Wildland Fire Impacts on Water Yield Across the Contiguous United States

Wildland Fire Impacts on Water Yield Across the Contiguous United States PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 109

Get Book Here

Book Description
Wildland fires in the contiguous United States (CONUS) have increased in size and severity, but much remains unclear about the impact of fire size and burn severity on water supplies used for drinking, irrigation, industry, and hydropower. While some have investigated large-scale fire patterns, long-term effects on runoff, and the simultaneous effect of fire and climate trends on surface water yield, no studies account for all these factors and their interactions at the same time. In this report, we present critical new information for the National Cohesive Wildland Fire Management Strategy—a first-time CONUS-wide assessment of observed and potential wildland fire impacts on surface water yield. First, we analyzed data from 168 fire-affected locations, collected between 1984 and 2013, with machine learning and used climate elasticity models to correct for the local climate baseline impact. Stream gage data show that annual river flow increased most in the Lower Mississippi and Lower and Upper Colorado water resource regions, however they do not show which portion of this increase is caused by fire and which portion results from local climate trends. Our machine learning model identified local climate trends as the main driver of water yield change and determined wildland fires must affect at least 19 percent of a watershed >10 km2 to change its annual water yield. A closer look at 32 locations with fires covering at least 19 percent of a watershed >10 km2 revealed that wildfire generally enhanced annual river flow. Fires increased river flow relatively the most in the Lower Colorado, Pacific Northwest, and California regions. In the Lower Colorado and Pacific Northwest regions, flow increased despite post-fire drought conditions. In southern California, post-fire drought effects masked the flow enhancement attributed to wildfire, meaning that annual water yield declined but not as much as expected based on the decline in precipitation. Prescribed burns in the Southeastern United States did not produce a widespread effect on river flow, because the area affected was typically too small and characterized by only low burn severity. In the second stage of the assessment, we performed full-coverage simulations of the CONUS with the Water Supply Stress Index (WaSSI) hydrologic model (88,000 HUC-12-level watersheds) for the period between 2001 and 2010. This enables us to fill in the gaps of areas with scarce data and to identify regions with large potential increases in post-fire annual water yield (+10 to +50 percent): mid- to high-elevation forests in northeastern Washington, northwestern Montana, central Minnesota, southern Utah, Colorado, and South Dakota, and coastal forests in Georgia and northern Florida. A hypothetical 20-percent forest burn impact scenario for the CONUS suggests that surface yield can increase up to +10 percent in most watersheds, and even more in some watersheds depending on climate, soils, and vegetation. The insights gained from this quantitative analysis have major implications for flood mitigation and watershed restoration, and are vital to forest management policies aimed at reducing fire impact risk and improving water supply under a changing climate.

Wildland Fire Impacts on Water Yield Across the Contiguous United States

Wildland Fire Impacts on Water Yield Across the Contiguous United States PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 109

Get Book Here

Book Description
Wildland fires in the contiguous United States (CONUS) have increased in size and severity, but much remains unclear about the impact of fire size and burn severity on water supplies used for drinking, irrigation, industry, and hydropower. While some have investigated large-scale fire patterns, long-term effects on runoff, and the simultaneous effect of fire and climate trends on surface water yield, no studies account for all these factors and their interactions at the same time. In this report, we present critical new information for the National Cohesive Wildland Fire Management Strategy—a first-time CONUS-wide assessment of observed and potential wildland fire impacts on surface water yield. First, we analyzed data from 168 fire-affected locations, collected between 1984 and 2013, with machine learning and used climate elasticity models to correct for the local climate baseline impact. Stream gage data show that annual river flow increased most in the Lower Mississippi and Lower and Upper Colorado water resource regions, however they do not show which portion of this increase is caused by fire and which portion results from local climate trends. Our machine learning model identified local climate trends as the main driver of water yield change and determined wildland fires must affect at least 19 percent of a watershed >10 km2 to change its annual water yield. A closer look at 32 locations with fires covering at least 19 percent of a watershed >10 km2 revealed that wildfire generally enhanced annual river flow. Fires increased river flow relatively the most in the Lower Colorado, Pacific Northwest, and California regions. In the Lower Colorado and Pacific Northwest regions, flow increased despite post-fire drought conditions. In southern California, post-fire drought effects masked the flow enhancement attributed to wildfire, meaning that annual water yield declined but not as much as expected based on the decline in precipitation. Prescribed burns in the Southeastern United States did not produce a widespread effect on river flow, because the area affected was typically too small and characterized by only low burn severity. In the second stage of the assessment, we performed full-coverage simulations of the CONUS with the Water Supply Stress Index (WaSSI) hydrologic model (88,000 HUC-12-level watersheds) for the period between 2001 and 2010. This enables us to fill in the gaps of areas with scarce data and to identify regions with large potential increases in post-fire annual water yield (+10 to +50 percent): mid- to high-elevation forests in northeastern Washington, northwestern Montana, central Minnesota, southern Utah, Colorado, and South Dakota, and coastal forests in Georgia and northern Florida. A hypothetical 20-percent forest burn impact scenario for the CONUS suggests that surface yield can increase up to +10 percent in most watersheds, and even more in some watersheds depending on climate, soils, and vegetation. The insights gained from this quantitative analysis have major implications for flood mitigation and watershed restoration, and are vital to forest management policies aimed at reducing fire impact risk and improving water supply under a changing climate.

Impact of Wildfire on Annual Water Yield in Large Watersheds

Impact of Wildfire on Annual Water Yield in Large Watersheds PDF Author: Sangki Lee
Publisher:
ISBN:
Category : Water-supply
Languages : en
Pages : 232

Get Book Here

Book Description
Available studies on the effects of wildfire on water yield were conducted in small size watersheds (10km2) and little is known on the scalability of those findings to large watersheds. However, the frequency and occurrence of wildfires that burn large watersheds (100km2) have been increasing in the last decades, resulting on the need to predict their impacts on watershed hydrology. The impact of wildfire on watershed annual water yield is constrained by a complex interaction among several processes, which include hydrologic, geologic, ecologic, climatic alterations. This study investigates short- and long-term responses of annual water yield changes due to wildfire in large watersheds within a paired watershed framework. We, also, propose a new theoretical approach based on the Budyko framework to predict the change in annual water yield due to wildfires, which was originally proposed to explore alterations of water and energy balance within burned watersheds. Long-term responses of annual water yield were predicted by analyzing residuals between annual water yields measured in the field and estimated with paired watershed regression models. Paired watershed analyses were applied to 34 pairs between 11 burned watersheds and 8 unburned watersheds in the Salmon River and Payette River basin (Central Idaho USA), Yellowstone National Park (Wyoming, USA), and Klamath River basin (California, USA). The Budyko framework was conducted in 8 burned watersheds for 10 wildfires, were statistically significant from paired watershed analyses. The Budyko framework was applied both at the yearly time scale (one point for each year) and as originally developed as time averaged (one point for pre and one for post-fire period). This study employed (1) a simple linear model with evaporative index (AET/P) and (2) Fu [1981]'s equation with relative evaporative index (1-Q/P). Results show that annual water yield generally increases after wildfires that burned more than 10% of drainage area with negligible and undetectable changes for smaller burned areas. Exceptions to this trend are for watersheds whose hydrological system is dominated by baseflows (with large ground water storage) and those whose wildfire mainly burned short vegetation. Annual water yield tends to return toward pre-fire condition following the Kuczera's curve, which is related with changes in water demand following regrowth or resuccession of burned trees/vegetation. Post-fire annual water yield increased with burned area, and this correlation was more evident in Mediterranean than in arid climate regions. Post-fire change in annual water yield increases proportionally with drainage area in small watersheds, but this relationship is limited in large watersheds. Results of the Budyko framework show decrease in evapotranspiration rate in most burned watersheds. Reduction in evapotranspiration results in an increase of annual water yield. On the other hand, increase in evaporative index was detected in burned watershed where trees grew quickly during the post-fire period. Climatic conditions can affect the hydrological response during post-fire. Weather condition is an important factor for estimating the annual water yield responses against wildfire. Budyko framework shows that wildfire impact is mitigated under wet weather condition or enhanced under dry weather condition. Results of paired watershed analysis and Budyko framework show a good agreement that post-fire annual water yield responses are strongly correlated with changes in evapotranspiration rate associated with tree mortality or regrowth rate.

Unasylva 251

Unasylva 251 PDF Author: Food and Agriculture Organization of the United Nations
Publisher: Food & Agriculture Org.
ISBN: 9251319103
Category : Technology & Engineering
Languages : en
Pages : 88

Get Book Here

Book Description
Water – drinkable, usable water – is likely to be one of the most limiting resources in the future, given the growing global population, the high water demand of most agricultural production systems, and the confounding effects of climate change. We need to manage water wisely – efficiently, cost-effectively and equitably – if we are to avoid the calamity of a lack of usable water supply. Forested watersheds provide an estimated 75 percent of the world’s accessible freshwater resources, on which more than half the Earth’s people depend for domestic, agricultural, industrial and environmental purposes. Forests therefore, are vital natural infrastructure, and their management can provide “nature-based solutions” for a range of water-related societal challenges. This edition of Unasylva explores that potential.

Hydrologic Effects of a Changing Forest Landscape

Hydrologic Effects of a Changing Forest Landscape PDF Author: National Research Council
Publisher: National Academies Press
ISBN: 0309121086
Category : Science
Languages : en
Pages : 181

Get Book Here

Book Description
Of all the outputs of forests, water may be the most important. Streamflow from forests provides two-thirds of the nation's clean water supply. Removing forest cover accelerates the rate that precipitation becomes streamflow; therefore, in some areas, cutting trees causes a temporary increase in the volume of water flowing downstream. This effect has spurred political pressure to cut trees to increase water supply, especially in western states where population is rising. However, cutting trees for water gains is not sustainable: increases in flow rate and volume are typically short-lived, and the practice can ultimately degrade water quality and increase vulnerability to flooding. Forest hydrology, the study of how water flows through forests, can help illuminate the connections between forests and water, but it must advance if it is to deal with today's complexities, including climate change, wildfires, and changing patterns of development and ownership. This book identifies actions that scientists, forest and water managers, and citizens can take to help sustain water resources from forests.

Wildland Fire in Ecosystems

Wildland Fire in Ecosystems PDF Author:
Publisher:
ISBN:
Category : Fire ecology
Languages : en
Pages : 262

Get Book Here

Book Description


Wildland Fire in Ecosystems

Wildland Fire in Ecosystems PDF Author: U. S. Department Of Agriculture
Publisher: CreateSpace
ISBN: 9781480199118
Category :
Languages : en
Pages : 260

Get Book Here

Book Description
Fire is a natural disturbance that occurs in most terrestrial ecosystems. It is also a tool that has been used by humans to manage a wide range of natural ecosystems worldwide. As such, it can produce a spectrum of effects on soils, water, riparian biota, and wetland components of ecosystems. Fire scientists, land managers, and fire suppression personnel need to evaluate fire effects on these components, and balance the overall benefits and costs associated with the use of fire in ecosystem management. This publication has been written to provide up-to- date information on fire effects on ecosystem resources that can be used as a basis for planning and implementing fire management activities. It is a companion publication to the recently published book, Fire's Effects on Ecosystems by DeBano and others (1998). In the late 1970s, the USDA Forest Service published a series of state-of-knowledge papers about fire effects on vegetation, soils, water, wildlife, and other ecosystem resources. These papers, collectively called "The Rainbow Series" because of their covers, were widely used by forest fire personnel. This publication updates both the Tiedemann and others (1979) paper on fire's effects on water and the Wells and others (1979) paper on soils. This publication is divided into three major parts (A, B, C) and an introductory chapter that provides discussions of fire regimes, fire severity and intensity, and fire related disturbances. Part A describes the nature of the soil resource, its importance, characteristics and the responses of soils to fire and the relationship of these features to ecosystem functioning and sustainability. Part A is divided into three main chapters (2, 3, and 4) that describe specific fire effects on the physical, chemical, and biological properties of the soil, respectively. Likewise, Part B discusses the basic hydrologic processes that are affected by fire, including the hydrologic cycle, water quality, and aquatic biology. It also contains three chapters which specifically discuss the effect of fire on the hydrologic cycle, water quality, and aquatic biology in chapters 5, 6, and 7, respectively. Part C has five chapters that cover a wide range of related topics. Chapter 8 analyzes the effects of fire on the hydrology and nutrient cycling of wetland ecosystems along with management concerns. The use of models to describe heat transfer throughout the ecosystem and erosional response models to fire are discussed in chapter 9. Chapter 10 deals with important aspects of watershed rehabilitation and implementation of the Federal Burned Area Emergency Rehabilitation (BAER) program. Chapter 11 directs the fire specialists and managers to important information sources including data bases, Web sites, textbooks, journals, and other sources of fire effects information. A summary of the important highlights of the book are provided in chapter 12. Last, a glossary of fire terms is included in the appendix. The material provided in each chapter has been prepared by individuals having specific expertise in a particular subject. This publication has been written as an information source text for personnel involved in fire suppression and management, planners, decisionmakers, land managers, public relations personnel, and technicians who routinely and occasionally are involved in fire suppression and using fire as a tool in ecosystem management. Because of widespread international interest in the previous and current "Rainbow Series" publications, the International System of Units (Systeme International d'Unites, SI), informally called the metric system (centimeters, cubic meters, grams), is used along with English units throughout the volume. In some instances one or the other units are used exclusively where conversions would be awkward or space does not allow presentation of both units.

Soil Water Repellency

Soil Water Repellency PDF Author: C.J. Ritsema
Publisher: Elsevier
ISBN: 0080523218
Category : Technology & Engineering
Languages : en
Pages : 359

Get Book Here

Book Description
It has become clear that soil water repellency is much more wide-spread than formerly thought. Water repellency has been reported in most continents of the world for varying land uses and climatic conditions. Soil water repellency often leads to severe runoff and erosion, rapid leaching of surface-applied agrichemicals, and losses of water and nutrient availability for crops. At present, no optimum management strategies exist for water repellent soils, focusing on minimizing environmental risks while maintaining crop production. The book starts with a historical overview of water repellency research, followed by seven thematic sections covering 26 research chapters. The first section discusses the origin, the second the assessment, and the third the occurrence and hydrological implications of soil water repellency. The fourth section is devoted to the effect of fire on water repellency, section five deals with the physics and modeling of flow and transport in water repellent soils, section six presents amelioration techniques and farming strategies to combat soil water repellency, and section seven concludes the book with an extensive bibliography on soil water repellency.

Wildland Fire in Ecosystems

Wildland Fire in Ecosystems PDF Author: United States Department of Agriculture
Publisher: CreateSpace
ISBN: 9781508890027
Category :
Languages : en
Pages : 260

Get Book Here

Book Description
This state-of-knowledge review about the effects of fire on soils and water can assist land and fire managers with information on the physical, chemical, and biological effects of fire needed to successfully conduct ecosystem management, and effectively inform others about the role and impacts of wildland fire. Chapter topics include the soil resource, soil physical properties and fire, soil chemistry effects, soil biology responses, the hydrologic cycle and water resources, water quality, aquatic biology, fire effects on wetland and riparian systems, fire effects models, and watershed rehabilitation.

Cumulative Watershed Effects of Fuel Management in the Western United States

Cumulative Watershed Effects of Fuel Management in the Western United States PDF Author: U.s. Department of Agriculture
Publisher: Createspace Independent Pub
ISBN: 9781480146433
Category : Nature
Languages : en
Pages : 306

Get Book Here

Book Description
Fire suppression in the last century has resulted in forests with excessive amounts of biomass, leading to more severe wildfires, covering greater areas, requiring more resources for suppression and mitigation, and causing increased onsite and offsite damage to forests and watersheds. Forest managers are now attempting to reduce this accumulated biomass by thinning, prescribed fire, and other management activities. These activities will impact watershed health, particularly as larger areas are treated and treatment activities become more widespread in space and in time. Management needs, laws, social pressures, and legal findings have underscored a need to synthesize what we know about the cumulative watershed effects of fuel management activities. To meet this need, a workshop was held in Provo, Utah, on April, 2005, with 45 scientists and watershed managers from throughout the United States. At that meeting, it was decided that two syntheses on the cumulative watershed effects of fuel management would be developed, one for the eastern United States, and one for the western United States. For the western synthesis, 14 chapters were defined covering fire and forests, machinery, erosion processes, water yield and quality, soil and riparian impacts, aquatic and landscape effects, and predictive tools and procedures. We believe these chapters provide an overview of our current understanding of the cumulative watershed effects of fuel management in the western United States. This document is the result of a major interdisciplinary effort to synthesize our understanding of the cumulative watershed effects of fuel management. This document is the product of more than 20 authors and 40 reviewers including scientists from four Forest Service Research Stations and numerous universities. Chapter topics include overviews of the effects of fuel management on both terrestrial and aquatic watershed processes.

Cumulative Watershed Effects of Fuel Management in the Western United States

Cumulative Watershed Effects of Fuel Management in the Western United States PDF Author: William J. Elliot
Publisher:
ISBN:
Category :
Languages : en
Pages : 299

Get Book Here

Book Description