Phreatophyte Water Usage

• Independent Peer Review of Tamarisk & Russian Olive Evapotranspiration Colorado River Basin

  This report focuses on ten specific questions on the current knowledge about tamarisk and Russian olive (TRO) effects on water availability. The Panel assembled to complete the report was asked to address whether TRO water use, or evapotranspiration (ET), is sufficiently understood to reasonably predict the water savings associated with TRO removal and native species restoration. The panel was also asked to detail where and how future research and demonstration projects could best contribute to tamarisk and Russian olive management and its role in the stewardship of Western rivers.
• Why Do We Care About ET?
• Quantifying Riparian Evapotranspiration
• Approaches to ET Measurement
  As described in this short paper, methods for measuring ET range from relatively direct but resource-intensive methods, to more easily obtained empirical estimates.
• Evapotranspiration Measurement Methods

  This short paper describes different ET measurement techniques and the assumptions that are made for each technique. 
• ET–The Key to Balancing the Water Budget in the Southwest
• Colorado River Basin Water Supply and Demand Study Executive Summary

  The purpose of the Study, funded by the Bureau of Reclamation, was to define current and future imbalances in water supply and demand in the Basin and the adjacent areas of the Basin States that receive Colorado River water over the next 50 years (through 2060), and to develop and analyze adaptation and mitigation strategies to resolve those imbalances.
• Tamarisk Control, Water Salvage, and Wildlife Habitat Restoration Along Rivers in the Western United States
• Native Versus Invasive: Plant Water Use in the Middle Rio Grande Basin
• Assessing the Potential Impact of Invasive Species Water Use on the Lower Colorado River

  Using three different methods to examine evapotranspiration, this poster presents the findings from a study that examined groundwater levels pre- and post-fire in a tamarisk dominated area at Cibola National Wildlife Refuge.  
• Colorado River Basin Water Supply and Demand Study: Study Report
  The Colorado River Basin Water Supply and Demand Study (Study), initiated in January

  2010, was conducted by the Bureau of Reclamation’s (Reclamation) Upper Colorado and

  Lower Colorado regions, and agencies representing the seven Colorado River Basin States.

  As defined in the Plan of Study, the purpose of the Study is to define current and

  future imbalances in water supply and demand in the Basin and the adjacent areas of the

  Basin States that receive Colorado River water over the next 50 years (through 2060), and to

  develop and analyze adaptation and mitigation strategies to resolve those imbalances. The

  Study does not result in a decision as to how future imbalances will or should be addressed.

  Rather, the Study provides a common technical foundation that frames the range of potential

  imbalances that may be faced in the future and the range of solutions that may be considered

  to resolve those imbalances.
• Tamarix Transpiration Along a Semiarid River Has Negligible Impacts on Water Resources; Alyson McDonald
• A prescription for drug-free rivers: uptake of pharmaceuticals by a widespread streamside willow; Carmen Franks, David Pearce, Stewart Rood

   

  A prescription for drug-free rivers: uptake of pharmaceuticals by a widespread streamside willow

  Carmen Franks, David Pearce, Stewart Rood

   

  Abstract:

  Following human excretion and limited removal with wastewater treatment, pharmaceuticals are accumulating in rivers worldwide. These chemicals can challenge the health of fish and aquatic organisms and since rivers provide drinking water sources, there is concern for cumulative exposure to humans. In this study, we discovered that sandbar willow (Salix exigua), a predominant riparian shrub along streams throughout North America, has the capacity to quickly remove pharmaceuticals from aqueous solutions. Our study tracked [3 H]- or [14C]-labeled substances including 17α-ethynylestradiol (EE2), a synthetic estrogen in oral contraceptives; the antihypertensive, diltiazem (DTZ); and the anti-anxiety drug, diazepam (DZP); and for comparison, atrazine (ATZ), a root-absorbed herbicide. In growth chambers, willow saplings removed 40–80% of the substances from solutions in 24 h. Following uptake, the EE2 and DTZ were retained within the roots, while DZP and ATZ were partly passed on to the shoots. The absorbed EE2 was unextractable and apparently bound to the root tissue, while DTZ, DZP, and ATZ remained largely soluble (extractable). The uptake and translocation of the pharmaceuticals, reflected in the transpiration stream and root concentration factors, were reasonably predicted from their physicochemical properties, including octanol-water partitioning coefficients. These findings suggest the removal of pharmaceuticals as an unrecognized ecosystem service provided by riparian vegetation and especially the inundation tolerant sandbar willow. This encourages the conservation of riparian willows that line riverbanks, to remove pharmaceuticals and other contaminants. This phytoremediation also encourages the preservation of complex, braided channels and islands, which increase the extent of stream shorelines and riparian willows.