3.4.2 Monthly changes
Similar to the annual variation (Fig. S5), the monthly mean TLI( Σ )
values of both Shahe Reservoir and Chengxi Reservoir varied over a wide
range (41.80 ~ 48.85 and 39.20 ~ 45.35), whereas those of Huanglishu
Reservoir varied over a smaller range (43.43 ~ 47.35). The maximum
monthly mean TLI( Σ ) values generally occurred from August to October,
the minimum TLI( Σ ) values generally occurred from April to June, as
well as all three reservoirs showed a very clear upward trend from June
to August (summer months), probably due to the effect of temperature on
algae. This phenomenon indirectly confirms that temperature is one of
the causes that influence changes in the eutrophication of water bodies
(Herb and Stefan, 2003). Besides, through the comparison, it was found
that the TLI( Σ ) value of Chengxi Reservoir was lower than that of
Huanglishu Reservoir and Shahe Reservoir in all the months, and it can
also be concluded that the water quality of Chengxi Reservoir is better
than that of Huanglishu Reservoir and Shahe Reservoir.