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          12       24       36          48
   Q (m3/s)    1000    882      779    687       606
   

   Calculate:

   1. The time of storage t_s;
      
   2. The volume released from storage between in the first 24 hr;
      
   3. The volume released from storage between in the second 24 hr;
      
   4. The total volume released from storage assuming that the flow eventually recedes back to zero.
      

2. (30%) Use the Clark method to derive a 1-h unit hydrograph for a catchment with the following time-area diagram:

   Time (hr)        0       1       2        3        4         5        6
   Area (km²)        12     20      42       66       30      16

   Use K= 2 hr, and Delta t= 1 hr.

3. (60%) Please answer the following questions briefly:
   
   1. What are the differences between surface water and groundwater? Explain.
      
   2. How do the vegetated earthmounds in the savanas of Central Brazil relate ecology with surface water and groundwater?
   3. What is the contribution of Rorabaugh in hydrology?
   4. What is the difference between lumped and distributed catchment models? Is the ModClark lumped or distributed?
   5. How did the Alamar flood hydrology study evaluate the effect of lining the 10-km channel with concrete?
   6. Why is sediment production different that sediment yield?
      
   7. Why is the Colby method a good method for discharge of sands?
   8. What is the cause of global warming? To what can it be attributed?