The Hydrosphere. Introduction To Surface Water. What Do You Think?

Transcription

1 Introduction To Surface Water Unit Essential Questions: How does the Earth cycle its water through its major reservoirs? How does society s use of resources affect water quality? Presentation Objectives: Describe the distribution of water on Earth. Describe the movement of water through the water cycle. Explain the role of the sun in the water cycle. Identify and describe the four factors that influence the amount of runoff. Review the basic formation of a stream. Describe the methods used by streams to carry material. Define carrying capacity and describe the factors that influence it. Explain how a flood creates a floodplain and impacts society. Define river system, tributary, watershed, and divide. The Hydrosphere The hydrosphere includes all of the water both on and in the Earth. Oceans Freshwater Rivers and streams Lakes Groundwater Ice caps/glaciers Water Vapor Atmosphere Q1 Q2 What Do You Think? 0.003% of Earth s water is clean and available for our use. This means there is approximately 7 million liters of water per person. Why does more than one-third of the world s population NOT have access to clean, freshwater? Water is contaminated, overused, or economically difficult to access. Let s put this in perspective!

2 It s A Cycle! Q4 How Did You Do? The Earth s water supply is continuously recycled through the hydrologic cycle. The hydrologic cycle is a set of processes... Evaporation Precipitation Condensation Infiltration Transpiration Groundwater Flow Where does the energy come from? The Sun!! Clouds Precipitation Stream/River Infiltration Groundwater Groundwater Flow Condensation Atmosphere Evaporation Ocean Becoming Surface Water The source of freshwater is the oceans. When water evaporates, the salt is left in the ocean. When it precipitates on land, it falls as freshwater in the form of liquid water or snow. Often this precipitation becomes runoff. Water flowing downslope along Earth s surface. Q4 How Much Is There? The amount of runoff increases when the amount of infiltration decreases. Vegetation decreases runoff! Allows the rain to infiltrate because it reduces the rate at which the rain reaches the ground. Plants prevent soil compaction, which allows more infiltration. Q5

3 It s Raining Cats and Dogs! Q6 Another factor that influences the amount of runoff is the precipitation rate. There is not enough time to infiltrate in to the ground, so it stays on the surface. Another factor that influences the amount of runoff is the soil composition. Porosity is the measure of how much of a soil is pore spaces. A high porosity soil decreases runoff because it allows more water to infiltrate. Q8 The last factor that influences the amount of runoff is the topography. Q9 What is a stream? Precipitation and runoff can form channels. Deepen, widen, and get longer with subsequent rains. The smallest channels are known as rills. Water moves faster on steep slopes, so steep slopes increase runoff. Water moves too fast to infiltrate! Q7 Soil has pore spaces, which are the spaces between the grains where water can go. Heavy Rain increases runoff! Going Down? Is It A Hole-y Soil? When they widen and deepen they become gullies. Rill Gully Stream

4 Loaded with stuff! As streams make their way toward their final destination, they carry both organic and inorganic materials. Organic Microorganisms Plants Animals Inorganic Sediments Dissolved solids Dissolved gases Q10 How Does It Move? The method will depend on particle size. The size carried in suspension will depend on the water velocity. Q11 Carrying Capacity Q12 The amount of material a stream can transport is known as the carrying capacity. Carrying Capacity is dependent on Velocity which is dependent on the slope, depth and width of the channel. Discharge which is the volume of water that flows over a particular location within a given period of time. As discharge increases, carrying capacity increases. What Happened? Discharge = width x depth x velocity

5 Amount of water varies with the weather conditions. A flood occurs when there is more water in a stream than it can hold. Too Much Water! Q13 Do Floods Occur In Connecticut? The excess water spills over the sides onto the flat land next to the stream called the floodplain. When the river floods, the water s velocity decreases, which means it has less energy and its sediment is deposited on the floodplain. Soil is good for farming because it is VERY fertile! In 1955, Connecticut experienced a flood that is considered the worst natural disaster in the state s history. Hurricanes Connie and Diane hit five days apart.