Question

Hydrology ENV 321 Homework #1 Due: Friday, September 6 at 1:00pm 1. Convert (show all conversion steps for full credit; convert only one unit for cach step as demonstrated in class): a) acre-feet/day to mgd (mgd is million gallons per day] b) cfs to cms c) inches/hr rainfall to mm/day rainfall d) short tons/acre-day to Mg/hectare-year [Mg is megagrams e) inches"F to cm/ C [be careful, this one may trick you] 2. Define the hydrologic cycle component and indicate how they are different from each other for each case below a) Infiltration and Percolation. b) Baseflow and Interflow. c) Evaporation, Transpiration, and Evapotranspiration. 3. For a 1.45-inch rainfall event over a standard city block (660 x 660 feet-square), estimate the volume of water entering the storm sewer in units of acre-feet and cubic-feet if 65 % of the precipitation is captured by the sewer. [Answer: 34,212 ft, you determine the answer in acre-feet] 4. A green roof is designed to hold up to 0.8 inches of precipitation before water starts to runoff. For a building with a green roof that is 1,000 x 750 feet, determine the weight of water (in Ibs) that would be on the roof when the green roof is saturated. Liquid water is 62.4 pounds/cu-foot (Ibs/ft'). Answer: 3,120,000 pounds] 5. Estimate the weight load to a roof in Ibs/ft for 45 inches of snow. Assume that 10 inches of snow is equivalent to 1 inch of liquid water if melted. Liquid water is 62.4 pounds/cu-foot (Ibs/ft). [Answer: 23.4 psf) 6. If the weight limit for a roof is 55.0 lbs/ft, how much snow can be on the roof before it must be removed? Again assume that 10 inches of snow is equivalent to I inch of liquid water if melted. Liquid water is 62.4 pounds/cu-foot (Ibs/ft'). [Answer: -106 inches] 7. Water is flowing into a vertical-wall box stormwater catch basin at 0.035 m2/s. The catch basin dimensions are 3x4x2 meters (Ixwxh) before it overflows into the storm sewer. How long can the water flow into the catch basin (in minutes) before it starts to feed the sewer? (Answer: 11.4 minutes 8. Determine the dimensions for a 12-feet deep vertical-wall reservoir with a design flow rate of 16 cfs entering the reservoir. The reservoir should be designed to hold stormwater for 30 minutes before overflowing into a stormwater channel. The l:w dimensions are to be 2:1. (Answer: 69.28 ft (I) x 34.64 ft (w) x 12.00 ft (h))

Answer 1

aexe feetag to Tacre feething to myl. - million gallons for day = 0.32585 cubic feet / second to cubic meter per second liftels to m3/s. = 0.0282/68 4 6 592 0 inches/hour ainfall to mm/day rainfall I inch/ hour ainfall to mm/day rainfall - 2.5 1 inch = 25 4* num. (1) short tons acre-day to my hectare year.. I short fons per arre day to ing per hectare your 0.00643 7 57753 ( inches/ of to cm/oc. tinches / degree fahrenheit - 1.8 cml degree celsius.

1.

The 2. The recycling of water through continuous movements in air on earth's surface and under the ground Catmosphere in whole) is known as hydrological cycle or water cycle. The important components (preuss) involved in hydrological cycle arel vaporisation, precipitations, infiltration, percolation, Surface run off, condensation, evaporation, and transpiration or evapotranspiration. Infiltration and Percolation..

2

v piguar (a) It Infiltration and Percolation. Infiltration is the brouss of entering of water into the Soil through ground Surface. It goes vestically and happens at uppermost straturn of soil. It is measured in mm/hr on in/hr , it is fast in beginning Stage - and slow at later stage.. whereas Pescolation is the breess of passing of ligeid through a filter. It happens at far de foth under the ground and accompanied with vertical movement, joining of water table. It is slower in speed as compared to infiltration.

2 a

6 Base flow is subsurface flow occuring at shallow depth above ground water table. It is delayed fordeess of lateral flow. C Constant) Whereas Interflow is actual lateral movement of water which occurs during precipitation and happens through upper soil surface. It happens in unsatured or vadose zone. O traforation is surface level procedure which oneers'

2b

oll surface. vadose zone. It happens on unsatured on whereas and! o traposation is surface level Procedure which wers in warm or cold condition and may happen from living or non living surface. Troms pisation is physiological process which ours in foresence of sunlight and happens only from living bodies. It has remarkable importance in blant wofe. Evaketoonisfization is a preuss through which is 6 Comboration of evaporation and fronspirate on It is responsible for I 715% of atmosphere water vakor. In real, evapotronspiration is combined form of - erakoration of water from soll/earth's surface and tonskisation of moisture from Plants surface which results in freispitation.

2c

I precipitation ↑ Evapotsons pirates on 7 Surface runoff Initial losses Impornas Penas Root zone Interflow Infiltation onsomitionron Percolation saturated zone Ground fwater flow- Recharge

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