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Seasonal-Spatial Distribution and Long-Term Variation of Transparency in Xin'anjiang Reservoir: Implications for Reservoir Management.

Wu Z, Zhang Y, Zhou Y, Liu M, Shi K, Yu Z - Int J Environ Res Public Health (2015)

Bottom Line: The seasonal effects were distinct, with lower values in the summer than in the winter, most likely due to river runoff and phytoplankton biomass increases.The transparency decreased significantly with a linear slope of 0.079 m/year, indicating a 2.05 m decrease and a marked decrease in water quality.A marked increase occurred in chlorophyll a (Chla) concentration, and a significant correlation was found between the transparency and Chla concentration, indicating that phytoplankton biomass can partially explain the long-term trend of transparency in Xin'anjiang Reservoir.

View Article: PubMed Central - PubMed

Affiliation: Chun'an Environmental Monitoring Station, Hangzhou 311700, China. caepb@126.com.

ABSTRACT
Water transparency is a useful indicator of water quality or productivity and is widely used to detect long-term changes in the water quality and eutrophication of lake ecosystems. Based on short-term spatial observations in the spring, summer, and winter and on long-term site-specific observation from 1988 to 2013, the spatial, seasonal, long-term variations, and the factors affecting transparency are presented for Xin'anjiang Reservoir (China). Spatially, transparency was high in the open water but low in the bays and the inflowing river mouths, reflecting the effect of river runoff. The seasonal effects were distinct, with lower values in the summer than in the winter, most likely due to river runoff and phytoplankton biomass increases. The transparency decreased significantly with a linear slope of 0.079 m/year, indicating a 2.05 m decrease and a marked decrease in water quality. A marked increase occurred in chlorophyll a (Chla) concentration, and a significant correlation was found between the transparency and Chla concentration, indicating that phytoplankton biomass can partially explain the long-term trend of transparency in Xin'anjiang Reservoir. The river input and phytoplankton biomass increase were associated with soil erosion and nutrient loss in the catchment. Our study will support future management of water quality in Xin'anjiang Reservoir.

No MeSH data available.


Related in: MedlinePlus

Linear relationships between the mean transparency of three seasons from 2013 to 2014 and the distance to site 19 for the Xin’anjiang River (sites 9–19) (a), to site 8 for the Fuqiangxi River (sites 1–8) (b), and to site 34 for the Wuqiangxi River (sites 28–34) (c).
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ijerph-12-09492-f003: Linear relationships between the mean transparency of three seasons from 2013 to 2014 and the distance to site 19 for the Xin’anjiang River (sites 9–19) (a), to site 8 for the Fuqiangxi River (sites 1–8) (b), and to site 34 for the Wuqiangxi River (sites 28–34) (c).

Mentions: Figure 2a–c shows the substantial spatial differences among transparency distributions in the spring, summer, and winter with two different types are considered. The first type (I) of low transparency is characteristic of river mouths, including Xin’anjiang River, Wuqiangxi River and Fuqiangxi River, which represent 60%, 20% and 10%, respectively, of the annual mean incoming runoff of Xin’anjiang Reservoir (Figure 1 and Figure 2a–c). The river mouths are distinguished by low values of transparency for most of the year, less than 3 m in most cases. The average transparency of the first type was 2.30 ± 1.21 m. From the upstream reaches of the three incoming rivers to the open water around the reservoir, transparency gradually increases. For example, the water transparency is greatly affected by the Xin’anjiang River and maintains a very low value from the upstream site 10 at Jiekou (1.28 ± 0.10 m) to a high value in the open site 19 at Xiaojinshan (2.90 ± 2.27 m) along more than 30 km for all three seasons. To qualitatively assess the effect of the inflowing river on the distribution of transparency, we performed a linear regression between transparency and the distance to the open water. In detail, the distances to site 19 for the Xin’anjiang River, to site 8 for the Fuqiangxi River, and to site 34 for the Wuqiangxi River were calculated. A significant linear relationship was found between the transparency and the distance to the open water for the Xin’anjiang River for sites 9–19 (r2 = 0.97, p < 0.001), the Fuqiangxi River for sites 1–8 (r2 = 0.65, p < 0.05), and the Wuqiangxi River for sites 28-34 (r2 = 0.88, p < 0.005) (Figure 3), indicating the significant effect of the incoming river on the transparency in Xin’anjiang Reservoir.


Seasonal-Spatial Distribution and Long-Term Variation of Transparency in Xin'anjiang Reservoir: Implications for Reservoir Management.

Wu Z, Zhang Y, Zhou Y, Liu M, Shi K, Yu Z - Int J Environ Res Public Health (2015)

Linear relationships between the mean transparency of three seasons from 2013 to 2014 and the distance to site 19 for the Xin’anjiang River (sites 9–19) (a), to site 8 for the Fuqiangxi River (sites 1–8) (b), and to site 34 for the Wuqiangxi River (sites 28–34) (c).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4555293&req=5

ijerph-12-09492-f003: Linear relationships between the mean transparency of three seasons from 2013 to 2014 and the distance to site 19 for the Xin’anjiang River (sites 9–19) (a), to site 8 for the Fuqiangxi River (sites 1–8) (b), and to site 34 for the Wuqiangxi River (sites 28–34) (c).
Mentions: Figure 2a–c shows the substantial spatial differences among transparency distributions in the spring, summer, and winter with two different types are considered. The first type (I) of low transparency is characteristic of river mouths, including Xin’anjiang River, Wuqiangxi River and Fuqiangxi River, which represent 60%, 20% and 10%, respectively, of the annual mean incoming runoff of Xin’anjiang Reservoir (Figure 1 and Figure 2a–c). The river mouths are distinguished by low values of transparency for most of the year, less than 3 m in most cases. The average transparency of the first type was 2.30 ± 1.21 m. From the upstream reaches of the three incoming rivers to the open water around the reservoir, transparency gradually increases. For example, the water transparency is greatly affected by the Xin’anjiang River and maintains a very low value from the upstream site 10 at Jiekou (1.28 ± 0.10 m) to a high value in the open site 19 at Xiaojinshan (2.90 ± 2.27 m) along more than 30 km for all three seasons. To qualitatively assess the effect of the inflowing river on the distribution of transparency, we performed a linear regression between transparency and the distance to the open water. In detail, the distances to site 19 for the Xin’anjiang River, to site 8 for the Fuqiangxi River, and to site 34 for the Wuqiangxi River were calculated. A significant linear relationship was found between the transparency and the distance to the open water for the Xin’anjiang River for sites 9–19 (r2 = 0.97, p < 0.001), the Fuqiangxi River for sites 1–8 (r2 = 0.65, p < 0.05), and the Wuqiangxi River for sites 28-34 (r2 = 0.88, p < 0.005) (Figure 3), indicating the significant effect of the incoming river on the transparency in Xin’anjiang Reservoir.

Bottom Line: The seasonal effects were distinct, with lower values in the summer than in the winter, most likely due to river runoff and phytoplankton biomass increases.The transparency decreased significantly with a linear slope of 0.079 m/year, indicating a 2.05 m decrease and a marked decrease in water quality.A marked increase occurred in chlorophyll a (Chla) concentration, and a significant correlation was found between the transparency and Chla concentration, indicating that phytoplankton biomass can partially explain the long-term trend of transparency in Xin'anjiang Reservoir.

View Article: PubMed Central - PubMed

Affiliation: Chun'an Environmental Monitoring Station, Hangzhou 311700, China. caepb@126.com.

ABSTRACT
Water transparency is a useful indicator of water quality or productivity and is widely used to detect long-term changes in the water quality and eutrophication of lake ecosystems. Based on short-term spatial observations in the spring, summer, and winter and on long-term site-specific observation from 1988 to 2013, the spatial, seasonal, long-term variations, and the factors affecting transparency are presented for Xin'anjiang Reservoir (China). Spatially, transparency was high in the open water but low in the bays and the inflowing river mouths, reflecting the effect of river runoff. The seasonal effects were distinct, with lower values in the summer than in the winter, most likely due to river runoff and phytoplankton biomass increases. The transparency decreased significantly with a linear slope of 0.079 m/year, indicating a 2.05 m decrease and a marked decrease in water quality. A marked increase occurred in chlorophyll a (Chla) concentration, and a significant correlation was found between the transparency and Chla concentration, indicating that phytoplankton biomass can partially explain the long-term trend of transparency in Xin'anjiang Reservoir. The river input and phytoplankton biomass increase were associated with soil erosion and nutrient loss in the catchment. Our study will support future management of water quality in Xin'anjiang Reservoir.

No MeSH data available.


Related in: MedlinePlus