Name: __________________________ S.S. No. ____________________ Grade: _______

Instructions: Open book, closed notes. Use engineering paper. When you are finished, staple your work in sequence, and return this sheet with your work.

1. (30%) Given the following measured recession flows in a certain river:

   Time (hr)    0          1       2       3          4       5       6
   Q (m3/s)    1000    920    846    779    716    659    606
   

   Calculate:

   1. The time of storage t_s;
      
   2. The recession constant K;
      
   3. The volume released from storage between 3 hr and 6 hr;
      
   4. The total volume released from storage assuming that the flow eventually recedes back to zero.
      

2. (30%) A reservoir is to be built with a storage capacity of 50 hm³. The contributing drainage basin is 800 km², and the mean annual runoff at the site is 200 mm. Assume well graded sediment deposits with average specific weight 1400 kg/m³. (a) How long will it take for the reservoir to lose 20% of its storage volume? (b) How long will it take for the reservoir to fill up with sediment? Estimate sediment yield by the Dendy and Bolton formula.

3. (40%) Please answer the following questions briefly:
   
   1. What are the differences between surface water and groundwater? Explain.
      
   2. What is the difference between the Modified Clark method used in HEC-HMS and the Clark method as explained in the textbook?
      
   3. What feature of the Rainflo model distinguishes it from HEC-1?
   4. What is the difference between lumped and distributed catchment models? Is the ModClark lumped or distributed?
   5. Explain why GIS has difficulties in modeling catchment runoff.
   6. Why is the USGS State Equations likely to have poor accuracy?
      
   7. Why is sediment production different that sediment yield?
      
   8. Describe the various types of solids likely to be present in streamflow.