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Role of interaction zones between surface and ground waters in DOC transport and processing: considerations for river restoration
Author(s) -
VERVIER PHILIPPE,
DOBSON MIKE,
PINAY GILLES
Publication year - 1993
Publication title -
freshwater biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.297
H-Index - 156
eISSN - 1365-2427
pISSN - 0046-5070
DOI - 10.1111/j.1365-2427.1993.tb00763.x
Subject(s) - dissolved organic carbon , environmental science , hydrology (agriculture) , phosphorus , subsurface flow , surface water , bar (unit) , streams , geology , groundwater , environmental engineering , chemistry , oceanography , geotechnical engineering , organic chemistry , computer network , computer science
SUMMARY1 A study of dissolved organic carbon (DOC), nitrates and total dissolved phosphorus (TDP) concentrations, conductivity and bacterial numbers was undertaken in subsurface water of the Garonne River (France) under low‐flow conditions. The velocity of subsurface flow through a 300‐m gravel bar, during this study, was less than 43 m day −1 . DOC, nitrates and TDP concentrations, conductivity and bacterial numbers fluctuated within the gravel bar with no discernible spatial pattern. Bacterial abundance was correlated with DOC concentration. Results were compared to a previous study of the Stillaguamish River (U.S.A.) (Vervier & Naiman, 1992). 2 These studies provide evidence that gravel bars are important in the processing of DOC by bacteria in the subsurface water. Bacterial activity is, in turn, determined by sources of DOC from upstream at high discharge, and by patchy local microhabitats at low discharge. 3 Restoration of rivers should incorporate, wherever possible, meanders with associated gravel bars and riffles. These will improve DOC‐processing capacity, in addition to other benefits predicted by the Building Block Model (Petersen, Petersen & Lacoursière, 1992).