Page 41 - Water Engineering Hydraulics, Distribution and Treatment

19
References
How many days of draft can a raw water reservoir support
1.4
for a city of 400,000 people? The reservoir has a water surface of
tial area, assuming (a) an average water demand of 150 gpcd =
2
2
568 Lpcd; (b) population = 30,000; (c) fire flow requirement =
5.8 mile = 15.02 km and an average effective depth of 18 ft =
500 gpm = 2,082 L∕min = 32 L∕s; and (d) recommended water
5.49 m.
velocity = 3.5ft∕s = 1.07 m∕s.
What percentage of mean annual runoff is to be consumed
1.5
Roughly, what is the replacement cost of the waterworks of
1.14
by a city of 400,000 people in an area with (a) rainfall rate =
45 in.∕year = 114.3cm∕year; (b) evaporation rate = 20 in.∕year =
a city of 10,000 people?
50.8cm∕year; and (c) watershed catchment or drainage area =
1.15
Define the technical terms of (a) water supply system; (b)
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2
80 mile = 207.2km ?
community water system; (c) nontransient noncommunity water
1.6
Determine the net yield and water storage volume of a rain-
system; d) transient noncommunity water system; and (e) water-
water system assuming that (a) the net yield of a rain collection
shed.
facility approximates two-thirds of its gross yield; (b) the mean
Define the technical terms of (a) collection works or sys-
1.16
annual rainfall = 25 in.∕year = 63.5cm∕year; (c) the mean annual 1.13 Determine the diameter of a water main to serve a residen-
tems; (b) purification works; (c) transmission works or systems; (d)
evaporation rate is 8 in.∕year = 20.32 cm∕year; (d) the rain collec- distribution works or systems; and (e) impounding dams.
2
2
tion roof area equals 3,200 ft = 297.28 m ; and (e) water storage
volume equals 50% of annual net yield. 1.17 Define the technical terms of (a) aquifer; (b) water table; (c)
infiltration galleries; (d) well; and (e) artesian.
1.7 Determine the storage volume of a new raw water reservoir
in accordance with the following given technical information: (a) 1.18 Define the technical terms of (a) mixing basin or tank; (b)
city population = 400,000; (b) water consumption = 150 gpcd = flocculation or reaction basins; (c) sedimentation basins; (d) slow
2
2
568 Lpcd; (c) watershed or catchment area = 80 mi = 207.2km ; sand filtration; and (e) rapid sand filtration.
(d) rainfall rate = 45 in.∕year = 114.3cm∕year; (e) evaporation 1.19 Define the technical terms of (a) evaporation; (b) evapotran-
rate = 20 in.∕year = 50.8cm∕year; (f) minimum reservoir vol- spiration; (c) aeration; (d) desalination; and (e) reverse osmosis.
ume = 50% annual net yield or half of a year’s water supply, 1.20 Define the technical terms of (a) runoff; (b) fresh water;
whichever is greater; and (g) 75% water resources development. (c) saline and brackish waters; (d) precipitation; and (e) service
1.8 Determine the number of people who can be sustainably reservoir or distribution reservoir.
supported by a watershed under the following conditions: (a)
2
2
watershed area = 80 mi = 207.2km ; (b) annual rainfall rate =
45 in.∕year = 114.3cm∕year; (c) annual evaporation rate =
REFERENCES
20 in.∕year = 50.8cm∕year; (d) water resources development =
75%; (e) raw water reservoir volume to store 50% net annual
Al-Dhowalia, K. and Shammas, N. K., Leak detection and quan-
yield or provide half of a year’s water supply, whichever is
tification of losses in a water network, International Journal
higher = 13 BG = 49.205 BL; and (f) water consumption rate =
of Water Resources Development, vol. 7, no. 1, pp. 30–38,
150 gpcd = 568 Lpcd.
1991.
1.9 Determine the number of people who can be adequately sup-
American Water Works Association, Groundwater, AWWA Publi-
ported by a watershed under the following conditions: (a) water- cation, Denver, CO, 2003, 207 pp.
2
2
shed area = 80 mi = 207.2km ; (b) water supply system with
3
no reservoir for water storage; (c) low water flow = 0.1ft ∕s = American Water Works Association, Water Resources Planning,
2
3
64,600 gpd∕mi = 2.83 L∕s = 0.00283 m ∕s; and (d) water con- AWWA Publication, Denver, CO, 2007, 378 pp.
sumption rate = 150 gpcd = 568 Lpcd. American Water Works Association, Water Resources, AWWA Pub-
lication, Denver, CO, 2010, 210 pp.
1.10 Make a rough estimate of the groundwater movement veloc-
ity (v = Q/A) (ft/day or m/day) if (a) all of the groundwater laterally American Water Works Association, International Standard Units
within 400 ft (122 m) of the well comes fully within its influence; for Water and Wastewater Processes, AWWA Publication,
and (b) the yield of the aquifer is 258 gpm (gallon per minute) = Denver, CO, 2011, 90 pp.
976.53 L∕min = 16.28 L∕s; and the aquifer through which the Department of Water Supply Web Site, County of Maui, Hawaii,
groundwater moves is 25 ft (7.62 m) deep. http://mauiwater.org/, 2013.
2
2
1.11 Estimate the surface area (ft ,orm ) of a slow sand filter Fair, G. M., Geyer, J. C., and Okun, D. A., Water and Wastewater
that is to deliver water to a village of 1,000 people assuming that (a) Engineering, Vol. 1: Water Supply and Wastewater Removal,
the average daily water demand = 100 gpcd = 378.5 Lpcd; (b) the John Wiley & Sons, Inc., New York, 1966.
slow sand filter’s filtration rate is 3 million gallons per acre per day Fair, G. M., Geyer, J. C., and Okun, D. A., Elements of Water Supply
2
(MGAD) = 3MGD∕acre = 28.08 MLD∕ha = 2,808 MLD∕km ;
and Wastewater Disposal, John Wiley & Sons, Inc., New York,
and (c) two slow sand filters are required. Each filter is able to
1971.
treat the full water flow and one of the two filters is a standby
unit. National Resources Conservation Service, U.S. Department of
Agriculture, Water Supply Forecasting, http://www.wcc.nrcs
1.12 Estimate roughly the size of a water supply pipe lead-
.usda.gov/wsf/, 2013.
ing to a water distributing reservoir serving a small village of
2000 people assuming that (a) the water consumption rate is Orlob, G. T. and Lindorf, M. R., Cost of water treatment in Cali-
100 gpcd = 378.5 Lpcd and (b) water velocity in the pipe = 3ft∕s = fornia, Journal of American Water Works Association, vol. 50,
no. 45, pp. 45–55, 1958.
0.91 m∕s.