QUESTIONS

  1. What is the hydrologic cycle?

  2. Name the liquid-transport phases of the hydrologic cycle.

  3. Name the vapor-transport phases of the hydrologic cycle.

  4. What is a catchment?

  5. Give two examples of engineering problems (different from those mentioned in the text) where hydrologic knowledge is necessary to obtain a solution.

  6. What is material model? A formal model?

  7. What is an iconic model? An analog model?

  8. What is a deterministic model ? A lumped model?

  9. Contrast conceptual and parametric models.

  10. Contrast analytical and numerical solutions.

  11. What is a small catchment from the flood hydrology standpoint? A midsize catchment? A large catchment?

PROBLEMS

  1. During a given year, the following hydrologic data were collected for a 2500-km2 basin: total precipitation, 620 mm; total combined loss due to evaporation and evapotranspiration, 320 mm; estimated groundwater outflow (including groundwater depletion), 100 mm ; and mean surface runoff, 150 mm. What is the change in volume of water remaining in storage in the basin during the elapsed year? (Volume in hm3, i.e., millions of cubic meters).

    Using Eq. 1-1:  ΔS = 620 - (320 + 100 + 150) = 50 mm.

    The change in volume of water remaining in storage is:

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

  2. During 2012, the following hydrologic data were collected for a 85-mi2 watershed: total precipitation, 27 in.; total combined loss due to evaporation and evapotranspiration, 10 in.; estimated groundwater outflow (including groundwater depletion), 7 in.; and mean surface runoff, 9 in. What is the change in volume of water remaining in storage in the watershed during 2012? (Volume in ac-ft).

    Using Eq. 1-1:  ΔS = 27 - (10 + 7 + 9) = 1 in.

    The change in volume of water remaining in storage is:

    ΔS = 1 in. × 85 mi2 × 640 ac/mi2 × 0.08333 ft/in. = 4533 ac -ft.  ANSWER.

  3. During a given year, the following hydrologic data were collected for a certain 350-km2 catchment: total precipitation, 850 mm; combined evaporation and evapotranspiration, 420 mm; and surface runoff, 225 mm. Calculate the volume of infiltration (in hm3, i.e., millions of cubic meters), neglecting changes in surface water storage and groundwater effects.

    Using Eq. 1-2:   ΔS = 850 - (420 + I + 225) = 0.

    The volume of infiltration is: I = 205 mm. Expressed in cubic hectometers:

    I = 205 mm × 350 km2 × 103 hm3/km3 × 10-6 km/mm = 71.75 hm3.   ANSWER.

  4. During a given year, the following hydrologic data were measured for a certain 60-mi2 watershed: total precipitation, 35 in.; and estimated losses due to evaporation, evapotranspiration, and infiltration, 28 in. Calculate the mean annual runoff (in ft3/s). Neglect changes in surface water storage and groundwater effects.

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

               7 in./y × 60 mi2 × (5280 ft/mi)2
    Q = __________________________________ = 30.94 ft3/s.   ANSWER.

              12 in./ft × 365 d/y × 86,400 s/d

http://openchannelhydraulics.sdsu.edu
150709 17:30

Documents in Portable Document Format (PDF) require Adobe Acrobat Reader 5.0 or higher to view; download Adobe Acrobat Reader.