When performing hydrograph separation (EMMA method) with isotope tracers in river confluences (natural large basin), we found that the contribution of each end member sometimes exceeds the theoretical extent of (0,1). For those within this extent, seldom cases can be observed to match the result based on discharge data.
We have considered the disturbance introduced by groundwater recharge along the bank, but the sampling sites is not too far from each other for which we think the contribution can be neglected.
What are the possible controls accounting for this observation? We are waiting for the answer, thank you.
Article Hydrograph separation and precipitation source identificatio...
i dont know much about this cases, but better to check that
Perhaps a few ideas to consider. Mixing of waters at confluences is complex, possibly sampling difficulties. I would suggest, especially for broad rivers as compared to confined channels. I have seen sediment and fecal coliform concentrations as indicators hug the bank for a substantial distance downstream of confluences. Poor mixing or unequal mixing in itself could make sampling difficult as well varying with the discharge of each location across the cross section as it depends on its individual depth and velocity. And there can be primary and secondary velocity vectors. Unless and until the waters are well mixed, then trying to sample the complexity I think would be difficult. If only the eddy margin were sampled, it might become apparent that bank groundwater contributes more than expected. And don’t forget hyphoreic flow, at times the elevation of the river (head) may be higher than hyphoreic or groundwater head moving water or at least preventing groundwater inflow, while at the hydrograph moves toward baseflow, more of the stored groundwater might have the greater head and movement to the stream.
I see a milkshake of contaminates being overlooked as well as the biodiversity impacts forthcoming. However, India has a pollution problem like everyone else in the world and everyone in the world is plagued with ideas that end up in bad ways causing more damage to the environment. The answer to your question, in my opinion would require more in-depth research on why rivers are being
connected in the first place?
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