1-1. Using Eq. 1-1: AS = 620 - (320 + 100 + 150) = 50 mm. 
         The change in volume of water remaining in storage is:

         AS = 50 mm X 2500 km2 X 103 hm3/km3 X 10-6 km/mm = 125 hm3. ANSWER.



      1-2. Using Eq. 1-1: AS = 27 - (10 + 7 + 9) = 1 in.
         The change in volume of water remaining in storage is:

         AS = 1 in. X 85 mi2 X 640 ac/mi2 X 0.08333 ft/in. = 4533 ac -ft. ANSWER.
.


      1-3. Using Eq. 1-2: AS = 850 - (420 + I + 225) = 0.
         The volume of infiltration is: I = 205 mm. Expressed in cubic 
         hectometers:

         I = 205 mm X 350 km2 X 103 hm3/km3 X 106 km/mm = 71.75 hm3. ANSWER.



      1-4. Using Eq. 1-3: Q = 35 - 28 = 7 in. The mean annual runoff is:

           7 in./y X 60 mi2 X (5280 ft/mi)2
          -               = 30.94 ft3/s. ANSWER.
           12 in./ft X 365 d/y X 86,400 s/d
























                       3