TY - JOUR
T1 - Impoundments increase potential for phosphorus retention and remobilization in an urban stream
AU - Vo, Nguyen Xuan Que
AU - Van Doan, Tuan
AU - Kang, Hojeong
PY - 2014/6
Y1 - 2014/6
N2 - Weirs are conventional structures that control water level and velocity in streams to facilitate water resource management. Despite many weirs built in streams, there is little information how weirs change hydrology regime and how that translates to sediment and phosphorus (P) responses. This study evaluated the infuence of weirs on P retention and mobilization in an urban tributary of the Han River in Korea. Total P concentrations in sediments upstream of weirs were higher than the downstream site, mainly due to the increase of potentially available fractions (labile P and aluminum- and iron-bound P) (p < 0.05). Equilibrium phosphorus concentrations (EPCo) were lower than soluble reactive phosphorus (SRP) concentrations of stream waters, but there was an increasing trend of sediment EPCo upstream of weirs compared to the downstream site (p < 0.001) indicating a greater potential for P release upstream of weirs. Sediment core incubation showed that SRP release rates upstream of weirs were higher than the downstream site under anoxic conditions of the water column (p < 0.01), but not under oxic conditions. SRP release rates under anoxic conditions were greater than that measured under oxic conditions. Un-neutral pH and increased temperature could also enhance SRP release rates upstream of weirs. We conclude that weirs can increase P retention within stream sediments and potentially promote signifcant P releases into waters, which in turn cause eutrophication.
AB - Weirs are conventional structures that control water level and velocity in streams to facilitate water resource management. Despite many weirs built in streams, there is little information how weirs change hydrology regime and how that translates to sediment and phosphorus (P) responses. This study evaluated the infuence of weirs on P retention and mobilization in an urban tributary of the Han River in Korea. Total P concentrations in sediments upstream of weirs were higher than the downstream site, mainly due to the increase of potentially available fractions (labile P and aluminum- and iron-bound P) (p < 0.05). Equilibrium phosphorus concentrations (EPCo) were lower than soluble reactive phosphorus (SRP) concentrations of stream waters, but there was an increasing trend of sediment EPCo upstream of weirs compared to the downstream site (p < 0.001) indicating a greater potential for P release upstream of weirs. Sediment core incubation showed that SRP release rates upstream of weirs were higher than the downstream site under anoxic conditions of the water column (p < 0.01), but not under oxic conditions. SRP release rates under anoxic conditions were greater than that measured under oxic conditions. Un-neutral pH and increased temperature could also enhance SRP release rates upstream of weirs. We conclude that weirs can increase P retention within stream sediments and potentially promote signifcant P releases into waters, which in turn cause eutrophication.
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U2 - 10.4491/eer.2014.19.2.175
DO - 10.4491/eer.2014.19.2.175
M3 - Article
AN - SCOPUS:84903398653
VL - 19
SP - 175
EP - 184
JO - Environmental Engineering Research
JF - Environmental Engineering Research
SN - 1226-1025
IS - 2
ER -