Brenda Aguilar Fernandez – Undergraduate – Anthropology & Environmental Science
Tropical Cyclones in the Southwest Pacific: Mitigation of Water Supply Impacts in Fiji and Vanuatu
The Pacific Island region is exceptionally vulnerable to the damage and disaster created by tropical cyclones. They affect the quality of life for many local communities on the Fiji and Vanuatu islands and continue to weaken their already limited water resources, infrastructure, and economic development. In 2012, tropical cyclone Evan swept through Fiji and other surrounding countries costing an estimated 315 million USD in damages, and more recently in 2015, a category 5 cyclone affected more than 70% of the population of Vanuatu, now considered one of the worse natural disasters in the history of the island. With the rise of climate change, these tropical cyclones are becoming more frequent and disastrous, posing a threat to clean, usable water supplies that are a staple for various socio-economic sectors in the Pacific Islands. In response to catastrophic cyclones, several mitigation solutions have arisen from the traditional ecological knowledge of indigenous people across Fiji and Vanuatu. These cost-effective and sustainable solutions can provide valuable insight and guidance for other regions being affected by tropical cyclone events, in addition to helping island communities prepare and respond to them in an effective and timely manner. Here, I’ll address the impacts of tropical cyclones on water supplies in the Pacific Islands of Fiji and Vanuatu while highlighting the mitigation techniques being used to adapt and cope with these extreme weather events.
Evan Hartshorn – Graduate– Hydrology
Hydrologic Controls on Dust Emission at Willcox Playa, Arizona
Willcox Playa is a remnant of pluvial lake Cochise which under specific conditions can be a major dust source in this region. Variable precipitation intensity and extended dry periods heavily influence characteristics of the playa’s surface crusts and act as a mechanism to increase dust emission potential. Dust emission flux measurements were collected at Willcox Playa in both November 2019 and May 2021 using the Portable In-situ Wind Erosion Laboratory (PI-SWERL). Using monthly precipitation data from the Western Regional Climate Center at a nearby weather station in Willcox, AZ, precipitation prior to dust emission measurements was analyzed in relation to the types of playa surface crusts present on Willcox Playa.
Preliminary results suggest that Willcox Playa has a dynamic relationship between precipitation distribution and dust emission. A wide variety of crust types were documented, such as peeling crusts or crusts with sand sized aggregates of silt and clay, that form because of variable quantities of localized precipitation across the playa. The proposed model for dust emission at Willcox Playa suggests smaller precipitation events create thin (<5 mm) peeling mud cracks above the existing playa crusts. After sufficiently drying, peeling curved edges of the thin mud cracks are entrained by wind, and when mobilized act as sand sized particles saltating on the playa deposits as evidenced by small patches of eolian aggregate ripples across the playa. Variable precipitation distribution plays a role in forming different crust types at Willcox Playa, creating a dynamic environment for dust emission to occur.
Michael Sprinkle - Undergraduate- Environmental Science, Ecological Conservation & Restoration
Land Use Impacts on Flooding and Drought during Times of Climate Change: A Case Study from the Mediterranean.
Land and water systems of the Mediterranean are changing, thus impacting the water security of communities. Land management decisions, in the context of climate change impact risk of flood related disasters and the conversely critical shortages during drought periods. There has been a legacy of timber production/plantations and abandonment of land following intensive cultivation, leads to deforestation and loss of ecosystem integrity. These are coupled with changing climate and disturbances, including more severe fires and weather patterns, The combined effect of these decisions and changes are degrading the ecosystem services of flow modulation and storage. In particular, water systems during periods of extremes, flooding, and drought are being impacted. A legacy of timber production, coupled with a more critical fire environment is increasing fire severity. This in turn leads to higher run-off rates during floods and lower storage flows during droughts. While land abandonment without restoration is likewise making the water systems more susceptible to extreme water events. This is due to loss of ecosystem functioning in the storage and runoff modulation. While the previously used infrastructure is no longer being kept-up, creating a feedback system of more severe flooding and drought conditions. These issues can be mitigated with restoration of ecosystem services, along with a more holistic look at the use and management of the land, incorporating land and water. In particular, this means incorporating natural ecosystem composition and structure, restructuring of stream geography, and the development of integrated water systems -using both ecosystem services and built infrastructure.
Claudia Pighetti – Undergraduate- Environmental Science
Drought and its Impact on Agriculture in the Iberian Peninsula
The Iberian Peninsula of southern Europe is an agriculturally-active region in the Mediterranean located within an ecotone between historically humid and arid regions. Within the past century, droughts have become increasingly frequent and intense in this region, with climatic conditions becoming significantly drier from 1970 on than in prior decades. About 43.7% of land in the Iberian Peninsula is used for agriculture, but only about 4.8% is irrigated. And as the Iberian Peninsula’s agricultural system relies heavily on rain, drought events are a huge cause of concern for the future of agriculture in the peninsula. In this study, I examine the ways in which drought has historically changed in this region and how these droughts have impacted agriculture activity.
Chase Vigue- Undergraduate - Environmental Science
Fire's Effect on Water Repellent Soils in Southeastern Australia
How does fire affect soil's ability to absorb water in Australia? Water-repellent soils are well documented in southeastern Australia, specifically in the states of Victoria and New South Wales. as well as the western United States, however, little is known about fire’s effects on the water repellency of the soils. It is often viewed that the enhanced soil water repellency caused by fire is a key factor increasing runoff and erosion following the burn. This paper examines the effects of fire on soil water repellency using studies done in Australia following major bushfires, while acknowledging the soil's naturally high repellency in the area to determine if this is an independent condition or induced by the naturally occurring fires. Data collected from the Water Drop Penetration Time (WDPT) test done on soils that experienced different severity of burns and unburned soil. The WDPT consists of placing a drop of water on the surface soil, and measuring the time until complete penetration. Using this test on previously burnt soils revealed, that fire’s effects on the soil changed based on temperature and would differ between the surface and subsurface layers of the soil.