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29-594: The River Pang is a small chalk stream river in the west of the English county of Berkshire , and a tributary of the River Thames . It runs for approximately 23 kilometres (14 mi) from its source near the village of Compton to its confluence with the Thames in the village of Pangbourne . The river, and its water voles , are thought to have inspired author Kenneth Grahame 's character Ratty and his book The Wind in

58-426: A few tens of kilometers of their source outcrops. Gravel is deposited as gravel blankets or bars in stream channels; in alluvial fans ; in near-shore marine settings, where the gravel is supplied by streams or erosion along the coast; and in the deltas of swift-flowing streams. The upper Mississippi embayment contains extensive chert gravels thought to have their origin less than 100 miles (160 km) from

87-644: A high hydraulic conductivity , sometimes reaching above 1 cm/s. Most gravel is derived from disintegration of bedrock as it weathers . Quartz is the most common mineral found in gravel, as it is hard, chemically inert, and lacks cleavage planes along which the rock easily splits. Most gravel particles consist of multiple mineral grains, since few rocks have mineral grains coarser than about 8 millimeters (0.31 in) in size. Exceptions include quartz veins , pegmatites , deep intrusions , and high-grade metamorphic rock . The rock fragments are rapidly rounded as they are transported by rivers , often within

116-793: A result of sedimentary and erosive geological processes; it is also produced in large quantities commercially as crushed stone . Gravel is classified by particle size range and includes size classes from granule - to boulder -sized fragments. In the Udden-Wentworth scale gravel is categorized into granular gravel (2–4 mm or 0.079–0.157 in) and pebble gravel (4–64 mm or 0.2–2.5 in). ISO 14688 grades gravels as fine, medium, and coarse, with ranges 2–6.3 mm (0.079–0.248 in) for fine and 20–63 mm (0.79–2.48 in) for coarse. One cubic metre of gravel typically weighs about 1,800 kg (4,000 lb), or one cubic yard weighs about 3,000 lb (1,400 kg). Gravel

145-464: A temporary reservoir by regulating the amount of water supplied to the springs. This is why many chalk streams in the UK have stable flow regimes that vary only slightly over time. The temperature of the emerging surface water is fairly stable and rarely deviates from 10 °C (50 °F). On cold winter mornings, water vapour from the relatively warm stream condenses in the cold air above to form fog. Chalk

174-414: Is an important commercial product, with a number of applications. Almost half of all gravel production is used as aggregate for concrete . Much of the rest is used for road construction, either in the road base or as the road surface (with or without asphalt or other binders.) Naturally occurring porous gravel deposits have a high hydraulic conductivity , making them important aquifers . Colloquially,

203-478: Is rather isolated, penetrated only by narrow country lanes. Because of this isolation, the valley has not become the residential commuter area that is much of Berkshire, and is still largely agricultural. The Pang contains American signal crayfish , which have displaced the native white-clawed crayfish species. The Berks, Bucks and Oxon Wildlife Trust owns a nature reserve straddling the Pang at Moor Copse, close to

232-480: Is slightly soluble in rainwater because rain is naturally slightly acidic . The products of chalk weathering are dissolved in rainwater and are transported in stream flow. Chalk streams transport little suspended material (unlike most rivers), but are considered " mineral -rich" due to the dissolved calcium and carbonate ions . The surface water of chalk streams is commonly described as "gin clear". The channel bed consists of angular flint gravel derived from

261-534: Is sometimes distinguished from rubble, which is loose rock particles in the same size range but angular in shape. The Udden-Wentworth scale , widely used by geologists in the US, defines granular gravel as particles with a size from 2 to 4 mm (0.079 to 0.157 in) and pebble gravel as particles with a size from 4 to 64 mm (0.16 to 2.52 in). This corresponds to all particles with sizes between coarse sand and cobbles . The U.S. Department of Agriculture and

290-405: Is widely and plentifully distributed, mostly as river deposits, river flood plains, and glacial deposits, so that environmental considerations and quality dictate whether alternatives, such as crushed stone , are more economical. Crushed stone is already displacing natural gravel in the eastern United States, and recycled gravel is also becoming increasingly important. The word gravel comes from

319-663: The North Kent Marshes ( Charles Dickens 's Great Expectations ) and the River Pang. The Environment Agency measures the water quality of the river systems in England. Each is given an overall ecological status, which may be one of five levels: high, good, moderate, poor and bad. There are several components that are used to determine this, including biological status, which looks at the quantity and varieties of invertebrates , angiosperms and fish, and chemical status, which compares

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348-702: The Old French gravele or gravelle . Different varieties of gravel are distinguished by their composition, origin, and use cases. Types of gravel include: In locales where gravelly soil is predominant, plant life is generally more sparse. This is due to the inferior ability of gravels to retain moisture, as well as the corresponding paucity of mineral nutrients, since finer soils that contain such minerals are present in smaller amounts. Sediments containing over 30% gravel that become lithified into solid rock are termed conglomerate . Conglomerates are widely distributed in sedimentary rock of all ages, but usually as

377-540: The River Thames , River Lea and River Colne ): Chalk streams of the Yorkshire Wolds : Chalk streams of Lincolnshire : There are several chalk streams in the Lincolnshire Wolds including Chalk streams of Kent: Chalk streams of Norfolk: Chalk streams of Suffolk: Gravel Gravel ( / ˈ ɡ r æ v əl / ) is a loose aggregation of rock fragments . Gravel occurs naturally on Earth as

406-817: The Soil Science Society of America define gravel as particles from 2 to 80 mm (0.079 to 3.150 in) in size, while the German scale (Atterburg) defines gravel as particles from 2 to 200 mm (0.079 to 7.874 in) in size. The U.S. Army Corps of Engineers defines gravel as particles under 3 in (76 mm) in size that are retained by a number 4 mesh, which has a mesh spacing of 4.76 mm (0.187 in). ISO 14688 for soil engineering grades gravels as fine, medium, and coarse with ranges 2 mm to 6.3 mm to 20 mm to 63 mm. The bulk density of gravel varies from 1,460 to 1,920 kg/m (2,460 to 3,240 lb/cu yd). Natural gravel has

435-426: The 210 rivers classified as chalk streams globally, 160 are in England. A list of chalk streams in England gives a total of 224. Chalk is a highly porous and permeable rock, and rain falling onto chalk topography percolates directly into the ground, where the chalk layer acts as an aquifer . The groundwater flows through the chalk bedrock, re-emerging lower down the slope in springs . The chalk acts as

464-403: The Pang, Kennet and Lambourn Valleys. ISBN   978-09543597-2-0 . 51°29′10″N 1°05′17″W  /  51.486°N 1.088°W  / 51.486; -1.088 Chalk stream The beds of the rivers are generally composed of clean, compacted gravel and flints , which are good spawning areas for Salmonidae fish species. Since they are fed primarily by aquifers ,

493-490: The U.S., with a total value of about $ 12.6 billion. Some 960 million tons of construction sand and gravel were produced. This greatly exceeds production of industrial sand and gravel (68 million tons), which is mostly sand rather than gravel. It is estimated that almost half of construction sand and gravel is used as aggregate for concrete . Other important uses include in road construction, as road base or in blacktop ; as construction fill; and in myriad minor uses. Gravel

522-399: The UK has caused the chalk streams to dry up. This has caused ecological damage and stagnant sewage that flows through the rivers and increasing phosphate levels. Although chalk streams are generally watercourses originating from chalk hills, including winterbournes , streams, and rivers, the term chalk stream is used even for larger rivers, which would normally be considered too large for

551-449: The Willows . The river's source is normally near the village of Compton , although the exact location varies depending on rainfall levels. In times of high rainfall it can be traced back to Farnborough , some four miles to the west-north-west, whilst at other times it may be as far downstream as the outfall from Hampstead Norreys sewage works . From Compton the Pang flows south through

580-514: The best conditions for fly fishing , and most specifically, dry fly fishing . The chalk streams hold a good number of wild salmonid fish species such as the brown trout ( Salmo trutta ), and grayling ( Thymallus thymallus ). In addition to these there are also considerable numbers of stocked brown trout and stocked rainbow trout ( Oncorhynchus mykiss ). The rich invertebrate life and characteristic transparent shallow water make chalk rivers and streams particularly suited to fly fishing. Many of

609-610: The chalk stream springs are also used as sites for watercress production, due to the constant temperature and clean, alkaline , mineral-rich spring water. The Mid Hants Watercress Railway in Hampshire is so named on account of its use for transporting watercress to London from local chalk streams. A number of the chalk aquifers and associated groundwater sources related to chalk streams and rivers are used for water abstraction by local and national water utility companies. The over-abstracting of chalk streams by private water companies in

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638-453: The concentrations of various chemicals against known safe concentrations. Chemical status is rated good or fail. Water quality of the River Pang in 2019: The river is named after a man, thought to be an early Saxon chieftain, or tribe called Pǣga who lived there in the post-Roman era. Greenaway, Dick (2007). Around the Valley of the Pang . Dorcas Ward (illus.). Theale, Reading: Friends of

667-436: The flow rate, mineral content and temperature range of chalk streams exhibit less seasonal variation than other rivers. They are mildly alkaline and contain high levels of nitrate , phosphate , potassium and silicate . In addition to algae and diatoms , the streams provide a suitable habitat for macrophytes (including water crowfoot ) and oxygen levels are generally supportive of coarse fish populations. Of

696-470: The natural flint deposits found embedded within the chalk geology that contains relatively low amounts of clay and silt deposits. The unique characteristics of chalk stream ecology are due to stable temperature and flow regimes combined with highly transparent water and lack of sand grade sediment particles. The chalk streams have been intensively managed for many generations. In the 20th and 21st centuries, much of that management has been aimed at producing

725-483: The periphery of the embayment. It has been suggested that wind-formed ( aeolian ) gravel "megaripples" in Argentina have counterparts on the planet Mars . Gravel is a major basic raw material in construction . Sand is not usually distinguished from gravel in official statistics, but crushed stone is treated as a separate category. In 2020, sand and gravel together made up 23% of all industrial mineral production in

754-715: The term stream . The Somme in northern France is a chalk stream on a larger scale. Winterbournes are known by different names depending on region: Chalk streams of the Southern England Chalk Formation in Berkshire , Hampshire , Wiltshire , Dorset and the Isle of Wight : Chalk streams of the Southern England Chalk Formation in the Chiltern Hills , Hertfordshire and Surrey (tributaries of

783-536: The term gravel is often used to describe a mixture of different size pieces of stone mixed with sand and possibly some clay. The American construction industry distinguishes between gravel (a natural material) and crushed stone (produced artificially by mechanical crushing of rock.) The technical definition of gravel varies by region and by area of application. Many geologists define gravel simply as loose rounded rock particles over 2 mm (0.079 in) in diameter, without specifying an upper size limit. Gravel

812-801: The village of Tidmarsh. A 29 ha (72-acre) extension to the nature reserve, in the area that is believed to have inspired Kenneth Grahame's work, was purchased in December 2006. In August 2007 a coalition of the WWF , the National Trust , the RSPB and others called on the British government to adopt their Blueprint for Water. To publicize their campaign they highlighted the dangers to sites well known through literature such as The Lake District ( Arthur Ransome 's Swallows and Amazons and Beatrix Potter 's Mrs Tiggy-Winkle ),

841-495: The villages of Hampstead Norreys and Frilsham , before turning east to flow through the villages of Bucklebury , Stanford Dingley and Bradfield . To the east of Bradfield the Pang is joined by the River Bourne and turns north to flow through the villages of Tidmarsh and Pangbourne , eventually entering the Thames between Whitchurch Lock and Whitchurch Bridge . The valley of the River Pang between Compton and Bradfield

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