Week_6_Virtual River Discharge - Virtual River Discharge Slide 1 The goal of this exercise is to introduce you to some basic concepts about how rivers

Week_6_Virtual River Discharge - Virtual River Discharge...

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Virtual River DischargeSlide 1The goal of this exercise is to introduce you to some basic concepts about how rivers work.The term river describes water moving through a well-defined channel.This is a picture of Herd Creek in eastern Idaho with water flowing through its well-defined channel. The channel here is about 7 meters wide.Where do rivers get their water?Click the next button to go to the next pageSlide 2
Answer these questions:1. Discharge is an important concept. What statement best describes stream discharge?2. If the stream above were moving twice as fast, what would the discharge be?Slide 4Stream TerminologyBut, natural stream channels don't have a square meter cross-section shape and their velocity values vary a lot from spotto spot. As we shall see over the next few pages, a stream's cross-section can be complicated such that carrying out velocity measurements can be challenging. Before we consider how velocity values and channel shape are determined, let's examine a few terms used to describe streamsNotice that there is a right and left bank of the stream. The sides of a stream are named (right or left) relative to a view downstream. The arrow shows the directionof flow, which in the diagram on the right is away from us.In this diagram which side of the river is its left side?Side ASide BClick "Next" and we shall continue to find out about measuring stream velocity.Slide 5In order to measure discharge, we need to measure both the area of the cross section and the velocity of the water. (We'll measure the area later.) Remember that velocity has the units of speed which can be expressed as either feet per second, or meters per second.In a stream, velocity is measured by using a velocity sensor attached to a wading rod. Below (left) is a picture of a wading rod with the velocity sensor attached. The sensor has a set of cups (or a propeller device) that spins in moving water. Thefaster the cups spin, the greater the stream's velocity.Far left, John Stamm, a hydrologist, is holding a wading rod with a velocity sensor attached to the lower part of the rod. The sensor is connected by a wire to a digital display meter held by Professor Stamm.Left is a close-up of the velocity sensor (top) and its digital display meter (bottom).
Slide 6Below two students are measuring velocity near the right bank of a muddy stream. They mark their "position" in the stream by using a tape measure. Their position is the point where the wading rod touches the tape. The rotating cups are down in the water spinning like crazy.

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