Date of Award

5-2017

Document Type

Thesis

Department

Environmental Resources Engineering

Thesis Advisor

Theodore Endreny

Abstract

Reestablishing native vegetation in riparian areas of southwestern United States is difficult because of the reduction of natural floods by channelization practices, timing of rainfall, and competition against saltcedar. A previous study demonstrated that clinoptilolite zeolite (CZ) could be used as a wicking material to raise sufficient moisture from shallow groundwater ( < 3 m deep) to sustain plant establishment and growth. However, no studies have explored the effects that CZ has on water stress in established vegetation. This study evaluated the stem water potential (\Jfstem), which increases when plant water stress increases, of desert willow ( Chilopsis linearis) grown in CZ cores or in-situ riparian soil (RS) as part of a riparian zone restoration study in Sunland Park, New Mexico. Root zone volumetric moisture content (0v), plant \j/stem, and leaf chlorophyll content (LCC) for three to four randomly selected specimens in each substrate treatment within different depth to groundwater (DGW) zones were undertaken from June 7 to July 7, 2016. Results from the study showed that in a DGW zone of2 m, plants grown in CZ had significantly lower \j/stem (less water stress) than plants in RS, but in the 1.4 m DGW zone, the RS treatment had significantly higher soil moisture and less water stress. This demonstrated that the effectiveness of CZ in reducing water stress is a function ofDGW. Root zone 0v was negatively correlated with \j/stem, but this relationship was weaker for CZ treatments. Most treatment 8v and LCC averages decreased while \Jfstem increased over the course of the study. This was related to low precipitation and the consistent increase in mean temperatures, with daily maxima reaching as high as 41 °C and during the study period. These results can be used to determine the appropriate groundwater conditions where CZ could be used in future urban riparian restoration projects.

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