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35-664: McCarthy Road starts at the end of the Edgerton Highway in Chitina. The road is gravel-surfaced, and often very rough with many washboards and sharp turns. The route follows the railbed of the defunct Copper River and Northwestern Railway , and utilizes the spectacular Kuskulana Bridge, built in 1910, spanning 238 feet (73 m) high above the Kuskulana River at mile 17. It is one of two roads leading to Wrangell-St. Elias National Park and Preserve , though it

70-531: A GIS-ready format that can be used to estimate TIA value. The NLCD consistently quantifies the percent anthropogenic TIA for the NLCD at a 30-meter (a 900 m2) pixel resolution throughout the Nation. Within the data set, each pixel is quantified as having a TIA value that ranges from 0 to 100 percent. TIA estimates made with the NLCD impervious surface data set represent an aggregated TIA value for each pixel rather than

105-699: A PIMP value of 100%. This variable is used in the Flood Estimation Handbook . Homer and others (2007) indicate that about 76 percent of the conterminous United States is classified as having less than 1 percent impervious cover, 11 percent with impervious cover of 1 to 10 percent, 4 percent with an estimated impervious cover of 11 to 20 percent, 4.4 percent with an estimated impervious cover of 21 to 40 percent, and about 4.4 percent with an estimated impervious cover greater than 40 percent. The total impervious area (TIA), commonly referred to as impervious cover (IC) in calculations, can be expressed as

140-419: A TIA value for an individual impervious feature. For example, a two lane road in a grassy field has a TIA value of 100 percent, but the pixel containing the road would have a TIA value of 26 percent. If the road (equally) straddles the boundary of two pixels, each pixel would have a TIA value of 13 percent. The Data-quality analysis of the NLCD 2001 data set with manually delimited TIA sample areas indicates that

175-602: A chain of events that modifies urban air and water resources: The total coverage by impervious surfaces in an area, such as a municipality or a watershed , is usually expressed as a percentage of the total land area. The coverage increases with rising urbanization . In rural areas, impervious cover may only be one or two percent. In residential areas, coverage increases from about 10 percent in low-density subdivisions to over 50 percent in multifamily communities. In industrial and commercial areas, coverage rises above 70 percent. In regional shopping centers and dense urban areas, it

210-421: A dense, tight mass with an almost impervious surface ." It emphasizes the proper gradation of gravel—100% passing the 0.75 inches (19 mm)) sieve—to have fractured stone to "interlock" and 4–15% fines passing the #200 (75-μm) sieve to act as a binder and create cohesiveness in the gravel; substituting other binders, such as clay is also recommended. Alternately, one can incorporate reclaimed asphalt in

245-539: A fraction (from zero to one) or a percentage. There are many methods for estimating TIA, including the use of the National Land Cover Data Set (NLCD) with a Geographic information system (GIS), land-use categories with categorical TIA estimates, a generalized percent developed area, and relations between population density and TIA. The U.S. NLCD impervious surface data set may provide a high-quality nationally consistent land cover data set in

280-439: A half-and-half blend with quarried gravel to improve the binding properties of the surface. For existing washboarded surfaces, the bulletin recommends using a grader to cut and blend existing material to a depth one inch or more below the bottom of the washboarded segment and then add the new material into the top layer. Useful equipment includes a blade with rotating scarifying teeth or a replaceable bit-type cutting edge attached to

315-683: A natural impervious area during storms because these areas are a source of infiltration excess overland flows. Seemingly pervious areas that have been affected by development activities may act as impervious areas and generate infiltration excess overland flows. These stormflows may occur even during storms that do not meet precipitation volume or intensity criteria to produce runoff based on nominal infiltration rates. Developed pervious areas may behave like impervious areas because development and subsequent use tends to compact soils and reduce infiltration rates. For example, Felton and Lull (1963) measured infiltration rates for forest soils and lawns to indicate

350-399: A potential 80 percent reduction in infiltration as a result of development activities. Similarly, Taylor (1982) did infiltrometer tests in areas before and after suburban development and noted that topsoil alteration and compaction by construction activities reduced infiltration rates by more than 77 percent. This article incorporates public domain material from websites or documents of

385-468: A qualitative measure of the prevalence of different land covers that may act as natural impervious areas. Open water may act as a natural impervious area if direct precipitation is routed through the channel network and arrives as stormflow at the site of interest. Wetlands may act as a natural impervious area during storms when groundwater discharge and saturation overland flow are a substantial proportion of stormflow. Barren ground in riparian areas may act as

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420-484: A series of ripples, which occur with the passage of wheels rolling over unpaved roads at speeds sufficient to cause bouncing of the wheel on the initially unrippled surface and take on the appearance of a laundry washboard . Most studies of washboarding pertain to granular materials, including sand and gravel . However, other work suggests that the phenomenon may occur in material which has some binding of particles, e.g. clay-like soils . Highway department experts in

455-868: A substantial amount of surface runoff during small and large storms, but commonly are classified as pervious areas. These areas are not commonly considered as an important source of stormflow in most highway and urban runoff -quality studies, but may produce a substantial amount of stormflow. These natural impervious areas may include open water, wetlands , rock outcrops, barren ground (natural soils with low imperviousness), and areas of compacted soils . Natural impervious areas, depending on their nature and antecedent conditions, may produce stormflow from infiltration excess overland flow, saturation overland flow, or direct precipitation. The effects of natural impervious areas on runoff generation are expected to be more important in areas with low TIA than highly developed areas. The NLCD provides land-cover statistics that can be used as

490-415: A variety of granular and viscous, even fluid, materials. In the laboratory, washboarding has been studied for a range of parameters, including the thickness and grain size of the material for varied wheel sizes, shapes, and masses. Experiments produced ripples for each parameter, above a threshold speed, when the wheel (or blade) began to bounce. Experiments also show that the pattern can move either against

525-797: Is also estimated from impervious maps extracted through remote sensing . Remote sensing has been extensively utilized to detect impervious surfaces. Detection of impervious areas using deep learning in conjunction with satellite images has emerged as a transformative method in remote sensing and environmental monitoring . Deep learning algorithms, particularly convolutional neural networks (CNNs), have revolutionized our capacity to identify and quantify impervious surfaces from high-resolution satellite imagery. These models can automatically extract intricate spatial and spectral features, enabling them to discriminate between impervious and non-impervious surfaces with exceptional accuracy. Natural impervious areas are defined herein as land covers that can contribute

560-416: Is an important factor when considering drainage of water. It is calculated by measuring the percentage of a catchment area which is made up of impervious surfaces such as roads, roofs and other paved surfaces. An estimation of PIMP is given by PIMP = 6.4J^0.5 where J is the number of dwellings per hectare (Butler and Davies 2000). For example, woodland has a PIMP value of 10%, whereas dense commercial areas have

595-598: Is commonly used to estimate TIA manually by using maps. The Multi-Resolution Land Characteristics Consortium (MRLCC) defines a developed area as being covered by at least 30 percent of constructed materials ). Southard (1986) defined non-developed areas as natural, agricultural , or scattered residential development . He developed a regression equation to predict TIA using percent developed area (table 6-1). He developed his equation using logarithmic power function with data from 23 basins in Missouri . He noted that this method

630-629: Is in Unorganized Borough . Washboarding Washboarding or corrugation is the formation of periodic, transverse ripples in the surface of gravel and dirt roads . Washboarding occurs in dry, granular road material with repeated traffic, traveling at speeds above 8.0 kilometres per hour (5 mph). Washboarding creates an uncomfortable ride for the occupants of traversing vehicles and hazardous driving conditions for vehicles that travel too fast to maintain traction and control. Washboarding or corrugation of roads comprises

665-596: Is not part of the park, and gives access to the abandoned copper mines at Kennecott . The road does not actually lead all the way to Kennecott; visitors must cross the Kennecott River by a footbridge built in the 1990s. The road is not maintained during winter. The road was the inspiration for the 2004 book The Road to McCarthy: Around the World in Search of Ireland by Pete McCarthy . The entire route

700-506: Is over 90 percent. In the contiguous 48 states of the US, urban impervious cover adds up to 43,000 square miles (110,000 km ). Development adds 390 square miles (1,000 km ) annually. Typically, two-thirds of the cover is pavements and one-third is building roofs. Impervious surface coverage can be limited by restricting land use density (such as a number of homes per acre in a subdivision), but this approach causes land elsewhere (outside

735-627: The moldboard blade of the earth-moving equipment. Impervious surface Impervious surfaces are mainly artificial structures—such as pavements ( roads , sidewalks , driveways and parking lots , as well as industrial areas such as airports , ports and logistics and distribution centres , all of which use considerable paved areas) that are covered by water-resistant materials such as asphalt , concrete , brick , stone —and rooftops . Soils compacted by urban development are also highly impervious. Impervious surfaces are an environmental concern because their construction initiates

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770-520: The Nevada Department of Highways advocated mitigating corrugations with crushed pit-run gravel, using material 1 inch (25 mm) and smaller, including only the fines from crushing. Contemporaneous advice from Colorado was to use a well-graded gravel, not exceeding 1.25 inches (32 mm) and including 25–40% fines passing a 0.25-inch (6.4 mm) sieve, but not more than 5% passing a #10 (2.0-mm) sieve. The maintenance advice from Colorado

805-787: The Port of Long Beach has put extensive effort into capturing rainfall to minimize the cost of transportation from the mainland. Partly in response to recent criticism by municipalities , a number of concrete manufacturers such as CEMEX and Quikrete have begun producing permeable materials which partly mitigate the environmental impact of conventional impervious concrete. These new materials are composed of various combinations of naturally derived solids including fine to coarse-grained rocks and minerals , organic matter (including living organisms ), ice , weathered rock and precipitates , liquids (primarily water solutions ), and gases . The COVID-19 pandemic gave birth to proposals for radical change in

840-495: The accuracy of such estimates tend to improve with increasing drainage area as local variations are averaged out. Granato (2010) provides a table with 8 population-density relations from the literature and a new equation developed by using data from 6,255 stream basins in the USGS GAGESII dataset. Granato (2010) also provides four equations to estimate TIA from housing density, which is related to population density. TIA

875-955: The average error of predicted versus actual TIA may range from 8.8 to 11.4 percent. TIA estimates from land use are made by identifying land use categories for large blocks of land, summing the total area of each category, and multiplying each area by a characteristic TIA coefficient. Land use categories commonly are used to estimate TIA because areas with a common land use can be identified from field studies, from maps, from planning and zoning information, and from remote imagery. Land use coefficient methods commonly are used because planning and zoning maps that identify similar areas are, increasingly, available in GIS formats. Also, land use methods are selected to estimate potential effects of future development on TIA with planning maps that quantify projected changes in land use. There are substantial differences in actual and estimated TIA estimates from different studies in

910-513: The direction of motion or in the direction of motion. They also show that a passive, non-driving wheel suffices to create corrugations and that displacement of material, rather than ejection, is the dominant mechanism. Several articles about real-life washboarding on roads cite South Dakota Local Transportation Assistance Program (LTAP) Special Bulletin #29, “Dealing with Washboarding,” by Ken Skorseth. Those sources attribute washboarding to three causes: dry granular materials, vehicle speeds, and

945-411: The literature. Terms like low density and high density may differ in different areas. A residential density of one-half acre per house may be classified as high density in a rural area, medium density in a suburban area, and low density in an urban area. Granato (2010) provides a table with TIA values for different land-use categories from 30 studies in the literature. The percent developed area (PDA)

980-399: The mid-1920s were aware that traffic volume and speed were primary causes of corrugations on gravel roads and cited the role of drive wheels tossing material as a factor. Laboratory-scale studies of the phenomenon typically employ a wheel or a blade, which is towed behind a pivot point, tracing a circular path through a pan of the material under examination. These studies have investigated

1015-600: The organisation of the city, being the drastic reduction of the presence of impermeable surfaces and the recovery of the permeability of the soil one of the elements of the Manifesto for the Reorganisation of the city, published in Barcelona by architecture and urban theorist Massimo Paolini and signed by 160 academics and 350 architects. The percentage imperviousness, commonly referred to as PIMP in calculations,

1050-434: The population in an area of interest and using regression equations to calculate the associated TIA. Population-density data are used because nationally consistent census-block data are available in GIS formats for the entire United States. Population-density methods also can be used for predicting potential effects of future development. Although there may be substantial variation in relations between population density and TIA

1085-421: The quality of the granular material. Other factors cited include vehicle speed, traffic volume, and hard acceleration or braking. The sources also claim that light vehicles are more likely to cause washboarding than heavy trucks. Highway department guidance suggests that choice of gravel can be key to mitigating washboarding. They cite "sieve analysis" tests that use a series of screens or sieves to characterize

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1120-413: The sizes of particles contained within a gravel sample. Highway department guidance suggests a range of particle sizes from stones that are in the 1-inch (25 mm) range, mixed with progressively finer particles to include a small fraction of fine particles that bind the larger particles together. They also mention the role of equipment that can re-blend and smooth surfaces that have corrugated. In 1925,

1155-463: The subdivision) to be developed, to accommodate the growing population. (See urban sprawl . ) Alternatively, urban structures can be built differently to make them function more like naturally pervious soils; examples of such alternative structures are porous pavements , green roofs and infiltration basins . Rainwater from impervious surfaces can be collected in rainwater tanks and used in place of main water. The island of Catalina located West of

1190-437: Was advantageous because large basins could quickly be delineated and TIA estimated manually from available maps. Granato (2010) developed a regression equation by using data from 262 stream basins in 10 metropolitan areas of the conterminous United States with drainage areas ranging from 0.35 to 216 square miles and PDA values ranging from 0.16 to 99.06 percent. TIA also is estimated from population density data by estimating

1225-407: Was to drag or grade the road frequently, applying light volumes of new gravel with minimal sand content and providing good drainage with a crown. The same source advises reduction of traffic speed. Guidance based on South Dakota LTAP Special Bulletin #29 and FHWA guidance (2000) from the same source suggests that the surface gravel "should be a blend of stone, sand and fines that will compact into

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