Advanced Materials Research Vols. 726-731

Abstract: Snow melting is an important process of snow hydrology. A process-based energy balance snowmelt model: Snow Column Model is developed to reveal the processes of energy conservation, phase change, mass transfer, compaction and growth of grain size. It could provide the information of snow density, temperature and liquid water held in snow packs varied with snowmelt processes. The observations during April and June, 1996 of snowpit in Niwot Ridge, Colorado, Front Range of Rocky Mountains are used to calculate and compare. The calculated ones are consistent with the observed. The model not only demonstrates the processes happened inside snow pack, but also will offer a better understanding of the response of snow pack to climate change in further studies.

Abstract: Based on the process-based energy balance snow melting model Snow Column Model, several scenarios are set to study the response of snow pack to climate change according to site-based data in snowpit 006, Niwot Ridge, Colorado, Front Range of Rocky Mountains. Based on an introduction and validation of Snow Column Model by data of 1996, a further validation is made on data during 1997 and 1999. Scenarios are set based on observations of solar radiation, long-wave radiation, air temperature, latent and sensible heat flux during 1996 and 1999. The responses of snow pack to an average temperature fluctuation within 6.2°C are analyzed. The results illustrate that snow density and snow water equivalent accelerated decreases while the variance in snow density does not increase monotonically over time.

Abstract: Three gorges hydropower, the biggest hydropower project in the world at present, is a backbone project for flood control and water power development of Yangtze river. From the flood season in 2008 with the beginning test impounding to 2012 has been implemented for five years, that water level has been continue to rise to 175m during 2010 to 2012. After the impoundment to normal water level, backwater is near Jiangjin during dry season with water level of 175m and is nearby Changshou in flood with water level of 145m, then Changshou upstream is the fluctuating backwater region. In this paper, based on a large amount of measured hydrologic data with Zhutuo, Cuntan, Qingxichang and Beibei, Wulong hydrological station on fluctuating backwater region, firstly suspended sediment inflow changes is analyzed, secondly suspended sediment characteristics is studied from the grouping sediment content and gradation change along the river in experimental impounding, then suspended sediment basic characteristics is gained about varying backwater region.

Abstract: t is important to reasonably raise the reservoir flood limited water level in order to increase the utilization of the rainwater resources. The methods to set the flood limited water level include the static control and the dynamic control. And the dynamic control methods include the multiple duration method and the dynamic control method. All those methods were summarized and analyzed in this paper, especially the dynamic control. The advantages of the multiple duration method and the dynamic control method for the flood were indicated respectively. Those two methods were contrastively analyzed from the design principles, the application conditions, the actual operation complexity and the risk control factors. Then the conclusion was obtained, that the dynamic control method will be more advantageous and popular than the multiple duration the in the future.

Abstract: This paper analyzes the status quo and the existing problems of water resources in Zhejiang Province. Although with an abundant total quantity, the per capital hold of water resources here is low. Besides, this area is characterized by an uneven annual and inter-annual distribution of water resources, with frequent droughts and floods. The uneven regional distribution causes incompatible socio and economic development, and the low utilization of water resources leads to serious water pollution. In order to solve the existing problems and insure water security, the government proposed countermeasures which mainly cover the following items:first, to enhance the efficiency of water use and resolve contradictions between water supply and the demand; second, to promote rational development of water resources and strengthen comprehensive utilization; third, to raise the awareness of water security and promote innovations on the scientific management of water resources;fourth, to improve related mechanisms on water price and accelerate the pace of water rights trading.

Abstract: Mass concrete ,such as dam concrete will appear vertical and horizon cracks due to various reasons. and these cracks will threat the safe operation and limit the economic benefits of the dam. pre-stressed anchor cables have been widely used as a main reinforcement method. the paper focuses on the cable construction technique and describes its effective reinforcement capabilities combined with the reinforcement of Panjiakou dam.The horizontal crack of Panjiakou concrete gravity dam is an activity crack, which varies with season and temperature change. Results of many years of test and research showed that the application of "combining caulking with draining and pre-stressed Anchorage" in the treatment of the crack was effective.At present, reinforcement construction has been completed, and the project operates well.

Abstract: Water blooms occurred in Xinlicheng reservoir in 2007 and eutrophication was paid attention on. The method of comprehensive eutrophication state index was adopted to assess eutrophication state and change of TN, TP, COD_Mn and pH were analyzed based on water quality monitoring data of Xinlicheng reservoir from 2000 to 2010. From 2003 to 2007, degree of eutrphication changed from mesotrophication to light eutrohpication. Eutrophication of Xinlicheng reservoir was caused by the pollution of nitrogen and phosphorus and the pollutant sources include extraneous and endogenous sources. Extraneous sources come from upstream water and periphery of the reservoir, while endogenous sources come from sediments. Ecological wetland should be constructed in estuarine area, fish and bivalves should be put into the reservoir and other comprehensive measures should be taken to control nitrogen, phosphorous and algae. Obvious effect has been achieved by eutrophication treatment measures.

Abstract: Based on the systematical analysis of hydrogeology, social economy and regional environment, choosing 23 indicators from four aspects of the groundwater resources condition, social economy, the ecological environment, Sustainability assessment system of groundwater resources for southwestern karst mountain area were established. Meanwhile, the weights of the indicators based on AHP were determined, which can reduce the fuzziness of man-made judgments. the sustainability of groundwater resources were evaluated and had a much better result by referring to the Weining area of Guizhou province. Thus, provide certain references for similar regional assessment.

Abstract: In this study, the Tropical Rainfall Measuring Mission (TRMM) version 7 satellite rainfall product, TRMM 3B42 (V7), was validated using rain gauge measurements in the Upper Huaihe Basin, China. This validation was carried out at monthly and annual temporal scales for an 11-year period using four selected grids with six, four, two and one rain gauge station (s) located within the TRMM grid respectively; the rain gage measurements for grids with more than one rain gauge were averaged. This study found that the validation of the TRMM dataset in grids where there were adequate rain gauge were present to capture the distributed and stochastic nature of rainfall with very good correlation (0.87-0.94) and with very little relative bias when the rain gage accumulations were compared with the TRMM estimates. From the study we found that the TRMM dataset can be used as precipitation input for hydrological modeling at monthly and annual scales for sustainable water resources management in the Upper Huaihe River and even in un-gaged or sparsely gaged basins in other parts of the world.

Abstract: Mesoscale Convective Systems (MCSs) contain both regions of convective and stratiform precipitation, and a bright band (BB) or equivalent high-reflectivity region is often found in the stratiform precipitation. Inflated reflectivity intensities in the BB often cause positive biases in radar quantitative precipitation estimation (QPE), and a vertical profile of reflectivity (VPR) correction is necessary to reduce the error. VPR corrections of the radar QPE is more difficult for MCSs than for a widespread cool season stratiform precipitation because of the spatial non-homogeneity of MCSs. Further, microphysical processes in the MCS stratiform region are more complicated than in the large-scale cool season stratiform precipitation. A clearly defined BB bottom, which is critical for accurate VPR corrections, is often not found in ground radar VPRs from MCSs. This is a big challenge when the stratiform region of MCSs is far away from the radar where the radar beam is too high or too wide to resolve the BB bottom. Further, variations of reflectivity below the freezing level are much more significant in MCSs than in a large-scale cool season precipitation, requiring high-resolution radar observations near the ground for an effective VPR correction. The current study seeks to use the vertical precipitation structure observed from Tropical Rainfall Measuring Mission Precipitation Radar (TRMM PR) to aid VPR corrections of the ground radar QPE in MCSs. High-resolution VPRs are derived from TRMM data for MCSs and then applied for the correction of ground radar QPEs.