Long-term analysis of road salt loading and transport in a rural drinking water reservoir watershed

Forty years record of the metalimnetic oxygen minimum in Germany’s largest drinking water reservoir

10.5194/egusphere-egu21-12937 ◽

2021 ◽

Author(s):

Michael Seewald ◽

Chenxi Mi ◽

Jan Donner ◽

Karsten Rinke

Keyword(s):

Drinking Water ◽

Water Quality Management ◽

Water Reservoir ◽

Oxygen Depletion ◽

Oxygen Deficit ◽

Drinking Water Reservoir ◽

Lakes And Reservoirs ◽

Low Levels ◽

Oxygen Minimum

<p>Dissolved oxygen is a central player in water quality management of lakes and reservoirs. Low levels or absence of oxygen poses a major problem, especially in drinking water reservoirs. Usually, the focus lies on the oxygen depletion in deep water. However, in many stably stratified water bodies, significant oxygen deficits have been documented in the metalimnion, even in lakes of low trophic state. This phenomenon is known as metalimnetic oxygen minimum (MOM) and the causes of MOM have been discussed controversially. The Rappbode Dam, Germany's largest drinking water reservoir, forms a MOM every year and long-term observations indicate that the oxygen deficit may have increased in recent years. Although the data cover a long period (40 years), they are very heterogeneous in terms of temporal and spatial resolution. Our study aims at systematically analysing the available data to characterize the interannual development of the MOM with respect to existing trends and to identify relevant environmental and management factors. The results confirm increasing surfacewater temperatures and unchanged deepwater temperatures in summer (Mai to October) as well as an increasingly prolonged summer stratification in the course of global warming. In contrast to the previous working hypothesis, increasing stratification duration is not correlated with the significantly increasing (p 0.009; &#964; -0.26) annual maximum intensity of the MOM.</p>

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Seasonal Water Quality and Algal Responses to Monsoon-Mediated Nutrient Enrichment, Flow Regime, Drought, and Flood in a Drinking Water Reservoir

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph182010714 ◽

2021 ◽

Vol 18 (20) ◽

pp. 10714

Author(s):

Md Mamun ◽

Usman Atique ◽

Ji Yoon Kim ◽

Kwang-Guk An

Keyword(s):

Water Quality ◽

Drinking Water ◽

Flow Regime ◽

Nutrient Enrichment ◽

Water Reservoir ◽

Reservoir Water ◽

Chl A ◽

Drought And Flood ◽

Drinking Water Reservoir

Freshwater reservoirs are a crucial source of urban drinking water worldwide; thus, long-term evaluations of critical water quality determinants are essential. We conducted this study in a large drinking water reservoir for 11 years (2010–2020). The variabilities of ambient nutrients and total suspended solids (TSS) throughout the seasonal monsoon-mediated flow regime influenced algal chlorophyll (Chl-a) levels. The study determined the role of the monsoon-mediated flow regime on reservoir water chemistry. The reservoir conditions were mesotrophic to eutrophic based on nitrogen (N) and phosphorus (P) concentrations. An occasional total coliform bacteria (TCB) count of 16,000 MPN per 100 mL was recorded in the reservoir, presenting a significant risk of waterborne diseases among children. A Mann–Kendall test identified a consistent increase in water temperature, conductivity, and chemical oxygen demand (COD) over the study period, limiting a sustainable water supply. The drought and flood regime mediated by the monsoon resulted in large heterogeneities in Chl-a, TCB, TSS, and nutrients (N, P), indicating its role as a key regulator of the ecological functioning of the reservoir. The ambient N:P ratio is a reliable predictor of sestonic Chl-a productivity, and the reservoir was P-limited. Total phosphorus (TP) had a strong negative correlation (R2 = 0.59, p < 0.05) with the outflow from the dam, while both the TSS (R2 = 0.50) and Chl-a (R2 = 0.32, p < 0.05) had a strong positive correlation with the outflow. A seasonal trophic state index revealed oligo-mesotrophic conditions, indicating a limited risk of eutrophication and a positive outcome for long-term management. In conclusion, the Asian monsoon largely controlled the flood and drought conditions and manipulated the flow regime. Exceedingly intensive crop farming in the basin may lead to oligotrophic nutrient enrichment. Although the reservoir water quality was good, we strongly recommend stringent action to alleviate sewage, nutrient, and pollutant inflows to the reservoir.

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Long-term trend of heat waves and potential effects on phytoplankton blooms in Lake Qiandaohu, a key drinking water reservoir

Environmental Science and Pollution Research ◽

10.1007/s11356-021-15414-z ◽

2021 ◽

Author(s):

Qunfang Huang ◽

Na Li ◽

Yuan Li

Keyword(s):

Drinking Water ◽

Heat Waves ◽

Water Reservoir ◽

Phytoplankton Blooms ◽

Term Trend ◽

Drinking Water Reservoir ◽

Long Term Trend

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Long-Term Trends in the Nutrient Input and In-Lake Concentrations of a Drinking Water Reservoir in a Dense Populated Catchment Area (Erzgebirge, Germany)

Internationale Revue der gesamten Hydrobiologie und Hydrographie ◽

10.1002/iroh.19940790206 ◽

1994 ◽

Vol 79 (2) ◽

pp. 213-227 ◽

Cited By ~ 8

Author(s):

W. Horn ◽

H. Horn ◽

L. Paul

Keyword(s):

Drinking Water ◽

Catchment Area ◽

Water Reservoir ◽

Nutrient Input ◽

Drinking Water Reservoir ◽

Long Term Trends

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Long-term improvement in surface water quality after land consolidation in a drinking water reservoir catchment

Soil and Water Research ◽

10.17221/108/2013-swr ◽

2016 ◽

Vol 10 (No. 1) ◽

pp. 49-55 ◽

Cited By ~ 1

Author(s):

M. Dumbrovský ◽

V. Sobotková ◽

B. Šarapatka ◽

R. Váchalová ◽

R. Pavelková Chmelová ◽

...

Keyword(s):

Water Quality ◽

Drinking Water ◽

Surface Water ◽

Water Reservoir ◽

Surface Water Quality ◽

Land Consolidation ◽

Drinking Water Reservoir

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Long-Term Interannual and Seasonal Links between the Nutrient Regime, Sestonic Chlorophyll and Dominant Bluegreen Algae under the Varying Intensity of Monsoon Precipitation in a Drinking Water Reservoir

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18062871 ◽

2021 ◽

Vol 18 (6) ◽

pp. 2871

Author(s):

Ji Yoon Kim ◽

Usman Atique ◽

Md Mamun ◽

Kwang-Guk An

Keyword(s):

Water Quality ◽

Drinking Water ◽

Water Chemistry ◽

Strong Influence ◽

Water Reservoir ◽

Phosphorus Limitation ◽

Monsoon Precipitation ◽

Chl A ◽

Drinking Water Reservoir

Long-term variations in reservoir water chemistry could provide essential data in making sustainable water quality management decisions. Here, we analyzed the spatiotemporal variabilities of nutrients, sestonic chlorophyll-a (CHL-a), nutrient enrichment, dominant algal species, and overall chemical water health of the third-largest drinking water reservoir in South Korea during 2000–2020. Our results distinctly explained the strong influence of monsoon rainfall on spatial and annual water chemistry variations. We observed a consistent increase in the chemical oxygen demand alluding to organic matter pollutants, while a steady declining trend in the sestonic CHL-a. The long-term total phosphorus (TP) level showed a steady reduction from the riverine zone to the lacustrine area. However, a higher total coliform bacteria (TCB) was observed at the water intake tower sites. TP displayed a strong link to algal CHL-a and ambient nitrogen phosphorus ratios, suggesting a robust phosphorus-limitation state. The severe phosphorus-limitation was also corroborated by the findings of trophic state index deviation. The high and low flow dynamics exhibited the strong influence of intensive rainfall carrying many nutrients and sediments and flushing out the sestonic CHL-a. Successive eutrophic conditions prevailed along with dominating blue-green algae species (Microcystis and Anabaena). We observed a strong positive correlation (r = 0.62) between water temperature and CHL-a and between total suspended solids and TP (r = 0.65). The multi-metric water pollution index characterized the overall water quality as ‘good’ at all the study sites. In conclusion, the long-term spatiotemporal variabilities of the ecological functions based on the nutrient-CHL-a empirical models are regulated mainly by the intensive monsoon precipitation. The drinking water could become hazardous under the recurrent eutrophication events and chemical degradations due to uncontrolled and untreated inflow of sewage and wastewater treatment plant effluents. Therefore, we strongly advocate stringent criteria to mitigate phosphorus and organic pollutant influx for sustainable management of Daecheong Reservoir.

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