate. (3) The fact that inclusion of vegetation processes could improve the hydrological simulation performance of the daily conceptual RR model in the macroscale catchment was consistent with studies in mesoscale catchment. 相似文献
12.
Flooding in urban area is a major natural hazard causing loss of life and damage to property and infrastructure. The major causes of urban floods include increase in precipitation due to climate change effect, drastic change in land use–land cover (LULC) and related hydrological impacts. In this study, the change in LULC between the years 1966 and 2009 is estimated from the toposheets and satellite images for the catchment of Poisar River in Mumbai, India. The delineated catchment area of the Poisar River is 20.19 km2. For the study area, there is an increase in built-up area from 16.64 to 44.08% and reduction in open space from 43.09 to 7.38% with reference to total catchment area between the years 1966 and 2009. For the flood assessment, an integrated approach of Hydrological Engineering Centre-Hydrological Modeling System (HEC-HMS), HEC-GeoHMS and HEC-River analysis system (HEC-RAS) with HEC-GeoRAS has been used. These models are integrated with geographic information system (GIS) and remote sensing data to develop a regional model for the estimation of flood plain extent and flood hazard analysis. The impact of LULC change and effects of detention ponds on surface runoff as well as flood plain extent for different return periods have been analyzed, and flood plain maps are developed. From the analysis, it is observed that there is an increase in peak discharge from 2.6 to 20.9% for LULC change between the years 1966 and 2009 for the return periods of 200, 100, 50, 25, 10 and 2 years. For the LULC of year 2009, there is a decrease in peak discharge from 10.7% for 2-year return period to 34.5% for 200-year return period due to provision of detention ponds. There is also an increase in flood plain extent from 14.22 to 42.5% for return periods of 10, 25, 50 and 100 years for LULC change between the year 1966 and year 2009. There is decrease in flood extent from 4.5% for 25-year return period to 7.7% for 100-year return period and decrease in total flood hazard area by 14.9% due to provisions of detention pond for LULC of year 2009. The results indicate that for low return period rainfall events, the hydrological impacts are higher due to geographic characteristics of the region. The provision of detention ponds reduces the peak discharge as well as the extent of the flooded area, flood depth and flood hazard considerably. The flood plain maps and flood hazard maps generated in this study can be used by the Municipal Corporation for flood disaster and mitigation planning. The integration of available software models with GIS and remote sensing proves to be very effective for flood disaster and mitigation management planning and measures. 相似文献
13.
在地理信息系统ArcGIS环境下,结合1987-2001年的水文资料,用Spatial Analyst、Hydrologic Modeling等扩展模块,对祁连山中段北坡大野口河流域和海潮坝河流域的景观格局与水文特征进行比较分析,结果表明:大野口河流域的景观组分以低海拔的草地和乔木林占优势,草地所占面积最大,整个景观较为破碎;海潮坝河流域的景观组分以高海拔的裸地和灌丛占优势,裸地所占面积最大,景观破碎化程度相对较低。大野口河流域的蒸散发占降水量的61%,流域径流系数为0.39;而海潮坝河流域的蒸散发占降水量的41%,流域径流系数为0.59。研究表明,导致两流域生态水文效应相差较大的主要原因是两流域不同的景观格局。 相似文献
14.
天山南坡高冰川覆盖率的木扎提河流域水文过程对气候变化的响应 总被引：5，自引：5，他引：0
木扎提河是天山南坡冰川面积覆盖率最大（48.2%）的河流, 流域径流过程对气候变化极为敏感, 为了合理管理和规划水资源, 确保水资源的可持续利用, 亟需定量评估气候变化对该流域水文过程的影响。以VIC-CAS分布式水文模型为计算平台, 利用实测的径流和两次冰川编目间的冰川面积变化数据开展了模型的多目标参数化校正和验证, 有效提高了模拟结果的“真实性”, 然后通过数值模拟结果结合观测数据定量解析了流域径流的组成、 变化特征及对气候变化的响应机理。结果表明： 木扎提河总径流集中在暖季（5 - 9月）, 占全年总径流量的77.9%, 冰川径流、 融雪径流和降雨径流分别占总径流量的66.6%、 26.4%和7.0%。1971 - 2010年木扎提河流域气温和降水呈显著增加趋势, 由于降水的增加, 降雨和融雪径流均呈增加趋势, 但冰川径流呈现明显减少趋势, 导致总径流呈现下降趋势。在RCP4.5情景下, 未来该流域气温呈现明显升高趋势, 降水表现为微弱下降趋势; 气候变暖后, 更多降水以降雨形式发生, 未来降雨径流将明显增加, 降雪和融雪径流已于20世纪90年代达到峰值, 随后明显减少; 冰川面积将持续萎缩, 冰川径流于21世纪10年代达到拐点, 随后明显减少, 导致河道总径流量也将明显减少。 相似文献
15.
《地学前缘(英文版)》2023,14(4):101542
There is no doubt that land cover and climate changes have consequences on landslide activity, but it is still an open issue to assess and quantify their impacts. Wanzhou County in southwest China was selected as the test area to study rainfall-induced shallow landslide susceptibility under the future changes of land use and land cover (LULC) and climate. We used a high-resolution meteorological precipitation dataset and frequency distribution model to analyse the present extreme and antecedent rainfall conditions related to landslide activity. The future climate change factors were obtained from a 4-member multi-model ensemble that was derived from statistically downscaled regional climate simulations. The future LULC maps were simulated by the land change modeller (LCM) integrated into IDRISI Selva software. A total of six scenarios were defined by considering the rainfall (antecedent conditions and extreme events) and LULC changes towards two time periods (mid and late XXI century). A physically-based model was used to assess landslide susceptibility under these different scenarios. The results showed that the magnitude of both antecedent effective recharge and event rainfall in the region will evidently increase in the future. Under the scenario with a return period of 100 years, the antecedent rainfall in summer will increase by up to 63% whereas the event rainfall will increase by up to 54% for the late 21st century. The most considerable changes of LULC will be the increase of forest cover and the decrease of farming land. The magnitude of this change can reach + 22.1% (forest) and –9.2% (farmland) from 2010 until 2100, respectively. We found that the negative impact of climate change on landslide susceptibility is greater than the stabilizing effect of LULC change, leading to an over decrease in stability over the study area. This is one of the first studies across Asia to assess and quantify changes of regional landslide susceptibility under scenarios driven by LULC and climate change. Our results aim to guide land use planning and climate change mitigation considerations to reduce landslide risk. 相似文献
16.
针对1960—2010年径流量显著减少的中国主要流域,包括松花江、辽河、海河、黄河和汉江等,选择其上游地区受人类直接取用水影响较少的山区小流域,分析径流变化及其原因.采用基于Budyko假设的流域水热耦合平衡方程,估计了流域年径流量变化的气候弹性系数和下垫面弹性系数,并对各流域径流变化进行了归因分析.结果表明,在气候较为湿润的地区,径流对气候和下垫面变化均不敏感;在气候较为干燥的地区,径流对气候和下垫面变化都更为敏感,且区域差异性明显.潜在蒸散发的变化对径流减少的影响微弱,降水减少和下垫面变化是径流减少的主导因素,其中人类活动导致的下垫面变化对径流减少的影响尤为显著.对比两个阶段的径流变化归因分析结果,近10年间流域下垫面变化对年径流量的影响程度较前20年有显著增加.通过分析近30年的归一化植被指数(NDVI)数据发现,植被覆盖改善是下垫面变化的重要原因,说明中国水土保持工程发挥了显著生态效益的同时也导致了流域径流减小. 相似文献
17.
Nader Saadatkhah Mohammadreza Hadad Tehrani Shattri Mansor Zailani Khuzaimah Azman Kassim Reza Saadatkhah 《Arabian Journal of Geosciences》2016,9(17):687
In the current years, changing the land cover/land use had serious hydrological impacts affecting the flood events in the Kelantan River basin. The flood events at the east coast of the peninsular Malaysia got highly affected in the recent decades due to several factors like urbanisation, rapid changes in the utilisation of land and lack of meteorological (i.e. change in climate) and developmental monitoring and planning. The Kelantan River basin has been highly influenced due to a rapid change in land use during 1984 to 2013, which occurred in the form of transformation of agricultural area and deforestation (logging activities). In order to evaluate the influence of the modifications in land cover on the flood events, two hydrological regional models of rainfall-induced runoff event, the Hydrologic Engineering Center (HEC)-Hydrologic Modeling System (HMS) model and improved transient rainfall infiltration and grid-based regional model (Improved TRIGRS), were employed in this study. The responses of land cover changes on the peak flow and runoff volume were investigated using 10 days of hourly rainfall events from 20 December to the end of December 2014 at the study area. The usage of two hydrological models defined that the changes in land use/land cover caused momentous changes in hydrological response towards water flow. The outcomes also revealed that the increase of severe water flow at the study area is a function of urbanisation and deforestation, particularly in the conversion of the forest area to the less canopy coverage, for example, oil palm, mixed agriculture and rubber. The monsoon season floods and runoff escalate in the cleared land or low-density vegetation area, while the normal flow gets the contribution from interflow generated from secondary jungle and forested areas. 相似文献
18.
汉江流域未来降水径流预测分析研究 总被引：7，自引：0，他引：7
本文应用统计降尺度法将全球气候模式和VIC分布式水文模型进行耦合,研究未来A2气候情景下汉江流域降水径流变化情况.首先应用基于光滑支持向量机的统计降尺度法在全球气候模式CGCM2和HadCM3的A2气候情景下,分别预测未来汉江流域日降水、气温过程,然后将预测降水过程作为VIC模型的输入,模拟预测未来汉江流域径流过程.研究结果表明,在CGCM2气候模式下,2020s(2011～2040年)时期汉江流域径流小于基准年,2050s(2041～2070年)时期与基准年基本相当,2080s(2071～2100年)时期大于基准年;在HadCM3气候模式下,2020s时期汉江流域径流小于基准年,2050s和2080s时期均比基准年增加;降水、气温预测结果与径流基本一致. 相似文献
19.
Shattri Mansor Nader Saadatkhah Zailani Khuzaimah Arnis Asmat Nor Aizam Adnan Siti Noradzah Adam 《Natural Hazards》2018,93(2):739-764
The objective of this paper is to develop a spatial temporal runoff modelling of local rainfall patterns effect on the plant cover hilly lands in Kelantan River Basin. Rainfall interception loss based on leaf area index, loss/infiltration on the ground surface, and runoff calculation were considered as the main plant cover effects on the runoff volume. In this regard, a hydrological and geotechnical grid-based regional model (integrated model) was performed using Microsoft Excel® and GIS framework system for deterministic modelling of rainfall-induced runoff by incorporating plant cover effects. The infiltration process of the current model was integrated with the precipitation distribution method and rainfall interception approach while the runoff analysis of integrated model was employed based on loss/infiltration water on the ground surface with consideration of water interception loss by canopy and the remaining surface water. In the following, the spatial temporal analysis of rainfall-induced runoff was performed using 10 days of hourly rainfall events at the end of December 2014 in Kelantan River Basin. The corresponding changes in pressure head and consequent rate of infiltration were calculated during rainfall events. Subsequently, flood volume is computed using local rainfall patterns, along with water interception loss and the remaining surface water in the study area. The results showed the land cover changes caused significant differences in hydrological response to surface water. The increase in runoff volume of the Kelantan River Basin is as a function of deforestation and urbanization, especially converting the forest area to agricultural land (i.e. rubber and mixed agriculture). 相似文献
20.
Updated rainfall data to 2006 confirm that the Sahelian rainfall has increased since the end of the 1990s, but the annual average rainfall is still as low as during the drought of the 1970s. The decrease of rainfall is higher in the Northwest and lower in the Southeast Sahel. The increase of temperature over West Africa during the end of the 20th century induced an increase of Potential Evaporation, which might reduce the runoff. However, the joint effect of climate change and of human activities on land cover over more than three decades is responsible for an increase of the runoff coefficients of the West African Sahelian Rivers since the 1970s, despite the rainfall shortage during the same period, as revealed by the analysis of runoff from Mauritania, Burkina-Faso and Niger. The runoff coefficients have increased in regions with less than 750 mm of annual rainfall, under Sahelian and subdesertic climates, leading to increased flood peaks, occurring earlier in the season. Even if it is difficult to separate which part of this runoff coefficient increase is due to climate change alone or to human impact on land cover, the highest values are observed in the most inhabited areas, where land cover is dominated by cultivated areas. This climatic/human impact on land cover is so huge that it has changed since decades the hydrological regimes of the Sahelian Rivers, from the small watershed to the largest one, such as the Niger River at Niamey. 相似文献