Showing papers by "Lu Zhang published in 2006"
TL;DR: In this paper, the authors measured the hydrological sensitivity, measured as the percentage change in mean annual runoff, of two lumped parameter rainfall-runoff models, SIMHYD and AWBM and an empirical model, Zhang01, to changes in rainfall and potential evaporation.
242 citations
TL;DR: In this paper, the authors address the water security issues facing North China in the 21st century using the Hai River basin as an example, and describe hydrologic cycles under changing environments, water-saving agriculture, assessment of water resource security, and efforts towards achieving integrated catchment management.
Abstract: Water shortages and related environmental degradation in North China are major issues facing the country. As runoff from the mountainous parts of the region steadily decrease and water resources become overcommitted, serious water and environmental problems have resulted. These include drying-up of rivers, decline in groundwater levels, degradation of lakes and wetlands, and water pollution. Thus, 4000,km of the lower reaches of the Hai River – some 40% of its length – has experienced zero flows and, as result, parts of this river have become an ephemeral stream. The area of wetland within the Basin has decreased from 10,000,km2 at the beginning of 1950s to 1,000km2 at present. Over-extraction of groundwater occurs beneath 70% of the North China Plain, with the total groundwater over-extraction estimated at 90,billion m3. Thus, problems of water shortage and related environmental issues in North China have become the most significant limiting factors affecting sustainable development in this important region of China. This paper addresses the water security issues facing North China in the 21st Century using the Hai River basin as an example. We describe hydrologic cycles under changing environments, water-saving agriculture, assessment of water resource security, and efforts towards achieving integrated catchment management.
123 citations
TL;DR: In this paper, a model was developed to estimate the seasonality effect on catchment-scale mean annual water balance using a top-down approach based on observed rainfall, potential evapotranspiration and streamflow data from 326 unregulated catchments in Australia.
73 citations
TL;DR: In this article, a 2D model of root water uptake for single apple trees and validation of the model with sap flow and soil water content measurements in an orchard was presented, which showed an excellent agreement between the measured data and the simulated outputs.
59 citations
TL;DR: In this paper, an alternative approach, described in this paper, is to estimate the extractable soil moisture capacity from direct measurements of soil moisture content in the field, using a time series of water values, over the depth of the soil, shows the actual changes in water content.
Abstract: The amount of water that can be stored in soil and evaporated or actively used by plants is a key parameter in hydrologic models and is important for crop and pasture production. Often, the active soil moisture store is estimated from laboratory measurements of soil properties. An alternative approach, described in this paper, is to estimate the extractable soil moisture capacity from direct measurements of soil moisture content in the field. A time series of soil moisture values, over the depth of the soil, shows the actual changes in water content. The difference between the wettest and driest profiles is an estimate of the extractable soil moisture storage. We have gathered data on extractable soil water capacity for 180 locations over Australia and have compared our values with published results from the Atlas of Australian Soils (AAS), derived from profile descriptions and pedo-transfer functions. Our results show that data from the AAS provide a useful lower bound for measured extractable soil moisture storage, but of the sites examined, 42% had values >2 times those in the AAS. In part, this was because total soil depths were underestimated in the AAS results compared with the active depths from the measured data. Active depths are strongly related to vegetation type.
7 citations