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Effects of reservoir stratification and watershed hydrology on manganese and iron in a dam‐regulated river
Author(s) -
Munger Zackary W.,
Shahady Thomas D.,
Schreiber Madeline E.
Publication year - 2017
Publication title -
hydrological processes
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.222
H-Index - 161
eISSN - 1099-1085
pISSN - 0885-6087
DOI - 10.1002/hyp.11131
Subject(s) - hydrology (agriculture) , environmental science , stratification (seeds) , hydropower , eutrophication , water quality , watershed , discharge , water column , streamflow , sediment , drainage basin , geology , nutrient , oceanography , ecology , geomorphology , seed dormancy , botany , germination , geotechnical engineering , cartography , machine learning , dormancy , computer science , geography , biology
The presence of metals, including manganese (Mn) and iron (Fe), adversely impacts water quality. In seasonally stratified reservoirs, Mn and Fe can accumulate in the water column due to reducing conditions in sediments and be released to downstream rivers through dam discharge. In addition to reservoir stratification influences, the release of metals downstream is influenced by hydrologic conditions in the river. We examined the seasonal and spatial variability of Mn and Fe concentrations in a eutrophic, hydropower reservoir and the downstream river over a two‐year period. Overall, we found that reservoir stratification was a strong predictor of tailrace Mn and Fe concentrations but that tailrace Fe concentrations were also influenced by dam discharge. Downgradient of the tailrace, river discharge and suspended sediment were the dominant predictors of both Mn and Fe concentrations. Using our data, we develop a conceptual model of seasonal and hydrologic drivers of metal concentrations. The model can be modified for other systems aiding drinking water utilities and other water users in forecasting under what seasonal and hydrologic conditions that Mn and Fe concentrations in river systems are likely to be elevated.