Predicting the effect of deep-rooted hybrid poplars on the groundwater flow system at a large-scale phytoremediation site.
Estimating the effect of phreatophytes on the groundwater flow field is critical in the design or evaluation of a phytoremediation system. Complex hydrogeological conditions and the transient water use rates of trees require the application of numerical modeling to address such issues as hydraulic containment, seasonality, and system design. In 1999, 809 hybrid poplars and willows were planted to phytoremediate the 317 and 319 Areas of Argonne National Laboratory near Chicago, Illinois. Contaminants of concern are volatile organic compounds and tritium. The site hydrogeology is a complex framework of glacial tills interlaced with sands, gravels, and silts of varying character, thickness, and lateral extent. A total of 420 poplars were installed using a technology to direct the roots through a 25-ft (8-m)-thick till to a contaminated aquifer. Numerical modeling was used to simulate the effect of the deep-rooted poplars on this aquifer of concern. Initially, the best estimates of input parameters and boundary conditions were determined to provide a suitable match to historical transient ground-water flow conditions. The model was applied to calculate the future effect of the developing deep-rooted poplars over a 6 year period. The first 3 years represent the development period of the trees. In the fourth year, canopy closure is expected to occur; modeling continues through the first 3 years of the mature plantation. Monthly estimates of water use by the trees are incorporated. The modeling suggested that the mature trees in the plantation design will provide a large degree of containment of groundwater from the upgradient source areas, despite the seasonal nature of the trees' water consumption. The results indicate the likely areas where seasonal dewatering of the aquifer may limit the availability of water for the trees. The modeling also provided estimates of the residence time of groundwater in the geochemically altered rhizosphere of the plantation.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- EM
- DOE Contract Number:
- DE-AC02-06CH11357
- OSTI ID:
- 942875
- Report Number(s):
- ANL/EA/JA-35494; TRN: US200923%%663
- Journal Information:
- Int. J. Phytoremediat., Vol. 3, Issue 1 ; Mar. 2001; ISSN 1522-6514
- Country of Publication:
- United States
- Language:
- ENGLISH
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Related Subjects
63 RADIATION, THERMAL, AND OTHER ENVIRONMENTAL POLLUTANT EFFECTS ON LIVING ORGANISMS AND BIOLOGICAL MATERIALS
ANL
BIOREMEDIATION
BOUNDARY CONDITIONS
GROUND WATER
NUMERICAL ANALYSIS
ORGANIC COMPOUNDS
POPLARS
SIMULATION
TREES
TRITIUM
VOLATILE MATTER
WATER
WATER REMOVAL
WATER USE