The sand pile avalanche model simulates the occurrence of avalanches in sand and plots the frequency of these avalanches. With the increase of sand particles, the shape and size of sand pile are easy to model. But even though the shape of the pile is conical, a new grain of sand can also trigger avalanches. Some sand particles fall off the cone. And because these avalanches are unpredictable, it's impossible to predict whether the next grain of sand will lead to avalanches.

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.

Multi flow confluence algorithm model

Saltmod is a computer program used to predict soil moisture, salinity of groundwater and drainage, depth of groundwater table and drainage flow in irrigated farmland (hydrology), using different (GEO) hydrological conditions and their changing water management options, including groundwater irrigation and the use of some crop rotation schedules.