Analysis of water source contribution and its impact on hydrological
structural connectivity in urban plain river network area based on
stable isotopes
Abstract
Water sources carry chemicals that can have a significant impact on the
water environment of a river network, and understanding the contribution
of different water sources to the river network can help to manage the
pollution of the river network at its source. Hydrological connectivity
of a river network affects the self-purification capacity and flood
prevention capacity of the river. Thus an isotope tracer approach was
applied to figure out the contribution rate of different water bodies to
a river network and hydrological connectivity was quantified by
introducing retention rate. Changzhou city was selected as the study
area because it is an urbanized city with the characteristics of plain
river network and it is faced with poor hydrological connectivity due to
artificial constructions (dams and pumps) and human activity
(urbanization). River water, well water (shallow groundwater), lake
water and rainfall were collected during the flood season and nonflood
season, and hydrogen and oxygen isotopes were determined. The temporal
and spatial variations in hydrogen and oxygen isotopes in different
water bodies and the state of the water cycle in different water bodies
were analyzed. IsoSource and MixSIAR models were established to analyze
the contribution rate of river network water sources in the study area,
and their effectiveness was compared. Results of MixSIAR model were
selected to evaluate the hydrological connectivity of the river network
in the study area, providing a method to quantify the hydrological
connectivity of specific river of the river network in Changzhou. This
method could also be applied to other urban plain river network area to
study its river connectivity.