Environmental lapse rate
1. Water flows at a depth of 10 feet in a rectangular canal 13 feet wide excavated in coarse
soil. The slope is 8 feet / 1000 feet. Determine the diameter of a concrete pipe flowing
full, that will have the same capacity when laid on the same slope.
2. A 42 inch diameter concrete outfall conduit 500 feet long discharges into an estuary. At
high tide, the sewer outlet is submerged a depth of 5 feet above invert. If the beginning
invert is at 301.6 ft and the outlet invert is 295.3 ft, determine the capacity and velocity of
the sewer outfall at high tide when flowing full. Assume n = 0.015
3. The volume of atmospheric water is 12900 km3. The evapotranspiration from land is
72000 km3/year and that from ocean is 505000 km3/year. Estimate the residence time of
water molecules in the atmosphere (in days).
4. A small water shed consists of 2 km2 of forest area (c = 0.1), 1.2 km2 of cultivated area
(c = 0.2) and 1 km2 under grass cover (c = 0.35). A water course falls by 20 m in length
of 2 km. The IDF relation for the area may be taken as i=80T0.2/(t+12)0.5. Estimate the
peak rate of runoff for a 25 yr frequency.
5. The annual rainfall at a place for a period of 10 years from 1961 to 1970 are respectively
30.3, 41.0, 33.5, 34.0, 33.3, 36.2, 33.6, 30.2, 35.5, 36.3. Determine the mean and median
values of annual rainfall for the place.
6. (a) Briefly explain how sea breeze is formed. When does it happen (day or night)? (b)
What is the wind direction in a mountain valley after sunset? What about right before
sunrise?
7. If the environmental lapse rate is larger than the adiabatic lapse rate, what is the stability
condition? Is the air quality generally good or poor under that condition? Briefly explain
why.
8. For a coning plume, what is the atmospheric stability class (stable, unstable, neutral)?
Does it come with high or low wind speed? Is it good for dispersing pollutants or not?
9. What is the concentration of 1-hour O3 standard at 25 oC and 1 atm in ug/m3?
10. When it comes to final disposal of solid and hazardous wastes, there are really only two
remaining viable options. What are they? Discuss the relative advantages and
disadvantages to the two major solid waste disposal options.
11. Explain why development and solid waste generation are closely linked.
12. Discuss the technological, regulatory, and societal factors that influence the cost of solid
waste disposal.
13. Compare the designs, waste types, and byproducts of landfills and incinerators.
14. Discuss the technological, regulatory, and societal factors that influence the cost of solid
waste and wastewater treatment and disposal.
15. There are several methods of solid-waste disposal including sanitary landfills,
incineration, chemical treatment, biological treatment, and discharge into sewers,
streams, and rivers. What are the advantages and disadvantages of each method? What
is the greatest source of municipal solid waste today?