Assessing the water quality status for special use is the main objective of any water quality monitoring studies. The water quality index (WQI) is a mathematical instrument used to transform large quantities of water quality data into a single number which represents the water quality level. In fact, developing WQI in an area is a fundamental process in the planning of land use and water resources management. In this study, a simple methodology based on multivariate analysis is developed to create a groundwater quality index (GWQI), with the aim of identifying places with best quality for drinking within the Qazvin province, west central of Iran. The methodology is based on the definition of GWQI using average value of eight cation and anion parameters for 163 wells during a 3-year period. The proportion of observed concentrations to the maximum allowable concentration is calculated as normalized value of each parameter in observing wells. Final indices for each well are calculated considering weight of each parameter. In order to assess the groundwater quality of study area, the derived indices are compared with those of well-known mineral waters. Using developed indices, groundwater iso-index map for study area and the map of areas of which the indices are near to mineral waters was drawn. In the case study, the GWQI map reveals that groundwater quality in two areas is extremely near to mineral water quality. Created index map provides a comprehensive picture of easily interpretable for regional decision makers for better planning and management.
We propose and apply a Fourier-based symmetry reduction scheme to remove, or
quotient, the streamwise translation symmetry of Laser-Induced-Fluorescence
measurements of turbulent pipe flows that are viewed as dynamical systems in a
high-dimensional state space. We also explain the relation between Taylor's
hypothesis and the comoving frame velocity $U_{d}$ of the turbulent orbit in
state space. In particular, in physical space we observe flow structures that
deform as they advect downstream at a speed that differs significantly from
$U_{d}$. Indeed, the symmetry reduction analysis of planar dye concentration
fields at Reynolds number $\mathfrak{\mathsf{Re}}=3200$ reveals that the speed
$u$ at which high concentration peaks advect is roughly 1.43 times $U_{d}$. In
a physically meaningful symmetry-reduced frame, the excess speed
$u-U_{d}\approx0.43U_{d}$ can be explained in terms of the so-called geometric
phase velocity $U_{g}$ associated with the orbit in state space. The
'self-propulsion velocity' $U_{g}$ is induced by the shape-changing dynamics of
passive scalar structures observed in the symmetry-reduced frame, in analogy
with that of a swimmer at low Reynolds numbers.Comment: arXiv admin note: substantial text overlap with arXiv:1407.748
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