- A Total Of 55 Marks Can Be Obtained Including The 3 Marks Mentioned Above Any Tp108 Calculation Will Have To Be Based O 1 (375.61 KiB) Viewed 76 times
1) Stormwater Management Requirements: a. Is detention required? Please justify your answer? [2marks) b. Is retention required? Please justify your answer? [2marks) C. What is the highest imperviousness allowed for each lot? Justify and specify the source of information. [2marks] 2) Preliminary Stormwater Pipe Design for the 10year ARI storm event: a. Define the contributing catchment to pipe A assuming that each property's impervious and pervious areas are connected to the SW network by lateral connection or kerb discharge. [4marks) b. Calculate and specify the minimum required pipe size based on AC SW COP (Auckland Council Code of Practice) for Pipe A using TP108. Remember the minimum time of concentration required by TP108 and to include climate change as per AC SW COP table 1. Make sure the flow velocities (min and max) are acceptable and that cover and slope also satisfy Auckland Council code of practice. In addition to that: • The geology of the catchment is described in a borehole log attached to this document in Appendix A. • If the time of concentration of the largest of your catchments is equal or below 0.17hrs, use 0.17hr for all catchments. [20marks] C. How does your proposed design compare with the existing network? Is the current pipe going to be adequate in 2090? [4marks] 3) Stormwater Management: a. Discuss at least two potential stormwater management devices that you could adopt onsite to meet the requirements discussed in question 1 and justify. [4marks) b. Based on GD01 section C5, design a rainwater tank based on the following assumptions; • 23 Renoir Street is going to be demolished and rebuilt, so the property can be classified as a brownfield. • Assuming that the maximum roof area is 50% of the property and that 100% of the roof area is connected to the rainwater tank. Make sure to specify the various orifices diameter and elevation. [10marks]
4) Over Land Flow Path (OLFP): a. Assuming that the driveway of 41 Renoir Street is 5m wide, what would be the depth of water in the overland flowpath running through the property at the location illustrated below? [4marks) 31 OLFP
Appendix B BOREHOLE No. 3 Engineering Geology Ltd SITE: 171 Luckens Road, WEST HOBSONVILLE : REF 4193 Sheet 1 of 1 DESCRIPTION OF SOIL CORRECTED VANE SHEAR STRENGTH (kPa) ( Fuld vane (stam) Randole 50 100 150 FILL: clay/sit, organic rich, firm, moist, intermixed, dk brown, brown and orange brown . . ORGANIC SILT, s. clayey, sl. sandy(f), stiff, moist, dk grey/brown with occ, black specks, occ. dk orange brown mottles, occ. gum Inclusions CLAY, silly, firm, moist - wet, highly plastic, OCC It brown angular silt clasts . Slip Debris brown/grey with dk brown organic staining . ICLAY, silty, firm, moist, mod. plastic, moist - wet, It grey with orange brown staining, occ. brown organic specks OCC. red/brown streaks / it grey with occ. orange brown and red/brown . mottles 3 - . increased silt Waitemata Group soils 46 Occ. sl. sandy(t) horizons . It grey with it red/brown staining . . 11 E.O.B. 50 m NOTES LOGGED BY: MW DATE DRILLED: 24-Sep-09 DRILL METHOD: 50 mm Hand Agar