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San Rafael Creek
San Rafael Creek is a watercourse in Marin County, California, United States that discharges to San Rafael Bay, a small embayment of the San Francisco Bay. The mouth of San Rafael Creek is a channelized estuary through an industrial area. San Rafael Creek has a designation under Federal Law Section 303(d) as impaired by diazinon, the principal pollutant causing impairment designations for streams discharging to San Pablo Bay, which is the northern arm of San Francisco Bay. In September 2007, the organization Save The Bay designated San Rafael Creek as one of the top ten "worst trash hot spot" waterways flowing into the San Francisco Bay. The channel portion of San Rafael Creek below the Grand Street Bridge is dredged on a regular maintenance schedule to keep the shallow draft channel navigable. Dredge spoils are disposed of at a site near Alcatraz Island. Most of the soils in the lower watershed are clays and bay mud, resulting in a low transmissivity of groundwater. Typical vert ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territories, nine Minor Outlying Islands, and 326 Indian reservations. The United States is also in free association with three Pacific Island sovereign states: the Federated States of Micronesia, the Marshall Islands, and the Republic of Palau. It is the world's third-largest country by both land and total area. It shares land borders with Canada to its north and with Mexico to its south and has maritime borders with the Bahamas, Cuba, Russia, and other nations. With a population of over 333 million, it is the most populous country in the Americas and the third most populous in the world. The national capital of the United States is Washington, D.C. and its most populous city and principal financial center is New York City. Paleo-Americ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rivers Of Marin County, California
A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases, a river flows into the ground and becomes dry at the end of its course without reaching another body of water. Small rivers can be referred to using names such as creek, brook, rivulet, and rill. There are no official definitions for the generic term river as applied to geographic features, although in some countries or communities a stream is defined by its size. Many names for small rivers are specific to geographic location; examples are "run" in some parts of the United States, "burn" in Scotland and northeast England, and "beck" in northern England. Sometimes a river is defined as being larger than a creek, but not always: the language is vague. Rivers are part of the water cycle. Water generally collects in a river from precipitation through a drainage basin from surface runoff and other sources such as groundwater recharge, springs, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salt Marsh Harvest Mouse
The salt marsh harvest mouse (''Reithrodontomys raviventris''), also known as the red-bellied harvest mouse, is an endangered rodent endemic to the San Francisco Bay Area salt marshes in California. The two distinct subspecies are both endangered and listed together on federal and state endangered-species lists. The northern subspecies (''R. r. halicoetes'') is lighter in color and inhabits the northern marshes of the bay, and the southern subspecies (''R. r. raviventris'') lives in the East and South Bay marshes. They are both quite similar in appearance to their congener species, the Western harvest mouse, ''R. megalotis'', to which they are not closely related. Genetic studies of the northern subspecies have revealed that the salt marsh harvest mouse is most closely related to the plains harvest mouse, ''R. montanus'', which occurs now in the Midwest. Its endangered designation is due to its limited range, historic decline in population and continuing threat of habitat loss du ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Watercourses In The San Francisco Bay Area
These watercourses (rivers, creeks, sloughs, etc.) in the San Francisco Bay Area are grouped according to the bodies of water they flow into. Tributaries are listed under the watercourses they feed, sorted by the elevation of the confluence so that tributaries entering nearest the sea appear first. Numbers in parentheses are Geographic Names Information System feature identifiers. Pacific Coast north of the Golden Gate Sonoma Coast Watercourses which feed into the Pacific Ocean in Sonoma County north of Bodega Head, listed from north to south: The Gualala River and its tributaries *Gualala River (253221) ** North Fork (229679) – flows from Mendocino County. ** South Fork (235010) ***Big Pepperwood Creek (219227) – flows from Mendocino County. ***Rockpile Creek (231751) – flows from Mendocino County. ***Buckeye Creek (220029) ****Little Creek (227239) ****North Fork Buckeye Creek (229647) *****Osser Creek (230143) *****Roy Creek (231987) ****Soda Springs Creek ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bird Migration
Bird migration is the regular seasonal movement, often north and south along a flyway, between breeding and wintering grounds. Many species of bird migrate. Migration carries high costs in predation and mortality, including from hunting by humans, and is driven primarily by the availability of food. It occurs mainly in the northern hemisphere, where birds are funneled onto specific routes by natural barriers such as the Mediterranean Sea or the Caribbean Sea. Migration of species such as storks, turtle doves, and swallows was recorded as many as 3,000 years ago by Ancient Greek authors, including Homer and Aristotle, and in the Book of Job. More recently, Johannes Leche began recording dates of arrivals of spring migrants in Finland in 1749, and modern scientific studies have used techniques including bird ringing and satellite tracking to trace migrants. Threats to migratory birds have grown with habitat destruction, especially of stopover and wintering sites, as wel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bedrock
In geology, bedrock is solid Rock (geology), rock that lies under loose material (regolith) within the crust (geology), crust of Earth or another terrestrial planet. Definition Bedrock is the solid rock that underlies looser surface material. An exposed portion of bedrock is often called an outcrop. The various kinds of broken and weathered rock material, such as soil and subsoil, that may overlie the bedrock are known as regolith. Engineering geology The surface of the bedrock beneath the soil cover (regolith) is also known as ''rockhead'' in engineering geology, and its identification by digging, drilling or geophysics, geophysical methods is an important task in most civil engineering projects. Superficial deposition (geology), deposits can be very thick, such that the bedrock lies hundreds of meters below the surface. Weathering of bedrock Exposed bedrock experiences weathering, which may be physical or chemical, and which alters the structure of the rock to leave ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sandstone
Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates) because they are the most resistant minerals to weathering processes at the Earth's surface. Like uncemented sand, sandstone may be any color due to impurities within the minerals, but the most common colors are tan, brown, yellow, red, grey, pink, white, and black. Since sandstone beds often form highly visible cliffs and other topographic features, certain colors of sandstone have been strongly identified with certain regions. Rock formations that are primarily composed of sandstone usually allow the percolation of water and other fluids and are porous enough to store large quantities, making them valuable aquifers and petroleum reservoirs. Quartz-bearing sandstone can be changed into quartzite through metamorphism, usually related to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Franciscan
The Franciscans are a group of related Mendicant orders, mendicant Christianity, Christian Catholic religious order, religious orders within the Catholic Church. Founded in 1209 by Italian Catholic friar Francis of Assisi, these orders include three independent orders for men (the Order of Friars Minor being the largest contemporary male order), orders for women religious such as the Order of Saint Clare, and the Third Order of Saint Francis open to male and female members. They adhere to the teachings and spiritual disciplines of the founder and of his main associates and followers, such as Clare of Assisi, Anthony of Padua, and Elizabeth of Hungary. Several smaller Franciscan spirituality in Protestantism, Protestant Franciscan orders exist as well, notably in the Anglican and Lutheran traditions (e.g. the Community of Francis and Clare). Francis began preaching around 1207 and traveled to Rome to seek approval from Pope Innocent III in 1209 to form a new religious order. The o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Groundwater
Groundwater is the water present beneath Earth's surface in rock and soil pore spaces and in the fractures of rock formations. About 30 percent of all readily available freshwater in the world is groundwater. A unit of rock or an unconsolidated deposit is called an aquifer when it can yield a usable quantity of water. The depth at which soil pore spaces or fractures and voids in rock become completely saturated with water is called the water table. Groundwater is recharged from the surface; it may discharge from the surface naturally at springs and seeps, and can form oases or wetlands. Groundwater is also often withdrawn for agricultural, municipal, and industrial use by constructing and operating extraction wells. The study of the distribution and movement of groundwater is hydrogeology, also called groundwater hydrology. Typically, groundwater is thought of as water flowing through shallow aquifers, but, in the technical sense, it can also contain soil moisture, perma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bay Mud
Bay mud consists of thick deposits of soft, unconsolidated silty clay, which is saturated with water; these soil layers are situated at the bottom of certain estuaries, which are normally in temperate regions that have experienced cyclical glacial cycles. Example locations are Cape Cod Bay, Chongming Dongtan Reserve in Shanghai, China, Banc d'Arguinpreserve in Mauritania, The Bristol Channel in the United Kingdom, Mandø Island in the Wadden Sea in Denmark, Florida Bay, San Francisco Bay, Bay of Fundy, Casco Bay, Penobscot Bay, and Morro Bay. Bay mud manifests low shear strength, high compressibility and low permeability, making it hazardous to build upon in seismically active regions like the San Francisco Bay Area. Typical bulk density of bay mud is approximately 1.3 grams per cubic centimetre. Bay muds often have a high organic content, consisting of decayed organisms at lower depths, but may also contain living creatures when they occur at the upper soil layer and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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