CEB319-T1-S1-2007

CEB319-T1-S1-2007 - GUT Surname Given Name/s III-III...

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Unformatted text preview: GUT Surname Given Name/s III-III- Examination Paper SEMESTER: FIRST SEMESTER EXAMINATIONS 2007 UNIT: CEBB19 WATER ENGINEERING - THEORY 1 DURATION OF EXAMINATION: PERUSAL: 10 MINUTES WORKING: 2HOURS EXAMINATION MATERIAL SUPPLIED BY THE UNIVERSITY: EXAMINATION BOOKLETS EQUATION SHEET - ONE (1) PAGE ATTACHED GRAPHS - FOUR (4) PAGES ATTACHED EXAMINATION MATERIAL SUPPLIED BY THE STUDENT: WRITING IMPLEMENTS CALCULATORS - ANY TYPE INSTRUCTIONS TO STUDENTS: Students are prohibited from having mobile phones or any other device capable of communicating information (either verbal or written) in their possession during the examination NOTES MAY BE MADE QNLX ON THE EXAMINATION PAPER DURING PERUSAL TIME ALL EIGHT (8) QUESTIONS ARE TO BE ATTEMPTED MARKS FOR EACH QUESTION ARE AS INDICATED Queensland University of Technology GUT GUT GUT GUT Gardens Point Kelvin Grove Carseldine Caboolture QUESTION 1 (a) Determine time of concentration (tc) for a catchment with area of 1428ha, drainage length of 5.4km and equal area slope of 1.05%. (3 marks) (b) The catchment described above is located at Killarney, South East Queensland, and has physical characteristics which can be described as steep country with a well defined drainage system. The catchment ground cover is open forested. Calculate the peak runoff for a lOyear ARI storm event. Refer Attachments for additional information needed for calculations. (7 marks) f QUESTION 2 Part of a catchment located at Killarney, South East Queensland is developed as high density urban residential. Rest of the catchment is rural residential. Total catchment area is 90ha and 40% of the total area is high density urban residential. Assuming time of concentration (to) as 36min, determine the peak discharge for a lOOyear ARI storm event. Fraction imperviousness for high density urban residential and rural residential are 0.8 and 0.2 respectively. Refer Attachments for additional information needed for calculations. (10 Marks) QUESTION 3 (a) Table 1 below shows details of a rainfall event recorded for a rural catchment of 3.2km2. The runoff volume measured at the catchment outlet is 65600m3. Using initial loss/continuing loss rate model determine the continuing loss rate in mm/hr. Initial loss for the rainfall is estimated as 21mm. (6 marks) Table l —- Rainfall Hyetograh Rainfall mm/hr 0-10 48 — 42 40-50 50-60 24 (b) If the catchment mentioned above is developed so that the impervious surfaces are 50% of the total area, determines the percentage increase in runoff volume compared to rural catchment. Initial loss for impervious surfaces is 5mm and no continuing loss. (4 marks) CEB319T1.071 cont/... QUESTION 4 Water flows in a 2.3m wide rectangular channel at a depth of 1.7m under uniform condition. The Manning’s roughness and bed slope are 0.03 and 0.5% respectively. (a) Determine the discharge in the channel. (4 marks) (b) 40% of the channel discharge is diverted to a triangular channel with cross section shape as shown in Figure l. Manning’s roughness and slope of the triangular channel are 0.005 and 1.2% respectively. Determine the flow depth in triangular channel. Figure 1 —— Triangular channel cross section (6 marks) QUESTION 5 As seen in Figure 2 below, water flows in a 3m wide rectangular channel at a depth of 1.5m. Flow in the channel is 4.5m3/s. (a) Is the flow subcritical or supercritical (2 marks) (b) Determine the critical depth for the discharge (2 marks) (0) At Section 2, 1m wide bridge pier is placed. Will critical depth occur in this Section? Justify your answer with calculations. (3 marks) (d) At Section 3, a frictionless hump is placed in the channel. Determine the maximum hump height so that the upstream pooling does not occur. (3 marks) § Q) @ 6) Figure 2 - Open channel (plan View) CEB319T1.071 cont/. .. QUESTION 6 A culvert consisting of 3 boxes is placed to convey storrnwater under a road embankment. Each box is 1.2m high and 1.5m wide. Length of the culvert is 60m and is laid on a bed slope of 1.2%. The culvert has wing walls with flare angle of 750 and the entrance energy loss coefficient (kc) is 0.5. Assuming that the maximum allowable head water level is 2.4m above the upstream invert of the culvert, determine the maximum flow that can pass through. The estimated tailwater depth is 1.2. Refer to Attachments for additional information needed for calculations. (10 marks) QUESTION 7 A hydraulic jump occurs in a 2.3m wide horizontal rectangular channel. The depth before and after the jump are 0.3 and 1.1m respectively. (a) Determine the flow rate in the channel (4 marks) (b) Determine the head loss due to the hydraulic jump (2 marks) (0) Determine alternative depth for the flow upstream of the hydraulic jump. Explain the reason for not maintaining alternate depth after the jump. (4 marks) QUESTION 8 (a) Briefly explain the changes to runoff hydrograph due to urbanisation (4 marks) (b) In comparison to the Rational Method discuss the advantages and disadvantages of using a runoff routing model such as WBNM for peak flow analysis. (3 marks) (0) Discuss details of three flow measuring techniques / devices that can be used in open channel flow. (3 marks) END OF PAPER CEB319T1.071 (i) 0E3319 EQUATION SHEET Hydrology Flow measuring devices fl 2 _ 3/2 Qy=0.2780y1w,yA Q " Cd 3 [234“ 58L 3/2 [c = AIL/33.2 Q = CwLH ._ 8 9 5/2 Cy—CloFy Q=C —" 2gtan—I—I (115 2 - Fy =O.54Loglo (y) + 0.46 Q = KHS/Z Q = AV = xn/gyg = L(2/3)3/2\/§132/3 cm = 0.9.1" + c}0.(1- r) 010 = 0.1+ 0.0133.(‘°1,—25) I E N2 ("7) ‘ N+0.2 \f3— H N 02 mm = "1:04 Q = achq/Zgh = CCCVAngh = CdAJ2gh 1 _ ‘ V2 =<-W—2\/2g(y.-y2) . Open channel flow \/1"(A2 U11) V___R2/BSl/2 n V2 E—y+2—g' _ 3.9: E~y+2g yz q=xlgyi Vc =fl’gyc :39— 3 Ec"Emin Eye Fr =_Z_ x/gy y, =323-(~1+J1+8F,?) y2 =%(~1+J1+8F3) CEB319T1.071, . Rainfalllntensi Fre uenc Duration datafor Killarne LD Geographic location 28.33 South 152.33 East Duration 1year ARI 2year ARl 5year ARI 10year ARI 20year ARI 50year ARI 100year ARI mlnr mmlhour mmlhour mmlhour mmlhour mmlhour mmlhour mmlhour "-21- -_ -3- _§— “.55- “n m:- m- 1.“ -E- .m— ‘1»- m.“ 49.2 ‘2- 48.2 “.31?- .35— -3:- “"12- ‘1. CEB319T1.071 Road Drainage Design Manual Chapter 3: Hydrology and Design Criteria Table 3.5 Estimation of the Runoff Coefficient for Rural Catchments Runoff Producing Values (in brackets) as % in calculation of “C” for a 50 year average recurrence interval event Characteristics Rainfall 100 mmih 75-100 mmih 50-75 mmih 25-50 mmih 12~25 mmih 12 mmih <12 mmih Intensity (35) (30). (25) (15) (10) (5) (0) Relief Very steep Steep country, Hilly. with Rolling with Flat, with rugged country slopes 8-15% slopes of 4-8% slopes 1.541% slopes 04.5% with average slopes > 15% (10) (5) (5) (0) (0) Storage Negligible. few surface Well defined system Considerable surface Poorly defined and depressions. water- of small depressions. overland meandering stream, courses. steep and thin watercourses flow is significant. some large surface film of overland flow farm ponds. swamps storage. Soil and contour banks conservation plan on 90% catchment (10) (10) (5) (0) Ground Rocky, clayey or Open forest or Average Heavily Sands or well Cover non-absorbent grassed land, grassed timbered aggregated Characteristics soil with cereal crops timbered land country. closely soil scanty of medium soil cultivated land herbage texture and garden (45) (40) (35) (30) (10) Notes: 1. For catchments > 50 km”. use with extreme caution. 2. Use values below 50% with caution. 3. Use values above 80% only in very high rainfall areas (absolute maximum of 90%) where the antecedent precipitation conditions for the design storm is a saturated catchment. Example: A catchment has the following characteristics: (i) intensity 4O mm/hr (ii) Hilly, average slopes 4-8°/o (iii) Well defined system of small watercourses (iv) Open forest 15+5+10+4O 100 = 0.70 Source: Hee (1978). 3-26 June 2003 CEB319T1.071 (iv) HYDRAULICS OF PRECAST CONCRETE CONDUITS OD SECTION 3 5500 5000 ~ 140 4500 120 - 4200 100 - 3900 3500 example scam ngwall [lam D 600 mm - D 3800* 0 , .s,‘ C. 0-8 - 110m em 50 ‘ (I) (“rm”), '18 3000* _ Hw 40 ~ 90" and ‘5' "—6—- me) t3) 0" (extanmons of mans) 3 30 2700 V m 1‘75 “0 To use scale (2) or (3) meme! 5 (2) 1'90 H ‘ ' horizontally in scale ('1). Ihan use 5 2400 (3) 2'04 "2 2° 7, straight mclinoci nne Hunugh D and 0 50mm. or revmse as 4 unusualed. 2100 3 10 *- 1300» ' ,r I 2 1500 - 5 4 - - 1.5 (a 3 'f P‘gfiwu 1200— g Q' 2 . Angie ol . . 1‘0 wlngwul! - ' ‘ ' "” , flare . w...“ 900 ’ 1 ‘ .9 1' r ---Ua . . ‘8 750 C. a '7 r:_ _ .4 ~ 33 a, _‘ g .6 600- — 3 _ u g s E “ 1” O n x: E ‘5’ .5 :- -2 ‘ .E a: 9 ’ a E 450v u- s E o E a " ‘4 F' 1 - a o I 9 ' ‘5 55 LU ' a: y. 3: ‘ 4 g 2 E o E ‘2 a w '05 .. .. Q I v .3 E 300~~ - " HEADWATEH DEPTH FOR 80X CULVERTS WITH INLET CONTROL FIGURE 3.4 ADAPTED FROM [3.4] Page 34 CEB319T1.071 (V) HYDRAULICS OF PRECAST CONCRETE CONDUITS OD SECTION 3 150 l .. o o Turnmg Line Area (A) of rectangular box in m? Discharge (O) in cumecs V ; r i . £- 0 =2.4 m’lls Mu“ “wwow v... ' -2 ENERGY HEAD H FOR CONgEEIE BOX CULVERTS FLOWING n = 0011 FIGURE 3.5 ADAPTED FROM [3.41 NOTE: (a) For a different value at n. use the length scale -- shown with an adjusted length L. = Ltnrlnlfi "-5 (b) For a difterent value ol kt, connect the given ' length on adjacent scales by a straight line and select a point on this line spaced from the two chart scales in proportion to the k.. values. '4 (c) For areas less than 0.8m2 and boxes with width to height ratios greater than 2 or less than 1. r .3 determine H from H = [1 + k" + 1926?.“tlfklw9? RM, 2gA2 2 .14 Page 36 CEB319T1.071 ...
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This note was uploaded on 04/26/2010 for the course EN 40 taught by Professor Mcgregor during the Two '10 term at Queensland Tech.

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CEB319-T1-S1-2007 - GUT Surname Given Name/s III-III...

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