Event Title

Groundwater contamination transport modeling in Andean river aquifer in Peru

Presenter Information

Richard Peralta
Bassel Timani

Location

Eccles Conference Center

Event Website

http://water.usu.edu/

Start Date

3-29-2011 2:20 PM

End Date

3-29-2011 2:40 PM

Description

Note, this revised abstract replaces one entitles Groundwater contamination transport modeling in coastal Peru. Pacific coastal rivers of Peru receive snowmelt runoff from the Andes. These rivers recharge coastal aquifers to which they are hydraulically connected. The quality of the river and ground water differs from basin to basin. Many aquifers demonstrate the general Chebotarev sequence of bicarbonate to sulfate to chloride to sulfate, as one progresses from the Andes to the ocean. North of Lima, Chillon River aquifer groundwater sulfate concentrations exceed health advisory limits, before chloride concentrations begin to dominate. Water managers have been concerned about significant changes in measured concentrations. Being able to predict groundwater sulfate concentrations is important for the increasing population. Developing a pilot groundwater contaminant transport model involved intensive data and simulation model evaluation, and included re-positioning and re-calibrating an existing groundwater flow model for the Chillon River aquifer. Flow model re-calibration significantly improved calibration head-matching statistics. An equilibrium-concentration approach guided sulfate contaminant transport model calibration. Because the flow-related data were known with more certainty than the transport-related data, the newly developed flow model parameters were not varied during transport model calibration. Transport model calibration optimization identified seepage water sulfate concentrations, that would produce a quasi-steady-state concentration distribution, to best match field measurements. Both the flow model and the transport model are as accurate as the data upon which they are based. They can be improved by enhanced positioning of pumping wells within the model grid, and increased horizontal and vertical discretization.

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Mar 29th, 2:20 PM Mar 29th, 2:40 PM

Groundwater contamination transport modeling in Andean river aquifer in Peru

Eccles Conference Center

Note, this revised abstract replaces one entitles Groundwater contamination transport modeling in coastal Peru. Pacific coastal rivers of Peru receive snowmelt runoff from the Andes. These rivers recharge coastal aquifers to which they are hydraulically connected. The quality of the river and ground water differs from basin to basin. Many aquifers demonstrate the general Chebotarev sequence of bicarbonate to sulfate to chloride to sulfate, as one progresses from the Andes to the ocean. North of Lima, Chillon River aquifer groundwater sulfate concentrations exceed health advisory limits, before chloride concentrations begin to dominate. Water managers have been concerned about significant changes in measured concentrations. Being able to predict groundwater sulfate concentrations is important for the increasing population. Developing a pilot groundwater contaminant transport model involved intensive data and simulation model evaluation, and included re-positioning and re-calibrating an existing groundwater flow model for the Chillon River aquifer. Flow model re-calibration significantly improved calibration head-matching statistics. An equilibrium-concentration approach guided sulfate contaminant transport model calibration. Because the flow-related data were known with more certainty than the transport-related data, the newly developed flow model parameters were not varied during transport model calibration. Transport model calibration optimization identified seepage water sulfate concentrations, that would produce a quasi-steady-state concentration distribution, to best match field measurements. Both the flow model and the transport model are as accurate as the data upon which they are based. They can be improved by enhanced positioning of pumping wells within the model grid, and increased horizontal and vertical discretization.

https://digitalcommons.usu.edu/runoff/2011/AllAbstracts/27