Homework Assignment 11

After running the respective tutorial, read the following set of questions and write half a page paragraph about what you have learned from this lesson. At this point, you should be able to answer these questions or at least have them help you in writing your paragraph.

Post this paragraph, along with a screen capture, or two, developed from the results of the tutorial, to your CE531 homework page, then email the TA (include the URL to your homework page).

Always try to make your assignment page look as nice and professional as possible.

Hydrological Parameters from Digital Data

What are the two main classes of input parameters most hydrologic models require?

How does the application of the GIS concept of “map overlay” help in computing composite hydrologic parameters?

What are the required GIS data for the computation of each of the following: composite curve numbers, runoff coefficients, Greean & Ampt parameters and Rainfall?

How would you classify the following 3 soils: Soil 1 with infiltration rate 0.25 in/hr, Soil 2 with infiltration rate 0.05 in/hr and Soil 3 with infiltration rate 1.5 cm/hr?

Which watershed produces more runoff, a watershed A with CN 94, watershed B with CN 63? Why?

Extra Questions:

Here are some extra questions for you to think about.

To be able to overlay a soil map to compute hydrological parameters, what is the key attribute needed to be in the attribute table of the map? What is it for the land use map?

In WMS, in order to compute composite curve numbers, we will need to read in a table relating land use and soil type to curve numbers. Why do we need to do that?

What map overlay method is usually used when computing hydrologic attributes in WMS?

What are the two methods that WMS offers to compute time of travel?

What is the relationship that WMS uses between lag time and time of concentration?