A two-year field study and evaluation of water quality and trophic state of a large shallow drinking water reservoir in Shanghai, China

Abstract

A B S T R A C TReservoirs have been widely constructed all over the world in recent years to alleviate the shortage of water resources. Nevertheless, the assessment method of water quality and its trophic status needs to be developed. In this study, water quality parameters of a newly constructed shallow reservoir were regularly monitored for a period of two years, which is used as a major drinking water source of Shanghai, China. Furthermore, the trophic state indices of the reservoir were investigated based on literature and evaluated with the two-year field data. The results indicated that the studied reservoir is reaching the mesotrophic-eutrophic boundary, where further nutrient enrichment could cause water quality degradation; total phosphorus is the limiting nutrient for algal growth in the studied reservoir. Results of the study can help operators understand change and status of water quality of the reservoir and provide valuable data demonstrating variation of water quality indicators and trophic characteristics in shallow reservoirs or lakes.

Driving Factors and Dynamics of Phytoplankton Community and Functional Groups in an Estuary Reservoir in the Yangtze River, China

“…The current results (9 < TN/TP < 26) confirmed that there were no obvious nutrient limitation tendencies for phytoplankton growth in the reservoir ( Figure S3). However, a previous study suggested that the reservoir is P limited [26]. Compared to that study, TP in the current study was much higher.…”

“…The ratio between the euphotic and mixing depths (Zeu/Zmix) was used as a measure of light availability [35]. Trophic state index (TSI) values were calculated based on the method described in the study of Liu et al [26]. For main nutrient seasonal variation in each section, sampling sites were taken for replicates as follows: S1 and S12 for estuary, S2 and S3 for upstream, S4 to S6 for midstream, S7 to S11 for downstream.…”

“…Seasonal and spatial changes of environmental variables play an important role in determining physical and chemical conditions, which affect phytoplankton dynamics in this estuary reservoir. Previous study showed that the reservoir was less eutrophic during the construction period in 2009 with highest TSI value of 51 and changed to a mesotrophic state TSI during the trial operation period in 2010 [26,40]. It seems that the eutrophic state became better established during the full operation period in 2014.…”

“…Because of excessive nutrient loading and its shallowness with a long hydraulic retention time (approximately 25 days) the reservoir still faces the threat of eutrophication issues, such as cyanobacterial blooms. Previously, results of a two year study indicated that the reservoir is reaching the mesotrophic-eutrophic boundary, where further nutrient enrichment could cause water quality degradation [26]. A microbial community study showed high cyanobacteria biomasses occurred during summer seasons [27].…”

Nitrogen and phosphorus in cascade multi-system tropical reservoirs: water and sediment

“…Increases in water demand, as well as in water pollution in some countries, have led to the construction of reservoirs to ensure water quality and availability, especially in highly urbanized regions (Lehner et al 2011;Liu et al 2016). In South America, economic development is resulting in increased requirements for water storage and energy production.…”