Present article deals with the methods of measurement and observation of the solid deposited precipitation especially in the meteorological service. The insufficient predicative ability of these methods for the hydrological purposes is shown. The new instrument made in the IAP AS CR for the mass measurement of the solid deposited precipitation and icing at all is presented here. The results of instrumental measurement are compared with the routine synoptic observation. The instrument was tested at the meteorological observatory Milesovka and will be installed there to the routine operation. The setting of this instrument will lay the foundations of the measurement of the solid deposited precipitation by the objective way and of the appropriate data sets rise. It will make possible better evaluation of the solid precipitation deposit to hydrological inputs to a watershed. and Příspěvek se zabývá způsoby měření a pozorování pevných usazených srážek, především v meteorologické službě. Ukazuje na nedostatečnou vypovídající schopnost těchto způsobů měření pro hydrologické účely. Je zde představen nový přístroj vyrobený v ÚFA AV ČR, který měří hmotnost pevných usazených srážek a námrazků vůbec. Výsledky přístrojového měření jsou porovnány s klasickým synoptickým pozorováním. Přístroj byl testován na meteorologické observatoři Milešovka a bude zde nasazen do rutinního provozu. Nasazení přístroje položí základ pro objektivizaci měření pevných usazených srážek a vznik příslušných datových souborů. To umožní lepší hodnocení příspěvku pevných usazených srážek k hydrologickým vstupům do povodí.
Beiyun River Basin is holistically suffering a water shortage and relatively concentrated flood risk. The current operation (level-control) of dams and floodgates, which is in passive defense mode, cannot meet the demands of both flood control and storm water resources. An integrated flood forecasting and management system is developed by the connecting of the hydrological model and hydrodynamic model and coupling of the hydrodynamic model and hydraulic model for dams and floodgates. Based upon the forecasted runoff processes, a discharge-control operation mode of dams and floodgates is proposed to be utilized in order to well regulate the flood routing in channels. The simulated water level, discharge, and water storage volume under different design conditions of rainfall return periods and floodgates operation modes are compared. The results show that: (1) for small floods, current operation modes can satisfy the objectives, but discharge-control operation can do better; (2) for medium size floods, since pre-storing of the floods affects the discharge of follow-up floods by floodgates, the requirement of flood control cannot be satisfied under current operations, but the discharge-control operation can; (3) for large floods, neither operation can meet the requirement because of the limited storage of these dams. Then, the gravel pits, wetlands, ecological lakes and flood detention basins around the river must be used for excess flood waters. Using the flood forecasting and management system can change passive defense to active defense mode, solving the water resources problem of Beijing city and Beiyun River Basin to a certain extent.
Ponded infiltration experiment is a simple test used for in-situ determination of soil hydraulic properties, particularly saturated hydraulic conductivity and sorptivity. It is known that infiltration process in natural soils is strongly affected by presence of macropores, soil layering, initial and experimental conditions etc. As a result, infiltration record encompasses a complex of mutually compensating effects that are difficult to separate from each other. Determination of sorptivity and saturated hydraulic conductivity from such infiltration data is complicated. In the present study we use numerical simulation to examine the impact of selected experimental conditions and soil profile properties on the ponded infiltration experiment results, specifically in terms of the hydraulic conductivity and sorptivity evaluation. The effect of following factors was considered: depth of ponding, ring insertion depth, initial soil water content, presence of preferential pathways, hydraulic conductivity anisotropy, soil layering, surface layer retention capacity and hydraulic conductivity, and presence of soil pipes or stones under the infiltration ring. Results were compared with a large database of infiltration curves measured at the experimental site Liz (Bohemian Forest, Czech Republic). Reasonably good agreement between simulated and observed infiltration curves was achieved by combining several of factors tested. Moreover, the ring insertion effect was recognized as one of the major causes of uncertainty in the determination of soil hydraulic parameters.