31 Jul 2024

Reservoir Sediment Deltas of the Southwestern United States: Challenges and Opportunities for Riparian Vegetation Management

Purpose: This technical note summarizes methods used to identify 58 reservoir sediment deltas in the Southwestern United States and California, behind 47 different dams, with potential regional importance as breeding or migratory stopover habitat for three species of riparian vegetation–dependent birds listed under the Endangered Species Act[1]: least Bell’s vireo (LBVI) (Vireo bellii pusillus), southwest willow flycatcher (SWFL) (Empidonax traillii extimus), and yellow-billed cuckoo (YBCU) (Coccyzus americanus). Information on inflow streams, drainage area, and management authority are provided for each delta. This technical note recommends follow-up research on the temporal dynamics of vegetation colonization, growth, and mortality on these deltas to explore the potential value of these geographically widespread hydrogeomorphic features on arid-land rivers for the conservation of riparian vegetation–dependent birds.

2 Aug 2023

Sustainable bank and channel stabilization techniques in arid southwest streams

Abstract: Channel stabilization and enhancement approaches take many different forms and are implemented using varying construction methods, materials, and techniques. The purpose of this study is to provide a comprehensive evaluation of sustainable streambank stabilization measures that are typically applied in arid southwest (SW) streams. This study was conducted at the request of the US Army Corps of Engineers (USACE), Albuquerque District (SPA), and USACE Headquarters. The document also provides rationale for evaluating bank and bed stabilization measures.

5 Aug 2022

Simulating Environmental Conditions for Southwest United States Convective Dust Storms Using the Weather Research and Forecasting Model v4.1

Abstract: Dust aerosols can pose a significant detriment to public health, transportation, and tactical operations through reductions in air quality and visibility. Thus, accurate model forecasts of dust emission and transport are essential to decision makers. While a large number of studies have advanced the understanding and predictability of dust storms, the majority of existing literature considers dust production and forcing conditions of the underlying meteorology independently of each other. Our study works towards filling this research gap by inventorying dust-event case studies forced by convective activity in the Desert Southwest United States, simulating select representative case studies using several configurations of the Weather Research and Forecasting (WRF) model, testing the sensitivity of forecasts to essential model parameters, and assessing overall forecast skill using variables essential to dust production and transport. We found our control configuration captured the initiation, evolution, and storm structure of a variety of convective features admirably well. Peak wind speeds were well represented, but we found that simulated events arrived up to 2 hours earlier or later than observed. Our results show that convective storms are highly sensitive to initialization time and initial conditions that can preemptively dry the atmosphere and suppress the growth of convective storms.