Water crises-defined as significant declines in water quality and quantity-top the global risks l... more Water crises-defined as significant declines in water quality and quantity-top the global risks list compiled by the World Economic Forum (2015) that have the greatest potential impacts on society. Vegetation fires are amongst the most hydrologically significant landscape disturbances (Ebel & Mirus, 2014) and affect~4% of the global vegetated land surface annually (Giglio, Randerson, & van der Werf, 2013). Fire-prone or fire-managed ecosystems (forests, grass-, and peatlands) also provide~60% of the water supply for the world's 100 largest cities (Martin, 2016). Accordingly, fire is increasingly acknowledged as a serious threat to water supply globally (Martin, 2016; Robinne et al., 2016). Whilst the global area burned declined by~20% over the last two decades mainly due to agricultural expansion (Andela et al., 2017), many areas critical for water supply are exposed to increasing fire risk (Doerr & Santin, 2016; Sankey et al., 2017). This is due to increases in fire weather severity (Flannigan et al., 2013) and extended fire season in many regions (Westerling, Hidalgo, Cayan, & Swetnam, 2006), as well as fuel build-up due to fire suppression, afforestation, land abandonment, and a trend towards more extensive fires (Doerr & Santin, 2016). A substantial body of hydrological research exists on fire impacts on soil-, hillslope-and, to a lesser extent, catchment-scale processes with a focus on infiltration, runoff, erosion, and water yield
This study measured runoff and sediment concentration from the tire track and from the non-tire t... more This study measured runoff and sediment concentration from the tire track and from the non-tire track to determine infiltration, interrill erodibility, and vegetative cover impacts of reopening an abandoned forest road. Runoff was lowest on the non-track portion of the abandoned road and highest on the reopened road. Sediment concentrations were significantly higher on the reopened road. Increased sediment concentrations were attributed to decreased vegetative cover, rather than traffic-induced changes in the physical soil properties of the reopened road. Thirty years of no traffic and vegetation regrowth was not sufficient to allow recovery of infiltration to values similar to an undisturbed forest. The study also found a significant dynamic behavior in interrill erodibility with respect to antecedent rainfall. Forest road erosion models that fail to account for this change will overestimate sediment yields.
Soil quality standards and guidelines of the USDA Forest Service were some of the ®rst in the wor... more Soil quality standards and guidelines of the USDA Forest Service were some of the ®rst in the world to be developed to evaluate changes in forest soil productivity and sustainability after harvesting and site preparation. International and national development of criteria and indicators for maintenance of soil productivity make it imperative to have adequate threshold variables within the USDA Forest Service. In the Paci®c Northwest, soils range from ®ne-textured Andisols to coarse-textured skeletal Inceptisols. Forest types encompass the highly productive coastal rain forest to marginally productive, dry, cold sites in the interior mountains. Constant values to detect detrimental disturbances within the soil quality guidelines are routinely applied across diverse soils and timber types and include diagnostic criteria for evaluating management-caused changes to soil productivity. Research information from short-or long-term research studies supporting the applicability of disturbance criteria is often lacking, or is available from a limited number of sites which have relatively narrow climatic and soil ranges. In this paper we calculated changes in soil carbon, nitrogen, erosion, and cation exchange capacity using threshold variables from the Regional USDA Forest Service Soil Guidelines to assess their applicability across diverse landscapes. Soils were selected from a climatic and elevational gradient in the Paci®c Northwest. Application of selected USDA Forest Service standards indicate that blanket threshold variables applied over disparate soils do not adequately account for nutrient distribution within the pro®le or forest¯oor depth. These types of guidelines should be continually re®ned to re¯ect pre-disturbance conditions and site-speci®c information. Published by Elsevier Science B.V.
Introductory paragraphs: Sprinkler irrigation is a versatile means of applying water to any crop,... more Introductory paragraphs: Sprinkler irrigation is a versatile means of applying water to any crop, soil, and topographic condition. It is popular because (1) surface ditches are not necessary, (2) prior land preparation is minimal, and (3) pipes are easily transported and provide no obstructions to farm operations when irrigation is not needed. According to the "2000 Irrigation Survey" in Irrigation Journal (2001), about 12 500 000 ha or 49.9% of the irrigated land in the U.S. is irrigated with sprinkler systems. Sprinkling is suitable for sandy soils or other soil and topographic conditions where surface irrigation may be inefficient or expensive, or where erosion may be particularly hazardous. Low rates and amounts of water may be applied, such as are required for seed germination, frost protection, delay of fruit budding, and cooling of crops in hot weather. Fertilizers and soil amendments may be dissolved in the water and applied through the irrigation system. The major concerns of sprinkler systems are investment costs and labor requirements (Chapter 15).
Introductory paragraphs: Soil erosion by water can be a natural process or caused by human distur... more Introductory paragraphs: Soil erosion by water can be a natural process or caused by human disturbance. Natural soil erosion by water is often referred to as geological erosion. This includes soil-forming as well as soil-eroding processes that maintain the soil in a favorable balance suitable for the growth of most plants. This long-time eroding process caused most of the present topographic features, such as canyons, stream channels, and valleys. In contrast, accelerated erosion associated with human disturbances is one of the most important agricultural and natural resource management problems in the world. Human disturbances include agricultural, mining, forestry, and construction activities. Disturbances due to human or animal influences can reduce vegetative cover and compact soil. Following disturbances, runoff and soil erosion rates increase well above geological levels. Accelerated erosion can lead to a loss of soil productivity and adversely affect surface water quality and flood flows. Water erosion is the detachment and transport of soil from the land by water, including runoff from melted snow and ice. It reduces soil productivity and is a primary source of sediment that pollutes streams and fills reservoirs. In the 1970s, soil erosion estimates in the United States were as high as 4 billion Mg of soil annually. This amount declined to about 2 billion Mg by 1997, mainly due to the increased use of conservation or Best Management Practices (Iivari and Kertis, 2001), and is unlikely to change greatly from that level. Since the early 1970s, greater emphasis has been given to erosion as a contributor to nonpoint source pollution. In this chapter, "nonpoint source" refers to erosion from the land surface rather than from channels and gullies. Eroded sediment can carry nutrients, particularly phosphates, to waterways, and contribute to eutrophication of lakes and streams. Adsorbed pesticides, microorganisms, and hormones are also carried with eroded sediments, adversely affecting surface water quality.
Introductory paragraphs: As described in Chapters 12 and 13, poor internal drainage, high water t... more Introductory paragraphs: As described in Chapters 12 and 13, poor internal drainage, high water tables, and inadequate surface drainage combine to produce waterlogged soils. Although some of these areas may be classified as wetlands, significant land resources experience wet soil conditions for brief periods during the year that limit their maximum productivity but not to a degree that creates wetland conditions. Increases in world population and the need for food, clothing, and housing will require that additional land resources are available to meet our needs without negatively affecting the environment. For thousands of years, naturally wet areas have been drained with ditches, canals, and, more recently, buried pipe to develop sites for recreation, construction, and agriculture. The practice of controlling or altering the position of the water table with ditches or subsurface pipes is called water table management (WTM).
Lowvolume roads aremvgnid as oneof thephayaolurrs of xdi-management (Figure 1). On roads. the con... more Lowvolume roads aremvgnid as oneof thephayaolurrs of xdi-management (Figure 1). On roads. the construction, maintenante. men1 m m y watersheds. ?bc ~l l k m ham canied out on the and level of traftic all affect the erosion me.-1s of the oompler soil a s i o n pesses occuuing on low-volume A number of components makeup aroad, and the design and manman '' years'Anm-ew of wiresearch sumwi m agement of each component may Mumce the erosion oftheroad or IhG results of numcxous past and ongoing field and computer m-ng snrdies on mad and effects of road design on load delivery of s u l i fmmthe road to a stream system. Figure 2 preme authorshamfound e b l m i n e a n d-lmhecffmts on sents ffie main mad components that affect soil erosion The deslgn &are oiim washadowcd by heeffe&oi.nnting. ~& & i l nosion and management of a road determine the flow path lhat water follows on mads is from corlfenmcd flow in ruts a dilches. Adding gravel to exit the road. All roads are designed to have a compacted foundai n c~h Y~~n d U~~r Y ~~c e s~o n. R d e m s b * m f~ tion and to shed water. he main &oscsectional shapes of roads are canalso bedEdcsvdbyrrducio~h~orhyremovingroadc.m e r o m insloping, or outslopmg (Figure 2). On some forest roads, au~orsare&veloping apphtior~sof the WaterErosionRediaianFmjst model as u9cT9cTfdmm. ROAD EROSION AND SEDIMENTATION PROCESSES Soil erosion and sedimentation are the products of complex intqactions among soils, climate, K~h y , and s u d a~v e~ or
High-intensity wildfires are one of the leading causes of severe soil erosion in western U.S. wat... more High-intensity wildfires are one of the leading causes of severe soil erosion in western U.S. watersheds. This erosion can lead to disruptive deposits of sediment in reservoirs and water supply systems. Fuel treatments such as controlled burns and forest thinning can reduce wildfire intensity and help preserve topsoil. But while these treatments are generally much less expensive than firefighting, property loss, and sediment removal, there are limited funds available for controlled burns and forest thinning. For this reason, land managers can benefit from estimating the erosion potential of high-intensity wildfires in order to decide where to focus fuel reduction efforts. To help forest managers prioritize forest fuel reduction decisions, scientists from the Rocky Mountain Research Station and other agencies and organizations have developed several modeling tools that predict fire risk and erosion potential in and around watersheds. These tools, which include FSim, FlamMap, and WEPP (Water Erosion Prediction Project), are helping land managers preserve long-term forest health and preserve water supply and access in the western United States. By helping to quantify the connection between forest management and water supply protection, these tools are helping land managers cultivate stakeholder support for forest management efforts. Erosion from steep, denuded hillsides after wildfires can clog nearby streams with sediment, reducing water quality and creating challenges for downstream municipal water systems (image from the
Water crises-defined as significant declines in water quality and quantity-top the global risks l... more Water crises-defined as significant declines in water quality and quantity-top the global risks list compiled by the World Economic Forum (2015) that have the greatest potential impacts on society. Vegetation fires are amongst the most hydrologically significant landscape disturbances (Ebel & Mirus, 2014) and affect~4% of the global vegetated land surface annually (Giglio, Randerson, & van der Werf, 2013). Fire-prone or fire-managed ecosystems (forests, grass-, and peatlands) also provide~60% of the water supply for the world's 100 largest cities (Martin, 2016). Accordingly, fire is increasingly acknowledged as a serious threat to water supply globally (Martin, 2016; Robinne et al., 2016). Whilst the global area burned declined by~20% over the last two decades mainly due to agricultural expansion (Andela et al., 2017), many areas critical for water supply are exposed to increasing fire risk (Doerr & Santin, 2016; Sankey et al., 2017). This is due to increases in fire weather severity (Flannigan et al., 2013) and extended fire season in many regions (Westerling, Hidalgo, Cayan, & Swetnam, 2006), as well as fuel build-up due to fire suppression, afforestation, land abandonment, and a trend towards more extensive fires (Doerr & Santin, 2016). A substantial body of hydrological research exists on fire impacts on soil-, hillslope-and, to a lesser extent, catchment-scale processes with a focus on infiltration, runoff, erosion, and water yield
This study measured runoff and sediment concentration from the tire track and from the non-tire t... more This study measured runoff and sediment concentration from the tire track and from the non-tire track to determine infiltration, interrill erodibility, and vegetative cover impacts of reopening an abandoned forest road. Runoff was lowest on the non-track portion of the abandoned road and highest on the reopened road. Sediment concentrations were significantly higher on the reopened road. Increased sediment concentrations were attributed to decreased vegetative cover, rather than traffic-induced changes in the physical soil properties of the reopened road. Thirty years of no traffic and vegetation regrowth was not sufficient to allow recovery of infiltration to values similar to an undisturbed forest. The study also found a significant dynamic behavior in interrill erodibility with respect to antecedent rainfall. Forest road erosion models that fail to account for this change will overestimate sediment yields.
Soil quality standards and guidelines of the USDA Forest Service were some of the ®rst in the wor... more Soil quality standards and guidelines of the USDA Forest Service were some of the ®rst in the world to be developed to evaluate changes in forest soil productivity and sustainability after harvesting and site preparation. International and national development of criteria and indicators for maintenance of soil productivity make it imperative to have adequate threshold variables within the USDA Forest Service. In the Paci®c Northwest, soils range from ®ne-textured Andisols to coarse-textured skeletal Inceptisols. Forest types encompass the highly productive coastal rain forest to marginally productive, dry, cold sites in the interior mountains. Constant values to detect detrimental disturbances within the soil quality guidelines are routinely applied across diverse soils and timber types and include diagnostic criteria for evaluating management-caused changes to soil productivity. Research information from short-or long-term research studies supporting the applicability of disturbance criteria is often lacking, or is available from a limited number of sites which have relatively narrow climatic and soil ranges. In this paper we calculated changes in soil carbon, nitrogen, erosion, and cation exchange capacity using threshold variables from the Regional USDA Forest Service Soil Guidelines to assess their applicability across diverse landscapes. Soils were selected from a climatic and elevational gradient in the Paci®c Northwest. Application of selected USDA Forest Service standards indicate that blanket threshold variables applied over disparate soils do not adequately account for nutrient distribution within the pro®le or forest¯oor depth. These types of guidelines should be continually re®ned to re¯ect pre-disturbance conditions and site-speci®c information. Published by Elsevier Science B.V.
Introductory paragraphs: Sprinkler irrigation is a versatile means of applying water to any crop,... more Introductory paragraphs: Sprinkler irrigation is a versatile means of applying water to any crop, soil, and topographic condition. It is popular because (1) surface ditches are not necessary, (2) prior land preparation is minimal, and (3) pipes are easily transported and provide no obstructions to farm operations when irrigation is not needed. According to the "2000 Irrigation Survey" in Irrigation Journal (2001), about 12 500 000 ha or 49.9% of the irrigated land in the U.S. is irrigated with sprinkler systems. Sprinkling is suitable for sandy soils or other soil and topographic conditions where surface irrigation may be inefficient or expensive, or where erosion may be particularly hazardous. Low rates and amounts of water may be applied, such as are required for seed germination, frost protection, delay of fruit budding, and cooling of crops in hot weather. Fertilizers and soil amendments may be dissolved in the water and applied through the irrigation system. The major concerns of sprinkler systems are investment costs and labor requirements (Chapter 15).
Introductory paragraphs: Soil erosion by water can be a natural process or caused by human distur... more Introductory paragraphs: Soil erosion by water can be a natural process or caused by human disturbance. Natural soil erosion by water is often referred to as geological erosion. This includes soil-forming as well as soil-eroding processes that maintain the soil in a favorable balance suitable for the growth of most plants. This long-time eroding process caused most of the present topographic features, such as canyons, stream channels, and valleys. In contrast, accelerated erosion associated with human disturbances is one of the most important agricultural and natural resource management problems in the world. Human disturbances include agricultural, mining, forestry, and construction activities. Disturbances due to human or animal influences can reduce vegetative cover and compact soil. Following disturbances, runoff and soil erosion rates increase well above geological levels. Accelerated erosion can lead to a loss of soil productivity and adversely affect surface water quality and flood flows. Water erosion is the detachment and transport of soil from the land by water, including runoff from melted snow and ice. It reduces soil productivity and is a primary source of sediment that pollutes streams and fills reservoirs. In the 1970s, soil erosion estimates in the United States were as high as 4 billion Mg of soil annually. This amount declined to about 2 billion Mg by 1997, mainly due to the increased use of conservation or Best Management Practices (Iivari and Kertis, 2001), and is unlikely to change greatly from that level. Since the early 1970s, greater emphasis has been given to erosion as a contributor to nonpoint source pollution. In this chapter, "nonpoint source" refers to erosion from the land surface rather than from channels and gullies. Eroded sediment can carry nutrients, particularly phosphates, to waterways, and contribute to eutrophication of lakes and streams. Adsorbed pesticides, microorganisms, and hormones are also carried with eroded sediments, adversely affecting surface water quality.
Introductory paragraphs: As described in Chapters 12 and 13, poor internal drainage, high water t... more Introductory paragraphs: As described in Chapters 12 and 13, poor internal drainage, high water tables, and inadequate surface drainage combine to produce waterlogged soils. Although some of these areas may be classified as wetlands, significant land resources experience wet soil conditions for brief periods during the year that limit their maximum productivity but not to a degree that creates wetland conditions. Increases in world population and the need for food, clothing, and housing will require that additional land resources are available to meet our needs without negatively affecting the environment. For thousands of years, naturally wet areas have been drained with ditches, canals, and, more recently, buried pipe to develop sites for recreation, construction, and agriculture. The practice of controlling or altering the position of the water table with ditches or subsurface pipes is called water table management (WTM).
Lowvolume roads aremvgnid as oneof thephayaolurrs of xdi-management (Figure 1). On roads. the con... more Lowvolume roads aremvgnid as oneof thephayaolurrs of xdi-management (Figure 1). On roads. the construction, maintenante. men1 m m y watersheds. ?bc ~l l k m ham canied out on the and level of traftic all affect the erosion me.-1s of the oompler soil a s i o n pesses occuuing on low-volume A number of components makeup aroad, and the design and manman '' years'Anm-ew of wiresearch sumwi m agement of each component may Mumce the erosion oftheroad or IhG results of numcxous past and ongoing field and computer m-ng snrdies on mad and effects of road design on load delivery of s u l i fmmthe road to a stream system. Figure 2 preme authorshamfound e b l m i n e a n d-lmhecffmts on sents ffie main mad components that affect soil erosion The deslgn &are oiim washadowcd by heeffe&oi.nnting. ~& & i l nosion and management of a road determine the flow path lhat water follows on mads is from corlfenmcd flow in ruts a dilches. Adding gravel to exit the road. All roads are designed to have a compacted foundai n c~h Y~~n d U~~r Y ~~c e s~o n. R d e m s b * m f~ tion and to shed water. he main &oscsectional shapes of roads are canalso bedEdcsvdbyrrducio~h~orhyremovingroadc.m e r o m insloping, or outslopmg (Figure 2). On some forest roads, au~orsare&veloping apphtior~sof the WaterErosionRediaianFmjst model as u9cT9cTfdmm. ROAD EROSION AND SEDIMENTATION PROCESSES Soil erosion and sedimentation are the products of complex intqactions among soils, climate, K~h y , and s u d a~v e~ or
High-intensity wildfires are one of the leading causes of severe soil erosion in western U.S. wat... more High-intensity wildfires are one of the leading causes of severe soil erosion in western U.S. watersheds. This erosion can lead to disruptive deposits of sediment in reservoirs and water supply systems. Fuel treatments such as controlled burns and forest thinning can reduce wildfire intensity and help preserve topsoil. But while these treatments are generally much less expensive than firefighting, property loss, and sediment removal, there are limited funds available for controlled burns and forest thinning. For this reason, land managers can benefit from estimating the erosion potential of high-intensity wildfires in order to decide where to focus fuel reduction efforts. To help forest managers prioritize forest fuel reduction decisions, scientists from the Rocky Mountain Research Station and other agencies and organizations have developed several modeling tools that predict fire risk and erosion potential in and around watersheds. These tools, which include FSim, FlamMap, and WEPP (Water Erosion Prediction Project), are helping land managers preserve long-term forest health and preserve water supply and access in the western United States. By helping to quantify the connection between forest management and water supply protection, these tools are helping land managers cultivate stakeholder support for forest management efforts. Erosion from steep, denuded hillsides after wildfires can clog nearby streams with sediment, reducing water quality and creating challenges for downstream municipal water systems (image from the
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