Hydrologic evaluation of a poplar phytoextraction system

Area of Science:

• Environmental Science
• Hydrology
• Forestry

Background:

• Phytoremediation systems using hybrid poplars are explored for groundwater remediation.
• Contaminated groundwater migration towards surface water bodies poses environmental risks.
• Hydraulic containment of groundwater is crucial for preventing contaminant spread.

Purpose of the Study:

• To evaluate the effectiveness of a hybrid poplar phytoremediation system over seven years.
• To assess the hydraulic capture of impacted groundwater by hybrid poplars.
• To analyze factors challenging the phytoremediation system's performance.

Main Methods:

• A seven-year study involving 349 hybrid poplars (Populous deltoids x Populus nigra 'DN-21').
• Monitoring of diurnal water table fluctuations to assess groundwater extraction.
• Measurement of poplar sap flow during two growing seasons.
• Analysis of topographic constraints, groundwater depth, and surface runoff.

Main Results:

• Substantial and increasing groundwater extraction by hybrid poplars was indicated by water table fluctuations.
• Poplar sap flow measurements corroborated the significant water uptake.
• Despite challenges, the system demonstrated effective hydraulic containment of groundwater.

Conclusions:

• Hybrid poplar phytoremediation is a viable strategy for reducing contaminated groundwater migration.
• Water table fluctuation analysis is an effective, under-utilized tool for evaluating hydraulic capture.
• The study provides a large dataset on poplar sap flow, offering insights into variability.