Chapter 8.4A, Problem 7A

Calculate the gradient, or slope, of this portion of the Missouri River by following the steps below:

Step 1: Locate a contour line that crosses the river. Note: An index contour crosses the river in Section 26 (lower left portion of the map). Follow the index contout to the right to establish its elevation.

Elevation: ___________ feet

Step 2: Locate a second index contour that crosses the river. Note: in Section 11, between the letters V and E in the word RIVER. What isits elevation?

Elevation: ____________ feet

Step 3: Use a string and the bar scale to measure the approximate distance (to the nearest mile) between these two index contours.

Distance: ______________ miles

Step 4: Calculate the gradient of the river by using the following formula:

$\text{Gradient}=\frac{\text{Difference in elevation }\left(\text{feet}\right)}{\text{Distance}\left(\text{mi}\le \text{s}\right)}$

Gradient ___________ feet per mile