Science- Chapter 9 Surface Water

Explanation
Water flowing downslope along the Earth's surface is called runoff. Runoff occurs when precipitation, such as rain or snowmelt, exceeds the infiltration capacity of the soil, resulting in the water flowing over the land surface. This water then collects in streams, rivers, lakes, or other bodies of water. Runoff plays a crucial role in the water cycle and is an important source of freshwater for various ecosystems and human activities.

Explanation
The factors that affect runoff include slope, soil composition, rate of precipitation, and vegetation. Slope plays a significant role in determining the speed and amount of runoff as steeper slopes tend to generate more runoff. Soil composition affects the infiltration rate, with compacted or impermeable soils resulting in more runoff. The rate of precipitation also influences runoff, as intense rainfall can exceed the infiltration capacity of the soil, leading to increased runoff. Vegetation, such as forests or grasslands, can help reduce runoff by intercepting rainfall and promoting infiltration.

Explanation
A watershed refers to all the land area that contributes water to a specific stream system. It includes all the surface water and groundwater that flows into the stream. The concept of a watershed helps in understanding how water moves and interacts with the landscape. It is an essential unit for managing water resources and studying the impact of human activities on the environment.

Explanation
A high land area that separates one watershed from another is called a divide. This term refers to the elevated terrain that acts as a boundary between different drainage basins, directing the flow of water into separate areas. A divide can be a mountain range, ridge, or even a small hill that determines the direction in which water will flow. It plays a crucial role in determining the boundaries of different watersheds and the overall hydrological system of a region.

Explanation
When material becomes dissolved in a stream's water, it forms a solution. A solution is a homogeneous mixture where the solute (material) is evenly distributed and dissolved in the solvent (water). Therefore, the correct answer is "solution" as it accurately describes the state of the material after it dissolves in the water of a stream.

Explanation
Particles that are small enough to be suspended in the moving water of a stream are carried in suspension. This suspension consists of various sediment types such as silt, clays, and sands. When the water's turbulence is strong enough to support these particles, they remain suspended and are transported by the stream's flow.

Explanation
The term "bed load" refers to the sediment or particles that are transported along the bed of a stream by the force of the water. This includes sand, pebbles, and cobbles that can be rolled or pushed by the stream's water.

Explanation
The measure of the volume of the steam water that flows over a particular location of a given period of time is referred to as the discharge. This term is commonly used in hydrology and refers to the quantity of water that passes through a specific point in a river or stream. It is typically measured in cubic feet per second (cfs) or cubic meters per second (cms) and is an important parameter for understanding the flow rate and dynamics of water in a particular system.

Explanation
To calculate discharge, you need to consider three factors: width, depth, and velocity. Width refers to the width of the channel or area through which the water is flowing. Depth is the measurement of how deep the water is at a specific point. Velocity is the speed at which the water is flowing. By combining these three factors, you can calculate the discharge, which is the volume of water passing through a given point in a specified amount of time.

Explanation
The Mississippi River is the correct answer because it is the longest river in North America, stretching approximately 2,320 miles. It flows through 10 states and serves as a major transportation route and water source for millions of people. It is also known for its rich biodiversity and plays a significant role in the region's economy and history.

Explanation
The Amazon River is considered the largest river in the world based on its volume of water flow. It has the largest drainage basin, covering a vast area of South America. The river stretches over 6,400 kilometers and carries more water than any other river, accounting for approximately 20% of the world's total river flow. Its size and the number of tributaries it has contribute to its status as the largest river in the world.

Explanation
A flood is a natural disaster that happens when water overflows from a stream or river and spreads onto the neighboring land. This can occur due to heavy rainfall, melting snow, or dam failure. The excess water cannot be contained within the stream's banks, causing it to spill over and flood the surrounding areas. Floods can cause significant damage to properties, infrastructure, and can also pose a threat to human lives and wildlife.

Explanation
A floodplain is a broad, flat area that is adjacent to a stream's bank and is prone to flooding during times of excess water. It is a low-lying area that is often covered by water during flood events. The floodplain acts as a natural flood storage area, allowing the excess water to spread out and dissipate, reducing the risk of flooding in other areas. It also provides important habitat for various plants and animals that are adapted to periodic flooding.

Explanation
Capacity refers to the ability of a stream to transport material. It is a measure of the maximum amount of sediment that a stream can carry. A stream with high capacity has the ability to transport a large volume of sediment, while a stream with low capacity can only transport a small amount of sediment. Capacity is influenced by factors such as stream gradient, velocity, and discharge. A stream with a steep gradient, high velocity, and high discharge will have a greater capacity to transport material compared to a stream with a gentle gradient, low velocity, and low discharge.

Explanation
The answer "capacity" is correct because the amount of water that a stream can hold or carry is determined by its capacity. This capacity is influenced by the velocity of the water and the volume of water flowing in the stream. A stream with a higher velocity and a larger volume of water will have a greater capacity to hold and transport water compared to a stream with lower velocity and less water.

Explanation
The correct answer is load because load refers to all the materials that are carried by the water in a stream. This includes sediments, rocks, debris, and other particles that are transported by the flowing water. The load of a stream can vary depending on factors such as the velocity of the water, the size of the particles, and the overall stream dynamics.

Explanation
A stream that flows into another stream is referred to as a tributary.

Explanation
The term "river system" refers to the entire network of rivers, streams, and tributaries that are interconnected and flow into a larger main river. In this context, the question is asking for the collective term that encompasses all the tributaries and the stream. Therefore, the correct answer is "river system."

Explanation
The amount of dissolved material in water is commonly measured and expressed in parts per million (ppm). This unit of measurement indicates the concentration of a substance in water by expressing the number of parts of the substance per one million parts of water. It is a useful measure to understand the level of pollutants, minerals, or other substances present in water, especially in environmental and industrial contexts. Ppm provides a standardized and easily comparable way to quantify the concentration of dissolved material in water samples.