The UNMIX model is a mathematical receptor model developed by scientists from the U.S. Environmental Protection Agency. It provides scientific support for the development and review of air and water quality standards, exposure studies and environmental forensics. UNMIX can analyze a wide range of environmental sample data: sediment, wet deposition, surface water, ambient air and indoor air.

Glims model is jointly developed by University of Georgia and USDA-ARS, its predecessor is creams, which is mainly used for small-scale simulation. The water quality items that can be simulated include sediment, nitrate nitrogen, ammonia nitrogen, phosphorus nitrate, ammonia nitrogen, total nitrogen, total phosphorus, etc. The modified SCS curve number method was used to simulate rainfall runoff, and the priestly Taylor or penman Monteith method was used to simulate evaporation. By simulating the effects of ammoniation, nitrification, denitrification, volatilization, absorption and fixation, the nitrogen factor was simulated by combining empirical or semi empirical formula with the model. A long-term soil erosion model developed by Sharpley et al. Was used to simulate phosphorus. The pesticide composition was mainly aimed at the interaction of pesticide characteristics, soil texture, climate impact, management strategy, surface runoff leakage and adhesion. The model also simulated the pesticide transport in the rhizosphere.

ALMANAC model is a practical model, which was first used as a part of EPIC model to simulate the decline of land productivity caused by soil erosion. ALMANAC model can simulate crop growth process and soil water balance process, including: light interception by crop leaves, biomass accumulation, biomass distribution in different organs of crops, full utilization of water by crops, absorption of nutrients, and constraints of environmental factors on crop growth process, such as water stress, temperature stress and nutrient stress. The ALMANAC model provides a util editor. This is a very friendly interface database editing program, can directly provide users with the input variable database prompt operation.

Integrated water flow model is a computer program used to simulate the flow of land surface, surface water and groundwater. It is a rewrite of IGSM software. Iwfm program and source code are provided free of charge. It uses finite element method to simulate groundwater flow. Surface water flow can be simulated by a simple one-dimensional flow network or by moving wave method. Allows users to run models for a specific period of time while editing input files. Iwfm simulates four land use categories: agriculture, urban, native vegetation and riparian vegetation. Land use area is divided into a time series with corresponding evapotranspiration rate and water management parameters. In the agricultural and urban land use categories, iwfm applies surface water and groundwater according to a specific ratio, and can selectively adjust surface water and groundwater to meet water demand.

Algorithm model of continuous multi flow confluence