Establishment of model
Take the river water quality model as an example. The mathematical model of river water quality is to describe the internal laws and relationships of physics, chemistry, biology and ecology in the process of river water pollution with mathematical language and methods, that is, to transform a complex river system into a set of suitable mathematical equations for mathematical simulation. Basic equation of river water quality model
Steps of establishing water quality model:
(1) Collect and analyze data and information related to modeling, and make preparations for modeling.
(2) According to the obtained information and data, select appropriate model variables, determine the mutual influence and change law between variables, write the best structural form of mathematical equations describing these relationships, and reflect the basic characteristics of describing phenomena.
(3) Some parameters in the model equation need to be determined in some way, such as empirical formula, indoor experiment or mathematical method. However, when determining the parameters, it is necessary to make the obtained values pay more attention to the observation data after being substituted into the model.
(4) After the water quality model is established, it is necessary to test whether the model structure is effective and predictive.
Classification method
There are many classification methods of water quality models, which can be divided into dissolved oxygen (DO) model, biochemical oxygen demand (BOD) model, heavy metal model and radioactive model. Biochemical oxygen demand (BOD) and dissolved oxygen (DO) are the two most important water quality indicators, which are often used as the basis for establishing organic water quality models.