Drainage basin downstream water level prediction method

The invention relates to a drainage basin downstream water level prediction method, which comprises the following steps of: constructing upstream water level lag characteristics by adopting a method of gradually moving upstream water level characteristics backwards for a plurality of time units and keeping downstream water level data unchanged based on the upstream water level characteristics; correlation coefficient calculation is carried out on the upstream water level data and downstream water level data, and upstream water level lag features with correlation coefficients higher than a set value are taken to form an upstream water level lag feature set; forming a preliminary model feature set by the upstream water level lag feature set, the rainfall feature, the flood discharge feature, the upstream water level feature and the downstream water level data; carrying out feature screening on the preliminary model feature set by adopting lasso to obtain a model feature set after feature screening; training and