UNIVERSITY OF BOLTON SCHOOL OF ENGINEERING. MSc CIVIL ENGINEERING SEMESTER TWO EXAMINATION 2015/2016 URBAN DRAINAGE SYSTEMS MODULE NO: BLT4022

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1 TW5 UNIVERSITY OF BOLTON SCHOOL OF ENGINEERING MSc CIVIL ENGINEERING SEMESTER TWO EXAMINATION 015/016 URBAN DRAINAGE SYSTEMS MODULE NO: BLT40 Date: Tuesday 17 May 016 Time: INSTRUCTIONS TO CANDIDATES: There are FIVE questions. Answer FOUR questions. All questions carry equal marks. Marks for parts of questions are shown in brackets. This examination paper carries a total of 100 marks. All working must be shown. A numerical solution to a question obtained by programming an electronic calculator will not be accepted. A formula sheet and HRS tables are attached.

2 Page of 16 School of Engineering Semester Two Examination 015/016 Module No. BLT40 Question 1 a) Describe the natural purification processes taking place in a river reach and their contribution in reducing pollution in rivers. (5 marks) b) Explain your understanding of River Environmental Standards and Compliance Assessment of a river reach and who issue and oversee them (5 marks) c) The figure below shows two reaches of a river which serves as receiving water for a nearby town drainage system. The river receives final effluent from the town treatment work (FE), a combined sewer overflow (CSO), a Surface Water Outfall (SWO) and a runoff flow from rural catchment (CFB) at different locations as illustrated in Figure Q1. For a particular moment of time the values of flow and concentrations of the BOD, NH4 & DO for these inputs, as well as for the upstream end of the river reach (RBF), are given in Table 1. The percentage increase or decrease for the concentrations of BOD, NH4 & DO, due to the natural biochemical processes within the two reaches, is given in Table. i) Using the principle of mass balance and natural biochemical processes, find the concentrations of BOD, NH4 and DO in the river at locations P1, P, P3 and P4. (10 marks) ii) Carry out compliance assessment for the two reaches against the UK UPM standards for fishery (shown in Table 3) at same locations mentioned in (i). (5 marks) CFB SWO FE CSO RBF P3 P P1 P4 Reach1 3 Figure Q1 Question 1 continued over the page 1

3 Page 3 of 16 School of Engineering Semester Two Examination 015/016 Module No. BLT40 Question 1 continued Table 1: Input Data Input Name Flow C BOD C NH4 C DO m 3 /sec mg/l mg/l mg/l River Base Flow (RBF) Final Effluent (FE) Combined Sewer Overflow (CSO) Surface Water Outfall (SWO) Catchment Flow Boundary (CFB) Table : Effects of Biochemical Processes Process Reach1 Reach DO Percentage Increase by Aeration 0 15 DO Percentage Decrease by Biodegradation & Nitrification BOD Percentage Decrease by Biodegradation NH4 Percentage Decrease by Nitrification Table 3: Pollution Standards UPM Standards for Fishery Pass Fail DO >=5 <5 NH4 <=4 >4 Total 5 marks Please turn the page

4 Page 4 of 16 School of Engineering Semester Two Examination 015/016 Module No. BLT40 Question a) Explain the principles of sediment transportation. (8 marks) b) An 18m wide channel has a bed slope of The particles in the channel have a density of 50kg/m 3 and the particle size d 50 = 1.30mm. During a storm event the flow in the channel is raised to 5.8m 3 /s. Assuming uniform flow conditions, and µ: 1.14*10-3 ms/kg, determine whether sediment transportation occurs and if so whether particles are in bed-load or suspended load. (17 marks) Question 3 Total 5 marks Critically comment upon the shortcomings of conventional approaches to urban drainage design and outline the alternative sustainable techniques. Comment on the design and other issues that currently prevent their wider use. Discuss what systemic changes may be required to ensure their wider acceptance. Question 4 Total 5 marks a) Discuss the parameters that affect catchment response to rainfall in a rural area. Explain how urbanisation can impact some of these parameters and the consequence of this impact on the runoff hydrograph. (10 marks) b) Discuss the structural and non-structural mitigation measures of urbanisation impacts on a runoff hydrograph and give two examples for each of these measures. (10 marks) c) Explain your understanding for the concept of catchment modelling and differentiate between Blackbox, Conceptual and Physically-based mathematical models. (5 marks) Total 5 marks Please turn the page

5 150m Page 5 of 16 School of Engineering Semester Two Examination 015/016 Module No. BLT40 Question 5 a) For Site A in Figure 5A, provide a preliminary sketch for a storm drainage design. Assume a 75% runoff rate from grounds. Comment on all assumptions made. (9 marks) 100m 99.8m 99.6m 99.54m Building footprint and roof ridges 99.4m Site A boundary 170m Figure 5A - Site A Question 5 continued over the page

6 Page 6 of 16 School of Engineering Semester Two Examination 015/016 Module No. BLT40 Question 5 continued. b) During setting out and construction of the manholes on Site B the original drainage design was misinterpreted. The storm drains are now required to be connected into the Combined Sewer manhole MH C, see Figure 5B. i) Complete the Site B drainage scheme in Tables 5B-1 and 5B- by selecting suitable pipe diameters and gradients to accommodate a 1 in 0year storm event. (HRS tables and rainfall charts are provided). (1 marks) ii) Using Building Regulation Part H, state the bedding and surround requirements for all pipes in the storm drainage network. (3 marks) Total 5 marks Please turn the page

7 Page 7 of 10 MHC1 MHC MH MH3 1.0 MH4 Grassed area to drain through infiltration due to very permeable soil conditions MH1 MH5 Building footprint 36m 5m Site B boundary

8 School of Engineering Semester Two Examination 015/016 Module No. BLT40 Page 8 of 16 Manhole No. Cover level (m) Site B - Manhole Schedule Invert level (m) Ground catchment area (Ha) Roof catchment area (Ha) MH MH MH MH MH MTC n/a n/a MHC n/a n/a Table 5B-1 Table Q5B-1. To be handed in with answer book Candidate ID No... Please turn the page

9 School of Engineering Semester Two Examination 015/016 Module No. BLT40 Page 9 of 16 Pipe No Pipe Length (m) Pipe gradient (1 in ) Pipe fall (m) Vel (m/s) Time of flow (min) Time of Conc. (min) Rate of rainfall i (mm/hr) Imp. Area (ha) Cumulative Imp. Area (ha) Flow Q (l/s) Pipe dia. (mm) Pipe capacity (l/s) Table Q5B-. To be handed in with answer book Candidate ID No... END OF QUESTIONS Please turn the page

10 Page 10 of 16 School of Engineering Semester Two Examination 015/016 Module No. BLT40 Formula A = DWF P + E l/d DWF = PG + I + E D MIN = 0.7 Q MAX 0.4 F r = 4.06 Q 0.5 gd 5 Q O = C D x A O x ( x g x H O ) 0.5 Formula sheet H O = 1.D + 0.5D O C D = db Do u db - D o d B =.5 x D MIN, L = 7 x D MIN s = 0.8D + D O Q w = C Qw H w = C C 1 = 3 1 C d d 3 Q C 3 3/ g LH w w g L Q C 3 w 3,C gl s K 1,C 3 gl t K, C d = 0.7, K 1, K =.0 h f = S o x L n=(sinθ)d 1/6, τ o = ρgrs V = τ o ρ τ = τ O ρ(s 1)gd s Please turn the page

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UNIVERSITY OF BOLTON SCHOOL OF ENGINEERING. MSc CIVIL ENGINEERING SEMESTER TWO EXAMINATION 2017/2018 URBAN DRAINAGE SYSTEMS MODULE NO: BLT4022

[ESS29] UNIVERSITY OF BOLTON SCHOOL OF ENGINEERING MSc CIVIL ENGINEERING SEMESTER TWO EXAMINATION 2017/2018 URBAN DRAINAGE SYSTEMS MODULE NO: BLT4022 Date: Monday 21 st May 2018 Time: 10:00 13:00 INSTRUCTIONS