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1.
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
2.
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
3.
Uncertainty Intercomparison of Different Hydrological Models in Simulating Extreme Flows 总被引:4,自引:0,他引:4
Xi Chen Tao Yang Xiaoyan Wang Chong-Yu Xu Zhongbo Yu 《Water Resources Management》2013,27(5):1393-1409
A growing number of investigations on uncertainty quantification for hydrological models have been widely reported in past years. However, limited studies are found on uncertainty assessment in simulating streamflow extremes so far. This article presents an intercomparison of uncertainty assessment of three different well-known hydrological models in simulating extreme streamflows using the approach of generalized likelihood uncertainty estimation (GLUE). Results indicate that: (1) The three modified hydrological models can reproduce daily streamflow series with acceptable accuracy. When the threshold value used to select behavioral parameter sets is 0.7, XAJ model generates the best GLUE estimates in simulating daily flows. However, the percentage of observations contained in the calculated 95 % confidence intervals (P-95CI) is low (<50 %) when simulating the high-flow index (Q10). (2) Decreasing average relative length (ARIL), P-95CI and increasing average asymmetry degree (AAD) are found, when the threshold value increases for both daily-flows and high-flows. However, there is a significant inconsistence between sensitivity of daily-flows and high-flows to various threshold values of the likelihood function. Uncertainty sources from parameter sets, model structure and inputs collectively accounts for above sensitivity. (3) The best hydrological model in simulating daily-flows is not identical under different threshold values. High P-95CIs of GLUE estimate for high-flows (Q10 and Q25) indicate that TOPMODEL generally performs best under different threshold values, while XAJ model produces the smallest ARIL under different threshold values. The results are expected to contribute toward knowledge improvement on uncertainty behaviors in simulating streamflow extremes by a variety of hydrological models. 相似文献
4.
Alba María Guadalupe Orellana González Rodrigo Máximo Sánchez-Román Marcos Vinicius Folegatti Cornélio Alberto Zolin 《Water Resources Management》2011,25(13):3371-3386
A dynamic systems simulation model of water resources was developed as a tool to help analyze alternatives to water resources
management for the Piracicaba, Capivari and Jundiaí River Water Basins (RB-PCJ), and used to run six 50-year simulations from
2004 to 2054. The model estimates water supply and demand, as well as contamination load by several consumers. Six runs were
performed using a constant mean precipitation value, changing water supply and demand and different volumes diverted from
RB-PCJ to RB-Alto Tietê. For the Business as Usual scenario, the Sustainability Index went from 0.44 in 2004 to 0.20 by 2054.
The Water Sustainability Index changed from 74% in 2004 to 131% by 2054. The Falkenmark Index changed from 1,403 m3 person − 1 year − 1 in 2004 to 734 m3 person − 1 year − 1 by 2054. We concluded that sanitation is one of the major problems for the PCJ River Basins. 相似文献
5.
Soil Erosion Assessment in a Hilly Catchment of North Eastern India Using USLE, GIS and Remote Sensing 总被引:9,自引:1,他引:8
In the present study, soil erosion assessment of Dikrong river basin of Arunachal Pradesh (India) was carried out. The river
basin was divided into 200 × 200 m grid cells. The Arc Info 7.2 GIS software and RS (ERDAS IMAGINE 8.4 image processing software)
provided spatial input data and the USLE was used to predict the spatial distribution of the average annual soil loss on grid
basis. The average rainfall erositivity factor (R) for Dikrong river basin was found to be 1,894.6 MJ mm ha−1 h−1 year−1. The soil erodibility factor (K) with a magnitude of 0.055 t ha h ha−1 MJ−1 mm−1 is the highest, with 0.039 t ha h ha−1 MJ−1 mm−1 is the least for the watershed. The highest and lowest value of slope length factor (LS) is 53.5 and 5.39 respectively for the watershed. The highest and lowest values of crop management factor (C) were found out to be 0.004 and 1.0 respectively for the watershed. The highest and lowest value of conservation factor (P) were found to be 1 and 0.28 respectively for the watershed. The average annual soil loss of the Dikrong river basin is 51 t
ha−1 year−1. About 25.61% of the watershed area is found out to be under slight erosion class. Areas covered by moderate, high, very
high, severe and very severe erosion potential zones are 26.51%, 17.87%, 13.74%, 2.39% and 13.88% respectively. Therefore,
these areas need immediate attention from soil conservation point of view. 相似文献
6.
Assessing Crop Water Demand by Remote Sensing and GIS for the Pontina Plain, Central Italy 总被引:1,自引:1,他引:0
Raffaele Casa Matteo Rossi Giuseppe Sappa Antonio Trotta 《Water Resources Management》2009,23(9):1685-1712
An estimation of the crop water requirements for the Pontina Plain, Central Italy, was carried out through the use of remote
sensing land classification and application of a simple water balance scheme in a GIS environment. The overall crop water
demand for the 700 km2 area was estimated at about 70 Mm3 year − 1, i.e. 100 Mm3 year − 1 irrigation requirements when considering an average irrigation application efficiency of 70%. The simplest and least demanding
available methodology, in terms of data and resources, was chosen. The methodology, based on remote sensing and GIS, employed
only 4 Landsat ETM+ images and a few meteorological and geographical vectorial layers. The procedure allowed the elaboration
of monthly maps of crop evapotranspiration. The application of a spatially distributed simple water balance model, lead to
the estimation of temporal and spatial variation of crop water requirements in the study area. This study contributes to fill
a gap in the knowledge on agricultural use of water resources in the area, which is essential for the implementation of a
sustainable and sound water policy as required in the region for the application of the EU Water Framework Directive. 相似文献
7.
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
8.
Predictive Simulation of Flow and Solute Transport for Managing the Salalah Coastal Aquifer, Oman 总被引:1,自引:1,他引:0
A three-dimensional numerical model for flow and solute transport was used for the management of the Salalah aquifer. The
model calibration procedures consisted of calibrating the aquifer system hydraulic parameters by history matching under steady
and transient conditions. The history of input and output of the aquifer were reconstructed in a transient calibration from
1993 to 2005. Predictive simulation of the aquifer was carried out under transient conditions to predict the future demand
of groundwater supply for the next 15 years. A baseline scenario was worked out to obtain the piezometric surface and salinity
distribution for the “business as usual” conditions of the aquifer. The “business as usual” scenario was predicted and simulated
for the period 2006 until 2020. The effectiveness of seven management options was proposed and assessed for comparison with
the “business as usual” conditions. The established simulation model was used to predict the distribution of the piezometric
surface, salinity distribution, and mass balance under the proposed scenarios for the prediction period 2006–2020. The scenarios
were: (1) relocate Garziz and MAF farms far from the freshwater zone, (2) suspend the abstraction of grass production for
4 months a year, (3) changes in agricultural and irrigation system patterns, (4) establish a desalination plant, (5) combined
scenario (1 + 4), (6) combined scenario (1 + 3), and (7) combining all scenarios (1 + 2 + 3 + 4). The result of the simulation
shows that the best effective option in terms of aquifer groundwater levels is the fifth proposed scenario and the sixth proposed
scenario is the best effective option in terms of aquifer groundwater salinity situation during the next 15 years. This project
suggested the application of scenario 6 as it is environmentally sound in terms of sustainable management. A prediction has
been made which shows that further actions have to be taken within the next two decades to ensure continuity of the municipal
water supply. The management scenarios are examined in the case of the Salalah coastal aquifer using groundwater simulation,
which can also be applied to other regions with similar conditions. The established model is considered a reasonable representation
of the physical conditions of the Salalah plain aquifer, and can be used as a tool by the water and environmental authorities
in the management of the groundwater in the region. 相似文献
9.
Estimations of Evapotranspiration and Water Balance with Uncertainty over the Yukon River Basin 总被引:2,自引:1,他引:1
Wenping Yuan Shuguang Liu Shunlin Liang Zhengxi Tan Heping Liu Claudia Young 《Water Resources Management》2012,26(8):2147-2157
In this study, the revised Remote Sensing-Penman Monteith model (RS-PM) was used to scale up evapotranspiration (ET) over
the entire Yukon River Basin (YRB) from three eddy covariance (EC) towers covering major vegetation types. We determined model
parameters and uncertainty using a Bayesian-based method in the three EC sites. The 95 % confidence interval for the aggregate
ecosystem ET ranged from 233 to 396 mm yr−1 with an average of 319 mm yr−1. The mean difference between precipitation and evapotranspiration (W) was 171 mm yr−1 with a 95 % confidence interval of 94–257 mm yr−1. The YRB region showed a slight increasing trend in annual precipitation for the 1982–2009 time period, while ET showed a
significant increasing trend of 6.6 mm decade−1. As a whole, annual W showed a drying trend over YRB region. 相似文献
10.
Influence of Scale on SWAT Model Calibration for Streamflow in a River Basin in the Humid Tropics 总被引:3,自引:1,他引:2
The Soil Water Assessment Tool (SWAT) was applied to the 2,530 km2 Chaliyar river basin in Kerala, India to investigate the influence of scale on the model parameters. The study was carried
out in this river basin at two scales. Parameters such as land use, soil type, topography and management practices are similar
at these scales. The model was initially calibrated for streamflow and then validated. Critical parameters were the curve
number (CN2), soil evaporation compensation factor (ESCO), available water holding capacity (SOL_AWC), average slope length
(SLSUBBSN), and base flow alpha factor (ALPHA_BF). Using the optimized value of various parameters, stream flow was estimated
from parts of the basin at two different scales—an area of 2,361.58 km2 and an area of 1,013.15 km2. The streamflow estimates at both these scales were statistically analysed by computing the coefficient of determination
(R
2) and the Nash–Sutcliffe efficiency (ENS). Results indicate that the SWAT model could simulate streamflow at both scales reasonably well with very little difference
between the observed and computed values. However, the results also indicate that there may be greater uncertainty in SWAT
streamflow estimates as the size of the watershed increases. 相似文献