With the continuous progress of society, online water quality monitoring is all too common around us. In this chapter, the editor will explore the issues related to the design of water quality monitoring sections and sampling points together with everyone.

May I ask what the design principles of the monitoring section are?

Monitoring sections are set up at functional areas where water quality changes and for different uses of water bodies:

A large amount of sewage is discharged into the upstream and downstream areas of residential and industrial zones along rivers.

2) The main entrances and exits of lakes and reservoirs;

3) Drinking water source area;

4) The estuaries of rivers flowing into the sea, the upper reaches of the confluence of larger tributaries, and the areas where they converge and mix with the main stream;

Determine the sampling time and the sampling evaluation rate

1) Sampling and monitoring of drinking water sources are conducted 12 times throughout the year, and the sampling time is determined based on specific circumstances.

2) For the main streams of larger water systems and medium and small rivers, the number of sampling and monitoring sessions throughout the year should be no less than six times. The sampling times are the wet season, the dry season and the normal season, with sampling twice in each period.

3) For rivers flowing through cities or industrial zones with heavy pollution and tourist waters, sampling and monitoring should be conducted no less than 12 times throughout the year. The sampling time is once a month or selected based on specific circumstances.

The problem of sample point layout in places such as lakes and reservoirs.

Different lakes and reservoirs should be treated differently. Therefore, it is necessary to first determine the number of lakes and rivers, the runoff volume of water bodies, the dynamic changes of seasonal variations, the distribution of pollution sources along the banks, the diffusion and self-purification laws of pollutants, and the characteristics of the ecological environment, etc. Then determine the location of the monitoring section according to the setting principles mentioned earlier!

1) Monitoring sections shall be set up respectively at the confluence of rivers flowing into and out of lakes and reservoirs.

2) Monitoring sections are arc-shaped set up along the radiation lines of each functional area as the center.

3) Monitoring sections should be set up in the center of lakes and reservoirs, deep and shallow water areas, stagnant water areas, spawning areas for different fish species, and aquatic biological economic zones.