Table 2.

Summary of cluster analysis results of NH₃-N in each catchment

Serial number	Abbreviation of catchments	Category	Name of the catchment
Group.1	Z1, Z6, Z2	Entire qualified class	Jintan, Taerqiao, Zhamalong
Group.2	Z7, Z8, Z13	Basic compliance class	Xinningqiao-Datong, Runzeqiao, Minheqiao
Group.3	Z9	Sectional excess class	Chaoyangqiao
Group.4	Z11	Sectional excess class	Shatangchuanqiao
Group.5	Z10	Sectional excess class	Sanqiqiao
Group.6	Z4, Z5	Basic excess class	Wanziqiao, Laoyaxiakou
Group.7	Z3	Sectional excess class	Xiaoxiaqiao
Group.8	Z12	Sectional excess class	Qiyiqiao