Geography 12 PPT Worksheet: Rivers A ________________ is the land area from which a river or stream gets its ___________ supply. _____________ or ___________ are the highland areas which ______________ one basin from another. A ______________ river pattern is like the veins of a __________. This pattern is found in ___________areas with a ___________ bedrock or surface. A _____________ river pattern is found where there are differences in the ______________ or in _____________________ regions. There may be inclined layers of _____________ resistances that help form this pattern. A ___________________ pattern develops where there are long ______________ ridges in mountains or hills. A ________________ river pattern develops around a volcano or circular mountain or ____________ hill. A _________________ river pattern develops over __________ which has strong _______________ or joints in a rectangular pattern. A _____________ river pattern develops where continental ___________ have __________ the land’s surface, rearranging the flows of streams and rivers. Rivers which flow year round are called ____________ rivers. Rivers flowing only during a wet season are called _____________ rivers. Rivers that __________ flow, every now and then, are called ________________________ rivers. Rivers in ____________ are commonly ephemeral or intermittent. A river or stream’s velocity is affected by _____________, ____________, ___________________ and __________________. Geography 12 PPT Worksheet: Rivers A stream’s _______________ refers to the ____________ of water flowing ______________(m3/s) that it carries. A stream’s velocity is __________________ to its discharge. The profile, _______________ or degree of ___________ of a stream affects its velocity with _______________ favouring _____________ velocities. Streams in _____________ have ____________ profiles while streams in ______________ have more __________ profiles. A stream typically flows ____________ near its mouth where it joins a lake or ocean. Since rivers generally flow faster ______________ than upstream, _______________ is not the only factor affecting stream velocity. The ______________ the channel of a stream, the ______________ its velocity which is _______________ by rough features slowing the flow. ____________ in a river channel and __________ along the bottom and sides of a channel _________ a river’s velocity. A mud bottom has less _____________ than a rocky bottom which helps to ________________ a river. A stream’s ________________ is the ratio of its cross-sectional area to its wetted perimeter. A ___________ hydraulic radius generally means ___________ friction which produces a ___________ flow and therefore _____________ velocity. The hydraulic radius is a measure of how ___________ a river flows. For two rivers with the ___________ cross-sectional area, a _______________ river has a _____________hydraulic radius which produces a _____________ velocity. This is because the river water has more contact with its channel which produces _______________, slowing the river down. Geography 12 PPT Worksheet: Rivers For a river with an even channel, the water ______________ in the ______________, near the ___________. In deeper places the flow is _____________ while in shallower places the flow is ___________ because there is ____________ surface contact and ____________ in shallower places. ____________ of a stream’s bed and sides happens when the stream’s velocity is higher. _________________ (very fine sand) erodes away first. In low velocity streams, clay and silt are transported the easiest ________________ being carried in a river or stream is ______________ unless the velocity is very high. The ___________ a river’s velocity, the _____________________ particles it can carry. As a river slows down, it is likely to _______________ materials. Water has four main erosion processes: _____________, _____________, _______________ and ______________________. The ____________ of a river’s bed and sides by suspended particles in the moving water is called _____________. The ________________ of rock and gravel fragments against each other is called ___________________. The _________________ of soluble minerals and transporting them to an ocean is called __________________. The reason _______________ are ______________ is that rivers continually carry _________________ from their beds and sides to the oceans. The ___________ of moving water against the bottom and sides of a river channel which slowly erodes it away is referred to as water’s ___________________. Water’s hydraulic action is more pronounced in _____________ and ____________. Geography 12 PPT Worksheet: Rivers ____________________ refers to the amount of __________-sized particle that a river can erode and carry away. The _________________________ of materials a stream or river carries depends on its _______________ and the _______ of sediments of the river. A river’s _____________ is the maximum amount of _____________ materials that it can carry suspended in its waters. As the ______________ of a river increases (volume per time), the capacity or sediment load increases _______________ by a factor of two or three. For instance, if a stream’s discharge is ___________ in a flood, its capacity may increase by _____________ times. Streams carry particles by ______________, _____________, ______________ and ________________. When streams ______________ along this is called ______________. When ______________ are _____________ along the bottom of a stream bed, this is called ______________. ________________ is the process by which water ______________ keeps particles afloat. ______________ is the process by which _______________ substances are carried by a river. _____________ is the term used to describe river-deposited sediment. Alluvium is usually deposited in _____________. _______________ are usually __________ because heavier particles settle out __________, with the lightest (finest) particles settling out ________. End of First Class on Rivers Geography 12 PPT Worksheet: Rivers As a river flows, especially with a more ____________ gradient (slope), it _____________ (wanders sideways), creating broad curving __________. River banks are ________ at the __________ edges, and ____________ occurs on the _________ curves creating features called ____________. This happens because the _________ and deepest water is found on the __________ banks while the _________ and ____________ water is found on the _________ banks of a meander curve. As erosion continues, meanders may ____________ causing incipient ____________ which later may become _______________ as _____________ separate the meander from the main course of the river. Seasonal river floods _________ areas on either side of the river to create a ____________. As fast-moving flood waters, _________ with sediments, spill over onto surrounding ___________ flood plains, they ______________ and ___________ their sediments onto the _______ of the river and the flood plain. The raised edges of a river bank are called ___________ and they are formed by flood waters __________ their sediments on the ___________ as they _________ in the shallower bank region. Moving away from a river with its levees, a person will find lower regions which are referred to as ________________ areas. A ________________ or stream maintains a __________, neither ___________ its bed nor ___________ further sediments. A ___________ stream carries an especially large load of ________ and rock ____________ called its ___________. If a braided stream is ____________, it ___________ much of its sediment and _________ into many ______________________. Braided streams are common in ______________ deserts (flatter) during _____________ and in Geography 12 PPT Worksheet: Rivers streams flowing from ______________. In both of these cases, a sudden flood of water picks up a large amount of ____________ and ______________ these as they __________ down. ___________ are flat areas of __________ deposits found at river ____________. The cross-connecting channels in deltas are called _______________. Deltas are ____________ as sediments are deposited and are _________________ by the forces of ocean or lake waves. Deltas may be ___________ or fan-shaped like the Nile delta or elongated along the river channel like the Mississippi. _______________ delta or ____________ or tooth-shaped like the Tiber River delta. In ______________ marshy areas where ___________ water rivers meander and oceanic _________ periodically flow upriver, there is a _____________ of waters and sediment deposit, forming an estuary delta. The Cowichan river forms an ___________ delta where it flows into Cowichan Bay. ______________ are regions where river waters are ___________ and ___________before entering the ocean. They are regions _________ in wildlife and in the Cowichan estuary, plentiful in __________ for ___________ during both their ________ stage and last parts of their life cycle. The complexity of the tributaries that feed into a river can be measured with an _____________ system. A ________ order stream has two tributaries of order 1 flowing into it. After two ________ order tributaries feed into a stream, it is called a _________ order stream etc. _______________ are deposits of sediment formed by fast-flowing streams carrying large amounts of ____________ which abruptly flow onto level plains, _____________ the flow and causing the sediments to ________________ in the form of fans. Alluvial fans are common Geography 12 PPT Worksheet: Rivers in __________ or ___________ environments. Where several alluvial fans grow together, structures called _____________ form. In an enclosed basin with sloping ____________, the central flat plain may intermittently fill up with water as a shallow _________ and then dry through evaporation leaving __________ behind. The central flat region is called a __________ and may have layers of _______________, sometimes referred to as salt or alkali ________. In deserts the dry remains of an ephemeral or intermittent stream is called an ___________. When water erodes a desert, creating a ravine or canyon, this is referred to as a _________. In more humid climates, a wadi is referred to as a _________ or ____________. _________ are flat-topped hills with steep sides or _______________. Mesas develop in lands where a __________ layer of sedimentary rock or igneous sill ____________ __________ sedimentary layers. A ___________ is a small mesa while a ___________ is just a pointed remain of a butte. _____________ are regions of soft rock which have been _____________ by intermittent water into _________, gullies and sharp-edged ______________. ____________ rivers tend to be ___________, narrow with _______ moving waters due to the ______________ or gradients they have. Youthful rivers have much erosion on their _________________ with many ___________ and rocks that deflect their waters, causing them to take __________ paths. ___________ rivers begin to ___________ because they have more erosion at their __________ than their __________. They tend to form narrow ___________ and __________ that they flow through. Mature rivers have fewer _________ and ___________. Mature Geography 12 PPT Worksheet: Rivers rivers have a _________ profile (gradient) and a ____________ crosssection. In old age rivers, most of their erosion takes place along their __________. They form large ______________, large curving ____________ and __________ lakes. Old river have raised river banks called _________ and away from these are lower-lying parts called ____________. Old age rivers tend to be ________ and ____________. When tectonic movements of the earth’s crust _________ a region causing a steeper _____________ (profile), old age rivers may be _______________, making the river once more into a “young” river. With a ___________ gradient, the river now has more ___________ erosion, carrying away sediments and leaving just ________ and ___________ and again taking on a ___________ as it cuts downward through its bedrock. A river _________ tends to have major __________ erosion, deepening its channel. Then a river tends to have more erosion at its __________, causing its _____________ to __________. Later if the land is _____________, the river may again have more ________ erosion followed once again with subsequent ________ erosion. This pattern produces flat __________ that mark where former _________ ___________ were.