Final answer:
The prevalence of road arteries in a watershed can affect water quality. The number of road miles in each watershed can be determined using the arteries feature class, and the three watersheds with the highest mileage can be identified by ranking the watersheds based on road mileage.
Step-by-step explanation:
The prevalence of road arteries in a watershed can affect the water quality. To determine the number of road miles in each watershed, you can use the arteries feature class. This feature class is a GIS dataset that contains information about the road network, including road length. By analyzing this dataset, you can calculate the total road mileage in each watershed.
To identify the three watersheds with the highest mileage, you would need to rank the watersheds based on road mileage. The top three watersheds with the highest mileage would be the ones with the most miles of road within them.
For example, let's say there are five watersheds: A, B, C, D, and E. After analyzing the arteries feature class, you find that watershed A has 10 miles of road, watershed B has 8 miles, watershed C has 15 miles, watershed D has 12 miles, and watershed E has 5 miles. In this case, the three watersheds with the highest mileage would be C, D, and A.