共查询到10条相似文献,搜索用时 109 毫秒
1.
Sagar Lake is situated in the middle of the Sagar City in the Vindhyan terrain of Bundelkhand region of India at an elevation
of 517 m above mean sea level. The lake surface area and volume are 145 × 104 m2 and 389 × 104 m3 at full tank level. Sedimentation rates and pattern in the lake have been estimated using 137Cs and 210Pb radiometric dating techniques. The lake has been subdivided into eight zones on the basis of sedimentation rate and under
water topography. The sedimentation rate in the lake has been found to vary between 0.30 and 1.08 cm/a depending upon the
location. The estimated mean sedimentation rate is 0.58 ± 0.028 cm/a. The observed sedimentation pattern reveals that the
sedimentation rate decreases from near shore to far shore and minimum at the deepest part of the lake. The estimated useful
life of the lake based on Post-1964 average sedimentation rate is around 467 ± 23 years. 相似文献
2.
Ivars Reinfelds 《Water Resources Management》2011,25(9):2319-2334
Irrigation of pasture forms the greatest single use of irrigation water in Australia yet there has been little monitoring
of its spatial extent and water demands across southeast Australian coastal catchments where irrigated dairy farming forms
an important rural livelihood. This paper provides an analysis of spatio-temporal patterns in the extent of irrigated pasture
in the Bega–Bemboka catchment on the south coast of New South Wales from Landsat imagery, and establishes quantile regression
relationships between metered monthly irrigation abstraction volumes, evaporation and rainfall. Over the metering period (2000–2007),
annual water usage averages 4.8 ML ha − 1 year − 1, with January being the month of highest demand with an annualised usage of 10.4 ML ha − 1 year − 1. Analysis of Landsat imagery indicates that the spatial extent of irrigated pasture across the catchment has increased from
1266 ha in 1983 to 1842 ha by 2002, together with amalgamation of smaller holdings along less reliable streams into larger
parcels along the trunk stream. Quantile regressions to estimate monthly mean and maximum abstraction volumes from monthly
evaporation and rainfall data indicate that abstraction volumes are more closely correlated with evaporation. When combined
with Landsat analyses of the spatial extent of irrigated areas, such relationships enable estimation of catchment-scale hydrological
effects of irrigation abstractions that in turn can help guide regional-scale assessments of the ecological effects and sustainability
of spatially and temporally changing irrigation abstraction volumes. 相似文献
3.
Groundwater is the only source of drinking water for the inhabitants of the Kalahari. Thus understanding spatial and temporal
variations in groundwater recharge is very important and a regional-scale water balance model has therefore been set up for
a 209,149 km2 catchment in north-eastern Namibia and north-western Botswana. The model has a spatial resolution of 1.5 × 1.5 km, daily
model time-steps, and climatic input parameters for 19 years are used. The distributed, GIS-based, process-oriented, physical
water balance model (MODBIL) used in this study considers the major water balance components: precipitation, evapotranspiration,
groundwater recharge, and surface runoff/interflow. Mean precipitation for the study area is 409 mm a−1, while mean actual evapotranspiration is 402 mm a−1 and mean groundwater recharge is 8 mm a−1 (2% of mean annual precipitation). The recharge pattern is mainly influenced by the distribution of soil and vegetation units.
Groundwater recharge shows a high inter- and intra-annual variability, but not only the sum of annual precipitation is important
for the development of groundwater recharge; a large amount of precipitation in a relatively short period is more important.
Published independent data from the Kalahari in Namibia, Botswana and the Southern African region under similar climatic conditions
are used to verify the modelling results. 相似文献
4.
岱海湖为一内陆封闭型湖泊。本研究利用3、7、12月份冬夏工况,综合考虑岱海湖边界条件,水面温度、密度、水面天然温度、大气温度、相对湿度等影响因子,构建温排水对岱海湖附加蒸发量影响的计算公式。经计算,电厂温排水引起的岱海湖附加蒸发损失量为:3月份为39.46万m3,7月份为73.3万m3,12月份为10.6万m3,岱海湖电厂温排水年附加蒸发水量约为678.2万m3/a。结果表明:附加蒸发量与电厂温排水量变化一致。本研究对干旱区水资源利用具有重要意义。 相似文献
5.
From 1950s to 1980s, various observational studies around the globe found a significant decrease in surface solar radiation (SSR), which reversed in late 1980s for most of the countries including India. SSR observations at 12 stations located across India revealed that a much stronger dimming has reappeared during the last decade (2006–2015) after a brightening during 1996–2005. In the present study, effects of renewed solar dimming on actual evapotranspiration and runoff were analyzed using a semi-distributed hydrological model, Soil and Water Assessment Tool (SWAT) in 24 river basins (ranging from 1260 to 40000 km2) located in peninsular India. For these river basins, calibration (2003–2009) and validation (2010–2014) were performed using the observed daily discharge data, obtained from water resources information system (WRIS) of India, with a 3 year warm up period (2000–2002). The sequential uncertainty domain parameter fitting algorithm (SUFI-2) of SWAT-CUP (calibration and uncertainty program) was used with modified Nash–Sutcliffe efficiency (MNS) as the objective function to calibrate 13 model parameters, which can potentially affect streamflow. In nearly all the river basins, the p- and r-factor of 95 percentage prediction uncertainty (PPU) were more than 0.7 and less than 1, respectively. At daily timescale, MNS values were more than 0.5 in most of the river basins, reaching up to 0.66 and 0.71 during calibration and validation periods, respectively. Calibrated model was used to analyze the water balance of these river basins and different sets of experiments (with observed SSR trends) were performed to find SSR impacts on it. The model was simulated with and without the observed declines in SSR trends. The average change in SSR (in terms of evaporation equivalent) was −267.93 ± 100.92 mm/day/year (−5.62 ± 2.12%) with maximum reaching up to −417.12 mm/day/year (−8.99%). Due to this SSR change, actual evaporation was reduced resulting in 18.97 ± 9.78 mm/day/year (4.13 ± 2.50%) change in percolation. The percolation changes were higher for river basins having areas covered by forests and cropland/woodland, and having loam and sandy-clay soils. The increase in runoff generated was 6.90 ± 3.42 mm/day/year (2.14 ± 1.58%) with a maximum of 15.25 mm/day/year (7.56%) whereas corresponding increase in streamflow was found to be 9.93 ± 5.27 mm/day/year(4.21 ± 2.38%) with a maximum of 26.71 mm/day/year (11.86 %). The study reveals that the recent observed SSR changes are significant enough to have resulted in increased streamflow in the monsoon dominated tropical river basins of India. 相似文献
6.
The hydrological cycle, a fundamental component of climate is likely to be altered in important ways due to climate change.
In this study, the historical daily runoff has been simulated for the Chenab River basin up to Salal gauging site using a
simple conceptual snowmelt model (SNOWMOD). The model has been used to study the impact of plausible hypothetical scenarios
of temperature and rainfall on the melt characteristics and daily runoff of the Chenab River basin. The average value of increase
in snowmelt runoff for T + 1°C, T + 2°C and T + 3°C scenarios are obtained to be 10, 28 and 43%, respectively. Whereas, the average value of increase in total streamflow
runoff for T + 1°C, T + 2°C and T + 3°C are obtained to be 7, 19 and 28%, respectively. Changes in rainfall by −10 and + 10% vary the average annual snowmelt
runoff over the T + 2°C scenario by −1% and + 1% only. The result shows that melt is much more sensitive to increase in temperature than to
rainfall. 相似文献
7.
为了对非天然入湖径流过程的湖泊进行径流还原计算,以云南杞麓湖为例,分析并确立了湖泊径流还原的水量平衡模式,即同时考虑出流量、调离水量、工业、农业、生活用水以及蒸发水量的还原模式。同时还介绍了对现状入湖径流结果的一致性订正方法,并最终得到了杞麓湖天然入湖径流量。计算结果表明,所提出的方法具有一定的普遍性与适用性;且得到的结果可以为湖泊的径流调节提供近似天然状态下的径流系列。 相似文献
8.
Zhengmao Liu Xianguo Lu Sun Yonghe Chen Zhike Haitao Wu Yanbo Zhao 《Water Resources Management》2012,26(6):1455-1475
Naoli river basin(NRB), with an area of 24,863 km2, is the largest basin and also the largest marsh distribution area in Sanjiang Plain, Heilongjiang, China. The hydrological
evolution process of wetland in NRB has made a marked ecological responses for anthropic activities, also reflects the drying
trend of the Sanjiang Plain, Northeast China. Global climate warming also contributes to the hydrological evolution process.
The following key research results are obtained: (1) The monthly average water level of Naoli river at Caizuizi hydrological
station in different ages showed a marked decline tendency, the annual mean water level dropped from 96.63 m during 1960–1969
to 95.59 m during 2000–2005, the water level drawdown is 1.04 m; (2) The annual runoff flowing into wetlands in NRB decreased.
Duration of Naoli river and its tributaries being thoroughly frozen from riverbed to river-water-surface showed an prolonged
trend, and the water level drawdown in frozen seasons increased. The water storage capacities of wetlands in NRB declined.
(3) The interactions between ground water and surface water in wetland areas are close. The ground water level variation span
is bigger than that of surface water level in wetland areas of NRB. The drawdown of ground water level promotes the surface
water level to decline, correspondingly. In recent 20 years, the cultivated area extension of rice field in upstream NRB has
made an adverse influence on the hydrological processes of wetlands. (4) The wetland area decrease and farmland area increase
significantly contribute to the runoff depth decrease of wetlands in NRB. The runoff depth variability has been mostly posed
by anthropic activities. (5) Reservoirs, ditches and dykes in NRB have greatly changed the runoff generation processes. Thickness
of the seasonal frozen soil layer becoming thinner and the evaporation potential becoming bigger also contribute to the runoff
depth reduction and the water level drawdown of rivers. The present study results will provide a scientific basic for developing
an integrated watershed management program for NRB, especially, restoring the wetland hydrological processes, maintaining
or improving the wetland structure and enhancing the wetland service functions. 相似文献
9.
Aliakbar Nazari Samani Hassan Ahmadi Aliasghar Mohammadi Jamal Ghoddousi Ali Salajegheh Guy Boggs Razieh Pishyar 《Water Resources Management》2010,24(8):1531-1549
Gully erosion is one of the most complicated and destructive forms of water erosion. In order to prevent this erosion, the
important factors controlling gully heads must be understood. This paper examines gully head advancement in the Hableh Rood
Basin, Iran by (1) observing gully head advance between 1957 and 2005 using field studies, aerial photography and GIS analysis
and: (2) applying and evaluating widely used experimental models including the, Thompson (Trans ASAE 7(1):54–55, 1964), SCS (I) and SCS (II) models, for estimating migrating headcuts over the study period. The results showed that the highest
mean gully advancement (0.26 m year − 1) took place during the 1956–1967 period, with most gullies having lower and steady headcut retreat rates between 1967–2000
(0.21 m year − 1) and 2000–2005 (0.15 m year − 1). This suggests that the majority of gullies in the study area were still in the early stages of formation in the first study
period and their formation may be linked to land use or climatic changes pre 1956. Analysis of the correlation between environmental
characteristics of the study area and gully advancement indicated that the upslope area of head cuts and soluble mineral content
of the soil were the two most important factors influencing the spatial and temporal variation of gully longitudinal development.
Results of multiple regression revealed that the simple relation including upslope area and soluble minerals can explain 93%
of total variance and relatively reflects the effects of runoff and waterfall process for headcut retreat. Application of
statistical error analysis to evaluate the four gully advancement models showed that in comparison to other models, the second
model of SCS has more reliable results for predicting longitudinal gully advancement in this study area and other similar
regions. However, this study indicates that future modelling in the region should consider the role of soil soluble mineral
content in predicting gully advancement. 相似文献
10.
The Falling Lake Victoria Water Level: GRACE,TRIMM and CHAMP Satellite Analysis of the Lake Basin 总被引:2,自引:0,他引:2
Joseph L. Awange Mohammad A. Sharifi Godfrey Ogonda Jens Wickert Erik W. Grafarend Monica A. Omulo 《Water Resources Management》2008,22(7):775-796
In the last 5 years, Lake Victoria water level has seen a dramatic fall that has caused alarm to water resource managers.
Since the lake basin contributes about 20% of the lakes water in form of discharge, with 80% coming from direct rainfall,
this study undertook a satellite analysis of the entire lake basin in an attempt to establish the cause of the decline. Gravity
Recovery And Climate Experiment (GRACE), Tropical Rainfall Measuring Mission (TRMM) and CHAllenging Minisatellite Payload
(CHAMP) satellites were employed in the analysis. Using 45 months of data spanning a period of 4 years (2002–2006), GRACE
satellite data are used to analyse the variation of the geoid (equipotential surface approximating the mean sea level) triggered
by variation in the stored waters within the lake basin. TRMM Level 3 monthly data for the same period of time are used to
compute mean rainfall for a spatial coverage of .25°×.25° (25×25 km) and the rainfall trend over the same period analyzed.
To assess the effect of evaporation, 59 CHAMP satellite’s occultation for the period 2001 to 2006 are analyzed for tropopause
warming. GRACE results indicate an annual fall in the geoid by 1.574 mm/year during the study period 2002–2006. This fall
clearly demonstrates the basin losing water over these period. TRMM results on the other hand indicate the rainfall over the
basin (and directly over the lake) to have been stable during this period. The CHAMP satellite results indicate the tropopause
temperature to have fallen in 2002 by about 3.9 K and increased by 2.2 K in 2003 and remained above the 189.5 K value of 2002.
The tropopause heights have shown a steady increase from a height of 16.72 m in 2001 and has remained above this value reaching
a maximum of 17.59 km in 2005, an increase in height by 0.87 m. Though the basin discharge contributes only 20%, its decline
has contributed to the fall in the lake waters. Since rainfall over the period remained stable, and temperatures did not increase
drastically to cause massive evaporation, the remaining major contributor is the discharge from the expanded Owen Falls dam. 相似文献