Influence of hummocks and emergent vegetation on hydraulic performance in a surface flow wastewater treatment wetland
Article first published online: 11 NOV 2010
Copyright 2010 by the American Geophysical Union.
Water Resources Research
Volume 46, Issue 11, November 2010
How to Cite
2010), Influence of hummocks and emergent vegetation on hydraulic performance in a surface flow wastewater treatment wetland, Water Resour. Res., 46, W11518, doi:10.1029/2010WR009512., , , , , and (
- Issue published online: 11 NOV 2010
- Article first published online: 11 NOV 2010
- Manuscript Accepted: 27 JUL 2010
- Manuscript Received: 5 MAY 2010
- constructed wetlands;
- solute transport;
- numerical modeling
 A series of tracer experiments were conducted biannually at the start and end of the vegetation growing season in a surface flow wastewater treatment wetland located near Phoenix, AZ. Tracer experiments were conducted prior to and following reconfiguration and replanting of a 1.2 ha treatment wetland from its original design of alternating shallow and deep zones to incorporate hummocks (shallow planting beds situated perpendicular to flow). Tracer test data were analyzed using analysis of moments and the one-dimensional transport with inflow and storage numerical model to evaluate the effects of the seasonal vegetation growth cycle and hummocks on solute transport. Following reconfiguration, vegetation coverage was relatively small, and minor changes in spatial distribution influenced wetland hydraulics. During start-up conditions, the wetland underwent an acclimation period characterized by small vegetation coverage and large transport cross-sectional areas. At the start of the growing season, new growth of emergent vegetation enhanced hydraulic performance. At the end of the growing season, senescing vegetation created short-circuiting. Wetland hydrodynamics were associated with high volumetric efficiencies and velocity heterogeneities. The hummock design resulted in breakthrough curves characterized by multiple secondary tracer peaks indicative of varied flow paths created by bottom topography.