Delft3D is a powerful software package developed by WL Delft hydraulics of Delft University in the Netherlands, which is mainly used in free surface water environment. The software has a flexible framework, which can simulate two-dimensional and three-dimensional flow, wave, water quality, ecology, sediment transport and bed topography, as well as the interaction among various processes. It is one of the most advanced hydrodynamic water quality models in the world. Delft3D system is widely used in the world, such as the Netherlands, Poland, Germany, Australia, the United States and so on, especially the United States has a long history of application. The Delft3D system has been used in Hong Kong since the mid-1970s and has become a standard product of the Hong Kong Environment Agency. Delft3D has been applied more and more in mainland China since the mid 80s, such as Changjiang Estuary, Hangzhou Bay, Bohai Bay, Taihu and Dianchi. Delft3D is the most advanced and complete 3D hydrodynamic water quality model system in the world, especially the unique support surface format.

Multi flow confluence algorithm model

Ecohat system is based on the study of eco hydrological process mechanism, starting from the basic water cycle process, adding nutrient migration and transformation process in the water cycle process, comprehensively considering the interaction of vegetation / biological growth, water cycle elements and nutrients in land water ecosystem. The ecohat system model is built on the basis of integrating the advantages of eco hydrological process models with physical and chemical mechanisms at home and abroad. After model adjustment, the model adopts parameters suitable for China's natural conditions to establish a localized database. Ecohat system realizes pixel based model operation by inputting regional spatial grid parameters. Therefore, ecohat system is a completely distributed integrated simulation system of eco hydrological process. Ecohat system includes four parts: water cycle, nutrient cycle, plant growth and aquatic environment response. Water cycle is the core of the system and runs through the other three parts. The simulation of water cycle in ecohat system includes five processes: rainfall infiltration, surface runoff, evapotranspiration, root water absorption and soil moisture; nutrient cycle mainly includes the simulation of nitrification, denitrification and ammonia volatilization in soil, the simulation of base cation cycle in soil, and the quantitative simulation of adsorbed phosphorus produced by soil erosion process; plant growth It includes vegetation ecological water use simulation, vegetation NPP (net primary productivity) simulation, productivity distribution process simulation and vegetation nutrient element absorption simulation.

Elm is mainly used to develop and share a better understanding of biological, chemical and hydrological interactions in landscape mosaic ecosystems. In the field of ecology, models can help organize or integrate our understanding of system ecology. This understanding can be applied to assess the relative benefits of simulation scenarios that will change in the future.

Algorithm model of continuous multi flow confluence

IHACRES model is a lumped conceptual rainfall runoff model based on unit hydrograph principle. It is composed of two basic modules in series: in the nonlinear module, rainfall is transformed into effective rainfall; in the linear module, effective rainfall is further transformed into runoff. The model is suitable for a series of spatial and temporal scales.