Rivers

• Waterfalls are found at the youthful stage of the river where vertical erosion takes place.
• Waterfalls are formed where there is an area of hard rock overlaying a layer of soft rock.
• The force of hydraulic action from the falling water results in erosion of both the plunge pool and the notch.
• Over time, the waterfall gradually retreats upstream as the plunge pool and notch are eroded more and more.
• The processes of erosion, deposition, and transportation shape a river.
• People interact with and manage surface processes in rivers.
• Rivers have an impact on the location and origin of settlement in Ireland.
• The journey of a river from its source to the sea is called its course.
• The course of a river is broken up into three stages: upper course, middle course, and lower course.
• River erosion involves the transportation of pebbles and stones by the force of water.
• River transportation occurs through traction, saltation, solution, and suspension.
• River deposition occurs when a river slows down and loses energy, typically at the inside bend of a meander.
• Landforms of a youthful river include v-shaped valleys, interlocking spurs, and waterfalls.
• V-shaped valleys are formed through erosion in a river's youthful stage.
• Interlocking spurs are areas of high ground that appear to lock together on either side of the river.
• Waterfalls are formed by the force of falling water creating a plunge pool at the base, which wears away the base by abrasion.
• The rock above the plunge pool is undercut and eventually collapses into the plunge pool, causing the waterfall to erode its way upstream.

  <Title>: Landforms of a Mature River
• In the mature stage of a river, erosion occurs laterally (sideways) rather than vertically (downwards), creating a wide river valley with less steep sides.
• Flood plains are flat areas of land on either side of the river channel, covered in fertile soil known as alluvium.
• Meanders are formed by a combination of erosion and deposition in the mature and old age stages of a river.
• Water flows more quickly on the outside bend of a meander, eroding the bend, while water flows more slowly on the inside bend, depositing material.

  <Title>: Landforms of an Old River
• Levees are build-ups of alluvium on the banks of a river, formed by deposition during floods.
• Ox-bow lakes are horseshoe-shaped lakes formed by river erosion and deposition on the flood plains of old rivers.
• Ox-bow lakes are formed when erosion takes place on the outside bank of a meander, and during times of flood, the water breaks through the neck of land and flows in a new, more direct course.
• Ox-Bow Lakes – Formation: Deposits of alluvium build up and seal off both ends of the meander, forming an ox-bow lake. Over time, the lake may dry up.
• Delta – Formation: When a river reaches a lake or the sea, it slows down and drops sediment at the mouth of the river, forming a delta. Large deposits build up over time and block the river's entry to the sea, leading to the formation of distributaries.

  <Title>: Rivers and Human Interaction
• Case Study: Flooding in Mallow: The town of Mallow in Co. Cork has a history of flooding. A flood relief scheme was implemented to prevent serious damage to homes and businesses from flooding.
• Achievements of the flood relief scheme: Provided protection against a one-in-one-hundred-years flood event, developed a flood warning system, reduced damage to homes and businesses, reduced stress and anxiety, reduced financial loss to local businesses, reduced disruption to the local community. Built flood defences including walls, storm drains, and pumping stations, designed with future climate change in mind.