a. You are asked to assess the impact of development near Lake Tahoe, California. First, draw the watershed boundaries that define the watershed draining to the X in Homewood Canyon, which then discharges in to the lake.  

b- To gain a basic understanding of the watershed’s function, you examine data collected during one rain storm. Three rain gauges around the watershed record rainfall amounts of 40 mm, 45 mm and 56 mm. Calculate an Effective Uniform Depth (EUD) of precipitation (P) for the watershed. (To aid in selecting a method for calculating EUD, you may assume the gauges are evenly spaced and the terrain not too steep.)

c- Estimate the runoff Q from the watershed using the SCS Curve Number Method. The equation is given to the right. For now, assume the watershed is completely forested with a runoff curve number of 50.

d- A logging company with permits in this national forest wants to clear-cut the watershed. How would this change the runoff if it increases the curve number to 75?

e- Would you expect baseflow to the creek to go up or down after clear-cutting? Why?

f- How much runoff would be produced by covering 20% of the forested watershed in development with impervious surfaces (CN=98) instead of clear-cutting?

g- In this alternative development case, would you expect baseflow to the creek (on average over the watershed) to go up or down? Why?
 

Transcribed Image Text:

Madden SKI HOMEWOOD 10 Canyon Lake Loulse Homewood ENIS Peak 47Quail Lake E Ridge R S Mirtes Knee T Madden SKI HOMEWOOD 10 Canyon Lake Loulse Homewood ENIS Peak 47Quail Lake E Ridge R S Mirtes Knee T

Answer rating: 100% (QA)

A Watershed Watershed is an area of land which drains water to a specific point The area is composed ... View the full answer