Rivers and Discharge

Characteristics of Rivers and Discharge Comparison

• The mountains in Weaverville, California are barren on the eastern side due to a past fire and on the western side due to strip mining.
• Gold can be found in areas where water flows fast and holds onto the gold particles.
• Black sand, which contains high-density metals like iron and gold, is often found with gold.
• The presence of magnetite crystals in black sand is due to the alignment with the magnetic field of the rocks in the coast range.
• The amount of water flowing out of the Oroville Dam during the spillway incident was 110,000 cubic feet per second.
• Velocity and discharge are important factors in stream characteristics and erosion.
• Slope or gradient is a significant characteristic that influences velocity and discharge.
• The velocity of water is generally greater at the mouth of a river compared to the head due to channel characteristics and smoother flow.
• Discharge refers to the amount of water flowing through a river, and it determines the river's erosional power.
• The Mississippi River is one of the largest rivers in the United States, with a discharge of 110,000 cubic feet per second during a significant event.
• The Amazon River is the largest in the world in terms of both length and discharge.
• The Nile River, despite flowing near the equator, has a lower discharge due to passing through a desert, making it the 29th largest in terms of discharge.

River Erosion and Deposition

• Streams carry three types of loads: suspended load, dissolved load, and bed load.

• The bouncing of particles along the bottom of a river is called saltation.

• Competence refers to the maximum size of rock that a stream can carry, while capacity refers to the maximum amount of sediment it can carry.

• A river with a large capacity but low competence is a large river that is not moving very fast, like the Amazon.

• A river with a large competence but low capacity is a fast-moving, small river that can carry larger rocks.

• Deposition occurs when the velocity of a river decreases, causing sediment to drop out.

• Sediment dropped by a stream is called alluvium.

• Well-sorted deposits occur when a river is flowing fast and larger rocks settle out first, followed by smaller rocks and fine-grained sediment.

• The settling velocity of sediment determines whether it will be carried or deposited by a river.

• The longitudinal profile of a river shows its elevation changes from headwaters to mouth.

• A braided stream occurs when there is a flat slope and a large amount of sediment, causing the river to flow in multiple channels.

• Base level is the lowest point a stream can erode to, with ultimate base level being the ocean and temporary base level being a reservoir.Formation of Floodplains and River Flooding

• Floodplains are formed through downward and side erosion by rivers.

• A floodplain is a flat, fertile area that develops when rivers flood and deposit sediment.

• Natural levees form along rivers, creating boundaries for floodplains.

• Floodplains are important for agriculture and human settlements due to their fertile soil and proximity to water.

• Rivers typically exceed their banks onto the floodplain once every two years.

• Flood insurance rates are higher for areas prone to frequent flooding.

• A 10-year flood occurs when water reaches the natural levee approximately once every 10 years.

• A 50-year flood occurs when water covers the entire floodplain approximately once every 50 years.

• A 100-year flood occurs when water overflows the top of the floodplain.

• Flood insurance coverage is based on the average height the water will reach during a flood event.

• Meanders are formed when a stream valley is lifted up and cuts straight down, creating a meandering stream.

• Deposition features include deltas, which form at the mouth of a river where it meets a body of water.

Water Resources in California

• Death Valley and the Mojave Desert in California receive very little precipitation, making water availability a significant problem in the region.
• The complex system of aqueducts is used to transport water from areas with rainfall to areas with high demand.
• California faces two major problems with water: rain falls at the wrong time of year and in the wrong location.
• The Sierra Nevada mountains, covered in snow, serve as a water source for agriculture in California.
• Snowpack in the Sierra Nevada mountains helps recharge the groundwater in the Great Valley, which is crucial for agriculture.
• During a 10-year drought, California experienced high water prices and depleted aquifers.
• The Orville Dam incident filled up the aquifers to 70% in just one year, providing temporary relief.
• The hydrologic cycle involves reservoirs and pathways for water movement, including evaporation, precipitation, and transpiration from plants.
• Transpiration, the evaporation of water from plants, is significant for agriculture in California's Great Valley.
• Infiltration occurs when water seeps into the ground and reaches the water table, leading to the formation of lakes.
• Only about 3% of the planet's water is fresh water, with the majority locked up in glaciers.
• Surface water, such as lakes and rivers, accounts for around 10-12% of the total fresh water, while groundwater makes up about 20%.